relayd: cleanup

[lttng-tools.git] / src / common / kernel-consumer / kernel-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/types.h>
#include <unistd.h>
#include <sys/stat.h>

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

#include "kernel-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
 */
ssize_t lttng_kconsumer_on_read_subbuffer_mmap(
		struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream, unsigned long len)
{
	unsigned long mmap_offset;
	ssize_t ret = 0, written = 0;
	off_t orig_offset = stream->out_fd_offset;
	int fd = stream->wait_fd;
	/* Default is on the disk */
	int outfd = stream->out_fd;
	uint64_t metadata_id;
	struct consumer_relayd_sock_pair *relayd = NULL;

	/* Flag that the current stream if set for network streaming. */
	if (stream->net_seq_idx != -1) {
		relayd = consumer_find_relayd(stream->net_seq_idx);
		if (relayd == NULL) {
			goto end;
		}
	}

	/* get the offset inside the fd to mmap */
	ret = kernctl_get_mmap_read_offset(fd, &mmap_offset);
	if (ret != 0) {
		errno = -ret;
		perror("kernctl_get_mmap_read_offset");
		written = ret;
		goto end;
	}

	/* RCU lock for the relayd pointer */
	rcu_read_lock();

	/* Handle stream on the relayd if the output is on the network */
	if (relayd) {
		/*
		 * Lock the control socket for the complete duration of the function
		 * since from this point on we will use the socket.
		 */
		if (stream->metadata_flag) {
			/* Metadata requires the control socket. */
			pthread_mutex_lock(&relayd->ctrl_sock_mutex);
		}

		ret = consumer_handle_stream_before_relayd(stream, len);
		if (ret >= 0) {
			/* Use the returned socket. */
			outfd = ret;

			/* Write metadata stream id before payload */
			if (stream->metadata_flag) {
				metadata_id = htobe64(stream->relayd_stream_id);
				do {
					ret = write(outfd, (void *) &metadata_id,
							sizeof(stream->relayd_stream_id));
					if (ret < 0) {
						PERROR("write metadata stream id");
						written = ret;
						goto end;
					}
				} while (errno == EINTR);
				DBG("Metadata stream id %zu written before data",
						stream->relayd_stream_id);
				/*
				 * We do this so the return value can match the len passed as
				 * argument to this function.
				 */
				written -= sizeof(stream->relayd_stream_id);
			}
		}
		/* Else, use the default set before which is the filesystem. */
	}

	while (len > 0) {
		ret = write(outfd, stream->mmap_base + mmap_offset, len);
		if (ret < 0) {
			if (errno == EINTR) {
				/* restart the interrupted system call */
				continue;
			} else {
				perror("Error in file write");
				if (written == 0) {
					written = ret;
				}
				goto end;
			}
		} else if (ret > len) {
			perror("Error in file write");
			written += ret;
			goto end;
		} else {
			len -= ret;
			mmap_offset += ret;
		}

		/* This call is useless on a socket so better save a syscall. */
		if (!relayd) {
			/* 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;
		}
		written += ret;
	}
	lttng_consumer_sync_trace_file(stream, orig_offset);

end:
	/* Unlock only if ctrl socket used */
	if (relayd && stream->metadata_flag) {
		pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
	}

	rcu_read_unlock();

	return written;
}

/*
 * Splice the data from the ring buffer to the tracefile.
 *
 * Returns the number of bytes spliced.
 */
ssize_t lttng_kconsumer_on_read_subbuffer_splice(
		struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream, unsigned long len)
{
	ssize_t ret = 0, written = 0, ret_splice = 0;
	loff_t offset = 0;
	off_t orig_offset = stream->out_fd_offset;
	int fd = stream->wait_fd;
	/* Default is on the disk */
	int outfd = stream->out_fd;
	uint64_t metadata_id;
	struct consumer_relayd_sock_pair *relayd = NULL;

