[PATCH v2 06/20] mingw: replace mingw_startup() hack
- From
Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
- Date
- Jun 19, 2019, 21:05 UTC
- Message-ID
- <02f618464f85c0d61921f22948369f76b630e1e0.1560978354.git.gitgitgadget@gmail.com>
- In-Reply-To
- <pull.149.v2.git.gitgitgadget@gmail.com>
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Git for Windows has special code to retrieve the command-line parameters (and even the environment) in UTF-16 encoding, so that they can be converted to UTF-8. This is necessary because Git for Windows wants to use UTF-8 encoded strings throughout its code, and the main() function does not get the parameters in that encoding.
To do that, we used the __wgetmainargs() function, which is not even a Win32 API function, but provided by the MINGW "runtime" instead.
Obviously, this method would not work with any compiler other than GCC, and in preparation for compiling with Visual C++, we would like to avoid precisely that.
Lucky us, there is a much more elegant way: we can simply implement the UTF-16 variant of `main()`: `wmain()`.
To make that work, we need to link with -municode. The command-line parameters are passed to `wmain()` encoded in UTF-16, as desired, and this method also works with GCC, and also with Visual C++ after adjusting the MSVC linker flags to force it to use `wmain()`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> --- compat/mingw.c | 53 +++++++++++++++++++++++++++++++----------------- compat/mingw.h | 22 ++++++++++---------- config.mak.uname | 3 ++- 3 files changed, 47 insertions(+), 31 deletions(-)
diff --git a/compat/mingw.c b/compat/mingw.c index 9b6d2400e1..0d8713e515 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -2301,18 +2301,13 @@ static void setup_windows_environment(void) setenv("TERM", "cygwin", 1); } +#if !defined(_MSC_VER) /* * Disable MSVCRT command line wildcard expansion (__getmainargs called from * mingw startup code, see init.c in mingw runtime). */ int _CRT_glob = 0; - -typedef struct { - int newmode; -} _startupinfo; - -extern int __wgetmainargs(int *argc, wchar_t ***argv, wchar_t ***env, int glob, - _startupinfo *si); +#endif static NORETURN void die_startup(void) { @@ -2390,22 +2385,25 @@ static void maybe_redirect_std_handles(void) GENERIC_WRITE, FILE_FLAG_NO_BUFFERING); } -void mingw_startup(void) +/* + * We implement wmain() and compile with -municode, which would + * normally ignore main(), but we call the latter from the former + * so that we can handle non-ASCII command-line parameters + * appropriately. + * + * To be more compatible with the core git code, we convert + * argv into UTF8 and pass them directly to main(). + */ +int wmain(int argc, const wchar_t **wargv) { - int i, maxlen, argc; - char *buffer; - wchar_t **wenv, **wargv; - _startupinfo si; + int i, maxlen, exit_status; + char *buffer, **save; + const char **argv; trace2_initialize_clock(); 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(wargv[0]); for (i = 1; i < argc; i++) @@ -2415,9 +2413,16 @@ void mingw_startup(void) maxlen = 3 * maxlen + 1; buffer = malloc_startup(maxlen); - /* convert command line arguments and environment to UTF-8 */ + /* + * Create a UTF-8 version of w_argv. Also create a "save" copy + * to remember all the string pointers because parse_options() + * will remove claimed items from the argv that we pass down. + */ + ALLOC_ARRAY(argv, argc + 1); + ALLOC_ARRAY(save, argc + 1); for (i = 0; i < argc; i++) - __argv[i] = wcstoutfdup_startup(buffer, wargv[i], maxlen); + argv[i] = save[i] = wcstoutfdup_startup(buffer, wargv[i], maxlen); + argv[i] = save[i] = NULL; free(buffer); /* fix Windows specific environment settings */ @@ -2436,6 +2441,16 @@ void mingw_startup(void) /* initialize Unicode console */ winansi_init(); + + /* invoke the real main() using our utf8 version of argv. */ + exit_status = main(argc, argv); + + for (i = 0; i < argc; i++) + free(save[i]); + free(save); + free(argv); + + return exit_status; } int uname(struct utsname *buf) diff --git a/compat/mingw.h b/compat/mingw.h index 593bdbffe6..210f1b01a8 100644 --- a/compat/mingw.h +++ b/compat/mingw.h @@ -562,18 +562,18 @@ int xwcstoutf(char *utf, const wchar_t *wcs, size_t utflen); extern CRITICAL_SECTION pinfo_cs; /* - * A replacement of main() that adds win32 specific initialization. + * Git, like most portable C applications, implements a main() function. On + * Windows, this main() function would receive parameters encoded in the + * current locale, but Git for Windows would prefer UTF-8 encoded parameters. + * + * To make that happen, we still declare main() here, and then declare and + * implement wmain() (which is the Unicode variant of main()) and compile with + * -municode. This wmain() function reencodes the parameters from UTF-16 to + * UTF-8 format, sets up a couple of other things as required on Windows, and + * then hands off to the main() function. */ - -void mingw_startup(void); -#define main(c,v) dummy_decl_mingw_main(void); \ -static int mingw_main(c,v); \ -int main(int argc, const char **argv) \ -{ \ - mingw_startup(); \ - return mingw_main(__argc, (void *)__argv); \ -} \ -static int mingw_main(c,v) +int wmain(int argc, const wchar_t **w_argv); +int main(int argc, const char **argv); /* * Used by Pthread API implementation for Windows diff --git a/config.mak.uname b/config.mak.uname index 9fc053cac0..6ddece0350 100644 --- a/config.mak.uname +++ b/config.mak.uname @@ -401,7 +401,7 @@ ifeq ($(uname_S),Windows) compat/win32/trace2_win32_process_info.o \ compat/win32/dirent.o COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DNOGDI -DHAVE_STRING_H -Icompat -Icompat/regex -Icompat/win32 -DSTRIP_EXTENSION=\".exe\" - BASIC_LDFLAGS = -IGNORE:4217 -IGNORE:4049 -NOLOGO -SUBSYSTEM:CONSOLE + BASIC_LDFLAGS = -IGNORE:4217 -IGNORE:4049 -NOLOGO -ENTRY:wmainCRTStartup -SUBSYSTEM:CONSOLE EXTLIBS = user32.lib advapi32.lib shell32.lib wininet.lib ws2_32.lib invalidcontinue.obj PTHREAD_LIBS = lib = @@ -548,6 +548,7 @@ ifneq (,$(findstring MINGW,$(uname_S))) ETAGS_TARGET = ETAGS NO_POSIX_GOODIES = UnfortunatelyYes DEFAULT_HELP_FORMAT = html + BASIC_LDFLAGS += -municode COMPAT_CFLAGS += -DNOGDI -Icompat -Icompat/win32 COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\" COMPAT_OBJS += compat/mingw.o compat/winansi.o \
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