diplodocus.org Git - nmh/blob - sbr/escape_addresses.c

   1 /* escape_addresses.c -- Escape address components, hopefully per RFC 5322.
   2  *
   3  * This code is Copyright (c) 2012, by the authors of nmh.  See the
   4  * COPYRIGHT file in the root directory of the nmh distribution for
   5  * complete copyright information.
   6  */
   7
   8 #include <h/mh.h>
   9 #include <h/utils.h>
  10
  11 static void escape_component (char *name, size_t namesize, char *chars);
  12
  13
  14 void
  15 escape_display_name (char *name, size_t namesize) {
  16   char *specials = "\"(),.:;<>@[\\]";
  17   escape_component (name, namesize, specials);
  18 }
  19
  20
  21 void
  22 escape_local_part (char *name, size_t namesize) {
  23   /* wsp (whitespace) is horizontal tab or space, according to
  24      RFC 5234. */
  25   char *specials_less_dot_plus_wsp = "   \"(),:;<>@[\\]";
  26   escape_component (name, namesize, specials_less_dot_plus_wsp);
  27 }
  28
  29
  30 /* Escape an address component, hopefully per RFC 5322.  Assumes
  31    one-byte characters.  The char array pointed to by the name
  32    argument is modified in place.  Its size is specified by the
  33    namesize argument.  The need_escape argument is a string of
  34    characters that require that name be escaped. */
  35 static void
  36 escape_component (char *name, size_t namesize, char *chars_to_escape) {
  37     /* If name contains any chars_to_escape:
  38        1) enclose it in ""
  39        2) escape any embedded "
  40      */
  41     if (strpbrk(name, chars_to_escape)) {
  42         char *destp, *srcp;
  43         /* Maximum space requirement would be if each character had
  44            to be escaped, plus enclosing double quotes, plus NUL terminator.
  45            E.g., 2 characters, "", would require 7, "\"\""0, where that 0
  46            is '\0'. */
  47         char *tmp = mh_xmalloc (2*strlen(name) + 3);
  48
  49         for (destp = tmp, srcp = name; *srcp; ++srcp) {
  50             if (srcp == name) {
  51                 /* Insert initial double quote, if needed. */
  52                 if (*srcp != '"') {
  53                     *destp++ = '"';
  54                 }
  55             } else {
  56                 /* Escape embedded, unescaped double quote. */
  57                 if (*srcp == '"' && *(srcp+1) != '\0' && *(srcp-1) != '\\') {
  58                     *destp++ = '\\';
  59                 }
  60             }
  61
  62             *destp++ = *srcp;
  63
  64             /* End of name. */
  65             if (*(srcp+1) == '\0') {
  66                 /* Insert final double quote, if needed. */
  67                 if (*srcp != '"') {
  68                     *destp++ = '"';
  69                 }
  70
  71                 *destp++ = '\0';
  72             }
  73         }
  74
  75         if (strcmp (tmp, "\"")) {
  76             size_t len = destp - tmp;
  77             assert ((ssize_t) strlen(tmp) + 1 == destp - tmp);
  78             strncpy (name, tmp, min(len, namesize));
  79         } else {
  80             /* Handle just " as special case here instead of above. */
  81             strncpy (name, "\"\\\"\"", namesize);
  82         }
  83
  84         name[namesize - 1] = '\0';
  85
  86         free (tmp);
  87     }
  88 }