selftests: add mq_open_tests

Add a directory to house POSIX message queue subsystem specific tests.
Add first test which checks the operation of mq_open() under various
corner conditions.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Joe Korty <joe.korty@ccur.com>
Cc: Amerigo Wang <amwang@redhat.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/selftests/Makefile

-TARGETS = breakpoints vm
+TARGETS = breakpoints mqueue vm
 
 all:
 	for TARGET in $(TARGETS); do \

tools/testing/selftests/mqueue/Makefile

+all:
+	gcc -O2 -lrt mq_open_tests.c -o mq_open_tests
+
+run_tests:
+	./mq_open_tests /test1
+
+clean:
+	rm -f mq_open_tests

tools/testing/selftests/mqueue/mq_open_tests.c

+/*
+ * This application is Copyright 2012 Red Hat, Inc.
+ *	Doug Ledford <dledford@redhat.com>
+ *
+ * mq_open_tests is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * mq_open_tests is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * For the full text of the license, see <http://www.gnu.org/licenses/>.
+ *
+ * mq_open_tests.c
+ *   Tests the various situations that should either succeed or fail to
+ *   open a posix message queue and then reports whether or not they
+ *   did as they were supposed to.
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <limits.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <mqueue.h>
+
+static char *usage =
+"Usage:\n"
+"  %s path\n"
+"\n"
+"	path	Path name of the message queue to create\n"
+"\n"
+"	Note: this program must be run as root in order to enable all tests\n"
+"\n";
+
+char *DEF_MSGS = "/proc/sys/fs/mqueue/msg_default";
+char *DEF_MSGSIZE = "/proc/sys/fs/mqueue/msgsize_default";
+char *MAX_MSGS = "/proc/sys/fs/mqueue/msg_max";
+char *MAX_MSGSIZE = "/proc/sys/fs/mqueue/msgsize_max";
+
+int default_settings;
+struct rlimit saved_limits, cur_limits;
+int saved_def_msgs, saved_def_msgsize, saved_max_msgs, saved_max_msgsize;
+int cur_def_msgs, cur_def_msgsize, cur_max_msgs, cur_max_msgsize;
+FILE *def_msgs, *def_msgsize, *max_msgs, *max_msgsize;
+char *queue_path;
+mqd_t queue = -1;
+
+static inline void __set(FILE *stream, int value, char *err_msg);
+void shutdown(int exit_val, char *err_cause, int line_no);
+static inline int get(FILE *stream);
+static inline void set(FILE *stream, int value);
+static inline void getr(int type, struct rlimit *rlim);
+static inline void setr(int type, struct rlimit *rlim);
+void validate_current_settings();
+static inline void test_queue(struct mq_attr *attr, struct mq_attr *result);
+static inline int test_queue_fail(struct mq_attr *attr, struct mq_attr *result);
+
+static inline void __set(FILE *stream, int value, char *err_msg)
+{
+	rewind(stream);
+	if (fprintf(stream, "%d", value) < 0)
+		perror(err_msg);
+}
+
+
+void shutdown(int exit_val, char *err_cause, int line_no)
+{
+	static int in_shutdown = 0;
+
+	/* In case we get called recursively by a set() call below */
+	if (in_shutdown++)
+		return;
+
+	seteuid(0);
+
+	if (queue != -1)
+		if (mq_close(queue))
+			perror("mq_close() during shutdown");
+	if (queue_path)
+		/*
+		 * Be silent if this fails, if we cleaned up already it's
+		 * expected to fail
+		 */
+		mq_unlink(queue_path);
+	if (default_settings) {
+		if (saved_def_msgs)
+			__set(def_msgs, saved_def_msgs,
+			      "failed to restore saved_def_msgs");
