| /* |
| * 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); |
| } |