1  /* Child program invoked by test-spawn-pipe-main.
       2     Copyright (C) 2009-2023 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  #include "macros.h"
      41  
      42  static FILE *myerr;
      43  
      44  /* In this file, we use only system functions, no overrides from gnulib.  */
      45  #undef atoi
      46  #undef close
      47  #undef fcntl
      48  #undef fdopen
      49  #undef fflush
      50  #undef fprintf
      51  #undef open
      52  #undef read
      53  #undef strcasestr
      54  #undef strstr
      55  #undef write
      56  #if defined _WIN32 && !defined __CYGWIN__
      57  # define fdopen _fdopen
      58  #endif
      59  
      60  #include "qemu.h"
      61  
      62  #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
      63  static void __cdecl
      64  gl_msvc_invalid_parameter_handler (const wchar_t *expression,
      65                                     const wchar_t *function,
      66                                     const wchar_t *file,
      67                                     unsigned int line,
      68                                     uintptr_t dummy)
      69  {
      70  }
      71  #endif
      72  
      73  /* Return non-zero if FD is open.  */
      74  static int
      75  is_open (int fd)
      76  {
      77  #if defined _WIN32 && ! defined __CYGWIN__
      78    /* On native Windows, the initial state of unassigned standard file
      79       descriptors is that they are open but point to an
      80       INVALID_HANDLE_VALUE, and there is no fcntl.  */
      81    return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
      82  #else
      83  # ifndef F_GETFL
      84  #  error Please port fcntl to your platform
      85  # endif
      86    return 0 <= fcntl (fd, F_GETFL);
      87  #endif
      88  }
      89  
      90  int
      91  main (int argc, char *argv[])
      92  {
      93    /* fd 2 might be closed, but fd BACKUP_STDERR_FILENO is the original
      94       stderr.  */
      95    myerr = fdopen (BACKUP_STDERR_FILENO, "w");
      96    if (!myerr)
      97      return 2;
      98  
      99    ASSERT (argc == 2);
     100  
     101  #if HAVE_MSVC_INVALID_PARAMETER_HANDLER
     102    /* Avoid exceptions from within _get_osfhandle.  */
     103    _set_invalid_parameter_handler (gl_msvc_invalid_parameter_handler);
     104  #endif
     105  
     106    /* QEMU 6.1 in user-mode passes an open fd, usually = 3, that references
     107       /dev/urandom.  We need to ignore this fd.  */
     108    bool is_qemu = is_running_under_qemu_user ();
     109  
     110    /* Read one byte from fd 0, and write its value plus one to fd 1.
     111       fd 2 should be closed iff the argument is 1.  Check that no other file
     112       descriptors leaked.  */
     113  
     114    char buffer[2] = { 's', 't' };
     115  
     116    ASSERT (read (STDIN_FILENO, buffer, 2) == 1);
     117  
     118    buffer[0]++;
     119    ASSERT (write (STDOUT_FILENO, buffer, 1) == 1);
     120  
     121    switch (atoi (argv[1]))
     122      {
     123      case 0:
     124        /* Expect fd 2 is open.  */
     125        ASSERT (is_open (STDERR_FILENO));
     126        break;
     127      case 1:
     128        /* Expect fd 2 is closed.
     129           But on HP-UX 11, fd 2 gets automatically re-opened to /dev/null if it
     130           was closed.  Similarly on Android and on native Windows.  Future POSIX
     131           will allow this, see <http://austingroupbugs.net/view.php?id=173>.  */
     132  #if !(defined __hpux || defined __ANDROID__ || (defined _WIN32 && ! defined __CYGWIN__))
     133        if (!is_qemu)
     134          ASSERT (! is_open (STDERR_FILENO));
     135  #endif
     136        break;
     137      default:
     138        ASSERT (0);
     139      }
     140  
     141    int fd;
     142    for (fd = 3; fd < 7; fd++)
     143      if (!(is_qemu && fd == 3))
     144        {
     145          errno = 0;
     146          ASSERT (close (fd) == -1);
     147          ASSERT (errno == EBADF);
     148        }
     149  
     150    return 0;
     151  }