sequence and variant types: use previous field for length/tag if NULL

[lttng-modules.git] / src / lttng-events.c

diff --git a/src/lttng-events.c b/src/lttng-events.c
index d881bddceb4c94fc0033f42b23b8c9a89b012c40..51c5cb39a58bcecfeb23c4cc267a36b3356b4408 100644 (file)
--- a/src/lttng-events.c
+++ b/src/lttng-events.c
@@ -89,7 +89,7 @@ int _lttng_type_statedump(struct lttng_session *session,
 static
 int _lttng_field_statedump(struct lttng_session *session,
                const struct lttng_kernel_event_field *field,
-               size_t nesting);
+               size_t nesting, const char **prev_field_name_p);
 
 void synchronize_trace(void)
 {
@@ -3052,6 +3052,7 @@ int _lttng_struct_type_statedump(struct lttng_session *session,
                const struct lttng_kernel_type_struct *type,
                size_t nesting)
 {
+       const char *prev_field_name = NULL;
        int ret;
        uint32_t i, nr_fields;
        unsigned int alignment;
@@ -3068,7 +3069,7 @@ int _lttng_struct_type_statedump(struct lttng_session *session,
                const struct lttng_kernel_event_field *iter_field;
 
                iter_field = type->fields[i];
-               ret = _lttng_field_statedump(session, iter_field, nesting + 1);
+               ret = _lttng_field_statedump(session, iter_field, nesting + 1, &prev_field_name);
                if (ret)
                        return ret;
        }
@@ -3110,11 +3111,18 @@ int _lttng_struct_field_statedump(struct lttng_session *session,
 static
 int _lttng_variant_type_statedump(struct lttng_session *session,
                const struct lttng_kernel_type_variant *type,
-               size_t nesting)
+               size_t nesting,
+               const char *prev_field_name)
 {
+       const char *tag_name;
        int ret;
        uint32_t i, nr_choices;
 
+       tag_name = type->tag_name;
+       if (!tag_name)
+               tag_name = prev_field_name;
+       if (!tag_name)
+               return -EINVAL;
        /*
         * CTF 1.8 does not allow expressing nonzero variant alignment in a nestable way.
         */
@@ -3125,7 +3133,7 @@ int _lttng_variant_type_statedump(struct lttng_session *session,
                return ret;
        ret = lttng_metadata_printf(session,
                "variant <_%s> {\n",
-               type->tag_name);
+               tag_name);
        if (ret)
                return ret;
        nr_choices = type->nr_choices;
@@ -3133,7 +3141,7 @@ int _lttng_variant_type_statedump(struct lttng_session *session,
                const struct lttng_kernel_event_field *iter_field;
 
                iter_field = type->choices[i];
-               ret = _lttng_field_statedump(session, iter_field, nesting + 1);
+               ret = _lttng_field_statedump(session, iter_field, nesting + 1, NULL);
                if (ret)
                        return ret;
        }
@@ -3151,12 +3159,14 @@ int _lttng_variant_type_statedump(struct lttng_session *session,
 static
 int _lttng_variant_field_statedump(struct lttng_session *session,
                const struct lttng_kernel_event_field *field,
-               size_t nesting)
+               size_t nesting,
+               const char *prev_field_name)
 {
        int ret;
 
        ret = _lttng_variant_type_statedump(session,
-                       lttng_kernel_get_type_variant(field->type), nesting);
+                       lttng_kernel_get_type_variant(field->type), nesting,
+                       prev_field_name);
        if (ret)
                return ret;
        return lttng_field_name_statedump(session, field, nesting);
@@ -3219,7 +3229,8 @@ int _lttng_array_field_statedump(struct lttng_session *session,
 static
 int _lttng_sequence_field_statedump(struct lttng_session *session,
                const struct lttng_kernel_event_field *field,
-               size_t nesting)
+               size_t nesting,
+               const char *prev_field_name)
 {
        int ret;
        const char *length_name;
@@ -3230,6 +3241,10 @@ int _lttng_sequence_field_statedump(struct lttng_session *session,
        WARN_ON_ONCE(!sequence_type);
 
