[khatus.git] / x5 / khatus.c

#include <fcntl.h>
#include <unistd.h>
#include <sys/select.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);
	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;

	FD_ZERO(&fds);

	/* TODO: stat then check TTL */
	for (File *f = cfg->files; f; f = f->next) {
		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
77c76070 SK	1	#include <fcntl.h>
	2	#include <unistd.h>
	3	#include <sys/select.h>
4d66492f	4
9b5ebc12 SK	5	#include <assert.h>
9b5ebc12 SK	6	#include <ctype.h>
77c76070	7	#include <errno.h>
9b5ebc12 SK	8	#include <stdio.h>
	9	#include <stdlib.h>
	10	#include <string.h>
	11
4d66492f SK	12	#define debug(args...) {fprintf(stderr, "[debug] " args);}
	13	#define info( args...) {fprintf(stderr, "[info] " args);}
	14	#define error(args...) {fprintf(stderr, "[error] " args);}
	15	#define fatal(args...) {fprintf(stderr, "[fatal] " args); exit(EXIT_FAILURE);}
	16	#define usage(args...) {print_usage(); fatal("[usage] " args);}
9b5ebc12	17
4d66492f	18	char *argv0;
9b5ebc12	19
4d66492f SK	20	typedef struct File File;
	21	struct File {
	22	char *name;
	23	int fd;
9b5ebc12	24	int width;
4d66492f	25	int last_read;
9b5ebc12	26	int ttl;
4d66492f SK	27	int pos; /* Position on the output buffer. */
4d66492f SK	28	File *next;
9b5ebc12 SK	29	};
9b5ebc12 SK	30
4d66492f SK	31	typedef struct Config Config;
4d66492f SK	32	struct Config {
9b5ebc12	33	int interval;
4d66492f	34	char * separator;
4d66492f SK	35	File * files;
	36	int file_count;
	37	int total_width;
	38	} defaults = {
	39	.interval = 1,
	40	.separator = "\|",
4d66492f SK	41	.files = NULL,
	42	.file_count = 0,
	43	.total_width = 0,
9b5ebc12 SK	44	};
9b5ebc12 SK	45
77c76070 SK	46	void
	47	file_print_one(File *f)
	48	{
	49	debug(
	50	"File "
	51	"{"
	52	" name = %s,"
	53	" fd = %d,"
	54	" width = %d,"
	55	" last_read = %d,"
	56	" ttl = %d,"
	57	" pos = %d,"
	58	" next = %p,"
	59	" }\n",
	60	f->name,
	61	f->fd,
	62	f->width,
	63	f->last_read,
	64	f->ttl,
	65	f->pos,
	66	f->next
	67	);
	68	}
	69
	70	void
	71	file_print_all(File *head)
	72	{
	73	for (File *f = head; f; f = f->next) {
	74	file_print_one(f);
	75	}
	76	}
	77
	78	void
	79	config_print(Config *c)
	80	{
	81	debug(
	82	"Config "
	83	"{"
	84	" interval = %d,"
	85	" separator = %s,"
	86	" file_count = %d,"
	87	" total_width = %d,"
	88	" files = ..."
