rt/tst-shm.c

   1 /* Test program for POSIX shm_* functions.
   2    Copyright (C) 2000-2021 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 char shm_test_name[sizeof "/glibc-shm-test-" + sizeof (pid_t) * 3];
  38 static char shm_escape_name[sizeof "/../escaped-" + sizeof (pid_t) * 3];
  39
  40 static void
  41 init_shm_test_names (void)
  42 {
  43   snprintf (shm_test_name, sizeof (shm_test_name), "/glibc-shm-test-%u",
  44             getpid ());
  45   snprintf (shm_escape_name, sizeof (shm_escape_name), "/../escaped-%u",
  46             getpid ());
  47 }
  48
  49 static void
  50 worker (int write_now)
  51 {
  52   struct timespec ts;
  53   struct stat64 st;
  54   int i;
  55
  56   int fd = shm_open (shm_test_name, O_RDWR, 0600);
  57
  58   if (fd == -1)
  59     error (EXIT_FAILURE, 0, "failed to open shared memory object: shm_open");
  60
  61   char *mem;
  62
  63   if (fd == -1)
  64     exit (fd);
  65
  66   if (fstat64 (fd, &st) == -1)
  67     error (EXIT_FAILURE, 0, "stat failed");
  68   if (st.st_size != 4000)
  69     error (EXIT_FAILURE, 0, "size incorrect");
  70
  71   mem = mmap (NULL, 4000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  72   if (mem == MAP_FAILED)
  73     error (EXIT_FAILURE, 0, "mmap failed");
  74
  75   ts.tv_sec = 0;
  76   ts.tv_nsec = 500000000;
  77
  78   if (write_now)
  79     for (i = 0; i <= 4; ++i)
  80       mem[i] = i;
  81   else
  82     /* Wait until the first bytes of the memory region are 0, 1, 2, 3, 4.  */
  83     while (1)
  84       {
  85         for (i = 0; i <= 4; ++i)
  86           if (mem[i] != i)
  87             break;
  88
  89         if (i > 4)
  90           /* OK, that's done.  */
  91           break;
  92
  93         nanosleep (&ts, NULL);
  94       }
  95
  96   if (!write_now)
  97     for (i = 0; i <= 4; ++i)
  98       mem[i] = 4 + i;
  99   else
 100     /* Wait until the first bytes of the memory region are 4, 5, 6, 7, 8.  */
 101     while (1)
 102       {
 103         for (i = 0; i <= 4; ++i)
 104           if (mem[i] != 4 + i)
 105             break;
 106
 107         if (i > 4)
 108           /* OK, that's done.  */
 109           break;
 110
 111         nanosleep (&ts, NULL);
 112       }
 113
 114   if (munmap (mem, 4000) == -1)
 115     error (EXIT_FAILURE, errno, "munmap");
 116
 117   close (fd);
 118
 119   exit (0);
 120 }
 121
 122
 123 static int
 124 do_test (void)
 125 {
 126   int fd;
 127   pid_t pid1;
 128   pid_t pid2;
 129   int status1;
 130   int status2;
 131   struct stat64 st;
 132
 133   init_shm_test_names ();
 134
 135   fd = shm_open (shm_escape_name, O_RDWR | O_CREAT | O_TRUNC | O_EXCL, 0600);
 136   if (fd != -1)
 137     {
 138       perror ("read file outside of SHMDIR directory");
 139       return 1;
 140     }
 141
 142
 143   /* Create the shared memory object.  */
 144   fd = shm_open (shm_test_name, O_RDWR | O_CREAT | O_TRUNC | O_EXCL, 0600);
 145   if (fd == -1)
 146     {
 147       /* If shm_open is unimplemented we skip the test.  */
 148       if (errno == ENOSYS)
 149         {
 150           perror ("shm_open unimplemented.  Test skipped.");
 151           return 0;
 152         }
 153       else
 154         error (EXIT_FAILURE, 0, "failed to create shared memory object: shm_open");
 155     }
 156
 157   /* Size the object.  We make it 4000 bytes long.  */
 158   if (ftruncate (fd, 4000) == -1)
 159     {
 160       /* This failed.  Must be a bug in the implementation of the
 161          shared memory itself.  */
 162       perror ("failed to size of shared memory object: ftruncate");
 163       close (fd);
 164       shm_unlink (shm_test_name);
 165       return 0;
 166     }
 167
 168   if (fstat64 (fd, &st) == -1)
 169     {
 170       shm_unlink (shm_test_name);
 171       error (EXIT_FAILURE, 0, "initial stat failed");
 172     }
 173   if (st.st_size != 4000)
 174     {
 175       shm_unlink (shm_test_name);
 176       error (EXIT_FAILURE, 0, "initial size not correct");
 177     }
 178
 179   /* Spawn to processes which will do the work.  */
 180   pid1 = fork ();
 181   if (pid1 == 0)
 182     worker (0);
 183   else if (pid1 == -1)
 184     {
 185       /* Couldn't create a second process.  */
 186       perror ("fork");
 187       close (fd);
 188       shm_unlink (shm_test_name);
 189       return 0;
 190     }
 191
 192   pid2 = fork ();
 193   if (pid2 == 0)
 194     worker (1);
 195   else if (pid2 == -1)
 196     {
 197       /* Couldn't create a second process.  */
 198       int ignore;
 199       perror ("fork");
 200       kill (pid1, SIGTERM);
 201       waitpid (pid1, &ignore, 0);
 202       close (fd);
 203       shm_unlink (shm_test_name);
 204       return 0;
 205     }
 206
 207   /* Wait until the two processes are finished.  */
 208   waitpid (pid1, &status1, 0);
 209   waitpid (pid2, &status2, 0);
 210
 211   /* Now we can unlink the shared object.  */
 212   shm_unlink (shm_test_name);
 213
 214   return (!WIFEXITED (status1) || WEXITSTATUS (status1) != 0
 215           || !WIFEXITED (status2) || WEXITSTATUS (status2) != 0);
 216 }
 217
 218 static void
 219 cleanup_handler (void)
 220 {
 221   shm_unlink (shm_test_name);
 222 }
 223
 224 #define CLEANUP_HANDLER cleanup_handler
 225
 226 #include <support/test-driver.c>