From 464df1d5e5ab1322e2dd0a7796939fff1aeefa9a Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 17:49:25 +0200 Subject: Adding upstream version 1.47.0. Signed-off-by: Daniel Baumann --- ext2ed/COPYRIGHT | 346 ++++ ext2ed/Makefile.in | 97 ++ ext2ed/README | 160 ++ ext2ed/blockbitmap_com.c | 266 +++ ext2ed/dir_com.c | 678 ++++++++ ext2ed/disk.c | 239 +++ ext2ed/doc/ext2ed-design.sgml | 3459 +++++++++++++++++++++++++++++++++++++++ ext2ed/doc/ext2fs-overview.sgml | 1569 ++++++++++++++++++ ext2ed/doc/user-guide.sgml | 2258 +++++++++++++++++++++++++ ext2ed/ext2.descriptors | 976 +++++++++++ ext2ed/ext2_com.c | 98 ++ ext2ed/ext2ed.8.in | 72 + ext2ed/ext2ed.conf.in | 79 + ext2ed/ext2ed.h | 435 +++++ ext2ed/file_com.c | 565 +++++++ ext2ed/general_com.c | 907 ++++++++++ ext2ed/group_com.c | 183 +++ ext2ed/init.c | 633 +++++++ ext2ed/inode_com.c | 437 +++++ ext2ed/inodebitmap_com.c | 215 +++ ext2ed/main.c | 548 +++++++ ext2ed/super_com.c | 156 ++ ext2ed/win.c | 232 +++ 23 files changed, 14608 insertions(+) create mode 100644 ext2ed/COPYRIGHT create mode 100644 ext2ed/Makefile.in create mode 100644 ext2ed/README create mode 100644 ext2ed/blockbitmap_com.c create mode 100644 ext2ed/dir_com.c create mode 100644 ext2ed/disk.c create mode 100644 ext2ed/doc/ext2ed-design.sgml create mode 100644 ext2ed/doc/ext2fs-overview.sgml create mode 100644 ext2ed/doc/user-guide.sgml create mode 100644 ext2ed/ext2.descriptors create mode 100644 ext2ed/ext2_com.c create mode 100644 ext2ed/ext2ed.8.in create mode 100644 ext2ed/ext2ed.conf.in create mode 100644 ext2ed/ext2ed.h create mode 100644 ext2ed/file_com.c create mode 100644 ext2ed/general_com.c create mode 100644 ext2ed/group_com.c create mode 100644 ext2ed/init.c create mode 100644 ext2ed/inode_com.c create mode 100644 ext2ed/inodebitmap_com.c create mode 100644 ext2ed/main.c create mode 100644 ext2ed/super_com.c create mode 100644 ext2ed/win.c (limited to 'ext2ed') diff --git a/ext2ed/COPYRIGHT b/ext2ed/COPYRIGHT new file mode 100644 index 0000000..5585eb6 --- /dev/null +++ b/ext2ed/COPYRIGHT @@ -0,0 +1,346 @@ +EXT2ED is hereby placed under the terms of the GNU General Public License. +Follows the GNU license. + +Gadi Oxman, August 1995 + +--------------------------------------------------------------------------- + + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc. + 675 Mass Ave, Cambridge, MA 02139, USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. 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It is safest +to attach them to the start of each source file to most effectively +convey the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + + Copyright (C) 19yy + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + + Gnomovision version 69, Copyright (C) 19yy name of author + Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, the commands you use may +be called something other than `show w' and `show c'; they could even be +mouse-clicks or menu items--whatever suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the program + `Gnomovision' (which makes passes at compilers) written by James Hacker. + + , 1 April 1989 + Ty Coon, President of Vice + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Library General +Public License instead of this License. diff --git a/ext2ed/Makefile.in b/ext2ed/Makefile.in new file mode 100644 index 0000000..e4724ca --- /dev/null +++ b/ext2ed/Makefile.in @@ -0,0 +1,97 @@ +# +# Standard e2fsprogs prologue.... +# + +srcdir = @srcdir@ +top_srcdir = @top_srcdir@ +VPATH = @srcdir@ +top_builddir = .. +my_dir = ext2ed +INSTALL = @INSTALL@ +MKDIR_P = @MKDIR_P@ + +@MCONFIG@ + +PROGS= ext2ed +MANPAGES= ext2ed.8 + +DOC_DIR = $datadir/doc/ext2ed + +LIBS = -lncurses $(LIBEXT2FS) + +SRCS= $(srcdir)/main.c $(srcdir)/init.c $(srcdir)/general_com.c \ + $(srcdir)/inode_com.c $(srcdir)/dir_com.c $(srcdir)/super_com.c \ + $(srcdir)/disk.c $(srcdir)/win.c $(srcdir)/group_com.c \ + $(srcdir)/file_com.c $(srcdir)/blockbitmap_com.c \ + $(srcdir)/ext2_com.c $(srcdir)/inodebitmap_com.c + +OBJS= main.o init.o general_com.o inode_com.o dir_com.o super_com.o \ + disk.o win.o group_com.o file_com.o blockbitmap_com.o ext2_com.o \ + inodebitmap_com.o + +DOCS= doc/ext2ed-design.pdf doc/user-guide.pdf doc/ext2fs-overview.pdf \ + doc/ext2ed-design.html doc/user-guide.html doc/ext2fs-overview.html + +.c.o: + $(CC) -c $(ALL_CFLAGS) $< -o $@ + $(CHECK_CMD) $(ALL_CFLAGS) $< + $(CPPCHECK_CMD) $(CPPFLAGS) $< + +.SUFFIXES: .sgml .ps .pdf .html + +.sgml.ps: + mkdir -p doc + sgmltools -b ps $< + -mv `echo $< | sed -e 's/.sgml$$/.ps/'` $@ + +.sgml.pdf: + mkdir -p doc + sgmltools -b pdf $< + -mv `echo $< | sed -e 's/.sgml$$/.pdf/'` $@ + +.sgml.html: + mkdir -p doc + sgmltools -b onehtml $< + -mv `echo $< | sed -e 's/.sgml$$/.html/'` $@ + +all:: $(PROGS) $(MANPAGES) ext2ed.conf + +docs: $(DOCS) + +ext2ed: $(OBJS) + $(CC) $(ALL_LDFLAGS) -o ext2ed $(OBJS) $(LIBS) + +ext2ed.8: $(DEP_SUBSTITUTE) $(srcdir)/ext2ed.8.in + $(SUBSTITUTE_UPTIME) $(srcdir)/ext2ed.8.in ext2ed.8 + +ext2ed.conf: $(DEP_SUBSTITUTE) $(srcdir)/ext2ed.conf.in + $(SUBSTITUTE_UPTIME) $(srcdir)/ext2ed.conf.in ext2ed.conf + +clean:: + $(RM) -f ext2ed $(OBJS) $(DOCS) ext2ed.conf ext2ed.8 + -rmdir doc + +install: ext2ed + install -d $(root_sysconfdir) + install -m 755 ext2ed $(sbindir) + install -m 644 $(srcdir)/ext2.descriptors $(datadir) + install -m 644 ext2ed.conf $(root_sysconfdir) + install -m 644 ext2ed.8 $(man8dir) + +# +++ Dependency line eater +++ +# +# Makefile dependencies follow. This must be the last section in +# the Makefile.in file +# +main.o: $(srcdir)/main.c $(srcdir)/ext2ed.h +general_com.o: $(srcdir)/general_com.c $(srcdir)/ext2ed.h +inode_com.o: $(srcdir)/inode_com.c $(srcdir)/ext2ed.h +dir_com.o: $(srcdir)/dir_com.c $(srcdir)/ext2ed.h +super_com.o: $(srcdir)/super_com.c $(srcdir)/ext2ed.h +disk.o: $(srcdir)/disk.c $(srcdir)/ext2ed.h +win.o: $(srcdir)/win.c $(srcdir)/ext2ed.h +group_com.o: $(srcdir)/group_com.c $(srcdir)/ext2ed.h +file_com.o: $(srcdir)/file_com.c $(srcdir)/ext2ed.h +blockbitmap_com.o: $(srcdir)/blockbitmap_com.c $(srcdir)/ext2ed.h +ext2_com.o: $(srcdir)/ext2_com.c $(srcdir)/ext2ed.h +inodebitmap_com.o: $(srcdir)/inodebitmap_com.c $(srcdir)/ext2ed.h diff --git a/ext2ed/README b/ext2ed/README new file mode 100644 index 0000000..1f473cf --- /dev/null +++ b/ext2ed/README @@ -0,0 +1,160 @@ +ext2ed - The extended-2 filesystem editor, version e2fsprogs + + +This version of ext2ed has been modified and updated by Theodore Ts'o +for inclusion with the e2fsprogs package. It now builds with modern +ncurses and I've fixed various small bugs, particular in the redrawing +and resizing functions. + +It is currently not built by default -- the top-level e2fsprogs +Makefile doesn't recurse into this directory. This is because ext2ed +has a number of VERY SERIOUS shortcomings: + +1) It doesn't work on filesystems bigger than 2GB + +2) It assumes that all's the world an Intel, and assumes that + everything is in Intel (little-endian) byte order. + +Fixing either of these problems would be non-trivial, and so I at this +point DO NOT RECOMMEND that distributions try to include this program, +even as modified and updated in e2fsprogs. This especially goes for +Debian, where the Debian maintainer for e2fsprogs has a history of +making authorized changes to e2fsprogs to include programs that aren't +supported, and then starts bugging me with bug reports. YES I KNOW. +THIS PROGRAM HAS HORRIBLE SHORTCOMINGS. IT IS INCLUDED HERE ONLY +BECAUSE IT'S A CONVENIENT WAY FOR (FOR E2FSPROGS DEVELOPERS ON INTEL +MACHINES) TO GENERATE TEST CASES BY SELECTIVELY CORRUPTING +FILESYSTEMS. I WILL NOT SUPPORT THIS PROGRAM FOR USE BY GENERAL USERS +SO PLEASE DO NOT INCLUDE IT IN A DISTRIBUTION. + +I have currently disabled the use of GNU Readline in this program, +because readline and ncurses really don't play well together at all. +Readline assumes that it can write arbitrary text to the screen +(especially when it tries to print out a completion list), which just +doesn't work with ncurses. Fixing this so they would work together +would require wholesale changes to readline. + + Theodore Ts'o + tytso@MIT.EDU + May 12, 2001 + +---------------------------------------------------------------------------- + +ext2ed - The extended-2 filesystem editor, version 0.2 +------------------------------------------------------ + +This is version 0.2 of ext2ed - The extended-2 filesystem editor. + +Modifications on Apr 5 2001 +This is minor bug fixes to ext2ed, as of April 2001. +It supports modern ext2 version that has file type in directory structure +and fixes the misunderstanding between ncurses and +readline. + +I first applied patches from Red Hat except the one for readline that +rewrote a readline behavior. + +Globals diffs between version 0.1 and 0.2 is stored in file : + diff-ext2ed.1.2 + +Christian Bac + +---------------------------------------------------------------------------- + +Documentation +------------- + +ext2ed's documentation consists of three documents: + +1. The user's guide. +2. Technical overview of the ext2 filesystem. +3. The EXT2ED design and implementation document. + +Those documents are available in the doc directory, in linuxdoc-sgml and +postscript formats. + +The documentation is also available online at: + +http://tochnapc2.technion.ac.il + +under the ext2ed section. + +Installation +------------ + +ext2ed requires the kernel sources and the readline and ncurses packages. +Please edit the makefile if you are using an "old" version of ncurses (See the +details below) or if gcc can't find the various header files and libraries. + +To install, simply issue a 'make' command to compile and a 'make install' +command to install. I have also included an already compiled linux a.out +binary. + +ext2ed and ncurses +------------------ + +ext2ed uses the ncurses library for terminal output. It is very important +that ncurses will be properly installed on your system: + +1. Old versions of ncurses (around 1.8.5) need the OLD_NCURSES compile + time option in EXT2ED. + + At least from 1.9.2c, this flag should not be used. I would recommend + upgrading the ncurses library to the newer versions. + +2. ncurses uses its own terminfo database rather then the termcap file. + It is important that the terminfo database will be found by ncurses. + If this is not the case, you will see on startup some lines which + refer to /etc/termcap. This will mean that there is a problem with + the terminfo database. + +3. Newer versions of ncurses (and the 1.3 series of the kernel) describe + the linux console in the entry 'linux' and not 'console', as it was + before. If you run ext2ed in the linux console, you should either + set your TERM environment variable to 'linux' or link + l/linux to c/console in the terminfo database. + +4. The precompiled binary was linked with ncurses 1.9.4 and will search + for the terminfo database on /usr/local/lib/terminfo. If you are + using it, and your 1.9.4 compatible terminfo database is not on the + directory above, use the TERMINFO environment variable to specify + an alternate location. + +Running ext2ed +-------------- + +For those of you who don't like reading lengthy articles, here are a few +basic guidelines: + +1. Don't use ext2ed to change a mounted filesystem ! + + Using ext2ed in read-only mode on a mounted filesystem can be allowed + by using the configuration file option 'AllowMountedRead on'. However, + note that the displayed data will be unreliable. + +2. ext2ed currently can't handle filesystems bigger than 2 GB. I am + sorry for the inconvenience. This will hopefully be fixed in future + releases. + +3. Before running ext2ed, edit the configuration file + /var/lib/ext2ed/ext2ed.conf to suit your needs. The various + configuration options are documented there. + +4. Use the 'setdevice' command to open an ext2 filesystem. + e.g. 'setdevice /dev/hda1'. + +5. If the filesystem is an ext2 filesystem and ext2ed fails to + autodetect this, use the 'ForceExt2 on' configuration file option. + +6. The filesystem will always be opened in read-only mode. Feel free to + experiment, but take care with the 'enablewrite' command. + +----------------------------------------------------------------------------- + +Feel free to send me feedback with anything regarding to ext2ed. + +Enjoy, + +Gadi Oxman +Haifa, August 23 1995 + diff --git a/ext2ed/blockbitmap_com.c b/ext2ed/blockbitmap_com.c new file mode 100644 index 0000000..53e61dc --- /dev/null +++ b/ext2ed/blockbitmap_com.c @@ -0,0 +1,266 @@ +/* + +/usr/src/ext2ed/blockbitmap_com.c + +A part of the extended file system 2 disk editor. + +------------------------- +Handles the block bitmap. +------------------------- + +This file implements the commands which are specific to the blockbitmap type. + +First written on: July 5 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include + +#include "ext2ed.h" + +/* + +The functions in this file use the flobal structure block_bitmap_info. This structure contains the current +position in the bitmap. + +*/ + +void type_ext2_block_bitmap___entry (char *command_line) + +/* + +This function changes the current entry in the bitmap. It just changes the entry_num variable in block_bitmap_info +and dispatches a show command to show the new entry. + +*/ + +{ + unsigned long entry_num; + char *ptr,buffer [80]; + + + + ptr=parse_word (command_line,buffer); /* Get the requested entry */ + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n"); + refresh_command_win (); return; + } + ptr=parse_word (ptr,buffer); + + entry_num=atol (buffer); + + + if (entry_num >= file_system_info.super_block.s_blocks_per_group) { /* Check if it is a valid entry number */ + + wprintw (command_win,"Error - Entry number out of bounds\n"); + refresh_command_win ();return; + } + + + + block_bitmap_info.entry_num=entry_num; /* If it is, just change entry_num and */ + strcpy (buffer,"show");dispatch (buffer); /* dispatch a show command */ +} + +void type_ext2_block_bitmap___next (char *command_line) + +/* + +This function passes to the next entry in the bitmap. We just call the above entry command. + +*/ + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",block_bitmap_info.entry_num+entry_offset); + dispatch (buffer); +} + +void type_ext2_block_bitmap___prev (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",block_bitmap_info.entry_num-entry_offset); + dispatch (buffer); +} + +void type_ext2_block_bitmap___allocate (char *command_line) + +/* + +This function starts allocating block from the current position. Allocating involves setting the correct bits +in the bitmap. This function is a vector version of allocate_block below - We just run on the blocks that +we need to allocate, and call allocate_block for each one. + +*/ + +{ + long entry_num,num=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); /* Get the number of blocks to allocate */ + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + num=atol (buffer); + } + + entry_num=block_bitmap_info.entry_num; + /* Check for limits */ + if (num > file_system_info.super_block.s_blocks_per_group-entry_num) { + wprintw (command_win,"Error - There aren't that much blocks in the group\n"); + refresh_command_win ();return; + } + + while (num) { /* And call allocate_block */ + allocate_block (entry_num); /* for each block */ + num--;entry_num++; + } + + dispatch ("show"); /* Show the result */ +} + +void type_ext2_block_bitmap___deallocate (char *command_line) + +/* This is the opposite of the above function - We call deallocate_block instead of allocate_block */ + +{ + long entry_num,num=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + num=atol (buffer); + } + + entry_num=block_bitmap_info.entry_num; + if (num > file_system_info.super_block.s_blocks_per_group-entry_num) { + wprintw (command_win,"Error - There aren't that much blocks in the group\n"); + refresh_command_win ();return; + } + + while (num) { + deallocate_block (entry_num); + num--;entry_num++; + } + + dispatch ("show"); +} + + +void allocate_block (long entry_num) + +/* In this function we convert the bit number into the right byte and inner bit positions. */ + +{ + unsigned char bit_mask=1; + int byte_offset,j; + + byte_offset=entry_num/8; /* Find the correct byte - entry_num/8 */ + /* The position inside the byte is entry_num %8 */ + for (j=0;j0;i--) + j*=2; + if ((*ptr) & j) + wprintw (show_win,"Allocated\n"); + else + wprintw (show_win,"Free\n"); + refresh_show_win (); +} diff --git a/ext2ed/dir_com.c b/ext2ed/dir_com.c new file mode 100644 index 0000000..67bb4b5 --- /dev/null +++ b/ext2ed/dir_com.c @@ -0,0 +1,678 @@ +/* + +/usr/src/ext2ed/dir_com.c + +A part of the extended file system 2 disk editor. + +-------------------- +Handles directories. +-------------------- + +This file contains the codes which allows the user to handle directories. + +Most of the functions use the global variable file_info (along with the special directory fields there) to save +information and pass it between them. + +Since a directory is just a big file which is composed of directory entries, you will find that +the functions here are a superset of those in the file_com.c source. + +We assume that the user reached here using the dir command of the inode type and not by using settype dir, so +that init_dir_info is indeed called to gather the required information. + +type_data is not changed! It still contains the inode of the file - We handle the directory in our own +variables, so that settype ext2_inode will "go back" to the inode of this directory. + +First written on: April 28 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include + +#include "ext2ed.h" + +char name_search [80]; +long entry_num_search; + +int init_dir_info (struct struct_file_info *info_ptr) + +/* + +This function is called by the inode of the directory when the user issues the dir command from the inode. +It is used to gather information about the inode and to reset some variables which we need in order to handle +directories. + +*/ + +{ + struct ext2_inode *ptr; + + ptr=&type_data.u.t_ext2_inode; /* type_data contains the inode */ + + info_ptr->inode_ptr=ptr; + info_ptr->inode_offset=device_offset; /* device offset contains the inode's offset */ + + /* Reset the current position to the start */ + + info_ptr->global_block_num=ptr->i_block [0]; + info_ptr->global_block_offset=ptr->i_block [0]*file_system_info.block_size; + info_ptr->block_num=0; + info_ptr->file_offset=0; + /* Set the size of the directory */ + + info_ptr->blocks_count=(ptr->i_size+file_system_info.block_size-1)/file_system_info.block_size; + info_ptr->file_length=ptr->i_size; + + info_ptr->level=0; /* We start using direct blocks */ + info_ptr->display=HEX; /* This is not actually used */ + + info_ptr->dir_entry_num=0;info_ptr->dir_entries_count=0; /* We'll start at the first directory entry */ + info_ptr->dir_entry_offset=0; + + /* Find dir_entries_count */ + + info_ptr->dir_entries_count=count_dir_entries (); /* Set the total number of entries */ + + return (1); +} + +struct struct_file_info search_dir_entries (int (*action) (struct struct_file_info *info),int *status) + +/* + This is the main function in this source file. Various actions are implemented using this basic function. + + This routine runs on all directory entries in the current directory. + For each entry, action is called. We'll act according to the return code of action: + + ABORT - Current dir entry is returned. + CONTINUE - Continue searching. + FOUND - Current dir entry is returned. + + If the last entry is reached, it is returned, along with an ABORT status. + + status is updated to the returned code of action. +*/ + +{ + struct struct_file_info info; /* Temporary variables used to */ + struct ext2_dir_entry_2 *dir_entry_ptr; /* contain the current search entries */ + int return_code, next; + + info=first_file_info; /* Start from the first entry - Read it */ + low_read (info.buffer,file_system_info.block_size,info.global_block_offset); + dir_entry_ptr=(struct ext2_dir_entry_2 *) (info.buffer+info.dir_entry_offset); + + while (info.file_offset < info.file_length) { /* While we haven't reached the end */ + + *status=return_code=action (&info); /* Call the client function to test */ + /* the current entry */ + if (return_code==ABORT || return_code==FOUND) + return (info); /* Stop, if so asked */ + + /* Pass to the next entry */ + + dir_entry_ptr=(struct ext2_dir_entry_2 *) (info.buffer+info.dir_entry_offset); + + info.dir_entry_num++; + next = dir_entry_ptr->rec_len; + if (!next) + next = file_system_info.block_size - info.dir_entry_offset; + info.dir_entry_offset += next; + info.file_offset += next; + + if (info.file_offset >= info.file_length) break; + + if (info.dir_entry_offset >= file_system_info.block_size) { /* We crossed a block boundary */ + /* Find the next block, */ + info.block_num++; + info.global_block_num=file_block_to_global_block (info.block_num,&info); + info.global_block_offset=info.global_block_num*file_system_info.block_size; + info.file_offset=info.block_num*file_system_info.block_size; + info.dir_entry_offset=0; + /* read it and update the pointer */ + + low_read (info.buffer,file_system_info.block_size,info.global_block_offset); + dir_entry_ptr=(struct ext2_dir_entry_2 *) (info.buffer+info.dir_entry_offset); + + } + + } + + *status=ABORT;return (info); /* There was no match */ +} + +long count_dir_entries (void) + +/* + +This function counts the number of entries in the directory. We just call search_dir_entries till the end. +The client function is action_count, which just tell search_dir_entries to continue. + +*/ + +{ + int status; + + return (search_dir_entries (&action_count,&status).dir_entry_num); +} + +int action_count (struct struct_file_info *info) + +/* + +Used by count_dir_entries above - This function is called by search_dir_entries, and it tells it to continue +searching, until we get to the last entry. + +*/ + +{ + return (CONTINUE); /* Just continue searching */ +} + +void type_dir___cd (char *command_line) + +/* + Changes to a directory, relative to the current directory. + + This is a complicated operation, so I would repeat here the explanation from the design and + implementation document. + +1. The path is checked that it is not an absolute path (from /). If it is, we let the general cd to do the job by + calling directly type_ext2___cd. + +2. The path is divided into the nearest path and the rest of the path. For example, cd 1/2/3/4 is divided into + 1 and into 2/3/4. + +3. It is the first part of the path that we need to search for in the current directory. We search for it using + search_dir_entries, which accepts the action_name function as the client function. + +4. search_dir_entries will scan the entire entries and will call our action_name function for each entry. + In action_name, the required name will be checked against the name of the current entry, and FOUND will be + returned when a match occurs. + +5. If the required entry is found, we dispatch a remember command to insert the current inode (remember that + type_data is still intact and contains the inode of the current directory) into the object memory. + This is required to easily support symbolic links - If we find later that the inode pointed by the entry is + actually a symbolic link, we'll need to return to this point, and the above inode doesn't have (and can't have, + because of hard links) the information necessary to "move back". + +6. We then dispatch a followinode command to reach the inode pointed by the required entry. This command will + automatically change the type to ext2_inode - We are now at an inode, and all the inode commands are available. + +7. We check the inode's type to see if it is a directory. If it is, we dispatch a dir command to "enter the directory", + and recursively call ourself (The type is dir again) by dispatching a cd command, with the rest of the path + as an argument. + +8. If the inode's type is a symbolic link (only fast symbolic link were meanwhile implemented. I guess this is + typically the case.), we note the path it is pointing at, the saved inode is recalled, we dispatch dir to + get back to the original directory, and we call ourself again with the link path/rest of the path argument. + +9. In any other case, we just stop at the resulting inode. + +*/ + +{ + int status; + char *ptr,full_dir_name [500],dir_name [500],temp [500],temp2 [500]; + struct struct_file_info info; + struct ext2_dir_entry_2 *dir_entry_ptr; + + dir_entry_ptr=(struct ext2_dir_entry_2 *) (file_info.buffer+file_info.dir_entry_offset); + + ptr=parse_word (command_line,dir_name); + + if (*ptr==0) { /* cd alone will enter the highlighted directory */ + strncpy (full_dir_name,dir_entry_ptr->name,dir_entry_ptr->name_len); + full_dir_name [dir_entry_ptr->name_len]=0; + } + else + ptr=parse_word (ptr,full_dir_name); + + ptr=strchr (full_dir_name,'/'); + + if (ptr==full_dir_name) { /* Pathname is from root - Let the general cd do the job */ + sprintf (temp,"cd %s",full_dir_name);type_ext2___cd (temp);return; + } + + if (ptr==NULL) { + strcpy (dir_name,full_dir_name); + full_dir_name [0]=0; + } + + else { + strncpy (dir_name,full_dir_name,ptr-full_dir_name); + dir_name [ptr-full_dir_name]=0; + strcpy (full_dir_name,++ptr); + } + /* dir_name contains the current entry, while */ + /* full_dir_name contains the rest */ + + strcpy (name_search,dir_name); /* name_search is used to hold the required entry name */ + + if (dir_entry_ptr->name_len != strlen (dir_name) || + strncmp (dir_name,dir_entry_ptr->name,dir_entry_ptr->name_len)!=0) + info=search_dir_entries (&action_name,&status); /* Search for the entry. Answer in info. */ + else { + status=FOUND;info=file_info; + } + + if (status==FOUND) { /* If found */ + file_info=info; /* Switch to it, by setting the global file_info */ + dispatch ("remember internal_variable"); /* Move the inode into the objects memory */ + + dispatch ("followinode"); /* Go to the inode pointed by this directory entry */ + + if (S_ISLNK (type_data.u.t_ext2_inode.i_mode)) {/* Symbolic link ? */ + + if (type_data.u.t_ext2_inode.i_size > 60) { /* I'm lazy, I guess :-) */ + wprintw (command_win,"Error - Sorry, Only fast symbolic link following is currently supported\n"); + refresh_command_win (); + return; + } + /* Get the pointed name and append the previous path */ + + strcpy (temp2,(unsigned char *) &type_data.u.t_ext2_inode.i_block); + strcat (temp2,"/"); + strcat (temp2,full_dir_name); + + dispatch ("recall internal_variable"); /* Return to the original inode */ + dispatch ("dir"); /* and to the directory */ + + sprintf (temp,"cd %s",temp2); /* And continue from there by dispatching a cd command */ + dispatch (temp); /* (which can call ourself or the general cd) */ + + return; + } + + if (S_ISDIR (type_data.u.t_ext2_inode.i_mode)) { /* Is it an inode of a directory ? */ + + dispatch ("dir"); /* Yes - Pass to the pointed directory */ + + if (full_dir_name [0] != 0) { /* And call ourself with the rest of the pathname */ + sprintf (temp,"cd %s",full_dir_name); + dispatch (temp); + } + + return; + } + + else { /* If we can't continue from here, we'll just stop */ + wprintw (command_win,"Can\'t continue - Stopping at last inode\n");refresh_command_win (); + return; + } + } + + wprintw (command_win,"Error - Directory entry %s not found.\n",dir_name); /* Hmm, an invalid path somewhere */ + refresh_command_win (); +} + +int action_name (struct struct_file_info *info) + +/* + +Compares the current search entry name (somewhere inside info) with the required name (in name_search). +Returns FOUND if found, or CONTINUE if not found. + +*/ + +{ + struct ext2_dir_entry_2 *dir_entry_ptr; + + dir_entry_ptr=(struct ext2_dir_entry_2 *) (info->buffer+info->dir_entry_offset); + + if (dir_entry_ptr->name_len != strlen (name_search)) + return (CONTINUE); + + if (strncmp (dir_entry_ptr->name,name_search,dir_entry_ptr->name_len)==0) + return (FOUND); + + return (CONTINUE); +} + +void type_dir___entry (char *command_line) + +/* + +Selects a directory entry according to its number. +search_dir_entries is used along with action_entry_num, in the same fashion as the previous usage of search_dir_entries. + +*/ + +{ + int status; + struct struct_file_info info; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - Argument_not_specified\n");wrefresh (command_win); + return; + } + ptr=parse_word (ptr,buffer); + entry_num_search=atol (buffer); + + if (entry_num_search < 0 || entry_num_search >= file_info.dir_entries_count) { + wprintw (command_win,"Error - Entry number out of range\n");wrefresh (command_win); + return; + } + + info=search_dir_entries (&action_entry_num,&status); + if (status==FOUND) { + file_info=info; + dispatch ("show"); + return; + } +#ifdef DEBUG + internal_error ("dir_com","type_dir___entry","According to our gathered data, we should have found this entry"); +#endif +} + +int action_entry_num (struct struct_file_info *info) + +/* + +Used by the above function. Just compares the current number (in info) with the required one. + +*/ + +{ + if (info->dir_entry_num == entry_num_search) + return (FOUND); + + return (CONTINUE); +} + +void type_dir___followinode (char *command_line) + +/* + +Here we pass to the inode pointed by the current entry. +It involves computing the device offset of the inode and using directly the setoffset and settype commands. + +*/ +{ + long inode_offset; + char buffer [80]; + + struct ext2_dir_entry_2 *dir_entry_ptr; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + dir_entry_ptr=(struct ext2_dir_entry_2 *) (file_info.buffer+file_info.dir_entry_offset); + + inode_offset=inode_num_to_inode_offset (dir_entry_ptr->inode); /* Compute the inode's offset */ + sprintf (buffer,"setoffset %ld",inode_offset);dispatch (buffer); /* Move to it */ + sprintf (buffer,"settype ext2_inode");dispatch (buffer); /* and set the type to an inode */ +} + +void type_dir___inode (char *command_line) + +/* + +Returns to the parent inode of the current directory. +This is trivial, as we type_data is still intact and contains the parent inode ! + +*/ + +{ + dispatch ("settype ext2_inode"); +} + + +void type_dir___show (char *command_line) + +/* + +We use search_dir_entries to run on all the entries. Each time, action_show will be called to show one entry. + +*/ + +{ + int status; + + wmove (show_pad,0,0); + show_pad_info.max_line=-1; + + search_dir_entries (&action_show,&status); + show_pad_info.line=file_info.dir_entry_num-show_pad_info.display_lines/2; + refresh_show_pad (); + show_dir_status (); +} + +int action_show (struct struct_file_info *info) + +/* + +Show the current search entry (info) in one line. If the entry happens to be the current edited entry, it is highlighted. + +*/ + +{ + unsigned char temp [80]; + struct ext2_dir_entry_2 *dir_entry_ptr; + + dir_entry_ptr=(struct ext2_dir_entry_2 *) (info->buffer+info->dir_entry_offset); + + if (info->dir_entry_num == file_info.dir_entry_num) /* Highlight the current entry */ + wattrset (show_pad,A_REVERSE); + + strncpy (temp,dir_entry_ptr->name,dir_entry_ptr->name_len); /* The name is not terminated */ + temp [dir_entry_ptr->name_len]=0; + if (dir_entry_ptr->name_len > (COLS - 55) && COLS > 55) + temp [COLS-55]=0; + wprintw (show_pad,"inode = %-8lu rec_len = %-4lu name_len = %-3lu name = %s\n", /* Display the various fields */ + dir_entry_ptr->inode,dir_entry_ptr->rec_len,dir_entry_ptr->name_len,temp); + + show_pad_info.max_line++; + + if (info->dir_entry_num == file_info.dir_entry_num) + wattrset (show_pad,A_NORMAL); + + return (CONTINUE); /* And pass to the next */ +} + +void type_dir___next (char *command_line) + +/* + +This function moves to the next directory entry. It just uses the current information and the entry command. + +*/ + +{ + int offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + sprintf (buffer,"entry %ld",file_info.dir_entry_num+offset);dispatch (buffer); + +} + +void type_dir___prev (char *command_line) + +{ + int offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + sprintf (buffer,"entry %ld",file_info.dir_entry_num-offset);dispatch (buffer); +} + +void show_dir_status (void) + +/* + +Various statistics about the directory. + +*/ + +{ + long inode_num; + + wmove (show_win,0,0); + wprintw (show_win,"Directory listing. Block %ld. ",file_info.global_block_num); + wprintw (show_win,"Directory entry %ld of %ld.\n",file_info.dir_entry_num,file_info.dir_entries_count-1); + wprintw (show_win,"Directory Offset %ld of %ld. ",file_info.file_offset,file_info.file_length-1); + + inode_num=inode_offset_to_inode_num (file_info.inode_offset); + wprintw (show_win,"File inode %ld. Indirection level %ld.\n",inode_num,file_info.level); + + refresh_show_win (); +} + +void type_dir___remember (char *command_line) + +/* + +This is overridden here because we don't remember a directory - It is too complicated. Instead, we remember the +inode of the current directory. + +*/ + +{ + int found=0; + long entry_num; + char *ptr,buffer [80]; + struct struct_descriptor *descriptor_ptr; + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");wrefresh (command_win); + return; + } + + ptr=parse_word (ptr,buffer); + + entry_num=remember_lifo.entries_count++; + if (entry_num>REMEMBER_COUNT-1) { + entry_num=0; + remember_lifo.entries_count--; + } + + descriptor_ptr=first_type; + while (descriptor_ptr!=NULL && !found) { + if (strcmp (descriptor_ptr->name,"ext2_inode")==0) + found=1; + else + descriptor_ptr=descriptor_ptr->next; + } + + + remember_lifo.offset [entry_num]=device_offset; + remember_lifo.type [entry_num]=descriptor_ptr; + strcpy (remember_lifo.name [entry_num],buffer); + + wprintw (command_win,"Object %s in Offset %ld remembered as %s\n",descriptor_ptr->name,device_offset,buffer); + wrefresh (command_win); +} + +void type_dir___set (char *command_line) + +/* + +Since the dir object doesn't have variables, we provide the impression that it has here. ext2_dir_entry was not used +because it is of variable length. + +*/ + +{ + int found=0; + unsigned char *ptr,buffer [80],variable [80],value [80],temp [80]; + struct ext2_dir_entry_2 *dir_entry_ptr; + + dir_entry_ptr=(struct ext2_dir_entry_2 *) (file_info.buffer+file_info.dir_entry_offset); + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - Missing arguments\n");refresh_command_win (); + return; + } + parse_word (ptr,buffer); + ptr=strchr (buffer,'='); + if (ptr==NULL) { + wprintw (command_win,"Error - Bad syntax\n");refresh_command_win ();return; + } + strncpy (variable,buffer,ptr-buffer);variable [ptr-buffer]=0; + strcpy (value,++ptr); + + if (strcasecmp ("inode",variable)==0) { + found=1; + dir_entry_ptr->inode=atol (value); + wprintw (command_win,"Variable %s set to %lu\n",variable,dir_entry_ptr->inode);refresh_command_win (); + + } + + if (strcasecmp ("rec_len",variable)==0) { + found=1; + dir_entry_ptr->rec_len=(unsigned int) atol (value); + wprintw (command_win,"Variable %s set to %lu\n",variable,dir_entry_ptr->rec_len);refresh_command_win (); + + } + + if (strcasecmp ("name_len",variable)==0) { + found=1; + dir_entry_ptr->name_len=(unsigned int) atol (value); + wprintw (command_win,"Variable %s set to %lu\n",variable,dir_entry_ptr->name_len);refresh_command_win (); + + } + + if (strcasecmp ("name",variable)==0) { + found=1; + if (strlen (value) > dir_entry_ptr->name_len) { + wprintw (command_win,"Error - Length of name greater then name_len\n"); + refresh_command_win ();return; + } + strncpy (dir_entry_ptr->name,value,strlen (value)); + wprintw (command_win,"Variable %s set to %s\n",variable,value);refresh_command_win (); + + } + + if (found) { + wattrset (show_pad,A_REVERSE); + strncpy (temp,dir_entry_ptr->name,dir_entry_ptr->name_len); + temp [dir_entry_ptr->name_len]=0; + wmove (show_pad,file_info.dir_entry_num,0); + wprintw (show_pad,"inode = %-8lu rec_len = %-4lu name_len = %-3lu name = %s\n", + dir_entry_ptr->inode,dir_entry_ptr->rec_len,dir_entry_ptr->name_len,temp); + wattrset (show_pad,A_NORMAL); + show_pad_info.line=file_info.dir_entry_num-show_pad_info.display_lines/2; + refresh_show_pad (); + show_dir_status (); + } + + else { + wprintw (command_win,"Error - Variable %s not found\n",variable); + refresh_command_win (); + } + +} + +void type_dir___writedata (char *command_line) + +/* + +We need to override this since the data is not in type_data. Instead, we have to write the buffer which corresponds +to the current block. + +*/ + +{ + low_write (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + return; +} diff --git a/ext2ed/disk.c b/ext2ed/disk.c new file mode 100644 index 0000000..4612d00 --- /dev/null +++ b/ext2ed/disk.c @@ -0,0 +1,239 @@ +/* + +/usr/src/ext2ed/disk.c + +A part of the extended file system 2 disk editor. + +------------------------------------------------- +The filesystem's disk activity pass through here. +------------------------------------------------- + +This file is acting as a filter - Before we pass an actual read or write request to the operating system, we +double check the various permissions and possible errors here. + +The major update which needs to be done here is switching to the use of the llseek system call, so that we will +be able to support ext2 filesystems up to 4 TB. Currently, due to the standard fseek usage, we can't handle +filesystems bigger than 4 GB. The limit is actually 2 GB because I used long rather than unsigned long long at too +many places in the program. To conclude - This upgrade needs to be done carefully; There are many places to change. + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include +#include + +#include "ext2ed.h" + +int write_access; + +int low_read (unsigned char *buffer,unsigned long length,unsigned long offset) + +/* + +This function is used when we need to read something from the filesystem. + +*/ + +{ + +#ifdef DEBUG + + char temp [80]; + + if (device_handle==NULL) { /* Check that a device is indeed open */ + internal_error ("No device opened yet read requested","disk","low_read"); + return (0); + } + if (offset > file_system_info.file_system_size) { /* Check that the offset is within limits */ + sprintf (temp,"Seek offset %ld is out of range",offset); + internal_error (temp,"disk","low_read"); + return (0); + } + +#endif + + if ( (fseek (device_handle,offset,SEEK_SET))==-1) { /* Seek to the required offset */ + wprintw (command_win,"Error - Failed to seek to offset %ld in device %s\n",offset,device_name); + refresh_command_win (); + return (0); + }; + + if ( (fread (buffer,1,length,device_handle))==-1) { /* And do the actual reading */ + wprintw (command_win,"Error - Failed to read from offset %ld in device %s\n",offset,device_name); + refresh_command_win ();return (0); + }; + + return (1); +} + +int low_write (unsigned char *buffer,unsigned long length,unsigned long offset) + +/* + +This is used to change something in the filesystem. +write_access is checked to see if we are allowed to do the actual writing. +As a double safety measure, AllowChanges is rechecked here. +If logging is enabled, we log the change before writing it to the device. + +*/ +{ + char temp [80]; + + if (!write_access) { + wprintw (command_win,"Error - Write access not available (use enablewrite)\n"); + return (0); + } + +#ifdef DEBUG + + if (!AllowChanges) { + internal_error ("AllowChanges=0 yet enablewrite succeeded","disk","low_write"); + return (0); + } + + if (device_handle==NULL) { + internal_error ("No device opened yet read requested","disk","low_write"); + return (0); + } + + if (offset > file_system_info.file_system_size) { + sprintf (temp,"Seek offset %ld is out of range",offset); + internal_error (temp,"disk","low_write"); + return (0); + } + +#endif + + if (LogChanges) + if (!log_changes (buffer,length,offset)) + return (0); + + if ( (fseek (device_handle,offset,SEEK_SET))==-1) { + wprintw (command_win,"Error - Failed to seek to offset %ld in device %s\n",offset,device_name); + refresh_command_win ();return (0); + }; + + + if ( (fwrite (buffer,1,length,device_handle))==-1) { + wprintw (command_win,"Error - Failed to write to offset %ld in device %s\n",offset,device_name); + refresh_command_win ();return (0); + }; + + wprintw (command_win,"Data written");refresh_command_win (); + return (1); +} + +int log_changes (unsigned char *buffer,unsigned long length,unsigned long offset) + +/* + +Log the change in a primitive form - An hex dump of the data before the change and after the change. +The hex bytes are converted to text, so that they will be readable with a standard text editor. + +*/ + +{ + unsigned char *original; + + int i; + time_t current_time; + FILE *fp; + + if ((fp=fopen (LogFile,"a+"))==NULL) { + wprintw (command_win,"Error - Unable to open log file %s\n",LogFile); + refresh_command_win ();return (0); + }; + + current_time=time (NULL); + + fprintf (fp,"\n----- EXT2ED log begin -----\n\n"); + fprintf (fp,"Time: %s\nDevice: %s\n",ctime ((time_t *) ¤t_time),device_name); + fprintf (fp,"Offset: %lu\nLength: %lu\n",offset,length); + + original=(unsigned char *) malloc (length*sizeof (unsigned char)); + + if (original==NULL) { + wprintw (command_win,"Fatal error - Can\'t allocate %lu bytes!"); + refresh_command_win ();fclose (fp);return (0); + } + + if (!low_read (original,length,offset)) { + fclose (fp);return (0); + } + + fprintf (fp,"\nOriginal data:\n\n"); + + for (i=0;iname,"ext2_dir_entry")==0) + current_type->length=type_data.u.t_ext2_dir_entry.rec_len; + + return (1); +} + +int write_type_data (void) + +{ + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n"); + refresh_command_win (); + return (0); + } + + if (device_offset==-1) { + wprintw (command_win,"Error - No offset set\n"); + refresh_command_win (); + return (0); + } + + if (low_write (type_data.u.buffer,file_system_info.block_size,device_offset)==0) + return (0); + + return (1); +} + diff --git a/ext2ed/doc/ext2ed-design.sgml b/ext2ed/doc/ext2ed-design.sgml new file mode 100644 index 0000000..b2cab37 --- /dev/null +++ b/ext2ed/doc/ext2ed-design.sgml @@ -0,0 +1,3459 @@ + + +