	89	" }\n",
	90	c->interval,
	91	c->separator,
	92	c->file_count,
	93	c->total_width
	94	);
	95	file_print_all(c->files);
	96	}
9b5ebc12 SK	97
	98	int
	99	is_pos_num(char *s)
	100	{
	101	while (*s != '\0')
	102	if (!isdigit(*(s++)))
	103	return 0;
	104	return 1;
	105	}
	106
	107	void
	108	print_usage()
	109	{
4d66492f	110	assert(argv0);
9b5ebc12 SK	111	fprintf(
	112	stderr,
	113	"\n"
4d66492f	114	"Usage: %s [OPTION ...] SPEC [SPEC ...]\n"
9b5ebc12	115	"\n"
4d66492f SK	116	" SPEC = FILE_PATH DATA_WIDTH DATA_TTL\n"
	117	" FILE_PATH = string\n"
	118	" DATA_WIDTH = int (* (positive) number of characters *)\n"
	119	" DATA_TTL = int (* (positive) number of seconds *)\n"
	120	" OPTION = -i INTERVAL\n"
	121	" \| -s SEPARATOR\n"
	122	" SEPARATOR = string\n"
	123	" INTERVAL = int (* (positive) number of seconds *)\n"
9b5ebc12	124	"\n",
4d66492f	125	argv0
9b5ebc12 SK	126	);
	127	fprintf(
	128	stderr,
	129	"Example: %s -i 1 /dev/shm/khatus/khatus_sensor_x 4 10\n"
	130	"\n",
4d66492f	131	argv0
9b5ebc12 SK	132	);
	133	}
	134
4d66492f	135	void opts_parse_any(Config , int, char [], int); /* For mutually-recursive calls. */
9b5ebc12 SK	136
9b5ebc12 SK	137	void
4d66492f	138	parse_opts_opt_i(Config cfg, int argc, char argv[], int i)
9b5ebc12 SK	139	{
	140	if (i < argc) {
	141	char *param = argv[i++];
	142
	143	if (is_pos_num(param)) {
4d66492f SK	144	cfg->interval = atoi(param);
4d66492f SK	145	opts_parse_any(cfg, argc, argv, i);
9b5ebc12 SK	146	} else {
	147	usage("Option -i parameter is invalid: \"%s\"\n", param);
	148	}
	149	} else {
	150	usage("Option -i parameter is missing.\n");
	151	}
	152	}
	153
	154	void
4d66492f SK	155	parse_opts_opt_s(Config cfg, int argc, char argv[], int i)
	156	{
	157	if (i < argc) {
3c836bfd	158	cfg->separator = calloc((strlen(argv[i]) + 1), sizeof(char));
4d66492f SK	159	strcpy(cfg->separator, argv[i]);
	160	opts_parse_any(cfg, argc, argv, ++i);
	161	} else {
	162	usage("Option -s parameter is missing.\n");
	163	}
	164	}
	165
4d66492f SK	166	void
4d66492f SK	167	parse_opts_opt(Config cfg, int argc, char argv[], int i)
9b5ebc12 SK	168	{
9b5ebc12 SK	169	switch (argv[i][1]) {
4d66492f SK	170	case 'i': parse_opts_opt_i(cfg, argc, argv, ++i); break; /* TODO: Generic set_int */
4d66492f SK	171	case 's': parse_opts_opt_s(cfg, argc, argv, ++i); break; /* TODO: Generic set_str */
9b5ebc12 SK	172	default : usage("Option \"%s\" is invalid\n", argv[i]);
	173	}
	174	}
	175
	176	void
4d66492f	177	parse_opts_spec(Config cfg, int argc, char argv[], int i)
9b5ebc12 SK	178	{
	179	if ((i + 3) > argc)
	180	usage("[spec] Parameter(s) missing for file \"%s\".\n", argv[i]);
	181
	182	char *n = argv[i++];
	183	char *w = argv[i++];
	184	char *t = argv[i++];
	185
	186	if (!is_pos_num(w))
	187	usage("[spec] Invalid width: \"%s\", for file \"%s\"\n", w, n);
	188	if (!is_pos_num(t))
	189	usage("[spec] Invalid TTL: \"%s\", for file \"%s\"\n", t, n);
3c836bfd	190	File *f = calloc(1, sizeof(struct File));
9b5ebc12	191	if (f) {
4d66492f SK	192	f->name = n;
	193	f->fd = -1;
	194	f->width = atoi(w);
	195	f->ttl = atoi(t);
	196	f->last_read = 0;
	197	f->pos = cfg->total_width;
	198	f->next = cfg->files;
	199
	200	cfg->files = f;
	201	cfg->total_width += f->width;
	202	cfg->file_count++;
9b5ebc12	203	} else {
4d66492f	204	fatal("[memory] Allocation failure.");
9b5ebc12	205	}
4d66492f	206	opts_parse_any(cfg, argc, argv, i);
9b5ebc12 SK	207	}
	208
	209	void
4d66492f	210	opts_parse_any(Config cfg, int argc, char argv[], int i)
9b5ebc12 SK	211	{
