/* 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
GRUB_MOD_LICENSE ("GPLv3+");
/* 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. Make
sure you use the NESTED_FUNC_ATTR macro for HOOK, this is required
because GCC has a nasty bug when using regparm=3. */
grub_err_t
grub_fshelp_find_file (const char *path, grub_fshelp_node_t rootnode,
grub_fshelp_node_t *foundnode,
int (*iterate_dir) (grub_fshelp_node_t dir,
int NESTED_FUNC_ATTR (*hook)
(const char *filename,
enum grub_fshelp_filetype filetype,
grub_fshelp_node_t node)),
char *(*read_symlink) (grub_fshelp_node_t node),
enum grub_fshelp_filetype expecttype)
{
grub_err_t err;
enum grub_fshelp_filetype foundtype = GRUB_FSHELP_DIR;
int symlinknest = 0;
auto grub_err_t NESTED_FUNC_ATTR find_file (const char *currpath,
grub_fshelp_node_t currroot,
grub_fshelp_node_t *currfound);
grub_err_t NESTED_FUNC_ATTR find_file (const char *currpath,
grub_fshelp_node_t currroot,
grub_fshelp_node_t *currfound)
{
char fpath[grub_strlen (currpath) + 1];
char *name = fpath;
char *next;
enum grub_fshelp_filetype type = GRUB_FSHELP_DIR;
grub_fshelp_node_t currnode = currroot;
grub_fshelp_node_t oldnode = currroot;
auto int NESTED_FUNC_ATTR iterate (const char *filename,
enum grub_fshelp_filetype filetype,
grub_fshelp_node_t node);
auto void free_node (grub_fshelp_node_t node);
void free_node (grub_fshelp_node_t node)
{
if (node != rootnode && node != currroot)
grub_free (node);
}
int NESTED_FUNC_ATTR iterate (const char *filename,
enum grub_fshelp_filetype filetype,
grub_fshelp_node_t node)
{
if (filetype == GRUB_FSHELP_UNKNOWN ||
(grub_strcmp (name, filename) &&
(! (filetype & GRUB_FSHELP_CASE_INSENSITIVE) ||
grub_strcasecmp (name, filename))))
{
grub_free (node);
return 0;
}
/* The node is found, stop iterating over the nodes. */
type = filetype & ~GRUB_FSHELP_CASE_INSENSITIVE;
oldnode = currnode;
currnode = node;
return 1;
}
grub_strncpy (fpath, currpath, grub_strlen (currpath) + 1);
/* Remove all leading slashes. */
while (*name == '/')
name++;
if (! *name)
{
*currfound = currnode;
return 0;
}
for (;;)
{
int found;
/* Extract the actual part from the pathname. */
next = grub_strchr (name, '/');
if (next)
{
/* Remove all leading slashes. */
while (*next == '/')
*(next++) = '\0';
}
/* At this point it is expected that the current node is a
directory, check if this is true. */
if (type != GRUB_FSHELP_DIR)
{
free_node (currnode);
return grub_error (GRUB_ERR_BAD_FILE_TYPE, "not a directory");
}
/* Iterate over the directory. */
found = iterate_dir (currnode, iterate);
if (! found)
{
if (grub_errno)
return grub_errno;
break;
}
/* Read in the symlink and follow it. */
if (type == GRUB_FSHELP_SYMLINK)
{
char *symlink;
/* Test if the symlink does not loop. */
if (++symlinknest == 8)
{
free_node (currnode);
free_node (oldnode);
return grub_error (GRUB_ERR_SYMLINK_LOOP,
"too deep nesting of symlinks");
}
symlink = read_symlink (currnode);
free_node (currnode);
if (!symlink)
{
free_node (oldnode);
return grub_errno;
}
/* The symlink is an absolute path, go back to the root inode. */
if (symlink[0] == '/')
{
free_node (oldnode);
oldnode = rootnode;
}
/* Lookup the node the symlink points to. */
find_file (symlink, oldnode, &currnode);
type = foundtype;
grub_free (symlink);
if (grub_errno)
{
free_node (oldnode);
return grub_errno;
}
}
free_node (oldnode);
/* Found the node! */
if (! next || *next == '\0')
{
*currfound = currnode;
foundtype = type;
return 0;
}
name = next;
}
return grub_error (GRUB_ERR_FILE_NOT_FOUND, "file `%s' not found", path);
}
if (!path || path[0] != '/')
{
grub_error (GRUB_ERR_BAD_FILENAME, "bad filename");
return grub_errno;
}
err = find_file (path, rootnode, foundnode);
if (err)
return err;
/* 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, "not a regular file");
else if (expecttype == GRUB_FSHELP_DIR && foundtype != expecttype)
return grub_error (GRUB_ERR_BAD_FILE_TYPE, "not a directory");
return 0;
}
/* 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. 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,
void NESTED_FUNC_ATTR (*read_hook) (grub_disk_addr_t sector,
unsigned offset,
unsigned length),
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 i, blockcnt;
int blocksize = 1 << (log2blocksize + GRUB_DISK_SECTOR_BITS);
/* 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;
grub_disk_read (disk, blknr, skipfirst,
blockend, buf);
disk->read_hook = 0;
if (grub_errno)
return -1;
}
else
grub_memset (buf, 0, blockend);
buf += blocksize - skipfirst;
}
return len;
}
unsigned int
grub_fshelp_log2blksize (unsigned int blksize, unsigned int *pow)
{
int mod;
*pow = 0;
while (blksize > 1)
{
mod = blksize - ((blksize >> 1) << 1);
blksize >>= 1;
/* Check if it really is a power of two. */
if (mod)
return grub_error (GRUB_ERR_BAD_NUMBER,
"the blocksize is not a power of two");
(*pow)++;
}
return GRUB_ERR_NONE;
}