doc: remove duplicate LTTNG_UST_BLOCKING_RETRY_TIMEOUT man page entry

[lttng-ust.git] / liblttng-ust / lttng-ring-buffer-client.h

diff --git a/liblttng-ust/lttng-ring-buffer-client.h b/liblttng-ust/lttng-ring-buffer-client.h
index 1ebb14e48ff05e218994dbc8710eb566b22f9fcd..6ed067105d8e7fd0f8a280e3f09caa0375186836 100644 (file)
--- a/liblttng-ust/lttng-ring-buffer-client.h
+++ b/liblttng-ust/lttng-ring-buffer-client.h
@@ -30,6 +30,11 @@
 #define LTTNG_COMPACT_EVENT_BITS       5
 #define LTTNG_COMPACT_TSC_BITS         27
 
+enum app_ctx_mode {
+       APP_CTX_DISABLED,
+       APP_CTX_ENABLED,
+};
+
 /*
  * Keep the natural field alignment for _each field_ within this structure if
  * you ever add/remove a field from this header. Packed attribute is not used
@@ -71,7 +76,8 @@ static inline uint64_t lib_ring_buffer_clock_read(struct channel *chan)
 }
 
 static inline
-size_t ctx_get_size(size_t offset, struct lttng_ctx *ctx)
+size_t ctx_get_size(size_t offset, struct lttng_ctx *ctx,
+               enum app_ctx_mode mode)
 {
        int i;
        size_t orig_offset = offset;
@@ -79,23 +85,62 @@ size_t ctx_get_size(size_t offset, struct lttng_ctx *ctx)
        if (caa_likely(!ctx))
                return 0;
        offset += lib_ring_buffer_align(offset, ctx->largest_align);
-       for (i = 0; i < ctx->nr_fields; i++)
-               offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
+       for (i = 0; i < ctx->nr_fields; i++) {
+               if (mode == APP_CTX_ENABLED) {
+                       offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
+               } else {
+                       if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
+                               /*
+                                * Before UST 2.8, we cannot use the
+                                * application context, because we
+                                * cannot trust that the handler used
+                                * for get_size is the same used for
+                                * ctx_record, which would result in
+                                * corrupted traces when tracing
+                                * concurrently with application context
+                                * register/unregister.
+                                */
+                               offset += lttng_ust_dummy_get_size(&ctx->fields[i], offset);
+                       } else {
+                               offset += ctx->fields[i].get_size(&ctx->fields[i], offset);
+                       }
+               }
+       }
        return offset - orig_offset;
 }
 
 static inline
 void ctx_record(struct lttng_ust_lib_ring_buffer_ctx *bufctx,
                struct lttng_channel *chan,
-               struct lttng_ctx *ctx)
+               struct lttng_ctx *ctx,
+               enum app_ctx_mode mode)
 {
        int i;
 
        if (caa_likely(!ctx))
                return;
        lib_ring_buffer_align_ctx(bufctx, ctx->largest_align);
-       for (i = 0; i < ctx->nr_fields; i++)
-               ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
+       for (i = 0; i < ctx->nr_fields; i++) {
+               if (mode == APP_CTX_ENABLED) {
+                       ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
+               } else {
+                       if (lttng_context_is_app(ctx->fields[i].event_field.name)) {
+                               /*
+                                * Before UST 2.8, we cannot use the
+                                * application context, because we
+                                * cannot trust that the handler used
+                                * for get_size is the same used for
+                                * ctx_record, which would result in
+                                * corrupted traces when tracing
+                                * concurrently with application context
+                                * register/unregister.
+                                */
+                               lttng_ust_dummy_record(&ctx->fields[i], bufctx, chan);
+                       } else {
+                               ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
+                       }
+               }
+       }
 }
 
 /*
@@ -118,6 +163,7 @@ size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
                                 struct lttng_ust_lib_ring_buffer_ctx *ctx)
 {
        struct lttng_channel *lttng_chan = channel_get_private(chan);
+       struct lttng_event *event = ctx->priv;
        struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
        size_t orig_offset = offset;
        size_t padding;
@@ -157,9 +203,15 @@ size_t record_header_size(const struct lttng_ust_lib_ring_buffer_config *config,
                padding = 0;
                WARN_ON_ONCE(1);
        }
-       offset += ctx_get_size(offset, lttng_ctx->chan_ctx);
-       offset += ctx_get_size(offset, lttng_ctx->event_ctx);
-
+       if (lttng_ctx) {
+               /* 2.8+ probe ABI. */
+               offset += ctx_get_size(offset, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
+               offset += ctx_get_size(offset, lttng_ctx->event_ctx, APP_CTX_ENABLED);
+       } else {
+               /* Pre 2.8 probe ABI. */
+               offset += ctx_get_size(offset, lttng_chan->ctx, APP_CTX_DISABLED);
+               offset += ctx_get_size(offset, event->ctx, APP_CTX_DISABLED);
+       }
        *pre_header_padding = padding;
        return offset - orig_offset;
 }
@@ -187,6 +239,7 @@ void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *con
                            uint32_t event_id)
 {
        struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
+       struct lttng_event *event = ctx->priv;
        struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 
        if (caa_unlikely(ctx->rflags))
@@ -222,8 +275,15 @@ void lttng_write_event_header(const struct lttng_ust_lib_ring_buffer_config *con
                WARN_ON_ONCE(1);
        }
 
-       ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx);
-       ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx);
+       if (lttng_ctx) {
+               /* 2.8+ probe ABI. */
+               ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
+               ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
+       } else {
+               /* Pre 2.8 probe ABI. */
+               ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
+               ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
+       }
        lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 
        return;
@@ -238,6 +298,7 @@ void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config
                                 uint32_t event_id)
 {
        struct lttng_channel *lttng_chan = channel_get_private(ctx->chan);
+       struct lttng_event *event = ctx->priv;
        struct lttng_stack_ctx *lttng_ctx = ctx->priv2;
 
        switch (lttng_chan->header_type) {
@@ -295,8 +356,15 @@ void lttng_write_event_header_slow(const struct lttng_ust_lib_ring_buffer_config
        default:
                WARN_ON_ONCE(1);
        }
-       ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx);
-       ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx);
+       if (lttng_ctx) {
+               /* 2.8+ probe ABI. */
+               ctx_record(ctx, lttng_chan, lttng_ctx->chan_ctx, APP_CTX_ENABLED);
+               ctx_record(ctx, lttng_chan, lttng_ctx->event_ctx, APP_CTX_ENABLED);
+       } else {
+               /* Pre 2.8 probe ABI. */
+               ctx_record(ctx, lttng_chan, lttng_chan->ctx, APP_CTX_DISABLED);
+               ctx_record(ctx, lttng_chan, event->ctx, APP_CTX_DISABLED);
+       }
        lib_ring_buffer_align_ctx(ctx, ctx->largest_align);
 }
 
@@ -647,8 +715,16 @@ int lttng_event_reserve(struct lttng_ust_lib_ring_buffer_ctx *ctx,
        }
 
        ret = lib_ring_buffer_reserve(&client_config, ctx);
-       if (ret)
+       if (caa_unlikely(ret))
                goto put;
+       if (caa_likely(ctx->ctx_len
+                       >= sizeof(struct lttng_ust_lib_ring_buffer_ctx))) {
+               if (lib_ring_buffer_backend_get_pages(&client_config, ctx,
+                               &ctx->backend_pages)) {
+                       ret = -EPERM;
+                       goto put;
+               }
+       }
        lttng_write_event_header(&client_config, ctx, event_id);
        return 0;
 put: