[lttv.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>
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#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.
 * -s							Send SIGUSR1 to parent when ready for IO.
 */
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;
  int open_ret = 0;

	if(channel_dir == NULL) {
		perror(subchannel_name);
		open_ret = ENOENT;
    goto end;
	}

	printf("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;
	
	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);
				fd_pairs->num_pairs--;
				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("Appending to file %s as requested\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);
					open_ret = -1;
          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);
					}
				}
			}
		}
	}
	
end:
	closedir(channel_dir);

	return open_ret;
}


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


	err = ioctl(pair->channel, RELAYFS_GET_SUBBUF, 
								&subbuf_index);
	printf("index : %u\n", subbuf_index);
	if(err != 0) {
		perror("Error in reserving sub buffer");
		ret = -EPERM;
		goto get_error;
	}
	
	err = TEMP_FAILURE_RETRY(write(pair->trace,
				pair->mmap + (subbuf_index * pair->subbuf_size),
				pair->subbuf_size));

	if(err < 0) {
		perror("Error in writing to file");
		ret = err;
		goto write_error;
	}


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

get_error:
	return ret;
}


/* 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;

	if(fd_pairs->num_pairs <= 0) {
		printf("No channel to read\n");
		goto end;
	}
	
	/* 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 (polling %d fd) :\n", fd_pairs->num_pairs);
#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;
	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) {
		ret = daemon(0, 0);
    
    if(ret == -1) {
      perror("An error occured while daemonizing.");
      exit(-1);
    }
  }

