/*

 * Copyright 2016-2025 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#if defined(__linux) || defined(__sun) || defined(__hpux)

/*

 * Following definition aliases fopen to fopen64 on above mentioned

 * platforms. This makes it possible to open and sequentially access files

 * larger than 2GB from 32-bit application. It does not allow one to traverse

 * them beyond 2GB with fseek/ftell, but on the other hand *no* 32-bit

 * platform permits that, not with fseek/ftell. Not to mention that breaking

 * 2GB limit for seeking would require surgery to *our* API. But sequential

 * access suffices for practical cases when you can run into large files,

 * such as fingerprinting, so we can let API alone. For reference, the list

 * of 32-bit platforms which allow for sequential access of large files

 * without extra "magic" comprise *BSD, Darwin, IRIX...

 */

#ifndef _FILE_OFFSET_BITS

#define _FILE_OFFSET_BITS 64

#endif

#endif

#include "internal/e_os.h"

#include "internal/cryptlib.h"

#if !defined(OPENSSL_NO_STDIO)

#include <stdio.h>

#ifdef __DJGPP__

#include <unistd.h>

#endif

FILE *openssl_fopen(const char *filename, const char *mode)

{

    FILE *file = NULL;

#if defined(_WIN32) && defined(CP_UTF8)

    int sz, len_0;

    DWORD flags;

#endif

    if (filename == NULL)

        return NULL;

#if defined(_WIN32) && defined(CP_UTF8)

    len_0 = (int)strlen(filename) + 1;

    /*

     * Basically there are three cases to cover: a) filename is

     * pure ASCII string; b) actual UTF-8 encoded string and

     * c) locale-ized string, i.e. one containing 8-bit

     * characters that are meaningful in current system locale.

     * If filename is pure ASCII or real UTF-8 encoded string,

     * MultiByteToWideChar succeeds and _wfopen works. If

     * filename is locale-ized string, chances are that

     * MultiByteToWideChar fails reporting

     * ERROR_NO_UNICODE_TRANSLATION, in which case we fall

     * back to fopen...

     */

    if ((sz = MultiByteToWideChar(CP_UTF8, (flags = MB_ERR_INVALID_CHARS),

             filename, len_0, NULL, 0))

            > 0

        || (GetLastError() == ERROR_INVALID_FLAGS && (sz = MultiByteToWideChar(CP_UTF8, (flags = 0), filename, len_0, NULL, 0)) > 0)) {

        WCHAR wmode[8];

        WCHAR *wfilename = _alloca(sz * sizeof(WCHAR));

        if (MultiByteToWideChar(CP_UTF8, flags,

                filename, len_0, wfilename, sz)

            && MultiByteToWideChar(CP_UTF8, 0, mode, (int)(strlen(mode) + 1),

                wmode, OSSL_NELEM(wmode))

            && (file = _wfopen(wfilename, wmode)) == NULL && (errno == ENOENT || errno == EBADF)) {

            /*

             * UTF-8 decode succeeded, but no file, filename

             * could still have been locale-ized...

             */

            file = fopen(filename, mode);

        }

    } else if (GetLastError() == ERROR_NO_UNICODE_TRANSLATION) {

        file = fopen(filename, mode);

    }

#elif defined(__DJGPP__)

    {

        char *newname = NULL;

        if (pathconf(filename, _PC_NAME_MAX) <= 12) { /* 8.3 file system? */

            char *iterator;

            char lastchar;

            if ((newname = OPENSSL_malloc(strlen(filename) + 1)) == NULL)

                return NULL;

            for (iterator = newname, lastchar = '\0';

                *filename; filename++, iterator++) {

                if (lastchar == '/' && filename[0] == '.'

                    && filename[1] != '.' && filename[1] != '/') {

                    /* Leading dots are not permitted in plain DOS. */

                    *iterator = '_';

                } else {

                    *iterator = *filename;

                }

                lastchar = *filename;

            }

            *iterator = '\0';

            filename = newname;

        }

        file = fopen(filename, mode);

        OPENSSL_free(newname);

    }

#else

    file = fopen(filename, mode);

#endif

    return file;

}

#else

void *openssl_fopen(const char *filename, const char *mode)

{

    return NULL;

}

#endif