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 {
  17   char *specials = "\"(),.:;<>@[\\]";
  18   escape_component (name, namesize, specials);
  19 }
  20
  21
  22 void
  23 escape_local_part (char *name, size_t namesize)
  24 {
  25   /* wsp (whitespace) is horizontal tab or space, according to
  26      RFC 5234. */
  27   char *specials_less_dot_plus_wsp = "   \"(),:;<>@[\\]";
  28   escape_component (name, namesize, specials_less_dot_plus_wsp);
  29 }
  30
  31
  32 /* Escape an address component, hopefully per RFC 5322.  Assumes
  33    one-byte characters.  The char array pointed to by the name
  34    argument is modified in place.  Its size is specified by the
  35    namesize argument.  The need_escape argument is a string of
  36    characters that require that name be escaped. */
  37 static void
  38 escape_component (char *name, size_t namesize, char *chars_to_escape)
  39 {
  40     /* If name contains any chars_to_escape:
  41        1) enclose it in ""
  42        2) escape any embedded "
  43      */
  44     if (strpbrk(name, chars_to_escape)) {
  45         char *destp, *srcp;
  46         /* Maximum space requirement would be if each character had
  47            to be escaped, plus enclosing double quotes, plus NUL terminator.
  48            E.g., 2 characters, "", would require 7, "\"\""0, where that 0
  49            is '\0'. */
  50         char *tmp = mh_xmalloc (2*strlen(name) + 3);
  51
  52         for (destp = tmp, srcp = name; *srcp; ++srcp) {
  53             if (srcp == name) {
  54                 /* Insert initial double quote, if needed. */
  55                 if (*srcp != '"') {
  56                     *destp++ = '"';
  57                 }
  58             } else {
  59                 /* Escape embedded, unescaped double quote. */
  60                 if (*srcp == '"' && *(srcp+1) != '\0' && *(srcp-1) != '\\') {
  61                     *destp++ = '\\';
  62                 }
  63             }
  64
  65             *destp++ = *srcp;
  66
  67             /* End of name. */
  68             if (*(srcp+1) == '\0') {
  69                 /* Insert final double quote, if needed. */
  70                 if (*srcp != '"') {
  71                     *destp++ = '"';
  72                 }
  73
  74                 *destp++ = '\0';
  75             }
  76         }
  77
  78         if (strcmp (tmp, "\"")) {
  79             size_t len = destp - tmp;
  80             assert ((ssize_t) strlen(tmp) + 1 == destp - tmp);
  81             strncpy (name, tmp, min(len, namesize));
  82         } else {
  83             /* Handle just " as special case here instead of above. */
  84             strncpy (name, "\"\\\"\"", namesize);
  85         }
  86
  87         name[namesize - 1] = '\0';
  88
  89         free (tmp);
  90     }
  91 }