+ + + +EXT2ED - The Extended-2 filesystem editor - Design and implementation + +Programmed by Gadi Oxman, with the guide of Avner Lottem + +v0.1, August 3 1995 + + + + +About EXT2ED documentation + + +The EXT2ED documentation consists of three parts: + + + + + + The ext2 filesystem overview. + + + + + + The EXT2ED user's guide. + + + + + + The EXT2ED design and implementation. + + + + + + + + +This document is not the user's guide. If you just intend to use EXT2ED, you +may not want to read it. + + + +However, if you intend to browse and modify the source code, this document is +for you. + + + +In any case, If you intend to read this article, I strongly suggest that you +will be familiar with the material presented in the other two articles as well. + + + + + +Preface + + +In this document I will try to explain how EXT2ED is constructed. +At this time of writing, the initial version is finished and ready +for distribution; It is fully functional. However, this was not always the +case. + + + +At first, I didn't know much about Unix, much less about Unix filesystems, +and even less about Linux and the extended-2 filesystem. While working +on this project, I gradually acquired knowledge about all of the above +subjects. I can think of two ways in which I could have made my project: + + + + + + The "Engineer" way + +Learn the subject thoroughly before I get to the programming itself. +Then, I could easily see the entire picture and select the best +course of action, taking all the factors into account. + + + + + + The "Explorer - Progressive" way. + +Jump immediately into the cold water - Start programming and +learning the material in parallel. + + + + + + + + +I guess that the above dilemma is typical and appears all through science and +technology. + + + +However, I didn't have the luxury of choice when I started my project - +Linux is a relatively new (and great!) operating system. The extended-2 +filesystem is even newer - Its first release lies somewhere in 1993 - Only +passed two years until I started working on my project. + + + +The situation I found myself at the beginning was that I didn't have a fully +detailed document which describes the ext2 filesystem. In fact, I didn't +have any ext2 document at all. When I asked Avner about documentation, he +suggested two references: + + + + + + A general Unix book - THE DESIGN OF THE UNIX OPERATING SYSTEM, by +Maurice J. Bach. + + + + + + The kernel sources. + + + + + +I read the relevant parts of the book before I started my project - It is a +bit old now, but the principles are still the same. However, I needed +more than just the principles. + + + +The kernel sources are a rare bonus! You don't get everyday the full +sources of the operating system. There is so much that can be learned from +them, and it is the ultimate source - The exact answer how the kernel +works is there, with all the fine details. At the first week I started to +look at random at the relevant parts of the sources. However, it is difficult +to understand the global picture from direct reading of over one hundred +page sources. Then, I started to do some programming. I didn't know +yet what I was looking for, and I started to work on the project like a kid +who starts to build a large puzzle. + + + +However, this was exactly the interesting part! It is frustrating to know +it all from advance - I think that the discovery itself, bit by bit, is the +key to a true learning and understanding. + + + +Now, in this document, I am trying to present the subject. Even though I +developed EXT2ED progressively, I now can see the entire subject much +brighter than I did before, and though I do have the option of presenting it +only in the "engineer" way. However, I will not do that. + + + +My presentation will be mixed - Sometimes I will present a subject with an +incremental perspective, and sometimes from a "top down" view. I'll leave +you to decide if my presentation choice was wise :-) + + + +In addition, you'll notice that the sections tend to get shorter as we get +closer to the end. The reason is simply that I started to feel that I was +repeating myself so I decided to present only the new ideas. + + + + + +Getting started ... + + +Getting started is almost always the most difficult task. Once you get +started, things start "running" ... + + + +Before the actual programming + + +From mine talking with Avner, I understood that Linux, like any other Unix +system, provides accesses to the entire disk as though it were a general +file - Accessing the device. It is surely a nice idea. Avner suggested two +ways of action: + + + + + + Opening the device like a regular file in the user space. + + + + + + Constructing a device driver which will run in the kernel space and +provide hooks for the user space program. The advantage is that it +will be a part of the kernel, and would be able to use the ext2 +kernel functions to do some of the work. + + + + + +I chose the first way. I think that the basic reason was simplicity - Learning +the ext2 filesystem was complicated enough, and adding to it the task of +learning how to program in the kernel space was too much. I still don't know +how to program a device driver, and this is perhaps the bad part, but +concerning the project in a back-perspective, I think that the first way is +superior to the second; Ironically, because of the very reason I chose it - +Simplicity. EXT2ED can now run entirely in the user space (which I think is +a point in favor, because it doesn't require the user to recompile its +kernel), and the entire hard work is mine, which fitted nicely into the +learning experience - I didn't use other code to do the job (aside from +looking at the sources, of-course). + + + + + +Jumping into the cold water + + +I didn't know almost anything of the structure of the ext2 filesystem. +Reading the sources was not enough - I needed to experiment. However, a tool +for experiments in the ext2 filesystem was exactly my project! - Kind of a +paradox. + + + +I started immediately with constructing a simple hex editor - It would +open the device as a regular file, provide means of moving inside the +filesystem with a simple offset method, and just show a + hex dump of the contents at this point. Programming this was trivially +simple of-course. At this point, the user-interface didn't matter to me - I +wanted a fast way to interact. As a result, I chose a simple command line +parser. Of course, there where no windows at this point. + + + +A hex editor is nice, but is not enough. It indeed enabled me to see each part +of the filesystem, but the format of the viewed data was difficult to +analyze. I wanted to see the data in a more intuitive way. + + + +At this point of time, the most helpful file in the sources was the ext2 +main include file - /usr/include/linux/ext2_fs.h. Among its contents +there were various structures which I assumed they are disk images - Appear +exactly like that on the disk. + + + +I wanted a quick way to get going. I didn't have the patience to learn +each of the structures use in the code. Rather, I wanted to see them in action, +so that I could explore the connections between them - Test my assumptions, +and reach other assumptions. + + + +So after the hex editor, EXT2ED progressed into a tool which has some +elements of a compiler. I programmed EXT2ED to dynamically read the kernel +ext2 main include file in run time, and process the information. The goal +was to imply a structure-definition on the current offset at the +filesystem. EXT2ED would then display the structure as a list of its +variables names and contents, instead of a meaningless hex dump. + + + +The format of the include file is not very complicated - The structures +are mostly flat - Didn't contain a lot of recursive structure; Only a +global structure definition, and some variables. There were cases of +structures inside structures, I treated them in a somewhat non-elegant way - I +made all the structures flat, and expanded the arrays. As a result, the parser +was very simple. After all, this was not an exercise in compiling, and I +wanted to quickly get some results. + + + +To handle the task, I constructed the struct_descriptor structure. +Each struct_descriptor instance contained information which is needed +in order to format a block of data according to the C structure contained in +the kernel source. The information contained: + + + + + + The descriptor name, used to reference to the structure in EXT2ED. + + + + + + The name of each variable. + + + + + + The relative offset of the each variable in the data block. + + + + + + The length, in bytes, of each variable. + + + + + +Since I didn't want to limit the number of structures, I chose a simple +double linked list to store the information. One variable contained the +current structure type - A pointer to the relevant +struct_descriptor. + + + +Now EXT2ED contained basically three command line operations: + + + + + + setdevice + +Used to open a device for reading only. Write access was postponed +to a very advanced state in the project, simply because I didn't +know a thing of the filesystem structure, and I believed that +making actual changes would do nothing but damage :-) + + + + + + setoffset + +Used to move in the device. + + + + + + settype + +Used to imply a structure definition on the current place. + + + + + + show + +Used to display the data. It displayed the data in a simple hex dump +if there was no type set, or in a nice formatted way - As a list of +the variable contents, if there was. + + + + + + + + +Command line analyzing was primitive back then - A simple switch, as far as +I can remember - Nothing alike the current flow control, but it was enough +at the time. + + + +At the end, I had something to start working with. It knew to format many +structures - None of which I understood - and provided me, without too much +work, something to start with. + + + + + + + +Starting to explore + + +With the above tool in my pocket, I started to explore the ext2 filesystem +structure. From the brief reading in Bach's book, I got familiar to some +basic concepts - The superblock, for example. It seems that the +superblock is an important part of the filesystem. I decided to start +exploring with that. + + + +I realized that the superblock should be at a fixed location in the +filesystem - Probably near the beginning. There can be no other way - +The kernel should start at some place to find it. A brief looking in +the kernel sources revealed that the superblock is signed by a special +signature - A magic number - EXT2_SUPER_MAGIC (0xEF53 - EF probably +stands for Extended Filesystem). I quickly found the superblock at the +fixed offset 1024 in the filesystem - The s_magic variable in the +superblock was set exactly to the above value. + + + +It seems that starting with the superblock was a good bet - Just from +the list of variables, one can learn a lot. I didn't understand all of them +at the time, but it seemed that the following keywords were repeating themselves +in various variables: + + + + + + block + + + + + + inode + + + + + + group + + + + + +At this point, I started to explore the block groups. I will not detail here +the technical design of the ext2 filesystem. I have written a special +article which explains just that, in the "engineering" way. Please refer to it +if you feel that you are lacking knowledge in the structure of the ext2 +filesystem. + + + +I was exploring the filesystem in this way for some time, along with reading +the sources. This lead naturally to the next step. + + + + + +Object specific commands + + +What has become clear is that the above way of exploring is not powerful +enough - I found myself doing various calculations manually in order to pass +between related structures. I needed to replace some tasks with an automated +procedure. + + + +In addition, it also became clear that (of-course) each key object in the +filesystem has its special place in regard to the overall ext2 filesystem +design, and needs a fine tuned handling. It is at this point that the +structure definitions came to life - They became object +definitions, making EXT2ED object oriented. + + + +The actual meaning of the breathtaking words above, is that each structure +now had a list of private commands, which ended up in +calling special fine-tuned C functions. This approach was +found to be very powerful and is the heart of EXT2ED even now. + + + +In order to implement the above concepts, I added the structure +struct_commands. The role of this structure is to group together a +group of commands, which can be later assigned to a specific type. Each +structure had: + + + + + + A list of command names. + + + + + + A list of pointers to functions, which binds each command to its +special fine-tuned C function. + + + + + +In order to relate a list of commands to a type definition, each +struct_descriptor structure (explained earlier) was added a private +struct_commands structure. + + + +Follows the current definitions of struct_descriptor and of +struct_command: + + +struct struct_descriptor { + unsigned long length; + unsigned char name [60]; + unsigned short fields_num; + unsigned char field_names [MAX_FIELDS][80]; + unsigned short field_lengths [MAX_FIELDS]; + unsigned short field_positions [MAX_FIELDS]; + struct struct_commands type_commands; + struct struct_descriptor *prev,*next; +}; + +typedef void (*PF) (char *); + +struct struct_commands { + int last_command; + char *names [MAX_COMMANDS_NUM]; + char *descriptions [MAX_COMMANDS_NUM]; + PF callback [MAX_COMMANDS_NUM]; +}; + + + + + + + + +Program flow control + + +Obviously the above approach lead to a major redesign of EXT2ED. The +main engine of the resulting design is basically the same even now. + + + +I redesigned the program flow control. Up to now, I analyzed the user command +line with the simple switch method. Now I used the far superior callback +method. + + + +I divided the available user commands into two groups: + + + + + + General commands. + + + + + + Type specific commands. + + + + + +As a result, at each point in time, the user was able to enter a +general command, selectable from a list of general commands which was +always available, or a type specific command, selectable from a list of +commands which changed in time according to the current type that the +user was editing. The special type specific command "knew" how to +handle the object in the best possible way - It was "fine tuned" for the +object's place in the ext2 filesystem design. + + + +In order to implement the above idea, I constructed a global variable of +type struct_commands, which contained the general commands. +The type specific commands were accessible through the struct +descriptors, as explained earlier. + + + +The program flow was now done according to the following algorithm: + + + + + + Ask the user for a command line. + + + + + + Analyze the user command - Separate it into command and +arguments. + + + + + + Trace the list of known objects to match the command name to a type. +If the type is found, call the callback function, with the arguments +as a parameter. Then go back to step (1). + + + + + + If the command is not type specific, try to find it in the general +commands, and call it if found. Go back to step (1). + + + + + + If the command is not found, issue a short error message, and return +to step (1). + + + + + +Note the order of the above steps. In particular, note that a command +is first assumed to be a type-specific command and only if this fails, a +general command is searched. The "side-effect" (main effect, actually) +is that when we have two commands with the same name - One that is a +type specific command, and one that is a general command, the dispatching +algorithm will call the type specific command. This allows +overriding of a command to provide fine-tuned operation. +For example, the show command is overridden nearly everywhere, +to accommodate for the different ways in which different objects are displayed, +in order to provide an intuitive fine-tuned display. + + + +The above is done in the dispatch function, in main.c. Since +it is a very important function in EXT2ED, and it is relatively short, I will +list it entirely here. Note that a redesign was made since then - Another +level was added between the two described, but I'll elaborate more on this +later. However, the basic structure follows the explanation described above. + + +int dispatch (char *command_line) + +{ + int i,found=0; + char command [80]; + + parse_word (command_line,command); + + if (strcmp (command,"quit")==0) return (1); + + /* 1. Search for type specific commands FIRST - Allows overriding of a general command */ + + if (current_type != NULL) + for (i=0;i<=current_type->type_commands.last_command && !found;i++) { + if (strcmp (command,current_type->type_commands.names [i])==0) { + (*current_type->type_commands.callback [i]) (command_line); + found=1; + } + } + + /* 2. Now search for ext2 filesystem general commands */ + + if (!found) + for (i=0;i<=ext2_commands.last_command && !found;i++) { + if (strcmp (command,ext2_commands.names [i])==0) { + (*ext2_commands.callback [i]) (command_line); + found=1; + } + } + + + /* 3. If not found, search the general commands */ + + if (!found) + for (i=0;i<=general_commands.last_command && !found;i++) { + if (strcmp (command,general_commands.names [i])==0) { + (*general_commands.callback [i]) (command_line); + found=1; + } + } + + if (!found) { + wprintw (command_win,"Error: Unknown command\n"); + refresh_command_win (); + } + + return (0); +} + + + + + + + +Source files in EXT2ED + + +The project was getting large enough to be split into several source +files. I split the source as much as I could into self-contained +source files. The source files consist of the following blocks: + + + + + + Main include file - ext2ed.h + +This file contains the definitions of the various structures, +variables and functions used in EXT2ED. It is included by all source +files in EXT2ED. + + + + + + + Main block - main.c + +main.c handles the upper level of the program flow control. +It contains the parser and the dispatcher. Its task is +to ask the user for a required action, and to pass control to other +lower level functions in order to do the actual job. + + + + + + + Initialization - init.c + +The init source is responsible for the various initialization +actions which need to be done through the program. For example, +auto detection of an ext2 filesystem when selecting a device and +initialization of the filesystem-specific structures described +earlier. + + + + + + + Disk activity - disk.c + +disk.c is handles the lower level interaction with the +device. All disk activity is passed through this file - The various +functions through the source code request disk actions from the +functions in this file. In this way, for example, we can easily block +the write access to the device. + + + + + + + Display output activity - win.c + +In a similar way to disk.c, the user-interface functions and +most of the interaction with the ncurses library are done +here. Nothing will be actually written to a specific window without +calling a function from this file. + + + + + + + Commands available through dispatching - *_com.c + +The above file name is generic - Each file which ends with +_com.c contains a group of related commands which can be +called through the dispatching function. + +Each object typically has its own file. A separate file is also +available for the general commands. + + + + + +The entire list of source files available at this time is: + + + + + + blockbitmap_com.c + + + + + + dir_com.c + + + + + + disk.c + + + + + + ext2_com.c + + + + + + file_com.c + + + + + + general_com.c + + + + + + group_com.c + + + + + + init.c + + + + + + inode_com.c + + + + + + inodebitmap_com.c + + + + + + main.c + + + + + + super_com.c + + + + + + win.c + + + + + + + + + + +User interface + + +The user interface is text-based only and is based on the following +libraries: + + + + + + + + + The ncurses library, developed by Zeyd Ben-Halim. + + + + + + The GNU readline library. + + + + + + + + +The user interaction is command line based - The user enters a command +line, which consists of a command and of arguments. This fits +nicely with the program flow control described earlier - The command +is used by dispatch to select the right function, and the +arguments are interpreted by the function itself. + + + +The ncurses library + + +The ncurses library enables me to divide the screen into "windows". +The main advantage is that I treat the "window" in a virtual way, asking +the ncurses library to "write to a window". However, the ncurses +library internally buffers the requests, and nothing is actually passed to the +terminal until an explicit refresh is requested. When the refresh request is +made, ncurses compares the current terminal state (as known in the last time +that a refresh was done) with the new to be shown state, and passes to the +terminal the minimal information required to update the display. As a +result, the display output is optimized behind the scenes by the +ncurses library, while I can still treat it in a virtual way. + + + +There are two basic concepts in the ncurses library: + + + + + + A window. + + + + + + A pad. + + + + + +A window can be no bigger than the actual terminal size. A pad, however, is +not limited in its size. + + + +The user screen is divided by EXT2ED into three windows and one pad: + + + + + + Title window. + + + + + + Status window. + + + + + + Main display pad. + + + + + + Command window. + + + + + + + + +The title window is static - It just displays the current version +of EXT2ED. + + + +The user interaction is done in the command window. The user enters a +command line, feedback is usually displayed there, and then relevant +data is usually displayed in the main display and in the status window. + + + +The main display is using a pad instead of a window because +the amount of information which is written to it is not known in advance. +Therefor, the user treats the main display as a "window" into a bigger +display and can scroll vertically using the pgdn and pgup +commands. Although the pad mechanism enables me to use horizontal +scrolling, I have not utilized this. + + + +When I need to show something to the user, I use the ncurses wprintw +command. Then an explicit refresh command is required. As explained before, +the refresh commands is piped through win.c. For example, to update +the command window, refresh_command_win () is used. + + + + + +The readline library + + +Avner suggested me to integrate the GNU readline library in my project. +The readline library is designed specifically for programs which use +command line interface. It provides a nice package of command line editing +tools - Inserting, deleting words, and the whole package of editing tools +which are normally available in the bash shell (Refer to the readline +documentation for details). In addition, I utilized the history +feature of the readline library - The entered commands are saved in a +command history, and can be called later by whatever means that the +readline package provides. Command completion is also supported - When the +user enters a partial command name, EXT2ED will provide the readline library +with the possible completions. + + + + + + + +Possible support of other filesystems + + +The entire ext2 layer is provided through specific objects. Given another +set of objects, support of other filesystem can be provided using the same +dispatching mechanism. In order to prepare the surface for this option, I +added yet another layer to the two-layer structure presented earlier. EXT2ED +commands now consist of three layers: + + + + + + The general commands. + + + + + + The ext2 general commands. + + + + + + The ext2 object specific commands. + + + + + +The general commands are provided by the general_com.c source file, +and are always available. The two other levels are not present when EXT2ED +loads - They are dynamically added by init.c when EXT2ED detects an +ext2 filesystem on the device. + + + +The abstraction levels presented above helps to extend EXT2ED to fully +support a new filesystem, with its own specific type commands. + + + +Even without any source code modification, the user is free to add structure +definitions in a separate file (specified in the configuration file), +which will be added to the list of available objects. The added objects will +consist only of variables, of-course, and will be used through the more +primitive setoffset and settype commands. + + + + + +On the implementation of the various commands + + +This section points out some typical programming style that I used in many +places at the code. + + + +The explicit use of the dispatch function + + +The various commands are reached by the user through the dispatch +function. This is not surprising. The fact that can be surprising, at least in +a first look, is that you'll find the dispatch call in many of my +own functions!. + + + +I am in fact using my own implemented functions to construct higher +level operations. I am heavily using the fact that the dispatching mechanism +is object oriented ant that the overriding principle takes place and +selects the proper function to call when several commands with the same name +are accessible. + + + +Sometimes, however, I call the explicit command directly, without passing +through dispatch. This is typically done when I want to bypass the +overriding effect. + + + + +This is used, for example, in the interaction between the global cd command +and the dir object specific cd command. You will see there that in order +to implement the "entire" cd command, the type specific cd command uses both +a dispatching mechanism to call itself recursively if a relative path is +used, or a direct call of the general cd handling function if an explicit path +is used. + + + + + + +Passing information between handling functions + + +Typically, every source code file which handles one object type has a global +structure specifically designed for it which is used by most of the +functions in that file. This is used to pass information between the various +functions there, and to physically provide the link to other related +objects, typically for initialization use. + + + + +For example, in order to edit a file, information about the +inode is needed - The file command is available only when editing an +inode. When the file command is issued, the handling function (found, +according to the source division outlined above, in inode_com.c) will +store the necessary information about the inode in a specific structure +of type struct_file_info which will be available for use by the file_com.c +functions. Only then it will set the type to file. This is also the reason +that a direct asynchronous set of the object type to a file through a settype +command will fail - The above data structure will not be initialized +properly because the user never was at the inode of the file. + + + + + + +A very simplified overview of a typical command handling function + + +This is a very simplified overview. Detailed information will follow +where appropriate. + + + +The prototype of a typical handling function + + + + + + + + I chose a unified naming convention for the various object +specific commands. It is perhaps best showed with an example: + +The prototype of the handling function of the command next of +the type file is: + + + extern void type_file___next (char *command_line); + + + + +For other types and commands, the words file and next +should be replaced accordingly. + + + + + + + The ext2 general commands syntax is similar. For example, the ext2 +general command super results in calling: + + + extern void type_ext2___super (char *command_line); + + + +Those functions are available in ext2_com.c. + + + + + + The general commands syntax is even simpler - The name of the +handling function is exactly the name of the commands. Those +functions are available in general_com.c. + + + + + + + + + + +"Typical" algorithm + + +This section can't of-course provide meaningful information - Each +command is handled differently, but the following frame is typical: + + + + + + Parse command line arguments and analyze them. Return with an error +message if the syntax is wrong. + + + + + + "Act accordingly", perhaps making use of the global variable available +to this type. + + + + + + Use some dispatch / direct calls in order to pass control to +other lower-level user commands. + + + + + + Sometimes dispatch to the object's show command to +display the resulting data to the user. + + + + + +I told you it is meaningless :-) + + + + + + + + + +Initialization overview + + +In this section I will discuss some aspects of the various initialization +routines available in the source file init.c. + + + +Upon startup + + +Follows the function main, appearing of-course in main.c: + + + +int main (void) + +{ + if (!init ()) return (0); /* Perform some initial initialization */ + /* Quit if failed */ + + parser (); /* Get and parse user commands */ + + prepare_to_close (); /* Do some cleanup */ + printf ("Quitting ...\n"); + return (1); /* And quit */ +} + + + + + +The two initialization functions, which are called by main, are: + + + + + + init + + + + + + prepare_to_close + + + + + + + + +The init function + + +init is called from main upon startup. It initializes the +following tasks / subsystems: + + + + + + Processing of the user configuration file, by using the +process_configuration_file function. Failing to complete the +configuration file processing is considered a fatal error, +and EXT2ED is aborted. I did it this way because the configuration +file has some sensitive user options like write access behavior, and +I wanted to be sure that the user is aware of them. + + + + + + Registration of the general commands through the use of +the add_general_commands function. + + + + + + Reset of the object memory rotating lifo structure. + + + + + + Reset of the device parameters and of the current type. + + + + + + Initialization of the windows subsystem - The interface between the +ncurses library and EXT2ED, through the use of the init_windows +function, available in win.c. + + + + + + Initialization of the interface between the readline library and +EXT2ED, through init_readline. + + + + + + Initialization of the signals subsystem, through +init_signals. + + + + + + Disabling write access. Write access needs to be explicitly enabled +using a user command, to prevent accidental user mistakes. + + + + + +When init is finished, it dispatches the help command in order +to show the available commands to the user. Note that the ext2 layer is still +not added; It will be added if and when EXT2ED will detect an ext2 +filesystem on a device. + + + + + +The prepare_to_close function + + +The prepare_to_close function reverses some of the actions done +earlier in EXT2ED and freeing the dynamically allocated memory. +Specifically, it: + + + + + + Closes the open device, if any. + + + + + + Removes the first level - Removing the general commands, through +the use of free_user_commands, with a pointer to the +general_commands structure as a parameter. + + + + + + Removes of the second level - Removing the ext2 ext2 general +commands, in much the same way. + + + + + + Removes of the third level - Removing the objects and the object +specific commands, by using free_struct_descriptors. + + + + + + Closes the window subsystem, and detaches EXT2ED from the ncurses +library, through the use of the close_windows function, +available in win.c. + + + + + + + + + + + + +Registration of commands + + +Addition of a user command is done through the add_user_command +function. The prototype is: + + +void add_user_command (struct struct_commands *ptr,char *name,char +*description,PF callback); + + +The function receives a pointer to a structure of type +struct_commands, a desired name for the command which will be used by +the user to identify the command, a short description which is utilized by the +help subsystem, and a pointer to a C function which will be called if +dispatch decides that this command was requested. + + + +The add_user_command is a low level function used in the three +levels to add user commands. For example, addition of the ext2 +general commands is done by: + + +void add_ext2_general_commands (void) + +{ + add_user_command (&ext2_commands,"super","Moves to the superblock of the filesystem",type_ext2___super); + add_user_command (&ext2_commands,"group","Moves to the first group descriptor",type_ext2___group); + add_user_command (&ext2_commands,"cd","Moves to the directory specified",type_ext2___cd); +} + + + + + + + +Registration of objects + + +Registration of objects is based, as explained earlier, on the "compilation" +of an external user file, which has a syntax similar to the C language +struct keyword. The primitive parser I have implemented detects the +definition of structures, and calls some lower level functions to actually +register the new detected object. The parser's prototype is: + + +int set_struct_descriptors (char *file_name) + + +It opens the given file name, and calls, when appropriate: + + + + + + add_new_descriptor + + + + + + add_new_variable + + + + + +add_new_descriptor is a low level function which adds a new descriptor +to the doubly linked list of the available objects. It will then call +fill_type_commands, which will add specific commands to the object, +if the object is known. + + + +add_new_variable will add a new variable of the requested length to the +specified descriptor. + + + + + +Initialization upon specification of a device + + +When the general command setdevice is used to open a device, some +initialization sequence takes place, which is intended to determine two +factors: + + + + + + Are we dealing with an ext2 filesystem ? + + + + + + What are the basic filesystem parameters, such as its total size and +its block size ? + + + + + +This questions are answered by the set_file_system_info, possibly +using some help from the user, through the configuration file. +The answers are placed in the file_system_info structure, which is of +type struct_file_system_info: + + +struct struct_file_system_info { + unsigned long file_system_size; + unsigned long super_block_offset; + unsigned long first_group_desc_offset; + unsigned long groups_count; + unsigned long inodes_per_block; + unsigned long blocks_per_group; /* The name is misleading; beware */ + unsigned long no_blocks_in_group; + unsigned short block_size; + struct ext2_super_block super_block; +}; + + + + + +Autodetection of an ext2 filesystem is usually recommended. However, on a damaged +filesystem I can't assure a success. That's were the user comes in - He can +override the auto detection procedure and force an ext2 filesystem, by +selecting the proper options in the configuration file. + + + +If auto detection succeeds, the second question above is automatically +answered - I get all the information I need from the filesystem itself. In +any case, default parameters can be supplied in the configuration file and +the user can select the required behavior. + + + +If we decide to treat the filesystem as an ext2 filesystem, registration of +the ext2 specific objects is done at this point, by calling the +set_struct_descriptors outlined earlier, with the name of the file +which describes the ext2 objects, and is basically based on the ext2 sources +main include file. At this point, EXT2ED can be fully used by the user. + + + +If we do not register the ext2 specific objects, the user can still provide +object definitions in a separate file, and will be able to use EXT2ED in a +limited form, but more sophisticated than a simple hex editor. + + + + + + + +main.c + + +As described earlier, main.c is used as a front-head to the entire +program. main.c contains the following elements: + + + +The main routine + + +The main routine was displayed above. Its task is to pass control to +the initialization routines and to the parser. + + + + + +The parser + + +The parser consists of the following functions: + + + + + + The parser function, which reads the command line from the +user and saves it in readline's history buffer and in the internal +last-command buffer. + + + + + + The parse_word function, which receives a string and parses +the first word from it, ignoring whitespaces, and returns a pointer +to the rest of the string. + + + + + + The complete_command function, which is used by the readline +library for command completion. It scans the available commands at +this point and determines the possible completions. + + + + + + + + + + +The dispatcher + + +The dispatcher was already explained in the flow control section - section +. Its task is to pass control to the proper command +handling function, based on the command line's command. + + + + + +The self-sanity control + + +This is not fully implemented. + + + +The general idea was to provide a control system which will supervise the +internal work of EXT2ED. Since I am pretty sure that bugs exist, I have +double checked myself in a few instances, and issued an internal +error warning if I reached the conclusion that something is not logical. +The internal error is reported by the function internal_error, +available in main.c. + + + +The self sanity check is compiled only if the compile time option +DEBUG is selected. + + + + + + + +The windows interface + + +Screen handling and interfacing to the ncurses library is done in +win.c. + + + +Initialization + + +Opening of the windows is done in init_windows. In +close_windows, we just close our windows. The various window lengths +with an exception to the show pad are defined in the main header file. +The rest of the display will be used by the show pad. + + + + + +Display