On win32, errno is not the last socket error. Worse, WSAGetLastError() is not the last socket error sometimes (i.e., EWOULDBLOCK). Also, strerror() does not handle winsock errors. Therefore, event_err() and event_warn() are completely wrong for windows socket errors. Fix that.

svn:r936

ChangeLog

@@ -123,7 +123,8 @@ Changes in current version:
  o Make event_add not change any state if it fails; reported by Ian Bell.
  o Fix a bug where headers arriving in multiple packets were not parsed; fix from Jiang Hong; test by me.
  o Match the query in DNS replies to the query in the request; from Vsevolod Stakhov.
-	
+ o Add new utility functions to correctly observe and log winsock errors.
+
 Changes in 1.4.0:
  o allow \r or \n individually to separate HTTP headers instead of the standard "\r\n"; from Charles Kerr.
  o demote most http warnings to debug messages

evdns.c

@@ -362,21 +362,6 @@ static int strtoint(const char *const str);
 
 #ifdef WIN32
 static int
-last_error(evutil_socket_t sock)
-{
-	int optval, optvallen=sizeof(optval);
-	int err = WSAGetLastError();
-	if (err == WSAEWOULDBLOCK && sock >= 0) {
-		if (getsockopt(sock, SOL_SOCKET, SO_ERROR, (void*)&optval,
-			       &optvallen))
-			return err;
-		if (optval)
-			return optval;
-	}
-	return err;
-
-}
-static int
 error_is_eagain(int err)
 {
 	return err == EAGAIN || err == WSAEWOULDBLOCK;
@@ -396,7 +381,6 @@ inet_aton(const char *c, struct in_addr *addr)
 	return 1;
 }
 #else
-#define last_error(sock) (errno)
 #define error_is_eagain(err) ((err) == EAGAIN)
 #endif
 #define CLOSE_SOCKET(s) EVUTIL_CLOSESOCKET(s)
@@ -1183,9 +1167,9 @@ nameserver_read(struct nameserver *ns) {
 	for (;;) {
           	const int r = recv(ns->socket, packet, sizeof(packet), 0);
 		if (r < 0) {
-			int err = last_error(ns->socket);
+			int err = evutil_socket_geterror(ns->socket);
 			if (error_is_eagain(err)) return;
-			nameserver_failed(ns, strerror(err));
+			nameserver_failed(ns, evutil_socket_error_to_string(err));
 			return;
 		}
 		ns->timedout = 0;
@@ -1207,10 +1191,10 @@ server_port_read(struct evdns_server_port *s) {
 		r = recvfrom(s->socket, packet, sizeof(packet), 0,
 					 (struct sockaddr*) &addr, &addrlen);
 		if (r < 0) {
-			int err = last_error(s->socket);
+			int err = evutil_socket_geterror(s->socket);
 			if (error_is_eagain(err)) return;
 			log(EVDNS_LOG_WARN, "Error %s (%d) while reading request.",
-				strerror(err), err);
+				evutil_socket_error_to_string(err), err);
 			return;
 		}
 		request_parse(packet, r, s, (struct sockaddr*) &addr, addrlen);
@@ -1226,10 +1210,10 @@ server_port_flush(struct evdns_server_port *port)
 		int r = sendto(port->socket, req->response, req->response_len, 0,
 			   (struct sockaddr*) &req->addr, req->addrlen);
 		if (r < 0) {
-			int err = last_error(port->socket);
+			int err = evutil_socket_geterror(port->socket);
 			if (error_is_eagain(err))
 				return;
-			log(EVDNS_LOG_WARN, "Error %s (%d) while writing response to port; dropping", strerror(err), err);
+			log(EVDNS_LOG_WARN, "Error %s (%d) while writing response to port; dropping", evutil_socket_error_to_string(err), err);
 		}
 		if (server_request_free(req)) {
 			/* we released the last reference to req->port. */
@@ -1758,7 +1742,7 @@ evdns_server_request_respond(struct evdns_server_request *_req, int err)
 	r = sendto(port->socket, req->response, req->response_len, 0,
 			   (struct sockaddr*) &req->addr, req->addrlen);
 	if (r<0) {
-		int sock_err = last_error(port->socket);
+		int sock_err = evutil_socket_geterror(port->socket);
 		if (! error_is_eagain(sock_err))
 			return -1;
 
