grub/util/getroot.c
robertmh 8415f2617c 2008-08-23 Robert Millan <rmh@aybabtu.com>
* util/getroot.c (find_root_device): Skip anything that starts with
        a dot, not just directories.  This avoids things like /dev/.tmp.md0.
2008-08-23 12:19:43 +00:00

488 lines
11 KiB
C

/* getroot.c - Get root device */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2006,2007,2008 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 <http://www.gnu.org/licenses/>.
*/
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <dirent.h>
#ifdef __CYGWIN__
# include <sys/fcntl.h>
# include <sys/cygwin.h>
# include <limits.h>
# define DEV_CYGDRIVE_MAJOR 98
#endif
#include <grub/util/misc.h>
#include <grub/util/biosdisk.h>
#include <grub/util/getroot.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')
{
if (p > dir)
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;
}
#ifdef __CYGWIN__
/* Convert POSIX path to Win32 path,
remove drive letter, replace backslashes. */
static char *
get_win32_path (const char *path)
{
char winpath[PATH_MAX];
cygwin_conv_to_full_win32_path (path, winpath);
int len = strlen (winpath);
if (len > 2 && winpath[1] == ':')
{
len -= 2;
memmove (winpath, winpath + 2, len + 1);
}
int i;
for (i = 0; i < len; i++)
if (winpath[i] == '\\')
winpath[i] = '/';
return xstrdup (winpath);
}
#endif
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);
#ifdef __CYGWIN__
if (st.st_dev != (DEV_CYGDRIVE_MAJOR << 16))
{
/* Reached some mount point not below /cygdrive.
GRUB does not know Cygwin's emulated mounts,
convert to Win32 path. */
grub_util_info ("Cygwin prefix = %s", prefix);
char * wprefix = get_win32_path (prefix);
free (prefix);
prefix = wprefix;
}
#endif
free (saved_cwd);
free (abs_dir);
free (prev_dir);
grub_util_info ("prefix = %s", prefix);
return prefix;
}
#ifndef __CYGWIN__
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;
/* Avoid:
- dotfiles (like "/dev/.tmp.md0") since they could be duplicates.
- dotdirs (like "/dev/.static") since they could contain duplicates. */
if (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))
{
/* Find it recursively. */
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)
{
#ifdef __linux__
/* Skip device names like /dev/dm-0, which are short-hand aliases
to more descriptive device names, e.g. those under /dev/mapper */
if (ent->d_name[0] == 'd' &&
ent->d_name[1] == 'm' &&
ent->d_name[2] == '-' &&
ent->d_name[3] >= '0' &&
ent->d_name[3] <= '9')
continue;
#endif
/* 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;
}
#else /* __CYGWIN__ */
/* Read drive/partition serial number from mbr/boot sector,
return 0 on read error, ~0 on unknown serial. */
static unsigned
get_bootsec_serial (const char *os_dev, int mbr)
{
/* Read boot sector. */
int fd = open (os_dev, O_RDONLY);
if (fd < 0)
return 0;
unsigned char buf[0x200];
int n = read (fd, buf, sizeof (buf));
close (fd);
if (n != sizeof(buf))
return 0;
/* Check signature. */
if (!(buf[0x1fe] == 0x55 && buf[0x1ff] == 0xaa))
return ~0;
/* Serial number offset depends on boot sector type. */
if (mbr)
n = 0x1b8;
else if (memcmp (buf + 0x03, "NTFS", 4) == 0)
n = 0x048;
else if (memcmp (buf + 0x52, "FAT32", 5) == 0)
n = 0x043;
else if (memcmp (buf + 0x36, "FAT", 3) == 0)
n = 0x027;
else
return ~0;
unsigned serial = *(unsigned *)(buf + n);
if (serial == 0)
return ~0;
return serial;
}
static char *
find_cygwin_root_device (const char *path, dev_t dev)
{
/* No root device for /cygdrive. */
if (dev == (DEV_CYGDRIVE_MAJOR << 16))
return 0;
/* Convert to full POSIX and Win32 path. */
char fullpath[PATH_MAX], winpath[PATH_MAX];
cygwin_conv_to_full_posix_path (path, fullpath);
cygwin_conv_to_full_win32_path (fullpath, winpath);
/* If identical, this is no real filesystem path. */
if (strcmp (fullpath, winpath) == 0)
return 0;
/* Check for floppy drive letter. */
if (winpath[0] && winpath[1] == ':' && strchr ("AaBb", winpath[0]))
return xstrdup (strchr ("Aa", winpath[0]) ? "/dev/fd0" : "/dev/fd1");
/* Cygwin returns the partition serial number in stat.st_dev.
This is never identical to the device number of the emulated
/dev/sdXN device, so above find_root_device () does not work.
Search the partion with the same serial in boot sector instead. */
char devpath[sizeof ("/dev/sda15") + 13]; /* Size + Paranoia. */
int d;
for (d = 'a'; d <= 'z'; d++)
{
sprintf (devpath, "/dev/sd%c", d);
if (get_bootsec_serial (devpath, 1) == 0)
continue;
int p;
for (p = 1; p <= 15; p++)
{
sprintf (devpath, "/dev/sd%c%d", d, p);
unsigned ser = get_bootsec_serial (devpath, 0);
if (ser == 0)
break;
if (ser != (unsigned)~0 && dev == (dev_t)ser)
return xstrdup (devpath);
}
}
return 0;
}
#endif /* __CYGWIN__ */
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 __CYGWIN__
/* Cygwin specific function. */
os_dev = find_cygwin_root_device (dir, st.st_dev);
#else
/* This might be truly slow, but is there any better way? */
os_dev = find_root_device ("/dev", st.st_dev);
#endif
return os_dev;
}
int
grub_util_get_dev_abstraction (const char *os_dev)
{
#ifdef __linux__
/* Check for LVM. */
if (!strncmp (os_dev, "/dev/mapper/", 12))
return GRUB_DEV_ABSTRACTION_LVM;
/* Check for RAID. */
if (!strncmp (os_dev, "/dev/md", 7))
return GRUB_DEV_ABSTRACTION_RAID;
#endif
/* No abstraction found. */
return GRUB_DEV_ABSTRACTION_NONE;
}
char *
grub_util_get_grub_dev (const char *os_dev)
{
char *grub_dev;
switch (grub_util_get_dev_abstraction (os_dev))
{
case GRUB_DEV_ABSTRACTION_LVM:
grub_dev = xmalloc (strlen (os_dev) - 12 + 1);
strcpy (grub_dev, os_dev + 12);
break;
case GRUB_DEV_ABSTRACTION_RAID:
grub_dev = xmalloc (20);
if (os_dev[7] == '_' && os_dev[8] == 'd')
{
const char *p;
/* 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')
{
memcpy (grub_dev, os_dev + 5, 7);
grub_dev[7] = '\0';
}
else
grub_util_error ("Unknown kind of RAID device `%s'", os_dev);
break;
default: /* GRUB_DEV_ABSTRACTION_NONE */
grub_dev = grub_util_biosdisk_get_grub_dev (os_dev);
}
return grub_dev;
}
const char *
grub_util_check_block_device (const char *blk_dev)
{
struct stat st;
if (stat (blk_dev, &st) < 0)
grub_util_error ("Cannot stat `%s'", blk_dev);
if (S_ISBLK (st.st_mode))
return (blk_dev);
else
return 0;
}