Example #1
0
/* Determine where the shmfs is mounted (if at all).  */
static void
where_is_shmfs (void)
{
  char buf[512];
  struct statfs f;
  struct mntent resmem;
  struct mntent *mp;
  FILE *fp;

  /* The canonical place is /dev/shm.  This is at least what the
     documentation tells everybody to do.  */
  if (__statfs (defaultdir, &f) == 0 && f.f_type == SHMFS_SUPER_MAGIC)
    {
      /* It is in the normal place.  */
      mountpoint.dir = (char *) defaultdir;
      mountpoint.dirlen = sizeof (defaultdir) - 1;

      return;
    }

  /* OK, do it the hard way.  Look through the /proc/mounts file and if
     this does not exist through /etc/fstab to find the mount point.  */
  fp = __setmntent ("/proc/mounts", "r");
  if (__builtin_expect (fp == NULL, 0))
    {
      fp = __setmntent (_PATH_MNTTAB, "r");
      if (__builtin_expect (fp == NULL, 0))
	/* There is nothing we can do.  Blind guesses are not helpful.  */
	return;
    }

  /* Now read the entries.  */
  while ((mp = __getmntent_r (fp, &resmem, buf, sizeof buf)) != NULL)
    /* The original name is "shm" but this got changed in early Linux
       2.4.x to "tmpfs".  */
    if (strcmp (mp->mnt_type, "tmpfs") == 0
	|| strcmp (mp->mnt_type, "shm") == 0)
      {
	/* Found it.  There might be more than one place where the
           filesystem is mounted but one is enough for us.  */
	size_t namelen;

	/* First make sure this really is the correct entry.  At least
	   some versions of the kernel give wrong information because
	   of the implicit mount of the shmfs for SysV IPC.  */
	if (__statfs (mp->mnt_dir, &f) != 0 || f.f_type != SHMFS_SUPER_MAGIC)
	  continue;

	namelen = strlen (mp->mnt_dir);

	if (namelen == 0)
	  /* Hum, maybe some crippled entry.  Keep on searching.  */
	  continue;

	mountpoint.dir = (char *) malloc (namelen + 2);
	if (mountpoint.dir != NULL)
	  {
	    char *cp = __mempcpy (mountpoint.dir, mp->mnt_dir, namelen);
	    if (cp[-1] != '/')
	      *cp++ = '/';
	    *cp = '\0';
	    mountpoint.dirlen = cp - mountpoint.dir;
	  }

	break;
      }

  /* Close the stream.  */
  __endmntent (fp);
}
Example #2
0
int
__statvfs_getflags (const char *name, int fstype, struct stat64 *st)
{
  if (st == NULL)
    return 0;

  const char *fsname = NULL;
  const char *fsname2 = NULL;

  /* Map the filesystem type we got from the statfs call to a string.  */
  switch (fstype)
    {
    case EXT2_SUPER_MAGIC:
      fsname = "ext3";
      fsname2 = "ext2";
      break;
    case DEVPTS_SUPER_MAGIC:
      fsname= "devpts";
      break;
    case SHMFS_SUPER_MAGIC:
      fsname = "tmpfs";
      break;
    case PROC_SUPER_MAGIC:
      fsname = "proc";
      break;
    case USBDEVFS_SUPER_MAGIC:
      fsname = "usbdevfs";
      break;
    case AUTOFS_SUPER_MAGIC:
      fsname = "autofs";
      break;
    case NFS_SUPER_MAGIC:
      fsname = "nfs";
      break;
    case SYSFS_MAGIC:
      fsname = "sysfs";
      break;
    case REISERFS_SUPER_MAGIC:
      fsname = "reiserfs";
      break;
    case XFS_SUPER_MAGIC:
      fsname = "xfs";
      break;
    case JFS_SUPER_MAGIC:
      fsname = "jfs";
      break;
    case HPFS_SUPER_MAGIC:
      fsname = "hpfs";
      break;
    case DEVFS_SUPER_MAGIC:
      fsname = "devfs";
      break;
    case ISOFS_SUPER_MAGIC:
      fsname = "iso9660";
      break;
    case MSDOS_SUPER_MAGIC:
      fsname = "msdos";
      break;
    case NTFS_SUPER_MAGIC:
      fsname = "ntfs";
      break;
    }

  FILE *mtab = __setmntent ("/proc/mounts", "r");
  if (mtab == NULL)
    mtab = __setmntent (_PATH_MOUNTED, "r");

  int result = 0;
  if (mtab != NULL)
    {
      bool success = false;
      struct mntent mntbuf;
      char tmpbuf[1024];

