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mingw: replace isatty() hack

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Git for Windows has carried a patch that depended on internals
of MSVC runtime, but it does not work correctly with recent MSVC
runtime. A replacement was written originally for compiling
with VC++. The patch in this message is a backport of that
replacement, and it also fixes the previous attempt to make
isatty() tell that /dev/null is *not* an interactive terminal.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Tested-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff Hostetler 2016-12-22 18:09:23 +01:00 committed by Junio C Hamano
parent 86924838e3
commit a9b8a09c3c
1 changed files with 71 additions and 109 deletions
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180
compat/winansi.c
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@ -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;
/*
* 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);
/* init ioinfo size if we haven't done so */
if (init_sizeof_ioinfo())
return INVALID_HANDLE_VALUE;
/* Create a temp fd associated with the already open "new_handle". */
int new_fd = _open_osfhandle((intptr_t)new_handle, O_BINARY);
/* get ioinfo pointer and change the handles */
pioinfo = _pioinfo(fd);
old_handle = pioinfo->osfhnd;
pioinfo->osfhnd = new_handle;
return old_handle;
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
@ -570,45 +550,25 @@ static void detect_msys_tty(int fd)
!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 = (HANDLE)_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)
@ -619,6 +579,10 @@ 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 */
@ -662,12 +626,10 @@ 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);
}