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grub/grub-core/kern/emu/getroot.c

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/* getroot.c - Get root device */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2006,2007,2008,2009,2010 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 <config.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <dirent.h>
#include <errno.h>
#include <error.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <grub/util/misc.h>
#ifdef __GNU__
#include <hurd.h>
#include <hurd/lookup.h>
#include <hurd/fs.h>
#include <sys/mman.h>
#endif
#ifdef __linux__
# include <sys/types.h>
# include <sys/wait.h>
#endif
#if defined(HAVE_LIBZFS) && defined(HAVE_LIBNVPAIR)
# include <grub/util/libzfs.h>
# include <grub/util/libnvpair.h>
#endif
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/emu/misc.h>
#include <grub/emu/hostdisk.h>
#include <grub/emu/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 __linux__
/* Statting something on a btrfs filesystem always returns a virtual device
major/minor pair rather than the real underlying device, because btrfs
can span multiple underlying devices (and even if it's currently only
using a single device it can be dynamically extended onto another). We
can't deal with the multiple-device case yet, but in the meantime, we can
at least cope with the single-device case by scanning
/proc/self/mountinfo. */
static char *
find_root_device_from_mountinfo (const char *dir)
{
FILE *fp;
char *buf = NULL;
size_t len = 0;
char *ret = NULL;
fp = fopen ("/proc/self/mountinfo", "r");
if (! fp)
return NULL; /* fall through to other methods */
while (getline (&buf, &len, fp) > 0)
{
int mnt_id, parent_mnt_id;
unsigned int major, minor;
char enc_root[PATH_MAX], enc_path[PATH_MAX];
int count;
size_t enc_path_len;
const char *sep;
char fstype[PATH_MAX], device[PATH_MAX];
struct stat st;
if (sscanf (buf, "%d %d %u:%u %s %s%n",
&mnt_id, &parent_mnt_id, &major, &minor, enc_root, enc_path,
&count) < 6)
continue;
if (strcmp (enc_root, "/") != 0)
continue; /* only a subtree is mounted */
enc_path_len = strlen (enc_path);
if (strncmp (dir, enc_path, enc_path_len) != 0 ||
(dir[enc_path_len] && dir[enc_path_len] != '/'))
continue;
/* This is a parent of the requested directory. /proc/self/mountinfo
is in mount order, so it must be the closest parent we've
encountered so far. If it's virtual, return its device node;
otherwise, carry on to try to find something closer. */
free (ret);
ret = NULL;
if (major != 0)
continue; /* not a virtual device */
sep = strstr (buf + count, " - ");
if (!sep)
continue;
sep += sizeof (" - ") - 1;
if (sscanf (sep, "%s %s", fstype, device) != 2)
continue;
if (stat (device, &st) < 0)
continue;
if (!S_ISBLK (st.st_mode))
continue; /* not a block device */
ret = strdup (device);
}
free (buf);
fclose (fp);
return ret;
}
#endif /* __linux__ */
#if defined(HAVE_LIBZFS) && defined(HAVE_LIBNVPAIR)
static char *
find_root_device_from_libzfs (const char *dir)
{
char *device;
char *poolname;
char *poolfs;
grub_find_zpool_from_dir (dir, &poolname, &poolfs);
if (! poolname)
return NULL;
{
zpool_handle_t *zpool;
libzfs_handle_t *libzfs;
nvlist_t *nvlist;
nvlist_t **nvlist_array;
unsigned int nvlist_count;
libzfs = grub_get_libzfs_handle ();
if (! libzfs)
return NULL;
zpool = zpool_open (libzfs, poolname);
nvlist = zpool_get_config (zpool, NULL);
if (nvlist_lookup_nvlist (nvlist, "vdev_tree", &nvlist) != 0)
error (1, errno, "nvlist_lookup_nvlist (\"vdev_tree\")");
if (nvlist_lookup_nvlist_array (nvlist, "children", &nvlist_array, &nvlist_count) != 0)
error (1, errno, "nvlist_lookup_nvlist_array (\"children\")");
do
{
assert (nvlist_count > 0);
} while (nvlist_lookup_nvlist_array (nvlist_array[0], "children",
&nvlist_array, &nvlist_count) == 0);
if (nvlist_lookup_string (nvlist_array[0], "path", &device) != 0)
error (1, errno, "nvlist_lookup_string (\"path\")");
zpool_close (zpool);
}
free (poolname);
if (poolfs)
free (poolfs);
return device;
}
#endif
#ifdef __MINGW32__
static char *
