diff options
| -rw-r--r-- | Documentation/git.txt | 18 | ||||
| -rw-r--r-- | compat/mingw.c | 58 | ||||
| -rwxr-xr-x | t/t0001-init.sh | 12 |
3 files changed, 88 insertions, 0 deletions
diff --git a/Documentation/git.txt b/Documentation/git.txt index 7a1d629ca0..463b0eb0f5 100644 --- a/Documentation/git.txt +++ b/Documentation/git.txt @@ -709,6 +709,24 @@ of clones and fetches. the background which do not want to cause lock contention with other operations on the repository. Defaults to `1`. +`GIT_REDIRECT_STDIN`:: +`GIT_REDIRECT_STDOUT`:: +`GIT_REDIRECT_STDERR`:: + Windows-only: allow redirecting the standard input/output/error + handles to paths specified by the environment variables. This is + particularly useful in multi-threaded applications where the + canonical way to pass standard handles via `CreateProcess()` is + not an option because it would require the handles to be marked + inheritable (and consequently *every* spawned process would + inherit them, possibly blocking regular Git operations). The + primary intended use case is to use named pipes for communication + (e.g. `\\.\pipe\my-git-stdin-123`). ++ +Two special values are supported: `off` will simply close the +corresponding standard handle, and if `GIT_REDIRECT_STDERR` is +`2>&1`, standard error will be redirected to the same handle as +standard output. + Discussion[[Discussion]] ------------------------ diff --git a/compat/mingw.c b/compat/mingw.c index 8b6fa0db44..2d44d21aca 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -2139,6 +2139,62 @@ static char *wcstoutfdup_startup(char *buffer, const wchar_t *wcs, size_t len) return memcpy(malloc_startup(len), buffer, len); } +static void maybe_redirect_std_handle(const wchar_t *key, DWORD std_id, int fd, + DWORD desired_access, DWORD flags) +{ + DWORD create_flag = fd ? OPEN_ALWAYS : OPEN_EXISTING; + wchar_t buf[MAX_PATH]; + DWORD max = ARRAY_SIZE(buf); + HANDLE handle; + DWORD ret = GetEnvironmentVariableW(key, buf, max); + + if (!ret || ret >= max) + return; + + /* make sure this does not leak into child processes */ + SetEnvironmentVariableW(key, NULL); + if (!wcscmp(buf, L"off")) { + close(fd); + handle = GetStdHandle(std_id); + if (handle != INVALID_HANDLE_VALUE) + CloseHandle(handle); + return; + } + if (std_id == STD_ERROR_HANDLE && !wcscmp(buf, L"2>&1")) { + handle = GetStdHandle(STD_OUTPUT_HANDLE); + if (handle == INVALID_HANDLE_VALUE) { + close(fd); + handle = GetStdHandle(std_id); + if (handle != INVALID_HANDLE_VALUE) + CloseHandle(handle); + } else { + int new_fd = _open_osfhandle((intptr_t)handle, O_BINARY); + SetStdHandle(std_id, handle); + dup2(new_fd, fd); + /* do *not* close the new_fd: that would close stdout */ + } + return; + } + handle = CreateFileW(buf, desired_access, 0, NULL, create_flag, + flags, NULL); + if (handle != INVALID_HANDLE_VALUE) { + int new_fd = _open_osfhandle((intptr_t)handle, O_BINARY); + SetStdHandle(std_id, handle); + dup2(new_fd, fd); + close(new_fd); + } +} + +static void maybe_redirect_std_handles(void) +{ + maybe_redirect_std_handle(L"GIT_REDIRECT_STDIN", STD_INPUT_HANDLE, 0, + GENERIC_READ, FILE_ATTRIBUTE_NORMAL); + maybe_redirect_std_handle(L"GIT_REDIRECT_STDOUT", STD_OUTPUT_HANDLE, 1, + GENERIC_WRITE, FILE_ATTRIBUTE_NORMAL); + maybe_redirect_std_handle(L"GIT_REDIRECT_STDERR", STD_ERROR_HANDLE, 2, + GENERIC_WRITE, FILE_FLAG_NO_BUFFERING); +} + void mingw_startup(void) { int i, maxlen, argc; @@ -2146,6 +2202,8 @@ void mingw_startup(void) wchar_t **wenv, **wargv; _startupinfo si; + maybe_redirect_std_handles(); + /* get wide char arguments and environment */ si.newmode = 0; if (__wgetmainargs(&argc, &wargv, &wenv, _CRT_glob, &si) < 0) diff --git a/t/t0001-init.sh b/t/t0001-init.sh index 86c1a51654..c413bff9cf 100755 --- a/t/t0001-init.sh +++ b/t/t0001-init.sh @@ -453,4 +453,16 @@ test_expect_success 're-init from a linked worktree' ' ) ' +test_expect_success MINGW 'redirect std handles' ' + GIT_REDIRECT_STDOUT=output.txt git rev-parse --git-dir && + test .git = "$(cat output.txt)" && + test -z "$(GIT_REDIRECT_STDOUT=off git rev-parse --git-dir)" && + test_must_fail env \ + GIT_REDIRECT_STDOUT=output.txt \ + GIT_REDIRECT_STDERR="2>&1" \ + git rev-parse --git-dir --verify refs/invalid && + printf ".git\nfatal: Needed a single revision\n" >expect && + test_cmp expect output.txt +' + test_done |