1 files changed, 337 insertions, 149 deletions

diff --git a/compat/mingw.c b/compat/mingw.c
index 70f3191a4f..858ca14a57 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -6,6 +6,8 @@
 #include "../run-command.h"
 #include "../cache.h"
 
+#define HCAST(type, handle) ((type)(intptr_t)handle)
+
 static const int delay[] = { 0, 1, 10, 20, 40 };
 
 int err_win_to_posix(DWORD winerr)
@@ -284,6 +286,49 @@ int mingw_rmdir(const char *pathname)
 	return ret;
 }
 
+static inline int needs_hiding(const char *path)
+{
+	const char *basename;
+
+	if (hide_dotfiles == HIDE_DOTFILES_FALSE)
+		return 0;
+
+	/* We cannot use basename(), as it would remove trailing slashes */
+	mingw_skip_dos_drive_prefix((char **)&path);
+	if (!*path)
+		return 0;
+
+	for (basename = path; *path; path++)
+		if (is_dir_sep(*path)) {
+			do {
+				path++;
+			} while (is_dir_sep(*path));
+			/* ignore trailing slashes */
+			if (*path)
+				basename = path;
+		}
+
+	if (hide_dotfiles == HIDE_DOTFILES_TRUE)
+		return *basename == '.';
+
+	assert(hide_dotfiles == HIDE_DOTFILES_DOTGITONLY);
+	return !strncasecmp(".git", basename, 4) &&
+		(!basename[4] || is_dir_sep(basename[4]));
+}
+
+static int set_hidden_flag(const wchar_t *path, int set)
+{
+	DWORD original = GetFileAttributesW(path), modified;
+	if (set)
+		modified = original | FILE_ATTRIBUTE_HIDDEN;
+	else
+		modified = original & ~FILE_ATTRIBUTE_HIDDEN;
+	if (original == modified || SetFileAttributesW(path, modified))
+		return 0;
+	errno = err_win_to_posix(GetLastError());
+	return -1;
+}
+
 int mingw_mkdir(const char *path, int mode)
 {
 	int ret;
@@ -291,15 +336,49 @@ int mingw_mkdir(const char *path, int mode)
 	if (xutftowcs_path(wpath, path) < 0)
 		return -1;
 	ret = _wmkdir(wpath);
+	if (!ret && needs_hiding(path))
+		return set_hidden_flag(wpath, 1);
 	return ret;
 }
 
+static int mingw_open_append(wchar_t const *wfilename, int oflags, ...)
+{
+	HANDLE handle;
+	int fd;
+	DWORD create = (oflags & O_CREAT) ? OPEN_ALWAYS : OPEN_EXISTING;
+
+	/* only these flags are supported */
+	if ((oflags & ~O_CREAT) != (O_WRONLY | O_APPEND))
+		return errno = ENOSYS, -1;
+
+	/*
+	 * FILE_SHARE_WRITE is required to permit child processes
+	 * to append to the file.
+	 */
+	handle = CreateFileW(wfilename, FILE_APPEND_DATA,
+			FILE_SHARE_WRITE | FILE_SHARE_READ,
+			NULL, create, FILE_ATTRIBUTE_NORMAL, NULL);
+	if (handle == INVALID_HANDLE_VALUE)
+		return errno = err_win_to_posix(GetLastError()), -1;
+	/*
+	 * No O_APPEND here, because the CRT uses it only to reset the
+	 * file pointer to EOF on write(); but that is not necessary
+	 * for a file created with FILE_APPEND_DATA.
+	 */
+	fd = _open_osfhandle((intptr_t)handle, O_BINARY);
+	if (fd < 0)
+		CloseHandle(handle);
+	return fd;
+}
+
 int mingw_open (const char *filename, int oflags, ...)
 {
+	typedef int (*open_fn_t)(wchar_t const *wfilename, int oflags, ...);
 	va_list args;
 	unsigned mode;
 	int fd;
 	wchar_t wfilename[MAX_PATH];
+	open_fn_t open_fn;
 
 	va_start(args, oflags);
 	mode = va_arg(args, int);
@@ -308,15 +387,35 @@ int mingw_open (const char *filename, int oflags, ...)
 	if (filename && !strcmp(filename, "/dev/null"))
 		filename = "nul";
 
