[lttng-ust.git] / liblttng-ust / trigger-notification.c

/*
 * trigger-notification.c
 *
 * 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 _GNU_SOURCE
#define _LGPL_SOURCE

#include <assert.h>
#include <byteswap.h>
#include <errno.h>
#include <lttng/ust-events.h>
#include <usterr-signal-safe.h>

#include "../libmsgpack/msgpack.h"
#include "lttng-bytecode.h"
#include "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_trigger_notification) - 1)

struct lttng_trigger_notification {
	int notification_fd;
	uint64_t trigger_id;
	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_trigger_notification *notif,
		struct lttng_trigger *trigger)
{
	struct lttng_msgpack_writer *writer = &notif->writer;

	notif->trigger_id = trigger->id;
	notif->notification_fd = trigger->group->notification_fd;
	notif->has_captures = false;

	if (trigger->num_captures > 0) {
		lttng_msgpack_writer_init(writer, notif->capture_buf,
				CAPTURE_BUFFER_SIZE);

		lttng_msgpack_begin_array(writer, trigger->num_captures);
		notif->has_captures = true;
	}
}

static
void notification_append_capture(
		struct lttng_trigger_notification *notif,
		struct lttng_interpreter_output *output)
{
	struct lttng_msgpack_writer *writer = &notif->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_trigger_notification *notif)
{
	lttng_msgpack_write_nil(&notif->writer);
}

static
void notification_send(struct lttng_trigger_notification *notif)
{
	ssize_t ret;
	size_t content_len;
	int iovec_count = 1;
	struct lttng_ust_trigger_notification ust_notif;
	struct iovec iov[2];

	assert(notif);

	ust_notif.id = notif->trigger_id;

	/*
	 * 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 trigger notification without blocking: %s",
				strerror(errno));
		} else {
			DBG("Error to sending trigger notification: %s",
				strerror(errno));
			abort();
		}
	}
}

void lttng_trigger_notification_send(struct lttng_trigger *trigger,
		const char *stack_data)
{
	/*
	 * This function is called from the probe, we must do dynamic
	 * allocation in this context.
	 */
	struct lttng_trigger_notification notif = {0};

	notification_init(&notif, trigger);

	if (caa_unlikely(!cds_list_empty(&trigger->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,
				&trigger->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(&notif, &output);
			else
				notification_append_empty_capture(&notif);
		}
	}