	/* Flag that the current stream if set for network streaming. */
	if (stream->net_seq_idx != -1) {
		relayd = consumer_find_relayd(stream->net_seq_idx);
		if (relayd == NULL) {
			goto end;
		}
	}

	/* RCU lock for the relayd pointer */
	rcu_read_lock();

	/* Write metadata stream id before payload */
	if (stream->metadata_flag && relayd) {
		/*
		 * Lock the control socket for the complete duration of the function
		 * since from this point on we will use the socket.
		 */
		pthread_mutex_lock(&relayd->ctrl_sock_mutex);

		do {
			metadata_id = htobe64(stream->relayd_stream_id);
			ret = write(ctx->consumer_thread_pipe[1],
					(void *) &metadata_id,
					sizeof(stream->relayd_stream_id));
			if (ret < 0) {
				PERROR("write metadata stream id");
				written = ret;
				goto end;
			}
		} while (errno == EINTR);
		DBG("Metadata stream id %zu written before data",
				stream->relayd_stream_id);
	}

	while (len > 0) {
		DBG("splice chan to pipe offset %lu of len %lu (fd : %d)",
				(unsigned long)offset, len, fd);
		ret_splice = splice(fd, &offset, ctx->consumer_thread_pipe[1], NULL, len,
				SPLICE_F_MOVE | SPLICE_F_MORE);
		DBG("splice chan to pipe, ret %zd", ret_splice);
		if (ret_splice < 0) {
			perror("Error in relay splice");
			if (written == 0) {
				written = ret_splice;
			}
			ret = errno;
			goto splice_error;
		}

		/* Handle stream on the relayd if the output is on the network */
		if (relayd) {
			if (stream->metadata_flag) {
				/* Update counter to fit the spliced data */
				ret_splice += sizeof(stream->relayd_stream_id);
				len += sizeof(stream->relayd_stream_id);
				/*
				 * We do this so the return value can match the len passed as
				 * argument to this function.
				 */
				written -= sizeof(stream->relayd_stream_id);
			}

			ret = consumer_handle_stream_before_relayd(stream, ret_splice);
			if (ret >= 0) {
				/* Use the returned socket. */
				outfd = ret;
			} else {
				if (outfd == -1) {
					ERR("Remote relayd disconnected. Stopping");
					goto end;
				}
			}
		}

		DBG3("Kernel consumer splice data in %d to out %d",
				ctx->consumer_thread_pipe[0], outfd);
		ret_splice = splice(ctx->consumer_thread_pipe[0], NULL, outfd, NULL,
				ret_splice, SPLICE_F_MOVE | SPLICE_F_MORE);
		DBG("splice pipe to file, ret %zd", ret_splice);
		if (ret_splice < 0) {
			perror("Error in file splice");
			if (written == 0) {
				written = ret_splice;
			}
			ret = errno;
			goto splice_error;
		}
		if (ret_splice > len) {
			errno = EINVAL;
			PERROR("Wrote more data than requested %zd (len: %lu)",
					ret_splice, len);
			written += ret_splice;
			ret = errno;
			goto splice_error;
		}
		len -= ret_splice;

		/* This call is useless on a socket so better save a syscall. */
		if (!relayd) {
			/* This won't block, but will start writeout asynchronously */
			lttng_sync_file_range(outfd, stream->out_fd_offset, ret_splice,
					SYNC_FILE_RANGE_WRITE);
			stream->out_fd_offset += ret_splice;
		}
		written += ret_splice;
	}
	lttng_consumer_sync_trace_file(stream, orig_offset);

	ret = ret_splice;

	goto end;

splice_error:
	/* send the appropriate error description to sessiond */
	switch (ret) {
	case EBADF:
		lttng_consumer_send_error(ctx, CONSUMERD_SPLICE_EBADF);
		break;
	case EINVAL:
		lttng_consumer_send_error(ctx, CONSUMERD_SPLICE_EINVAL);
		break;
	case ENOMEM:
		lttng_consumer_send_error(ctx, CONSUMERD_SPLICE_ENOMEM);
		break;
	case ESPIPE:
		lttng_consumer_send_error(ctx, CONSUMERD_SPLICE_ESPIPE);
		break;
	}

