[ltt-control.git] / ltt / branches / poly / lttd / lttd.c

/* lttd
 *
 * Linux Trace Toolkit Daemon
 *
 * This is a simple daemon that reads a few relayfs channels and save them in a
 * trace.
 *
 *
 * Copyright 2005 -
 * 	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
 */

#define _GNU_SOURCE
#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>

/* Relayfs IOCTL */
#include <asm/ioctl.h>
#include <asm/types.h>

/* Get the next sub buffer that can be read. */
#define RELAYFS_GET_SUBBUF        _IOR(0xF4, 0x00,__u32)
/* Release the oldest reserved (by "get") sub buffer. */
#define RELAYFS_PUT_SUBBUF        _IO(0xF4, 0x01)
/* returns the number of sub buffers in the per cpu channel. */
#define RELAYFS_GET_N_SUBBUFS     _IOR(0xF4, 0x02,__u32)
/* returns the size of the sub buffers. */
#define RELAYFS_GET_SUBBUF_SIZE   _IOR(0xF4, 0x03,__u32)


enum {
	GET_SUBBUF,
	PUT_SUBBUF,
	GET_N_BUBBUFS,
	GET_SUBBUF_SIZE
};

struct fd_pair {
	int channel;
	int trace;
	unsigned int n_subbufs;
	unsigned int subbuf_size;
	void *mmap;
};

struct channel_trace_fd {
	struct fd_pair *pair;
	int num_pairs;
};

static char *trace_name = NULL;
static char *channel_name = NULL;
static int	daemon_mode = 0;
static int	append_mode = 0;
volatile static int	quit_program = 0;	/* For signal handler */

/* Args :
 *
 * -t directory		Directory name of the trace to write to. Will be created.
 * -c directory		Root directory of the relayfs trace channels.
 * -d          		Run in background (daemon).
 * -a							Trace append mode.
 */
void show_arguments(void)
{
	printf("Please use the following arguments :\n");
	printf("\n");
	printf("-t directory  Directory name of the trace to write to.\n"
				 "              It will be created.\n");
	printf("-c directory  Root directory of the relayfs trace channels.\n");
	printf("-d            Run in background (daemon).\n");
	printf("-a            Append to an possibly existing trace.\n");
	printf("\n");
}


/* parse_arguments
 *
 * Parses the command line arguments.
 *
 * Returns 1 if the arguments were correct, but doesn't ask for program
 * continuation. Returns -1 if the arguments are incorrect, or 0 if OK.
 */
int parse_arguments(int argc, char **argv)
{
	int ret = 0;
	int argn = 1;
	
	if(argc == 2) {
		if(strcmp(argv[1], "-h") == 0) {
			return 1;
		}
	}

	while(argn < argc) {

		switch(argv[argn][0]) {
			case '-':
				switch(argv[argn][1]) {
					case 't':
						if(argn+1 < argc) {
							trace_name = argv[argn+1];
							argn++;
						}
						break;
					case 'c':
						if(argn+1 < argc) {
							channel_name = argv[argn+1];
							argn++;
						}
						break;
					case 'd':
						daemon_mode = 1;
						break;
					case 'a':
						append_mode = 1;
						break;
					default:
						printf("Invalid argument '%s'.\n", argv[argn]);
						printf("\n");
						ret = -1;
				}
				break;
			default:
				printf("Invalid argument '%s'.\n", argv[argn]);
				printf("\n");
				ret = -1;
		}
		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;
}

void show_info(void)
{
	printf("Linux Trace Toolkit Trace Daemon\n");
	printf("\n");
	printf("Reading from relayfs directory : %s\n", channel_name);
	printf("Writing to trace directory : %s\n", trace_name);
	printf("\n");
}


/* signal handling */

static void handler(int signo)
{
	printf("Signal %d received : exiting cleanly\n", signo);
	quit_program = 1;
}


int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
		struct channel_trace_fd *fd_pairs)
{
	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;

	if(channel_dir == NULL) {
		perror(subchannel_name);
		return ENOENT;
	}

	//FIXME : check if the directory already exist, and ask the user if he wants
	//to append to the traces.
	printf("Creating trace subdirectory %s\n", subtrace_name);
	ret = mkdir(subtrace_name, S_IRWXU|S_IRWXG|S_IRWXO);
	if(ret == -1) {
		if(errno == EEXIST && append_mode) {
			printf("Appending to directory %s as resquested\n", subtrace_name);
		} else {
			perror(subtrace_name);
			return -1;
		}
	}

