tests/test-spawn-pipe-child.c

   1 /* Child program invoked by test-spawn-pipe-main.
   2    Copyright (C) 2009-2025 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 <string.h>
  25 #include <unistd.h>
  26
  27 #if defined _WIN32 && ! defined __CYGWIN__
  28 /* Get declarations of the native Windows API functions.  */
  29 # define WIN32_LEAN_AND_MEAN
  30 # include <windows.h>
  31 #endif
  32
  33 /* Depending on arguments, this test intentionally closes stderr or
  34    starts life with stderr closed.  So, we arrange to have fd 10
  35    (outside the range of interesting fd's during the test) set up to
  36    duplicate the original stderr.  */
  37
  38 #define BACKUP_STDERR_FILENO 10
  39 #define ASSERT_STREAM myerr
  40 #undef CONTINUE_AFTER_ASSERT
  41 #include "macros.h"
  42
  43 static FILE *myerr;
  44
  45 /* In this file, we use only system functions, no overrides from gnulib.  */
  46 #undef abort
  47 #undef atoi
  48 #undef close
  49 #undef fcntl
  50 #undef fdopen
  51 #undef fflush
  52 #undef fprintf
  53 #undef open
  54 #undef read
  55 #undef strcasestr
  56 #undef strstr
  57 #undef write
  58 #if defined _WIN32 && !defined __CYGWIN__
  59 # define fdopen _fdopen
  60 #endif
  61
  62 #include "qemu.h"
  63
  64 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
  65 static void __cdecl
  66 gl_msvc_invalid_parameter_handler (const wchar_t *expression,
  67                                    const wchar_t *function,
  68                                    const wchar_t *file,
  69                                    unsigned int line,
  70                                    uintptr_t dummy)
  71 {
  72 }
  73 #endif
  74
  75 /* Return non-zero if FD is open.  */
  76 static int
  77 is_open (int fd)
  78 {
  79 #if defined _WIN32 && ! defined __CYGWIN__
  80   /* On native Windows, the initial state of unassigned standard file
  81      descriptors is that they are open but point to an
  82      INVALID_HANDLE_VALUE, and there is no fcntl.  */
  83   return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
  84 #else
  85 # ifndef F_GETFL
  86 #  error Please port fcntl to your platform
  87 # endif
  88   return 0 <= fcntl (fd, F_GETFL);
  89 #endif
  90 }
  91
  92 int
  93 main (int argc, char *argv[])
  94 {
  95   /* fd 2 might be closed, but fd BACKUP_STDERR_FILENO is the original
  96      stderr.  */
  97   myerr = fdopen (BACKUP_STDERR_FILENO, "w");
  98   if (!myerr)
  99     return 2;
 100
 101   ASSERT (argc == 2);
 102
 103 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
 104   /* Avoid exceptions from within _get_osfhandle.  */
 105   _set_invalid_parameter_handler (gl_msvc_invalid_parameter_handler);
 106 #endif
 107
 108   /* QEMU 6.1 in user-mode passes an open fd, usually = 3, that references
 109      /dev/urandom.  We need to ignore this fd.  */
 110   bool is_qemu = is_running_under_qemu_user ();
 111
 112   /* Read one byte from fd 0, and write its value plus one to fd 1.
 113      fd 2 should be closed iff the argument is 1.  Check that no other file
 114      descriptors leaked.  */
 115
 116   char buffer[2] = { 's', 't' };
 117
 118   ASSERT (read (STDIN_FILENO, buffer, 2) == 1);
 119
 120   buffer[0]++;
 121   ASSERT (write (STDOUT_FILENO, buffer, 1) == 1);
 122
 123   switch (atoi (argv[1]))
 124     {
 125     case 0:
 126       /* Expect fd 2 is open.  */
 127       ASSERT (is_open (STDERR_FILENO));
 128       break;
 129     case 1:
 130       /* Expect fd 2 is closed.
 131          But on HP-UX 11, fd 2 gets automatically re-opened to /dev/null if it
 132          was closed.  Similarly on Android and on native Windows.  Future POSIX
 133          will allow this, see <https://austingroupbugs.net/view.php?id=173>.  */
 134 #if !(defined __hpux || defined __ANDROID__ || (defined _WIN32 && ! defined __CYGWIN__))
 135       if (!is_qemu)
 136         ASSERT (! is_open (STDERR_FILENO));
 137 #endif
 138       break;
 139     default:
 140       ASSERT (0);
 141     }
 142
 143   int fd;
 144   for (fd = 3; fd < 7; fd++)
 145     if (!(is_qemu && fd == 3))
 146       {
 147         errno = 0;
 148         ASSERT (close (fd) == -1);
 149         ASSERT (errno == EBADF);
 150       }
 151
 152   return test_exit_status;
 153 }