lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library 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 the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; if not, write to the Free |
| 17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 18 | 02111-1307 USA. */ |
| 19 | |
| 20 | #include <errno.h> |
| 21 | #include <pthread.h> |
| 22 | #include <stdio.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <unistd.h> |
| 25 | #include <sys/file.h> |
| 26 | #include <sys/mman.h> |
| 27 | #include <sys/wait.h> |
| 28 | |
| 29 | |
| 30 | static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER; |
| 31 | static pthread_mutex_t lock2 = PTHREAD_MUTEX_INITIALIZER; |
| 32 | static int fd; |
| 33 | |
| 34 | |
| 35 | static void * |
| 36 | tf (void *arg) |
| 37 | { |
| 38 | struct flock fl = |
| 39 | { |
| 40 | .l_type = F_WRLCK, |
| 41 | .l_start = 0, |
| 42 | .l_whence = SEEK_SET, |
| 43 | .l_len = 10 |
| 44 | }; |
| 45 | if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0) |
| 46 | { |
| 47 | puts ("fourth fcntl failed"); |
| 48 | exit (1); |
| 49 | } |
| 50 | |
| 51 | pthread_mutex_unlock (&lock); |
| 52 | |
| 53 | pthread_mutex_lock (&lock2); |
| 54 | |
| 55 | return NULL; |
| 56 | } |
| 57 | |
| 58 | |
| 59 | static int |
| 60 | do_test (void) |
| 61 | { |
| 62 | char tmp[] = "/tmp/tst-flock2-XXXXXX"; |
| 63 | |
| 64 | fd = mkstemp (tmp); |
| 65 | if (fd == -1) |
| 66 | { |
| 67 | puts ("mkstemp failed"); |
| 68 | return 1; |
| 69 | } |
| 70 | |
| 71 | unlink (tmp); |
| 72 | |
| 73 | int i; |
| 74 | for (i = 0; i < 20; ++i) |
| 75 | write (fd, "foobar xyzzy", 12); |
| 76 | |
| 77 | pthread_barrier_t *b; |
| 78 | b = mmap (NULL, sizeof (pthread_barrier_t), PROT_READ | PROT_WRITE, |
| 79 | MAP_SHARED, fd, 0); |
| 80 | if (b == MAP_FAILED) |
| 81 | { |
| 82 | puts ("mmap failed"); |
| 83 | return 1; |
| 84 | } |
| 85 | |
| 86 | pthread_barrierattr_t ba; |
| 87 | if (pthread_barrierattr_init (&ba) != 0) |
| 88 | { |
| 89 | puts ("barrierattr_init failed"); |
| 90 | return 1; |
| 91 | } |
| 92 | |
| 93 | if (pthread_barrierattr_setpshared (&ba, PTHREAD_PROCESS_SHARED) != 0) |
| 94 | { |
| 95 | puts ("barrierattr_setpshared failed"); |
| 96 | return 1; |
| 97 | } |
| 98 | |
| 99 | if (pthread_barrier_init (b, &ba, 2) != 0) |
| 100 | { |
| 101 | puts ("barrier_init failed"); |
| 102 | return 1; |
| 103 | } |
| 104 | |
| 105 | if (pthread_barrierattr_destroy (&ba) != 0) |
| 106 | { |
| 107 | puts ("barrierattr_destroy failed"); |
| 108 | return 1; |
| 109 | } |
| 110 | |
| 111 | struct flock fl = |
| 112 | { |
| 113 | .l_type = F_WRLCK, |
| 114 | .l_start = 0, |
| 115 | .l_whence = SEEK_SET, |
| 116 | .l_len = 10 |
| 117 | }; |
| 118 | if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0) |
| 119 | { |
| 120 | puts ("first fcntl failed"); |
| 121 | return 1; |
| 122 | } |
| 123 | |
| 124 | pid_t pid = fork (); |
| 125 | if (pid == -1) |
| 126 | { |
| 127 | puts ("fork failed"); |
| 128 | return 1; |
| 129 | } |
| 130 | |
| 131 | if (pid == 0) |
| 132 | { |
| 133 | /* Make sure the child does not stay around indefinitely. */ |
