[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c

/*
 * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
 *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define _GNU_SOURCE
#include <assert.h>
#include <poll.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <lttng/ust-ctl.h>

#include <common/common.h>
#include <common/sessiond-comm/sessiond-comm.h>
#include <common/compat/fcntl.h>

#include "ust-consumer.h"

extern struct lttng_consumer_global_data consumer_data;
extern int consumer_poll_timeout;
extern volatile int consumer_quit;

/*
 * Mmap the ring buffer, read it and write the data to the tracefile.
 *
 * Returns the number of bytes written, else negative value on error.
 */
ssize_t lttng_ustconsumer_on_read_subbuffer_mmap(
		struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream, unsigned long len)
{
	unsigned long mmap_offset;
	long ret = 0;
	off_t orig_offset = stream->out_fd_offset;
	int outfd = stream->out_fd;

	/* get the offset inside the fd to mmap */
	ret = ustctl_get_mmap_read_offset(stream->chan->handle,
		stream->buf, &mmap_offset);
	if (ret != 0) {
		errno = -ret;
		PERROR("ustctl_get_mmap_read_offset");
		goto end;
	}
	while (len > 0) {
		ret = write(outfd, stream->mmap_base + mmap_offset, len);
		if (ret >= len) {
			len = 0;
		} else if (ret < 0) {
			errno = -ret;
			PERROR("Error in file write");
			goto end;
		}
		/* This won't block, but will start writeout asynchronously */
		lttng_sync_file_range(outfd, stream->out_fd_offset, ret,
				SYNC_FILE_RANGE_WRITE);
		stream->out_fd_offset += ret;
	}

	lttng_consumer_sync_trace_file(stream, orig_offset);

	goto end;

end:
	return ret;
}

/*
 * Splice the data from the ring buffer to the tracefile.
 *
 * Returns the number of bytes spliced.
 */
ssize_t lttng_ustconsumer_on_read_subbuffer_splice(
		struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream, unsigned long len)
{
	return -ENOSYS;
}

/*
 * Take a snapshot for a specific fd
 *
 * Returns 0 on success, < 0 on error
 */
int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream)
{
	int ret = 0;

	ret = ustctl_snapshot(stream->chan->handle, stream->buf);
	if (ret != 0) {
		errno = -ret;
		PERROR("Getting sub-buffer snapshot.");
	}

	return ret;
}

/*
 * Get the produced position
 *
 * Returns 0 on success, < 0 on error
 */
int lttng_ustconsumer_get_produced_snapshot(
		struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream,
		unsigned long *pos)
{
	int ret;

	ret = ustctl_snapshot_get_produced(stream->chan->handle,
			stream->buf, pos);
	if (ret != 0) {
		errno = -ret;
		PERROR("kernctl_snapshot_get_produced");
	}

	return ret;
}

int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
		int sock, struct pollfd *consumer_sockpoll)
{
	ssize_t ret;
	struct lttcomm_consumer_msg msg;

	ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
	if (ret != sizeof(msg)) {
		lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
		return ret;
	}
	if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
		return -ENOENT;
	}

	switch (msg.cmd_type) {
	case LTTNG_CONSUMER_ADD_CHANNEL:
	{
		struct lttng_consumer_channel *new_channel;
		int fds[1];
		size_t nb_fd = 1;

		/* block */
		if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
			return -EINTR;
		}
		ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
		if (ret != sizeof(fds)) {
			lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
			return ret;
		}

		DBG("consumer_add_channel %d", msg.u.channel.channel_key);

		new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
				fds[0], -1,
				msg.u.channel.mmap_len,
				msg.u.channel.max_sb_size);
		if (new_channel == NULL) {
			lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
			goto end_nosignal;
		}
		if (ctx->on_recv_channel != NULL) {
			ret = ctx->on_recv_channel(new_channel);
			if (ret == 0) {
				consumer_add_channel(new_channel);
			} else if (ret < 0) {
				goto end_nosignal;
			}
		} else {
			consumer_add_channel(new_channel);
		}
		goto end_nosignal;
	}
	case LTTNG_CONSUMER_ADD_STREAM:
	{
		struct lttng_consumer_stream *new_stream;
		int fds[2];
		size_t nb_fd = 2;

