X-Git-Url: https://git.xandkar.net/?p=khatus.git;a=blobdiff_plain;f=x5%2Fkhatus.c;h=43a828bcc719cbf46ca9a67adf15658885461f11;hp=8bbaf8bc16d19fbf922f7982935cdc0a963079f1;hb=17e4ecd509e1ad64c1b083924271603204046b01;hpb=9b5ebc1231a634962f6adbc0919c222101d38053

diff --git a/x5/khatus.c b/x5/khatus.c
index 8bbaf8b..43a828b 100644
--- a/x5/khatus.c
+++ b/x5/khatus.c
@@ -1,41 +1,124 @@
+#include <sys/select.h>
+#include <sys/stat.h>
+
 #include <assert.h>
 #include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <X11/Xlib.h>
 
-#define  MAX_TOT_WIDTH  1024
+#include "bsdtimespec.h"
+#include "khatus_lib_log.h"
+#include "khatus_lib_time.h"
 
-#define debug(   args...) {fprintf(stderr, "[debug] " args);}
-#define error(   args...) {fprintf(stderr, "[error] " args); errors++;}
-#define fatal(n, args...) {fprintf(stderr, "[fatal] " args); exit(n);}
-#define usage(   args...) {print_usage(); fatal(1, "[usage] " args);}
+#define usage(...) {print_usage(); fprintf(stderr, "Error:\n    " __VA_ARGS__); exit(EXIT_FAILURE);}
+#define ERRMSG "ERROR"
 
+static const char errmsg[] = ERRMSG;
+static const int  errlen   = sizeof(ERRMSG) - 1;
 
-typedef struct file * File;
+char *argv0;
 
-struct file {
-	char *  name;
+/* TODO: Convert fifo list to fifo array. */
+typedef struct Fifo Fifo;
+struct Fifo {
+	char   *name;
+	int     fd;
 	int     width;
-	int     ttl;
-	File    next;
+	struct timespec last_read;
+	struct timespec ttl;
+	int     pos_init;  /* Initial position on the output buffer. */
+	int     pos_curr;  /* Current position on the output buffer. */
+	int     pos_final; /* Final   position on the output buffer. */
+	Fifo   *next;
 };
 
-struct options {
-	char * argv0;
-	int    interval;
-	File   files;
-} options = {
-	.argv0    = NULL,
-	.interval = 1,
-	.files    = NULL
+typedef struct Config Config;
+struct Config {
+	double interval;
+	char * separator;
+	Fifo * fifos;
+	int    fifo_count;
+	int    total_width;
+	int    output_to_x_root_window;
+} defaults = {
+	.interval    = 1.0,
+	.separator   = "|",
+	.fifos       = NULL,
+	.fifo_count  = 0,
+	.total_width = 0,
+	.output_to_x_root_window = 0,
 };
 
-typedef struct options * Options;
+enum read_status {
+	END_OF_FILE,
+	END_OF_MESSAGE,
+	RETRY,
+	FAILURE
+};
 
-Options opts   = &options;
-int     errors = 0;
+void
+fifo_print_one(Fifo *f)
+{
+	info("Fifo "
+	    "{"
+	    " name = %s,"
+	    " fd = %d,"
+	    " width = %d,"
+	    " last_read = {tv_sec = %ld, tv_nsec = %ld}"
+	    " ttl = {tv_sec = %ld, tv_nsec = %ld},"
+	    " pos_init = %d,"
+	    " pos_curr = %d,"
+	    " pos_final = %d,"
+	    " next = %p,"
+	    " }\n",
+	    f->name,
+	    f->fd,
+	    f->width,
+	    f->last_read.tv_sec,
+	    f->last_read.tv_nsec,
+	    f->ttl.tv_sec,
+	    f->ttl.tv_nsec,
+	    f->pos_init,
+	    f->pos_curr,
+	    f->pos_final,
+	    f->next
+	);
+}
 
+void
+fifo_print_all(Fifo *head)
+{
+	for (Fifo *f = head; f; f = f->next) {
+		fifo_print_one(f);
+	}
+}
+
+void
+config_print(Config *cfg)
+{
+	info(
+	    "Config "
+	    "{"
+	    " interval = %f,"
+	    " separator = %s,"
+	    " fifo_count = %d,"
+	    " total_width = %d,"
+	    " fifos = ..."
+	    " }\n",
+	    cfg->interval,
+	    cfg->separator,
+	    cfg->fifo_count,
+	    cfg->total_width
+	);
+	fifo_print_all(cfg->fifos);
+}
 
 int
 is_pos_num(char *s)
@@ -46,114 +129,467 @@ is_pos_num(char *s)
 	return 1;
 }
 