output + + +Each actual refreshing of the terminal monitor is done by using the +appropriate refresh function from this file: refresh_title_win, +refresh_show_win, refresh_show_pad and +refresh_command_win. + + + +With the exception of the show pad, each function simply calls the +ncurses refresh command. In order to provide to scrolling in +the show pad, some information about its status is constantly updated +by the various functions which display output in it. refresh_show_pad +passes this information to ncurses so that the correct part of the pad +is actually copied to the display. + + + +The above information is saved in a global variable of type struct +struct_pad_info: + + + + + +struct struct_pad_info { + int display_lines,display_cols; + int line,col; + int max_line,max_col; + int disable_output; +}; + + + + + + + +Screen redraw + + +The redraw_all function will just reopen the windows. This action is +necessary if the display gets garbled from some reason. + + + + + + + +The disk interface + + +All the disk activity with regard to the filesystem passes through the file +disk.c. This is done that way to provide additional levels of safety +concerning the disk access. This way, global decisions considering the disk +can be easily accomplished. The benefits of this isolation will become even +clearer in the next sections. + + + +Low level functions + + +Read requests are ultimately handled by low_read and write requests +are handled by low_write. They just receive the length of the data +block, the offset in the filesystem and a pointer to the buffer and pass the +request to the fread or fwrite standard library functions. + + + + + +Mounted filesystems + + +EXT2ED design assumes that the edited filesystem is not mounted. Even if +a reasonably simple way to handle mounted filesystems exists, it is +probably too complicated :-) + + + +Write access to a mounted filesystem will be denied. Read access can be +allowed by using a configuration file option. The mount status is determined +by reading the file /etc/mtab. + + + + + +Write access + + +Write access is the most sensitive part in the program. This program is +intended for editing filesystems. It is obvious that a small mistake +in this regard can make the filesystem not usable anymore. + + + +The following safety measures are added, of-course, to the general Unix +permission protection - The user can always disable write access on the +device file itself. + + + +Considering the user, the following safety measures were taken: + + + + + + The filesystem is never opened with write-access enables. +Rather, the user must explicitly request to enable write-access. + + + + + + The user can disable write access entirely by using a +configuration file option. + + + + + + Changes are never done automatically - Whenever the user makes +changes, they are done in memory. An explicit writedata +command should be issued to make the changes active in the disk. + + + + + +Considering myself, I tried to protect against my bugs by: + + + + + + Opening the device in read-only mode until a write request is +issued by the user. + + + + + + Limiting actual filesystem access to two functions only - +low_read for reading, and low_write for writing. Those +functions were programmed carefully, and I added the self +sanity checks there. In addition, this is the only place in which I +need to check the user options described above - There can be no +place in which I can "forget" to check them. + +Note that The disabling of write-access through the configuration file +is double checked here only as a self-sanity check - If +DEBUG is selected, since write enable should have been refused +and write-access is always disabled at startup, hence finding +here that the user has write access disabled through the +configuration file clearly indicates that I have a bug somewhere. + + + + + + + + +The following safety measure can provide protection against both user +mistakes and my own bugs: + + + + + + I added a logging option, which logs every actual write +access to the disk in the lowest level - In low_write itself. + +The logging has nothing to do with the current type and the various +other higher level operations of EXT2ED - It is simply a hex dump of +the contents which will be overwritten; Both the original contents +and the new written data. + +In that case, even if the user makes a mistake, the original data +can be retrieved. + +Even If I have a bug somewhere which causes incorrect data to be +written to the disk, the logging option will still log exactly the +original contents at the place were data was incorrectly overwritten. +(This assumes, of-course, that low-write and the logging +itself work correctly. I have done my best to verify that this is +indeed the case). + +The logging option is implemented in the log_changes +function. + + + + + + + + + + +Reading / Writing objects + + +Usually (not always), the current object data is available in the +global variable type_data, which is of the type: + + +struct struct_type_data { + long offset_in_block; + + union union_type_data { + char buffer [EXT2_MAX_BLOCK_SIZE]; + struct ext2_acl_header t_ext2_acl_header; + struct ext2_acl_entry t_ext2_acl_entry; + struct ext2_old_group_desc t_ext2_old_group_desc; + struct ext2_group_desc t_ext2_group_desc; + struct ext2_inode t_ext2_inode; + struct ext2_super_block t_ext2_super_block; + struct ext2_dir_entry t_ext2_dir_entry; + } u; +}; + + +The above union enables me, in the program, to treat the data as raw data or +as a meaningful filesystem object. + + + +The reading and writing, if done to this global variable, are done through +the functions load_type_data and write_type_data, available in +disk.c. + + + + + + + +The general commands + + +The general commands are handled in the file general_com.c. + + + +The help system + + +The help command is handled by the function help. The algorithm is as +follows: + + + + + + + + + Check the command line arguments. If there is an argument, pass +control to the detailed_help function, in order to provide +help on the specific command. + + + + + + If general help was requested, display a list of the available +commands at this point. The three levels are displayed in reverse +order - First the commands which are specific to the current type +(If a current type is defined), then the ext2 general commands (If +we decided that the filesystem should be treated like an ext2 +filesystem), then the general commands. + + + + + + Display information about EXT2ED - Current version, general +information about the project, etc. + + + + + + + + + + +The setdevice command + + +The setdevice commands result in calling the set_device +function. The algorithm is: + + + + + + + + + Parse the command line argument. If it isn't available report the +error and return. + + + + + + Close the current open device, if there is one. + + + + + + Open the new device in read-only mode. Update the global variables +device_name and device_handle. + + + + + + Disable write access. + + + + + + Empty the object memory. + + + + + + Unregister the ext2 general commands, using +free_user_commands. + + + + + + Unregister the current objects, using free_struct_descriptors + + + + + + Call set_file_system_info to auto-detect an ext2 filesystem +and set the basic filesystem values. + + + + + + Add the alternate descriptors, supplied by the user. + + + + + + Set the device offset to the filesystem start by dispatching +setoffset 0. + + + + + + Show the new available commands by dispatching the help +command. + + + + + + + + + + +Basic maneuvering + + +Basic maneuvering is done using the setoffset and the settype +user commands. + + + +set_offset accepts some alternative forms of specifying the new +offset. They all ultimately lead to changing the device_offset +global variable and seeking to the new position. set_offset also +calls load_type_data to read a block ahead of the new position into +the type_data global variable. + + + +set_type will point the global variable current_type to the +correct entry in the double linked list of the known objects. If the +requested type is hex or none, current_type will be +initialized to NULL. set_type will also dispatch show, +so that the object data will be re-formatted in the new format. + + + +When editing an ext2 filesystem, it is not intended that those commands will +be used directly, and it is usually not required. My implementation of the +ext2 layer, on the other hand, uses this lower level commands on countless +occasions. + + + + + +The display functions + + +The general command version of show is handled by the show +function. This command is overridden by various objects to provide a display +which is better suited to the object. + + + +The general show command will format the data in type_data according +to the structure definition of the current type and show it on the show +pad. If there is no current type, the data will be shown as a simple hex +dump; Otherwise, the list of variables, along with their values will be shown. + + + +A call to show_info is also made - show_info will provide +general statistics on the show_window, such as the current +block, current type, current offset and current page. + + + +The pgup and pgdn general commands just update the +show_pad_info global variable - We just increment +show_pad_info.line with the number of lines in the screen - +show_pad_info.display_lines, which was initialized in +init_windows. + + + + + +Changing data + + +Data change is done in memory only. An update to the disk if followed by an +explicit writedata command to the disk. The write_data +function simple calls the write_type_data function, outlined earlier. + + + +The set command is used for changing the data. + + + +If there is no current type, control is passed to the hex_set function, +which treats the data as a block of bytes and uses the +type_data.offset_in_block variable to write the new text or hex string +to the correct place in the block. + + + +If a current type is defined, the requested variable is searched in the +current object, and the desired new valued is entered. + + + +The enablewrite commands just sets the global variable +write_access to 1 and re-opens the filesystem in read-write +mode, if possible. + + + +If the current type is NULL, a hex-mode is assumed - The next and +prev commands will just update type_data.offset_in_block. + + + +If the current type is not NULL, the The next and prev command +are usually overridden anyway. If they are not overridden, it will be assumed +that the user is editing an array of such objects, and they will just pass +to the next / prev element by dispatching to setoffset using the +setoffset type + / - X syntax. + + + + + + + +The ext2 general commands + + +The ext2 general commands are contained in the ext2_general_commands +global variable (which is of type struct struct_commands). + + + +The handling functions are implemented in the source file ext2_com.c. +I will include the entire source code since it is relatively short. + + + +The super command + + +The super command just "brings the user" to the main superblock and set the +type to ext2_super_block. The implementation is trivial: + + + + + +void type_ext2___super (char *command_line) + +{ + char buffer [80]; + + super_info.copy_num=0; + sprintf (buffer,"setoffset %ld",file_system_info.super_block_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_super_block");dispatch (buffer); +} + + +It involves only setting the copy_num variable to indicate the main +copy, dispatching a setoffset command to reach the superblock, and +dispatching a settype to enable the superblock specific commands. +This last command will also call the show command of the +ext2_super_block type, through dispatching at the general command +settype. + + + + + +The group command + + +The group command will bring the user to the specified group descriptor in +the main copy of the group descriptors. The type will be set to +ext2_group_desc: + + +void type_ext2___group (char *command_line) + +{ + long group_num=0; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + group_num=atol (buffer); + } + + group_info.copy_num=0;group_info.group_num=0; + sprintf (buffer,"setoffset %ld",file_system_info.first_group_desc_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_group_desc");dispatch (buffer); + sprintf (buffer,"entry %ld",group_num);dispatch (buffer); +} + + +The implementation is as trivial as the super implementation. Note +the use of the entry command, which is a command of the +ext2_group_desc object, to pass to the correct group descriptor. + + + + + +The cd command + + +The cd command performs the usual cd function. The path to the global +cd command is a path from /. + + + +This is one of the best examples of the power of the object oriented +design and of the dispatching mechanism. The operation is complicated, yet the +implementation is surprisingly short! + + + + + +void type_ext2___cd (char *command_line) + +{ + char temp [80],buffer [80],*ptr; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n"); + refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + if (buffer [0] != '/') { + wprintw (command_win,"Error - Use a full pathname (begin with '/')\n"); + refresh_command_win ();return; + } + + dispatch ("super");dispatch ("group");dispatch ("inode"); + dispatch ("next");dispatch ("dir"); + if (buffer [1] != 0) { + sprintf (temp,"cd %s",buffer+1);dispatch (temp); + } +} + + + + + +Note the number of the dispatch calls! + + + +super is used to get to the superblock. group to get to the +first group descriptor. inode brings us to the first inode - The bad +blocks inode. A next is command to pass to the root directory inode, +a dir command "enters" the directory, and then we let the object +specific cd command to take us from there (The object is dir, so +that dispatch will call the cd command of the dir type). +Note that a symbolic link following could bring us back to the root directory, +thus the innocent calls above treats nicely such a recursive case! + + + +I feel that the above is intuitive - I was expressing myself "in the +language" of the ext2 filesystem - (Go to the inode, etc), and the code was +written exactly in this spirit! + + + +I can write more at this point, but I guess I am already a bit carried +away with the self compliments :-) + + + + + + + +The superblock + + +This section details the handling of the superblock. + + + +The superblock variables + + +The superblock object is ext2_super_block. The definition is just +taken from the kernel ext2 main include file - /usr/include/linux/ext2_fs.h. + + + +Those lines of source are copyrighted by Remy Card - The author of the +ext2 filesystem, and by Linus Torvalds - The first author of the Linux +operating system. Please cross reference the section Acknowledgments for the +full copyright. + + + + + + + +struct ext2_super_block { + __u32 s_inodes_count; /* Inodes count */ + __u32 s_blocks_count; /* Blocks count */ + __u32 s_r_blocks_count; /* Reserved blocks count */ + __u32 s_free_blocks_count; /* Free blocks count */ + __u32 s_free_inodes_count; /* Free inodes count */ + __u32 s_first_data_block; /* First Data Block */ + __u32 s_log_block_size; /* Block size */ + __s32 s_log_frag_size; /* Fragment size */ + __u32 s_blocks_per_group; /* # Blocks per group */ + __u32 s_frags_per_group; /* # Fragments per group */ + __u32 s_inodes_per_group; /* # Inodes per group */ + __u32 s_mtime; /* Mount time */ + __u32 s_wtime; /* Write time */ + __u16 s_mnt_count; /* Mount count */ + __s16 s_max_mnt_count; /* Maximal mount count */ + __u16 s_magic; /* Magic signature */ + __u16 s_state; /* File system state */ + __u16 s_errors; /* Behavior when detecting errors */ + __u16 s_pad; + __u32 s_lastcheck; /* time of last check */ + __u32 s_checkinterval; /* max. time between checks */ + __u32 s_creator_os; /* OS */ + __u32 s_rev_level; /* Revision level */ + __u16 s_def_resuid; /* Default uid for reserved blocks */ + __u16 s_def_resgid; /* Default gid for reserved blocks */ + __u32 s_reserved[0]; /* Padding to the end of the block */ + __u32 s_reserved[1]; /* Padding to the end of the block */ + . + . + . + __u32 s_reserved[234]; /* Padding to the end of the block */ +}; + + + + + +Note that I expanded the array due to my primitive parser +implementation. The various fields are described in the technical +document. + + + + + +The superblock commands + + +This section explains the commands available in the ext2_super_block +type. They all appear in super_com.c + + + +The show command + + +The show command is overridden here in order to provide more +information than just the list of variables. A show command will end +up in calling type_super_block___show. + + + +The first thing that we do is calling the general show command in +order to display the list of variables. + + + +We then add some interpretation to the various lines to make the data +somewhat more intuitive (Expansion of the time variables and the creator +operating system code, for example). + + + +We also display the backup copy number of the superblock in the status +window. This copy number is saved in the super_info global variable - +super_info.copy_num. Currently, this is the only variable there ... +but this type of internal variable saving is typical through my +implementation. + + + + + +The backup copies handling commands + + +The current copy number is available in super_info.copy_num. It +was initialized in the ext2 command super, and is used by the various +superblock routines. + + + +The gocopy routine will pass to another copy of the superblock. The +new device offset will be computed with the aid of the variables in the +file_system_info structure. Then the routine will dispatch to +the setoffset and the show routines. + + + +The setactivecopy routine will just save the current superblock data +in a temporary variable of type ext2_super_block, and will dispatch +gocopy 0 to pass to the main superblock. Then it will place the saved +data in place of the actual data. + + + +The above two commands can be used if the main superblock is corrupted. + + + + + + + + + +The group descriptors + + +The group descriptors handling mechanism allows the user to take a tour in +the group descriptors table, stopping at each point, and examining the +relevant inode table, block allocation map or inode allocation map through +dispatching to the relevant objects. + + + +Some information about the group descriptors is available in the global +variable group_info, which is of type struct_group_info: + + + + + +struct struct_group_info { + unsigned long copy_num; + unsigned long group_num; +}; + + + + + +group_num is the index of the current descriptor in the table. + + + +copy_num is the number of the current backup copy. + + + +The group descriptor's variables + + + + +struct ext2_group_desc +{ + __u32 bg_block_bitmap; /* Blocks bitmap block */ + __u32 bg_inode_bitmap; /* Inodes bitmap block */ + __u32 bg_inode_table; /* Inodes table block */ + __u16 bg_free_blocks_count; /* Free blocks count */ + __u16 bg_free_inodes_count; /* Free inodes count */ + __u16 bg_used_dirs_count; /* Directories count */ + __u16 bg_pad; + __u32 bg_reserved[3]; +}; + + + + + +The first three variables are used to provide the links to the +blockbitmap, inodebitmap and inode objects. + + + + + +Movement in the table + + +Movement in the group descriptors table is done using the next, prev and +entry commands. Note that the first two commands override the +general commands of the same name. The next and prev command are just +calling the entry function to do the job. I will show next, +for example: + + + + + +void type_ext2_group_desc___next (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",group_info.group_num+entry_offset); + dispatch (buffer); +} + + +The entry function is also simple - It just calculates the offset +using the information in group_info and in file_system_info, +and uses the usual setoffset / show pair. + + + + + +The show command + + +As usual, the show command is overridden. The implementation is +similar to the superblock's show implementation - We just call the general +show command, and add some information in the status window - The contents of +the group_info structure. + + + + + +Moving between backup copies + + +This is done exactly like the superblock case. Please refer to explanation +there. + + + + + +Links to the available friends + + +From a group descriptor, one typically wants to reach an inode, or +one of the allocation bitmaps. This is done using the inode, +blockbitmap or inodebitmap commands. The implementation is again trivial +- Get the necessary information from the group descriptor, initialize the +structures of the next type, and issue the setoffset / settype pair. + + + +For example, here is the implementation of the blockbitmap command: + + + + + +void type_ext2_group_desc___blockbitmap (char *command_line) + +{ + long block_bitmap_offset; + char buffer [80]; + + block_bitmap_info.entry_num=0; + block_bitmap_info.group_num=group_info.group_num; + + block_bitmap_offset=type_data.u.t_ext2_group_desc.bg_block_bitmap; + sprintf (buffer,"setoffset block %ld",block_bitmap_offset);dispatch (buffer); + sprintf (buffer,"settype block_bitmap");dispatch (buffer); +} + + + + + + + + + +The inode table + + +The inode handling enables the user to move in the inode table, edit the +various attributes of the inode, and follow to the next stage - A file or a +directory. + + + +The inode variables + + + + +struct ext2_inode { + __u16 i_mode; /* File mode */ + __u16 i_uid; /* Owner Uid */ + __u32 i_size; /* Size in bytes */ + __u32 i_atime; /* Access time */ + __u32 i_ctime; /* Creation time */ + __u32 i_mtime; /* Modification time */ + __u32 i_dtime; /* Deletion Time */ + __u16 i_gid; /* Group Id */ + __u16 i_links_count; /* Links count */ + __u32 i_blocks; /* Blocks count */ + __u32 i_flags; /* File flags */ + union { + struct { + __u32 l_i_reserved1; + } linux1; + struct { + __u32 h_i_translator; + } hurd1; + } osd1; /* OS dependent 1 */ + __u32 i_block[EXT2_N_BLOCKS]; /* Pointers to blocks */ + __u32 i_version; /* File version (for NFS) */ + __u32 i_file_acl; /* File ACL */ + __u32 i_size_high; /* High 32bits of size */ + __u32 i_faddr; /* Fragment address */ + union { + struct { + __u8 l_i_frag; /* Fragment number */ + __u8 l_i_fsize; /* Fragment size */ + __u16 i_pad1; + __u32 l_i_reserved2[2]; + } linux2; + struct { + __u8 h_i_frag; /* Fragment number */ + __u8 h_i_fsize; /* Fragment size */ + __u16 h_i_mode_high; + __u16 h_i_uid_high; + __u16 h_i_gid_high; + __u32 h_i_author; + } hurd2; + } osd2; /* OS dependent 2 */ +}; + + + + + +The above is the original source code definition. We can see that the inode +supports Operating systems specific structures. In addition to the +expansion of the arrays, I have "flattened the inode to support only +the Linux declaration. It seemed that this one occasion of multiple +variable aliases didn't justify the complication of generally supporting +aliases. In any case, the above system specific variables are not used +internally by EXT2ED, and the user is free to change the definition in +ext2.descriptors to accommodate for his needs. + + + + + +The handling functions + + +The user interface to movement is the usual next / prev / +entry interface. There is really nothing special in those functions - The +size of the inode is fixed, the total number of inodes is known from the +superblock information, and the current entry can be figured up from the +device offset and the inode table start offset, which is known from the +corresponding group descriptor. Those functions are a bit older then some +other implementations of next and prev, and they do not save +information in a special structure. Rather, they recompute it when +necessary. + + + +The show command is overridden here, and provides a lot of additional +information about the inode - Its type, interpretation of the permissions, +special ext2 attributes (Immutable file, for example), and a lot more. +Again, the general show is called first, and then the additional +information is written. + + + + + +Accessing files and directories + + +From the inode, a file or a directory can typically be reached. +In order to treat a file, for example, its inode needs to be constantly +accessed. To satisfy that need, when editing a file or a directory, the +inode is still saved in memory - type_data is not overwritten. +Rather, the following takes place: + + + + + + An internal global structure which is used by the types file +and dir handling functions is initialized by calling the +appropriate function. + + + + + + The type is changed accordingly. + + + + + +The result is that a settype ext2_inode is the only action necessary +to return to the inode - We actually never left it. + + + +Follows the implementation of the inode's file command: + + + + + +void type_ext2_inode___file (char *command_line) + +{ + char buffer [80]; + + if (!S_ISREG (type_data.u.t_ext2_inode.i_mode)) { + wprintw (command_win,"Error - Inode type is not file\n"); + refresh_command_win (); return; + } + + if (!init_file_info ()) { + wprintw (command_win,"Error - Unable to show file\n"); + refresh_command_win ();return; + } + + sprintf (buffer,"settype file");dispatch (buffer); +} + + + + + +As we can see - We just call init_file_info to get the necessary +information from the inode, and set the type to file. The next call +to show, will dispatch to the file's show implementation. + + + + + + + +Viewing a file + + +There isn't an ext2 kernel structure which corresponds to a file - A file is +just a series of blocks which are determined by its inode. As explained in +the last section, the inode is never actually left - The type is changed to +file - A type which contains no variables, and a special structure is +initialized: + + + + + +struct struct_file_info { + + struct ext2_inodes *inode_ptr; + + long inode_offset; + long global_block_num,global_block_offset; + long block_num,blocks_count; + long file_offset,file_length; + long level; + unsigned char buffer [EXT2_MAX_BLOCK_SIZE]; + long offset_in_block; + + int display; + /* The following is used if the file is a directory */ + + long dir_entry_num,dir_entries_count; + long dir_entry_offset; +}; + + + + + +The inode_ptr will just point to the inode in type_data, which +is not overwritten while the user is editing the file, as the +setoffset command is not internally used. The buffer +will contain the current viewed block of the file. The other variables +contain information about the current place in the file. For example, +global_block_num just contains the current block number. + + + +The general idea is that the above data structure will provide the file +handling functions all the accurate information which is needed to accomplish +their task. + + + +The global structure of the above type, file_info, is initialized by +init_file_info in file_com.c, which is called by the +type_ext2_inode___file function when the user requests to watch the +file. It is updated as necessary to provide accurate information as long as +the file is edited. + + + +Returning to the file's inode + + +Concerning the method I used to handle files, the above task is trivial: + + +void type_file___inode (char *command_line) + +{ + dispatch ("settype ext2_inode"); +} + + + + + + + +File movement + + +EXT2ED keeps track of the current position in the file. Movement inside the +current block is done using next, prev and offset - They just change +file_info.offset_in_block. + + + +Movement between blocks is done using nextblock, prevblock and block. +To accomplish this, the direct blocks, indirect blocks, etc, need to be +traced. This is done by file_block_to_global_block, which accepts a +file's internal block number, and converts it to the actual filesystem block +number. + + + + + +long file_block_to_global_block (long file_block,struct struct_file_info *file_info_ptr) + +{ + long last_direct,last_indirect,last_dindirect; + long f_indirect,s_indirect; + + last_direct=EXT2_NDIR_BLOCKS-1; + last_indirect=last_direct+file_system_info.block_size/4; + last_dindirect=last_indirect+(file_system_info.block_size/4) \ + *(file_system_info.block_size/4); + + if (file_block <= last_direct) { + file_info_ptr->level=0; + return (file_info_ptr->inode_ptr->i_block [file_block]); + } + + if (file_block <= last_indirect) { + file_info_ptr->level=1; + file_block=file_block-last_direct-1; + return (return_indirect (file_info_ptr->inode_ptr-> \ + i_block [EXT2_IND_BLOCK],file_block)); + } + + if (file_block <= last_dindirect) { + file_info_ptr->level=2; + file_block=file_block-last_indirect-1; + return (return_dindirect (file_info_ptr->inode_ptr-> \ + i_block [EXT2_DIND_BLOCK],file_block)); + } + + file_info_ptr->level=3; + file_block=file_block-last_dindirect-1; + return (return_tindirect (file_info_ptr->inode_ptr-> \ + i_block [EXT2_TIND_BLOCK],file_block)); +} + + +last_direct, last_indirect, etc, contain the last internal block number +which is accessed by this method - If the requested block is smaller then +last_direct, for example, it is a direct block. + + + +If the block is a direct block, its number is just taken from the inode. +A non-direct block is handled by return_indirect, return_dindirect and +return_tindirect, which correspond to indirect, double-indirect and +triple-indirect. Each of the above functions is constructed using the lower +level functions. For example, return_dindirect is constructed as +follows: + + + + + +long return_dindirect (long table_block,long block_num) + +{ + long f_indirect; + + f_indirect=block_num/(file_system_info.block_size/4); + f_indirect=return_indirect (table_block,f_indirect); + return (return_indirect (f_indirect,block_num%(file_system_info.block_size/4))); +} + + + + + + + +Object memory + + +The remember command is overridden here and in the dir type - +We just remember the inode of the file. It is just simpler to implement, and +doesn't seem like a big limitation. + + + + + +Changing data + + +The set command is overridden, and provides the same functionality +like the usage of the general set command with no type declared. The +writedata is overridden so that we'll write the edited block +(file_info.buffer) and not type_data (Which contains the inode). + + + + + + + +Directories + + +A directory is just a file which is formatted according to a special format. +As such, EXT2ED handles directories and files quite alike. Specifically, the +same variable of type struct_file_info which is used in the +file, is used here. + + + +The dir type uses all the variables in the above structure, as +opposed to the file type, which didn't use the last ones. + + + +The search_dir_entries function + + +The entire situation is similar to that which was described in the +file type, with one main change: + + + +The main function in dir_com.c is search_dir_entries. This +function will "run" on the entire entries in the directory, and will +call a client's function each time. The client's function is supplied as an +argument, and will check the current entry for a match, based on its own +criterion. It will then signal search_dir_entries whether to +ABORT the search, whether it FOUND the entry it was looking +for, or that the entry is still not found, and we should CONTINUE +searching. Follows the declaration: + + +struct struct_file_info search_dir_entries \ + (int (*action) (struct struct_file_info *info),int *status) + +/* + This routine runs on all directory entries in the current directory. + For each entry, action is called. The return code of action is one of + the following: + + ABORT - Current dir entry is returned. + CONTINUE - Continue searching. + FOUND - Current dir entry is returned. + + If the last entry is reached, it is returned, along with an ABORT status. + + status is updated to the returned code of action. +*/ + + + + + +With the above tool in hand, many operations are simple to perform - Here is +the way I counted the entries in the current directory: + + + + + +long count_dir_entries (void) + +{ + int status; + + return (search_dir_entries (&action_count,&status).dir_entry_num); +} + +int action_count (struct struct_file_info *info) + +{ + return (CONTINUE); +} + + +It will just CONTINUE until the last entry. The returned structure +(of type struct_file_info) will have its number in the +dir_entry_num field, and this is exactly the required number! + + + + + +The cd command + + +The cd command accepts a relative path, and moves there ... +The implementation is of-course a bit more complicated: + + + + + + The path is checked that it is not an absolute path (from /). +If it is, we let the general cd to do the job by calling +directly type_ext2___cd. + + + + + + The path is divided into the nearest path and the rest of the path. +For example, cd 1/2/3/4 is divided into 1 and into +2/3/4. + + + + + + It is the first part of the path that we need to search for in the +current directory. We search for it using search_dir_entries, +which accepts the action_name function as the user defined +function. + + + + + + search_dir_entries will scan the entire entries and will call +our action_name function for each entry. In +action_name, the required name will be checked against the +name of the current entry, and FOUND will be returned when a +match occurs. + + + + + + If the required entry is found, we dispatch a remember +command to insert the current inode into the object memory. +This is required to easily support symbolic links - If we +find later that the inode pointed by the entry is actually a +symbolic link, we'll need to return to this point, and the above +inode doesn't have (and can't have, because of hard links) the +information necessary to "move back". + + + + + + We then dispatch a followinode command to reach the inode +pointed by the required entry. This command will automatically +change the type to ext2_inode - We are now at an inode, and +all the inode commands are available. + + + + + + We check the inode's type to see if it is a directory. If it is, we +dispatch a dir command to "enter the directory", and +recursively call ourself (The type is dir again) by +dispatching a cd command, with the rest of the path as an +argument. + + + + + + If the inode's type is a symbolic link (only fast symbolic link were +meanwhile implemented. I guess this is typically the case.), we note +the path it is pointing at, the saved inode is recalled, we dispatch +dir to get back to the original directory, and we call +ourself again with the link path/rest of the path argument. + + + + + + In any other case, we just stop at the resulting inode. + + + + + + + + + + + + +The block and inode allocation bitmaps + + +The block allocation bitmap is reached by the corresponding group descriptor. +The group descriptor handling functions will save the necessary information +into a structure of the struct_block_bitmap_info type: + + + + + +struct struct_block_bitmap_info { + unsigned long entry_num; + unsigned long group_num; +}; + + + + + +The show command is overridden, and will show the block as a series of +bits, each bit corresponding to a block. The main variable is the +entry_num variable, declared above, which is just the current block +number in this block group. The current entry is highlighted, and the +next, prev and entry commands just change the above variable. + + + +The allocate and deallocate change the specified bits. Nothing +special about them - They just contain code which converts between bit and +byte locations. + + + +The inode allocation bitmap is treated in much the same fashion, with +the same commands available. + + + + + +Filesystem size limitation + + +While an ext2 filesystem has a size limit of 4 TB, EXT2ED currently +can't handle filesystems which are bigger than 2 GB. + + + +This limitation results from my usage of 32 bit long variables and +of the fseek filesystem call, which can't seek up to 4 TB. + + + +By looking in the ext2 library source code by Theodore Ts'o, +I discovered the llseek system call which can seek to a +64 bit unsigned long long offset. Correcting the situation is not +difficult in concept - I need to change long into unsigned long long where +appropriate and modify disk.c to use the llseek system call. + + + +However, fixing the above limitation involves making changes in many places +in the code and will obviously make the entire code less stable. For that +reason, I chose to release EXT2ED as it is now and to postpone the above fix +to the next release. + + + + + +Conclusion + + +Had I known in advance the structure of the ext2 filesystem, I feel that +the resulting design would have been quite different from the presented +design above. + + + +EXT2ED has now two levels of abstraction - A general filesystem, and an +ext2 filesystem, and the surface is more or less prepared for additions +of other filesystems. Had I approached the design in the "engineering" way, +I guess that the first level above would not have existed. + + + + + +Copyright + + +EXT2ED is Copyright (C) 1995 Gadi Oxman. + + + +EXT2ED is hereby placed under the GPL - Gnu Public License. You are free and +welcome to copy, view and modify the sources. My only wish is that my +copyright presented above will be left and that a list of the bug fixes, +added features, etc, will be provided. + + + +The entire EXT2ED project is based, of-course, on the kernel sources. The +ext2.descriptors distributed with EXT2ED is a slightly modified +version of the main ext2 include file, /usr/include/linux/ext2_fs.h. Follows +the original copyright: + + + + + +/* + * linux/include/linux/ext2_fs.h + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/include/linux/minix_fs.h + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + + + + + + + + +Acknowledgments + + +EXT2ED was constructed as a student project in the software +laboratory of the faculty of electrical-engineering in the +Technion - Israel's institute of technology. + + + +At first, I would like to thank Avner Lottem and Doctor Ilana +David for their interest and assistance in this project. + + + +I would also like to thank the following people, who were involved in the +design and implementation of the ext2 filesystem kernel code and support +utilities: + + + + + + Remy Card + +Who designed, implemented and maintains the ext2 filesystem kernel +code, and some of the ext2 utilities. Remy Card is also the +author of several helpful slides concerning the ext2 filesystem. +Specifically, he is the author of File Management in the Linux +Kernel and of The Second Extended File System - Current +State, Future Development. + + + + + + + Wayne Davison + +Who designed the ext2 filesystem. + + + + + + Stephen Tweedie + +Who helped designing the ext2 filesystem kernel code and wrote the +slides Optimizations in File Systems. + + + + + + Theodore Ts'o + +Who is the author of several ext2 utilities and of the ext2 library +libext2fs (which I didn't use, simply because I didn't know +it exists when I started to work on my project). + + + + + + + + +Lastly, I would like to thank, of-course, Linus Torvalds and the +Linux community for providing all of us with such a great operating +system. + + + +Please contact me in a case of bug report, suggestions, or just about +anything concerning EXT2ED. + + + +Enjoy, + + + +Gadi Oxman <tgud@tochnapc2.technion.ac.il> + + + +Haifa, August 95 + + + + +
diff --git a/ext2ed/doc/ext2fs-overview.sgml b/ext2ed/doc/ext2fs-overview.sgml new file mode 100644 index 0000000..0d54f07 --- /dev/null +++ b/ext2ed/doc/ext2fs-overview.sgml @@ -0,0 +1,1569 @@ + + +
