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
53 char *TCID = "mountns03";
54 int TST_TOTAL = 2;
55
56
57 #if defined(MS_SHARED) && defined(MS_PRIVATE) \
58 && defined(MS_REC) && defined(MS_SLAVE)
59
child_func(void * arg LTP_ATTRIBUTE_UNUSED)60 int 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
test(void)92 static 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
main(int argc,char * argv[])149 int 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
main(void)165 int main(void)
166 {
167 tst_brkm(TCONF, NULL, "needed mountflags are not defined");
168 }
169 #endif
170