1/* Basic test for gethostid.
2 Copyright (C) 2018-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <gnu/lib-names.h>
20#include <nss.h>
21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
24#include <support/namespace.h>
25#include <support/support.h>
26#include <support/temp_file.h>
27#include <support/xdlfcn.h>
28#include <support/xstdio.h>
29#include <support/xunistd.h>
30#include <unistd.h>
31
32/* Initial test is run outside a chroot, to increase the likelihood of
33 success. */
34static void
35outside_chroot (void *closure)
36{
37 long id = gethostid ();
38 printf (format: "info: host ID outside chroot: 0x%lx\n", id);
39}
40
41/* The same, but this time perform a chroot operation. */
42static void
43in_chroot (void *closure)
44{
45 const char *chroot_path = closure;
46 xchroot (path: chroot_path);
47 long id = gethostid ();
48 printf (format: "info: host ID in chroot: 0x%lx\n", id);
49}
50
51static int
52do_test (void)
53{
54 support_isolate_in_subprocess (callback: outside_chroot, NULL);
55
56 /* Now run the test inside a chroot. */
57 support_become_root ();
58 if (!support_can_chroot ())
59 /* Cannot perform further tests. */
60 return 0;
61
62 /* Only use nss_files. */
63 __nss_configure_lookup (dbname: "hosts", string: "files");
64
65 /* Load the DSO outside of the chroot. */
66 xdlopen (LIBNSS_FILES_SO, RTLD_LAZY);
67
68 char *chroot_dir = support_create_temp_directory (base: "tst-gethostid-");
69 support_isolate_in_subprocess (callback: in_chroot, closure: chroot_dir);
70
71 /* Tests with /etc/hosts in the chroot. */
72 {
73 char *path = xasprintf (format: "%s/etc", chroot_dir);
74 add_temp_file (name: path);
75 xmkdir (path, 0777);
76 free (ptr: path);
77 path = xasprintf (format: "%s/etc/hosts", chroot_dir);
78 add_temp_file (name: path);
79
80 FILE *fp = xfopen (path, mode: "w");
81 xfclose (fp);
82 printf (format: "info: chroot test with an empty /etc/hosts file\n");
83 support_isolate_in_subprocess (callback: in_chroot, closure: chroot_dir);
84
85 char hostname[1024];
86 int ret = gethostname (name: hostname, len: sizeof (hostname));
87 if (ret < 0)
88 printf (format: "warning: invalid result from gethostname: %d\n", ret);
89 else if (strlen (hostname) == 0)
90 puts (s: "warning: gethostname returned empty string");
91 else
92 {
93 printf (format: "info: chroot test with IPv6 address in /etc/hosts for: %s\n",
94 hostname);
95 fp = xfopen (path, mode: "w");
96 /* Use an IPv6 address to induce another lookup failure. */
97 fprintf (fp, "2001:db8::1 %s\n", hostname);
98 xfclose (fp);
99 support_isolate_in_subprocess (callback: in_chroot, closure: chroot_dir);
100 }
101 free (ptr: path);
102 }
103 free (ptr: chroot_dir);
104
105 return 0;
106}
107
108#include <support/test-driver.c>
109

source code of glibc/misc/tst-gethostid.c