[PATCH lttng-tools v4 1/8] Fix: lttng_poll_mod calls compat_(e)poll_add

[PATCH lttng-tools v4 1/8] Fix: lttng_poll_mod calls compat_(e)poll_add

[Yannick Lamarre]

lttng_poll_mod should call compat_(e)poll_mod.

Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
---
 src/common/compat/poll.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/common/compat/poll.h b/src/common/compat/poll.h
index d4bd87f5..fde54ddb 100644
--- a/src/common/compat/poll.h
+++ b/src/common/compat/poll.h
@@ -177,7 +177,7 @@ extern int compat_epoll_del(struct lttng_poll_event *events, int fd);
 extern int compat_epoll_mod(struct lttng_poll_event *events,
 		int fd, uint32_t req_events);
 #define lttng_poll_mod(events, fd, req_events) \
-	compat_epoll_add(events, fd, req_events)
+	compat_epoll_mod(events, fd, req_events)
 
 /*
  * Set up the poll set limits variable poll_max_size
@@ -361,7 +361,7 @@ extern int compat_poll_del(struct lttng_poll_event *events, int fd);
 extern int compat_poll_mod(struct lttng_poll_event *events,
 		int fd, uint32_t req_events);
 #define lttng_poll_mod(events, fd, req_events) \
-	compat_poll_add(events, fd, req_events)
+	compat_poll_mod(events, fd, req_events)
 
 /*
  * Set up the poll set limits variable poll_max_size
-- 
2.11.0

[PATCH lttng-tools v4 2/8] Add Unit test to poll compatibility layer

[Yannick Lamarre]

Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
---
 .gitignore                          |   1 +
 tests/unit/Makefile.am              |   9 +-
 tests/unit/test_utils_compat_poll.c | 236 ++++++++++++++++++++++++++++++++++++
 3 files changed, 245 insertions(+), 1 deletion(-)
 create mode 100644 tests/unit/test_utils_compat_poll.c

diff --git a/.gitignore b/.gitignore
index 19276012..b5d2a55a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -73,6 +73,7 @@ TAGS
 /tests/unit/test_session
 /tests/unit/test_uri
 /tests/unit/test_ust_data
+/tests/unit/test_utils_compat_poll
 /tests/unit/test_utils_parse_size_suffix
 /tests/unit/test_utils_parse_time_suffix
 /tests/unit/test_utils_expand_path
diff --git a/tests/unit/Makefile.am b/tests/unit/Makefile.am
index 5f485f00..bcda6a5c 100644
--- a/tests/unit/Makefile.am
+++ b/tests/unit/Makefile.am
@@ -12,6 +12,7 @@ TESTS = test_kernel_data \
 	test_utils_parse_size_suffix \
 	test_utils_parse_time_suffix \
 	test_utils_expand_path \
+	test_utils_compat_poll \
 	test_string_utils \
 	test_notification \
 	ini_config/test_ini_config
@@ -28,7 +29,8 @@ LIBLTTNG_CTL=$(top_builddir)/src/lib/lttng-ctl/liblttng-ctl.la
 # Define test programs
 noinst_PROGRAMS = test_uri test_session test_kernel_data \
                   test_utils_parse_size_suffix test_utils_parse_time_suffix \
-                  test_utils_expand_path test_string_utils test_notification
+                  test_utils_expand_path test_utils_compat_poll \
+		  test_string_utils test_notification
 
 if HAVE_LIBLTTNG_UST_CTL
 noinst_PROGRAMS += test_ust_data
@@ -145,6 +147,11 @@ test_utils_parse_size_suffix_LDADD = $(LIBTAP) $(LIBHASHTABLE) $(LIBCOMMON) $(DL
 test_utils_parse_time_suffix_SOURCES = test_utils_parse_time_suffix.c
 test_utils_parse_time_suffix_LDADD = $(LIBTAP) $(LIBHASHTABLE) $(LIBCOMMON)
 
