Do not create invalid pointers in C code of string functions.
[glibc.git] / grp / grp.h
blobff0ad026650eca964d071bd115caf74c6309f239
1 /* Copyright (C) 1991-2015 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
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 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
19 * POSIX Standard: 9.2.1 Group Database Access <grp.h>
22 #ifndef _GRP_H
23 #define _GRP_H 1
25 #include <features.h>
27 __BEGIN_DECLS
29 #include <bits/types.h>
31 #define __need_size_t
32 #include <stddef.h>
35 /* For the Single Unix specification we must define this type here. */
36 #if (defined __USE_XOPEN || defined __USE_XOPEN2K) && !defined __gid_t_defined
37 typedef __gid_t gid_t;
38 # define __gid_t_defined
39 #endif
41 /* The group structure. */
42 struct group
44 char *gr_name; /* Group name. */
45 char *gr_passwd; /* Password. */
46 __gid_t gr_gid; /* Group ID. */
47 char **gr_mem; /* Member list. */
51 #ifdef __USE_MISC
52 # define __need_FILE
53 # include <stdio.h>
54 #endif
57 #if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
58 /* Rewind the group-file stream.
60 This function is a possible cancellation point and therefore not
61 marked with __THROW. */
62 extern void setgrent (void);
64 /* Close the group-file stream.
66 This function is a possible cancellation point and therefore not
67 marked with __THROW. */
68 extern void endgrent (void);
70 /* Read an entry from the group-file stream, opening it if necessary.
72 This function is a possible cancellation point and therefore not
73 marked with __THROW. */
74 extern struct group *getgrent (void);
75 #endif
77 #ifdef __USE_MISC
78 /* Read a group entry from STREAM.
80 This function is not part of POSIX and therefore no official
81 cancellation point. But due to similarity with an POSIX interface
82 or due to the implementation it is a cancellation point and
83 therefore not marked with __THROW. */
84 extern struct group *fgetgrent (FILE *__stream);
85 #endif
87 #ifdef __USE_GNU
88 /* Write the given entry onto the given stream.
90 This function is not part of POSIX and therefore no official
91 cancellation point. But due to similarity with an POSIX interface
92 or due to the implementation it is a cancellation point and
93 therefore not marked with __THROW. */
94 extern int putgrent (const struct group *__restrict __p,
95 FILE *__restrict __f);
96 #endif
98 /* Search for an entry with a matching group ID.
100 This function is a possible cancellation point and therefore not
101 marked with __THROW. */
102 extern struct group *getgrgid (__gid_t __gid);
104 /* Search for an entry with a matching group name.
106 This function is a possible cancellation point and therefore not
107 marked with __THROW. */
108 extern struct group *getgrnam (const char *__name);
110 #ifdef __USE_POSIX
112 # ifdef __USE_MISC
113 /* Reasonable value for the buffer sized used in the reentrant
114 functions below. But better use `sysconf'. */
115 # define NSS_BUFLEN_GROUP 1024
116 # endif
118 /* Reentrant versions of some of the functions above.
120 PLEASE NOTE: the `getgrent_r' function is not (yet) standardized.
121 The interface may change in later versions of this library. But
122 the interface is designed following the principals used for the
123 other reentrant functions so the chances are good this is what the
124 POSIX people would choose.
126 This function is not part of POSIX and therefore no official
127 cancellation point. But due to similarity with an POSIX interface
128 or due to the implementation it is a cancellation point and
129 therefore not marked with __THROW. */
131 # ifdef __USE_GNU
132 extern int getgrent_r (struct group *__restrict __resultbuf,
133 char *__restrict __buffer, size_t __buflen,
134 struct group **__restrict __result);
135 # endif
137 /* Search for an entry with a matching group ID.
139 This function is a possible cancellation point and therefore not
140 marked with __THROW. */
141 extern int getgrgid_r (__gid_t __gid, struct group *__restrict __resultbuf,
142 char *__restrict __buffer, size_t __buflen,
143 struct group **__restrict __result);
145 /* Search for an entry with a matching group name.
147 This function is a possible cancellation point and therefore not
148 marked with __THROW. */
149 extern int getgrnam_r (const char *__restrict __name,
150 struct group *__restrict __resultbuf,
151 char *__restrict __buffer, size_t __buflen,
152 struct group **__restrict __result);
154 # ifdef __USE_MISC
155 /* Read a group entry from STREAM. This function is not standardized
156 an probably never will.
158 This function is not part of POSIX and therefore no official
159 cancellation point. But due to similarity with an POSIX interface
160 or due to the implementation it is a cancellation point and
161 therefore not marked with __THROW. */
162 extern int fgetgrent_r (FILE *__restrict __stream,
163 struct group *__restrict __resultbuf,
164 char *__restrict __buffer, size_t __buflen,
165 struct group **__restrict __result);
166 # endif
168 #endif /* POSIX or reentrant */
171 #ifdef __USE_MISC
173 # define __need_size_t
174 # include <stddef.h>
176 /* Set the group set for the current user to GROUPS (N of them). */
177 extern int setgroups (size_t __n, const __gid_t *__groups) __THROW;
179 /* Store at most *NGROUPS members of the group set for USER into
180 *GROUPS. Also include GROUP. The actual number of groups found is
181 returned in *NGROUPS. Return -1 if the if *NGROUPS is too small.
183 This function is not part of POSIX and therefore no official
184 cancellation point. But due to similarity with an POSIX interface
185 or due to the implementation it is a cancellation point and
186 therefore not marked with __THROW. */
187 extern int getgrouplist (const char *__user, __gid_t __group,
188 __gid_t *__groups, int *__ngroups);
190 /* Initialize the group set for the current user
191 by reading the group database and using all groups
192 of which USER is a member. Also include GROUP.
194 This function is not part of POSIX and therefore no official
195 cancellation point. But due to similarity with an POSIX interface
196 or due to the implementation it is a cancellation point and
197 therefore not marked with __THROW. */
198 extern int initgroups (const char *__user, __gid_t __group);
200 #endif /* Use misc. */
202 __END_DECLS
204 #endif /* grp.h */