/*

 * devname.c - get a dev by its device inode name

 *

 * Copyright (C) Andries Brouwer

 * Copyright (C) 1999, 2000, 2001, 2002, 2003 Theodore Ts'o

 * Copyright (C) 2001 Andreas Dilger

 *

 * %Begin-Header%

 * This file may be redistributed under the terms of the

 * GNU Lesser General Public License.

 * %End-Header%

 */

#define _GNU_SOURCE 1

#include <stdio.h>

#include <string.h>

#include <limits.h>

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#include <stdlib.h>

#include <ctype.h>

#include <fcntl.h>

#ifdef HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif

#include <dirent.h>

#ifdef HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#ifdef HAVE_ERRNO_H

#include <errno.h>

#endif

#include <time.h>

#include "blkidP.h"

#include "canonicalize.h"   /* $(top_srcdir)/include */

#include "pathnames.h"

#include "sysfs.h"

#include "fileutils.h"

/*

 * Find a dev struct in the cache by device name, if available.

 *

 * If there is no entry with the specified device name, and the create

 * flag is set, then create an empty device entry.

 */

blkid_dev blkid_get_dev(blkid_cache cache, const char *devname, int flags)

{

  blkid_dev dev = NULL, tmp;

  struct list_head *p, *pnext;

  char *cn = NULL;

  if (!cache || !devname)

    return NULL;

  /* search by name */

  list_for_each(p, &cache->bic_devs) {

    tmp = list_entry(p, struct blkid_struct_dev, bid_devs);

    if (strcmp(tmp->bid_name, devname) != 0)

      continue;

    dev = tmp;

    break;

  }

  /* try canonicalize the name */

  if (!dev && (cn = canonicalize_path(devname))) {

    if (strcmp(cn, devname) != 0) {

      DBG(DEVNAME, ul_debug("search canonical %s", cn));

      list_for_each(p, &cache->bic_devs) {

        tmp = list_entry(p, struct blkid_struct_dev, bid_devs);

        if (strcmp(tmp->bid_name, cn) != 0)

          continue;

        dev = tmp;

        /* update name returned by blkid_dev_devname() */

        free(dev->bid_xname);

        dev->bid_xname = strdup(devname);

        break;

      }

    } else {

      free(cn);

      cn = NULL;

    }

  }

  if (!dev && (flags & BLKID_DEV_CREATE)) {

    if (access(devname, F_OK) < 0)

      goto done;

    dev = blkid_new_dev();

    if (!dev)

      goto done;

    dev->bid_time = (uintmax_t)1 << (sizeof(time_t) * 8 - 1);

    if (cn) {

      dev->bid_name = cn;

      dev->bid_xname = strdup(devname);

      cn = NULL;  /* see free() below */

    } else

      dev->bid_name = strdup(devname);

    dev->bid_cache = cache;

    list_add_tail(&dev->bid_devs, &cache->bic_devs);

    cache->bic_flags |= BLKID_BIC_FL_CHANGED;

  }

  if (flags & BLKID_DEV_VERIFY) {

    dev = blkid_verify(cache, dev);

    if (!dev || !(dev->bid_flags & BLKID_BID_FL_VERIFIED))

      goto done;

    /*

     * If the device is verified, then search the blkid

     * cache for any entries that match on the type, uuid,

     * and label, and verify them; if a cache entry can

     * not be verified, then it's stale and so we remove

     * it.

     */

    list_for_each_safe(p, pnext, &cache->bic_devs) {

      blkid_dev dev2 = list_entry(p, struct blkid_struct_dev, bid_devs);

      if (dev2->bid_flags & BLKID_BID_FL_VERIFIED)

        continue;

      if (!dev->bid_type || !dev2->bid_type ||

          strcmp(dev->bid_type, dev2->bid_type) != 0)

        continue;

      if (dev->bid_label && dev2->bid_label &&

          strcmp(dev->bid_label, dev2->bid_label) != 0)

        continue;

      if (dev->bid_uuid && dev2->bid_uuid &&

          strcmp(dev->bid_uuid, dev2->bid_uuid) != 0)

        continue;

      if ((dev->bid_label && !dev2->bid_label) ||

          (!dev->bid_label && dev2->bid_label) ||

          (dev->bid_uuid && !dev2->bid_uuid) ||

          (!dev->bid_uuid && dev2->bid_uuid))

        continue;

      dev2 = blkid_verify(cache, dev2);

      if (dev2 && !(dev2->bid_flags & BLKID_BID_FL_VERIFIED))

        blkid_free_dev(dev2);