@@ -1936,9 +1920,9 @@ static int
 evdns_request_transmit_to(struct evdns_request *req, struct nameserver *server) {
 	const int r = send(server->socket, req->request, req->request_len, 0);
 	if (r < 0) {
-		int err = last_error(server->socket);
+		int err = evutil_socket_geterror(server->socket);
 		if (error_is_eagain(err)) return 1;
-		nameserver_failed(req->ns, strerror(err));
+		nameserver_failed(req->ns, evutil_socket_error_to_string(err));
 		return 2;
 	} else if (r != (int)req->request_len) {
 		return 1;  /* short write */

event.c

@@ -1487,13 +1487,13 @@ evthread_set_id_callback(struct event_base *base,
 #endif
 	base->th_get_id = id_fn;
 	base->th_owner_id = (*id_fn)();
-	/* 
+	/*
 	 * If another thread wants to add a new event, we need to notify
 	 * the thread that owns the base to wakeup for rescheduling.
 	 */
 	if (evutil_socketpair(LOCAL_SOCKETPAIR_AF, SOCK_STREAM, 0,
 		base->th_notify_fd) == -1)
-		event_err(1, "%s: socketpair", __func__);
+		event_sock_err(1, -1, "%s: socketpair", __func__);
 
 	evutil_make_socket_nonblocking(base->th_notify_fd[0]);
 	evutil_make_socket_nonblocking(base->th_notify_fd[1]);

evutil.c

@@ -218,6 +218,100 @@ evutil_gettimeofday(struct timeval *tv, struct timezone *tz)
 }
 #endif
 
+#ifdef WIN32
+int
+evutil_socket_geterror(evutil_socket_t sock)
+{
+	int optval, optvallen=sizeof(optval);
+	int err = WSAGetLastError();
+	if (err == WSAEWOULDBLOCK && sock >= 0) {
+		if (getsockopt(sock, SOL_SOCKET, SO_ERROR, (void*)&optval,
+					   &optvallen))
+			return err;
+		if (optval)
+			return optval;
+	}
+	return err;
+}
+#endif
+
+#ifdef WIN32
+#define E(code, s) { code, (s " [" #code " ]") }
+static struct { int code; const char *msg; } windows_socket_errors[] = {
+  E(WSAEINTR, "Interrupted function call"),
+  E(WSAEACCES, "Permission denied"),
+  E(WSAEFAULT, "Bad address"),
+  E(WSAEINVAL, "Invalid argument"),
+  E(WSAEMFILE, "Too many open files"),
+  E(WSAEWOULDBLOCK,  "Resource temporarily unavailable"),
+  E(WSAEINPROGRESS, "Operation now in progress"),
+  E(WSAEALREADY, "Operation already in progress"),
+  E(WSAENOTSOCK, "Socket operation on nonsocket"),
+  E(WSAEDESTADDRREQ, "Destination address required"),
+  E(WSAEMSGSIZE, "Message too long"),
+  E(WSAEPROTOTYPE, "Protocol wrong for socket"),
+  E(WSAENOPROTOOPT, "Bad protocol option"),
+  E(WSAEPROTONOSUPPORT, "Protocol not supported"),
+  E(WSAESOCKTNOSUPPORT, "Socket type not supported"),
+  /* What's the difference between NOTSUPP and NOSUPPORT? :) */
+  E(WSAEOPNOTSUPP, "Operation not supported"),
+  E(WSAEPFNOSUPPORT,  "Protocol family not supported"),
+  E(WSAEAFNOSUPPORT, "Address family not supported by protocol family"),
+  E(WSAEADDRINUSE, "Address already in use"),
+  E(WSAEADDRNOTAVAIL, "Cannot assign requested address"),
+  E(WSAENETDOWN, "Network is down"),
+  E(WSAENETUNREACH, "Network is unreachable"),
+  E(WSAENETRESET, "Network dropped connection on reset"),
+  E(WSAECONNABORTED, "Software caused connection abort"),
+  E(WSAECONNRESET, "Connection reset by peer"),
+  E(WSAENOBUFS, "No buffer space available"),
+  E(WSAEISCONN, "Socket is already connected"),
+  E(WSAENOTCONN, "Socket is not connected"),
+  E(WSAESHUTDOWN, "Cannot send after socket shutdown"),
+  E(WSAETIMEDOUT, "Connection timed out"),
+  E(WSAECONNREFUSED, "Connection refused"),
+  E(WSAEHOSTDOWN, "Host is down"),
+  E(WSAEHOSTUNREACH, "No route to host"),
+  E(WSAEPROCLIM, "Too many processes"),
+
+  /* Yes, some of these start with WSA, not WSAE. No, I don't know why. */
+  E(WSASYSNOTREADY, "Network subsystem is unavailable"),
+  E(WSAVERNOTSUPPORTED, "Winsock.dll out of range"),
+  E(WSANOTINITIALISED, "Successful WSAStartup not yet performed"),
+  E(WSAEDISCON, "Graceful shutdown now in progress"),
+#ifdef WSATYPE_NOT_FOUND
+  E(WSATYPE_NOT_FOUND, "Class type not found"),
+#endif
+  E(WSAHOST_NOT_FOUND, "Host not found"),
+  E(WSATRY_AGAIN, "Nonauthoritative host not found"),
+  E(WSANO_RECOVERY, "This is a nonrecoverable error"),
+  E(WSANO_DATA, "Valid name, no data record of requested type)"),
+
+  /* There are some more error codes whose numeric values are marked
+   * <b>OS dependent</b>. They start with WSA_, apparently for the same
+   * reason that practitioners of some craft traditions deliberately
+   * introduce imperfections into their baskets and rugs "to allow the
+   * evil spirits to escape."  If we catch them, then our binaries
+   * might not report consistent results across versions of Windows.
+   * Thus, I'm going to let them all fall through.
+   */
+  { -1, NULL },
+};
+#undef E
+/** Equivalent to strerror, but for windows socket errors. */
+const char *
+evutil_socket_error_to_string(int errcode)
+{
+  /* XXXX Is there really no built-in function to do this? */
+  int i;
+  for (i=0; windows_socket_errors[i].code >= 0; ++i) {
+    if (e == windows_socket_errors[i].code)
+      return windows_socket_errors[i].msg;
+  }
+  return strerror(e);
+}
+#endif
+
 int
 evutil_snprintf(char *buf, size_t buflen, const char *format, ...)
 {