+ + + +The extended-2 filesystem overview + +Gadi Oxman, tgud@tochnapc2.technion.ac.il + +v0.1, August 3 1995 + + + + +Preface + + +This document attempts to present an overview of the internal structure of +the ext2 filesystem. It was written in summer 95, while I was working on the +ext2 filesystem editor project (EXT2ED). + + + +In the process of constructing EXT2ED, I acquired knowledge of the various +design aspects of the the ext2 filesystem. This document is a result of an +effort to document this knowledge. + + + +This is only the initial version of this document. It is obviously neither +error-prone nor complete, but at least it provides a starting point. + + + +In the process of learning the subject, I have used the following sources / +tools: + + + + + + Experimenting with EXT2ED, as it was developed. + + + + + + The ext2 kernel sources: + + + + + + The main ext2 include file, +/usr/include/linux/ext2_fs.h + + + + + + The contents of the directory /usr/src/linux/fs/ext2. + + + + + + The VFS layer sources (only a bit). + + + + + + + + + + + The slides: The Second Extended File System, Current State, Future +Development, by Remy Card. + + + + + + The slides: Optimisation in File Systems, by Stephen Tweedie. + + + + + + The various ext2 utilities. + + + + + + + + + + +Introduction + + +The Second Extended File System (Ext2fs) is very popular among Linux +users. If you use Linux, chances are that you are using the ext2 filesystem. + + + +Ext2fs was designed by Remy Card and Wayne Davison. It was +implemented by Remy Card and was further enhanced by Stephen +Tweedie and Theodore Ts'o. + + + +The ext2 filesystem is still under development. I will document here +version 0.5a, which is distributed along with Linux 1.2.x. At this time of +writing, the most recent version of Linux is 1.3.13, and the version of the +ext2 kernel source is 0.5b. A lot of fancy enhancements are planned for the +ext2 filesystem in Linux 1.3, so stay tuned. + + + + + +A filesystem - Why do we need it? + + +I thought that before we dive into the various small details, I'll reserve a +few minutes for the discussion of filesystems from a general point of view. + + + +A filesystem consists of two word - file and system. + + + +Everyone knows the meaning of the word file - A bunch of data put +somewhere. where? This is an important question. I, for example, usually +throw almost everything into a single drawer, and have difficulties finding +something later. + + + +This is where the system comes in - Instead of just throwing the data +to the device, we generalize and construct a system which will +virtualize for us a nice and ordered structure in which we could arrange our +data in much the same way as books are arranged in a library. The purpose of +the filesystem, as I understand it, is to make it easy for us to update and +maintain our data. + + + +Normally, by mounting filesystems, we just use the nice and logical +virtual structure. However, the disk knows nothing about that - The device +driver views the disk as a large continuous paper in which we can write notes +wherever we wish. It is the task of the filesystem management code to store +bookkeeping information which will serve the kernel for showing us the nice +and ordered virtual structure. + + + +In this document, we consider one particular administrative structure - The +Second Extended Filesystem. + + + + + +The Linux VFS layer + + +When Linux was first developed, it supported only one filesystem - The +Minix filesystem. Today, Linux has the ability to support several +filesystems concurrently. This was done by the introduction of another layer +between the kernel and the filesystem code - The Virtual File System (VFS). + + + +The kernel "speaks" with the VFS layer. The VFS layer passes the kernel's +request to the proper filesystem management code. I haven't learned much of +the VFS layer as I didn't need it for the construction of EXT2ED so that I +can't elaborate on it. Just be aware that it exists. + + + + + +About blocks and block groups + + +In order to ease management, the ext2 filesystem logically divides the disk +into small units called blocks. A block is the smallest unit which +can be allocated. Each block in the filesystem can be allocated or +free. + + + +The Ext2fs source code refers to the concept of fragments, which I +believe are supposed to be sub-block allocations. As far as I know, +fragments are currently unsupported in Ext2fs. + + + + +The block size can be selected to be 1024, 2048 or 4096 bytes when creating +the filesystem. + + + +Ext2fs groups together a fixed number of sequential blocks into a group +block. The resulting situation is that the filesystem is managed as a +series of group blocks. This is done in order to keep related information +physically close on the disk and to ease the management task. As a result, +much of the filesystem management reduces to management of a single blocks +group. + + + + + +The view of inodes from the point of view of a blocks group + + +Each file in the filesystem is reserved a special inode. I don't want +to explain inodes now. Rather, I would like to treat it as another resource, +much like a block - Each blocks group contains a limited number of +inode, while any specific inode can be allocated or +unallocated. + + + + + +The group descriptors + + +Each blocks group is accompanied by a group descriptor. The group +descriptor summarizes some necessary information about the specific group +block. Follows the definition of the group descriptor, as defined in +/usr/include/linux/ext2_fs.h: + + + + + +struct ext2_group_desc +{ + __u32 bg_block_bitmap; /* Blocks bitmap block */ + __u32 bg_inode_bitmap; /* Inodes bitmap block */ + __u32 bg_inode_table; /* Inodes table block */ + __u16 bg_free_blocks_count; /* Free blocks count */ + __u16 bg_free_inodes_count; /* Free inodes count */ + __u16 bg_used_dirs_count; /* Directories count */ + __u16 bg_pad; + __u32 bg_reserved[3]; +}; + + + + + +The last three variables: bg_free_blocks_count, bg_free_inodes_count and bg_used_dirs_count provide statistics about the use of the three +resources in a blocks group - The blocks, the inodes and the +directories. I believe that they are used by the kernel for balancing +the load between the various blocks groups. + + + +bg_block_bitmap contains the block number of the block allocation +bitmap block. This is used to allocate / deallocate each block in the +specific blocks group. + + + +bg_inode_bitmap is fully analogous to the previous variable - It +contains the block number of the inode allocation bitmap block, which +is used to allocate / deallocate each specific inode in the filesystem. + + + +bg_inode_table contains the block number of the start of the +inode table of the current blocks group. The inode table is +just the actual inodes which are reserved for the current block. + + + +The block bitmap block, inode bitmap block and the inode table are created +when the filesystem is created. + + + +The group descriptors are placed one after the other. Together they make the +group descriptors table. + + + +Each blocks group contains the entire table of group descriptors in its +second block, right after the superblock. However, only the first copy (in +group 0) is actually used by the kernel. The other copies are there for +backup purposes and can be of use if the main copy gets corrupted. + + + + + +The block bitmap allocation block + + +Each blocks group contains one special block which is actually a map of the +entire blocks in the group, with respect to their allocation status. Each +bit in the block bitmap indicated whether a specific block in the +group is used or free. + + + +The format is actually quite simple - Just view the entire block as a series +of bits. For example, + + + +Suppose the block size is 1024 bytes. As such, there is a place for +1024*8=8192 blocks in a group block. This number is one of the fields in the +filesystem's superblock, which will be explained later. + + + + + + + + + Block 0 in the blocks group is managed by bit 0 of byte 0 in the bitmap +block. + + + + + + Block 7 in the blocks group is managed by bit 7 of byte 0 in the bitmap +block. + + + + + + Block 8 in the blocks group is managed by bit 0 of byte 1 in the bitmap +block. + + + + + + Block 8191 in the blocks group is managed by bit 7 of byte 1023 in the +bitmap block. + + + + + + + + +A value of "1" in the appropriate bit signals that the block is +allocated, while a value of "0" signals that the block is +unallocated. + + + +You will probably notice that typically, all the bits in a byte contain the +same value, making the byte's value 0 or 0ffh. This is done by +the kernel on purpose in order to group related data in physically close +blocks, since the physical device is usually optimized to handle such a close +relationship. + + + + + +The inode allocation bitmap + + +The format of the inode allocation bitmap block is exactly like the format of +the block allocation bitmap block. The explanation above is valid here, with +the work block replaced by inode. Typically, there are much less +inodes then blocks in a blocks group and thus only part of the inode bitmap +block is used. The number of inodes in a blocks group is another variable +which is listed in the superblock. + + + + + +On the inode and the inode tables + + +An inode is a main resource in the ext2 filesystem. It is used for various +purposes, but the main two are: + + + + + + Support of files + + + + + + Support of directories + + + + + + + + +Each file, for example, will allocate one inode from the filesystem +resources. + + + +An ext2 filesystem has a total number of available inodes which is determined +while creating the filesystem. When all the inodes are used, for example, you +will not be able to create an additional file even though there will still +be free blocks on the filesystem. + + + +Each inode takes up 128 bytes in the filesystem. By default, mke2fs +reserves an inode for each 4096 bytes of the filesystem space. + + + +The inodes are placed in several tables, each of which contains the same +number of inodes and is placed at a different blocks group. The goal is to +place inodes and their related files in the same blocks group because of +locality arguments. + + + +The number of inodes in a blocks group is available in the superblock variable +s_inodes_per_group. For example, if there are 2000 inodes per group, +group 0 will contain the inodes 1-2000, group 2 will contain the inodes +2001-4000, and so on. + + + +Each inode table is accessed from the group descriptor of the specific +blocks group which contains the table. + + + +Follows the structure of an inode in Ext2fs: + + + + + +struct ext2_inode { + __u16 i_mode; /* File mode */ + __u16 i_uid; /* Owner Uid */ + __u32 i_size; /* Size in bytes */ + __u32 i_atime; /* Access time */ + __u32 i_ctime; /* Creation time */ + __u32 i_mtime; /* Modification time */ + __u32 i_dtime; /* Deletion Time */ + __u16 i_gid; /* Group Id */ + __u16 i_links_count; /* Links count */ + __u32 i_blocks; /* Blocks count */ + __u32 i_flags; /* File flags */ + union { + struct { + __u32 l_i_reserved1; + } linux1; + struct { + __u32 h_i_translator; + } hurd1; + struct { + __u32 m_i_reserved1; + } masix1; + } osd1; /* OS dependent 1 */ + __u32 i_block[EXT2_N_BLOCKS];/* Pointers to blocks */ + __u32 i_version; /* File version (for NFS) */ + __u32 i_file_acl; /* File ACL */ + __u32 i_size_high; /* High 32bits of size */ + __u32 i_faddr; /* Fragment address */ + union { + struct { + __u8 l_i_frag; /* Fragment number */ + __u8 l_i_fsize; /* Fragment size */ + __u16 i_pad1; + __u32 l_i_reserved2[2]; + } linux2; + struct { + __u8 h_i_frag; /* Fragment number */ + __u8 h_i_fsize; /* Fragment size */ + __u16 h_i_mode_high; + __u16 h_i_uid_high; + __u16 h_i_gid_high; + __u32 h_i_author; + } hurd2; + struct { + __u8 m_i_frag; /* Fragment number */ + __u8 m_i_fsize; /* Fragment size */ + __u16 m_pad1; + __u32 m_i_reserved2[2]; + } masix2; + } osd2; /* OS dependent 2 */ +}; + + + + + +The allocated blocks + + +The basic functionality of an inode is to group together a series of +allocated blocks. There is no limitation on the allocated blocks - Each +block can be allocated to each inode. Nevertheless, block allocation will +usually be done in series to take advantage of the locality principle. + + + +The inode is not always used in that way. I will now explain the allocation +of blocks, assuming that the current inode type indeed refers to a list of +allocated blocks. + + + +It was found experimentally that many of the files in the filesystem are +actually quite small. To take advantage of this effect, the kernel provides +storage of up to 12 block numbers in the inode itself. Those blocks are +called direct blocks. The advantage is that once the kernel has the +inode, it can directly access the file's blocks, without an additional disk +access. Those 12 blocks are directly specified in the variables +i_block[0] to i_block[11]. + + + +i_block[12] is the indirect block - The block pointed by +i_block[12] will not be a data block. Rather, it will just contain a +list of direct blocks. For example, if the block size is 1024 bytes, since +each block number is 4 bytes long, there will be place for 256 indirect +blocks. That is, block 13 till block 268 in the file will be accessed by the +indirect block method. The penalty in this case, compared to the +direct blocks case, is that an additional access to the device is needed - +We need two accesses to reach the required data block. + + + +In much the same way, i_block[13] is the double indirect block +and i_block[14] is the triple indirect block. + + + +i_block[13] points to a block which contains pointers to indirect +blocks. Each one of them is handled in the way described above. + + + +In much the same way, the triple indirect block is just an additional level +of indirection - It will point to a list of double indirect blocks. + + + + + +The i_mode variable + + +The i_mode variable is used to determine the inode type and the +associated permissions. It is best described by representing it as an +octal number. Since it is a 16 bit variable, there will be 6 octal digits. +Those are divided into two parts - The rightmost 4 digits and the leftmost 2 +digits. + + + +The rightmost 4 octal digits + + +The rightmost 4 digits are bit options - Each bit has its own +purpose. + + + +The last 3 digits (Octal digits 0,1 and 2) are just the usual permissions, +in the known form rwxrwxrwx. Digit 2 refers to the user, digit 1 to +the group and digit 2 to everyone else. They are used by the kernel to grant +or deny access to the object presented by this inode. + + + +A smarter permissions control is one of the enhancements planned for +Linux 1.3 - The ACL (Access Control Lists). Actually, from browsing of the +kernel source, some of the ACL handling is already done. + + + + + + + +Bit number 9 signals that the file (I'll refer to the object presented by +the inode as file even though it can be a special device, for example) is +set VTX. I still don't know what is the meaning of "VTX". + + + +Bit number 10 signals that the file is set group id - I don't know +exactly the meaning of the above either. + + + +Bit number 11 signals that the file is set user id, which means that +the file will run with an effective user id root. + + + + + +The leftmost two octal digits + + +Note the the leftmost octal digit can only be 0 or 1, since the total number +of bits is 16. + + + +Those digits, as opposed to the rightmost 4 digits, are not bit mapped +options. They determine the type of the "file" to which the inode belongs: + + + + + + 01 - The file is a FIFO. + + + + + + 02 - The file is a character device. + + + + + + 04 - The file is a directory. + + + + + + 06 - The file is a block device. + + + + + + 10 - The file is a regular file. + + + + + + 12 - The file is a symbolic link. + + + + + + 14 - The file is a socket. + + + + + + + + + + + + +Time and date + + +Linux records the last time in which various operations occurred with the +file. The time and date are saved in the standard C library format - The +number of seconds which passed since 00:00:00 GMT, January 1, 1970. The +following times are recorded: + + + + + + i_ctime - The time in which the inode was last allocated. In +other words, the time in which the file was created. + + + + + + i_mtime - The time in which the file was last modified. + + + + + + i_atime - The time in which the file was last accessed. + + + + + + i_dtime - The time in which the inode was deallocated. In +other words, the time in which the file was deleted. + + + + + + + + + + +i_size + + +i_size contains information about the size of the object presented by +the inode. If the inode corresponds to a regular file, this is just the size +of the file in bytes. In other cases, the interpretation of the variable is +different. + + + + + +User and group id + + +The user and group id of the file are just saved in the variables +i_uid and i_gid. + + + + + +Hard links + + +Later, when we'll discuss the implementation of directories, it will be +explained that each directory entry points to an inode. It is quite +possible that a single inode will be pointed to from several +directories. In that case, we say that there exist hard links to the +file - The file can be accessed from each of the directories. + + + +The kernel keeps track of the number of hard links in the variable +i_links_count. The variable is set to "1" when first allocating the +inode, and is incremented with each additional link. Deletion of a file will +delete the current directory entry and will decrement the number of links. +Only when this number reaches zero, the inode will be actually deallocated. + + + +The name hard link is used to distinguish between the alias method +described above, to another alias method called symbolic linking, +which will be described later. + + + + + +The Ext2fs extended flags + + +The ext2 filesystem associates additional flags with an inode. The extended +attributes are stored in the variable i_flags. i_flags is a 32 +bit variable. Only the 7 rightmost bits are defined. Of them, only 5 bits +are used in version 0.5a of the filesystem. Specifically, the +undelete and the compress features are not implemented, and +are to be introduced in Linux 1.3 development. + + + +The currently available flags are: + + + + + + bit 0 - Secure deletion. + +When this bit is on, the file's blocks are zeroed when the file is +deleted. With this bit off, they will just be left with their +original data when the inode is deallocated. + + + + + + bit 1 - Undelete. + +This bit is not supported yet. It will be used to provide an +undelete feature in future Ext2fs developments. + + + + + + bit 2 - Compress file. + +This bit is also not supported. The plan is to offer "compression on +the fly" in future releases. + + + + + + bit 3 - Synchronous updates. + +With this bit on, the meta-data will be written synchronously to the +disk, as if the filesystem was mounted with the "sync" mount option. + + + + + + bit 4 - Immutable file. + +When this bit is on, the file will stay as it is - Can not be +changed, deleted, renamed, no hard links, etc, before the bit is +cleared. + + + + + + bit 5 - Append only file. + +With this option active, data will only be appended to the file. + + + + + + bit 6 - Do not dump this file. + +I think that this bit is used by the port of dump to linux (ported by +Remy Card) to check if the file should not be dumped. + + + + + + + + + + +Symbolic links + + +The hard links presented above are just another pointers to the same +inode. The important aspect is that the inode number is fixed when +the link is created. This means that the implementation details of the +filesystem are visible to the user - In a pure abstract usage of the +filesystem, the user should not care about inodes. + + + +The above causes several limitations: + + + + + + Hard links can be done only in the same filesystem. This is obvious, +since a hard link is just an inode number in some directory entry, +and the above elements are filesystem specific. + + + + + + You can not "replace" the file which is pointed to by the hard link +after the link creation. "Replacing" the file in one directory will +still leave the original file in the other directory - The +"replacement" will not deallocate the original inode, but rather +allocate another inode for the new version, and the directory entry +at the other place will just point to the old inode number. + + + + + + + + +Symbolic link, on the other hand, is analyzed at run time. A +symbolic link is just a pathname which is accessible from an inode. +As such, it "speaks" in the language of the abstract filesystem. When the +kernel reaches a symbolic link, it will follow it in run time using +its normal way of reaching directories. + + + +As such, symbolic link can be made across different filesystems and a +replacement of a file with a new version will automatically be active on all +its symbolic links. + + + +The disadvantage is that hard link doesn't consume space except to a small +directory entry. Symbolic link, on the other hand, consumes at least an +inode, and can also consume one block. + + + +When the inode is identified as a symbolic link, the kernel needs to find +the path to which it points. + + + +Fast symbolic links + + +When the pathname contains up to 64 bytes, it can be saved directly in the +inode, on the i_block[0] - i_block[15] variables, since those are not +needed in that case. This is called fast symbolic link. It is fast +because the pathname resolution can be done using the inode itself, without +accessing additional blocks. It is also economical, since it allocates only +an inode. The length of the pathname is stored in the i_size +variable. + + + + + +Slow symbolic links + + +Starting from 65 bytes, additional block is allocated (by the use of +i_block[0]) and the pathname is stored in it. It is called slow +because the kernel needs to read additional block to resolve the pathname. +The length is again saved in i_size. + + + + + + + +i_version + + +i_version is used with regard to Network File System. I don't know +its exact use. + + + + + +Reserved variables + + +As far as I know, the variables which are connected to ACL and fragments +are not currently used. They will be supported in future versions. + + + +Ext2fs is being ported to other operating systems. As far as I know, +at least in linux, the os dependent variables are also not used. + + + + + +Special reserved inodes + + +The first ten inodes on the filesystem are special inodes: + + + + + + Inode 1 is the bad blocks inode - I believe that its data +blocks contain a list of the bad blocks in the filesystem, which +should not be allocated. + + + + + + Inode 2 is the root inode - The inode of the root directory. +It is the starting point for reaching a known path in the filesystem. + + + + + + Inode 3 is the acl index inode. Access control lists are +currently not supported by the ext2 filesystem, so I believe this +inode is not used. + + + + + + Inode 4 is the acl data inode. Of course, the above applies +here too. + + + + + + Inode 5 is the boot loader inode. I don't know its +usage. + + + + + + Inode 6 is the undelete directory inode. It is also a +foundation for future enhancements, and is currently not used. + + + + + + Inodes 7-10 are reserved and currently not used. + + + + + + + + + + + + +Directories + + +A directory is implemented in the same way as files are implemented (with +the direct blocks, indirect blocks, etc) - It is just a file which is +formatted with a special format - A list of directory entries. + + + +Follows the definition of a directory entry: + + + + + +struct ext2_dir_entry { + __u32 inode; /* Inode number */ + __u16 rec_len; /* Directory entry length */ + __u16 name_len; /* Name length */ + char name[EXT2_NAME_LEN]; /* File name */ +}; + + + + + +Ext2fs supports file names of varying lengths, up to 255 bytes. The +name field above just contains the file name. Note that it is +not zero terminated; Instead, the variable name_len contains +the length of the file name. + + + +The variable rec_len is provided because the directory entries are +padded with zeroes so that the next entry will be in an offset which is +a multiplication of 4. The resulting directory entry size is stored in +rec_len. If the directory entry is the last in the block, it is +padded with zeroes till the end of the block, and rec_len is updated +accordingly. + + + +The inode variable points to the inode of the above file. + + + +Deletion of directory entries is done by appending of the deleted entry +space to the previous (or next, I am not sure) entry. + + + + + +The superblock + + +The superblock is a block which contains information which describes +the state of the internal filesystem. + + + +The superblock is located at the fixed offset 1024 in the device. Its +length is 1024 bytes also. + + + +The superblock, like the group descriptors, is copied on each blocks group +boundary for backup purposes. However, only the main copy is used by the +kernel. + + + +The superblock contain three types of information: + + + + + + Filesystem parameters which are fixed and which were determined when +this specific filesystem was created. Some of those parameters can +be different in different installations of the ext2 filesystem, but +can not be changed once the filesystem was created. + + + + + + Filesystem parameters which are tunable - Can always be changed. + + + + + + Information about the current filesystem state. + + + + + + + + +Follows the superblock definition: + + + + + +struct ext2_super_block { + __u32 s_inodes_count; /* Inodes count */ + __u32 s_blocks_count; /* Blocks count */ + __u32 s_r_blocks_count; /* Reserved blocks count */ + __u32 s_free_blocks_count; /* Free blocks count */ + __u32 s_free_inodes_count; /* Free inodes count */ + __u32 s_first_data_block; /* First Data Block */ + __u32 s_log_block_size; /* Block size */ + __s32 s_log_frag_size; /* Fragment size */ + __u32 s_blocks_per_group; /* # Blocks per group */ + __u32 s_frags_per_group; /* # Fragments per group */ + __u32 s_inodes_per_group; /* # Inodes per group */ + __u32 s_mtime; /* Mount time */ + __u32 s_wtime; /* Write time */ + __u16 s_mnt_count; /* Mount count */ + __s16 s_max_mnt_count; /* Maximal mount count */ + __u16 s_magic; /* Magic signature */ + __u16 s_state; /* File system state */ + __u16 s_errors; /* Behaviour when detecting errors */ + __u16 s_pad; + __u32 s_lastcheck; /* time of last check */ + __u32 s_checkinterval; /* max. time between checks */ + __u32 s_creator_os; /* OS */ + __u32 s_rev_level; /* Revision level */ + __u16 s_def_resuid; /* Default uid for reserved blocks */ + __u16 s_def_resgid; /* Default gid for reserved blocks */ + __u32 s_reserved[235]; /* Padding to the end of the block */ +}; + + + + + +superblock identification + + +The ext2 filesystem's superblock is identified by the s_magic field. +The current ext2 magic number is 0xEF53. I presume that "EF" means "Extended +Filesystem". In versions of the ext2 filesystem prior to 0.2B, the magic +number was 0xEF51. Those filesystems are not compatible with the current +versions; Specifically, the group descriptors definition is different. I +doubt if there still exists such a installation. + + + + + +Filesystem fixed parameters + + +By using the word fixed, I mean fixed with respect to a particular +installation. Those variables are usually not fixed with respect to +different installations. + + + +The block size is determined by using the s_log_block_size +variable. The block size is 1024*pow (2,s_log_block_size) and should be +between 1024 and 4096. The available options are 1024, 2048 and 4096. + + + +s_inodes_count contains the total number of available inodes. + + + +s_blocks_count contains the total number of available blocks. + + + +s_first_data_block specifies in which of the device block the +superblock is present. The superblock is always present at the fixed +offset 1024, but the device block numbering can differ. For example, if the +block size is 1024, the superblock will be at block 1 with respect to +the device. However, if the block size is 4096, offset 1024 is included in +block 0 of the device, and in that case s_first_data_block +will contain 0. At least this is how I understood this variable. + + + +s_blocks_per_group contains the number of blocks which are grouped +together as a blocks group. + + + +s_inodes_per_group contains the number of inodes available in a group +block. I think that this is always the total number of inodes divided by the +number of blocks groups. + + + +s_creator_os contains a code number which specifies the operating +system which created this specific filesystem: + + + + + + Linux :-) is specified by the value 0. + + + + + + Hurd is specified by the value 1. + + + + + + Masix is specified by the value 2. + + + + + + + + +s_rev_level contains the major version of the ext2 filesystem. +Currently this is always 0, as the most recent version is 0.5B. It +will probably take some time until we reach version 1.0. + + + +As far as I know, fragments (sub-block allocations) are currently not +supported and hence a block is equal to a fragment. As a result, +s_log_frag_size and s_frags_per_group are always equal to +s_log_block_size and s_blocks_per_group, respectively. + + + + + +Ext2fs error handling + + +The ext2 filesystem error handling is based on the following philosophy: + + + + + + Identification of problems is done by the kernel code. + + + + + + The correction task is left to an external utility, such as +e2fsck by Theodore Ts'o for automatic analysis and +correction, or perhaps debugfs by Theodore Ts'o and +EXT2ED by myself, for hand analysis and correction. + + + + + + + + +The s_state variable is used by the kernel to pass the identification +result to third party utilities: + + + + + + bit 0 of s_state is reset when the partition is mounted and +set when the partition is unmounted. Thus, a value of 0 on an +unmounted filesystem means that the filesystem was not unmounted +properly - The filesystem is not "clean" and probably contains +errors. + + + + + + bit 1 of s_state is set by the kernel when it detects an +error in the filesystem. A value of 0 doesn't mean that there isn't +an error in the filesystem, just that the kernel didn't find any. + + + + + + + + +The kernel behavior when an error is found is determined by the user tunable +parameter s_errors: + + + + + + The kernel will ignore the error and continue if s_errors=1. + + + + + + The kernel will remount the filesystem in read-only mode if +s_errors=2. + + + + + + A kernel panic will be issued if s_errors=3. + + + + + + + + +The default behavior is to ignore the error. + + + + + +Additional parameters used by e2fsck + + +Of-course, e2fsck will check the filesystem if errors were detected +or if the filesystem is not clean. + + + +In addition, each time the filesystem is mounted, s_mnt_count is +incremented. When s_mnt_count reaches s_max_mnt_count, e2fsck +will force a check on the filesystem even though it may be clean. It will +then zero s_mnt_count. s_max_mnt_count is a tunable parameter. + + + +E2fsck also records the last time in which the file system was checked in +the s_lastcheck variable. The user tunable parameter +s_checkinterval will contain the number of seconds which are allowed +to pass since s_lastcheck until a check is forced. A value of +0 disables time-based check. + + + + + +Additional user tunable parameters + + +s_r_blocks_count contains the number of disk blocks which are +reserved for root, the user whose id number is s_def_resuid and the +group whose id number is s_deg_resgid. The kernel will refuse to +allocate those last s_r_blocks_count if the user is not one of the +above. This is done so that the filesystem will usually not be 100% full, +since 100% full filesystems can affect various aspects of operation. + + + +s_def_resuid and s_def_resgid contain the id of the user and +of the group who can use the reserved blocks in addition to root. + + + + + +Filesystem current state + + +s_free_blocks_count contains the current number of free blocks +in the filesystem. + + + +s_free_inodes_count contains the current number of free inodes in the +filesystem. + + + +s_mtime contains the time at which the system was last mounted. + + + +s_wtime contains the last time at which something was changed in the +filesystem. + + + + + + + +Copyright + + +This document contains source code which was taken from the Linux ext2 +kernel source code, mainly from /usr/include/linux/ext2_fs.h. Follows +the original copyright: + + + + + +/* + * linux/include/linux/ext2_fs.h + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/include/linux/minix_fs.h + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + + + + + + + + +Acknowledgments + + +I would like to thank the following people, who were involved in the +design and implementation of the ext2 filesystem kernel code and support +utilities: + + + + + + Remy Card + +Who designed, implemented and maintains the ext2 filesystem kernel +code, and some of the ext2 utilities. Remy Card is also the +author of several helpful slides concerning the ext2 filesystem. +Specifically, he is the author of File Management in the Linux +Kernel and of The Second Extended File System - Current +State, Future Development. + + + + + + + Wayne Davison + +Who designed the ext2 filesystem. + + + + + + Stephen Tweedie + +Who helped designing the ext2 filesystem kernel code and wrote the +slides Optimizations in File Systems. + + + + + + Theodore Ts'o + +Who is the author of several ext2 utilities and of the ext2 library +libext2fs (which I didn't use, simply because I didn't know +it exists when I started to work on my project). + + + + + + + + +Lastly, I would like to thank, of-course, Linus Torvalds and the +Linux community for providing all of us with such a great operating +system. + + + +Please contact me in a case of an error report, suggestions, or just about +anything concerning this document. + + + +Enjoy, + + + +Gadi Oxman <tgud@tochnapc2.technion.ac.il> + + + +Haifa, August 95 + + + + +
diff --git a/ext2ed/doc/user-guide.sgml b/ext2ed/doc/user-guide.sgml new file mode 100644 index 0000000..1e8f3cd --- /dev/null +++ b/ext2ed/doc/user-guide.sgml @@ -0,0 +1,2258 @@ + + +