    }

  }

done:

  if (dev)

    DBG(DEVNAME, ul_debug("%s requested, found %s in cache", devname, dev->bid_name));

  free(cn);

  return dev;

}

/* Directories where we will try to search for device names */

static const char *const dirlist[] = { "/dev", "/devfs", "/devices", NULL };

/*

 * Return 1 if the device is a device-mapper 'leaf' node

 * not holding any other devices in its hierarchy.

 */

static int is_dm_leaf(const char *devname)

{

  DIR *dir;

  char path[NAME_MAX + 18 + 1];

  int ret;

  snprintf(path, sizeof(path), "/sys/block/%s/holders", devname);

  if ((dir = opendir(path)) == NULL)

    return 0;

  ret = xreaddir(dir) == NULL ? 1 : 0; /* 'leaf' has no entries */

  closedir(dir);

  return ret;

}

/*

 * Probe a single block device to add to the device cache.

 */

static void probe_one(blkid_cache cache, const char *ptname,

          dev_t devno, int pri, int only_if_new, int removable)

{

  blkid_dev dev = NULL;

  struct list_head *p, *pnext;

  const char *const*dir;

  char *devname = NULL;

  /* See if we already have this device number in the cache. */

  list_for_each_safe(p, pnext, &cache->bic_devs) {

    blkid_dev tmp = list_entry(p, struct blkid_struct_dev,

             bid_devs);

    if (tmp->bid_devno == devno) {

      if (only_if_new && !access(tmp->bid_name, F_OK))

        return;

      dev = blkid_verify(cache, tmp);

      if (dev && (dev->bid_flags & BLKID_BID_FL_VERIFIED))

        break;

      dev = NULL;

    }

  }

  if (dev && dev->bid_devno == devno)

    goto set_pri;

  /* Try to translate private device-mapper dm-<N> names

   * to standard /dev/mapper/<name>.

   */

  if (!strncmp(ptname, "dm-", 3) && isdigit(ptname[3])) {

    devname = canonicalize_dm_name(ptname);

    if (!devname)

      blkid__scan_dir("/dev/mapper", devno, NULL, &devname);

    if (devname)

      goto get_dev;

  }

  /*

   * Take a quick look at /dev/ptname for the device number.  We check

   * all of the likely device directories.  If we don't find it, or if

   * the stat information doesn't check out, use blkid_devno_to_devname()

   * to find it via an exhaustive search for the device major/minor.

   */

  for (dir = dirlist; *dir; dir++) {

    struct stat st;

    char device[256];

    snprintf(device, sizeof(device), "%s/%s", *dir, ptname);

    if ((dev = blkid_get_dev(cache, device, BLKID_DEV_FIND)) &&

        dev->bid_devno == devno)

      goto set_pri;

    if (stat(device, &st) == 0 &&

        (S_ISBLK(st.st_mode) ||

         (S_ISCHR(st.st_mode) && !strncmp(ptname, "ubi", 3))) &&

        st.st_rdev == devno) {

      devname = strdup(device);

      goto get_dev;

    }

  }

  /* Do a short-cut scan of /dev/mapper first */

  if (!devname)

    blkid__scan_dir("/dev/mapper", devno, NULL, &devname);

  if (!devname) {

    devname = blkid_devno_to_devname(devno);

    if (!devname)

      return;

  }

get_dev:

  dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);

  free(devname);

set_pri:

  if (dev) {

    if (pri)

      dev->bid_pri = pri;

    else if (!strncmp(dev->bid_name, "/dev/mapper/", 12)) {

      dev->bid_pri = BLKID_PRI_DM;

      if (is_dm_leaf(ptname))

        dev->bid_pri += 5;

    } else if (!strncmp(ptname, "md", 2))

      dev->bid_pri = BLKID_PRI_MD;

    if (removable)

      dev->bid_flags |= BLKID_BID_FL_REMOVABLE;

  }

}

#define PROC_PARTITIONS "/proc/partitions"

#define VG_DIR    "/proc/lvm/VGs"

/*

 * This function initializes the UUID cache with devices from the LVM

 * proc hierarchy.  We currently depend on the names of the LVM

 * hierarchy giving us the device structure in /dev.  (XXX is this a

 * safe thing to do?)

