sysdeps/pthread/tst-rwlock12.c

   1 /* Copyright (C) 2002-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <pthread.h>
  20 #include <stdint.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <sys/mman.h>
  26 #include <sys/wait.h>
  27
  28
  29 static int
  30 do_test (void)
  31 {
  32   size_t ps = sysconf (_SC_PAGESIZE);
  33   char tmpfname[] = "/tmp/tst-rwlock12.XXXXXX";
  34   char data[ps];
  35   void *mem;
  36   int fd;
  37   pthread_mutex_t *m;
  38   pthread_mutexattr_t ma;
  39   pthread_rwlock_t *r;
  40   pthread_rwlockattr_t ra;
  41   pid_t pid;
  42   int status = 0;
  43
  44   fd = mkstemp (tmpfname);
  45   if (fd == -1)
  46     {
  47       printf ("cannot open temporary file: %m\n");
  48       return 1;
  49     }
  50
  51   /* Make sure it is always removed.  */
  52   unlink (tmpfname);
  53
  54   /* Create one page of data.  */
  55   memset (data, '\0', ps);
  56
  57   /* Write the data to the file.  */
  58   if (write (fd, data, ps) != (ssize_t) ps)
  59     {
  60       puts ("short write");
  61       return 1;
  62     }
  63
  64   mem = mmap (NULL, ps, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  65   if (mem == MAP_FAILED)
  66     {
  67       printf ("mmap failed: %m\n");
  68       return 1;
  69     }
  70
  71   r = (pthread_rwlock_t *) (((uintptr_t) mem + __alignof (pthread_rwlock_t))
  72                             & ~(__alignof (pthread_rwlock_t) - 1));
  73   /* The following assumes alignment for a mutex is at least as high
  74      as that for a rwlock.  Which is true in our case.  */
  75   m = (pthread_mutex_t *) (r + 1);
  76
  77   if (pthread_rwlockattr_init (&ra) != 0)
  78     {
  79       puts ("rwlockattr_init failed");
  80       return 1;
  81     }
  82
  83   if (pthread_rwlockattr_setpshared (&ra, PTHREAD_PROCESS_SHARED) != 0)
  84     {
  85       puts ("rwlockattr_setpshared failed");
  86       return 1;
  87     }
  88
  89   if (pthread_rwlock_init (r, &ra) != 0)
  90     {
  91       puts ("rwlock_init failed");
  92       return 1;
  93     }
  94
  95   if (pthread_mutexattr_init (&ma) != 0)
  96     {
  97       puts ("rwlockattr_init failed");
  98       return 1;
  99     }
 100
 101   if (pthread_mutexattr_setpshared (&ma, PTHREAD_PROCESS_SHARED) != 0)
 102     {
 103       puts ("mutexattr_setpshared failed");
 104       return 1;
 105     }
 106
 107   if (pthread_mutex_init (m, &ma) != 0)
 108     {
 109       puts ("mutex_init failed");
 110       return 1;
 111     }
 112
 113   /* Lock the mutex.  */
 114   if (pthread_mutex_lock (m) != 0)
 115     {
 116       puts ("mutex_lock failed");
 117       return 1;
 118     }
 119
 120   puts ("going to fork now");
 121   pid = fork ();
 122   if (pid == -1)
 123     {
 124       puts ("fork failed");
 125       return 1;
 126     }
 127   else if (pid == 0)
 128     {
 129       /* Lock the mutex.  */
 130       if (pthread_mutex_lock (m) != 0)
 131         {
 132           puts ("child: mutex_lock failed");
 133           return 1;
 134         }
 135
 136       /* Try to get the rwlock.  */
 137       if (pthread_rwlock_trywrlock (r) == 0)
 138         {
 139           puts ("rwlock_trywrlock succeeded");
 140           return 1;
 141         }
 142
 143       /* Try again.  */
 144       struct timespec ts = { .tv_sec = 0, .tv_nsec = 500000000 };
 145       int e = pthread_rwlock_timedwrlock (r, &ts);
 146       if (e == 0)
 147         {
 148           puts ("rwlock_timedwrlock succeeded");
 149           return 1;
 150         }
 151       if (e != ETIMEDOUT)
 152         {
 153           puts ("rwlock_timedwrlock didn't return ETIMEDOUT");
 154           status = 1;
 155         }
 156
 157       if (pthread_rwlock_tryrdlock (r) == 0)
 158         {
 159           puts ("rwlock_tryrdlock succeeded");
 160           return 1;
 161         }
 162
 163       e = pthread_rwlock_timedrdlock (r, &ts);
 164       if (e == 0)
 165         {
 166           puts ("rwlock_timedrdlock succeeded");
 167           return 1;
 168         }
 169       if (e != ETIMEDOUT)
 170         {
 171           puts ("rwlock_timedrdlock didn't return ETIMEDOUT");
 172           status = 1;
 173         }
 174     }
 175   else
 176     {
 177       /* Lock the rwlock for writing.  */
 178       if (pthread_rwlock_wrlock (r) != 0)
 179         {
 180           puts ("rwlock_wrlock failed");
 181           kill (pid, SIGTERM);
 182           return 1;
 183         }
 184
 185       /* Allow the child to run.  */
 186       if (pthread_mutex_unlock (m) != 0)
 187         {
 188           puts ("mutex_unlock failed");
 189           kill (pid, SIGTERM);
 190           return 1;
 191         }
 192
 193       /* Just wait for the child.  */
 194       if (TEMP_FAILURE_RETRY (waitpid (pid, &status, 0)) != pid)
 195         {
 196           puts ("waitpid failed");
 197           kill (pid, SIGTERM);
 198           return 1;
 199         }
 200     }
 201
 202   return status;
 203 }
 204
 205 #define TEST_FUNCTION do_test ()
 206 #include "../test-skeleton.c"