X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=lttd%2Flttd.c;h=9422a1f499cd37149156d56a1b50e6da5477a9d6;hb=HEAD;hp=773cb234108350df3ac15ef1b5f1e4e7e5f97c22;hpb=572db7d9168063ea3301de2e996cf329ff5d147f;p=ltt-control.git

diff --git a/lttd/lttd.c b/lttd/lttd.c
index 773cb23..9422a1f 100644
--- a/lttd/lttd.c
+++ b/lttd/lttd.c
@@ -1,14 +1,30 @@
-/* lttd
+/*
+ * lttd
  *
  * Linux Trace Toolkit Daemon
  *
- * This is a simple daemon that reads a few relay+debugfs channels and save
- * them in a trace.
+ * This is a simple daemon that reads a few LTTng debugfs channels and saves
+ * them in a trace on the virtual file system.
  *
  * CPU hot-plugging is supported using inotify.
  *
- * Copyright 2005 -
- * 	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ * Copyright 2009-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright 2010 - Michael Sills-Lavoie <michael.sills-lavoie@polymtl.ca>
+ * Copyright 2010 - Oumarou Dicko <oumarou.dicko@polymtl.ca>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
  */
 
 #ifdef HAVE_CONFIG_H
@@ -17,130 +33,26 @@
 
 #define _REENTRANT
 #define _GNU_SOURCE
-#include <features.h>
+
 #include <stdio.h>
-#include <unistd.h>
-#include <errno.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <stdlib.h>
-#include <dirent.h>
-#include <string.h>
-#include <fcntl.h>
-#include <sys/poll.h>
-#include <sys/mman.h>
 #include <signal.h>
-#include <pthread.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-#include <asm/ioctls.h>
-
-#include <linux/version.h>
-
-/* Relayfs IOCTL */
-#include <asm/ioctl.h>
-#include <asm/types.h>
-
-/* Get the next sub buffer that can be read. */
-#define RELAY_GET_SB		_IOR(0xF5, 0x00,__u32)
-/* Release the oldest reserved (by "get") sub buffer. */
-#define RELAY_PUT_SB		_IOW(0xF5, 0x01,__u32)
-/* returns the number of sub buffers in the per cpu channel. */
-#define RELAY_GET_N_SB		_IOR(0xF5, 0x02,__u32)
-/* returns the size of the current sub buffer. */
-#define RELAY_GET_SB_SIZE	_IOR(0xF5, 0x03, __u32)
-/* returns the size of data to consume in the current sub-buffer. */
-#define RELAY_GET_MAX_SB_SIZE	_IOR(0xF5, 0x04, __u32)
-
-
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,14)
-#include <sys/inotify.h>
-#if 0	/* should now be provided by libc. */
-/* From the inotify-tools 2.6 package */
-static inline int inotify_init (void)
-{
-	return syscall (__NR_inotify_init);
-}
-
-static inline int inotify_add_watch (int fd, const char *name, __u32 mask)
-{
-	return syscall (__NR_inotify_add_watch, fd, name, mask);
-}
-
-static inline int inotify_rm_watch (int fd, __u32 wd)
-{
-	return syscall (__NR_inotify_rm_watch, fd, wd);
-}
-#endif //0
-#define HAS_INOTIFY
-#else
-static inline int inotify_init (void)
-{
-	return -1;
-}
-
-static inline int inotify_add_watch (int fd, const char *name, __u32 mask)
-{
-	return 0;
-}
-
-static inline int inotify_rm_watch (int fd, __u32 wd)
-{
-	return 0;
-}
-#undef HAS_INOTIFY
-#endif
-
-struct fd_pair {
-	int channel;
-	int trace;
-	unsigned int n_sb;
-	unsigned int max_sb_size;
-	void *mmap;
-	pthread_mutex_t	mutex;
-};
-
-struct channel_trace_fd {
-	struct fd_pair *pair;
-	int num_pairs;
-};
-
-struct inotify_watch {
-	int wd;
-	char path_channel[PATH_MAX];
-	char path_trace[PATH_MAX];
-};
-
-struct inotify_watch_array {
-	struct inotify_watch *elem;
-	int num;
-};
-
-static __thread int thread_pipe[2];
-
-struct channel_trace_fd fd_pairs = { NULL, 0 };
-int inotify_fd = -1;
-struct inotify_watch_array inotify_watch_array = { NULL, 0 };
+#include <errno.h>
 
