[khatus.git] / x5 / khatus.c


#include <fcntl.h>
#include <unistd.h>
#include <sys/select.h>
#include <sys/stat.h>

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define debug(args...) {fprintf(stderr, "[debug] " args);}
#define info( args...) {fprintf(stderr, "[info] "  args);}
#define error(args...) {fprintf(stderr, "[error] " args);}
#define fatal(args...) {fprintf(stderr, "[fatal] " args); exit(EXIT_FAILURE);}
#define usage(args...) {print_usage(); fatal("[usage] " args);}

char *argv0;

typedef struct File File;
struct File {
	char   *name;
	int     fd;
	int     width;
	int     last_read;
	int     ttl;
	int     pos;  /* Position on the output buffer. */
	File   *next;
};

typedef struct Config Config;
struct Config {
	int    interval;
	char * separator;
	File * files;
	int    file_count;
	int    total_width;
} defaults = {
	.interval    = 1,
	.separator   = "|",
	.files       = NULL,
	.file_count  = 0,
	.total_width = 0,
};

void
file_print_one(File *f)
{
	debug(
		"File "
		"{"
			" name = %s,"
			" fd = %d,"
			" width = %d,"
			" last_read = %d,"
			" ttl = %d,"
			" pos = %d,"
			" next = %p,"
		" }\n",
		f->name,
		f->fd,
		f->width,
		f->last_read,
		f->ttl,
		f->pos,
		f->next
	);
}

void
file_print_all(File *head)
{
	for (File *f = head; f; f = f->next) {
		file_print_one(f);
	}
}

void
config_print(Config *c)
{
	debug(
		"Config "
		"{"
			" interval = %d,"
			" separator = %s,"
			" file_count = %d,"
			" total_width = %d,"
			" files = ..."
		" }\n",
		c->interval,
		c->separator,
		c->file_count,
		c->total_width
	);
	file_print_all(c->files);
}

int
is_pos_num(char *s)
{
	while (*s != '\0')
		if (!isdigit(*(s++)))
			return 0;
	return 1;
}

void
print_usage()
{
	assert(argv0);
	fprintf(
		stderr,
		"\n"
		"Usage: %s [OPTION ...] SPEC [SPEC ...]\n"
		"\n"
		"  SPEC       = FILE_PATH DATA_WIDTH DATA_TTL\n"
		"  FILE_PATH  = string\n"
		"  DATA_WIDTH = int  (* (positive) number of characters *)\n"
		"  DATA_TTL   = int  (* (positive) number of seconds *)\n"
		"  OPTION     = -i INTERVAL\n"
		"             | -s SEPARATOR\n"
		"  SEPARATOR  = string\n"
		"  INTERVAL   = int  (* (positive) number of seconds *)\n"
		"\n",
		argv0
	);
	fprintf(
		stderr,
		"Example: %s -i 1 /dev/shm/khatus/khatus_sensor_x 4 10\n"
		"\n",
		argv0
	);
}

void opts_parse_any(Config *, int, char *[], int);  /* For mutually-recursive calls. */

void
parse_opts_opt_i(Config *cfg, int argc, char *argv[], int i)
{
	if (i < argc) {
		char *param = argv[i++];

		if (is_pos_num(param)) {
			cfg->interval = atoi(param);
			opts_parse_any(cfg, argc, argv, i);
		} else {
			usage("Option -i parameter is invalid: \"%s\"\n", param);
		}
	} else {
		usage("Option -i parameter is missing.\n");
	}
}

void
parse_opts_opt_s(Config *cfg, int argc, char *argv[], int i)
{
	if (i < argc) {
		cfg->separator = calloc((strlen(argv[i]) + 1), sizeof(char));
		strcpy(cfg->separator, argv[i]);
		opts_parse_any(cfg, argc, argv, ++i);
	} else {
		usage("Option -s parameter is missing.\n");
	}
}

void
parse_opts_opt(Config *cfg, int argc, char *argv[], int i)
{
	switch (argv[i][1]) {
		case 'i': parse_opts_opt_i(cfg, argc, argv, ++i); break;  /* TODO: Generic set_int */
		case 's': parse_opts_opt_s(cfg, argc, argv, ++i); break;  /* TODO: Generic set_str */
		default : usage("Option \"%s\" is invalid\n", argv[i]);
	}
}

