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[glibc.git] / grp / fgetgrent.c
blob24fdcd86d9150574f4d11155ccc5adddf2244084
1 /* Copyright (C) 1991, 1996, 1997 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 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.
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.
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 not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
19 #include <errno.h>
20 #include <grp.h>
21 #include <bits/libc-lock.h>
22 #include <stdlib.h>
25 /* We need to protect the dynamic buffer handling. */
26 __libc_lock_define_initialized (static, lock);
28 /* Read one entry from the given stream. */
29 struct group *
30 fgetgrent (FILE *stream)
32 static char *buffer;
33 static size_t buffer_size;
34 static struct group resbuf;
35 struct group *result;
36 int save;
38 /* Get lock. */
39 __libc_lock_lock (lock);
41 /* Allocate buffer if not yet available. */
42 if (buffer == NULL)
44 buffer_size = NSS_BUFLEN_GROUP;
45 buffer = malloc (buffer_size);
48 while (buffer != NULL
49 && __fgetgrent_r (stream, &resbuf, buffer, buffer_size, &result) != 0
50 && errno == ERANGE)
52 char *new_buf;
53 buffer_size += NSS_BUFLEN_GROUP;
54 new_buf = realloc (buffer, buffer_size);
55 if (new_buf == NULL)
57 /* We are out of memory. Free the current buffer so that the
58 process gets a chance for a normal termination. */
59 save = errno;
60 free (buffer);
61 __set_errno (save);
63 buffer = new_buf;
66 if (buffer == NULL)
67 result = NULL;
69 /* Release lock. Preserve error value. */
70 save = errno;
71 __libc_lock_unlock (lock);
72 __set_errno (save);
74 return result;