-/* protects fd_pairs and inotify_watch_array */
-pthread_rwlock_t fd_pairs_lock = PTHREAD_RWLOCK_INITIALIZER;
+#include <liblttd/liblttd.h>
+#include <liblttd/liblttdvfs.h>
 
+struct liblttd_instance* instance;
 
 static char		*trace_name = NULL;
 static char		*channel_name = NULL;
 static int		daemon_mode = 0;
 static int		append_mode = 0;
 static unsigned long	num_threads = 1;
-volatile static int	quit_program = 0;	/* For signal handler */
 static int		dump_flight_only = 0;
 static int		dump_normal_only = 0;
 static int		verbose_mode = 0;
 
-#define printf_verbose(fmt, args...) \
-  do {                               \
-    if (verbose_mode)                \
-      printf(fmt, ##args);           \
-  } while (0)
 
 /* Args :
  *
@@ -178,7 +90,7 @@ int parse_arguments(int argc, char **argv)
 {
 	int ret = 0;
 	int argn = 1;
-	
+
 	if(argc == 2) {
 		if(strcmp(argv[1], "-h") == 0) {
 			return 1;
@@ -236,19 +148,19 @@ int parse_arguments(int argc, char **argv)
 		}
 		argn++;
 	}
-	
+
 	if(trace_name == NULL) {
 		printf("Please specify a trace name.\n");
 		printf("\n");
 		ret = -1;
 	}
-	
+
 	if(channel_name == NULL) {
 		printf("Please specify a channel name.\n");
 		printf("\n");
 		ret = -1;
 	}
-	
+
 	return ret;
 }
 
@@ -267,703 +179,14 @@ void show_info(void)
 static void handler(int signo)
 {
 	printf("Signal %d received : exiting cleanly\n", signo);
-	quit_program = 1;
-}
-
-
-int open_buffer_file(char *filename, char *path_channel, char *path_trace,
-	struct channel_trace_fd *fd_pairs)
-{
-	int open_ret = 0;
-	int ret = 0;
-	struct stat stat_buf;
-
-	if(strncmp(filename, "flight-", sizeof("flight-")-1) != 0) {
-		if(dump_flight_only) {
-			printf_verbose("Skipping normal channel %s\n",
-				path_channel);
-			return 0;
-		}
-	} else {
-		if(dump_normal_only) {
-			printf_verbose("Skipping flight channel %s\n",
-				path_channel);
-			return 0;
-		}
-	}
-	printf_verbose("Opening file.\n");
-	
-	fd_pairs->pair = realloc(fd_pairs->pair,
-			++fd_pairs->num_pairs * sizeof(struct fd_pair));
-
-	/* Open the channel in read mode */
-	fd_pairs->pair[fd_pairs->num_pairs-1].channel = 
-		open(path_channel, O_RDONLY | O_NONBLOCK);
-	if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
-		perror(path_channel);
-		fd_pairs->num_pairs--;
-		return 0;	/* continue */
-	}
-	/* Open the trace in write mode, only append if append_mode */
-	ret = stat(path_trace, &stat_buf);
-	if(ret == 0) {
-		if(append_mode) {
-			printf_verbose("Appending to file %s as requested\n",
-				path_trace);
-
-			fd_pairs->pair[fd_pairs->num_pairs-1].trace = 
-				open(path_trace, O_WRONLY,
-						S_IRWXU|S_IRWXG|S_IRWXO);
-			if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
-				perror(path_trace);
-				open_ret = -1;
-				close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
-				fd_pairs->num_pairs--;
-				goto end;
-			}
-			ret = lseek(fd_pairs->pair[fd_pairs->num_pairs-1].trace,
-				    0, SEEK_END);
-			if (ret < 0) {
-				perror(path_trace);
-				open_ret = -1;
-				close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
-				close(fd_pairs->pair[fd_pairs->num_pairs-1].trace);
-				fd_pairs->num_pairs--;
-				goto end;
-			}
-		} else {
-			printf("File %s exists, cannot open. Try append mode.\n", path_trace);
-			open_ret = -1;
-			close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
-			fd_pairs->num_pairs--;
-			goto end;
-		}
-	} else {
-		if(errno == ENOENT) {
-			fd_pairs->pair[fd_pairs->num_pairs-1].trace = 
-				open(path_trace, O_WRONLY|O_CREAT|O_EXCL,
-						S_IRWXU|S_IRWXG|S_IRWXO);
-			if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
-				perror(path_trace);
-				open_ret = -1;
-				close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
-				fd_pairs->num_pairs--;
-				goto end;
-			}
-		}
-	}
-end:
-	return open_ret;
+	liblttd_stop_instance(instance);
 }
 