http.c

@@ -1141,7 +1141,7 @@ evhttp_connection_cb(struct bufferevent *bufev, void *arg)
 	struct evhttp_connection *evcon = arg;
 	int error;
 	socklen_t errsz = sizeof(error);
-		
+
 	/* Check if the connection completed */
 	if (getsockopt(evcon->fd, SOL_SOCKET, SO_ERROR, (void*)&error,
 		       &errsz) == -1) {
@@ -1153,7 +1153,7 @@ evhttp_connection_cb(struct bufferevent *bufev, void *arg)
 	if (error) {
 		event_debug(("%s: connect failed for \"%s:%d\" on %d: %s",
 		    __func__, evcon->address, evcon->port, evcon->fd,
-			strerror(error)));
+			evutil_socket_error_to_string(error)));
 		goto cleanup;
 	}
 
@@ -1770,7 +1770,7 @@ evhttp_connection_connect(struct evhttp_connection *evcon)
 	}
 
 	if (socket_connect(evcon->fd, evcon->address, evcon->port) == -1) {
-		event_warn("%s: connection to \"%s\" failed",
+		event_sock_warn(evcon->fd, "%s: connection to \"%s\" failed",
 		    __func__, evcon->address);
 		EVUTIL_CLOSESOCKET(evcon->fd); evcon->fd = -1;
 		return (-1);
@@ -2340,7 +2340,7 @@ evhttp_bind_socket(struct evhttp *http, const char *address, ev_uint16_t port)
 		return (-1);
 
 	if (listen(fd, 128) == -1) {
-		event_warn("%s: listen", __func__);
+		event_sock_warn(fd, "%s: listen", __func__);
 		EVUTIL_CLOSESOCKET(fd);
 		return (-1);
 	}
@@ -2763,7 +2763,7 @@ evhttp_get_request(struct evhttp *http, evutil_socket_t fd,
 
