tests/test-spawn-pipe-child.c

   1 /* Child program invoked by test-spawn-pipe-main.
   2    Copyright (C) 2009-2019 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24
  25 #if defined _WIN32 && ! defined __CYGWIN__
  26 /* Get declarations of the native Windows API functions.  */
  27 # define WIN32_LEAN_AND_MEAN
  28 # include <windows.h>
  29 #endif
  30
  31 /* Depending on arguments, this test intentionally closes stderr or
  32    starts life with stderr closed.  So, we arrange to have fd 10
  33    (outside the range of interesting fd's during the test) set up to
  34    duplicate the original stderr.  */
  35
  36 #define BACKUP_STDERR_FILENO 10
  37 #define ASSERT_STREAM myerr
  38 #include "macros.h"
  39
  40 static FILE *myerr;
  41
  42 /* In this file, we use only system functions, no overrides from gnulib.  */
  43 #undef atoi
  44 #undef close
  45 #undef fcntl
  46 #undef fdopen
  47 #undef fflush
  48 #undef fprintf
  49 #undef read
  50 #undef write
  51
  52 /* Return non-zero if FD is open.  */
  53 static int
  54 is_open (int fd)
  55 {
  56 #if defined _WIN32 && ! defined __CYGWIN__
  57   /* On native Windows, the initial state of unassigned standard file
  58      descriptors is that they are open but point to an
  59      INVALID_HANDLE_VALUE, and there is no fcntl.  */
  60   return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
  61 #else
  62 # ifndef F_GETFL
  63 #  error Please port fcntl to your platform
  64 # endif
  65   return 0 <= fcntl (fd, F_GETFL);
  66 #endif
  67 }
  68
  69 int
  70 main (int argc, char *argv[])
  71 {
  72   char buffer[2] = { 's', 't' };
  73   int fd;
  74
  75   /* fd 2 might be closed, but fd BACKUP_STDERR_FILENO is the original
  76      stderr.  */
  77   myerr = fdopen (BACKUP_STDERR_FILENO, "w");
  78   if (!myerr)
  79     return 2;
  80
  81   ASSERT (argc == 2);
  82
  83   /* Read one byte from fd 0, and write its value plus one to fd 1.
  84      fd 2 should be closed iff the argument is 1.  Check that no other file
  85      descriptors leaked.  */
  86
  87   ASSERT (read (STDIN_FILENO, buffer, 2) == 1);
  88
  89   buffer[0]++;
  90   ASSERT (write (STDOUT_FILENO, buffer, 1) == 1);
  91
  92   switch (atoi (argv[1]))
  93     {
  94     case 0:
  95       /* Expect fd 2 is open.  */
  96       ASSERT (is_open (STDERR_FILENO));
  97       break;
  98     case 1:
  99       /* Expect fd 2 is closed.
 100          But on HP-UX 11, fd 2 gets automatically re-opened to /dev/null if it
 101          was closed.  Similarly on native Windows.  Future POSIX will allow
 102          this, see <http://austingroupbugs.net/view.php?id=173>.  */
 103 #if !(defined __hpux || (defined _WIN32 && ! defined __CYGWIN__))
 104       ASSERT (! is_open (STDERR_FILENO));
 105 #endif
 106       break;
 107     default:
 108       ASSERT (0);
 109     }
 110
 111   for (fd = 3; fd < 7; fd++)
 112     {
 113       errno = 0;
 114       ASSERT (close (fd) == -1);
 115       ASSERT (errno == EBADF);
 116     }
 117
 118   return 0;
 119 }