+int
+is_decimal(char *s)
+{
+	char c;
+	int seen = 0;
+
+	while ((c = *(s++)) != '\0')
+		if (!isdigit(c)) {
+			if (c == '.' && !seen++)
+				continue;
+			else
+				return 0;
+		}
+	return 1;
+}
+
 void
 print_usage()
 {
-	assert(opts->argv0);
+	assert(argv0);
 	fprintf(
-		stderr,
-		"\n"
-		"Usage: %s [OPTIONS ...] SPEC [SPEC ...]\n"
-		"\n"
-		"\tSPEC       = FILE_PATH DATA_WIDTH DATA_TTL\n"
-		"\tFILE_PATH  = string\n"
-		"\tDATA_WIDTH = int  (* (positive) number of characters *)\n"
-		"\tDATA_TTL   = int  (* (positive) number of seconds *)\n"
-		"\tOPTION     = -i INTERVAL\n"
-		"\tINTERVAL   = int  (* (positive) number of seconds *)\n"
-		"\n",
-		opts->argv0
+	    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   = float  (* (positive) number of seconds *)\n"
+	    "  OPTION     = -i INTERVAL\n"
+	    "             | -s SEPARATOR\n"
+	    "             | -x (* Output to X root window *)\n"
+	    "             | -l LOG_LEVEL\n"
+	    "  SEPARATOR  = string\n"
+	    "  INTERVAL   = float  (* (positive) number of seconds *)\n"
+	    "  LOG_LEVEL  = int  (* %d through %d *)\n"
+	    "\n",
+	    argv0,
+	    Nothing,
+	    Debug
 	);
 	fprintf(
-		stderr,
-		"Example: %s -i 1 /dev/shm/khatus/khatus_sensor_x 4 10\n"
-		"\n",
-		opts->argv0
+	    stderr,
+	    "Example: %s -i 1 /dev/shm/khatus/khatus_sensor_x 4 10\n"
+	    "\n",
+	    argv0
 	);
 }
 
-void parse_opts(int, char *[], int);  /* For mutually-recursive calls. */
+void opts_parse_any(Config *, int, char *[], int);  /* For mutually-recursive calls. */
 
 void
-parse_opts_opt_i(int argc, char *argv[], int i)
+parse_opts_opt_i(Config *cfg, int argc, char *argv[], int i)
 {
-	if (i < argc) {
-		char *param = argv[i++];
+	char *param;
 
-		if (is_pos_num(param)) {
-			opts->interval = atoi(param);
-			parse_opts(argc, argv, i);
-		} else {
-			usage("Option -i parameter is invalid: \"%s\"\n", param);
-		}
-	} else {
+	if (i >= argc)
 		usage("Option -i parameter is missing.\n");
-	}
+	param = argv[i++];
+	if (!is_decimal(param))
+		usage("Option -i parameter is invalid: \"%s\"\n", param);
+	cfg->interval = atof(param);
+	opts_parse_any(cfg, argc, argv, i);
 }
 
 void
-parse_opts_opt(int argc, char *argv[], int i)
+parse_opts_opt_s(Config *cfg, int argc, char *argv[], int i)
+{
+	if (i >= argc)
+		usage("Option -s parameter is missing.\n");
+	cfg->separator = calloc((strlen(argv[i]) + 1), sizeof(char));
+	strcpy(cfg->separator, argv[i]);
+	opts_parse_any(cfg, argc, argv, ++i);
+}
+
+void
+parse_opts_opt_l(Config *cfg, int argc, char *argv[], int i)
+{
+	char *param;
+	int log_level;
+
+	if (i >= argc)
+		usage("Option -l parameter is missing.\n");
+	param = argv[i++];
+	if (!is_pos_num(param))
+		usage("Option -l parameter is invalid: \"%s\"\n", param);
+	log_level = atoi(param);
+	if (log_level > Debug)
+		usage("Option -l value (%d) exceeds maximum (%d)\n", log_level, Debug);
+	_khatus_lib_log_level = log_level;
+	opts_parse_any(cfg, argc, argv, i);
+}
+
+void
+parse_opts_opt(Config *cfg, int argc, char *argv[], int i)
 {
 	switch (argv[i][1]) {
-		case 'i': parse_opts_opt_i(argc, argv, ++i); break;  /* TODO: Generic set_int */
-		default : usage("Option \"%s\" is invalid\n", argv[i]);
+	case 'i':
+		/* TODO: Generic set_int */
+		parse_opts_opt_i(cfg, argc, argv, ++i);
+		break;
+	case 's':
+		/* TODO: Generic set_str */
+		parse_opts_opt_s(cfg, argc, argv, ++i);
+		break;
+	case 'x':
+		cfg->output_to_x_root_window = 1;
+		opts_parse_any(cfg, argc, argv, ++i);
+		break;
+	case 'l':
+		/* TODO: Generic set_int */
+		parse_opts_opt_l(cfg, argc, argv, ++i);
+		break;
+	default :
+		usage("Option \"%s\" is invalid\n", argv[i]);
 	}
 }
 