		/* block */
		if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
			return -EINTR;
		}
		ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
		if (ret != sizeof(fds)) {
			lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
			return ret;
		}

		DBG("consumer_add_stream %s (%d,%d)", msg.u.stream.path_name,
			fds[0], fds[1]);
		assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
		new_stream = consumer_allocate_stream(msg.u.channel.channel_key,
				msg.u.stream.stream_key,
				fds[0], fds[1],
				msg.u.stream.state,
				msg.u.stream.mmap_len,
				msg.u.stream.output,
				msg.u.stream.path_name,
				msg.u.stream.uid,
				msg.u.stream.gid);
		if (new_stream == NULL) {
			lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
			goto end;
		}
		if (ctx->on_recv_stream != NULL) {
			ret = ctx->on_recv_stream(new_stream);
			if (ret == 0) {
				consumer_add_stream(new_stream);
			} else if (ret < 0) {
				goto end;
			}
		} else {
			consumer_add_stream(new_stream);
		}
		break;
	}
	case LTTNG_CONSUMER_UPDATE_STREAM:
	{
		return -ENOSYS;
#if 0
		if (ctx->on_update_stream != NULL) {
			ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
			if (ret == 0) {
				consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
			} else if (ret < 0) {
				goto end;
			}
		} else {
			consumer_change_stream_state(msg.u.stream.stream_key,
				msg.u.stream.state);
		}
#endif
		break;
	}
	default:
		break;
	}
end:
	/*
	 * Wake-up the other end by writing a null byte in the pipe
	 * (non-blocking). Important note: Because writing into the
	 * pipe is non-blocking (and therefore we allow dropping wakeup
	 * data, as long as there is wakeup data present in the pipe
	 * buffer to wake up the other end), the other end should
	 * perform the following sequence for waiting:
	 * 1) empty the pipe (reads).
	 * 2) perform update operation.
	 * 3) wait on the pipe (poll).
	 */
	do {
		ret = write(ctx->consumer_poll_pipe[1], "", 1);
	} while (ret == -1UL && errno == EINTR);
end_nosignal:
	return 0;
}

int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
{
	struct lttng_ust_object_data obj;

	obj.handle = -1;
	obj.shm_fd = chan->shm_fd;
	obj.wait_fd = chan->wait_fd;
	obj.memory_map_size = chan->mmap_len;
	chan->handle = ustctl_map_channel(&obj);
	if (!chan->handle) {
		return -ENOMEM;
	}
	chan->wait_fd_is_copy = 1;
	chan->shm_fd = -1;

	return 0;
}

void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
{
	ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
	stream->hangup_flush_done = 1;
}

void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
{
	ustctl_unmap_channel(chan->handle);
}

int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
{
	struct lttng_ust_object_data obj;
	int ret;

	obj.handle = -1;
	obj.shm_fd = stream->shm_fd;
	obj.wait_fd = stream->wait_fd;
	obj.memory_map_size = stream->mmap_len;
	ret = ustctl_add_stream(stream->chan->handle, &obj);
	if (ret)
		return ret;
	stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
	if (!stream->buf)
		return -EBUSY;
	/* ustctl_open_stream_read has closed the shm fd. */
	stream->wait_fd_is_copy = 1;
	stream->shm_fd = -1;

	stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
	if (!stream->mmap_base) {
		return -EINVAL;
	}

	return 0;
}

void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
{
	ustctl_close_stream_read(stream->chan->handle, stream->buf);
}


int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
		struct lttng_consumer_local_data *ctx)
{
	unsigned long len;
	int err;
	long ret = 0;
	struct lttng_ust_shm_handle *handle;
	struct lttng_ust_lib_ring_buffer *buf;
	char dummy;
	ssize_t readlen;

	DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
		stream->wait_fd, stream->key);

