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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: 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 
     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 
     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 
    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
    165 int main(void)
    166 {
    167 	tst_brkm(TCONF, NULL, "needed mountflags are not defined");
    168 }
    169 #endif
    170