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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 21:12:04 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 21:12:04 +0000 |
commit | eac54b7c4aec25060d7bd856f7cdc290943d6aae (patch) | |
tree | 9a6d81c9f88df4698e746d63d14ddafeddd918b8 /src/common/tuklib_open_stdxxx.c | |
parent | Initial commit. (diff) | |
download | xz-utils-eac54b7c4aec25060d7bd856f7cdc290943d6aae.tar.xz xz-utils-eac54b7c4aec25060d7bd856f7cdc290943d6aae.zip |
Adding upstream version 5.4.1.upstream/5.4.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/common/tuklib_open_stdxxx.c')
-rw-r--r-- | src/common/tuklib_open_stdxxx.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/src/common/tuklib_open_stdxxx.c b/src/common/tuklib_open_stdxxx.c new file mode 100644 index 0000000..26702a6 --- /dev/null +++ b/src/common/tuklib_open_stdxxx.c @@ -0,0 +1,57 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file tuklib_open_stdxxx.c +/// \brief Make sure that file descriptors 0, 1, and 2 are open +// +// Author: Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "tuklib_open_stdxxx.h" + +#ifndef TUKLIB_DOSLIKE +# include <stdlib.h> +# include <errno.h> +# include <fcntl.h> +# include <unistd.h> +#endif + + +extern void +tuklib_open_stdxxx(int err_status) +{ +#ifdef TUKLIB_DOSLIKE + // Do nothing, just silence warnings. + (void)err_status; + +#else + for (int i = 0; i <= 2; ++i) { + // We use fcntl() to check if the file descriptor is open. + if (fcntl(i, F_GETFD) == -1 && errno == EBADF) { + // With stdin, we could use /dev/full so that + // writing to stdin would fail. However, /dev/full + // is Linux specific, and if the program tries to + // write to stdin, there's already a problem anyway. + const int fd = open("/dev/null", O_NOCTTY + | (i == 0 ? O_WRONLY : O_RDONLY)); + + if (fd != i) { + if (fd != -1) + (void)close(fd); + + // Something went wrong. Exit with the + // exit status we were given. Don't try + // to print an error message, since stderr + // may very well be non-existent. This + // error should be extremely rare. + exit(err_status); + } + } + } +#endif + + return; +} |