-int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
-		struct channel_trace_fd *fd_pairs, int *inotify_fd,
-		struct inotify_watch_array *iwatch_array)
-{
-	DIR *channel_dir = opendir(subchannel_name);
-	struct dirent *entry;
-	struct stat stat_buf;
-	int ret;
-	char path_channel[PATH_MAX];
-	int path_channel_len;
-	char *path_channel_ptr;
-	char path_trace[PATH_MAX];
-	int path_trace_len;
-	char *path_trace_ptr;
-	int open_ret = 0;
-
-	if(channel_dir == NULL) {
-		perror(subchannel_name);
-		open_ret = ENOENT;
-		goto end;
-	}
-
-	printf_verbose("Creating trace subdirectory %s\n", subtrace_name);
-	ret = mkdir(subtrace_name, S_IRWXU|S_IRWXG|S_IRWXO);
-	if(ret == -1) {
-		if(errno != EEXIST) {
-			perror(subtrace_name);
-			open_ret = -1;
-			goto end;
-		}
-	}
-
-	strncpy(path_channel, subchannel_name, PATH_MAX-1);
-	path_channel_len = strlen(path_channel);
-	path_channel[path_channel_len] = '/';
-	path_channel_len++;
-	path_channel_ptr = path_channel + path_channel_len;
-
-	strncpy(path_trace, subtrace_name, PATH_MAX-1);
-	path_trace_len = strlen(path_trace);
-	path_trace[path_trace_len] = '/';
-	path_trace_len++;
-	path_trace_ptr = path_trace + path_trace_len;
-	
-#ifdef HAS_INOTIFY
-	iwatch_array->elem = realloc(iwatch_array->elem,
-		++iwatch_array->num * sizeof(struct inotify_watch));
-	
-	printf_verbose("Adding inotify for channel %s\n", path_channel);
-	iwatch_array->elem[iwatch_array->num-1].wd = inotify_add_watch(*inotify_fd, path_channel, IN_CREATE);
-	strcpy(iwatch_array->elem[iwatch_array->num-1].path_channel, path_channel);
-	strcpy(iwatch_array->elem[iwatch_array->num-1].path_trace, path_trace);
-	printf_verbose("Added inotify for channel %s, wd %u\n",
-		iwatch_array->elem[iwatch_array->num-1].path_channel,
-		iwatch_array->elem[iwatch_array->num-1].wd);
-#endif
-
-	while((entry = readdir(channel_dir)) != NULL) {
-
-		if(entry->d_name[0] == '.') continue;
-		
-		strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
-		strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len);
-		
-		ret = stat(path_channel, &stat_buf);
-		if(ret == -1) {
-			perror(path_channel);
-			continue;
-		}
-		
-		printf_verbose("Channel file : %s\n", path_channel);
-		
-		if(S_ISDIR(stat_buf.st_mode)) {
-
-			printf_verbose("Entering channel subdirectory...\n");
-			ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs,
-				inotify_fd, iwatch_array);
-			if(ret < 0) continue;
-		} else if(S_ISREG(stat_buf.st_mode)) {
-			open_ret = open_buffer_file(entry->d_name, path_channel, path_trace,
-				fd_pairs);
-			if(open_ret)
-				goto end;
-		}
-	}
-	
-end:
-	closedir(channel_dir);
-
-	return open_ret;
-}
-
-
-int read_subbuffer(struct fd_pair *pair)
-{
-	unsigned int consumed_old, len;
-	int err;
-	long ret;
-	off_t offset;
-
-
-	err = ioctl(pair->channel, RELAY_GET_SB, &consumed_old);
-	printf_verbose("cookie : %u\n", consumed_old);
-	if(err != 0) {
-		ret = errno;
-		perror("Reserving sub buffer failed (everything is normal, it is due to concurrency)");
-		goto get_error;
-	}
-#if 0
-	err = TEMP_FAILURE_RETRY(write(pair->trace,
-				pair->mmap 
-					+ (consumed_old & ((pair->n_subbufs * pair->subbuf_size)-1)),
-				pair->subbuf_size));
-
-	if(err < 0) {
-		ret = errno;
-		perror("Error in writing to file");
-		goto write_error;
-	}
-#endif //0
-	err = ioctl(pair->channel, RELAY_GET_SB_SIZE, &len);
-	if(err != 0) {
-		ret = errno;
-		perror("Getting sub-buffer len failed.");
-		goto get_error;
-	}
-
-	offset = 0;
-	while (len > 0) {
-		printf_verbose("splice chan to pipe offset %lu\n",
-			(unsigned long)offset);
-		ret = splice(pair->channel, &offset, thread_pipe[1], NULL,
-			len, SPLICE_F_MOVE | SPLICE_F_MORE);
-		printf_verbose("splice chan to pipe ret %ld\n", ret);
-		if (ret < 0) {
-			perror("Error in relay splice");
-			goto write_error;
-		}
-		ret = splice(thread_pipe[0], NULL, pair->trace, NULL,
