posix/tst-vfork1.c

   1 /* Test for vfork functions.
   2    Copyright (C) 2004-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
   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    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <errno.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <sys/types.h>
  25 #include <sys/wait.h>
  26
  27 /* This test relies on non-POSIX functionality since the child
  28    processes call write and getpid.  */
  29 static int
  30 do_test (void)
  31 {
  32   int result = 0;
  33   int fd[2];
  34
  35   if (pipe (fd) == -1)
  36     {
  37       puts ("pipe failed");
  38       return 1;
  39     }
  40
  41   /* First vfork() without previous getpid().  */
  42   pid_t p1;
  43   if ((p1 = vfork ()) == 0)
  44     {
  45       pid_t p = getpid ();
  46       _exit (TEMP_FAILURE_RETRY (write (fd[1], &p, sizeof (p))) != sizeof (p));
  47     }
  48   else if (p1 == -1)
  49     {
  50       puts ("1st vfork failed");
  51       result = 1;
  52     }
  53
  54   pid_t p2 = 0;
  55   if (TEMP_FAILURE_RETRY (read (fd[0], &p2, sizeof (pid_t))) != sizeof (pid_t))
  56     {
  57       puts ("1st read failed");
  58       result = 1;
  59     }
  60   int r;
  61   if (TEMP_FAILURE_RETRY (waitpid (p1, &r, 0)) != p1)
  62     {
  63       puts ("1st waitpid failed");
  64       result = 1;
  65     }
  66   else if (r != 0)
  67     {
  68       puts ("write in 1st child failed");
  69       result = 1;
  70     }
  71
  72   /* Main process' ID.  */
  73   pid_t p0 = getpid ();
  74
  75   /* vfork() again, but after a getpid() in the main process.  */
  76   pid_t p3;
  77   if ((p3 = vfork ()) == 0)
  78     {
  79       pid_t p = getpid ();
  80       _exit (TEMP_FAILURE_RETRY (write (fd[1], &p, sizeof (p))) != sizeof (p));
  81     }
  82   else if (p1 == -1)
  83     {
  84       puts ("2nd vfork failed");
  85       result = 1;
  86     }
  87
  88   pid_t p4;
  89   if (TEMP_FAILURE_RETRY (read (fd[0], &p4, sizeof (pid_t))) != sizeof (pid_t))
  90     {
  91       puts ("2nd read failed");
  92       result = 1;
  93     }
  94   if (TEMP_FAILURE_RETRY (waitpid (p3, &r, 0)) != p3)
  95     {
  96       puts ("2nd waitpid failed");
  97       result = 1;
  98     }
  99   else if (r != 0)
 100     {
 101       puts ("write in 2nd child failed");
 102       result = 1;
 103     }
 104
 105   /* And getpid in the main process again.  */
 106   pid_t p5 = getpid ();
 107
 108   /* Analysis of the results.  */
 109   if (p0 != p5)
 110     {
 111       printf ("p0(%ld) != p5(%ld)\n", (long int) p0, (long int) p5);
 112       result = 1;
 113     }
 114
 115   if (p0 == p1)
 116     {
 117       printf ("p0(%ld) == p1(%ld)\n", (long int) p0, (long int) p1);
 118       result = 1;
 119     }
 120
 121   if (p1 != p2)
 122     {
 123       printf ("p1(%ld) != p2(%ld)\n", (long int) p1, (long int) p2);
 124       result = 1;
 125     }
 126
 127   if (p0 == p3)
 128     {
 129       printf ("p0(%ld) == p3(%ld)\n", (long int) p0, (long int) p3);
 130       result = 1;
 131     }
 132
 133   if (p3 != p4)
 134     {
 135       printf ("p3(%ld) != p4(%ld)\n", (long int) p3, (long int) p4);
 136       result = 1;
 137     }
 138
 139   close (fd[0]);
 140   close (fd[1]);
 141
 142   if (result == 0)
 143     puts ("All OK");
 144
 145   return result;
 146 }
 147
 148 #define TEST_FUNCTION do_test ()
 149 #include "../test-skeleton.c"