X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=ltt-context.c;h=60ea525bb3e6c17cfae94ed7736ac9651d73bdc1;hb=edb5c2da83545004c5f556accb79d010a6b1e3a9;hp=89e54bf80dd7980647018e63075b8692629ed601;hpb=9e7e489272e646b39c51e3074de800e928bb5cec;p=lttng-modules.git

diff --git a/ltt-context.c b/ltt-context.c
index 89e54bf8..60ea525b 100644
--- a/ltt-context.c
+++ b/ltt-context.c
@@ -4,6 +4,8 @@
  * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
  * LTTng trace/channel/event context management.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
  */
 
 #include <linux/module.h>
@@ -14,6 +16,24 @@
 #include "ltt-events.h"
 #include "ltt-tracer.h"
 
+int lttng_find_context(struct lttng_ctx *ctx, const char *name)
+{
+	unsigned int i;
+
+	for (i = 0; i < ctx->nr_fields; i++) {
+		/* Skip allocated (but non-initialized) contexts */
+		if (!ctx->fields[i].event_field.name)
+			continue;
+		if (!strcmp(ctx->fields[i].event_field.name, name))
+			return 1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(lttng_find_context);
+
+/*
+ * Note: as we append context information, the pointer location may change.
+ */
 struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
 {
 	struct lttng_ctx_field *field;
@@ -28,12 +48,12 @@ struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
 	if (ctx->nr_fields + 1 > ctx->allocated_fields) {
 		struct lttng_ctx_field *new_fields;
 
-		ctx->allocated_fields = min_t(size_t, 1, 2 * ctx->allocated_fields);
+		ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields);
 		new_fields = kzalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field), GFP_KERNEL);
 		if (!new_fields)
 			return NULL;
 		if (ctx->fields)
-			memcpy(new_fields, ctx->fields, ctx->nr_fields);
+			memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields);
 		kfree(ctx->fields);
 		ctx->fields = new_fields;
 	}
@@ -43,10 +63,27 @@ struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
 }
 EXPORT_SYMBOL_GPL(lttng_append_context);
 
+/*
+ * Remove last context field.
+ */
+void lttng_remove_context_field(struct lttng_ctx **ctx_p,
+				struct lttng_ctx_field *field)
+{
+	struct lttng_ctx *ctx;
+
+	ctx = *ctx_p;
+	ctx->nr_fields--;
+	WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field);
+	memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field));
+}
+EXPORT_SYMBOL_GPL(lttng_remove_context_field);
+
 void lttng_destroy_context(struct lttng_ctx *ctx)
 {
 	int i;
 
+	if (!ctx)
+		return;
 	for (i = 0; i < ctx->nr_fields; i++) {
 		if (ctx->fields[i].destroy)
 			ctx->fields[i].destroy(&ctx->fields[i]);