+ + + +EXT2ED - The Extended-2 filesystem editor - User's guide + +Gadi Oxman, tgud@tochnapc2.technion.ac.il + +v0.1, August 3 1995 + + + + +This is only the initial version of this document. It may be unclear at +some places. Please send me feedback with anything regarding to it. + + + + + + + +About EXT2ED documentation + + +The EXT2ED documentation consists of three parts: + + + + + + The ext2 filesystem overview. + + + + + + The EXT2ED user's guide. + + + + + + The EXT2ED design and implementation. + + + + + + + + +If you intend to used EXT2ED, I strongly suggest that you would be familiar +with the material presented in the ext2 filesystem overview as well. + + + +If you also intend to browse and modify the source code, I suggest that you +will also read the article The EXT2ED design and implementation, as it +provides a general overview of the structure of my source code. + + + + + +Introduction + + +EXT2ED is a "disk editor" for the ext2 filesystem. Its purpose is to show +you the internal structures of the ext2 filesystem in an rather intuitive +and logical way, so that it will be easier to "travel" between the various +internal filesystem structures. + + + + + +Basic concepts in EXT2ED + + +Two basic concepts in EXT2ED are commands and types. + + + +EXT2ED is object-oriented in the sense that it defines objects in the +filesystem, like a super-block or a directory. An object is +something which "knows" how to handle some aspect of the filesystem. + + + +Your interaction with EXT2ED is done through commands which EXT2ED +accepts. There are three levels of commands: + + + + + + General Commands + + + + + + Extended-2 Filesystem general commands + + + + + + Type specific commands + + + + + +The General commands are always available. + + + +The ext2 general commands are available only when editing an ext2 filesystem. + + + +The Type specific commands are available when editing a specific object in the +filesystem. Each object typically comes with its own set of internal +variables, and its own set of commands, which are fine tuned handle the +corresponding structure in the filesystem. + + + + + +Running EXT2ED + + +Running EXT2ED is as simple as typing ext2ed from the shell prompt. +There are no command line switches. + + + +When first run, EXT2ED parses its configuration file, ext2ed.conf. +This file must exist. + + + +When the configuration file processing is done, EXT2ED screen should appear +on the screen, with the command prompt ext2ed> displayed. + + + + + +EXT2ED user interface + + +EXT2ED uses the ncurses library for screen management. Your screen +will be divided into four parts, from top to bottom: + + + + + + Title window + + + + + + Status window + + + + + + Main editing window + + + + + + Command window + + + + + +The title window just displays the current version of EXT2ED. + + + +The status window will display various information regarding the state of +the editing at this point. + + + +The main editing window is the place at which the actual data will be shown. +Almost every command will cause some display at this window. This window, as +opposed to the three others, is of variable length - You always look at one +page of it. The current page and the total numbers of pages at this moment +is displayed at the status window. Moving between pages is done by the use +of the pgdn and pgup commands. + + + +The command window is at the bottom of the screen. It always displays a +command prompt ext2ed> and allows you to type a command. Feedback +about the commands entered is displayed to this window also. + + + +EXT2ED uses the readline library while processing a command line. All +the usual editing keys are available. Each entered command is placed into a +history of commands, and can be recalled later. Command Completion is also +supported - Just start to type a command, and press the completion key. + + + +Pressing enter at the command window, without entering a command, +recalls the last command. This is useful when moving between close entries, +in the next command, for example. + + + + + +Getting started + + +A few precautions + + +EXT2ED is a tool for filesystem editing. As such, it can be +dangerous. The summary to the subsections below is that +You must know what you are doing. + + + +A mounted filesystem + + +EXT2ED is not designed to work on a mounted filesystem - It is complicated +enough as it is; I didn't even try to think of handling the various race +conditions. As such, please respect the following advice: + + + +Do not use EXT2ED on a mounted filesystem ! + + + +EXT2ED will not allow write access to a mounted filesystem. Although it is +fairly easy to change EXT2ED so that it will be allowed, I hereby request +again- EXT2ED is not designed for that action, and will most likely corrupt +data if used that way. Please don't do that. + + + +Concerning read access, I chose to leave the decision for the user through +the configuration file option AllowMountedRead. Although read access +on a mounted partition will not do any damage to the filesystem, the data +displayed to you will not be reliable, and showing you incorrect information +may be as bad as corrupting the filesystem. However, you may still wish to +do that. + + + + + +Write access + + +Considering the obvious sensitivity of the subject, I took the following +actions: + + + + + + + + + EXT2ED will always start with a read-only access. Write access mode +needs to be specifically entered by the enablewrite command. +Until this is done, no write will be allowed. Write access can be +disabled at any time with disablewrite. When +enablewrite is issued, the device is reopened in read-write +mode. Needless to say, the device permissions should allow that. + + + + + + As a second level of protection, you can disallow write access in +the configuration file by using the AllowChanges off +configuration option. In this case, the enablewrite command +will be refused. + + + + + + When write access is enabled, the data will never change +immediately. Rather, a specific writedata command is needed +to update the object in the disk with the changed object in memory. + + + + + + In addition, A logging option is provided through the configuration +file options LogChanges and LogFile. With logging +enabled, each change to the disk will be logged at a very primitive +level - A hex dump of the original data and of the new written data. +The log file will be a text file which is easily readable, and you +can make use of it to undo any changes which you made (EXT2ED doesn't +make use of the log file for that purpose, it just logs the changes). + + + + + +Please remember that this is only the initial release of EXT2ED, and it is +not very much tested - It is reasonable to assume that there are +bugs. +However, the logging option above can offer protection even from this +unfortunate case. Therefor, I highly recommend that at least when first +working with EXT2ED, the logging option will be enabled, despite the disk +space which it consumes. + + + + + + + +The help command + + +When loaded, EXT2ED will show a short help screen. This help screen can +always be retrieved by the command help. The help screen displays a +list of all the commands which are available at this point. At startup, only +the General commands are available. +This will change with time, since each object has its own commands. Thus, +commands which are available now may not be available later. +Using help command will display additional information about +the specific command command. + + + + + +The setdevice command + + +The first command that is usually entered to EXT2ED is the setdevice +command. This command simply tells EXT2ED on which device the filesystem is +present. For example, suppose my ext2 filesystem is on the first partition +of my ide disk. The command will be: + + +setdevice /dev/hda1 + + +The following actions will take place in the following order: + + + + + + EXT2ED will check if the partition is mounted. +If the partition is mounted (highly not recommended), +the accept/reject behavior will be decided by the configuration +file. Cross reference section . + + + + + + The specified device will be opened in read-only mode. The +permissions of the device should be set in a way that allows +you to open the device for read access. + + + + + + Autodetection of an ext2 filesystem will be made by searching for +the ext2 magic number in the main superblock. + + + + + + In the case of a successful recognition of an ext2 filesystem, the +ext2 filesystem specific commands and the ext2 specific object +definitions will be registered. The object definitions will be read +at run time from a file specified by the configuration file. + +In case of a corrupted ext2 filesystem, it is quite possible that +the main superblock is damaged and autodetection will fail. In that +case, use the configuration option ForceExt2 on. This is not +the default case since EXT2ED can be used at a lower level to edit a +non-ext2 filesystem. + + + + + + In a case of a successful autodetection, essential information about +the filesystem such as the block size will be read from the +superblock, unless the used overrides this behavior with an +configuration option (not recommended). In that case, the parameters +will be read from the configuration file. + +In a case of an autodetection failure, the essential parameters +will be read from the configuration file. + + + + + +Assuming that you are editing an ext2 filesystem and that everything goes +well, you will notice that additional commands are now available in the help +screen, under the section ext2 filesystem general commands. In +addition, EXT2ED now recognizes a few objects which are essential to the +editing of an ext2 filesystem. + + + + + + + +Two levels of usage + + +Low level usage + + +This section explains what EXT2ED provides even when not editing an ext2 +filesystem. + + + +Even at this level, EXT2ED is more than just a hex editor. It still allows +definition of objects and variables in run time through a user file, +although of-course the objects will not have special fine tuned functions +connected to them. EXT2ED will allow you to move in the filesystem using +setoffset, and to apply an object definition on a specific place +using settype type. From this point and on, the object will +be shown in its native form - You will see a list of the +variables rather than just a hex dump, and you will be able to change each +variable in the intuitive form set variable=value. + + + +To define objects, use the configuration option AlternateDescriptors. + + + +There are now two forms of editing: + + + + + + Editing without a type. In this case, the disk block will be shown +as a text+hex dump, and you will be able to move along and change it. + + + + + + Editing with a type. In this case, the object's variables will be +shown, and you will be able to change each variable in its native form. + + + + + + + + + + +High level usage + + +EXT2ED was designed for the editing of the ext2 filesystem. As such, it +"understands" the filesystem structure to some extent. Each object now has +special fine tuned 'C' functions connected to it, which knows how to display +it in an intuitive form, and how the object fits in the general design of +the ext2 filesystem. It is of-course much easier to use this type of +editing. For example: + + +Issue group 2 to look at the main copy of the third group block +descriptor. With gocopy 1 you can move to its first backup copy, +and with inode you can start editing the inode table of the above +group block. From here, if the inode corresponds to a file, you can +use file to edit the file in a "continuous" way, using +nextblock to pass to its next block, letting EXT2ED following by +itself the direct blocks, indirect blocks, ..., while still preserving the +actual view of the exact block usage of the file. + + +The point is that the "tour" of the filesystem will now be synchronous rather +than asynchronous - Each object has the "links" to pass between connected +logical structures, and special fine-tuned functions to deal with it. + + + + + + + +General commands + + +I will now start with a systematic explanation of the general commands. +Please feel free to experiment, but take care when using the +enablewrite command. + + + +Whenever a command syntax is specified, arguments which are optional are +enclosed with square brackets. + + + +Please note that in EXT2ED, each command can be overridden by a specific +object to provide special fine-tuned functionality. In general, I was +attempting to preserve the similarity between those functions, which are +accessible by the same name. + + + +disablewrite + + + + +Syntax: disablewrite + + +disablewrite is used to reopen the device with read-only access. When +first running EXT2ED, the device is opened in read-only mode, and an +explicit enablewrite is required for write access. When finishing +with changing, a disablewrite is recommended for safety. Cross +reference section . + + + + + +enablewrite + + + + +Syntax: enablewrite + + +enablewrite is used to reopen the device with read-write access. +When first running EXT2ED, the device is opened in read-only mode, and an +explicit enablewrite is required for write access. +enablewrite will fail if write access is disabled from the +configuration file by the AllowChanges off configuration option. +Even after enablewrite, an explicit writedata +is required to actually write the new data to the disk. +When finishing with changing, a disablewrite is recommended for safety. +Cross reference section . + + + + + +help + + + + +Syntax: help [command] + + +The help command is described at section . + + + + + +next + + + + +Syntax: next [number] + + +This section describes the general command next. next +is overridden by several types in EXT2ED, to provide fine-tuned +functionality. + + + +The next general command behavior is depended on whether you are editing a +specific object, or none. + + + + + + + + + In the case where Type is none (The current type is showed +on the status window by the show command), next +passes to the next number bytes in the current edited block. +If number is not specified, number=1 is assumed. + + + + + + In the case where Type is defined, the next commands assumes +that you are editing an array of objects of that type, and the +next command will just pass to the next entry in the array. +If number is defined, it will pass number entries +ahead. + + + + + + + + + + +pgdn + + + + +Syntax: pgdn + + +Usually the edited data doesn't fit into the visible main window. In this +case, the status window will indicate that there is more to see "below" by +the message Page x of y. This means that there are y pages +total, and you are currently viewing the x page. With the pgdn +command, you can pass to the next available page. + + + + + +pgup + + + + +Syntax: pgup + + + + + +pgup is the opposite of pgdn - It will pass to the previous +page. Cross reference section . + + + + + +prev + + + + +Syntax: prev [number] + + + + + +prev is the opposite of next. Cross reference section +. + + + + + +recall + + + + +Syntax: recall object + + +recall is the opposite of remember. It will place you at the +place you where when saving the object position and type information. Cross +reference section . + + + + + +redraw + + + + +Syntax: redraw + + +Sometimes the screen display gets corrupted. I still have problems with +this. The redraw command simply redraws the entire display screen. + + + + + +remember + + + + +Syntax: remember object + + +EXT2ED provides you memory of objects; While editing, you may reach an +object which you will like to return to later. The remember command +will store in memory the current place and type of the object. You can +return to the object by using the recall command. Cross reference +section . + + + +Note: + + + + + + When remembering a file or a directory, the +corresponding inode will be saved in memory. The basic reason is that +the inode is essential for finding the blocks of the file or the +directory. + + + + + + + + + + +set + + + + +Syntax: set [text || hex] arg1 [arg2 arg3 ...] + +or + +Syntax: set variable=value + + +The set command is used to modify the current data. +The set general command behavior is depended on whether you are editing a +specific object, or none. + + + + + + + + + In the case where Type is none, the first syntax should be +used. The set command affects the data starting at the current +highlighted position in the edited block. + + + + + + When using the set hex command, a list of +hexadecimal bytes should follow. + + + + + + When using the set text command, it should be followed +by a text string. + + + + + +Examples: + + + set hex 09 0a 0b 0c 0d 0e 0f + set text Linux is just great ! + + + + + + + + + In the case where Type is defined, the second syntax should be used. +The set commands just sets the variable variable with the +value value. + + + + + +In any case, the data is only changed in memory. For an actual update to the +disk, use the writedata command. + + + + + +setdevice + + + + +Syntax: setdevice device + + +The setdevice command is described at section . + + + + + +setoffset + + + + +Syntax: setoffset [block || type] [+|-]offset + + +The setoffset command is used to move asynchronously inside the file +system. It is considered a low level command, and usually should not be used +when editing an ext2 filesystem, simply because movement is better +utilized through the specific ext2 commands. + + + +The offset is in bytes, and meanwhile should be positive and smaller +than 2GB. + + + +Use of the block modifier changes the counting unit to block. + + + +Use of the + or - modifiers signals that the offset is relative to +the current position. + + + +use of the type modifier is allowed only with relative offset. This +modifier will multiply the offset by the size of the current type. + + + + + +settype + + + + +Syntax: settype type || [none | hex] + + +The settype command is used to move apply the object definitions of +the type type on the current position. It is considered a low level +command and usually should not be used when editing an ext2 filesystem since +EXT2ED provides better tools. It is of-course very useful when editing a +non-ext2 filesystem and using user-defined objects. + + + +When type is hex or none, the data will be displayed as +a hex and text dump. + + + + + +show + + + + +Syntax: show + + +The show command will show the data of the current object at the +current position on the main display window. It will also update the status +window with type specific information. It may be necessary to use +pgdn and pgup to view the entire data. + + + + + +writedata + + + + +Syntax: writedata + + +The writedata command will update the disk with the object data that +is currently in memory. This is the point at which actual change is made to +the filesystem. Without this command, the edited data will not have any +effect. Write access should be allowed for a successful update. + + + + + + + +Editing an ext2 filesystem + + +In order to edit an ext2 filesystem, you should, of course, know the structure +of the ext2 filesystem. If you feel that you lack some knowledge in this +area, I suggest that you do some of the following: + + + + + + Read the supplied ext2 technical information. I tried to summarize +the basic information which is needed to get you started. + + + + + + Get the slides that Remy Card (The author of the ext2 filesystem) +prepared concerning the ext2 filesystem. + + + + + + Read the kernel sources. + + + + + +At this point, you should be familiar with the following terms: +block, inode, superblock, block groups, block allocation bitmap, inode +allocation bitmap, group descriptors, file, directory.Most of the above +are objects in EXT2ED. + + + +When editing an ext2 filesystem it is recommended that you use the ext2 +specific commands, rather then the general commands setoffset and +settype, mainly because: + + + + + + In most cases it will be unreliable, and will display incorrect +information. + +Sometimes in order to edit an object, EXT2ED needs the information +of some other related objects. For example, when editing a +directory, EXT2ED needs access to the inode of the edited directory. +Simply setting the type to a directory will be unreliable, +since the object assumes that you passed through its inode to reach +it, and expects this information, which isn't initialized if you +directly set the type to a directory. + + + + + + EXT2ED offers far better tools for handling the ext2 filesystem +using the ext2 specific commands. + + + + + + + + + + +ext2 general commands + + +The ext2 general commands are available only when you are editing an +ext2 filesystem. They are general in the sense that they are not +specific to some object, and can be invoked anytime. + + + +super + + + + +Syntax: super + + +The super command will "bring you" to the main superblock copy. It +will automatically set the object type to ext2_super_block. Then you +will be able to view and edit the superblock. When you are in the +superblock, other commands will be available. + + + + + +group + + + + +Syntax: group [number] + + +The group command will "bring you" to the main copy of the +number group descriptor. It will automatically set the object type to +ext2_group_desc. Then you will be able to view and edit the group +descriptor entry. When you are there, other commands will be available. + + + + + +cd + + + + +Syntax: cd path + + +The cd command will let you travel in the filesystem in the nice way +that the mounted filesystem would have let you. + + + +The cd command is a complicated command. Although it may sound +simple at first, an implementation of a typical cd requires passing through +the group descriptors, inodes, directory entries, etc. For example: + + + +The innocent cd /usr command can be done by using more primitive +EXT2ED commands in the following way (It is implemented exactly this way): + + + + + + Using group 0 to go to the first group descriptor. + + + + + + Using inode to get to the Bad blocks inode. + + + + + + Using next to pass to the root directory inode. + + + + + + Using dir to see the directory. + + + + + + Using next until we find the directory usr. + + + + + + Using followinode to pass to the inode corresponding to usr. + + + + + + Using dir to see the directory of /usr. + + + + + +And those commands aren't that primitive; For example, the tracing of the +blocks which belong to the root directory is done automatically by the dir +command behind the scenes, and the followinode command will automatically +"run" to the correct group descriptor in order to find the required inode. + + + +The path to the general cd command needs to be a full pathname - +Starting from /. The cd command stops at the last reachable +point, which can be a directory entry, in which case the type will be set to +dir, or an inode, in which case the type will be set to +ext2_inode. Symbolic links (Only fast symbolic links, meanwhile) are +automatically followed (if they are not across filesystems, of-course). If +the type is set to dir, you can use a path relative to the +"current directory". + + + + + + + +The superblock + + +The superblock can always be reached by the ext2 general command +super. Cross reference section . + + + +The status window will show you which copy of the superblock copies you are +currently editing. + + + +The main data window will show you the values of the various superblock +variables, along with some interpretation of the values. + + + +Data can be changed with the set and writedata commands. + + +For example, set s_r_blocks_count=1400 will reserve 1400 blocks for root. + + + + + +gocopy + + + + +Syntax: gocopy number + + +The gocopy command will "bring you" to the backup copy number +of the superblock copies. gocopy 0, for example, will bring you to +the main copy. + + + + + +setactivecopy + + + + +Syntax: setactivecopy + + +The setactivecopy command will copy the contents of the current +superblock copy onto the contents of the main copy. It will also switch to +editing of the main copy. No actual data is written to disk, of-course, +until you issue the writedata command. + + + + + + + +The group descriptors + + +The group descriptors can be edited by the group command. + + + +The status window will indicate the current group descriptor, the total +number of group descriptors (and hence of group blocks), and the backup copy +number. + + + +The main data window will just show you the values of the various variables. + + + +Basically, you can use the next and prev commands, along with the +set command, to modify the group descriptors. + + + +The group descriptors object is a junction, from which you can reach: + + + + + + The inode table of the corresponding block group (the inode +command) + + + + + + The block allocation bitmap (the blockbitmap command) + + + + + + The inode allocation bitmap (the inodebitmap command) + + + + + + + + +blockbitmap + + + + +Syntax: blockbitmap + + +The blockbitmap command will let you edit the block bitmap allocation +block of the current group block. + + + + + +entry + + + + +Syntax: entry number + + +The entry command will move you to the number group descriptor in the +group descriptors table. + + + + + +inode + + + + +Syntax: inode + + +The inode command will pass you to the first inode in the current +group block. + + + + + +inodebitmap + + + + +Syntax: inodebitmap + + +The inodebitmap command will let you edit the inode bitmap allocation +block of the current group block. + + + + + +next + + + + +Syntax: next [number] + + +The next command will pass to the next number group +descriptor. If number is omitted, number=1 is assumed. + + + + + +prev + + + + +Syntax: prev [number] + + +The prev command will pass to the previous number group +descriptor. If number is omitted, number=1 is assumed. + + + + + +setactivecopy + + + + +Syntax: setactivecopy + + +The setactivecopy command copies the contents of the current group +descriptor, to its main copy. The updated main copy will then be shown. No +actual change is made to the disk until you issue the writedata +command. + + + + + + + +The inode + + +An inode can be reached by the following two ways: + + + + + + Using inode from the corresponding group descriptor. + + + + + + Using followinode from a directory entry. + + + + + + Using the cd command with the pathname to the file. + +For example, cd /usr/src/ext2ed/ext2ed.h + + + + + + + + +The status window will indicate: + + + + + + The current global inode number. + + + + + + The total total number of inodes. + + + + + + On which block group the inode is allocated. + + + + + + The total number of inodes in this group block. + + + + + + The index of the current inode in the current group block. + + + + + + The type of the inode (file, directory, special, etc). + + + + + + + + +The main data window, in addition to the list of variables, will contain +some interpretations on the right side. + + + +If the inode corresponds to a file, you can use the file command to +edit the file. + + + +If the inode is an inode of a directory, you can use the dir command +to edit the directory. + + + +dir + + + + +Syntax: dir + + +If the inode mode corresponds to a directory (shown on the status window), +you can enter directory mode editing by using dir. + + + + + +entry + + + + +Syntax: entry number + + +The entry command will move you to the number inode in the +current inode table. + + + + + +file + + + + +Syntax: file + + +If the inode mode corresponds to a file (shown on the status window), +you can enter file mode editing by using file. + + + + + +group + + + + +Syntax: group + + +The group command is used to go to the group descriptor of the +current group block. + + + + + +next + + + + +Syntax: next [number] + + +The next command will pass to the next number inode. +If number is omitted, number=1 is assumed. + + + + + +prev + + + + +Syntax: prev [number] + + +The prev command will pass to the previous number inode. +If number is omitted, number=1 is assumed. + + + + + + + +The file + + +When editing a file, EXT2ED offers you a both a continuous and a true +fragmented view of the file - The file is still shown block by block with +the true block number at each stage and EXT2ED offers you commands which +allow you to move between the file blocks, while finding the +allocated blocks by using the inode information behind the scenes. + + + +Aside from this, the editing is just a hex editing - You move the +cursor in the current block of the file by using next and +prev, move between blocks by nextblock and prevblock, +and make changes by the set command. Note that the set command is +overridden here - There are no variables. The writedata command will +update the current block to the disk. + + + +Reaching a file can be done by using the file command from its inode. +The inode can be reached by any other means, for example, by the +cd command, if you know the file name. + + + +The status window will indicate: + + + + + + The global block number. + + + + + + The internal file block number. + + + + + + The file offset. + + + + + + The file size. + + + + + + The file inode number. + + + + + + The indirection level - Whether it is a direct block (0), indirect +(1), etc. + + + + + + + + +The main data window will display the file either in hex mode or in text +mode, select-able by the display command. + + + +In hex mode, EXT2ED will display offsets in the current block, along with a +text and hex dump of the current block. + + + +In either case the current place will be highlighted. In the hex mode +it will be always highlighted, while in the text mode it will be highlighted +if the character is display-able. + + + +block + + + + +Syntax: block block_num + + +The block command is used to move inside the file. The +block_num argument is the requested internal file block number. A +value of 0 will reach the beginning of the file. + + + + + +display + + + + +Syntax: display [text || hex] + + +The display command changes the display mode of the file. +display +hex will switch to hex mode, while display text will switch +to text mode. The default mode when no display command is issued is +hex mode. + + + + + +inode + + + + +Syntax: inode + + +The inode command will return to the inode of the current file. + + + + + +next + + + + +Syntax: next [num] + + +The next command will pass to the next byte in the file. If +num is supplied, it will pass to the next num bytes. + + + + + +nextblock + + + + +Syntax: nextblock [num] + + +The nextblock command will pass to the next block in the file. If +num is supplied, it will pass to the next num blocks. + + + + + +prev + + + + +Syntax: prev [num] + + +The prev command will pass to the previous byte in the file. If +num is supplied, it will pass to the previous num bytes. + + + + + +prevblock + + + + +Syntax: prevblock [num] + + +The nextblock command will pass to the previous block in the file. If +num is supplied, it will pass to the previous num blocks. + + + + + +offset + + + + +Syntax: offset file_offset + + +The offset command will move to the specified offset in the file. + + + + + +set + + + + +Syntax: set [text || hex] arg1 [arg2 arg3 ...] + + +The file set command is working like the general set command, +with type=none. There are no variables. + + + + + +writedata + + + + +Syntax: writedata + + +The writedata command will update the current file block in the disk. + + + + + + + +The directory + + +When editing a file, EXT2ED analyzes for you both the allocation blocks of +the directory entries, and the directory entries. + + + +Each directory entry is displayed on one row. You can move the highlighted +entry with the usual next and prev commands, and "dive in" +with the followinode command. + + + +The status window will indicate: + + + + + + The directory entry number. + + + + + + The total number of directory entries in this directory. + + + + + + The current global block number. + + + + + + The current offset in the entire directory - When viewing the +directory as a continuous file. + + + + + + The inode number of the directory itself. + + + + + + The indirection level - Whether it is a direct block (0), indirect +(1), etc. + + + + + + + + +cd + + + + +Syntax: cd [path] + + +The cd command is used in the usual meaning, like the global cd +command. + + + + + + If path is not specified, the current directory entry is +followed. + + + + + + path can be relative to the current directory. + + + + + + path can also end up in a file, in which case the file inode +will be reached. + + + + + + Symbolic link (fast only, meanwhile) is automatically followed. + + + + + + + + + + +entry + + + + +Syntax: entry [entry_num] + + +The entry command sets entry_num as the current directory +entry. + + + + + +followinode + + + + +Syntax: followinode + + +The followinode command will move you to the inode pointed by the +current directory entry. + + + + + +inode + + + + +Syntax: inode + + +The inode command will return you to the parent inode of the whole +directory listing. + + + + + +next + + + + +Syntax: next [num] + + +The next command will pass to the next directory entry. +If num is supplied, it will pass to the next num entries. + + + + + +prev + + + + +Syntax: prev [num] + + +The prev command will pass to the previous directory entry. +If num is supplied, it will pass to the previous num entries. + + + + + +writedata + + + + +Syntax: writedata + + +The writedata command will write the current directory entry to the +disk. + + + + + + + +The block allocation bitmap + + +The block allocation bitmap of any block group can be reached from +the corresponding group descriptor. + + + +You will be offered a bit listing of the entire blocks in the group. The +current block will be highlighted and its number will be displayed in the +status window. + + + +A value of "1" means that the block is allocated, while a value of "0" +signals that it is free. The value is also interpreted in the status +window. You can use the usual next/prev commands, along with the +allocate/deallocate commands. + + + +allocate + + + + +Syntax: allocate [num] + + +The allocate command allocates num blocks, starting from the +highlighted position. If num is not specified, num=1 is assumed. +Of-course, no actual change is made until you issue a writedata command. + + + + + +deallocate + + + + +Syntax: deallocate [num] + + +The deallocate command deallocates num blocks, starting from the +highlighted position. If num is not specified, num=1 is assumed. +Of-course, no actual change is made until you issue a writedata command. + + + + + +entry + + + + +Syntax: entry [entry_num] + + +The entry command sets the current highlighted block to +entry_num. + + + + + +next + + + + +Syntax: next [num] + + +The next command will pass to the next bit, which corresponds to the +next block. If num is supplied, it will pass to the next num +bits. + + + + + +prev + + + + +Syntax: prev [num] + + +The prev command will pass to the previous bit, which corresponds to the +previous block. If num is supplied, it will pass to the previous +num bits. + + + + + + + +The inode allocation bitmap + + +The inode allocation bitmap is very similar to the block allocation +bitmap explained above. It is also reached from the corresponding group +descriptor. Please refer to section . + + + + + +Filesystem size limitation + + +While an ext2 filesystem has a size limit of 4 TB, EXT2ED currently +can't handle filesystems which are bigger than 2 GB. + + + +I am sorry for the inconvenience. This will hopefully be fixed in future +releases. + + + + + +Copyright + + +EXT2ED is Copyright (C) 1995 Gadi Oxman. + + + +EXT2ED is hereby placed under the GPL - Gnu Public License. You are free and +welcome to copy, view and modify the sources. My only wish is that my +copyright presented above will be left and that a list of the bug fixes, +added features, etc, will be provided. + + + +The entire EXT2ED project is based, of-course, on the kernel sources. The +ext2.descriptors distributed with EXT2ED is a slightly modified +version of the main ext2 include file, /usr/include/linux/ext2_fs.h. Follows +the original copyright: + + + + + +/* + * linux/include/linux/ext2_fs.h + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/include/linux/minix_fs.h + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + + + + + + + + +Acknowledgments + + +EXT2ED was constructed as a student project in the software +laboratory of the faculty of electrical-engineering in the +Technion - Israel's institute of technology. + + + +At first, I would like to thank Avner Lottem and Doctor Ilana David for their interest and assistance in this project. + + + +I would also like to thank the following people, who were involved in the +design and implementation of the ext2 filesystem kernel code and support +utilities: + + + + + +Remy Card + +Who designed, implemented and maintains the ext2 filesystem kernel +code, and some of the ext2 utilities. Remy Card is also the author +of several helpful slides concerning the ext2 filesystem. +Specifically, he is the author of File Management in the Linux +Kernel and of The Second Extended File System - Current State, +Future Development. + + + + + + +Wayne Davison + +Who designed the ext2 filesystem. + + + + + +Stephen Tweedie + +Who helped designing the ext2 filesystem kernel code and wrote the +slides Optimizations in File Systems. + + + + + +Theodore Ts'o + +Who is the author of several ext2 utilities and of the ext2 library +libext2fs (which I didn't use, simply because I didn't know +it exists when I started to work on my project). + + + + + + + + +Lastly, I would like to thank, of-course, Linus Torvalds and the +Linux community for providing all of us with such a great operating +system. + + + +Please contact me in a case of bug report, suggestions, or just about +anything concerning EXT2ED. + + + +Enjoy, + + + +Gadi Oxman <tgud@tochnapc2.technion.ac.il> + + + +Haifa, August 95 + + + + +
diff --git a/ext2ed/ext2.descriptors b/ext2ed/ext2.descriptors new file mode 100644 index 0000000..e356f4c --- /dev/null +++ b/ext2ed/ext2.descriptors @@ -0,0 +1,976 @@ +Extended 2 filesystem structure definitions for ext2ed. + +Most of this file is just copied from the ext2 main include file. + +My parser is very primitive - It only searches for the struct keywords, +and uses the variables in there. The rest of the file is just ignored. + +You will find at the end a few additional types which are not available in +the original include file, such as the types "file" and "dir". They have +no variables, but are necessary due to the way ext2ed binds C commands +to specific types. + +Gadi Oxman, 7/95 + +Here is the original copyright: + +/* + * linux/include/linux/ext2_fs.h + * + * Copyright (C) 1992, 1993, 1994 Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/include/linux/minix_fs.h + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + + +/* + * ACL structures + */ +struct ext2_acl_header /* Header of Access Control Lists */ +{ + unsigned long aclh_size; + unsigned long aclh_file_count; + unsigned long aclh_acle_count; + unsigned long aclh_first_acle; +}; + +struct ext2_acl_entry /* Access Control List Entry */ +{ + unsigned long acle_size; + unsigned short acle_perms; /* Access permissions */ + unsigned short acle_type; /* Type of entry */ + unsigned short acle_tag; /* User or group identity */ + unsigned short acle_pad1; + unsigned long acle_next; /* Pointer on next entry for the */ + /* same inode or on next free entry */ +}; + +/* + * Structure of a blocks group descriptor + */ + +struct ext2_group_desc +{ + __u32 bg_block_bitmap; /* Blocks bitmap block */ + __u32 bg_inode_bitmap; /* Inodes bitmap block */ + __u32 bg_inode_table; /* Inodes table block */ + __u16 bg_free_blocks_count; /* Free blocks count */ + __u16 bg_free_inodes_count; /* Free inodes count */ + __u16 bg_used_dirs_count; /* Directories count */ + __u16 bg_pad; + __u32 bg_reserved[0]; + __u32 bg_reserved[1]; + __u32 bg_reserved[2]; +}; + +/* + * Structure of an inode on the disk + */ +struct ext2_inode { + __u16 i_mode; /* File mode */ + __u16 i_uid; /* Owner Uid */ + __u32 i_size; /* Size in bytes */ + __u32 i_atime; /* Access time */ + __u32 i_ctime; /* Creation time */ + __u32 i_mtime; /* Modification time */ + __u32 i_dtime; /* Deletion Time */ + __u16 i_gid; /* Group Id */ + __u16 i_links_count; /* Links count */ + __u32 i_blocks; /* Blocks count */ + __u32 i_flags; /* File flags */ + __u32 l_i_reserved1; + __u32 i_block[0]; /* Pointers to blocks */ + __u32 i_block[1]; /* Pointers to blocks */ + __u32 i_block[2]; /* Pointers to blocks */ + __u32 i_block[3]; /* Pointers to blocks */ + __u32 i_block[4]; /* Pointers to blocks */ + __u32 i_block[5]; /* Pointers to blocks */ + __u32 i_block[6]; /* Pointers to blocks */ + __u32 i_block[7]; /* Pointers to blocks */ + __u32 i_block[8]; /* Pointers to blocks */ + __u32 i_block[9]; /* Pointers to blocks */ + __u32 i_block[10]; /* Pointers to blocks */ + __u32 i_block[11]; /* Pointers to blocks */ + __u32 i_block[12]; /* Pointers to blocks */ + __u32 i_block[13]; /* Pointers to blocks */ + __u32 i_block[14]; /* Pointers to blocks */ + __u32 i_version; /* File version (for NFS) */ + __u32 i_file_acl; /* File ACL */ + __u32 i_size_high; /* High 32bits of size */ + __u32 i_faddr; /* Fragment address */ + __u8 l_i_frag; /* Fragment number */ + __u8 l_i_fsize; /* Fragment size */ + __u16 i_pad1; + __u16 l_i_uid_high; /* these 2 fields */ + __u16 l_i_gid_high; /* were reserved2[0] */ + __u32 l_i_reserved2; +}; + +/* + * Structure of the super block + */ +struct ext2_super_block { + __u32 s_inodes_count; /* Inodes count */ + __u32 s_blocks_count; /* Blocks count */ + __u32 s_r_blocks_count; /* Reserved blocks count */ + __u32 s_free_blocks_count; /* Free blocks count */ + __u32 s_free_inodes_count; /* Free inodes count */ + __u32 s_first_data_block; /* First Data Block */ + __u32 s_log_block_size; /* Block size */ + __s32 s_log_frag_size; /* Fragment size */ + __u32 s_blocks_per_group; /* # Blocks per group */ + __u32 s_frags_per_group; /* # Fragments per group */ + __u32 s_inodes_per_group; /* # Inodes per group */ + __u32 s_mtime; /* Mount time */ + __u32 s_wtime; /* Write time */ + __u16 s_mnt_count; /* Mount count */ + __s16 s_max_mnt_count; /* Maximal mount count */ + __u16 s_magic; /* Magic signature */ + __u16 s_state; /* File system state */ + __u16 s_errors; /* Behaviour when detecting errors */ + __u16 s_minor_rev_level; /* minor revision level */ + __u32 s_lastcheck; /* time of last check */ + __u32 s_checkinterval; /* max. time between checks */ + __u32 s_creator_os; /* OS */ + __u32 s_rev_level; /* Revision level */ + __u16 s_def_resuid; /* Default uid for reserved blocks */ + __u16 s_def_resgid; /* Default gid for reserved blocks */ + __u32 s_first_ino; /* First non-reserved inode */ + __u16 s_inode_size; /* size of inode structure */ + __u16 s_block_group_nr; /* block group # of this superblock */ + __u32 s_feature_compat; /* compatible feature set */ + __u32 s_feature_incompat; /* incompatible feature set */ + __u32 s_feature_ro_compat; /* readonly-compatible feature set */ + char[16] s_uuid; /* 128-bit uuid for volume */ + char[16] s_volume_name; /* volume name */ + char[64] s_last_mounted; /* directory where last mounted */ + __u32 s_algorithm_usage_bitmap; /* For compression */ + /* + * Performance hints. 