	/* 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
6cecb9cf	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
4e4d11b3	13	#ifdef HAVE_CONFIG_H
13474e75	14	#include <config.h>
4e4d11b3	15	#endif
	16
	17	#define _GNU_SOURCE
6cecb9cf	18	#include <stdio.h>
af4061b2	19	#include <unistd.h>
6cecb9cf	20	#include <errno.h>
	21	#include <sys/types.h>
	22	#include <sys/stat.h>
6cecb9cf	23	#include <stdlib.h>
	24	#include <dirent.h>
	25	#include <string.h>
9e7dbe44	26	#include <fcntl.h>
9e7dbe44	27	#include <sys/poll.h>
af4061b2	28	#include <sys/mman.h>
	29	#include <signal.h>
	30
	31	/* Relayfs IOCTL */
	32	#include <asm/ioctl.h>
	33	#include <asm/types.h>
	34
	35	/* Get the next sub buffer that can be read. */
	36	#define RELAYFS_GET_SUBBUF _IOR(0xF4, 0x00,__u32)
	37	/* Release the oldest reserved (by "get") sub buffer. */
	38	#define RELAYFS_PUT_SUBBUF _IO(0xF4, 0x01)
	39	/* returns the number of sub buffers in the per cpu channel. */
	40	#define RELAYFS_GET_N_SUBBUFS _IOR(0xF4, 0x02,__u32)
	41	/* returns the size of the sub buffers. */
	42	#define RELAYFS_GET_SUBBUF_SIZE _IOR(0xF4, 0x03,__u32)
	43
	44
6cecb9cf	45
	46	enum {
	47	GET_SUBBUF,
	48	PUT_SUBBUF,
	49	GET_N_BUBBUFS,
	50	GET_SUBBUF_SIZE
	51	};
	52
	53	struct fd_pair {
	54	int channel;
	55	int trace;
af4061b2	56	unsigned int n_subbufs;
	57	unsigned int subbuf_size;
	58	void *mmap;
6cecb9cf	59	};
	60
	61	struct channel_trace_fd {
	62	struct fd_pair *pair;
	63	int num_pairs;
	64	};
	65
	66	static char *trace_name = NULL;
	67	static char *channel_name = NULL;
	68	static int daemon_mode = 0;
9e7dbe44	69	static int append_mode = 0;
af4061b2	70	volatile static int quit_program = 0; /* For signal handler */
6cecb9cf	71
	72	/* Args :
	73	*
	74	* -t directory Directory name of the trace to write to. Will be created.
	75	* -c directory Root directory of the relayfs trace channels.
	76	* -d Run in background (daemon).
9e7dbe44	77	* -a Trace append mode.
86a65fdb	78	* -s Send SIGUSR1 to parent when ready for IO.
6cecb9cf	79	*/
	80	void show_arguments(void)
	81	{
	82	printf("Please use the following arguments :\n");
	83	printf("\n");
	84	printf("-t directory Directory name of the trace to write to.\n"
	85	" It will be created.\n");
	86	printf("-c directory Root directory of the relayfs trace channels.\n");
	87	printf("-d Run in background (daemon).\n");
9e7dbe44	88	printf("-a Append to an possibly existing trace.\n");
6cecb9cf	89	printf("\n");
	90	}
	91
	92
	93	/* parse_arguments
	94	*
	95	* Parses the command line arguments.
	96	*
	97	* Returns 1 if the arguments were correct, but doesn't ask for program
	98	* continuation. Returns -1 if the arguments are incorrect, or 0 if OK.
	99	*/
	100	int parse_arguments(int argc, char **argv)
	101	{
	102	int ret = 0;
	103	int argn = 1;
	104
	105	if(argc == 2) {
	106	if(strcmp(argv[1], "-h") == 0) {
	107	return 1;
	108	}
	109	}
	110
9e7dbe44	111	while(argn < argc) {
6cecb9cf	112
	113	switch(argv[argn][0]) {
	114	case '-':
	115	switch(argv[argn][1]) {
	116	case 't':
9e7dbe44	117	if(argn+1 < argc) {
	118	trace_name = argv[argn+1];
	119	argn++;
	120	}
6cecb9cf	121	break;
6cecb9cf	122	case 'c':
9e7dbe44	123	if(argn+1 < argc) {
	124	channel_name = argv[argn+1];
	125	argn++;
	126	}
6cecb9cf	127	break;
	128	case 'd':
	129	daemon_mode = 1;
	130	break;
9e7dbe44	131	case 'a':
	132	append_mode = 1;
	133	break;
6cecb9cf	134	default:
	135	printf("Invalid argument '%s'.\n", argv[argn]);
	136	printf("\n");
	137	ret = -1;
	138	}
	139	break;
	140	default:
	141	printf("Invalid argument '%s'.\n", argv[argn]);
	142	printf("\n");
	143	ret = -1;
	144	}
	145	argn++;
	146	}
	147
	148	if(trace_name == NULL) {
	149	printf("Please specify a trace name.\n");
	150	printf("\n");
	151	ret = -1;
	152	}
	153
	154	if(channel_name == NULL) {