+	if (oflags & O_APPEND)
+		open_fn = mingw_open_append;
+	else
+		open_fn = _wopen;
+
 	if (xutftowcs_path(wfilename, filename) < 0)
 		return -1;
-	fd = _wopen(wfilename, oflags, mode);
+	fd = open_fn(wfilename, oflags, mode);
 
 	if (fd < 0 && (oflags & O_ACCMODE) != O_RDONLY && errno == EACCES) {
 		DWORD attrs = GetFileAttributesW(wfilename);
 		if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY))
 			errno = EISDIR;
 	}
+	if ((oflags & O_CREAT) && needs_hiding(filename)) {
+		/*
+		 * Internally, _wopen() uses the CreateFile() API which errors
+		 * out with an ERROR_ACCESS_DENIED if CREATE_ALWAYS was
+		 * specified and an already existing file's attributes do not
+		 * match *exactly*. As there is no mode or flag we can set that
+		 * would correspond to FILE_ATTRIBUTE_HIDDEN, let's just try
+		 * again *without* the O_CREAT flag (that corresponds to the
+		 * CREATE_ALWAYS flag of CreateFile()).
+		 */
+		if (fd < 0 && errno == EACCES)
+			fd = open_fn(wfilename, oflags & ~O_CREAT, mode);
+		if (fd >= 0 && set_hidden_flag(wfilename, 1))
+			warning("could not mark '%s' as hidden.", filename);
+	}
 	return fd;
 }
 
@@ -348,6 +447,7 @@ int mingw_fgetc(FILE *stream)
 #undef fopen
 FILE *mingw_fopen (const char *filename, const char *otype)
 {
+	int hide = needs_hiding(filename);
 	FILE *file;
 	wchar_t wfilename[MAX_PATH], wotype[4];
 	if (filename && !strcmp(filename, "/dev/null"))
@@ -355,12 +455,21 @@ FILE *mingw_fopen (const char *filename, const char *otype)
 	if (xutftowcs_path(wfilename, filename) < 0 ||
 		xutftowcs(wotype, otype, ARRAY_SIZE(wotype)) < 0)
 		return NULL;
+	if (hide && !access(filename, F_OK) && set_hidden_flag(wfilename, 0)) {
+		error("could not unhide %s", filename);
+		return NULL;
+	}
 	file = _wfopen(wfilename, wotype);
+	if (!file && GetLastError() == ERROR_INVALID_NAME)
+		errno = ENOENT;
+	if (file && hide && set_hidden_flag(wfilename, 1))
+		warning("could not mark '%s' as hidden.", filename);
 	return file;
 }
 
 FILE *mingw_freopen (const char *filename, const char *otype, FILE *stream)
 {
+	int hide = needs_hiding(filename);
 	FILE *file;
 	wchar_t wfilename[MAX_PATH], wotype[4];
 	if (filename && !strcmp(filename, "/dev/null"))
@@ -368,7 +477,13 @@ FILE *mingw_freopen (const char *filename, const char *otype, FILE *stream)
 	if (xutftowcs_path(wfilename, filename) < 0 ||
 		xutftowcs(wotype, otype, ARRAY_SIZE(wotype)) < 0)
 		return NULL;
+	if (hide && !access(filename, F_OK) && set_hidden_flag(wfilename, 0)) {
+		error("could not unhide %s", filename);
+		return NULL;
+	}
 	file = _wfreopen(wfilename, wotype, stream);
+	if (file && hide && set_hidden_flag(wfilename, 1))
+		warning("could not mark '%s' as hidden.", filename);
 	return file;
 }
 