end:
	if (relayd && stream->metadata_flag) {
		pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
	}

	rcu_read_unlock();

	return written;
}

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

	ret = kernctl_snapshot(infd);
	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_kconsumer_get_produced_snapshot(
		struct lttng_consumer_local_data *ctx,
		struct lttng_consumer_stream *stream,
		unsigned long *pos)
{
	int ret;
	int infd = stream->wait_fd;

	ret = kernctl_snapshot_get_produced(infd, pos);
	if (ret != 0) {
		errno = -ret;
		perror("kernctl_snapshot_get_produced");
	}

	return ret;
}

int lttng_kconsumer_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_CMD);
		return ret;
	}
	if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
		return -ENOENT;
	}

	switch (msg.cmd_type) {
	case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
	{
		int fd;
		struct consumer_relayd_sock_pair *relayd;

		DBG("Consumer adding relayd socket");

		/* Get relayd reference if exists. */
		relayd = consumer_find_relayd(msg.u.relayd_sock.net_index);
		if (relayd == NULL) {
			/* Not found. Allocate one. */
			relayd = consumer_allocate_relayd_sock_pair(
					msg.u.relayd_sock.net_index);
			if (relayd == NULL) {
				lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
				goto end_nosignal;
			}
		}

		/* Poll on consumer socket. */
		if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
			return -EINTR;
		}

		/* Get relayd socket from session daemon */
		ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
		if (ret != sizeof(fd)) {
			lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
			goto end_nosignal;
		}

		/* Copy socket information and received FD */
		switch (msg.u.relayd_sock.type) {
		case LTTNG_STREAM_CONTROL:
			/* Copy received lttcomm socket */
			lttcomm_copy_sock(&relayd->control_sock, &msg.u.relayd_sock.sock);

			ret = lttcomm_create_sock(&relayd->control_sock);
			if (ret < 0) {
				goto end_nosignal;
			}

			/* Close the created socket fd which is useless */
			close(relayd->control_sock.fd);

			/* Assign new file descriptor */
			relayd->control_sock.fd = fd;
			break;
		case LTTNG_STREAM_DATA:
			/* Copy received lttcomm socket */
			lttcomm_copy_sock(&relayd->data_sock, &msg.u.relayd_sock.sock);
			ret = lttcomm_create_sock(&relayd->data_sock);
			if (ret < 0) {
				goto end_nosignal;
			}

			/* Close the created socket fd which is useless */
			close(relayd->data_sock.fd);

			/* Assign new file descriptor */
			relayd->data_sock.fd = fd;
			break;
		default:
			ERR("Unknown relayd socket type");
			goto end_nosignal;
		}

		DBG("Consumer %s socket created successfully with net idx %d (fd: %d)",
				msg.u.relayd_sock.type == LTTNG_STREAM_CONTROL ? "control" : "data",
				relayd->net_seq_idx, fd);

		/*
		 * Add relayd socket pair to consumer data hashtable. If object already
		 * exists or on error, the function gracefully returns.
		 */
		consumer_add_relayd(relayd);

		goto end_nosignal;
	}
	case LTTNG_CONSUMER_ADD_CHANNEL:
	{
		struct lttng_consumer_channel *new_channel;

		DBG("consumer_add_channel %d", msg.u.channel.channel_key);
		new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
				-1, -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:
	{
		int fd;
		struct consumer_relayd_sock_pair *relayd = NULL;
		struct lttng_consumer_stream *new_stream;

		/* block */
		if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
			return -EINTR;
		}

		/* Get stream file descriptor from socket */
		ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
		if (ret != sizeof(fd)) {
			lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
			return ret;
		}

		new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
				msg.u.stream.stream_key,
				fd, fd,
				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,
				msg.u.stream.net_index,
				msg.u.stream.metadata_flag);
		if (new_stream == NULL) {
			lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
			goto end;
		}

