Add fifo_open, a basic regression test for opening fifos, which tests

the blocking and non-blocking forms of open based on the POSIX spec for
now O_NONBLOCK should be handled.

tools/regression/fifo/fifo_open/Makefile

@@ -0,0 +1,7 @@
+# $FreeBSD$
+
+PROG=	fifo_open
+NO_MAN=
+WARNS=	3
+
+.include <bsd.prog.mk>

tools/regression/fifo/fifo_open/fifo_open.c

@@ -0,0 +1,474 @@
+/*-
+ * Copyright (c) 2005 Robert N. M. Watson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/*
+ * Regression test to exercise various POSIX-defined parts of fifo behavior
+ * described for open(2):
+ *
+ * O_NONBLOCK
+ * When opening a FIFO with O_RDONLY or O_WRONLY set:
+ *
+ * - If O_NONBLOCK is set, an open() for reading-only shall return without
+ *   delay. An open() for writing-only shall return an error if no process
+ *   currently has the file open for reading.
+ *
+ * - If O_NONBLOCK is clear, an open() for reading-only shall block the
+ *   calling thread until a thread opens the file for writing. An open()
+ *   for writing-only shall block the calling thread until a thread opens
+ *   the file for reading.
+ *
+ * When opening a block special or character special file that supports
+ * non-blocking opens:
+ *
+ * - If O_NONBLOCK is set, the open() function shall return without blocking
+ *   for the device to be ready or available. Subsequent behavior of the
+ *   device is device-specific.
+ *
+ * - If O_NONBLOCK is clear, the open() function shall block the calling
+ *   thread until the device is ready or available before returning.
+ *
+ * Special errors:
+ *
+ * [ENXIO]
+ * O_NONBLOCK is set, the named file is a FIFO, O_WRONLY is set, and no
+ * process has the file open for reading.
+ */
+
+/*
+ * In order to test blocking/non-blocking behavior, test processes must
+ * potentially block themselves until released.  As bugs in blocking result
+ * in processes that won't un-block, we must sacrifice a process to the task,
+ * watching and potentially killing it after a time-out.  The main test
+ * process is never used to open or act directly on a fifo (other than to
+ * create or unlink it) in order to avoid the main test process being
+ * blocked.
+ */
+
+/*
+ * All activity occurs within a temporary directory created early in the
+ * test.
+ */
+char	temp_dir[PATH_MAX];
+
+static void __unused
+atexit_temp_dir(void)
+{
+
+	rmdir(temp_dir);
+}
+
+/*
+ * Run a function in a particular test process.
+ */
+static int
+run_in_process(int (*func)(void), pid_t *pidp, const char *errstr)
+{
+	pid_t pid;
+
+	pid = fork();
+	if (pid < 0) {
+		warn("%s: run_in_process: fork", errstr);
+		return (-1);
+	}
+
+	if (pid == 0)
+		exit(func());
+
+	if (pidp != NULL)
+		*pidp = pid;
+
+	return (0);
+}
+
+/*
+ * Wait for a process on a timeout, and if the timeout expires, kill the
+ * process.  Test each second rather than waiting the full timeout at once to
+ * minimize the amount of time spent hanging around unnecessarily.
+ */
+static int
+wait_and_timeout(pid_t pid, int timeout, int *status, const char *errstr)
+{
+	pid_t wpid;
+	int i;
+
+	/*
+	 * Count up to the timeout, but do a non-hanging waitpid() after each
+	 * second so we can avoid waiting a lot of extra time.
+	 */
+	for (i = 0; i < timeout; i++) {
+		wpid = waitpid(pid, status, WNOHANG);
+		if (wpid < 0) {
+			warn("%s: wait_and_timeout: waitpid %d", errstr, pid);
+			return (-1);
+		}
+
+		if (wpid == pid)
+			return (0);
+
+		sleep(1);
+	}
+
+	wpid = waitpid(pid, status, WNOHANG);
+	if (wpid < 0) {
+		warn("%s: wait_and_timeout: waitpid %d", errstr, pid);
