1/* Copyright (c) 2014 Red Hat, Inc.
2 *
3 * This program is free software: you can redistribute it and/or modify
4 * it under the terms of version 2 the GNU General Public License as
5 * published by the Free Software Foundation.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
10 * GNU General Public License for more details.
11 *
12 * You should have received a copy of the GNU General Public License
13 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
14 ***********************************************************************
15 * File: mountns03.c
16 *
17 * Tests a slave mount: slave mount is like a shared mount except that
18 * mount and umount events only propagate towards it.
19 *
20 * Description:
21 * 1. Creates directories "A", "B" and files "A/A", "B/B"
22 * 2. Unshares mount namespace and makes it private (so mounts/umounts
23 *    have no effect on a real system)
24 * 3. Bind mounts directory "A" to itself
25 * 4. Makes directory "A" shared
26 * 5. Clones a new child process with CLONE_NEWNS flag and makes "A"
27 *    a slave mount
28 * 6. There are two testcases (where X is parent namespace and Y child
29 *    namespace):
30 *    1)
31 *	X: bind mounts "B" to "A"
32 *	Y: must see the file "A/B"
33 *	X: umounts "A"
34 *    2)
35 *	Y: bind mounts "B" to "A"
36 *	X: must see only the "A/A" and must not see "A/B" (as slave
37 *	   mount does not forward propagation)
38 *	Y: umounts "A"
39 ***********************************************************************/
40
41#define _GNU_SOURCE
42#include <sys/wait.h>
43#include <sys/mount.h>
44#include <stdio.h>
45#include <unistd.h>
46#include <errno.h>
47#include "test.h"
48#include "libclone.h"
49#include "safe_macros.h"
50#include "mountns_helper.h"
51
52
53char *TCID	= "mountns03";
54int TST_TOTAL	= 2;
55
56
57#if defined(MS_SHARED) && defined(MS_PRIVATE) \
58    && defined(MS_REC) && defined(MS_SLAVE)
59
60int child_func(void *arg LTP_ATTRIBUTE_UNUSED)
61{
62	int ret = 0;
63
64	/* makes mount DIRA a slave of DIRA (all slave mounts have
65	 * a master mount which is a shared mount) */
66	if (mount("none", DIRA, "none", MS_SLAVE, NULL) == -1) {
67		perror("mount");
68		return 1;
69	}
70
71	TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
72
73	/* checks that shared mounts propagates to slave mount */
74	if (access(DIRA"/B", F_OK) == -1)
75		ret = 2;
76
77	TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
78
79	/* bind mounts DIRB to DIRA making contents of DIRB visible
80	 * in DIRA */
81	if (mount(DIRB, DIRA, "none", MS_BIND, NULL) == -1) {
82		perror("mount");
83		return 1;
84	}
85
86	TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
87
88	umount(DIRA);
89	return ret;
90}
91
92static void test(void)
93{
94	int status;
95
96	/* unshares the mount ns */
97	if (unshare(CLONE_NEWNS) == -1)
98		tst_brkm(TBROK | TERRNO, cleanup, "unshare failed");
99	/* makes sure parent mounts/umounts have no effect on a real system */
100	SAFE_MOUNT(cleanup, "none", "/", "none", MS_REC|MS_PRIVATE, NULL);
101
102	/* bind mounts DIRA to itself */
103	SAFE_MOUNT(cleanup, DIRA, DIRA, "none", MS_BIND, NULL);
104
105	/* makes mount DIRA shared */
106	SAFE_MOUNT(cleanup, "none", DIRA, "none", MS_SHARED, NULL);
107
108	if (do_clone_tests(CLONE_NEWNS, child_func, NULL, NULL, NULL) == -1)
109		tst_brkm(TBROK | TERRNO, cleanup, "clone failed");
110
111	/* waits for child to make a slave mount */
112	TST_SAFE_CHECKPOINT_WAIT(cleanup, 0);
113
114	/* bind mounts DIRB to DIRA making contents of DIRB visible
115	 * in DIRA */
116	SAFE_MOUNT(cleanup, DIRB, DIRA, "none", MS_BIND, NULL);
117
118	TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(cleanup, 0);
119
120	SAFE_UMOUNT(cleanup, DIRA);
121
122	TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(cleanup, 0);
123
124	/* checks that slave mount doesn't propagate to shared mount */
125	if ((access(DIRA"/A", F_OK) == 0) && (access(DIRA"/B", F_OK) == -1))
126		tst_resm(TPASS, "propagation from slave mount passed");
127	else
128		tst_resm(TFAIL, "propagation form slave mount failed");
129
130	TST_SAFE_CHECKPOINT_WAKE(cleanup, 0);
131
132
133	SAFE_WAIT(cleanup, &status);
134	if (WIFEXITED(status)) {
135		if (WEXITSTATUS(status) == 0)
136			tst_resm(TPASS, "propagation to slave mount passed");
137		else
138			tst_resm(TFAIL, "propagation to slave mount failed");
139	}
140	if (WIFSIGNALED(status)) {
141		tst_resm(TBROK, "child was killed with signal %s",
142			 tst_strsig(WTERMSIG(status)));
143		return;
144	}
145
146	SAFE_UMOUNT(cleanup, DIRA);
147}
148
149int main(int argc, char *argv[])
150{
151	int lc;
152
153	tst_parse_opts(argc, argv, NULL, NULL);
154
155	setup();
156
157	for (lc = 0; TEST_LOOPING(lc); lc++)
158		test();
159
160	cleanup();
161	tst_exit();
162}
163
164#else
165int main(void)
166{
167	tst_brkm(TCONF, NULL, "needed mountflags are not defined");
168}
169#endif
170