+		if (saved_def_msgsize)
+			__set(def_msgsize, saved_def_msgsize,
+			      "failed to restore saved_def_msgsize");
+	}
+	if (saved_max_msgs)
+		__set(max_msgs, saved_max_msgs,
+		      "failed to restore saved_max_msgs");
+	if (saved_max_msgsize)
+		__set(max_msgsize, saved_max_msgsize,
+		      "failed to restore saved_max_msgsize");
+	if (exit_val)
+		error(exit_val, errno, "%s at %d", err_cause, line_no);
+	exit(0);
+}
+
+static inline int get(FILE *stream)
+{
+	int value;
+	rewind(stream);
+	if (fscanf(stream, "%d", &value) != 1)
+		shutdown(4, "Error reading /proc entry", __LINE__ - 1);
+	return value;
+}
+
+static inline void set(FILE *stream, int value)
+{
+	int new_value;
+
+	rewind(stream);
+	if (fprintf(stream, "%d", value) < 0)
+		return shutdown(5, "Failed writing to /proc file",
+				__LINE__ - 1);
+	new_value = get(stream);
+	if (new_value != value)
+		return shutdown(5, "We didn't get what we wrote to /proc back",
+				__LINE__ - 1);
+}
+
+static inline void getr(int type, struct rlimit *rlim)
+{
+	if (getrlimit(type, rlim))
+		shutdown(6, "getrlimit()", __LINE__ - 1);
+}
+
+static inline void setr(int type, struct rlimit *rlim)
+{
+	if (setrlimit(type, rlim))
+		shutdown(7, "setrlimit()", __LINE__ - 1);
+}
+
+void validate_current_settings()
+{
+	int rlim_needed;
+
+	if (cur_limits.rlim_cur < 4096) {
+		printf("Current rlimit value for POSIX message queue bytes is "
+		       "unreasonably low,\nincreasing.\n\n");
+		cur_limits.rlim_cur = 8192;
+		cur_limits.rlim_max = 16384;
+		setr(RLIMIT_MSGQUEUE, &cur_limits);
+	}
+
+	if (default_settings) {
+		rlim_needed = (cur_def_msgs + 1) * (cur_def_msgsize + 1 +
+						    2 * sizeof(void *));
+		if (rlim_needed > cur_limits.rlim_cur) {
+			printf("Temporarily lowering default queue parameters "
+			       "to something that will work\n"
+			       "with the current rlimit values.\n\n");
+			set(def_msgs, 10);
+			cur_def_msgs = 10;
+			set(def_msgsize, 128);
+			cur_def_msgsize = 128;
+		}
+	} else {
+		rlim_needed = (cur_max_msgs + 1) * (cur_max_msgsize + 1 +
+						    2 * sizeof(void *));
+		if (rlim_needed > cur_limits.rlim_cur) {
+			printf("Temporarily lowering maximum queue parameters "
+			       "to something that will work\n"
+			       "with the current rlimit values in case this is "
+			       "a kernel that ties the default\n"
+			       "queue parameters to the maximum queue "
+			       "parameters.\n\n");
+			set(max_msgs, 10);
+			cur_max_msgs = 10;
+			set(max_msgsize, 128);
+			cur_max_msgsize = 128;
+		}
+	}
+}
+
+/*
+ * test_queue - Test opening a queue, shutdown if we fail.  This should
+ * only be called in situations that should never fail.  We clean up
+ * after ourselves and return the queue attributes in *result.
+ */
+static inline void test_queue(struct mq_attr *attr, struct mq_attr *result)
+{
+	int flags = O_RDWR | O_EXCL | O_CREAT;
+	int perms = DEFFILEMODE;
+
+	if ((queue = mq_open(queue_path, flags, perms, attr)) == -1)
+		shutdown(1, "mq_open()", __LINE__);
+	if (mq_getattr(queue, result))
+		shutdown(1, "mq_getattr()", __LINE__);
+	if (mq_close(queue))
+		shutdown(1, "mq_close()", __LINE__);
+	queue = -1;
+	if (mq_unlink(queue_path))
+		shutdown(1, "mq_unlink()", __LINE__);
+}
+
+/*
+ * Same as test_queue above, but failure is not fatal.
