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/nmh.h>
   9 #include <h/utils.h>
  10
  11 static void
  12 escape_component (char *name, size_t namesize, char *chars);
  13
  14
  15 void
  16 escape_display_name (char *name, size_t namesize) {
  17   char *specials = "\"(),.:;<>@[\\]";
  18   escape_component (name, namesize, specials);
  19 }
  20
  21
  22 void
  23 escape_local_part (char *name, size_t namesize) {
  24   /* wsp (whitespace) is horizontal tab or space, according to
  25      RFC 5234. */
  26   char *specials_less_dot_plus_wsp = "   \"(),:;<>@[\\]";
  27   escape_component (name, namesize, specials_less_dot_plus_wsp);
  28 }
  29
  30
  31 /* Escape an address component, hopefully per RFC 5322.  Assumes
  32    one-byte characters.  The char array pointed to by the name
  33    argument is modified in place.  Its size is specified by the
  34    namesize argument.  The need_escape argument is a string of
  35    characters that require that name be escaped. */
  36 void
  37 escape_component (char *name, size_t namesize, char *chars_to_escape) {
  38     /* If name contains any chars_to_escape:
  39        1) enclose it in ""
  40        2) escape any embedded "
  41      */
  42     if (strpbrk(name, chars_to_escape)) {
  43         char *destp, *srcp;
  44         /* Maximum space requirement would be if each character had
  45            to be escaped, plus enclosing double quotes, plus null termintor.
  46            E.g., 2 characters, "", would require 7, "\"\""0, where that 0
  47            is '\0'. */
  48         char *tmp = mh_xmalloc (2*strlen(name) + 3);
  49
  50         for (destp = tmp, srcp = name; *srcp; ++srcp) {
  51             if (srcp == name) {
  52                 /* Insert initial double quote, if needed. */
  53                 if (*srcp != '"') {
  54                     *destp++ = '"';
  55                 }
  56             } else {
  57                 /* Escape embedded, unescaped double quote. */
  58                 if (*srcp == '"' && *(srcp+1) != '\0' && *(srcp-1) != '\\') {
  59                     *destp++ = '\\';
  60                 }
  61             }
  62
  63             *destp++ = *srcp;
  64
  65             /* End of name. */
  66             if (*(srcp+1) == '\0') {
  67                 /* Insert final double quote, if needed. */
  68                 if (*srcp != '"') {
  69                     *destp++ = '"';
  70                 }
  71
  72                 *destp++ = '\0';
  73             }
  74         }
  75
  76         if (strcmp (tmp, "\"")) {
  77             size_t len = destp - tmp;
  78             assert ((ssize_t) strlen(tmp) + 1 == destp - tmp);
  79             strncpy (name, tmp, len <= namesize  ?  len  :  namesize);
  80         } else {
  81             /* Handle just " as special case here instead of above. */
  82             strncpy (name, "\"\\\"\"", namesize);
  83         }
  84
  85         name[namesize - 1] = '\0';
  86
  87         free (tmp);
  88     }
  89 }