From: David Goulet <dgoulet@efficios.com>
Date: Fri, 6 Apr 2012 19:24:53 +0000 (-0400)
Subject: Don't report back error on syscalls fail for -a -k
X-Git-Tag: v2.1.0-rc1~159
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=bd29c13d4c9296705a4444404a69c0557e5b8cb9

Don't report back error on syscalls fail for -a -k

lttng enable-event -a -k will not report an error anymmore if enabling
syscall events has failed. Please refer to the commitdiff for a detailed
comment on why this is done like so.

Signed-off-by: David Goulet <dgoulet@efficios.com>
---

diff --git a/src/bin/lttng-sessiond/event.c b/src/bin/lttng-sessiond/event.c
index ac4b0b4a3..6e9cc006f 100644
--- a/src/bin/lttng-sessiond/event.c
+++ b/src/bin/lttng-sessiond/event.c
@@ -134,10 +134,16 @@ int event_kernel_enable_tracepoint(struct ltt_kernel_session *ksession,
 	if (kevent == NULL) {
 		ret = kernel_create_event(event, kchan);
 		if (ret < 0) {
-			if (ret == -EEXIST) {
+			switch (-ret) {
+			case EEXIST:
 				ret = LTTCOMM_KERN_EVENT_EXIST;
-			} else {
+				break;
+			case ENOSYS:
+				ret = LTTCOMM_KERN_EVENT_ENOSYS;
+				break;
+			default:
 				ret = LTTCOMM_KERN_ENABLE_FAIL;
+				break;
 			}
 			goto end;
 		}
@@ -239,15 +245,27 @@ end:
 int event_kernel_enable_all(struct ltt_kernel_session *ksession,
 		struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
 {
-	int ret;
+	int tp_ret, syscall_ret;
 
-	ret = event_kernel_enable_all_tracepoints(ksession, kchan, kernel_tracer_fd);
-	if (ret != LTTCOMM_OK) {
+	tp_ret = event_kernel_enable_all_tracepoints(ksession, kchan, kernel_tracer_fd);
+	if (tp_ret != LTTCOMM_OK) {
 		goto end;
 	}
-	ret = event_kernel_enable_all_syscalls(ksession, kchan, kernel_tracer_fd);
+
+	/*
+	 * Reaching this code path means that all tracepoints were enabled without
+	 * errors so we ignore the error value of syscalls.
+	 *
+	 * At the moment, failing to enable syscalls on "lttng enable-event -a -k"
+	 * is not considered an error that need to be returned to the client since
+	 * tracepoints did not fail. Future work will allow us to send back
+	 * multiple errors to the client in one API call.
+	 */
+	syscall_ret = event_kernel_enable_all_syscalls(ksession, kchan,
+			kernel_tracer_fd);
+
 end:
-	return ret;
+	return tp_ret;
 }
 
 /*
diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 596af588c..39006ab2f 100644
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -196,7 +196,13 @@ int kernel_create_event(struct lttng_event *ev,
 
 	ret = kernctl_create_event(channel->fd, event->event);
 	if (ret < 0) {
-		if (errno != EEXIST) {
+		switch (errno) {
+		case EEXIST:
+			break;
+		case ENOSYS:
+			WARN("Event type not implemented");
+			break;
+		default:
 			PERROR("create event ioctl");
 		}
 		ret = -errno;
diff --git a/src/common/sessiond-comm/sessiond-comm.c b/src/common/sessiond-comm/sessiond-comm.c
index f396c42f3..11319f333 100644
--- a/src/common/sessiond-comm/sessiond-comm.c
+++ b/src/common/sessiond-comm/sessiond-comm.c
@@ -105,6 +105,7 @@ static const char *lttcomm_readable_code[] = {
 	[ LTTCOMM_ERR_INDEX(LTTCOMM_NEED_ROOT_SESSIOND) ] = "Tracing the kernel requires a root lttng-sessiond daemon and \"tracing\" group user membership",
 	[ LTTCOMM_ERR_INDEX(LTTCOMM_TRACE_ALREADY_STARTED) ] = "Tracing already started",
 	[ LTTCOMM_ERR_INDEX(LTTCOMM_TRACE_ALREADY_STOPPED) ] = "Tracing already stopped",
+	[ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_ENOSYS) ] = "Kernel event type not supported",
 
 	[ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
 	[ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
diff --git a/src/common/sessiond-comm/sessiond-comm.h b/src/common/sessiond-comm/sessiond-comm.h
index dbb744c0c..6cc98d542 100644
--- a/src/common/sessiond-comm/sessiond-comm.h
+++ b/src/common/sessiond-comm/sessiond-comm.h
@@ -140,6 +140,7 @@ enum lttcomm_return_code {
 	LTTCOMM_NEED_ROOT_SESSIOND,		/* root sessiond is needed */
 	LTTCOMM_TRACE_ALREADY_STARTED,  /* Tracing already started */
 	LTTCOMM_TRACE_ALREADY_STOPPED,  /* Tracing already stopped */
+	LTTCOMM_KERN_EVENT_ENOSYS,      /* Kernel event type not supported */
 
 	CONSUMERD_COMMAND_SOCK_READY,		/* when consumerd command socket ready */
 	CONSUMERD_SUCCESS_RECV_FD,		/* success on receiving fds */