void
parse_opts_spec(Config *cfg, int argc, char *argv[], int i)
{
	if ((i + 3) > argc)
		usage("[spec] Parameter(s) missing for file \"%s\".\n", argv[i]);

	char *n = argv[i++];
	char *w = argv[i++];
	char *t = argv[i++];

	if (!is_pos_num(w))
		usage("[spec] Invalid width: \"%s\", for file \"%s\"\n", w, n);
	if (!is_pos_num(t))
		usage("[spec] Invalid TTL: \"%s\", for file \"%s\"\n", t, n);
	File *f = calloc(1, sizeof(struct File));
	if (f) {
		f->name      = n;
		f->fd        = -1;
		f->width     = atoi(w);
		f->ttl       = atoi(t);
		f->last_read = 0;
		f->pos       = cfg->total_width;
		f->next      = cfg->files;

		cfg->files        = f;
		cfg->total_width += f->width;
		cfg->file_count++;
	} else {
		fatal("[memory] Allocation failure.");
	}
	opts_parse_any(cfg, argc, argv, i);
}

void
opts_parse_any(Config *cfg, int argc, char *argv[], int i)
{
	if (i < argc) {
		switch (argv[i][0]) {
			case '-': parse_opts_opt(cfg, argc, argv, i); break;
			default : parse_opts_spec(cfg, argc, argv, i);
		}
	}
}

void
opts_parse(Config *cfg, int argc, char *argv[], int i)
{
	opts_parse_any(cfg, argc, argv, 1);

	File *last = cfg->files;
	cfg->files = NULL;
	for (File *f = last; f; ) {
		File *next = f->next;
		f->next = cfg->files;
		cfg->files = f;
		f = next;
	}
}

void
read_one(File *f, char *buf)
{
	ssize_t n;
	char *b;

	b = buf + f->pos;
	memset(b, ' ', f->width);
	/* TODO: Read upto \n or width */
	while ((n = read(f->fd, b, f->width)) > 0) {
		b += n;
		debug("read %zd from %s\n", n, f->name);
	}

	if (n > -1) {
		if (*(b - 1) == '\n')
			*(b - 1) = ' ';
	} else {
		error(
			"Failed to read: \"%s\". Error: %s\n",
			f->name,
			strerror(errno)
		);
	}

	close(f->fd);
	f->fd = -1;
}

void
read_all(Config *cfg, char *buf)
{
	fd_set fds;
	int maxfd;
	int ready;
	struct stat st;

	FD_ZERO(&fds);

	/* TODO: Check TTL */
	for (File *f = cfg->files; f; f = f->next) {
		/* TODO: Create the FIFO if it doesn't already exist. */
		if (lstat(f->name, &st) < 0)
			fatal("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
		if (!(st.st_mode & S_IFIFO))
			fatal("\"%s\" is not a FIFO\n", f->name);
		debug("opening: %s\n", f->name);
		if (f->fd < 0)
			f->fd = open(f->name, O_RDONLY | O_NONBLOCK);
		if (f->fd == -1)
			/* TODO: Consider backing off retries for failed files. */
			fatal("Failed to open \"%s\"\n", f->name);
		if (f->fd > maxfd)
			maxfd = f->fd;
		FD_SET(f->fd, &fds);
	}
	debug("selecting...\n");
	ready = select(maxfd + 1, &fds, NULL, NULL, NULL);
	debug("ready: %d\n", ready);
	assert(ready != 0);
	if (ready < 0)
		fatal("%s", strerror(errno));
	for (File *f = cfg->files; f; f = f->next) {
		if (FD_ISSET(f->fd, &fds)) {
			debug("reading: %s\n", f->name);
			read_one(f, buf);
		}
	}
}

int
main(int argc, char *argv[])
{
	int width;
	int nfiles = 0;
	int seplen;
	int prefix = 0;
	char *buf;
	Config *cfg = &defaults;

	argv0 = argv[0];

	opts_parse(cfg, argc, argv, 1);
	debug("argv0 = %s\n", argv0);
	config_print(cfg);
	if (cfg->files == NULL)
		usage("No file specs were given!\n");

	width  = cfg->total_width;
	seplen = strlen(cfg->separator);

