grub/util/getroot_linux.c

/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1999,2000,2001,2002,2003,2006,2007,2008,2009,2010,2011,2012,2013  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-util.h>
#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>
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif

#include <grub/types.h>
#include <sys/ioctl.h>         /* ioctl */
#include <sys/mount.h>

#include <grub/util/misc.h>
#include <grub/util/lvm.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/emu/misc.h>
#include <grub/emu/hostdisk.h>
#include <grub/emu/getroot.h>

#include <sys/wait.h>


/* Defines taken from btrfs/ioctl.h.  */

struct btrfs_ioctl_dev_info_args
{
  grub_uint64_t devid;
  grub_uint8_t uuid[16];
  grub_uint64_t bytes_used;
  grub_uint64_t total_bytes;
  grub_uint64_t unused[379];
  grub_uint8_t path[1024];
};

struct btrfs_ioctl_fs_info_args
{
  grub_uint64_t max_id;
  grub_uint64_t num_devices;
  grub_uint8_t fsid[16];
  grub_uint64_t reserved[124];
};

#define BTRFS_IOC_DEV_INFO _IOWR(0x94, 30, \
                                 struct btrfs_ioctl_dev_info_args)
#define BTRFS_IOC_FS_INFO _IOR(0x94, 31, \
                               struct btrfs_ioctl_fs_info_args)

static int
grub_util_is_imsm (const char *os_dev);


#define ESCAPED_PATH_MAX (4 * PATH_MAX)
struct mountinfo_entry
{
  int id;
  int major, minor;
  char enc_root[ESCAPED_PATH_MAX + 1], enc_path[ESCAPED_PATH_MAX + 1];
  char fstype[ESCAPED_PATH_MAX + 1], device[ESCAPED_PATH_MAX + 1];
};

/* 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 void
unescape (char *str)
{
  char *optr;
  const char *iptr;
  for (iptr = optr = str; *iptr; optr++)
    {
      if (iptr[0] == '\\' && iptr[1] >= '0' && iptr[1] < '8'
	  && iptr[2] >= '0' && iptr[2] < '8'
	  && iptr[3] >= '0' && iptr[3] < '8')
	{
	  *optr = (((iptr[1] - '0') << 6) | ((iptr[2] - '0') << 3)
		   | (iptr[3] - '0'));
	  iptr += 4;
	}
      else
	*optr = *iptr++;
    }
  *optr = 0;
}

static char **
grub_find_root_devices_from_btrfs (const char *dir)
{
  int fd;
  struct btrfs_ioctl_fs_info_args fsi;
  int i, j = 0;
  char **ret;

  fd = open (dir, 0);
  if (!fd)
    return NULL;

  if (ioctl (fd, BTRFS_IOC_FS_INFO, &fsi) < 0)
    {
      close (fd);
      return NULL;
    }

  ret = xmalloc ((fsi.num_devices + 1) * sizeof (ret[0]));

  for (i = 1; i <= fsi.max_id && j < fsi.num_devices; i++)
    {
      struct btrfs_ioctl_dev_info_args devi;
      memset (&devi, 0, sizeof (devi));
      devi.devid = i;
      if (ioctl (fd, BTRFS_IOC_DEV_INFO, &devi) < 0)
	{
	  close (fd);
	  free (ret);
	  return NULL;
	}
      ret[j++] = xstrdup ((char *) devi.path);
      if (j >= fsi.num_devices)
	break;
    }
  close (fd);
  ret[j] = 0;
  return ret;
}

char **
grub_find_root_devices_from_mountinfo (const char *dir, char **relroot)
{
  FILE *fp;
  char *buf = NULL;
  size_t len = 0;
  grub_size_t entry_len = 0, entry_max = 4;
  struct mountinfo_entry *entries;
  struct mountinfo_entry parent_entry = { 0, 0, 0, "", "", "", "" };
  int i;

  if (! *dir)
    dir = "/";
  if (relroot)
    *relroot = NULL;

  fp = fopen ("/proc/self/mountinfo", "r");
  if (! fp)
    return NULL; /* fall through to other methods */

  entries = xmalloc (entry_max * sizeof (*entries));

