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
  33
  34 #ifndef STATFS
  35 # define STATFS statfs
  36 # define STATVFS statvfs
  37 # define INTERNAL_STATVFS __internal_statvfs
  38
  39
  40 int
  41 __statvfs_getflags (const char *name, int fstype, struct stat64 *st)
  42 {
  43   if (st == NULL)
  44     return 0;
  45
  46   const char *fsname = NULL;
  47   const char *fsname2 = NULL;
  48   const char *fsname3 = NULL;
  49
  50   /* Map the filesystem type we got from the statfs call to a string.  */
  51   switch (fstype)
  52     {
  53     case EXT2_SUPER_MAGIC:
  54       fsname = "ext4";
  55       fsname2 = "ext3";
  56       fsname3 = "ext2";
  57       break;
  58     case DEVPTS_SUPER_MAGIC:
  59       fsname= "devpts";
  60       break;
  61     case SHMFS_SUPER_MAGIC:
  62       fsname = "tmpfs";
  63       break;
  64     case PROC_SUPER_MAGIC:
  65       fsname = "proc";
  66       break;
  67     case USBDEVFS_SUPER_MAGIC:
  68       fsname = "usbdevfs";
  69       break;
  70     case AUTOFS_SUPER_MAGIC:
  71       fsname = "autofs";
  72       break;
  73     case NFS_SUPER_MAGIC:
  74       fsname = "nfs";
  75       break;
  76     case SYSFS_MAGIC:
  77       fsname = "sysfs";
  78       break;
  79     case REISERFS_SUPER_MAGIC:
  80       fsname = "reiserfs";
  81       break;
  82     case XFS_SUPER_MAGIC:
  83       fsname = "xfs";
  84       break;
  85     case JFS_SUPER_MAGIC:
  86       fsname = "jfs";
  87       break;
  88     case HPFS_SUPER_MAGIC:
  89       fsname = "hpfs";
  90       break;
  91     case DEVFS_SUPER_MAGIC:
  92       fsname = "devfs";
  93       break;
  94     case ISOFS_SUPER_MAGIC:
  95       fsname = "iso9660";
  96       break;
  97     case MSDOS_SUPER_MAGIC:
  98       fsname = "msdos";
  99       break;
 100     case NTFS_SUPER_MAGIC:
 101       fsname = "ntfs";
 102       break;
 103     case LOGFS_MAGIC_U32:
 104       fsname = "logfs";
 105       break;
 106     }
 107
 108   FILE *mtab = __setmntent ("/proc/mounts", "r");
 109   if (mtab == NULL)
 110     mtab = __setmntent (_PATH_MOUNTED, "r");
 111
 112   int result = 0;
 113   if (mtab != NULL)
 114     {
 115       bool success = false;
 116       struct mntent mntbuf;
 117       char tmpbuf[1024];
 118
 119       /* No locking needed.  */
 120       (void) __fsetlocking (mtab, FSETLOCKING_BYCALLER);
 121
 122     again:
 123       while (__getmntent_r (mtab, &mntbuf, tmpbuf, sizeof (tmpbuf)))
 124         {
 125           /* In a first round we look for a given mount point, if
 126              we have a name.  */
 127           if (name != NULL && strcmp (name, mntbuf.mnt_dir) != 0)
 128             continue;
 129           /* We need to look at the entry only if the filesystem
 130              name matches.  If we have a filesystem name.  */
 131           else if (fsname != NULL
 132                    && strcmp (fsname, mntbuf.mnt_type) != 0
 133                    && (fsname2 == NULL
 134                        || strcmp (fsname2, mntbuf.mnt_type) != 0)
 135                    && (fsname3 == NULL
 136                        || strcmp (fsname3, mntbuf.mnt_type) != 0))
 137             continue;
 138
 139           /* Find out about the device the current entry is for.  */
 140           struct stat64 fsst;
 141           if (stat64 (mntbuf.mnt_dir, &fsst) >= 0
 142               && st->st_dev == fsst.st_dev)
 143             {
 144               /* Bingo, we found the entry for the device FD is on.
