X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-context.c;h=6cab7dc1721a57dbbd004cd84f5db4deed32072b;hb=b2cc986adb1aa11116ace6129dc2ec7e5c9737b1;hp=ecee23445787bce42397e96c200537b1385017ef;hpb=631dc14c99a187453b9c46aca090fcf3b7ed8ec9;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-context.c b/liblttng-ust/lttng-context.c
index ecee2344..6cab7dc1 100644
--- a/liblttng-ust/lttng-context.c
+++ b/liblttng-ust/lttng-context.c
@@ -80,6 +80,7 @@ struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
 		*ctx_p = zmalloc(sizeof(struct lttng_ctx));
 		if (!*ctx_p)
 			return NULL;
+		(*ctx_p)->largest_align = 1;
 	}
 	ctx = *ctx_p;
 	if (ctx->nr_fields + 1 > ctx->allocated_fields) {
@@ -99,6 +100,94 @@ struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
 	return field;
 }
 
+/*
+ * lttng_context_update() should be called at least once between context
+ * modification and trace start.
+ */
+void lttng_context_update(struct lttng_ctx *ctx)
+{
+	int i;
+	size_t largest_align = 8;	/* in bits */
+
+	for (i = 0; i < ctx->nr_fields; i++) {
+		struct lttng_type *type;
+		size_t field_align = 8;
+
+		type = &ctx->fields[i].event_field.type;
+		switch (type->atype) {
+		case atype_integer:
+			field_align = type->u.basic.integer.alignment;
+			break;
+		case atype_array:
+		{
+			struct lttng_basic_type *btype;
+
+			btype = &type->u.array.elem_type;
+			switch (btype->atype) {
+			case atype_integer:
+				field_align = btype->u.basic.integer.alignment;
+				break;
+			case atype_string:
+				break;
+
+			case atype_array:
+			case atype_sequence:
+			default:
+				WARN_ON_ONCE(1);
+				break;
+			}
+			break;
+		}
+		case atype_sequence:
+		{
+			struct lttng_basic_type *btype;
+
+			btype = &type->u.sequence.length_type;
+			switch (btype->atype) {
+			case atype_integer:
+				field_align = btype->u.basic.integer.alignment;
+				break;
+
+			case atype_string:
+			case atype_array:
+			case atype_sequence:
+			default:
+				WARN_ON_ONCE(1);
+				break;
+			}
+
+			btype = &type->u.sequence.elem_type;
+			switch (btype->atype) {
+			case atype_integer:
+				field_align = max_t(size_t,
+					field_align,
+					btype->u.basic.integer.alignment);
+				break;
+
+			case atype_string:
+				break;
+
+			case atype_array:
+			case atype_sequence:
+			default:
+				WARN_ON_ONCE(1);
+				break;
+			}
+			break;
+		}
+		case atype_string:
+			break;
+
+		case atype_enum:
+		default:
+			WARN_ON_ONCE(1);
+			break;
+		}
+		largest_align = max_t(size_t, largest_align, field_align);
+	}
+	ctx->largest_align = largest_align >> 3;	/* bits to bytes */
+}
+
 /*
  * Remove last context field.
  */