windows

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Author : Phillip Trudeau
Date : 2021-06-11 09:22:41
Hash : bc7ac134
Message : Windows: Fix SDL_GetBasePath() truncating paths SDL_GetBasePath grows its path buffer for long paths, but GetModuleFileNameExW always truncates and succeeds, so `len` was always equal to (buflen - 1) which is 127. This is easily fixed by checking for (buflen - 1) instead of buflen. For paths longer than MAX_PATH, this problem sometimes got hidden by Windows path shortening ("C:\PROGRA~1\" etc.). Tested on Windows 10 x64 19041 and 10586.

SDL_sysfilesystem.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"

#ifdef SDL_FILESYSTEM_WINDOWS

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* System dependent filesystem routines                                */

#include "../../core/windows/SDL_windows.h"
#include <shlobj.h>

#include "SDL_error.h"
#include "SDL_stdinc.h"
#include "SDL_filesystem.h"

char *
SDL_GetBasePath(void)
{
    typedef DWORD (WINAPI *GetModuleFileNameExW_t)(HANDLE, HMODULE, LPWSTR, DWORD);
    GetModuleFileNameExW_t pGetModuleFileNameExW;
    DWORD buflen = 128;
    WCHAR *path = NULL;
    HANDLE psapi = LoadLibrary(TEXT("psapi.dll"));
    char *retval = NULL;
    DWORD len = 0;
    int i;

    if (!psapi) {
        WIN_SetError("Couldn't load psapi.dll");
        return NULL;
    }

    pGetModuleFileNameExW = (GetModuleFileNameExW_t)GetProcAddress(psapi, "GetModuleFileNameExW");
    if (!pGetModuleFileNameExW) {
        WIN_SetError("Couldn't find GetModuleFileNameExW");
        FreeLibrary(psapi);
        return NULL;
    }

    while (SDL_TRUE) {
        void *ptr = SDL_realloc(path, buflen * sizeof (WCHAR));
        if (!ptr) {
            SDL_free(path);
            FreeLibrary(psapi);
            SDL_OutOfMemory();
            return NULL;
        }

        path = (WCHAR *) ptr;

        len = pGetModuleFileNameExW(GetCurrentProcess(), NULL, path, buflen);
        /* if it truncated, then len >= buflen - 1 */
        /* if there was enough room (or failure), len < buflen - 1 */
        if (len < buflen - 1) {
            break;
        }

        /* buffer too small? Try again. */
        buflen *= 2;
    }

    FreeLibrary(psapi);

    if (len == 0) {
        SDL_free(path);
        WIN_SetError("Couldn't locate our .exe");
        return NULL;
    }

    for (i = len-1; i > 0; i--) {
        if (path[i] == '\\') {
            break;
        }
    }

    SDL_assert(i > 0); /* Should have been an absolute path. */
    path[i+1] = '\0';  /* chop off filename. */

    retval = WIN_StringToUTF8W(path);
    SDL_free(path);

    return retval;
}

char *
SDL_GetPrefPath(const char *org, const char *app)
{
    /*
     * Vista and later has a new API for this, but SHGetFolderPath works there,
     *  and apparently just wraps the new API. This is the new way to do it:
     *
     *     SHGetKnownFolderPath(FOLDERID_RoamingAppData, KF_FLAG_CREATE,
     *                          NULL, &wszPath);
     */

    WCHAR path[MAX_PATH];
    char *retval = NULL;
    WCHAR* worg = NULL;
    WCHAR* wapp = NULL;
    size_t new_wpath_len = 0;
    BOOL api_result = FALSE;

    if (!app) {
        SDL_InvalidParamError("app");
        return NULL;
    }
    if (!org) {
        org = "";
    }

    if (!SUCCEEDED(SHGetFolderPathW(NULL, CSIDL_APPDATA | CSIDL_FLAG_CREATE, NULL, 0, path))) {
        WIN_SetError("Couldn't locate our prefpath");
        return NULL;
    }

    worg = WIN_UTF8ToStringW(org);
    if (worg == NULL) {
        SDL_OutOfMemory();
        return NULL;
    }

    wapp = WIN_UTF8ToStringW(app);
    if (wapp == NULL) {
        SDL_free(worg);
        SDL_OutOfMemory();
        return NULL;
    }

    new_wpath_len = SDL_wcslen(worg) + SDL_wcslen(wapp) + SDL_wcslen(path) + 3;

    if ((new_wpath_len + 1) > MAX_PATH) {
        SDL_free(worg);
        SDL_free(wapp);
        WIN_SetError("Path too long.");
        return NULL;
    }

    if (*worg) {
        SDL_wcslcat(path, L"\\", SDL_arraysize(path));
        SDL_wcslcat(path, worg, SDL_arraysize(path));
    }
    SDL_free(worg);

    api_result = CreateDirectoryW(path, NULL);
    if (api_result == FALSE) {
        if (GetLastError() != ERROR_ALREADY_EXISTS) {
            SDL_free(wapp);
            WIN_SetError("Couldn't create a prefpath.");
            return NULL;
        }
    }

    SDL_wcslcat(path, L"\\", SDL_arraysize(path));
    SDL_wcslcat(path, wapp, SDL_arraysize(path));
    SDL_free(wapp);

    api_result = CreateDirectoryW(path, NULL);
    if (api_result == FALSE) {
        if (GetLastError() != ERROR_ALREADY_EXISTS) {
            WIN_SetError("Couldn't create a prefpath.");
            return NULL;
        }
    }

    SDL_wcslcat(path, L"\\", SDL_arraysize(path));

    retval = WIN_StringToUTF8W(path);

    return retval;
}

#endif /* SDL_FILESYSTEM_WINDOWS */

/* vi: set ts=4 sw=4 expandtab: */

kc3-lang/SDL/src/filesystem/windows

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kc3-lang/SDL /src/filesystem/windows