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

   1 /*
   2  * escape_addresses.c -- Escape address components, hopefully per RFC 5322.
   3  *
   4  * This code is Copyright (c) 2012, by the authors of nmh.  See the
   5  * COPYRIGHT file in the root directory of the nmh distribution for
   6  * complete copyright information.
   7  */
   8
   9 #include <h/nmh.h>
  10 #include <h/utils.h>
  11
  12 static void
  13 escape_component (char *name, size_t namesize, char *chars);
  14
  15
  16 void
  17 escape_display_name (char *name, size_t namesize) {
  18   char *specials = "\"(),.:;<>@[\\]";
  19   escape_component (name, namesize, specials);
  20 }
  21
  22
  23 void
  24 escape_local_part (char *name, size_t namesize) {
  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 void
  38 escape_component (char *name, size_t namesize, char *chars_to_escape) {
  39     /* If name contains any chars_to_escape:
  40        1) enclose it in ""
  41        2) escape any embedded "
  42      */
  43     if (strpbrk(name, chars_to_escape)) {
  44         char *destp, *srcp;
  45         /* Maximum space requirement would be if each character had
  46            to be escaped, plus enclosing double quotes, plus null termintor.
  47            E.g., 2 characters, "", would require 7, "\"\""0, where that 0
  48            is '\0'. */
  49         char *tmp = mh_xmalloc (2*strlen(name) + 3);
  50
  51         for (destp = tmp, srcp = name; *srcp; ++srcp) {
  52             if (srcp == name) {
  53                 /* Insert initial double quote, if needed. */
  54                 if (*srcp != '"') {
  55                     *destp++ = '"';
  56                 }
  57             } else {
  58                 /* Escape embedded, unescaped double quote. */
  59                 if (*srcp == '"' && *(srcp+1) != '\0' && *(srcp-1) != '\\') {
  60                     *destp++ = '\\';
  61                 }
  62             }
  63
  64             *destp++ = *srcp;
  65
  66             /* End of name. */
  67             if (*(srcp+1) == '\0') {
  68                 /* Insert final double quote, if needed. */
  69                 if (*srcp != '"') {
  70                     *destp++ = '"';
  71                 }
  72
  73                 *destp++ = '\0';
  74             }
  75         }
  76
  77         if (strcmp (tmp, "\"")) {
  78             size_t len = destp - tmp;
  79             assert ((ssize_t) strlen(tmp) + 1 == destp - tmp);
  80             strncpy (name, tmp, len <= namesize  ?  len  :  namesize);
  81         } else {
  82             /* Handle just " as special case here instead of above. */
  83             strncpy (name, "\"\\\"\"", namesize);
  84         }
  85
  86         name[namesize - 1] = '\0';
  87
  88         free (tmp);
  89     }
  90 }