	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;
	
	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("Channel file : %s\n", path_channel);
		
		if(S_ISDIR(stat_buf.st_mode)) {

			printf("Entering channel subdirectory...\n");
			ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs);
			if(ret < 0) continue;
		} else if(S_ISREG(stat_buf.st_mode)) {
			printf("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);
			}
			/* Open the trace in write mode, only append if append_mode */
			ret = stat(path_trace, &stat_buf);
			if(ret == 0) {
				if(append_mode) {
					printf("Appending to file %s as resquested\n", path_trace);

					fd_pairs->pair[fd_pairs->num_pairs-1].trace = 
						open(path_trace, O_WRONLY|O_APPEND,
								S_IRWXU|S_IRWXG|S_IRWXO);

					if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
						perror(path_trace);
					}
				} else {
					printf("File %s exists, cannot open. Try append mode.\n", path_trace);
					return -1;
				}
			} 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);
					}
				}
			}
		}
	}
	
	closedir(channel_dir);

	return 0;
}


int read_subbuffer(struct fd_pair *pair)
{
	unsigned int	subbuf_index;
	int ret;


	ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF, 
								&subbuf_index);
	if(ret != 0) {
		perror("Error in reserving sub buffer");
		goto error;
	}

	ret = TEMP_FAILURE_RETRY(write(pair->trace,
				pair->mmap + (subbuf_index * pair->subbuf_size),
				pair->subbuf_size));
	
	if(ret != 0) {
		perror("Error in writing to file");
		goto error;
	}


	ret = ioctl(pair->channel, RELAYFS_PUT_SUBBUF);
	if(ret != 0) {
		perror("Error in unreserving sub buffer");
		goto error;
	}

	return 0;
error:
	return -1;
}


/* read_channels
 *
 * Read the realyfs 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(struct channel_trace_fd *fd_pairs)
{
	struct pollfd *pollfd;
	int i,j;
	int num_rdy, num_hup;
	int high_prio;
	int ret;

	/* Get the subbuf sizes and number */

	for(i=0;i<fd_pairs->num_pairs;i++) {
		struct fd_pair *pair = &fd_pairs->pair[i];

		ret = ioctl(pair->channel, RELAYFS_GET_N_SUBBUFS, 
							&pair->n_subbufs);
		if(ret != 0) {
			perror("Error in getting the number of subbuffers");
			goto end;
		}
		ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF_SIZE, 
							&pair->subbuf_size);
		if(ret != 0) {
			perror("Error in getting the size of the subbuffers");
			goto end;
		}
	}

	/* Mmap each FD */
	for(i=0;i<fd_pairs->num_pairs;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;
		}
	}


	/* Start polling the FD */
	
	pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd));

	/* Note : index in pollfd is the same index as fd_pair->pair */
	for(i=0;i<fd_pairs->num_pairs;i++) {
		pollfd[i].fd = fd_pairs->pair[i].channel;
		pollfd[i].events = POLLIN|POLLPRI;
	}

	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 :\n");
#endif //DEBUG
		
		/* Have we received a signal ? */
		if(quit_program) break;
		
		num_rdy = poll(pollfd, fd_pairs->num_pairs, -1);
		if(num_rdy == -1) {
			perror("Poll error");
			goto free_fd;
		}

		printf("Data received\n");

		for(i=0;i<fd_pairs->num_pairs;i++) {
			switch(pollfd[i].revents) {
				case POLLERR:
					printf("Error returned in polling fd %d.\n", pollfd[i].fd);
					num_hup++;
					break;
				case POLLHUP:
					printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd);
					num_hup++;
					break;
				case POLLNVAL:
					printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd);
					num_hup++;
					break;
				case POLLPRI:
					printf("Urgent read on fd %d\n", pollfd[i].fd);
					/* Take care of high priority channels first. */
					high_prio = 1;
					ret |= read_subbuffer(&fd_pairs->pair[i]);
					break;
			}
		}
		/* If every FD has hung up, we end the read loop here */
		if(num_hup == fd_pairs->num_pairs) break;

		if(!high_prio) {
			for(i=0;i<fd_pairs->num_pairs;i++) {
				switch(pollfd[i].revents) {
					case POLLIN:
						/* Take care of low priority channels. */
						printf("Normal read on fd %d\n", pollfd[i].fd);
						ret |= read_subbuffer(&fd_pairs->pair[i]);
						break;
				}
			}
		}

