sysdeps/unix/sysv/linux/internal_statvfs.c

   1 /* Copyright (C) 1998-2006, 2010 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <mntent.h>
  23 #include <paths.h>
  24 #include <stdbool.h>
  25 #include <stdio_ext.h>
  26 #include <string.h>
  27 #include <sys/mount.h>
  28 #include <sys/stat.h>
  29 #include <sys/statfs.h>
  30 #include <sys/statvfs.h>
  31 #include "linux_fsinfo.h"
  32 #include "kernel-features.h"
  33
  34
  35 /* Special internal-only bit value.  */
  36 #define ST_VALID 0x0020
  37
  38
  39 #ifndef STATFS
  40 # define STATFS statfs
  41 # define STATVFS statvfs
  42 # define INTERNAL_STATVFS __internal_statvfs
  43
  44
  45 # ifndef __ASSUME_STATFS_F_FLAGS
  46 int
  47 __statvfs_getflags (const char *name, int fstype, struct stat64 *st)
  48 {
  49   if (st == NULL)
  50     return 0;
  51
  52   const char *fsname = NULL;
  53   const char *fsname2 = NULL;
  54   const char *fsname3 = NULL;
  55
  56   /* Map the filesystem type we got from the statfs call to a string.  */
  57   switch (fstype)
  58     {
  59     case EXT2_SUPER_MAGIC:
  60       fsname = "ext4";
  61       fsname2 = "ext3";
  62       fsname3 = "ext2";
  63       break;
  64     case DEVPTS_SUPER_MAGIC:
  65       fsname= "devpts";
  66       break;
  67     case SHMFS_SUPER_MAGIC:
  68       fsname = "tmpfs";
  69       break;
  70     case PROC_SUPER_MAGIC:
  71       fsname = "proc";
  72       break;
  73     case USBDEVFS_SUPER_MAGIC:
  74       fsname = "usbdevfs";
  75       break;
  76     case AUTOFS_SUPER_MAGIC:
  77       fsname = "autofs";
  78       break;
  79     case NFS_SUPER_MAGIC:
  80       fsname = "nfs";
  81       break;
  82     case SYSFS_MAGIC:
  83       fsname = "sysfs";
  84       break;
  85     case REISERFS_SUPER_MAGIC:
  86       fsname = "reiserfs";
  87       break;
  88     case XFS_SUPER_MAGIC:
  89       fsname = "xfs";
  90       break;
  91     case JFS_SUPER_MAGIC:
  92       fsname = "jfs";
  93       break;
  94     case HPFS_SUPER_MAGIC:
  95       fsname = "hpfs";
  96       break;
  97     case DEVFS_SUPER_MAGIC:
  98       fsname = "devfs";
  99       break;
 100     case ISOFS_SUPER_MAGIC:
 101       fsname = "iso9660";
 102       break;
 103     case MSDOS_SUPER_MAGIC:
 104       fsname = "msdos";
 105       break;
 106     case NTFS_SUPER_MAGIC:
 107       fsname = "ntfs";
 108       break;
 109     case LOGFS_MAGIC_U32:
 110       fsname = "logfs";
 111       break;
 112     }
 113
 114   FILE *mtab = __setmntent ("/proc/mounts", "r");
 115   if (mtab == NULL)
 116     mtab = __setmntent (_PATH_MOUNTED, "r");
 117
 118   int result = 0;
 119   if (mtab != NULL)
 120     {
 121       bool success = false;
 122       struct mntent mntbuf;
 123       char tmpbuf[1024];
 124
 125       /* No locking needed.  */
 126       (void) __fsetlocking (mtab, FSETLOCKING_BYCALLER);
 127
 128     again:
 129       while (__getmntent_r (mtab, &mntbuf, tmpbuf, sizeof (tmpbuf)))
 130         {
 131           /* In a first round we look for a given mount point, if
 132              we have a name.  */
 133           if (name != NULL && strcmp (name, mntbuf.mnt_dir) != 0)
 134             continue;
 135           /* We need to look at the entry only if the filesystem
 136              name matches.  If we have a filesystem name.  */
 137           else if (fsname != NULL
 138                    && strcmp (fsname, mntbuf.mnt_type) != 0
 139                    && (fsname2 == NULL
 140                        || strcmp (fsname2, mntbuf.mnt_type) != 0)
 141                    && (fsname3 == NULL
 142                        || strcmp (fsname3, mntbuf.mnt_type) != 0))
 143             continue;
 144
 145           /* Find out about the device the current entry is for.  */
 146           struct stat64 fsst;
 147           if (stat64 (mntbuf.mnt_dir, &fsst) >= 0
 148               && st->st_dev == fsst.st_dev)
 149             {
 150               /* Bingo, we found the entry for the device FD is on.
