[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;

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

	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);
				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);
					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 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;
	201
	202	if(channel_dir == NULL) {
	203	perror(subchannel_name);
	204	return ENOENT;
	205	}
	206
617de8e1	207	printf("Creating trace subdirectory %s\n", subtrace_name);
	208	ret = mkdir(subtrace_name, S_IRWXU\|S_IRWXG\|S_IRWXO);
	209	if(ret == -1) {
90ccaa9a	210	if(errno == EEXIST && append_mode) {
	211	printf("Appending to directory %s as resquested\n", subtrace_name);
	212	} else {
	213	perror(subtrace_name);
	214	return -1;
	215	}
617de8e1	216	}
	217
	218	strncpy(path_channel, subchannel_name, PATH_MAX-1);
	219	path_channel_len = strlen(path_channel);
	220	path_channel[path_channel_len] = '/';
	221	path_channel_len++;
	222	path_channel_ptr = path_channel + path_channel_len;
	223
	224	strncpy(path_trace, subtrace_name, PATH_MAX-1);
	225	path_trace_len = strlen(path_trace);
	226	path_trace[path_trace_len] = '/';
	227	path_trace_len++;
	228	path_trace_ptr = path_trace + path_trace_len;
	229
	230	while((entry = readdir(channel_dir)) != NULL) {
	231
	232	if(entry->d_name[0] == '.') continue;
	233
	234	strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
	235	strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len);
	236
	237	ret = stat(path_channel, &stat_buf);
	238	if(ret == -1) {
	239	perror(path_channel);
	240	continue;
	241	}
	242
	243	printf("Channel file : %s\n", path_channel);
	244
	245	if(S_ISDIR(stat_buf.st_mode)) {
	246
	247	printf("Entering channel subdirectory...\n");
	248	ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs);
	249	if(ret < 0) continue;
90ccaa9a	250	} else if(S_ISREG(stat_buf.st_mode)) {
	251	printf("Opening file.\n");
	252
	253	fd_pairs->pair = realloc(fd_pairs->pair,
	254	++fd_pairs->num_pairs * sizeof(struct fd_pair));
	255
	256	/* Open the channel in read mode */
	257	fd_pairs->pair[fd_pairs->num_pairs-1].channel =
	258	open(path_channel, O_RDONLY \| O_NONBLOCK);
	259	if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
	260	perror(path_channel);
469206ed	261	fd_pairs->num_pairs--;
469206ed	262	continue;
90ccaa9a	263	}
	264	/* Open the trace in write mode, only append if append_mode */
	265	ret = stat(path_trace, &stat_buf);
	266	if(ret == 0) {
	267	if(append_mode) {
3357d360	268	printf("Appending to file %s as requested\n", path_trace);
90ccaa9a	269
	270	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	271	open(path_trace, O_WRONLY\|O_APPEND,
	272	S_IRWXU\|S_IRWXG\|S_IRWXO);
	273
	274	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	275	perror(path_trace);
	276	}
	277	} else {
	278	printf("File %s exists, cannot open. Try append mode.\n", path_trace);
	279	return -1;
	280	}
	281	} else {
	282	if(errno == ENOENT) {
	283	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	284	open(path_trace, O_WRONLY\|O_CREAT\|O_EXCL,
	285	S_IRWXU\|S_IRWXG\|S_IRWXO);
	286	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	287	perror(path_trace);
	288	}
	289	}
	290	}
617de8e1	291	}
617de8e1	292	}
	293
	294	closedir(channel_dir);
	295
	296	return 0;
	297	}
	298
1d483eea	299
	300	int read_subbuffer(struct fd_pair *pair)
	301	{
	302	unsigned int subbuf_index;
469206ed	303	int err, ret;
1d483eea	304
1d483eea	305
469206ed	306	err = ioctl(pair->channel, RELAYFS_GET_SUBBUF,
1d483eea	307	&subbuf_index);
469206ed	308	printf("index : %u\n", subbuf_index);
469206ed	309	if(err != 0) {
1d483eea	310	perror("Error in reserving sub buffer");
469206ed	311	ret = -EPERM;
469206ed	312	goto get_error;
1d483eea	313	}
469206ed	314
469206ed	315	err = TEMP_FAILURE_RETRY(write(pair->trace,
1d483eea	316	pair->mmap + (subbuf_index * pair->subbuf_size),
1d483eea	317	pair->subbuf_size));
469206ed	318
469206ed	319	if(err < 0) {
1d483eea	320	perror("Error in writing to file");
469206ed	321	ret = err;
469206ed	322	goto write_error;
1d483eea	323	}
	324
	325
469206ed	326	write_error:
	327	err = ioctl(pair->channel, RELAYFS_PUT_SUBBUF);
	328	if(err != 0) {
1d483eea	329	perror("Error in unreserving sub buffer");
469206ed	330	ret = -EPERM;
469206ed	331	goto get_error;
1d483eea	332	}
1d483eea	333
469206ed	334	get_error:
469206ed	335	return ret;
1d483eea	336	}
	337
	338
90ccaa9a	339	/* read_channels
	340	*
	341	* Read the realyfs channels and write them in the paired tracefiles.
