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 "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
  38 FILE *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                 CRYPTOerr(CRYPTO_F_OPENSSL_FOPEN, 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
 121 void *openssl_fopen(const char *filename, const char *mode)
 122 {
 123     return NULL;
 124 }
 125
 126 #endif