MINOR: protocol: add a ->drain() function at the connection control layer
This is what we need to drain pending incoming data from an connection.
The code was taken from conn_sock_drain() without the connection-specific
stuff. It still takes a connection for now for API simplicity.
diff --git a/src/proto_sockpair.c b/src/proto_sockpair.c
index 7124f56..9c16b2b 100644
--- a/src/proto_sockpair.c
+++ b/src/proto_sockpair.c
@@ -77,6 +77,7 @@
.ctrl_init = sock_conn_ctrl_init,
.ctrl_close = sock_conn_ctrl_close,
.connect = sockpair_connect_server,
+ .drain = sock_drain,
/* binding layer */
/* Note: suspend/resume not supported */
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index 4a5e9c2..dcc524d 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -67,6 +67,7 @@
.ctrl_init = sock_conn_ctrl_init,
.ctrl_close = sock_conn_ctrl_close,
.connect = tcp_connect_server,
+ .drain = sock_drain,
/* binding layer */
.rx_suspend = tcp_suspend_receiver,
@@ -106,6 +107,7 @@
.ctrl_init = sock_conn_ctrl_init,
.ctrl_close = sock_conn_ctrl_close,
.connect = tcp_connect_server,
+ .drain = sock_drain,
/* binding layer */
.rx_suspend = tcp_suspend_receiver,
diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index 1c6ea77..9b1fc38 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -63,6 +63,7 @@
.ctrl_init = sock_conn_ctrl_init,
.ctrl_close = sock_conn_ctrl_close,
.connect = uxst_connect_server,
+ .drain = sock_drain,
/* binding layer */
.rx_suspend = uxst_suspend_receiver,
diff --git a/src/sock.c b/src/sock.c
index 5a072f0..cd1e3ff 100644
--- a/src/sock.c
+++ b/src/sock.c
@@ -819,6 +819,59 @@
}
}
+/* Drains possibly pending incoming data on the file descriptor attached to the
+ * connection. This is used to know whether we need to disable lingering on
+ * close. Returns non-zero if it is safe to close without disabling lingering,
+ * otherwise zero.
+ */
+int sock_drain(struct connection *conn)
+{
+ int turns = 2;
+ int fd = conn->handle.fd;
+ int len;
+
+ if (fdtab[fd].ev & (FD_POLL_ERR|FD_POLL_HUP))
+ goto shut;
+
+ if (!fd_recv_ready(fd))
+ return 0;
+
+ /* no drain function defined, use the generic one */
+
+ while (turns) {
+#ifdef MSG_TRUNC_CLEARS_INPUT
+ len = recv(fd, NULL, INT_MAX, MSG_DONTWAIT | MSG_NOSIGNAL | MSG_TRUNC);
+ if (len == -1 && errno == EFAULT)
+#endif
+ len = recv(fd, trash.area, trash.size, MSG_DONTWAIT | MSG_NOSIGNAL);
+
+ if (len == 0)
+ goto shut;
+
+ if (len < 0) {
+ if (errno == EAGAIN) {
+ /* connection not closed yet */
+ fd_cant_recv(fd);
+ break;
+ }
+ if (errno == EINTR) /* oops, try again */
+ continue;
+ /* other errors indicate a dead connection, fine. */
+ goto shut;
+ }
+ /* OK we read some data, let's try again once */
+ turns--;
+ }
+
+ /* some data are still present, give up */
+ return 0;
+
+ shut:
+ /* we're certain the connection was shut down */
+ fdtab[fd].linger_risk = 0;
+ return 1;
+}
+
/*
* Local variables:
* c-indent-level: 8