+# compat_poll unit test
+test_utils_compat_poll_SOURCES = test_utils_compat_poll.c
+test_utils_compat_poll_LDADD  = $(LIBTAP) $(LIBHASHTABLE) $(DL_LIBS) \
+		      $(top_builddir)/src/common/compat/libcompat.la $(LIBCOMMON)
+
 # expand_path unit test
 test_utils_expand_path_SOURCES = test_utils_expand_path.c
 test_utils_expand_path_LDADD = $(LIBTAP) $(LIBHASHTABLE) $(LIBCOMMON) $(DL_LIBS)
diff --git a/tests/unit/test_utils_compat_poll.c b/tests/unit/test_utils_compat_poll.c
new file mode 100644
index 00000000..f2c49254
--- /dev/null
+++ b/tests/unit/test_utils_compat_poll.c
@@ -0,0 +1,236 @@
+/*
+ * test_utils_compat_poll.c
+ *
+ * Unit tests for the compatibility layer of poll/epoll API.
+ *
+ * Copyright (C) 2019 Yannick Lamarre <ylamarre@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by as
+ * published by the Free Software Foundation; only version 2 of the License.
+ *
+ * This program 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.
+ */
+
+#include <assert.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <tap/tap.h>
+
+#include <common/compat/poll.h>
+#include <common/readwrite.h>
+
+/* Verification without trashing test order in the child process */
+#define childok(e, test, ...) do { \
+	if (!(e)) { \
+		diag(test, ## __VA_ARGS__); \
+		_exit(EXIT_FAILURE); \
+	} \
+} while(0)
+
+/* For error.h */
+int lttng_opt_quiet = 1;
+int lttng_opt_verbose;
+int lttng_opt_mi;
+
+#ifdef HAVE_EPOLL
+#define NUM_TESTS 46
+#else
+#define NUM_TESTS 45
+#endif
+
+#ifdef HAVE_EPOLL
+#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
+#define CLOE_VALUE EPOLL_CLOEXEC
+#else
+#define CLOE_VALUE FD_CLOEXEC
+#endif
+
+/* Non-zero 8-bits arbitrary value below 0x7f to ensure no sign extension
+ * used to verify that the value is properly propagated throught the pipe.
+ */
+#define MAGIC_VALUE ((char)0x5A)
+
+void test_epoll_compat(void)
+{
+	/*
+	 * Type conversion present to disable warning of anonymous enum from
+	 * compiler.
+	 */
+	ok((int)LTTNG_CLOEXEC == (int)CLOE_VALUE, "epoll's CLOEXEC value");
+}
+#endif
+
+void test_alloc(void)
+{
+	struct lttng_poll_event poll_events;
+
+	lttng_poll_init(&poll_events);
+
+	/* Null pointer */
+	ok(lttng_poll_create(NULL, 1, 0) != 0, "Create over NULL pointer fails");
+	/* Size 0 */
+	ok(lttng_poll_create(&poll_events, 0, 0) != 0, "Create with size 0 fails");
+	/* without CLOEXEC */
+	ok(lttng_poll_create(&poll_events, 1, 0) == 0, "Create valid poll set succeeds");
+	/*
+	 * lttng_poll_event structure untested due to incompatibility across
+	 * sublayers. lttng_poll_clean cannot be tested. There is no success
+	 * criteria. Verify set's max size cases.
+	 */
+	lttng_poll_clean(&poll_events);
+}
+
+/* Tests stuff related to what would be handled with epoll_ctl. */
+void test_add_del(void)
+{
+	struct lttng_poll_event poll_events;
+
+	lttng_poll_init(&poll_events);
+	ok(lttng_poll_add(NULL, 1, LPOLLIN) != 0, "Adding to NULL set fails");
+	ok(lttng_poll_add(&poll_events, 1, LPOLLIN) != 0, "Adding to uninitialized structure fails");
+	ok(lttng_poll_add(&poll_events, -1, LPOLLIN) != 0, "Adding invalid FD fails");
+
+	lttng_poll_create(&poll_events, 1, 0);
+	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Set created empty");
+
+	ok(lttng_poll_add(NULL, 1, LPOLLIN) != 0, "Adding to NULL set fails");
+	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Set still empty");
+	ok(lttng_poll_add(&poll_events, -1, LPOLLIN) != 0, "Adding invalid FD fails");
+	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Set still empty");
+
+	ok(lttng_poll_add(&poll_events, 1, LPOLLIN) == 0, "Adding valid FD succeeds");
+	ok(LTTNG_POLL_GETNB(&poll_events) == 1, "Nb of elements incremented");
+
+	ok(lttng_poll_del(NULL, 1) != 0, "Removing from NULL set fails");
+	ok(LTTNG_POLL_GETNB(&poll_events) == 1, "Number of FD in set unchanged");
+
+	ok(lttng_poll_del(&poll_events, -1) != 0, "Removing from negative FD fails");
+	ok(LTTNG_POLL_GETNB(&poll_events) == 1, "Number of FD in set unchanged");
+
+	ok(lttng_poll_del(&poll_events, 2) == 0, "Removing invalid FD still succeeds");
+	ok(LTTNG_POLL_GETNB(&poll_events) == 1, "Number of elements unchanged");
+
+	ok(lttng_poll_del(&poll_events, 1) == 0, "Removing valid FD succeeds");
+	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Nb of elements decremented");
+
+	ok(lttng_poll_del(&poll_events, 1) != 0, "Removing from empty set fails");
+	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Nb of elements unchanged");
+
+	lttng_poll_clean(&poll_events);
+}
+
+void test_mod_wait(void)
+{
+	struct lttng_poll_event poll_events;
+	struct lttng_poll_event cpoll_events;
+
+	int hupfd[2];
+	int infd[2];
+	pid_t cpid;
+	char rbuf = 0, tbuf = MAGIC_VALUE;
+	int wstatus;
+
+	lttng_poll_init(&poll_events);
+	lttng_poll_init(&cpoll_events);
+
+	ok(pipe(hupfd) != -1);
+	ok(pipe(infd) != -1);
+
+	cpid = fork();
+	if (cpid == 0) {
+		childok(lttng_poll_create(&cpoll_events, 1, 0) == 0, "Create valid poll set succeeds");
+		childok(lttng_poll_mod(NULL, infd[0], LPOLLIN) == -1, "lttng_poll_mod with invalid input returns an error");
+		childok(lttng_poll_mod(&cpoll_events, infd[0], LPOLLIN) == -1, "lttng_poll_mod with invalid input returns an error");
+		childok(lttng_poll_add(&cpoll_events, infd[0], LPOLLHUP) == 0, "Add valid FD succeeds");
+		childok(lttng_poll_mod(&cpoll_events, -1, LPOLLIN) == -1, "lttng_poll_mod with invalid input returns an error");
+		childok(lttng_poll_mod(&cpoll_events, hupfd[0], LPOLLIN) == 0, "lttng_poll_mod on unincluded FD goes on");
+		childok(lttng_poll_mod(&cpoll_events, infd[0], LPOLLIN) == 0, "Modify event type succeeds");
+		childok(close(infd[1]) == 0, "Close valid FD succeeds");
+		childok(lttng_poll_wait(&cpoll_events, -1) == 1, "Wait on close times out");
+		childok(lttng_read(infd[0], &rbuf, 1) == 1, "Data is present in the pipe");
+		childok(rbuf == MAGIC_VALUE, "Received data is consistent with transmitted data");
+		childok(lttng_poll_del(&cpoll_events, infd[0]) == 0, "Removing valid FD succeeds");
+		childok(close(infd[0]) == 0, "Close valid FD succeeds");
+		childok(close(hupfd[0]) == 0, "Close valid FD succeeds");
+		childok(close(hupfd[1]) == 0, "Close valid FD succeeds");
+		lttng_poll_clean(&cpoll_events);
+		_exit(EXIT_SUCCESS);
+	} else {
+		ok(close(hupfd[1]) == 0, "Close valid FD succeeds");
+		ok(close(infd[0]) == 0, "Close valid FD succeeds");
+
+		ok(lttng_poll_wait(NULL, -1) == -1, "lttng_poll_wait call with invalid input returns error");
+
+		ok(lttng_poll_create(&poll_events, 1, 0) == 0, "Create valid poll set succeeds");
+		ok(lttng_poll_wait(&poll_events, -1) == -1, "lttng_poll_wait call with invalid input returns error");
+		ok(lttng_poll_add(&poll_events, hupfd[0], LPOLLHUP) == 0, "Add valid FD succeeds");
+		ok(lttng_write(infd[1], &tbuf, 1) == 1, "Write to pipe succeeds");
+		ok(lttng_poll_wait(&poll_events, -1) == 1, "Wakes up on one event");
+		ok(lttng_poll_del(&poll_events, hupfd[0]) == 0, "Removing valid FD succeeds");
+		ok(close(hupfd[0]) == 0, "Close valid FD succeeds");
+		ok(close(infd[1]) == 0, "Close valid FD succeeds");
+		lttng_poll_clean(&poll_events);
+
+		ok(waitpid(cpid, &wstatus, 0) == cpid, "waitpid returns child's pid");
+		ok(WIFEXITED(wstatus) == 1, "Child process exited");
+		ok(WEXITSTATUS(wstatus) == (EXIT_SUCCESS & 0xff), "EXIT_SUCCESS is %i while exit status is %i\n", EXIT_SUCCESS, WEXITSTATUS(wstatus));
+	}
+
+}
+
+void test_func_def(void)
+{
+#ifdef LTTNG_POLL_GETFD
+#define PASS_GETFD 1
+#else
+#define PASS_GETFD 0
+#endif
+
+#ifdef LTTNG_POLL_GETEV
+#define PASS_GETEV 1
+#else
+#define PASS_GETEV 0
+#endif
+
+#ifdef LTTNG_POLL_GETSZ
+#define PASS_GETSZ 1
+#else
+#define PASS_GETSZ 0
+#endif
+
+#ifdef LTTNG_POLL_GET_PREV_FD
+#define PASS_GET_PREV_FD 1
+#else
+#define PASS_GET_PREV_FD 0
+#endif
+
+	ok(lttng_poll_reset == lttng_poll_reset, "lttng_poll_reset is defined");
+	ok(lttng_poll_init == lttng_poll_init , "lttng_poll_reset is defined");
+	ok(PASS_GETFD, "GETFD is defined");
+	ok(PASS_GETEV, "GETEV is defined");
+	ok(PASS_GETSZ, "GETSZ is defined");
+	ok(PASS_GET_PREV_FD, "GET_PREV_FD is defined");
+
+}
+
+int main(void)
+{
+	plan_tests(NUM_TESTS);
+#ifdef HAVE_EPOLL
+	test_epoll_compat();
+#endif
+	test_func_def();
+	test_alloc();
+	test_add_del();
+	test_mod_wait();
+	return exit_status();
+}
-- 
2.11.0

