aboutsummaryrefslogtreecommitdiff
path: root/grp/grpread.c
blob: 1fed32f2e31095f302939623f3de45dd874bfc1e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
/* Copyright (C) 1991, 1992, 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <ansidecl.h>
#include <errno.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <grp.h>

/* This is the function that all the others are based on.
   The format of the group file is known only here.  */

/* Structure containing info kept by each __grpread caller.  */
typedef struct
  {
    char *buf;
    size_t buflen;
    size_t max_members;
    char **members;
    struct group g;
  } grpread_info;


/* Return a chunk of memory containing a pre-initialized `grpread_info'.  */
PTR
DEFUN_VOID(__grpalloc)
{
  grpread_info *info = (PTR) malloc (sizeof(grpread_info));
  if (info == NULL)
    return NULL;

  info->buf = NULL;
  info->buflen = 0;

  info->max_members = 5;
  info->members = (char **) malloc (5 * sizeof(char *));
  if (info->members == NULL)
    {
      free ((PTR) info);
      return NULL;
    }

  return info;
}

/* Read a group entry from STREAM, filling in G.  */
struct group *
DEFUN(__grpread, (stream, g), FILE *stream AND PTR CONST g)
{
  register grpread_info *CONST info = (grpread_info *) g;
  char *start, *end;
  register size_t i;

  /* Idiocy checks.  */
  if (stream == NULL)
    {
      errno = EINVAL;
      return NULL;
    }

  do
    if (__getline (&info->buf, &info->buflen, stream) == -1)
      return NULL;
  while (info->buf[0] == '#');

  start = info->buf;
  end = strchr (start, ':');
  if (end == NULL)
    return NULL;
  *end = '\0';
  info->g.gr_name = start;

  start = end + 1;
  end = strchr (start, ':');
  if (end == NULL)
    return NULL;
  *end = '\0';
  info->g.gr_passwd = start;

  info->g.gr_gid = (gid_t) strtol (end + 1, &end, 10);
  if (*end != ':')
    return NULL;

  i = 0;
  do
    {
      start = end + 1;
      end = strchr (start, ',');
      if (end == NULL)
	{
	  end = strchr (start, '\n');
	  if (end == start)
	    break;
	  if (end == NULL)
	    return NULL;
	  *end = '\0';
	  end = NULL;
	}
      else
	*end = '\0';

      if (i == info->max_members - 2)
	{
	  info->max_members += 5;
	  info->members = (char **)
	    realloc ((PTR) info->members, info->max_members * sizeof (char *));
	  if (info->members == NULL)
	    return NULL;
	}

      info->members[i++] = start;
    } while (end != NULL);
  info->members[i] = NULL;
  info->g.gr_mem = info->members;

  return &info->g;
}


struct group *
__grpscan (void **info, int (*selector) (struct group *))
{
  FILE *stream;
  struct group *p;

  if (*info == NULL)
    {
      *info = __grpalloc ();
      if (info == NULL)
	return NULL;
    }

  stream = __grpopen ();
  if (stream == NULL)
    return NULL;

  p = NULL;
  while (! feof (stream))
    {
      p = __grpread (stream, *info);
      if (p && (*selector) (p))
	break;
      p = NULL;
    }

  (void) fclose (stream);
  return p;
}