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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 21:12:04 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 21:12:04 +0000
commiteac54b7c4aec25060d7bd856f7cdc290943d6aae (patch)
tree9a6d81c9f88df4698e746d63d14ddafeddd918b8 /src/common/tuklib_open_stdxxx.c
parentInitial commit. (diff)
downloadxz-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.c57
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;
+}