blob: b11e9a4d2ae7b35158e2002292e7d62355766b00 [file] [log] [blame]
bigbiff7b4c7a62015-01-01 19:44:14 -05001/* GNU's read utmp module.
2
3 Copyright (C) 1992-2001, 2003-2006, 2009-2014 Free Software Foundation, Inc.
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17
18/* Written by jla; revised by djm */
19/* extracted for util-linux by ooprala */
20
21#include <errno.h>
22#include <stdio.h>
23
24#include <sys/types.h>
25#include <sys/stat.h>
26#include <signal.h>
27#include <stdbool.h>
28#include <string.h>
29#include <stdlib.h>
30#include <stdint.h>
31
32#include "xalloc.h"
33#include "readutmp.h"
34
35/* Read the utmp entries corresponding to file FILE into freshly-
36 malloc'd storage, set *UTMP_BUF to that pointer, set *N_ENTRIES to
37 the number of entries, and return zero. If there is any error,
38 return -1, setting errno, and don't modify the parameters.
39 If OPTIONS & READ_UTMP_CHECK_PIDS is nonzero, omit entries whose
40 process-IDs do not currently exist. */
41int
42read_utmp (char const *file, size_t *n_entries, struct utmp **utmp_buf)
43{
44 size_t n_read = 0;
45 size_t n_alloc = 0;
46 struct utmp *utmp = NULL;
47 struct utmp *u;
48
49 /* Ignore the return value for now.
50 Solaris' utmpname returns 1 upon success -- which is contrary
51 to what the GNU libc version does. In addition, older GNU libc
52 versions are actually void. */
53 utmpname(file);
54
55 setutent();
56
57 errno = 0;
58 while ((u = getutent()) != NULL) {
59 if (n_read == n_alloc) {
60 n_alloc += 32;
61 utmp = xrealloc(utmp, n_alloc * sizeof (struct utmp));
62 if (!utmp)
63 return -1;
64 }
65 utmp[n_read++] = *u;
66 }
67 if (!u && errno) {
68 free(utmp);
69 return -1;
70 }
71
72 endutent();
73
74 *n_entries = n_read;
75 *utmp_buf = utmp;
76
77 return 0;
78}