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+ __u32 s_reserved[141]; + __u32 s_reserved[142]; + __u32 s_reserved[143]; + __u32 s_reserved[144]; + __u32 s_reserved[145]; + __u32 s_reserved[146]; + __u32 s_reserved[147]; + __u32 s_reserved[148]; + __u32 s_reserved[149]; + __u32 s_reserved[150]; + __u32 s_reserved[151]; + __u32 s_reserved[152]; + __u32 s_reserved[153]; + __u32 s_reserved[154]; + __u32 s_reserved[155]; + __u32 s_reserved[156]; + __u32 s_reserved[157]; + __u32 s_reserved[158]; + __u32 s_reserved[159]; + __u32 s_reserved[160]; + __u32 s_reserved[161]; + __u32 s_reserved[162]; + __u32 s_reserved[163]; + __u32 s_reserved[164]; + __u32 s_reserved[165]; + __u32 s_reserved[166]; + __u32 s_reserved[167]; + __u32 s_reserved[168]; + __u32 s_reserved[169]; + __u32 s_reserved[170]; + __u32 s_reserved[171]; + __u32 s_reserved[172]; + __u32 s_reserved[173]; + __u32 s_reserved[174]; + __u32 s_reserved[175]; + __u32 s_reserved[176]; + __u32 s_reserved[177]; + __u32 s_reserved[178]; + __u32 s_reserved[179]; + __u32 s_reserved[180]; + __u32 s_reserved[181]; + __u32 s_reserved[182]; + __u32 s_reserved[183]; + __u32 s_reserved[184]; + __u32 s_reserved[185]; + __u32 s_reserved[186]; + __u32 s_reserved[187]; + __u32 s_reserved[188]; + __u32 s_reserved[189]; + __u32 s_reserved[190]; + __u32 s_reserved[191]; + __u32 s_reserved[192]; + __u32 s_reserved[193]; + __u32 s_reserved[194]; + __u32 s_reserved[195]; + __u32 s_reserved[196]; +}; + +The following is actually not used, due to the variable length of the +name field. EXT2ED handles directories through the type "dir" below. + +/* + * Structure of a directory entry + */ + +/* struct ext2_dir_entry { */ +/* + __u32 inode; /* Inode number */ + __u16 rec_len; /* Directory entry length */ + __u16 name_len; /* Name length */ + char name[EXT2_NAME_LEN]; /* File name */ +}; +*/ + +struct file { +}; + +struct dir { +}; + +struct block_bitmap { +}; + +struct inode_bitmap { +}; + +struct ext2_dx_root_node { + __u32 dot_inode; + __u16 dot_rec_len; + __u8 dot_name_len; + __u8 dot_file_type; + char[4] dot_name; + __u32 dot_dot_inode; + __u16 dot_dot_rec_len; + __u8 dot_dot_name_len; + __u8 dot_dot_file_type; + char[4] dot_dot_name; + __u32 reserved_zero; + __u8 hash_version; /* 0 now, 1 at release */ + __u8 info_length; /* 8 */ + __u8 indirect_levels; + __u8 unused_flags; + __u16 limit; + __u16 count; + __u32 block[0]; + __u32 hash[1]; + __u32 block[1]; + __u32 hash[2]; + __u32 block[2]; + __u32 hash[3]; + __u32 block[3]; + __u32 hash[4]; + __u32 block[4]; + __u32 hash[5]; + __u32 block[5]; + __u32 hash[6]; + __u32 block[6]; + __u32 hash[7]; + __u32 block[7]; + __u32 hash[8]; + __u32 block[8]; + __u32 hash[9]; + __u32 block[9]; + __u32 hash[10]; + __u32 block[10]; + __u32 hash[11]; + __u32 block[11]; + __u32 hash[12]; + __u32 block[12]; + __u32 hash[13]; + __u32 block[13]; + __u32 hash[14]; + __u32 block[14]; + __u32 hash[15]; + __u32 block[15]; + __u32 hash[16]; + __u32 block[16]; + __u32 hash[17]; + __u32 block[17]; + __u32 hash[18]; + __u32 block[18]; + __u32 hash[19]; + __u32 block[19]; + __u32 hash[20]; + __u32 block[20]; + __u32 hash[21]; + __u32 block[21]; + __u32 hash[22]; + __u32 block[22]; + __u32 hash[23]; + __u32 block[23]; + __u32 hash[24]; + __u32 block[24]; + __u32 hash[25]; + __u32 block[25]; + __u32 hash[26]; + __u32 block[26]; + __u32 hash[27]; + __u32 block[27]; + __u32 hash[28]; + __u32 block[28]; + __u32 hash[29]; + __u32 block[29]; + __u32 hash[30]; + __u32 block[30]; + __u32 hash[31]; + __u32 block[31]; + __u32 hash[32]; + __u32 block[32]; + __u32 hash[33]; + __u32 block[33]; + __u32 hash[34]; + __u32 block[34]; + __u32 hash[35]; + __u32 block[35]; + __u32 hash[36]; + __u32 block[36]; + __u32 hash[37]; + __u32 block[37]; + __u32 hash[38]; + __u32 block[38]; + __u32 hash[39]; + __u32 block[39]; + __u32 hash[40]; + __u32 block[40]; + __u32 hash[41]; + __u32 block[41]; + __u32 hash[42]; + __u32 block[42]; + __u32 hash[43]; + __u32 block[43]; + __u32 hash[44]; + __u32 block[44]; + __u32 hash[45]; + __u32 block[45]; + __u32 hash[46]; + __u32 block[46]; + __u32 hash[47]; + __u32 block[47]; + __u32 hash[48]; + __u32 block[48]; + __u32 hash[49]; + __u32 block[49]; + __u32 hash[50]; + __u32 block[50]; + __u32 hash[51]; + __u32 block[51]; + __u32 hash[52]; + __u32 block[52]; + __u32 hash[53]; + __u32 block[53]; + __u32 hash[54]; + __u32 block[54]; + __u32 hash[55]; + __u32 block[55]; + __u32 hash[56]; + __u32 block[56]; + __u32 hash[57]; + __u32 block[57]; + __u32 hash[58]; + __u32 block[58]; + __u32 hash[59]; + __u32 block[59]; + __u32 hash[60]; + __u32 block[60]; + __u32 hash[61]; + __u32 block[61]; + __u32 hash[62]; + __u32 block[62]; + __u32 hash[63]; + __u32 block[63]; + __u32 hash[64]; + __u32 block[64]; + __u32 hash[65]; + __u32 block[65]; + __u32 hash[66]; + __u32 block[66]; + __u32 hash[67]; + __u32 block[67]; + __u32 hash[68]; + __u32 block[68]; + __u32 hash[69]; + __u32 block[69]; + __u32 hash[70]; + __u32 block[70]; + __u32 hash[71]; + __u32 block[71]; + __u32 hash[72]; + __u32 block[72]; + __u32 hash[73]; + __u32 block[73]; + __u32 hash[74]; + __u32 block[74]; + __u32 hash[75]; + __u32 block[75]; + __u32 hash[76]; + __u32 block[76]; + __u32 hash[77]; + __u32 block[77]; + __u32 hash[78]; + __u32 block[78]; + __u32 hash[79]; + __u32 block[79]; + __u32 hash[80]; + __u32 block[80]; + __u32 hash[81]; + __u32 block[81]; + __u32 hash[82]; + __u32 block[82]; + __u32 hash[83]; + __u32 block[83]; + __u32 hash[84]; + __u32 block[84]; + __u32 hash[85]; + __u32 block[85]; + __u32 hash[86]; + __u32 block[86]; + __u32 hash[87]; + __u32 block[87]; + __u32 hash[88]; + __u32 block[88]; + __u32 hash[89]; + __u32 block[89]; + __u32 hash[80]; + __u32 block[80]; + __u32 hash[81]; + __u32 block[81]; + __u32 hash[82]; + __u32 block[82]; + __u32 hash[83]; + __u32 block[83]; + __u32 hash[84]; + __u32 block[84]; + __u32 hash[85]; + __u32 block[85]; + __u32 hash[86]; + __u32 block[86]; + __u32 hash[87]; + __u32 block[87]; + __u32 hash[88]; + __u32 block[88]; + __u32 hash[89]; + __u32 block[89]; + __u32 hash[90]; + __u32 block[90]; + __u32 hash[91]; + __u32 block[91]; + __u32 hash[92]; + __u32 block[92]; + __u32 hash[93]; + __u32 block[93]; + __u32 hash[94]; + __u32 block[94]; + __u32 hash[95]; + __u32 block[95]; + __u32 hash[96]; + __u32 block[96]; + __u32 hash[97]; + __u32 block[97]; + __u32 hash[98]; + __u32 block[98]; + __u32 hash[99]; + __u32 block[99]; + __u32 hash[100]; + __u32 block[100]; + __u32 hash[101]; + __u32 block[101]; + __u32 hash[102]; + __u32 block[102]; + __u32 hash[103]; + __u32 block[103]; + __u32 hash[104]; + __u32 block[104]; + __u32 hash[105]; + __u32 block[105]; + __u32 hash[106]; + __u32 block[106]; + __u32 hash[107]; + __u32 block[107]; + __u32 hash[108]; + __u32 block[108]; + __u32 hash[109]; + __u32 block[109]; + __u32 hash[110]; + __u32 block[110]; + __u32 hash[111]; + __u32 block[111]; + __u32 hash[112]; + __u32 block[112]; + __u32 hash[113]; + __u32 block[113]; + __u32 hash[114]; + __u32 block[114]; + __u32 hash[115]; + __u32 block[115]; + __u32 hash[116]; + __u32 block[116]; + __u32 hash[117]; + __u32 block[117]; + __u32 hash[118]; + __u32 block[118]; + __u32 hash[119]; + __u32 block[119]; + __u32 hash[120]; + __u32 block[120]; + __u32 hash[121]; + __u32 block[121]; + __u32 hash[122]; + __u32 block[122]; + __u32 hash[123]; + __u32 block[123]; + __u32 hash[124]; + __u32 block[124]; + __u32 hash[125]; + __u32 block[125]; + __u32 hash[126]; + __u32 block[126]; + __u32 hash[127]; + __u32 block[127]; +}; + +struct ext2_dx_int_node { + __u32 fake_inode; + __u16 fake_rec_len; + __u8 fake_name_len; + __u8 fake_file_type; + __u16 limit; + __u16 count; + __u32 block[0]; + __u32 hash[1]; + __u32 block[1]; + __u32 hash[2]; + __u32 block[2]; + __u32 hash[3]; + __u32 block[3]; + __u32 hash[4]; + __u32 block[4]; + __u32 hash[5]; + __u32 block[5]; + __u32 hash[6]; + __u32 block[6]; + __u32 hash[7]; + __u32 block[7]; + __u32 hash[8]; + __u32 block[8]; + __u32 hash[9]; + __u32 block[9]; + __u32 hash[10]; + __u32 block[10]; + __u32 hash[11]; + __u32 block[11]; + __u32 hash[12]; + __u32 block[12]; + __u32 hash[13]; + __u32 block[13]; + __u32 hash[14]; + __u32 block[14]; + __u32 hash[15]; + __u32 block[15]; + __u32 hash[16]; + __u32 block[16]; + __u32 hash[17]; + __u32 block[17]; + __u32 hash[18]; + __u32 block[18]; + __u32 hash[19]; + __u32 block[19]; + __u32 hash[20]; + __u32 block[20]; + __u32 hash[21]; + __u32 block[21]; + __u32 hash[22]; + __u32 block[22]; + __u32 hash[23]; + __u32 block[23]; + __u32 hash[24]; + __u32 block[24]; + __u32 hash[25]; + __u32 block[25]; + __u32 hash[26]; + __u32 block[26]; + __u32 hash[27]; + __u32 block[27]; + __u32 hash[28]; + __u32 block[28]; + __u32 hash[29]; + __u32 block[29]; + __u32 hash[30]; + __u32 block[30]; + __u32 hash[31]; + __u32 block[31]; + __u32 hash[32]; + __u32 block[32]; + __u32 hash[33]; + __u32 block[33]; + __u32 hash[34]; + __u32 block[34]; + __u32 hash[35]; + __u32 block[35]; + __u32 hash[36]; + __u32 block[36]; + __u32 hash[37]; + __u32 block[37]; + __u32 hash[38]; + __u32 block[38]; + __u32 hash[39]; + __u32 block[39]; + __u32 hash[40]; + __u32 block[40]; + __u32 hash[41]; + __u32 block[41]; + __u32 hash[42]; + __u32 block[42]; + __u32 hash[43]; + __u32 block[43]; + __u32 hash[44]; + __u32 block[44]; + __u32 hash[45]; + __u32 block[45]; + __u32 hash[46]; + __u32 block[46]; + __u32 hash[47]; + __u32 block[47]; + __u32 hash[48]; + __u32 block[48]; + __u32 hash[49]; + __u32 block[49]; + __u32 hash[50]; + __u32 block[50]; + __u32 hash[51]; + __u32 block[51]; + __u32 hash[52]; + __u32 block[52]; + __u32 hash[53]; + __u32 block[53]; + __u32 hash[54]; + __u32 block[54]; + __u32 hash[55]; + __u32 block[55]; + __u32 hash[56]; + __u32 block[56]; + __u32 hash[57]; + __u32 block[57]; + __u32 hash[58]; + __u32 block[58]; + __u32 hash[59]; + __u32 block[59]; + __u32 hash[60]; + __u32 block[60]; + __u32 hash[61]; + __u32 block[61]; + __u32 hash[62]; + __u32 block[62]; + __u32 hash[63]; + __u32 block[63]; + __u32 hash[64]; + __u32 block[64]; + __u32 hash[65]; + __u32 block[65]; + __u32 hash[66]; + __u32 block[66]; + __u32 hash[67]; + __u32 block[67]; + __u32 hash[68]; + __u32 block[68]; + __u32 hash[69]; + __u32 block[69]; + __u32 hash[70]; + __u32 block[70]; + __u32 hash[71]; + __u32 block[71]; + __u32 hash[72]; + __u32 block[72]; + __u32 hash[73]; + __u32 block[73]; + __u32 hash[74]; + __u32 block[74]; + __u32 hash[75]; + __u32 block[75]; + __u32 hash[76]; + __u32 block[76]; + __u32 hash[77]; + __u32 block[77]; + __u32 hash[78]; + __u32 block[78]; + __u32 hash[79]; + __u32 block[79]; + __u32 hash[80]; + __u32 block[80]; + __u32 hash[81]; + __u32 block[81]; + __u32 hash[82]; + __u32 block[82]; + __u32 hash[83]; + __u32 block[83]; + __u32 hash[84]; + __u32 block[84]; + __u32 hash[85]; + __u32 block[85]; + __u32 hash[86]; + __u32 block[86]; + __u32 hash[87]; + __u32 block[87]; + __u32 hash[88]; + __u32 block[88]; + __u32 hash[89]; + __u32 block[89]; + __u32 hash[80]; + __u32 block[80]; + __u32 hash[81]; + __u32 block[81]; + __u32 hash[82]; + __u32 block[82]; + __u32 hash[83]; + __u32 block[83]; + __u32 hash[84]; + __u32 block[84]; + __u32 hash[85]; + __u32 block[85]; + __u32 hash[86]; + __u32 block[86]; + __u32 hash[87]; + __u32 block[87]; + __u32 hash[88]; + __u32 block[88]; + __u32 hash[89]; + __u32 block[89]; + __u32 hash[90]; + __u32 block[90]; + __u32 hash[91]; + __u32 block[91]; + __u32 hash[92]; + __u32 block[92]; + __u32 hash[93]; + __u32 block[93]; + __u32 hash[94]; + __u32 block[94]; + __u32 hash[95]; + __u32 block[95]; + __u32 hash[96]; + __u32 block[96]; + __u32 hash[97]; + __u32 block[97]; + __u32 hash[98]; + __u32 block[98]; + __u32 hash[99]; + __u32 block[99]; + __u32 hash[100]; + __u32 block[100]; + __u32 hash[101]; + __u32 block[101]; + __u32 hash[102]; + __u32 block[102]; + __u32 hash[103]; + __u32 block[103]; + __u32 hash[104]; + __u32 block[104]; + __u32 hash[105]; + __u32 block[105]; + __u32 hash[106]; + __u32 block[106]; + __u32 hash[107]; + __u32 block[107]; + __u32 hash[108]; + __u32 block[108]; + __u32 hash[109]; + __u32 block[109]; + __u32 hash[110]; + __u32 block[110]; + __u32 hash[111]; + __u32 block[111]; + __u32 hash[112]; + __u32 block[112]; + __u32 hash[113]; + __u32 block[113]; + __u32 hash[114]; + __u32 block[114]; + __u32 hash[115]; + __u32 block[115]; + __u32 hash[116]; + __u32 block[116]; + __u32 hash[117]; + __u32 block[117]; + __u32 hash[118]; + __u32 block[118]; + __u32 hash[119]; + __u32 block[119]; + __u32 hash[120]; + __u32 block[120]; + __u32 hash[121]; + __u32 block[121]; + __u32 hash[122]; + __u32 block[122]; + __u32 hash[123]; + __u32 block[123]; + __u32 hash[124]; + __u32 block[124]; + __u32 hash[125]; + __u32 block[125]; + __u32 hash[126]; + __u32 block[126]; + __u32 hash[127]; + __u32 block[127]; +}; + + diff --git a/ext2ed/ext2_com.c b/ext2ed/ext2_com.c new file mode 100644 index 0000000..ed004f2 --- /dev/null +++ b/ext2ed/ext2_com.c @@ -0,0 +1,98 @@ +/* + +/usr/src/ext2ed/ext2_com.c + +A part of the extended file system 2 disk editor. + +-------------------------------------- +Extended-2 filesystem General commands +-------------------------------------- + +The commands here will be registered when we are editing an ext2 filesystem + +First written on: July 28 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include + +#include "ext2ed.h" + +void type_ext2___super (char *command_line) + +/* + +We are moving to the superblock - Just use setoffset and settype. The offset was gathered in the +initialization phase (but is constant - 1024). + +*/ + +{ + char buffer [80]; + + super_info.copy_num=0; + sprintf (buffer,"setoffset %ld",file_system_info.super_block_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_super_block");dispatch (buffer); +} + +void type_ext2___cd (char *command_line) + +/* + +A global cd command - The path should start with /. + +We implement it through dispatching to our primitive functions. + +*/ + +{ + char temp [80],buffer [80],*ptr; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + if (buffer [0] != '/') { + wprintw (command_win,"Error - Use a full pathname (begin with '/')\n");refresh_command_win ();return; + } + + /* Note the various dispatches below - They should be intuitive if you know the ext2 filesystem structure */ + + dispatch ("super");dispatch ("group");dispatch ("inode");dispatch ("next");dispatch ("dir"); + if (buffer [1] != 0) { + sprintf (temp,"cd %s",buffer+1);dispatch (temp); + } +} + +void type_ext2___group (char *command_line) + +/* + +We go to the group descriptors. +First, we go to the first group descriptor in the main copy. +Then, we use the group's entry command to pass to another group. + +*/ + +{ + long group_num=0; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + group_num=atol (buffer); + } + + group_info.copy_num=0;group_info.group_num=0; + sprintf (buffer,"setoffset %ld",file_system_info.first_group_desc_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_group_desc");dispatch (buffer); + sprintf (buffer,"entry %ld",group_num);dispatch (buffer); +} diff --git a/ext2ed/ext2ed.8.in b/ext2ed/ext2ed.8.in new file mode 100644 index 0000000..e827277 --- /dev/null +++ b/ext2ed/ext2ed.8.in @@ -0,0 +1,72 @@ +.\" -*- nroff -*- +.TH EXT2ED 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@" +.SH NAME +ext2ed \- ext2 file system editor +.SH SYNOPSIS +.B ext2ed +.SH DESCRIPTION +.B ext2ed +in an +.B editor +for the +.B second extended file system. +Its aim is to show you the various internal file system structures in an +intuitive form so that you would be able to easily understand and modify +them. +.SH DOCUMENTATION +The documentation is not available in man page format. Instead, I have +written three articles which are related to ext2ed: + +The first article is +.B The user's guide. +This article explains how to use ext2ed. + +The second article is +.B The Ext2fs overview. +This article gives an overview of internal structure of the ext2 file system. +You need to understand the internal layout in order to effectively edit +your file system. + +The third article is +.B EXT2ED - Design and implementation. +This article explains how I constructed ext2ed. You may want to have a look +in it if you plan to view or modify the source code. + +.SH WARNING + +.B +Do not use ext2ed on a mounted file system. + +.SH FILES +.TP +.I /usr/bin/ext2ed +The program itself. +.TP +.I @root_sysconfdir@/ext2ed.conf +ext2ed's configuration file. +.TP +.I @datadir@/ext2.descriptors +Definition of the various objects for the ext2 file system. +.TP +.I /var/log/ext2ed.log +Log file of actual changes made to the file system. +.TP +.I /usr/man/man8/ext2ed.8 +The manual page. +.TP +.I @datadir@/doc/ext2ed/user-guide-0.1.ps +The user's guide. +.TP +.I @datadir@/doc/ext2ed/Ext2fs-overview-0.1.ps +Technical overview of the ext2 file system. +.TP +.I @datadir@/doc/ext2ed/ext2ed-design-0.1.ps +EXT2ED design notes. + +.SH BUGS +File Systems bigger than 2 GB aren't yet supported. +.SH AUTHOR +Gadi Oxman +.SH SEE ALSO +.BR e2fsck (8), +.BR debugfs (8) diff --git a/ext2ed/ext2ed.conf.in b/ext2ed/ext2ed.conf.in new file mode 100644 index 0000000..c079623 --- /dev/null +++ b/ext2ed/ext2ed.conf.in @@ -0,0 +1,79 @@ +############################################################################## +# ext2ed.conf # +# # +# Configuration file for the extended 2 file system disk editor. # +############################################################################## + +# Ext2Descriptors is the location of the ext2 filesystem structure +# definitions. + + +Ext2Descriptors @datadir@/ext2.descriptors + + +# Using AlternateDescriptors you can declare additional structures. Those +# structures can contain only variables. Linking functions to the objects is +# possible only through source code additions. + + +AlternateDescriptors + + +# LogFile is the location of the log file. Actual changes to the filesystem +# are logged there. See also LogChanges. + + +LogFile /var/log/ext2ed.log + + +# The following selects the default behavior when changes are made to the +# filesystem. When on, each change will be logged - Both the previous data +# and the new written data. + + +LogChanges on + + +# AllowChanges off will not allow ext2ed to do any changes to the +# filesystem - The "enablewrite" command will not work. When on, enablewrite +# will still have to be issued to allow write access. + + +AllowChanges on + + +# With this option you can choose whether ext2ed will allow read-only mode on +# a mounted filesystem. Read-Write mode is never allowed on a mounted +# filesystem. + + +AllowMountedRead on + + +# When ForceExt2 is set to on, the filesystem is assumed to be ext2 +# filesystem, despite the possibly corrupt superblock magic number reading. +# All the ext2 specific commands will be available despite the possible +# autodetection failure. + +ForceExt2 off + + +# Normally, the various filesystem parameters such as the block size and the +# total number of blocks are gathered from the ext2 filesystem itself. +# However, on a corrupt filesystem, ext2ed is unable to get the right +# parameters. In this case, they will be taken from here. See also +# ForceDefault. + + +DefaultBlockSize 1024 +DefaultTotalBlocks 2097151 # ~2 GB total size +DefaultBlocksInGroup 8192 + +# With ForceDefault on, you can force the use of the default parameters +# above. This is not recommended, as ext2ed will fallback by default to those +# parameters if it can't figure up the parameters from the filesystem itself. + + +ForceDefault off + + diff --git a/ext2ed/ext2ed.h b/ext2ed/ext2ed.h new file mode 100644 index 0000000..0ac77b7 --- /dev/null +++ b/ext2ed/ext2ed.h @@ -0,0 +1,435 @@ + +/* + +/usr/src/ext2ed/ext2ed.h + +A part of the extended file system 2 disk editor. + +-------------------------------------- +Include file for the ext2 disk editor. +-------------------------------------- + +This file contains declarations which are needed by all the files in ext2ed. + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#ifndef EXT2ED_EDITOR_H +#define EXT2ED_EDITOR_H + +/* + +----------------------- + User definable options +----------------------- + +*/ + +#define DEBUG /* Activate self-sanity checks */ + +#include /* Main kernel ext2 include file */ +#include + +#include + +#define MAX_FIELDS 400 + +#define MAX_COMMAND_LINE 81 +#define MAX_COMMANDS_NUM 30 /* Maximum number of commands of one type */ +#define REMEMBER_COUNT 30 /* Object memory size */ + +/* + The user screen consists of four parts: + + 1. Title window (title_win). + 2. Show (status) window (show_win). + 3. Main show pad (show_pad). + 4. Command window (command_win). + +*/ + +/* + + The show pad is mapped to the space left between the other three windows. + + If you wondered why ext2ed grabs so memory, the answer is probably below - I wanted to treat + the virtual display as infinite. Decrease the following for more realistic memory consumption. + +*/ + +#define SHOW_PAD_LINES 3000 +#define SHOW_PAD_COLS (COLS > 140 ? COLS : 140) + +#define COMMAND_WIN_LINES 6 /* Change this to your preferences */ +#define TITLE_WIN_LINES 3 +#define SHOW_WIN_LINES 3 + +#define HEX 1 +#define TEXT 2 + +#ifndef EXT2_PRE_02B_MAGIC + #define EXT2_PRE_02B_MAGIC 0xEF51 +#endif + + +typedef void (*PF) (char *); /* Used to point to the dispatched functions */ + +struct struct_commands { /* Holds commands of an object */ + int last_command; + char *names [MAX_COMMANDS_NUM]; + char *descriptions [MAX_COMMANDS_NUM]; + PF callback [MAX_COMMANDS_NUM]; +}; + +struct struct_descriptor { /* Describes an object */ + unsigned long length; + unsigned char name [60]; + unsigned short fields_num; + unsigned char field_names [MAX_FIELDS][80]; + unsigned char field_types [MAX_FIELDS]; + unsigned short field_lengths [MAX_FIELDS]; + unsigned short field_positions [MAX_FIELDS]; + struct struct_commands type_commands; + struct struct_descriptor *prev,*next; +}; + +#define FIELD_TYPE_INT 1 +#define FIELD_TYPE_UINT 2 +#define FIELD_TYPE_CHAR 3 + +struct struct_type_data { /* The object's data is usually here */ + long offset_in_block; + + union union_type_data { /* Format it in various ways */ + char buffer [EXT2_MAX_BLOCK_SIZE]; + struct ext2_acl_header t_ext2_acl_header; + struct ext2_acl_entry t_ext2_acl_entry; + struct ext2_group_desc t_ext2_group_desc; + struct ext2_inode t_ext2_inode; + struct ext2_super_block t_ext2_super_block; + struct ext2_dir_entry t_ext2_dir_entry; + } u; +}; + +struct struct_file_system_info { /* Important information about the filesystem */ + unsigned long long file_system_size; + unsigned long super_block_offset; + unsigned long first_group_desc_offset; + unsigned long groups_count; + unsigned long inodes_per_block; + unsigned long blocks_per_group; /* The name is misleading; beware */ + unsigned long no_blocks_in_group; + unsigned short block_size; + struct ext2_super_block super_block; +}; + +struct struct_file_info { /* Used to handle files and directories */ + + struct ext2_inode *inode_ptr; + + long inode_offset; + long global_block_num,global_block_offset; + long block_num,blocks_count; + long file_offset,file_length; + long level; + unsigned char buffer [EXT2_MAX_BLOCK_SIZE]; + long offset_in_block; + + int display; + /* The following is used if the file is a directory */ + + long dir_entry_num,dir_entries_count; + long dir_entry_offset; +}; + +struct struct_super_info { /* Used to handle the superblock */ + unsigned long copy_num; +}; + +struct struct_group_info { /* Used to handle the group descriptors */ + unsigned long copy_num; + unsigned long group_num; +}; + +struct struct_block_bitmap_info { /* Used in blockbitmap_com.c */ + unsigned long entry_num; + unsigned long group_num; +}; + +struct struct_inode_bitmap_info { /* Used in inodebitmap_com.c */ + unsigned long entry_num; + unsigned long group_num; +}; + +struct struct_remember_lifo { /* Implements the objects circular memory */ + long entries_count; + + long offset [REMEMBER_COUNT]; + struct struct_descriptor *type [REMEMBER_COUNT]; + char name [REMEMBER_COUNT][80]; +}; + +struct struct_pad_info { /* Used to zoom into the pad window */ + int display_lines,display_cols; + int line,col; + int max_line,max_col; + int disable_output; +}; + +/* Global variables (defined mostly in main.c) */ + +/* Configurable variables (Through configuration file) */ + +extern char AlternateDescriptors [200]; +extern char Ext2Descriptors [200]; +extern char LogFile [200]; +extern int LogChanges; +extern int AllowChanges; +extern int AllowMountedRead; +extern int ForceExt2; +extern int DefaultBlockSize; +extern unsigned long DefaultTotalBlocks; +extern unsigned long DefaultBlocksInGroup; +extern int ForceDefault; + +extern char device_name [80]; +extern char last_command_line [80]; +extern FILE *device_handle; +extern long device_offset; +extern int mounted; + +extern short block_size; +extern struct struct_commands general_commands; +extern struct struct_commands ext2_commands; +extern struct struct_descriptor *first_type; +extern struct struct_descriptor *last_type; +extern struct struct_descriptor *current_type; +extern struct struct_type_data type_data; +extern struct struct_file_system_info file_system_info; +extern struct struct_file_info file_info,first_file_info; +extern struct struct_group_info group_info; +extern struct struct_super_info super_info; +extern struct struct_block_bitmap_info block_bitmap_info; +extern struct struct_inode_bitmap_info inode_bitmap_info; +extern struct struct_remember_lifo remember_lifo; +extern struct struct_pad_info show_pad_info; +extern int write_access; + +extern int redraw_request; +extern char lines_s [80]; +extern char cols_s [80]; + + +/* init.c */ + +extern int init (void); +extern void prepare_to_close (void); +extern int set_struct_descriptors (char *file_name); +extern void free_struct_descriptors (void); +extern struct struct_descriptor *add_new_descriptor (char *name); +extern void add_new_variable (struct struct_descriptor *descriptor,char *v_type,char *v_name); +extern void fill_type_commands (struct struct_descriptor *ptr); +extern void add_user_command (struct struct_commands *ptr,char *name,char *description,PF callback); +extern void free_user_commands (struct struct_commands *ptr); +extern int set_file_system_info (void); +extern int process_configuration_file (void); +extern void add_general_commands (void); +extern void add_ext2_general_commands (void); +extern void check_mounted (char *name); + +int get_next_option (FILE *fp,char *option,char *value); +void init_readline (void); +void init_signals (void); +void signal_SIGWINCH_handler (int sig_num); +void signal_SIGTERM_handler (int sig_num); +void signal_SIGSEGV_handler (int sig_num); + +/* general_com.c */ + +/* General commands which are available always */ + +extern void help (char *command_line); +extern void set (char *command_line); +extern void set_device (char *command_line); +extern void set_offset (char *command_line); +extern void set_type (char *command_line); +extern void show (char *command_line); +extern void pgup (char *command_line); +extern void pgdn (char *command_line); +extern void redraw (char *command_line); +extern void remember (char *command_line); +extern void recall (char *command_line); +extern void cd (char *command_line); +extern void enable_write (char *command_line); +extern void disable_write (char *command_line); +extern void write_data (char *command_line); +extern void next (char *command_line); +extern void prev (char *command_line); + +void hex_set (char *command_line); +void detailed_help (char *text); + + +/* ext2_com.c */ + +/* Extended2 filesystem general commands - Available only when editing an + ext2 filesystem */ + +extern void type_ext2___super (char *command_line); +extern void type_ext2___group (char *command_line); +extern void type_ext2___cd (char *command_line); + + +/* main.c */ + +extern int version_major,version_minor; +extern char revision_date [80]; +extern char email_address [80]; + +#ifdef DEBUG +extern void internal_error (char *description,char *source_name,char *function_name); +#endif + +void parser (void); +extern int dispatch (char *command_line); +char *parse_word (char *source,char *dest); +char *complete_command (char *text,int state); +char *dupstr (char *src); + + + +/* disk.c */ + +extern int load_type_data (void); +extern int write_type_data (void); +extern int low_read (unsigned char *buffer,unsigned long length,unsigned long offset); +extern int low_write (unsigned char *buffer,unsigned long length,unsigned long offset); +extern int log_changes (unsigned char *buffer,unsigned long length,unsigned long offset); + +/* file_com.c */ + +extern int init_file_info (void); +extern void type_file___show (char *command_line); +extern void type_file___inode (char *command_line); +extern void type_file___display (char *command_line); +extern void type_file___prev (char *command_line); +extern void type_file___next (char *command_line); +extern void type_file___offset (char *command_line); +extern void type_file___prevblock (char *command_line); +extern void type_file___nextblock (char *command_line); +extern void type_file___block (char *command_line); +extern void type_file___remember (char *command_line); +extern void type_file___set (char *command_line); +extern void type_file___writedata (char *command_line); + +extern long file_block_to_global_block (long file_block,struct struct_file_info *file_info_ptr); +extern long return_indirect (long table_block,long block_num); +extern long return_dindirect (long table_block,long block_num); +extern long return_tindirect (long table_block,long block_num); + +void file_show_hex (void); +void file_show_text (void); +void show_status (void); + +/* inode_com.c */ + +extern void type_ext2_inode___next (char *command_line); +extern void type_ext2_inode___prev (char *command_line); +extern void type_ext2_inode___show (char *command_line); +extern void type_ext2_inode___group (char *command_line); +extern void type_ext2_inode___entry (char *command_line); +extern void type_ext2_inode___file (char *command_line); +extern void type_ext2_inode___dir (char *command_line); + +extern long inode_offset_to_group_num (long inode_offset); +extern long int inode_offset_to_inode_num (long inode_offset); +extern long int inode_num_to_inode_offset (long inode_num); + +/* dir_com.c */ + +extern int init_dir_info (struct struct_file_info *info); +extern void type_dir___show (char *command_line); +extern void type_dir___inode (char *command_line); +extern void type_dir___pgdn (char *command_line); +extern void type_dir___pgup (char *command_line); +extern void type_dir___prev (char *command_line); +extern void type_dir___next (char *command_line); +extern void type_dir___followinode (char *command_line); +extern void type_dir___remember (char *command_line); +extern void type_dir___cd (char *command_line); +extern void type_dir___entry (char *command_line); +extern void type_dir___writedata (char *command_line); +extern void type_dir___set (char *command_line); + +#define HEX 1 +#define TEXT 2 + +#define ABORT 0 +#define CONTINUE 1 +#define FOUND 2 + +struct struct_file_info search_dir_entries (int (*action) (struct struct_file_info *info),int *status); +int action_count (struct struct_file_info *info); +void show_dir_status (void); +long count_dir_entries (void); +int action_name (struct struct_file_info *info); +int action_entry_num (struct struct_file_info *info); +int action_show (struct struct_file_info *info); + +/* super_com.c */ + +extern void type_ext2_super_block___show (char *command_line); +extern void type_ext2_super_block___gocopy (char *command_line); +extern void type_ext2_super_block___setactivecopy (char *command_line); + +/* group_com.c */ + +extern void type_ext2_group_desc___next (char *command_line); +extern void type_ext2_group_desc___prev (char *command_line); +extern void type_ext2_group_desc___entry (char *command_line); +extern void type_ext2_group_desc___show (char *command_line); +extern void type_ext2_group_desc___inode (char *command_line); +extern void type_ext2_group_desc___gocopy (char *command_line); +extern void type_ext2_group_desc___blockbitmap (char *command_line); +extern void type_ext2_group_desc___inodebitmap (char *command_line); +extern void type_ext2_group_desc___setactivecopy (char *command_line); + +/* blockbitmap_com.c */ + +extern void type_ext2_block_bitmap___show (char *command_line); +extern void type_ext2_block_bitmap___entry (char *command_line); +extern void type_ext2_block_bitmap___next (char *command_line); +extern void type_ext2_block_bitmap___prev (char *command_line); +extern void type_ext2_block_bitmap___allocate (char *command_line); +extern void type_ext2_block_bitmap___deallocate (char *command_line); +void allocate_block (long entry_num); +void deallocate_block (long entry_num); + +/* inodebitmap_bom.c */ + +extern void type_ext2_inode_bitmap___show (char *command_line); +extern void type_ext2_inode_bitmap___entry (char *command_line); +extern void type_ext2_inode_bitmap___next (char *command_line); +extern void type_ext2_inode_bitmap___prev (char *command_line); +extern void type_ext2_inode_bitmap___allocate (char *command_line); +extern void type_ext2_inode_bitmap___deallocate (char *command_line); +void allocate_inode (long entry_num); +void deallocate_inode (long entry_num); + +/* win.c */ + +extern WINDOW *title_win,*show_win,*command_win,*show_pad; + +extern void init_windows (void); +extern void refresh_title_win (void); +extern void refresh_show_win (void); +extern void refresh_show_pad (void); +extern void refresh_command_win (void); +extern void show_info (void); +extern void redraw_all (void); +extern void close_windows (void); + +#endif /* EXT2ED_EDITOR_H */ diff --git a/ext2ed/file_com.c b/ext2ed/file_com.c new file mode 100644 index 0000000..d667959 --- /dev/null +++ b/ext2ed/file_com.c @@ -0,0 +1,565 @@ +/* + +/usr/src/ext2ed/file_com.c + +A part of the extended file system 2 disk editor. + +---------------------------- +Commands which handle a file +---------------------------- + +First written on: April 18 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include + +#include "ext2ed.h" + +int init_file_info (void) + +{ + struct ext2_inode *ptr; + + ptr=&type_data.u.t_ext2_inode; + + file_info.inode_ptr=ptr; + file_info.inode_offset=device_offset; + + file_info.global_block_num=ptr->i_block [0]; + file_info.global_block_offset=ptr->i_block [0]*file_system_info.block_size; + file_info.block_num=0; + file_info.blocks_count=(ptr->i_size+file_system_info.block_size-1)/file_system_info.block_size; + file_info.file_offset=0; + file_info.file_length=ptr->i_size; + file_info.level=0; + file_info.offset_in_block=0; + + file_info.display=HEX; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + + return (1); +} + + +void type_file___inode (char *command_line) + +{ + dispatch ("settype ext2_inode"); +} + +void type_file___show (char *command_line) + +{ + if (file_info.display==HEX) + file_show_hex (); + if (file_info.display==TEXT) + file_show_text (); +} + +void type_file___nextblock (char *command_line) + +{ + long block_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + block_offset*=atol (buffer); + } + + if (file_info.block_num+block_offset >= file_info.blocks_count) { + wprintw (command_win,"Error - Block offset out of range\n");wrefresh (command_win); + return; + } + + file_info.block_num+=block_offset; + file_info.global_block_num=file_block_to_global_block (file_info.block_num,&file_info); + file_info.global_block_offset=file_info.global_block_num*file_system_info.block_size; + file_info.file_offset=file_info.block_num*file_system_info.block_size; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + + strcpy (buffer,"show");dispatch (buffer); +} + +void type_file___next (char *command_line) + +{ + int offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + if (file_info.offset_in_block+offset < file_system_info.block_size) { + file_info.offset_in_block+=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void type_file___offset (char *command_line) + +{ + unsigned long offset; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset=atol (buffer); + } + else { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win (); + return; + } + + if (offset < file_system_info.block_size) { + file_info.offset_in_block=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void type_file___prev (char *command_line) + +{ + int offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + if (file_info.offset_in_block-offset >= 0) { + file_info.offset_in_block-=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void type_file___prevblock (char *command_line) + +{ + long block_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + block_offset*=atol (buffer); + } + + if (file_info.block_num-block_offset < 0) { + wprintw (command_win,"Error - Block offset out of range\n");wrefresh (command_win); + return; + } + + file_info.block_num-=block_offset; + file_info.global_block_num=file_block_to_global_block (file_info.block_num,&file_info); + file_info.global_block_offset=file_info.global_block_num*file_system_info.block_size; + file_info.file_offset=file_info.block_num*file_system_info.block_size; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + + strcpy (buffer,"show");dispatch (buffer); +} + +void type_file___block (char *command_line) + +{ + long block_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Invalid arguments\n");wrefresh (command_win); + return; + } + + ptr=parse_word (ptr,buffer); + block_offset=atol (buffer); + + if (block_offset < 0 || block_offset >= file_info.blocks_count) { + wprintw (command_win,"Error - Block offset out of range\n");wrefresh (command_win); + return; + } + + file_info.block_num=block_offset; + file_info.global_block_num=file_block_to_global_block (file_info.block_num,&file_info); + file_info.global_block_offset=file_info.global_block_num*file_system_info.block_size; + file_info.file_offset=file_info.block_num*file_system_info.block_size; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + + strcpy (buffer,"show");dispatch (buffer); +} + +void type_file___display (char *command_line) + +{ + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) + strcpy (buffer,"hex"); + else + ptr=parse_word (ptr,buffer); + + if (strcasecmp (buffer,"hex")==0) { + wprintw (command_win,"Display set to hex\n");wrefresh (command_win); + file_info.display=HEX; + sprintf (buffer,"show");dispatch (buffer); + } + + else if (strcasecmp (buffer,"text")==0) { + wprintw (command_win,"Display set to text\n");wrefresh (command_win); + file_info.display=TEXT; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Invalid arguments\n");wrefresh (command_win); + } +} + +void file_show_hex (void) + +{ + long offset=0,l,i; + unsigned char *ch_ptr; + + /* device_offset and type_data points to the inode */ + + show_pad_info.line=0; + + wmove (show_pad,0,0); + ch_ptr=file_info.buffer; + for (l=0;lfile_info.file_length-1) break; + wprintw (show_pad,"%08ld : ",offset); + for (i=0;i<16;i++) { + + if (file_info.file_offset+offset+i>file_info.file_length-1) { + wprintw (show_pad," "); + } + + else { + if (file_info.offset_in_block==offset+i) + wattrset (show_pad,A_REVERSE); + + if (ch_ptr [i]>=' ' && ch_ptr [i]<='z') + wprintw (show_pad,"%c",ch_ptr [i]); + else + wprintw (show_pad,"."); + + if (file_info.offset_in_block==offset+i) + wattrset (show_pad,A_NORMAL); + } + } + + wprintw (show_pad," "); + for (i=0;i<16;i++) { + if (file_info.file_offset+offset+i>file_info.file_length-1) break; + if (file_info.offset_in_block==offset+i) + wattrset (show_pad,A_REVERSE); + + wprintw (show_pad,"%02x",ch_ptr [i]); + + if (file_info.offset_in_block==offset+i) { + wattrset (show_pad,A_NORMAL); + show_pad_info.line=l-l % show_pad_info.display_lines; + } + + wprintw (show_pad," "); + + } + + wprintw (show_pad,"\n"); + offset+=i; + ch_ptr+=i; + } + + show_pad_info.max_line=l-1; + + refresh_show_pad (); + + show_status (); +} + +void file_show_text (void) + +{ + long offset=0,last_offset,l=0,cols=0; + unsigned char *ch_ptr; + + /* device_offset and type_data points to the inode */ + + show_pad_info.line=0; + wmove (show_pad,0,0); + ch_ptr=file_info.buffer; + + last_offset=file_system_info.block_size-1; + + if (file_info.file_offset+last_offset > file_info.file_length-1) + last_offset=file_info.file_length-1-file_info.file_offset; + + while ( (offset <= last_offset) && l= ' ' && *ch_ptr <= 'z') + wprintw (show_pad,"%c",*ch_ptr); + + + else { + if (*ch_ptr == 0xa) { + wprintw (show_pad,"\n"); + l++;cols=0; + } + + else if (*ch_ptr == 0x9) + wprintw (show_pad," "); + + else + wprintw (show_pad,"."); + } + + if (file_info.offset_in_block==offset) { + wattrset (show_pad,A_NORMAL); + show_pad_info.line=l-l % show_pad_info.display_lines; + } + + + offset++;cols++;ch_ptr++; + } + + wprintw (show_pad,"\n"); + show_pad_info.max_line=l; + + refresh_show_pad (); + + show_status (); +} + +void show_status (void) + +{ + long inode_num; + + werase (show_win);wmove (show_win,0,0); + wprintw (show_win,"File contents. Block %ld. ",file_info.global_block_num); + wprintw (show_win,"File block %ld of %ld. ",file_info.block_num,file_info.blocks_count-1); + wprintw (show_win,"File Offset %ld of %ld.",file_info.file_offset,file_info.file_length-1); + + wmove (show_win,1,0); + inode_num=inode_offset_to_inode_num (file_info.inode_offset); + wprintw (show_win,"File inode %ld. Indirection level %ld.",inode_num,file_info.level); + + refresh_show_win (); +} + +void type_file___remember (char *command_line) + +{ + int found=0; + long entry_num; + char *ptr,buffer [80]; + struct struct_descriptor *descriptor_ptr; + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");wrefresh (command_win); + return; + } + + ptr=parse_word (ptr,buffer); + + entry_num=remember_lifo.entries_count++; + if (entry_num>REMEMBER_COUNT-1) { + entry_num=0; + remember_lifo.entries_count--; + } + + descriptor_ptr=first_type; + while (descriptor_ptr!