@matheusbsbs / matheus-bagliano / commits / 51822653f5

Win32: reliably detect console pipe handles

As of "Win32: Thread-safe windows console output", child processes may print to the console even if stdout has been redirected to a file. E.g.: git config tar.cat.command "cat" git archive -o test.cat HEAD Detecting whether stdout / stderr point to our console pipe is currently based on the assumption that OS HANDLE values are never reused. This is apparently not true if stdout / stderr is replaced via dup2() (as in builtin/archive.c:17). Instead of comparing handle values, check if the file descriptor isatty() backed by a pipe OS handle. This is only possible by swapping the handles in MSVCRT's internal data structures, as we do in winansi_init(). Reported-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Karsten Blees committed Jun 14, 2014 at 00:09 UTC 51822653f58e6b9b6119f560ff864813fbde81ba

1 file changed +7 -18

compat/winansi.c

+7 -18

@@ -20,7 +20,6 @@ static WORD attr;

20 static int negative;

21 static int non_ascii_used = 0;

22 static HANDLE hthread, hread, hwrite;

23 -static HANDLE hwrite1 = INVALID_HANDLE_VALUE, hwrite2 = INVALID_HANDLE_VALUE;

23 static HANDLE hconsole1, hconsole2;

25 #ifdef __MINGW32__

@@ -435,10 +434,6 @@ static void winansi_exit(void)

434 WaitForSingleObject(hthread, INFINITE);

435

436 /* cleanup handles... */

438 - if (hwrite1 != INVALID_HANDLE_VALUE)

439 - CloseHandle(hwrite1);

440 - if (hwrite2 != INVALID_HANDLE_VALUE)

441 - CloseHandle(hwrite2);

437 CloseHandle(hwrite);

438 CloseHandle(hthread);

439 }

@@ -565,14 +560,9 @@ void winansi_init(void)

560

561 /* redirect stdout / stderr to the pipe */

562 if (con1)

568 - hconsole1 = swap_osfhnd(1, hwrite1 = duplicate_handle(hwrite));

563 + hconsole1 = swap_osfhnd(1, duplicate_handle(hwrite));

564 if (con2)

570 - hconsole2 = swap_osfhnd(2, hwrite2 = duplicate_handle(hwrite));

571 -}

572 -

573 -static int is_same_handle(HANDLE hnd, int fd)

574 -{

575 - return hnd != INVALID_HANDLE_VALUE && hnd == (HANDLE) _get_osfhandle(fd);

565 + hconsole2 = swap_osfhnd(2, duplicate_handle(hwrite));

566 }

567

568 /*

@@ -581,10 +571,9 @@ static int is_same_handle(HANDLE hnd, int fd)

571 */

572 HANDLE winansi_get_osfhandle(int fd)

573 {

584 - if (fd == 1 && is_same_handle(hwrite1, 1))

585 - return hconsole1;

586 - else if (fd == 2 && is_same_handle(hwrite2, 2))

587 - return hconsole2;

588 - else

589 - return (HANDLE) _get_osfhandle(fd);

574 + HANDLE hnd = (HANDLE) _get_osfhandle(fd);

575 + if ((fd == 1 || fd == 2) && isatty(fd)

576 + && GetFileType(hnd) == FILE_TYPE_PIPE)

577 + return (fd == 1) ? hconsole1 : hconsole2;

578 + return hnd;

579 }