sysdeps/unix/sysv/linux/internal_statvfs.c

   1 /* Copyright (C) 1998-2003, 2004, 2005, 2006 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     case SYSFS_MAGIC:
  75       fsname = "sysfs";
  76       break;
  77     case REISERFS_SUPER_MAGIC:
  78       fsname = "reiserfs";
  79       break;
  80     case XFS_SUPER_MAGIC:
  81       fsname = "xfs";
  82       break;
  83     case JFS_SUPER_MAGIC:
  84       fsname = "jfs";
  85       break;
  86     case HPFS_SUPER_MAGIC:
  87       fsname = "hpfs";
  88       break;
  89     case DEVFS_SUPER_MAGIC:
  90       fsname = "devfs";
  91       break;
  92     case ISOFS_SUPER_MAGIC:
  93       fsname = "iso9660";
  94       break;
  95     case MSDOS_SUPER_MAGIC:
  96       fsname = "msdos";
  97       break;
  98     case NTFS_SUPER_MAGIC:
  99       fsname = "ntfs";
 100       break;
 101     }
 102
 103   FILE *mtab = __setmntent ("/proc/mounts", "r");
 104   if (mtab == NULL)
 105     mtab = __setmntent (_PATH_MOUNTED, "r");
 106
 107   int result = 0;
 108   if (mtab != NULL)
 109     {
 110       bool success = false;
 111       struct mntent mntbuf;
 112       char tmpbuf[1024];
 113
 114       /* No locking needed.  */
 115       (void) __fsetlocking (mtab, FSETLOCKING_BYCALLER);
 116
 117     again:
 118       while (__getmntent_r (mtab, &mntbuf, tmpbuf, sizeof (tmpbuf)))
 119         {
 120           /* In a first round we look for a given mount point, if
 121              we have a name.  */
 122           if (name != NULL && strcmp (name, mntbuf.mnt_dir) != 0)
 123             continue;
 124           /* We need to look at the entry only if the filesystem
 125              name matches.  If we have a filesystem name.  */
 126           else if (fsname != NULL
 127                    && strcmp (fsname, mntbuf.mnt_type) != 0
 128                    && (fsname2 == NULL
 129                        || strcmp (fsname2, mntbuf.mnt_type) != 0))
 130             continue;
 131
 132           /* Find out about the device the current entry is for.  */
 133           struct stat64 fsst;
 134           if (stat64 (mntbuf.mnt_dir, &fsst) >= 0
 135               && st->st_dev == fsst.st_dev)
 136             {
 137               /* Bingo, we found the entry for the device FD is on.
 138                  Now interpret the option string.  */
 139               char *cp = mntbuf.mnt_opts;
 140               char *opt;
 141
 142               while ((opt = strsep (&cp, ",")) != NULL)
 143                 if (strcmp (opt, "ro") == 0)
 144                   result |= ST_RDONLY;
 145                 else if (strcmp (opt, "nosuid") == 0)
 146                   result |= ST_NOSUID;
 147                 else if (strcmp (opt, "noexec") == 0)
 148                   result |= ST_NOEXEC;
 149                 else if (strcmp (opt, "nodev") == 0)
 150                   result |= ST_NODEV;
 151                 else if (strcmp (opt, "sync") == 0)
 152                   result |= ST_SYNCHRONOUS;
 153                 else if (strcmp (opt, "mand") == 0)
 154                   result |= ST_MANDLOCK;
 155                 else if (strcmp (opt, "noatime") == 0)
 156                   result |= ST_NOATIME;
 157                 else if (strcmp (opt, "nodiratime") == 0)
 158                   result |= ST_NODIRATIME;
 159                 else if (strcmp (opt, "relatime") == 0)
 160                   result |= ST_RELATIME;
 161
 162               /* We can stop looking for more entries.  */
 163               success = true;
 164               break;
 165             }
 166         }
 167       /* Maybe the kernel names for the filesystems changed or the
 168          statvfs call got a name which was not the mount point.  Check
 169          again, this time without checking for name matches first.  */
 170       if (! success && (name != NULL || fsname != NULL))
 171         {
 172           if (name != NULL)
 173             /* Try without a mount point name.  */
 174             name = NULL;
 175           else
 176             {
 177               /* Try without a filesystem name.  */
 178               assert (fsname != NULL);
 179               fsname = fsname2 = NULL;
 180             }
 181
 182           /* It is not strictly allowed to use rewind here.  But
 183              this code is part of the implementation so it is
 184              acceptable.  */
 185           rewind (mtab);
 186
 187           goto again;
 188         }
 189
 190       /* Close the file.  */
 191       __endmntent (mtab);
 192     }
 193
 194   return result;
 195 }
 196 #else
 197 extern int __statvfs_getflags (const char *name, int fstype,
 198                                struct stat64 *st);
 199 #endif
 200
 201
 202 void
 203 INTERNAL_STATVFS (const char *name, struct STATVFS *buf,
 204                   struct STATFS *fsbuf, struct stat64 *st)
 205 {
 206   /* Now fill in the fields we have information for.  */
 207   buf->f_bsize = fsbuf->f_bsize;
 208   /* Linux has the f_frsize size only in later version of the kernel.
 209      If the value is not filled in use f_bsize.  */
 210   buf->f_frsize = fsbuf->f_frsize ?: fsbuf->f_bsize;
 211   buf->f_blocks = fsbuf->f_blocks;
 212   buf->f_bfree = fsbuf->f_bfree;
 213   buf->f_bavail = fsbuf->f_bavail;
 214   buf->f_files = fsbuf->f_files;
 215   buf->f_ffree = fsbuf->f_ffree;
 216   if (sizeof (buf->f_fsid) == sizeof (fsbuf->f_fsid))
 217     buf->f_fsid = (fsbuf->f_fsid.__val[0]
 218                    | ((unsigned long int) fsbuf->f_fsid.__val[1]
 219                       << (8 * (sizeof (buf->f_fsid)
 220                                - sizeof (fsbuf->f_fsid.__val[0])))));
 221   else
 222     /* We cannot help here.  The statvfs element is not large enough to
 223        contain both words of the statfs f_fsid field.  */
 224     buf->f_fsid = fsbuf->f_fsid.__val[0];
 225 #ifdef _STATVFSBUF_F_UNUSED
 226   buf->__f_unused = 0;
 227 #endif
 228   buf->f_namemax = fsbuf->f_namelen;
 229   memset (buf->__f_spare, '\0', sizeof (buf->__f_spare));
 230
 231   /* What remains to do is to fill the fields f_favail and f_flag.  */
 232
 233   /* XXX I have no idea how to compute f_favail.  Any idea???  */
 234   buf->f_favail = buf->f_ffree;
 235
 236   /* Determining the flags is tricky.  We have to read /proc/mounts or
 237      the /etc/mtab file and search for the entry which matches the given
 238      file.  The way we can test for matching filesystem is using the
 239      device number.  */
 240   buf->f_flag = __statvfs_getflags (name, fsbuf->f_type, st);
 241 }