	}

free_fd:
	free(pollfd);

	/* munmap only the successfully mmapped indexes */
	i = fd_pairs->num_pairs;
munmap:
		/* Munmap each FD */
	for(j=0;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;
	}

end:
	return ret;
}


void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs)
{
	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);
}

int main(int argc, char ** argv)
{
	int ret;
	pid_t pid;
	struct channel_trace_fd fd_pairs = { NULL, 0 };
	struct sigaction act;
	
	ret = parse_arguments(argc, argv);

	if(ret != 0) show_arguments();
	if(ret < 0) return EINVAL;
	if(ret > 0) return 0;

	show_info();

	if(daemon_mode) {
		pid = fork();
		
		if(pid > 0) {
			/* parent */
			return 0;
		} else if(pid < 0) {
			/* error */
			printf("An error occured while forking.\n");
			return -1;
		}
		/* else, we are the child, continue... */
	}

	/* Connect the signal handlers */
	act.sa_handler = handler;
	act.sa_flags = 0;
	sigemptyset(&(act.sa_mask));
	sigaddset(&(act.sa_mask), SIGTERM);
	sigaddset(&(act.sa_mask), SIGQUIT);
	sigaddset(&(act.sa_mask), SIGINT);
	sigaction(SIGTERM, &act, NULL);
	sigaction(SIGQUIT, &act, NULL);
	sigaction(SIGINT, &act, NULL);

	//return 0;
	if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs))
		goto close_channel;

	ret = read_channels(&fd_pairs);

close_channel:
	close_channel_trace_pairs(&fd_pairs);

