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/*
* ltt-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 "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;
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);
}
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