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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: shm_comm.c
     16  *
     17  * Description:
     18  * 1. Clones two child processes with CLONE_NEWIPC flag, each child
     19  *    allocates System V shared memory segment (shm) with the _identical_
     20  *    key and attaches that segment into its address space.
     21  * 2. Child1 writes into the shared memory segment.
     22  * 3. Child2 writes into the shared memory segment.
     23  * 4. Writes to the shared memory segment with the identical key but from
     24  *    two different IPC namespaces should not interfere with each other
     25  *    and so child1 checks whether its shared segment wasn't changed
     26  *    by child2, if it wasn't test passes, otherwise test fails.
     27  */
     28 
     29 #define _GNU_SOURCE
     30 #include <sys/ipc.h>
     31 #include <sys/shm.h>
     32 #include <sys/types.h>
     33 #include <sys/wait.h>
     34 #include <stdio.h>
     35 #include <errno.h>
     36 #include "test.h"
     37 #include "safe_macros.h"
     38 #include "libclone.h"
     39 #include "ipcns_helper.h"
     40 
     41 
     42 #define TESTKEY 124426L
     43 #define SHMSIZE 50
     44 char *TCID	= "shm_comm";
     45 int TST_TOTAL	= 1;
     46 
     47 static void cleanup(void)
     48 {
     49 	tst_rmdir();
     50 }
     51 
     52 static void setup(void)
     53 {
     54 	tst_require_root();
     55 	check_newipc();
     56 	tst_tmpdir();
     57 	TST_CHECKPOINT_INIT(tst_rmdir);
     58 }
     59 
     60 int chld1_shm(void *arg)
     61 {
     62 	int id, rval = 0;
     63 	char *shmem;
     64 
     65 	id = shmget(TESTKEY, SHMSIZE, IPC_CREAT);
     66 	if (id == -1) {
     67 		perror("shmget");
     68 		return 2;
     69 	}
     70 
     71 	if ((shmem = shmat(id, NULL, 0)) == (char *) -1) {
     72 		perror("shmat");
     73 		shmctl(id, IPC_RMID, NULL);
     74 		return 2;
     75 	}
     76 
     77 	*shmem = 'A';
     78 
     79 	TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
     80 
     81 	/* if child1 shared segment has changed (by child2) report fail */
     82 	if (*shmem != 'A')
     83 		rval = 1;
     84 
     85 	/* tell child2 to continue */
     86 	TST_SAFE_CHECKPOINT_WAKE(NULL, 0);
     87 
     88 	shmdt(shmem);
     89 	shmctl(id, IPC_RMID, NULL);
     90 	return rval;
     91 }
     92 
     93 int chld2_shm(void *arg)
     94 {
     95 	int id;
     96 	char *shmem;
     97 
     98 	id = shmget(TESTKEY, SHMSIZE, IPC_CREAT);
     99 	if (id == -1) {
    100 		perror("shmget");
    101 		return 2;
    102 	}
    103 
    104 	if ((shmem = shmat(id, NULL, 0)) == (char *) -1) {
    105 		perror("shmat");
    106 		shmctl(id, IPC_RMID, NULL);
    107 		return 2;
    108 	}
    109 
    110 	/* wait for child1 to write to his segment */
    111 	TST_SAFE_CHECKPOINT_WAIT(NULL, 0);
    112 
    113 	*shmem = 'B';
    114 
    115 	TST_SAFE_CHECKPOINT_WAKE_AND_WAIT(NULL, 0);
    116 
    117 	shmdt(shmem);
    118 	shmctl(id, IPC_RMID, NULL);
    119 	return 0;
    120 }
    121 
    122 static void test(void)
    123 {
    124 	int status, ret = 0;
    125 
    126 	ret = do_clone_unshare_test(T_CLONE, CLONE_NEWIPC, chld1_shm, NULL);
    127 	if (ret == -1)
    128 		tst_brkm(TBROK | TERRNO, cleanup, "clone failed");
    129 
    130 	ret = do_clone_unshare_test(T_CLONE, CLONE_NEWIPC, chld2_shm, NULL);
    131 	if (ret == -1)
    132 		tst_brkm(TBROK | TERRNO, cleanup, "clone failed");
    133 
    134 
    135 	while (wait(&status) > 0) {
    136 		if (WIFEXITED(status) && WEXITSTATUS(status) == 1)
    137 			ret = 1;
    138 		if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
    139 			tst_brkm(TBROK | TERRNO, cleanup, "error in child");
    140 		if (WIFSIGNALED(status)) {
    141 			tst_resm(TFAIL, "child was killed with signal %s",
    142 					tst_strsig(WTERMSIG(status)));
    143 			return;
    144 		}
    145 	}
    146 
    147 	if (ret)
    148 		tst_resm(TFAIL, "SysV shm: communication with identical keys"
    149 				" between namespaces");
    150 	else
    151 		tst_resm(TPASS, "SysV shm: communication with identical keys"
    152 				" between namespaces");
    153 }
    154 
    155 int main(int argc, char *argv[])
    156 {
    157 	int lc;
    158 
    159 	tst_parse_opts(argc, argv, NULL, NULL);
    160 
    161 	setup();
    162 
    163 	for (lc = 0; TEST_LOOPING(lc); lc++)
    164 		test();
    165 
    166 	cleanup();
    167 	tst_exit();
    168 }
    169