Mass rename: ltt_*/ltt-* to LTTNG_*/LTTNG-*

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

diff --git a/lttng-context.c b/lttng-context.c
new file mode 100644 (file)
index 0000000..a28a9d2
--- /dev/null
+++ b/lttng-context.c
@@ -0,0 +1,93 @@
+/*
+ * lttng-context.c
+ *
+ * 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>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include "wrapper/vmalloc.h"   /* for wrapper_vmalloc_sync_all() */
+#include "lttng-events.h"
+#include "lttng-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;
+       struct lttng_ctx *ctx;
+
+       if (!*ctx_p) {
+               *ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL);
+               if (!*ctx_p)
+                       return NULL;
+       }
+       ctx = *ctx_p;
+       if (ctx->nr_fields + 1 > ctx->allocated_fields) {
+               struct lttng_ctx_field *new_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, sizeof(*ctx->fields) * ctx->nr_fields);
+               kfree(ctx->fields);
+               ctx->fields = new_fields;
+       }
+       field = &ctx->fields[ctx->nr_fields];
+       ctx->nr_fields++;
+       return field;
+}
+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]);
+       }
+       kfree(ctx->fields);
+       kfree(ctx);
+}