From 9dd094daeb31368a84fcdca35550392b2442d249 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonygarnockjones@gmail.com>
Date: Sun, 2 Jan 2011 15:06:17 -0500
Subject: [PATCH] Save (and print) errno on socket error

---
 harness.c | 4 ++++
 harness.h | 1 +
 relay.c   | 3 ++-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/harness.c b/harness.c
index e7d1b80..9c891b3 100644
--- a/harness.c
+++ b/harness.c
@@ -4,6 +4,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <stddef.h>
+#include <errno.h>
 
 #include <sys/time.h>
 
@@ -166,12 +167,14 @@ static void output_isr(struct bufferevent *bufev, IOHandle *h) {
 
 static void error_isr(struct bufferevent *bufev, short what, IOHandle *h) {
   unsigned short kind = what & ~(EVBUFFER_READ | EVBUFFER_WRITE);
+  int saved_errno = errno;
   info("error_isr 0x%04X fd %d\n", what, h->fd);
   h->error_direction = what & (EVBUFFER_READ | EVBUFFER_WRITE);
   if (kind == EVBUFFER_EOF) {
     h->eof = 1;
   } else {
     h->error_kind = kind;
+    h->error_errno = saved_errno;
   }
   awaken_waiters(h, EV_READ | EV_WRITE);
 }
@@ -205,6 +208,7 @@ void delete_iohandle(IOHandle *h) {
 void iohandle_clear_error(IOHandle *h) {
   h->error_direction = 0;
   h->error_kind = 0;
+  h->error_errno = 0;
 }
 
 static void block_on_io(IOHandle *h, short event) {
diff --git a/harness.h b/harness.h
index 1bff1f6..552044c 100644
--- a/harness.h
+++ b/harness.h
@@ -24,6 +24,7 @@ typedef struct IOHandle {
   int eof;
   unsigned short error_direction;
   unsigned short error_kind;
+  int error_errno;
 } IOHandle;
 
 extern IOHandle *stdin_h;
diff --git a/relay.c b/relay.c
index 888e643..c9268e5 100644
--- a/relay.c
+++ b/relay.c
@@ -182,7 +182,8 @@ static void relay_main(node_t *n) {
 	break;
 
       default:
-	warn("Relay handle error on fd %d: 0x%04X\n", r->fd, inh->error_kind);
+	warn("Relay handle error 0x%04X on fd %d: %d, %s\n",
+	     inh->error_kind, r->fd, inh->error_errno, strerror(inh->error_errno));
 	break;
     }
   }