  /* First, build a list of relevant visible mounts.  */
  while (getline (&buf, &len, fp) > 0)
    {
      struct mountinfo_entry entry;
      int count;
      size_t enc_path_len;
      const char *sep;

      if (sscanf (buf, "%d %d %u:%u %s %s%n",
		  &entry.id, &parent_entry.id, &entry.major, &entry.minor,
		  entry.enc_root, entry.enc_path, &count) < 6)
	continue;

      unescape (entry.enc_root);
      unescape (entry.enc_path);

      enc_path_len = strlen (entry.enc_path);
      /* Check that enc_path is a prefix of dir.  The prefix must either be
         the entire string, or end with a slash, or be immediately followed
         by a slash.  */
      if (strncmp (dir, entry.enc_path, enc_path_len) != 0 ||
	  (enc_path_len && dir[enc_path_len - 1] != '/' &&
	   dir[enc_path_len] && dir[enc_path_len] != '/'))
	continue;

      sep = strstr (buf + count, " - ");
      if (!sep)
	continue;

      sep += sizeof (" - ") - 1;
      if (sscanf (sep, "%s %s", entry.fstype, entry.device) != 2)
	continue;

      unescape (entry.device);

      /* Using the mount IDs, find out where this fits in the list of
	 visible mount entries we've seen so far.  There are three
	 interesting cases.  Firstly, it may be inserted at the end: this is
	 the usual case of /foo/bar being mounted after /foo.  Secondly, it
	 may be inserted at the start: for example, this can happen for
	 filesystems that are mounted before / and later moved under it.
	 Thirdly, it may occlude part or all of the existing filesystem
	 tree, in which case the end of the list needs to be pruned and this
	 new entry will be inserted at the end.  */
      if (entry_len >= entry_max)
	{
	  entry_max <<= 1;
	  entries = xrealloc (entries, entry_max * sizeof (*entries));
	}

      if (!entry_len)
	{
	  /* Initialise list.  */
	  entry_len = 2;
	  entries[0] = parent_entry;
	  entries[1] = entry;
	}
      else
	{
	  for (i = entry_len - 1; i >= 0; i--)
	    {
	      if (entries[i].id == parent_entry.id)
		{
		  /* Insert at end, pruning anything previously above this.  */
		  entry_len = i + 2;
		  entries[i + 1] = entry;
		  break;
		}
	      else if (i == 0 && entries[i].id == entry.id)
		{
		  /* Insert at start.  */
		  entry_len++;
		  memmove (entries + 1, entries,
			   (entry_len - 1) * sizeof (*entries));
		  entries[0] = parent_entry;
		  entries[1] = entry;
		  break;
		}
	    }
	}
    }

  /* Now scan visible mounts for the ones we're interested in.  */
  for (i = entry_len - 1; i >= 0; i--)
    {
      char **ret = NULL;
      if (!*entries[i].device)
	continue;

      if (grub_strcmp (entries[i].fstype, "fuse.zfs") == 0
	  || grub_strcmp (entries[i].fstype, "zfs") == 0)
	{
	  char *slash;
	  slash = strchr (entries[i].device, '/');
	  if (slash)
	    *slash = 0;
	  ret = grub_util_find_root_devices_from_poolname (entries[i].device);
	  if (slash)
	    *slash = '/';
	  if (relroot)
	    {
	      if (!slash)
		*relroot = xasprintf ("/@%s", entries[i].enc_root);
	      else if (strchr (slash + 1, '@'))
		*relroot = xasprintf ("/%s%s", slash + 1, entries[i].enc_root);
	      else
		*relroot = xasprintf ("/%s@%s", slash + 1, entries[i].enc_root);
	    }
	}
      else if (grub_strcmp (entries[i].fstype, "btrfs") == 0)
	{
	  ret = grub_find_root_devices_from_btrfs (dir);
	  if (relroot)
	    {
	      char *ptr;
	      *relroot = xmalloc (strlen (entries[i].enc_root) +
				  2 + strlen (dir));
	      ptr = grub_stpcpy (*relroot, entries[i].enc_root);
	      if (strlen (dir) > strlen (entries[i].enc_path))
		{
		  while (ptr > *relroot && *(ptr - 1) == '/')
		    ptr--;
		  if (dir[strlen (entries[i].enc_path)] != '/')
		    *ptr++ = '/';
		  ptr = grub_stpcpy (ptr, dir + strlen (entries[i].enc_path));
		}
	      *ptr = 0;
	    }
	}
      if (!ret)
	{
	  ret = xmalloc (2 * sizeof (ret[0]));
	  ret[0] = strdup (entries[i].device);
	  ret[1] = 0;
	  if (relroot)
	    *relroot = strdup (entries[i].enc_root);
	}
	free (buf);
	free (entries);
	fclose (fp);
	return ret;
    }

