Fix: event notification capture error handling

[lttng-modules.git] / src / lttng-event-notifier-notification.c

diff --git a/src/lttng-event-notifier-notification.c b/src/lttng-event-notifier-notification.c
index ae35b1f45697e78d774f067d2fe665dd23e8bc2d..b8f01395c57bf4e7fd3954f555aa26a286acbf7a 100644 (file)
--- a/src/lttng-event-notifier-notification.c
+++ b/src/lttng-event-notifier-notification.c
@@ -46,25 +46,21 @@ int capture_enum(struct lttng_msgpack_writer *writer,
         */
        ret = lttng_msgpack_begin_map(writer, 2);
        if (ret) {
-               WARN_ON_ONCE(1);
                goto end;
        }
 
        ret = lttng_msgpack_write_str(writer, "type");
        if (ret) {
-               WARN_ON_ONCE(1);
                goto end;
        }
 
        ret = lttng_msgpack_write_str(writer, "enum");
        if (ret) {
-               WARN_ON_ONCE(1);
                goto end;
        }
 
        ret = lttng_msgpack_write_str(writer, "value");
        if (ret) {
-               WARN_ON_ONCE(1);
                goto end;
        }
 
@@ -72,25 +68,20 @@ int capture_enum(struct lttng_msgpack_writer *writer,
        case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
                ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
                if (ret) {
-                       WARN_ON_ONCE(1);
                        goto end;
                }
                break;
        case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
                ret = lttng_msgpack_write_signed_integer(writer, output->u.u);
                if (ret) {
-                       WARN_ON_ONCE(1);
                        goto end;
                }
                break;
        default:
-               WARN_ON(1);
+               WARN_ON_ONCE(1);
        }
 
        ret = lttng_msgpack_end_map(writer);
-       if (ret)
-               WARN_ON_ONCE(1);
-
 end:
        return ret;
 }
@@ -164,7 +155,7 @@ int64_t capture_sequence_element_signed(uint8_t *ptr,
                break;
        }
        default:
-               WARN_ON(1);
+               WARN_ON_ONCE(1);
        }
 
        return value;
@@ -239,7 +230,7 @@ uint64_t capture_sequence_element_unsigned(uint8_t *ptr,
                break;
        }
        default:
-               WARN_ON(1);
+               WARN_ON_ONCE(1);
        }
 
        return value;
@@ -256,7 +247,6 @@ int capture_sequence(struct lttng_msgpack_writer *writer,
 
        ret = lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem);
        if (ret) {
-               WARN_ON_ONCE(1);
                goto end;
        }
 
@@ -272,7 +262,9 @@ int capture_sequence(struct lttng_msgpack_writer *writer,
                break;
        default:
                /* Capture of array of non-integer are not supported. */
-               WARN_ON(1);
+               WARN_ON_ONCE(1);
+               ret = -1;
+               goto end;
        }
        signedness = integer_type->signedness;
        for (i = 0; i < output->u.sequence.nr_elem; i++) {
@@ -280,14 +272,12 @@ int capture_sequence(struct lttng_msgpack_writer *writer,
                        ret = lttng_msgpack_write_signed_integer(writer,
                                capture_sequence_element_signed(ptr, integer_type));
                        if (ret) {
-                               WARN_ON_ONCE(1);
                                goto end;
                        }
                } else {
                        ret = lttng_msgpack_write_unsigned_integer(writer,
                                capture_sequence_element_unsigned(ptr, integer_type));
                        if (ret) {
-                               WARN_ON_ONCE(1);
                                goto end;
                        }
                }
@@ -299,15 +289,13 @@ int capture_sequence(struct lttng_msgpack_writer *writer,
                 * take into account that the next element might be further
                 * away.
                 */
-               WARN_ON(integer_type->alignment > integer_type->size);
+               WARN_ON_ONCE(integer_type->alignment > integer_type->size);
 
