Update TODO

[lttng-modules.git] / ltt-context.c

diff --git a/ltt-context.c b/ltt-context.c
index 89e54bf80dd7980647018e63075b8692629ed601..60ea525bb3e6c17cfae94ed7736ac9651d73bdc1 100644 (file)
--- 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]);