	155	printf("Please specify a channel name.\n");
	156	printf("\n");
	157	ret = -1;
	158	}
	159
	160	return ret;
	161	}
	162
	163	void show_info(void)
	164	{
	165	printf("Linux Trace Toolkit Trace Daemon\n");
	166	printf("\n");
	167	printf("Reading from relayfs directory : %s\n", channel_name);
	168	printf("Writing to trace directory : %s\n", trace_name);
	169	printf("\n");
	170	}
	171
	172
af4061b2	173	/* signal handling */
	174
	175	static void handler(int signo)
	176	{
	177	printf("Signal %d received : exiting cleanly\n", signo);
	178	quit_program = 1;
	179	}
	180
	181
	182
6cecb9cf	183	int open_channel_trace_pairs(char subchannel_name, char subtrace_name,
	184	struct channel_trace_fd *fd_pairs)
	185	{
	186	DIR *channel_dir = opendir(subchannel_name);
	187	struct dirent *entry;
	188	struct stat stat_buf;
	189	int ret;
	190	char path_channel[PATH_MAX];
	191	int path_channel_len;
	192	char *path_channel_ptr;
	193	char path_trace[PATH_MAX];
	194	int path_trace_len;
	195	char *path_trace_ptr;
02ba971e	196	int open_ret = 0;
6cecb9cf	197
	198	if(channel_dir == NULL) {
	199	perror(subchannel_name);
02ba971e	200	open_ret = ENOENT;
02ba971e	201	goto end;
6cecb9cf	202	}
6cecb9cf	203
6cecb9cf	204	printf("Creating trace subdirectory %s\n", subtrace_name);
	205	ret = mkdir(subtrace_name, S_IRWXU\|S_IRWXG\|S_IRWXO);
	206	if(ret == -1) {
3986d00b	207	if(errno != EEXIST) {
9e7dbe44	208	perror(subtrace_name);
02ba971e	209	open_ret = -1;
02ba971e	210	goto end;
9e7dbe44	211	}
6cecb9cf	212	}
	213
	214	strncpy(path_channel, subchannel_name, PATH_MAX-1);
	215	path_channel_len = strlen(path_channel);
	216	path_channel[path_channel_len] = '/';
	217	path_channel_len++;
	218	path_channel_ptr = path_channel + path_channel_len;
	219
	220	strncpy(path_trace, subtrace_name, PATH_MAX-1);
	221	path_trace_len = strlen(path_trace);
	222	path_trace[path_trace_len] = '/';
	223	path_trace_len++;
	224	path_trace_ptr = path_trace + path_trace_len;
	225
	226	while((entry = readdir(channel_dir)) != NULL) {
	227
	228	if(entry->d_name[0] == '.') continue;
	229
	230	strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
	231	strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len);
	232
	233	ret = stat(path_channel, &stat_buf);
	234	if(ret == -1) {
	235	perror(path_channel);
	236	continue;
	237	}
	238
	239	printf("Channel file : %s\n", path_channel);
	240
	241	if(S_ISDIR(stat_buf.st_mode)) {
	242
	243	printf("Entering channel subdirectory...\n");
	244	ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs);
	245	if(ret < 0) continue;
9e7dbe44	246	} else if(S_ISREG(stat_buf.st_mode)) {
	247	printf("Opening file.\n");
	248
	249	fd_pairs->pair = realloc(fd_pairs->pair,
	250	++fd_pairs->num_pairs * sizeof(struct fd_pair));
	251
	252	/* Open the channel in read mode */
	253	fd_pairs->pair[fd_pairs->num_pairs-1].channel =
	254	open(path_channel, O_RDONLY \| O_NONBLOCK);
	255	if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
	256	perror(path_channel);
13474e75	257	fd_pairs->num_pairs--;
13474e75	258	continue;
9e7dbe44	259	}
	260	/* Open the trace in write mode, only append if append_mode */
	261	ret = stat(path_trace, &stat_buf);
	262	if(ret == 0) {
	263	if(append_mode) {
251b5c5e	264	printf("Appending to file %s as requested\n", path_trace);
9e7dbe44	265
	266	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	267	open(path_trace, O_WRONLY\|O_APPEND,
	268	S_IRWXU\|S_IRWXG\|S_IRWXO);
	269
	270	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	271	perror(path_trace);
	272	}
	273	} else {
	274	printf("File %s exists, cannot open. Try append mode.\n", path_trace);
02ba971e	275	open_ret = -1;
02ba971e	276	goto end;
9e7dbe44	277	}
	278	} else {
	279	if(errno == ENOENT) {
	280	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	281	open(path_trace, O_WRONLY\|O_CREAT\|O_EXCL,