[PATCH lttng-tools v4 3/8] Change LTTNG_POLL_GETNB behaviour for poll flavor

[Yannick Lamarre]

Modify LTTNG_POLL_GETNB to provide compatibility with the epoll flavor.
Since it is only used after a lttng_poll_wait call with no modification
(add, del, mod) between, this change does not modify the behaviour in
its current usage while ensuring similar API behavior between
compatibility layer implementations.

Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
---
 src/common/compat/poll.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/common/compat/poll.h b/src/common/compat/poll.h
index fde54ddb..5eb7ff9c 100644
--- a/src/common/compat/poll.h
+++ b/src/common/compat/poll.h
@@ -315,10 +315,12 @@ static inline int __lttng_poll_get_prev_fd(struct lttng_poll_event *events,
 /*
  * For the following calls, consider 'e' to be a lttng_poll_event pointer and i
  * being the index of the events array.
+ * LTTNG_POLL_GETNB is always used after lttng_poll_wait, thus we can use the
+ * current list for test compatibility purposes.
  */
 #define LTTNG_POLL_GETFD(e, i) LTTNG_REF(e)->wait.events[i].fd
 #define LTTNG_POLL_GETEV(e, i) LTTNG_REF(e)->wait.events[i].revents
-#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->wait.nb_fd
+#define LTTNG_POLL_GETNB(e) LTTNG_REF(e)->current.nb_fd
 #define LTTNG_POLL_GETSZ(e) LTTNG_REF(e)->wait.events_size
 #define LTTNG_POLL_GET_PREV_FD(e, i, nb_fd) \
 	__lttng_poll_get_prev_fd(LTTNG_REF(e), i, nb_fd)
-- 
2.11.0

[PATCH lttng-tools v4 4/8] Adapt poll layer behaviour to match the epoll layer

[Yannick Lamarre]

Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
---
 src/common/compat/compat-poll.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c
index b45b39dc..be655728 100644
--- a/src/common/compat/compat-poll.c
+++ b/src/common/compat/compat-poll.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C)  2019 - Yannick Lamarre <ylamarre@efficios.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License, version 2 only,
@@ -204,10 +205,10 @@ int compat_poll_mod(struct lttng_poll_event *events, int fd,
 		uint32_t req_events)
 {
 	int i;
-	bool fd_found = false;
 	struct compat_poll_event_array *current;
 
-	if (events == NULL || events->current.events == NULL || fd < 0) {
+	if (events == NULL || events->current.nb_fd == 0 ||
+			events->current.events == NULL || fd < 0) {
 		ERR("Bad compat poll mod arguments");
 		goto error;
 	}
@@ -216,16 +217,16 @@ int compat_poll_mod(struct lttng_poll_event *events, int fd,
 
 	for (i = 0; i < current->nb_fd; i++) {
 		if (current->events[i].fd == fd) {
-			fd_found = true;
 			current->events[i].events = req_events;
 			events->need_update = 1;
 			break;
 		}
 	}
 
-	if (!fd_found) {
-		goto error;
-	}
+	/* 
+	 * The epoll flavor doesn't flag modifying a non-included FD as an
+	 * error.
+	 */
 
 	return 0;
 
@@ -238,11 +239,12 @@ error:
  */
 int compat_poll_del(struct lttng_poll_event *events, int fd)
 {
-	int new_size, i, count = 0, ret;
+	int i, count = 0, ret;
+	uint32_t new_size;
 	struct compat_poll_event_array *current;
 
-	if (events == NULL || events->current.events == NULL || fd < 0) {
-		ERR("Wrong arguments for poll del");
+	if (events == NULL || events->current.nb_fd == 0 ||
+			events->current.events == NULL || fd < 0) {
 		goto error;
 	}
 
@@ -257,13 +259,20 @@ int compat_poll_del(struct lttng_poll_event *events, int fd)
 			count++;
 		}
 	}
+
+	/* The fd was not in our set, return no error as with epoll. */
+	if (current->nb_fd == count) {
+		goto end;
+	}
+
 	/* No fd duplicate should be ever added into array. */
 	assert(current->nb_fd - 1 == count);
 	current->nb_fd = count;
 
 	/* Resize array if needed. */
 	new_size = 1U << utils_get_count_order_u32(current->nb_fd);
-	if (new_size != current->alloc_size && new_size >= current->init_size) {
+	if (new_size != current->alloc_size && new_size >= current->init_size
+			&& current->nb_fd != 0) {
 		ret = resize_poll_event(current, new_size);
 		if (ret < 0) {
 			goto error;
@@ -272,6 +281,7 @@ int compat_poll_del(struct lttng_poll_event *events, int fd)
 
 	events->need_update = 1;
 
+end:
 	return 0;
 
 error:
-- 
2.11.0

[PATCH lttng-tools v4 5/8] Fix hang in thread_rotation when using compat-poll

[Yannick Lamarre]

Add missing verification to prevent a blocking read on an empty fd.

Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
---
 src/bin/lttng-sessiond/rotation-thread.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/bin/lttng-sessiond/rotation-thread.c b/src/bin/lttng-sessiond/rotation-thread.c
index 6669372d..b86b1668 100644
--- a/src/bin/lttng-sessiond/rotation-thread.c
+++ b/src/bin/lttng-sessiond/rotation-thread.c
@@ -974,6 +974,10 @@ void *thread_rotation(void *data)
 			int fd = LTTNG_POLL_GETFD(&thread.events, i);
 			uint32_t revents = LTTNG_POLL_GETEV(&thread.events, i);
 
+			if (!revents) {
+				/* No activity for this FD (poll implementation). */
+				continue;
+			}
 			DBG("[rotation-thread] Handling fd (%i) activity (%u)",
 					fd, revents);
 
-- 
2.11.0

[PATCH lttng-tools v4 6/8] Change lttng_poll_wait behaviour of compat-poll to match compat-epoll

[Yannick Lamarre]

This removes the need to verify for idle file descriptors and mitigates
risks of bug due to behaviour mismatch.

Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
---

The assert in the for loop is removed.

 src/common/compat/compat-poll.c | 37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c
index be655728..5b752a28 100644
--- a/src/common/compat/compat-poll.c
+++ b/src/common/compat/compat-poll.c
@@ -293,7 +293,8 @@ error:
  */
 int compat_poll_wait(struct lttng_poll_event *events, int timeout)
 {
-	int ret;
+	int ret, active_fd_count;
+	int idle_pfd_index = 0;
 
 	if (events == NULL || events->current.events == NULL) {
 		ERR("poll wait arguments error");
@@ -325,11 +326,39 @@ int compat_poll_wait(struct lttng_poll_event *events, int timeout)
 		goto error;
 	}
 
+	active_fd_count = ret;
+
 	/*
-	 * poll() should always iterate on all FDs since we handle the pollset in
-	 * user space and after poll returns, we have to try every fd for a match.
+	 * Swap all active pollfd structs to the beginning of the
+	 * array to emulate compat-epoll behaviour. This algorithm takes
+	 * advantage of poll's returned value and the burst nature of active
+	 * events on the file descriptors. The while loop guarantees that
+	 * idle_pfd will always point to an idle fd.
 	 */
-	return events->wait.nb_fd;
+	if (active_fd_count == events->wait.nb_fd) {
+		goto end;
+	}
+	while (idle_pfd_index < active_fd_count &&
+			events->wait.events[idle_pfd_index].revents != 0) {
+		idle_pfd_index++;
+	}
+
+	for (int i = idle_pfd_index + 1; idle_pfd_index < active_fd_count;
+			i++) {
+		struct pollfd swap_pfd;
+		struct pollfd *idle_pfd = &events->wait.events[idle_pfd_index];
+		struct pollfd *current_pfd = &events->wait.events[i];
+
+		if (ipfd->revents != 0) {
+			swap_pfd = *current_pfd;
+			*current_pfd = *idle_pfd;
+			*idle_pfd = swap_pfd;
+			idle_pfd_index++;
+		}
+	}
+
+end:
+	return ret;
 
 error:
 	return -1;
-- 
2.11.0

[PATCH lttng-tools v4 7/8] Clean code base from redundant verification

[Yannick Lamarre]

Remove redundant verification for file descriptors with 0 revents in
code base.

Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
---
 src/bin/lttng-consumerd/health-consumerd.c   |  5 -----
 src/bin/lttng-relayd/health-relayd.c         |  5 -----
 src/bin/lttng-relayd/live.c                  | 10 ----------
 src/bin/lttng-relayd/main.c                  | 16 ----------------
 src/bin/lttng-sessiond/agent-thread.c        |  5 -----
 src/bin/lttng-sessiond/client.c              |  5 -----
 src/bin/lttng-sessiond/dispatch.c            |  5 -----
 src/bin/lttng-sessiond/health.c              |  5 -----
 src/bin/lttng-sessiond/ht-cleanup.c          |  5 -----
 src/bin/lttng-sessiond/manage-apps.c         |  5 -----
 src/bin/lttng-sessiond/manage-consumer.c     | 10 ----------
 src/bin/lttng-sessiond/manage-kernel.c       |  5 -----
 src/bin/lttng-sessiond/notification-thread.c |  3 ---
 src/bin/lttng-sessiond/notify-apps.c         |  5 -----
 src/bin/lttng-sessiond/register.c            |  5 -----
 src/bin/lttng-sessiond/rotation-thread.c     |  4 ----
 src/common/consumer/consumer.c               | 10 ----------
 17 files changed, 108 deletions(-)

diff --git a/src/bin/lttng-consumerd/health-consumerd.c b/src/bin/lttng-consumerd/health-consumerd.c
index 1e2f31e4..7d60e54e 100644
--- a/src/bin/lttng-consumerd/health-consumerd.c
+++ b/src/bin/lttng-consumerd/health-consumerd.c
@@ -259,11 +259,6 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			/* Thread quit pipe has been closed. Killing thread. */
 			ret = check_health_quit_pipe(pollfd, revents);
 			if (ret) {
diff --git a/src/bin/lttng-relayd/health-relayd.c b/src/bin/lttng-relayd/health-relayd.c
index ba996621..b782c3e7 100644
--- a/src/bin/lttng-relayd/health-relayd.c
+++ b/src/bin/lttng-relayd/health-relayd.c
@@ -329,11 +329,6 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			/* Thread quit pipe has been closed. Killing thread. */
 			ret = check_health_quit_pipe(pollfd, revents);
 			if (ret) {
diff --git a/src/bin/lttng-relayd/live.c b/src/bin/lttng-relayd/live.c
index 9efab8a7..9503ba47 100644
--- a/src/bin/lttng-relayd/live.c
+++ b/src/bin/lttng-relayd/live.c
@@ -543,11 +543,6 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			/* Thread quit pipe has been closed. Killing thread. */
 			ret = check_thread_quit_pipe(pollfd, revents);
 			if (ret) {
@@ -2000,11 +1995,6 @@ restart:
 
 			health_code_update();
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			/* Thread quit pipe has been closed. Killing thread. */
 			ret = check_thread_quit_pipe(pollfd, revents);
 			if (ret) {
diff --git a/src/bin/lttng-relayd/main.c b/src/bin/lttng-relayd/main.c
index e81bdeff..0ee27efc 100644
--- a/src/bin/lttng-relayd/main.c
+++ b/src/bin/lttng-relayd/main.c
@@ -858,14 +858,6 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/*
-				 * No activity for this FD (poll
-				 * implementation).
-				 */
-				continue;
-			}
-
 			/* Thread quit pipe has been closed. Killing thread. */
 			ret = check_thread_quit_pipe(pollfd, revents);
 			if (ret) {
@@ -3813,14 +3805,6 @@ restart:
 
 			health_code_update();
 
-			if (!revents) {
-				/*
-				 * No activity for this FD (poll
-				 * implementation).
-				 */
-				continue;
-			}
-
 			/* Thread quit pipe has been closed. Killing thread. */
 			ret = check_thread_quit_pipe(pollfd, revents);
 			if (ret) {
diff --git a/src/bin/lttng-sessiond/agent-thread.c b/src/bin/lttng-sessiond/agent-thread.c
index f7be1ef7..575f6aee 100644
--- a/src/bin/lttng-sessiond/agent-thread.c
+++ b/src/bin/lttng-sessiond/agent-thread.c
@@ -404,11 +404,6 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			/* Thread quit pipe has been closed. Killing thread. */
 			if (pollfd == quit_pipe_read_fd) {
 				goto exit;
diff --git a/src/bin/lttng-sessiond/client.c b/src/bin/lttng-sessiond/client.c
index a889529a..0be065ec 100644
--- a/src/bin/lttng-sessiond/client.c
+++ b/src/bin/lttng-sessiond/client.c
@@ -2174,11 +2174,6 @@ static void *thread_manage_clients(void *data)
 
 			health_code_update();
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			if (pollfd == thread_quit_pipe_fd) {
 				err = 0;
 				goto exit;
diff --git a/src/bin/lttng-sessiond/dispatch.c b/src/bin/lttng-sessiond/dispatch.c
index 04b3954c..a637f23d 100644
--- a/src/bin/lttng-sessiond/dispatch.c
+++ b/src/bin/lttng-sessiond/dispatch.c
@@ -144,11 +144,6 @@ static void sanitize_wait_queue(struct ust_reg_wait_queue *wait_queue)
 		uint32_t revents = LTTNG_POLL_GETEV(&events, i);
 		int pollfd = LTTNG_POLL_GETFD(&events, i);
 