	/* 1st pass to make space for separators */
	for (File *f = cfg->files; f; f = f->next) {
		f->pos += prefix;
		prefix += seplen;
		nfiles++;
	}
	width += (seplen * (nfiles - 1));
	buf = calloc(1, width + 1);
	if (buf == NULL)
		fatal("[memory] Failed to allocate buffer of %d bytes", width);
	memset(buf, ' ', width);
	buf[width] = '\0';
	/* 2nd pass to set the separators */
	for (File *f = cfg->files; f; f = f->next) {
		if (f->pos) {  /* Skip the first, left-most */
			/* Copying only seplen ensures we omit the '\0' byte. */
			strncpy(buf + (f->pos - seplen), cfg->separator, seplen);
		}
	}

	printf("%s\n", buf);
	/* TODO: nanosleep and nano time diff */
	for (;;) {
		read_all(cfg, buf);
		printf("%s\n", buf);
	}
}
Commit	Line	Data
	1
	2	#include <fcntl.h>
	3	#include <unistd.h>
	4	#include <sys/select.h>
	5	#include <sys/stat.h>
	6
	7	#include <assert.h>
	8	#include <ctype.h>
	9	#include <errno.h>
	10	#include <stdio.h>
	11	#include <stdlib.h>
	12	#include <string.h>
	13
	14	#define debug(args...) {fprintf(stderr, "[debug] " args);}
	15	#define info( args...) {fprintf(stderr, "[info] " args);}
	16	#define error(args...) {fprintf(stderr, "[error] " args);}
	17	#define fatal(args...) {fprintf(stderr, "[fatal] " args); exit(EXIT_FAILURE);}
	18	#define usage(args...) {print_usage(); fatal("[usage] " args);}
	19
	20	char *argv0;
	21
	22	typedef struct File File;
	23	struct File {
	24	char *name;
	25	int fd;
	26	int width;
	27	int last_read;
	28	int ttl;
	29	int pos; /* Position on the output buffer. */
	30	File *next;
	31	};
	32
	33	typedef struct Config Config;
	34	struct Config {
	35	int interval;
	36	char * separator;
	37	File * files;
	38	int file_count;
	39	int total_width;
	40	} defaults = {
	41	.interval = 1,
	42	.separator = "\|",
	43	.files = NULL,
	44	.file_count = 0,
	45	.total_width = 0,
	46	};
	47
	48	void
	49	file_print_one(File *f)
	50	{
	51	debug(
	52	"File "
	53	"{"
	54	" name = %s,"
	55	" fd = %d,"
	56	" width = %d,"
	57	" last_read = %d,"
	58	" ttl = %d,"
	59	" pos = %d,"
	60	" next = %p,"
	61	" }\n",
	62	f->name,
	63	f->fd,
	64	f->width,
	65	f->last_read,
	66	f->ttl,
	67	f->pos,
	68	f->next
	69	);
	70	}
	71
	72	void
	73	file_print_all(File *head)
	74	{
	75	for (File *f = head; f; f = f->next) {
	76	file_print_one(f);
	77	}
	78	}
	79
	80	void
	81	config_print(Config *c)
	82	{
	83	debug(
	84	"Config "
	85	"{"
	86	" interval = %d,"
	87	" separator = %s,"
	88	" file_count = %d,"
	89	" total_width = %d,"
	90	" files = ..."
	91	" }\n",
	92	c->interval,
	93	c->separator,
	94	c->file_count,
	95	c->total_width
	96	);
	97	file_print_all(c->files);
	98	}
	99
	100	int
	101	is_pos_num(char *s)
	102	{
	103	while (*s != '\0')
	104	if (!isdigit(*(s++)))
	105	return 0;
	106	return 1;
	107	}
	108
	109	void
	110	print_usage()
	111	{
	112	assert(argv0);
	113	fprintf(
	114	stderr,
	115	"\n"
	116	"Usage: %s [OPTION ...] SPEC [SPEC ...]\n"
	117	"\n"
	118	" SPEC = FILE_PATH DATA_WIDTH DATA_TTL\n"
	119	" FILE_PATH = string\n"
	120	" DATA_WIDTH = int (* (positive) number of characters *)\n"
