+++ /dev/null
-/*
- * SPDX-License-Identifier: LGPL-2.1-only
- *
- * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
- */
-
-#define _LGPL_SOURCE
-
-#include <assert.h>
-#include <errno.h>
-#include <limits.h>
-
-#include <lttng/ust-endian.h>
-#include <usterr-signal-safe.h>
-#include <urcu/rculist.h>
-
-#include "lttng-tracer-core.h"
-#include "ust-events-internal.h"
-#include "../libmsgpack/msgpack.h"
-#include "lttng-bytecode.h"
-#include "ust-share.h"
-
-/*
- * We want this write to be atomic AND non-blocking, meaning that we
- * want to write either everything OR nothing.
- * According to `pipe(7)`, writes that are less than `PIPE_BUF` bytes must be
- * atomic, so we bound the capture buffer size to the `PIPE_BUF` minus the size
- * of the notification struct we are sending alongside the capture buffer.
- */
-#define CAPTURE_BUFFER_SIZE \
- (PIPE_BUF - sizeof(struct lttng_ust_abi_event_notifier_notification) - 1)
-
-struct lttng_event_notifier_notification {
- int notification_fd;
- uint64_t event_notifier_token;
- uint8_t capture_buf[CAPTURE_BUFFER_SIZE];
- struct lttng_msgpack_writer writer;
- bool has_captures;
-};
-
-static
-void capture_enum(struct lttng_msgpack_writer *writer,
- struct lttng_interpreter_output *output)
-{
- lttng_msgpack_begin_map(writer, 2);
- lttng_msgpack_write_str(writer, "type");
- lttng_msgpack_write_str(writer, "enum");
-
- lttng_msgpack_write_str(writer, "value");
-
- switch (output->type) {
- case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
- lttng_msgpack_write_signed_integer(writer, output->u.s);
- break;
- case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
- lttng_msgpack_write_signed_integer(writer, output->u.u);
- break;
- default:
- abort();
- }
-
- lttng_msgpack_end_map(writer);
-}
-
-static
-int64_t capture_sequence_element_signed(uint8_t *ptr,
- const struct lttng_ust_type_integer *integer_type)
-{
- int64_t value;
- unsigned int size = integer_type->size;
- bool byte_order_reversed = integer_type->reverse_byte_order;
-
- switch (size) {
- case 8:
- value = *ptr;
- break;
- case 16:
- {
- int16_t tmp;
- tmp = *(int16_t *) ptr;
- if (byte_order_reversed)
- tmp = bswap_16(tmp);
-
- value = tmp;
- break;
- }
- case 32:
- {
- int32_t tmp;
- tmp = *(int32_t *) ptr;
- if (byte_order_reversed)
- tmp = bswap_32(tmp);
-
- value = tmp;
- break;
- }
- case 64:
- {
- int64_t tmp;
- tmp = *(int64_t *) ptr;
- if (byte_order_reversed)
- tmp = bswap_64(tmp);
-
- value = tmp;
- break;
- }
- default:
- abort();
- }
-
- return value;
-}
-
-static
-uint64_t capture_sequence_element_unsigned(uint8_t *ptr,
- const struct lttng_ust_type_integer *integer_type)
-{
- uint64_t value;
- unsigned int size = integer_type->size;
- bool byte_order_reversed = integer_type->reverse_byte_order;
-
- switch (size) {
- case 8:
- value = *ptr;
- break;
- case 16:
- {
- uint16_t tmp;
- tmp = *(uint16_t *) ptr;
- if (byte_order_reversed)
- tmp = bswap_16(tmp);
-
- value = tmp;
- break;
- }
- case 32:
- {
- uint32_t tmp;
- tmp = *(uint32_t *) ptr;
- if (byte_order_reversed)
- tmp = bswap_32(tmp);
-
- value = tmp;
- break;
- }
- case 64:
- {
- uint64_t tmp;
- tmp = *(uint64_t *) ptr;
- if (byte_order_reversed)
- tmp = bswap_64(tmp);
-
- value = tmp;
- break;
- }
- default:
- abort();
- }
-
- return value;
-}
-
-static
-void capture_sequence(struct lttng_msgpack_writer *writer,
- struct lttng_interpreter_output *output)
-{
- const struct lttng_ust_type_integer *integer_type;
- const struct lttng_ust_type_common *nested_type;
