sysdeps/pthread/tst-rwlock4.c

   1 /* Copyright (C) 2002-2024 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-rwlock4.XXXXXX";
  34   char data[ps];
  35   void *mem;
  36   int fd;
  37   pthread_rwlock_t *r;
  38   pthread_rwlockattr_t a;
  39   pid_t pid;
  40   char *p;
  41   int err;
  42   int s;
  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   p = (char *) (r + 1);
  74
  75   if (pthread_rwlockattr_init (&a) != 0)
  76     {
  77       puts ("rwlockattr_init failed");
  78       return 1;
  79     }
  80
  81   if (pthread_rwlockattr_getpshared (&a, &s) != 0)
  82     {
  83       puts ("1st rwlockattr_getpshared failed");
  84       return 1;
  85     }
  86
  87   if (s != PTHREAD_PROCESS_PRIVATE)
  88     {
  89       puts ("default pshared value wrong");
  90       return 1;
  91     }
  92
  93   if (pthread_rwlockattr_setpshared (&a, PTHREAD_PROCESS_SHARED) != 0)
  94     {
  95       puts ("rwlockattr_setpshared failed");
  96       return 1;
  97     }
  98
  99   if (pthread_rwlockattr_getpshared (&a, &s) != 0)
 100     {
 101       puts ("2nd rwlockattr_getpshared failed");
 102       return 1;
 103     }
 104
 105   if (s != PTHREAD_PROCESS_SHARED)
 106     {
 107       puts ("pshared value after setpshared call wrong");
 108       return 1;
 109     }
 110
 111   if (pthread_rwlock_init (r, &a) != 0)
 112     {
 113       puts ("rwlock_init failed");
 114       return 1;
 115     }
 116
 117   if (pthread_rwlock_rdlock (r) != 0)
 118     {
 119       puts ("rwlock_rdlock failed");
 120       return 1;
 121     }
 122
 123   if (pthread_rwlockattr_destroy (&a) != 0)
 124     {
 125       puts ("rwlockattr_destroy failed");
 126       return 1;
 127     }
 128
 129   err = pthread_rwlock_trywrlock (r);
 130   if (err == 0)
 131     {
 132       puts ("rwlock_trywrlock succeeded");
 133       return 1;
 134     }
 135   else if (err != EBUSY)
 136     {
 137       puts ("rwlock_trywrlock didn't return EBUSY");
 138       return 1;
 139     }
 140
 141   *p = 0;
 142
 143   puts ("going to fork now");
 144   pid = fork ();
 145   if (pid == -1)
 146     {
 147       puts ("fork failed");
 148       return 1;
 149     }
 150   else if (pid == 0)
 151     {
 152       /* Play some lock ping-pong.  It's our turn to unlock first.  */
 153       if ((*p)++ != 0)
 154         {
 155           puts ("child: *p != 0");
 156           return 1;
 157         }
 158
 159       if (pthread_rwlock_unlock (r) != 0)
 160         {
 161           puts ("child: 1st rwlock_unlock failed");
 162           return 1;
 163         }
 164
 165       puts ("child done");
 166     }
 167   else
 168     {
 169       if (pthread_rwlock_wrlock (r) != 0)
 170         {
 171           puts ("parent: rwlock_wrlock failed");
 172           return 1;
 173         }
 174
 175       if (*p != 1)
 176         {
 177           puts ("*p != 1");
 178           return 1;
 179         }
 180
 181       puts ("parent done");
 182     }
 183
 184   return 0;
 185 }
 186
 187 #define TEST_FUNCTION do_test ()
 188 #include "../test-skeleton.c"