lib/util/util_str_escape.c

   1 /*
   2    Samba string escaping routines
   3
   4    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2017
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "replace.h"
  21 #include "lib/util/debug.h"
  22 #include "lib/util/util_str_escape.h"
  23
  24
  25 /*
  26  * Calculate the encoded length of a character for log_escape
  27  *
  28  */
  29 static size_t encoded_length(unsigned char c)
  30 {
  31         if (c != '\\' &&  c > 0x1F) {
  32                 return 1;
  33         } else {
  34                 switch (c) {
  35                 case '\a':
  36                 case '\b':
  37                 case '\f':
  38                 case '\n':
  39                 case '\r':
  40                 case '\t':
  41                 case '\v':
  42                 case '\\':
  43                         return 2;  /* C escape sequence */
  44                 default:
  45                         return 4;  /* hex escape \xhh   */
  46                 }
  47         }
  48 }
  49
  50 /*
  51  * Escape any control characters in the inputs to prevent them from
  52  * interfering with the log output.
  53  */
  54 char *log_escape(TALLOC_CTX *frame, const char *in)
  55 {
  56         size_t size = 0;        /* Space to allocate for the escaped data */
  57         char *encoded = NULL;   /* The encoded string                     */
  58         const char *c;
  59         char *e;
  60
  61         if (in == NULL) {
  62                 return NULL;
  63         }
  64
  65         /* Calculate the size required for the escaped array */
  66         c = in;
  67         while (*c) {
  68                 size += encoded_length( *c);
  69                 c++;
  70         }
  71         size++;
  72
  73         encoded = talloc_array( frame, char, size);
  74         if (encoded == NULL) {
  75                 DBG_ERR( "Out of memory allocating encoded string\n");
  76                 return NULL;
  77         }
  78
  79         c = in;
  80         e = encoded;
  81         while (*c) {
  82                 if (*c != '\\' && (unsigned char)(*c) > 0x1F) {
  83                         *e++ = *c++;
  84                 } else {
  85                         switch (*c) {
  86                         case '\a':
  87                                 *e++ = '\\';
  88                                 *e++ = 'a';
  89                                 break;
  90                         case '\b':
  91                                 *e++ = '\\';
  92                                 *e++ = 'b';
  93                                 break;
  94                         case '\f':
  95                                 *e++ = '\\';
  96                                 *e++ = 'f';
  97                                 break;
  98                         case '\n':
  99                                 *e++ = '\\';
 100                                 *e++ = 'n';
 101                                 break;
 102                         case '\r':
 103                                 *e++ = '\\';
 104                                 *e++ = 'r';
 105                                 break;
 106                         case '\t':
 107                                 *e++ = '\\';
 108                                 *e++ = 't';
 109                                 break;
 110                         case '\v':
 111                                 *e++ = '\\';
 112                                 *e++ = 'v';
 113                                 break;
 114                         case '\\':
 115                                 *e++ = '\\';
 116                                 *e++ = '\\';
 117                                 break;
 118                         default:
 119                                 snprintf(e, 5, "\\x%02hhX", (unsigned char)(*c));
 120                                 e += 4;
 121                         }
 122                         c++;
 123                 }
 124         }
 125         *e = '\0';
 126         return encoded;
 127 }