	/*
	 * Send the notification (including the capture buffer) to the
	 * sessiond.
	 */
	notification_send(&notif);
}
Commit	Line	Data
cb11f03a FD	1	/*
	2	* trigger-notification.c
	3	*
	4	* Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
	5	*
	6	* This library is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU Lesser General Public
	8	* License as published by the Free Software Foundation; only
	9	* version 2.1 of the License.
	10	*
	11	* This library is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* Lesser General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU Lesser General Public
	17	* License along with this library; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	19	*/
	20
	21	#define _GNU_SOURCE
	22	#define _LGPL_SOURCE
	23
	24	#include <assert.h>
	25	#include <byteswap.h>
	26	#include <errno.h>
	27	#include <lttng/ust-events.h>
	28	#include <usterr-signal-safe.h>
	29
	30	#include "../libmsgpack/msgpack.h"
	31	#include "lttng-bytecode.h"
	32	#include "share.h"
	33
	34	/*
	35	* We want this write to be atomic AND non-blocking, meaning that we
	36	* want to write either everything OR nothing.
	37	* According to `pipe(7)`, writes that are less than `PIPE_BUF` bytes must be
	38	* atomic, so we bound the capture buffer size to the `PIPE_BUF` minus the size
	39	* of the notification struct we are sending alongside the capture buffer.
	40	*/
	41	#define CAPTURE_BUFFER_SIZE \
	42	(PIPE_BUF - sizeof(struct lttng_ust_trigger_notification) - 1)
	43
	44	struct lttng_trigger_notification {
	45	int notification_fd;
	46	uint64_t trigger_id;
	47	uint8_t capture_buf[CAPTURE_BUFFER_SIZE];
	48	struct lttng_msgpack_writer writer;
	49	bool has_captures;
	50	};
	51
	52	static
	53	void capture_enum(struct lttng_msgpack_writer *writer,
	54	struct lttng_interpreter_output *output)
	55	{
	56	lttng_msgpack_begin_map(writer, 2);
	57	lttng_msgpack_write_str(writer, "type");
	58	lttng_msgpack_write_str(writer, "enum");
	59
	60	lttng_msgpack_write_str(writer, "value");
	61
	62	switch (output->type) {
	63	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
	64	lttng_msgpack_write_signed_integer(writer, output->u.s);
65	break;
66	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
67	lttng_msgpack_write_signed_integer(writer, output->u.u);
68	break;
69	default:
70	abort();
71	}
72
73	lttng_msgpack_end_map(writer);
74	}
75
76	static
77	int64_t capture_sequence_element_signed(uint8_t *ptr,
78	const struct lttng_integer_type *type)
79	{
80	int64_t value;
81	unsigned int size = type->size;
82	bool byte_order_reversed = type->reverse_byte_order;
83
84	switch (size) {
85	case 8:
86	value = *ptr;
87	break;
88	case 16:
89	{
90	int16_t tmp;
91	tmp = (int16_t ) ptr;
92	if (byte_order_reversed)
93	tmp = bswap_16(tmp);
94
95	value = tmp;
96	break;
97	}
98	case 32:
99	{
100	int32_t tmp;
101	tmp = (int32_t ) ptr;
102	if (byte_order_reversed)
103	tmp = bswap_32(tmp);
104
105	value = tmp;
106	break;
107	}
108	case 64:
109	{
110	int64_t tmp;
111	tmp = (int64_t ) ptr;
112	if (byte_order_reversed)
113	tmp = bswap_64(tmp);
114
115	value = tmp;
116	break;
117	}
118	default:
119	abort();
120	}
121
122	return value;
123	}
124
125	static
126	uint64_t capture_sequence_element_unsigned(uint8_t *ptr,
127	const struct lttng_integer_type *type)
128	{
129	uint64_t value;
130	unsigned int size = type->size;
131	bool byte_order_reversed = type->reverse_byte_order;
132
133	switch (size) {
134	case 8:
135	value = *ptr;
136	break;
137	case 16:
138	{
139	uint16_t tmp;
140	tmp = (uint16_t ) ptr;
141	if (byte_order_reversed)
142	tmp = bswap_16(tmp);
143
144	value = tmp;
145	break;
146	}
147	case 32:
148	{
149	uint32_t tmp;
150	tmp = (uint32_t ) ptr;
151	if (byte_order_reversed)
152	tmp = bswap_32(tmp);
153
154	value = tmp;
155	break;
156	}
157	case 64:
158	{
159	uint64_t tmp;
160	tmp = (uint64_t ) ptr;
161	if (byte_order_reversed)
162	tmp = bswap_64(tmp);
163
164	value = tmp;
165	break;
166	}
167	default:
168	abort();
169	}
170
171	return value;
172	}
173
174	static
175	void capture_sequence(struct lttng_msgpack_writer *writer,
176	struct lttng_interpreter_output *output)
177	{
178	const struct lttng_integer_type *integer_type;
179	const struct lttng_type *nested_type;
180	uint8_t *ptr;
181	bool signedness;
182	int i;
183
184	lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem);
185
186	ptr = (uint8_t *) output->u.sequence.ptr;
187	nested_type = output->u.sequence.nested_type;
188	switch (nested_type->atype) {
189	case atype_integer:
190	integer_type = &nested_type->u.integer;
191	break;
192	case atype_enum:
193	/* Treat enumeration as an integer. */
194	integer_type = &nested_type->u.enum_nestable.container_type->u.integer;
195	break;
196	default:
197	/* Capture of array of non-integer are not supported. */
198	abort();
199	}
200	signedness = integer_type->signedness;
201	for (i = 0; i < output->u.sequence.nr_elem; i++) {
202	if (signedness) {
203	lttng_msgpack_write_signed_integer(writer,
204	capture_sequence_element_signed(ptr, integer_type));
205	} else {
206	lttng_msgpack_write_unsigned_integer(writer,
