nptl/tst-spin2.c

   1 /* Copyright (C) 2002-2019 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <pthread.h>
  21 #include <stdint.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <sys/mman.h>
  27 #include <sys/wait.h>
  28
  29
  30 static int
  31 do_test (void)
  32 {
  33   size_t ps = sysconf (_SC_PAGESIZE);
  34   char tmpfname[] = "/tmp/tst-spin2.XXXXXX";
  35   char data[ps];
  36   void *mem;
  37   int fd;
  38   pthread_spinlock_t *s;
  39   pid_t pid;
  40   char *p;
  41   int err;
  42
  43   fd = mkstemp (tmpfname);
  44   if (fd == -1)
  45     {
  46       printf ("cannot open temporary file: %m\n");
  47       return 1;
  48     }
  49
  50   /* Make sure it is always removed.  */
  51   unlink (tmpfname);
  52
  53   /* Create one page of data.  */
  54   memset (data, '\0', ps);
  55
  56   /* Write the data to the file.  */
  57   if (write (fd, data, ps) != (ssize_t) ps)
  58     {
  59       puts ("short write");
  60       return 1;
  61     }
  62
  63   mem = mmap (NULL, ps, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  64   if (mem == MAP_FAILED)
  65     {
  66       printf ("mmap failed: %m\n");
  67       return 1;
  68     }
  69
  70   s = (pthread_spinlock_t *) (((uintptr_t) mem
  71                                + __alignof (pthread_spinlock_t))
  72                               & ~(__alignof (pthread_spinlock_t) - 1));
  73   p = (char *) (s + 1);
  74
  75   if (pthread_spin_init (s, PTHREAD_PROCESS_SHARED) != 0)
  76     {
  77       puts ("spin_init failed");
  78       return 1;
  79     }
  80
  81   if (pthread_spin_lock (s) != 0)
  82     {
  83       puts ("spin_lock failed");
  84       return 1;
  85     }
  86
  87   err = pthread_spin_trylock (s);
  88   if (err == 0)
  89     {
  90       puts ("1st spin_trylock succeeded");
  91       return 1;
  92     }
  93   else if (err != EBUSY)
  94     {
  95       puts ("1st spin_trylock didn't return EBUSY");
  96       return 1;
  97     }
  98
  99   err = pthread_spin_unlock (s);
 100   if (err != 0)
 101     {
 102       puts ("parent: spin_unlock failed");
 103       return 1;
 104     }
 105
 106   err = pthread_spin_trylock (s);
 107   if (err != 0)
 108     {
 109       puts ("2nd spin_trylock failed");
 110       return 1;
 111     }
 112
 113   *p = 0;
 114
 115   puts ("going to fork now");
 116   pid = fork ();
 117   if (pid == -1)
 118     {
 119       puts ("fork failed");
 120       return 1;
 121     }
 122   else if (pid == 0)
 123     {
 124       /* Play some lock ping-pong.  It's our turn to unlock first.  */
 125       if ((*p)++ != 0)
 126         {
 127           puts ("child: *p != 0");
 128           return 1;
 129         }
 130
 131       if (pthread_spin_unlock (s) != 0)
 132         {
 133           puts ("child: 1st spin_unlock failed");
 134           return 1;
 135         }
 136
 137       puts ("child done");
 138     }
 139   else
 140     {
 141       if (pthread_spin_lock (s) != 0)
 142         {
 143           puts ("parent: 2nd spin_lock failed");
 144           return 1;
 145         }
 146
 147       puts ("waiting for child");
 148
 149       waitpid (pid, NULL, 0);
 150
 151       puts ("parent done");
 152     }
 153
 154   return 0;
 155 }
 156
 157 #define TEST_FUNCTION do_test ()
 158 #include "../test-skeleton.c"