                /* Size is in number of bits. */
                ptr += (integer_type->size / CHAR_BIT) ;
        }
 
        ret = lttng_msgpack_end_array(writer);
-       if (ret)
-               WARN_ON_ONCE(1);
 end:
        return ret;
 }
@@ -323,17 +311,9 @@ int notification_append_capture(
        switch (output->type) {
        case LTTNG_INTERPRETER_TYPE_S64:
                ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
-               if (ret) {
-                       WARN_ON_ONCE(1);
-                       goto end;
-               }
                break;
        case LTTNG_INTERPRETER_TYPE_U64:
                ret = lttng_msgpack_write_unsigned_integer(writer, output->u.u);
-               if (ret) {
-                       WARN_ON_ONCE(1);
-                       goto end;
-               }
                break;
        case LTTNG_INTERPRETER_TYPE_STRING:
                if (output->u.str.user) {
@@ -341,31 +321,18 @@ int notification_append_capture(
                } else {
                        ret = lttng_msgpack_write_str(writer, output->u.str.str);
                }
-               if (ret) {
-                       WARN_ON_ONCE(1);
-                       goto end;
-               }
                break;
        case LTTNG_INTERPRETER_TYPE_SEQUENCE:
                ret = capture_sequence(writer, output);
-               if (ret) {
-                       WARN_ON_ONCE(1);
-                       goto end;
-               }
                break;
        case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
        case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
                ret = capture_enum(writer, output);
-               if (ret) {
-                       WARN_ON_ONCE(1);
-                       goto end;
-               }
                break;
        default:
                ret = -1;
-               WARN_ON(1);
+               WARN_ON_ONCE(1);
        }
-end:
        return ret;
 }
 
@@ -373,11 +340,7 @@ static
 int notification_append_empty_capture(
                struct lttng_event_notifier_notification *notif)
 {
-       int ret = lttng_msgpack_write_nil(&notif->writer);
-       if (ret)
-               WARN_ON_ONCE(1);
-
-       return ret;
+       return lttng_msgpack_write_nil(&notif->writer);
 }
 
 static
@@ -395,7 +358,6 @@ int notification_init(struct lttng_event_notifier_notification *notif,
 
                ret = lttng_msgpack_begin_array(writer, event_notifier->priv->num_captures);
                if (ret) {
-                       WARN_ON_ONCE(1);
                        goto end;
                }
 
@@ -486,14 +448,12 @@ void lttng_event_notifier_notification_send(struct lttng_kernel_event_notifier *
                struct lttng_kernel_notification_ctx *notif_ctx)
 {
        struct lttng_event_notifier_notification notif = { 0 };
-       int ret;
 
        if (unlikely(!READ_ONCE(event_notifier->parent.enabled)))
                return;
 
-       ret = notification_init(&notif, event_notifier);
-       if (ret) {
-               WARN_ON_ONCE(1);
+       if (notification_init(&notif, event_notifier)) {
+               record_error(event_notifier);
                goto end;
        }
 
@@ -509,15 +469,23 @@ void lttng_event_notifier_notification_send(struct lttng_kernel_event_notifier *
                list_for_each_entry_rcu(capture_bc_runtime,
                                &event_notifier->priv->capture_bytecode_runtime_head, node) {
                        struct lttng_interpreter_output output;
+                       uint8_t *save_pos;
+                       int ret;
 
+                       lttng_msgpack_save_writer_pos(&notif.writer, &save_pos);
                        if (capture_bc_runtime->interpreter_func(capture_bc_runtime,
                                        stack_data, probe_ctx, &output) == LTTNG_KERNEL_BYTECODE_INTERPRETER_OK)
                                ret = notification_append_capture(&notif, &output);
                        else
                                ret = notification_append_empty_capture(&notif);
-
-                       if (ret)
-                               printk(KERN_WARNING "Error appending capture to notification");
+                       if (ret) {
+                               /*
+                                * On append capture error, skip the field
+                                * capture by restoring the msgpack writer
+                                * position.
+                                */
+                               lttng_msgpack_restore_writer_pos(&notif.writer, save_pos);
+                       }
                }
        }