 	evcon = evhttp_get_request_connection(http, fd, sa, salen);
 	if (evcon == NULL) {
-		event_warn("%s: cannot get connection on %d", __func__, fd);
+		event_sock_warn(fd, "%s: cannot get connection on %d", __func__, fd);
 		EVUTIL_CLOSESOCKET(fd);
 		return;
 	}
@@ -2860,8 +2860,8 @@ bind_socket_ai(struct addrinfo *ai, int reuse)
         /* Create listen socket */
         fd = socket(AF_INET, SOCK_STREAM, 0);
         if (fd == -1) {
-                event_warn("socket");
+			event_sock_warn(-1, "socket");
-                return (-1);
+			return (-1);
         }
 
         if (evutil_make_socket_nonblocking(fd) < 0)

include/event2/util.h

@@ -117,14 +117,28 @@ int evutil_make_socket_nonblocking(evutil_socket_t sock);
 #define EVUTIL_CLOSESOCKET(s) close(s)
 #endif
 
+/* Winsock handles socket errors differently from the rest of the world.
+ * Elsewhere, a socket error is like any other error and is stored in errno.
+ * But winsock functions require you to retrieve the error with a special
+ * function, and don't let you use strerror for the error codes.  And handling
+ * EWOULD block is ... different. */
+
 #ifdef WIN32
+/** Return the most recent socket error.  Not idempotent. */
 #define EVUTIL_SOCKET_ERROR() WSAGetLastError()
+/** Replace the most recent socket error with errcode */
 #define EVUTIL_SET_SOCKET_ERROR(errcode)		\
 	do { WSASetLastError(errcode); } while (0)
+/** Return the most recent socket error to occur on sock. */
+int evutil_socket_geterror(evutil_socket_t sock);
+/** Convert a socket error to a string. */
+const char *evutil_socket_error_to_string(int errcode);
 #else
 #define EVUTIL_SOCKET_ERROR() (errno)
 #define EVUTIL_SET_SOCKET_ERROR(errcode)		\
 		do { errno = (errcode); } while (0)
+#define evutil_socket_geterror(sock) (errno)
+#define evutil_socket_error_to_string(errcode) (strerror(errcode))
 #endif
 
 /*

log.c

@@ -62,7 +62,7 @@
 
 #include "log.h"
 
-static void _warn_helper(int severity, int log_errno, const char *fmt,
+static void _warn_helper(int severity, const char *errstr, const char *fmt,
                          va_list ap);
 static void event_log(int severity, const char *msg);
 
@@ -72,7 +72,7 @@ event_err(int eval, const char *fmt, ...)
 	va_list ap;
 	
 	va_start(ap, fmt);
-	_warn_helper(_EVENT_LOG_ERR, errno, fmt, ap);
+	_warn_helper(_EVENT_LOG_ERR, strerror(errno), fmt, ap);
 	va_end(ap);
 	exit(eval);
 }
@@ -83,7 +83,30 @@ event_warn(const char *fmt, ...)
 	va_list ap;
 	
 	va_start(ap, fmt);
-	_warn_helper(_EVENT_LOG_WARN, errno, fmt, ap);
+	_warn_helper(_EVENT_LOG_WARN, strerror(errno), fmt, ap);
+	va_end(ap);
+}
+
+void
+event_sock_err(int eval, evutil_socket_t sock, const char *fmt, ...)
+{
+	va_list ap;
+	int err = evutil_socket_geterror(sock);
+
+	va_start(ap, fmt);
+	_warn_helper(_EVENT_LOG_ERR, evutil_socket_error_to_string(err), fmt, ap);
+	va_end(ap);
+	exit(eval);
+}
+
+void
+event_sock_warn(int sock, const char *fmt, ...)
+{
+	va_list ap;
+	int err = evutil_socket_geterror(sock);
+
+	va_start(ap, fmt);
+	_warn_helper(_EVENT_LOG_WARN, evutil_socket_error_to_string(err), fmt, ap);
 	va_end(ap);
 }
 
