1 /*
2 * Copyright (c) 2014 Fujitsu Ltd.
3 * Author: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 */
15
16 /*
17 * Note: this test has already been in xfstests generic/028 test case,
18 * I just port it to LTP.
19 *
20 * Kernel commit '232d2d60aa5469bb097f55728f65146bd49c1d25' introduced a race
21 * condition that causes getcwd(2) to return "/" instead of correct path.
22 * 232d2d6 dcache: Translating dentry into pathname without
23 * taking rename_lock
24 *
25 * And these two kernel commits fixed the bug:
26 * ede4cebce16f5643c61aedd6d88d9070a1d23a68
27 * prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts
28 * f6500801522c61782d4990fa1ad96154cb397cd4
29 * f650080 __dentry_path() fixes
30 *
31 * This test is to check whether this bug exists in the running kernel,
32 * or whether this bug has been fixed.
33 *
34 */
35
36 #include <stdio.h>
37 #include <errno.h>
38 #include <fcntl.h>
39 #include <sys/types.h>
40 #include <unistd.h>
41 #include "test.h"
42 #include "safe_macros.h"
43
44 #define TIMEOUT 5
45
46 static void setup(void);
47 static void cleanup(void);
48 static void do_child(void);
49 static void sigproc(int sig);
50 static volatile sig_atomic_t end;
51 static char init_cwd[PATH_MAX];
52
53 char *TCID = "getcwd04";
54 int TST_TOTAL = 1;
55
main(int ac,char ** av)56 int main(int ac, char **av)
57 {
58 int status;
59 char cur_cwd[PATH_MAX];
60 pid_t child;
61
62 tst_parse_opts(ac, av, NULL, NULL);
63
64 setup();
65
66 child = tst_fork();
67 if (child < 0)
68 tst_brkm(TBROK | TERRNO, cleanup, "fork failed");
69
70 if (child == 0)
71 do_child();
72
73 while (1) {
74 SAFE_GETCWD(cleanup, cur_cwd, PATH_MAX);
75 if (strncmp(init_cwd, cur_cwd, PATH_MAX)) {
76 tst_resm(TFAIL, "initial current work directory is "
77 "%s, now is %s. Bug is reproduced!",
78 init_cwd, cur_cwd);
79 break;
80 }
81
82 if (end) {
83 tst_resm(TPASS, "Bug is not reproduced!");
84 break;
85 }
86 }
87
88 SAFE_KILL(cleanup, child, SIGKILL);
89 SAFE_WAITPID(cleanup, child, &status, 0);
90
91 cleanup();
92 tst_exit();
93 }
94
setup(void)95 static void setup(void)
96 {
97 tst_sig(FORK, DEF_HANDLER, cleanup);
98
99 TEST_PAUSE;
100
101 if (tst_ncpus() == 1)
102 tst_brkm(TCONF, NULL, "This test needs two cpus at least");
103
104 tst_tmpdir();
105
106 if (signal(SIGALRM, sigproc) == SIG_ERR)
107 tst_brkm(TBROK | TERRNO, cleanup, "signal(SIGALRM) failed");
108
109 alarm(TIMEOUT);
110
111 SAFE_GETCWD(cleanup, init_cwd, PATH_MAX);
112 }
113
sigproc(int sig)114 static void sigproc(int sig)
115 {
116 end = sig;
117 }
118
do_child(void)119 static void do_child(void)
120 {
121 unsigned int i = 0;
122 char c_name[PATH_MAX] = "testfile", n_name[PATH_MAX];
123
124 SAFE_TOUCH(NULL, c_name, 0644, NULL);
125
126 while (1) {
127 snprintf(n_name, PATH_MAX, "testfile%u", i++);
128 SAFE_RENAME(NULL, c_name, n_name);
129 strncpy(c_name, n_name, PATH_MAX);
130 }
131 }
132
cleanup(void)133 static void cleanup(void)
134 {
135 tst_rmdir();
136 }
137