-			ret, SPLICE_F_MOVE | SPLICE_F_MORE);
-		printf_verbose("splice pipe to file %ld\n", ret);
-		if (ret < 0) {
-			perror("Error in file splice");
-			goto write_error;
-		}
-		len -= ret;
-	}
-
-#if 0
-	err = fsync(pair->trace);
-	if(err < 0) {
-		ret = errno;
-		perror("Error in writing to file");
-		goto write_error;
-	}
-#endif //0
-write_error:
-	ret = 0;
-	err = ioctl(pair->channel, RELAY_PUT_SB, &consumed_old);
-	if(err != 0) {
-		ret = errno;
-		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 get_error;
-	}
-
-get_error:
-	return ret;
-}
-
-
-int map_channels(struct channel_trace_fd *fd_pairs,
-	int idx_begin, int idx_end)
-{
-	int i,j;
-	int ret=0;
-
-	if(fd_pairs->num_pairs <= 0) {
-		printf("No channel to read\n");
-		goto end;
-	}
-	
-	/* Get the subbuf sizes and number */
-
-	for(i=idx_begin;i<idx_end;i++) {
-		struct fd_pair *pair = &fd_pairs->pair[i];
-
-		ret = ioctl(pair->channel, RELAY_GET_N_SB, &pair->n_sb);
-		if(ret != 0) {
-			perror("Error in getting the number of sub-buffers");
-			goto end;
-		}
-		ret = ioctl(pair->channel, RELAY_GET_MAX_SB_SIZE, 
-			    &pair->max_sb_size);
-		if(ret != 0) {
-			perror("Error in getting the max sub-buffer size");
-			goto end;
-		}
-		ret = pthread_mutex_init(&pair->mutex, NULL);	/* Fast mutex */
-		if(ret != 0) {
-			perror("Error in mutex init");
-			goto end;
-		}
-	}
-
-#if 0
-	/* Mmap each FD */
-	for(i=idx_begin;i<idx_end;i++) {
-		struct fd_pair *pair = &fd_pairs->pair[i];
-
-		pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs, PROT_READ,
-				MAP_SHARED, pair->channel, 0);
-		if(pair->mmap == MAP_FAILED) {
-			perror("Mmap error");
-			goto munmap;
-		}
-	}
-
-	goto end; /* success */
-
-	/* Error handling */
-	/* munmap only the successfully mmapped indexes */
-munmap:
-		/* Munmap each FD */
-	for(j=idx_begin;j<i;j++) {
-		struct fd_pair *pair = &fd_pairs->pair[j];
-		int err_ret;
-
-		err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
-		if(err_ret != 0) {
-			perror("Error in munmap");
-		}
-		ret |= err_ret;
-	}
-
-#endif //0
-end:
-	return ret;
-}
-
-int unmap_channels(struct channel_trace_fd *fd_pairs)
-{
-	int j;
-	int ret=0;
-
-	/* Munmap each FD */
-	for(j=0;j<fd_pairs->num_pairs;j++) {
-		struct fd_pair *pair = &fd_pairs->pair[j];
-		int err_ret;
-
-#if 0
-		err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
-		if(err_ret != 0) {
-			perror("Error in munmap");
-		}
-		ret |= err_ret;
-#endif //0
-		err_ret = pthread_mutex_destroy(&pair->mutex);
-		if(err_ret != 0) {
-			perror("Error in mutex destroy");
-		}
-		ret |= err_ret;
-	}
-
-	return ret;
-}
-
-#ifdef HAS_INOTIFY
-/* Inotify event arrived.
- *
- * Only support add file for now.
- */
-
-int read_inotify(int inotify_fd,
-	struct channel_trace_fd *fd_pairs,
-	struct inotify_watch_array *iwatch_array)
-{
-	char buf[sizeof(struct inotify_event) + PATH_MAX];
-	char path_channel[PATH_MAX];
-	char path_trace[PATH_MAX];
-	ssize_t len;
-	struct inotify_event *ievent;
-	size_t offset;
-	unsigned int i;
-	int ret;
-	int old_num;
-	
-	offset = 0;
-	len = read(inotify_fd, buf, sizeof(struct inotify_event) + PATH_MAX);
-	if(len < 0) {
-
-		if(errno == EAGAIN)
-			return 0;  /* another thread got the data before us */
-
-		printf("Error in read from inotify FD %s.\n", strerror(len));
-		return -1;
-	}
-	while(offset < len) {
-		ievent = (struct inotify_event *)&(buf[offset]);
-		for(i=0; i<iwatch_array->num; i++) {
-			if(iwatch_array->elem[i].wd == ievent->wd &&
-				ievent->mask == IN_CREATE) {
-				printf_verbose(
-					"inotify wd %u event mask : %u for %s%s\n",
-					ievent->wd, ievent->mask,
-					iwatch_array->elem[i].path_channel,
-					ievent->name);
-				old_num = fd_pairs->num_pairs;
-				strcpy(path_channel, iwatch_array->elem[i].path_channel);
-				strcat(path_channel, ievent->name);
-				strcpy(path_trace, iwatch_array->elem[i].path_trace);
