Curl_getconnectinfo: avoid checking if the connection is closed

It doesn't benefit us much as the connection could get closed at
any time, and also by checking we lose the ability to determine
if the socket was closed by reading zero bytes.

Reported-by: Michael Kaufmann
Closes https://github.com/curl/curl/pull/1134

diff --git a/lib/connect.c b/lib/connect.c
index f86c31d4d5417bfbe0390d966b2db0183754c635..284726ae3169a03bbd57647da11c6b8411fc867b 100644 (file)
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -1247,24 +1247,6 @@ curl_socket_t Curl_getconnectinfo(struct Curl_easy *data,
       /* only store this if the caller cares for it */
       *connp = c;
     sockfd = c->sock[FIRSTSOCKET];
-    /* we have a socket connected, let's determine if the server shut down */
-    /* determine if ssl */
-    if(c->ssl[FIRSTSOCKET].use) {
-      /* use the SSL context */
-      if(!Curl_ssl_check_cxn(c))
-        return CURL_SOCKET_BAD;   /* FIN received */
-    }
-/* Minix 3.1 doesn't support any flags on recv; just assume socket is OK */
-#ifdef MSG_PEEK
-    else if(sockfd != CURL_SOCKET_BAD) {
-      /* use the socket */
-      char buf;
-      if(recv((RECV_TYPE_ARG1)sockfd, (RECV_TYPE_ARG2)&buf,
-              (RECV_TYPE_ARG3)1, (RECV_TYPE_ARG4)MSG_PEEK) == 0) {
-        return CURL_SOCKET_BAD;   /* FIN received */
-      }
-    }
-#endif
   }
   else
     return CURL_SOCKET_BAD;
@@ -1272,6 +1254,33 @@ curl_socket_t Curl_getconnectinfo(struct Curl_easy *data,
   return sockfd;
 }
 
+/*
+ * Check if a connection seems to be alive.
+ */
+bool Curl_connalive(struct connectdata *conn)
+{
+  /* First determine if ssl */
+  if(conn->ssl[FIRSTSOCKET].use) {
+    /* use the SSL context */
+    if(!Curl_ssl_check_cxn(conn))
+      return false;   /* FIN received */
+  }
+/* Minix 3.1 doesn't support any flags on recv; just assume socket is OK */
+#ifdef MSG_PEEK
+  else if(conn->sock[FIRSTSOCKET] == CURL_SOCKET_BAD)
+    return false;
+  else {
+    /* use the socket */
+    char buf;
+    if(recv((RECV_TYPE_ARG1)conn->sock[FIRSTSOCKET], (RECV_TYPE_ARG2)&buf,
+            (RECV_TYPE_ARG3)1, (RECV_TYPE_ARG4)MSG_PEEK) == 0) {
+      return false;   /* FIN received */
+    }
+  }
+#endif
+  return true;
+}
+
 /*
  * Close a socket.
  *

diff --git a/lib/connect.h b/lib/connect.h
index 5e48eb6446809f8f0e7292fe735a41eefccf21d9..e01d1b35ee899fea2a6966b65e1cad558ebf8b9e 100644 (file)
--- a/lib/connect.h
+++ b/lib/connect.h
@@ -52,6 +52,11 @@ time_t Curl_timeleft(struct Curl_easy *data,
 curl_socket_t Curl_getconnectinfo(struct Curl_easy *data,
                                   struct connectdata **connp);
 
+/*
+ * Check if a connection seems to be alive.
+ */
+bool Curl_connalive(struct connectdata *conn);
+
 #ifdef USE_WINSOCK
 /* When you run a program that uses the Windows Sockets API, you may
    experience slow performance when you copy data to a TCP server.

diff --git a/lib/rtsp.c b/lib/rtsp.c
index c8484c44b225e22a43f8a493cc298968eda53dd7..65c6c3b05d9b9c6b7985f7bb2a95495c2cba5d34 100644 (file)
--- a/lib/rtsp.c
+++ b/lib/rtsp.c
@@ -140,7 +140,7 @@ static CURLcode rtsp_setup_connection(struct connectdata *conn)
  * want to block the application forever while receiving a stream. Therefore,
  * we cannot assume that an RTSP socket is dead just because it is readable.
  *
- * Instead, if it is readable, run Curl_getconnectinfo() to peek at the socket
+ * Instead, if it is readable, run Curl_connalive() to peek at the socket
  * and distinguish between closed and data.
  */
 bool Curl_rtsp_connisdead(struct connectdata *check)
@@ -157,12 +157,9 @@ bool Curl_rtsp_connisdead(struct connectdata *check)
     /* socket is in an error state */
     ret_val = TRUE;
   }
-  else if((sval & CURL_CSELECT_IN) && check->data) {
-    /* readable with no error. could be closed or could be alive but we can
-       only check if we have a proper Curl_easy for the connection */
-    curl_socket_t connectinfo = Curl_getconnectinfo(check->data, &check);
-    if(connectinfo != CURL_SOCKET_BAD)
-      ret_val = FALSE;
+  else if(sval & CURL_CSELECT_IN) {
+    /* readable with no error. could still be closed */
+    ret_val = !Curl_connalive(check);
   }
 
   return ret_val;