grp/grpread.c

   1 /* Copyright (C) 1991, 1992, 1995 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <stddef.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/types.h>
  26 #include <grp.h>
  27
  28 /* This is the function that all the others are based on.
  29    The format of the group file is known only here.  */
  30
  31 /* Structure containing info kept by each __grpread caller.  */
  32 typedef struct
  33   {
  34     char *buf;
  35     size_t buflen;
  36     size_t max_members;
  37     char **members;
  38     struct group g;
  39   } grpread_info;
  40
  41
  42 /* Return a chunk of memory containing a pre-initialized `grpread_info'.  */
  43 PTR
  44 DEFUN_VOID(__grpalloc)
  45 {
  46   grpread_info *info = (PTR) malloc (sizeof(grpread_info));
  47   if (info == NULL)
  48     return NULL;
  49
  50   info->buf = NULL;
  51   info->buflen = 0;
  52
  53   info->max_members = 5;
  54   info->members = (char **) malloc (5 * sizeof(char *));
  55   if (info->members == NULL)
  56     {
  57       free ((PTR) info);
  58       return NULL;
  59     }
  60
  61   return info;
  62 }
  63
  64 /* Read a group entry from STREAM, filling in G.  */
  65 struct group *
  66 DEFUN(__grpread, (stream, g), FILE *stream AND PTR CONST g)
  67 {
  68   register grpread_info *CONST info = (grpread_info *) g;
  69   char *start, *end;
  70   register size_t i;
  71
  72   /* Idiocy checks.  */
  73   if (stream == NULL)
  74     {
  75       errno = EINVAL;
  76       return NULL;
  77     }
  78
  79   do
  80     if (__getline (&info->buf, &info->buflen, stream) == -1)
  81       return NULL;
  82   while (info->buf[0] == '#');
  83
  84   start = info->buf;
  85   end = strchr (start, ':');
  86   if (end == NULL)
  87     return NULL;
  88   *end = '\0';
  89   info->g.gr_name = start;
  90
  91   start = end + 1;
  92   end = strchr (start, ':');
  93   if (end == NULL)
  94     return NULL;
  95   *end = '\0';
  96   info->g.gr_passwd = start;
  97
  98   info->g.gr_gid = (gid_t) strtol (end + 1, &end, 10);
  99   if (*end != ':')
 100     return NULL;
 101
 102   i = 0;
 103   do
 104     {
 105       start = end + 1;
 106       end = strchr (start, ',');
 107       if (end == NULL)
 108         {
 109           end = strchr (start, '\n');
 110           if (end == start)
 111             break;
 112           if (end == NULL)
 113             return NULL;
 114           *end = '\0';
 115           end = NULL;
 116         }
 117       else
 118         *end = '\0';
 119
 120       if (i == info->max_members - 2)
 121         {
 122           info->max_members += 5;
 123           info->members = (char **)
 124             realloc ((PTR) info->members, info->max_members * sizeof (char *));
 125           if (info->members == NULL)
 126             return NULL;
 127         }
 128
 129       info->members[i++] = start;
 130     } while (end != NULL);
 131   info->members[i] = NULL;
 132   info->g.gr_mem = info->members;
 133
 134   return &info->g;
 135 }
 136
 137
 138 struct group *
 139 __grpscan (void **info, int (*selector) (struct group *))
 140 {
 141   FILE *stream;
 142   struct group *p;
 143
 144   if (*info == NULL)
 145     {
 146       *info = __grpalloc ();
 147       if (info == NULL)
 148         return NULL;
 149     }
 150
 151   stream = __grpopen ();
 152   if (stream == NULL)
 153     return NULL;
 154
 155   p = NULL;
 156   while (! feof (stream))
 157     {
 158       p = __grpread (stream, *info);
 159       if (p && (*selector) (p))
 160         break;
 161       p = NULL;
 162     }
 163
 164   (void) fclose (stream);
 165   return p;
 166 }