	/* We can consume the 1 byte written into the wait_fd by UST */
	if (!stream->hangup_flush_done) {
		do {
			readlen = read(stream->wait_fd, &dummy, 1);
		} while (readlen == -1 && errno == EINTR);
		if (readlen == -1) {
			ret = readlen;
			goto end;
		}
	}

	buf = stream->buf;
	handle = stream->chan->handle;
	/* Get the next subbuffer */
	err = ustctl_get_next_subbuf(handle, buf);
	if (err != 0) {
		ret = -ret;	/* ustctl_get_next_subbuf returns negative, caller expect positive. */
		/*
		 * This is a debug message even for single-threaded consumer,
		 * because poll() have more relaxed criterions than get subbuf,
		 * so get_subbuf may fail for short race windows where poll()
		 * would issue wakeups.
		 */
		DBG("Reserving sub buffer failed (everything is normal, "
				"it is due to concurrency)");
		goto end;
	}
	assert(stream->output == LTTNG_EVENT_MMAP);
	/* read the used subbuffer size */
	err = ustctl_get_padded_subbuf_size(handle, buf, &len);
	assert(err == 0);
	/* write the subbuffer to the tracefile */
	ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
	if (ret < 0) {
		/*
		 * display the error but continue processing to try
		 * to release the subbuffer
		 */
		ERR("Error writing to tracefile");
	}
	err = ustctl_put_next_subbuf(handle, buf);
	assert(err == 0);
end:
	return ret;
}

int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
{
	int ret;

	/* Opening the tracefile in write mode */
	if (stream->path_name != NULL) {
		ret = run_as_open(stream->path_name,
				O_WRONLY|O_CREAT|O_TRUNC,
				S_IRWXU|S_IRWXG|S_IRWXO,
				stream->uid, stream->gid);
		if (ret < 0) {
			ERR("Opening %s", stream->path_name);
			PERROR("open");
			goto error;
		}
		stream->out_fd = ret;
	}

	/* we return 0 to let the library handle the FD internally */
	return 0;

