misc/fstab.c

   1 /* Copyright (C) 1995-2020 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    <https://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 <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 (const char *name)
  65 {
  66   struct fstab_state *state;
  67   struct mntent *m;
  68
  69   state = fstab_init (1);
  70   if (state == NULL)
  71     return NULL;
  72   while ((m = fstab_fetch (state)) != NULL)
  73     if (strcmp (m->mnt_fsname, name) == 0)
  74       return fstab_convert (state);
  75   return NULL;
  76 }
  77
  78
  79 struct fstab *
  80 getfsfile (const char *name)
  81 {
  82   struct fstab_state *state;
  83   struct mntent *m;
  84
  85   state = fstab_init (1);
  86   if (state == NULL)
  87     return NULL;
  88   while ((m = fstab_fetch (state)) != NULL)
  89     if (strcmp (m->mnt_dir, name) == 0)
  90       return fstab_convert (state);
  91   return NULL;
  92 }
  93
  94
  95 void
  96 endfsent (void)
  97 {
  98   struct fstab_state *state;
  99
 100   state = &fstab_state;
 101   if (state->fs_fp != NULL)
 102     {
 103       (void) __endmntent (state->fs_fp);
 104       state->fs_fp = NULL;
 105     }
 106 }
 107
 108
 109 static struct fstab_state *
 110 fstab_init (int opt_rewind)
 111 {
 112   struct fstab_state *state;
 113   char *buffer;
 114   FILE *fp;
 115
 116   state = &fstab_state;
 117
 118   buffer = state->fs_buffer;
 119   if (buffer == NULL)
 120     {
 121       buffer = (char *) malloc (BUFFER_SIZE);
 122       if (buffer == NULL)
 123         return NULL;
 124       state->fs_buffer = buffer;
 125     }
 126
 127   fp = state->fs_fp;
 128   if (fp != NULL)
 129     {
 130       if (opt_rewind)
 131         rewind (fp);
 132     }
 133   else
 134     {
 135       fp = __setmntent (_PATH_FSTAB, "r");
 136       if (fp == NULL)
 137         return NULL;
 138       state->fs_fp = fp;
 139     }
 140
 141   return state;
 142 }
 143
 144
 145 static struct mntent *
 146 fstab_fetch (struct fstab_state *state)
 147 {
 148   return __getmntent_r (state->fs_fp, &state->fs_mntres,
 149                         state->fs_buffer, BUFFER_SIZE);
 150 }
 151
 152
 153 static struct fstab *
 154 fstab_convert (struct fstab_state *state)
 155 {
 156   struct mntent *m;
 157   struct fstab *f;
 158
 159   m = &state->fs_mntres;
 160   f = &state->fs_ret;
 161
 162   f->fs_spec = m->mnt_fsname;
 163   f->fs_file = m->mnt_dir;
 164   f->fs_vfstype = m->mnt_type;
 165   f->fs_mntops = m->mnt_opts;
 166   f->fs_type = (__hasmntopt (m, FSTAB_RW) ? FSTAB_RW
 167                 : __hasmntopt (m, FSTAB_RQ) ? FSTAB_RQ
 168                 : __hasmntopt (m, FSTAB_RO) ? FSTAB_RO
 169                 : __hasmntopt (m, FSTAB_SW) ? FSTAB_SW
 170                 : __hasmntopt (m, FSTAB_XX) ? FSTAB_XX
 171                 : "??");
 172   f->fs_freq = m->mnt_freq;
 173   f->fs_passno = m->mnt_passno;
 174   return f;
 175 }
 176
 177
 178 /* Make sure the memory is freed if the programs ends while in
 179    memory-debugging mode and something actually was allocated.  */
 180 libc_freeres_fn (fstab_free)
 181 {
 182   char *buffer;
 183
 184   buffer = fstab_state.fs_buffer;
 185   free ((void *) buffer);
 186 }