blob: a20b3a260b69317744965a9592cd039139bdfa76 [file] [log] [blame]
Robert Griebl1fca5582002-06-04 20:45:46 +00001/*
2 * __getgrent.c - This file is part of the libc-8086/grp package for ELKS,
3 * Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This 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 this library; if not, write to the Free
17 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 *
19 */
20
Robert Griebl1fca5582002-06-04 20:45:46 +000021#include <unistd.h>
22#include <stdlib.h>
23#include <string.h>
Glenn L McGrath4e05b9b2002-12-07 23:14:40 +000024
25#include "busybox.h"
Eric Andersen887ca792002-07-03 23:19:26 +000026#include "grp_.h"
Robert Griebl1fca5582002-06-04 20:45:46 +000027
28/*
29 * Define GR_SCALE_DYNAMIC if you want grp to dynamically scale its read buffer
30 * so that lines of any length can be used. On very very small systems,
31 * you may want to leave this undefined becasue it will make the grp functions
32 * somewhat larger (because of the inclusion of malloc and the code necessary).
33 * On larger systems, you will want to define this, because grp will _not_
34 * deal with long lines gracefully (they will be skipped).
35 */
36#undef GR_SCALE_DYNAMIC
37
38#ifndef GR_SCALE_DYNAMIC
39/*
40 * If scaling is not dynamic, the buffers will be statically allocated, and
41 * maximums must be chosen. GR_MAX_LINE_LEN is the maximum number of
42 * characters per line in the group file. GR_MAX_MEMBERS is the maximum
43 * number of members of any given group.
44 */
45#define GR_MAX_LINE_LEN 128
46/* GR_MAX_MEMBERS = (GR_MAX_LINE_LEN-(24+3+6))/9 */
47#define GR_MAX_MEMBERS 11
48
49#endif /* !GR_SCALE_DYNAMIC */
50
51
52/*
53 * Define GR_DYNAMIC_GROUP_LIST to make initgroups() dynamically allocate
54 * space for it's GID array before calling setgroups(). This is probably
55 * unnecessary scalage, so it's undefined by default.
56 */
57#undef GR_DYNAMIC_GROUP_LIST
58
59#ifndef GR_DYNAMIC_GROUP_LIST
60/*
61 * GR_MAX_GROUPS is the size of the static array initgroups() uses for
62 * its static GID array if GR_DYNAMIC_GROUP_LIST isn't defined.
63 */
64#define GR_MAX_GROUPS 64
65
66#endif /* !GR_DYNAMIC_GROUP_LIST */
67
68
69/*
70 * This is the core group-file read function. It behaves exactly like
71 * getgrent() except that it is passed a file descriptor. getgrent()
72 * is just a wrapper for this function.
73 */
Russ Dillf7967002003-12-18 22:40:58 +000074struct group *bb_getgrent(int grp_fd)
Robert Griebl1fca5582002-06-04 20:45:46 +000075{
76#ifndef GR_SCALE_DYNAMIC
77 static char line_buff[GR_MAX_LINE_LEN];
78 static char *members[GR_MAX_MEMBERS];
79#else
80 static char *line_buff = NULL;
81 static char **members = NULL;
82 short line_index;
83 short buff_size;
84#endif
85 static struct group group;
86 register char *ptr;
87 char *field_begin;
88 short member_num;
89 char *endptr;
90 int line_len;
91
92
93 /* We use the restart label to handle malformatted lines */
94 restart:
95#ifdef GR_SCALE_DYNAMIC
96 line_index = 0;
97 buff_size = 256;
98#endif
99
100#ifndef GR_SCALE_DYNAMIC
101 /* Read the line into the static buffer */
102 if ((line_len = read(grp_fd, line_buff, GR_MAX_LINE_LEN)) <= 0)
103 return NULL;
104 field_begin = strchr(line_buff, '\n');
105 if (field_begin != NULL)
106 lseek(grp_fd, (long) (1 + field_begin - (line_buff + line_len)),
107 SEEK_CUR);
108 else { /* The line is too long - skip it :-\ */
109
110 do {
111 if ((line_len = read(grp_fd, line_buff, GR_MAX_LINE_LEN)) <= 0)
112 return NULL;
113 } while (!(field_begin = strchr(line_buff, '\n')));
114 lseek(grp_fd, (long) ((field_begin - line_buff) - line_len + 1),
115 SEEK_CUR);
116 goto restart;
117 }
118 if (*line_buff == '#' || *line_buff == ' ' || *line_buff == '\n' ||
119 *line_buff == '\t')
120 goto restart;
121 *field_begin = '\0';
122
123#else /* !GR_SCALE_DYNAMIC */
124 line_buff = realloc(line_buff, buff_size);
125 while (1) {
126 if ((line_len = read(grp_fd, line_buff + line_index,
127 buff_size - line_index)) <= 0)
128 return NULL;
129 field_begin = strchr(line_buff, '\n');
130 if (field_begin != NULL) {
131 lseek(grp_fd,
132 (long) (1 + field_begin -
133 (line_len + line_index + line_buff)), SEEK_CUR);
134 *field_begin = '\0';
135 if (*line_buff == '#' || *line_buff == ' '
136 || *line_buff == '\n' || *line_buff == '\t')
137 goto restart;
138 break;
139 } else { /* Allocate some more space */
140
141 line_index = buff_size;
142 buff_size += 256;
143 line_buff = realloc(line_buff, buff_size);
144 }
145 }
146#endif /* GR_SCALE_DYNAMIC */
147
148 /* Now parse the line */
149 group.gr_name = line_buff;
150 ptr = strchr(line_buff, ':');
151 if (ptr == NULL)
152 goto restart;
153 *ptr++ = '\0';
154
155 group.gr_passwd = ptr;
156 ptr = strchr(ptr, ':');
157 if (ptr == NULL)
158 goto restart;
159 *ptr++ = '\0';
160
161 field_begin = ptr;
162 ptr = strchr(ptr, ':');
163 if (ptr == NULL)
164 goto restart;
165 *ptr++ = '\0';
166
167 group.gr_gid = (gid_t) strtoul(field_begin, &endptr, 10);
168 if (*endptr != '\0')
169 goto restart;
170
171 member_num = 0;
172 field_begin = ptr;
173
174#ifndef GR_SCALE_DYNAMIC
175 while ((ptr = strchr(ptr, ',')) != NULL) {
176 *ptr = '\0';
177 ptr++;
178 members[member_num] = field_begin;
179 field_begin = ptr;
180 member_num++;
181 }
182 if (*field_begin == '\0')
183 members[member_num] = NULL;
184 else {
185 members[member_num] = field_begin;
186 members[member_num + 1] = NULL;
187 }
188#else /* !GR_SCALE_DYNAMIC */
Aaron Lehmanna170e1c2002-11-28 11:27:31 +0000189 free(members);
Robert Griebl1fca5582002-06-04 20:45:46 +0000190 members = (char **) malloc((member_num + 1) * sizeof(char *));
191 for ( ; field_begin && *field_begin != '\0'; field_begin = ptr) {
192 if ((ptr = strchr(field_begin, ',')) != NULL)
193 *ptr++ = '\0';
194 members[member_num++] = field_begin;
195 members = (char **) realloc(members,
196 (member_num + 1) * sizeof(char *));
197 }
198 members[member_num] = NULL;
199#endif /* GR_SCALE_DYNAMIC */
200
201 group.gr_mem = members;
202 return &group;
203}