	return ret;
}
Commit	Line	Data
617de8e1	1	/* lttd
	2	*
	3	* Linux Trace Toolkit Daemon
	4	*
	5	* This is a simple daemon that reads a few relayfs channels and save them in a
	6	* trace.
	7	*
	8	*
	9	* Copyright 2005 -
	10	* Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
	11	*/
	12
1d483eea	13	#define _GNU_SOURCE
617de8e1	14	#include <stdio.h>
1d483eea	15	#include <unistd.h>
617de8e1	16	#include <errno.h>
	17	#include <sys/types.h>
	18	#include <sys/stat.h>
617de8e1	19	#include <stdlib.h>
	20	#include <dirent.h>
	21	#include <string.h>
90ccaa9a	22	#include <fcntl.h>
90ccaa9a	23	#include <sys/poll.h>
1d483eea	24	#include <sys/mman.h>
	25	#include <signal.h>
	26
	27	/* Relayfs IOCTL */
	28	#include <asm/ioctl.h>
	29	#include <asm/types.h>
	30
	31	/* Get the next sub buffer that can be read. */
	32	#define RELAYFS_GET_SUBBUF _IOR(0xF4, 0x00,__u32)
	33	/* Release the oldest reserved (by "get") sub buffer. */
	34	#define RELAYFS_PUT_SUBBUF _IO(0xF4, 0x01)
	35	/* returns the number of sub buffers in the per cpu channel. */
	36	#define RELAYFS_GET_N_SUBBUFS _IOR(0xF4, 0x02,__u32)
	37	/* returns the size of the sub buffers. */
	38	#define RELAYFS_GET_SUBBUF_SIZE _IOR(0xF4, 0x03,__u32)
	39
	40
617de8e1	41
	42	enum {
	43	GET_SUBBUF,
	44	PUT_SUBBUF,
	45	GET_N_BUBBUFS,
	46	GET_SUBBUF_SIZE
	47	};
	48
	49	struct fd_pair {
	50	int channel;
	51	int trace;
1d483eea	52	unsigned int n_subbufs;
	53	unsigned int subbuf_size;
	54	void *mmap;
617de8e1	55	};
	56
	57	struct channel_trace_fd {
	58	struct fd_pair *pair;
	59	int num_pairs;
	60	};
	61
	62	static char *trace_name = NULL;
	63	static char *channel_name = NULL;
	64	static int daemon_mode = 0;
90ccaa9a	65	static int append_mode = 0;
1d483eea	66	volatile static int quit_program = 0; /* For signal handler */
617de8e1	67
	68	/* Args :
	69	*
	70	* -t directory Directory name of the trace to write to. Will be created.
	71	* -c directory Root directory of the relayfs trace channels.
	72	* -d Run in background (daemon).
90ccaa9a	73	* -a Trace append mode.
617de8e1	74	*/
	75	void show_arguments(void)
	76	{
	77	printf("Please use the following arguments :\n");
	78	printf("\n");
	79	printf("-t directory Directory name of the trace to write to.\n"
	80	" It will be created.\n");
	81	printf("-c directory Root directory of the relayfs trace channels.\n");
	82	printf("-d Run in background (daemon).\n");
90ccaa9a	83	printf("-a Append to an possibly existing trace.\n");
617de8e1	84	printf("\n");
	85	}
	86
	87
	88	/* parse_arguments
	89	*
	90	* Parses the command line arguments.
	91	*
	92	* Returns 1 if the arguments were correct, but doesn't ask for program
	93	* continuation. Returns -1 if the arguments are incorrect, or 0 if OK.
	94	*/
	95	int parse_arguments(int argc, char **argv)
	96	{
	97	int ret = 0;
	98	int argn = 1;
	99
	100	if(argc == 2) {
	101	if(strcmp(argv[1], "-h") == 0) {
	102	return 1;
	103	}
	104	}
	105
90ccaa9a	106	while(argn < argc) {
617de8e1	107
	108	switch(argv[argn][0]) {
	109	case '-':
	110	switch(argv[argn][1]) {
	111	case 't':
90ccaa9a	112	if(argn+1 < argc) {
	113	trace_name = argv[argn+1];
	114	argn++;
	115	}
617de8e1	116	break;
617de8e1	117	case 'c':
90ccaa9a	118	if(argn+1 < argc) {
	119	channel_name = argv[argn+1];
	120	argn++;
	121	}
617de8e1	122	break;
	123	case 'd':
	124	daemon_mode = 1;
	125	break;
90ccaa9a	126	case 'a':
	127	append_mode = 1;
	128	break;
617de8e1	129	default:
	130	printf("Invalid argument '%s'.\n", argv[argn]);
	131	printf("\n");
	132	ret = -1;
	133	}
	134	break;
	135	default:
	136	printf("Invalid argument '%s'.\n", argv[argn]);
	137	printf("\n");
	138	ret = -1;
	139	}
	140	argn++;
	141	}
