diff --git a/compat/winansi.c b/compat/winansi.c index 97d84a96ed..3c9ed3cfe0 100644 --- a/compat/winansi.c +++ b/compat/winansi.c @@ -6,9 +6,12 @@ #include "../git-compat-util.h" #include #include +#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 @@ -84,6 +87,7 @@ static void warn_if_raster_font(void) static int is_console(int fd) { CONSOLE_SCREEN_BUFFER_INFO sbi; + DWORD mode; HANDLE hcon; static int initialized = 0; @@ -98,9 +102,15 @@ static int is_console(int fd) return 0; /* check if its a handle to a console output screen buffer */ - if (!GetConsoleScreenBufferInfo(hcon, &sbi)) + if (!fd) { + if (!GetConsoleMode(hcon, &mode)) + return 0; + } else if (!GetConsoleScreenBufferInfo(hcon, &sbi)) return 0; + if (fd >= 0 && fd <= 2) + fd_is_interactive[fd] |= FD_CONSOLE; + /* initialize attributes */ if (!initialized) { console = hcon; @@ -462,76 +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 @@ -558,49 +542,33 @@ 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 = (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) @@ -611,6 +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 */ @@ -654,12 +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); }