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/* $OpenBSD: eval.c,v 1.4 2009/10/27 23:59:30 deraadt Exp $ */
/*
* Routines for controlled evaluation of host names, user names, and so on.
* They are, in fact, wrappers around the functions that are specific for
* the sockets or TLI programming interfaces. The request_info and host_info
* structures are used for result cacheing.
*
* These routines allows us to postpone expensive operations until their
* results are really needed. Examples are hostname lookups and double
* checks, or username lookups. Information that cannot be retrieved is
* given the value "unknown" ("paranoid" in case of hostname problems).
*
* When ALWAYS_HOSTNAME is off, hostname lookup is done only when required by
* tcpd paranoid mode, by access control patterns, or by %letter expansions.
*
* When ALWAYS_RFC931 mode is off, user lookup is done only when required by
* access control patterns or %letter expansions.
*
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
*/
/* System libraries. */
#include <stdio.h>
#include <string.h>
/* Local stuff. */
#include "tcpd.h"
/*
* When a string has the value STRING_UNKNOWN, it means: don't bother, I
* tried to look up the data but it was unavailable for some reason. When a
* host name has the value STRING_PARANOID it means there was a name/address
* conflict.
*/
char unknown[] = STRING_UNKNOWN;
char paranoid[] = STRING_PARANOID;
/* eval_user - look up user name */
char *eval_user(request)
struct request_info *request;
{
if (request->user[0] == 0) {
strlcpy(request->user, unknown, sizeof(request->user));
if (request->sink == 0 && request->client->sin && request->server->sin)
rfc931(request->client->sin, request->server->sin, request->user);
}
return (request->user);
}
/* eval_hostaddr - look up printable address */
char *eval_hostaddr(host)
struct host_info *host;
{
if (host->addr[0] == 0) {
strlcpy(host->addr, unknown, sizeof(host->addr));
if (host->request->hostaddr != 0)
host->request->hostaddr(host);
}
return (host->addr);
}
/* eval_hostname - look up host name */
char *eval_hostname(host)
struct host_info *host;
{
if (host->name[0] == 0) {
strlcpy(host->name, unknown, sizeof(host->name));
if (host->request->hostname != 0)
host->request->hostname(host);
}
return (host->name);
}
/* eval_hostinfo - return string with host name (preferred) or address */
char *eval_hostinfo(host)
struct host_info *host;
{
char *hostname;
#ifndef ALWAYS_HOSTNAME /* no implicit host lookups */
if (host->name[0] == 0)
return (eval_hostaddr(host));
#endif
hostname = eval_hostname(host);
if (HOSTNAME_KNOWN(hostname)) {
return (host->name);
} else {
return (eval_hostaddr(host));
}
}
/* eval_client - return string with as much about the client as we know */
char *eval_client(request)
struct request_info *request;
{
static char both[2 * STRING_LENGTH];
char *hostinfo = eval_hostinfo(request->client);
#ifndef ALWAYS_RFC931 /* no implicit user lookups */
if (request->user[0] == 0)
return (hostinfo);
#endif
if (STR_NE(eval_user(request), unknown)) {
snprintf(both, sizeof both, "%s@%s", request->user, hostinfo);
return (both);
} else {
return (hostinfo);
}
}
/* eval_server - return string with as much about the server as we know */
char *eval_server(request)
struct request_info *request;
{
static char both[2 * STRING_LENGTH];
char *host = eval_hostinfo(request->server);
char *daemon = eval_daemon(request);
if (STR_NE(host, unknown)) {
snprintf(both, sizeof both, "%s@%s", daemon, host);
return (both);
} else {
return (daemon);
}
}
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