struct mntent *
getmntent (FILE *stream)
{
static struct mntent m;
__libc_once_define (static, once);
__libc_once (once, allocate);
if (getmntent_buffer == NULL)
/* If no core is available we don't have a chance to run the
program successfully and so returning NULL is an acceptable
result. */
return NULL;
return __getmntent_r (stream, &m, getmntent_buffer, BUFFER_SIZE);
}
struct mntent *
getmntent (FILE *stream)
{
static struct mntent m;
static int once;
do {
if (__pthread_once != NULL)
__pthread_once (&once, allocate);
else if (once == 0) {
allocate ();
once = !(0);
}
} while (0);
if (getmntent_buffer == NULL)
/* If no core is available we don't have a chance to run the
program successfully and so returning NULL is an acceptable
result. */
return NULL;
return __getmntent_r (stream, &m, getmntent_buffer, BUFFER_SIZE);
}
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;
}
/* 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);
}
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;
}