=NULL && !found) { + if (strcmp (descriptor_ptr->name,"ext2_inode")==0) + found=1; + else + descriptor_ptr=descriptor_ptr->next; + } + + + remember_lifo.offset [entry_num]=device_offset; + remember_lifo.type [entry_num]=descriptor_ptr; + strcpy (remember_lifo.name [entry_num],buffer); + + wprintw (command_win,"Object %s in Offset %ld remembered as %s\n",descriptor_ptr->name,device_offset,buffer); + wrefresh (command_win); +} + +void type_file___set (char *command_line) + +{ + unsigned char tmp; + char *ptr,buffer [80],*ch_ptr; + int mode=HEX; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win ();return; + } + + ptr=parse_word (ptr,buffer); + + if (strcasecmp (buffer,"text")==0) { + mode=TEXT; + strcpy (buffer,ptr); + } + + else if (strcasecmp (buffer,"hex")==0) { + mode=HEX; + ptr=parse_word (ptr,buffer); + } + + if (*buffer==0) { + wprintw (command_win,"Error - Data not specified\n");refresh_command_win ();return; + } + + if (mode==HEX) { + do { + tmp=(unsigned char) strtol (buffer,NULL,16); + file_info.buffer [file_info.offset_in_block]=tmp; + file_info.offset_in_block++; + ptr=parse_word (ptr,buffer); + if (file_info.offset_in_block==file_system_info.block_size) { + if (*ptr) { + wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n"); + refresh_command_win (); + } + file_info.offset_in_block--; + } + } while (*buffer) ; + } + + else { + ch_ptr=buffer; + while (*ch_ptr) { + tmp=(unsigned char) *ch_ptr++; + file_info.buffer [file_info.offset_in_block]=tmp; + file_info.offset_in_block++; + if (file_info.offset_in_block==file_system_info.block_size) { + if (*ch_ptr) { + wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n"); + refresh_command_win (); + } + file_info.offset_in_block--; + } + } + } + + strcpy (buffer,"show");dispatch (buffer); +} + +void type_file___writedata (char *command_line) + +{ + low_write (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + return; +} + +long file_block_to_global_block (long file_block,struct struct_file_info *file_info_ptr) + +{ + long last_direct,last_indirect,last_dindirect; + + last_direct=EXT2_NDIR_BLOCKS-1; + last_indirect=last_direct+file_system_info.block_size/4; + last_dindirect=last_indirect+(file_system_info.block_size/4)*(file_system_info.block_size/4); + + if (file_block <= last_direct) { + file_info_ptr->level=0; + return (file_info_ptr->inode_ptr->i_block [file_block]); + } + + if (file_block <= last_indirect) { + file_info_ptr->level=1; + file_block=file_block-last_direct-1; + return (return_indirect (file_info_ptr->inode_ptr->i_block [EXT2_IND_BLOCK],file_block)); + } + + if (file_block <= last_dindirect) { + file_info_ptr->level=2; + file_block=file_block-last_indirect-1; + return (return_dindirect (file_info_ptr->inode_ptr->i_block [EXT2_DIND_BLOCK],file_block)); + } + + file_info_ptr->level=3; + file_block=file_block-last_dindirect-1; + return (return_tindirect (file_info_ptr->inode_ptr->i_block [EXT2_TIND_BLOCK],file_block)); +} + +long return_indirect (long table_block,long block_num) + +{ + long block_table [EXT2_MAX_BLOCK_SIZE/4]; + + low_read ((char *) block_table,file_system_info.block_size,table_block*file_system_info.block_size); + return (block_table [block_num]); +} + +long return_dindirect (long table_block,long block_num) + +{ + long f_indirect; + + f_indirect=block_num/(file_system_info.block_size/4); + f_indirect=return_indirect (table_block,f_indirect); + return (return_indirect (f_indirect,block_num%(file_system_info.block_size/4))); +} + +long return_tindirect (long table_block,long block_num) + +{ + long s_indirect; + + s_indirect=block_num/((file_system_info.block_size/4)*(file_system_info.block_size/4)); + s_indirect=return_indirect (table_block,s_indirect); + return (return_dindirect (s_indirect,block_num%((file_system_info.block_size/4)*(file_system_info.block_size/4)))); +} diff --git a/ext2ed/general_com.c b/ext2ed/general_com.c new file mode 100644 index 0000000..aa274e3 --- /dev/null +++ b/ext2ed/general_com.c @@ -0,0 +1,907 @@ +/* + +/usr/src/ext2ed/general_com.c + +A part of the extended file system 2 disk editor. + +--------------------- +General user commands +--------------------- + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include + +#include "ext2ed.h" +#include "../version.h" + +void help (char *command_line) + +{ + int i,max_line=0; + char argument [80],*ptr; + + werase (show_pad);wmove (show_pad,0,0); + + ptr=parse_word (command_line,argument); + + if (*ptr!=0) { + ptr=parse_word (ptr,argument); + if (*argument!=0) { + detailed_help (argument); + return; + } + } + + if (current_type!=NULL) { + + wprintw (show_pad,"Type %s specific commands:\n",current_type->name);max_line++; + + if (current_type->type_commands.last_command==-1) { + wprintw (show_pad,"\nnone\n");max_line+=2; + } + else + for (i=0;i<=current_type->type_commands.last_command;i++) { + if (i%5==0) { + wprintw (show_pad,"\n");max_line++; + } + wprintw (show_pad,"%-13s",current_type->type_commands.names [i]); + if (i%5!=4) + wprintw (show_pad,"; "); + } + + wprintw (show_pad,"\n\n");max_line+=2; + } + + if (ext2_commands.last_command != -1) { + wprintw (show_pad,"ext2 filesystem general commands: \n");max_line++; + for (i=0;i<=ext2_commands.last_command;i++) { + if (i%5==0) { + wprintw (show_pad,"\n");max_line++; + } + wprintw (show_pad,"%-13s",ext2_commands.names [i]); + if (i%5!=4) + wprintw (show_pad,"; "); + + } + wprintw (show_pad,"\n\n");max_line+=2; + } + + wprintw (show_pad,"General commands: \n"); + + for (i=0;i<=general_commands.last_command;i++) { + if (i%5==0) { + wprintw (show_pad,"\n");max_line++; + } + wprintw (show_pad,"%-13s",general_commands.names [i]); + if (i%5!=4) + wprintw (show_pad,"; "); + } + + wprintw (show_pad,"\n\n");max_line+=2; + + wprintw (show_pad,"EXT2ED ver %s (%s)\n",E2FSPROGS_VERSION, E2FSPROGS_DATE); + wprintw (show_pad,"Copyright (C) 1995 Gadi Oxman\n"); + wprintw (show_pad,"Reviewed 2001 Christian Bac\n"); + wprintw (show_pad,"Modified and enhanced by Theodore Ts'o, 2002\n"); + wprintw (show_pad,"EXT2ED is hereby placed under the terms of the GNU General Public License.\n\n"); + wprintw (show_pad,"EXT2ED was programmed as a student project in the software laboratory\n"); + wprintw (show_pad,"of the faculty of electrical engineering in the\n"); + wprintw (show_pad,"Technion - Israel Institute of Technology\n"); + wprintw (show_pad,"with the guide of Avner Lottem and Dr. Ilana David.\n"); + + max_line+=10; + + show_pad_info.line=0;show_pad_info.max_line=max_line; + + werase (show_win);wmove (show_win,0,0); + wprintw (show_win,"EXT2ED help"); + + refresh_show_win (); + refresh_show_pad (); +} + +void detailed_help (char *text) + +{ + int i; + + if (current_type != NULL) + for (i=0;i<=current_type->type_commands.last_command;i++) { + if (strcmp (current_type->type_commands.names [i],text)==0) { + wprintw (show_pad,"%s - %s\n",text,current_type->type_commands.descriptions [i]); + refresh_show_pad ();return; + } + } + + for (i=0;i<=ext2_commands.last_command;i++) { + if (strcmp (ext2_commands.names [i],text)==0) { + wprintw (show_pad,"%s - %s\n",text,ext2_commands.descriptions [i]); + refresh_show_pad ();return; + } + } + + for (i=0;i<=general_commands.last_command;i++) { + if (strcmp (general_commands.names [i],text)==0) { + wprintw (show_pad,"%s - %s\n",text,general_commands.descriptions [i]); + refresh_show_pad ();return; + } + } + + if (strcmp ("quit",text)==0) { + wprintw (show_pad,"quit - Exists EXT2ED"); + refresh_show_pad ();return; + } + + wprintw (show_pad,"Error - Command %s not available now\n",text); + refresh_show_pad ();return; +} + + + +void set_device (char *command_line) + +{ + char *ptr,new_device [80]; + + ptr=parse_word (command_line,new_device); + if (*ptr==0) { + wprintw (command_win,"Error - Device name not specified\n"); + refresh_command_win ();return; + } + parse_word (ptr,new_device); + check_mounted (new_device); + if (mounted && !AllowMountedRead) { + wprintw (command_win,"Error - Filesystem is mounted, aborting\n"); + wprintw (command_win,"You may wish to use the AllowMountedRead on configuration option\n"); + refresh_command_win ();return; + } + + if (mounted && AllowMountedRead) { + wprintw (command_win,"Warning - Filesystem is mounted. Displayed data may be unreliable.\n"); + refresh_command_win (); + } + + if (device_handle!=NULL) + fclose (device_handle); + + if ( (device_handle=fopen (new_device,"rb"))==NULL) { + wprintw (command_win,"Error - Can not open device %s\n",new_device);refresh_command_win (); + return; + } + else { + strcpy (device_name,new_device); + write_access=0; /* Write access disabled */ + current_type=NULL; /* There is no type now */ + remember_lifo.entries_count=0; /* Empty Object memory */ + free_user_commands (&ext2_commands); /* Free filesystem specific objects */ + free_struct_descriptors (); + if (!set_file_system_info ()) { /* Error while getting info --> abort */ + free_user_commands (&ext2_commands); + free_struct_descriptors (); + fclose (device_handle); + device_handle=NULL; /* Notice that our device is still not set up */ + device_offset=-1; + return; + } + if (*AlternateDescriptors) /* Check if user defined objects exist */ + set_struct_descriptors (AlternateDescriptors); + dispatch ("setoffset 0"); + dispatch ("help"); /* Show help screen */ + wprintw (command_win,"Device changed to %s",device_name);refresh_command_win (); + } +} + +void set_offset (char *command_line) + +{ + long mult=1; + long new_offset; + char *ptr,new_offset_buffer [80]; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + ptr=parse_word (command_line,new_offset_buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win (); + return; + } + + ptr=parse_word (ptr,new_offset_buffer); + + if (strcmp (new_offset_buffer,"block")==0) { + mult=file_system_info.block_size; + ptr=parse_word (ptr,new_offset_buffer); + } + + if (strcmp (new_offset_buffer,"type")==0) { + if (current_type==NULL) { + wprintw (command_win,"Error - No type set\n");refresh_command_win (); + return; + } + + mult=current_type->length; + ptr=parse_word (ptr,new_offset_buffer); + } + + if (*new_offset_buffer==0) { + wprintw (command_win,"Error - No offset specified\n");refresh_command_win (); + return; + } + + if (new_offset_buffer [0]=='+') { + if (device_offset==-1) { + wprintw (command_win,"Error - Select a fixed offset first\n");refresh_command_win (); + return; + } + new_offset=device_offset+atol (new_offset_buffer+1)*mult; + } + + else if (new_offset_buffer [0]=='-') { + if (device_offset==-1) { + wprintw (command_win,"Error - Select a fixed offset first\n");refresh_command_win (); + return; + } + new_offset=device_offset-atol (new_offset_buffer+1)*mult; + if (new_offset<0) new_offset=0; + } + + else + new_offset=atol (new_offset_buffer)*mult; + + if ( (fseek (device_handle,new_offset,SEEK_SET))==-1) { + wprintw (command_win,"Error - Failed to seek to offset %ld in device %s\n",new_offset,device_name); + refresh_command_win (); + return; + }; + device_offset=new_offset; + wprintw (command_win,"Device offset changed to %ld\n",device_offset);refresh_command_win (); + load_type_data (); + type_data.offset_in_block=0; +} + +void set_int(short len, void *ptr, char *name, char *value) +{ + char *char_ptr; + short *short_ptr; + long *long_ptr; + long v; + char *tmp; + + v = strtol(value, &tmp, 0); + if (*tmp) { + wprintw( command_win, "Bad value - %s\n", value); + return; + } + switch (len) { + case 1: + char_ptr = (char *) ptr; + *char_ptr = v; + break; + case 2: + short_ptr = (short *) ptr; + *short_ptr = v; + break; + case 4: + long_ptr = (long *) ptr; + *long_ptr = v; + break; + default: + wprintw (command_win, + "set_int: unsupported length: %d\n", len); + return; + } + wprintw (command_win, "Variable %s set to %s\n", + name, value); +} + +void set_uint(short len, void *ptr, char *name, char *value) +{ + unsigned char *char_ptr; + unsigned short *short_ptr; + unsigned long *long_ptr; + unsigned long v; + char *tmp; + + v = strtoul(value, &tmp, 0); + if (*tmp) { + wprintw( command_win, "Bad value - %s\n", value); + return; + } + switch (len) { + case 1: + char_ptr = (unsigned char *) ptr; + *char_ptr = v; + break; + case 2: + short_ptr = (unsigned short *) ptr; + *short_ptr = v; + break; + case 4: + long_ptr = (unsigned long *) ptr; + *long_ptr = v; + break; + default: + wprintw (command_win, + "set_uint: unsupported length: %d\n", len); + return; + } + wprintw (command_win, "Variable %s set to %s\n", + name, value); +} + +void set_char(short len, void *ptr, char *name, char *value) +{ + if (strlen(value)+1 > len) { + wprintw( command_win, "Value %s too big for field\n", + name, len); + return; + } + memset(ptr, 0, len); + strcpy((char *) ptr, value); + wprintw (command_win, "Variable %s set to %s\n", + name, value); +} + + +void set (char *command_line) + +{ + unsigned short *int_ptr; + unsigned char *char_ptr; + unsigned long *long_ptr,offset=0; + int i,len, found=0; + char *ptr,buffer [80],variable [80],value [80]; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + if (current_type==NULL) { + hex_set (command_line); + return; + } + + ptr=parse_word (command_line,buffer); + if (ptr==NULL || *ptr==0) { + wprintw (command_win,"Error - Missing arguments\n");refresh_command_win (); + return; + } + parse_word (ptr,buffer); + ptr=strchr (buffer,'='); + if (ptr==NULL) { + wprintw (command_win,"Error - Bad syntax\n");refresh_command_win ();return; + } + strncpy (variable,buffer,ptr-buffer);variable [ptr-buffer]=0; + strcpy (value,++ptr); + + if (current_type==NULL) { + wprintw (command_win,"Sorry, not yet supported\n");refresh_command_win ();return; + } + + for (i=0;ifields_num && !found;i++) { + if (strcmp (current_type->field_names [i],variable)==0) { + found=1; + ptr=type_data.u.buffer+offset; + len = current_type->field_lengths [i]; + switch (current_type->field_types [i]) { + case FIELD_TYPE_INT: + set_int(len, ptr, variable, value); + break; + case FIELD_TYPE_UINT: + set_uint(len, ptr, variable, value); + break; + case FIELD_TYPE_CHAR: + set_char(len, ptr, variable, value); + break; + default: + wprintw (command_win, + "set: unhandled type %d\n", + current_type->field_types [i]); + break; + } + refresh_command_win (); + } + offset+=current_type->field_lengths [i]; + } + if (found) + dispatch ("show"); + else { + wprintw (command_win,"Error - Variable %s not found\n",variable); + refresh_command_win (); + } +} + +void hex_set (char *command_line) + +{ + unsigned char tmp; + char *ptr,buffer [80],*ch_ptr; + int mode=HEX; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win ();return; + } + + ptr=parse_word (ptr,buffer); + + if (strcasecmp (buffer,"text")==0) { + mode=TEXT; + strcpy (buffer,ptr); + } + + else if (strcasecmp (buffer,"hex")==0) { + mode=HEX; + ptr=parse_word (ptr,buffer); + } + + if (*buffer==0) { + wprintw (command_win,"Error - Data not specified\n");refresh_command_win ();return; + } + + if (mode==HEX) { + do { + tmp=(unsigned char) strtol (buffer,NULL,16); + type_data.u.buffer [type_data.offset_in_block]=tmp; + type_data.offset_in_block++; + ptr=parse_word (ptr,buffer); + if (type_data.offset_in_block==file_system_info.block_size) { + if (*ptr) { + wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n"); + refresh_command_win (); + } + type_data.offset_in_block--; + } + } while (*buffer) ; + } + + else { + ch_ptr=buffer; + while (*ch_ptr) { + tmp=(unsigned char) *ch_ptr++; + type_data.u.buffer [type_data.offset_in_block]=tmp; + type_data.offset_in_block++; + if (type_data.offset_in_block==file_system_info.block_size) { + if (*ch_ptr) { + wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n"); + refresh_command_win (); + } + type_data.offset_in_block--; + } + } + } + + strcpy (buffer,"show");dispatch (buffer); +} + + + +void set_type (char *command_line) + +{ + struct struct_descriptor *descriptor_ptr; + char *ptr,buffer [80],tmp_buffer [80]; + short found=0; + + if (!load_type_data ()) + return; + + ptr=parse_word (command_line,buffer); + parse_word (ptr,buffer); + + if (strcmp (buffer,"none")==0 || strcmp (buffer,"hex")==0) { + wprintw (command_win,"Data will be shown as hex dump\n");refresh_command_win (); + current_type=NULL; + sprintf (tmp_buffer,"show");dispatch (tmp_buffer); + return; + } + + descriptor_ptr=first_type; + while (descriptor_ptr!=NULL && !found) { + if (strcmp (descriptor_ptr->name,buffer)==0) + found=1; + else + descriptor_ptr=descriptor_ptr->next; + } + if (found) { + wprintw (command_win,"Structure type set to %s\n",buffer);refresh_command_win (); + current_type=descriptor_ptr; + sprintf (tmp_buffer,"show");dispatch (tmp_buffer); + } + else { + wprintw (command_win,"Error - %s is not a valid type\n",buffer);refresh_command_win (); + } +} + +void show_int(short len, void *ptr) +{ + long temp; + char *format; + + switch (len) { + case 1: + temp = *((char *) ptr); + format = "%3d (0x%02x)\n"; + break; + case 2: + temp = *((short *) ptr); + format = "%d (0x%x)\n"; + break; + case 4: + temp = *((long *) ptr); + format = "%d\n"; + break; + default: + wprintw (show_pad, "unimplemented\n"); + return; + } + wprintw(show_pad, format, temp, temp); +} + +void show_uint(short len, void *ptr) +{ + unsigned long temp; + char *format; + + switch (len) { + case 1: + temp = *((unsigned char *) ptr); + temp = temp & 0xFF; + format = "%3u (0x%02x)\n"; + break; + case 2: + temp = *((unsigned short *) ptr); + temp = temp & 0xFFFF; + format = "%u (0x%x)\n"; + break; + case 4: + temp = (unsigned long) *((unsigned long *) ptr); + format = "%u\n"; + break; + default: + wprintw (show_pad, "unimplemented\n"); + return; + } + wprintw(show_pad, format, temp, temp); +} + +void show_char(short len, void *ptr) +{ + unsigned char *cp = (unsigned char *) ptr; + unsigned char ch; + int i,j; + + wprintw(show_pad, "\""); + + for (i=0; i < len; i++) { + ch = *cp++; + if (ch == 0) { + for (j=i+1; j < len; j++) + if (cp[j-i]) + break; + if (j == len) + break; + } + if (ch > 128) { + wprintw(show_pad, "M-"); + ch -= 128; + } + if ((ch < 32) || (ch == 0x7f)) { + wprintw(show_pad, "^"); + ch ^= 0x40; /* ^@, ^A, ^B; ^? for DEL */ + } + wprintw(show_pad, "%c", ch); + } + + wprintw(show_pad, "\"\n"); +} + + + +void show (char *command_line) + +{ + unsigned int i,l,len,temp_int; + unsigned long offset=0,temp_long; + unsigned char temp_char,*ch_ptr; + void *ptr; + + if (device_handle==NULL) + return; + + show_pad_info.line=0; + + if (current_type==NULL) { + wmove (show_pad,0,0); + ch_ptr=type_data.u.buffer; + for (l=0;l=' ' && ch_ptr [i]<='z') + wprintw (show_pad,"%c",ch_ptr [i]); + else + wprintw (show_pad,"."); + if (type_data.offset_in_block==offset+i) + wattrset (show_pad,A_NORMAL); + } + wprintw (show_pad," "); + for (i=0;i<16;i++) { + if (type_data.offset_in_block==offset+i) + wattrset (show_pad,A_REVERSE); + + wprintw (show_pad,"%02x",ch_ptr [i]); + + if (type_data.offset_in_block==offset+i) { + wattrset (show_pad,A_NORMAL); + show_pad_info.line=l-l % show_pad_info.display_lines; + } + + wprintw (show_pad," "); + } + wprintw (show_pad,"\n"); + offset+=16; + ch_ptr+=16; + } + show_pad_info.max_line=l-1;show_pad_info.max_col=COLS-1; + refresh_show_pad ();show_info (); + } + else { + wmove (show_pad,0,0);l=0; + for (i=0;ifields_num;i++) { + wprintw (show_pad,"%-20s = ",current_type->field_names [i]); + ptr=type_data.u.buffer+offset; + len = current_type->field_lengths[i]; + switch (current_type->field_types[i]) { + case FIELD_TYPE_INT: + show_int(len, ptr); + break; + case FIELD_TYPE_UINT: + show_uint(len, ptr); + break; + case FIELD_TYPE_CHAR: + show_char(len, ptr); + break; + default: + wprintw (show_pad, "unimplemented\n"); + break; + } + offset+=len; + l++; + } + current_type->length=offset; + show_pad_info.max_line=l-1; + refresh_show_pad ();show_info (); + } +} + +void next (char *command_line) + +{ + long offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + if (current_type!=NULL) { + sprintf (buffer,"setoffset type +%ld",offset); + dispatch (buffer); + return; + } + + if (type_data.offset_in_block+offset < file_system_info.block_size) { + type_data.offset_in_block+=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void prev (char *command_line) + +{ + long offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + if (current_type!=NULL) { + sprintf (buffer,"setoffset type -%ld",offset); + dispatch (buffer); + return; + } + + if (type_data.offset_in_block-offset >= 0) { + type_data.offset_in_block-=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void pgdn (char *commnad_line) + +{ + show_pad_info.line+=show_pad_info.display_lines; + refresh_show_pad ();refresh_show_win (); +} + +void pgup (char *command_line) + +{ + show_pad_info.line-=show_pad_info.display_lines; + refresh_show_pad ();refresh_show_win (); +} + +void redraw (char *command_line) + +{ + redraw_all (); + dispatch ("show"); +} + +void remember (char *command_line) + +{ + long entry_num; + char *ptr,buffer [80]; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win (); + return; + } + + ptr=parse_word (ptr,buffer); + + entry_num=remember_lifo.entries_count++; + if (entry_num>REMEMBER_COUNT-1) { + entry_num=0; + remember_lifo.entries_count--; + } + + remember_lifo.offset [entry_num]=device_offset; + remember_lifo.type [entry_num]=current_type; + strcpy (remember_lifo.name [entry_num],buffer); + + if (current_type!=NULL) + wprintw (command_win,"Object %s in Offset %ld remembered as %s\n",current_type->name,device_offset,buffer); + else + wprintw (command_win,"Offset %ld remembered as %s\n",device_offset,buffer); + + refresh_command_win (); +} + +void recall (char *command_line) + +{ + char *ptr,buffer [80]; + long entry_num; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win (); + return; + } + + ptr=parse_word (ptr,buffer); + + + for (entry_num=remember_lifo.entries_count-1;entry_num>=0;entry_num--) { + if (strcmp (remember_lifo.name [entry_num],buffer)==0) + break; + } + + if (entry_num==-1) { + wprintw (command_win,"Error - Can not recall %s\n",buffer);refresh_command_win (); + return; + } + + sprintf (buffer,"setoffset %ld",remember_lifo.offset [entry_num]);dispatch (buffer); + if (remember_lifo.type [entry_num] != NULL) { + sprintf (buffer,"settype %s",remember_lifo.type [entry_num]->name);dispatch (buffer); + } + + else { + sprintf (buffer,"settype none");dispatch (buffer); + } + + wprintw (command_win,"Object %s in Offset %ld recalled\n",current_type->name,device_offset); + refresh_command_win (); +} + +void enable_write (char *command_line) + +{ + FILE *fp; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + if (!AllowChanges) { + wprintw (command_win,"Sorry, write access is not allowed\n"); + return; + } + + if (mounted) { + wprintw (command_win,"Error - Filesystem is mounted\n"); + return; + } + + if ( (fp=fopen (device_name,"r+b"))==NULL) { + wprintw (command_win,"Error - Can not open device %s for reading and writing\n",device_name);refresh_command_win (); + return; + } + fclose (device_handle); + device_handle=fp;write_access=1; + wprintw (command_win,"Write access enabled - Be careful\n");refresh_command_win (); +} + +void disable_write (char *command_line) + +{ + FILE *fp; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + if ( (fp=fopen (device_name,"rb"))==NULL) { + wprintw (command_win,"Error - Can not open device %s\n",device_name);refresh_command_win (); + return; + } + + fclose (device_handle); + device_handle=fp;write_access=0; + wprintw (command_win,"Write access disabled\n");refresh_command_win (); +} + +void write_data (char *command_line) + +{ + write_type_data (); +} diff --git a/ext2ed/group_com.c b/ext2ed/group_com.c new file mode 100644 index 0000000..aaed16e --- /dev/null +++ b/ext2ed/group_com.c @@ -0,0 +1,183 @@ +/* + +/usr/src/ext2ed/group_com.c + +A part of the extended file system 2 disk editor. + +General user commands + +First written on: April 17 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include + +#include "ext2ed.h" + +void type_ext2_group_desc___next (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",group_info.group_num+entry_offset); + dispatch (buffer); +} + +void type_ext2_group_desc___prev (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",group_info.group_num-entry_offset); + dispatch (buffer); +} + +void type_ext2_group_desc___entry (char *command_line) + +{ + long group_num; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + group_num=atol (buffer); + + if (group_num < 0 || group_num >= file_system_info.groups_count) { + wprintw (command_win,"Error - Entry number out of bounds\n");refresh_command_win ();return; + } + + device_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer); + strcpy (buffer,"show");dispatch (buffer); + group_info.group_num=group_num; +} + + +void type_ext2_group_desc___gocopy (char *command_line) + +{ + unsigned long copy_num,offset; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + copy_num=atol (buffer); + + offset=file_system_info.first_group_desc_offset+copy_num*file_system_info.super_block.s_blocks_per_group*file_system_info.block_size; + + if (offset > file_system_info.file_system_size) { + wprintw (command_win,"Error - Copy number out of bounds\n");refresh_command_win ();return; + } + + group_info.copy_num=copy_num; + device_offset=offset+group_info.group_num*sizeof (struct ext2_group_desc); + + sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer); + strcpy (buffer,"show");dispatch (buffer); +} + + +void type_ext2_group_desc___show (char *command_line) + +{ + long group_num,temp; + + temp=(device_offset-file_system_info.first_group_desc_offset) % (file_system_info.super_block.s_blocks_per_group*file_system_info.block_size); + group_num=temp/sizeof (struct ext2_group_desc); + + show (command_line); + + wmove (show_win,1,0);wprintw (show_win,"\n");wmove (show_win,2,0); + wprintw (show_win,"Group %ld of %ld ",group_num,file_system_info.groups_count-1); + wprintw (show_win,"in copy %ld ",group_info.copy_num); + if (group_info.copy_num==0) wprintw (show_win,"(Main copy)"); + wprintw (show_win,"\n");refresh_show_win (); + + if (group_num==0) { + wprintw (command_win,"Reached first group descriptor\n"); + wrefresh (command_win); + } + + if (group_num==file_system_info.groups_count-1) { + wprintw (command_win,"Reached last group descriptor\n"); + wrefresh (command_win); + } +} + +void type_ext2_group_desc___inode (char *command_line) + +{ + long inode_offset; + char buffer [80]; + + inode_offset=type_data.u.t_ext2_group_desc.bg_inode_table; + sprintf (buffer,"setoffset block %ld",inode_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_inode");dispatch (buffer); +} + +void type_ext2_group_desc___blockbitmap (char *command_line) + +{ + long block_bitmap_offset; + char buffer [80]; + + block_bitmap_info.entry_num=0; + block_bitmap_info.group_num=group_info.group_num; + + block_bitmap_offset=type_data.u.t_ext2_group_desc.bg_block_bitmap; + sprintf (buffer,"setoffset block %ld",block_bitmap_offset);dispatch (buffer); + sprintf (buffer,"settype block_bitmap");dispatch (buffer); +} + +void type_ext2_group_desc___inodebitmap (char *command_line) + +{ + long inode_bitmap_offset; + char buffer [80]; + + inode_bitmap_info.entry_num=0; + inode_bitmap_info.group_num=group_info.group_num; + + inode_bitmap_offset=type_data.u.t_ext2_group_desc.bg_inode_bitmap; + sprintf (buffer,"setoffset block %ld",inode_bitmap_offset);dispatch (buffer); + sprintf (buffer,"settype inode_bitmap");dispatch (buffer); +} + +void type_ext2_group_desc___setactivecopy (char *command_line) + +{ + struct ext2_group_desc gd; + + gd=type_data.u.t_ext2_group_desc; + dispatch ("gocopy 0"); + type_data.u.t_ext2_group_desc=gd; + dispatch ("show"); +} diff --git a/ext2ed/init.c b/ext2ed/init.c new file mode 100644 index 0000000..4e58431 --- /dev/null +++ b/ext2ed/init.c @@ -0,0 +1,633 @@ +/* + +/usr/src/ext2ed/init.c + +A part of the extended file system 2 disk editor. + +-------------------------------- +Various initialization routines. +-------------------------------- + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include +#ifdef HAVE_READLINE +#include +#endif +#include +#include + +#include +#include +#include + +#include "ext2ed.h" + +char lines_s [80],cols_s [80]; + +void signal_handler (void); + +void prepare_to_close (void) + +{ + close_windows (); + if (device_handle!=NULL) + fclose (device_handle); + free_user_commands (&general_commands); + free_user_commands (&ext2_commands); + free_struct_descriptors (); +} + +int init (void) + +{ + printf ("Initializing ...\n"); + + if (!process_configuration_file ()) { + fprintf (stderr,"Error - Unable to complete configuration. Quitting.\n"); + return (0); + }; + + general_commands.last_command=-1; /* No commands whatsoever meanwhile */ + ext2_commands.last_command=-1; + add_general_commands (); /* Add the general commands, available always */ + device_handle=NULL; /* Notice that our device is still not set up */ + device_offset=-1; + current_type=NULL; /* No filesystem specific types yet */ + + remember_lifo.entries_count=0; /* Object memory is empty */ + + init_windows (); /* Initialize the NCURSES interface */ + init_readline (); /* Initialize the READLINE interface */ + init_signals (); /* Initialize the signal handlers */ + write_access=0; /* Write access disabled */ + + strcpy (last_command_line,"help"); /* Show the help screen to the user */ + dispatch ("help"); + return (1); /* Success */ +} + +void add_general_commands (void) + +{ + add_user_command (&general_commands,"help","EXT2ED help system",help); + add_user_command (&general_commands,"set","Changes a variable in the current object",set); + add_user_command (&general_commands,"setdevice","Selects the filesystem block device (e.g. /dev/hda1)",set_device); + add_user_command (&general_commands,"setoffset","Moves asynchronously in the filesystem",set_offset); + add_user_command (&general_commands,"settype","Tells EXT2ED how to interpret the current object",set_type); + add_user_command (&general_commands,"show","Displays the current object",show); + add_user_command (&general_commands,"pgup","Scrolls data one page up",pgup); + add_user_command (&general_commands,"pgdn","Scrolls data one page down",pgdn); + add_user_command (&general_commands,"redraw","Redisplay the screen",redraw); + add_user_command (&general_commands,"remember","Saves the current position and data information",remember); + add_user_command (&general_commands,"recall","Gets back to the saved object position",recall); + add_user_command (&general_commands,"enablewrite","Enters Read/Write mode - Allows changing the filesystem",enable_write); + add_user_command (&general_commands,"disablewrite","Enters read only mode",disable_write); + add_user_command (&general_commands,"writedata","Write data back to disk",write_data); + add_user_command (&general_commands,"next","Moves to the next byte in hex mode",next); + add_user_command (&general_commands,"prev","Moves to the previous byte in hex mode",prev); +} + +void add_ext2_general_commands (void) + +{ + add_user_command (&ext2_commands,"super","Moves to the superblock of the filesystem",type_ext2___super); + add_user_command (&ext2_commands,"group","Moves to the first group descriptor",type_ext2___group); + add_user_command (&ext2_commands,"cd","Moves to the directory specified",type_ext2___cd); +} + +int set_struct_descriptors (char *file_name) + +{ + FILE *fp; + char current_line [500],current_word [50],*ch; + char variable_name [50],variable_type [20]; + struct struct_descriptor *current_descriptor; + + if ( (fp=fopen (file_name,"rt"))==NULL) { + wprintw (command_win,"Error - Failed to open descriptors file %s\n",file_name); + refresh_command_win (); return (0); + }; + + while (!feof (fp)) { + fgets (current_line,500,fp); + if (feof (fp)) break; + ch=parse_word (current_line,current_word); + if (strcmp (current_word,"struct")==0) { + ch=parse_word (ch,current_word); + current_descriptor=add_new_descriptor (current_word); + + while (strchr (current_line,'{')==NULL) { + fgets (current_line,500,fp); + if (feof (fp)) break; + }; + if (feof (fp)) break; + + fgets (current_line,500,fp); + + while (strchr (current_line,'}')==NULL) { + while (strchr (current_line,';')==NULL) { + fgets (current_line,500,fp); + if (strchr (current_line,'}')!=NULL) break; + }; + if (strchr (current_line,'}') !=NULL) break; + ch=parse_word (current_line,variable_type); + ch=parse_word (ch,variable_name); + while (variable_name [strlen (variable_name)-1]!=';') { + strcpy (variable_type,variable_name); + ch=parse_word (ch,variable_name); + }; + variable_name [strlen (variable_name)-1]=0; + add_new_variable (current_descriptor,variable_type,variable_name); + fgets (current_line,500,fp); + }; + }; + }; + + fclose (fp); + return (1); +} + +void free_struct_descriptors (void) + +{ + struct struct_descriptor *ptr,*next; + + ptr=first_type; + while (ptr!=NULL) { + next=ptr->next; + free_user_commands (&ptr->type_commands); + free (ptr); + ptr=next; + } + first_type=last_type=current_type=NULL; +} + +void free_user_commands (struct struct_commands *ptr) + +{ + int i; + + for (i=0;i<=ptr->last_command;i++) { + free (ptr->names [i]); + free (ptr->descriptions [i]); + } + + ptr->last_command=-1; +} + +struct struct_descriptor *add_new_descriptor (char *name) + +{ + struct struct_descriptor *ptr; + + ptr = malloc (sizeof (struct struct_descriptor)); + if (ptr == NULL) { + printf ("Error - Can not allocate memory - Quitting\n"); + exit (1); + } + memset(ptr, 0, sizeof(struct struct_descriptor)); + ptr->prev = ptr->next = NULL; + strcpy (ptr->name,name); + ptr->length=0; + ptr->fields_num=0; + if (first_type==NULL) { + first_type = last_type = ptr; + } else { + ptr->prev = last_type; last_type->next = ptr; last_type=ptr; + } + ptr->type_commands.last_command=-1; + fill_type_commands (ptr); + return (ptr); +} + +struct type_table { + char *name; + int field_type; + int len; +}; + +struct type_table type_table[] = { + { "long", FIELD_TYPE_INT, 4 }, + { "short", FIELD_TYPE_INT, 2 }, + { "char", FIELD_TYPE_CHAR, 1 }, + { "__u32", FIELD_TYPE_UINT, 4 }, + { "__s32", FIELD_TYPE_INT, 4 }, + { "__u16", FIELD_TYPE_UINT, 2 }, + { "__s16", FIELD_TYPE_INT, 2 }, + { "__u8", FIELD_TYPE_UINT, 1 }, + { "__s8", FIELD_TYPE_INT, 1 }, + { 0, 0, 0 } +}; + +void add_new_variable (struct struct_descriptor *ptr,char *v_type,char *v_name) + +{ + short len=1; + char field_type=FIELD_TYPE_INT; + struct type_table *p; + + strcpy (ptr->field_names [ptr->fields_num],v_name); + ptr->field_positions [ptr->fields_num]=ptr->length; + + for (p = type_table; p->name; p++) { + if (strcmp(v_type, p->name) == 0) { + len = p->len; + field_type = p->field_type; + break; + } + } + if (p->name == 0) { + if (strncmp(v_type, "char[", 5) == 0) { + len = atoi(v_type+5); + field_type = FIELD_TYPE_CHAR; + } else { + printf("Unknown type %s for field %s\n", v_type, v_name); + exit(1); + } + } + + ptr->field_lengths [ptr->fields_num] = len; + ptr->field_types [ptr->fields_num] = field_type; + + ptr->length+=len; + ptr->fields_num++; +} + +void fill_type_commands (struct struct_descriptor *ptr) + +/* + +Set specific type user commands. + +*/ + +{ + + if (strcmp ((ptr->name),"file")==0) { + add_user_command (&ptr->type_commands,"show","Shows file data",type_file___show); + add_user_command (&ptr->type_commands,"inode","Returns to the inode of the current file",type_file___inode); + add_user_command (&ptr->type_commands,"display","Specifies data format - text or hex",type_file___display); + add_user_command (&ptr->type_commands,"next","Pass to next byte",type_file___next); + add_user_command (&ptr->type_commands,"prev","Pass to the previous byte",type_file___prev); + add_user_command (&ptr->type_commands,"offset","Pass to a specified byte in the current block",type_file___offset); + add_user_command (&ptr->type_commands,"nextblock","Pass to next file block",type_file___nextblock); + add_user_command (&ptr->type_commands,"prevblock","Pass to the previous file block",type_file___prevblock); + add_user_command (&ptr->type_commands,"block","Specify which file block to edit",type_file___block); + add_user_command (&ptr->type_commands,"remember","Saves the file\'s inode position for later reference",type_file___remember); + add_user_command (&ptr->type_commands,"set","Sets the current byte",type_file___set); + add_user_command (&ptr->type_commands,"writedata","Writes the current block to the disk",type_file___writedata); + } + + if (strcmp ((ptr->name),"ext2_inode")==0) { + add_user_command (&ptr->type_commands,"show","Shows inode data",type_ext2_inode___show); + add_user_command (&ptr->type_commands,"next","Move to next inode in current block group",type_ext2_inode___next); + add_user_command (&ptr->type_commands,"prev","Move to next inode in current block group",type_ext2_inode___prev); + add_user_command (&ptr->type_commands,"group","Move to the group descriptors of the current inode table",type_ext2_inode___group); + add_user_command (&ptr->type_commands,"entry","Move to a specified entry in the current inode table",type_ext2_inode___entry); + add_user_command (&ptr->type_commands,"file","Display file data of the current inode",type_ext2_inode___file); + add_user_command (&ptr->type_commands,"dir","Display directory data of the current inode",type_ext2_inode___dir); + } + + if (strcmp ((ptr->name),"dir")==0) { + add_user_command (&ptr->type_commands,"show","Shows current directory data",type_dir___show); + add_user_command (&ptr->type_commands,"inode","Returns to the inode of the current directory",type_dir___inode); + add_user_command (&ptr->type_commands,"next","Pass to the next directory entry",type_dir___next); + add_user_command (&ptr->type_commands,"prev","Pass to the previous directory entry",type_dir___prev); + add_user_command (&ptr->type_commands,"followinode","Follows the inode specified in this directory entry",type_dir___followinode); + add_user_command (&ptr->type_commands,"remember","Remember the inode of the current directory entry",type_dir___remember); + add_user_command (&ptr->type_commands,"cd","Changes directory relative to the current directory",type_dir___cd); + add_user_command (&ptr->type_commands,"entry","Moves to a specified entry in the current directory",type_dir___entry); + add_user_command (&ptr->type_commands,"writedata","Writes the current entry to the disk",type_dir___writedata); + add_user_command (&ptr->type_commands,"set","Changes a variable in the current directory entry",type_dir___set); + } + + if (strcmp ((ptr->name),"ext2_super_block")==0) { + add_user_command (&ptr->type_commands,"show","Displays the super block data",type_ext2_super_block___show); + add_user_command (&ptr->type_commands,"gocopy","Move to another backup copy of the superblock",type_ext2_super_block___gocopy); + add_user_command (&ptr->type_commands,"setactivecopy","Copies the current superblock to the main superblock",type_ext2_super_block___setactivecopy); + } + + if (strcmp ((ptr->name),"ext2_group_desc")==0) { + add_user_command (&ptr->type_commands,"next","Pass to the next block group descriptor",type_ext2_group_desc___next); + add_user_command (&ptr->type_commands,"prev","Pass to the previous group descriptor",type_ext2_group_desc___prev); + add_user_command (&ptr->type_commands,"entry","Pass to a specific group descriptor",type_ext2_group_desc___entry); + add_user_command (&ptr->type_commands,"show","Shows the current group descriptor",type_ext2_group_desc___show); + add_user_command (&ptr->type_commands,"inode","Pass to the inode table of the current group block",type_ext2_group_desc___inode); + add_user_command (&ptr->type_commands,"gocopy","Move to another backup copy of the group descriptor",type_ext2_group_desc___gocopy); + add_user_command (&ptr->type_commands,"blockbitmap","Show the block allocation bitmap of the current group block",type_ext2_group_desc___blockbitmap); + add_user_command (&ptr->type_commands,"inodebitmap","Show the inode allocation bitmap of the current group block",type_ext2_group_desc___inodebitmap); + add_user_command (&ptr->type_commands,"setactivecopy","Copies the current group descriptor to the main table",type_ext2_super_block___setactivecopy); + } + + if (strcmp ((ptr->name),"block_bitmap")==0) { + add_user_command (&ptr->type_commands,"show","Displays the block allocation bitmap",type_ext2_block_bitmap___show); + add_user_command (&ptr->type_commands,"entry","Moves to a specific bit",type_ext2_block_bitmap___entry); + add_user_command (&ptr->type_commands,"next","Moves to the next bit",type_ext2_block_bitmap___next); + add_user_command (&ptr->type_commands,"prev","Moves to the previous bit",type_ext2_block_bitmap___prev); + add_user_command (&ptr->type_commands,"allocate","Allocates the current block",type_ext2_block_bitmap___allocate); + add_user_command (&ptr->type_commands,"deallocate","Deallocates the current block",type_ext2_block_bitmap___deallocate); + } + + if (strcmp ((ptr->name),"inode_bitmap")==0) { + add_user_command (&ptr->type_commands,"show","Displays the inode allocation bitmap",type_ext2_inode_bitmap___show); + add_user_command (&ptr->type_commands,"entry","Moves to a specific bit",type_ext2_inode_bitmap___entry); + add_user_command (&ptr->type_commands,"next","Moves to the next bit",type_ext2_inode_bitmap___next); + add_user_command (&ptr->type_commands,"prev","Moves to the previous bit",type_ext2_inode_bitmap___prev); + add_user_command (&ptr->type_commands,"allocate","Allocates the current inode",type_ext2_inode_bitmap___allocate); + add_user_command (&ptr->type_commands,"deallocate","Deallocates the current inode",type_ext2_inode_bitmap___deallocate); + } + +} + +void add_user_command (struct struct_commands *ptr,char *name,char *description,PF callback) + +{ + int num; + + num=ptr->last_command; + if (num+1==MAX_COMMANDS_NUM) { + printf ("Internal Error - Can't add command %s\n",name); + return; + } + + ptr->last_command=++num; + + ptr->names [num]=(char *) malloc (strlen (name)+1); + strcpy (ptr->names [num],name); + + if (*description!