	142
	143	if(trace_name == NULL) {
	144	printf("Please specify a trace name.\n");
	145	printf("\n");
	146	ret = -1;
	147	}
	148
	149	if(channel_name == NULL) {
	150	printf("Please specify a channel name.\n");
	151	printf("\n");
	152	ret = -1;
	153	}
	154
	155	return ret;
	156	}
	157
	158	void show_info(void)
	159	{
	160	printf("Linux Trace Toolkit Trace Daemon\n");
	161	printf("\n");
	162	printf("Reading from relayfs directory : %s\n", channel_name);
	163	printf("Writing to trace directory : %s\n", trace_name);
	164	printf("\n");
	165	}
	166
	167
1d483eea	168	/* signal handling */
	169
	170	static void handler(int signo)
	171	{
	172	printf("Signal %d received : exiting cleanly\n", signo);
	173	quit_program = 1;
	174	}
	175
	176
	177
617de8e1	178	int open_channel_trace_pairs(char subchannel_name, char subtrace_name,
	179	struct channel_trace_fd *fd_pairs)
	180	{
	181	DIR *channel_dir = opendir(subchannel_name);
	182	struct dirent *entry;
	183	struct stat stat_buf;
	184	int ret;
	185	char path_channel[PATH_MAX];
	186	int path_channel_len;
	187	char *path_channel_ptr;
	188	char path_trace[PATH_MAX];
	189	int path_trace_len;
	190	char *path_trace_ptr;
	191
	192	if(channel_dir == NULL) {
	193	perror(subchannel_name);
	194	return ENOENT;
	195	}
	196
	197	//FIXME : check if the directory already exist, and ask the user if he wants
	198	//to append to the traces.
	199	printf("Creating trace subdirectory %s\n", subtrace_name);
	200	ret = mkdir(subtrace_name, S_IRWXU\|S_IRWXG\|S_IRWXO);
	201	if(ret == -1) {
90ccaa9a	202	if(errno == EEXIST && append_mode) {
	203	printf("Appending to directory %s as resquested\n", subtrace_name);
	204	} else {
	205	perror(subtrace_name);
	206	return -1;
	207	}
617de8e1	208	}
	209
	210	strncpy(path_channel, subchannel_name, PATH_MAX-1);
	211	path_channel_len = strlen(path_channel);
	212	path_channel[path_channel_len] = '/';
	213	path_channel_len++;
	214	path_channel_ptr = path_channel + path_channel_len;
	215
	216	strncpy(path_trace, subtrace_name, PATH_MAX-1);
	217	path_trace_len = strlen(path_trace);
	218	path_trace[path_trace_len] = '/';
	219	path_trace_len++;
	220	path_trace_ptr = path_trace + path_trace_len;
	221
	222	while((entry = readdir(channel_dir)) != NULL) {
	223
	224	if(entry->d_name[0] == '.') continue;
	225
	226	strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
	227	strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len);
	228
	229	ret = stat(path_channel, &stat_buf);
	230	if(ret == -1) {
	231	perror(path_channel);
	232	continue;
	233	}
	234
	235	printf("Channel file : %s\n", path_channel);
	236
	237	if(S_ISDIR(stat_buf.st_mode)) {
	238
	239	printf("Entering channel subdirectory...\n");
	240	ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs);
	241	if(ret < 0) continue;
90ccaa9a	242	} else if(S_ISREG(stat_buf.st_mode)) {
	243	printf("Opening file.\n");
	244
	245	fd_pairs->pair = realloc(fd_pairs->pair,
	246	++fd_pairs->num_pairs * sizeof(struct fd_pair));
	247
	248	/* Open the channel in read mode */
	249	fd_pairs->pair[fd_pairs->num_pairs-1].channel =
	250	open(path_channel, O_RDONLY \| O_NONBLOCK);
	251	if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
	252	perror(path_channel);
	253	}
	254	/* Open the trace in write mode, only append if append_mode */
	255	ret = stat(path_trace, &stat_buf);
	256	if(ret == 0) {
	257	if(append_mode) {
	258	printf("Appending to file %s as resquested\n", path_trace);
	259
	260	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	261	open(path_trace, O_WRONLY\|O_APPEND,
	262	S_IRWXU\|S_IRWXG\|S_IRWXO);
	263
	264	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	265	perror(path_trace);