	121	" DATA_TTL = int (* (positive) number of seconds *)\n"
	122	" OPTION = -i INTERVAL\n"
	123	" \| -s SEPARATOR\n"
	124	" SEPARATOR = string\n"
	125	" INTERVAL = int (* (positive) number of seconds *)\n"
	126	"\n",
	127	argv0
	128	);
	129	fprintf(
	130	stderr,
	131	"Example: %s -i 1 /dev/shm/khatus/khatus_sensor_x 4 10\n"
	132	"\n",
	133	argv0
	134	);
	135	}
	136
	137	void opts_parse_any(Config , int, char [], int); /* For mutually-recursive calls. */
	138
	139	void
	140	parse_opts_opt_i(Config cfg, int argc, char argv[], int i)
	141	{
	142	if (i < argc) {
	143	char *param = argv[i++];
	144
	145	if (is_pos_num(param)) {
	146	cfg->interval = atoi(param);
	147	opts_parse_any(cfg, argc, argv, i);
	148	} else {
	149	usage("Option -i parameter is invalid: \"%s\"\n", param);
	150	}
	151	} else {
	152	usage("Option -i parameter is missing.\n");
	153	}
	154	}
	155
	156	void
	157	parse_opts_opt_s(Config cfg, int argc, char argv[], int i)
	158	{
	159	if (i < argc) {
	160	cfg->separator = calloc((strlen(argv[i]) + 1), sizeof(char));
	161	strcpy(cfg->separator, argv[i]);
	162	opts_parse_any(cfg, argc, argv, ++i);
	163	} else {
	164	usage("Option -s parameter is missing.\n");
	165	}
	166	}
	167
	168	void
	169	parse_opts_opt(Config cfg, int argc, char argv[], int i)
	170	{
	171	switch (argv[i][1]) {
	172	case 'i': parse_opts_opt_i(cfg, argc, argv, ++i); break; /* TODO: Generic set_int */
	173	case 's': parse_opts_opt_s(cfg, argc, argv, ++i); break; /* TODO: Generic set_str */
	174	default : usage("Option \"%s\" is invalid\n", argv[i]);
	175	}
	176	}
	177
	178	void
	179	parse_opts_spec(Config cfg, int argc, char argv[], int i)
	180	{
	181	if ((i + 3) > argc)
	182	usage("[spec] Parameter(s) missing for file \"%s\".\n", argv[i]);
	183
	184	char *n = argv[i++];
	185	char *w = argv[i++];
	186	char *t = argv[i++];
	187
	188	if (!is_pos_num(w))
	189	usage("[spec] Invalid width: \"%s\", for file \"%s\"\n", w, n);
	190	if (!is_pos_num(t))
	191	usage("[spec] Invalid TTL: \"%s\", for file \"%s\"\n", t, n);
	192	File *f = calloc(1, sizeof(struct File));
	193	if (f) {
	194	f->name = n;
	195	f->fd = -1;
	196	f->width = atoi(w);
	197	f->ttl = atoi(t);
	198	f->last_read = 0;
	199	f->pos = cfg->total_width;
	200	f->next = cfg->files;
	201
	202	cfg->files = f;
	203	cfg->total_width += f->width;
	204	cfg->file_count++;
	205	} else {
	206	fatal("[memory] Allocation failure.");
	207	}
	208	opts_parse_any(cfg, argc, argv, i);
	209	}
	210
	211	void
	212	opts_parse_any(Config cfg, int argc, char argv[], int i)
	213	{
	214	if (i < argc) {
	215	switch (argv[i][0]) {
	216	case '-': parse_opts_opt(cfg, argc, argv, i); break;
	217	default : parse_opts_spec(cfg, argc, argv, i);
	218	}
	219	}
	220	}
	221
	222	void
	223	opts_parse(Config cfg, int argc, char argv[], int i)
	224	{
	225	opts_parse_any(cfg, argc, argv, 1);
	226
	227	File *last = cfg->files;
	228	cfg->files = NULL;
	229	for (File *f = last; f; ) {
	230	File *next = f->next;
	231	f->next = cfg->files;
	232	cfg->files = f;