+ * Returns:
+ * 0 - Failed to create a queue
+ * 1 - Created a queue, attributes in *result
+ */
+static inline int test_queue_fail(struct mq_attr *attr, struct mq_attr *result)
+{
+	int flags = O_RDWR | O_EXCL | O_CREAT;
+	int perms = DEFFILEMODE;
+
+	if ((queue = mq_open(queue_path, flags, perms, attr)) == -1)
+		return 0;
+	if (mq_getattr(queue, result))
+		shutdown(1, "mq_getattr()", __LINE__);
+	if (mq_close(queue))
+		shutdown(1, "mq_close()", __LINE__);
+	queue = -1;
+	if (mq_unlink(queue_path))
+		shutdown(1, "mq_unlink()", __LINE__);
+	return 1;
+}
+
+int main(int argc, char *argv[])
+{
+	struct mq_attr attr, result;
+
+	if (argc != 2) {
+		fprintf(stderr, "Must pass a valid queue name\n\n");
+		fprintf(stderr, usage, argv[0]);
+		exit(1);
+	}
+
+	/*
+	 * Although we can create a msg queue with a non-absolute path name,
+	 * unlink will fail.  So, if the name doesn't start with a /, add one
+	 * when we save it.
+	 */
+	if (*argv[1] == '/')
+		queue_path = strdup(argv[1]);
+	else {
+		queue_path = malloc(strlen(argv[1]) + 2);
+		if (!queue_path) {
+			perror("malloc()");
+			exit(1);
+		}
+		queue_path[0] = '/';
+		queue_path[1] = 0;
+		strcat(queue_path, argv[1]);
+	}
+
+	if (getuid() != 0) {
+		fprintf(stderr, "Not running as root, but almost all tests "
+			"require root in order to modify\nsystem settings.  "
+			"Exiting.\n");
+		exit(1);
+	}
+
+	/* Find out what files there are for us to make tweaks in */
+	def_msgs = fopen(DEF_MSGS, "r+");
+	def_msgsize = fopen(DEF_MSGSIZE, "r+");
+	max_msgs = fopen(MAX_MSGS, "r+");
+	max_msgsize = fopen(MAX_MSGSIZE, "r+");
+
+	if (!max_msgs)
+		shutdown(2, "Failed to open msg_max", __LINE__);
+	if (!max_msgsize)
+		shutdown(2, "Failed to open msgsize_max", __LINE__);
+	if (def_msgs || def_msgsize)
+		default_settings = 1;
+
+	/* Load up the current system values for everything we can */
+	getr(RLIMIT_MSGQUEUE, &saved_limits);
+	cur_limits = saved_limits;
+	if (default_settings) {
+		saved_def_msgs = cur_def_msgs = get(def_msgs);
+		saved_def_msgsize = cur_def_msgsize = get(def_msgsize);
+	}
+	saved_max_msgs = cur_max_msgs = get(max_msgs);
+	saved_max_msgsize = cur_max_msgsize = get(max_msgsize);
+
+	/* Tell the user our initial state */
+	printf("\nInitial system state:\n");
+	printf("\tUsing queue path:\t\t%s\n", queue_path);
+	printf("\tRLIMIT_MSGQUEUE(soft):\t\t%d\n", saved_limits.rlim_cur);
+	printf("\tRLIMIT_MSGQUEUE(hard):\t\t%d\n", saved_limits.rlim_max);
+	printf("\tMaximum Message Size:\t\t%d\n", saved_max_msgsize);
+	printf("\tMaximum Queue Size:\t\t%d\n", saved_max_msgs);
+	if (default_settings) {
+		printf("\tDefault Message Size:\t\t%d\n", saved_def_msgsize);
+		printf("\tDefault Queue Size:\t\t%d\n", saved_def_msgs);
+	} else {
+		printf("\tDefault Message Size:\t\tNot Supported\n");
+		printf("\tDefault Queue Size:\t\tNot Supported\n");
+	}
+	printf("\n");
+
+	validate_current_settings();
+
+	printf("Adjusted system state for testing:\n");
+	printf("\tRLIMIT_MSGQUEUE(soft):\t\t%d\n", cur_limits.rlim_cur);
+	printf("\tRLIMIT_MSGQUEUE(hard):\t\t%d\n", cur_limits.rlim_max);
+	printf("\tMaximum Message Size:\t\t%d\n", cur_max_msgsize);
+	printf("\tMaximum Queue Size:\t\t%d\n", cur_max_msgs);
+	if (default_settings) {
