crypto/o_fopen.c

   1 /*
   2  * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (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 "internal/cryptlib.h"
  29
  30 #if !defined(OPENSSL_NO_STDIO)
  31
  32 # include <stdio.h>
  33 # ifdef _WIN32
  34 #  include <windows.h>
  35 # endif
  36 # ifdef __DJGPP__
  37 #  include <unistd.h>
  38 # endif
  39
  40 FILE *openssl_fopen(const char *filename, const char *mode)
  41 {
  42     FILE *file = NULL;
  43 # if defined(_WIN32) && defined(CP_UTF8)
  44     int sz, len_0 = (int)strlen(filename) + 1;
  45     DWORD flags;
  46
  47     /*
  48      * Basically there are three cases to cover: a) filename is
  49      * pure ASCII string; b) actual UTF-8 encoded string and
  50      * c) locale-ized string, i.e. one containing 8-bit
  51      * characters that are meaningful in current system locale.
  52      * If filename is pure ASCII or real UTF-8 encoded string,
  53      * MultiByteToWideChar succeeds and _wfopen works. If
  54      * filename is locale-ized string, chances are that
  55      * MultiByteToWideChar fails reporting
  56      * ERROR_NO_UNICODE_TRANSLATION, in which case we fall
  57      * back to fopen...
  58      */
  59     if ((sz = MultiByteToWideChar(CP_UTF8, (flags = MB_ERR_INVALID_CHARS),
  60                                   filename, len_0, NULL, 0)) > 0 ||
  61         (GetLastError() == ERROR_INVALID_FLAGS &&
  62          (sz = MultiByteToWideChar(CP_UTF8, (flags = 0),
  63                                    filename, len_0, NULL, 0)) > 0)
  64         ) {
  65         WCHAR wmode[8];
  66         WCHAR *wfilename = _alloca(sz * sizeof(WCHAR));
  67
  68         if (MultiByteToWideChar(CP_UTF8, flags,
  69                                 filename, len_0, wfilename, sz) &&
  70             MultiByteToWideChar(CP_UTF8, 0, mode, strlen(mode) + 1,
  71                                 wmode, OSSL_NELEM(wmode)) &&
  72             (file = _wfopen(wfilename, wmode)) == NULL &&
  73             (errno == ENOENT || errno == EBADF)
  74             ) {
  75             /*
  76              * UTF-8 decode succeeded, but no file, filename
  77              * could still have been locale-ized...
  78              */
  79             file = fopen(filename, mode);
  80         }
  81     } else if (GetLastError() == ERROR_NO_UNICODE_TRANSLATION) {
  82         file = fopen(filename, mode);
  83     }
  84 # elif defined(__DJGPP__)
  85     {
  86         char *newname = NULL;
  87
  88         if (pathconf(filename, _PC_NAME_MAX) <= 12) {  /* 8.3 file system? */
  89             char *iterator;
  90             char lastchar;
  91
  92             if ((newname = OPENSSL_malloc(strlen(filename) + 1)) == NULL) {
  93                 CRYPTOerr(CRYPTO_F_OPENSSL_FOPEN, ERR_R_MALLOC_FAILURE);
  94                 return NULL;
  95             }
  96
  97             for (iterator = newname, lastchar = '\0';
  98                 *filename; filename++, iterator++) {
  99                 if (lastchar == '/' && filename[0] == '.'
 100                     && filename[1] != '.' && filename[1] != '/') {
 101                     /* Leading dots are not permitted in plain DOS. */
 102                     *iterator = '_';
 103                 } else {
 104                     *iterator = *filename;
 105                 }
 106                 lastchar = *filename;
 107             }
 108             *iterator = '\0';
 109             filename = newname;
 110         }
 111         file = fopen(filename, mode);
 112
 113         OPENSSL_free(newname);
 114     }
 115 # else
 116     file = fopen(filename, mode);
 117 # endif
 118     return file;
 119 }
 120
 121 #else
 122
 123 void *openssl_fopen(const char *filename, const char *mode)
 124 {
 125     return NULL;
 126 }
 127
 128 #endif