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      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 
     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 
     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 
    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
    145 int main(void)
    146 {
    147 	tst_brkm(TCONF, NULL, "needed mountflags are not defined");
    148 }
    149 #endif
    150