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[glibc.git] / shadow / fgetspent.c
blob902c95eb045366a724a84bb165a0e4151049360f
1 /* Copyright (C) 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 <bits/libc-lock.h>
21 #include <shadow.h>
22 #include <stdlib.h>
25 /* A reasonable size for a buffer to start with. */
26 #define BUFLEN_SPWD 1024
28 /* We need to protect the dynamic buffer handling. */
29 __libc_lock_define_initialized (static, lock);
31 /* Read one shadow entry from the given stream. */
32 struct spwd *
33 fgetspent (FILE *stream)
35 static char *buffer;
36 static size_t buffer_size;
37 static struct spwd resbuf;
38 struct spwd *result;
39 int save;
41 /* Get lock. */
42 __libc_lock_lock (lock);
44 /* Allocate buffer if not yet available. */
45 if (buffer == NULL)
47 buffer_size = BUFLEN_SPWD;
48 buffer = malloc (buffer_size);
51 while (buffer != NULL
52 && __fgetspent_r (stream, &resbuf, buffer, buffer_size, &result) != 0
53 && errno == ERANGE)
55 char *new_buf;
56 buffer_size += BUFLEN_SPWD;
57 new_buf = realloc (buffer, buffer_size);
58 if (new_buf == NULL)
60 /* We are out of memory. Free the current buffer so that the
61 process gets a chance for a normal termination. */
62 save = errno;
63 free (buffer);
64 __set_errno (save);
66 buffer = new_buf;
69 if (buffer == NULL)
70 result = NULL;
72 /* Release lock. Preserve error value. */
73 save = errno;
74 __libc_lock_unlock (lock);
75 __set_errno (save);
77 return result;