[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>
 */

#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;
static int	sig_parent = 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 SIGIO 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("-s            Send SIGIO to parent when ready for IO.\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;
					case 's':
						sig_parent = 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 && append_mode) {
			printf("Appending to directory %s as resquested\n", subtrace_name);
		} else {
			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;
	}

	/* Signal the parent that ready for IO */
	if(sig_parent) kill(getppid(), SIGIO);

	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;
	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
0bb647f5	13	#ifdef HAVE_CONFIG_H
469206ed	14	#include <config.h>
0bb647f5	15	#endif
	16
	17	#define _GNU_SOURCE
617de8e1	18	#include <stdio.h>
1d483eea	19	#include <unistd.h>
617de8e1	20	#include <errno.h>
	21	#include <sys/types.h>
	22	#include <sys/stat.h>
617de8e1	23	#include <stdlib.h>
	24	#include <dirent.h>
	25	#include <string.h>
90ccaa9a	26	#include <fcntl.h>
90ccaa9a	27	#include <sys/poll.h>
1d483eea	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
617de8e1	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;
1d483eea	56	unsigned int n_subbufs;
	57	unsigned int subbuf_size;
	58	void *mmap;
617de8e1	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;
90ccaa9a	69	static int append_mode = 0;
469206ed	70	static int sig_parent = 0;
1d483eea	71	volatile static int quit_program = 0; /* For signal handler */
617de8e1	72
	73	/* Args :
	74	*
	75	* -t directory Directory name of the trace to write to. Will be created.
	76	* -c directory Root directory of the relayfs trace channels.
	77	* -d Run in background (daemon).
90ccaa9a	78	* -a Trace append mode.
469206ed	79	* -s Send SIGIO to parent when ready for IO.
617de8e1	80	*/
	81	void show_arguments(void)
	82	{
	83	printf("Please use the following arguments :\n");
	84	printf("\n");
	85	printf("-t directory Directory name of the trace to write to.\n"
	86	" It will be created.\n");
	87	printf("-c directory Root directory of the relayfs trace channels.\n");
	88	printf("-d Run in background (daemon).\n");
90ccaa9a	89	printf("-a Append to an possibly existing trace.\n");
469206ed	90	printf("-s Send SIGIO to parent when ready for IO.\n");
617de8e1	91	printf("\n");
	92	}
	93
	94
	95	/* parse_arguments
	96	*
	97	* Parses the command line arguments.
	98	*
	99	* Returns 1 if the arguments were correct, but doesn't ask for program
	100	* continuation. Returns -1 if the arguments are incorrect, or 0 if OK.
	101	*/
	102	int parse_arguments(int argc, char **argv)
	103	{
	104	int ret = 0;
	105	int argn = 1;
	106
	107	if(argc == 2) {
	108	if(strcmp(argv[1], "-h") == 0) {
	109	return 1;
	110	}
	111	}
	112
90ccaa9a	113	while(argn < argc) {
617de8e1	114
	115	switch(argv[argn][0]) {
	116	case '-':
	117	switch(argv[argn][1]) {
	118	case 't':
90ccaa9a	119	if(argn+1 < argc) {
	120	trace_name = argv[argn+1];
	121	argn++;
	122	}
617de8e1	123	break;
617de8e1	124	case 'c':
90ccaa9a	125	if(argn+1 < argc) {
	126	channel_name = argv[argn+1];
	127	argn++;
	128	}
617de8e1	129	break;
	130	case 'd':
	131	daemon_mode = 1;
	132	break;
90ccaa9a	133	case 'a':
	134	append_mode = 1;
	135	break;
469206ed	136	case 's':
	137	sig_parent = 1;
	138	break;
617de8e1	139	default:
	140	printf("Invalid argument '%s'.\n", argv[argn]);
	141	printf("\n");
	142	ret = -1;
	143	}
	144	break;
	145	default:
	146	printf("Invalid argument '%s'.\n", argv[argn]);
	147	printf("\n");
	148	ret = -1;
	149	}
	150	argn++;
	151	}
	152
	153	if(trace_name == NULL) {
	154	printf("Please specify a trace name.\n");
	155	printf("\n");
	156	ret = -1;
	157	}
	158
	159	if(channel_name == NULL) {