| 134 | alarm (10); |
| 135 | |
| 136 | /* Try to get the lock. */ |
| 137 | if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0) |
| 138 | { |
| 139 | puts ("child: second flock succeeded"); |
| 140 | return 1; |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | pthread_barrier_wait (b); |
| 145 | |
| 146 | if (pid != 0) |
| 147 | { |
| 148 | fl.l_type = F_UNLCK; |
| 149 | if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0) |
| 150 | { |
| 151 | puts ("third fcntl failed"); |
| 152 | return 1; |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | pthread_barrier_wait (b); |
| 157 | |
| 158 | pthread_t th; |
| 159 | if (pid == 0) |
| 160 | { |
| 161 | if (pthread_mutex_lock (&lock) != 0) |
| 162 | { |
| 163 | puts ("1st locking of lock failed"); |
| 164 | return 1; |
| 165 | } |
| 166 | |
| 167 | if (pthread_mutex_lock (&lock2) != 0) |
| 168 | { |
| 169 | puts ("1st locking of lock2 failed"); |
| 170 | return 1; |
| 171 | } |
| 172 | |
| 173 | if (pthread_create (&th, NULL, tf, NULL) != 0) |
| 174 | { |
| 175 | puts ("pthread_create failed"); |
| 176 | return 1; |
| 177 | } |
| 178 | |
| 179 | if (pthread_mutex_lock (&lock) != 0) |
| 180 | { |
| 181 | puts ("2nd locking of lock failed"); |
| 182 | return 1; |
| 183 | } |
| 184 | |
| 185 | puts ("child locked file"); |
| 186 | } |
| 187 | |
| 188 | pthread_barrier_wait (b); |
| 189 | |
| 190 | if (pid != 0) |
| 191 | { |
| 192 | fl.l_type = F_WRLCK; |
| 193 | if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0) |
| 194 | { |
| 195 | puts ("fifth fcntl succeeded"); |
| 196 | return 1; |
| 197 | } |
| 198 | |
| 199 | puts ("file locked by child"); |
| 200 | } |
| 201 | |
| 202 | pthread_barrier_wait (b); |
| 203 | |
| 204 | if (pid == 0) |
| 205 | { |
| 206 | if (pthread_mutex_unlock (&lock2) != 0) |
| 207 | { |
| 208 | puts ("unlock of lock2 failed"); |
| 209 | return 1; |
| 210 | } |
| 211 | |
| 212 | if (pthread_join (th, NULL) != 0) |
| 213 | { |
| 214 | puts ("join failed"); |
| 215 | return 1; |
| 216 | } |
| 217 | |
| 218 | puts ("child's thread terminated"); |
| 219 | } |
| 220 | |
| 221 | pthread_barrier_wait (b); |
| 222 | |
| 223 | if (pid != 0) |
| 224 | { |
| 225 | fl.l_type = F_WRLCK; |
| 226 | if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0) |
| 227 | { |
| 228 | puts ("fifth fcntl succeeded"); |
| 229 | return 1; |
| 230 | } |
| 231 | |
| 232 | puts ("file still locked"); |
| 233 | } |
| 234 | |
| 235 | pthread_barrier_wait (b); |
| 236 | |
| 237 | if (pid == 0) |
| 238 | { |
| 239 | _exit (0); |
| 240 | } |
| 241 | |
| 242 | int status; |
| 243 | if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid) |
| 244 | { |
| 245 | puts ("waitpid failed"); |
| 246 | return 1; |
| 247 | } |
| 248 | puts ("child terminated"); |
| 249 | |
| 250 | if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0) |
| 251 | { |
| 252 | puts ("sixth fcntl failed"); |
| 253 | return 1; |
| 254 | } |
| 255 | |
| 256 | return status; |
| 257 | } |
| 258 | |
| 259 | #define TEST_FUNCTION do_test () |
| 260 | #include "../test-skeleton.c" |