1 ///////////////////////////////////////////////////////////////////////////////
3 /// \file tuklib_open_stdxxx.c
4 /// \brief Make sure that file descriptors 0, 1, and 2 are open
6 // Author: Lasse Collin
8 // This file has been put into the public domain.
9 // You can do whatever you want with this file.
11 ///////////////////////////////////////////////////////////////////////////////
13 #include "tuklib_open_stdxxx.h"
15 #ifndef TUKLIB_DOSLIKE
24 tuklib_open_stdxxx(int err_status)
26 #ifndef TUKLIB_DOSLIKE
27 for (int i = 0; i <= 2; ++i) {
28 // We use fcntl() to check if the file descriptor is open.
29 if (fcntl(i, F_GETFD) == -1 && errno == EBADF) {
30 // With stdin, we could use /dev/full so that
31 // writing to stdin would fail. However, /dev/full
32 // is Linux specific, and if the program tries to
33 // write to stdin, there's already a problem anyway.
34 const int fd = open("/dev/null", O_NOCTTY
35 | (i == 0 ? O_WRONLY : O_RDONLY));
38 // Something went wrong. Exit with the
39 // exit status we were given. Don't try
40 // to print an error message, since stderr
41 // may very well be non-existent. This
42 // error should be extremely rare.