	160	printf("Please specify a channel name.\n");
	161	printf("\n");
	162	ret = -1;
	163	}
	164
	165	return ret;
	166	}
	167
	168	void show_info(void)
	169	{
	170	printf("Linux Trace Toolkit Trace Daemon\n");
	171	printf("\n");
	172	printf("Reading from relayfs directory : %s\n", channel_name);
	173	printf("Writing to trace directory : %s\n", trace_name);
	174	printf("\n");
	175	}
	176
	177
1d483eea	178	/* signal handling */
	179
	180	static void handler(int signo)
	181	{
	182	printf("Signal %d received : exiting cleanly\n", signo);
	183	quit_program = 1;
	184	}
	185
	186
	187
617de8e1	188	int open_channel_trace_pairs(char subchannel_name, char subtrace_name,
	189	struct channel_trace_fd *fd_pairs)
	190	{
	191	DIR *channel_dir = opendir(subchannel_name);
	192	struct dirent *entry;
	193	struct stat stat_buf;
	194	int ret;
	195	char path_channel[PATH_MAX];
	196	int path_channel_len;
	197	char *path_channel_ptr;
	198	char path_trace[PATH_MAX];
	199	int path_trace_len;
	200	char *path_trace_ptr;
d304b1dd	201	int open_ret = 0;
617de8e1	202
	203	if(channel_dir == NULL) {
	204	perror(subchannel_name);
d304b1dd	205	open_ret = ENOENT;
d304b1dd	206	goto end;
617de8e1	207	}
617de8e1	208
617de8e1	209	printf("Creating trace subdirectory %s\n", subtrace_name);
	210	ret = mkdir(subtrace_name, S_IRWXU\|S_IRWXG\|S_IRWXO);
	211	if(ret == -1) {
90ccaa9a	212	if(errno == EEXIST && append_mode) {
	213	printf("Appending to directory %s as resquested\n", subtrace_name);
	214	} else {
	215	perror(subtrace_name);
d304b1dd	216	open_ret = -1;
d304b1dd	217	goto end;
90ccaa9a	218	}
617de8e1	219	}
	220
	221	strncpy(path_channel, subchannel_name, PATH_MAX-1);
	222	path_channel_len = strlen(path_channel);
	223	path_channel[path_channel_len] = '/';
	224	path_channel_len++;
	225	path_channel_ptr = path_channel + path_channel_len;
	226
	227	strncpy(path_trace, subtrace_name, PATH_MAX-1);
	228	path_trace_len = strlen(path_trace);
	229	path_trace[path_trace_len] = '/';
	230	path_trace_len++;
	231	path_trace_ptr = path_trace + path_trace_len;
	232
	233	while((entry = readdir(channel_dir)) != NULL) {
	234
	235	if(entry->d_name[0] == '.') continue;
	236
	237	strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
	238	strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len);
	239
	240	ret = stat(path_channel, &stat_buf);
	241	if(ret == -1) {
	242	perror(path_channel);
	243	continue;
	244	}
	245
	246	printf("Channel file : %s\n", path_channel);
	247
	248	if(S_ISDIR(stat_buf.st_mode)) {
	249
	250	printf("Entering channel subdirectory...\n");
	251	ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs);
	252	if(ret < 0) continue;
90ccaa9a	253	} else if(S_ISREG(stat_buf.st_mode)) {
	254	printf("Opening file.\n");
	255
	256	fd_pairs->pair = realloc(fd_pairs->pair,
	257	++fd_pairs->num_pairs * sizeof(struct fd_pair));
	258
	259	/* Open the channel in read mode */
	260	fd_pairs->pair[fd_pairs->num_pairs-1].channel =
	261	open(path_channel, O_RDONLY \| O_NONBLOCK);
	262	if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
	263	perror(path_channel);
469206ed	264	fd_pairs->num_pairs--;
469206ed	265	continue;
90ccaa9a	266	}
	267	/* Open the trace in write mode, only append if append_mode */
	268	ret = stat(path_trace, &stat_buf);
	269	if(ret == 0) {
	270	if(append_mode) {
3357d360	271	printf("Appending to file %s as requested\n", path_trace);
90ccaa9a	272
	273	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	274	open(path_trace, O_WRONLY\|O_APPEND,
	275	S_IRWXU\|S_IRWXG\|S_IRWXO);
	276
	277	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	278	perror(path_trace);
	279	}
	280	} else {
	281	printf("File %s exists, cannot open. Try append mode.\n", path_trace);
d304b1dd	282	open_ret = -1;
d304b1dd	283	goto end;
90ccaa9a	284	}
	285	} else {
	286	if(errno == ENOENT) {
	287	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	288	open(path_trace, O_WRONLY\|O_CREAT\|O_EXCL,
