sequence type: use previous field for length if length_name is NULL

[lttng-ust.git] / src / common / ustcomm.c

diff --git a/src/common/ustcomm.c b/src/common/ustcomm.c
index 00cbf5a73bae82b0a30568490eb9923706036125..ada896f68f60ad1b0d077a4786c63b44f45c123d 100644 (file)
--- a/src/common/ustcomm.c
+++ b/src/common/ustcomm.c
@@ -37,7 +37,8 @@ ssize_t count_fields_recursive(size_t nr_fields,
 static
 int serialize_one_field(struct lttng_ust_session *session,
                struct lttng_ust_ctl_field *fields, size_t *iter_output,
-               const struct lttng_ust_event_field *lf);
+               const struct lttng_ust_event_field *lf,
+               const char **prev_field_name);
 static
 int serialize_fields(struct lttng_ust_session *session,
                struct lttng_ust_ctl_field *lttng_ust_ctl_fields,
@@ -973,7 +974,7 @@ int serialize_dynamic_type(struct lttng_ust_session *session,
                LTTNG_UST_ABI_SYM_NAME_LEN - strlen(tag_field_name) - 1);
        tag_field.type = tag_type;
        ret = serialize_one_field(session, fields, iter_output,
-               &tag_field);
+               &tag_field, NULL);
        if (ret)
                return ret;
 
@@ -997,7 +998,7 @@ int serialize_dynamic_type(struct lttng_ust_session *session,
        /* Serialize choice fields after variant. */
        for (i = 0; i < nr_choices; i++) {
                ret = serialize_one_field(session, fields,
-                       iter_output, choices[i]);
+                       iter_output, choices[i], NULL);
                if (ret)
                        return ret;
        }
@@ -1008,7 +1009,8 @@ static
 int serialize_one_type(struct lttng_ust_session *session,
                struct lttng_ust_ctl_field *fields, size_t *iter_output,
                const char *field_name, const struct lttng_ust_type_common *lt,
-               enum lttng_ust_string_encoding parent_encoding)
+               enum lttng_ust_string_encoding parent_encoding,
+               const char *prev_field_name)
 {
        int ret;
 
@@ -1098,7 +1100,7 @@ int serialize_one_type(struct lttng_ust_session *session,
 
                ret = serialize_one_type(session, fields, iter_output, NULL,
                                lttng_ust_get_type_array(lt)->elem_type,
-                               lttng_ust_get_type_array(lt)->encoding);
+                               lttng_ust_get_type_array(lt)->encoding, NULL);
                if (ret)
                        return -EINVAL;
                break;
@@ -1107,6 +1109,7 @@ int serialize_one_type(struct lttng_ust_session *session,
        {
                struct lttng_ust_ctl_field *uf = &fields[*iter_output];
                struct lttng_ust_ctl_type *ut = &uf->type;
+               const char *length_name = lttng_ust_get_type_sequence(lt)->length_name;
 
                if (field_name) {
                        strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
@@ -1115,16 +1118,23 @@ int serialize_one_type(struct lttng_ust_session *session,
                        uf->name[0] = '\0';
                }
                ut->atype = lttng_ust_ctl_atype_sequence_nestable;
+               /*
+                * If length_name field is NULL, use the previous field
+                * as length.
+                */
+               if (!length_name)
+                       length_name = prev_field_name;
+               if (!length_name)
+                       return -EINVAL;
                strncpy(ut->u.sequence_nestable.length_name,
-                       lttng_ust_get_type_sequence(lt)->length_name,
-                       LTTNG_UST_ABI_SYM_NAME_LEN);
+                       length_name, LTTNG_UST_ABI_SYM_NAME_LEN);
                ut->u.sequence_nestable.length_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
                ut->u.sequence_nestable.alignment = lttng_ust_get_type_sequence(lt)->alignment;
                (*iter_output)++;
 
                ret = serialize_one_type(session, fields, iter_output, NULL,
                                lttng_ust_get_type_sequence(lt)->elem_type,
-                               lttng_ust_get_type_sequence(lt)->encoding);
+                               lttng_ust_get_type_sequence(lt)->encoding, NULL);
                if (ret)
                        return -EINVAL;
                break;
@@ -1178,7 +1188,7 @@ int serialize_one_type(struct lttng_ust_session *session,
 
                ret = serialize_one_type(session, fields, iter_output, NULL,
                                lttng_ust_get_type_enum(lt)->container_type,
-                               lttng_ust_string_encoding_none);
+                               lttng_ust_string_encoding_none, NULL);
                if (ret)
                        return -EINVAL;
                if (session) {
@@ -1202,13 +1212,23 @@ int serialize_one_type(struct lttng_ust_session *session,
 static
 int serialize_one_field(struct lttng_ust_session *session,
                struct lttng_ust_ctl_field *fields, size_t *iter_output,
-               const struct lttng_ust_event_field *lf)
+               const struct lttng_ust_event_field *lf,
+               const char **prev_field_name_p)
 {
+       const char *prev_field_name = NULL;
+       int ret;
+
        /* skip 'nowrite' fields */
        if (lf->nowrite)
                return 0;
 
-       return serialize_one_type(session, fields, iter_output, lf->name, lf->type, lttng_ust_string_encoding_none);
+       if (prev_field_name_p)
+               prev_field_name = *prev_field_name_p;
+       ret = serialize_one_type(session, fields, iter_output, lf->name, lf->type,
+                       lttng_ust_string_encoding_none, prev_field_name);
+       if (prev_field_name_p)
+               *prev_field_name_p = lf->name;
+       return ret;
 }
 
 static
@@ -1217,12 +1237,14 @@ int serialize_fields(struct lttng_ust_session *session,
                size_t *iter_output, size_t nr_lttng_fields,
                const struct lttng_ust_event_field * const *lttng_fields)
 {
+       const char *prev_field_name = NULL;
        int ret;
        size_t i;
 
        for (i = 0; i < nr_lttng_fields; i++) {
                ret = serialize_one_field(session, lttng_ust_ctl_fields,
-                               iter_output, lttng_fields[i]);
+                               iter_output, lttng_fields[i],
+                               &prev_field_name);
                if (ret)
                        return ret;
        }
@@ -1307,9 +1329,10 @@ int serialize_ctx_fields(struct lttng_ust_session *session,
                struct lttng_ust_ctx_field *lttng_fields)
 {
        struct lttng_ust_ctl_field *fields;
-       int ret;
+       const char *prev_field_name = NULL;
        size_t i, iter_output = 0;
        ssize_t nr_write_fields;
+       int ret;
 
        nr_write_fields = count_ctx_fields_recursive(nr_fields,
                        lttng_fields);
@@ -1323,7 +1346,7 @@ int serialize_ctx_fields(struct lttng_ust_session *session,
 
        for (i = 0; i < nr_fields; i++) {
                ret = serialize_one_field(session, fields, &iter_output,
-                               lttng_fields[i].event_field);
+                               lttng_fields[i].event_field, &prev_field_name);
                if (ret)
                        goto error_type;
        }