2.11BSD#431 - /usr/src/libexec/tcpd/eval.c

   1:  /*
   2:   * Routines for controlled evaluation of host names, user names, and so on.
   3:   * They are, in fact, wrappers around the functions that are specific for
   4:   * the sockets or TLI programming interfaces. The request_info and host_info
   5:   * structures are used for result cacheing.
   6:   *
   7:   * These routines allows us to postpone expensive operations until their
   8:   * results are really needed. Examples are hostname lookups and double
   9:   * checks, or username lookups. Information that cannot be retrieved is
  10:   * given the value "unknown" ("paranoid" in case of hostname problems).
  11:   *
  12:   * When ALWAYS_HOSTNAME is off, hostname lookup is done only when required by
  13:   * tcpd paranoid mode, by access control patterns, or by %letter expansions.
  14:   *
  15:   * When ALWAYS_RFC931 mode is off, user lookup is done only when required by
  16:   * access control patterns or %letter expansions.
  17:   *
  18:   * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
  19:   */
  20: 
  21: #ifndef lint
  22: static char sccsid[] = "@(#) eval.c 1.3 95/01/30 19:51:45";
  23: #endif
  24: 
  25: /* System libraries. */
  26: 
  27: #include <stdio.h>
  28: #include <string.h>
  29: 
  30: /* Local stuff. */
  31: 
  32: #include "tcpd.h"
  33: 
  34:  /*
  35:   * When a string has the value STRING_UNKNOWN, it means: don't bother, I
  36:   * tried to look up the data but it was unavailable for some reason. When a
  37:   * host name has the value STRING_PARANOID it means there was a name/address
  38:   * conflict.
  39:   */
  40: char    unknown[] = STRING_UNKNOWN;
  41: char    paranoid[] = STRING_PARANOID;
  42: 
  43: /* eval_user - look up user name */
  44: 
  45: char   *eval_user(request)
  46: struct request_info *request;
  47: {
  48:     if (request->user[0] == 0) {
  49:     strcpy(request->user, unknown);
  50:     if (request->sink == 0 && request->client->sin && request->server->sin)
  51:         rfc931(request->client->sin, request->server->sin, request->user);
  52:     }
  53:     return (request->user);
  54: }
  55: 
  56: /* eval_hostaddr - look up printable address */
  57: 
  58: char   *eval_hostaddr(host)
  59: struct host_info *host;
  60: {
  61:     if (host->addr[0] == 0) {
  62:     strcpy(host->addr, unknown);
  63:     if (host->request->hostaddr != 0)
  64:         host->request->hostaddr(host);
  65:     }
  66:     return (host->addr);
  67: }
  68: 
  69: /* eval_hostname - look up host name */
  70: 
  71: char   *eval_hostname(host)
  72: struct host_info *host;
  73: {
  74:     if (host->name[0] == 0) {
  75:     strcpy(host->name, unknown);
  76:     if (host->request->hostname != 0)
  77:         host->request->hostname(host);
  78:     }
  79:     return (host->name);
  80: }
  81: 
  82: /* eval_hostinfo - return string with host name (preferred) or address */
  83: 
  84: char   *eval_hostinfo(host)
  85: struct host_info *host;
  86: {
  87:     char   *hostname;
  88: 
  89: #ifndef ALWAYS_HOSTNAME             /* no implicit host lookups */
  90:     if (host->name[0] == 0)
  91:     return (eval_hostaddr(host));
  92: #endif
  93:     hostname = eval_hostname(host);
  94:     if (HOSTNAME_KNOWN(hostname)) {
  95:     return (host->name);
  96:     } else {
  97:     return (eval_hostaddr(host));
  98:     }
  99: }
 100: 
 101: /* eval_client - return string with as much about the client as we know */
 102: 
 103: char   *eval_client(request)
 104: struct request_info *request;
 105: {
 106:     static char both[2 * STRING_LENGTH];
 107:     char   *hostinfo = eval_hostinfo(request->client);
 108: 
 109: #ifndef ALWAYS_RFC931               /* no implicit user lookups */
 110:     if (request->user[0] == 0)
 111:     return (hostinfo);
 112: #endif
 113:     if (STR_NE(eval_user(request), unknown)) {
 114:     sprintf(both, "%s@%s", request->user, hostinfo);
 115:     return (both);
 116:     } else {
 117:     return (hostinfo);
 118:     }
 119: }
 120: 
 121: /* eval_server - return string with as much about the server as we know */
 122: 
 123: char   *eval_server(request)
 124: struct request_info *request;
 125: {
 126:     static char both[2 * STRING_LENGTH];
 127:     char   *host = eval_hostinfo(request->server);
 128:     char   *daemon = eval_daemon(request);
 129: 
 130:     if (STR_NE(host, unknown)) {
 131:     sprintf(both, "%s@%s", daemon, host);
 132:     return (both);
 133:     } else {
 134:     return (daemon);
 135:     }
 136: }

Defined functions

Defined variables