From 6e7a315eb67cb6c113cf37e1d66c4f11a51a2b3e Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 18:29:51 +0200 Subject: Adding upstream version 2.06. Signed-off-by: Daniel Baumann --- grub-core/fs/fshelp.c | 441 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 441 insertions(+) create mode 100644 grub-core/fs/fshelp.c (limited to 'grub-core/fs/fshelp.c') diff --git a/grub-core/fs/fshelp.c b/grub-core/fs/fshelp.c new file mode 100644 index 0000000..a2d0d29 --- /dev/null +++ b/grub-core/fs/fshelp.c @@ -0,0 +1,441 @@ +/* fshelp.c -- Filesystem helper functions */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2004,2005,2006,2007,2008 Free Software Foundation, Inc. + * + * GRUB 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 3 of the License, or + * (at your option) any later version. + * + * GRUB 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 GRUB. If not, see . + */ + +#include +#include +#include +#include +#include +#include +#include + +GRUB_MOD_LICENSE ("GPLv3+"); + +typedef int (*iterate_dir_func) (grub_fshelp_node_t dir, + grub_fshelp_iterate_dir_hook_t hook, + void *data); +typedef grub_err_t (*lookup_file_func) (grub_fshelp_node_t dir, + const char *name, + grub_fshelp_node_t *foundnode, + enum grub_fshelp_filetype *foundtype); +typedef char *(*read_symlink_func) (grub_fshelp_node_t node); + +struct stack_element { + struct stack_element *parent; + grub_fshelp_node_t node; + enum grub_fshelp_filetype type; +}; + +/* Context for grub_fshelp_find_file. */ +struct grub_fshelp_find_file_ctx +{ + /* Inputs. */ + const char *path; + grub_fshelp_node_t rootnode; + + /* Global options. */ + int symlinknest; + + /* Current file being traversed and its parents. */ + struct stack_element *currnode; +}; + +/* Helper for find_file_iter. */ +static void +free_node (grub_fshelp_node_t node, struct grub_fshelp_find_file_ctx *ctx) +{ + if (node != ctx->rootnode) + grub_free (node); +} + +static void +pop_element (struct grub_fshelp_find_file_ctx *ctx) +{ + struct stack_element *el; + el = ctx->currnode; + ctx->currnode = el->parent; + free_node (el->node, ctx); + grub_free (el); +} + +static void +free_stack (struct grub_fshelp_find_file_ctx *ctx) +{ + while (ctx->currnode) + pop_element (ctx); +} + +static void +go_up_a_level (struct grub_fshelp_find_file_ctx *ctx) +{ + if (!ctx->currnode->parent) + return; + pop_element (ctx); +} + +static grub_err_t +push_node (struct grub_fshelp_find_file_ctx *ctx, grub_fshelp_node_t node, enum grub_fshelp_filetype filetype) +{ + struct stack_element *nst; + nst = grub_malloc (sizeof (*nst)); + if (!nst) + return grub_errno; + nst->node = node; + nst->type = filetype & ~GRUB_FSHELP_CASE_INSENSITIVE; + nst->parent = ctx->currnode; + ctx->currnode = nst; + return GRUB_ERR_NONE; +} + +static grub_err_t +go_to_root (struct grub_fshelp_find_file_ctx *ctx) +{ + free_stack (ctx); + return push_node (ctx, ctx->rootnode, GRUB_FSHELP_DIR); +} + +struct grub_fshelp_find_file_iter_ctx +{ + const char *name; + grub_fshelp_node_t *foundnode; + enum grub_fshelp_filetype *foundtype; +}; + +/* Helper for grub_fshelp_find_file. */ +static int +find_file_iter (const char *filename, enum grub_fshelp_filetype filetype, + grub_fshelp_node_t node, void *data) +{ + struct grub_fshelp_find_file_iter_ctx *ctx = data; + + if (filetype == GRUB_FSHELP_UNKNOWN || + ((filetype & GRUB_FSHELP_CASE_INSENSITIVE) + ? grub_strcasecmp (ctx->name, filename) + : grub_strcmp (ctx->name, filename))) + { + grub_free (node); + return 0; + } + + /* The node is found, stop iterating over the nodes. */ + *ctx->foundnode = node; + *ctx->foundtype = filetype; + return 1; +} + +static grub_err_t +directory_find_file (grub_fshelp_node_t node, const char *name, grub_fshelp_node_t *foundnode, + enum grub_fshelp_filetype *foundtype, iterate_dir_func iterate_dir) +{ + int found; + struct