Make TCP connect() handle EINTR correctly

According to the POSIX standard, if connect() is interrupted by a
signal that is caught while blocked waiting to establish a connection,
connect() shall fail and set errno to EINTR, but the connection
request shall not be aborted, and the connection shall be established
asynchronously.

If asynchronous connection was successfully established after EINTR
and before the next connection attempt, OS returns EISCONN that was
handled as an error before. This behavior is fixed now and we handle
it as success.

The problem affects MacOS users: Linux doesn't return EISCONN in this
case, Windows connect() can not be interrupted without an old-fashoin
WSACancelBlockingCall function that is not used in the library.
So current solution gives connect() as OS specific implementation.

1 files changed, 7 insertions, 5 deletions

diff --git a/library/std/src/sys/windows/net.rs b/library/std/src/sys/windows/net.rs
index 4b7115f97c5..c29b863665f 100644
--- a/library/std/src/sys/windows/net.rs
+++ b/library/std/src/sys/windows/net.rs
@@ -140,13 +140,15 @@ impl Socket {
         }
     }
 
+    pub fn connect(&self, addr: &SocketAddr) -> io::Result<()> {
+        let (addr, len) = addr.into_inner();
+        let result = unsafe { c::connect(self.as_raw(), addr.as_ptr(), len) };
+        cvt(result).map(drop)
+    }
+
     pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Result<()> {
         self.set_nonblocking(true)?;
-        let result = {
-            let (addr, len) = addr.into_inner();
-            let result = unsafe { c::connect(self.as_raw(), addr.as_ptr(), len) };
-            cvt(result).map(drop)
-        };
+        let result = self.connect(addr);
         self.set_nonblocking(false)?;
 
         match result {