funcs/func_base64.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 2005 - 2006, Digium, Inc.
   5  * Copyright (C) 2005, Claude Patry
   6  *
   7  * See http://www.asterisk.org for more information about
   8  * the Asterisk project. Please do not directly contact
   9  * any of the maintainers of this project for assistance;
  10  * the project provides a web site, mailing lists and IRC
  11  * channels for your use.
  12  *
  13  * This program is free software, distributed under the terms of
  14  * the GNU General Public License Version 2. See the LICENSE file
  15  * at the top of the source tree.
  16  */
  17
  18 /*! \file
  19  *
  20  * \brief Use the base64 as functions
  21  *
  22  * \ingroup functions
  23  */
  24
  25 /*** MODULEINFO
  26         <support_level>core</support_level>
  27  ***/
  28
  29 #include "asterisk.h"
  30
  31 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  32
  33 #include "asterisk/module.h"
  34 #include "asterisk/pbx.h"       /* function register/unregister */
  35 #include "asterisk/utils.h"
  36 #include "asterisk/strings.h"
  37
  38 /*** DOCUMENTATION
  39         <function name="BASE64_ENCODE" language="en_US">
  40                 <synopsis>
  41                         Encode a string in base64.
  42                 </synopsis>
  43                 <syntax>
  44                         <parameter name="string" required="true">
  45                                 <para>Input string</para>
  46                         </parameter>
  47                 </syntax>
  48                 <description>
  49                         <para>Returns the base64 string.</para>
  50                 </description>
  51                 <see-also>
  52                         <ref type="function">BASE64_DECODE</ref>
  53                         <ref type="function">AES_DECRYPT</ref>
  54                         <ref type="function">AES_ENCRYPT</ref>
  55                 </see-also>
  56         </function>
  57         <function name="BASE64_DECODE" language="en_US">
  58                 <synopsis>
  59                         Decode a base64 string.
  60                 </synopsis>
  61                 <syntax>
  62                         <parameter name="string" required="true">
  63                                 <para>Input string.</para>
  64                         </parameter>
  65                 </syntax>
  66                 <description>
  67                         <para>Returns the plain text string.</para>
  68                 </description>
  69                 <see-also>
  70                         <ref type="function">BASE64_ENCODE</ref>
  71                         <ref type="function">AES_DECRYPT</ref>
  72                         <ref type="function">AES_ENCRYPT</ref>
  73                 </see-also>
  74         </function>
  75  ***/
  76
  77 static int base64_helper(struct ast_channel *chan, const char *cmd, char *data,
  78                          char *buf, struct ast_str **str, ssize_t len)
  79 {
  80         if (ast_strlen_zero(data)) {
  81                 ast_log(LOG_WARNING, "Syntax: %s(<data>) - missing argument!\n", cmd);
  82                 return -1;
  83         }
  84
  85         if (cmd[7] == 'E') {
  86                 if (buf) {
  87                         ast_base64encode(buf, (unsigned char *) data, strlen(data), len);
  88                 } else {
  89                         if (len >= 0) {
  90                                 ast_str_make_space(str, len ? len : ast_str_strlen(*str) + strlen(data) * 4 / 3 + 2);
  91                         }
  92                         ast_base64encode(ast_str_buffer(*str) + ast_str_strlen(*str), (unsigned char *) data, strlen(data), ast_str_size(*str) - ast_str_strlen(*str));
  93                         ast_str_update(*str);
  94                 }
  95         } else {
  96                 int decoded_len;
  97                 if (buf) {
  98                         decoded_len = ast_base64decode((unsigned char *) buf, data, len);
  99                         /* add a terminating null at the end of buf, or at the
 100                          * end of our decoded string, which ever is less */
 101                         buf[decoded_len <= (len - 1) ? decoded_len : len - 1] = '\0';
 102                 } else {
 103                         if (len >= 0) {
 104                                 ast_str_make_space(str, len ? len : ast_str_strlen(*str) + strlen(data) * 3 / 4 + 2);
 105                         }
 106                         decoded_len = ast_base64decode((unsigned char *) ast_str_buffer(*str) + ast_str_strlen(*str), data, ast_str_size(*str) - ast_str_strlen(*str));
 107                         if (len)
 108                                 /* add a terminating null at the end of our
 109                                  * buffer, or at the end of our decoded string,
 110                                  * which ever is less */
 111                                 ast_str_buffer(*str)[decoded_len <= (len - 1) ? decoded_len : len - 1] = '\0';
 112                         else
 113                                 /* space for the null is allocated above */
 114                                 ast_str_buffer(*str)[decoded_len] = '\0';
 115
 116                         ast_str_update(*str);
 117                 }
 118         }
 119
 120         return 0;
 121 }
 122
 123 static int base64_buf_helper(struct ast_channel *chan, const char *cmd, char *data,
 124                          char *buf, size_t len)
 125 {
 126         return base64_helper(chan, cmd, data, buf, NULL, len);
 127 }
 128
 129 static int base64_str_helper(struct ast_channel *chan, const char *cmd, char *data,
 130                          struct ast_str **buf, ssize_t len)
 131 {
 132         return base64_helper(chan, cmd, data, NULL, buf, len);
 133 }
 134
 135 static struct ast_custom_function base64_encode_function = {
 136         .name = "BASE64_ENCODE",
 137         .read = base64_buf_helper,
 138         .read2 = base64_str_helper,
 139 };
 140
 141 static struct ast_custom_function base64_decode_function = {
 142         .name = "BASE64_DECODE",
 143         .read = base64_buf_helper,
 144         .read2 = base64_str_helper,
 145 };
 146
 147 static int unload_module(void)
 148 {
 149         return ast_custom_function_unregister(&base64_encode_function) |
 150                 ast_custom_function_unregister(&base64_decode_function);
 151 }
 152
 153 static int load_module(void)
 154 {
 155         return ast_custom_function_register(&base64_encode_function) |
 156                 ast_custom_function_register(&base64_decode_function);
 157 }
 158
 159 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "base64 encode/decode dialplan functions");