[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>
 */

#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <dirent.h>
#include <string.h>
#include <fcntl.h>
#include <sys/poll.h>

enum {
	GET_SUBBUF,
	PUT_SUBBUF,
	GET_N_BUBBUFS,
	GET_SUBBUF_SIZE
};

struct fd_pair {
	int channel;
	int trace;
};

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;

/* 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");
}


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;
}

/* 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;
	int num_rdy;
	int high_prio;

	pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd));

	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_rdy = poll(pollfd, fd_pairs->num_pairs, -1);
		if(num_rdy == -1) {
			perror("Poll error");
			return -1;
		}

		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);
					break;
				case POLLHUP:
					printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd);
					break;
				case POLLNVAL:
					printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd);
					break;
				case POLLPRI:
					/* Take care of high priority channels first. */
					high_prio = 1;
					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. */
						break;
				}
			}
		}

	}

	free(pollfd);

	return 0;
}


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 };
	
	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... */
	}

	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
	13	#include <stdio.h>
	14	#include <errno.h>
	15	#include <sys/types.h>
	16	#include <sys/stat.h>
	17	#include <unistd.h>
	18	#include <stdlib.h>
	19	#include <dirent.h>
	20	#include <string.h>
90ccaa9a	21	#include <fcntl.h>
90ccaa9a	22	#include <sys/poll.h>
617de8e1	23
	24	enum {
	25	GET_SUBBUF,
	26	PUT_SUBBUF,
	27	GET_N_BUBBUFS,
	28	GET_SUBBUF_SIZE
	29	};
	30
	31	struct fd_pair {
	32	int channel;
	33	int trace;
	34	};
	35
	36	struct channel_trace_fd {
	37	struct fd_pair *pair;
	38	int num_pairs;
	39	};
	40
	41	static char *trace_name = NULL;
	42	static char *channel_name = NULL;
	43	static int daemon_mode = 0;
90ccaa9a	44	static int append_mode = 0;
617de8e1	45
	46	/* Args :
	47	*
	48	* -t directory Directory name of the trace to write to. Will be created.
	49	* -c directory Root directory of the relayfs trace channels.
	50	* -d Run in background (daemon).
90ccaa9a	51	* -a Trace append mode.
617de8e1	52	*/
	53	void show_arguments(void)
	54	{
	55	printf("Please use the following arguments :\n");
	56	printf("\n");
	57	printf("-t directory Directory name of the trace to write to.\n"
	58	" It will be created.\n");
	59	printf("-c directory Root directory of the relayfs trace channels.\n");
	60	printf("-d Run in background (daemon).\n");
90ccaa9a	61	printf("-a Append to an possibly existing trace.\n");
617de8e1	62	printf("\n");
	63	}
	64
	65
	66	/* parse_arguments
	67	*
	68	* Parses the command line arguments.
	69	*
	70	* Returns 1 if the arguments were correct, but doesn't ask for program
	71	* continuation. Returns -1 if the arguments are incorrect, or 0 if OK.
	72	*/
	73	int parse_arguments(int argc, char **argv)
	74	{
	75	int ret = 0;
	76	int argn = 1;
	77
	78	if(argc == 2) {
	79	if(strcmp(argv[1], "-h") == 0) {
	80	return 1;
	81	}
	82	}
	83
90ccaa9a	84	while(argn < argc) {
617de8e1	85
	86	switch(argv[argn][0]) {
	87	case '-':
	88	switch(argv[argn][1]) {
	89	case 't':
90ccaa9a	90	if(argn+1 < argc) {
	91	trace_name = argv[argn+1];
	92	argn++;
	93	}
617de8e1	94	break;
617de8e1	95	case 'c':
90ccaa9a	96	if(argn+1 < argc) {
	97	channel_name = argv[argn+1];
	98	argn++;
	99	}
617de8e1	100	break;
	101	case 'd':
	102	daemon_mode = 1;
	103	break;
90ccaa9a	104	case 'a':
	105	append_mode = 1;
	106	break;
617de8e1	107	default:
	108	printf("Invalid argument '%s'.\n", argv[argn]);
	109	printf("\n");
	110	ret = -1;
	111	}
	112	break;
	113	default:
	114	printf("Invalid argument '%s'.\n", argv[argn]);
	115	printf("\n");
	116	ret = -1;
	117	}
	118	argn++;
	119	}
	120
	121	if(trace_name == NULL) {
	122	printf("Please specify a trace name.\n");
	123	printf("\n");
	124	ret = -1;
	125	}
	126
	127	if(channel_name == NULL) {
	128	printf("Please specify a channel name.\n");
	129	printf("\n");
	130	ret = -1;
	131	}
	132
	133	return ret;
	134	}
	135
	136	void show_info(void)
	137	{
	138	printf("Linux Trace Toolkit Trace Daemon\n");
	139	printf("\n");
	140	printf("Reading from relayfs directory : %s\n", channel_name);
	141	printf("Writing to trace directory : %s\n", trace_name);
	142	printf("\n");
	143	}
	144
	145
	146	int open_channel_trace_pairs(char subchannel_name, char subtrace_name,
	147	struct channel_trace_fd *fd_pairs)
	148	{
	149	DIR *channel_dir = opendir(subchannel_name);
	150	struct dirent *entry;
	151	struct stat stat_buf;
	152	int ret;
	153	char path_channel[PATH_MAX];
	154	int path_channel_len;
	155	char *path_channel_ptr;
	156	char path_trace[PATH_MAX];
	157	int path_trace_len;
	158	char *path_trace_ptr;
	159
	160	if(channel_dir == NULL) {
	161	perror(subchannel_name);
	162	return ENOENT;
	163	}
	164
	165	//FIXME : check if the directory already exist, and ask the user if he wants
	166	//to append to the traces.
	167	printf("Creating trace subdirectory %s\n", subtrace_name);
	168	ret = mkdir(subtrace_name, S_IRWXU\|S_IRWXG\|S_IRWXO);
	169	if(ret == -1) {
90ccaa9a	170	if(errno == EEXIST && append_mode) {
	171	printf("Appending to directory %s as resquested\n", subtrace_name);
	172	} else {
	173	perror(subtrace_name);
	174	return -1;
	175	}
617de8e1	176	}
	177
	178	strncpy(path_channel, subchannel_name, PATH_MAX-1);
	179	path_channel_len = strlen(path_channel);
	180	path_channel[path_channel_len] = '/';
	181	path_channel_len++;
	182	path_channel_ptr = path_channel + path_channel_len;
	183
	184	strncpy(path_trace, subtrace_name, PATH_MAX-1);
	185	path_trace_len = strlen(path_trace);
	186	path_trace[path_trace_len] = '/';
	187	path_trace_len++;
	188	path_trace_ptr = path_trace + path_trace_len;
	189
	190	while((entry = readdir(channel_dir)) != NULL) {
	191
	192	if(entry->d_name[0] == '.') continue;
	193
	194	strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
	195	strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len);
	196
	197	ret = stat(path_channel, &stat_buf);
	198	if(ret == -1) {
	199	perror(path_channel);
	200	continue;
	201	}
	202
	203	printf("Channel file : %s\n", path_channel);
	204
	205	if(S_ISDIR(stat_buf.st_mode)) {
	206
	207	printf("Entering channel subdirectory...\n");
	208	ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs);
	209	if(ret < 0) continue;
90ccaa9a	210	} else if(S_ISREG(stat_buf.st_mode)) {
	211	printf("Opening file.\n");
	212
	213	fd_pairs->pair = realloc(fd_pairs->pair,
	214	++fd_pairs->num_pairs * sizeof(struct fd_pair));
	215
	216	/* Open the channel in read mode */
	217	fd_pairs->pair[fd_pairs->num_pairs-1].channel =
	218	open(path_channel, O_RDONLY \| O_NONBLOCK);
	219	if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
	220	perror(path_channel);
	221	}
	222	/* Open the trace in write mode, only append if append_mode */
	223	ret = stat(path_trace, &stat_buf);
	224	if(ret == 0) {
	225	if(append_mode) {
	226	printf("Appending to file %s as resquested\n", path_trace);
	227
	228	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	229	open(path_trace, O_WRONLY\|O_APPEND,
	230	S_IRWXU\|S_IRWXG\|S_IRWXO);
	231
	232	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	233	perror(path_trace);
	234	}
	235	} else {
	236	printf("File %s exists, cannot open. Try append mode.\n", path_trace);