 145                  Now interpret the option string.  */
 146               char *cp = mntbuf.mnt_opts;
 147               char *opt;
 148
 149               while ((opt = strsep (&cp, ",")) != NULL)
 150                 if (strcmp (opt, "ro") == 0)
 151                   result |= ST_RDONLY;
 152                 else if (strcmp (opt, "nosuid") == 0)
 153                   result |= ST_NOSUID;
 154                 else if (strcmp (opt, "noexec") == 0)
 155                   result |= ST_NOEXEC;
 156                 else if (strcmp (opt, "nodev") == 0)
 157                   result |= ST_NODEV;
 158                 else if (strcmp (opt, "sync") == 0)
 159                   result |= ST_SYNCHRONOUS;
 160                 else if (strcmp (opt, "mand") == 0)
 161                   result |= ST_MANDLOCK;
 162                 else if (strcmp (opt, "noatime") == 0)
 163                   result |= ST_NOATIME;
 164                 else if (strcmp (opt, "nodiratime") == 0)
 165                   result |= ST_NODIRATIME;
 166                 else if (strcmp (opt, "relatime") == 0)
 167                   result |= ST_RELATIME;
 168
 169               /* We can stop looking for more entries.  */
 170               success = true;
 171               break;
 172             }
 173         }
 174       /* Maybe the kernel names for the filesystems changed or the
 175          statvfs call got a name which was not the mount point.  Check
 176          again, this time without checking for name matches first.  */
 177       if (! success && (name != NULL || fsname != NULL))
 178         {
 179           if (name != NULL)
 180             /* Try without a mount point name.  */
 181             name = NULL;
 182           else
 183             {
 184               /* Try without a filesystem name.  */
 185               assert (fsname != NULL);
 186               fsname = fsname2 = fsname3 = NULL;
 187             }
 188
 189           /* It is not strictly allowed to use rewind here.  But
 190              this code is part of the implementation so it is
 191              acceptable.  */
 192           rewind (mtab);
 193
 194           goto again;
 195         }
 196
 197       /* Close the file.  */
 198       __endmntent (mtab);
 199     }
 200
 201   return result;
 202 }
 203 #else
 204 extern int __statvfs_getflags (const char *name, int fstype,
 205                                struct stat64 *st);
 206 #endif
 207
 208
 209 void
 210 INTERNAL_STATVFS (const char *name, struct STATVFS *buf,
 211                   struct STATFS *fsbuf, struct stat64 *st)
 212 {
 213   /* Now fill in the fields we have information for.  */
 214   buf->f_bsize = fsbuf->f_bsize;
 215   /* Linux has the f_frsize size only in later version of the kernel.
 216      If the value is not filled in use f_bsize.  */
 217   buf->f_frsize = fsbuf->f_frsize ?: fsbuf->f_bsize;
 218   buf->f_blocks = fsbuf->f_blocks;
 219   buf->f_bfree = fsbuf->f_bfree;
 220   buf->f_bavail = fsbuf->f_bavail;
 221   buf->f_files = fsbuf->f_files;
 222   buf->f_ffree = fsbuf->f_ffree;
 223   if (sizeof (buf->f_fsid) == sizeof (fsbuf->f_fsid))
 224     buf->f_fsid = (fsbuf->f_fsid.__val[0]
 225                    | ((unsigned long int) fsbuf->f_fsid.__val[1]
 226                       << (8 * (sizeof (buf->f_fsid)
 227                                - sizeof (fsbuf->f_fsid.__val[0])))));
 228   else
 229     /* We cannot help here.  The statvfs element is not large enough to
 230        contain both words of the statfs f_fsid field.  */
 231     buf->f_fsid = fsbuf->f_fsid.__val[0];
 232 #ifdef _STATVFSBUF_F_UNUSED
 233   buf->__f_unused = 0;
 234 #endif
 235   buf->f_namemax = fsbuf->f_namelen;
 236   memset (buf->__f_spare, '\0', sizeof (buf->__f_spare));
 237
 238   /* What remains to do is to fill the fields f_favail and f_flag.  */
 239
 240   /* XXX I have no idea how to compute f_favail.  Any idea???  */
 241   buf->f_favail = buf->f_ffree;
 242
 243   /* Determining the flags is tricky.  We have to read /proc/mounts or
 244      the /etc/mtab file and search for the entry which matches the given
 245      file.  The way we can test for matching filesystem is using the
 246      device number.  */
 247   buf->f_flag = __statvfs_getflags (name, fsbuf->f_type, st);
 248 }