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04277e02 | 1 | /* Copyright (C) 2009-2019 Free Software Foundation, Inc. |
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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 | |
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15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
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17 | |
18 | #include <errno.h> | |
ec999b8e | 19 | #include <libc-lock.h> |
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20 | #include <gshadow.h> |
21 | #include <stdio.h> | |
22 | #include <stdlib.h> | |
23 | ||
24 | ||
25 | /* A reasonable size for a buffer to start with. */ | |
26 | #define BUFLEN_SPWD 1024 | |
27 | ||
28 | /* We need to protect the dynamic buffer handling. */ | |
29 | __libc_lock_define_initialized (static, lock); | |
30 | ||
31 | libc_freeres_ptr (static char *buffer); | |
32 | ||
33 | /* Read one shadow entry from the given stream. */ | |
34 | struct sgrp * | |
35 | fgetsgent (FILE *stream) | |
36 | { | |
37 | static size_t buffer_size; | |
38 | static struct sgrp resbuf; | |
39 | fpos_t pos; | |
40 | struct sgrp *result; | |
41 | int save; | |
42 | ||
43 | if (fgetpos (stream, &pos) != 0) | |
44 | return NULL; | |
45 | ||
46 | /* Get lock. */ | |
47 | __libc_lock_lock (lock); | |
48 | ||
49 | /* Allocate buffer if not yet available. */ | |
50 | if (buffer == NULL) | |
51 | { | |
52 | buffer_size = BUFLEN_SPWD; | |
53 | buffer = malloc (buffer_size); | |
54 | } | |
55 | ||
56 | while (buffer != NULL | |
57 | && (__fgetsgent_r (stream, &resbuf, buffer, buffer_size, &result) | |
58 | == ERANGE)) | |
59 | { | |
60 | char *new_buf; | |
61 | buffer_size += BUFLEN_SPWD; | |
62 | new_buf = realloc (buffer, buffer_size); | |
63 | if (new_buf == NULL) | |
64 | { | |
65 | /* We are out of memory. Free the current buffer so that the | |
66 | process gets a chance for a normal termination. */ | |
67 | save = errno; | |
68 | free (buffer); | |
69 | __set_errno (save); | |
70 | } | |
71 | buffer = new_buf; | |
72 | ||
73 | /* Reset the stream. */ | |
74 | if (fsetpos (stream, &pos) != 0) | |
75 | buffer = NULL; | |
76 | } | |
77 | ||
78 | if (buffer == NULL) | |
79 | result = NULL; | |
80 | ||
81 | /* Release lock. Preserve error value. */ | |
82 | save = errno; | |
83 | __libc_lock_unlock (lock); | |
84 | __set_errno (save); | |
85 | ||
86 | return result; | |
87 | } |