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 <sys/types.h>
  10 #include <h/utils.h>
  11 #include <string.h>
  12 #include <stdlib.h>
  13
  14 static void
  15 escape_component (char *name, size_t namesize, char *chars);
  16
  17
  18 void
  19 escape_display_name (char *name, size_t namesize) {
  20   char *specials = "\"(),.:;<>@[\\]";
  21   escape_component (name, namesize, specials);
  22 }
  23
  24
  25 void
  26 escape_local_part (char *name, size_t namesize) {
  27   /* wsp (whitespace) is horizontal tab or space, according to
  28      RFC 5234. */
  29   char *specials_less_dot_plus_wsp = "   \"(),:;<>@[\\]";
  30   escape_component (name, namesize, specials_less_dot_plus_wsp);
  31 }
  32
  33
  34 /* Escape an address component, hopefully per RFC 5322.  Assumes
  35    one-byte characters.  The char array pointed to by the name
  36    argument is modified in place.  Its size is specified by the
  37    namesize argument.  The need_escape argument is a string of
  38    characters that require that name be escaped. */
  39 void
  40 escape_component (char *name, size_t namesize, char *chars_to_escape) {
  41     /* If name contains any chars_to_escape:
  42        1) enclose it in ""
  43        2) escape any embedded "
  44      */
  45     if (strpbrk(name, chars_to_escape)) {
  46         char *destp, *srcp;
  47         /* Maximum space requirement would be if each character had
  48            to be escaped, plus enclosing double quotes, plus null termintor.
  49            E.g., 2 characters, "", would require 7, "\"\""0, where that 0
  50            is '\0'. */
  51         char *tmp = mh_xmalloc (2*strlen(name) + 3);
  52
  53         for (destp = tmp, srcp = name; *srcp; ++srcp) {
  54             if (srcp == name) {
  55                 /* Insert initial double quote, if needed. */
  56                 if (*srcp != '"') {
  57                     *destp++ = '"';
  58                 }
  59             } else {
  60                 /* Escape embedded, unescaped double quote. */
  61                 if (*srcp == '"' && *(srcp+1) != '\0' && *(srcp-1) != '\\') {
  62                     *destp++ = '\\';
  63                 }
  64             }
  65
  66             *destp++ = *srcp;
  67
  68             /* End of name. */
  69             if (*(srcp+1) == '\0') {
  70                 /* Insert final double quote, if needed. */
  71                 if (*srcp != '"') {
  72                     *destp++ = '"';
  73                 }
  74
  75                 *destp++ = '\0';
  76             }
  77         }
  78
  79         if (strcmp (tmp, "\"")) {
  80             /* assert (strlen(tmp) + 1 == destp - tmp); */
  81             size_t len = destp - tmp;
  82             strncpy (name, tmp, len <= namesize  ?  len  :  namesize);
  83         } else {
  84             /* Handle just " as special case here instead of above. */
  85             strncpy (name, "\"\\\"\"", namesize);
  86         }
  87
  88         name[namesize - 1] = '\0';
  89
  90         free (tmp);
  91     }
  92 }