104 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			104 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
| // SPDX-License-Identifier: GPL-2.0-or-later
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| /*
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|  * Copyright (c) 2014 Fujitsu Ltd.
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|  * Author: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
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|  */
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| 
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| /*
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|  * Note: this test has already been in xfstests generic/028 test case,
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|  * I just port it to LTP.
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|  *
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|  * Kernel commit '232d2d60aa5469bb097f55728f65146bd49c1d25' introduced a race
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|  * condition that causes getcwd(2) to return "/" instead of correct path.
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|  *     232d2d6 dcache: Translating dentry into pathname without
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|  *             taking rename_lock
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|  *
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|  * And these two kernel commits fixed the bug:
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|  *   ede4cebce16f5643c61aedd6d88d9070a1d23a68
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|  *	prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts
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|  *   f6500801522c61782d4990fa1ad96154cb397cd4
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|  *	f650080 __dentry_path() fixes
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|  *
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|  * This test is to check whether this bug exists in the running kernel,
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|  * or whether this bug has been fixed.
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|  */
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| 
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| #include <stdio.h>
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| #include <errno.h>
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| #include <fcntl.h>
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| #include <sys/types.h>
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| #include <unistd.h>
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| #include "tst_test.h"
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| 
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| #define TIMEOUT	5
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| 
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| static void do_child(void);
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| static void sigproc(int sig);
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| static volatile sig_atomic_t end;
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| static char init_cwd[PATH_MAX];
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| 
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| static void verify_getcwd(void)
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| {
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| 	int status;
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| 	char cur_cwd[PATH_MAX];
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| 	pid_t child;
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| 
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| 	child = SAFE_FORK();
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| 	if (child == 0)
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| 		do_child();
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| 
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| 	 while (1) {
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| 		SAFE_GETCWD(cur_cwd, PATH_MAX);
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| 		if (strncmp(init_cwd, cur_cwd, PATH_MAX)) {
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| 			tst_res(TFAIL, "initial current work directory is "
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| 				 "%s, now is %s. Bug is reproduced!",
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| 				 init_cwd, cur_cwd);
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| 			break;
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| 		}
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| 
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| 		if (end) {
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| 			tst_res(TPASS, "Bug is not reproduced!");
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| 			break;
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| 		}
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| 	}
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| 
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| 	SAFE_KILL(child, SIGKILL);
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| 	SAFE_WAITPID(child, &status, 0);
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| }
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| 
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| static void setup(void)
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| {
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| 	SAFE_SIGNAL(SIGALRM, sigproc);
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| 
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| 	alarm(TIMEOUT);
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| 
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| 	SAFE_GETCWD(init_cwd, PATH_MAX);
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| }
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| 
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| static void sigproc(int sig)
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| {
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| 	end = sig;
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| }
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| 
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| static void do_child(void)
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| {
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| 	unsigned int i = 0;
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| 	char c_name[PATH_MAX] = "testfile", n_name[PATH_MAX];
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| 
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| 	SAFE_TOUCH(c_name, 0644, NULL);
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| 
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| 	while (1) {
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| 		snprintf(n_name, PATH_MAX, "testfile%u", i++);
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| 		SAFE_RENAME(c_name, n_name);
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| 		strncpy(c_name, n_name, PATH_MAX);
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| 	}
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| }
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| 
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| static struct tst_test test = {
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| 	.setup = setup,
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| 	.test_all = verify_getcwd,
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| 	.needs_tmpdir = 1,
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| 	.forks_child = 1,
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| 	.min_cpus = 2
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| };
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