find_root_device (const char *dir __attribute__ ((unused)),
dev_t dev __attribute__ ((unused)))
{
return 0;
}
#elif ! defined(__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)) {
#ifdef __linux__
if (strcmp (dir, "mapper") == 0) {
/* Follow symbolic links under /dev/mapper/; the canonical name
may be something like /dev/dm-0, but the names under
/dev/mapper/ are more human-readable and so we prefer them if
we can get them. */
if (stat (ent->d_name, &st) < 0)
continue;
} else
#endif /* __linux__ */
/* Don't follow other 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 defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__APPLE__)
if (S_ISCHR (st.st_mode) && st.st_rdev == dev)
#else
if (S_ISBLK (st.st_mode) && st.st_rdev == dev)
#endif
{
#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;
#if defined(__NetBSD__)
/* Convert this block device to its character (raw) device. */
const char *template = "%s/r%s";
#else
/* Keep the device name as it is. */
const char *template = "%s/%s";
#endif
cwd = xgetcwd ();
res = xmalloc (strlen (cwd) + strlen (ent->d_name) + 3);
sprintf (res, template, 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 partition 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)
{
char *os_dev;
#ifdef __GNU__
file_t file;
mach_port_t *ports;
int *ints;
loff_t *offsets;
char *data;
error_t err;
mach_msg_type_number_t num_ports = 0, num_ints = 0, num_offsets = 0, data_len = 0;
size_t name_len;
file = file_name_lookup (dir, 0, 0);
if (file == MACH_PORT_NULL)
return 0;
err = file_get_storage_info (file,
&ports, &num_ports,
&ints, &num_ints,
&offsets, &num_offsets,
&data, &data_len);
if (num_ints < 1)
grub_util_error ("Storage info for `%s' does not include type", dir);
if (ints[0] != STORAGE_DEVICE)
grub_util_error ("Filesystem of `%s' is not stored on local disk", dir);
if (num_ints < 5)
grub_util_error ("Storage info for `%s' does not include name", dir);
name_len = ints[4];
if (name_len < data_len)
grub_util_error ("Bogus name length for storage info for `%s'", dir);
if (data[name_len - 1] != '\0')
grub_util_error ("Storage name for `%s' not NUL-terminated", dir);
os_dev = xmalloc (strlen ("/dev/") + data_len);
memcpy (os_dev, "/dev/", strlen ("/dev/"));
memcpy (os_dev + strlen ("/dev/"), data, data_len);
if (ports && num_ports > 0)
{
mach_msg_type_number_t i;
for (i = 0; i < num_ports; i++)
{
mach_port_t port = ports[i];
if (port != MACH_PORT_NULL)
mach_port_deallocate (mach_task_self(), port);
}
munmap ((caddr_t) ports, num_ports * sizeof (*ports));
}
if (ints && num_ints > 0)
munmap ((caddr_t) ints, num_ints * sizeof (*ints));
if (offsets && num_offsets > 0)
munmap ((caddr_t) offsets, num_offsets * sizeof (*offsets));
if (data && data_len > 0)
munmap (data, data_len);
mach_port_deallocate (mach_task_self (), file);
#else /* !__GNU__ */
struct stat st;
#ifdef __linux__
os_dev = find_root_device_from_mountinfo (dir);
if (os_dev)
return os_dev;
#endif /* __linux__ */
#if defined(HAVE_LIBZFS) && defined(HAVE_LIBNVPAIR)
os_dev = find_root_device_from_libzfs (dir);
if (os_dev)
return os_dev;
#endif
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
#endif /* !__GNU__ */
return os_dev;
}
static int
grub_util_is_dmraid (const char *os_dev)
{
if (! strncmp (os_dev, "/dev/mapper/nvidia_", 19))
return 1;
else if (! strncmp (os_dev, "/dev/mapper/isw_", 16))
return 1;
else if (! strncmp (os_dev, "/dev/mapper/hpt37x_", 19))
return 1;
else if (! strncmp (os_dev, "/dev/mapper/hpt45x_", 19))
return 1;
else if (! strncmp (os_dev, "/dev/mapper/via_", 16))
return 1;
else if (! strncmp (os_dev, "/dev/mapper/lsi_", 16))
return 1;
else if (! strncmp (os_dev, "/dev/mapper/pdc_", 16))
return 1;
else if (! strncmp (os_dev, "/dev/mapper/jmicron_", 20))
return 1;
else if (! strncmp (os_dev, "/dev/mapper/asr_", 16))
return 1;
else if (! strncmp (os_dev, "/dev/mapper/sil_", 16))
return 1;
return 0;
}
int
grub_util_get_dev_abstraction (const char *os_dev __attribute__((unused)))
{
#ifdef __linux__
/* User explicitly claims that this drive is visible by BIOS. */