 void
-parse_opts_spec(int argc, char *argv[], int i)
+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]);
+		usage("[spec] Parameter(s) missing for fifo \"%s\".\n", argv[i]);
 
 	char *n = argv[i++];
 	char *w = argv[i++];
 	char *t = argv[i++];
 
+	struct timespec last_read;
+
 	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 = malloc(sizeof(struct file));
+		usage("[spec] Invalid width: \"%s\", for fifo \"%s\"\n", w, n);
+	if (!is_decimal(t))
+		usage("[spec] Invalid TTL: \"%s\", for fifo \"%s\"\n", t, n);
+	last_read.tv_sec  = 0;
+	last_read.tv_nsec = 0;
+	Fifo *f = calloc(1, sizeof(struct Fifo));
 	if (f) {
-		f->name     = n;
-		f->width    = atoi(w);
-		f->ttl      = atoi(t);
-		f->next     = opts->files;
-		opts->files = f;
+		f->name      = n;
+		f->fd        = -1;
+		f->width     = atoi(w);
+		f->ttl       = timespec_of_float(atof(t));
+		f->last_read = last_read;
+		f->pos_init  = cfg->total_width;
+		f->pos_curr  = f->pos_init;
+		f->pos_final = f->pos_init + f->width - 1;
+		f->next      = cfg->fifos;
+
+		cfg->fifos        = f;
+		cfg->total_width += f->width;
+		cfg->fifo_count++;
 	} else {
-		fatal(2, "[memory] Allocation failure.");
+		fatal("[memory] Allocation failure.");
 	}
-	parse_opts(argc, argv, i);
+	opts_parse_any(cfg, argc, argv, i);
 }
 
 void
-parse_opts(int argc, char *argv[], int i)
+opts_parse_any(Config *cfg, int argc, char *argv[], int i)
 {
 	if (i < argc) {
 		switch (argv[i][0]) {
-			case '-': parse_opts_opt(argc, argv, i); break;
-			default : parse_opts_spec(argc, argv, i);
+		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[])
+{
+	opts_parse_any(cfg, argc, argv, 1);
+
+	Fifo *last = cfg->fifos;
+	cfg->fifos = NULL;
+	for (Fifo *f = last; f; ) {
+		Fifo *next = f->next;
+		f->next = cfg->fifos;
+		cfg->fifos = f;
+		f = next;
+	}
+}
+
+void
+fifo_expire_one(Fifo *f, struct timespec t, char *buf)
+{
+	struct timespec td;
+
+	timespecsub(&t, &(f->last_read), &td);
+	if (timespeccmp(&td, &(f->ttl), >=)) {
+		/* TODO: Maybe configurable expiry character. */
+		memset(buf + f->pos_init, '_', f->pos_final - f->pos_init);
+		warn("Data source expired: \"%s\"\n", f->name);
+	}
+}
+
+void
+fifo_expire_all(Config *cfg, struct timespec t, char *buf)
+{
+	Fifo *f;
+
+	for (f = cfg->fifos; f; f = f->next)
+		fifo_expire_one(f, t, buf);
+}
+
+void
+fifo_read_error(Fifo *f, char *buf)
+{
+	char *b;
+	int i;
+
+	b = buf + f->pos_init;
+	/* Copy as much of the error message as possible.
+	 * EXCLUDING the terminating \0. */
+	for (i = 0; i < errlen && i < f->width; i++)
+		b[i] = errmsg[i];
+	/* Any remaining slots: */
+	for (; i < f->width; i++)
+		b[i] = '_';
+}
+
+enum read_status
+fifo_read_one(Fifo *f, struct timespec t, char *buf)
+{
+	char c;  /* Character read. */
+	int  r;  /* Remaining unused slots in buffer range. */
+
+	for (;;) {
+		switch (read(f->fd, &c, 1)) {
+		case -1:
+			error("Failed to read: \"%s\". errno: %d, msg: %s\n",
+			    f->name, errno, strerror(errno));
+			switch (errno) {
+			case EINTR:
+			case EAGAIN:
+				return RETRY;
+			default:
+				return FAILURE;
+			}
+		case  0:
+			debug("%s: End of FILE\n", f->name);
+			f->pos_curr = f->pos_init;
+			return END_OF_FILE;
+		case  1:
+			/* TODO: Consider making msg term char a CLI option */
+			if (c == '\n' || c == '\0') {
+				r = f->pos_final - f->pos_curr;
+				if (r > 0)
+					memset(buf + f->pos_curr, ' ', r);
+				f->pos_curr = f->pos_init;
+				f->last_read = t;
+				return END_OF_MESSAGE;
+			} else {
+				if (f->pos_curr <= f->pos_final)
+					buf[f->pos_curr++] = c;
+				/* Drop beyond available range. */
+			}
+			break;
+		default:
+			assert(0);
 		}
 	}
 }
 
