misc/fstab.c

   1 /* Copyright (C) 1995-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <fstab.h>
  19 #include <mntent.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <bits/libc-lock.h>
  24
  25 #define BUFFER_SIZE 0x1fc0
  26
  27 struct fstab_state
  28 {
  29   FILE *fs_fp;
  30   char *fs_buffer;
  31   struct mntent fs_mntres;
  32   struct fstab fs_ret;
  33 };
  34
  35 static struct fstab_state *fstab_init (int opt_rewind);
  36 static struct mntent *fstab_fetch (struct fstab_state *state);
  37 static struct fstab *fstab_convert (struct fstab_state *state);
  38
  39 static struct fstab_state fstab_state;
  40
  41
  42 int
  43 setfsent (void)
  44 {
  45   return fstab_init (1) != NULL;
  46 }
  47
  48
  49 struct fstab *
  50 getfsent (void)
  51 {
  52   struct fstab_state *state;
  53
  54   state = fstab_init (0);
  55   if (state == NULL)
  56     return NULL;
  57   if (fstab_fetch (state) == NULL)
  58     return NULL;
  59   return fstab_convert (state);
  60 }
  61
  62
  63 struct fstab *
  64 getfsspec (name)
  65      const char *name;
  66 {
  67   struct fstab_state *state;
  68   struct mntent *m;
  69
  70   state = fstab_init (1);
  71   if (state == NULL)
  72     return NULL;
  73   while ((m = fstab_fetch (state)) != NULL)
  74     if (strcmp (m->mnt_fsname, name) == 0)
  75       return fstab_convert (state);
  76   return NULL;
  77 }
  78
  79
  80 struct fstab *
  81 getfsfile (name)
  82      const char *name;
  83 {
  84   struct fstab_state *state;
  85   struct mntent *m;
  86
  87   state = fstab_init (1);
  88   if (state == NULL)
  89     return NULL;
  90   while ((m = fstab_fetch (state)) != NULL)
  91     if (strcmp (m->mnt_dir, name) == 0)
  92       return fstab_convert (state);
  93   return NULL;
  94 }
  95
  96
  97 void
  98 endfsent (void)
  99 {
 100   struct fstab_state *state;
 101
 102   state = &fstab_state;
 103   if (state->fs_fp != NULL)
 104     {
 105       (void) __endmntent (state->fs_fp);
 106       state->fs_fp = NULL;
 107     }
 108 }
 109
 110
 111 static struct fstab_state *
 112 fstab_init (int opt_rewind)
 113 {
 114   struct fstab_state *state;
 115   char *buffer;
 116   FILE *fp;
 117
 118   state = &fstab_state;
 119
 120   buffer = state->fs_buffer;
 121   if (buffer == NULL)
 122     {
 123       buffer = (char *) malloc (BUFFER_SIZE);
 124       if (buffer == NULL)
 125         return NULL;
 126       state->fs_buffer = buffer;
 127     }
 128
 129   fp = state->fs_fp;
 130   if (fp != NULL)
 131     {
 132       if (opt_rewind)
 133         rewind (fp);
 134     }
 135   else
 136     {
 137       fp = __setmntent (_PATH_FSTAB, "r");
 138       if (fp == NULL)
 139         return NULL;
 140       state->fs_fp = fp;
 141     }
 142
 143   return state;
 144 }
 145
 146
 147 static struct mntent *
 148 fstab_fetch (struct fstab_state *state)
 149 {
 150   return __getmntent_r (state->fs_fp, &state->fs_mntres,
 151                         state->fs_buffer, BUFFER_SIZE);
 152 }
 153
 154
 155 static struct fstab *
 156 fstab_convert (struct fstab_state *state)
 157 {
 158   struct mntent *m;
 159   struct fstab *f;
 160
 161   m = &state->fs_mntres;
 162   f = &state->fs_ret;
 163
 164   f->fs_spec = m->mnt_fsname;
 165   f->fs_file = m->mnt_dir;
 166   f->fs_vfstype = m->mnt_type;
 167   f->fs_mntops = m->mnt_opts;
 168   f->fs_type = (__hasmntopt (m, FSTAB_RW) ? FSTAB_RW :
 169                 __hasmntopt (m, FSTAB_RQ) ? FSTAB_RQ :
 170                 __hasmntopt (m, FSTAB_RO) ? FSTAB_RO :
 171                 __hasmntopt (m, FSTAB_SW) ? FSTAB_SW :
 172                 __hasmntopt (m, FSTAB_XX) ? FSTAB_XX :
 173                 "??");
 174   f->fs_freq = m->mnt_freq;
 175   f->fs_passno = m->mnt_passno;
 176   return f;
 177 }
 178
 179
 180 /* Make sure the memory is freed if the programs ends while in
 181    memory-debugging mode and something actually was allocated.  */
 182 libc_freeres_fn (fstab_free)
 183 {
 184   char *buffer;
 185
 186   buffer = fstab_state.fs_buffer;
 187   free ((void *) buffer);
 188 }