perf: Convert perf header attrs into attr events

Bypasses the attr perf header code and replaces it with a
synthesized event and processing function that accomplishes the
same thing, used when reading/writing perf data to/from a pipe.

Making the attrs into events allows them to be streamed over a
pipe along with the rest of the header data (in later patches).
It also paves the way to allowing events to be added and removed
from perf sessions dynamically.

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fweisbec@gmail.com
Cc: rostedt@goodmis.org
Cc: k-keiichi@bx.jp.nec.com
Cc: acme@ghostprotocols.net
LKML-Reference: <1270184365-8281-6-git-send-email-tzanussi@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/header.c

@@ -807,3 +807,82 @@ perf_header__find_attr(u64 id, struct perf_header *header)
 
 	return NULL;
 }
+
+int event__synthesize_attr(struct perf_event_attr *attr, u16 ids, u64 *id,
+			   event__handler_t process,
+			   struct perf_session *session)
+{
+	event_t *ev;
+	size_t size;
+	int err;
+
+	size = sizeof(struct perf_event_attr);
+	size = ALIGN(size, sizeof(u64));
+	size += sizeof(struct perf_event_header);
+	size += ids * sizeof(u64);
+
+	ev = malloc(size);
+
+	ev->attr.attr = *attr;
+	memcpy(ev->attr.id, id, ids * sizeof(u64));
+
+	ev->attr.header.type = PERF_RECORD_HEADER_ATTR;
+	ev->attr.header.size = size;
+
+	err = process(ev, session);
+
+	free(ev);
+
+	return err;
+}
+
+int event__synthesize_attrs(struct perf_header *self,
+			    event__handler_t process,
+			    struct perf_session *session)
+{
+	struct perf_header_attr	*attr;
+	int i, err = 0;
+
+	for (i = 0; i < self->attrs; i++) {
+		attr = self->attr[i];
+
+		err = event__synthesize_attr(&attr->attr, attr->ids, attr->id,
+					     process, session);
+		if (err) {
+			pr_debug("failed to create perf header attribute\n");
+			return err;
+		}
+	}
+
+	return err;
+}
+
+int event__process_attr(event_t *self, struct perf_session *session)
+{
+	struct perf_header_attr *attr;
+	unsigned int i, ids, n_ids;
+
+	attr = perf_header_attr__new(&self->attr.attr);
+	if (attr == NULL)
+		return -ENOMEM;
+
+	ids = self->header.size;
+	ids -= (void *)&self->attr.id - (void *)self;
+	n_ids = ids / sizeof(u64);
+
+	for (i = 0; i < n_ids; i++) {
+		if (perf_header_attr__add_id(attr, self->attr.id[i]) < 0) {
+			perf_header_attr__delete(attr);
+			return -ENOMEM;
+		}
+	}
+
+	if (perf_header__add_attr(&session->header, attr) < 0) {
+		perf_header_attr__delete(attr);
+		return -ENOMEM;
+	}
+
+	perf_session__update_sample_type(session);
+
+	return 0;
+}