 */

#ifdef VG_DIR

static dev_t lvm_get_devno(const char *lvm_device)

{

  FILE *lvf;

  char buf[1024];

  int ma, mi;

  dev_t ret = 0;

  DBG(DEVNAME, ul_debug("opening %s", lvm_device));

  if ((lvf = fopen(lvm_device, "r" UL_CLOEXECSTR)) == NULL) {

    DBG(DEVNAME, ul_debug("%s: (%d) %m", lvm_device, errno));

    return 0;

  }

  while (fgets(buf, sizeof(buf), lvf)) {

    if (sscanf(buf, "device: %d:%d", &ma, &mi) == 2) {

      ret = makedev(ma, mi);

      break;

    }

  }

  fclose(lvf);

  return ret;

}

static void lvm_probe_all(blkid_cache cache, int only_if_new)

{

  DIR   *vg_list;

  struct dirent *vg_iter;

  int   vg_len = strlen(VG_DIR);

  dev_t   dev;

  if ((vg_list = opendir(VG_DIR)) == NULL)

    return;

  DBG(DEVNAME, ul_debug("probing LVM devices under %s", VG_DIR));

  while ((vg_iter = readdir(vg_list)) != NULL) {

    DIR   *lv_list;

    char    *vdirname;

    char    *vg_name;

    struct dirent *lv_iter;

    size_t    len;

    vg_name = vg_iter->d_name;

    if (!strcmp(vg_name, ".") || !strcmp(vg_name, ".."))

      continue;

    len = vg_len + strlen(vg_name) + 8;

    vdirname = malloc(len);

    if (!vdirname)

      goto exit;

    snprintf(vdirname, len, "%s/%s/LVs", VG_DIR, vg_name);

    lv_list = opendir(vdirname);

    free(vdirname);

    if (lv_list == NULL)

      continue;

    while ((lv_iter = readdir(lv_list)) != NULL) {

      char    *lv_name, *lvm_device;

      lv_name = lv_iter->d_name;

      if (!strcmp(lv_name, ".") || !strcmp(lv_name, ".."))

        continue;

      len = vg_len + strlen(vg_name) + strlen(lv_name) + 8;

      lvm_device = malloc(len);

      if (!lvm_device) {

        closedir(lv_list);

        goto exit;

      }

      snprintf(lvm_device, len, "%s/%s/LVs/%s", VG_DIR, vg_name,

        lv_name);

      dev = lvm_get_devno(lvm_device);

      snprintf(lvm_device, len, "%s/%s", vg_name, lv_name);

      DBG(DEVNAME, ul_debug("Probe LVM dev %s: devno 0x%04X",

              lvm_device,

              (unsigned int) dev));

      probe_one(cache, lvm_device, dev, BLKID_PRI_LVM,

          only_if_new, 0);

      free(lvm_device);

    }

    closedir(lv_list);

  }

exit:

  closedir(vg_list);

}

#endif

static void

ubi_probe_all(blkid_cache cache, int only_if_new)

{

  const char *const*dirname;

  for (dirname = dirlist; *dirname; dirname++) {

    DIR   *dir;

    struct dirent *iter;

    DBG(DEVNAME, ul_debug("probing UBI volumes under %s",

            *dirname));

    dir = opendir(*dirname);

    if (dir == NULL)

      continue ;

    while ((iter = readdir(dir)) != NULL) {

      char    *name;

      struct stat st;

      dev_t   dev;

      name = iter->d_name;

#ifdef _DIRENT_HAVE_D_TYPE

      if (iter->d_type != DT_UNKNOWN &&

          iter->d_type != DT_CHR && iter->d_type != DT_LNK)

        continue;

#endif

      if (!strcmp(name, ".") || !strcmp(name, "..") ||

          !strstr(name, "ubi"))

        continue;

      if (!strcmp(name, "ubi_ctrl"))

        continue;

      if (fstatat(dirfd(dir), name, &st, 0))

        continue;

      dev = st.st_rdev;

      if (!S_ISCHR(st.st_mode) || !minor(dev))

        continue;

      DBG(DEVNAME, ul_debug("Probe UBI vol %s/%s: devno 0x%04X",

          *dirname, name, (int) dev));

      probe_one(cache, name, dev, BLKID_PRI_UBI, only_if_new, 0);

    }

    closedir(dir);

  }

}

/*

 * This function uses /sys to read all block devices in way compatible with

 * /proc/partitions (like the original libblkid implementation)

 */

static int

sysfs_probe_all(blkid_cache cache, int only_if_new, int only_removable)

{

  DIR *sysfs;

  struct dirent *dev;

  sysfs = opendir(_PATH_SYS_BLOCK);

  if (!sysfs)

    return -BLKID_ERR_SYSFS;

  DBG(DEVNAME, ul_debug(" probe /sys/block"));

  /* scan /sys/block */

  while ((dev = xreaddir(sysfs))) {

    DIR *dir = NULL;

    dev_t devno;

    size_t nparts = 0;

    unsigned int maxparts = 0, removable = 0;

    struct dirent *part;

    struct path_cxt *pc = NULL;

    uint64_t size = 0;

    DBG(DEVNAME, ul_debug("checking %s", dev->d_name));

    devno = sysfs_devname_to_devno(dev->d_name);

    if (!devno)

      goto next;

    pc = ul_new_sysfs_path(devno, NULL, NULL);

    if (!pc)

      goto next;

    if (ul_path_read_u64(pc, &size, "size") != 0)

      size = 0;

    if (ul_path_read_u32(pc, &removable, "removable") != 0)

      removable = 0;

    /* ignore empty devices */

    if (!size)

      goto next;

    /* accept removable if only removable requested */

    if (only_removable) {

      if (!removable)

        goto next;

    /* emulate /proc/partitions

     * -- ignore empty devices and non-partitionable removable devices */

    } else {

      if (ul_path_read_u32(pc, &maxparts, "ext_range") != 0)

        maxparts = 0;

      if (!maxparts && removable)

        goto next;

    }

    DBG(DEVNAME, ul_debug("read device name %s", dev->d_name));

    dir = ul_path_opendir(pc, NULL);

    if (!dir)

      goto next;

    /* read /sys/block/<name>/ do get partitions */

    while ((part = xreaddir(dir))) {

      dev_t partno;

      if (!sysfs_blkdev_is_partition_dirent(dir, part, dev->d_name))

        continue;

      /* ignore extended partitions

       * -- recount size to blocks like /proc/partitions */

      if (ul_path_readf_u64(pc, &size, "%s/size", part->d_name) == 0

          && (size >> 1) == 1)

        continue;

      partno = __sysfs_devname_to_devno(NULL, part->d_name, dev->d_name);

      if (!partno)

        continue;

      DBG(DEVNAME, ul_debug(" Probe partition dev %s, devno 0x%04X",

                                   part->d_name, (unsigned int) partno));

      nparts++;

      probe_one(cache, part->d_name, partno, 0, only_if_new, 0);

    }

    if (!nparts) {

      /* add non-partitioned whole disk to cache */

      DBG(DEVNAME, ul_debug(" Probe whole dev %s, devno 0x%04X",

           dev->d_name, (unsigned int) devno));

      probe_one(cache, dev->d_name, devno, 0, only_if_new, 0);

    } else {

      /* remove partitioned whole-disk from cache */

      struct list_head *p, *pnext;

      list_for_each_safe(p, pnext, &cache->bic_devs) {

        blkid_dev tmp = list_entry(p, struct blkid_struct_dev,

              bid_devs);

        if (tmp->bid_devno == devno) {

          DBG(DEVNAME, ul_debug(" freeing %s", tmp->bid_name));

          blkid_free_dev(tmp);

          cache->bic_flags |= BLKID_BIC_FL_CHANGED;

          break;

        }

      }

    }

  next:

    if (dir)

      closedir(dir);

    if (pc)

      ul_unref_path(pc);

  }

  closedir(sysfs);

  return 0;

}

/*

 * Read the device data for all available block devices in the system.