-		if (!revents) {
-			/* No activity for this FD (poll implementation). */
-			continue;
-		}
-
 		cds_list_for_each_entry_safe(wait_node, tmp_wait_node,
 				&wait_queue->head, head) {
 			if (pollfd == wait_node->app->sock &&
diff --git a/src/bin/lttng-sessiond/health.c b/src/bin/lttng-sessiond/health.c
index 921b4526..5b4f5f8f 100644
--- a/src/bin/lttng-sessiond/health.c
+++ b/src/bin/lttng-sessiond/health.c
@@ -158,11 +158,6 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			/* Event on the registration socket */
 			if (pollfd == sock) {
 				if (revents & LPOLLIN) {
diff --git a/src/bin/lttng-sessiond/ht-cleanup.c b/src/bin/lttng-sessiond/ht-cleanup.c
index 91c0544c..02244f0c 100644
--- a/src/bin/lttng-sessiond/ht-cleanup.c
+++ b/src/bin/lttng-sessiond/ht-cleanup.c
@@ -155,11 +155,6 @@ static void *thread_ht_cleanup(void *data)
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			if (pollfd != ht_cleanup_pipe[0]) {
 				continue;
 			}
diff --git a/src/bin/lttng-sessiond/manage-apps.c b/src/bin/lttng-sessiond/manage-apps.c
index f9ec356d..356c147a 100644
--- a/src/bin/lttng-sessiond/manage-apps.c
+++ b/src/bin/lttng-sessiond/manage-apps.c
@@ -123,11 +123,6 @@ static void *thread_application_management(void *data)
 
 			health_code_update();
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			if (pollfd == quit_pipe_read_fd) {
 				err = 0;
 				goto exit;
diff --git a/src/bin/lttng-sessiond/manage-consumer.c b/src/bin/lttng-sessiond/manage-consumer.c
index b710c61f..fa802adc 100644
--- a/src/bin/lttng-sessiond/manage-consumer.c
+++ b/src/bin/lttng-sessiond/manage-consumer.c
@@ -134,11 +134,6 @@ void *thread_consumer_management(void *data)
 
 		health_code_update();
 
-		if (!revents) {
-			/* No activity for this FD (poll implementation). */
-			continue;
-		}
-
 		/* Thread quit pipe has been closed. Killing thread. */
 		if (pollfd == quit_pipe_read_fd) {
 			err = 0;
@@ -298,11 +293,6 @@ void *thread_consumer_management(void *data)
 
 			health_code_update();
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			/*
 			 * Thread quit pipe has been triggered, flag that we should stop
 			 * but continue the current loop to handle potential data from
diff --git a/src/bin/lttng-sessiond/manage-kernel.c b/src/bin/lttng-sessiond/manage-kernel.c
index 34887d7b..f656c9f5 100644
--- a/src/bin/lttng-sessiond/manage-kernel.c
+++ b/src/bin/lttng-sessiond/manage-kernel.c
@@ -267,11 +267,6 @@ static void *thread_kernel_management(void *data)
 
 			health_code_update();
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			if (pollfd == quit_pipe_read_fd) {
 				err = 0;
 				goto exit;
diff --git a/src/bin/lttng-sessiond/notification-thread.c b/src/bin/lttng-sessiond/notification-thread.c
index b42b282e..0a1fd557 100644
--- a/src/bin/lttng-sessiond/notification-thread.c
+++ b/src/bin/lttng-sessiond/notification-thread.c
@@ -562,9 +562,6 @@ void *thread_notification(void *data)
 			int fd = LTTNG_POLL_GETFD(&state.events, i);
 			uint32_t revents = LTTNG_POLL_GETEV(&state.events, i);
 
-			if (!revents) {
-				continue;
-			}
 			DBG("[notification-thread] Handling fd (%i) activity (%u)", fd, revents);
 
 			if (fd == state.notification_channel_socket) {
diff --git a/src/bin/lttng-sessiond/notify-apps.c b/src/bin/lttng-sessiond/notify-apps.c
index bc7405c7..17f3cd0c 100644
--- a/src/bin/lttng-sessiond/notify-apps.c
+++ b/src/bin/lttng-sessiond/notify-apps.c
@@ -109,11 +109,6 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			/* Thread quit pipe has been closed. Killing thread. */
 			if (pollfd == quit_pipe_read_fd) {
 				err = 0;
diff --git a/src/bin/lttng-sessiond/register.c b/src/bin/lttng-sessiond/register.c
index 6ce25ad0..e809834f 100644
--- a/src/bin/lttng-sessiond/register.c
+++ b/src/bin/lttng-sessiond/register.c
@@ -239,11 +239,6 @@ static void *thread_application_registration(void *data)
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			/* Thread quit pipe has been closed. Killing thread. */
 			if (pollfd == quit_pipe_read_fd) {
 				err = 0;
diff --git a/src/bin/lttng-sessiond/rotation-thread.c b/src/bin/lttng-sessiond/rotation-thread.c
index b86b1668..6669372d 100644
--- a/src/bin/lttng-sessiond/rotation-thread.c
+++ b/src/bin/lttng-sessiond/rotation-thread.c
@@ -974,10 +974,6 @@ void *thread_rotation(void *data)
 			int fd = LTTNG_POLL_GETFD(&thread.events, i);
 			uint32_t revents = LTTNG_POLL_GETEV(&thread.events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
 			DBG("[rotation-thread] Handling fd (%i) activity (%u)",
 					fd, revents);
 
diff --git a/src/common/consumer/consumer.c b/src/common/consumer/consumer.c
index 10273e66..c70d95a5 100644
--- a/src/common/consumer/consumer.c
+++ b/src/common/consumer/consumer.c
@@ -2396,11 +2396,6 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			if (pollfd == lttng_pipe_get_readfd(ctx->consumer_metadata_pipe)) {
 				if (revents & LPOLLIN) {
 					ssize_t pipe_len;
@@ -2990,11 +2985,6 @@ restart:
 			revents = LTTNG_POLL_GETEV(&events, i);
 			pollfd = LTTNG_POLL_GETFD(&events, i);
 
-			if (!revents) {
-				/* No activity for this FD (poll implementation). */
-				continue;
-			}
-
 			if (pollfd == ctx->consumer_channel_pipe[0]) {
 				if (revents & LPOLLIN) {
 					enum consumer_channel_action action;
-- 
2.11.0

[PATCH lttng-tools v4 8/8] Fix typo

[Yannick Lamarre]

Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
---
 src/common/compat/poll.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/common/compat/poll.h b/src/common/compat/poll.h
index 5eb7ff9c..d7020f36 100644
--- a/src/common/compat/poll.h
+++ b/src/common/compat/poll.h
@@ -358,7 +358,7 @@ extern int compat_poll_del(struct lttng_poll_event *events, int fd);
 	compat_poll_del(events, fd)
 
 /*
- * Modify an fd's events in the epoll set.
+ * Modify an fd's events in the poll set.
  */
 extern int compat_poll_mod(struct lttng_poll_event *events,
 		int fd, uint32_t req_events);
-- 
2.11.0