-				strcat(path_trace, ievent->name);
-				if(ret = open_buffer_file(ievent->name, path_channel,
-					path_trace, fd_pairs)) {
-					printf("Error opening buffer file\n");
-					return -1;
-				}
-				if(ret = map_channels(fd_pairs, old_num, fd_pairs->num_pairs)) {
-					printf("Error mapping channel\n");
-					return -1;
-				}
-
-			}
-		}
-		offset += sizeof(*ievent) + ievent->len;
-	}
-}
-#endif //HAS_INOTIFY
-
-/* read_channels
- *
- * Thread worker.
- *
- * Read the debugfs channels and write them in the paired tracefiles.
- *
- * @fd_pairs : paired channels and trace files.
- *
- * returns 0 on success, -1 on error.
- *
- * Note that the high priority polled channels are consumed first. We then poll
- * again to see if these channels are still in priority. Only when no
- * high priority channel is left, we start reading low priority channels.
- *
- * Note that a channel is considered high priority when the buffer is almost
- * full.
- */
-
-int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
-	int inotify_fd, struct inotify_watch_array *iwatch_array)
-{
-	struct pollfd *pollfd = NULL;
-	int num_pollfd;
-	int i,j;
-	int num_rdy, num_hup;
-	int high_prio;
-	int ret = 0;
-	int inotify_fds;
-	unsigned int old_num;
-
-#ifdef HAS_INOTIFY
-	inotify_fds = 1;
-#else
-	inotify_fds = 0;
-#endif
-
-	pthread_rwlock_rdlock(&fd_pairs_lock);
-
-	/* Start polling the FD. Keep one fd for inotify */
-	pollfd = malloc((inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
-
-#ifdef HAS_INOTIFY
-	pollfd[0].fd = inotify_fd;
-	pollfd[0].events = POLLIN|POLLPRI;
-#endif
-
-	for(i=0;i<fd_pairs->num_pairs;i++) {
-		pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
-		pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
-	}
-	num_pollfd = inotify_fds + fd_pairs->num_pairs;
-
-
-	pthread_rwlock_unlock(&fd_pairs_lock);
-
-	while(1) {
-		high_prio = 0;
-		num_hup = 0; 
-#ifdef DEBUG
-		printf("Press a key for next poll...\n");
-		char buf[1];
-		read(STDIN_FILENO, &buf, 1);
-		printf("Next poll (polling %d fd) :\n", num_pollfd);
-#endif //DEBUG
-
-		/* Have we received a signal ? */
-		if(quit_program) break;
-		
-		num_rdy = poll(pollfd, num_pollfd, -1);
-
-		if(num_rdy == -1) {
-			perror("Poll error");
-			goto free_fd;
-		}
-
-		printf_verbose("Data received\n");
-#ifdef HAS_INOTIFY
-		switch(pollfd[0].revents) {
-			case POLLERR:
-				printf_verbose(
-					"Error returned in polling inotify fd %d.\n",
-					pollfd[0].fd);
-				break;
-			case POLLHUP:
-				printf_verbose(
-					"Polling inotify fd %d tells it has hung up.\n",
-					pollfd[0].fd);
-				break;
-			case POLLNVAL:
-				printf_verbose(
-					"Polling inotify fd %d tells fd is not open.\n",
-					pollfd[0].fd);
-				break;
-			case POLLPRI:
-			case POLLIN:
-				printf_verbose(
-					"Polling inotify fd %d : data ready.\n",
-					pollfd[0].fd);
-
-				pthread_rwlock_wrlock(&fd_pairs_lock);
-				read_inotify(inotify_fd, fd_pairs, iwatch_array);
-				pthread_rwlock_unlock(&fd_pairs_lock);
-
-			break;
-		}
-#endif
-
-		for(i=inotify_fds;i<num_pollfd;i++) {
-			switch(pollfd[i].revents) {
-				case POLLERR:
-					printf_verbose(
-						"Error returned in polling fd %d.\n",
-						pollfd[i].fd);
-					num_hup++;
-					break;
-				case POLLHUP:
-					printf_verbose(
-						"Polling fd %d tells it has hung up.\n",
-						pollfd[i].fd);
-					num_hup++;
-					break;
-				case POLLNVAL:
-					printf_verbose(
-						"Polling fd %d tells fd is not open.\n",
-						pollfd[i].fd);
-					num_hup++;
-					break;
-				case POLLPRI:
-					pthread_rwlock_rdlock(&fd_pairs_lock);
-					if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
-						printf_verbose(
-							"Urgent read on fd %d\n",
-							pollfd[i].fd);
-						/* Take care of high priority channels first. */
-						high_prio = 1;
-						/* it's ok to have an unavailable sub-buffer */