+		printf("\tDefault Message Size:\t\t%d\n", cur_def_msgsize);
+		printf("\tDefault Queue Size:\t\t%d\n", cur_def_msgs);
+	}
+
+	printf("\n\nTest series 1, behavior when no attr struct "
+	       "passed to mq_open:\n");
+	if (!default_settings) {
+		test_queue(NULL, &result);
+		printf("Given sane system settings, mq_open without an attr "
+		       "struct succeeds:\tPASS\n");
+		if (result.mq_maxmsg != cur_max_msgs ||
+		    result.mq_msgsize != cur_max_msgsize) {
+			printf("Kernel does not support setting the default "
+			       "mq attributes,\nbut also doesn't tie the "
+			       "defaults to the maximums:\t\t\tPASS\n");
+		} else {
+			set(max_msgs, ++cur_max_msgs);
+			set(max_msgsize, ++cur_max_msgsize);
+			test_queue(NULL, &result);
+			if (result.mq_maxmsg == cur_max_msgs &&
+			    result.mq_msgsize == cur_max_msgsize)
+				printf("Kernel does not support setting the "
+				       "default mq attributes and\n"
+				       "also ties system wide defaults to "
+				       "the system wide maximums:\t\t"
+				       "FAIL\n");
+			else
+				printf("Kernel does not support setting the "
+				       "default mq attributes,\n"
+				       "but also doesn't tie the defaults to "
+				       "the maximums:\t\t\tPASS\n");
+		}
+	} else {
+		printf("Kernel supports setting defaults separately from "
+		       "maximums:\t\tPASS\n");
+		/*
+		 * While we are here, go ahead and test that the kernel
+		 * properly follows the default settings
+		 */
+		test_queue(NULL, &result);
+		printf("Given sane values, mq_open without an attr struct "
+		       "succeeds:\t\tPASS\n");
+		if (result.mq_maxmsg != cur_def_msgs ||
+		    result.mq_msgsize != cur_def_msgsize)
+			printf("Kernel supports setting defaults, but does "
+			       "not actually honor them:\tFAIL\n\n");
+		else {
+			set(def_msgs, ++cur_def_msgs);
+			set(def_msgsize, ++cur_def_msgsize);
+			/* In case max was the same as the default */
+			set(max_msgs, ++cur_max_msgs);
+			set(max_msgsize, ++cur_max_msgsize);
+			test_queue(NULL, &result);
+			if (result.mq_maxmsg != cur_def_msgs ||
+			    result.mq_msgsize != cur_def_msgsize)
+				printf("Kernel supports setting defaults, but "
+				       "does not actually honor them:\t"
+				       "FAIL\n");
+			else
+				printf("Kernel properly honors default setting "
+				       "knobs:\t\t\t\tPASS\n");
+		}
+		set(def_msgs, cur_max_msgs + 1);
+		cur_def_msgs = cur_max_msgs + 1;
+		set(def_msgsize, cur_max_msgsize + 1);
+		cur_def_msgsize = cur_max_msgsize + 1;
+		if (cur_def_msgs * (cur_def_msgsize + 2 * sizeof(void *)) >=
+		    cur_limits.rlim_cur) {
+			cur_limits.rlim_cur = (cur_def_msgs + 2) *
+				(cur_def_msgsize + 2 * sizeof(void *));
+			cur_limits.rlim_max = 2 * cur_limits.rlim_cur;
+			setr(RLIMIT_MSGQUEUE, &cur_limits);
+		}
+		if (test_queue_fail(NULL, &result)) {
+			if (result.mq_maxmsg == cur_max_msgs &&
+			    result.mq_msgsize == cur_max_msgsize)
+				printf("Kernel properly limits default values "
+				       "to lesser of default/max:\t\tPASS\n");
+			else
+				printf("Kernel does not properly set default "
+				       "queue parameters when\ndefaults > "
+				       "max:\t\t\t\t\t\t\t\tFAIL\n");
+		} else
+			printf("Kernel fails to open mq because defaults are "
+			       "greater than maximums:\tFAIL\n");
