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/* $NetBSD: percent_x.c,v 1.5 2012/03/21 10:10:37 matt Exp $ */
/*
* percent_x() takes a string and performs %<char> expansions. It aborts the
* program when the expansion would overflow the output buffer. The result
* of %<char> expansion may be passed on to a shell process. For this
* reason, characters with a special meaning to shells are replaced by
* underscores.
*
* Diagnostics are reported through syslog(3).
*
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#) percent_x.c 1.4 94/12/28 17:42:37";
#else
__RCSID("$NetBSD: percent_x.c,v 1.5 2012/03/21 10:10:37 matt Exp $");
#endif
#endif
/* System libraries. */
#include <stdio.h>
#include <syslog.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
/* Local stuff. */
#include "tcpd.h"
/* percent_x - do %<char> expansion, abort if result buffer is too small */
char *
percent_x(char *result, int result_len, char *string,
struct request_info *request)
{
char *bp = result;
char *end = result + result_len - 1; /* end of result buffer */
char *expansion;
size_t expansion_len;
static const char ok_chars[] = "1234567890!@%-_=+:,./"
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
char *str = string;
char *cp;
int ch;
/*
* Warning: we may be called from a child process or after pattern
* matching, so we cannot use clean_exit() or tcpd_jump().
*/
while (*str) {
if (*str == '%' && (ch = str[1]) != 0) {
str += 2;
expansion =
ch == 'a' ? eval_hostaddr(request->client) :
ch == 'A' ? eval_hostaddr(request->server) :
ch == 'c' ? eval_client(request) :
ch == 'd' ? eval_daemon(request) :
ch == 'h' ? eval_hostinfo(request->client) :
ch == 'H' ? eval_hostinfo(request->server) :
ch == 'n' ? eval_hostname(request->client) :
ch == 'N' ? eval_hostname(request->server) :
ch == 'p' ? eval_pid(request) :
ch == 's' ? eval_server(request) :
ch == 'u' ? eval_user(request) :
ch == '%' ? __UNCONST("%")
: (tcpd_warn("unrecognized %%%c", ch), __UNCONST(""));
for (cp = expansion; *(cp += strspn(cp, ok_chars)); /* */ )
*cp = '_';
expansion_len = cp - expansion;
} else {
expansion = str++;
expansion_len = 1;
}
if (bp + expansion_len >= end) {
tcpd_warn("percent_x: expansion too long: %.30s...", result);
sleep(5);
exit(0);
}
memcpy(bp, expansion, expansion_len);
bp += expansion_len;
}
*bp = 0;
return (result);
}
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