Portability: Fix assumption about read() and write() on connecting sockets

[adns.git] / src / event.c

diff --git a/src/event.c b/src/event.c
index 3dd927b6974fb675536676eff51a17a8162a319a..39b67b75ad6d025538d233f245e98ae1812c4660 100644 (file)
--- a/src/event.c
+++ b/src/event.c
@@ -339,7 +339,8 @@ int adns__pollfds(adns_state ads, struct pollfd pollfds_buf[MAX_POLLFDS]) {
 }
 
 int adns_processreadable(adns_state ads, int fd, const struct timeval *now) {
-  int want, dgramlen, r, i, udpaddrlen, serv, old_skip;
+  int want, dgramlen, r, i, serv, old_skip;
+  socklen_t udpaddrlen;
   byte udpbuf[DNS_MAXUDP];
   char addrbuf[ADNS_ADDR2TEXT_BUFLEN];
   struct udpsocket *udp;
@@ -443,6 +444,22 @@ int adns_processwriteable(adns_state ads, int fd, const struct timeval *now) {
     assert(ads->tcprecv.used==0);
     assert(ads->tcprecv_skip==0);
     for (;;) {
+      /* This function can be called even if the fd wasn't actually
+       * flagged as writeable.  For asynch tcp connect we have to
+       * actually use the writeability to tell us the connect has
+       * completed (or failed), so we need to double check. */
+      fd_set writeable;
+      struct timeval timeout = { 0,0 };
+      FD_ZERO(&writeable);
+      FD_SET(ads->tcpsocket,&writeable);
+      r= select(ads->tcpsocket+1,0,&writeable,0,&timeout);
+      if (r==0) break;
+      if (r<0) {
+       if (errno==EINTR) continue;
+       adns__tcp_broken(ads,"select","failed connecting writeability check");
+       r= 0; goto xit;
+      }
+      assert(FD_ISSET(ads->tcpsocket,&writeable));
       if (!adns__vbuf_ensure(&ads->tcprecv,1)) { r= ENOMEM; goto xit; }
       r= read(ads->tcpsocket,&ads->tcprecv.buf,1);
       if (r==0 || (r<0 && (errno==EAGAIN || errno==EWOULDBLOCK))) {