	233	f = next;
	234	}
	235	}
	236
	237	void
	238	read_one(File f, char buf)
	239	{
	240	ssize_t n;
	241	char *b;
	242
	243	b = buf + f->pos;
	244	memset(b, ' ', f->width);
	245	/* TODO: Read upto \n or width */
	246	while ((n = read(f->fd, b, f->width)) > 0) {
	247	b += n;
	248	debug("read %zd from %s\n", n, f->name);
	249	}
	250
	251	if (n > -1) {
	252	if (*(b - 1) == '\n')
	253	*(b - 1) = ' ';
	254	} else {
	255	error(
	256	"Failed to read: \"%s\". Error: %s\n",
	257	f->name,
	258	strerror(errno)
	259	);
	260	}
	261
	262	close(f->fd);
	263	f->fd = -1;
	264	}
	265
	266	void
	267	read_all(Config cfg, char buf)
	268	{
	269	fd_set fds;
	270	int maxfd;
	271	int ready;
	272	struct stat st;
	273
	274	FD_ZERO(&fds);
	275
	276	/* TODO: Check TTL */
	277	for (File *f = cfg->files; f; f = f->next) {
	278	/* TODO: Create the FIFO if it doesn't already exist. */
	279	if (lstat(f->name, &st) < 0)
	280	fatal("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
	281	if (!(st.st_mode & S_IFIFO))
	282	fatal("\"%s\" is not a FIFO\n", f->name);
	283	debug("opening: %s\n", f->name);
	284	if (f->fd < 0)
	285	f->fd = open(f->name, O_RDONLY \| O_NONBLOCK);
	286	if (f->fd == -1)
	287	/* TODO: Consider backing off retries for failed files. */
	288	fatal("Failed to open \"%s\"\n", f->name);
	289	if (f->fd > maxfd)
	290	maxfd = f->fd;
	291	FD_SET(f->fd, &fds);
	292	}
	293	debug("selecting...\n");
	294	ready = select(maxfd + 1, &fds, NULL, NULL, NULL);
	295	debug("ready: %d\n", ready);
	296	assert(ready != 0);
	297	if (ready < 0)
	298	fatal("%s", strerror(errno));
	299	for (File *f = cfg->files; f; f = f->next) {
	300	if (FD_ISSET(f->fd, &fds)) {
	301	debug("reading: %s\n", f->name);
	302	read_one(f, buf);
	303	}
	304	}
	305	}
	306
	307	int
	308	main(int argc, char *argv[])
	309	{
	310	int width;
	311	int nfiles = 0;
	312	int seplen;
	313	int prefix = 0;
	314	char *buf;
	315	Config *cfg = &defaults;
	316
	317	argv0 = argv[0];
	318
	319	opts_parse(cfg, argc, argv, 1);
	320	debug("argv0 = %s\n", argv0);
	321	config_print(cfg);
	322	if (cfg->files == NULL)
	323	usage("No file specs were given!\n");
	324
	325	width = cfg->total_width;
	326	seplen = strlen(cfg->separator);
	327
	328	/* 1st pass to make space for separators */
	329	for (File *f = cfg->files; f; f = f->next) {
	330	f->pos += prefix;
	331	prefix += seplen;
	332	nfiles++;
	333	}
	334	width += (seplen * (nfiles - 1));
	335	buf = calloc(1, width + 1);
	336	if (buf == NULL)
	337	fatal("[memory] Failed to allocate buffer of %d bytes", width);
	338	memset(buf, ' ', width);
	339	buf[width] = '\0';
	340	/* 2nd pass to set the separators */
	341	for (File *f = cfg->files; f; f = f->next) {
	342	if (f->pos) { /* Skip the first, left-most */
	343	/* Copying only seplen ensures we omit the '\0' byte. */
	344	strncpy(buf + (f->pos - seplen), cfg->separator, seplen);
	345	}
	346	}
	347
	348	printf("%s\n", buf);
	349	/* TODO: nanosleep and nano time diff */
	350	for (;;) {
	351	read_all(cfg, buf);
	352	printf("%s\n", buf);
	353	}
	354	}