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 /* Prepare to begin reading and/or writing mount table entries from the
  26    beginning of FILE.  MODE is as for `fopen'.  */
  27 FILE *
  28 __setmntent (const char *file, const char *mode)
  29 {
  30   return fopen (file, mode);
  31 }
  32 weak_alias (__setmntent, setmntent)
  33
  34
  35 /* Close a stream opened with `setmntent'.  */
  36 int
  37 __endmntent (FILE *stream)
  38 {
  39   if (stream)           /* SunOS 4.x allows for NULL stream */
  40     fclose (stream);
  41   return 1;             /* SunOS 4.x says to always return 1 */
  42 }
  43 weak_alias (__endmntent, endmntent)
  44
  45
  46 /* Read one mount table entry from STREAM.  Returns a pointer to storage
  47    reused on the next call, or null for EOF or error (use feof/ferror to
  48    check).  */
  49 struct mntent *
  50 __getmntent_r (FILE *stream, struct mntent *mp, char *buffer, int bufsiz)
  51 {
  52   char *head;
  53
  54   flockfile (stream);
  55   do
  56     {
  57       char *end_ptr;
  58
  59       if (fgets_unlocked (buffer, bufsiz, stream) == NULL)
  60         {
  61           funlockfile (stream);
  62           return NULL;
  63         }
  64
  65       end_ptr = strchr (buffer, '\n');
  66       if (end_ptr != NULL)      /* chop newline */
  67         *end_ptr = '\0';
  68       else
  69         {
  70           /* Not the whole line was read.  Do it now but forget it.  */
  71           char tmp[1024];
  72           while (fgets_unlocked (tmp, sizeof tmp, stream) != NULL)
  73             if (strchr (tmp, '\n') != NULL)
  74               break;
  75         }
  76
  77       head = buffer + strspn (buffer, " \t");
  78       /* skip empty lines and comment lines:  */
  79     } while (head[0] == '\0' || head[0] == '#');
  80
  81   mp->mnt_fsname = __strsep (&head, " \t") ?: (char *) "";
  82   if (head)
  83     head += strspn (head, " \t");
  84   mp->mnt_dir = __strsep (&head, " \t") ?: (char *) "";
  85   if (head)
  86     head += strspn (head, " \t");
  87   mp->mnt_type = __strsep (&head, " \t") ?: (char *) "";
  88   if (head)
  89     head += strspn (head, " \t");
  90   mp->mnt_opts = __strsep (&head, " \t") ?: (char *) "";
  91   switch (head ? sscanf (head, " %d %d ", &mp->mnt_freq, &mp->mnt_passno) : 0)
  92     {
  93     case 0:
  94       mp->mnt_freq = 0;
  95     case 1:
  96       mp->mnt_passno = 0;
  97     case 2:
  98     }
  99   funlockfile (stream);
 100
 101   return mp;
 102 }
 103 weak_alias (__getmntent_r, getmntent_r)
 104
 105 /* Write the mount table entry described by MNT to STREAM.
 106    Return zero on success, nonzero on failure.  */
 107 int
 108 __addmntent (FILE *stream, const struct mntent *mnt)
 109 {
 110   if (fseek (stream, 0, SEEK_END))
 111     return 1;
 112
 113   return (fprintf (stream, "%s %s %s %s %d %d\n",
 114                    mnt->mnt_fsname,
 115                    mnt->mnt_dir,
 116                    mnt->mnt_type,
 117                    mnt->mnt_opts,
 118                    mnt->mnt_freq,
 119                    mnt->mnt_passno)
 120           < 0 ? 1 : 0);
 121 }
 122 weak_alias (__addmntent, addmntent)
 123
 124
 125 /* Search MNT->mnt_opts for an option matching OPT.
 126    Returns the address of the substring, or null if none found.  */
 127 char *
 128 __hasmntopt (const struct mntent *mnt, const char *opt)
 129 {
 130   const size_t optlen = strlen (opt);
 131   char *rest = mnt->mnt_opts, *p;
 132
 133   while ((p = strstr (rest, opt)) != NULL)
 134     {
 135       if (p == rest || p[-1] == ',' &&
 136           (p[optlen] == '\0' ||
 137            p[optlen] == '=' ||
 138            p[optlen] == ','))
 139         return p;
 140
 141       rest = strchr (rest, ',');
 142       if (rest == NULL)
 143         break;
 144       ++rest;
 145     }
 146
 147   return NULL;
 148 }
 149 weak_alias (__hasmntopt, hasmntopt)