1/*
2 * Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License").  You may not use
5 * this file except in compliance with the License.  You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10# if defined(__linux) || defined(__sun) || defined(__hpux)
11/*
12 * Following definition aliases fopen to fopen64 on above mentioned
13 * platforms. This makes it possible to open and sequentially access files
14 * larger than 2GB from 32-bit application. It does not allow to traverse
15 * them beyond 2GB with fseek/ftell, but on the other hand *no* 32-bit
16 * platform permits that, not with fseek/ftell. Not to mention that breaking
17 * 2GB limit for seeking would require surgery to *our* API. But sequential
18 * access suffices for practical cases when you can run into large files,
19 * such as fingerprinting, so we can let API alone. For reference, the list
20 * of 32-bit platforms which allow for sequential access of large files
21 * without extra "magic" comprise *BSD, Darwin, IRIX...
22 */
23#  ifndef _FILE_OFFSET_BITS
24#   define _FILE_OFFSET_BITS 64
25#  endif
26# endif
27
28#include "e_os.h"
29#include "internal/cryptlib.h"
30
31#if !defined(OPENSSL_NO_STDIO)
32
33# include <stdio.h>
34# ifdef __DJGPP__
35#  include <unistd.h>
36# endif
37
38FILE *openssl_fopen(const char *filename, const char *mode)
39{
40    FILE *file = NULL;
41# if defined(_WIN32) && defined(CP_UTF8)
42    int sz, len_0 = (int)strlen(filename) + 1;
43    DWORD flags;
44
45    /*
46     * Basically there are three cases to cover: a) filename is
47     * pure ASCII string; b) actual UTF-8 encoded string and
48     * c) locale-ized string, i.e. one containing 8-bit
49     * characters that are meaningful in current system locale.
50     * If filename is pure ASCII or real UTF-8 encoded string,
51     * MultiByteToWideChar succeeds and _wfopen works. If
52     * filename is locale-ized string, chances are that
53     * MultiByteToWideChar fails reporting
54     * ERROR_NO_UNICODE_TRANSLATION, in which case we fall
55     * back to fopen...
56     */
57    if ((sz = MultiByteToWideChar(CP_UTF8, (flags = MB_ERR_INVALID_CHARS),
58                                  filename, len_0, NULL, 0)) > 0 ||
59        (GetLastError() == ERROR_INVALID_FLAGS &&
60         (sz = MultiByteToWideChar(CP_UTF8, (flags = 0),
61                                   filename, len_0, NULL, 0)) > 0)
62        ) {
63        WCHAR wmode[8];
64        WCHAR *wfilename = _alloca(sz * sizeof(WCHAR));
65
66        if (MultiByteToWideChar(CP_UTF8, flags,
67                                filename, len_0, wfilename, sz) &&
68            MultiByteToWideChar(CP_UTF8, 0, mode, strlen(mode) + 1,
69                                wmode, OSSL_NELEM(wmode)) &&
70            (file = _wfopen(wfilename, wmode)) == NULL &&
71            (errno == ENOENT || errno == EBADF)
72            ) {
73            /*
74             * UTF-8 decode succeeded, but no file, filename
75             * could still have been locale-ized...
76             */
77            file = fopen(filename, mode);
78        }
79    } else if (GetLastError() == ERROR_NO_UNICODE_TRANSLATION) {
80        file = fopen(filename, mode);
81    }
82# elif defined(__DJGPP__)
83    {
84        char *newname = NULL;
85
86        if (pathconf(filename, _PC_NAME_MAX) <= 12) {  /* 8.3 file system? */
87            char *iterator;
88            char lastchar;
89
90            if ((newname = OPENSSL_malloc(strlen(filename) + 1)) == NULL) {
91                ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
92                return NULL;
93            }
94
95            for (iterator = newname, lastchar = '\0';
96                *filename; filename++, iterator++) {
97                if (lastchar == '/' && filename[0] == '.'
98                    && filename[1] != '.' && filename[1] != '/') {
99                    /* Leading dots are not permitted in plain DOS. */
100                    *iterator = '_';
101                } else {
102                    *iterator = *filename;
103                }
104                lastchar = *filename;
105            }
106            *iterator = '\0';
107            filename = newname;
108        }
109        file = fopen(filename, mode);
110
111        OPENSSL_free(newname);
112    }
113# else
114    file = fopen(filename, mode);
115# endif
116    return file;
117}
118
119#else
120
121void *openssl_fopen(const char *filename, const char *mode)
122{
123    return NULL;
124}
125
126#endif
127