Windows: simplify the pipe(2) implementation

Our implementation of pipe() must create non-inheritable handles for the
reason that when a child process is started, there is no opportunity to
close the unneeded pipe ends in the child (on POSIX this is done between
fork() and exec()).

Previously, we used the _pipe() function provided by Microsoft's C runtime
(which creates inheritable handles) and then turned the handles into
non-inheritable handles using the DuplicateHandle() API.

Simplify the procedure by using the CreatePipe() API, which can create
non-inheritable handles right from the beginning.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/compat/mingw.c b/compat/mingw.c
index 2afc978dfd2dfd74ccb481af6e9618b71a7e3caf..162d1ff283e5e13adb108b1c65d7017ebb80cb55 100644 (file)
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -299,46 +299,25 @@ int gettimeofday(struct timeval *tv, void *tz)
 
 int pipe(int filedes[2])
 {
-       int fd;
-       HANDLE h[2], parent;
-
-       if (_pipe(filedes, 8192, 0) < 0)
-               return -1;
+       HANDLE h[2];
 
-       parent = GetCurrentProcess();
-
-       if (!DuplicateHandle (parent, (HANDLE)_get_osfhandle(filedes[0]),
-                       parent, &h[0], 0, FALSE, DUPLICATE_SAME_ACCESS)) {
-               close(filedes[0]);
-               close(filedes[1]);
-               return -1;
-       }
-       if (!DuplicateHandle (parent, (HANDLE)_get_osfhandle(filedes[1]),
-                       parent, &h[1], 0, FALSE, DUPLICATE_SAME_ACCESS)) {
-               close(filedes[0]);
-               close(filedes[1]);
-               CloseHandle(h[0]);
+       /* this creates non-inheritable handles */
+       if (!CreatePipe(&h[0], &h[1], NULL, 8192)) {
+               errno = err_win_to_posix(GetLastError());
                return -1;
        }
-       fd = _open_osfhandle((int)h[0], O_NOINHERIT);
-       if (fd < 0) {
-               close(filedes[0]);
-               close(filedes[1]);
+       filedes[0] = _open_osfhandle((int)h[0], O_NOINHERIT);
+       if (filedes[0] < 0) {
                CloseHandle(h[0]);
                CloseHandle(h[1]);
                return -1;
        }
-       close(filedes[0]);
-       filedes[0] = fd;
-       fd = _open_osfhandle((int)h[1], O_NOINHERIT);
-       if (fd < 0) {
+       filedes[1] = _open_osfhandle((int)h[1], O_NOINHERIT);
+       if (filedes[0] < 0) {
                close(filedes[0]);
-               close(filedes[1]);
                CloseHandle(h[1]);
                return -1;
        }
-       close(filedes[1]);
-       filedes[1] = fd;
        return 0;
 }