@@ -394,6 +509,23 @@ int mingw_fflush(FILE *stream)
 	return ret;
 }
 
+#undef write
+ssize_t mingw_write(int fd, const void *buf, size_t len)
+{
+	ssize_t result = write(fd, buf, len);
+
+	if (result < 0 && errno == EINVAL && buf) {
+		/* check if fd is a pipe */
+		HANDLE h = (HANDLE) _get_osfhandle(fd);
+		if (GetFileType(h) == FILE_TYPE_PIPE)
+			errno = EPIPE;
+		else
+			errno = EINVAL;
+	}
+
+	return result;
+}
+
 int mingw_access(const char *filename, int mode)
 {
 	wchar_t wfilename[MAX_PATH];
@@ -435,6 +567,39 @@ static inline time_t filetime_to_time_t(const FILETIME *ft)
 	return (time_t)(filetime_to_hnsec(ft) / 10000000);
 }
 
+/**
+ * Verifies that safe_create_leading_directories() would succeed.
+ */
+static int has_valid_directory_prefix(wchar_t *wfilename)
+{
+	int n = wcslen(wfilename);
+
+	while (n > 0) {
+		wchar_t c = wfilename[--n];
+		DWORD attributes;
+
+		if (!is_dir_sep(c))
+			continue;
+
+		wfilename[n] = L'\0';
+		attributes = GetFileAttributesW(wfilename);
+		wfilename[n] = c;
+		if (attributes == FILE_ATTRIBUTE_DIRECTORY ||
+				attributes == FILE_ATTRIBUTE_DEVICE)
+			return 1;
+		if (attributes == INVALID_FILE_ATTRIBUTES)
+			switch (GetLastError()) {
+			case ERROR_PATH_NOT_FOUND:
+				continue;
+			case ERROR_FILE_NOT_FOUND:
+				/* This implies parent directory exists. */
+				return 1;
+			}
+		return 0;
+	}
+	return 1;
+}
+
 /* We keep the do_lstat code in a separate function to avoid recursion.
  * When a path ends with a slash, the stat will fail with ENOENT. In
  * this case, we strip the trailing slashes and stat again.
@@ -495,6 +660,12 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf)
 	case ERROR_NOT_ENOUGH_MEMORY:
 		errno = ENOMEM;
 		break;
+	case ERROR_PATH_NOT_FOUND:
+		if (!has_valid_directory_prefix(wfilename)) {
+			errno = ENOTDIR;
+			break;
+		}
+		/* fallthru */
 	default:
 		errno = ENOENT;
 		break;
@@ -627,6 +798,17 @@ revert_attrs:
 	return rc;
 }
 
+#undef strftime
+size_t mingw_strftime(char *s, size_t max,
+		      const char *format, const struct tm *tm)
+{
+	size_t ret = strftime(s, max, format, tm);
+
+	if (!ret && errno == EINVAL)
+		die("invalid strftime format: '%s'", format);
+	return ret;
+}
+
 unsigned int sleep (unsigned int seconds)
 {
 	Sleep(seconds*1000);
@@ -674,14 +856,14 @@ int pipe(int filedes[2])
 		errno = err_win_to_posix(GetLastError());
 		return -1;
 	}
-	filedes[0] = _open_osfhandle((int)h[0], O_NOINHERIT);
+	filedes[0] = _open_osfhandle(HCAST(int, h[0]), O_NOINHERIT);
 	if (filedes[0] < 0) {
 		CloseHandle(h[0]);
 		CloseHandle(h[1]);
 		return -1;
 	}
-	filedes[1] = _open_osfhandle((int)h[1], O_NOINHERIT);
-	if (filedes[0] < 0) {
+	filedes[1] = _open_osfhandle(HCAST(int, h[1]), O_NOINHERIT);
+	if (filedes[1] < 0) {
 		close(filedes[0]);
 		CloseHandle(h[1]);
 		return -1;
@@ -705,15 +887,12 @@ struct tm *localtime_r(const time_t *timep, struct tm *result)
 
