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Diffstat (limited to '')
| -rw-r--r-- | mysys/my_symlink2.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/mysys/my_symlink2.c b/mysys/my_symlink2.c new file mode 100644 index 00000000..0b580ecd --- /dev/null +++ b/mysys/my_symlink2.c @@ -0,0 +1,191 @@ +/* Copyright (c) 2000, 2001, 2003, 2005-2007 MySQL AB + Use is subject to license terms + + 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; version 2 of the License. + + 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */ + +/* + Advanced symlink handling. + This is used in MyISAM to let users symlinks tables to different disk. + The main idea with these functions is to automatically create, delete and + rename files and symlinks like they would be one unit. +*/ + +#include "mysys_priv.h" +#include "mysys_err.h" +#include <m_string.h> + +File my_create_with_symlink(const char *linkname, const char *filename, + int createflags, int access_flags, myf MyFlags) +{ + File file; + int tmp_errno; + /* Test if we should create a link */ + int create_link; + char abs_linkname[FN_REFLEN]; + DBUG_ENTER("my_create_with_symlink"); + DBUG_PRINT("enter", ("linkname: %s filename: %s", + linkname ? linkname : "(NULL)", + filename ? filename : "(NULL)")); + + if (my_disable_symlinks) + { + DBUG_PRINT("info", ("Symlinks disabled")); + /* Create only the file, not the link and file */ + create_link= 0; + if (linkname) + filename= linkname; + } + else + { + if (linkname) + my_realpath(abs_linkname, linkname, MYF(0)); + create_link= (linkname && strcmp(abs_linkname,filename)); + } + + if (!(MyFlags & MY_DELETE_OLD)) + { + if (!access(filename,F_OK)) + { + my_errno= errno= EEXIST; + my_error(EE_CANTCREATEFILE, MYF(0), filename, EEXIST); + DBUG_RETURN(-1); + } + if (create_link && !access(linkname,F_OK)) + { + my_errno= errno= EEXIST; + my_error(EE_CANTCREATEFILE, MYF(0), linkname, EEXIST); + DBUG_RETURN(-1); + } + } + + if ((file=my_create(filename, createflags, access_flags, MyFlags)) >= 0) + { + if (create_link) + { + /* Delete old link/file */ + if (MyFlags & MY_DELETE_OLD) + my_delete(linkname, MYF(0)); + /* Create link */ + if (my_symlink(filename, linkname, MyFlags)) + { + /* Fail, remove everything we have done */ + tmp_errno=my_errno; + my_close(file,MYF(0)); + my_delete(filename, MYF(0)); + file= -1; + my_errno=tmp_errno; + } + } + } + DBUG_RETURN(file); +} + +/* + If the file is a normal file, just rename it. + If the file is a symlink: + - Create a new file with the name 'to' that points at + symlink_dir/basename(to) + - Rename the symlinked file to symlink_dir/basename(to) + - Delete 'from' + If something goes wrong, restore everything. +*/ + +int my_rename_with_symlink(const char *from, const char *to, myf MyFlags) +{ +#ifndef HAVE_READLINK + return my_rename(from, to, MyFlags); +#else + char link_name[FN_REFLEN], tmp_name[FN_REFLEN]; + int was_symlink= (!my_disable_symlinks && + !my_readlink(link_name, from, MYF(0))); + int result=0; + int name_is_different; + DBUG_ENTER("my_rename_with_symlink"); + + if (!was_symlink) + DBUG_RETURN(my_rename(from, to, MyFlags)); + + /* Change filename that symlink pointed to */ + strmov(tmp_name, to); + fn_same(tmp_name,link_name,1); /* Copy dir */ + name_is_different= strcmp(link_name, tmp_name); + if (name_is_different && !access(tmp_name, F_OK)) + { + my_errno= EEXIST; + if (MyFlags & MY_WME) + my_error(EE_CANTCREATEFILE, MYF(0), tmp_name, EEXIST); + DBUG_RETURN(1); + } + + /* Create new symlink */ + if (my_symlink(tmp_name, to, MyFlags)) + DBUG_RETURN(1); + + /* + Rename symlinked file if the base name didn't change. + This can happen if you use this function where 'from' and 'to' has + the same basename and different directories. + */ + + if (name_is_different && my_rename(link_name, tmp_name, MyFlags)) + { + int save_errno=my_errno; + my_delete(to, MyFlags); /* Remove created symlink */ + my_errno=save_errno; + DBUG_RETURN(1); + } + + /* Remove original symlink */ + if (my_delete(from, MyFlags)) + { + int save_errno=my_errno; + /* Remove created link */ + my_delete(to, MyFlags); + /* Rename file back */ + if (strcmp(link_name, tmp_name)) + (void) my_rename(tmp_name, link_name, MyFlags); + my_errno=save_errno; + result= 1; + } + DBUG_RETURN(result); +#endif /* HAVE_READLINK */ +} + +/** delete a - possibly symlinked - table file + + This is used to delete a file that is part of a table (e.g. MYI or MYD + file of MyISAM) when dropping a table. A file might be a symlink - + if the table was created with DATA DIRECTORY or INDEX DIRECTORY - + in this case both the symlink and the symlinked file are deleted, + but only if the symlinked file is not in the datadir. +*/ + +int my_handler_delete_with_symlink(const char *filename, myf sync_dir) +{ + char real[FN_REFLEN]; + int res= 0; + DBUG_ENTER("my_handler_delete_with_symlink"); + + if (my_is_symlink(filename)) + { + /* + Delete the symlinked file only if the symlink is not + pointing into datadir. + */ + if (!(my_realpath(real, filename, MYF(0)) || + mysys_test_invalid_symlink(real))) + res= my_delete(real, MYF(MY_NOSYMLINKS | sync_dir)); + } + DBUG_RETURN(my_delete(filename, sync_dir) || res); +} |