grub/grub-core/fs/archelp.c
Vladimir Serbinenko d3b464a7c0 archelp: Never pass NULL as mtime.
Moves complexity from fs code (NULL check) to common code (passing non-NULL).
2015-07-27 13:19:02 +02:00

301 lines
6.4 KiB
C

/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2007,2008,2009,2013 Free Software Foundation, Inc.
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include <grub/archelp.h>
#include <grub/err.h>
#include <grub/fs.h>
#include <grub/disk.h>
#include <grub/dl.h>
GRUB_MOD_LICENSE ("GPLv3+");
static inline void
canonicalize (char *name)
{
char *iptr, *optr;
for (iptr = name, optr = name; *iptr; )
{
while (*iptr == '/')
iptr++;
if (iptr[0] == '.' && (iptr[1] == '/' || iptr[1] == 0))
{
iptr++;
continue;
}
if (iptr[0] == '.' && iptr[1] == '.' && (iptr[2] == '/' || iptr[2] == 0))
{
iptr += 2;
if (optr == name)
continue;
for (optr -= 2; optr >= name && *optr != '/'; optr--);
optr++;
continue;
}
while (*iptr && *iptr != '/')
*optr++ = *iptr++;
if (*iptr)
*optr++ = *iptr++;
}
*optr = 0;
}
static grub_err_t
handle_symlink (struct grub_archelp_data *data,
struct grub_archelp_ops *arcops,
const char *fn, char **name,
grub_uint32_t mode, int *restart)
{
grub_size_t flen;
char *target;
char *ptr;
char *lastslash;
grub_size_t prefixlen;
char *rest;
char *linktarget;
grub_size_t linktarget_len;
*restart = 0;
if ((mode & GRUB_ARCHELP_ATTR_TYPE) != GRUB_ARCHELP_ATTR_LNK
|| !arcops->get_link_target)
return GRUB_ERR_NONE;
flen = grub_strlen (fn);
if (grub_memcmp (*name, fn, flen) != 0
|| ((*name)[flen] != 0 && (*name)[flen] != '/'))
return GRUB_ERR_NONE;
rest = *name + flen;
lastslash = rest;
if (*rest)
rest++;
while (lastslash >= *name && *lastslash != '/')
lastslash--;
if (lastslash >= *name)
prefixlen = lastslash - *name;
else
prefixlen = 0;
if (prefixlen)
prefixlen++;
linktarget = arcops->get_link_target (data);
if (!linktarget)
return grub_errno;
if (linktarget[0] == '\0')
return GRUB_ERR_NONE;
linktarget_len = grub_strlen (linktarget);
target = grub_malloc (linktarget_len + grub_strlen (*name) + 2);
if (!target)
return grub_errno;
grub_strcpy (target + prefixlen, linktarget);
grub_free (linktarget);
if (target[prefixlen] == '/')
{
ptr = grub_stpcpy (target, target + prefixlen);
ptr = grub_stpcpy (ptr, rest);
*ptr = 0;
grub_dprintf ("archelp", "symlink redirected %s to %s\n",
*name, target);
grub_free (*name);
canonicalize (target);
*name = target;
*restart = 1;
return GRUB_ERR_NONE;
}
if (prefixlen)
{
grub_memcpy (target, *name, prefixlen);
target[prefixlen-1] = '/';
}
grub_strcpy (target + prefixlen + linktarget_len, rest);
grub_dprintf ("archelp", "symlink redirected %s to %s\n",
*name, target);
grub_free (*name);
canonicalize (target);
*name = target;
*restart = 1;
return GRUB_ERR_NONE;
}
grub_err_t
grub_archelp_dir (struct grub_archelp_data *data,
struct grub_archelp_ops *arcops,
const char *path_in,
grub_fs_dir_hook_t hook, void *hook_data)
{
char *prev, *name, *path, *ptr;
grub_size_t len;
int symlinknest = 0;
path = grub_strdup (path_in + 1);
if (!path)
return grub_errno;
canonicalize (path);
for (ptr = path + grub_strlen (path) - 1; ptr >= path && *ptr == '/'; ptr--)
*ptr = 0;
prev = 0;
len = grub_strlen (path);
while (1)
{
grub_int32_t mtime;
grub_uint32_t mode;
grub_err_t err;
if (arcops->find_file (data, &name, &mtime, &mode))
goto fail;
if (mode == GRUB_ARCHELP_ATTR_END)
break;
canonicalize (name);
if (grub_memcmp (path, name, len) == 0
&& (name[len] == 0 || name[len] == '/' || len == 0))
{
char *p, *n;
n = name + len;
while (*n == '/')
n++;
p = grub_strchr (n, '/');
if (p)
*p = 0;
if (((!prev) || (grub_strcmp (prev, name) != 0)) && *n != 0)
{
struct grub_dirhook_info info;
grub_memset (&info, 0, sizeof (info));
info.dir = (p != NULL) || ((mode & GRUB_ARCHELP_ATTR_TYPE)
== GRUB_ARCHELP_ATTR_DIR);
if (!(mode & GRUB_ARCHELP_ATTR_NOTIME))
{
info.mtime = mtime;
info.mtimeset = 1;
}
if (hook (n, &info, hook_data))
{
grub_free (name);
goto fail;
}
grub_free (prev);
prev = name;
}
else
{
int restart = 0;
err = handle_symlink (data, arcops, name,
&path, mode, &restart);
grub_free (name);
if (err)
goto fail;
if (restart)
{
len = grub_strlen (path);
if (++symlinknest == 8)
{
grub_error (GRUB_ERR_SYMLINK_LOOP,
N_("too deep nesting of symlinks"));
goto fail;
}
arcops->rewind (data);
}
}
}
else
grub_free (name);
}
fail:
grub_free (path);
grub_free (prev);
return grub_errno;
}
grub_err_t
grub_archelp_open (struct grub_archelp_data *data,
struct grub_archelp_ops *arcops,
const char *name_in)
{
char *fn;
char *name = grub_strdup (name_in + 1);
int symlinknest = 0;
if (!name)
return grub_errno;
canonicalize (name);
while (1)
{
grub_uint32_t mode;
grub_int32_t mtime;
int restart;
if (arcops->find_file (data, &fn, &mtime, &mode))
goto fail;
if (mode == GRUB_ARCHELP_ATTR_END)
{
grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("file `%s' not found"), name_in);
break;
}
canonicalize (fn);
if (handle_symlink (data, arcops, fn, &name, mode, &restart))
{
grub_free (fn);
goto fail;
}
if (restart)
{
arcops->rewind (data);
if (++symlinknest == 8)
{
grub_error (GRUB_ERR_SYMLINK_LOOP,
N_("too deep nesting of symlinks"));
goto fail;
}
goto no_match;
}
if (grub_strcmp (name, fn) != 0)
goto no_match;
grub_free (fn);
grub_free (name);
return GRUB_ERR_NONE;
no_match:
grub_free (fn);
}
fail:
grub_free (name);
return grub_errno;
}