      /* No locking needed.  */
      (void) __fsetlocking (mtab, FSETLOCKING_BYCALLER);

    again:
      while (__getmntent_r (mtab, &mntbuf, tmpbuf, sizeof (tmpbuf)))
	{
	  /* In a first round we look for a given mount point, if
	     we have a name.  */
	  if (name != NULL && strcmp (name, mntbuf.mnt_dir) != 0)
	    continue;
	  /* We need to look at the entry only if the filesystem
	     name matches.  If we have a filesystem name.  */
	  else if (fsname != NULL
		   && strcmp (fsname, mntbuf.mnt_type) != 0
		   && (fsname2 == NULL
		       || strcmp (fsname2, mntbuf.mnt_type) != 0))
	    continue;

	  /* Find out about the device the current entry is for.  */
	  struct stat64 fsst;
	  if (stat64 (mntbuf.mnt_dir, &fsst) >= 0
	      && st->st_dev == fsst.st_dev)
	    {
	      /* Bingo, we found the entry for the device FD is on.
		 Now interpret the option string.  */
	      char *cp = mntbuf.mnt_opts;
	      char *opt;

	      while ((opt = strsep (&cp, ",")) != NULL)
		if (strcmp (opt, "ro") == 0)
		  result |= ST_RDONLY;
		else if (strcmp (opt, "nosuid") == 0)
		  result |= ST_NOSUID;
		else if (strcmp (opt, "noexec") == 0)
		  result |= ST_NOEXEC;
		else if (strcmp (opt, "nodev") == 0)
		  result |= ST_NODEV;
		else if (strcmp (opt, "sync") == 0)
		  result |= ST_SYNCHRONOUS;
		else if (strcmp (opt, "mand") == 0)
		  result |= ST_MANDLOCK;
		else if (strcmp (opt, "noatime") == 0)
		  result |= ST_NOATIME;
		else if (strcmp (opt, "nodiratime") == 0)
		  result |= ST_NODIRATIME;
		else if (strcmp (opt, "relatime") == 0)
		  result |= ST_RELATIME;

	      /* We can stop looking for more entries.  */
	      success = true;
	      break;
	    }
	}
      /* Maybe the kernel names for the filesystems changed or the
	 statvfs call got a name which was not the mount point.  Check
	 again, this time without checking for name matches first.  */
      if (! success && (name != NULL || fsname != NULL))
	{
	  if (name != NULL)
	    /* Try without a mount point name.  */
	    name = NULL;
	  else
	    {
	      /* Try without a filesystem name.  */
	      assert (fsname != NULL);
	      fsname = fsname2 = NULL;
	    }

	  /* It is not strictly allowed to use rewind here.  But
	     this code is part of the implementation so it is
	     acceptable.  */
	  rewind (mtab);

	  goto again;
	}

      /* Close the file.  */
      __endmntent (mtab);
    }

  return result;
}
Example #3
0
static long int
distinguish_extX (const struct statfs *fsbuf, const char *file, int fd)
{
  char buf[64];
  char path[PATH_MAX];
  struct stat64 st;

  if ((file == NULL ? fstat64 (fd, &st) : stat64 (file, &st)) != 0)
    /* Strange.  The statfd call worked, but stat fails.  Default to
       the more pessimistic value.  */
    return EXT2_LINK_MAX;

  __snprintf (buf, sizeof (buf), "/sys/dev/block/%u:%u",
	      gnu_dev_major (st.st_dev), gnu_dev_minor (st.st_dev));

  ssize_t n = __readlink (buf, path, sizeof (path));
  if (n != -1 && n < sizeof (path))
    {
      path[n] = '\0';
      char *base = strdupa (basename (path));
      __snprintf (path, sizeof (path), "/sys/fs/ext4/%s", base);

      return __access (path, F_OK) == 0 ? EXT4_LINK_MAX : EXT2_LINK_MAX;
    }

  /* XXX Is there a better way to distinguish ext2/3 from ext4 than
     iterating over the mounted filesystems and compare the device
     numbers?  */
  FILE *mtab = __setmntent ("/proc/mounts", "r");
  if (mtab == NULL)
    mtab = __setmntent (_PATH_MOUNTED, "r");

  /* By default be conservative.  */
  long int result = EXT2_LINK_MAX;
  if (mtab != NULL)
    {
      struct mntent mntbuf;
      char tmpbuf[1024];

      /* No locking needed.  */
      (void) __fsetlocking (mtab, FSETLOCKING_BYCALLER);

      while (__getmntent_r (mtab, &mntbuf, tmpbuf, sizeof (tmpbuf)))
	{
	  if (strcmp (mntbuf.mnt_type, "ext2") != 0
	      && strcmp (mntbuf.mnt_type, "ext3") != 0
	      && strcmp (mntbuf.mnt_type, "ext4") != 0)
	    continue;

	  struct stat64 fsst;
	  if (stat64 (mntbuf.mnt_dir, &fsst) >= 0
	      && st.st_dev == fsst.st_dev)
	    {
	      if (strcmp (mntbuf.mnt_type, "ext4") == 0)
		result = EXT4_LINK_MAX;
	      break;
	    }
	}

      /* Close the file.  */
      __endmntent (mtab);
    }

  return result;
}