[PATCH 0/1] mingw: handle non-ASCII PATH components correctly

[PATCH 0/1] mingw: handle non-ASCII PATH components correctly

[Johannes Schindelin via GitGitGadget]

We need to be careful on Windows: there are "ANSI" versions of the API
functions that take char *, and "Unicode" versions that take "wchar_t `
strings as parameters. The ANSI versions are subject to the current
codepage, i.e. almost guaranteed to *not handle UTF-8. Internally, we do
want to use UTF-8, though, at least in compat/mingw.c, so we really have to
use the Unicode versions of the Win32 API.

Adam Roben (1):
  mingw: fix launching of externals from Unicode paths

 compat/mingw.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)


base-commit: 8104ec994ea3849a968b4667d072fedd1e688642
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-135%2Fdscho%2Ffix-externals-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-135/dscho/fix-externals-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/135
-- 
gitgitgadget

[PATCH 1/1] mingw: fix launching of externals from Unicode paths

[Adam Roben via GitGitGadget]

From: Adam Roben <adam@roben.org>

If Git were installed in a path containing non-ASCII characters,
commands such as `git am` and `git submodule`, which are implemented as
externals, would fail to launch with the following error:

> fatal: 'am' appears to be a git command, but we were not
> able to execute it. Maybe git-am is broken?

This was due to lookup_prog not being Unicode-aware. It was somehow
missed in 85faec9d3a (Win32: Unicode file name support (except dirent),
2012-03-15).

Note that the only problem in this function was calling
`GetFileAttributes()` instead of `GetFileAttributesW()`. The calls to
`access()` were fine because `access()` is a macro which resolves to
`mingw_access()`, which already handles Unicode correctly. But
`lookup_prog()` was changed to use `_waccess()` directly so that we only
convert the path to UTF-16 once.

To make things work correctly, we have to maintain UTF-8 and UTF-16
versions in tandem in `lookup_prog()`.

Signed-off-by: Adam Roben <adam@roben.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 8141f77189..9f02403ebf 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1161,14 +1161,21 @@ static char *lookup_prog(const char *dir, int dirlen, const char *cmd,
 			 int isexe, int exe_only)
 {
 	char path[MAX_PATH];
+	wchar_t wpath[MAX_PATH];
 	snprintf(path, sizeof(path), "%.*s\\%s.exe", dirlen, dir, cmd);
 
-	if (!isexe && access(path, F_OK) == 0)
+	if (xutftowcs_path(wpath, path) < 0)
+		return NULL;
+
+	if (!isexe && _waccess(wpath, F_OK) == 0)
 		return xstrdup(path);
-	path[strlen(path)-4] = '\0';
-	if ((!exe_only || isexe) && access(path, F_OK) == 0)
-		if (!(GetFileAttributes(path) & FILE_ATTRIBUTE_DIRECTORY))
+	wpath[wcslen(wpath)-4] = '\0';
+	if ((!exe_only || isexe) && _waccess(wpath, F_OK) == 0) {
+		if (!(GetFileAttributesW(wpath) & FILE_ATTRIBUTE_DIRECTORY)) {
+			path[strlen(path)-4] = '\0';
 			return xstrdup(path);
+		}
+	}
 	return NULL;
 }
 
-- 
gitgitgadget

Re: [PATCH 1/1] mingw: fix launching of externals from Unicode paths

[Junio C Hamano]

"Adam Roben via GitGitGadget" <gitgitgadget@gmail.com> writes:

> Note that the only problem in this function was calling
> `GetFileAttributes()` instead of `GetFileAttributesW()`. The calls to
> `access()` were fine because `access()` is a macro which resolves to
> `mingw_access()`, which already handles Unicode correctly. But
> `lookup_prog()` was changed to use `_waccess()` directly so that we only
> convert the path to UTF-16 once.

Nicely explained.  Thanks.

>
> To make things work correctly, we have to maintain UTF-8 and UTF-16
> versions in tandem in `lookup_prog()`.
>
> Signed-off-by: Adam Roben <adam@roben.org>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>  compat/mingw.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/compat/mingw.c b/compat/mingw.c
> index 8141f77189..9f02403ebf 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -1161,14 +1161,21 @@ static char *lookup_prog(const char *dir, int dirlen, const char *cmd,
>  			 int isexe, int exe_only)
>  {
>  	char path[MAX_PATH];
> +	wchar_t wpath[MAX_PATH];
>  	snprintf(path, sizeof(path), "%.*s\\%s.exe", dirlen, dir, cmd);
>  
> -	if (!isexe && access(path, F_OK) == 0)
> +	if (xutftowcs_path(wpath, path) < 0)
> +		return NULL;
> +
> +	if (!isexe && _waccess(wpath, F_OK) == 0)
>  		return xstrdup(path);
> -	path[strlen(path)-4] = '\0';
> -	if ((!exe_only || isexe) && access(path, F_OK) == 0)
> -		if (!(GetFileAttributes(path) & FILE_ATTRIBUTE_DIRECTORY))
> +	wpath[wcslen(wpath)-4] = '\0';
> +	if ((!exe_only || isexe) && _waccess(wpath, F_OK) == 0) {
> +		if (!(GetFileAttributesW(wpath) & FILE_ATTRIBUTE_DIRECTORY)) {
> +			path[strlen(path)-4] = '\0';
>  			return xstrdup(path);
> +		}
> +	}
>  	return NULL;
>  }