+void
+fifo_read_all(Config *cfg, struct timespec t, char *buf)
+{
+	fd_set fds;
+	int maxfd = -1;
+	int ready = 0;
+	struct stat st;
+
+	FD_ZERO(&fds);
+	for (Fifo *f = cfg->fifos; f; f = f->next) {
+		/* TODO: Create the FIFO if it doesn't already exist. */
+		if (lstat(f->name, &st) < 0) {
+			error("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
+			fifo_read_error(f, buf);
+			continue;
+		}
+		if (!(st.st_mode & S_IFIFO)) {
+			error("\"%s\" is not a FIFO\n", f->name);
+			fifo_read_error(f, buf);
+			continue;
+		}
+		if (f->fd < 0) {
+			debug("%s: closed. opening. fd: %d\n", f->name, f->fd);
+			f->fd = open(f->name, O_RDONLY | O_NONBLOCK);
+		} else {
+			debug("%s: already openned. fd: %d\n", f->name, f->fd);
+		}
+		if (f->fd == -1) {
+			/* TODO: Consider backing off retries for failed fifos. */
+			error("Failed to open \"%s\"\n", f->name);
+			fifo_read_error(f, buf);
+			continue;
+		}
+		debug("%s: open. fd: %d\n", f->name, f->fd);
+		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)
+		/* TODO: Do we really want to fail here? */
+		fatal("%s", strerror(errno));
+	while (ready) {
+		for (Fifo *f = cfg->fifos; f; f = f->next) {
+			if (FD_ISSET(f->fd, &fds)) {
+				debug("reading: %s\n", f->name);
+				switch (fifo_read_one(f, t, buf)) {
+				/*
+				 * ### MESSAGE LOSS ###
+				 * is introduced by closing at EOM in addition
+				 * to EOF, since there may be unread messages
+				 * remaining in the pipe. However,
+				 *
+				 * ### INTER-MESSAGE PUSHBACK ###
+				 * is also gained, since pipes block at the
+				 * "open" call.
+				 *
+				 * This is an acceptable trade-off because we
+				 * are a stateless reporter of a _most-recent_
+				 * status, not a stateful accumulator.
+				 */
+				case END_OF_MESSAGE:
+				case END_OF_FILE:
+				case FAILURE:
+					close(f->fd);
+					f->fd = -1;
+					ready--;
+					break;
+				case RETRY:
+					break;
+				default:
+					assert(0);
+				}
+			}
+		}
+	}
+	assert(ready == 0);
+}
+
 int
-main(int argc, char **argv)
-{
-	opts->argv0 = argv[0];
-	parse_opts(argc, argv, 1);
-	assert(!errors);
-	debug("[options] argv0 = %s\n", opts->argv0);
-	debug("[options] interval = %d\n", opts->interval);
-	if (opts->files == NULL)
-		usage("No file specs were given!\n");
-	for (File f = opts->files; f; f = f->next) {
-		debug(
-			"[options] file = { name = %s, width = %d, ttl = %d }\n",
-			f->name,
-			f->width,
-			f->ttl
-		);
+main(int argc, char *argv[])
+{
+	int width  = 0;
+	int nfifos = 0;
+	int seplen = 0;
+	int prefix = 0;
+	int errors = 0;
+	char *buf;
+	Config cfg0 = defaults;
+	Config *cfg = &cfg0;
+	Display *display = NULL;
+	struct stat st;
+	struct timespec
+		t0,  /* time stamp. before reading fifos */
+		t1,  /* time stamp. after  reading fifos */