+		return (-1);
+	}
+
+	if (wpid == pid)
+		return (0);
+
+	if (kill(pid, SIGTERM) < 0) {
+		warn("%s: wait_and_timeout: kill %d", errstr, pid);
+		return (-1);
+	}
+
+	wpid = waitpid(pid, status, 0);
+	if (wpid < 0) {
+		warn("%s: wait_and_timeout: waitpid %d", errstr, pid);
+		return (-1);
+	}
+
+	if (wpid != pid) {
+		warn("%s: waitpid: returned %d not %d", errstr, wpid, pid);
+		return (-1);
+	}
+
+	warnx("%s: process blocked", errstr);
+	return (-1);
+}
+
+static int
+non_blocking_open_reader(void)
+{
+	int fd;
+
+	fd = open("testfifo", O_RDONLY | O_NONBLOCK);
+	if (fd < 0)
+		return (errno);
+	close(fd);
+
+	return (0);
+}
+
+static int
+non_blocking_open_writer(void)
+{
+	int fd;
+
+	fd = open("testfifo", O_WRONLY | O_NONBLOCK);
+	if (fd < 0)
+		return (errno);
+	close(fd);
+
+	return (0);
+}
+
+static int
+blocking_open_reader(void)
+{
+	int fd;
+
+	fd = open("testfifo", O_RDONLY);
+	if (fd < 0)
+		return (errno);
+	close(fd);
+
+	return (0);
+}
+
+static int
+blocking_open_writer(void)
+{
+	int fd;
+
+	fd = open("testfifo", O_WRONLY);
+	if (fd < 0)
+		return (errno);
+	close(fd);
+
+	return (0);
+}
+
+static void
+test_blocking_reader(void)
+{
+	pid_t reader_pid, writer_pid, wpid;
+	int error, status;
+
+	if (mkfifo("testfifo", 0600) < 0)
+		err(-1, "test_blocking_reader: mkfifo: testfifo");
+
+	/*
+	 * Block a process in opening the fifo.
+	 */
+	if (run_in_process(blocking_open_reader, &reader_pid,
+	    "test_blocking_reader: blocking_open_reader") < 0) {
+		(void)unlink("testfifo");
+		exit(-1);
+	}
+
+	/*
+	 * Test that it blocked.
+	 */
+	sleep(5);
+	wpid = waitpid(reader_pid, &status, WNOHANG);
+	if (wpid < 0) {
+		error = errno;
+		(void)unlink("testfifo");
+		errno = error;
+		err(-1, "test_blocking_reader: waitpid %d", reader_pid);
+	}
+
+	if (wpid != 0 && wpid != reader_pid) {
+		(void)unlink("testfifo");
+		errx(-1, "test_blocking_reader: waitpid %d returned %d",
+		    reader_pid, wpid);
+	}
+
+	if (wpid == reader_pid) {
+		(void)unlink("testfifo");
+		errx(-1, "test_blocking_reader: blocking child didn't "
+		    "block");
+	}
+
+	/*
+	 * Unblock the blocking reader.
+	 */
+	if (run_in_process(blocking_open_writer, &writer_pid,
+	    "test_blocking_reader: blocking_open_writer") < 0) {
+		(void)unlink("testfifo");
+		(void)kill(reader_pid, SIGTERM);
+		(void)waitpid(reader_pid, &status, 0);
+		exit(-1);
+	}
+
+	/*
+	 * Make sure both processes exited quickly (<1 second) to make sure
+	 * they didn't block, and GC.
+	 */
+	if (wait_and_timeout(reader_pid, 1, &status,
+	    "test_blocking_reader: blocking_open_reader") < 0) {
+		(void)unlink("testinfo");
+		(void)kill(reader_pid, SIGTERM);
+		(void)kill(writer_pid, SIGTERM);
+		exit(-1);
+	}
+	
+	if (wait_and_timeout(writer_pid, 1, &status,
+	    "test_blocking_reader: blocking_open_writer") < 0) {
+		(void)unlink("testinfo");
+		(void)kill(writer_pid, SIGTERM);
+		exit(-1);
+	}
+	
+	if (unlink("testfifo") < 0)
+		err(-1, "test_blocking_reader: unlink: testfifo");
+}
+static void
+test_blocking_writer(void)
+{
+	pid_t reader_pid, writer_pid, wpid;
+	int error, status;
+
+	if (mkfifo("testfifo", 0600) < 0)
+		err(-1, "test_blocking_writer: mkfifo: testfifo");
+
+	/*
+	 * Block a process in opening the fifo.
+	 */
+	if (run_in_process(blocking_open_writer, &writer_pid,
+	    "test_blocking_writer: blocking_open_writer") < 0) {
+		(void)unlink("testfifo");
+		exit(-1);
+	}
+
+	/*
+	 * Test that it blocked.
+	 */
+	sleep(5);
+	wpid = waitpid(writer_pid, &status, WNOHANG);
+	if (wpid < 0) {
