Add cygwin wrapper for ExitProcess and TerminateProcess.

winsup/cygwin/external.cc

@@ -32,6 +32,7 @@ details. */
 #include <iptypes.h>
 
 child_info *get_cygwin_startup_info ();
+static void exit_process (UINT, bool) __attribute__((noreturn));
 
 static winpids pids;
 
@@ -161,6 +162,37 @@ sync_winenv ()
   free (envblock);
 }
 
+/*
+ * Cygwin-specific wrapper for win32 ExitProcess and TerminateProcess.
+ * It ensures that the correct exit code, derived from the specified
+ * status value, will be made available to this process's parent (if
+ * that parent is also a cygwin process). If useTerminateProcess is
+ * true, then TerminateProcess(GetCurrentProcess(),...) will be used;
+ * otherwise, ExitProcess(...) is called.
+ *
+ * Used by startup code for cygwin processes which is linked statically
+ * into applications, and is not part of the cygwin DLL -- which is why
+ * this interface is exposed. "Normal" programs should use ANSI exit(),
+ * ANSI abort(), or POSIX _exit(), rather than this function -- because
+ * calling ExitProcess or TerminateProcess, even through this wrapper,
+ * skips much of the cygwin process cleanup code.
+ */
+static void
+exit_process (UINT status, bool useTerminateProcess)
+{
+  pid_t pid = getpid ();
+  external_pinfo * ep = fillout_pinfo (pid, 1);
+  DWORD dwpid = ep ? ep->dwProcessId : pid;
+  pinfo p (pid, PID_MAP_RW);
+  if ((dwpid == GetCurrentProcessId()) && (p->pid == ep->pid))
+    p.set_exit_code ((DWORD)status);
+  if (useTerminateProcess)
+    TerminateProcess (GetCurrentProcess(), status);
+  /* avoid 'else' clause to silence warning */
+  ExitProcess (status);
+}
+
+
 extern "C" unsigned long
 cygwin_internal (cygwin_getinfo_types t, ...)
 {
@@ -375,6 +407,12 @@ cygwin_internal (cygwin_getinfo_types t, ...)
 	  seterrno(file, line);
 	}
 	break;
+      case CW_EXIT_PROCESS:
+	{
+	  UINT status = va_arg (arg, UINT);
+	  int useTerminateProcess = va_arg (arg, int);
+	  exit_process (status, !!useTerminateProcess); /* no return */
+	}
 
       default:
 	break;