Add EEXIST support for kernel event on the tracer side

[lttng-tools.git] / ltt-sessiond / event.c

diff --git a/ltt-sessiond/event.c b/ltt-sessiond/event.c
index 66e134e4641be8690f9fffbbb10086a96d229bdc..c12e385b31015bd41207947d42a807db22d75a92 100644 (file)
--- a/ltt-sessiond/event.c
+++ b/ltt-sessiond/event.c
@@ -15,6 +15,7 @@
  * Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 
+#include <errno.h>
 #include <urcu/list.h>
 
 #include <lttng/lttng.h>
@@ -39,9 +40,9 @@ static void init_syscalls_kernel_event(struct lttng_event *event)
 }
 
 /*
- * Disable kernel event for a channel from the kernel session.
+ * Disable kernel tracepoint event for a channel from the kernel session.
  */
-int event_kernel_disable(struct ltt_kernel_session *ksession,
+int event_kernel_disable_tracepoint(struct ltt_kernel_session *ksession,
                struct ltt_kernel_channel *kchan, char *event_name)
 {
        int ret;
@@ -69,9 +70,9 @@ error:
 }
 
 /*
- * Disable all kernel event for a channel from the kernel session.
+ * Disable kernel tracepoint events for a channel from the kernel session.
  */
-int event_kernel_disable_all(struct ltt_kernel_session *ksession,
+int event_kernel_disable_all_tracepoints(struct ltt_kernel_session *ksession,
                struct ltt_kernel_channel *kchan)
 {
        int ret;
@@ -85,16 +86,39 @@ int event_kernel_disable_all(struct ltt_kernel_session *ksession,
                        continue;
                }
        }
-
        ret = LTTCOMM_OK;
+       return ret;
+}
+
+/*
+ * Disable kernel syscall events for a channel from the kernel session.
+ */
+int event_kernel_disable_all_syscalls(struct ltt_kernel_session *ksession,
+               struct ltt_kernel_channel *kchan)
+{
+       ERR("Cannot disable syscall tracing for existing session. Please destroy session instead.");
+       return LTTCOMM_OK;      /* Return OK so disable all succeeds */
+}
 
+/*
+ * Disable all kernel event for a channel from the kernel session.
+ */
+int event_kernel_disable_all(struct ltt_kernel_session *ksession,
+               struct ltt_kernel_channel *kchan)
+{
+       int ret;
+
+       ret = event_kernel_disable_all_tracepoints(ksession, kchan);
+       if (ret != LTTCOMM_OK)
+               return ret;
+       ret = event_kernel_disable_all_syscalls(ksession, kchan);
        return ret;
 }
 
 /*
- * Enable kernel event for a channel from the kernel session.
+ * Enable kernel tracepoint event for a channel from the kernel session.
  */
-int event_kernel_enable(struct ltt_kernel_session *ksession,
+int event_kernel_enable_tracepoint(struct ltt_kernel_session *ksession,
                struct ltt_kernel_channel *kchan, struct lttng_event *event)
 {
        int ret;
@@ -104,27 +128,29 @@ int event_kernel_enable(struct ltt_kernel_session *ksession,
        if (kevent == NULL) {
                ret = kernel_create_event(event, kchan);
                if (ret < 0) {
-                       ret = LTTCOMM_KERN_ENABLE_FAIL;
-                       goto error;
+                       if (ret == -EEXIST) {
+                               ret = LTTCOMM_KERN_EVENT_EXIST;
+                       } else {
+                               ret = LTTCOMM_KERN_ENABLE_FAIL;
+                       }
+                       goto end;
                }
        } else if (kevent->enabled == 0) {
                ret = kernel_enable_event(kevent);
                if (ret < 0) {
                        ret = LTTCOMM_KERN_ENABLE_FAIL;
-                       goto error;
+                       goto end;
                }
        }
-
        ret = LTTCOMM_OK;
-
-error:
+end:
        return ret;
 }
 
 /*
- * Enable all kernel event of a channel of the kernel session.
+ * Enable all kernel tracepoint events of a channel of the kernel session.
  */
-int event_kernel_enable_all(struct ltt_kernel_session *ksession,
+int event_kernel_enable_all_tracepoints(struct ltt_kernel_session *ksession,
                struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
 {
        int size, i, ret;
@@ -143,7 +169,7 @@ int event_kernel_enable_all(struct ltt_kernel_session *ksession,
        size = kernel_list_events(kernel_tracer_fd, &event_list);
        if (size < 0) {
                ret = LTTCOMM_KERN_LIST_FAIL;
-               goto error;
+               goto end;
        }
 
        for (i = 0; i < size; i++) {
@@ -158,19 +184,17 @@ int event_kernel_enable_all(struct ltt_kernel_session *ksession,
                        }
                }
        }
-
        free(event_list);
-
        ret = LTTCOMM_OK;
-
-error:
+end:
        return ret;
+
 }
 
 /*
- * Enable all kernel syscalls tracing.
+ * Enable all kernel tracepoint events of a channel of the kernel session.
  */
-int event_kernel_enable_syscalls(struct ltt_kernel_session *ksession,
+int event_kernel_enable_all_syscalls(struct ltt_kernel_session *ksession,
                struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
 {
        int ret;
@@ -182,11 +206,26 @@ int event_kernel_enable_syscalls(struct ltt_kernel_session *ksession,
 
        ret = kernel_create_event(&event, kchan);
        if (ret < 0) {
-               goto error;
+               goto end;
        }
-
        ret = LTTCOMM_OK;
+end:
+       return ret;
+}
 
-error:
+/*
+ * Enable all kernel events of a channel of the kernel session.
+ */
+int event_kernel_enable_all(struct ltt_kernel_session *ksession,
+               struct ltt_kernel_channel *kchan, int kernel_tracer_fd)
+{
+       int ret;
+
+       ret = event_kernel_enable_all_tracepoints(ksession, kchan, kernel_tracer_fd);
+       if (ret != LTTCOMM_OK) {
+               goto end;
+       }
+       ret = event_kernel_enable_all_syscalls(ksession, kchan, kernel_tracer_fd);
+end:
        return ret;
 }