error:
	return ret;
}
Commit	Line	Data
3bd1e081 MD	1	/*
	2	* Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
	3	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*
d14d33bf AM	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License, version 2 only,
	7	* as published by the Free Software Foundation.
3bd1e081 MD	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
d14d33bf AM	14	* You should have received a copy of the GNU General Public License along
	15	* with this program; if not, write to the Free Software Foundation, Inc.,
	16	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
3bd1e081 MD	17	*/
	18
	19	#define _GNU_SOURCE
	20	#include <assert.h>
3bd1e081 MD	21	#include <poll.h>
	22	#include <pthread.h>
	23	#include <stdlib.h>
	24	#include <string.h>
	25	#include <sys/mman.h>
	26	#include <sys/socket.h>
dbb5dfe6	27	#include <sys/stat.h>
3bd1e081 MD	28	#include <sys/types.h>
3bd1e081 MD	29	#include <unistd.h>
9df8df5e	30	#include <lttng/ust-ctl.h>
0857097f	31
990570ed	32	#include <common/common.h>
10a8a223	33	#include <common/sessiond-comm/sessiond-comm.h>
dbb5dfe6	34	#include <common/compat/fcntl.h>
10a8a223 DG	35
10a8a223 DG	36	#include "ust-consumer.h"
3bd1e081 MD	37
	38	extern struct lttng_consumer_global_data consumer_data;
	39	extern int consumer_poll_timeout;
	40	extern volatile int consumer_quit;
	41
	42	/*
	43	* Mmap the ring buffer, read it and write the data to the tracefile.
	44	*
4078b776	45	* Returns the number of bytes written, else negative value on error.
3bd1e081	46	*/
4078b776	47	ssize_t lttng_ustconsumer_on_read_subbuffer_mmap(
3bd1e081 MD	48	struct lttng_consumer_local_data *ctx,
	49	struct lttng_consumer_stream *stream, unsigned long len)
	50	{
	51	unsigned long mmap_offset;
	52	long ret = 0;
	53	off_t orig_offset = stream->out_fd_offset;
	54	int outfd = stream->out_fd;
	55
	56	/* get the offset inside the fd to mmap */
	57	ret = ustctl_get_mmap_read_offset(stream->chan->handle,
	58	stream->buf, &mmap_offset);
	59	if (ret != 0) {
87dc6a9c	60	errno = -ret;
4c462e79	61	PERROR("ustctl_get_mmap_read_offset");
3bd1e081 MD	62	goto end;
	63	}
	64	while (len > 0) {
	65	ret = write(outfd, stream->mmap_base + mmap_offset, len);
	66	if (ret >= len) {
	67	len = 0;
	68	} else if (ret < 0) {
87dc6a9c	69	errno = -ret;
4c462e79	70	PERROR("Error in file write");
3bd1e081 MD	71	goto end;
	72	}
	73	/* This won't block, but will start writeout asynchronously */
dbb5dfe6	74	lttng_sync_file_range(outfd, stream->out_fd_offset, ret,
3bd1e081 MD	75	SYNC_FILE_RANGE_WRITE);
	76	stream->out_fd_offset += ret;
	77	}
	78
	79	lttng_consumer_sync_trace_file(stream, orig_offset);
	80
	81	goto end;
	82
	83	end:
	84	return ret;
	85	}
	86
	87	/*
	88	* Splice the data from the ring buffer to the tracefile.
	89	*
	90	* Returns the number of bytes spliced.
	91	*/
4078b776	92	ssize_t lttng_ustconsumer_on_read_subbuffer_splice(
3bd1e081 MD	93	struct lttng_consumer_local_data *ctx,
	94	struct lttng_consumer_stream *stream, unsigned long len)
	95	{
	96	return -ENOSYS;
	97	}
	98
	99	/*
	100	* Take a snapshot for a specific fd
	101	*
	102	* Returns 0 on success, < 0 on error
	103	*/
	104	int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
	105	struct lttng_consumer_stream *stream)
	106	{
	107	int ret = 0;
	108
	109	ret = ustctl_snapshot(stream->chan->handle, stream->buf);
	110	if (ret != 0) {
87dc6a9c	111	errno = -ret;
4c462e79	112	PERROR("Getting sub-buffer snapshot.");
3bd1e081 MD	113	}
	114
	115	return ret;
	116	}
	117
	118	/*
	119	* Get the produced position
	120	*
	121	* Returns 0 on success, < 0 on error
	122	*/
	123	int lttng_ustconsumer_get_produced_snapshot(
	124	struct lttng_consumer_local_data *ctx,
	125	struct lttng_consumer_stream *stream,
	126	unsigned long *pos)
	127	{
	128	int ret;
	129
	130	ret = ustctl_snapshot_get_produced(stream->chan->handle,
	131	stream->buf, pos);
	132	if (ret != 0) {
87dc6a9c	133	errno = -ret;
4c462e79	134	PERROR("kernctl_snapshot_get_produced");
3bd1e081 MD	135	}
	136
	137	return ret;
	138	}
	139
	140	int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
	141	int sock, struct pollfd *consumer_sockpoll)
	142	{
