From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
For over a year, Git for Windows has carried a patch that detects the
MSYS2 pseudo ttys used by Git for Windows' default Git Bash (i.e. a
terminal that is not backed by a Win32 Console).
This patch accesses internals that of a previous MSVC runtime that is no
longer valid in newer versions, therefore we needed a replacement for
that hack in order to be able to compile Git using recent Microsoft
Visual C++.
This patch back-ports that patch and makes even the MINGW (i.e.
GCC-compiled) Git use it.
As a side effect (which was the reason for the back-port), this patch
also fixes the previous misguided attempt to intercept isatty() so that
it handles character devices (such as /dev/null) as Git expects it.
Signed-off-by: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
---
compat/winansi.c | 191 +++++++++++++++++++++++--------------------------------
1 file changed, 78 insertions(+), 113 deletions(-)
diff --git a/compat/winansi.c b/compat/winansi.c
index 97a004b8ab..3bfad0d065 100644
--- a/compat/winansi.c
+++ b/compat/winansi.c
@@ -6,9 +6,12 @@
#include "../git-compat-util.h"
#include <wingdi.h>
#include <winreg.h>
+#include "win32.h"
-/* In this file, we actually want to use Windows' own isatty(). */
-#undef isatty
+static int fd_is_interactive[3] = { 0, 0, 0 };
+#define FD_CONSOLE 0x1
+#define FD_SWAPPED 0x2
+#define FD_MSYS 0x4
/*
ANSI codes used by git: m, K
@@ -105,6 +108,9 @@ static int is_console(int fd)
} else if (!GetConsoleScreenBufferInfo(hcon, &sbi))
return 0;
+ if (fd >=0 && fd <= 2)
+ fd_is_interactive[fd] |= FD_CONSOLE;
+
/* initialize attributes */
if (!initialized) {
console = hcon;
@@ -466,76 +472,50 @@ static HANDLE duplicate_handle(HANDLE hnd)
return hresult;
}
-
-/*
- * Make MSVCRT's internal file descriptor control structure accessible
- * so that we can tweak OS handles and flags directly (we need MSVCRT
- * to treat our pipe handle as if it were a console).
- *
- * We assume that the ioinfo structure (exposed by MSVCRT.dll via
- * __pioinfo) starts with the OS handle and the flags. The exact size
- * varies between MSVCRT versions, so we try different sizes until
- * toggling the FDEV bit of _pioinfo(1)->osflags is reflected in
- * isatty(1).
- */
-typedef struct {
- HANDLE osfhnd;
- char osflags;
-} ioinfo;
-
-extern __declspec(dllimport) ioinfo *__pioinfo[];
-
-static size_t sizeof_ioinfo = 0;
-
-#define IOINFO_L2E 5
-#define IOINFO_ARRAY_ELTS (1 << IOINFO_L2E)
-
-#define FPIPE 0x08
-#define FDEV 0x40
-
-static inline ioinfo* _pioinfo(int fd)
-{
- return (ioinfo*)((char*)__pioinfo[fd >> IOINFO_L2E] +
- (fd & (IOINFO_ARRAY_ELTS - 1)) * sizeof_ioinfo);
-}
-
-static int init_sizeof_ioinfo(void)
-{
- int istty, wastty;
- /* don't init twice */
- if (sizeof_ioinfo)
- return sizeof_ioinfo >= 256;
-
- sizeof_ioinfo = sizeof(ioinfo);
- wastty = isatty(1);
- while (sizeof_ioinfo < 256) {
- /* toggle FDEV flag, check isatty, then toggle back */
- _pioinfo(1)->osflags ^= FDEV;
- istty = isatty(1);
- _pioinfo(1)->osflags ^= FDEV;
- /* return if we found the correct size */
- if (istty != wastty)
- return 0;
- sizeof_ioinfo += sizeof(void*);
- }
- error("Tweaking file descriptors doesn't work with this MSVCRT.dll");
- return 1;
-}
-
static HANDLE swap_osfhnd(int fd, HANDLE new_handle)
{
- ioinfo *pioinfo;
- HANDLE old_handle;
-
- /* init ioinfo size if we haven't done so */
- if (init_sizeof_ioinfo())
- return INVALID_HANDLE_VALUE;
-
- /* get ioinfo pointer and change the handles */
- pioinfo = _pioinfo(fd);
- old_handle = pioinfo->osfhnd;
- pioinfo->osfhnd = new_handle;
- return old_handle;
+ /*
+ * Create a copy of the original handle associated with fd
+ * because the original will get closed when we dup2().
+ */
+ HANDLE handle = (HANDLE)_get_osfhandle(fd);
+ HANDLE duplicate = duplicate_handle(handle);
+
+ /* Create a temp fd associated with the already open "new_handle". */
+ int new_fd = _open_osfhandle((intptr_t)new_handle, O_BINARY);
+
+ assert((fd == 1) || (fd == 2));
+
+ /*
+ * Use stock dup2() to re-bind fd to the new handle. Note that
+ * this will implicitly close(1) and close both fd=1 and the
+ * originally associated handle. It will open a new fd=1 and
+ * call DuplicateHandle() on the handle associated with new_fd.
