rt/tst-shm.c

   1 /* Test program for POSIX shm_* functions.
   2    Copyright (C) 2000-2020 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 2000.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <errno.h>
  21 #include <error.h>
  22 #include <fcntl.h>
  23 #include <signal.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <time.h>
  28 #include <unistd.h>
  29 #include <sys/mman.h>
  30 #include <sys/stat.h>
  31 #include <sys/wait.h>
  32
  33
  34 /* We want to see output immediately.  */
  35 #define STDOUT_UNBUFFERED
  36
  37 static void
  38 worker (int write_now)
  39 {
  40   struct timespec ts;
  41   struct stat64 st;
  42   int i;
  43   int fd = shm_open ("/glibc-shm-test", O_RDWR, 0600);
  44
  45   if (fd == -1)
  46     error (EXIT_FAILURE, 0, "failed to open shared memory object: shm_open");
  47
  48   char *mem;
  49
  50   if (fd == -1)
  51     exit (fd);
  52
  53   if (fstat64 (fd, &st) == -1)
  54     error (EXIT_FAILURE, 0, "stat failed");
  55   if (st.st_size != 4000)
  56     error (EXIT_FAILURE, 0, "size incorrect");
  57
  58   mem = mmap (NULL, 4000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  59   if (mem == MAP_FAILED)
  60     error (EXIT_FAILURE, 0, "mmap failed");
  61
  62   ts.tv_sec = 0;
  63   ts.tv_nsec = 500000000;
  64
  65   if (write_now)
  66     for (i = 0; i <= 4; ++i)
  67       mem[i] = i;
  68   else
  69     /* Wait until the first bytes of the memory region are 0, 1, 2, 3, 4.  */
  70     while (1)
  71       {
  72         for (i = 0; i <= 4; ++i)
  73           if (mem[i] != i)
  74             break;
  75
  76         if (i > 4)
  77           /* OK, that's done.  */
  78           break;
  79
  80         nanosleep (&ts, NULL);
  81       }
  82
  83   if (!write_now)
  84     for (i = 0; i <= 4; ++i)
  85       mem[i] = 4 + i;
  86   else
  87     /* Wait until the first bytes of the memory region are 4, 5, 6, 7, 8.  */
  88     while (1)
  89       {
  90         for (i = 0; i <= 4; ++i)
  91           if (mem[i] != 4 + i)
  92             break;
  93
  94         if (i > 4)
  95           /* OK, that's done.  */
  96           break;
  97
  98         nanosleep (&ts, NULL);
  99       }
 100
 101   if (munmap (mem, 4000) == -1)
 102     error (EXIT_FAILURE, errno, "munmap");
 103
 104   close (fd);
 105
 106   exit (0);
 107 }
 108
 109
 110 static int
 111 do_test (void)
 112 {
 113   int fd;
 114   pid_t pid1;
 115   pid_t pid2;
 116   int status1;
 117   int status2;
 118   struct stat64 st;
 119
 120   fd = shm_open ("/../escaped", O_RDWR | O_CREAT | O_TRUNC | O_EXCL, 0600);
 121   if (fd != -1)
 122     {
 123       perror ("read file outside of SHMDIR directory");
 124       return 1;
 125     }
 126
 127
 128   /* Create the shared memory object.  */
 129   fd = shm_open ("/glibc-shm-test", O_RDWR | O_CREAT | O_TRUNC | O_EXCL, 0600);
 130   if (fd == -1)
 131     {
 132       /* If shm_open is unimplemented we skip the test.  */
 133       if (errno == ENOSYS)
 134         {
 135           perror ("shm_open unimplemented.  Test skipped.");
 136           return 0;
 137         }
 138       else
 139         error (EXIT_FAILURE, 0, "failed to create shared memory object: shm_open");
 140     }
 141
 142   /* Size the object.  We make it 4000 bytes long.  */
 143   if (ftruncate (fd, 4000) == -1)
 144     {
 145       /* This failed.  Must be a bug in the implementation of the
 146          shared memory itself.  */
 147       perror ("failed to size of shared memory object: ftruncate");
 148       close (fd);
 149       shm_unlink ("/glibc-shm-test");
 150       return 0;
 151     }
 152
 153   if (fstat64 (fd, &st) == -1)
 154     {
 155       shm_unlink ("/glibc-shm-test");
 156       error (EXIT_FAILURE, 0, "initial stat failed");
 157     }
 158   if (st.st_size != 4000)
 159     {
 160       shm_unlink ("/glibc-shm-test");
 161       error (EXIT_FAILURE, 0, "initial size not correct");
 162     }
 163
 164   /* Spawn to processes which will do the work.  */
 165   pid1 = fork ();
 166   if (pid1 == 0)
 167     worker (0);
 168   else if (pid1 == -1)
 169     {
 170       /* Couldn't create a second process.  */
 171       perror ("fork");
 172       close (fd);
 173       shm_unlink ("/glibc-shm-test");
 174       return 0;
 175     }
 176
 177   pid2 = fork ();
 178   if (pid2 == 0)
 179     worker (1);
 180   else if (pid2 == -1)
 181     {
 182       /* Couldn't create a second process.  */
 183       int ignore;
 184       perror ("fork");
 185       kill (pid1, SIGTERM);
 186       waitpid (pid1, &ignore, 0);
 187       close (fd);
 188       shm_unlink ("/glibc-shm-test");
 189       return 0;
 190     }
 191
 192   /* Wait until the two processes are finished.  */
 193   waitpid (pid1, &status1, 0);
 194   waitpid (pid2, &status2, 0);
 195
 196   /* Now we can unlink the shared object.  */
 197   shm_unlink ("/glibc-shm-test");
 198
 199   return (!WIFEXITED (status1) || WEXITSTATUS (status1) != 0
 200           || !WIFEXITED (status2) || WEXITSTATUS (status2) != 0);
 201 }
 202
 203 static void
 204 cleanup_handler (void)
 205 {
 206   shm_unlink ("/glibc-shm-test");
 207 }
 208
 209 #define CLEANUP_HANDLER cleanup_handler
 210
 211 #include <support/test-driver.c>