1/* Copyright (C) 2009-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
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.
8
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.
13
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 <https://www.gnu.org/licenses/>. */
17
18#include <errno.h>
19#include <libc-lock.h>
20#include <gshadow.h>
21#include <stdlib.h>
22
23
24/* A reasonable size for a buffer to start with. */
25#define BUFLEN_SPWD 1024
26
27/* We need to protect the dynamic buffer handling. */
28__libc_lock_define_initialized (static, lock);
29
30/* Read one shadow entry from the given stream. */
31struct sgrp *
32sgetsgent (const char *string)
33{
34 static char *buffer;
35 static size_t buffer_size;
36 static struct sgrp resbuf;
37 struct sgrp *result;
38 int save;
39
40 /* Get lock. */
41 __libc_lock_lock (lock);
42
43 /* Allocate buffer if not yet available. */
44 if (buffer == NULL)
45 {
46 buffer_size = BUFLEN_SPWD;
47 buffer = malloc (buffer_size);
48 }
49
50 while (buffer != NULL
51 && __sgetsgent_r (string, &resbuf, buffer, buffer_size, &result) != 0
52 && errno == ERANGE)
53 {
54 char *new_buf;
55 buffer_size += BUFLEN_SPWD;
56 new_buf = realloc (buffer, buffer_size);
57 if (new_buf == NULL)
58 {
59 /* We are out of memory. Free the current buffer so that the
60 process gets a chance for a normal termination. */
61 save = errno;
62 free (buffer);
63 __set_errno (save);
64 }
65 buffer = new_buf;
66 }
67
68 if (buffer == NULL)
69 result = NULL;
70
71 /* Release lock. Preserve error value. */
72 save = errno;
73 __libc_lock_unlock (lock);
74 __set_errno (save);
75
76 return result;
77}
78