- uint8_t *ptr;
- bool signedness;
- int i;
-
- lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem);
-
- ptr = (uint8_t *) output->u.sequence.ptr;
- nested_type = output->u.sequence.nested_type;
- switch (nested_type->type) {
- case lttng_ust_type_integer:
- integer_type = lttng_ust_get_type_integer(nested_type);
- break;
- case lttng_ust_type_enum:
- /* Treat enumeration as an integer. */
- integer_type = lttng_ust_get_type_integer(lttng_ust_get_type_enum(nested_type)->container_type);
- break;
- default:
- /* Capture of array of non-integer are not supported. */
- abort();
- }
- signedness = integer_type->signedness;
- for (i = 0; i < output->u.sequence.nr_elem; i++) {
- if (signedness) {
- lttng_msgpack_write_signed_integer(writer,
- capture_sequence_element_signed(ptr, integer_type));
- } else {
- lttng_msgpack_write_unsigned_integer(writer,
- capture_sequence_element_unsigned(ptr, integer_type));
- }
-
- /*
- * We assume that alignment is smaller or equal to the size.
- * This currently holds true but if it changes in the future,
- * we will want to change the pointer arithmetics below to
- * take into account that the next element might be further
- * away.
- */
- assert(integer_type->alignment <= integer_type->size);
-
- /* Size is in number of bits. */
- ptr += (integer_type->size / CHAR_BIT) ;
- }
-
- lttng_msgpack_end_array(writer);
-}
-
-static
-void notification_init(struct lttng_event_notifier_notification *notif,
- struct lttng_ust_event_notifier *event_notifier)
-{
- struct lttng_msgpack_writer *writer = ¬if->writer;
-
- notif->event_notifier_token = event_notifier->priv->parent.user_token;
- notif->notification_fd = event_notifier->priv->group->notification_fd;
- notif->has_captures = false;
-
- if (event_notifier->priv->num_captures > 0) {
- lttng_msgpack_writer_init(writer, notif->capture_buf,
- CAPTURE_BUFFER_SIZE);
-
- lttng_msgpack_begin_array(writer, event_notifier->priv->num_captures);
- notif->has_captures = true;
- }
-}
-
-static
-void notification_append_capture(
- struct lttng_event_notifier_notification *notif,
- struct lttng_interpreter_output *output)
-{
- struct lttng_msgpack_writer *writer = ¬if->writer;
-
- switch (output->type) {
- case LTTNG_INTERPRETER_TYPE_S64:
- lttng_msgpack_write_signed_integer(writer, output->u.s);
- break;
- case LTTNG_INTERPRETER_TYPE_U64:
- lttng_msgpack_write_unsigned_integer(writer, output->u.u);
- break;
- case LTTNG_INTERPRETER_TYPE_DOUBLE:
- lttng_msgpack_write_double(writer, output->u.d);
- break;
- case LTTNG_INTERPRETER_TYPE_STRING:
- lttng_msgpack_write_str(writer, output->u.str.str);
- break;
- case LTTNG_INTERPRETER_TYPE_SEQUENCE:
- capture_sequence(writer, output);
- break;
- case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
- case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
- capture_enum(writer, output);
- break;
- default:
- abort();
- }
-}
-
-static
-void notification_append_empty_capture(
- struct lttng_event_notifier_notification *notif)
-{
- lttng_msgpack_write_nil(¬if->writer);
-}
-
-static void record_error(struct lttng_ust_event_notifier *event_notifier)
-{
- struct lttng_event_notifier_group *event_notifier_group =
- event_notifier->priv->group;
- struct lttng_counter *error_counter;
- size_t dimension_index[1];
- int ret;
-
- error_counter = CMM_LOAD_SHARED(event_notifier_group->error_counter);
- /*
- * load-acquire paired with store-release orders creation of the
- * error counter and setting error_counter_len before the
- * error_counter is used.