+ * It is because of this implicit close() that we created the
+ * copy of the original.
+ *
+ * Note that the OS can recycle HANDLE (numbers) just like it
+ * recycles fd (numbers), so we must update the cached value
+ * of "console". You can use GetFileType() to see that
+ * handle and _get_osfhandle(fd) may have the same number
+ * value, but they refer to different actual files now.
+ *
+ * Note that dup2() when given target := {0,1,2} will also
+ * call SetStdHandle(), so we don't need to worry about that.
+ */
+ dup2(new_fd, fd);
+ if (console == handle)
+ console = duplicate;
+ handle = INVALID_HANDLE_VALUE;
+
+ /* Close the temp fd. This explicitly closes "new_handle"
+ * (because it has been associated with it).
+ */
+ close(new_fd);
+
+ fd_is_interactive[fd] |= FD_SWAPPED;
+
+ return duplicate;
}
#ifdef DETECT_MSYS_TTY
@@ -562,49 +542,32 @@ static void detect_msys_tty(int fd)
name = nameinfo->Name.Buffer;
name[nameinfo->Name.Length / sizeof(*name)] = 0;
- /* check if this could be a MSYS2 pty pipe ('msys-XXXX-ptyN-XX') */
- if (!wcsstr(name, L"msys-") || !wcsstr(name, L"-pty"))
+ /*
+ * Check if this could be a MSYS2 pty pipe ('msys-XXXX-ptyN-XX')
+ * or a cygwin pty pipe ('cygwin-XXXX-ptyN-XX')
+ */
+ if ((!wcsstr(name, L"msys-") && !wcsstr(name, L"cygwin-")) ||
+ !wcsstr(name, L"-pty"))
return;
- /* init ioinfo size if we haven't done so */
- if (init_sizeof_ioinfo())
- return;
-
- /* set FDEV flag, reset FPIPE flag */
- _pioinfo(fd)->osflags &= ~FPIPE;
- _pioinfo(fd)->osflags |= FDEV;
+ fd_is_interactive[fd] |= FD_MSYS;
}
#endif
+/* Wrapper for isatty(). Most calls in the main git code
+ * call isatty(1 or 2) to see if the instance is interactive
+ * and should: be colored, show progress, paginate output.
+ * We lie and give results for what the descriptor WAS at
+ * startup (and ignore any pipe redirection we internally
+ * do).
+ */
+#undef isatty
int winansi_isatty(int fd)
{
- int res = isatty(fd);
-
- if (res) {
- /*
- * Make sure that /dev/null is not fooling Git into believing
- * that we are connected to a terminal, as "_isatty() returns a
- * nonzero value if the descriptor is associated with a
- * character device."; for more information, see
- *
- * https://msdn.microsoft.com/en-us/library/f4s0ddew.aspx
- */
- HANDLE handle = winansi_get_osfhandle(fd);
- if (fd == STDIN_FILENO) {
- DWORD dummy;
-
- if (!GetConsoleMode(handle, &dummy))
- res = 0;
- } else if (fd == STDOUT_FILENO || fd == STDERR_FILENO) {
- CONSOLE_SCREEN_BUFFER_INFO dummy;
-
- if (!GetConsoleScreenBufferInfo(handle, &dummy))
- res = 0;
- }
- }
-
- return res;
+ if (fd >=0 && fd <= 2)
+ return fd_is_interactive[fd] != 0;
+ return isatty(fd);
}
void winansi_init(void)
@@ -615,6 +578,10 @@ void winansi_init(void)
/* check if either stdout or stderr is a console output screen buffer */
con1 = is_console(1);
con2 = is_console(2);
+
+ /* Also compute console bit for fd 0 even though we don't need the result here. */
+ is_console(0);
+
if (!con1 && !con2) {
#ifdef DETECT_MSYS_TTY
/* check if stdin / stdout / stderr are MSYS2 pty pipes */
@@ -658,12 +625,10 @@ void winansi_init(void)
*/
HANDLE winansi_get_osfhandle(int fd)
{
- HANDLE hnd = (HANDLE) _get_osfhandle(fd);
- if (isatty(fd) && GetFileType(hnd) == FILE_TYPE_PIPE) {
- if (fd == 1 && hconsole1)
- return hconsole1;
- else if (fd == 2 && hconsole2)
- return hconsole2;
- }
- return hnd;
+ if (fd == 1 && (fd_is_interactive[1] & FD_SWAPPED))
+ return hconsole1;
+ if (fd == 2 && (fd_is_interactive[2] & FD_SWAPPED))
+ return hconsole2;
+
+ return (HANDLE)_get_osfhandle(fd);
}
--
2.11.0.rc3.windows.1