-						ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
-						if(ret == EAGAIN) ret = 0;
-
-						ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
-						if(ret)
-							printf("Error in mutex unlock : %s\n", strerror(ret));
-					}
-					pthread_rwlock_unlock(&fd_pairs_lock);
-					break;
-			}
-		}
-		/* If every buffer FD has hung up, we end the read loop here */
-		if(num_hup == num_pollfd - inotify_fds) break;
-
-		if(!high_prio) {
-			for(i=inotify_fds;i<num_pollfd;i++) {
-				switch(pollfd[i].revents) {
-					case POLLIN:
-						pthread_rwlock_rdlock(&fd_pairs_lock);
-						if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
-							/* Take care of low priority channels. */
-							printf_verbose(
-								"Normal read on fd %d\n",
-								pollfd[i].fd);
-							/* it's ok to have an unavailable subbuffer */
-							ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
-							if(ret == EAGAIN) ret = 0;
-
-							ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
-							if(ret)
-								printf("Error in mutex unlock : %s\n", strerror(ret));
-						}
-						pthread_rwlock_unlock(&fd_pairs_lock);
-						break;
-				}
-			}
-		}
-
-		/* Update pollfd array if an entry was added to fd_pairs */
-		pthread_rwlock_rdlock(&fd_pairs_lock);
-		if((inotify_fds + fd_pairs->num_pairs) != num_pollfd) {
-			pollfd = realloc(pollfd,
-					(inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
-			for(i=num_pollfd-inotify_fds;i<fd_pairs->num_pairs;i++) {
-				pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
-				pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
-			}
-			num_pollfd = fd_pairs->num_pairs + inotify_fds;
-		}
-		pthread_rwlock_unlock(&fd_pairs_lock);
-
-		/* NB: If the fd_pairs structure is updated by another thread from this
-		 *     point forward, the current thread will wait in the poll without
-		 *     monitoring the new channel. However, this thread will add the
-		 *     new channel on next poll (and this should not take too much time
-		 *     on a loaded system).
-		 *
-		 *     This event is quite unlikely and can only occur if a CPU is
-		 *     hot-plugged while multple lttd threads are running.
-		 */
-	}
-
-free_fd:
-	free(pollfd);
-
-end:
-	return ret;
-}
-
-
-void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs, int inotify_fd,
-	struct inotify_watch_array *iwatch_array)
-{
-	int i;
-	int ret;
-
-	for(i=0;i<fd_pairs->num_pairs;i++) {
-		ret = close(fd_pairs->pair[i].channel);
-		if(ret == -1) perror("Close error on channel");
-		ret = close(fd_pairs->pair[i].trace);
-		if(ret == -1) perror("Close error on trace");
-	}
-	free(fd_pairs->pair);
-	free(iwatch_array->elem);
-}
-
-/* Thread worker */
-void * thread_main(void *arg)
-{
-	long ret;
-	unsigned long thread_num = (unsigned long)arg;
-
-	ret = pipe(thread_pipe);
-	if (ret < 0) {
-		perror("Error creating pipe");
-		return (void*)ret;
-	}
-	ret = read_channels(thread_num, &fd_pairs, inotify_fd, &inotify_watch_array);
-	close(thread_pipe[0]);	/* close read end */
-	close(thread_pipe[1]);	/* close write end */
-	return (void*)ret;
-}
-
-
-int channels_init()
-{
-	int ret = 0;
-
-	inotify_fd = inotify_init();
-	fcntl(inotify_fd, F_SETFL, O_NONBLOCK);
-
-	if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs,
-			&inotify_fd, &inotify_watch_array))
-		goto close_channel;
-	if (fd_pairs.num_pairs == 0) {
-		printf("No channel available for reading, exiting\n");
-		ret = -ENOENT;
-		goto close_channel;
-	}
-	if(ret = map_channels(&fd_pairs, 0, fd_pairs.num_pairs))
-		goto close_channel;
-	return 0;
-
-close_channel:
-	close_channel_trace_pairs(&fd_pairs, inotify_fd, &inotify_watch_array);
-	if(inotify_fd >= 0)
-		close(inotify_fd);
-	return ret;
-}
-
-
 int main(int argc, char ** argv)
 {
 	int ret = 0;
 	struct sigaction act;
-	pthread_t *tids;
-	unsigned long i;
-	void *tret;
-	
+
 	ret = parse_arguments(argc, argv);
 
