#include "khatus_lib_log.h"
#include "khatus_lib_time.h"
-#define usage(...) {print_usage(); fprintf(stderr, "Error:\n " __VA_ARGS__); exit(EXIT_FAILURE);}
+#define usage(...) { \
+ print_usage(); \
+ fprintf(stderr, "Error:\n " __VA_ARGS__); \
+ exit(EXIT_FAILURE); \
+}
#define ERRMSG "ERROR"
static const char errmsg[] = ERRMSG;
char *name;
int fd;
int width;
- int last_read;
- int ttl;
- int pos; /* Position on the output buffer. */
+ 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;
};
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,
+};
+
+enum read_status {
+ END_OF_FILE,
+ END_OF_MESSAGE,
+ RETRY,
+ FAILURE
};
void
" name = %s,"
" fd = %d,"
" width = %d,"
- " last_read = %d,"
- " ttl = %d,"
- " pos = %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,
- f->ttl,
- f->pos,
+ 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
);
}
" 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"
+ " 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 = int (* (positive) number of seconds *)\n"
+ " INTERVAL = float (* (positive) number of seconds *)\n"
" LOG_LEVEL = int (* %d through %d *)\n"
"\n",
argv0,
);
}
-void opts_parse_any(Config *, int, char *[], int); /* For mutually-recursive calls. */
+/* For mutually-recursive calls. */
+void opts_parse_any(Config *, int, char *[], int);
void
parse_opts_opt_i(Config *cfg, int argc, char *argv[], int i)
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);
+ 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);
}
parse_opts_spec(Config *cfg, int argc, char *argv[], int i)
{
if ((i + 3) > argc)
- usage("[spec] Parameter(s) missing for fifo \"%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 fifo \"%s\"\n", w, n);
- if (!is_pos_num(t))
+ 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->fd = -1;
f->width = atoi(w);
- f->ttl = atoi(t);
- f->last_read = 0;
- f->pos = cfg->total_width;
+ 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;
}
}
+void
+fifo_expire(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_read_error(Fifo *f, char *buf)
{
char *b;
int i;
- b = buf + f->pos;
+ b = buf + f->pos_init;
/* Copy as much of the error message as possible.
- * EXCLUDING the reminating \0. */
+ * EXCLUDING the terminating \0. */
for (i = 0; i < errlen && i < f->width; i++)
b[i] = errmsg[i];
/* Any remaining slots: */
b[i] = '_';
}
-void
-fifo_read_one(Fifo *f, char *buf)
+enum read_status
+fifo_read_one(Fifo *f, struct timespec t, char *buf)
{
- ssize_t current;
- ssize_t total;
- char *b;
- char c;
+ char c; /* Character read. */
+ int r; /* Remaining unused slots in buffer range. */
- current = 0;
- total = 0;
- c = '\0';
- b = buf + f->pos;
- while ((current = read(f->fd, &c, 1)) && c != '\n' && c != '\0' && total++ < f->width)
- *b++ = c;
- if (current == -1) {
- error("Failed to read: \"%s\". Error: %s\n", f->name, strerror(errno));
- fifo_read_error(f, buf);
- } else {
- while (total++ < f->width)
- *b++ = ' ';
+ 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. */
+ /*
+ * TODO Define max after which we stop reading.
+ * To ensure that a rogue large message
+ * doesn't trap us here.
+ */
+ }
+ break;
+ default:
+ assert(0);
+ }
}
- /* TODO Record timestamp read */
- close(f->fd);
- f->fd = -1;
}
void
-fifo_read_all(Config *cfg, char *buf)
+fifo_read_all(Config *cfg, struct timespec *ti, char *buf)
{
fd_set fds;
int maxfd = -1;
- int ready;
+ int ready = 0;
struct stat st;
+ struct timespec t;
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));
+ error(
+ "Cannot stat \"%s\". Error: %s\n",
+ f->name,
+ strerror(errno)
+ );
fifo_read_error(f, buf);
continue;
}
fifo_read_error(f, buf);
continue;
}
- debug("opening: %s\n", f->name);
- if (f->fd < 0)
+ 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. */
+ /* 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);
+ ready = pselect(maxfd + 1, &fds, NULL, NULL, ti, NULL);
debug("ready: %d\n", ready);
- assert(ready != 0);
- if (ready < 0)
- fatal("%s", strerror(errno));
- for (Fifo *f = cfg->fifos; f; f = f->next) {
- if (FD_ISSET(f->fd, &fds)) {
- debug("reading: %s\n", f->name);
- fifo_read_one(f, buf);
+ clock_gettime(CLOCK_MONOTONIC, &t);
+ if (ready == -1) {
+ switch (errno) {
+ case EINTR:
+ error("pselect temp failure: %d, errno: %d, msg: %s\n",
+ ready, errno, strerror(errno));
+ /* TODO: Reconsider what to do here. */
+ return;
+ default:
+ fatal("pselect failed: %d, errno: %d, msg: %s\n",
+ ready, errno, strerror(errno));
}
}
+ /* At-least-once ensures that expiries are still checked on timeouts. */
+ do {
+ 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);
+ }
+ } else {
+ fifo_expire(f, t, buf);
+ }
+ }
+ } while (ready);
+ assert(ready == 0);
}
int
main(int argc, char *argv[])
{
+ Config cfg = {
+ .interval = 1.0,
+ .separator = "|",
+ .fifos = NULL,
+ .fifo_count = 0,
+ .total_width = 0,
+ .output_to_x_root_window = 0,
+ };
+
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;
+ Display *d = NULL;
struct stat st;
struct timespec
t0, /* time stamp. before reading fifos */
argv0 = argv[0];
- opts_parse(cfg, argc, argv);
+ opts_parse(&cfg, argc, argv);
debug("argv0 = %s\n", argv0);
- config_print(cfg);
+ config_print(&cfg);
- ti = timespec_of_float(cfg->interval);
+ ti = timespec_of_float(cfg.interval);
- if (cfg->fifos == NULL)
+ 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) {
+ 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));
+ error(
+ "Cannot stat \"%s\". Error: %s\n",
+ f->name,
+ strerror(errno)
+ );
errors++;
continue;
}
}
}
if (errors)
- fatal("Encountered errors with the given file paths. See log.\n");
+ fatal("Encountered errors with given file paths. See log.\n");
- width = cfg->total_width;
- seplen = strlen(cfg->separator);
+ 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 += prefix;
+ 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++;
}
memset(buf, ' ', width);
buf[width] = '\0';
/* 3rd pass to set the separators */
- for (Fifo *f = cfg->fifos; f; f = f->next) {
- if (f->pos) { /* Skip the first, left-most */
+ 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 - seplen), cfg->separator, seplen);
+ 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);
+ if (cfg.output_to_x_root_window && !(d = XOpenDisplay(NULL)))
+ fatal("XOpenDisplay failed with: %p\n", d);
/* TODO: Handle signals */
for (;;) {
clock_gettime(CLOCK_MONOTONIC, &t0); // FIXME: check errors
- /* TODO: Cache expiration. i.e. use the TTL */
- /* TODO: How to trigger TTL check? On select? Alarm signal? */
- /* 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, buf);
- if (cfg->output_to_x_root_window) {
- if (XStoreName(display, DefaultRootWindow(display), buf) < 0)
+ fifo_read_all(&cfg, &ti, buf);
+ if (cfg.output_to_x_root_window) {
+ if (XStoreName(d, DefaultRootWindow(d), buf) < 0)
fatal("XStoreName failed.\n");
- XFlush(display);
+ XFlush(d);
} else {
puts(buf);
fflush(stdout);
}
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);
+ 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.
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