207	capture_sequence_element_unsigned(ptr, integer_type));
208	}
209
210	/*
211	* We assume that alignment is smaller or equal to the size.
212	* This currently holds true but if it changes in the future,
213	* we will want to change the pointer arithmetics below to
214	* take into account that the next element might be further
215	* away.
216	*/
217	assert(integer_type->alignment <= integer_type->size);
218
219	/* Size is in number of bits. */
220	ptr += (integer_type->size / CHAR_BIT) ;
221	}
222
223	lttng_msgpack_end_array(writer);
224	}
225
226	static
227	void notification_init(struct lttng_trigger_notification *notif,
228	struct lttng_trigger *trigger)
229	{
230	struct lttng_msgpack_writer *writer = &notif->writer;
231
232	notif->trigger_id = trigger->id;
233	notif->notification_fd = trigger->group->notification_fd;
234	notif->has_captures = false;
235
236	if (trigger->num_captures > 0) {
237	lttng_msgpack_writer_init(writer, notif->capture_buf,
238	CAPTURE_BUFFER_SIZE);
239
240	lttng_msgpack_begin_array(writer, trigger->num_captures);
241	notif->has_captures = true;
242	}
243	}
244
245	static
246	void notification_append_capture(
247	struct lttng_trigger_notification *notif,
248	struct lttng_interpreter_output *output)
249	{
250	struct lttng_msgpack_writer *writer = &notif->writer;
251
252	switch (output->type) {
253	case LTTNG_INTERPRETER_TYPE_S64:
254	lttng_msgpack_write_signed_integer(writer, output->u.s);
255	break;
256	case LTTNG_INTERPRETER_TYPE_U64:
257	lttng_msgpack_write_unsigned_integer(writer, output->u.u);
258	break;
259	case LTTNG_INTERPRETER_TYPE_DOUBLE:
260	lttng_msgpack_write_double(writer, output->u.d);
261	break;
262	case LTTNG_INTERPRETER_TYPE_STRING:
263	lttng_msgpack_write_str(writer, output->u.str.str);
264	break;
265	case LTTNG_INTERPRETER_TYPE_SEQUENCE:
266	capture_sequence(writer, output);
267	break;
268	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
269	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
270	capture_enum(writer, output);
271	break;
272	default:
273	abort();
274	}
275	}
276
277	static
278	void notification_append_empty_capture(
279	struct lttng_trigger_notification *notif)
280	{
281	lttng_msgpack_write_nil(&notif->writer);
282	}
283
284	static
285	void notification_send(struct lttng_trigger_notification *notif)
286	{
287	ssize_t ret;
288	size_t content_len;
289	int iovec_count = 1;
290	struct lttng_ust_trigger_notification ust_notif;
291	struct iovec iov[2];
292
293	assert(notif);
294
295	ust_notif.id = notif->trigger_id;
296
297	/*
298	* Prepare sending the notification from multiple buffers using an
299	* array of `struct iovec`. The first buffer of the vector is
300	* notification structure itself and is always present.
301	*/
302	iov[0].iov_base = &ust_notif;
303	iov[0].iov_len = sizeof(ust_notif);
304
305	if (notif->has_captures) {
306	/*
307	* If captures were requested, the second buffer of the array
308	* is the capture buffer.
309	*/
310	assert(notif->writer.buffer);
311	content_len = notif->writer.write_pos - notif->writer.buffer;
312
313	assert(content_len > 0 && content_len <= CAPTURE_BUFFER_SIZE);
314
315	iov[1].iov_base = notif->capture_buf;
316	iov[1].iov_len = content_len;
317
318	iovec_count++;
319	} else {
320	content_len = 0;
321	}
322
323	/*
324	* Update the capture buffer size so that receiver of the buffer will
325	* know how much to expect.
326	*/
327	ust_notif.capture_buf_size = content_len;
328
329	/* Send all the buffers. */
330	ret = patient_writev(notif->notification_fd, iov, iovec_count);
331	if (ret == -1) {
332	if (errno == EAGAIN) {
333	DBG("Cannot send trigger notification without blocking: %s",
334	strerror(errno));
335	} else {
336	DBG("Error to sending trigger notification: %s",
337	strerror(errno));
338	abort();
339	}
340	}
341	}
342
343	void lttng_trigger_notification_send(struct lttng_trigger *trigger,
344	const char *stack_data)
345	{
346	/*
347	* This function is called from the probe, we must do dynamic
348	* allocation in this context.
349	*/
350	struct lttng_trigger_notification notif = {0};
351
352	notification_init(&notif, trigger);
353
354	if (caa_unlikely(!cds_list_empty(&trigger->capture_bytecode_runtime_head))) {
355	struct lttng_bytecode_runtime *capture_bc_runtime;
356
357	/*
358	* Iterate over all the capture bytecodes. If the interpreter
359	* functions returns successfully, append the value of the
360	* `output` parameter to the capture buffer. If the interpreter
361	* fails, append an empty capture to the buffer.
362	*/
363	cds_list_for_each_entry(capture_bc_runtime,
364	&trigger->capture_bytecode_runtime_head, node) {
365	struct lttng_interpreter_output output;
366
367	if (capture_bc_runtime->interpreter_funcs.capture(capture_bc_runtime,
368	stack_data, &output) & LTTNG_INTERPRETER_RECORD_FLAG)
369	notification_append_capture(&notif, &output);
370	else
371	notification_append_empty_capture(&notif);
372	}
373	}
374
375	/*
376	* Send the notification (including the capture buffer) to the
377	* sessiond.
378	*/
379	notification_send(&notif);
380	}