/*
- * event-notifier-notification.c
+ * SPDX-License-Identifier: LGPL-2.1-only
*
* Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define _LGPL_SOURCE
+#include <assert.h>
#include <errno.h>
#include <lttng/ust-events.h>
+#include <lttng/ust-endian.h>
#include <usterr-signal-safe.h>
+#include "../libmsgpack/msgpack.h"
+#include "lttng-bytecode.h"
#include "share.h"
-void lttng_event_notifier_notification_send(
+/*
+ * 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_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_integer_type *type)
+{
+ int64_t value;
+ unsigned int size = type->size;
+ bool byte_order_reversed = 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_integer_type *type)
+{
+ uint64_t value;
+ unsigned int size = type->size;
+ bool byte_order_reversed = 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_integer_type *integer_type;
+ const struct lttng_type *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->atype) {
+ case atype_integer:
+ integer_type = &nested_type->u.integer;
+ break;
+ case atype_enum:
+ /* Treat enumeration as an integer. */
+ integer_type = &nested_type->u.enum_nestable.container_type->u.integer;
+ 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_event_notifier *event_notifier)
{
+ struct lttng_msgpack_writer *writer = ¬if->writer;
+
+ notif->event_notifier_token = event_notifier->user_token;
+ notif->notification_fd = event_notifier->group->notification_fd;
+ notif->has_captures = false;
+
+ if (event_notifier->num_captures > 0) {
+ lttng_msgpack_writer_init(writer, notif->capture_buf,
+ CAPTURE_BUFFER_SIZE);
+
+ lttng_msgpack_begin_array(writer, event_notifier->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_event_notifier *event_notifier)
+{
+ struct lttng_event_notifier_group *event_notifier_group =
+ event_notifier->group;
+ struct lttng_counter *error_counter;
+ size_t dimension_index[1];
+ int ret;
+
+ error_counter = CMM_LOAD_SHARED(event_notifier_group->error_counter);
/*
- * 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 smaller that the `PIPE_BUF`
- * value must be atomic, so we assert that the message we send is less
- * than PIPE_BUF.
+ * 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.
*/
- struct lttng_ust_event_notifier_notification notif;
+ cmm_smp_mb();
+ /* This group may not have an error counter attached to it. */
+ if (!error_counter)
+ return;
+
+ dimension_index[0] = event_notifier->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_event_notifier *event_notifier)
+{
ssize_t ret;
+ size_t content_len;
+ int iovec_count = 1;
+ struct lttng_ust_event_notifier_notification ust_notif = {0};
+ struct iovec iov[2];
- assert(event_notifier);
- assert(event_notifier->group);
- assert(sizeof(notif) <= PIPE_BUF);
+ assert(notif);
- notif.token = event_notifier->user_token;
+ ust_notif.token = event_notifier->user_token;
- ret = patient_write(event_notifier->group->notification_fd, ¬if,
- sizeof(notif));
+ /*
+ * 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 = patient_writev(notif->notification_fd, iov, iovec_count);
if (ret == -1) {
if (errno == EAGAIN) {
- DBG("Cannot send event notifier notification without blocking: %s",
+ record_error(event_notifier);
+ DBG("Cannot send event_notifier notification without blocking: %s",
strerror(errno));
} else {
DBG("Error to sending event notifier notification: %s",
}
}
}
+
+void lttng_event_notifier_notification_send(
+ struct lttng_event_notifier *event_notifier,
+ const char *stack_data)
+{
+ /*
+ * 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(!cds_list_empty(&event_notifier->capture_bytecode_runtime_head))) {
+ struct lttng_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(capture_bc_runtime,
+ &event_notifier->capture_bytecode_runtime_head, node) {
+ struct lttng_interpreter_output output;
+
+ if (capture_bc_runtime->interpreter_funcs.capture(capture_bc_runtime,
+ stack_data, &output) & LTTNG_INTERPRETER_RECORD_FLAG)
+ 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