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 <unistd.h>
  41 #include <sys/types.h>
  42 #include <sys/wait.h>
  43 #include <errno.h>
  44
  45 #include "exit-with-parent.h"
  46 #include "test.h"
  47
  48 static char pidpath[] = "/tmp/nbdkitpidXXXXXX";
  49
  50 static void run_test (void);
  51
  52 int
  53 main (int argc, char *argv[])
  54 {
  55 #ifndef HAVE_EXIT_WITH_PARENT
  56   printf ("--exit-with-parent is not implemented on this platform, skipping\n");
  57   exit (77);
  58 #else
  59   run_test ();
  60   exit (EXIT_SUCCESS);
  61 #endif
  62 }
  63
  64 static void
  65 run_test (void)
  66 {
  67   pid_t cpid, nbdpid;
  68   int i, fd, status;
  69   FILE *fp;
  70   ssize_t r;
  71   size_t n;
  72   char *pidstr;
  73
  74   fd = mkstemp (pidpath);
  75   if (fd == -1) {
  76     perror ("mkstemp");
  77     exit (EXIT_FAILURE);
  78   }
  79   close (fd);
  80   unlink (pidpath);
  81
  82   /* We're going to create:
  83    *
  84    *    monitoring process (this)
  85    *       |
  86    *       `--- child process waits for nbdkit to start then exits (cpid)
  87    *                |
  88    *                `--- exec nbdkit --exit-with-parent (pidpath)
  89    *
  90    * We can read the nbdkit PID in the monitoring process using
  91    * the pidpath file.
  92    */
  93   cpid = fork ();
  94   if (cpid == 0) {              /* child process */
  95     nbdpid = fork ();
  96     if (nbdpid == 0) {             /* exec nbdkit process */
  97       const char *argv[] = {
  98         "nbdkit", "-U", "-", "-P", pidpath, "-f", "--exit-with-parent",
  99         "example1",
 100         NULL
 101       };
 102
 103       execvp ("nbdkit", (char **) argv);
 104       perror ("exec: nbdkit");
 105       _exit (EXIT_FAILURE);
 106     }
 107
 108     /* Wait for the pidfile to turn up, which indicates that nbdkit has
 109      * started up successfully and is ready to serve requests.  However
 110      * if 'nbdpid' exits in this time it indicates a failure to start up.
 111      * Also there is a timeout in case nbdkit hangs.
 112      */
 113     for (i = 0; i < NBDKIT_START_TIMEOUT; ++i) {
 114       if (waitpid (nbdpid, NULL, WNOHANG) == nbdpid)
 115         goto early_exit;
 116
 117       if (kill (nbdpid, 0) == -1) {
 118         if (errno == ESRCH) {
 119         early_exit:
 120           fprintf (stderr,
 121                    "%s FAILED: nbdkit exited before starting to serve files\n",
 122                    program_name);
 123           nbdpid = 0;
 124           exit (EXIT_FAILURE);
 125         }
 126         perror ("kill");
 127       }
 128
 129       if (access (pidpath, F_OK) == 0)
 130         break;
 131
 132       sleep (1);
 133     }
 134
 135     /* nbdkit is now running, check that --exit-with-parent works
 136      * by exiting abruptly here.
 137      */
 138     _exit (EXIT_SUCCESS);
 139   }
 140
 141   /* Monitoring process. */
 142   if (waitpid (cpid, &status, 0) == -1) {
 143     perror ("waitpid (cpid)");
 144     exit (EXIT_FAILURE);
 145   }
 146   if (WIFEXITED (status) && WEXITSTATUS (status) != 1)
 147     exit (WEXITSTATUS (status));
 148   if (WIFSIGNALED (status)) {
 149     fprintf (stderr, "child terminated by signal %d\n", WTERMSIG (status));
 150     exit (EXIT_FAILURE);
 151   }
 152   if (WIFSTOPPED (status)) {
 153     fprintf (stderr, "child stopped by signal %d\n", WSTOPSIG (status));
 154     exit (EXIT_FAILURE);
 155   }
 156
 157   /* Get the PID of nbdkit from the pidpath file. */
 158   fp = fopen (pidpath, "r");
 159   if (fp == NULL) {
 160     perror (pidpath);
 161     exit (EXIT_FAILURE);
 162   }
 163   r = getline (&pidstr, &n, fp);
 164   if (r == -1) {
 165     perror ("read");
 166     exit (EXIT_FAILURE);
 167   }
 168   if (sscanf (pidstr, "%d", &nbdpid) != 1) {
 169     fprintf (stderr, "could not read nbdkit PID from -P pidfile (%s)\n",
 170              pidpath);
 171     exit (EXIT_FAILURE);
 172   }
 173   fclose (fp);
 174   free (pidstr);
 175   unlink (pidpath);
 176
 177   /* We expect PID to go away, but it might take a few seconds. */
 178   for (i = 0; i < NBDKIT_START_TIMEOUT; ++i) {
 179     if (kill (nbdpid, 0) == -1) {
 180       if (errno == ESRCH) goto done; /* good - gone away */
 181       perror ("kill");
 182       exit (EXIT_FAILURE);
 183     }
 184
 185     sleep (1);
 186   }
 187
 188   fprintf (stderr, "--exit-with-parent does not appear to work\n");
 189   exit (EXIT_FAILURE);
 190
 191  done:
 192   ;
 193 }