X-Git-Url: https://git.xandkar.net/?a=blobdiff_plain;f=x5%2Fkhatus.c;h=62b3774fdb21c18604dfd4da7de1e11f8b1fe926;hb=80e23f5474b94b36f66c0406425f2214d89eaf6e;hp=4c8a6656fa8f702c15b5cefe81f1ee7f8120f606;hpb=8ce5d971312e8bb27817e359e9712b3edfe011b5;p=khatus.git

diff --git a/x5/khatus.c b/x5/khatus.c
index 4c8a665..62b3774 100644
--- a/x5/khatus.c
+++ b/x5/khatus.c
@@ -328,15 +328,11 @@ fifo_read_error(Fifo *f, char *buf)
 enum read_status
 fifo_read_one(Fifo *f, char *buf)
 {
-	/* Initialize all to an impossible value: */
-	ssize_t n = -5;  /* Number of bytes read. */
-	char    c = -1;  /* Character read. */
-	int     r = -1;  /* Remaining unused slots in buffer range. */
+	char c;  /* Character read. */
+	int  r;  /* Remaining unused slots in buffer range. */
 
 	for (;;) {
-		n = read(f->fd, &c, 1);
-		assert(n >= -1 && n <= 1);
-		switch (n) {
+		switch (read(f->fd, &c, 1)) {
 		case -1:
 			error("Failed to read: \"%s\". errno: %d, msg: %s\n",
 			    f->name, errno, strerror(errno));
@@ -377,7 +373,7 @@ fifo_read_all(Config *cfg, char *buf)
 {
 	fd_set fds;
 	int maxfd = -1;
-	int ready;
+	int ready = 0;
 	struct stat st;
 
 	FD_ZERO(&fds);
@@ -415,24 +411,43 @@ fifo_read_all(Config *cfg, char *buf)
 	debug("ready: %d\n", ready);
 	assert(ready != 0);
 	if (ready < 0)
+		/* TODO: Do we really want to fail here? */
 		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);
-			switch (fifo_read_one(f, buf)) {
-			case END_OF_FILE:
-			case FAILURE:
-				close(f->fd);
-				f->fd = -1;
-				break;
-			case END_OF_MESSAGE:
-			case RETRY:
-				break;
-			default:
-				assert(0);
+	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, 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