 	if(ret != 0) show_arguments();
@@ -983,9 +206,6 @@ int main(int argc, char ** argv)
 	sigaction(SIGQUIT, &act, NULL);
 	sigaction(SIGINT, &act, NULL);
 
-	if(ret = channels_init())
-		return ret;
-
 	if(daemon_mode) {
 		ret = daemon(0, 0);
 
@@ -995,33 +215,20 @@ int main(int argc, char ** argv)
 		}
 	}
 
-	tids = malloc(sizeof(pthread_t) * num_threads);
-	for(i=0; i<num_threads; i++) {
+	struct liblttd_callbacks* callbacks =
+		liblttdvfs_new_callbacks(trace_name, append_mode, verbose_mode);
 
-		ret = pthread_create(&tids[i], NULL, thread_main, (void*)i);
-		if(ret) {
-			perror("Error creating thread");
-			break;
-		}
-	}
+	instance = liblttd_new_instance(callbacks, channel_name, num_threads,
+					dump_flight_only, dump_normal_only,
+					verbose_mode);
 
-	for(i=0; i<num_threads; i++) {
-		ret = pthread_join(tids[i], &tret);
-		if(ret) {
-			perror("Error joining thread");
-			break;
-		}
-		if((long)tret != 0) {
-			printf("Error %s occured in thread %u\n",
-				strerror((long)tret), i);
-		}
+	if(!instance) {
+		perror("An error occured while creating the liblttd instance");
+		return ret;
 	}
 
-	free(tids);
-	ret = unmap_channels(&fd_pairs);
-	close_channel_trace_pairs(&fd_pairs, inotify_fd, &inotify_watch_array);
-	if(inotify_fd >= 0)
-		close(inotify_fd);
-			
+	liblttd_start_instance(instance);
+
 	return ret;
 }
+