Re: [PATCH lttng-tools v4 2/8] Add Unit test to poll compatibility layer

[Jérémie Galarneau]

On Mon, Apr 01, 2019 at 01:59:19PM -0400, Yannick Lamarre wrote:
> Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
> ---
>  .gitignore                          |   1 +
>  tests/unit/Makefile.am              |   9 +-
>  tests/unit/test_utils_compat_poll.c | 236 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 245 insertions(+), 1 deletion(-)
>  create mode 100644 tests/unit/test_utils_compat_poll.c
> 
> diff --git a/.gitignore b/.gitignore
> index 19276012..b5d2a55a 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -73,6 +73,7 @@ TAGS
>  /tests/unit/test_session
>  /tests/unit/test_uri
>  /tests/unit/test_ust_data
> +/tests/unit/test_utils_compat_poll
>  /tests/unit/test_utils_parse_size_suffix
>  /tests/unit/test_utils_parse_time_suffix
>  /tests/unit/test_utils_expand_path
> diff --git a/tests/unit/Makefile.am b/tests/unit/Makefile.am
> index 5f485f00..bcda6a5c 100644
> --- a/tests/unit/Makefile.am
> +++ b/tests/unit/Makefile.am
> @@ -12,6 +12,7 @@ TESTS = test_kernel_data \
>  	test_utils_parse_size_suffix \
>  	test_utils_parse_time_suffix \
>  	test_utils_expand_path \
> +	test_utils_compat_poll \
>  	test_string_utils \
>  	test_notification \
>  	ini_config/test_ini_config
> @@ -28,7 +29,8 @@ LIBLTTNG_CTL=$(top_builddir)/src/lib/lttng-ctl/liblttng-ctl.la
>  # Define test programs
>  noinst_PROGRAMS = test_uri test_session test_kernel_data \
>                    test_utils_parse_size_suffix test_utils_parse_time_suffix \
> -                  test_utils_expand_path test_string_utils test_notification
> +                  test_utils_expand_path test_utils_compat_poll \
> +		  test_string_utils test_notification

Use spaces to indent here.

>  
>  if HAVE_LIBLTTNG_UST_CTL
>  noinst_PROGRAMS += test_ust_data
> @@ -145,6 +147,11 @@ test_utils_parse_size_suffix_LDADD = $(LIBTAP) $(LIBHASHTABLE) $(LIBCOMMON) $(DL
>  test_utils_parse_time_suffix_SOURCES = test_utils_parse_time_suffix.c
>  test_utils_parse_time_suffix_LDADD = $(LIBTAP) $(LIBHASHTABLE) $(LIBCOMMON)
>  
> +# compat_poll unit test
> +test_utils_compat_poll_SOURCES = test_utils_compat_poll.c
> +test_utils_compat_poll_LDADD  = $(LIBTAP) $(LIBHASHTABLE) $(DL_LIBS) \
> +		      $(top_builddir)/src/common/compat/libcompat.la $(LIBCOMMON)
> +
>  # expand_path unit test
>  test_utils_expand_path_SOURCES = test_utils_expand_path.c
>  test_utils_expand_path_LDADD = $(LIBTAP) $(LIBHASHTABLE) $(LIBCOMMON) $(DL_LIBS)
> diff --git a/tests/unit/test_utils_compat_poll.c b/tests/unit/test_utils_compat_poll.c
> new file mode 100644
> index 00000000..f2c49254
> --- /dev/null
> +++ b/tests/unit/test_utils_compat_poll.c
> @@ -0,0 +1,236 @@
> +/*
> + * test_utils_compat_poll.c
> + *
> + * Unit tests for the compatibility layer of poll/epoll API.
> + *
> + * Copyright (C) 2019 Yannick Lamarre <ylamarre@efficios.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by as
> + * published by the Free Software Foundation; only version 2 of the License.
> + *
> + * This program 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.
> + */
> +
> +#include <assert.h>
> +#include <inttypes.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <sys/types.h>
> +#include <sys/wait.h>
> +
> +#include <tap/tap.h>
> +
> +#include <common/compat/poll.h>
> +#include <common/readwrite.h>
> +
> +/* Verification without trashing test order in the child process */
> +#define childok(e, test, ...) do { \
> +	if (!(e)) { \
> +		diag(test, ## __VA_ARGS__); \
> +		_exit(EXIT_FAILURE); \
> +	} \
> +} while(0)
> +
> +/* For error.h */
> +int lttng_opt_quiet = 1;
> +int lttng_opt_verbose;
> +int lttng_opt_mi;
> +
> +#ifdef HAVE_EPOLL
> +#define NUM_TESTS 46
> +#else
> +#define NUM_TESTS 45
> +#endif
> +
> +#ifdef HAVE_EPOLL
> +#if defined(HAVE_EPOLL_CREATE1) && defined(EPOLL_CLOEXEC)
> +#define CLOE_VALUE EPOLL_CLOEXEC
> +#else
> +#define CLOE_VALUE FD_CLOEXEC
> +#endif
> +
> +/* Non-zero 8-bits arbitrary value below 0x7f to ensure no sign extension
> + * used to verify that the value is properly propagated throught the pipe.
> + */
> +#define MAGIC_VALUE ((char)0x5A)
> +
> +void test_epoll_compat(void)
> +{
> +	/*
> +	 * Type conversion present to disable warning of anonymous enum from
> +	 * compiler.
> +	 */
> +	ok((int)LTTNG_CLOEXEC == (int)CLOE_VALUE, "epoll's CLOEXEC value");

Put a space between operators and operands (cast and value).