	289	S_IRWXU\|S_IRWXG\|S_IRWXO);
	290	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	291	perror(path_trace);
	292	}
	293	}
	294	}
617de8e1	295	}
617de8e1	296	}
617de8e1	297
d304b1dd	298	end:
617de8e1	299	closedir(channel_dir);
617de8e1	300
d304b1dd	301	return open_ret;
617de8e1	302	}
617de8e1	303
1d483eea	304
	305	int read_subbuffer(struct fd_pair *pair)
	306	{
	307	unsigned int subbuf_index;
469206ed	308	int err, ret;
1d483eea	309
1d483eea	310
469206ed	311	err = ioctl(pair->channel, RELAYFS_GET_SUBBUF,
1d483eea	312	&subbuf_index);
469206ed	313	printf("index : %u\n", subbuf_index);
469206ed	314	if(err != 0) {
1d483eea	315	perror("Error in reserving sub buffer");
469206ed	316	ret = -EPERM;
469206ed	317	goto get_error;
1d483eea	318	}
469206ed	319
469206ed	320	err = TEMP_FAILURE_RETRY(write(pair->trace,
1d483eea	321	pair->mmap + (subbuf_index * pair->subbuf_size),
1d483eea	322	pair->subbuf_size));
469206ed	323
469206ed	324	if(err < 0) {
1d483eea	325	perror("Error in writing to file");
469206ed	326	ret = err;
469206ed	327	goto write_error;
1d483eea	328	}
	329
	330
469206ed	331	write_error:
	332	err = ioctl(pair->channel, RELAYFS_PUT_SUBBUF);
	333	if(err != 0) {
1d483eea	334	perror("Error in unreserving sub buffer");
469206ed	335	ret = -EPERM;
469206ed	336	goto get_error;
1d483eea	337	}
1d483eea	338
469206ed	339	get_error:
469206ed	340	return ret;
1d483eea	341	}
	342
	343
90ccaa9a	344	/* read_channels
	345	*
	346	* Read the realyfs channels and write them in the paired tracefiles.
	347	*
	348	* @fd_pairs : paired channels and trace files.
	349	*
	350	* returns 0 on success, -1 on error.
	351	*
	352	* Note that the high priority polled channels are consumed first. We then poll
	353	* again to see if these channels are still in priority. Only when no
	354	* high priority channel is left, we start reading low priority channels.
	355	*
	356	* Note that a channel is considered high priority when the buffer is almost
	357	* full.
	358	*/
617de8e1	359
	360	int read_channels(struct channel_trace_fd *fd_pairs)
	361	{
90ccaa9a	362	struct pollfd *pollfd;
1d483eea	363	int i,j;
1d483eea	364	int num_rdy, num_hup;
4f45ea55	365	int high_prio;
1d483eea	366	int ret;
1d483eea	367
469206ed	368	if(fd_pairs->num_pairs <= 0) {
	369	printf("No channel to read\n");
	370	goto end;
	371	}
	372
1d483eea	373	/* Get the subbuf sizes and number */
	374
	375	for(i=0;i<fd_pairs->num_pairs;i++) {
	376	struct fd_pair *pair = &fd_pairs->pair[i];
90ccaa9a	377
1d483eea	378	ret = ioctl(pair->channel, RELAYFS_GET_N_SUBBUFS,
	379	&pair->n_subbufs);
	380	if(ret != 0) {
	381	perror("Error in getting the number of subbuffers");
	382	goto end;
	383	}
	384	ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF_SIZE,
	385	&pair->subbuf_size);
	386	if(ret != 0) {
	387	perror("Error in getting the size of the subbuffers");
	388	goto end;
	389	}
	390	}
	391
	392	/* Mmap each FD */
	393	for(i=0;i<fd_pairs->num_pairs;i++) {
	394	struct fd_pair *pair = &fd_pairs->pair[i];
	395
	396	pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs, PROT_READ,
	397	MAP_SHARED, pair->channel, 0);
	398	if(pair->mmap == MAP_FAILED) {
	399	perror("Mmap error");
	400	goto munmap;
	401	}
	402	}
	403
	404
	405	/* Start polling the FD */
	406
90ccaa9a	407	pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd));
90ccaa9a	408
1d483eea	409	/* Note : index in pollfd is the same index as fd_pair->pair */
90ccaa9a	410	for(i=0;i<fd_pairs->num_pairs;i++) {
	411	pollfd[i].fd = fd_pairs->pair[i].channel;
	412	pollfd[i].events = POLLIN\|POLLPRI;
	413	}
	414
469206ed	415	/* Signal the parent that ready for IO */
	416	if(sig_parent) kill(getppid(), SIGIO);
	417
90ccaa9a	418	while(1) {
4f45ea55	419	high_prio = 0;
1d483eea	420	num_hup = 0;
	421	#ifdef DEBUG
	422	printf("Press a key for next poll...\n");
	423	char buf[1];
	424	read(STDIN_FILENO, &buf, 1);
