external/ibm-public/postfix/dist/src/trivial-rewrite/rewrite.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      rewrite 3
   6 /* SUMMARY
   7 /*      mail address rewriter
   8 /* SYNOPSIS
   9 /*      #include "trivial-rewrite.h"
  10 /*
  11 /*      void    rewrite_init(void)
  12 /*
  13 /*      void    rewrite_proto(stream)
  14 /*      VSTREAM *stream;
  15 /*
  16 /*      void    rewrite_addr(context, addr, result)
  17 /*      RWR_CONTEXT *context;
  18 /*      char    *addr;
  19 /*      VSTRING *result;
  20 /*
  21 /*      void    rewrite_tree(context, tree)
  22 /*      RWR_CONTEXT *context;
  23 /*      TOK822  *tree;
  24 /*
  25 /*      RWR_CONTEXT local_context;
  26 /*      RWR_CONTEXT remote_context;
  27 /* DESCRIPTION
  28 /*      This module implements the trivial address rewriting engine.
  29 /*
  30 /*      rewrite_init() initializes data structures that are private
  31 /*      to this module. It should be called once before using the
  32 /*      actual rewriting routines.
  33 /*
  34 /*      rewrite_proto() implements the client-server protocol: read
  35 /*      one rule set name and one address in external (quoted) form,
  36 /*      reply with the rewritten address in external form.
  37 /*
  38 /*      rewrite_addr() rewrites an address string to another string.
  39 /*      Both input and output are in external (quoted) form.
  40 /*
  41 /*      rewrite_tree() rewrites a parse tree with a single address to
  42 /*      another tree.  A tree is a dummy node on top of a token list.
  43 /*
  44 /*      local_context and remote_context provide domain names for
  45 /*      completing incomplete address forms.
  46 /* STANDARDS
  47 /* DIAGNOSTICS
  48 /*      Problems and transactions are logged to the syslog daemon.
  49 /* BUGS
  50 /* SEE ALSO
  51 /* LICENSE
  52 /* .ad
  53 /* .fi
  54 /*      The Secure Mailer license must be distributed with this software.
  55 /* AUTHOR(S)
  56 /*      Wietse Venema
  57 /*      IBM T.J. Watson Research
  58 /*      P.O. Box 704
  59 /*      Yorktown Heights, NY 10598, USA
  60 /*--*/
  61
  62 /* System library. */
  63
  64 #include <sys_defs.h>
  65 #include <stdlib.h>
  66 #include <string.h>
  67
  68 /* Utility library. */
  69
  70 #include <msg.h>
  71 #include <vstring.h>
  72 #include <vstream.h>
  73 #include <vstring_vstream.h>
  74 #include <split_at.h>
  75
  76 /* Global library. */
  77
  78 #include <mail_params.h>
  79 #include <mail_proto.h>
  80 #include <resolve_local.h>
  81 #include <tok822.h>
  82 #include <mail_conf.h>
  83
  84 /* Application-specific. */
  85
  86 #include "trivial-rewrite.h"
  87
  88 RWR_CONTEXT local_context = {
  89     VAR_MYORIGIN, &var_myorigin,
  90     VAR_MYDOMAIN, &var_mydomain,
  91 };
  92
  93 RWR_CONTEXT remote_context = {
  94     VAR_REM_RWR_DOMAIN, &var_remote_rwr_domain,
  95     VAR_REM_RWR_DOMAIN, &var_remote_rwr_domain,
  96 };
  97
  98 static VSTRING *ruleset;
  99 static VSTRING *address;
 100 static VSTRING *result;
 101
 102 /* rewrite_tree - rewrite address according to rule set */
 103
 104 void    rewrite_tree(RWR_CONTEXT *context, TOK822 *tree)
 105 {
 106     TOK822 *colon;
 107     TOK822 *domain;
 108     TOK822 *bang;
 109     TOK822 *local;
 110
 111     /*
 112      * XXX If you change this module, quote_822_local.c, or tok822_parse.c,
 113      * be sure to re-run the tests under "make rewrite_clnt_test" and "make
 114      * resolve_clnt_test" in the global directory.
 115      */
 116
 117     /*
 118      * Sanity check.
 119      */
 120     if (tree->head == 0)
 121         msg_panic("rewrite_tree: empty tree");
 122
 123     /*
 124      * An empty address is a special case.
 125      */
 126     if (tree->head == tree->tail
 127         && tree->tail->type == TOK822_QSTRING
 128         && VSTRING_LEN(tree->tail->vstr) == 0)
 129         return;
 130
 131     /*
 132      * Treat a lone @ as if it were an empty address.
 133      */
 134     if (tree->head == tree->tail
 135         && tree->tail->type == '@') {
 136         tok822_free_tree(tok822_sub_keep_before(tree, tree->tail));
 137         tok822_sub_append(tree, tok822_alloc(TOK822_QSTRING, ""));
 138         return;
 139     }
 140
 141     /*
 142      * Strip source route.
 143      */
 144     if (tree->head->type == '@'
 145         && (colon = tok822_find_type(tree->head, ':')) != 0
 146         && colon != tree->tail)
 147         tok822_free_tree(tok822_sub_keep_after(tree, colon));
 148
 149     /*
 150      * Optionally, transform address forms without @.