+		error = errno;
+		(void)unlink("testfifo");
+		errno = error;
+		err(-1, "test_blocking_writer: waitpid %d", writer_pid);
+	}
+
+	if (wpid != 0 && wpid != writer_pid) {
+		(void)unlink("testfifo");
+		errx(-1, "test_blocking_writer: waitpid %d returned %d",
+		    writer_pid, wpid);
+	}
+
+	if (wpid == writer_pid) {
+		(void)unlink("testfifo");
+		errx(-1, "test_blocking_writer: blocking child didn't "
+		    "block");
+	}
+
+	/*
+	 * Unblock the blocking writer.
+	 */
+	if (run_in_process(blocking_open_reader, &reader_pid,
+	    "test_blocking_writer: blocking_open_reader") < 0) {
+		(void)unlink("testfifo");
+		(void)kill(writer_pid, SIGTERM);
+		(void)waitpid(writer_pid, &status, 0);
+		exit(-1);
+	}
+
+	/*
+	 * Make sure both processes exited quickly (<1 second) to make sure
+	 * they didn't block, and GC.
+	 */
+	if (wait_and_timeout(writer_pid, 1, &status,
+	    "test_blocking_writer: blocking_open_writer") < 0) {
+		(void)unlink("testinfo");
+		(void)kill(writer_pid, SIGTERM);
+		(void)kill(reader_pid, SIGTERM);
+		(void)waitpid(writer_pid, &status, 0);
+		(void)waitpid(reader_pid, &status, 0);
+		exit(-1);
+	}
+	
+	if (wait_and_timeout(reader_pid, 1, &status,
+	    "test_blocking_writer: blocking_open_reader") < 0) {
+		(void)unlink("testinfo");
+		(void)kill(reader_pid, SIGTERM);
+		(void)waitpid(reader_pid, &status, 0);
+		exit(-1);
+	}
+	
+	if (unlink("testfifo") < 0)
+		err(-1, "test_blocking_writer: unlink: testfifo");
+}
+
+static void
+test_non_blocking_reader(void)
+{
+	int status;
+	pid_t pid;
+
+	if (mkfifo("testfifo", 0600) < 0)
+		err(-1, "test_non_blocking_reader: mkfifo: testfifo");
+
+	if (run_in_process(non_blocking_open_reader, &pid,
+	    "test_non_blocking_reader: non_blocking_open_reader") < 0) {
+		(void)unlink("testfifo");
+		exit(-1);
+	}
+
+	status = -1;
+	if (wait_and_timeout(pid, 5, &status,
+	    "test_non_blocking_reader: non_blocking_open_reader") < 0) {
+		(void)unlink("testfifo");
+		exit(-1);
+	}
+
+	if (WEXITSTATUS(status) != 0) {
+		(void)unlink("testfifo");
+		errno = WEXITSTATUS(status);
+		err(-1, "test_non_blocking_reader: "
+		    "non_blocking_open_reader: open: testfifo");
+	}
+
+	if (unlink("testfifo") < 0)
+		err(-1, "test_non_blocking_reader: unlink: testfifo");
+}
+
+static void
+test_non_blocking_writer(void)
+{
+	int status;
+	pid_t pid;
+
+	if (mkfifo("testfifo", 0600) < 0)
+		err(-1, "test_non_blocking_writer: mkfifo: testfifo");
+
+	if (run_in_process(non_blocking_open_writer, &pid,
+	    "test_non_blocking_writer: non_blocking_open_writer") < 0) {
+		(void)unlink("testfifo");
+		exit(-1);
+	}
+
+	status = -1;
+	if (wait_and_timeout(pid, 5, &status,
+	    "test_non_blocking_writer: non_blocking_open_writer") < 0) {
+		(void)unlink("testfifo");
+		exit(-1);
+	}
+
+	if (WEXITSTATUS(status) != ENXIO) {
+		(void)unlink("testfifo");
+
+		errno = WEXITSTATUS(status);
+		if (errno == 0)
+			errx(-1, "test_non_blocking_writer: "
+			    "non_blocking_open_writer: open succeeded");
+		err(-1, "test_non_blocking_writer: "
+		    "non_blocking_open_writer: open: testfifo");
+	}
+
+	if (unlink("testfifo") < 0)
+		err(-1, "test_non_blocking_writer: unlink: testfifo");
+}
+
+int
+main(int argc, char *argv[])
+{
+
+	if (geteuid() != 0)
+		errx(-1, "must be run as root");
+
+	strcpy(temp_dir, "/tmp/fifo_create.XXXXXXXXXXX");
+	if (mkdtemp(temp_dir) == NULL)
+		err(-1, "mkdtemp");
+	atexit(atexit_temp_dir);
+
+	test_non_blocking_reader();
+	test_non_blocking_writer();
+
+	test_blocking_reader();
+	test_blocking_writer();
+
+	return (0);
+}