grub_fshelp_find_file_iter_ctx ctx = { + .foundnode = foundnode, + .foundtype = foundtype, + .name = name + }; + found = iterate_dir (node, find_file_iter, &ctx); + if (! found) + { + if (grub_errno) + return grub_errno; + } + return GRUB_ERR_NONE; +} + +static grub_err_t +find_file (char *currpath, + iterate_dir_func iterate_dir, lookup_file_func lookup_file, + read_symlink_func read_symlink, + struct grub_fshelp_find_file_ctx *ctx) +{ + char *name, *next; + grub_err_t err; + for (name = currpath; ; name = next) + { + char c; + grub_fshelp_node_t foundnode = NULL; + enum grub_fshelp_filetype foundtype = 0; + + /* Remove all leading slashes. */ + while (*name == '/') + name++; + + /* Found the node! */ + if (! *name) + return 0; + + /* Extract the actual part from the pathname. */ + for (next = name; *next && *next != '/'; next++); + + /* At this point it is expected that the current node is a + directory, check if this is true. */ + if (ctx->currnode->type != GRUB_FSHELP_DIR) + return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a directory")); + + /* Don't rely on fs providing actual . in the listing. */ + if (next - name == 1 && name[0] == '.') + continue; + + /* Don't rely on fs providing actual .. in the listing. */ + if (next - name == 2 && name[0] == '.' && name[1] == '.') + { + go_up_a_level (ctx); + continue; + } + + /* Iterate over the directory. */ + c = *next; + *next = '\0'; + if (lookup_file) + err = lookup_file (ctx->currnode->node, name, &foundnode, &foundtype); + else + err = directory_find_file (ctx->currnode->node, name, &foundnode, &foundtype, iterate_dir); + *next = c; + + if (err) + return err; + + if (!foundnode) + break; + + push_node (ctx, foundnode, foundtype); + + /* Read in the symlink and follow it. */ + if (ctx->currnode->type == GRUB_FSHELP_SYMLINK) + { + char *symlink; + + /* Test if the symlink does not loop. */ + if (++ctx->symlinknest == 8) + return grub_error (GRUB_ERR_SYMLINK_LOOP, + N_("too deep nesting of symlinks")); + + symlink = read_symlink (ctx->currnode->node); + + if (!symlink) + return grub_errno; + + /* The symlink is an absolute path, go back to the root inode. */ + if (symlink[0] == '/') + { + err = go_to_root (ctx); + if (err) + return err; + } + else + { + /* Get from symlink to containing directory. */ + go_up_a_level (ctx); + } + + + /* Lookup the node the symlink points to. */ + find_file (symlink, iterate_dir, lookup_file, read_symlink, ctx); + grub_free (symlink); + + if (grub_errno) + return grub_errno; + } + } + + return grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("file `%s' not found"), + ctx->path); +} + +static grub_err_t +grub_fshelp_find_file_real (const char *path, grub_fshelp_node_t rootnode, + grub_fshelp_node_t *foundnode, + iterate_dir_func iterate_dir, + lookup_file_func lookup_file, + read_symlink_func read_symlink, + enum grub_fshelp_filetype expecttype) +{ + struct grub_fshelp_find_file_ctx ctx = { + .path = path, + .rootnode = rootnode, + .symlinknest = 0, + .currnode = 0 + }; + grub_err_t err; + enum grub_fshelp_filetype foundtype; + char *duppath; + + if (!path || path[0] != '/') + { + return grub_error (GRUB_ERR_BAD_FILENAME, N_("invalid file name `%s'"), path); + } + + err = go_to_root (&ctx); + if (err) + return err; + + duppath = grub_strdup (path); + if (!duppath) + return grub_errno; + err = find_file (duppath, iterate_dir, lookup_file, read_symlink, &ctx); + grub_free (duppath); + if (err) + { + free_stack (&ctx); + return err; + } + + *foundnode = ctx.currnode->node; + foundtype = ctx.currnode->type; + /* Avoid the node being freed. */ + ctx.currnode->node = 0; + free_stack (&ctx); + + /* Check if the node that was found was of the expected type. */ + if (expecttype == GRUB_FSHELP_REG && foundtype != expecttype) + return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a regular file")); + else if (expecttype == GRUB_FSHELP_DIR && foundtype != expecttype) + return grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a directory")); + + return 0; +} + +/* Lookup the node PATH. The node ROOTNODE describes the root of the + directory tree. The node found is returned in FOUNDNODE, which is + either a ROOTNODE or a new malloc'ed node. ITERATE_DIR is used to + iterate over all directory entries in the current node. + READ_SYMLINK is used to read the symlink if a node is a symlink. + EXPECTTYPE is the type node that is expected by the called, an + error is generated if the node is not of the expected type. */ +grub_err_t +grub_fshelp_find_file (const char *path, grub_fshelp_node_t rootnode, + grub_fshelp_node_t *foundnode, + iterate_dir_func iterate_dir, + read_symlink_func read_symlink, + enum grub_fshelp_filetype expecttype) +{ + return grub_fshelp_find_file_real (path, rootnode, foundnode, + iterate_dir, NULL, + read_symlink, expecttype); + +} + +grub_err_t +grub_fshelp_find_file_lookup (const char *path, grub_fshelp_node_t rootnode, + grub_fshelp_node_t *foundnode, + lookup_file_func lookup_file, + read_symlink_func read_symlink, + enum grub_fshelp_filetype expecttype) +{ + return grub_fshelp_find_file_real (path, rootnode, foundnode, + NULL, lookup_file, + read_symlink, expecttype); + +} + +/* Read LEN bytes from the file NODE on disk DISK into the buffer BUF, + beginning with the block POS. READ_HOOK should be set before + reading a block from the file. READ_HOOK_DATA is passed through as + the DATA argument to READ_HOOK. GET_BLOCK is used to translate + file blocks to disk blocks. The file is FILESIZE bytes big and the + blocks have a size of LOG2BLOCKSIZE (in log2). */ +grub_ssize_t +grub_fshelp_read_file (grub_disk_t disk, grub_fshelp_node_t node, + grub_disk_read_hook_t read_hook, void *read_hook_data, + grub_off_t pos, grub_size_t len, char *buf, + grub_disk_addr_t (*get_block) (grub_fshelp_node_t node, + grub_disk_addr_t block), + grub_off_t filesize, int log2blocksize, + grub_disk_addr_t blocks_start) +{ + grub_disk_addr_t i, blockcnt; + int blocksize = 1 << (log2blocksize + GRUB_DISK_SECTOR_BITS); + + /* + * Catch blatantly invalid log2blocksize. We could be a lot stricter, but + * this is the most permissive we can be before we start to see integer + * overflow/underflow issues. + */ + if (log2blocksize + GRUB_DISK_SECTOR_BITS >= 31) + { + grub_error (GRUB_ERR_OUT_OF_RANGE, + N_("blocksize too large")); + return -1; + } + + if (pos > filesize) + { + grub_error (GRUB_ERR_OUT_OF_RANGE, + N_("attempt to read past the end of file")); + return -1; + } + + /* Adjust LEN so it we can't read past the end of the file. */ + if (pos + len > filesize) + len = filesize - pos; + + blockcnt = ((len + pos) + blocksize - 1) >> (log2blocksize + GRUB_DISK_SECTOR_BITS); + + for (i = pos >> (log2blocksize + GRUB_DISK_SECTOR_BITS); i < blockcnt; i++) + { + grub_disk_addr_t blknr; + int blockoff = pos & (blocksize - 1); + int blockend = blocksize; + + int skipfirst = 0; + + blknr = get_block (node, i); + if (grub_errno) + return -1; + + blknr = blknr << log2blocksize; + + /* Last block. */ + if (i == blockcnt - 1) + { + blockend = (len + pos) & (blocksize - 1); + + /* The last portion is exactly blocksize. */ + if (! blockend) + blockend = blocksize; + } + + /* First block. */ + if (i == (pos >> (log2blocksize + GRUB_DISK_SECTOR_BITS))) + { + skipfirst = blockoff; + blockend -= skipfirst; + } + + /* If the block number is 0 this block is not stored on disk but + is zero filled instead. */ + if (blknr) + { + disk->read_hook = read_hook; + disk->read_hook_data = read_hook_data; + + grub_disk_read (disk, blknr + blocks_start, skipfirst, + blockend, buf); + disk->read_hook = 0; + if (grub_errno) + return -1; + } + else + grub_memset (buf, 0, blockend); + + buf += blocksize - skipfirst; + } + + return len; +} -- cgit v1.2.3