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>.
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.
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.
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.
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).
36 #undef GR_SCALE_DYNAMIC
38 #ifndef GR_SCALE_DYNAMIC
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.
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
49 #endif /* !GR_SCALE_DYNAMIC */
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.
57 #undef GR_DYNAMIC_GROUP_LIST
59 #ifndef GR_DYNAMIC_GROUP_LIST
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.
64 #define GR_MAX_GROUPS 64
66 #endif /* !GR_DYNAMIC_GROUP_LIST */
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.
74 struct group *__getgrent(int grp_fd)
76 #ifndef GR_SCALE_DYNAMIC
77 static char line_buff[GR_MAX_LINE_LEN];
78 static char *members[GR_MAX_MEMBERS];
80 static char *line_buff = NULL;
81 static char **members = NULL;
85 static struct group group;
93 /* We use the restart label to handle malformatted lines */
95 #ifdef GR_SCALE_DYNAMIC
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)
104 field_begin = strchr(line_buff, '\n');
105 if (field_begin != NULL)
106 lseek(grp_fd, (long) (1 + field_begin - (line_buff + line_len)),
108 else { /* The line is too long - skip it :-\ */
111 if ((line_len = read(grp_fd, line_buff, GR_MAX_LINE_LEN)) <= 0)
113 } while (!(field_begin = strchr(line_buff, '\n')));
114 lseek(grp_fd, (long) ((field_begin - line_buff) - line_len + 1),
118 if (*line_buff == '#' || *line_buff == ' ' || *line_buff == '\n' ||
123 #else /* !GR_SCALE_DYNAMIC */
124 line_buff = realloc(line_buff, buff_size);
126 if ((line_len = read(grp_fd, line_buff + line_index,
127 buff_size - line_index)) <= 0)
129 field_begin = strchr(line_buff, '\n');
130 if (field_begin != NULL) {
132 (long) (1 + field_begin -
133 (line_len + line_index + line_buff)), SEEK_CUR);
135 if (*line_buff == '#' || *line_buff == ' '
136 || *line_buff == '\n' || *line_buff == '\t')
139 } else { /* Allocate some more space */
141 line_index = buff_size;
143 line_buff = realloc(line_buff, buff_size);
146 #endif /* GR_SCALE_DYNAMIC */
148 /* Now parse the line */
149 group.gr_name = line_buff;
150 ptr = strchr(line_buff, ':');
155 group.gr_passwd = ptr;
156 ptr = strchr(ptr, ':');
162 ptr = strchr(ptr, ':');
167 group.gr_gid = (gid_t) strtoul(field_begin, &endptr, 10);
174 #ifndef GR_SCALE_DYNAMIC
175 while ((ptr = strchr(ptr, ',')) != NULL) {
178 members[member_num] = field_begin;
182 if (*field_begin == '\0')
183 members[member_num] = NULL;
185 members[member_num] = field_begin;
186 members[member_num + 1] = NULL;
188 #else /* !GR_SCALE_DYNAMIC */
190 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)
194 members[member_num++] = field_begin;
195 members = (char **) realloc(members,
196 (member_num + 1) * sizeof(char *));
198 members[member_num] = NULL;
199 #endif /* GR_SCALE_DYNAMIC */
201 group.gr_mem = members;