+		ti,  /* time interval desired    (t1 - t0) */
+		td,  /* time interval measured   (t1 - t0) */
+		tc;  /* time interval correction (ti - td) when td < ti */
+
+	argv0 = argv[0];
+
+	opts_parse(cfg, argc, argv);
+	debug("argv0 = %s\n", argv0);
+	config_print(cfg);
+
+	ti = timespec_of_float(cfg->interval);
+
+	if (cfg->fifos == NULL)
+		usage("No fifo specs were given!\n");
+
+	/* 1st pass to check file existence and type */
+	for (Fifo *f = cfg->fifos; f; f = f->next) {
+		if (lstat(f->name, &st) < 0) {
+			error("Cannot stat \"%s\". Error: %s\n", f->name, strerror(errno));
+			errors++;
+			continue;
+		}
+		if (!(st.st_mode & S_IFIFO)) {
+			error("\"%s\" is not a FIFO\n", f->name);
+			errors++;
+			continue;
+		}
 	}
+	if (errors)
+		fatal("Encountered errors with the given file paths. See log.\n");
+
+	width  = cfg->total_width;
+	seplen = strlen(cfg->separator);
+
+	/* 2nd pass to make space for separators */
+	for (Fifo *f = cfg->fifos; f; f = f->next) {
+		f->pos_init  += prefix;
+		f->pos_final += prefix;
+		f->pos_curr = f->pos_init;
+		prefix += seplen;
+		nfifos++;
+	}
+	width += (seplen * (nfifos - 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';
+	/* 3rd pass to set the separators */
+	for (Fifo *f = cfg->fifos; f; f = f->next) {
+		if (f->pos_init) {  /* Skip the first, left-most */
+			/* Copying only seplen ensures we omit the '\0' byte. */
+			strncpy(buf + (f->pos_init - seplen), cfg->separator, seplen);
+		}
+	}
+
+	if (cfg->output_to_x_root_window && !(display = XOpenDisplay(NULL)))
+		fatal("XOpenDisplay failed with: %p\n", display);
+	/* TODO: Handle signals */
+	for (;;) {
+		clock_gettime(CLOCK_MONOTONIC, &t0); // FIXME: check errors
+		/* TODO: Set timeout on fifo_read_all based on diff of last time of
+		 *       fifo_read_all and desired time of next TTL check?
+		 */
+		/* TODO: How long to wait on IO? Max TTL? */
+		fifo_read_all(cfg, t0, buf);
+		if (cfg->output_to_x_root_window) {
+			if (XStoreName(display, DefaultRootWindow(display), buf) < 0)
+				fatal("XStoreName failed.\n");
+			XFlush(display);
+		} else {
+			puts(buf);
+			fflush(stdout);
+		}
+
+		/*
+		 * This is a good place for expiry check, since we're about to
+		 * sleep anyway and the time taken by the check will be
+		 * subtracted from the sleep period.
+		 */
+		fifo_expire_all(cfg, t0, buf);
+
+		clock_gettime(CLOCK_MONOTONIC, &t1); // FIXME: check errors
+		timespecsub(&t1, &t0, &td);
+		debug("td {tv_sec = %ld, tv_nsec = %ld}\n", td.tv_sec, td.tv_nsec);
+		if (timespeccmp(&td, &ti, <)) {
+			/* Pushback on data producers by refusing to read the
+			 * pipe more frequently than the interval.
+			 */
+			timespecsub(&ti, &td, &tc);
+			debug("snooze YES\n");
+			snooze(&tc);
+		} else {
+			debug("snooze NO\n");
+		}
+	}
+
+	return EXIT_SUCCESS;
 }