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 "mountns_helper.h"
48 #include "test.h"
49 #include "safe_macros.h"
50
51 char *TCID = "mountns03";
52 int TST_TOTAL = 2;
53
54 #if defined(MS_SHARED) && defined(MS_PRIVATE) \
55 && defined(MS_REC) && defined(MS_SLAVE)
56
child_func(void * arg LTP_ATTRIBUTE_UNUSED)57 int child_func(void *arg LTP_ATTRIBUTE_UNUSED)
58 {
59 int ret = 0;
60
61 /* makes mount DIRA a slave of DIRA (all slave mounts have
62 * a master mount which is a shared mount) */
63 if (mount("none", DIRA, "none", MS_SLAVE, NULL) == -1) {
64 perror("mount");
65 return 1;
66 }
67
68 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
69
70 /* checks that shared mounts propagates to slave mount */
71 if (access(DIRA"/B", F_OK) == -1)
72 ret = 2;
73
74 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
75
76 /* bind mounts DIRB to DIRA making contents of DIRB visible
77 * in DIRA */
78 if (mount(DIRB, DIRA, "none", MS_BIND, NULL) == -1) {
79 perror("mount");
80 return 1;
81 }
82
83 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
84
85 umount(DIRA);
86 return ret;
87 }
88
test(void)89 static void test(void)
90 {
91 int status;
92
93 /* unshares the mount ns */
94 if (unshare(CLONE_NEWNS) == -1)
95 tst_brkm(TBROK | TERRNO, cleanup, "unshare failed");
96 /* makes sure parent mounts/umounts have no effect on a real system */
97 SAFE_MOUNT(cleanup, "none", "/", "none", MS_REC|MS_PRIVATE, NULL);
98
99 /* bind mounts DIRA to itself */
100 SAFE_MOUNT(cleanup, DIRA, DIRA, "none", MS_BIND, NULL);
101
102 /* makes mount DIRA shared */
103 SAFE_MOUNT(cleanup, "none", DIRA, "none", MS_SHARED, NULL);
104
105 if (do_clone_tests(CLONE_NEWNS, child_func, NULL, NULL, NULL) == -1)
106 tst_brkm(TBROK | TERRNO, cleanup, "clone failed");
107
108 /* waits for child to make a slave mount */
109 TST_SAFE_CHECKPOINT_WAIT(cleanup, 0);
110
111 /* bind mounts DIRB to DIRA making contents of DIRB visible
112 * in DIRA */
113 SAFE_MOUNT(cleanup, DIRB, DIRA, "none", MS_BIND, NULL);
114
115 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(cleanup, 0);
116
117 SAFE_UMOUNT(cleanup, DIRA);
118
119 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(cleanup, 0);
120
121 /* checks that slave mount doesn't propagate to shared mount */
122 if ((access(DIRA"/A", F_OK) == 0) && (access(DIRA"/B", F_OK) == -1))
123 tst_resm(TPASS, "propagation from slave mount passed");
124 else
125 tst_resm(TFAIL, "propagation form slave mount failed");
126
127 TST_SAFE_CHECKPOINT_WAKE(cleanup, 0);
128
129
130 SAFE_WAIT(cleanup, &status);
131 if (WIFEXITED(status)) {
132 if (WEXITSTATUS(status) == 0)
133 tst_resm(TPASS, "propagation to slave mount passed");
134 else
135 tst_resm(TFAIL, "propagation to slave mount failed");
136 }
137 if (WIFSIGNALED(status)) {
138 tst_resm(TBROK, "child was killed with signal %s",
139 tst_strsig(WTERMSIG(status)));
140 return;
141 }
142
143 SAFE_UMOUNT(cleanup, DIRA);
144 }
145
main(int argc,char * argv[])146 int main(int argc, char *argv[])
147 {
148 int lc;
149
150 tst_parse_opts(argc, argv, NULL, NULL);
151
152 setup();
153
154 for (lc = 0; TEST_LOOPING(lc); lc++)
155 test();
156
157 cleanup();
158 tst_exit();
159 }
160
161 #else
main(void)162 int main(void)
163 {
164 tst_brkm(TCONF, NULL, "needed mountflags are not defined");
165 }
166 #endif
167