Test cases for pidfile(3) - including two designed to catch issues arising

from the incorrect use of fcntl(2) instead of flock(2).

tools/regression/lib/libutil/test-pidfile.c

@@ -0,0 +1,280 @@
+/*-
+ * Copyright (c) 2007-2009 Dag-Erling Coïdan Smørgrav
+ * 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
+ *    in this position and unchanged.
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/wait.h>
+
+#include <fcntl.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <libutil.h>
+
+/*
+ * We need a signal handler so kill(2) will interrupt our child's
+ * select(2) instead of killing it.
+ */
+static void
+signal_handler(int sig)
+{
+	(void)sig;
+}
+
+/*
+ * Test that pidfile_open() can create a pidfile and that pidfile_write()
+ * can write to it.
+ */
+static const char *
+test_pidfile_uncontested(void)
+{
+	const char *fn = "test_pidfile_uncontested";
+	struct pidfh *pf;
+	pid_t other = 0;
+
+	unlink(fn);
+	pf = pidfile_open(fn, 0600, &other);
+	if (pf == NULL && other != 0)
+		return ("pidfile exists and is locked");
+	if (pf == NULL)
+		return (strerror(errno));
+	if (pidfile_write(pf) != 0) {
+		pidfile_close(pf);
+		unlink(fn);
+		return ("failed to write PID");
+	}
+	pidfile_close(pf);
+	unlink(fn);
+	return (NULL);
+}
+
+/*
+ * Test that pidfile_open() locks against self.
+ */
+static const char *
+test_pidfile_self(void)
+{
+	const char *fn = "test_pidfile_self";
+	struct pidfh *pf1, *pf2;
+	pid_t other = 0;
+	int serrno;
+
+	unlink(fn);
+	pf1 = pidfile_open(fn, 0600, &other);
+	if (pf1 == NULL && other != 0)
+		return ("pidfile exists and is locked");
+	if (pf1 == NULL)
+		return (strerror(errno));
+	if (pidfile_write(pf1) != 0) {
+		serrno = errno;
+		pidfile_close(pf1);
+		unlink(fn);
+		return (strerror(serrno));
+	}
+	// second open should fail
+	pf2 = pidfile_open(fn, 0600, &other);
+	if (pf2 != NULL) {
+		pidfile_close(pf1);
+		pidfile_close(pf2);
+		unlink(fn);
+		return ("managed to opened pidfile twice");
+	}
+	if (other != getpid()) {
+		pidfile_close(pf1);
+		unlink(fn);
+		return ("pidfile contained wrong PID");
+	}
+	pidfile_close(pf1);
+	unlink(fn);
+	return (NULL);
+}
+
+/*
+ * Common code for test_pidfile_{contested,inherited}.
+ */
+static const char *
+common_test_pidfile_child(const char *fn, int parent_open)
+{
+	struct pidfh *pf = NULL;
+	pid_t other = 0, pid = 0;
+	int fd[2], serrno, status;
+	char ch;
+
+	unlink(fn);
+	if (pipe(fd) != 0)
+		return (strerror(errno));
+
+	if (parent_open) {
+		pf = pidfile_open(fn, 0600, &other);
+		if (pf == NULL && other != 0)
+			return ("pidfile exists and is locked");
+		if (pf == NULL)
+			return (strerror(errno));
+	}
+
+	pid = fork();
+	if (pid == -1)
+		return (strerror(errno));
+	if (pid == 0) {
+		// child
+		close(fd[0]);
+		signal(SIGINT, signal_handler);
+		if (!parent_open) {
+			pf = pidfile_open(fn, 0600, &other);
+			if (pf == NULL && other != 0)
+				return ("pidfile exists and is locked");
+			if (pf == NULL)
+				return (strerror(errno));
+		}
+		if (pidfile_write(pf) != 0) {
+			serrno = errno;
+			pidfile_close(pf);
+			unlink(fn);
+			return (strerror(serrno));
+		}
+		if (pf == NULL)
+			_exit(1);
+		if (pidfile_write(pf) != 0)
+			_exit(1);
+		if (write(fd[1], "*", 1) != 1)
+			_exit(1);
+		select(0, 0, 0, 0, 0);
+		_exit(0);
+	}
+	// parent
+	close(fd[1]);
+	if (pf)
+		pidfile_close(pf);
+
+	// wait for the child to signal us
+	if (read(fd[0], &ch, 1) != 1) {
+		serrno = errno;
+		unlink(fn);
+		kill(pid, SIGTERM);
+		errno = serrno;
+		return (strerror(errno));
+	}
+
+	// We shouldn't be able to lock the same pidfile as our child
+	pf = pidfile_open(fn, 0600, &other);
+	if (pf != NULL) {
+		pidfile_close(pf);
+		unlink(fn);
+		return ("managed to lock contested pidfile");
+	}
+
+	// Failed to lock, but not because it was contested
+	if (other == 0) {
+		unlink(fn);
+		return (strerror(errno));
+	}
+
+	// Locked by the wrong process
+	if (other != pid) {
+		unlink(fn);
+		return ("pidfile contained wrong PID");
+	}
+
+	// check our child's fate
+	if (pf)
+		pidfile_close(pf);
+	unlink(fn);
+	if (kill(pid, SIGINT) != 0)
+		return (strerror(errno));
+	if (waitpid(pid, &status, 0) == -1)
+		return (strerror(errno));
+	if (WIFSIGNALED(status))
+		return ("child caught signal");
+	if (WEXITSTATUS(status) != 0) 
+		return ("child returned non-zero status");
+
+	// success
+	return (NULL);
+}
+
+/*
+ * Test that pidfile_open() fails when attempting to open a pidfile that
+ * is already locked, and that it returns the correct PID.
+ */
+static const char *
+test_pidfile_contested(void)
+{
+	const char *fn = "test_pidfile_contested";
+	const char *result;
+
+	result = common_test_pidfile_child(fn, 0);
+	return (result);
+}
+
+/*
+ * Test that the pidfile lock is inherited.
+ */
+static const char *
+test_pidfile_inherited(void)
+{
+	const char *fn = "test_pidfile_inherited";
+	const char *result;
+
+	result = common_test_pidfile_child(fn, 1);
+	return (result);
+}
+
+static struct test {
+	const char *name;
+	const char *(*func)(void);
+} t[] = {
+	{ "pidfile_uncontested", test_pidfile_uncontested },
+	{ "pidfile_self", test_pidfile_self },
+	{ "pidfile_contested", test_pidfile_contested },
+	{ "pidfile_inherited", test_pidfile_inherited },
+};
+
+int
+main(void)
+{
+	const char *result;
+	int i, nt;
+
+	nt = sizeof(t) / sizeof(*t);
+	printf("1..%d\n", nt);
+	for (i = 0; i < nt; ++i) {
+		if ((result = t[i].func()) != NULL)
+			printf("not ok %d - %s # %s\n", i + 1,
+			    t[i].name, result);
+		else
+			printf("ok %d - %s\n", i + 1,
+			    t[i].name);
+	}
+	exit(0);
+}