	143	ssize_t ret;
	144	struct lttcomm_consumer_msg msg;
	145
	146	ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
	147	if (ret != sizeof(msg)) {
	148	lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
	149	return ret;
	150	}
	151	if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
	152	return -ENOENT;
	153	}
	154
	155	switch (msg.cmd_type) {
	156	case LTTNG_CONSUMER_ADD_CHANNEL:
	157	{
	158	struct lttng_consumer_channel *new_channel;
	159	int fds[1];
	160	size_t nb_fd = 1;
	161
	162	/* block */
	163	if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
	164	return -EINTR;
	165	}
	166	ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
	167	if (ret != sizeof(fds)) {
	168	lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
	169	return ret;
	170	}
	171
	172	DBG("consumer_add_channel %d", msg.u.channel.channel_key);
	173
	174	new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
	175	fds[0], -1,
	176	msg.u.channel.mmap_len,
	177	msg.u.channel.max_sb_size);
	178	if (new_channel == NULL) {
	179	lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
	180	goto end_nosignal;
	181	}
	182	if (ctx->on_recv_channel != NULL) {
	183	ret = ctx->on_recv_channel(new_channel);
	184	if (ret == 0) {
	185	consumer_add_channel(new_channel);
	186	} else if (ret < 0) {
	187	goto end_nosignal;
	188	}
	189	} else {
	190	consumer_add_channel(new_channel);
	191	}
	192	goto end_nosignal;
	193	}
	194	case LTTNG_CONSUMER_ADD_STREAM:
	195	{
	196	struct lttng_consumer_stream *new_stream;
	197	int fds[2];
	198	size_t nb_fd = 2;
199
200	/* block */
201	if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
202	return -EINTR;
203	}
204	ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
205	if (ret != sizeof(fds)) {
206	lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
207	return ret;
208	}
209
210	DBG("consumer_add_stream %s (%d,%d)", msg.u.stream.path_name,
211	fds[0], fds[1]);
d41f73b7	212	assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
7ad0a0cb	213	new_stream = consumer_allocate_stream(msg.u.channel.channel_key,
3bd1e081 MD	214	msg.u.stream.stream_key,
	215	fds[0], fds[1],
	216	msg.u.stream.state,
	217	msg.u.stream.mmap_len,
	218	msg.u.stream.output,
6df2e2c9 MD	219	msg.u.stream.path_name,
	220	msg.u.stream.uid,
	221	msg.u.stream.gid);
3bd1e081 MD	222	if (new_stream == NULL) {
	223	lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
	224	goto end;
	225	}
	226	if (ctx->on_recv_stream != NULL) {
	227	ret = ctx->on_recv_stream(new_stream);
	228	if (ret == 0) {
	229	consumer_add_stream(new_stream);
	230	} else if (ret < 0) {
	231	goto end;
	232	}
	233	} else {
	234	consumer_add_stream(new_stream);
	235	}
	236	break;
	237	}
	238	case LTTNG_CONSUMER_UPDATE_STREAM:
	239	{
7ad0a0cb MD	240	return -ENOSYS;
7ad0a0cb MD	241	#if 0
3bd1e081 MD	242	if (ctx->on_update_stream != NULL) {
	243	ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
	244	if (ret == 0) {
	245	consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
	246	} else if (ret < 0) {
	247	goto end;
	248	}
	249	} else {
	250	consumer_change_stream_state(msg.u.stream.stream_key,
	251	msg.u.stream.state);
	252	}
7ad0a0cb	253	#endif
3bd1e081 MD	254	break;
	255	}
	256	default:
	257	break;
	258	}
	259	end:
04fdd819 MD	260	/*
	261	* Wake-up the other end by writing a null byte in the pipe
	262	* (non-blocking). Important note: Because writing into the
	263	* pipe is non-blocking (and therefore we allow dropping wakeup
	264	* data, as long as there is wakeup data present in the pipe
	265	* buffer to wake up the other end), the other end should
	266	* perform the following sequence for waiting:
	267	* 1) empty the pipe (reads).
	268	* 2) perform update operation.
	269	* 3) wait on the pipe (poll).
	270	*/
	271	do {
	272	ret = write(ctx->consumer_poll_pipe[1], "", 1);
	273	} while (ret == -1UL && errno == EINTR);
3bd1e081 MD	274	end_nosignal:
	275	return 0;
	276	}
	277
	278	int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
	279	{
13161846	280	struct lttng_ust_object_data obj;
3bd1e081 MD	281
	282	obj.handle = -1;
	283	obj.shm_fd = chan->shm_fd;
	284	obj.wait_fd = chan->wait_fd;
	285	obj.memory_map_size = chan->mmap_len;