	342	*
	343	* @fd_pairs : paired channels and trace files.
	344	*
	345	* returns 0 on success, -1 on error.
	346	*
	347	* Note that the high priority polled channels are consumed first. We then poll
	348	* again to see if these channels are still in priority. Only when no
	349	* high priority channel is left, we start reading low priority channels.
	350	*
	351	* Note that a channel is considered high priority when the buffer is almost
	352	* full.
	353	*/
617de8e1	354
	355	int read_channels(struct channel_trace_fd *fd_pairs)
	356	{
90ccaa9a	357	struct pollfd *pollfd;
1d483eea	358	int i,j;
1d483eea	359	int num_rdy, num_hup;
4f45ea55	360	int high_prio;
1d483eea	361	int ret;
1d483eea	362
469206ed	363	if(fd_pairs->num_pairs <= 0) {
	364	printf("No channel to read\n");
	365	goto end;
	366	}
	367
1d483eea	368	/* Get the subbuf sizes and number */
	369
	370	for(i=0;i<fd_pairs->num_pairs;i++) {
	371	struct fd_pair *pair = &fd_pairs->pair[i];
90ccaa9a	372
1d483eea	373	ret = ioctl(pair->channel, RELAYFS_GET_N_SUBBUFS,
	374	&pair->n_subbufs);
	375	if(ret != 0) {
	376	perror("Error in getting the number of subbuffers");
	377	goto end;
	378	}
	379	ret = ioctl(pair->channel, RELAYFS_GET_SUBBUF_SIZE,
	380	&pair->subbuf_size);
	381	if(ret != 0) {
	382	perror("Error in getting the size of the subbuffers");
	383	goto end;
	384	}
	385	}
	386
	387	/* Mmap each FD */
	388	for(i=0;i<fd_pairs->num_pairs;i++) {
	389	struct fd_pair *pair = &fd_pairs->pair[i];
	390
	391	pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs, PROT_READ,
	392	MAP_SHARED, pair->channel, 0);
	393	if(pair->mmap == MAP_FAILED) {
	394	perror("Mmap error");
	395	goto munmap;
	396	}
	397	}
	398
	399
	400	/* Start polling the FD */
	401
90ccaa9a	402	pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd));
90ccaa9a	403
1d483eea	404	/* Note : index in pollfd is the same index as fd_pair->pair */
90ccaa9a	405	for(i=0;i<fd_pairs->num_pairs;i++) {
	406	pollfd[i].fd = fd_pairs->pair[i].channel;
	407	pollfd[i].events = POLLIN\|POLLPRI;
	408	}
	409
469206ed	410	/* Signal the parent that ready for IO */
	411	if(sig_parent) kill(getppid(), SIGIO);
	412
90ccaa9a	413	while(1) {
4f45ea55	414	high_prio = 0;
1d483eea	415	num_hup = 0;
	416	#ifdef DEBUG
	417	printf("Press a key for next poll...\n");
	418	char buf[1];
	419	read(STDIN_FILENO, &buf, 1);
469206ed	420	printf("Next poll (polling %d fd) :\n", fd_pairs->num_pairs);
1d483eea	421	#endif //DEBUG
	422
	423	/* Have we received a signal ? */
	424	if(quit_program) break;
	425
90ccaa9a	426	num_rdy = poll(pollfd, fd_pairs->num_pairs, -1);
	427	if(num_rdy == -1) {
	428	perror("Poll error");
1d483eea	429	goto free_fd;
90ccaa9a	430	}
	431
	432	printf("Data received\n");
	433
	434	for(i=0;i<fd_pairs->num_pairs;i++) {
	435	switch(pollfd[i].revents) {
	436	case POLLERR:
	437	printf("Error returned in polling fd %d.\n", pollfd[i].fd);
1d483eea	438	num_hup++;
90ccaa9a	439	break;
	440	case POLLHUP:
	441	printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd);
1d483eea	442	num_hup++;
90ccaa9a	443	break;
	444	case POLLNVAL:
	445	printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd);
1d483eea	446	num_hup++;
90ccaa9a	447	break;
90ccaa9a	448	case POLLPRI:
1d483eea	449	printf("Urgent read on fd %d\n", pollfd[i].fd);
90ccaa9a	450	/* Take care of high priority channels first. */
4f45ea55	451	high_prio = 1;
1d483eea	452	ret \|= read_subbuffer(&fd_pairs->pair[i]);
90ccaa9a	453	break;
4f45ea55	454	}
90ccaa9a	455	}
1d483eea	456	/* If every FD has hung up, we end the read loop here */
1d483eea	457	if(num_hup == fd_pairs->num_pairs) break;
90ccaa9a	458
4f45ea55	459	if(!high_prio) {
	460	for(i=0;i<fd_pairs->num_pairs;i++) {
	461	switch(pollfd[i].revents) {
	462	case POLLIN:
	463	/* Take care of low priority channels. */
1d483eea	464	printf("Normal read on fd %d\n", pollfd[i].fd);
1d483eea	465	ret \|= read_subbuffer(&fd_pairs->pair[i]);
4f45ea55	466	break;
	467	}
	468	}
90ccaa9a	469	}
	470
	471	}
	472
1d483eea	473	free_fd:
90ccaa9a	474	free(pollfd);
90ccaa9a	475
1d483eea	476	/* munmap only the successfully mmapped indexes */
	477	i = fd_pairs->num_pairs;
	478	munmap:
	479	/* Munmap each FD */
	480	for(j=0;j<i;j++) {
	481	struct fd_pair *pair = &fd_pairs->pair[j];
	482	int err_ret;
	483
	484	err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
	485	if(err_ret != 0) {
	486	perror("Error in munmap");
	487	}
	488	ret \|= err_ret;
	489	}
	490
	491	end:
	492	return ret;
617de8e1	493	}
	494
	495
	496	void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs)
	497	{
90ccaa9a	498	int i;
90ccaa9a	499	int ret;
617de8e1	500
90ccaa9a	501	for(i=0;i<fd_pairs->num_pairs;i++) {
	502	ret = close(fd_pairs->pair[i].channel);
	503	if(ret == -1) perror("Close error on channel");
	504	ret = close(fd_pairs->pair[i].trace);
	505	if(ret == -1) perror("Close error on trace");
	506	}
	507	free(fd_pairs->pair);
617de8e1	508	}
	509
	510	int main(int argc, char ** argv)
	511	{
	512	int ret;
	513	pid_t pid;
	514	struct channel_trace_fd fd_pairs = { NULL, 0 };
1d483eea	515	struct sigaction act;
617de8e1	516
	517	ret = parse_arguments(argc, argv);
	518
	519	if(ret != 0) show_arguments();
	520	if(ret < 0) return EINVAL;
	521	if(ret > 0) return 0;
	522
	523	show_info();
	524
	525	if(daemon_mode) {
	526	pid = fork();
	527
	528	if(pid > 0) {
	529	/* parent */
	530	return 0;
	531	} else if(pid < 0) {
	532	/* error */
	533	printf("An error occured while forking.\n");
	534	return -1;
	535	}
	536	/* else, we are the child, continue... */
	537	}
	538
1d483eea	539	/* Connect the signal handlers */
	540	act.sa_handler = handler;
	541	act.sa_flags = 0;
	542	sigemptyset(&(act.sa_mask));
	543	sigaddset(&(act.sa_mask), SIGTERM);
	544	sigaddset(&(act.sa_mask), SIGQUIT);
	545	sigaddset(&(act.sa_mask), SIGINT);
	546	sigaction(SIGTERM, &act, NULL);
	547	sigaction(SIGQUIT, &act, NULL);
	548	sigaction(SIGINT, &act, NULL);
	549
	550	//return 0;
617de8e1	551	if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs))
90ccaa9a	552	goto close_channel;
617de8e1	553
	554	ret = read_channels(&fd_pairs);
	555
90ccaa9a	556	close_channel:
617de8e1	557	close_channel_trace_pairs(&fd_pairs);
617de8e1	558
617de8e1	559	return ret;
617de8e1	560	}