	212	if (i < argc) {
	213	switch (argv[i][0]) {
4d66492f SK	214	case '-': parse_opts_opt(cfg, argc, argv, i); break;
	215	default : parse_opts_spec(cfg, argc, argv, i);
	216	}
	217	}
	218	}
	219
	220	void
	221	opts_parse(Config cfg, int argc, char argv[], int i)
	222	{
	223	opts_parse_any(cfg, argc, argv, 1);
	224
	225	File *last = cfg->files;
	226	cfg->files = NULL;
	227	for (File *f = last; f; ) {
	228	File *next = f->next;
	229	f->next = cfg->files;
	230	cfg->files = f;
	231	f = next;
	232	}
	233	}
	234
77c76070 SK	235	void
	236	read_one(File f, char buf)
	237	{
	238	ssize_t n;
	239	char *b;
	240
	241	b = buf + f->pos;
	242	memset(b, ' ', f->width);
	243	while ((n = read(f->fd, b, f->width)) > 0) {
	244	b += n;
	245	debug("read %zd from %s\n", n, f->name);
	246	}
	247
	248	if (n > -1) {
	249	if (*(b - 1) == '\n')
	250	*(b - 1) = ' ';
	251	} else {
	252	error(
	253	"Failed to read: \"%s\". Error: %s\n",
	254	f->name,
	255	strerror(errno)
	256	);
	257	}
	258
	259	close(f->fd);
	260	f->fd = -1;
	261	}
	262
4d66492f SK	263	void
	264	read_all(Config cfg, char buf)
	265	{
77c76070 SK	266	fd_set fds;
	267	int maxfd;
	268	int ready;
	269
	270	FD_ZERO(&fds);
	271
4d66492f SK	272	/* TODO: stat then check TTL */
4d66492f SK	273	for (File *f = cfg->files; f; f = f->next) {
77c76070	274	debug("opening: %s\n", f->name);
4d66492f	275	if (f->fd < 0)
77c76070 SK	276	f->fd = open(f->name, O_RDONLY \| O_NONBLOCK);
77c76070 SK	277	if (f->fd == -1)
4d66492f SK	278	/* TODO: Consider backing off retries for failed files. */
4d66492f SK	279	fatal("Failed to open \"%s\"\n", f->name);
77c76070 SK	280	if (f->fd > maxfd)
	281	maxfd = f->fd;
	282	FD_SET(f->fd, &fds);
	283	}
	284	debug("selecting...\n");
	285	ready = select(maxfd + 1, &fds, NULL, NULL, NULL);
	286	debug("ready: %d\n", ready);
	287	assert(ready != 0);
	288	if (ready < 0)
	289	fatal("%s", strerror(errno));
	290	for (File *f = cfg->files; f; f = f->next) {
	291	if (FD_ISSET(f->fd, &fds)) {
	292	debug("reading: %s\n", f->name);
	293	read_one(f, buf);
9b5ebc12 SK	294	}
	295	}
	296	}
	297
	298	int
4d66492f	299	main(int argc, char *argv[])
9b5ebc12	300	{
4d66492f SK	301	int width;
	302	int nfiles = 0;
	303	int seplen;
	304	int prefix = 0;
	305	char *buf;
	306	Config *cfg = &defaults;
	307
	308	argv0 = argv[0];
	309
	310	opts_parse(cfg, argc, argv, 1);
	311	debug("argv0 = %s\n", argv0);
77c76070	312	config_print(cfg);
4d66492f	313	if (cfg->files == NULL)
9b5ebc12	314	usage("No file specs were given!\n");
4d66492f SK	315
	316	width = cfg->total_width;
	317	seplen = strlen(cfg->separator);
	318
	319	/* 1st pass to make space for separators */
	320	for (File *f = cfg->files; f; f = f->next) {
	321	f->pos += prefix;
	322	prefix += seplen;
	323	nfiles++;
	324	}
	325	width += (seplen * (nfiles - 1));
3c836bfd	326	buf = calloc(1, width + 1);
4d66492f SK	327	if (buf == NULL)
	328	fatal("[memory] Failed to allocate buffer of %d bytes", width);
	329	memset(buf, ' ', width);
	330	buf[width] = '\0';
	331	/* 2nd pass to set the separators */
	332	for (File *f = cfg->files; f; f = f->next) {
	333	if (f->pos) { /* Skip the first, left-most */
77c76070 SK	334	/* Copying only seplen ensures we omit the '\0' byte. */
77c76070 SK	335	strncpy(buf + (f->pos - seplen), cfg->separator, seplen);
4d66492f SK	336	}
	337	}
	338
77c76070	339	printf("%s\n", buf);
4d66492f SK	340	/* TODO: nanosleep and nano time diff */
	341	for (;;) {
	342	read_all(cfg, buf);
	343	printf("%s\n", buf);
4d66492f	344	}
9b5ebc12	345	}