if (grub_util_biosdisk_is_present (os_dev))
return GRUB_DEV_ABSTRACTION_NONE;
/* Check for LVM. */
if (!strncmp (os_dev, "/dev/mapper/", 12)
&& ! grub_util_is_dmraid (os_dev)
&& strncmp (os_dev, "/dev/mapper/mpath", 17) != 0)
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;
}
#ifdef __linux__
static char *
get_mdadm_name (const char *os_dev)
{
int mdadm_pipe[2];
pid_t mdadm_pid;
char *name = NULL;
if (pipe (mdadm_pipe) < 0)
{
grub_util_warn ("Unable to create pipe for mdadm: %s", strerror (errno));
return NULL;
}
mdadm_pid = fork ();
if (mdadm_pid < 0)
grub_util_warn ("Unable to fork mdadm: %s", strerror (errno));
else if (mdadm_pid == 0)
{
/* Child. */
char *argv[5];
close (mdadm_pipe[0]);
dup2 (mdadm_pipe[1], STDOUT_FILENO);
close (mdadm_pipe[1]);
/* execvp has inconvenient types, hence the casts. None of these
strings will actually be modified. */
argv[0] = (char *) "mdadm";
argv[1] = (char *) "--detail";
argv[2] = (char *) "--export";
argv[3] = (char *) os_dev;
argv[4] = NULL;
execvp ("mdadm", argv);
exit (127);
}
else
{
/* Parent. Read mdadm's output. */
FILE *mdadm;
char *buf = NULL;
size_t len = 0;
close (mdadm_pipe[1]);
mdadm = fdopen (mdadm_pipe[0], "r");
if (! mdadm)
{
grub_util_warn ("Unable to open stream from mdadm: %s",
strerror (errno));
goto out;
}
while (getline (&buf, &len, mdadm) > 0)
{
if (strncmp (buf, "MD_NAME=", sizeof ("MD_NAME=") - 1) == 0)
{
char *name_start, *colon;
size_t name_len;
free (name);
name_start = buf + sizeof ("MD_NAME=") - 1;
/* Strip off the homehost if present. */
colon = strchr (name_start, ':');
name = strdup (colon ? colon + 1 : name_start);
name_len = strlen (name);
if (name[name_len - 1] == '\n')
name[name_len - 1] = '\0';
}
}
out:
close (mdadm_pipe[0]);
waitpid (mdadm_pid, NULL, 0);
}
return name;
}
#endif /* __linux__ */
char *
grub_util_get_grub_dev (const char *os_dev)
{
char *grub_dev = NULL;
switch (grub_util_get_dev_abstraction (os_dev))
{
case GRUB_DEV_ABSTRACTION_LVM:
{
unsigned short i, len;
grub_size_t offset = sizeof ("/dev/mapper/") - 1;
len = strlen (os_dev) - offset + 1;
grub_dev = xmalloc (len);
for (i = 0; i < len; i++, offset++)
{
grub_dev[i] = os_dev[offset];
if (os_dev[offset] == '-' && os_dev[offset + 1] == '-')
offset++;
}
}
break;
case GRUB_DEV_ABSTRACTION_RAID:
if (os_dev[7] == '_' && os_dev[8] == 'd')
{
/* This a partitionable RAID device of the form /dev/md_dNNpMM. */
char *p, *q;
p = strdup (os_dev + sizeof ("/dev/md_d") - 1);
q = strchr (p, 'p');
if (q)
*q = ',';
grub_dev = xasprintf ("md%s", p);
free (p);
}
else if (os_dev[7] == '/' && os_dev[8] == 'd')
{
/* This a partitionable RAID device of the form /dev/md/dNNpMM. */
char *p, *q;
p = strdup (os_dev + sizeof ("/dev/md/d") - 1);
q = strchr (p, 'p');
if (q)
*q = ',';
grub_dev = xasprintf ("md%s", p);
free (p);
}
else if (os_dev[7] >= '0' && os_dev[7] <= '9')
{
char *p , *q;
p = strdup (os_dev + sizeof ("/dev/md") - 1);
q = strchr (p, 'p');
if (q)
*q = ',';
grub_dev = xasprintf ("md%s", p);
free (p);
}
else if (os_dev[7] == '/' && os_dev[8] >= '0' && os_dev[8] <= '9')
{
char *p , *q;
p = strdup (os_dev + sizeof ("/dev/md/") - 1);
q = strchr (p, 'p');
if (q)
*q = ',';
grub_dev = xasprintf ("md%s", p);
free (p);
}
else if (os_dev[7] == '/')
{
/* mdraid 1.x with a free name. */
char *p , *q;
p = strdup (os_dev + sizeof ("/dev/md/") - 1);
q = strchr (p, 'p');
if (q)
*q = ',';
grub_dev = xasprintf ("md/%s", p);
free (p);
}
else
grub_util_error ("unknown kind of RAID device `%s'", os_dev);
#ifdef __linux__
{
char *mdadm_name = get_mdadm_name (os_dev);
if (mdadm_name)
{
free (grub_dev);
grub_dev = xasprintf ("md/%s", mdadm_name);
free (mdadm_name);
}
}
#endif /* __linux__ */
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;
}
const char *
grub_util_check_char_device (const char *blk_dev)
{
struct stat st;
if (stat (blk_dev, &st) < 0)
grub_util_error ("cannot stat `%s'", blk_dev);
if (S_ISCHR (st.st_mode))
return (blk_dev);
else
return 0;
}
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