misc/mntent_r.c

   1 /* Utilities for reading/writing fstab, mtab, etc.
   2    Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <mntent.h>
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <sys/types.h>
  24
  25 #ifdef USE_IN_LIBIO
  26 # define flockfile(s) _IO_flockfile (s)
  27 # define funlockfile(s) _IO_funlockfile (s)
  28 #endif
  29
  30 /* Prepare to begin reading and/or writing mount table entries from the
  31    beginning of FILE.  MODE is as for `fopen'.  */
  32 FILE *
  33 __setmntent (const char *file, const char *mode)
  34 {
  35   return fopen (file, mode);
  36 }
  37 weak_alias (__setmntent, setmntent)
  38
  39
  40 /* Close a stream opened with `setmntent'.  */
  41 int
  42 __endmntent (FILE *stream)
  43 {
  44   if (stream)           /* SunOS 4.x allows for NULL stream */
  45     fclose (stream);
  46   return 1;             /* SunOS 4.x says to always return 1 */
  47 }
  48 weak_alias (__endmntent, endmntent)
  49
  50
  51 /* Read one mount table entry from STREAM.  Returns a pointer to storage
  52    reused on the next call, or null for EOF or error (use feof/ferror to
  53    check).  */
  54 struct mntent *
  55 __getmntent_r (FILE *stream, struct mntent *mp, char *buffer, int bufsiz)
  56 {
  57   char *head;
  58
  59   flockfile (stream);
  60   do
  61     {
  62       char *end_ptr;
  63
  64       if (fgets_unlocked (buffer, bufsiz, stream) == NULL)
  65         {
  66           funlockfile (stream);
  67           return NULL;
  68         }
  69
  70       end_ptr = strchr (buffer, '\n');
  71       if (end_ptr != NULL)      /* chop newline */
  72         *end_ptr = '\0';
  73       else
  74         {
  75           /* Not the whole line was read.  Do it now but forget it.  */
  76           char tmp[1024];
  77           while (fgets_unlocked (tmp, sizeof tmp, stream) != NULL)
  78             if (strchr (tmp, '\n') != NULL)
  79               break;
  80         }
  81
  82       head = buffer + strspn (buffer, " \t");
  83       /* skip empty lines and comment lines:  */
  84     } while (head[0] == '\0' || head[0] == '#');
  85
  86   mp->mnt_fsname = __strsep (&head, " \t") ?: (char *) "";
  87   if (head)
  88     head += strspn (head, " \t");
  89   mp->mnt_dir = __strsep (&head, " \t") ?: (char *) "";
  90   if (head)
  91     head += strspn (head, " \t");
  92   mp->mnt_type = __strsep (&head, " \t") ?: (char *) "";
  93   if (head)
  94     head += strspn (head, " \t");
  95   mp->mnt_opts = __strsep (&head, " \t") ?: (char *) "";
  96   switch (head ? sscanf (head, " %d %d ", &mp->mnt_freq, &mp->mnt_passno) : 0)
  97     {
  98     case 0:
  99       mp->mnt_freq = 0;
 100     case 1:
 101       mp->mnt_passno = 0;
 102     case 2:
 103     }
 104   funlockfile (stream);
 105
 106   return mp;
 107 }
 108 weak_alias (__getmntent_r, getmntent_r)
 109
 110 /* Write the mount table entry described by MNT to STREAM.
 111    Return zero on success, nonzero on failure.  */
 112 int
 113 __addmntent (FILE *stream, const struct mntent *mnt)
 114 {
 115   if (fseek (stream, 0, SEEK_END))
 116     return 1;
 117
 118   return (fprintf (stream, "%s %s %s %s %d %d\n",
 119                    mnt->mnt_fsname,
 120                    mnt->mnt_dir,
 121                    mnt->mnt_type,
 122                    mnt->mnt_opts,
 123                    mnt->mnt_freq,
 124                    mnt->mnt_passno)
 125           < 0 ? 1 : 0);
 126 }
 127 weak_alias (__addmntent, addmntent)
 128
 129
 130 /* Search MNT->mnt_opts for an option matching OPT.
 131    Returns the address of the substring, or null if none found.  */
 132 char *
 133 __hasmntopt (const struct mntent *mnt, const char *opt)
 134 {
 135   const size_t optlen = strlen (opt);
 136   char *rest = mnt->mnt_opts, *p;
 137
 138   while ((p = strstr (rest, opt)) != NULL)
 139     {
 140       if (p == rest
 141           || (p[-1] == ','
 142               && (p[optlen] == '\0' ||
 143                   p[optlen] == '='  ||
 144                   p[optlen] == ',')))
 145         return p;
 146
 147       rest = strchr (rest, ',');
 148       if (rest == NULL)
 149         break;
 150       ++rest;
 151     }
 152
 153   return NULL;
 154 }
 155 weak_alias (__hasmntopt, hasmntopt)