sysdeps/unix/sysv/linux/internal_statvfs.c

   1 /* Copyright (C) 1998-2003, 2004 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
  49   /* Map the filesystem type we got from the statfs call to a string.  */
  50   switch (fstype)
  51     {
  52     case EXT2_SUPER_MAGIC:
  53       fsname = "ext3";
  54       fsname2 = "ext2";
  55       break;
  56     case DEVPTS_SUPER_MAGIC:
  57       fsname= "devpts";
  58       break;
  59     case SHMFS_SUPER_MAGIC:
  60       fsname = "tmpfs";
  61       break;
  62     case PROC_SUPER_MAGIC:
  63       fsname = "proc";
  64       break;
  65     case USBDEVFS_SUPER_MAGIC:
  66       fsname = "usbdevfs";
  67       break;
  68     case AUTOFS_SUPER_MAGIC:
  69       fsname = "autofs";
  70       break;
  71     case NFS_SUPER_MAGIC:
  72       fsname = "nfs";
  73       break;
  74     }
  75
  76   FILE *mtab = __setmntent ("/proc/mounts", "r");
  77   if (mtab == NULL)
  78     mtab = __setmntent (_PATH_MOUNTED, "r");
  79
  80   int result = 0;
  81   if (mtab != NULL)
  82     {
  83       bool success = false;
  84       struct mntent mntbuf;
  85       char tmpbuf[1024];
  86
  87       /* No locking needed.  */
  88       (void) __fsetlocking (mtab, FSETLOCKING_BYCALLER);
  89
  90     again:
  91       while (__getmntent_r (mtab, &mntbuf, tmpbuf, sizeof (tmpbuf)))
  92         {
  93           /* In a first round we look for a given mount point, if
  94              we have a name.  */
  95           if (name != NULL && strcmp (name, mntbuf.mnt_dir) != 0)
  96             continue;
  97           /* We need to look at the entry only if the filesystem
  98              name matches.  If we have a filesystem name.  */
  99           else if (fsname != NULL
 100                    && strcmp (fsname, mntbuf.mnt_type) != 0
 101                    && (fsname2 == NULL
 102                        || strcmp (fsname2, mntbuf.mnt_type) != 0))
 103             continue;
 104
 105           /* Find out about the device the current entry is for.  */
 106           struct stat64 fsst;
 107           if (stat64 (mntbuf.mnt_dir, &fsst) >= 0
 108               && st->st_dev == fsst.st_dev)
 109             {
 110               /* Bingo, we found the entry for the device FD is on.
 111                  Now interpret the option string.  */
 112               char *cp = mntbuf.mnt_opts;
 113               char *opt;
 114
 115               while ((opt = strsep (&cp, ",")) != NULL)
 116                 if (strcmp (opt, "ro") == 0)
 117                   result |= ST_RDONLY;
 118                 else if (strcmp (opt, "nosuid") == 0)
 119                   result |= ST_NOSUID;
 120                 else if (strcmp (opt, "noexec") == 0)
 121                   result |= ST_NOEXEC;
 122                 else if (strcmp (opt, "nodev") == 0)
 123                   result |= ST_NODEV;
 124                 else if (strcmp (opt, "sync") == 0)
 125                   result |= ST_SYNCHRONOUS;
 126                 else if (strcmp (opt, "mand") == 0)
 127                   result |= ST_MANDLOCK;
 128                 else if (strcmp (opt, "noatime") == 0)
 129                   result |= ST_NOATIME;
 130                 else if (strcmp (opt, "nodiratime") == 0)
 131                   result |= ST_NODIRATIME;
 132
 133               /* We can stop looking for more entries.  */
 134               success = true;
 135               break;
 136             }
 137         }
 138       /* Maybe the kernel names for the filesystems changed or the
 139          statvfs call got a name which was not the mount point.  Check
 140          again, this time without checking for name matches first.  */
 141       if (! success && (name != NULL || fsname != NULL))
 142         {
 143           if (name != NULL)
 144             /* Try without a mount point name.  */
 145             name = NULL;
 146           else
 147             {
 148               /* Try without a filesystem name.  */
 149               assert (fsname != NULL);
 150               fsname = fsname2 = NULL;
 151             }
 152
 153           /* It is not strictly allowed to use rewind here.  But
 154              this code is part of the implementation so it is
 155              acceptable.  */
 156           rewind (mtab);
 157
 158           goto again;
 159         }
 160
 161       /* Close the file.  */
 162       __endmntent (mtab);
 163     }
 164
 165   return result;
 166 }
 167 #else
 168 extern int __statvfs_getflags (const char *name, int fstype,
 169                                struct stat64 *st);
 170 #endif
 171
 172
 173 void
 174 INTERNAL_STATVFS (const char *name, struct STATVFS *buf,
 175                   struct STATFS *fsbuf, struct stat64 *st)
 176 {
 177   /* Now fill in the fields we have information for.  */
 178   buf->f_bsize = fsbuf->f_bsize;
 179   /* Linux has the f_frsize size only in later version of the kernel.
 180      If the value is not filled in use f_bsize.  */
 181   buf->f_frsize = fsbuf->f_frsize ?: fsbuf->f_bsize;
 182   buf->f_blocks = fsbuf->f_blocks;
 183   buf->f_bfree = fsbuf->f_bfree;
 184   buf->f_bavail = fsbuf->f_bavail;
 185   buf->f_files = fsbuf->f_files;
 186   buf->f_ffree = fsbuf->f_ffree;
 187   if (sizeof (buf->f_fsid) == sizeof (fsbuf->f_fsid))
 188     buf->f_fsid = (fsbuf->f_fsid.__val[0]
 189                    | ((unsigned long int) fsbuf->f_fsid.__val[1]
 190                       << (8 * (sizeof (buf->f_fsid)
 191                                - sizeof (fsbuf->f_fsid.__val[0])))));
 192   else
 193     /* We cannot help here.  The statvfs element is not large enough to
 194        contain both words of the statfs f_fsid field.  */
 195     buf->f_fsid = fsbuf->f_fsid.__val[0];
 196 #ifdef _STATVFSBUF_F_UNUSED
 197   buf->__f_unused = 0;
 198 #endif
 199   buf->f_namemax = fsbuf->f_namelen;
 200   memset (buf->__f_spare, '\0', sizeof (buf->__f_spare));
 201
 202   /* What remains to do is to fill the fields f_favail and f_flag.  */
 203
 204   /* XXX I have no idea how to compute f_favail.  Any idea???  */
 205   buf->f_favail = buf->f_ffree;
 206
 207   /* Determining the flags is tricky.  We have to read /proc/mounts or
 208      the /etc/mtab file and search for the entry which matches the given
 209      file.  The way we can test for matching filesystem is using the
 210      device number.  */
 211   buf->f_flag = __statvfs_getflags (name, fsbuf->f_type, st);
 212 }