 char *mingw_getcwd(char *pointer, int len)
 {
-	int i;
 	wchar_t wpointer[MAX_PATH];
 	if (!_wgetcwd(wpointer, ARRAY_SIZE(wpointer)))
 		return NULL;
 	if (xwcstoutf(pointer, wpointer, len) < 0)
 		return NULL;
-	for (i = 0; pointer[i]; i++)
-		if (pointer[i] == '\\')
-			pointer[i] = '/';
+	convert_slashes(pointer);
 	return pointer;
 }
 
@@ -752,7 +931,7 @@ static const char *quote_arg(const char *arg)
 		return arg;
 
 	/* insert \ where necessary */
-	d = q = xmalloc(len+n+3);
+	d = q = xmalloc(st_add3(len, n, 3));
 	*d++ = '"';
 	while (*arg) {
 		if (*arg == '"')
@@ -812,64 +991,14 @@ static const char *parse_interpreter(const char *cmd)
 }
 
 /*
- * Splits the PATH into parts.
- */
-static char **get_path_split(void)
-{
-	char *p, **path, *envpath = mingw_getenv("PATH");
-	int i, n = 0;
-
-	if (!envpath || !*envpath)
-		return NULL;
-
-	envpath = xstrdup(envpath);
-	p = envpath;
-	while (p) {
-		char *dir = p;
-		p = strchr(p, ';');
-		if (p) *p++ = '\0';
-		if (*dir) {	/* not earlier, catches series of ; */
-			++n;
-		}
-	}
-	if (!n)
-		return NULL;
-
-	path = xmalloc((n+1)*sizeof(char *));
-	p = envpath;
-	i = 0;
-	do {
-		if (*p)
-			path[i++] = xstrdup(p);
-		p = p+strlen(p)+1;
-	} while (i < n);
-	path[i] = NULL;
-
-	free(envpath);
-
-	return path;
-}
-
-static void free_path_split(char **path)
-{
-	char **p = path;
-
-	if (!path)
-		return;
-
-	while (*p)
-		free(*p++);
-	free(path);
-}
-
-/*
  * exe_only means that we only want to detect .exe files, but not scripts
  * (which do not have an extension)
  */
-static char *lookup_prog(const char *dir, const char *cmd, int isexe, int exe_only)
+static char *lookup_prog(const char *dir, int dirlen, const char *cmd,
+			 int isexe, int exe_only)
 {
 	char path[MAX_PATH];
-	snprintf(path, sizeof(path), "%s/%s.exe", dir, cmd);
+	snprintf(path, sizeof(path), "%.*s\\%s.exe", dirlen, dir, cmd);
 
 	if (!isexe && access(path, F_OK) == 0)
 		return xstrdup(path);
@@ -884,17 +1013,29 @@ static char *lookup_prog(const char *dir, const char *cmd, int isexe, int exe_on
  * Determines the absolute path of cmd using the split path in path.
  * If cmd contains a slash or backslash, no lookup is performed.
  */
-static char *path_lookup(const char *cmd, char **path, int exe_only)
+static char *path_lookup(const char *cmd, int exe_only)
 {
+	const char *path;
 	char *prog = NULL;
 	int len = strlen(cmd);
 	int isexe = len >= 4 && !strcasecmp(cmd+len-4, ".exe");
 
 	if (strchr(cmd, '/') || strchr(cmd, '\\'))
-		prog = xstrdup(cmd);
+		return xstrdup(cmd);
 