=0) { + ptr->descriptions [num]=(char *) malloc (strlen (description)+1); + strcpy (ptr->descriptions [num],description); + } + + ptr->callback [num]=callback; +} + +int set_file_system_info (void) + +{ + int ext2_detected=0; + struct ext2_super_block *sb; + + file_system_info.super_block_offset=1024; + file_system_info.file_system_size=DefaultTotalBlocks*DefaultBlockSize; + + low_read ((char *) &file_system_info.super_block,sizeof (struct ext2_super_block),file_system_info.super_block_offset); + + sb=&file_system_info.super_block; + + if (sb->s_magic == EXT2_SUPER_MAGIC) + ext2_detected=1; + + if (ext2_detected) + wprintw (command_win,"Detected extended 2 file system on device %s\n",device_name); + else + wprintw (command_win,"Warning - Extended 2 filesystem not detected on device %s\n",device_name); + + if (!ext2_detected && !ForceExt2) + wprintw (command_win,"You may wish to use the configuration option ForceExt2 on\n"); + + if (ForceExt2 && !ext2_detected) + wprintw (command_win,"Forcing extended 2 filesystem\n"); + + if (ForceDefault || !ext2_detected) + wprintw (command_win,"Forcing default parameters\n"); + + refresh_command_win (); + + if (ext2_detected || ForceExt2) { + add_ext2_general_commands (); + if (!set_struct_descriptors (Ext2Descriptors)) + return (0); + } + + if (!ForceDefault && ext2_detected) { + + file_system_info.block_size=EXT2_MIN_BLOCK_SIZE << sb->s_log_block_size; + if (file_system_info.block_size == EXT2_MIN_BLOCK_SIZE) + file_system_info.first_group_desc_offset=2*EXT2_MIN_BLOCK_SIZE; + else + file_system_info.first_group_desc_offset=file_system_info.block_size; + file_system_info.groups_count = ext2fs_div64_ceil(ext2fs_blocks_count(sb), + sb->s_blocks_per_group); + + file_system_info.inodes_per_block=file_system_info.block_size/sizeof (struct ext2_inode); + file_system_info.blocks_per_group=sb->s_inodes_per_group/file_system_info.inodes_per_block; + file_system_info.no_blocks_in_group=sb->s_blocks_per_group; + file_system_info.file_system_size=(ext2fs_blocks_count(sb)-1)*file_system_info.block_size; + } + + else { + file_system_info.file_system_size=DefaultTotalBlocks*DefaultBlockSize; + file_system_info.block_size=DefaultBlockSize; + file_system_info.no_blocks_in_group=DefaultBlocksInGroup; + } + + if (file_system_info.file_system_size > 2147483647) { + wprintw (command_win,"Sorry, filesystems bigger than 2 GB are currently not supported\n"); + return (0); + } + return (1); +} + +void init_readline (void) + +{ +#ifdef HAVE_READLINE + rl_completion_entry_function=(Function *) complete_command; +#endif +} + +void init_signals (void) + +{ + signal (SIGWINCH, signal_SIGWINCH_handler); /* Catch SIGWINCH */ + signal (SIGTERM, signal_SIGTERM_handler); + signal (SIGSEGV, signal_SIGSEGV_handler); + +} + +void signal_SIGWINCH_handler (int sig_num) + +{ + redraw_request=1; /* We will handle it in main.c */ + + /* Reset signal handler */ + signal (SIGWINCH, signal_SIGWINCH_handler); + +} + +void signal_SIGTERM_handler (int sig_num) + +{ + prepare_to_close (); + printf ("Terminated due to signal %d\n",sig_num); + exit (1); +} + +void signal_SIGSEGV_handler (int sig_num) + +{ + prepare_to_close (); + printf ("Killed by signal %d!\n",sig_num); + exit (1); +} + +int process_configuration_file (void) + +{ + char buffer [300]; + char option [80],value [80]; + FILE *fp; + + strcpy (buffer, ROOT_SYSCONFDIR); + strcat (buffer,"/ext2ed.conf"); + + if ((fp=fopen (buffer,"rt"))==NULL) { + fprintf (stderr,"Error - Unable to open configuration file %s\n",buffer); + return (0); + } + + while (get_next_option (fp,option,value)) { + if (strcasecmp (option,"Ext2Descriptors")==0) { + strcpy (Ext2Descriptors,value); + } + + else if (strcasecmp (option,"AlternateDescriptors")==0) { + strcpy (AlternateDescriptors,value); + } + + else if (strcasecmp (option,"LogFile")==0) { + strcpy (LogFile,value); + } + + else if (strcasecmp (option,"LogChanges")==0) { + if (strcasecmp (value,"on")==0) + LogChanges = 1; + else if (strcasecmp (value,"off")==0) + LogChanges = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else if (strcasecmp (option,"AllowChanges")==0) { + if (strcasecmp (value,"on")==0) + AllowChanges = 1; + else if (strcasecmp (value,"off")==0) + AllowChanges = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else if (strcasecmp (option,"AllowMountedRead")==0) { + if (strcasecmp (value,"on")==0) + AllowMountedRead = 1; + else if (strcasecmp (value,"off")==0) + AllowMountedRead = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else if (strcasecmp (option,"ForceExt2")==0) { + if (strcasecmp (value,"on")==0) + ForceExt2 = 1; + else if (strcasecmp (value,"off")==0) + ForceExt2 = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else if (strcasecmp (option,"DefaultBlockSize")==0) { + DefaultBlockSize = atoi (value); + } + + else if (strcasecmp (option,"DefaultTotalBlocks")==0) { + DefaultTotalBlocks = strtoul (value,NULL,10); + } + + else if (strcasecmp (option,"DefaultBlocksInGroup")==0) { + DefaultBlocksInGroup = strtoul (value,NULL,10); + } + + else if (strcasecmp (option,"ForceDefault")==0) { + if (strcasecmp (value,"on")==0) + ForceDefault = 1; + else if (strcasecmp (value,"off")==0) + ForceDefault = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else { + fprintf (stderr,"Error - Unknown option: %s\n",option); + fclose (fp);return (0); + } + } + + printf ("Configuration completed\n"); + fclose (fp); + return (1); +} + +int get_next_option (FILE *fp,char *option,char *value) + +{ + char *ptr; + char buffer [600]; + + if (feof (fp)) return (0); + do{ + if (feof (fp)) return (0); + fgets (buffer,500,fp); + } while (buffer [0]=='#' || buffer [0]=='\n'); + + ptr=parse_word (buffer,option); + ptr=parse_word (ptr,value); + return (1); +} + +void check_mounted (char *name) + +{ + FILE *fp; + char *ptr; + char current_line [500],current_word [200]; + + mounted=0; + + if ( (fp=fopen ("/etc/mtab","rt"))==NULL) { + wprintw (command_win,"Error - Failed to open /etc/mtab. Assuming filesystem is mounted.\n"); + refresh_command_win ();mounted=1;return; + }; + + while (!feof (fp)) { + fgets (current_line,500,fp); + if (feof (fp)) break; + ptr=parse_word (current_line,current_word); + if (strcasecmp (current_word,name)==0) { + mounted=1;fclose (fp);return; + } + }; + + fclose (fp); + + return; +} diff --git a/ext2ed/inode_com.c b/ext2ed/inode_com.c new file mode 100644 index 0000000..2d3dd6d --- /dev/null +++ b/ext2ed/inode_com.c @@ -0,0 +1,437 @@ +/* + +/usr/src/ext2ed/inode_com.c + +A part of the extended file system 2 disk editor. + +Commands relevant to ext2_inode type. + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include +#include + +#include "ext2ed.h" + +void type_ext2_inode___prev (char *command_line) + +{ + + char *ptr,buffer [80]; + + long group_num,group_offset,entry_num,block_num,first_entry,last_entry; + long inode_num,mult=1; + struct ext2_group_desc desc; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + mult=atol (buffer); + } + + block_num=device_offset/file_system_info.block_size; + + group_num=inode_offset_to_group_num (device_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + + entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode); + + first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1; + inode_num=0; + + if (entry_num-mult+1>0) { + device_offset-=sizeof (struct ext2_inode)*mult; + entry_num-=mult; + + sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer); + strcpy (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Entry out of limits\n");refresh_command_win (); + } + + if (entry_num==0) { + wprintw (command_win,"Reached first inode in current group descriptor\n"); + refresh_command_win (); + } +} + +void type_ext2_inode___next (char *command_line) + +{ + + char *ptr,buffer [80]; + + long group_num,group_offset,entry_num,block_num,first_entry,last_entry; + long inode_num,mult=1; + struct ext2_group_desc desc; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + mult=atol (buffer); + } + + + block_num=device_offset/file_system_info.block_size; + + group_num=inode_offset_to_group_num (device_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + + entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode); + + first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1; + inode_num=0; + + if (entry_num+mult-1i_mode); + for (i=6;i>=0;i-=3) { + temp=inode_ptr->i_mode & 0x1ff; + temp=temp >> i; + if (temp & 4) + wprintw (show_pad,"r"); + else + wprintw (show_pad,"-"); + + if (temp & 2) + wprintw (show_pad,"w"); + else + wprintw (show_pad,"-"); + + if (temp & 1) + wprintw (show_pad,"x"); + else + wprintw (show_pad,"-"); + } + wmove (show_pad,3,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_atime)); + wmove (show_pad,4,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_ctime)); + wmove (show_pad,5,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_mtime)); + wmove (show_pad,6,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_dtime)); + + wmove (show_pad,10,40); + temp=inode_ptr->i_flags; + + if (temp & EXT2_SECRM_FL) + wprintw (show_pad,"s"); + else + wprintw (show_pad,"-"); + + + if (temp & EXT2_UNRM_FL) + wprintw (show_pad,"u"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_COMPR_FL) + wprintw (show_pad,"c"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_SYNC_FL) + wprintw (show_pad,"S"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_IMMUTABLE_FL) + wprintw (show_pad,"i"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_APPEND_FL) + wprintw (show_pad,"a"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_NODUMP_FL) + wprintw (show_pad,"d"); + else + wprintw (show_pad,"-"); + + refresh_show_pad (); + + wmove (show_win,1,0); + + wprintw (show_win,"Inode %ld of %ld. Entry %ld of %ld in group descriptor %ld.\n" + ,inode_num,file_system_info.super_block.s_inodes_count,entry_num,last_entry,group_num); + + wprintw (show_win,"Inode type: "); + + if (inode_num < EXT2_GOOD_OLD_FIRST_INO) { + switch (inode_num) { + case EXT2_BAD_INO: + wprintw (show_win,"Bad blocks inode - "); + break; + case EXT2_ROOT_INO: + wprintw (show_win,"Root inode - "); + break; + case EXT4_USR_QUOTA_INO: + wprintw (show_win,"User quota inode - "); + break; + case EXT4_GRP_QUOTA_INO: + wprintw (show_win,"Group quota inode - "); + break; + case EXT2_BOOT_LOADER_INO: + wprintw (show_win,"Boot loader inode - "); + break; + case EXT2_UNDEL_DIR_INO: + wprintw (show_win,"Undelete directory inode - "); + break; + default: + wprintw (show_win,"Reserved inode - "); + break; + } + } + if (type_data.u.t_ext2_inode.i_mode==0) + wprintw (show_win,"Free. "); + + if (S_ISREG (type_data.u.t_ext2_inode.i_mode)) + wprintw (show_win,"File. "); + + if (S_ISDIR (type_data.u.t_ext2_inode.i_mode)) + wprintw (show_win,"Directory. "); + + if (S_ISLNK (type_data.u.t_ext2_inode.i_mode)) { + wprintw (show_win,"Symbolic link. "); + wmove (show_pad,12,40); + + if (inode_ptr->i_size <= 60) + wprintw (show_pad,"-> %s",(char *) &type_data.u.t_ext2_inode.i_block [0]); + else + wprintw (show_pad,"Slow symbolic link\n"); + refresh_show_pad (); + } + + if (S_ISCHR (type_data.u.t_ext2_inode.i_mode)) + wprintw (show_win,"Character device."); + + if (S_ISBLK (type_data.u.t_ext2_inode.i_mode)) + wprintw (show_win,"Block device. "); + + wprintw (show_win,"\n");refresh_show_win (); + + if (entry_num==last_entry) { + wprintw (command_win,"Reached last inode in current group descriptor\n"); + refresh_command_win (); + } + + if (entry_num==first_entry) { + wprintw (command_win,"Reached first inode in current group descriptor\n"); + refresh_command_win (); + } + +} + +void type_ext2_inode___entry (char *command_line) + +{ + char *ptr,buffer [80]; + + long group_num,group_offset,entry_num,block_num,wanted_entry; + struct ext2_group_desc desc; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) return; + ptr=parse_word (ptr,buffer); + wanted_entry=atol (buffer); + + block_num=device_offset/file_system_info.block_size; + + group_num=inode_offset_to_group_num (device_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + + entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode); + + if (wanted_entry > entry_num) { + sprintf (buffer,"next %ld",wanted_entry-entry_num); + dispatch (buffer); + } + + else if (wanted_entry < entry_num) { + sprintf (buffer,"prev %ld",entry_num-wanted_entry); + dispatch (buffer); + } +} + +void type_ext2_inode___group (char *command_line) + +{ + char buffer [80]; + + long group_num,group_offset; + + group_num=inode_offset_to_group_num (device_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + sprintf (buffer,"setoffset %ld",group_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_group_desc");dispatch (buffer); +} + +void type_ext2_inode___file (char *command_line) + +{ + char buffer [80]; + + if (!S_ISREG (type_data.u.t_ext2_inode.i_mode)) { + wprintw (command_win,"Error - Inode type is not file\n");refresh_command_win (); + return; + } + + if (!init_file_info ()) { + wprintw (command_win,"Error - Unable to show file\n");refresh_command_win (); + return; + } + + sprintf (buffer,"settype file");dispatch (buffer); +} + +void type_ext2_inode___dir (char *command_line) + +{ + char buffer [80]; + + if (!S_ISDIR (type_data.u.t_ext2_inode.i_mode)) { + wprintw (command_win,"Error - Inode type is not directory\n");refresh_command_win (); + return; + } + +/* It is very important to init first_file_info first, as search_dir_entries relies on it */ + + if (!init_dir_info (&first_file_info)) { + wprintw (command_win,"Error - Unable to show directory\n");refresh_command_win (); + return; + } + + file_info=first_file_info; + + sprintf (buffer,"settype dir");dispatch (buffer); +} + +long inode_offset_to_group_num (long inode_offset) + +{ + int found=0; + struct ext2_group_desc desc; + + long block_num,group_offset,group_num; + + block_num=inode_offset/file_system_info.block_size; + + group_offset=file_system_info.first_group_desc_offset; + group_num=(group_offset-file_system_info.first_group_desc_offset)/sizeof (struct ext2_group_desc); + + while (!found && group_num>=0 && group_num=desc.bg_inode_table && block_num +#include +#include + +#include "ext2ed.h" + + +void type_ext2_inode_bitmap___entry (char *command_line) + +{ + unsigned long entry_num; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + entry_num=atol (buffer); + + if (entry_num >= file_system_info.super_block.s_inodes_per_group) { + wprintw (command_win,"Error - Entry number out of bounds\n");refresh_command_win ();return; + } + + inode_bitmap_info.entry_num=entry_num; + strcpy (buffer,"show");dispatch (buffer); +} + +void type_ext2_inode_bitmap___next (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",inode_bitmap_info.entry_num+entry_offset); + dispatch (buffer); +} + +void type_ext2_inode_bitmap___prev (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",inode_bitmap_info.entry_num-entry_offset); + dispatch (buffer); +} + +void type_ext2_inode_bitmap___allocate (char *command_line) + +{ + long entry_num,num=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + num=atol (buffer); + } + + entry_num=inode_bitmap_info.entry_num; + if (num > file_system_info.super_block.s_inodes_per_group-entry_num) { + wprintw (command_win,"Error - There aren't that much inodes in the group\n"); + refresh_command_win ();return; + } + + while (num) { + allocate_inode (entry_num); + num--;entry_num++; + } + + dispatch ("show"); +} + +void type_ext2_inode_bitmap___deallocate (char *command_line) + +{ + long entry_num,num=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + num=atol (buffer); + } + + entry_num=inode_bitmap_info.entry_num; + if (num > file_system_info.super_block.s_inodes_per_group-entry_num) { + wprintw (command_win,"Error - There aren't that much inodes in the group\n"); + refresh_command_win ();return; + } + + while (num) { + deallocate_inode (entry_num); + num--;entry_num++; + } + + dispatch ("show"); +} + + +void allocate_inode (long entry_num) + +{ + unsigned char bit_mask=1; + int byte_offset,j; + + byte_offset=entry_num/8; + for (j=0;j0;i--) + j*=2; + if ((*ptr) & j) + wprintw (show_win,"Allocated\n"); + else + wprintw (show_win,"Free\n"); + refresh_show_win (); +} diff --git a/ext2ed/main.c b/ext2ed/main.c new file mode 100644 index 0000000..9d33a8e --- /dev/null +++ b/ext2ed/main.c @@ -0,0 +1,548 @@ +/* + +/usr/src/ext2ed/main.c + +A part of the extended file system 2 disk editor. + +------------ +Main program +------------ + +This file mostly contains: + +1. A list of global variables used through the entire program. +2. The parser, which asks the command line from the user. +3. The dispatcher, which analyzes the command line and calls the appropriate handler function. +4. A command pattern matcher which is used along with the readline completion feature. +5. A function which tells the user that an internal error has occurred. + +First written on: March 30 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include +#include + +#ifdef HAVE_READLINE +#include +#include +#endif + +#ifdef HAVE_GETOPT_H +#include +#else +extern int optind; +extern char *optarg; +#endif + +#include "ext2ed.h" + +/* Global variables */ + +/* + +Configuration file options + +The following variables will be set by init.c to the values selected in the user configuration file. +They are initialized below to some logical defaults. + +*/ + + +char Ext2Descriptors [200]="ext2.descriptors"; /* The location of the ext2 filesystem object definition */ +char AlternateDescriptors [200]=""; /* We allow the user to define additional structures */ +char LogFile [200]="ext2ed.log"; /* The location of the log file - Each write will be logged there */ +int LogChanges=1; /* 1 enables logging, 0 disables logging */ +int AllowChanges=0; /* When set, the enablewrite command will fail */ +int AllowMountedRead=0; /* Behavior when trying to open a mounted filesystem read-only */ +int ForceExt2=0; /* When set, ext2 autodetection is overridden */ +int DefaultBlockSize=1024; +unsigned long DefaultTotalBlocks=2097151; +unsigned long DefaultBlocksInGroup=8192; /* The default values are used when an ext2 filesystem is not */ +int ForceDefault=0; /* detected, or ForceDefault is set */ + +char last_command_line [80]; /* A simple one command cache, in addition to the readline history */ + +char device_name [80]; /* The location of the filesystem */ +FILE *device_handle=NULL; /* This is passed to the fopen / fread ... commands */ +long device_offset; /* The current position in the filesystem */ + /* Note that we have a 2 GB limitation */ + +int mounted=0; /* This is set when we find that the filesystem is mounted */ + +struct struct_commands general_commands,ext2_commands; /* Used to define the general and ext2 commands */ +struct struct_descriptor *first_type,*last_type,*current_type; /* Used to access the double linked list */ +struct struct_type_data type_data; /* The current data is sometimes stored here */ +struct struct_file_system_info file_system_info; /* Essential information on the filesystem */ +struct struct_file_info file_info,first_file_info; /* Used by file_com.c to access files */ +struct struct_group_info group_info; /* Used by group_com.c */ +struct struct_super_info super_info; /* Used by super_com.c */ +struct struct_remember_lifo remember_lifo; /* A circular memory of objects */ +struct struct_block_bitmap_info block_bitmap_info; /* Used by blockbitmap_com.c */ +struct struct_inode_bitmap_info inode_bitmap_info; /* Used by inodebitmap_com.c */ + +int redraw_request=0; /* Is set by a signal handler to handle terminal */ + /* screen size change. */ + + +/* + * We just call the parser to get commands from the user. We quit when + * parser returns. + */ +int main (int argc, char **argv) +{ + int write_priv = 0; + int c; + char *buf; + + if (!init ()) + return (1); + while ((c = getopt (argc, argv, "w")) != EOF) { + switch (c) { + case 'w': + write_priv++; + break; + } + } + if (optind < argc) { + buf = malloc(strlen(argv[optind]) + 32); + if (!buf) { + fprintf(stderr, "Couldn't allocate filename buffer\n"); + exit(1); + } + strcpy(buf, "set_device "); + strcat(buf, argv[optind]); + set_device(buf); + free(buf); + if (write_priv) { + wprintw (command_win,"\n"); + enable_write("enable_write"); + } + } + parser (); /* Get and parse user commands */ + prepare_to_close(); /* Do some cleanup */ + printf("Quitting ...\n"); + return(0); +} + + +/* + * Read a character from the command window + */ +int command_read_key() +{ + int key = 0; + + while (!key) { + if (redraw_request) { + redraw_all(); + redraw_request=0; + } + key = wgetch(command_win); + switch (key) { + case 0x1A: + key = 0; + kill(getpid(), SIGTSTP); + break; + + case KEY_NPAGE: + pgdn(""); + refresh_command_win (); + break; + + case KEY_PPAGE: + pgup(""); + refresh_command_win (); + break; + case ERR: + key = 0; + break; + + case KEY_BACKSPACE: + key = '\b'; + } + if ((key < 32 && key != '\b' && key != '\n') || + (key > 127)) + key = 0; + } + return key; +} + +#ifdef HAVE_READLINE +int rl_getc_replacement(FILE *f) +{ + int key = command_read_key(); + + if (key == '\b') { + if (rl_point > 0) + wprintw(command_win, "\b \b"); + } else + wprintw(command_win, "%c", key); + return key; +} + +/* + * This function asks the user for a command and calls the dispatcher + * function, dispatch, to analyze it. We use the readline library + * function readline to read the command, hence all the usual readline + * keys are available. The new command is saved both in the + * readline's history and in our tiny one-command cache, so that only + * the enter key is needed to retype it. + */ +void parser (void) +{ + char *ptr,command_line [80]; + int quit=0; + +#if 0 + noecho(); + cbreak(); + keypad(command_win, 1); + wtimeout(command_win, 100); + + rl_getc_function = rl_getc_replacement; +#endif + + while (!quit) { + /* Terminal screen size has changed */ + if (redraw_request) { + redraw_all(); + redraw_request=0; + } + + wmove (command_win,0,0); + wclrtoeol (command_win); + wprintw (command_win,"ext2ed > "); + refresh_command_win (); + + /* + * The ncurses library optimizes cursor movement by + * keeping track of the cursor position. However, by + * using the readline library I'm breaking its + * assumptions. The double -1 arguments tell ncurses + * to disable cursor movement optimization this + * time. + */ + mvcur (-1,-1,LINES-COMMAND_WIN_LINES,0); + + /* echo (); */ + ptr=readline ("ext2ed > "); + /* noecho (); */ + + /* + * Readline allocated the buffer - Copy the string + * and free the allocated buffer + * XXX WHY??? + */ + strcpy (command_line,ptr); + free (ptr); + + if (*command_line != 0) + add_history (command_line); + + /* If only enter was pressed, recall the last command */ + if (*command_line==0) + strcpy (command_line,last_command_line); + + /* Emulate readline's actions for ncurses */ + mvcur (-1,-1,LINES-COMMAND_WIN_LINES,0); + werase (command_win); + wprintw (command_win,"ext2ed > "); + wprintw (command_win,command_line); + wprintw (command_win,"\n"); + refresh_command_win (); + + /* Save this command in our tiny cache */ + strcpy (last_command_line,command_line); + + /* And call dispatch to do the actual job */ + quit=dispatch (command_line); + } +} +#else +void read_line(char * foo) { + char * chptr = foo; + int ch; + int done = 0; + + while (!done && (ch = command_read_key())) { + switch (ch) { + case '\n': + done = 1; + break; + + case '\b': + if (chptr > foo) { + wprintw(command_win, "\b \b"); + chptr--; + } + break; + + default: + if (ch > 256) + break; + if (ch == '\n') break; + *chptr++ = ch; + wprintw(command_win, "%c", ch); + break; + } + } + *chptr = '\0'; +} + +void parser (void) +{ + char command_line [80]; + int quit=0; + + noecho(); + cbreak(); + wtimeout(command_win, 100); + keypad(command_win, 1); + + while (!quit) { + /* Terminal screen size has changed */ + if (redraw_request) { + redraw_all(); + redraw_request=0; + } + + wmove (command_win,0,0);wclrtoeol (command_win); + + wmove(command_win, 0, 0); + wprintw(command_win, "ext2ed > "); + read_line(command_line); + + /* If only enter was pressed, recall the last command */ + if (*command_line==0) + strcpy (command_line,last_command_line); + + mvcur (-1,-1,LINES-COMMAND_WIN_LINES + 1,0); + + strcpy (last_command_line,command_line); /* Save this command in our tiny cache */ + + /* And call dispatch to do the actual job */ + quit=dispatch (command_line); + } +} +#endif + + +/* + * This is a very important function. Its task is to receive a command + * name and link it to a C function. There are three types of commands: + * + * 1. General commands - Always available and accessed through + * general_commands. + * 2. Ext2 specific commands - Available when editing an ext2 + * filesystem, accessed through ext2_commands. + * 3. Type specific commands - Those are changing according to the + * current type. The global variable current_type points to the + * current object definition (of type struct_descriptor). In it, the + * struct_commands entry contains the type specific commands links. + * + * Overriding is an important feature - Much like in C++ : The same + * command name can dispatch to different functions. The overriding + * priority is 3,2,1; That is - A type specific command will always + * override a general command. This is used through the program to + * allow fine tuned operation. + * + * When an handling function is found, it is called along with the + * command line that was passed to us. The handling function is then + * free to interpret the arguments in its own style. + */ +int dispatch (char *command_line) +{ + int i,found=0; + + char command [80]; + + parse_word (command_line,command); + + if (strcasecmp (command,"quit")==0) return (1); + + /* 1. Search for type specific commands FIRST - Allows + overriding of a general command */ + + if (current_type != NULL) + for (i=0; + i<=current_type->type_commands.last_command && !found; + i++) { + if (strcasecmp (command,current_type->type_commands.names [i])==0) { + (*current_type->type_commands.callback [i]) (command_line); + found=1; + } + } + + /* 2. Now search for ext2 filesystem general commands */ + + if (!found) + for (i=0;i<=ext2_commands.last_command && !found;i++) { + if (strcasecmp (command,ext2_commands.names [i])==0) { + (*ext2_commands.callback [i]) (command_line); + found=1; + } + } + + + /* 3. If not found, search the general commands */ + + if (!found) + for (i=0;i<=general_commands.last_command && !found;i++) { + if (strcasecmp (command,general_commands.names [i])==0) { + (*general_commands.callback [i]) (command_line); + found=1; + } + } + + /* 4. If not found, issue an error message and return */ + + if (!found) { + wprintw (command_win,"Error: Unknown command\n"); + refresh_command_win (); + } + + return (0); +} + + +/* + * + * This function copies the next word in source to the variable dest, + * ignoring whitespaces. It returns a pointer to the next word in + * source. It is used to split the command line into command and arguments. + */ +char *parse_word (char *source,char *dest) +{ + char ch,*source_ptr,*target_ptr; + + if (*source==0) { + *dest=0; + return (source); + }; + + source_ptr=source;target_ptr=dest; + do { + ch=*source_ptr++; + } while (! (ch>' ' && ch<='z') && ch!=0); + + while (ch>' ' && ch<='z') { + *target_ptr++=ch; + ch=*source_ptr++; + } + + *target_ptr=0; + + source_ptr--; + do { + ch=*source_ptr++; + } while (! (ch>' ' && ch<='z') && ch!=0); + + return (--source_ptr); +} + +/* + * text is the partial command entered by the user; We assume that it + * is a part of a command - I didn't write code for smarter completion. + * + * The state variable is an index which tells us how many possible + * completions we already returned to readline. + * + * We return only one possible completion or (char *) NULL if there + * are no more completions. This function will be called by readline + * over and over until we tell it to stop. + * + * While scanning for possible completions, we use the same priority + * definition which was used in dispatch. + */ +#if HAVE_READLINE +char *complete_command (char *text,int state) +{ + int state_index=-1; + int i,len; + + len=strlen (text); + + /* Is the command type specific ? */ + + if (current_type != NULL) + for (i=0;i<=current_type->type_commands.last_command;i++) { + if (strncmp (current_type->type_commands.names [i],text,len)==0) { + state_index++; + if (state==state_index) { + return (dupstr (current_type->type_commands.names [i])); + } + } + } + + /* No, perhaps ext2 specific command then ? */ + + for (i=0;i<=ext2_commands.last_command;i++) { + if (strncmp (ext2_commands.names [i],text,len)==0) { + state_index++; + if (state==state_index) + return (dupstr (ext2_commands.names [i])); + } + } + + + /* Check for a general command */ + + for (i=0;i<=general_commands.last_command;i++) { + if (strncmp (general_commands.names [i],text,len)==0) { + state_index++; + if (state==state_index) + return (dupstr (general_commands.names [i])); + } + } + + /* quit is handled differently */ + + if (strncmp ("quit",text,len)==0) { + state_index++; + if (state==state_index) + return (dupstr ("quit")); + } + + /* No more completions */ + + return ((char *) NULL); +} +#endif + + +/* + * Nothing special - Just allocates enough space and copy the string. + */ +char *dupstr (char *src) +{ + char *ptr; + + ptr=(char *) malloc (strlen (src)+1); + if (!ptr) + return NULL; + strcpy (ptr,src); + return (ptr); +} + +#ifdef DEBUG +/* + * This function reports an internal error. It is almost not used. One + * place in which I do check for internal errors is disk.c. + * + * We just report the error, and try to continue ... + */ +void internal_error (char *description,char *source_name,char *function_name) +{ + wprintw (command_win,"Internal error - Found by source: %s.c , function: %s\n",source_name,function_name); + wprintw (command_win,"\t%s\n",description); + wprintw (command_win,"Press enter to (hopefully) continue\n"); + refresh_command_win ();getch ();werase (command_win); +} + +#endif diff --git a/ext2ed/super_com.c b/ext2ed/super_com.c new file mode 100644 index 0000000..a998970 --- /dev/null +++ b/ext2ed/super_com.c @@ -0,0 +1,156 @@ +/* + +/usr/src/ext2ed/super_com.c + +A part of the extended file system 2 disk editor. + +---------------------- +Handles the superblock +---------------------- + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include +#include + +#include "ext2ed.h" + +void type_ext2_super_block___show (char *command_line) + +{ + struct ext2_super_block *super; + super=&type_data.u.t_ext2_super_block; + + show (command_line); + + if (ext2fs_blocks_count(super) != 0) { + wmove (show_pad,2,40);wprintw (show_pad,"%2.2f%%",100*(float) ext2fs_r_blocks_count(super)/ (float) ext2fs_blocks_count(super)); + wmove (show_pad,3,40);wprintw (show_pad,"%2.2f%%",100*(float) ext2fs_free_blocks_count(super)/ (float) ext2fs_blocks_count(super)); + } + + if (super->s_inodes_count != 0) { + wmove (show_pad,4,40);wprintw (show_pad,"%2.2f%%",100*(float) super->s_free_inodes_count/ (float) super->s_inodes_count); + } + + wmove (show_pad,6,40); + switch (super->s_log_block_size) { + case 0: wprintw (show_pad,"1024 bytes");break; + case 1: wprintw (show_pad,"2048 bytes");break; + case 2: wprintw (show_pad,"4096 bytes");break; + } + wmove (show_pad,11,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_super_block.s_mtime)); + wmove (show_pad,12,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_super_block.s_wtime)); + wmove (show_pad,19,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_super_block.s_lastcheck)); + wmove (show_pad,15,40); + + switch (type_data.u.t_ext2_super_block.s_magic) { + case EXT2_SUPER_MAGIC: + wprintw (show_pad,"ext2 >= 0.2B"); + break; + case EXT2_PRE_02B_MAGIC: + wprintw (show_pad,"ext2 < 0.2B (not supported)"); + break; + default: + wprintw (show_pad,"Unknown"); + break; + } + + wmove (show_pad,16,40); + if (type_data.u.t_ext2_super_block.s_state & 0x1) + wprintw (show_pad,"clean "); + else + wprintw (show_pad,"not clean "); + + if (type_data.u.t_ext2_super_block.s_state & 0x2) + wprintw (show_pad,"with errors "); + else + wprintw (show_pad,"with no errors"); + + wmove (show_pad,17,40); + + switch (type_data.u.t_ext2_super_block.s_errors) { + case EXT2_ERRORS_CONTINUE: + wprintw (show_pad,"Continue"); + break; + case EXT2_ERRORS_RO: + wprintw (show_pad,"Remount read only"); + break; + case EXT2_ERRORS_PANIC: + wprintw (show_pad,"Issue kernel panic"); + break; + default: + wprintw (show_pad,"Unknown"); + break; + } + + wmove (show_pad,21,40); + + switch (type_data.u.t_ext2_super_block.s_creator_os) { + + case EXT2_OS_LINUX: + wprintw (show_pad,"Linux :-)"); + break; + + case EXT2_OS_HURD: + wprintw (show_pad,"Hurd"); + break; + + default: + wprintw (show_pad,"Unknown"); + break; + } + + refresh_show_pad (); + + wmove (show_win,1,0);wprintw (show_win,"\n");wmove (show_win,2,0); + wprintw (show_win,"Superblock copy %ld ",super_info.copy_num); + if (super_info.copy_num==0) + wprintw (show_win,"(main copy)"); + wprintw (show_win,"\n"); + refresh_show_win (); +} + +void type_ext2_super_block___gocopy (char *command_line) + +{ + unsigned long copy_num,offset; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + copy_num=atol (buffer); + + offset=file_system_info.super_block_offset+copy_num*file_system_info.no_blocks_in_group*file_system_info.block_size; + + if (offset > file_system_info.file_system_size) { + wprintw (command_win,"Error - Copy number out of bounds\n");refresh_command_win ();return; + } + + super_info.copy_num=copy_num; + device_offset=offset; + + sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer); + strcpy (buffer,"show");dispatch (buffer); +} + +void type_ext2_super_block___setactivecopy (char *command_line) + +{ + struct ext2_super_block sb; + + sb=type_data.u.t_ext2_super_block; + dispatch ("gocopy 0"); + type_data.u.t_ext2_super_block=sb; + dispatch ("show"); +} diff --git a/ext2ed/win.c b/ext2ed/win.c new file mode 100644 index 0000000..23d0da1 --- /dev/null +++ b/ext2ed/win.c @@ -0,0 +1,232 @@ +/* + +/usr/src/ext2ed/win.c + +A part of the extended file system 2 disk editor. + +-------------------------------------------------------- +Window management - Interfacing with the ncurses library +-------------------------------------------------------- + +First written on: April 17 1995 +Modified on : April 05 2001 Christian.Bac@int-evry.fr +it looks like readline does not like that initscr decides to set the tty to +noecho. + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include "config.h" +#include +#include +#include +#include +#include +#include + +#include "ext2ed.h" +#include "../version.h" + +struct struct_pad_info show_pad_info; +WINDOW *title_win,*show_win,*command_win,*mt_win1,*mt_win2,*show_pad; + +/* to remember configuration after initscr + * and modify it + */ +struct termios termioInit, termioCurrent; + +void draw_title_win (void) +{ + char title_string [128]; + + werase(title_win); + box (title_win,0,0); + sprintf (title_string,"EXT2ED - Extended-2 File System editor ver %s (%s)", E2FSPROGS_VERSION, E2FSPROGS_DATE); + wmove (title_win,TITLE_WIN_LINES/2,(COLS-strlen (title_string))/2); + wprintw (title_win,title_string); + wrefresh(title_win); +} + +void setup_show_win(void) +{ + wbkgdset (show_win,A_REVERSE);werase (show_win); + show_pad_info.line=0; + show_pad_info.col=0; + show_pad_info.display_lines=LINES-TITLE_WIN_LINES-SHOW_WIN_LINES-COMMAND_WIN_LINES-2; + show_pad_info.display_cols=COLS; + show_pad_info.max_line=show_pad_info.display_lines-1;show_pad_info.max_col=show_pad_info.display_cols-1; + show_pad_info.disable_output=0; +} + +void init_windows (void) +{ + initscr (); + tcgetattr(0,&termioInit); /* save initial config */ + termioCurrent = termioInit; + termioCurrent.c_lflag |= ECHO; /* set echo on */ + tcsetattr(0,TCSANOW,&termioCurrent); + + if (LINES show_pad_info.max_line-show_pad_info.display_lines+1) + show_pad_info.line=show_pad_info.max_line-show_pad_info.display_lines+1; + + if (show_pad_info.line < 0) + show_pad_info.line=0; + +#ifdef OLD_NCURSES + prefresh (show_pad,show_pad_info.line,show_pad_info.col,top,left,show_pad_info.display_lines-1,show_pad_info.display_cols-1); +#else + prefresh (show_pad,show_pad_info.line,show_pad_info.col,top,left,top+show_pad_info.display_lines-1,left+show_pad_info.display_cols-1); +#endif +} + +void refresh_command_win (void) +{ + wrefresh (command_win); +} + +void close_windows (void) +{ +// echo (); + tcsetattr(0,TCSANOW,&termioInit); + + delwin (title_win); + delwin (command_win); + delwin (show_win); + delwin (show_pad); + + endwin (); +} + +void show_info (void) +{ + int block_num,block_offset; + + block_num=device_offset/file_system_info.block_size; + block_offset=device_offset%file_system_info.block_size; + + wmove (show_win,0,0); + wprintw (show_win,"Offset %-3ld in block %ld. ",block_offset,block_num); + if (current_type != NULL) + wprintw (show_win,"Type: %s\n",current_type->name); + else + wprintw (show_win,"Type: %s\n","none"); + + refresh_show_win (); +} + + +void redraw_all (void) +{ + int min_lines = TITLE_WIN_LINES+SHOW_WIN_LINES+COMMAND_WIN_LINES+3; + struct winsize ws; + int save_col, save_lines; + + /* get the size of the terminal connected to stdout */ + ioctl(1, TIOCGWINSZ, &ws); + /* + * Do it again because GDB doesn't stop before the first ioctl + * call, we want an up-to-date size when we're + * single-stepping. + */ + if (ioctl(1, TIOCGWINSZ, &ws) == 0) { + if (ws.ws_row < min_lines) + ws.ws_row = min_lines; + if ((ws.ws_row != LINES) || (ws.ws_col != COLS)) { + wmove (show_win,2,COLS-18); + wclrtoeol(show_win); + wrefresh(show_win); + resizeterm(ws.ws_row, ws.ws_col); + wresize(title_win, TITLE_WIN_LINES,COLS); + wresize(show_win, SHOW_WIN_LINES,COLS); + wresize(command_win, COMMAND_WIN_LINES,COLS); + wresize(mt_win1, 1,COLS); + wresize(mt_win2, 1,COLS); + mvwin(mt_win2, LINES-COMMAND_WIN_LINES-1,0); + mvwin(command_win, LINES-COMMAND_WIN_LINES,0); + draw_title_win(); + show_pad_info.display_lines=LINES-TITLE_WIN_LINES-SHOW_WIN_LINES-COMMAND_WIN_LINES-2; + show_pad_info.display_cols=COLS; + } + } + clearok(title_win, 1); + clearok(show_win, 1); + clearok(command_win, 1); + clearok(mt_win1, 1); + clearok(mt_win2, 1); + wrefresh(mt_win1); + wrefresh(mt_win2); + refresh_show_pad(); + refresh_show_win(); + refresh_title_win (); + refresh_command_win (); +} -- cgit v1.2.3