Home | History | Annotate | Download | only in mountns 
      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 
     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 
     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 
    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
    162 int main(void)
    163 {
    164 	tst_brkm(TCONF, NULL, "needed mountflags are not defined");
    165 }
    166 #endif
    167