-	while (!prog && *path)
-		prog = lookup_prog(*path++, cmd, isexe, exe_only);
+	path = mingw_getenv("PATH");
+	if (!path)
+		return NULL;
+
+	while (!prog) {
+		const char *sep = strchrnul(path, ';');
+		int dirlen = sep - path;
+		if (dirlen)
+			prog = lookup_prog(path, dirlen, cmd, isexe, exe_only);
+		if (!*sep)
+			break;
+		path = sep + 1;
+	}
 
 	return prog;
 }
@@ -920,7 +1061,7 @@ static wchar_t *make_environment_block(char **deltaenv)
 		i++;
 
 	/* copy the environment, leaving space for changes */
-	tmpenv = xmalloc((size + i) * sizeof(char*));
+	ALLOC_ARRAY(tmpenv, size + i);
 	memcpy(tmpenv, environ, size * sizeof(char*));
 
 	/* merge supplied environment changes into the temporary environment */
@@ -1011,7 +1152,7 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 			free(quoted);
 	}
 
-	wargs = xmalloc((2 * args.len + 1) * sizeof(wchar_t));
+	ALLOC_ARRAY(wargs, st_add(st_mult(2, args.len), 1));
 	xutftowcs(wargs, args.buf, 2 * args.len + 1);
 	strbuf_release(&args);
 
@@ -1061,8 +1202,7 @@ pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **deltaenv,
 		     int fhin, int fhout, int fherr)
 {
 	pid_t pid;
-	char **path = get_path_split();
-	char *prog = path_lookup(cmd, path, 0);
+	char *prog = path_lookup(cmd, 0);
 
 	if (!prog) {
 		errno = ENOENT;
@@ -1073,7 +1213,7 @@ pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **deltaenv,
 
 		if (interpr) {
 			const char *argv0 = argv[0];
-			char *iprog = path_lookup(interpr, path, 1);
+			char *iprog = path_lookup(interpr, 1);
 			argv[0] = prog;
 			if (!iprog) {
 				errno = ENOENT;
@@ -1091,26 +1231,23 @@ pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **deltaenv,
 					       fhin, fhout, fherr);
 		free(prog);
 	}
-	free_path_split(path);
 	return pid;
 }
 
 static int try_shell_exec(const char *cmd, char *const *argv)
 {
 	const char *interpr = parse_interpreter(cmd);
-	char **path;
 	char *prog;
 	int pid = 0;
 
 	if (!interpr)
 		return 0;
-	path = get_path_split();
-	prog = path_lookup(interpr, path, 1);
+	prog = path_lookup(interpr, 1);
 	if (prog) {
 		int argc = 0;
 		const char **argv2;
 		while (argv[argc]) argc++;
-		argv2 = xmalloc(sizeof(*argv) * (argc+1));
+		ALLOC_ARRAY(argv2, argc + 1);
 		argv2[0] = (char *)cmd;	/* full path to the script file */
 		memcpy(&argv2[1], &argv[1], sizeof(*argv) * argc);
 		pid = mingw_spawnv(prog, argv2, 1);
@@ -1124,7 +1261,6 @@ static int try_shell_exec(const char *cmd, char *const *argv)
 		free(prog);
 		free(argv2);
 	}
-	free_path_split(path);
 	return pid;
 }
 
@@ -1146,8 +1282,7 @@ int mingw_execv(const char *cmd, char *const *argv)
 
 int mingw_execvp(const char *cmd, char *const *argv)
 {
-	char **path = get_path_split();
-	char *prog = path_lookup(cmd, path, 0);
+	char *prog = path_lookup(cmd, 0);
 
 	if (prog) {
 		mingw_execv(prog, argv);
@@ -1155,7 +1290,6 @@ int mingw_execvp(const char *cmd, char *const *argv)
 	} else
 		errno = ENOENT;
 
