[PATCH 7/6] Win32: reliably detect console pipe handles
- From
Karsten Blees <karsten.blees@gmail.com>
- Date
- Jun 13, 2014, 22:09 UTC
- Message-ID
- <539B7682.7070308@gmail.com>
- In-Reply-To
- <539A95F1.9030900@kdbg.org>
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> ---
Thanks for reporting this.
The fix applies on top of [6/6] Win32: fix broken pipe detection (should probably not be squashed, as its obviously not as well tested as the rest of the series).
Cheers, Karsten
compat/winansi.c | 25 +++++++------------------ 1 file changed, 7 insertions(+), 18 deletions(-)
diff --git a/compat/winansi.c b/compat/winansi.c index f96d5c2..efc5bb3 100644 --- a/compat/winansi.c +++ b/compat/winansi.c @@ -20,7 +20,6 @@ static WORD attr; static int negative; static int non_ascii_used = 0; static HANDLE hthread, hread, hwrite; -static HANDLE hwrite1 = INVALID_HANDLE_VALUE, hwrite2 = INVALID_HANDLE_VALUE; static HANDLE hconsole1, hconsole2; #ifdef __MINGW32__ @@ -435,10 +434,6 @@ static void winansi_exit(void) WaitForSingleObject(hthread, INFINITE); /* cleanup handles... */ - if (hwrite1 != INVALID_HANDLE_VALUE) - CloseHandle(hwrite1); - if (hwrite2 != INVALID_HANDLE_VALUE) - CloseHandle(hwrite2); CloseHandle(hwrite); CloseHandle(hthread); } @@ -565,14 +560,9 @@ void winansi_init(void) /* redirect stdout / stderr to the pipe */ if (con1) - hconsole1 = swap_osfhnd(1, hwrite1 = duplicate_handle(hwrite)); + hconsole1 = swap_osfhnd(1, duplicate_handle(hwrite)); if (con2) - hconsole2 = swap_osfhnd(2, hwrite2 = duplicate_handle(hwrite)); -} - -static int is_same_handle(HANDLE hnd, int fd) -{ - return hnd != INVALID_HANDLE_VALUE && hnd == (HANDLE) _get_osfhandle(fd); + hconsole2 = swap_osfhnd(2, duplicate_handle(hwrite)); } /* @@ -581,10 +571,9 @@ static int is_same_handle(HANDLE hnd, int fd) */ HANDLE winansi_get_osfhandle(int fd) { - if (fd == 1 && is_same_handle(hwrite1, 1)) - return hconsole1; - else if (fd == 2 && is_same_handle(hwrite2, 2)) - return hconsole2; - else - return (HANDLE) _get_osfhandle(fd); + HANDLE hnd = (HANDLE) _get_osfhandle(fd); + if ((fd == 1 || fd == 2) && isatty(fd) + && GetFileType(hnd) == FILE_TYPE_PIPE) + return (fd == 1) ? hconsole1 : hconsole2; + return hnd; }
-- 1.9.3.10.ge3256ea