	286	chan->handle = ustctl_map_channel(&obj);
	287	if (!chan->handle) {
	288	return -ENOMEM;
	289	}
b5c5fc29	290	chan->wait_fd_is_copy = 1;
2c1dd183	291	chan->shm_fd = -1;
b5c5fc29	292
3bd1e081 MD	293	return 0;
	294	}
	295
d056b477 MD	296	void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
	297	{
	298	ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
effcf122	299	stream->hangup_flush_done = 1;
d056b477 MD	300	}
d056b477 MD	301
3bd1e081 MD	302	void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
	303	{
	304	ustctl_unmap_channel(chan->handle);
	305	}
	306
	307	int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
	308	{
13161846	309	struct lttng_ust_object_data obj;
3bd1e081 MD	310	int ret;
	311
	312	obj.handle = -1;
	313	obj.shm_fd = stream->shm_fd;
	314	obj.wait_fd = stream->wait_fd;
	315	obj.memory_map_size = stream->mmap_len;
	316	ret = ustctl_add_stream(stream->chan->handle, &obj);
	317	if (ret)
	318	return ret;
	319	stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
	320	if (!stream->buf)
	321	return -EBUSY;
2c1dd183 MD	322	/* ustctl_open_stream_read has closed the shm fd. */
	323	stream->wait_fd_is_copy = 1;
	324	stream->shm_fd = -1;
	325
3bd1e081 MD	326	stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
	327	if (!stream->mmap_base) {
	328	return -EINVAL;
	329	}
ee77a7b0	330
3bd1e081 MD	331	return 0;
	332	}
	333
	334	void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
	335	{
	336	ustctl_close_stream_read(stream->chan->handle, stream->buf);
	337	}
d41f73b7 MD	338
	339
	340	int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
	341	struct lttng_consumer_local_data *ctx)
	342	{
	343	unsigned long len;
	344	int err;
	345	long ret = 0;
	346	struct lttng_ust_shm_handle *handle;
	347	struct lttng_ust_lib_ring_buffer *buf;
	348	char dummy;
	349	ssize_t readlen;
	350
	351	DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
	352	stream->wait_fd, stream->key);
	353
	354	/* We can consume the 1 byte written into the wait_fd by UST */
effcf122 MD	355	if (!stream->hangup_flush_done) {
	356	do {
	357	readlen = read(stream->wait_fd, &dummy, 1);
87dc6a9c	358	} while (readlen == -1 && errno == EINTR);
effcf122 MD	359	if (readlen == -1) {
	360	ret = readlen;
	361	goto end;
	362	}
d41f73b7 MD	363	}
	364
	365	buf = stream->buf;
	366	handle = stream->chan->handle;
	367	/* Get the next subbuffer */
	368	err = ustctl_get_next_subbuf(handle, buf);
	369	if (err != 0) {
effcf122	370	ret = -ret; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
d41f73b7 MD	371	/*
	372	* This is a debug message even for single-threaded consumer,
	373	* because poll() have more relaxed criterions than get subbuf,
	374	* so get_subbuf may fail for short race windows where poll()
	375	* would issue wakeups.
	376	*/
	377	DBG("Reserving sub buffer failed (everything is normal, "
	378	"it is due to concurrency)");
	379	goto end;
	380	}
	381	assert(stream->output == LTTNG_EVENT_MMAP);
	382	/* read the used subbuffer size */
	383	err = ustctl_get_padded_subbuf_size(handle, buf, &len);
effcf122	384	assert(err == 0);
d41f73b7 MD	385	/* write the subbuffer to the tracefile */
	386	ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
	387	if (ret < 0) {
	388	/*
	389	* display the error but continue processing to try
	390	* to release the subbuffer
	391	*/
	392	ERR("Error writing to tracefile");
	393	}
	394	err = ustctl_put_next_subbuf(handle, buf);
effcf122	395	assert(err == 0);
d41f73b7 MD	396	end:
	397	return ret;
	398	}
	399
	400	int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
	401	{
	402	int ret;
	403
	404	/* Opening the tracefile in write mode */
	405	if (stream->path_name != NULL) {
e11d277b	406	ret = run_as_open(stream->path_name,
60b6c79c MD	407	O_WRONLY\|O_CREAT\|O_TRUNC,
	408	S_IRWXU\|S_IRWXG\|S_IRWXO,
	409	stream->uid, stream->gid);
d41f73b7 MD	410	if (ret < 0) {
d41f73b7 MD	411	ERR("Opening %s", stream->path_name);
4c462e79	412	PERROR("open");
d41f73b7 MD	413	goto error;
	414	}
	415	stream->out_fd = ret;
	416	}
	417
	418	/* we return 0 to let the library handle the FD internally */
	419	return 0;
	420
	421	error:
	422	return ret;
	423	}