	266	}
	267	} else {
	268	printf("File %s exists, cannot open. Try append mode.\n", path_trace);
	269	return -1;
	270	}
	271	} else {
	272	if(errno == ENOENT) {
	273	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	274	open(path_trace, O_WRONLY\|O_CREAT\|O_EXCL,
	275	S_IRWXU\|S_IRWXG\|S_IRWXO);
	276	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	277	perror(path_trace);
	278	}
	279	}
	280	}
617de8e1	281	}
617de8e1	282	}
	283
	284	closedir(channel_dir);
	285
	286	return 0;
	287	}
	288
1d483eea	289
	290	int read_subbuffer(struct fd_pair *pair)
	291	{
	292	unsigned int subbuf_index;
	293	int ret;
	294
	295
	296	ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF,
	297	&subbuf_index);
	298	if(ret != 0) {
	299	perror("Error in reserving sub buffer");
	300	goto error;
	301	}
	302
	303	ret = TEMP_FAILURE_RETRY(write(pair->trace,
	304	pair->mmap + (subbuf_index * pair->subbuf_size),
	305	pair->subbuf_size));
	306
	307	if(ret != 0) {
	308	perror("Error in writing to file");
	309	goto error;
	310	}
	311
	312
	313	ret = ioctl(pair->channel, RELAYFS_PUT_SUBBUF);
	314	if(ret != 0) {
	315	perror("Error in unreserving sub buffer");
	316	goto error;
	317	}
	318
	319	return 0;
	320	error:
	321	return -1;
	322	}
	323
	324
90ccaa9a	325	/* read_channels
	326	*
	327	* Read the realyfs channels and write them in the paired tracefiles.
	328	*
	329	* @fd_pairs : paired channels and trace files.
	330	*
	331	* returns 0 on success, -1 on error.
	332	*
	333	* Note that the high priority polled channels are consumed first. We then poll
	334	* again to see if these channels are still in priority. Only when no
	335	* high priority channel is left, we start reading low priority channels.
	336	*
	337	* Note that a channel is considered high priority when the buffer is almost
	338	* full.
	339	*/
617de8e1	340
	341	int read_channels(struct channel_trace_fd *fd_pairs)
	342	{
90ccaa9a	343	struct pollfd *pollfd;
1d483eea	344	int i,j;
1d483eea	345	int num_rdy, num_hup;
4f45ea55	346	int high_prio;
1d483eea	347	int ret;
	348
	349	/* Get the subbuf sizes and number */
	350
	351	for(i=0;i<fd_pairs->num_pairs;i++) {
	352	struct fd_pair *pair = &fd_pairs->pair[i];
90ccaa9a	353
1d483eea	354	ret = ioctl(pair->channel, RELAYFS_GET_N_SUBBUFS,
	355	&pair->n_subbufs);
	356	if(ret != 0) {
	357	perror("Error in getting the number of subbuffers");
	358	goto end;
	359	}
	360	ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF_SIZE,
	361	&pair->subbuf_size);
	362	if(ret != 0) {
	363	perror("Error in getting the size of the subbuffers");
	364	goto end;
	365	}
	366	}
	367
	368	/* Mmap each FD */
	369	for(i=0;i<fd_pairs->num_pairs;i++) {
	370	struct fd_pair *pair = &fd_pairs->pair[i];
	371
	372	pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs, PROT_READ,
	373	MAP_SHARED, pair->channel, 0);
	374	if(pair->mmap == MAP_FAILED) {
	375	perror("Mmap error");
	376	goto munmap;
	377	}
	378	}
	379
	380
	381	/* Start polling the FD */
	382
90ccaa9a	383	pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd));
90ccaa9a	384
1d483eea	385	/* Note : index in pollfd is the same index as fd_pair->pair */
90ccaa9a	386	for(i=0;i<fd_pairs->num_pairs;i++) {
	387	pollfd[i].fd = fd_pairs->pair[i].channel;
	388	pollfd[i].events = POLLIN\|POLLPRI;
	389	}
	390
	391	while(1) {
4f45ea55	392	high_prio = 0;
1d483eea	393	num_hup = 0;
	394	#ifdef DEBUG
	395	printf("Press a key for next poll...\n");
	396	char buf[1];
	397	read(STDIN_FILENO, &buf, 1);
	398	printf("Next poll :\n");
	399	#endif //DEBUG
	400
	401	/* Have we received a signal ? */
	402	if(quit_program) break;
	403
90ccaa9a	404	num_rdy = poll(pollfd, fd_pairs->num_pairs, -1);
