nptl/tst-flock2.c

   1 /* Copyright (C) 2002-2017 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <pthread.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <sys/file.h>
  25 #include <sys/mman.h>
  26 #include <sys/wait.h>
  27
  28
  29 static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
  30 static pthread_mutex_t lock2 = PTHREAD_MUTEX_INITIALIZER;
  31 static int fd;
  32
  33
  34 static void *
  35 tf (void *arg)
  36 {
  37   struct flock fl =
  38     {
  39       .l_type = F_WRLCK,
  40       .l_start = 0,
  41       .l_whence = SEEK_SET,
  42       .l_len = 10
  43     };
  44   if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)
  45     {
  46       puts ("fourth fcntl failed");
  47       exit (1);
  48     }
  49
  50   pthread_mutex_unlock (&lock);
  51
  52   pthread_mutex_lock (&lock2);
  53
  54   return NULL;
  55 }
  56
  57
  58 static int
  59 do_test (void)
  60 {
  61   char tmp[] = "/tmp/tst-flock2-XXXXXX";
  62
  63   fd = mkstemp (tmp);
  64   if (fd == -1)
  65     {
  66       puts ("mkstemp failed");
  67       return 1;
  68     }
  69
  70   unlink (tmp);
  71
  72   int i;
  73   for (i = 0; i < 20; ++i)
  74     write (fd, "foobar xyzzy", 12);
  75
  76   pthread_barrier_t *b;
  77   b = mmap (NULL, sizeof (pthread_barrier_t), PROT_READ | PROT_WRITE,
  78             MAP_SHARED, fd, 0);
  79   if (b == MAP_FAILED)
  80     {
  81       puts ("mmap failed");
  82       return 1;
  83     }
  84
  85   pthread_barrierattr_t ba;
  86   if (pthread_barrierattr_init (&ba) != 0)
  87     {
  88       puts ("barrierattr_init failed");
  89       return 1;
  90     }
  91
  92   if (pthread_barrierattr_setpshared (&ba, PTHREAD_PROCESS_SHARED) != 0)
  93     {
  94       puts ("barrierattr_setpshared failed");
  95       return 1;
  96     }
  97
  98   if (pthread_barrier_init (b, &ba, 2) != 0)
  99     {
 100       puts ("barrier_init failed");
 101       return 1;
 102     }
 103
 104   if (pthread_barrierattr_destroy (&ba) != 0)
 105     {
 106       puts ("barrierattr_destroy failed");
 107       return 1;
 108     }
 109
 110   struct flock fl =
 111     {
 112       .l_type = F_WRLCK,
 113       .l_start = 0,
 114       .l_whence = SEEK_SET,
 115       .l_len = 10
 116     };
 117   if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)
 118     {
 119       puts ("first fcntl failed");
 120       return 1;
 121     }
 122
 123   pid_t pid = fork ();
 124   if (pid == -1)
 125     {
 126       puts ("fork failed");
 127       return 1;
 128     }
 129
 130   if (pid == 0)
 131     {
 132       /* Make sure the child does not stay around indefinitely.  */
 133       alarm (10);
 134
 135       /* Try to get the lock.  */
 136       if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0)
 137         {
 138           puts ("child:  second flock succeeded");
 139           return 1;
 140         }
 141     }
 142
 143   pthread_barrier_wait (b);
 144
 145   if (pid != 0)
 146     {
 147       fl.l_type = F_UNLCK;
 148       if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)
 149         {
 150           puts ("third fcntl failed");
 151           return 1;
 152         }
 153     }
 154
 155   pthread_barrier_wait (b);
 156
 157   pthread_t th;
 158   if (pid == 0)
 159     {
 160       if (pthread_mutex_lock (&lock) != 0)
 161         {
 162           puts ("1st locking of lock failed");
 163           return 1;
 164         }
 165
 166       if (pthread_mutex_lock (&lock2) != 0)
 167         {
 168           puts ("1st locking of lock2 failed");
 169           return 1;
 170         }
 171
 172       if (pthread_create (&th, NULL, tf, NULL) != 0)
 173         {
 174           puts ("pthread_create failed");
 175           return 1;
 176         }
 177
 178       if (pthread_mutex_lock (&lock) != 0)
 179         {
 180           puts ("2nd locking of lock failed");
 181           return 1;
 182         }
 183
 184       puts ("child locked file");
 185     }
 186
 187   pthread_barrier_wait (b);
 188
 189   if (pid != 0)
 190     {
 191       fl.l_type = F_WRLCK;
 192       if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0)
 193         {
 194           puts ("fifth fcntl succeeded");
 195           return 1;
 196         }
 197
 198       puts ("file locked by child");
 199     }
 200
 201   pthread_barrier_wait (b);
 202
 203   if (pid == 0)
 204     {
 205       if (pthread_mutex_unlock (&lock2) != 0)
 206         {
 207           puts ("unlock of lock2 failed");
 208           return 1;
 209         }
 210
 211       if (pthread_join (th, NULL) != 0)
 212         {
 213           puts ("join failed");
 214           return 1;
 215         }
 216
 217       puts ("child's thread terminated");
 218     }
 219
 220   pthread_barrier_wait (b);
 221
 222   if (pid != 0)
 223     {
 224       fl.l_type = F_WRLCK;
 225       if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLK, &fl)) == 0)
 226         {
 227           puts ("fifth fcntl succeeded");
 228           return 1;
 229         }
 230
 231       puts ("file still locked");
 232     }
 233
 234   pthread_barrier_wait (b);
 235
 236   if (pid == 0)
 237     {
 238       _exit (0);
 239     }
 240
 241   int status;
 242   if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)
 243     {
 244       puts ("waitpid failed");
 245       return 1;
 246     }
 247   puts ("child terminated");
 248
 249   if (TEMP_FAILURE_RETRY (fcntl (fd, F_SETLKW, &fl)) != 0)
 250     {
 251       puts ("sixth fcntl failed");
 252       return 1;
 253     }
 254
 255   return status;
 256 }
 257
 258 #define TEST_FUNCTION do_test ()
 259 #include "../test-skeleton.c"