	237	return -1;
	238	}
	239	} else {
	240	if(errno == ENOENT) {
	241	fd_pairs->pair[fd_pairs->num_pairs-1].trace =
	242	open(path_trace, O_WRONLY\|O_CREAT\|O_EXCL,
	243	S_IRWXU\|S_IRWXG\|S_IRWXO);
	244	if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
	245	perror(path_trace);
	246	}
	247	}
	248	}
617de8e1	249	}
617de8e1	250	}
	251
	252	closedir(channel_dir);
	253
	254	return 0;
	255	}
	256
90ccaa9a	257	/* read_channels
	258	*
	259	* Read the realyfs channels and write them in the paired tracefiles.
	260	*
	261	* @fd_pairs : paired channels and trace files.
	262	*
	263	* returns 0 on success, -1 on error.
	264	*
	265	* Note that the high priority polled channels are consumed first. We then poll
	266	* again to see if these channels are still in priority. Only when no
	267	* high priority channel is left, we start reading low priority channels.
	268	*
	269	* Note that a channel is considered high priority when the buffer is almost
	270	* full.
	271	*/
617de8e1	272
	273	int read_channels(struct channel_trace_fd *fd_pairs)
	274	{
90ccaa9a	275	struct pollfd *pollfd;
	276	int i;
	277	int num_rdy;
4f45ea55	278	int high_prio;
90ccaa9a	279
	280	pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd));
	281
	282	for(i=0;i<fd_pairs->num_pairs;i++) {
	283	pollfd[i].fd = fd_pairs->pair[i].channel;
	284	pollfd[i].events = POLLIN\|POLLPRI;
	285	}
	286
	287	while(1) {
4f45ea55	288	high_prio = 0;
4f45ea55	289
90ccaa9a	290	num_rdy = poll(pollfd, fd_pairs->num_pairs, -1);
	291	if(num_rdy == -1) {
	292	perror("Poll error");
	293	return -1;
	294	}
	295
	296	printf("Data received\n");
	297
	298	for(i=0;i<fd_pairs->num_pairs;i++) {
	299	switch(pollfd[i].revents) {
	300	case POLLERR:
	301	printf("Error returned in polling fd %d.\n", pollfd[i].fd);
	302	break;
	303	case POLLHUP:
	304	printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd);
	305	break;
	306	case POLLNVAL:
	307	printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd);
	308	break;
	309	case POLLPRI:
	310	/* Take care of high priority channels first. */
4f45ea55	311	high_prio = 1;
90ccaa9a	312	break;
4f45ea55	313	}
90ccaa9a	314	}
90ccaa9a	315
4f45ea55	316	if(!high_prio) {
	317	for(i=0;i<fd_pairs->num_pairs;i++) {
	318	switch(pollfd[i].revents) {
	319	case POLLIN:
	320	/* Take care of low priority channels. */
	321	break;
	322	}
	323	}
90ccaa9a	324	}
	325
	326	}
	327
	328	free(pollfd);
	329
617de8e1	330	return 0;
	331	}
	332
	333
	334	void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs)
	335	{
90ccaa9a	336	int i;
90ccaa9a	337	int ret;
617de8e1	338
90ccaa9a	339	for(i=0;i<fd_pairs->num_pairs;i++) {
	340	ret = close(fd_pairs->pair[i].channel);
	341	if(ret == -1) perror("Close error on channel");
	342	ret = close(fd_pairs->pair[i].trace);
	343	if(ret == -1) perror("Close error on trace");
	344	}
	345	free(fd_pairs->pair);
617de8e1	346	}
	347
	348	int main(int argc, char ** argv)
	349	{
	350	int ret;
	351	pid_t pid;
	352	struct channel_trace_fd fd_pairs = { NULL, 0 };
	353
	354	ret = parse_arguments(argc, argv);
	355
	356	if(ret != 0) show_arguments();
	357	if(ret < 0) return EINVAL;
	358	if(ret > 0) return 0;
	359
	360	show_info();
	361
	362	if(daemon_mode) {
	363	pid = fork();
	364
	365	if(pid > 0) {
	366	/* parent */
	367	return 0;
	368	} else if(pid < 0) {
	369	/* error */
	370	printf("An error occured while forking.\n");
	371	return -1;
	372	}
	373	/* else, we are the child, continue... */
	374	}
	375
	376	if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs))
90ccaa9a	377	goto close_channel;
617de8e1	378
	379	ret = read_channels(&fd_pairs);
	380
90ccaa9a	381	close_channel:
617de8e1	382	close_channel_trace_pairs(&fd_pairs);
617de8e1	383
617de8e1	384	return ret;
617de8e1	385	}