/* getroot.c - Get root device */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2006,2007 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 <http://www.gnu.org/licenses/>.
*/
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <dirent.h>
#include <grub/util/misc.h>
#include <grub/util/biosdisk.h>
static void
strip_extra_slashes (char *dir)
{
char *p = dir;
while ((p = strchr (p, '/')) != 0)
{
if (p[1] == '/')
{
memmove (p, p + 1, strlen (p));
continue;
}
else if (p[1] == '\0')
{
p[0] = '\0';
break;
}
p++;
}
}
static char *
xgetcwd (void)
{
size_t size = 10;
char *path;
path = xmalloc (size);
while (! getcwd (path, size))
{
size <<= 1;
path = xrealloc (path, size);
}
return path;
}
char *
grub_get_prefix (const char *dir)
{
char *saved_cwd;
char *abs_dir, *prev_dir;
char *prefix;
struct stat st, prev_st;
/* Save the current directory. */
saved_cwd = xgetcwd ();
if (chdir (dir) < 0)
grub_util_error ("Cannot change directory to `%s'", dir);
abs_dir = xgetcwd ();
strip_extra_slashes (abs_dir);
prev_dir = xstrdup (abs_dir);
if (stat (".", &prev_st) < 0)
grub_util_error ("Cannot stat `%s'", dir);
if (! S_ISDIR (prev_st.st_mode))
grub_util_error ("`%s' is not a directory", dir);
while (1)
{
if (chdir ("..") < 0)
grub_util_error ("Cannot change directory to the parent");
if (stat (".", &st) < 0)
grub_util_error ("Cannot stat current directory");
if (! S_ISDIR (st.st_mode))
grub_util_error ("Current directory is not a directory???");
if (prev_st.st_dev != st.st_dev || prev_st.st_ino == st.st_ino)
break;
free (prev_dir);
prev_dir = xgetcwd ();
prev_st = st;
}
strip_extra_slashes (prev_dir);
prefix = xmalloc (strlen (abs_dir) - strlen (prev_dir) + 2);
prefix[0] = '/';
strcpy (prefix + 1, abs_dir + strlen (prev_dir));
strip_extra_slashes (prefix);
if (chdir (saved_cwd) < 0)
grub_util_error ("Cannot change directory to `%s'", dir);
free (saved_cwd);
free (abs_dir);
free (prev_dir);
grub_util_info ("prefix = %s", prefix);
return prefix;
}
static char *
find_root_device (const char *dir, dev_t dev)
{
DIR *dp;
char *saved_cwd;
struct dirent *ent;
dp = opendir (dir);
if (! dp)
return 0;
saved_cwd = xgetcwd ();
grub_util_info ("changing current directory to %s", dir);
if (chdir (dir) < 0)
{
free (saved_cwd);
closedir (dp);
return 0;
}
while ((ent = readdir (dp)) != 0)
{
struct stat st;
if (strcmp (ent->d_name, ".") == 0 || strcmp (ent->d_name, "..") == 0)
continue;
if (lstat (ent->d_name, &st) < 0)
/* Ignore any error. */
continue;
if (S_ISLNK (st.st_mode))
/* Don't follow symbolic links. */
continue;
if (S_ISDIR (st.st_mode) && ent->d_name[0] != '.')
{
/* Find it recursively, but avoid dotdirs (like ".static") since they
could contain duplicates, which would later break the
pathname-based check */
char *res;
res = find_root_device (ent->d_name, dev);
if (res)
{
if (chdir (saved_cwd) < 0)
grub_util_error ("Cannot restore the original directory");
free (saved_cwd);
closedir (dp);
return res;
}
}
if (S_ISBLK (st.st_mode) && st.st_rdev == dev)
{
/* Found! */
char *res;
char *cwd;
cwd = xgetcwd ();
res = xmalloc (strlen (cwd) + strlen (ent->d_name) + 2);
sprintf (res, "%s/%s", cwd, ent->d_name);
strip_extra_slashes (res);
free (cwd);
/* /dev/root is not a real block device keep looking, takes care
of situation where root filesystem is on the same partition as
grub files */
if (strcmp(res, "/dev/root") == 0)
continue;
if (chdir (saved_cwd) < 0)
grub_util_error ("Cannot restore the original directory");
free (saved_cwd);
closedir (dp);
return res;
}
}
if (chdir (saved_cwd) < 0)
grub_util_error ("Cannot restore the original directory");
free (saved_cwd);
closedir (dp);
return 0;
}
char *
grub_guess_root_device (const char *dir)
{
struct stat st;
char *os_dev;
if (stat (dir, &st) < 0)
grub_util_error ("Cannot stat `%s'", dir);
#ifdef __linux__
/* We first try to find the device in the /dev/mapper directory. If
we don't do this, we get useless device names like /dev/dm-0 for
LVM. */
os_dev = find_root_device ("/dev/mapper", st.st_dev);
if (!os_dev)
#endif
{
/* This might be truly slow, but is there any better way? */
os_dev = find_root_device ("/dev", st.st_dev);
}
return os_dev;
}
char *
grub_util_get_grub_dev (const char *os_dev)
{
/* Check for LVM. */
if (!strncmp (os_dev, "/dev/mapper/", 12))
{
char *grub_dev = xmalloc (strlen (os_dev) - 12 + 1);
strcpy (grub_dev, os_dev+12);
return grub_dev;
}
/* Check for RAID. */
if (!strncmp (os_dev, "/dev/md", 7))
{
const char *p;
char *grub_dev = xmalloc (20);
if (os_dev[7] == '_' && os_dev[8] == 'd')
{
/* This a partitionable RAID device of the form /dev/md_dNNpMM. */
int i;
grub_dev[0] = 'm';
grub_dev[1] = 'd';
i = 2;
p = os_dev + 9;
while (*p >= '0' && *p <= '9')
{
grub_dev[i] = *p;
i++;
p++;
}
if (*p == '\0')
grub_dev[i] = '\0';
else if (*p == 'p')
{
p++;
grub_dev[i] = ',';
i++;
while (*p >= '0' && *p <= '9')
{
grub_dev[i] = *p;
i++;
p++;
}
grub_dev[i] = '\0';
}
else
grub_util_error ("Unknown kind of RAID device `%s'", os_dev);
}
else if (os_dev[7] >= '0' && os_dev[7] <= '9')
{
p = os_dev + 5;
memcpy (grub_dev, p, 7);
grub_dev[7] = '\0';
}
else
grub_util_error ("Unknown kind of RAID device `%s'", os_dev);
return grub_dev;
}
/* If it's not RAID or LVM, it should be a biosdisk. */
return grub_util_biosdisk_get_grub_dev (os_dev);
}