-	free_path_split(path);
 	return -1;
 }
 
@@ -1584,7 +1718,12 @@ repeat:
 	if (gle == ERROR_ACCESS_DENIED &&
 	    (attrs = GetFileAttributesW(wpnew)) != INVALID_FILE_ATTRIBUTES) {
 		if (attrs & FILE_ATTRIBUTE_DIRECTORY) {
-			errno = EISDIR;
+			DWORD attrsold = GetFileAttributesW(wpold);
+			if (attrsold == INVALID_FILE_ATTRIBUTES ||
+			    !(attrsold & FILE_ATTRIBUTE_DIRECTORY))
+				errno = EISDIR;
+			else if (!_wrmdir(wpnew))
+				goto repeat;
 			return -1;
 		}
 		if ((attrs & FILE_ATTRIBUTE_READONLY) &&
@@ -1796,47 +1935,6 @@ int mingw_raise(int sig)
 	}
 }
 
-
-static const char *make_backslash_path(const char *path)
-{
-	static char buf[PATH_MAX + 1];
-	char *c;
-
-	if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
-		die("Too long path: %.*s", 60, path);
-
-	for (c = buf; *c; c++) {
-		if (*c == '/')
-			*c = '\\';
-	}
-	return buf;
-}
-
-void mingw_open_html(const char *unixpath)
-{
-	const char *htmlpath = make_backslash_path(unixpath);
-	typedef HINSTANCE (WINAPI *T)(HWND, const char *,
-			const char *, const char *, const char *, INT);
-	T ShellExecute;
-	HMODULE shell32;
-	int r;
-
-	shell32 = LoadLibrary("shell32.dll");
-	if (!shell32)
-		die("cannot load shell32.dll");
-	ShellExecute = (T)GetProcAddress(shell32, "ShellExecuteA");
-	if (!ShellExecute)
-		die("cannot run browser");
-
-	printf("Launching default browser to display HTML ...\n");
-	r = (int)ShellExecute(NULL, "open", htmlpath, NULL, "\\", SW_SHOWNORMAL);
-	FreeLibrary(shell32);
-	/* see the MSDN documentation referring to the result codes here */
-	if (r <= 32) {
-		die("failed to launch browser for %.*s", MAX_PATH, unixpath);
-	}
-}
-
 int link(const char *oldpath, const char *newpath)
 {
 	typedef BOOL (WINAPI *T)(LPCWSTR, LPCWSTR, LPSECURITY_ATTRIBUTES);
@@ -1915,28 +2013,31 @@ pid_t waitpid(pid_t pid, int *status, int options)
 	return -1;
 }
 
+int mingw_skip_dos_drive_prefix(char **path)
+{
+	int ret = has_dos_drive_prefix(*path);
+	*path += ret;
+	return ret;
+}
+
 int mingw_offset_1st_component(const char *path)
 {
-	int offset = 0;
-	if (has_dos_drive_prefix(path))
-		offset = 2;
+	char *pos = (char *)path;
 
 	/* unc paths */
-	else if (is_dir_sep(path[0]) && is_dir_sep(path[1])) {
-
+	if (!skip_dos_drive_prefix(&pos) &&
+			is_dir_sep(pos[0]) && is_dir_sep(pos[1])) {
 		/* skip server name */
-		char *pos = strpbrk(path + 2, "\\/");
+		pos = strpbrk(pos + 2, "\\/");
 		if (!pos)
 			return 0; /* Error: malformed unc path */
 
 		do {
 			pos++;
 		} while (*pos && !is_dir_sep(*pos));
-
-		offset = pos - path;
 	}
 
-	return offset + is_dir_sep(path[offset]);
+	return pos + is_dir_sep(*pos) - path;
 }
 
 int xutftowcsn(wchar_t *wcs, const char *utfs, size_t wcslen, int utflen)
@@ -2024,6 +2125,35 @@ int xwcstoutf(char *utf, const wchar_t *wcs, size_t utflen)
 	return -1;
 }
 