+		set(def_msgs, --cur_def_msgs);
+		set(def_msgsize, --cur_def_msgsize);
+		cur_limits.rlim_cur = cur_limits.rlim_max = cur_def_msgs *
+			cur_def_msgsize;
+		setr(RLIMIT_MSGQUEUE, &cur_limits);
+		if (test_queue_fail(NULL, &result))
+			printf("Kernel creates queue even though defaults "
+			       "would exceed\nrlimit setting:"
+			       "\t\t\t\t\t\t\t\tFAIL\n");
+		else
+			printf("Kernel properly fails to create queue when "
+			       "defaults would\nexceed rlimit:"
+			       "\t\t\t\t\t\t\t\tPASS\n");
+	}
+
+	/*
+	 * Test #2 - open with an attr struct that exceeds rlimit
+	 */
+	printf("\n\nTest series 2, behavior when attr struct is "
+	       "passed to mq_open:\n");
+	cur_max_msgs = 32;
+	cur_max_msgsize = cur_limits.rlim_max >> 4;
+	set(max_msgs, cur_max_msgs);
+	set(max_msgsize, cur_max_msgsize);
+	attr.mq_maxmsg = cur_max_msgs;
+	attr.mq_msgsize = cur_max_msgsize;
+	if (test_queue_fail(&attr, &result))
+		printf("Queue open in excess of rlimit max when euid = 0 "
+		       "succeeded:\t\tFAIL\n");
+	else
+		printf("Queue open in excess of rlimit max when euid = 0 "
+		       "failed:\t\tPASS\n");
+	attr.mq_maxmsg = cur_max_msgs + 1;
+	attr.mq_msgsize = 10;
+	if (test_queue_fail(&attr, &result))
+		printf("Queue open with mq_maxmsg > limit when euid = 0 "
+		       "succeeded:\t\tPASS\n");
+	else
+		printf("Queue open with mq_maxmsg > limit when euid = 0 "
+		       "failed:\t\tFAIL\n");
+	attr.mq_maxmsg = 1;
+	attr.mq_msgsize = cur_max_msgsize + 1;
+	if (test_queue_fail(&attr, &result))
+		printf("Queue open with mq_msgsize > limit when euid = 0 "
+		       "succeeded:\t\tPASS\n");
+	else
+		printf("Queue open with mq_msgsize > limit when euid = 0 "
+		       "failed:\t\tFAIL\n");
+	attr.mq_maxmsg = 65536;
+	attr.mq_msgsize = 65536;
+	if (test_queue_fail(&attr, &result))
+		printf("Queue open with total size > 2GB when euid = 0 "
+		       "succeeded:\t\tFAIL\n");
+	else
+		printf("Queue open with total size > 2GB when euid = 0 "
+		       "failed:\t\t\tPASS\n");
+	seteuid(99);
+	attr.mq_maxmsg = cur_max_msgs;
+	attr.mq_msgsize = cur_max_msgsize;
+	if (test_queue_fail(&attr, &result))
+		printf("Queue open in excess of rlimit max when euid = 99 "
+		       "succeeded:\t\tFAIL\n");
+	else
+		printf("Queue open in excess of rlimit max when euid = 99 "
+		       "failed:\t\tPASS\n");
+	attr.mq_maxmsg = cur_max_msgs + 1;
+	attr.mq_msgsize = 10;
+	if (test_queue_fail(&attr, &result))
+		printf("Queue open with mq_maxmsg > limit when euid = 99 "
+		       "succeeded:\t\tFAIL\n");
+	else
+		printf("Queue open with mq_maxmsg > limit when euid = 99 "
+		       "failed:\t\tPASS\n");
+	attr.mq_maxmsg = 1;
+	attr.mq_msgsize = cur_max_msgsize + 1;
+	if (test_queue_fail(&attr, &result))
+		printf("Queue open with mq_msgsize > limit when euid = 99 "
+		       "succeeded:\t\tFAIL\n");
+	else
+		printf("Queue open with mq_msgsize > limit when euid = 99 "
+		       "failed:\t\tPASS\n");
+	attr.mq_maxmsg = 65536;
+	attr.mq_msgsize = 65536;
+	if (test_queue_fail(&attr, &result))
+		printf("Queue open with total size > 2GB when euid = 99 "
+		       "succeeded:\t\tFAIL\n");
+	else
+		printf("Queue open with total size > 2GB when euid = 99 "
+		       "failed:\t\t\tPASS\n");
+
+	shutdown(0,"",0);
+}