	282	S_IRWXU\|S_IRWXG\|S_IRWXO);
	283	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	284	perror(path_trace);
	285	}
	286	}
	287	}
6cecb9cf	288	}
6cecb9cf	289	}
6cecb9cf	290
02ba971e	291	end:
6cecb9cf	292	closedir(channel_dir);
6cecb9cf	293
02ba971e	294	return open_ret;
6cecb9cf	295	}
6cecb9cf	296
af4061b2	297
	298	int read_subbuffer(struct fd_pair *pair)
	299	{
	300	unsigned int subbuf_index;
13474e75	301	int err, ret;
af4061b2	302
af4061b2	303
13474e75	304	err = ioctl(pair->channel, RELAYFS_GET_SUBBUF,
af4061b2	305	&subbuf_index);
13474e75	306	printf("index : %u\n", subbuf_index);
13474e75	307	if(err != 0) {
af4061b2	308	perror("Error in reserving sub buffer");
13474e75	309	ret = -EPERM;
13474e75	310	goto get_error;
af4061b2	311	}
13474e75	312
13474e75	313	err = TEMP_FAILURE_RETRY(write(pair->trace,
af4061b2	314	pair->mmap + (subbuf_index * pair->subbuf_size),
af4061b2	315	pair->subbuf_size));
13474e75	316
13474e75	317	if(err < 0) {
af4061b2	318	perror("Error in writing to file");
13474e75	319	ret = err;
13474e75	320	goto write_error;
af4061b2	321	}
	322
	323
13474e75	324	write_error:
	325	err = ioctl(pair->channel, RELAYFS_PUT_SUBBUF);
	326	if(err != 0) {
af4061b2	327	perror("Error in unreserving sub buffer");
13474e75	328	ret = -EPERM;
13474e75	329	goto get_error;
af4061b2	330	}
af4061b2	331
13474e75	332	get_error:
13474e75	333	return ret;
af4061b2	334	}
	335
	336
9e7dbe44	337	/* read_channels
	338	*
	339	* Read the realyfs channels and write them in the paired tracefiles.
	340	*
	341	* @fd_pairs : paired channels and trace files.
	342	*
	343	* returns 0 on success, -1 on error.
	344	*
	345	* Note that the high priority polled channels are consumed first. We then poll
	346	* again to see if these channels are still in priority. Only when no
	347	* high priority channel is left, we start reading low priority channels.
	348	*
	349	* Note that a channel is considered high priority when the buffer is almost
	350	* full.
	351	*/
6cecb9cf	352
	353	int read_channels(struct channel_trace_fd *fd_pairs)
	354	{
9e7dbe44	355	struct pollfd *pollfd;
af4061b2	356	int i,j;
af4061b2	357	int num_rdy, num_hup;
68047576	358	int high_prio;
af4061b2	359	int ret;
af4061b2	360
13474e75	361	if(fd_pairs->num_pairs <= 0) {
	362	printf("No channel to read\n");
	363	goto end;
	364	}
	365
af4061b2	366	/* Get the subbuf sizes and number */
	367
	368	for(i=0;i<fd_pairs->num_pairs;i++) {
	369	struct fd_pair *pair = &fd_pairs->pair[i];
9e7dbe44	370
af4061b2	371	ret = ioctl(pair->channel, RELAYFS_GET_N_SUBBUFS,
	372	&pair->n_subbufs);
	373	if(ret != 0) {
	374	perror("Error in getting the number of subbuffers");
	375	goto end;
	376	}
	377	ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF_SIZE,
	378	&pair->subbuf_size);
	379	if(ret != 0) {
	380	perror("Error in getting the size of the subbuffers");
	381	goto end;
	382	}
	383	}
	384
	385	/* Mmap each FD */
	386	for(i=0;i<fd_pairs->num_pairs;i++) {
	387	struct fd_pair *pair = &fd_pairs->pair[i];
	388
	389	pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs, PROT_READ,
	390	MAP_SHARED, pair->channel, 0);
	391	if(pair->mmap == MAP_FAILED) {
	392	perror("Mmap error");
	393	goto munmap;
	394	}
	395	}
	396
	397
	398	/* Start polling the FD */
	399
9e7dbe44	400	pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd));
9e7dbe44	401
af4061b2	402	/* Note : index in pollfd is the same index as fd_pair->pair */
9e7dbe44	403	for(i=0;i<fd_pairs->num_pairs;i++) {
	404	pollfd[i].fd = fd_pairs->pair[i].channel;
	405	pollfd[i].events = POLLIN\|POLLPRI;
	406	}
	407
	408	while(1) {
68047576	409	high_prio = 0;
af4061b2	410	num_hup = 0;
	411	#ifdef DEBUG
	412	printf("Press a key for next poll...\n");
	413	char buf[1];
