Enhance the blocking test and add a test for closing while half-open

1 files changed, 72 insertions, 7 deletions

diff --git a/regress/lib/libpthread/blocked_fifo/blocked_fifo.c b/regress/lib/libpthread/blocked_fifo/blocked_fifo.c
index c5dc63bc45d..3b50f86878e 100644
--- a/regress/lib/libpthread/blocked_fifo/blocked_fifo.c
+++ b/regress/lib/libpthread/blocked_fifo/blocked_fifo.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: blocked_fifo.c,v 1.1 2012/03/19 17:41:57 oga Exp $	*/
+/*	$OpenBSD: blocked_fifo.c,v 1.2 2012/07/08 11:35:37 guenther Exp $	*/
 /*
  * Copyright (c) 2012 Owain G. Ainsworth <oga@openbsd.org>
  *
@@ -30,9 +30,11 @@
 #include <fcntl.h>
 #include "test.h"
 
-#define FIFO	"/tmp/pthread.fifo"
+#define FIFO	"pthread.fifo"
 #define FILE	"/etc/services"	/* just any file to deadlock on */
 
+int	free_fd, expected_fd;
+
 static void *
 deadlock_detector(void *arg)
 {
@@ -55,6 +57,30 @@ fifo_deadlocker(void *arg)
 
 	/* open fifo to unblock other thread */
 	CHECKe(fd = open(FIFO, O_WRONLY));
+	CHECKe(write(fd, "test", 4));
+	CHECKe(close(fd));
+
+	return ((caddr_t)NULL + errno);
+}
+
+static void *
+fifo_closer(void *arg)
+{
+	int	fd;
+
+	/* let other fifo open start */
+	sleep(3);
+
+	/* open a random temporary file and dup2 it over the FIFO */
+	CHECKe(fd = open(FILE, O_RDONLY));
+	CHECKe(dup2(fd, expected_fd));
+	CHECKe(close(fd));
+	CHECKe(close(expected_fd));
+
+	/* open fifo to unblock other thread */
+	CHECKe(fd = open(FIFO, O_WRONLY));
+	CHECKe(write(fd, "test", 4));
+	CHECKe(close(fd));
 
 	return ((caddr_t)NULL + errno);
 }
@@ -62,21 +88,60 @@ fifo_deadlocker(void *arg)
 int
 main(int argc, char *argv[])
 {
-	pthread_t	 deadlock_thread, deadlock_finder;
+	pthread_t	 test_thread, deadlock_finder;
+	struct stat	 st;
+	char		 buf[5];
 	int		 fd;
+	ssize_t		 rlen;
 
+	unlink(FIFO);
 	CHECKe(mkfifo(FIFO, S_IRUSR | S_IWUSR));
 
-	CHECKr(pthread_create(&deadlock_thread, NULL,
-	    fifo_deadlocker, NULL));
 	CHECKr(pthread_create(&deadlock_finder, NULL,
 	    deadlock_detector, NULL));
 
-	/* Open fifo (this will sleep until we have readers */
+	/*
+	 * Verify that other threads can still do fd-table operations
+	 * while a thread is blocked opening a FIFO
+	 */
+	CHECKr(pthread_create(&test_thread, NULL, fifo_deadlocker, NULL));
+
+	/* Open fifo (this will sleep until we have readers) */
+	CHECKe(fd = open(FIFO, O_RDONLY));
+
+	CHECKe(fstat(fd, &st));
+	ASSERT(S_ISFIFO(st.st_mode));
+	CHECKe(rlen = read(fd, buf, sizeof buf));
+	ASSERT(rlen == 4);
+
+	CHECKr(pthread_join(test_thread, NULL));
+
+	CHECKe(close(fd));
+
+
+	/*
+	 * Verify that if a thread is blocked opening a FIFO and another
+	 * thread targets the half-open fd with dup2 that it doesn't blow up.
+	 */
+	CHECKr(pthread_create(&test_thread, NULL, fifo_closer, NULL));
+
+	free_fd = open("/dev/null", O_RDONLY);
+	expected_fd = dup(free_fd);
+	close(expected_fd);
+
+	/* Open fifo (this will sleep until we have readers) */
 	CHECKe(fd = open(FIFO, O_RDONLY));
 
-	CHECKr(pthread_join(deadlock_thread, NULL));
+	ASSERT(fd == expected_fd);
+	ASSERT(close(fd) == -1);
+	ASSERT(errno == EBADF);
+
+	CHECKr(pthread_join(test_thread, NULL));
+
+	CHECKe(close(free_fd));
+
 
+	/* clean up */
 	unlink(FIFO);
 
 	SUCCEED;