tests/test-exit-with-parent.c

   1 /* nbdkit
   2  * Copyright (C) 2017 Red Hat Inc.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <config.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <stdint.h>
  38 #include <inttypes.h>
  39 #include <string.h>
  40 #include <signal.h>
  41 #include <unistd.h>
  42 #include <errno.h>
  43 #include <sys/types.h>
  44
  45 #ifdef HAVE_SYS_WAIT_H
  46 #include <sys/wait.h>
  47 #endif
  48
  49 #include "test.h"
  50
  51 static char pidpath[] = "/tmp/nbdkitpidXXXXXX";
  52
  53 static void run_test (void);
  54
  55 int
  56 main (int argc, char *argv[])
  57 {
  58   if (system ("nbdkit --exit-with-parent --version") != 0) {
  59     printf ("%s: --exit-with-parent is not implemented on this platform, "
  60             "skipping\n",
  61             argv[0]);
  62     exit (77);
  63   }
  64
  65   run_test ();
  66   exit (EXIT_SUCCESS);
  67 }
  68
  69 static void
  70 run_test (void)
  71 {
  72   pid_t ppid, nbdpid;
  73   int i, fd, status;
  74   FILE *fp;
  75   ssize_t r;
  76   size_t n;
  77   char *pidstr = NULL;
  78
  79   fd = mkstemp (pidpath);
  80   if (fd == -1) {
  81     perror ("mkstemp");
  82     exit (EXIT_FAILURE);
  83   }
  84   close (fd);
  85   unlink (pidpath);
  86
  87   /* We're going to create:
  88    *
  89    *    monitoring process (this)
  90    *       |
  91    *       `--- parent of nbdkit: waits for nbdkit to start then exits (ppid)
  92    *                |
  93    *                `--- exec nbdkit --exit-with-parent (pidpath)
  94    *
  95    * We can read the nbdkit PID in the monitoring process using
  96    * the pidpath file.
  97    */
  98   ppid = fork ();
  99   if (ppid == 0) {              /* parent of nbdkit */
 100     nbdpid = fork ();
 101     if (nbdpid == 0) {             /* exec nbdkit process */
 102       const char *argv[] = {
 103         "nbdkit", "-U", "-", "-P", pidpath, "-fv", "--exit-with-parent",
 104         "example1",
 105         NULL
 106       };
 107
 108       execvp ("nbdkit", (char **) argv);
 109       perror ("exec: nbdkit");
 110       _exit (EXIT_FAILURE);
 111     }
 112
 113     printf ("parent of nbdkit: "
 114             "monitoring process (test) = %d, "
 115             "parent of nbdkit = %d, "
 116             "nbdkit = %d\n",
 117             (int) getppid (), (int) getpid (), nbdpid);
 118     fflush (stdout);
 119
 120     /* Wait for the pidfile to turn up, which indicates that nbdkit has
 121      * started up successfully and is ready to serve requests.  However
 122      * if 'nbdpid' exits in this time it indicates a failure to start up.
 123      * Also there is a timeout in case nbdkit hangs.
 124      */
 125     for (i = 0; i < NBDKIT_START_TIMEOUT; ++i) {
 126       if (waitpid (nbdpid, NULL, WNOHANG) == nbdpid)
 127         goto early_exit;
 128
 129       if (kill (nbdpid, 0) == -1) {
 130         if (errno == ESRCH) {
 131         early_exit:
 132           fprintf (stderr,
 133                    "%s FAILED: nbdkit exited before starting to serve files\n",
 134                    program_name);
 135           nbdpid = 0;
 136           exit (EXIT_FAILURE);
 137         }
 138         perror ("kill");
 139       }
 140
 141       if (access (pidpath, F_OK) == 0)
 142         break;
 143
 144       sleep (1);
 145     }
 146
 147     printf ("parent of nbdkit: exiting\n");
 148     fflush (stdout);
 149
 150     /* nbdkit is now running, check that --exit-with-parent works
 151      * by exiting abruptly here.
 152      */
 153     _exit (EXIT_SUCCESS);
 154   }
 155
 156   /* Monitoring process. */
 157   printf ("monitor: waiting for parent of nbdkit to finish and exit\n");
 158   fflush (stdout);
 159
 160   if (waitpid (ppid, &status, 0) == -1) {
 161     perror ("waitpid (ppid)");
 162     exit (EXIT_FAILURE);
 163   }
 164   if (WIFEXITED (status) && WEXITSTATUS (status) != 0) {
 165     fprintf (stderr, "child exited unexpectedly with non-zero exit code %d\n",
 166              WEXITSTATUS (status));
 167     exit (WEXITSTATUS (status));
 168   }
 169   if (WIFSIGNALED (status)) {
 170     fprintf (stderr, "child terminated by signal %d\n", WTERMSIG (status));
 171     exit (EXIT_FAILURE);
 172   }
 173   if (WIFSTOPPED (status)) {
 174     fprintf (stderr, "child stopped by signal %d\n", WSTOPSIG (status));
 175     exit (EXIT_FAILURE);
 176   }
 177
 178   /* Get the PID of nbdkit from the pidpath file. */
 179   fp = fopen (pidpath, "r");
 180   if (fp == NULL) {
 181     perror (pidpath);
 182     exit (EXIT_FAILURE);
 183   }
 184   r = getline (&pidstr, &n, fp);
 185   if (r == -1) {
 186     perror ("read");
 187     exit (EXIT_FAILURE);
 188   }
 189   if (sscanf (pidstr, "%d", &nbdpid) != 1) {
 190     fprintf (stderr, "could not read nbdkit PID from -P pidfile (%s)\n",
 191              pidpath);
 192     exit (EXIT_FAILURE);
 193   }
 194   fclose (fp);
 195   free (pidstr);
 196   unlink (pidpath);
 197
 198   printf ("monitor: found PID of nbdkit = %d\n", nbdpid);
 199   fflush (stdout);
 200
 201   /* We expect PID to go away, but it might take a few seconds. */
 202   for (i = 0; i < NBDKIT_START_TIMEOUT; ++i) {
 203     if (kill (nbdpid, 0) == -1) {
 204       if (errno == ESRCH) goto done; /* good - gone away */
 205       perror ("kill");
 206       exit (EXIT_FAILURE);
 207     }
 208
 209     sleep (1);
 210   }
 211
 212   fprintf (stderr, "--exit-with-parent does not appear to work\n");
 213   exit (EXIT_FAILURE);
 214
 215  done:
 216   printf ("monitor: success: nbdkit exited with parent\n");
 217   fflush (stdout);
 218 }