}
#define ERRMSG "ERROR"
+
static const char errmsg[] = ERRMSG;
static const int errlen = sizeof(ERRMSG) - 1;
FAILURE
};
+Slot *
+slots_rev(Slot *old)
+{
+ Slot *tmp = NULL;
+ Slot *new = NULL;
+
+ while (old) {
+ tmp = old->next;
+ old->next = new;
+ new = old;
+ old = tmp;
+ }
+ return new;
+}
+
void
-slot_print_one(Slot *s)
+slot_print(Slot *s)
{
khlib_info("Slot "
"{"
}
void
-slot_print_all(Slot *head)
+slots_print(Slot *head)
{
for (Slot *s = head; s; s = s->next) {
- slot_print_one(s);
+ slot_print(s);
+ }
+}
+
+void
+slot_expire(Slot *s, struct timespec t, char *buf)
+{
+ struct timespec td;
+
+ timespecsub(&t, &(s->in_last_read), &td);
+ if (timespeccmp(&td, &(s->out_ttl), >=)) {
+ /* TODO: Maybe configurable expiry character. */
+ memset(buf + s->out_pos_lo, '_', s->out_width);
+ khlib_warn("Slot expired: \"%s\"\n", s->in_fifo);
+ }
+}
+
+void
+slot_set_error(Slot *s, char *buf)
+{
+ char *b;
+ int i;
+
+ s->in_fd = -1;
+ b = buf + s->out_pos_lo;
+ /* Copy as much of the error message as possible.
+ * EXCLUDING the terminating \0. */
+ for (i = 0; i < errlen && i < s->out_width; i++)
+ b[i] = errmsg[i];
+ /* Any remaining positions: */
+ memset(b + i, '_', s->out_width - i);
+}
+
+enum read_status
+slot_read(Slot *s, struct timespec t, char *buf)
+{
+ char c; /* Character read. */
+ int r; /* Remaining unused positions in buffer range. */
+
+ for (;;) {
+ switch (read(s->in_fd, &c, 1)) {
+ case -1:
+ khlib_error(
+ "Failed to read: \"%s\". errno: %d, msg: %s\n",
+ s->in_fifo,
+ errno,
+ strerror(errno)
+ );
+ switch (errno) {
+ case EINTR:
+ case EAGAIN:
+ return RETRY;
+ default:
+ return FAILURE;
+ }
+ case 0:
+ khlib_debug("%s: End of FILE\n", s->in_fifo);
+ s->out_pos_cur = s->out_pos_lo;
+ return END_OF_FILE;
+ case 1:
+ /* TODO: Consider making msg term char a CLI option */
+ if (c == '\n' || c == '\0') {
+ r = (s->out_pos_hi - s->out_pos_cur) + 1;
+ if (r > 0)
+ memset(buf + s->out_pos_cur, ' ', r);
+ s->out_pos_cur = s->out_pos_lo;
+ s->in_last_read = t;
+ return END_OF_MESSAGE;
+ } else {
+ if (s->out_pos_cur <= s->out_pos_hi)
+ buf[s->out_pos_cur++] = 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);
+ }
}
}
+void
+slots_read(Config *cfg, struct timespec *ti, char *buf)
+{
+ fd_set fds;
+ int maxfd = -1;
+ int ready = 0;
+ struct stat st;
+ struct timespec t;
+ Slot *s;
+
+ FD_ZERO(&fds);
+ for (s = cfg->slots; s; s = s->next) {
+ /* TODO: Create the FIFO if it doesn't already exist. */
+ if (lstat(s->in_fifo, &st) < 0) {
+ khlib_error(
+ "Cannot stat \"%s\". Error: %s\n",
+ s->in_fifo,
+ strerror(errno)
+ );
+ slot_set_error(s, buf);
+ continue;
+ }
+ if (!(st.st_mode & S_IFIFO)) {
+ khlib_error("\"%s\" is not a FIFO\n", s->in_fifo);
+ slot_set_error(s, buf);
+ continue;
+ }
+ if (s->in_fd < 0) {
+ khlib_debug(
+ "%s: closed. opening. in_fd: %d\n",
+ s->in_fifo,