- * Currently a full memory barrier is used, which could be
- * turned into acquire-release barriers.
- */
- cmm_smp_mb();
- /* This group may not have an error counter attached to it. */
- if (!error_counter)
- return;
-
- dimension_index[0] = event_notifier->priv->error_counter_index;
- ret = event_notifier_group->error_counter->ops->counter_add(
- error_counter->counter, dimension_index, 1);
- if (ret)
- WARN_ON_ONCE(1);
-}
-
-static
-void notification_send(struct lttng_event_notifier_notification *notif,
- struct lttng_ust_event_notifier *event_notifier)
-{
- ssize_t ret;
- size_t content_len;
- int iovec_count = 1;
- struct lttng_ust_abi_event_notifier_notification ust_notif = {0};
- struct iovec iov[2];
-
- assert(notif);
-
- ust_notif.token = event_notifier->priv->parent.user_token;
-
- /*
- * Prepare sending the notification from multiple buffers using an
- * array of `struct iovec`. The first buffer of the vector is
- * notification structure itself and is always present.
- */
- iov[0].iov_base = &ust_notif;
- iov[0].iov_len = sizeof(ust_notif);
-
- if (notif->has_captures) {
- /*
- * If captures were requested, the second buffer of the array
- * is the capture buffer.
- */
- assert(notif->writer.buffer);
- content_len = notif->writer.write_pos - notif->writer.buffer;
-
- assert(content_len > 0 && content_len <= CAPTURE_BUFFER_SIZE);
-
- iov[1].iov_base = notif->capture_buf;
- iov[1].iov_len = content_len;
-
- iovec_count++;
- } else {
- content_len = 0;
- }
-
- /*
- * Update the capture buffer size so that receiver of the buffer will
- * know how much to expect.
- */
- ust_notif.capture_buf_size = content_len;
-
- /* Send all the buffers. */
- ret = ust_patient_writev(notif->notification_fd, iov, iovec_count);
- if (ret == -1) {
- if (errno == EAGAIN) {
- record_error(event_notifier);
- DBG("Cannot send event_notifier notification without blocking: %s",
- strerror(errno));
- } else {
- DBG("Error to sending event notifier notification: %s",
- strerror(errno));
- abort();
- }
- }
-}
-
-void lttng_event_notifier_notification_send(
- struct lttng_ust_event_notifier *event_notifier,
- const char *stack_data,
- struct lttng_ust_notification_ctx *notif_ctx)
-{
- /*
- * This function is called from the probe, we must do dynamic
- * allocation in this context.
- */
- struct lttng_event_notifier_notification notif = {0};
-
- notification_init(¬if, event_notifier);
-
- if (caa_unlikely(notif_ctx->eval_capture)) {
- struct lttng_ust_bytecode_runtime *capture_bc_runtime;
-
- /*
- * Iterate over all the capture bytecodes. If the interpreter
- * functions returns successfully, append the value of the
- * `output` parameter to the capture buffer. If the interpreter
- * fails, append an empty capture to the buffer.
- */
- cds_list_for_each_entry_rcu(capture_bc_runtime,
- &event_notifier->priv->capture_bytecode_runtime_head, node) {
- struct lttng_interpreter_output output;
-
- if (capture_bc_runtime->interpreter_func(capture_bc_runtime,
- stack_data, &output) == LTTNG_UST_BYTECODE_INTERPRETER_OK)
- notification_append_capture(¬if, &output);
- else
- notification_append_empty_capture(¬if);
- }
- }
-
- /*
- * Send the notification (including the capture buffer) to the
- * sessiond.
- */
- notification_send(¬if, event_notifier);
-}
projects / lttng-ust.git / blobdiff