/*

 * device-mapper (dm) topology

 * -- this is fallback for old systems where the topology information is not

 *    exported by sysfs

 *

 * Copyright (C) 2009 Karel Zak <kzak@redhat.com>

 *

 * This file may be redistributed under the terms of the

 * GNU Lesser General Public License.

 *

 */

#include <errno.h>

#include <fcntl.h>

#include <stdint.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <unistd.h>

#include "topology.h"

static int is_dm_device(dev_t devno)

{

  return blkid_driver_has_major("device-mapper", major(devno));

}

static int probe_dm_tp(blkid_probe pr,

    const struct blkid_idmag *mag __attribute__((__unused__)))

{

  const char * const paths[] = {

    "/usr/local/sbin/dmsetup",

    "/usr/sbin/dmsetup",

    "/sbin/dmsetup"

  };

  int dmpipe[] = { -1, -1 }, stripes = 0, stripesize = 0;

  const char *cmd = NULL;

  FILE *stream = NULL;

  long long  offset = 0, size = 0;

  size_t i;

  dev_t devno = blkid_probe_get_devno(pr);

  if (!devno)

    goto nothing;   /* probably not a block device */

  if (!is_dm_device(devno))

    goto nothing;

  for (i = 0; i < ARRAY_SIZE(paths); i++) {

    struct stat sb;

    if (stat(paths[i], &sb) == 0) {

      cmd = paths[i];

      break;

    }

  }

  if (!cmd)

    goto nothing;

  if (pipe(dmpipe) < 0) {

    DBG(LOWPROBE, ul_debug("Failed to open pipe: errno=%d", errno));

    goto nothing;

  }

  switch (fork()) {

  case 0:

  {

    const char *dmargv[7];

          char maj[16], min[16];

    /* Plumbing */

    close(dmpipe[0]);

    if (dmpipe[1] != STDOUT_FILENO)

      dup2(dmpipe[1], STDOUT_FILENO);

    if (drop_permissions() != 0)

       _exit(1);

    snprintf(maj, sizeof(maj), "%d", major(devno));

    snprintf(min, sizeof(min), "%d", minor(devno));

    dmargv[0] = cmd;

    dmargv[1] = "table";

    dmargv[2] = "-j";

    dmargv[3] = maj;

    dmargv[4] = "-m";

    dmargv[5] = min;

    dmargv[6] = NULL;

    execv(dmargv[0], (char * const *) dmargv);

    DBG(LOWPROBE, ul_debug("Failed to execute %s: errno=%d", cmd, errno));

    exit(1);

  }

  case -1:

    DBG(LOWPROBE, ul_debug("Failed to forking: errno=%d", errno));

    goto nothing;

  default:

    break;

  }

  stream = fdopen(dmpipe[0], "r" UL_CLOEXECSTR);

  if (!stream)

    goto nothing;

  if (dmpipe[1] != -1) {

    close(dmpipe[1]);

  }

  if (fscanf(stream, "%lld %lld striped %d %d ",

      &offset, &size, &stripes, &stripesize) != 4)

    goto nothing;

  blkid_topology_set_minimum_io_size(pr, stripesize << 9);

  blkid_topology_set_optimal_io_size(pr, (stripes * stripesize) << 9);

  fclose(stream);

  return 0;

nothing:

  if (stream)

    fclose(stream);

  else if (dmpipe[0] != -1)

    close(dmpipe[0]);

  return 1;

}

const struct blkid_idinfo dm_tp_idinfo =

{

  .name   = "dm",

  .probefunc  = probe_dm_tp,

  .magics   = BLKID_NONE_MAGIC

};