+static void setup_windows_environment(void)
+{
+	char *tmp = getenv("TMPDIR");
+
+	/* on Windows it is TMP and TEMP */
+	if (!tmp) {
+		if (!(tmp = getenv("TMP")))
+			tmp = getenv("TEMP");
+		if (tmp) {
+			setenv("TMPDIR", tmp, 1);
+			tmp = getenv("TMPDIR");
+		}
+	}
+
+	if (tmp) {
+		/*
+		 * Convert all dir separators to forward slashes,
+		 * to help shell commands called from the Git
+		 * executable (by not mistaking the dir separators
+		 * for escape characters).
+		 */
+		convert_slashes(tmp);
+	}
+
+	/* simulate TERM to enable auto-color (see color.c) */
+	if (!getenv("TERM"))
+		setenv("TERM", "cygwin", 1);
+}
+
 /*
  * Disable MSVCRT command line wildcard expansion (__getmainargs called from
  * mingw startup code, see init.c in mingw runtime).
@@ -2037,7 +2167,7 @@ typedef struct {
 extern int __wgetmainargs(int *argc, wchar_t ***argv, wchar_t ***env, int glob,
 		_startupinfo *si);
 
-static NORETURN void die_startup()
+static NORETURN void die_startup(void)
 {
 	fputs("fatal: not enough memory for initialization", stderr);
 	exit(128);
@@ -2057,20 +2187,78 @@ static char *wcstoutfdup_startup(char *buffer, const wchar_t *wcs, size_t len)
 	return memcpy(malloc_startup(len), buffer, len);
 }
 
-void mingw_startup()
+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;
 	char *buffer;
 	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)
 		die_startup();
 
 	/* determine size of argv and environ conversion buffer */
-	maxlen = wcslen(_wpgmptr);
+	maxlen = wcslen(wargv[0]);
 	for (i = 1; i < argc; i++)
 		maxlen = max(maxlen, wcslen(wargv[i]));
 	for (i = 0; wenv[i]; i++)
@@ -2090,8 +2278,7 @@ void mingw_startup()
 	buffer = malloc_startup(maxlen);
 
 	/* convert command line arguments and environment to UTF-8 */
-	__argv[0] = wcstoutfdup_startup(buffer, _wpgmptr, maxlen);
-	for (i = 1; i < argc; i++)
+	for (i = 0; i < argc; i++)
 		__argv[i] = wcstoutfdup_startup(buffer, wargv[i], maxlen);
 	for (i = 0; wenv[i]; i++)
 		environ[i] = wcstoutfdup_startup(buffer, wenv[i], maxlen);
@@ -2102,19 +2289,7 @@ void mingw_startup()
 	qsort(environ, i, sizeof(char*), compareenv);
 
 	/* fix Windows specific environment settings */
-
-	/* on Windows it is TMP and TEMP */
-	if (!mingw_getenv("TMPDIR")) {
-		const char *tmp = mingw_getenv("TMP");
-		if (!tmp)
-			tmp = mingw_getenv("TEMP");
-		if (tmp)
-			setenv("TMPDIR", tmp, 1);
-	}
-
-	/* simulate TERM to enable auto-color (see color.c) */
-	if (!getenv("TERM"))
-		setenv("TERM", "cygwin", 1);
+	setup_windows_environment();
 
 	/* initialize critical section for waitpid pinfo_t list */
 	InitializeCriticalSection(&pinfo_cs);
@@ -2128,3 +2303,16 @@ void mingw_startup()
 	/* initialize Unicode console */
 	winansi_init();
 }
+
+int uname(struct utsname *buf)
+{
+	unsigned v = (unsigned)GetVersion();
+	memset(buf, 0, sizeof(*buf));
+	xsnprintf(buf->sysname, sizeof(buf->sysname), "Windows");
+	xsnprintf(buf->release, sizeof(buf->release),
+		 "%u.%u", v & 0xff, (v >> 8) & 0xff);
+	/* assuming NT variants only.. */
+	xsnprintf(buf->version, sizeof(buf->version),
+		  "%u", (v >> 16) & 0x7fff);
+	return 0;
+}