 151      */
 152     if ((domain = tok822_rfind_type(tree->tail, '@')) == 0) {
 153
 154         /*
 155          * Swap domain!user to user@domain.
 156          */
 157         if (var_swap_bangpath != 0
 158             && (bang = tok822_find_type(tree->head, '!')) != 0) {
 159             tok822_sub_keep_before(tree, bang);
 160             local = tok822_cut_after(bang);
 161             tok822_free(bang);
 162             tok822_sub_prepend(tree, tok822_alloc('@', (char *) 0));
 163             if (local)
 164                 tok822_sub_prepend(tree, local);
 165         }
 166
 167         /*
 168          * Promote user%domain to user@domain.
 169          */
 170         else if (var_percent_hack != 0
 171                  && (domain = tok822_rfind_type(tree->tail, '%')) != 0) {
 172             domain->type = '@';
 173         }
 174
 175         /*
 176          * Append missing @origin
 177          */
 178         else if (var_append_at_myorigin != 0
 179                  && REW_PARAM_VALUE(context->origin) != 0
 180                  && REW_PARAM_VALUE(context->origin)[0] != 0) {
 181             domain = tok822_sub_append(tree, tok822_alloc('@', (char *) 0));
 182             tok822_sub_append(tree, tok822_scan(REW_PARAM_VALUE(context->origin),
 183                                                 (TOK822 **) 0));
 184         }
 185     }
 186
 187     /*
 188      * Append missing .domain, but leave broken forms ending in @ alone. This
 189      * merely makes diagnostics more accurate by leaving bogus addresses
 190      * alone.
 191      */
 192     if (var_append_dot_mydomain != 0
 193         && REW_PARAM_VALUE(context->domain) != 0
 194         && REW_PARAM_VALUE(context->domain)[0] != 0
 195         && (domain = tok822_rfind_type(tree->tail, '@')) != 0
 196         && domain != tree->tail
 197         && tok822_find_type(domain, TOK822_DOMLIT) == 0
 198         && tok822_find_type(domain, '.') == 0) {
 199         tok822_sub_append(tree, tok822_alloc('.', (char *) 0));
 200         tok822_sub_append(tree, tok822_scan(REW_PARAM_VALUE(context->domain),
 201                                             (TOK822 **) 0));
 202     }
 203
 204     /*
 205      * Strip trailing dot at end of domain, but not dot-dot or @-dot. This
 206      * merely makes diagnostics more accurate by leaving bogus addresses
 207      * alone.
 208      */
 209     if (tree->tail->type == '.'
 210         && tree->tail->prev
 211         && tree->tail->prev->type != '.'
 212         && tree->tail->prev->type != '@')
 213         tok822_free_tree(tok822_sub_keep_before(tree, tree->tail));
 214 }
 215
 216 /* rewrite_proto - read request and send reply */
 217
 218 int     rewrite_proto(VSTREAM *stream)
 219 {
 220     RWR_CONTEXT *context;
 221     TOK822 *tree;
 222
 223     if (attr_scan(stream, ATTR_FLAG_STRICT,
 224                   ATTR_TYPE_STR, MAIL_ATTR_RULE, ruleset,
 225                   ATTR_TYPE_STR, MAIL_ATTR_ADDR, address,
 226                   ATTR_TYPE_END) != 2)
 227         return (-1);
 228
 229     if (strcmp(vstring_str(ruleset), MAIL_ATTR_RWR_LOCAL) == 0)
 230         context = &local_context;
 231     else if (strcmp(vstring_str(ruleset), MAIL_ATTR_RWR_REMOTE) == 0)
 232         context = &remote_context;
 233     else {
 234         msg_warn("unknown context: %s", vstring_str(ruleset));
 235         return (-1);
 236     }
 237
 238     /*
 239      * Sanity check. An address is supposed to be in externalized form.
 240      */
 241     if (*vstring_str(address) == 0) {
 242         msg_warn("rewrite_addr: null address");
 243         vstring_strcpy(result, vstring_str(address));
 244     }
 245
 246     /*
 247      * Convert the address from externalized (quoted) form to token list,
 248      * rewrite it, and convert back.
 249      */
 250     else {
 251         tree = tok822_scan_addr(vstring_str(address));
 252         rewrite_tree(context, tree);
 253         tok822_externalize(result, tree, TOK822_STR_DEFL);
 254         tok822_free_tree(tree);
 255     }
 256     if (msg_verbose)
 257         msg_info("`%s' `%s' -> `%s'", vstring_str(ruleset),
 258                  vstring_str(address), vstring_str(result));
 259
 260     attr_print(stream, ATTR_FLAG_NONE,
 261                ATTR_TYPE_INT, MAIL_ATTR_FLAGS, server_flags,
 262                ATTR_TYPE_STR, MAIL_ATTR_ADDR, vstring_str(result),
 263                ATTR_TYPE_END);
 264
 265     if (vstream_fflush(stream) != 0) {
 266         msg_warn("write rewrite reply: %m");
 267         return (-1);
 268     }
 269     return (0);
 270 }
 271
 272 /* rewrite_init - module initializations */
 273
 274 void    rewrite_init(void)
 275 {
 276     ruleset = vstring_alloc(100);
 277     address = vstring_alloc(100);
 278     result = vstring_alloc(100);
 279 }