*** close IMAP socket ourselves instead of waiting for the server

*** this violates the RFC

some ms exchange versions and misconfigured tunnels just hang.

REFMAIL: <87czqj9xrw.fsf@vonfry.name>
REFMAIL: <CAC089cxhrYc+PyW-FGevaevQZ2GF98DBP25WVzUS7oEsMa73kg@mail.gmail.com>

src/drv_imap.c

@@ -168,9 +168,8 @@ union imap_store {
 		uint buffer_mem;  // Memory currently occupied by buffers in the queue
 
 		// Used during sequential operations like connect
-		enum { GreetingPending = 0, GreetingBad, GreetingOk, GreetingPreauth } greeting;
+		enum { GreetingPending = 0, GreetingOk, GreetingPreauth } greeting;
 		int expectBYE;  // LOGOUT is in progress
-		int expectEOF;  // received LOGOUT's OK or unsolicited BYE
 		int canceling;  // imap_cancel_cmds() is in progress
 		union {
 			void (*imap_open)( int sts, void *aux );
@@ -1759,7 +1758,6 @@ imap_socket_read( void *aux )
 			return;
 		}
 		if (cmd == (void *)~0) {
-			if (!ctx->expectEOF)
 			error( "IMAP error: unexpected EOF from %s\n", ctx->conn.name );
 			/* A clean shutdown sequence ends with bad_callback as well (see imap_cleanup()). */
 			break;
@@ -1796,14 +1794,10 @@ imap_socket_read( void *aux )
 				}
 			} else if (equals( arg, argl, "BYE", 3 )) {
 				if (!ctx->expectBYE) {
-					ctx->greeting = GreetingBad;
 					error( "IMAP error: unexpected BYE response: %s\n", cmd );
-					/* We just wait for the server to close the connection now. */
-					ctx->expectEOF = 1;
-					socket_expect_eof( &ctx->conn );
-				} else {
-					/* We still need to wait for the LOGOUT's tagged OK. */
+					break;
 				}
+				// We still need to wait for the LOGOUT's tagged OK.
 			} else if (ctx->greeting == GreetingPending) {
 				error( "IMAP error: bogus greeting response %s\n", arg );
 				break;
@@ -2085,14 +2079,9 @@ imap_cleanup( void )
 
 static void
 imap_cleanup_p2( imap_store_t *ctx,
-                 imap_cmd_t *cmd ATTR_UNUSED, int response )
+                 imap_cmd_t *cmd ATTR_UNUSED, int response ATTR_UNUSED )
 {
-	if (response == RESP_NO) {
 	imap_cancel_store( &ctx->gen );
-	} else if (response == RESP_OK) {
-		ctx->expectEOF = 1;
-		socket_expect_eof( &ctx->conn );
-	}
 }
 
 /******************* imap_open_store *******************/

src/socket.c

@@ -822,15 +822,6 @@ socket_expect_activity( conn_t *conn, int expect )
 		conf_wakeup( &conn->fd_timeout, expect ? conn->conf->timeout : -1 );
 }
 
-void
-socket_expect_eof( conn_t *sock )
-{
-#ifdef SSL_OP_IGNORE_UNEXPECTED_EOF  // implies HAVE_LIBSSL
-	if (sock->ssl)
-		SSL_set_options( sock->ssl, SSL_OP_IGNORE_UNEXPECTED_EOF );
-#endif
-}
-
 void
 socket_expect_bytes( conn_t *conn, uint len )
 {

src/socket.h

@@ -134,7 +134,6 @@ void socket_start_tls(conn_t *conn, void (*cb)( int ok, void *aux ) );
 void socket_start_deflate( conn_t *conn );
 void socket_close( conn_t *sock );
 void socket_expect_activity( conn_t *sock, int expect );
-void socket_expect_eof( conn_t *sock );
 void socket_expect_bytes( conn_t *sock, uint len );
 // Don't free return values. These functions never wait.
 char *socket_read( conn_t *conn, uint min_len, uint max_len, uint *out_len );