1 files changed, 64 insertions, 0 deletions
diff --git a/src/util/dup2_pass_on_exec.c b/src/util/dup2_pass_on_exec.c
new file mode 100644
index 0000000..df0e21c
--- /dev/null
+++ b/src/util/dup2_pass_on_exec.c
@@ -0,0 +1,64 @@
+/*++
+/* NAME
+/*	dup2_pass_on_exec 1
+/* SUMMARY
+/*	dup2 close-on-exec behaviour test program
+/* SYNOPSIS
+/*	dup2_pass_on_exec
+/* DESCRIPTION
+/*	dup2_pass_on_exec sets the close-on-exec flag on its
+/*	standard input and then dup2() to duplicate it.
+/*	Posix-1003.1 specifies in section 6.2.1.2 that dup2(o,n) should behave
+/*	as: close(n); n = fcntl(o, F_DUPFD, n); as long as o is a valid
+/*	file-descriptor, n!=o, and 0<=n<=[OPEN_MAX].
+/*	Section 6.5.2.2 states that the close-on-exec flag of the result of a
+/*	successful fcntl(o, F_DUPFD, n) is cleared.
+/*
+/*	At least Ultrix4.3a does not clear the close-on-exec flag of n on
+/*	dup2(o, n).
+/* DIAGNOSTICS
+/*	Problems are reported to the standard error stream.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Christian von Roques <roques@pond.sub.org>
+/*	Forststrasse 71
+/*	76131 Karlsruhe, GERMANY
+/*--*/
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#define DO(s)	if (s < 0) { perror(#s); exit(1); }
+
+int     main(int unused_argc, char **unused_argv)
+{
+    int     res;
+
+    printf("Setting the close-on-exec flag of file-descriptor 0.\n");
+    DO(fcntl(0, F_SETFD, 1));
+
+    printf("Duplicating file-descriptor 0 to 3.\n");
+    DO(dup2(0, 3));
+
+    printf("Testing if the close-on-exec flag of file-descriptor 3 is set.\n");
+    DO((res = fcntl(3, F_GETFD, 0)));
+    if (res & 1)
+	printf(
+"Yes, a newly dup2()ed file-descriptor has the close-on-exec \
+flag cloned.\n\
+THIS VIOLATES Posix1003.1 section 6.2.1.2 or 6.5.2.2!\n\
+You should #define DUP2_DUPS_CLOSE_ON_EXEC in sys_defs.h \
+for your OS.\n");
+    else
+	printf(
+"No, a newly dup2()ed file-descriptor has the close-on-exec \
+flag cleared.\n\
+This complies with Posix1003.1 section 6.2.1.2 and 6.5.2.2!\n");
+
+    return 0;
+}