Fixed sshd process not ending when sftp-server and the shell ended

NoMachine did not finish coding child process ending detection logic.
Added the needed code so that child process handle is added to the
handles that WaitForMultipleObjects() waits for in nomachine select()
implementation in socket.c. Otherwise select() would be stuck in
read/write dectection even when the process of interest has exited.

Author: quamrulmina

contrib/win32/win32compat/socket.c

@@ -1986,6 +1986,13 @@ int cleanSelectThread(int thread_no)
   return 1;
 }
 
+// Add a Child process to be added to select mux so thyat we know when it has exited
+HANDLE ChildToWatch = NULL;
+int WSHELPAddChildToWatch ( HANDLE processtowatch)
+{
+	ChildToWatch = processtowatch;
+	return 0;
+}
 
 int WSHELPselect(int fds, fd_set* readsfds, fd_set* writesfds,
                      fd_set* exceptsfds, const struct timeval* timeout)
@@ -2288,6 +2295,12 @@ int WSHELPselect(int fds, fd_set* readsfds, fd_set* writesfds,
   DBG_MSG("WSHELPselect(fds = %d) : Waiting for signal from threads...\n", fds);
 
   DBG_MSG("i_sem = %d\n", i_sem);
+ 
+  // add a child process handle to the mux if it was registered
+  if ( ChildToWatch ) {
+	semaphores[i_sem] = ChildToWatch ;
+	i_sem++;
+  }
 
   dwWaitResult = WaitForMultipleObjects(i_sem, semaphores, FALSE, ms);
 
@@ -2536,8 +2549,8 @@ int WSHELPwrite(int sfd, const char *buf, unsigned int max)
 
         if (sfd != 2)
         {
-          error("write to socket sfd [%d] failed with error code [%d]",
-                    sfd, GetLastError());
+          //error("write to socket sfd [%d] failed with error code [%d]",
+          //          sfd, GetLastError());
 
           DBG_MSG("<- WSHELPwrite(sfd = %d, ret = -1)...\n", sfd);
         }

session.c

@@ -834,6 +834,10 @@ do_exec_no_pty(Session *s, const char *command)
 
   s -> pid = pi.hProcess;
   s -> processId = pi.dwProcessId;
+  
+  // Add the child process created to select mux so that during our select data call we know if the process has exited
+  int WSHELPAddChildToWatch ( HANDLE processtowatch);
+  WSHELPAddChildToWatch ( pi.hProcess);
 
   /* 
    * Set interactive/non-interactive mode.