  free (buf);
  free (entries);
  fclose (fp);
  return NULL;
}

static char *
get_mdadm_uuid (const char *os_dev)
{
  char *argv[5];
  int fd;
  pid_t pid;
  FILE *mdadm;
  char *buf = NULL;
  size_t len = 0;
  char *name = NULL;

  /* 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;

  pid = grub_util_exec_pipe (argv, &fd);

  if (!pid)
    return NULL;

  /* Parent.  Read mdadm's output.  */
  mdadm = fdopen (fd, "r");
  if (! mdadm)
    {
      grub_util_warn (_("Unable to open stream from %s: %s"),
		      "mdadm", strerror (errno));
      goto out;
    }

  while (getline (&buf, &len, mdadm) > 0)
    {
      if (strncmp (buf, "MD_UUID=", sizeof ("MD_UUID=") - 1) == 0)
	{
	  char *name_start, *ptri, *ptro;
	  
	  free (name);
	  name_start = buf + sizeof ("MD_UUID=") - 1;
	  ptro = name = xmalloc (strlen (name_start) + 1);
	  for (ptri = name_start; *ptri && *ptri != '\n' && *ptri != '\r';
	       ptri++)
	    if ((*ptri >= '0' && *ptri <= '9')
		|| (*ptri >= 'a' && *ptri <= 'f')
		|| (*ptri >= 'A' && *ptri <= 'F'))
	      *ptro++ = *ptri;
	  *ptro = 0;
	}
    }

out:
  close (fd);
  waitpid (pid, NULL, 0);
  free (buf);

  return name;
}

static int
grub_util_is_imsm (const char *os_dev)
{
  int retry;
  int is_imsm = 0;
  int container_seen = 0;
  const char *dev = os_dev;

  do
    {
      char *argv[5];
      int fd;
      pid_t pid;
      FILE *mdadm;
      char *buf = NULL;
      size_t len = 0;

      retry = 0; /* We'll do one more pass if device is part of container */

      /* 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 *) dev;
      argv[4] = NULL;

      pid = grub_util_exec_pipe (argv, &fd);

      if (!pid)
	{
	  if (dev != os_dev)
	    free ((void *) dev);
	  return 0;
	}

      /* Parent.  Read mdadm's output.  */
      mdadm = fdopen (fd, "r");
      if (! mdadm)
	{
	  grub_util_warn (_("Unable to open stream from %s: %s"),
			  "mdadm", strerror (errno));
	  close (fd);
	  waitpid (pid, NULL, 0);
	  if (dev != os_dev)
	    free ((void *) dev);
	  return 0;
	}

      while (getline (&buf, &len, mdadm) > 0)
	{
	  if (strncmp (buf, "MD_CONTAINER=", sizeof ("MD_CONTAINER=") - 1) == 0
	      && !container_seen)
	    {
	      char *newdev, *ptr;
	      newdev = xstrdup (buf + sizeof ("MD_CONTAINER=") - 1);
	      ptr = newdev + strlen (newdev) - 1;
	      for (; ptr >= newdev && (*ptr == '\n' || *ptr == '\r'); ptr--);
	      ptr[1] = 0;
	      grub_util_info ("Container of %s is %s", dev, newdev);
	      dev = newdev;
	      container_seen = retry = 1;
	      break;
	    }
	  if (strncmp (buf, "MD_METADATA=imsm",
		       sizeof ("MD_METADATA=imsm") - 1) == 0)
	    {
	      is_imsm = 1;
	      grub_util_info ("%s is imsm", dev);	      
	      break;
	    }
	}

      free (buf);
      close (fd);
      waitpid (pid, NULL, 0);
    }
  while (retry);

  if (dev != os_dev)
    free ((void *) dev);
  return is_imsm;
}

char *
grub_util_part_to_disk (const char *os_dev, struct stat *st,
			int *is_part)
{
  char *path = xmalloc (PATH_MAX);

  if (! realpath (os_dev, path))
    return NULL;

  if (strncmp ("/dev/", path, 5) == 0)
    {
      char *p = path + 5;