 151                  Now interpret the option string.  */
 152               char *cp = mntbuf.mnt_opts;
 153               char *opt;
 154
 155               while ((opt = strsep (&cp, ",")) != NULL)
 156                 if (strcmp (opt, "ro") == 0)
 157                   result |= ST_RDONLY;
 158                 else if (strcmp (opt, "nosuid") == 0)
 159                   result |= ST_NOSUID;
 160                 else if (strcmp (opt, "noexec") == 0)
 161                   result |= ST_NOEXEC;
 162                 else if (strcmp (opt, "nodev") == 0)
 163                   result |= ST_NODEV;
 164                 else if (strcmp (opt, "sync") == 0)
 165                   result |= ST_SYNCHRONOUS;
 166                 else if (strcmp (opt, "mand") == 0)
 167                   result |= ST_MANDLOCK;
 168                 else if (strcmp (opt, "noatime") == 0)
 169                   result |= ST_NOATIME;
 170                 else if (strcmp (opt, "nodiratime") == 0)
 171                   result |= ST_NODIRATIME;
 172                 else if (strcmp (opt, "relatime") == 0)
 173                   result |= ST_RELATIME;
 174
 175               /* We can stop looking for more entries.  */
 176               success = true;
 177               break;
 178             }
 179         }
 180       /* Maybe the kernel names for the filesystems changed or the
 181          statvfs call got a name which was not the mount point.  Check
 182          again, this time without checking for name matches first.  */
 183       if (! success && (name != NULL || fsname != NULL))
 184         {
 185           if (name != NULL)
 186             /* Try without a mount point name.  */
 187             name = NULL;
 188           else
 189             {
 190               /* Try without a filesystem name.  */
 191               assert (fsname != NULL);
 192               fsname = fsname2 = fsname3 = NULL;
 193             }
 194
 195           /* It is not strictly allowed to use rewind here.  But
 196              this code is part of the implementation so it is
 197              acceptable.  */
 198           rewind (mtab);
 199
 200           goto again;
 201         }
 202
 203       /* Close the file.  */
 204       __endmntent (mtab);
 205     }
 206
 207   return result;
 208 }
 209 # endif
 210 #else
 211 extern int __statvfs_getflags (const char *name, int fstype,
 212                                struct stat64 *st);
 213 #endif
 214
 215
 216 void
 217 INTERNAL_STATVFS (const char *name, struct STATVFS *buf,
 218                   struct STATFS *fsbuf, struct stat64 *st)
 219 {
 220   /* Now fill in the fields we have information for.  */
 221   buf->f_bsize = fsbuf->f_bsize;
 222   /* Linux has the f_frsize size only in later version of the kernel.
 223      If the value is not filled in use f_bsize.  */
 224   buf->f_frsize = fsbuf->f_frsize ?: fsbuf->f_bsize;
 225   buf->f_blocks = fsbuf->f_blocks;
 226   buf->f_bfree = fsbuf->f_bfree;
 227   buf->f_bavail = fsbuf->f_bavail;
 228   buf->f_files = fsbuf->f_files;
 229   buf->f_ffree = fsbuf->f_ffree;
 230   if (sizeof (buf->f_fsid) == sizeof (fsbuf->f_fsid))
 231     buf->f_fsid = (fsbuf->f_fsid.__val[0]
 232                    | ((unsigned long int) fsbuf->f_fsid.__val[1]
 233                       << (8 * (sizeof (buf->f_fsid)
 234                                - sizeof (fsbuf->f_fsid.__val[0])))));
 235   else
 236     /* We cannot help here.  The statvfs element is not large enough to
 237        contain both words of the statfs f_fsid field.  */
 238     buf->f_fsid = fsbuf->f_fsid.__val[0];
 239 #ifdef _STATVFSBUF_F_UNUSED
 240   buf->__f_unused = 0;
 241 #endif
 242   buf->f_namemax = fsbuf->f_namelen;
 243   memset (buf->__f_spare, '\0', sizeof (buf->__f_spare));
 244
 245   /* What remains to do is to fill the fields f_favail and f_flag.  */
 246
 247   /* XXX I have no idea how to compute f_favail.  Any idea???  */
 248   buf->f_favail = buf->f_ffree;
 249
 250 #ifndef __ASSUME_STATFS_F_FLAGS
 251   if ((fsbuf->f_flags & ST_VALID) == 0)
 252     /* Determining the flags is tricky.  We have to read /proc/mounts or
 253        the /etc/mtab file and search for the entry which matches the given
 254        file.  The way we can test for matching filesystem is using the
 255        device number.  */
 256     buf->f_flag = __statvfs_getflags (name, fsbuf->f_type, st);
 257   else
 258 #endif
 259     buf->f_flag = fsbuf->f_flags ^ ST_VALID;
 260 }