		/* The stream is not metadata. Get relayd reference if exists. */
		relayd = consumer_find_relayd(msg.u.stream.net_index);
		if (relayd != NULL) {
			/* Add stream on the relayd */
			pthread_mutex_lock(&relayd->ctrl_sock_mutex);
			ret = relayd_add_stream(&relayd->control_sock,
					msg.u.stream.name, msg.u.stream.path_name,
					&new_stream->relayd_stream_id);
			pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
			if (ret < 0) {
				goto end;
			}
		} else if (msg.u.stream.net_index != -1) {
			ERR("Network sequence index %d unknown. Not adding stream.",
					msg.u.stream.net_index);
			free(new_stream);
			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);
		}

		DBG("Kernel consumer_add_stream (%d)", fd);
		break;
	}
	case LTTNG_CONSUMER_UPDATE_STREAM:
	{
		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);
		}
		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;
}

/*
 * Consume data on a file descriptor and write it on a trace file.
 */
ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
		struct lttng_consumer_local_data *ctx)
{
	unsigned long len;
	int err;
	ssize_t ret = 0;
	int infd = stream->wait_fd;

	DBG("In read_subbuffer (infd : %d)", infd);
	/* Get the next subbuffer */
	err = kernctl_get_next_subbuf(infd);
	if (err != 0) {
		/*
		 * 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;
	}

	switch (stream->output) {
		case LTTNG_EVENT_SPLICE:
			/* read the whole subbuffer */
			err = kernctl_get_padded_subbuf_size(infd, &len);
			if (err != 0) {
				errno = -ret;
				perror("Getting sub-buffer len failed.");
				goto end;
			}

			/* splice the subbuffer to the tracefile */
			ret = lttng_consumer_on_read_subbuffer_splice(ctx, stream, len);
			if (ret != len) {
				/*
				 * display the error but continue processing to try
				 * to release the subbuffer
				 */
				ERR("Error splicing to tracefile (ret: %ld != len: %ld)",
						ret, len);
			}

			break;
		case LTTNG_EVENT_MMAP:
			/* read the used subbuffer size */
			err = kernctl_get_padded_subbuf_size(infd, &len);
			if (err != 0) {
				errno = -ret;
				perror("Getting sub-buffer len failed.");
				goto end;
			}
			/* write the subbuffer to the tracefile */
			ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
			if (ret != len) {
				/*
				 * display the error but continue processing to try
				 * to release the subbuffer
				 */
				ERR("Error writing to tracefile");
			}
			break;
		default:
			ERR("Unknown output method");
			ret = -1;
	}

	err = kernctl_put_next_subbuf(infd);
	if (err != 0) {
		errno = -ret;
		if (errno == EFAULT) {
			perror("Error in unreserving sub buffer\n");
		} else if (errno == EIO) {
			/* Should never happen with newer LTTng versions */
			perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
		}
		goto end;
	}

end:
	return ret;
}

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

	/* Opening the tracefile in write mode */
	if (strlen(stream->path_name) > 0 && stream->net_seq_idx == -1) {
		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;
	}

	if (stream->output == LTTNG_EVENT_MMAP) {
		/* get the len of the mmap region */
		unsigned long mmap_len;

		ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
		if (ret != 0) {
			errno = -ret;
			perror("kernctl_get_mmap_len");
			goto error_close_fd;
		}
		stream->mmap_len = (size_t) mmap_len;

		stream->mmap_base = mmap(NULL, stream->mmap_len,
				PROT_READ, MAP_PRIVATE, stream->wait_fd, 0);
		if (stream->mmap_base == MAP_FAILED) {
			perror("Error mmaping");
			ret = -1;
			goto error_close_fd;
		}
	}

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

error_close_fd:
	{
		int err;

		err = close(stream->out_fd);
		assert(!err);
	}
error:
	return ret;
}