      /* If this is an IDE disk.  */
      if (strncmp ("ide/", p, 4) == 0)
	{
	  p = strstr (p, "part");
	  if (p)
	    {
	      *is_part = 1;
	      strcpy (p, "disc");
	    }

	  return path;
	}

      /* If this is a SCSI disk.  */
      if (strncmp ("scsi/", p, 5) == 0)
	{
	  p = strstr (p, "part");
	  if (p)
	    {
	      *is_part = 1;
	      strcpy (p, "disc");
	    }

	  return path;
	}

      /* If this is a DAC960 disk.  */
      if (strncmp ("rd/c", p, 4) == 0)
	{
	  /* /dev/rd/c[0-9]+d[0-9]+(p[0-9]+)? */
	  p = strchr (p, 'p');
	  if (p)
	    {
	      *is_part = 1;
	      *p = '\0';
	    }

	  return path;
	}

      /* If this is a Mylex AcceleRAID Array.  */
      if (strncmp ("rs/c", p, 4) == 0)
	{
	  /* /dev/rd/c[0-9]+d[0-9]+(p[0-9]+)? */
	  p = strchr (p, 'p');
	  if (p)
	    {
	      *is_part = 1;
	      *p = '\0';
	    }

	  return path;
	}
      /* If this is a CCISS disk.  */
      if (strncmp ("cciss/c", p, sizeof ("cciss/c") - 1) == 0)
	{
	  /* /dev/cciss/c[0-9]+d[0-9]+(p[0-9]+)? */
	  p = strchr (p, 'p');
	  if (p)
	    {
	      *is_part = 1;
	      *p = '\0';
	    }

	  return path;
	}

      /* If this is an AOE disk.  */
      if (strncmp ("etherd/e", p, sizeof ("etherd/e") - 1) == 0)
	{
	  /* /dev/etherd/e[0-9]+\.[0-9]+(p[0-9]+)? */
	  p = strchr (p, 'p');
	  if (p)
	    {
	      *is_part = 1;
	      *p = '\0';
	    }

	  return path;
	}

      /* If this is a Compaq Intelligent Drive Array.  */
      if (strncmp ("ida/c", p, sizeof ("ida/c") - 1) == 0)
	{
	  /* /dev/ida/c[0-9]+d[0-9]+(p[0-9]+)? */
	  p = strchr (p, 'p');
	  if (p)
	    {
	      *is_part = 1;
	      *p = '\0';
	    }

	  return path;
	}

      /* If this is an I2O disk.  */
      if (strncmp ("i2o/hd", p, sizeof ("i2o/hd") - 1) == 0)
      	{
	  /* /dev/i2o/hd[a-z]([0-9]+)? */
	  if (p[sizeof ("i2o/hda") - 1])
	    *is_part = 1;
	  p[sizeof ("i2o/hda") - 1] = '\0';
	  return path;
	}

      /* If this is a MultiMediaCard (MMC).  */
      if (strncmp ("mmcblk", p, sizeof ("mmcblk") - 1) == 0)
	{
	  /* /dev/mmcblk[0-9]+(p[0-9]+)? */
	  p = strchr (p, 'p');
	  if (p)
	    {
	      *is_part = 1;
	      *p = '\0';
	    }

	  return path;
	}

      if (strncmp ("md", p, 2) == 0
	  && p[2] >= '0' && p[2] <= '9')
	{
	  char *ptr = p + 2;
	  while (*ptr >= '0' && *ptr <= '9')
	    ptr++;
	  if (*ptr)
	    *is_part = 1;
	  *ptr = 0;
	  return path;
	}

      if (strncmp ("nbd", p, 3) == 0
	  && p[3] >= '0' && p[3] <= '9')
	{
	  char *ptr = p + 3;
	  while (*ptr >= '0' && *ptr <= '9')
	    ptr++;
	  if (*ptr)
	    *is_part = 1;
	  *ptr = 0;
	  return path;
	}