+ s->in_fd
+ );
+ s->in_fd = open(s->in_fifo, O_RDONLY | O_NONBLOCK);
+ } else {
+ khlib_debug(
+ "%s: already openned. in_fd: %d\n",
+ s->in_fifo,
+ s->in_fd
+ );
+ }
+ if (s->in_fd == -1) {
+ /* TODO Consider backing off retries for failed slots */
+ khlib_error("Failed to open \"%s\"\n", s->in_fifo);
+ slot_set_error(s, buf);
+ continue;
+ }
+ khlib_debug("%s: open. in_fd: %d\n", s->in_fifo, s->in_fd);
+ if (s->in_fd > maxfd)
+ maxfd = s->in_fd;
+ FD_SET(s->in_fd, &fds);
+ }
+ khlib_debug("selecting...\n");
+ ready = pselect(maxfd + 1, &fds, NULL, NULL, ti, NULL);
+ khlib_debug("ready: %d\n", ready);
+ clock_gettime(CLOCK_MONOTONIC, &t);
+ if (ready == -1) {
+ switch (errno) {
+ case EINTR:
+ khlib_error(
+ "pselect temp failure: %d, errno: %d, msg: %s\n",
+ ready,
+ errno,
+ strerror(errno)
+ );
+ /* TODO: Reconsider what to do here. */
+ return;
+ default:
+ khlib_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 (s = cfg->slots; s; s = s->next) {
+ if (s->in_fd < 0)
+ continue;
+ if (FD_ISSET(s->in_fd, &fds)) {
+ khlib_debug("reading: %s\n", s->in_fifo);
+ switch (slot_read(s, 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.
+ *
+ * ### LOSSLESS ALTERNATIVES ###
+ * - Read each pipe until EOF before reading
+ * another.
+ * PROBLEM: a fast writer can trap us in the
+ * read loop.
+ *
+ * - Read each pipe until EOM, but close only
+ * at EOF.
+ * PROBLEM: a fast writer can fill the pipe
+ * faster than we can read it and we end-up
+ * displaying stale data.
+ *
+ */
+ case END_OF_MESSAGE:
+ case END_OF_FILE:
+ case FAILURE:
+ close(s->in_fd);
+ s->in_fd = -1;
+ ready--;
+ break;
+ case RETRY:
+ break;
+ default:
+ assert(0);
+ }
+ } else {
+ slot_expire(s, t, buf);
+ }
+ }
+ } while (ready);
+ assert(ready == 0);
+}
+
void
config_print(Config *cfg)
{
cfg->slot_count,
cfg->total_width
);
- slot_print_all(cfg->slots);
+ slots_print(cfg->slots);
}
int
void
parse_opts_spec(Config *cfg, int argc, char *argv[], int i)
{
+ char *n;
+ char *w;
+ char *t;
+ struct timespec in_last_read;
+ Slot *s;
+
if ((i + 3) > argc)
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 in_last_read;
+ n = argv[i++];
+ w = argv[i++];
+ t = argv[i++];
if (!is_pos_num(w))
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);
+
in_last_read.tv_sec = 0;
in_last_read.tv_nsec = 0;
- Slot *s = calloc(1, sizeof(struct Slot));
+ s = calloc(1, sizeof(struct Slot));
+
if (s) {
s->in_fifo = n;
s->in_fd = -1;
- s->out_width = atoi(w);
- s->out_ttl = khlib_timespec_of_float(atof(t));
+ s->out_width = atoi(w);
+ s->out_ttl = khlib_timespec_of_float(atof(t));
s->in_last_read = in_last_read;
- s->out_pos_lo = cfg->total_width;
+ s->out_pos_lo = cfg->total_width;
s->out_pos_cur = s->out_pos_lo;
- s->out_pos_hi = s->out_pos_lo + s->out_width - 1;
- s->next = cfg->slots;
+ s->out_pos_hi = s->out_pos_lo + s->out_width - 1;
