rt/tst-shm.c

   1 /* Test program for POSIX shm_* functions.
   2    Copyright (C) 2000-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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 <error.h>
  21 #include <fcntl.h>
  22 #include <signal.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <time.h>
  27 #include <unistd.h>
  28 #include <sys/mman.h>
  29 #include <sys/stat.h>
  30 #include <sys/wait.h>
  31
  32
  33 /* We want to see output immediately.  */
  34 #define STDOUT_UNBUFFERED
  35
  36 static char shm_test_name[sizeof "/glibc-shm-test-" + sizeof (pid_t) * 3];
  37 static char shm_escape_name[sizeof "/../escaped-" + sizeof (pid_t) * 3];
  38
  39 static void
  40 init_shm_test_names (void)
  41 {
  42   snprintf (shm_test_name, sizeof (shm_test_name), "/glibc-shm-test-%u",
  43             getpid ());
  44   snprintf (shm_escape_name, sizeof (shm_escape_name), "/../escaped-%u",
  45             getpid ());
  46 }
  47
  48 static void
  49 worker (int write_now)
  50 {
  51   struct timespec ts;
  52   struct stat64 st;
  53   int i;
  54
  55   int fd = shm_open (shm_test_name, O_RDWR, 0600);
  56
  57   if (fd == -1)
  58     error (EXIT_FAILURE, 0, "failed to open shared memory object: shm_open");
  59
  60   char *mem;
  61
  62   if (fd == -1)
  63     exit (fd);
  64
  65   if (fstat64 (fd, &st) == -1)
  66     error (EXIT_FAILURE, 0, "stat failed");
  67   if (st.st_size != 4000)
  68     error (EXIT_FAILURE, 0, "size incorrect");
  69
  70   mem = mmap (NULL, 4000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  71   if (mem == MAP_FAILED)
  72     error (EXIT_FAILURE, 0, "mmap failed");
  73
  74   ts.tv_sec = 0;
  75   ts.tv_nsec = 500000000;
  76
  77   if (write_now)
  78     for (i = 0; i <= 4; ++i)
  79       mem[i] = i;
  80   else
  81     /* Wait until the first bytes of the memory region are 0, 1, 2, 3, 4.  */
  82     while (1)
  83       {
  84         for (i = 0; i <= 4; ++i)
  85           if (mem[i] != i)
  86             break;
  87
  88         if (i > 4)
  89           /* OK, that's done.  */
  90           break;
  91
  92         nanosleep (&ts, NULL);
  93       }
  94
  95   if (!write_now)
  96     for (i = 0; i <= 4; ++i)
  97       mem[i] = 4 + i;
  98   else
  99     /* Wait until the first bytes of the memory region are 4, 5, 6, 7, 8.  */
 100     while (1)
 101       {
 102         for (i = 0; i <= 4; ++i)
 103           if (mem[i] != 4 + i)
 104             break;
 105
 106         if (i > 4)
 107           /* OK, that's done.  */
 108           break;
 109
 110         nanosleep (&ts, NULL);
 111       }
 112
 113   if (munmap (mem, 4000) == -1)
 114     error (EXIT_FAILURE, errno, "munmap");
 115
 116   close (fd);
 117
 118   exit (0);
 119 }
 120
 121
 122 static int
 123 do_test (void)
 124 {
 125   int fd;
 126   pid_t pid1;
 127   pid_t pid2;
 128   int status1;
 129   int status2;
 130   struct stat64 st;
 131
 132   init_shm_test_names ();
 133
 134   fd = shm_open (shm_escape_name, O_RDWR | O_CREAT | O_TRUNC | O_EXCL, 0600);
 135   if (fd != -1)
 136     {
 137       perror ("read file outside of SHMDIR directory");
 138       return 1;
 139     }
 140
 141
 142   /* Create the shared memory object.  */
 143   fd = shm_open (shm_test_name, O_RDWR | O_CREAT | O_TRUNC | O_EXCL, 0600);
 144   if (fd == -1)
 145     {
 146       /* If shm_open is unimplemented we skip the test.  */
 147       if (errno == ENOSYS)
 148         {
 149           perror ("shm_open unimplemented.  Test skipped.");
 150           return 0;
 151         }
 152       else
 153         error (EXIT_FAILURE, 0, "failed to create shared memory object: shm_open");
 154     }
 155
 156   /* Size the object.  We make it 4000 bytes long.  */
 157   if (ftruncate (fd, 4000) == -1)
 158     {
 159       /* This failed.  Must be a bug in the implementation of the
 160          shared memory itself.  */
 161       perror ("failed to size of shared memory object: ftruncate");
 162       close (fd);
 163       shm_unlink (shm_test_name);
 164       return 0;
 165     }
 166
 167   if (fstat64 (fd, &st) == -1)
 168     {
 169       shm_unlink (shm_test_name);
 170       error (EXIT_FAILURE, 0, "initial stat failed");
 171     }
 172   if (st.st_size != 4000)
 173     {
 174       shm_unlink (shm_test_name);
 175       error (EXIT_FAILURE, 0, "initial size not correct");
 176     }
 177
 178   /* Spawn to processes which will do the work.  */
 179   pid1 = fork ();
 180   if (pid1 == 0)
 181     worker (0);
 182   else if (pid1 == -1)
 183     {
 184       /* Couldn't create a second process.  */
 185       perror ("fork");
 186       close (fd);
 187       shm_unlink (shm_test_name);
 188       return 0;
 189     }
 190
 191   pid2 = fork ();
 192   if (pid2 == 0)
 193     worker (1);
 194   else if (pid2 == -1)
 195     {
 196       /* Couldn't create a second process.  */
 197       int ignore;
 198       perror ("fork");
 199       kill (pid1, SIGTERM);
 200       waitpid (pid1, &ignore, 0);
 201       close (fd);
 202       shm_unlink (shm_test_name);
 203       return 0;
 204     }
 205
 206   /* Wait until the two processes are finished.  */
 207   waitpid (pid1, &status1, 0);
 208   waitpid (pid2, &status2, 0);
 209
 210   /* Now we can unlink the shared object.  */
 211   shm_unlink (shm_test_name);
 212
 213   return (!WIFEXITED (status1) || WEXITSTATUS (status1) != 0
 214           || !WIFEXITED (status2) || WEXITSTATUS (status2) != 0);
 215 }
 216
 217 static void
 218 cleanup_handler (void)
 219 {
 220   shm_unlink (shm_test_name);
 221 }
 222
 223 #define CLEANUP_HANDLER cleanup_handler
 224
 225 #include <support/test-driver.c>