      /* If this is an IDE, SCSI or Virtio disk.  */
      if (strncmp ("vdisk", p, 5) == 0
	  && p[5] >= 'a' && p[5] <= 'z')
	{
	  /* /dev/vdisk[a-z][0-9]* */
	  if (p[6])
	    *is_part = 1;
	  p[6] = '\0';
	  return path;
	}
      if ((strncmp ("hd", p, 2) == 0
	   || strncmp ("vd", p, 2) == 0
	   || strncmp ("sd", p, 2) == 0)
	  && p[2] >= 'a' && p[2] <= 'z')
	{
	  char *pp = p + 2;
	  while (*pp >= 'a' && *pp <= 'z')
	    pp++;
	  if (*pp)
	    *is_part = 1;
	  /* /dev/[hsv]d[a-z]+[0-9]* */
	  *pp = '\0';
	  return path;
	}

      /* If this is a Xen virtual block device.  */
      if ((strncmp ("xvd", p, 3) == 0) && p[3] >= 'a' && p[3] <= 'z')
	{
	  char *pp = p + 3;
	  while (*pp >= 'a' && *pp <= 'z')
	    pp++;
	  if (*pp)
	    *is_part = 1;
	  /* /dev/xvd[a-z]+[0-9]* */
	  *pp = '\0';
	  return path;
	}
    }

  return path;
}

char *
grub_util_get_raid_grub_dev (const char *os_dev)
{
  char *grub_dev = NULL;
  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);

  {
    char *mdadm_name = get_mdadm_uuid (os_dev);

    if (mdadm_name)
      {
	const char *q;

	for (q = os_dev + strlen (os_dev) - 1; q >= os_dev
	       && grub_isdigit (*q); q--);

	if (q >= os_dev && *q == 'p')
	  {
	    free (grub_dev);
	    grub_dev = xasprintf ("mduuid/%s,%s", mdadm_name, q + 1);
	    goto done;
	  }
	free (grub_dev);
	grub_dev = xasprintf ("mduuid/%s", mdadm_name);

      done:
	free (mdadm_name);
      }
  }
  return grub_dev;
}

enum grub_dev_abstraction_types
grub_util_get_dev_abstraction_os (const char *os_dev)
{
#ifndef HAVE_DEVICE_MAPPER
  if ((strncmp ("/dev/mapper/", os_dev, 12) == 0))
    return GRUB_DEV_ABSTRACTION_LVM;
#endif

  /* Check for RAID.  */
  if (!strncmp (os_dev, "/dev/md", 7) && ! grub_util_device_is_mapped (os_dev)
      && !grub_util_is_imsm (os_dev))
    return GRUB_DEV_ABSTRACTION_RAID;
  return GRUB_DEV_ABSTRACTION_NONE;
}

int
grub_util_pull_device_os (const char *os_dev,
			  enum grub_dev_abstraction_types ab)
{
  switch (ab)
    {
    case GRUB_DEV_ABSTRACTION_RAID:
      {
	char **devicelist = grub_util_raid_getmembers (os_dev, 0);
	int i;
	for (i = 0; devicelist[i];i++)
	  {
	    grub_util_pull_device (devicelist[i]);
	    free (devicelist[i]);
	  }
	free (devicelist);
      }
      return 1;
    default:
      return 0;
    }
}

char *
grub_util_get_grub_dev_os (const char *os_dev)
{
  char *grub_dev = NULL;

  switch (grub_util_get_dev_abstraction (os_dev))
    {
      /* Fallback for non-devmapper build. In devmapper-builds LVM is handled
	 in rub_util_get_devmapper_grub_dev and this point isn't reached.
       */
    case GRUB_DEV_ABSTRACTION_LVM:
      {
	unsigned short len;
	grub_size_t offset = sizeof (LVM_DEV_MAPPER_STRING) - 1;

	len = strlen (os_dev) - offset + 1;
	grub_dev = xmalloc (len + sizeof ("lvm/"));

	grub_memcpy (grub_dev, "lvm/", sizeof ("lvm/") - 1);
	grub_memcpy (grub_dev + sizeof ("lvm/") - 1, os_dev + offset, len);
      }
      break;

    case GRUB_DEV_ABSTRACTION_RAID:
      grub_dev = grub_util_get_raid_grub_dev (os_dev);
      break;

    default:  /* GRUB_DEV_ABSTRACTION_NONE */
      break;
    }

  return grub_dev;
}