+ s->next = cfg->slots;
cfg->slots = s;
cfg->total_width += s->out_width;
opts_parse(Config *cfg, int argc, char *argv[])
{
opts_parse_any(cfg, argc, argv, 1);
-
- Slot *last = cfg->slots;
- cfg->slots = NULL;
- for (Slot *s = last; s; ) {
- Slot *next = s->next;
- s->next = cfg->slots;
- cfg->slots = s;
- s = next;
- }
-}
-
-void
-slot_expire(Slot *s, struct timespec t, char *buf)
-{
- struct timespec td;
-
- timespecsub(&t, &(s->in_last_read), &td);
- if (timespeccmp(&td, &(s->out_ttl), >=)) {
- /* TODO: Maybe configurable expiry character. */
- memset(buf + s->out_pos_lo, '_', s->out_pos_hi - s->out_pos_lo);
- khlib_warn("Slot expired: \"%s\"\n", s->in_fifo);
- }
-}
-
-void
-slot_read_error(Slot *s, char *buf)
-{
- char *b;
- int i;
-
- b = buf + s->out_pos_lo;
- /* Copy as much of the error message as possible.
- * EXCLUDING the terminating \0. */
- for (i = 0; i < errlen && i < s->out_width; i++)
- b[i] = errmsg[i];
- /* Any remaining slots: */
- for (; i < s->out_width; i++)
- b[i] = '_';
-}
-
-enum read_status
-slot_read_one(Slot *s, struct timespec t, char *buf)
-{
- char c; /* Character read. */
- int r; /* Remaining unused slots in buffer range. */
-
- for (;;) {
- switch (read(s->in_fd, &c, 1)) {
- case -1:
- khlib_error(
- "Failed to read: \"%s\". errno: %d, msg: %s\n",
- s->in_fifo,
- errno,
- strerror(errno)
- );
- switch (errno) {
- case EINTR:
- case EAGAIN:
- return RETRY;
- default:
- return FAILURE;
- }
- case 0:
- khlib_debug("%s: End of FILE\n", s->in_fifo);
- s->out_pos_cur = s->out_pos_lo;
- return END_OF_FILE;
- case 1:
- /* TODO: Consider making msg term char a CLI option */
- if (c == '\n' || c == '\0') {
- r = s->out_pos_hi - s->out_pos_cur;
- if (r > 0)
- memset(buf + s->out_pos_cur, ' ', r);
- s->out_pos_cur = s->out_pos_lo;
- s->in_last_read = t;
- return END_OF_MESSAGE;
- } else {
- if (s->out_pos_cur <= s->out_pos_hi)
- buf[s->out_pos_cur++] = 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);
- }
- }
-}
-
-void
-slot_read_all(Config *cfg, struct timespec *ti, char *buf)
-{
- fd_set fds;
- int maxfd = -1;
- int ready = 0;
- struct stat st;
- struct timespec t;
-
- FD_ZERO(&fds);
- for (Slot *s = cfg->slots; s; s = s->next) {
- /* TODO: Create the FIFO if it doesn't already exist. */
- if (lstat(s->in_fifo, &st) < 0) {
- khlib_error(
- "Cannot stat \"%s\". Error: %s\n",
- s->in_fifo,
- strerror(errno)
- );
- slot_read_error(s, buf);
- continue;
- }
- if (!(st.st_mode & S_IFIFO)) {
- khlib_error("\"%s\" is not a FIFO\n", s->in_fifo);
- slot_read_error(s, buf);
- continue;
- }
- if (s->in_fd < 0) {
- khlib_debug(
- "%s: closed. opening. in_fd: %d\n",
- s->in_fifo,
- s->in_fd
- );
- s->in_fd = open(s->in_fifo, O_RDONLY | O_NONBLOCK);
- } else {
- khlib_debug(
- "%s: already openned. in_fd: %d\n",
- s->in_fifo,
- s->in_fd
- );
- }
- if (s->in_fd == -1) {