@@ -93,7 +116,7 @@ event_errx(int eval, const char *fmt, ...)
 	va_list ap;
 	
 	va_start(ap, fmt);
-	_warn_helper(_EVENT_LOG_ERR, -1, fmt, ap);
+	_warn_helper(_EVENT_LOG_ERR, NULL, fmt, ap);
 	va_end(ap);
 	exit(eval);
 }
@@ -104,7 +127,7 @@ event_warnx(const char *fmt, ...)
 	va_list ap;
 	
 	va_start(ap, fmt);
-	_warn_helper(_EVENT_LOG_WARN, -1, fmt, ap);
+	_warn_helper(_EVENT_LOG_WARN, NULL, fmt, ap);
 	va_end(ap);
 }
 
@@ -114,7 +137,7 @@ event_msgx(const char *fmt, ...)
 	va_list ap;
 	
 	va_start(ap, fmt);
-	_warn_helper(_EVENT_LOG_MSG, -1, fmt, ap);
+	_warn_helper(_EVENT_LOG_MSG, NULL, fmt, ap);
 	va_end(ap);
 }
 
@@ -124,12 +147,12 @@ _event_debugx(const char *fmt, ...)
 	va_list ap;
 	
 	va_start(ap, fmt);
-	_warn_helper(_EVENT_LOG_DEBUG, -1, fmt, ap);
+	_warn_helper(_EVENT_LOG_DEBUG, NULL, fmt, ap);
 	va_end(ap);
 }
 
 static void
-_warn_helper(int severity, int log_errno, const char *fmt, va_list ap)
+_warn_helper(int severity, const char *errstr, const char *fmt, va_list ap)
 {
 	char buf[1024];
 	size_t len;
@@ -139,11 +162,10 @@ _warn_helper(int severity, int log_errno, const char *fmt, va_list ap)
 	else
 		buf[0] = '\0';
 
-	if (log_errno >= 0) {
+	if (errstr) {
 		len = strlen(buf);
 		if (len < sizeof(buf) - 3) {
-			evutil_snprintf(buf + len, sizeof(buf) - len, ": %s",
+			evutil_snprintf(buf + len, sizeof(buf) - len, ": %s", errstr);
-			    strerror(log_errno));
 		}
 	}
 

log.h

@@ -35,6 +35,8 @@
 
 void event_err(int eval, const char *fmt, ...) EV_CHECK_FMT(2,3);
 void event_warn(const char *fmt, ...) EV_CHECK_FMT(1,2);
+void event_sock_err(int eval, int sock, const char *fmt, ...) EV_CHECK_FMT(3,4);
+void event_sock_warn(int sock, const char *fmt, ...) EV_CHECK_FMT(2,3);
 void event_errx(int eval, const char *fmt, ...) EV_CHECK_FMT(2,3);
 void event_warnx(const char *fmt, ...) EV_CHECK_FMT(1,2);
 void event_msgx(const char *fmt, ...) EV_CHECK_FMT(1,2);

signal.c

@@ -82,7 +82,7 @@ evsignal_cb(evutil_socket_t fd, short what, void *arg)
 
 	n = recv(fd, signals, sizeof(signals), 0);
 	if (n == -1)
-		event_err(1, "%s: read", __func__);
+		event_sock_err(1, fd, "%s: read", __func__);
 }
 
 #ifdef HAVE_SETFD
@@ -106,7 +106,7 @@ evsignal_init(struct event_base *base)
 	 */
 	if (evutil_socketpair(
 		    AF_UNIX, SOCK_STREAM, 0, base->sig.ev_signal_pair) == -1)
-		event_err(1, "%s: socketpair", __func__);
+		event_sock_err(1, -1, "%s: socketpair", __func__);
 
 	FD_CLOSEONEXEC(base->sig.ev_signal_pair[0]);
 	FD_CLOSEONEXEC(base->sig.ev_signal_pair[1]);
@@ -278,6 +278,9 @@ static void
 evsignal_handler(int sig)
 {
 	int save_errno = errno;
+#ifdef WIN32
+	int socket_errno = EVUTIL_SOCKET_ERROR();
+#endif
 
 	if (evsignal_base == NULL) {
 		event_warn(
@@ -296,6 +299,9 @@ evsignal_handler(int sig)
 	/* Wake up our notification mechanism */
 	send(evsignal_base->sig.ev_signal_pair[0], "a", 1, 0);
 	errno = save_errno;
+#ifdef WIN32
+	EVUTIL_SET_SOCKET_ERRNO(socket_error);
+#endif
 }
 
 void