        length_name = sequence_type->length_name;
+       if (!length_name)
+               length_name = prev_field_name;
+       if (!length_name)
+               return -EINVAL;
 
        if (sequence_type->alignment) {
                ret = print_tabs(session, nesting);
@@ -3264,7 +3279,7 @@ int _lttng_sequence_field_statedump(struct lttng_session *session,
        ret = lttng_metadata_printf(session,
                " _%s[ _%s ];\n",
                field->name,
-               sequence_type->length_name);
+               length_name);
        return ret;
 }
 
@@ -3487,7 +3502,7 @@ int _lttng_type_statedump(struct lttng_session *session,
        case lttng_kernel_type_variant:
                ret = _lttng_variant_type_statedump(session,
                                lttng_kernel_get_type_variant(type),
-                               nesting);
+                               nesting, NULL);
                break;
 
        /* Nested arrays and sequences are not supported yet. */
@@ -3506,10 +3521,14 @@ int _lttng_type_statedump(struct lttng_session *session,
 static
 int _lttng_field_statedump(struct lttng_session *session,
                const struct lttng_kernel_event_field *field,
-               size_t nesting)
+               size_t nesting,
+               const char **prev_field_name_p)
 {
+       const char *prev_field_name = NULL;
        int ret = 0;
 
+       if (prev_field_name_p)
+               prev_field_name = *prev_field_name_p;
        switch (field->type->type) {
        case lttng_kernel_type_integer:
                ret = _lttng_integer_field_statedump(session, field, nesting);
@@ -3527,16 +3546,18 @@ int _lttng_field_statedump(struct lttng_session *session,
                ret = _lttng_array_field_statedump(session, field, nesting);
                break;
        case lttng_kernel_type_sequence:
-               ret = _lttng_sequence_field_statedump(session, field, nesting);
+               ret = _lttng_sequence_field_statedump(session, field, nesting, prev_field_name);
                break;
        case lttng_kernel_type_variant:
-               ret = _lttng_variant_field_statedump(session, field, nesting);
+               ret = _lttng_variant_field_statedump(session, field, nesting, prev_field_name);
                break;
 
        default:
                WARN_ON_ONCE(1);
                return -EINVAL;
        }
+       if (prev_field_name_p)
+               *prev_field_name_p = field->name;
        return ret;
 }
 
@@ -3544,6 +3565,7 @@ static
 int _lttng_context_metadata_statedump(struct lttng_session *session,
                                    struct lttng_kernel_ctx *ctx)
 {
+       const char *prev_field_name = NULL;
        int ret = 0;
        int i;
 
@@ -3552,7 +3574,7 @@ int _lttng_context_metadata_statedump(struct lttng_session *session,
        for (i = 0; i < ctx->nr_fields; i++) {
                const struct lttng_kernel_ctx_field *field = &ctx->fields[i];
 
-               ret = _lttng_field_statedump(session, field->event_field, 2);
+               ret = _lttng_field_statedump(session, field->event_field, 2, &prev_field_name);
                if (ret)
                        return ret;
        }
@@ -3563,6 +3585,7 @@ static
 int _lttng_fields_metadata_statedump(struct lttng_session *session,
                                   struct lttng_kernel_event_recorder *event_recorder)
 {
+       const char *prev_field_name = NULL;
        const struct lttng_kernel_event_desc *desc = event_recorder->priv->parent.desc;
        int ret = 0;
        int i;
@@ -3570,7 +3593,7 @@ int _lttng_fields_metadata_statedump(struct lttng_session *session,
        for (i = 0; i < desc->nr_fields; i++) {
                const struct lttng_kernel_event_field *field = desc->fields[i];
 
-               ret = _lttng_field_statedump(session, field, 2);
+               ret = _lttng_field_statedump(session, field, 2, &prev_field_name);
                if (ret)
                        return ret;
        }