tests/test-spawn-pipe-child.c

   1 /* Child program invoked by test-spawn-pipe-main.
   2    Copyright (C) 2009-2021 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 <stdint.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25
  26 #if defined _WIN32 && ! defined __CYGWIN__
  27 /* Get declarations of the native Windows API functions.  */
  28 # define WIN32_LEAN_AND_MEAN
  29 # include <windows.h>
  30 #endif
  31
  32 /* Depending on arguments, this test intentionally closes stderr or
  33    starts life with stderr closed.  So, we arrange to have fd 10
  34    (outside the range of interesting fd's during the test) set up to
  35    duplicate the original stderr.  */
  36
  37 #define BACKUP_STDERR_FILENO 10
  38 #define ASSERT_STREAM myerr
  39 #include "macros.h"
  40
  41 static FILE *myerr;
  42
  43 /* In this file, we use only system functions, no overrides from gnulib.  */
  44 #undef atoi
  45 #undef close
  46 #undef fcntl
  47 #undef fdopen
  48 #undef fflush
  49 #undef fprintf
  50 #undef read
  51 #undef write
  52 #if defined _WIN32 && !defined __CYGWIN__
  53 # define fdopen _fdopen
  54 #endif
  55
  56 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
  57 static void __cdecl
  58 gl_msvc_invalid_parameter_handler (const wchar_t *expression,
  59                                    const wchar_t *function,
  60                                    const wchar_t *file,
  61                                    unsigned int line,
  62                                    uintptr_t dummy)
  63 {
  64 }
  65 #endif
  66
  67 /* Return non-zero if FD is open.  */
  68 static int
  69 is_open (int fd)
  70 {
  71 #if defined _WIN32 && ! defined __CYGWIN__
  72   /* On native Windows, the initial state of unassigned standard file
  73      descriptors is that they are open but point to an
  74      INVALID_HANDLE_VALUE, and there is no fcntl.  */
  75   return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
  76 #else
  77 # ifndef F_GETFL
  78 #  error Please port fcntl to your platform
  79 # endif
  80   return 0 <= fcntl (fd, F_GETFL);
  81 #endif
  82 }
  83
  84 int
  85 main (int argc, char *argv[])
  86 {
  87   /* fd 2 might be closed, but fd BACKUP_STDERR_FILENO is the original
  88      stderr.  */
  89   myerr = fdopen (BACKUP_STDERR_FILENO, "w");
  90   if (!myerr)
  91     return 2;
  92
  93   ASSERT (argc == 2);
  94
  95 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
  96   /* Avoid exceptions from within _get_osfhandle.  */
  97   _set_invalid_parameter_handler (gl_msvc_invalid_parameter_handler);
  98 #endif
  99
 100   /* Read one byte from fd 0, and write its value plus one to fd 1.
 101      fd 2 should be closed iff the argument is 1.  Check that no other file
 102      descriptors leaked.  */
 103
 104   char buffer[2] = { 's', 't' };
 105
 106   ASSERT (read (STDIN_FILENO, buffer, 2) == 1);
 107
 108   buffer[0]++;
 109   ASSERT (write (STDOUT_FILENO, buffer, 1) == 1);
 110
 111   switch (atoi (argv[1]))
 112     {
 113     case 0:
 114       /* Expect fd 2 is open.  */
 115       ASSERT (is_open (STDERR_FILENO));
 116       break;
 117     case 1:
 118       /* Expect fd 2 is closed.
 119          But on HP-UX 11, fd 2 gets automatically re-opened to /dev/null if it
 120          was closed.  Similarly on native Windows.  Future POSIX will allow
 121          this, see <http://austingroupbugs.net/view.php?id=173>.  */
 122 #if !(defined __hpux || (defined _WIN32 && ! defined __CYGWIN__))
 123       ASSERT (! is_open (STDERR_FILENO));
 124 #endif
 125       break;
 126     default:
 127       ASSERT (0);
 128     }
 129
 130   int fd;
 131   for (fd = 3; fd < 7; fd++)
 132     {
 133       errno = 0;
 134       ASSERT (close (fd) == -1);
 135       ASSERT (errno == EBADF);
 136     }
 137
 138   return 0;
 139 }