469206ed	425	printf("Next poll (polling %d fd) :\n", fd_pairs->num_pairs);
1d483eea	426	#endif //DEBUG
	427
	428	/* Have we received a signal ? */
	429	if(quit_program) break;
	430
90ccaa9a	431	num_rdy = poll(pollfd, fd_pairs->num_pairs, -1);
	432	if(num_rdy == -1) {
	433	perror("Poll error");
1d483eea	434	goto free_fd;
90ccaa9a	435	}
	436
	437	printf("Data received\n");
	438
	439	for(i=0;i<fd_pairs->num_pairs;i++) {
	440	switch(pollfd[i].revents) {
	441	case POLLERR:
	442	printf("Error returned in polling fd %d.\n", pollfd[i].fd);
1d483eea	443	num_hup++;
90ccaa9a	444	break;
	445	case POLLHUP:
	446	printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd);
1d483eea	447	num_hup++;
90ccaa9a	448	break;
	449	case POLLNVAL:
	450	printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd);
1d483eea	451	num_hup++;
90ccaa9a	452	break;
90ccaa9a	453	case POLLPRI:
1d483eea	454	printf("Urgent read on fd %d\n", pollfd[i].fd);
90ccaa9a	455	/* Take care of high priority channels first. */
4f45ea55	456	high_prio = 1;
1d483eea	457	ret \|= read_subbuffer(&fd_pairs->pair[i]);
90ccaa9a	458	break;
4f45ea55	459	}
90ccaa9a	460	}
1d483eea	461	/* If every FD has hung up, we end the read loop here */
1d483eea	462	if(num_hup == fd_pairs->num_pairs) break;
90ccaa9a	463
4f45ea55	464	if(!high_prio) {
	465	for(i=0;i<fd_pairs->num_pairs;i++) {
	466	switch(pollfd[i].revents) {
	467	case POLLIN:
	468	/* Take care of low priority channels. */
1d483eea	469	printf("Normal read on fd %d\n", pollfd[i].fd);
1d483eea	470	ret \|= read_subbuffer(&fd_pairs->pair[i]);
4f45ea55	471	break;
	472	}
	473	}
90ccaa9a	474	}
	475
	476	}
	477
1d483eea	478	free_fd:
90ccaa9a	479	free(pollfd);
90ccaa9a	480
1d483eea	481	/* munmap only the successfully mmapped indexes */
	482	i = fd_pairs->num_pairs;
	483	munmap:
	484	/* Munmap each FD */
	485	for(j=0;j<i;j++) {
	486	struct fd_pair *pair = &fd_pairs->pair[j];
	487	int err_ret;
	488
	489	err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
	490	if(err_ret != 0) {
	491	perror("Error in munmap");
	492	}
	493	ret \|= err_ret;
	494	}
	495
	496	end:
	497	return ret;
617de8e1	498	}
	499
	500
	501	void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs)
	502	{
90ccaa9a	503	int i;
90ccaa9a	504	int ret;
617de8e1	505
90ccaa9a	506	for(i=0;i<fd_pairs->num_pairs;i++) {
	507	ret = close(fd_pairs->pair[i].channel);
	508	if(ret == -1) perror("Close error on channel");
	509	ret = close(fd_pairs->pair[i].trace);
	510	if(ret == -1) perror("Close error on trace");
	511	}
	512	free(fd_pairs->pair);
617de8e1	513	}
	514
	515	int main(int argc, char ** argv)
	516	{
	517	int ret;
	518	pid_t pid;
	519	struct channel_trace_fd fd_pairs = { NULL, 0 };
1d483eea	520	struct sigaction act;
617de8e1	521
	522	ret = parse_arguments(argc, argv);
	523
	524	if(ret != 0) show_arguments();
	525	if(ret < 0) return EINVAL;
	526	if(ret > 0) return 0;
	527
	528	show_info();
	529
	530	if(daemon_mode) {
	531	pid = fork();
	532
	533	if(pid > 0) {
	534	/* parent */
	535	return 0;
	536	} else if(pid < 0) {
	537	/* error */
	538	printf("An error occured while forking.\n");
	539	return -1;
	540	}
	541	/* else, we are the child, continue... */
	542	}
	543
1d483eea	544	/* Connect the signal handlers */
	545	act.sa_handler = handler;
	546	act.sa_flags = 0;
	547	sigemptyset(&(act.sa_mask));
	548	sigaddset(&(act.sa_mask), SIGTERM);
	549	sigaddset(&(act.sa_mask), SIGQUIT);
	550	sigaddset(&(act.sa_mask), SIGINT);
	551	sigaction(SIGTERM, &act, NULL);
	552	sigaction(SIGQUIT, &act, NULL);
	553	sigaction(SIGINT, &act, NULL);
	554
	555	//return 0;
617de8e1	556	if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs))
90ccaa9a	557	goto close_channel;
617de8e1	558
	559	ret = read_channels(&fd_pairs);
	560
90ccaa9a	561	close_channel:
617de8e1	562	close_channel_trace_pairs(&fd_pairs);
617de8e1	563
617de8e1	564	return ret;
617de8e1	565	}