	405	if(num_rdy == -1) {
	406	perror("Poll error");
1d483eea	407	goto free_fd;
90ccaa9a	408	}
	409
	410	printf("Data received\n");
	411
	412	for(i=0;i<fd_pairs->num_pairs;i++) {
	413	switch(pollfd[i].revents) {
	414	case POLLERR:
	415	printf("Error returned in polling fd %d.\n", pollfd[i].fd);
1d483eea	416	num_hup++;
90ccaa9a	417	break;
	418	case POLLHUP:
	419	printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd);
1d483eea	420	num_hup++;
90ccaa9a	421	break;
	422	case POLLNVAL:
	423	printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd);
1d483eea	424	num_hup++;
90ccaa9a	425	break;
90ccaa9a	426	case POLLPRI:
1d483eea	427	printf("Urgent read on fd %d\n", pollfd[i].fd);
90ccaa9a	428	/* Take care of high priority channels first. */
4f45ea55	429	high_prio = 1;
1d483eea	430	ret \|= read_subbuffer(&fd_pairs->pair[i]);
90ccaa9a	431	break;
4f45ea55	432	}
90ccaa9a	433	}
1d483eea	434	/* If every FD has hung up, we end the read loop here */
1d483eea	435	if(num_hup == fd_pairs->num_pairs) break;
90ccaa9a	436
4f45ea55	437	if(!high_prio) {
	438	for(i=0;i<fd_pairs->num_pairs;i++) {
	439	switch(pollfd[i].revents) {
	440	case POLLIN:
	441	/* Take care of low priority channels. */
1d483eea	442	printf("Normal read on fd %d\n", pollfd[i].fd);
1d483eea	443	ret \|= read_subbuffer(&fd_pairs->pair[i]);
4f45ea55	444	break;
	445	}
	446	}
90ccaa9a	447	}
	448
	449	}
	450
1d483eea	451	free_fd:
90ccaa9a	452	free(pollfd);
90ccaa9a	453
1d483eea	454	/* munmap only the successfully mmapped indexes */
	455	i = fd_pairs->num_pairs;
	456	munmap:
	457	/* Munmap each FD */
	458	for(j=0;j<i;j++) {
	459	struct fd_pair *pair = &fd_pairs->pair[j];
	460	int err_ret;
	461
	462	err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
	463	if(err_ret != 0) {
	464	perror("Error in munmap");
	465	}
	466	ret \|= err_ret;
	467	}
	468
	469	end:
	470	return ret;
617de8e1	471	}
	472
	473
	474	void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs)
	475	{
90ccaa9a	476	int i;
90ccaa9a	477	int ret;
617de8e1	478
90ccaa9a	479	for(i=0;i<fd_pairs->num_pairs;i++) {
	480	ret = close(fd_pairs->pair[i].channel);
	481	if(ret == -1) perror("Close error on channel");
	482	ret = close(fd_pairs->pair[i].trace);
	483	if(ret == -1) perror("Close error on trace");
	484	}
	485	free(fd_pairs->pair);
617de8e1	486	}
	487
	488	int main(int argc, char ** argv)
	489	{
	490	int ret;
	491	pid_t pid;
	492	struct channel_trace_fd fd_pairs = { NULL, 0 };
1d483eea	493	struct sigaction act;
617de8e1	494
	495	ret = parse_arguments(argc, argv);
	496
	497	if(ret != 0) show_arguments();
	498	if(ret < 0) return EINVAL;
	499	if(ret > 0) return 0;
	500
	501	show_info();
	502
	503	if(daemon_mode) {
	504	pid = fork();
	505
	506	if(pid > 0) {
	507	/* parent */
	508	return 0;
	509	} else if(pid < 0) {
	510	/* error */
	511	printf("An error occured while forking.\n");
	512	return -1;
	513	}
	514	/* else, we are the child, continue... */
	515	}
	516
1d483eea	517	/* Connect the signal handlers */
	518	act.sa_handler = handler;
	519	act.sa_flags = 0;
	520	sigemptyset(&(act.sa_mask));
	521	sigaddset(&(act.sa_mask), SIGTERM);
	522	sigaddset(&(act.sa_mask), SIGQUIT);
	523	sigaddset(&(act.sa_mask), SIGINT);
	524	sigaction(SIGTERM, &act, NULL);
	525	sigaction(SIGQUIT, &act, NULL);
	526	sigaction(SIGINT, &act, NULL);
	527
	528	//return 0;
617de8e1	529	if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs))
90ccaa9a	530	goto close_channel;
617de8e1	531
	532	ret = read_channels(&fd_pairs);
	533
90ccaa9a	534	close_channel:
617de8e1	535	close_channel_trace_pairs(&fd_pairs);
617de8e1	536
617de8e1	537	return ret;
617de8e1	538	}