- /* TODO Consider backing off retries for failed slots */
- khlib_error("Failed to open \"%s\"\n", s->in_fifo);
- slot_read_error(s, buf);
- continue;
- }
- khlib_debug("%s: open. in_fd: %d\n", s->in_fifo, s->in_fd);
- if (s->in_fd > maxfd)
- maxfd = s->in_fd;
- FD_SET(s->in_fd, &fds);
- }
- khlib_debug("selecting...\n");
- ready = pselect(maxfd + 1, &fds, NULL, NULL, ti, NULL);
- khlib_debug("ready: %d\n", ready);
- clock_gettime(CLOCK_MONOTONIC, &t);
- if (ready == -1) {
- switch (errno) {
- case EINTR:
- khlib_error(
- "pselect temp failure: %d, errno: %d, msg: %s\n",
- ready,
- errno,
- strerror(errno)
- );
- /* TODO: Reconsider what to do here. */
- return;
- default:
- khlib_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 (Slot *s = cfg->slots; s; s = s->next) {
- if (FD_ISSET(s->in_fd, &fds)) {
- khlib_debug("reading: %s\n", s->in_fifo);
- switch (slot_read_one(s, 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(s->in_fd);
- s->in_fd = -1;
- ready--;
- break;
- case RETRY:
- break;
- default:
- assert(0);
- }
- } else {
- slot_expire(s, t, buf);
- }
- }
- } while (ready);
- assert(ready == 0);
+ cfg->slots = slots_rev(cfg->slots);
}
int
ti, /* time interval desired (t1 - t0) */
td, /* time interval measured (t1 - t0) */
tc; /* time interval correction (ti - td) when td < ti */
+ Slot *s;
argv0 = argv[0];
usage("No slot specs were given!\n");
/* 1st pass to check file existence and type */
- for (Slot *s = cfg.slots; s; s = s->next) {
+ for (s = cfg.slots; s; s = s->next) {
if (lstat(s->in_fifo, &st) < 0) {
khlib_error(
"Cannot stat \"%s\". Error: %s\n",
seplen = strlen(cfg.separator);
/* 2nd pass to make space for separators */
- for (Slot *s = cfg.slots; s; s = s->next) {
+ for (s = cfg.slots; s; s = s->next) {
s->out_pos_lo += prefix;
s->out_pos_hi += prefix;
s->out_pos_cur = s->out_pos_lo;
memset(buf, ' ', width);
buf[width] = '\0';
/* 3rd pass to set the separators */
- for (Slot *s = cfg.slots; s; s = s->next) {
+ for (s = cfg.slots; s; s = s->next) {
if (s->out_pos_lo) { /* Skip the first, left-most */
/* Copying only seplen ensures we omit the '\0' byte. */
strncpy(
/* TODO: Handle signals */
for (;;) {
clock_gettime(CLOCK_MONOTONIC, &t0); // FIXME: check errors
- slot_read_all(&cfg, &ti, buf);
+ slots_read(&cfg, &ti, buf);
if (cfg.output_to_x_root_window) {
if (XStoreName(d, DefaultRootWindow(d), buf) < 0)
khlib_fatal("XStoreName failed.\n");
td.tv_nsec
);
if (timespeccmp(&td, &ti, <)) {
- /* Pushback on data producers by refusing to read the
+ /*
+ * Pushback on data producers by refusing to read the
* pipe more frequently than the interval.
*/
timespecsub(&ti, &td, &tc);
- khlib_debug("khlib_sleep YES\n");
khlib_sleep(&tc);
- } else {
- khlib_debug("khlib_sleep NO\n");
}
}
-
return EXIT_SUCCESS;
}
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