 */

static int probe_all(blkid_cache cache, int only_if_new, int update_interval)

{

  int rc;

  if (!cache)

    return -BLKID_ERR_PARAM;

  if (cache->bic_flags & BLKID_BIC_FL_PROBED &&

      time(NULL) - cache->bic_time < BLKID_PROBE_INTERVAL) {

    DBG(PROBE, ul_debug("don't re-probe [delay < %d]", BLKID_PROBE_INTERVAL));

    return 0;

  }

  blkid_read_cache(cache);

#ifdef VG_DIR

  lvm_probe_all(cache, only_if_new);

#endif

  ubi_probe_all(cache, only_if_new);

  rc = sysfs_probe_all(cache, only_if_new, 0);

  /* Don't mark the change as "probed" if /sys not available */

  if (update_interval && rc == 0) {

    cache->bic_time = time(NULL);

    cache->bic_flags |= BLKID_BIC_FL_PROBED;

  }

  blkid_flush_cache(cache);

  return 0;

}

/**

 * blkid_probe_all:

 * @cache: cache handler

 *

 * Probes all block devices.

 *

 * Returns: 0 on success, or number less than zero in case of error.

 */

int blkid_probe_all(blkid_cache cache)

{

  int ret;

  DBG(PROBE, ul_debug("Begin blkid_probe_all()"));

  ret = probe_all(cache, 0, 1);

  DBG(PROBE, ul_debug("End blkid_probe_all() [rc=%d]", ret));

  return ret;

}

/**

 * blkid_probe_all_new:

 * @cache: cache handler

 *

 * Probes all new block devices.

 *

 * Returns: 0 on success, or number less than zero in case of error.

 */

int blkid_probe_all_new(blkid_cache cache)

{

  int ret;

  DBG(PROBE, ul_debug("Begin blkid_probe_all_new()"));

  ret = probe_all(cache, 1, 0);

  DBG(PROBE, ul_debug("End blkid_probe_all_new() [rc=%d]", ret));

  return ret;

}

/**

 * blkid_probe_all_removable:

 * @cache: cache handler

 *

 * The libblkid probing is based on devices from /proc/partitions by default.

 * This file usually does not contain removable devices (e.g. CDROMs) and this kind

 * of devices are invisible for libblkid.

 *

 * This function adds removable block devices to @cache (probing is based on

 * information from the /sys directory). Don't forget that removable devices

 * (floppies, CDROMs, ...) could be pretty slow. It's very bad idea to call

 * this function by default.

 *

 * Note that devices which were detected by this function won't be written to

 * blkid.tab cache file.

 *

 * Returns: 0 on success, or number less than zero in case of error.

 */

int blkid_probe_all_removable(blkid_cache cache)

{

  int ret;

  DBG(PROBE, ul_debug("Begin blkid_probe_all_removable()"));

  ret = sysfs_probe_all(cache, 0, 1);

  DBG(PROBE, ul_debug("End blkid_probe_all_removable() [rc=%d]", ret));

  return ret;

}

#ifdef TEST_PROGRAM

int main(int argc, char **argv)

{

  blkid_cache cache = NULL;

  int ret;

  blkid_init_debug(BLKID_DEBUG_ALL);

  if (argc != 1) {

    fprintf(stderr, "Usage: %s\n"

      "Probe all devices and exit\n", argv[0]);

    exit(1);

  }

  if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {

    fprintf(stderr, "%s: error creating cache (%d)\n",

      argv[0], ret);

    exit(1);

  }

  if (blkid_probe_all(cache) < 0)

    printf("%s: error probing devices\n", argv[0]);

  if (blkid_probe_all_removable(cache) < 0)

    printf("%s: error probing removable devices\n", argv[0]);

  blkid_put_cache(cache);

  return (0);

}

#endif