> +}
> +#endif
> +
> +void test_alloc(void)
> +{
> +	struct lttng_poll_event poll_events;
> +
> +	lttng_poll_init(&poll_events);
> +
> +	/* Null pointer */
> +	ok(lttng_poll_create(NULL, 1, 0) != 0, "Create over NULL pointer fails");
> +	/* Size 0 */
> +	ok(lttng_poll_create(&poll_events, 0, 0) != 0, "Create with size 0 fails");
> +	/* without CLOEXEC */
> +	ok(lttng_poll_create(&poll_events, 1, 0) == 0, "Create valid poll set succeeds");
> +	/*
> +	 * lttng_poll_event structure untested due to incompatibility across
> +	 * sublayers. lttng_poll_clean cannot be tested. There is no success
> +	 * criteria. Verify set's max size cases.
> +	 */
> +	lttng_poll_clean(&poll_events);
> +}
> +
> +/* Tests stuff related to what would be handled with epoll_ctl. */
> +void test_add_del(void)
> +{
> +	struct lttng_poll_event poll_events;
> +
> +	lttng_poll_init(&poll_events);
> +	ok(lttng_poll_add(NULL, 1, LPOLLIN) != 0, "Adding to NULL set fails");
> +	ok(lttng_poll_add(&poll_events, 1, LPOLLIN) != 0, "Adding to uninitialized structure fails");
> +	ok(lttng_poll_add(&poll_events, -1, LPOLLIN) != 0, "Adding invalid FD fails");
> +
> +	lttng_poll_create(&poll_events, 1, 0);
> +	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Set created empty");
> +
> +	ok(lttng_poll_add(NULL, 1, LPOLLIN) != 0, "Adding to NULL set fails");
> +	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Set still empty");
> +	ok(lttng_poll_add(&poll_events, -1, LPOLLIN) != 0, "Adding invalid FD fails");
> +	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Set still empty");
> +
> +	ok(lttng_poll_add(&poll_events, 1, LPOLLIN) == 0, "Adding valid FD succeeds");
> +	ok(LTTNG_POLL_GETNB(&poll_events) == 1, "Nb of elements incremented");
> +
> +	ok(lttng_poll_del(NULL, 1) != 0, "Removing from NULL set fails");
> +	ok(LTTNG_POLL_GETNB(&poll_events) == 1, "Number of FD in set unchanged");
> +
> +	ok(lttng_poll_del(&poll_events, -1) != 0, "Removing from negative FD fails");
> +	ok(LTTNG_POLL_GETNB(&poll_events) == 1, "Number of FD in set unchanged");
> +
> +	ok(lttng_poll_del(&poll_events, 2) == 0, "Removing invalid FD still succeeds");
> +	ok(LTTNG_POLL_GETNB(&poll_events) == 1, "Number of elements unchanged");
> +
> +	ok(lttng_poll_del(&poll_events, 1) == 0, "Removing valid FD succeeds");
> +	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Nb of elements decremented");
> +
> +	ok(lttng_poll_del(&poll_events, 1) != 0, "Removing from empty set fails");
> +	ok(LTTNG_POLL_GETNB(&poll_events) == 0, "Nb of elements unchanged");
> +
> +	lttng_poll_clean(&poll_events);
> +}
> +
> +void test_mod_wait(void)
> +{
> +	struct lttng_poll_event poll_events;
> +	struct lttng_poll_event cpoll_events;
> +

Remove empty line here.

> +	int hupfd[2];
> +	int infd[2];
> +	pid_t cpid;
> +	char rbuf = 0, tbuf = MAGIC_VALUE;
> +	int wstatus;
> +
> +	lttng_poll_init(&poll_events);
> +	lttng_poll_init(&cpoll_events);
> +
> +	ok(pipe(hupfd) != -1);
> +	ok(pipe(infd) != -1);
> +
> +	cpid = fork();
> +	if (cpid == 0) {
> +		childok(lttng_poll_create(&cpoll_events, 1, 0) == 0, "Create valid poll set succeeds");
> +		childok(lttng_poll_mod(NULL, infd[0], LPOLLIN) == -1, "lttng_poll_mod with invalid input returns an error");
> +		childok(lttng_poll_mod(&cpoll_events, infd[0], LPOLLIN) == -1, "lttng_poll_mod with invalid input returns an error");
> +		childok(lttng_poll_add(&cpoll_events, infd[0], LPOLLHUP) == 0, "Add valid FD succeeds");
> +		childok(lttng_poll_mod(&cpoll_events, -1, LPOLLIN) == -1, "lttng_poll_mod with invalid input returns an error");
> +		childok(lttng_poll_mod(&cpoll_events, hupfd[0], LPOLLIN) == 0, "lttng_poll_mod on unincluded FD goes on");
> +		childok(lttng_poll_mod(&cpoll_events, infd[0], LPOLLIN) == 0, "Modify event type succeeds");
> +		childok(close(infd[1]) == 0, "Close valid FD succeeds");
> +		childok(lttng_poll_wait(&cpoll_events, -1) == 1, "Wait on close times out");
> +		childok(lttng_read(infd[0], &rbuf, 1) == 1, "Data is present in the pipe");
> +		childok(rbuf == MAGIC_VALUE, "Received data is consistent with transmitted data");
> +		childok(lttng_poll_del(&cpoll_events, infd[0]) == 0, "Removing valid FD succeeds");
> +		childok(close(infd[0]) == 0, "Close valid FD succeeds");
> +		childok(close(hupfd[0]) == 0, "Close valid FD succeeds");
> +		childok(close(hupfd[1]) == 0, "Close valid FD succeeds");
> +		lttng_poll_clean(&cpoll_events);
> +		_exit(EXIT_SUCCESS);
> +	} else {
> +		ok(close(hupfd[1]) == 0, "Close valid FD succeeds");
> +		ok(close(infd[0]) == 0, "Close valid FD succeeds");
> +
> +		ok(lttng_poll_wait(NULL, -1) == -1, "lttng_poll_wait call with invalid input returns error");
> +
> +		ok(lttng_poll_create(&poll_events, 1, 0) == 0, "Create valid poll set succeeds");
> +		ok(lttng_poll_wait(&poll_events, -1) == -1, "lttng_poll_wait call with invalid input returns error");
> +		ok(lttng_poll_add(&poll_events, hupfd[0], LPOLLHUP) == 0, "Add valid FD succeeds");
> +		ok(lttng_write(infd[1], &tbuf, 1) == 1, "Write to pipe succeeds");
> +		ok(lttng_poll_wait(&poll_events, -1) == 1, "Wakes up on one event");
> +		ok(lttng_poll_del(&poll_events, hupfd[0]) == 0, "Removing valid FD succeeds");
> +		ok(close(hupfd[0]) == 0, "Close valid FD succeeds");
> +		ok(close(infd[1]) == 0, "Close valid FD succeeds");
> +		lttng_poll_clean(&poll_events);
> +
> +		ok(waitpid(cpid, &wstatus, 0) == cpid, "waitpid returns child's pid");
> +		ok(WIFEXITED(wstatus) == 1, "Child process exited");
> +		ok(WEXITSTATUS(wstatus) == (EXIT_SUCCESS & 0xff), "EXIT_SUCCESS is %i while exit status is %i\n", EXIT_SUCCESS, WEXITSTATUS(wstatus));
> +	}
> +
> +}
> +
> +void test_func_def(void)
> +{
> +#ifdef LTTNG_POLL_GETFD
> +#define PASS_GETFD 1
> +#else
> +#define PASS_GETFD 0
> +#endif
> +
> +#ifdef LTTNG_POLL_GETEV
> +#define PASS_GETEV 1
> +#else
> +#define PASS_GETEV 0
> +#endif
> +
> +#ifdef LTTNG_POLL_GETSZ
> +#define PASS_GETSZ 1
> +#else
> +#define PASS_GETSZ 0
> +#endif
> +
> +#ifdef LTTNG_POLL_GET_PREV_FD
> +#define PASS_GET_PREV_FD 1
> +#else
> +#define PASS_GET_PREV_FD 0
> +#endif
> +
> +	ok(lttng_poll_reset == lttng_poll_reset, "lttng_poll_reset is defined");
> +	ok(lttng_poll_init == lttng_poll_init , "lttng_poll_reset is defined");

Replace 'reset' by 'init' in the test output.

> +	ok(PASS_GETFD, "GETFD is defined");
> +	ok(PASS_GETEV, "GETEV is defined");
> +	ok(PASS_GETSZ, "GETSZ is defined");
> +	ok(PASS_GET_PREV_FD, "GET_PREV_FD is defined");
> +

Remove empty line here.

