/*

 * lvm 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"

#ifndef LVM_BLK_MAJOR

# define LVM_BLK_MAJOR     58

#endif

static int is_lvm_device(dev_t devno)

{

  if (major(devno) == LVM_BLK_MAJOR)

    return 1;

  return blkid_driver_has_major("lvm", major(devno));

}

static int probe_lvm_tp(blkid_probe pr,

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

{

  const char * const paths[] = {

    "/usr/local/sbin/lvdisplay",

    "/usr/sbin/lvdisplay",

    "/sbin/lvdisplay"

  };

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

  FILE *stream = NULL;

  char *cmd = NULL, *devname = NULL, buf[1024];

  size_t i;

  dev_t devno = blkid_probe_get_devno(pr);

  if (!devno)

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

  if (!is_lvm_device(devno))

    goto nothing;

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

    struct stat sb;

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

      cmd = (char *) paths[i];

      break;

    }

  }

  if (!cmd)

    goto nothing;

  devname = blkid_devno_to_devname(devno);

  if (!devname)

    goto nothing;

  if (pipe(lvpipe) < 0) {

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

    goto nothing;

  }

  switch (fork()) {

  case 0:

  {

    char *lvargv[3];

    /* Plumbing */

    close(lvpipe[0]);

    if (lvpipe[1] != STDOUT_FILENO)

      dup2(lvpipe[1], STDOUT_FILENO);

    if (drop_permissions() != 0)

       _exit(1);

    lvargv[0] = cmd;

    lvargv[1] = devname;

    lvargv[2] = NULL;

    execv(lvargv[0], lvargv);

    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(lvpipe[0], "r" UL_CLOEXECSTR);

  if (!stream)

    goto nothing;

  while (fgets(buf, sizeof(buf), stream) != NULL) {

    if (!strncmp(buf, "Stripes", 7))

      ignore_result( sscanf(buf, "Stripes %d", &stripes) );

    if (!strncmp(buf, "Stripe size", 11))

      ignore_result( sscanf(buf, "Stripe size (KByte) %d", &stripesize) );

  }

  if (!stripes)

    goto nothing;

  blkid_topology_set_minimum_io_size(pr, stripesize << 10);

  blkid_topology_set_optimal_io_size(pr, (stripes * stripesize) << 10);

  free(devname);

  fclose(stream);

  close(lvpipe[1]);

  return 0;

nothing:

  free(devname);

  if (stream)

    fclose(stream);

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

    close(lvpipe[0]);

  if (lvpipe[1] != -1)

    close(lvpipe[1]);

  return 1;

}

const struct blkid_idinfo lvm_tp_idinfo =

{

  .name   = "lvm",

  .probefunc  = probe_lvm_tp,

  .magics   = BLKID_NONE_MAGIC

};