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authorLasse Collin <lasse.collin@tukaani.org>2007-12-09 00:42:33 +0200
committerLasse Collin <lasse.collin@tukaani.org>2007-12-09 00:42:33 +0200
commit5d018dc03549c1ee4958364712fb0c94e1bf2741 (patch)
tree1b211911fb33fddb3f04b77f99e81df23623ffc4 /src/common/open_stdxxx.h
downloadxz-5d018dc03549c1ee4958364712fb0c94e1bf2741.tar.xz
Imported to git.
Diffstat (limited to 'src/common/open_stdxxx.h')
-rw-r--r--src/common/open_stdxxx.h50
1 files changed, 50 insertions, 0 deletions
diff --git a/src/common/open_stdxxx.h b/src/common/open_stdxxx.h
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--- /dev/null
+++ b/src/common/open_stdxxx.h
@@ -0,0 +1,50 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file open_stdxxx.h
+/// \brief Make sure that file descriptors 0, 1, and 2 are open
+//
+// This code has been put into the public domain.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef OPEN_STDXXX_H
+#define OPEN_STDXXX_H
+
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+
+static void
+open_stdxxx(int status)
+{
+ 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) {
+ // 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.
+ (void)close(fd);
+ exit(status);
+ }
+ }
+ }
+
+ return;
+}
+
+#endif