nptl/tst-rwlock4.c

   1 /* Copyright (C) 2002 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 <stdint.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27 #include <sys/mman.h>
  28 #include <sys/wait.h>
  29
  30
  31 int
  32 main (void)
  33 {
  34   size_t ps = sysconf (_SC_PAGESIZE);
  35   char tmpfname[] = "/tmp/tst-rwlock4.XXXXXX";
  36   char data[ps];
  37   void *mem;
  38   int fd;
  39   pthread_rwlock_t *r;
  40   pthread_rwlockattr_t a;
  41   pid_t pid;
  42   char *p;
  43   int err;
  44   int s;
  45
  46   fd = mkstemp (tmpfname);
  47   if (fd == -1)
  48     {
  49       printf ("cannot open temporary file: %m\n");
  50       exit (1);
  51     }
  52
  53   /* Make sure it is always removed.  */
  54   unlink (tmpfname);
  55
  56   /* Create one page of data.  */
  57   memset (data, '\0', ps);
  58
  59   /* Write the data to the file.  */
  60   if (write (fd, data, ps) != ps)
  61     {
  62       puts ("short write");
  63       exit (1);
  64     }
  65
  66   mem = mmap (NULL, ps, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  67   if (mem == MAP_FAILED)
  68     {
  69       printf ("mmap failed: %m\n");
  70       exit (1);
  71     }
  72
  73   r = (pthread_rwlock_t *) (((uintptr_t) mem + __alignof (pthread_rwlock_t))
  74                             & ~(__alignof (pthread_rwlock_t) - 1));
  75   p = (char *) (r + 1);
  76
  77   if (pthread_rwlockattr_init (&a) != 0)
  78     {
  79       puts ("rwlockattr_init failed");
  80       exit (1);
  81     }
  82
  83   if (pthread_rwlockattr_getpshared (&a, &s) != 0)
  84     {
  85       puts ("1st rwlockattr_getpshared failed");
  86       exit (1);
  87     }
  88
  89   if (s != PTHREAD_PROCESS_PRIVATE)
  90     {
  91       puts ("default pshared value wrong");
  92       exit (1);
  93     }
  94
  95   if (pthread_rwlockattr_setpshared (&a, PTHREAD_PROCESS_SHARED) != 0)
  96     {
  97       puts ("rwlockattr_setpshared failed");
  98       exit (1);
  99     }
 100
 101   if (pthread_rwlockattr_getpshared (&a, &s) != 0)
 102     {
 103       puts ("2nd rwlockattr_getpshared failed");
 104       exit (1);
 105     }
 106
 107   if (s != PTHREAD_PROCESS_SHARED)
 108     {
 109       puts ("pshared value after setpshared call wrong");
 110       exit (1);
 111     }
 112
 113   if (pthread_rwlock_init (r, &a) != 0)
 114     {
 115       puts ("rwlock_init failed");
 116       exit (1);
 117     }
 118
 119   if (pthread_rwlock_rdlock (r) != 0)
 120     {
 121       puts ("rwlock_rdlock failed");
 122       exit (1);
 123     }
 124
 125   if (pthread_rwlockattr_destroy (&a) != 0)
 126     {
 127       puts ("rwlockattr_destroy failed");
 128       exit (1);
 129     }
 130
 131   err = pthread_rwlock_trywrlock (r);
 132   if (err == 0)
 133     {
 134       puts ("rwlock_trywrlock succeeded");
 135       exit (1);
 136     }
 137   else if (err != EBUSY)
 138     {
 139       puts ("rwlock_trywrlock didn't return EBUSY");
 140       exit (1);
 141     }
 142
 143   *p = 0;
 144
 145   puts ("going to fork now");
 146   pid = fork ();
 147   if (pid == -1)
 148     {
 149       puts ("fork failed");
 150       exit (1);
 151     }
 152   else if (pid == 0)
 153     {
 154       /* Play some lock ping-pong.  It's our turn to unlock first.  */
 155       if ((*p)++ != 0)
 156         {
 157           puts ("child: *p != 0");
 158           exit (1);
 159         }
 160
 161       if (pthread_rwlock_unlock (r) != 0)
 162         {
 163           puts ("child: 1st rwlock_unlock failed");
 164           exit (1);
 165         }
 166
 167       puts ("child done");
 168     }
 169   else
 170     {
 171       if (pthread_rwlock_wrlock (r) != 0)
 172         {
 173           puts ("parent: rwlock_wrlock failed");
 174           exit (1);
 175         }
 176
 177       if (*p != 1)
 178         {
 179           puts ("*p != 1");
 180           exit (1);
 181         }
 182
 183       puts ("parent done");
 184     }
 185
 186   exit (0);
 187 }