about summary refs log tree commit diff
path: root/sysdeps/unix/sysv/linux/internal_statvfs.c
blob: 83ffb99c0530886e3df7520cc2776209acd8e08f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
/* Copyright (C) 1998-2006, 2010 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <assert.h>
#include <errno.h>
#include <mntent.h>
#include <paths.h>
#include <stdbool.h>
#include <stdio_ext.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/statvfs.h>
#include "linux_fsinfo.h"
#include "kernel-features.h"


/* Special internal-only bit value.  */
#define ST_VALID 0x0020


#ifndef STATFS
# define STATFS statfs
# define STATVFS statvfs
# define INTERNAL_STATVFS __internal_statvfs


# ifndef __ASSUME_STATFS_F_FLAGS
int
__statvfs_getflags (const char *name, int fstype, struct stat64 *st)
{
  if (st == NULL)
    return 0;

  const char *fsname = NULL;
  const char *fsname2 = NULL;
  const char *fsname3 = NULL;

  /* Map the filesystem type we got from the statfs call to a string.  */
  switch (fstype)
    {
    case EXT2_SUPER_MAGIC:
      fsname = "ext4";
      fsname2 = "ext3";
      fsname3 = "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;
    case LOGFS_MAGIC_U32:
      fsname = "logfs";
      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)
		   && (fsname3 == NULL
		       || strcmp (fsname3, 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 = fsname3 = 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;
}
# endif
#else
extern int __statvfs_getflags (const char *name, int fstype,
			       struct stat64 *st);
#endif


void
INTERNAL_STATVFS (const char *name, struct STATVFS *buf,
		  struct STATFS *fsbuf, struct stat64 *st)
{
  /* Now fill in the fields we have information for.  */
  buf->f_bsize = fsbuf->f_bsize;
  /* Linux has the f_frsize size only in later version of the kernel.
     If the value is not filled in use f_bsize.  */
  buf->f_frsize = fsbuf->f_frsize ?: fsbuf->f_bsize;
  buf->f_blocks = fsbuf->f_blocks;
  buf->f_bfree = fsbuf->f_bfree;
  buf->f_bavail = fsbuf->f_bavail;
  buf->f_files = fsbuf->f_files;
  buf->f_ffree = fsbuf->f_ffree;
  if (sizeof (buf->f_fsid) == sizeof (fsbuf->f_fsid))
    buf->f_fsid = ((fsbuf->f_fsid.__val[0]
		    & ((1UL << (8 * sizeof (fsbuf->f_fsid.__val[0]))) - 1))
		   | ((unsigned long int) fsbuf->f_fsid.__val[1]
		      << (8 * (sizeof (buf->f_fsid)
			       - sizeof (fsbuf->f_fsid.__val[0])))));
  else
    /* We cannot help here.  The statvfs element is not large enough to
       contain both words of the statfs f_fsid field.  */
    buf->f_fsid = fsbuf->f_fsid.__val[0];
#ifdef _STATVFSBUF_F_UNUSED
  buf->__f_unused = 0;
#endif
  buf->f_namemax = fsbuf->f_namelen;
  memset (buf->__f_spare, '\0', sizeof (buf->__f_spare));

  /* What remains to do is to fill the fields f_favail and f_flag.  */

  /* XXX I have no idea how to compute f_favail.  Any idea???  */
  buf->f_favail = buf->f_ffree;

#ifndef __ASSUME_STATFS_F_FLAGS
  if ((fsbuf->f_flags & ST_VALID) == 0)
    /* Determining the flags is tricky.  We have to read /proc/mounts or
       the /etc/mtab file and search for the entry which matches the given
       file.  The way we can test for matching filesystem is using the
       device number.  */
    buf->f_flag = __statvfs_getflags (name, fsbuf->f_type, st);
  else
#endif
    buf->f_flag = fsbuf->f_flags ^ ST_VALID;
}