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 <stdio.h>
22#include <stdlib.h>
23#include <set-freeres.h>
24
25
26/* A reasonable size for a buffer to start with. */
27#define BUFLEN_SPWD 1024
28
29/* We need to protect the dynamic buffer handling. */
30__libc_lock_define_initialized (static, lock);
31
32static char *buffer;
33
34/* Read one shadow entry from the given stream. */
35struct sgrp *
36fgetsgent (FILE *stream)
37{
38 static size_t buffer_size;
39 static struct sgrp resbuf;
40 fpos_t pos;
41 struct sgrp *result;
42 int save;
43
44 if (fgetpos (stream, &pos) != 0)
45 return NULL;
46
47 /* Get lock. */
48 __libc_lock_lock (lock);
49
50 /* Allocate buffer if not yet available. */
51 if (buffer == NULL)
52 {
53 buffer_size = BUFLEN_SPWD;
54 buffer = malloc (buffer_size);
55 }
56
57 while (buffer != NULL
58 && (__fgetsgent_r (stream, &resbuf, buffer, buffer_size, &result)
59 == ERANGE))
60 {
61 char *new_buf;
62 buffer_size += BUFLEN_SPWD;
63 new_buf = realloc (buffer, buffer_size);
64 if (new_buf == NULL)
65 {
66 /* We are out of memory. Free the current buffer so that the
67 process gets a chance for a normal termination. */
68 save = errno;
69 free (buffer);
70 __set_errno (save);
71 }
72 buffer = new_buf;
73
74 /* Reset the stream. */
75 if (fsetpos (stream, &pos) != 0)
76 buffer = NULL;
77 }
78
79 if (buffer == NULL)
80 result = NULL;
81
82 /* Release lock. Preserve error value. */
83 save = errno;
84 __libc_lock_unlock (lock);
85 __set_errno (save);
86
87 return result;
88}
89
90weak_alias (buffer, __libc_fgetsgent_freeres_ptr);
91