posix/tst-vfork1.c

   1 /* Test for vfork functions.
   2    Copyright (C) 2004-2023 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 <stdio.h>
  21 #include <stdlib.h>
  22 #include <unistd.h>
  23 #include <sys/types.h>
  24 #include <sys/wait.h>
  25
  26 /* This test relies on non-POSIX functionality since the child
  27    processes call write and getpid.  */
  28 static int
  29 do_test (void)
  30 {
  31   int result = 0;
  32   int fd[2];
  33
  34   if (pipe (fd) == -1)
  35     {
  36       puts ("pipe failed");
  37       return 1;
  38     }
  39
  40   /* First vfork() without previous getpid().  */
  41   pid_t p1;
  42   if ((p1 = vfork ()) == 0)
  43     {
  44       pid_t p = getpid ();
  45       _exit (TEMP_FAILURE_RETRY (write (fd[1], &p, sizeof (p))) != sizeof (p));
  46     }
  47   else if (p1 == -1)
  48     {
  49       puts ("1st vfork failed");
  50       result = 1;
  51     }
  52
  53   pid_t p2 = 0;
  54   if (TEMP_FAILURE_RETRY (read (fd[0], &p2, sizeof (pid_t))) != sizeof (pid_t))
  55     {
  56       puts ("1st read failed");
  57       result = 1;
  58     }
  59   int r;
  60   if (TEMP_FAILURE_RETRY (waitpid (p1, &r, 0)) != p1)
  61     {
  62       puts ("1st waitpid failed");
  63       result = 1;
  64     }
  65   else if (r != 0)
  66     {
  67       puts ("write in 1st child failed");
  68       result = 1;
  69     }
  70
  71   /* Main process' ID.  */
  72   pid_t p0 = getpid ();
  73
  74   /* vfork() again, but after a getpid() in the main process.  */
  75   pid_t p3;
  76   if ((p3 = vfork ()) == 0)
  77     {
  78       pid_t p = getpid ();
  79       _exit (TEMP_FAILURE_RETRY (write (fd[1], &p, sizeof (p))) != sizeof (p));
  80     }
  81   else if (p1 == -1)
  82     {
  83       puts ("2nd vfork failed");
  84       result = 1;
  85     }
  86
  87   pid_t p4;
  88   if (TEMP_FAILURE_RETRY (read (fd[0], &p4, sizeof (pid_t))) != sizeof (pid_t))
  89     {
  90       puts ("2nd read failed");
  91       result = 1;
  92     }
  93   if (TEMP_FAILURE_RETRY (waitpid (p3, &r, 0)) != p3)
  94     {
  95       puts ("2nd waitpid failed");
  96       result = 1;
  97     }
  98   else if (r != 0)
  99     {
 100       puts ("write in 2nd child failed");
 101       result = 1;
 102     }
 103
 104   /* And getpid in the main process again.  */
 105   pid_t p5 = getpid ();
 106
 107   /* Analysis of the results.  */
 108   if (p0 != p5)
 109     {
 110       printf ("p0(%ld) != p5(%ld)\n", (long int) p0, (long int) p5);
 111       result = 1;
 112     }
 113
 114   if (p0 == p1)
 115     {
 116       printf ("p0(%ld) == p1(%ld)\n", (long int) p0, (long int) p1);
 117       result = 1;
 118     }
 119
 120   if (p1 != p2)
 121     {
 122       printf ("p1(%ld) != p2(%ld)\n", (long int) p1, (long int) p2);
 123       result = 1;
 124     }
 125
 126   if (p0 == p3)
 127     {
 128       printf ("p0(%ld) == p3(%ld)\n", (long int) p0, (long int) p3);
 129       result = 1;
 130     }
 131
 132   if (p3 != p4)
 133     {
 134       printf ("p3(%ld) != p4(%ld)\n", (long int) p3, (long int) p4);
 135       result = 1;
 136     }
 137
 138   close (fd[0]);
 139   close (fd[1]);
 140
 141   if (result == 0)
 142     puts ("All OK");
 143
 144   return result;
 145 }
 146
 147 #define TEST_FUNCTION do_test ()
 148 #include "../test-skeleton.c"