From 6811223ddffb40fad91977f18ef120628080bc0b Mon Sep 17 00:00:00 2001
From: chris mikkelson <chris@mikk.net>
Date: Wed, 1 Apr 2009 23:47:31 -0500
Subject: [PATCH] Set connection fds to nonblocking, detect blocked writes
 (reads *should* not block, since they only occur when the I/O thread gets a
 readability event).

---
 io.c   | 4 ++++
 smtp.c | 8 ++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/io.c b/io.c
index 2d56936..537a14b 100644
--- a/io.c
+++ b/io.c
@@ -1,5 +1,6 @@
 #include <stdlib.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include <assert.h>
 #include <string.h>
 
@@ -96,6 +97,9 @@ write_cb(int fd, short event, void *data)
 void
 io_initconn(struct conn *c)
 {
+	int flags = fcntl(c->fd, F_GETFL);
+	flags |= O_NONBLOCK;
+	fcntl(c->fd, F_SETFL, flags);
 	event_set(&c->re, c->fd, EV_READ, read_cb, (void *)c);
 	event_base_set(io_base, &c->re);
 	event_set(&c->we, c->fd, EV_WRITE, write_cb, (void *)c);
diff --git a/smtp.c b/smtp.c
index 7b16300..187f728 100644
--- a/smtp.c
+++ b/smtp.c
@@ -3,6 +3,7 @@
 #include <stdarg.h>
 #include <string.h>
 #include <unistd.h>
+#include <sys/errno.h>
 #include <assert.h>
 #include <ctype.h>
 
@@ -39,8 +40,11 @@ respond(struct conn *c, const char *fmt, ...)
 	if (ret < 0) assert(0);	
 	nw = write(c->fd, buf, ret);
 	if (nw < 0) {
-		c->state = SMTP_CLOSED;
-		return 0;
+		if (errno != EAGAIN) {
+			c->state = SMTP_CLOSED;
+			return 0;
+		}
+		nw = 0;
 	}
 	if (nw < ret) {
 		if (!(c->wdata.s = malloc(ret - nw))) {
-- 
2.50.1