Thanks!
Jérémie

> +}
> +
> +int main(void)
> +{
> +	plan_tests(NUM_TESTS);
> +#ifdef HAVE_EPOLL
> +	test_epoll_compat();
> +#endif
> +	test_func_def();
> +	test_alloc();
> +	test_add_del();
> +	test_mod_wait();
> +	return exit_status();
> +}
> -- 
> 2.11.0
> 

Re: [PATCH lttng-tools v4 4/8] Adapt poll layer behaviour to match the epoll layer

[Jérémie Galarneau]

On Mon, Apr 01, 2019 at 01:59:21PM -0400, Yannick Lamarre wrote:
> Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
> ---
>  src/common/compat/compat-poll.c | 30 ++++++++++++++++++++----------
>  1 file changed, 20 insertions(+), 10 deletions(-)
> 
> diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c
> index b45b39dc..be655728 100644
> --- a/src/common/compat/compat-poll.c
> +++ b/src/common/compat/compat-poll.c
> @@ -1,5 +1,6 @@
>  /*
>   * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
> + * Copyright (C)  2019 - Yannick Lamarre <ylamarre@efficios.com>
>   *
>   * This program is free software; you can redistribute it and/or modify
>   * it under the terms of the GNU General Public License, version 2 only,
> @@ -204,10 +205,10 @@ int compat_poll_mod(struct lttng_poll_event *events, int fd,
>  		uint32_t req_events)
>  {
>  	int i;
> -	bool fd_found = false;
>  	struct compat_poll_event_array *current;
>  
> -	if (events == NULL || events->current.events == NULL || fd < 0) {
> +	if (events == NULL || events->current.nb_fd == 0 ||
> +			events->current.events == NULL || fd < 0) {
>  		ERR("Bad compat poll mod arguments");
>  		goto error;
>  	}
> @@ -216,16 +217,16 @@ int compat_poll_mod(struct lttng_poll_event *events, int fd,
>  
>  	for (i = 0; i < current->nb_fd; i++) {
>  		if (current->events[i].fd == fd) {
> -			fd_found = true;
>  			current->events[i].events = req_events;
>  			events->need_update = 1;
>  			break;
>  		}
>  	}
>  
> -	if (!fd_found) {
> -		goto error;
> -	}
> +	/*

Remove space after '/*'

Thanks!
Jérémie

> +	 * The epoll flavor doesn't flag modifying a non-included FD as an
> +	 * error.
> +	 */
>  
>  	return 0;
>  
> @@ -238,11 +239,12 @@ error:
>   */
>  int compat_poll_del(struct lttng_poll_event *events, int fd)
>  {
> -	int new_size, i, count = 0, ret;
> +	int i, count = 0, ret;
> +	uint32_t new_size;
>  	struct compat_poll_event_array *current;
>  
> -	if (events == NULL || events->current.events == NULL || fd < 0) {
> -		ERR("Wrong arguments for poll del");
> +	if (events == NULL || events->current.nb_fd == 0 ||
> +			events->current.events == NULL || fd < 0) {
>  		goto error;
>  	}
>  
> @@ -257,13 +259,20 @@ int compat_poll_del(struct lttng_poll_event *events, int fd)
>  			count++;
>  		}
>  	}
> +
> +	/* The fd was not in our set, return no error as with epoll. */
> +	if (current->nb_fd == count) {
> +		goto end;
> +	}
> +
>  	/* No fd duplicate should be ever added into array. */
>  	assert(current->nb_fd - 1 == count);
>  	current->nb_fd = count;
>  
>  	/* Resize array if needed. */
>  	new_size = 1U << utils_get_count_order_u32(current->nb_fd);
> -	if (new_size != current->alloc_size && new_size >= current->init_size) {
> +	if (new_size != current->alloc_size && new_size >= current->init_size
> +			&& current->nb_fd != 0) {
>  		ret = resize_poll_event(current, new_size);
>  		if (ret < 0) {
>  			goto error;
> @@ -272,6 +281,7 @@ int compat_poll_del(struct lttng_poll_event *events, int fd)
>  
>  	events->need_update = 1;
>  
> +end:
>  	return 0;
>  
>  error:
> -- 
> 2.11.0
> 

Re: [PATCH lttng-tools v4 6/8] Change lttng_poll_wait behaviour of compat-poll to match compat-epoll

[Jérémie Galarneau]

On Mon, Apr 01, 2019 at 01:59:23PM -0400, Yannick Lamarre wrote:
> This removes the need to verify for idle file descriptors and mitigates
> risks of bug due to behaviour mismatch.
> 
> Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
> ---
> 
> The assert in the for loop is removed.
> 
>  src/common/compat/compat-poll.c | 37 +++++++++++++++++++++++++++++++++----
>  1 file changed, 33 insertions(+), 4 deletions(-)
> 
> diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c
> index be655728..5b752a28 100644
> --- a/src/common/compat/compat-poll.c
> +++ b/src/common/compat/compat-poll.c
> @@ -293,7 +293,8 @@ error:
>   */
>  int compat_poll_wait(struct lttng_poll_event *events, int timeout)
>  {
> -	int ret;
> +	int ret, active_fd_count;
> +	int idle_pfd_index = 0;
>  
>  	if (events == NULL || events->current.events == NULL) {
>  		ERR("poll wait arguments error");
> @@ -325,11 +326,39 @@ int compat_poll_wait(struct lttng_poll_event *events, int timeout)
>  		goto error;
>  	}
>  
> +	active_fd_count = ret;
> +
>  	/*
> -	 * poll() should always iterate on all FDs since we handle the pollset in
> -	 * user space and after poll returns, we have to try every fd for a match.
> +	 * Swap all active pollfd structs to the beginning of the
> +	 * array to emulate compat-epoll behaviour. This algorithm takes
> +	 * advantage of poll's returned value and the burst nature of active
> +	 * events on the file descriptors. The while loop guarantees that
> +	 * idle_pfd will always point to an idle fd.
>  	 */
> -	return events->wait.nb_fd;
> +	if (active_fd_count == events->wait.nb_fd) {
> +		goto end;
> +	}
> +	while (idle_pfd_index < active_fd_count &&
> +			events->wait.events[idle_pfd_index].revents != 0) {
> +		idle_pfd_index++;
> +	}
> +
> +	for (int i = idle_pfd_index + 1; idle_pfd_index < active_fd_count;
> +			i++) {

Declare 'i' at the beginning of the function.

Thanks!
Jérémie

> +		struct pollfd swap_pfd;
> +		struct pollfd *idle_pfd = &events->wait.events[idle_pfd_index];
> +		struct pollfd *current_pfd = &events->wait.events[i];
> +
> +		if (ipfd->revents != 0) {
> +			swap_pfd = *current_pfd;
> +			*current_pfd = *idle_pfd;
> +			*idle_pfd = swap_pfd;
> +			idle_pfd_index++;
> +		}
> +	}
> +
> +end:
> +	return ret;
>  
>  error:
>  	return -1;
> -- 
> 2.11.0
>