| 1 | /* |
| 2 | * ltt-context.c |
| 3 | * |
| 4 | * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | * |
| 6 | * LTTng trace/channel/event context management. |
| 7 | * |
| 8 | * Dual LGPL v2.1/GPL v2 license. |
| 9 | */ |
| 10 | |
| 11 | #include <ust/lttng-events.h> |
| 12 | #include <ust/core.h> |
| 13 | #include <string.h> |
| 14 | #include <ust/usterr-signal-safe.h> |
| 15 | |
| 16 | /* |
| 17 | * Note: as we append context information, the pointer location may change. |
| 18 | */ |
| 19 | struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p) |
| 20 | { |
| 21 | struct lttng_ctx_field *field; |
| 22 | struct lttng_ctx *ctx; |
| 23 | |
| 24 | if (!*ctx_p) { |
| 25 | *ctx_p = zmalloc(sizeof(struct lttng_ctx)); |
| 26 | if (!*ctx_p) |
| 27 | return NULL; |
| 28 | } |
| 29 | ctx = *ctx_p; |
| 30 | if (ctx->nr_fields + 1 > ctx->allocated_fields) { |
| 31 | struct lttng_ctx_field *new_fields; |
| 32 | |
| 33 | ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields); |
| 34 | new_fields = zmalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field)); |
| 35 | if (!new_fields) |
| 36 | return NULL; |
| 37 | if (ctx->fields) |
| 38 | memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields); |
| 39 | free(ctx->fields); |
| 40 | ctx->fields = new_fields; |
| 41 | } |
| 42 | field = &ctx->fields[ctx->nr_fields]; |
| 43 | ctx->nr_fields++; |
| 44 | return field; |
| 45 | } |
| 46 | |
| 47 | /* |
| 48 | * Remove last context field. |
| 49 | */ |
| 50 | void lttng_remove_context_field(struct lttng_ctx **ctx_p, |
| 51 | struct lttng_ctx_field *field) |
| 52 | { |
| 53 | struct lttng_ctx *ctx; |
| 54 | |
| 55 | ctx = *ctx_p; |
| 56 | ctx->nr_fields--; |
| 57 | WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field); |
| 58 | memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field)); |
| 59 | } |
| 60 | |
| 61 | void lttng_destroy_context(struct lttng_ctx *ctx) |
| 62 | { |
| 63 | int i; |
| 64 | |
| 65 | if (!ctx) |
| 66 | return; |
| 67 | for (i = 0; i < ctx->nr_fields; i++) { |
| 68 | if (ctx->fields[i].destroy) |
| 69 | ctx->fields[i].destroy(&ctx->fields[i]); |
| 70 | } |
| 71 | free(ctx->fields); |
| 72 | free(ctx); |
| 73 | } |