	414	read(STDIN_FILENO, &buf, 1);
13474e75	415	printf("Next poll (polling %d fd) :\n", fd_pairs->num_pairs);
af4061b2	416	#endif //DEBUG
	417
	418	/* Have we received a signal ? */
	419	if(quit_program) break;
	420
9e7dbe44	421	num_rdy = poll(pollfd, fd_pairs->num_pairs, -1);
	422	if(num_rdy == -1) {
	423	perror("Poll error");
af4061b2	424	goto free_fd;
9e7dbe44	425	}
	426
	427	printf("Data received\n");
	428
	429	for(i=0;i<fd_pairs->num_pairs;i++) {
	430	switch(pollfd[i].revents) {
	431	case POLLERR:
	432	printf("Error returned in polling fd %d.\n", pollfd[i].fd);
af4061b2	433	num_hup++;
9e7dbe44	434	break;
	435	case POLLHUP:
	436	printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd);
af4061b2	437	num_hup++;
9e7dbe44	438	break;
	439	case POLLNVAL:
	440	printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd);
af4061b2	441	num_hup++;
9e7dbe44	442	break;
9e7dbe44	443	case POLLPRI:
af4061b2	444	printf("Urgent read on fd %d\n", pollfd[i].fd);
9e7dbe44	445	/* Take care of high priority channels first. */
68047576	446	high_prio = 1;
af4061b2	447	ret \|= read_subbuffer(&fd_pairs->pair[i]);
9e7dbe44	448	break;
68047576	449	}
9e7dbe44	450	}
af4061b2	451	/* If every FD has hung up, we end the read loop here */
af4061b2	452	if(num_hup == fd_pairs->num_pairs) break;
9e7dbe44	453
68047576	454	if(!high_prio) {
	455	for(i=0;i<fd_pairs->num_pairs;i++) {
	456	switch(pollfd[i].revents) {
	457	case POLLIN:
	458	/* Take care of low priority channels. */
af4061b2	459	printf("Normal read on fd %d\n", pollfd[i].fd);
af4061b2	460	ret \|= read_subbuffer(&fd_pairs->pair[i]);
68047576	461	break;
	462	}
	463	}
9e7dbe44	464	}
	465
	466	}
	467
af4061b2	468	free_fd:
9e7dbe44	469	free(pollfd);
9e7dbe44	470
af4061b2	471	/* munmap only the successfully mmapped indexes */
	472	i = fd_pairs->num_pairs;
	473	munmap:
	474	/* Munmap each FD */
	475	for(j=0;j<i;j++) {
	476	struct fd_pair *pair = &fd_pairs->pair[j];
	477	int err_ret;
	478
	479	err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
	480	if(err_ret != 0) {
	481	perror("Error in munmap");
	482	}
	483	ret \|= err_ret;
	484	}
	485
	486	end:
	487	return ret;
6cecb9cf	488	}
	489
	490
	491	void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs)
	492	{
9e7dbe44	493	int i;
9e7dbe44	494	int ret;
6cecb9cf	495
9e7dbe44	496	for(i=0;i<fd_pairs->num_pairs;i++) {
	497	ret = close(fd_pairs->pair[i].channel);
	498	if(ret == -1) perror("Close error on channel");
	499	ret = close(fd_pairs->pair[i].trace);
	500	if(ret == -1) perror("Close error on trace");
	501	}
	502	free(fd_pairs->pair);
6cecb9cf	503	}
	504
	505	int main(int argc, char ** argv)
	506	{
	507	int ret;
6cecb9cf	508	struct channel_trace_fd fd_pairs = { NULL, 0 };
af4061b2	509	struct sigaction act;
6cecb9cf	510
	511	ret = parse_arguments(argc, argv);
	512
	513	if(ret != 0) show_arguments();
	514	if(ret < 0) return EINVAL;
	515	if(ret > 0) return 0;
	516
	517	show_info();
	518
	519	if(daemon_mode) {
4d20e474	520	ret = daemon(0, 0);
	521
	522	if(ret == -1) {
	523	perror("An error occured while daemonizing.");
	524	exit(-1);
	525	}
	526	}
6cecb9cf	527
af4061b2	528	/* Connect the signal handlers */
	529	act.sa_handler = handler;
	530	act.sa_flags = 0;
	531	sigemptyset(&(act.sa_mask));
	532	sigaddset(&(act.sa_mask), SIGTERM);
	533	sigaddset(&(act.sa_mask), SIGQUIT);
	534	sigaddset(&(act.sa_mask), SIGINT);
	535	sigaction(SIGTERM, &act, NULL);
	536	sigaction(SIGQUIT, &act, NULL);
	537	sigaction(SIGINT, &act, NULL);
	538
	539	//return 0;
6cecb9cf	540	if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs))
9e7dbe44	541	goto close_channel;
6cecb9cf	542
	543	ret = read_channels(&fd_pairs);
	544
9e7dbe44	545	close_channel:
6cecb9cf	546	close_channel_trace_pairs(&fd_pairs);
6cecb9cf	547
6cecb9cf	548	return ret;
6cecb9cf	549	}