1 files changed, 40 insertions, 0 deletions
diff --git a/gnu/usr.bin/cvs/lib/dup2.c b/gnu/usr.bin/cvs/lib/dup2.c
new file mode 100644
index 000000000000..19743830ca6e
--- /dev/null
+++ b/gnu/usr.bin/cvs/lib/dup2.c
@@ -0,0 +1,40 @@
+/*
+	dup2 -- 7th Edition UNIX system call emulation for UNIX System V
+
+	last edit:	11-Feb-1987	D A Gwyn
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include	<errno.h>
+#include	<fcntl.h>
+
+extern int	close(), fcntl();
+
+int
+dup2( oldfd, newfd )
+	int		oldfd;		/* already-open file descriptor */
+	int		newfd;		/* desired duplicate descriptor */
+{
+	register int	ret;		/* for fcntl() return value */
+	register int	save;		/* for saving entry errno */
+
+	if ( oldfd == newfd )
+		return oldfd;		/* be careful not to close() */
+
+	save = errno;			/* save entry errno */
+	(void) close( newfd );		/* in case newfd is open */
+	/* (may have just clobbered the original errno value) */
+
+	ret = fcntl( oldfd, F_DUPFD, newfd );	/* dupe it */
+
+	if ( ret >= 0 )
+		errno = save;		/* restore entry errno */
+	else				/* fcntl() returned error */
+		if ( errno == EINVAL )
+			errno = EBADF;	/* we think of everything */
+
+	return ret;			/* return file descriptor */
+}