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: mountns01.c
16 *
17 * Tests a shared mount: shared mount can be replicated to as many
18 * mountpoints and all the replicas continue to be exactly same.
19 * Description:
20 * 1. Creates directories "A", "B" and files "A/A", "B/B"
21 * 2. Unshares mount namespace and makes it private (so mounts/umounts
22 * have no effect on a real system)
23 * 3. Bind mounts directory "A" to "A"
24 * 4. Makes directory "A" shared
25 * 5. Clones a new child process with CLONE_NEWNS flag
26 * 6. There are two test cases (where X is parent namespace and Y child
27 * namespace):
28 * 1)
29 * X: bind mounts "B" to "A"
30 * Y: must see "A/B"
31 * X: umounts "A"
32 * 2)
33 * Y: bind mounts "B" to "A"
34 * X: must see "A/B"
35 * Y: umounts "A"
36 ***********************************************************************/
37
38 #define _GNU_SOURCE
39 #include <sys/wait.h>
40 #include <sys/mount.h>
41 #include <stdio.h>
42 #include <errno.h>
43 #include "mountns_helper.h"
44 #include "test.h"
45 #include "safe_macros.h"
46
47 char *TCID = "mountns01";
48 int TST_TOTAL = 2;
49
50 #if defined(MS_SHARED) && defined(MS_PRIVATE) && defined(MS_REC)
51
child_func(void * arg LTP_ATTRIBUTE_UNUSED)52 int child_func(void *arg LTP_ATTRIBUTE_UNUSED)
53 {
54 int ret = 0;
55
56 TST_SAFE_CHECKPOINT_WAIT(NULL, 0);
57
58 if (access(DIRA"/B", F_OK) == -1)
59 ret = 2;
60
61 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
62
63 /* bind mounts DIRB to DIRA making contents of DIRB visible
64 * in DIRA */
65 if (mount(DIRB, DIRA, "none", MS_BIND, NULL) == -1) {
66 perror("mount");
67 return 1;
68 }
69
70 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
71
72 umount(DIRA);
73 return ret;
74 }
75
test(void)76 static void test(void)
77 {
78 int status;
79
80 /* unshares the mount ns */
81 if (unshare(CLONE_NEWNS) == -1)
82 tst_brkm(TBROK | TERRNO, cleanup, "unshare failed");
83 /* makes sure parent mounts/umounts have no effect on a real system */
84 SAFE_MOUNT(cleanup, "none", "/", "none", MS_REC|MS_PRIVATE, NULL);
85
86 /* bind mounts DIRA to itself */
87 SAFE_MOUNT(cleanup, DIRA, DIRA, "none", MS_BIND, NULL);
88
89 /* makes mount DIRA shared */
90 SAFE_MOUNT(cleanup, "none", DIRA, "none", MS_SHARED, NULL);
91
92 if (do_clone_tests(CLONE_NEWNS, child_func, NULL, NULL, NULL) == -1)
93 tst_brkm(TBROK | TERRNO, cleanup, "clone failed");
94
95 /* bind mounts DIRB to DIRA making contents of DIRB visible
96 * in DIRA */
97 SAFE_MOUNT(cleanup, DIRB, DIRA, "none", MS_BIND, NULL);
98
99 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(cleanup, 0);
100
101 SAFE_UMOUNT(cleanup, DIRA);
102
103 TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(cleanup, 0);
104
105 if (access(DIRA"/B", F_OK) == 0)
106 tst_resm(TPASS, "shared mount in child passed");
107 else
108 tst_resm(TFAIL, "shared mount in child failed");
109
110 TST_SAFE_CHECKPOINT_WAKE(cleanup, 0);
111
112
113 SAFE_WAIT(cleanup, &status);
114 if (WIFEXITED(status)) {
115 if ((WEXITSTATUS(status) == 0))
116 tst_resm(TPASS, "shared mount in parent passed");
117 else
118 tst_resm(TFAIL, "shared mount in parent failed");
119 }
120 if (WIFSIGNALED(status)) {
121 tst_resm(TBROK, "child was killed with signal %s",
122 tst_strsig(WTERMSIG(status)));
123 return;
124 }
125
126 SAFE_UMOUNT(cleanup, DIRA);
127 }
128
main(int argc,char * argv[])129 int main(int argc, char *argv[])
130 {
131 int lc;
132
133 tst_parse_opts(argc, argv, NULL, NULL);
134
135 setup();
136
137 for (lc = 0; TEST_LOOPING(lc); lc++)
138 test();
139
140 cleanup();
141 tst_exit();
142 }
143
144 #else
main(void)145 int main(void)
146 {
147 tst_brkm(TCONF, NULL, "needed mountflags are not defined");
148 }
149 #endif
150