I didn't like the DNS co-process design so I changed tinyproxy from a
threading model to a standard pre-forked model. This means I don't need the DNS co-process files. Gone.
This commit is contained in:
Robert James Kaes
parent
b3e657a00e
commit
1fda8899b1
208
src/dnsclient.c
208
src/dnsclient.c
@ -1,208 +0,0 @@
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/* $Id: dnsclient.c,v 1.2 2002-05-24 04:45:32 rjkaes Exp $
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*
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* Create the dnsserver child process, and then include functions to
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* retrieve IP addresses or host names. These functions are required
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* since the traditional gethostbyaddr() and getaddrbyname() functions
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* are not thread reentrant. By spawning a child process the blocking
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* has been moved outside the threads.
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*
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* Copyright (C) 2002 Robert James Kaes (rjkaes@flarenet.com)
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include "tinyproxy.h"
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#include "dnsclient.h"
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#include "heap.h"
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#include "log.h"
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#include "network.h"
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#include "text.h"
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/*
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* Static variable which holds the "dnsserver" process.
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*/
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static pid_t dnsserver_process;
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/*
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* Hold the location of the Unix socket for client communication.
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*/
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static char* unix_socket_loc;
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/*
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* Fork a copy of the "dnsserver" program. Two arguments are used
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* by this function: 'dnsserver_location' is the complete path to the
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* dnsserver executable; 'path' is the absolute path used by the
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* Unix socket.
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*/
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int
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start_dnsserver(const char* dnsserver_location, const char* path)
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{
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int ret;
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assert(dnsserver_location != NULL);
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assert(path != NULL);
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unix_socket_loc = safestrdup(path);
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if ((dnsserver_process = fork()) == 0) {
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/* Child process */
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chdir("/");
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umask(077);
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close(0);
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close(1);
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close(2);
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/* Start the "dnsserver" program */
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ret = execl(dnsserver_location,
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dnsserver_location,
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path,
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NULL);
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if (ret < 0)
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return -ENOEXEC;
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}
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/* Parent process */
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return 0;
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}
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/*
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* Stop the dnsserver process.
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*/
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int
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stop_dnsserver(void)
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{
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kill(dnsserver_process, SIGTERM);
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kill(dnsserver_process, SIGKILL);
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unlink(unix_socket_loc);
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return 0;
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}
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/*
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* Returns a socket connected to the "dnsserver"
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*/
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int
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dns_connect(void)
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{
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int dns;
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struct sockaddr_un addr;
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dns = socket(AF_LOCAL, SOCK_STREAM, 0);
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if (dns < 0)
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return -EIO;
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memset(&addr, 0, sizeof(addr));
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addr.sun_family = AF_LOCAL;
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strcpy(addr.sun_path, unix_socket_loc);
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if (connect(dns, (struct sockaddr *)&addr, sizeof(addr)) < 0)
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return -EIO;
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else
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return dns;
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}
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/*
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* Closes the connection to the "dnsserver"
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*/
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void
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dns_disconnect(int dns)
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{
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assert(dns >= 0);
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safe_write(dns, "$shutdown\n", 10);
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close(dns);
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}
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/*
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* Takes a dotted-decimal IP address and returns the host name in the
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* buffer supplied by the caller.
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*
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* Returns: 0 if the buffer is filled correctly, or
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* -1 if there was an error
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*/
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int
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dns_gethostbyaddr(int dns, const char* ipaddr, char** hostname,
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size_t hostlen)
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{
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char* buffer;
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ssize_t len;
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char *ptr;
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assert(dns >= 0);
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assert(ipaddr != NULL);
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assert(hostname != NULL);
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assert(hostlen > 0);
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write_message(dns, "%s\n", ipaddr);
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len = readline(dns, &buffer);
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if (len < 0)
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return len;
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chomp(buffer, len);
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if (strncmp(buffer, "$fail", 5) == 0) {
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/* There was a problem. */
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safefree(buffer);
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return -ENOMSG;
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}
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ptr = strchr(buffer, ' ');
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ptr++;
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strlcpy(*hostname, ptr, hostlen);
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safefree(buffer);
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return 0;
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}
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/*
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* Takes a host name and returns an array of IP addresses. The caller
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* is responsible for freeing the 'addresses' memory block.
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*/
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int
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dns_getaddrbyname(int dns, const char* name, struct in_addr** addresses)
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{
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char* buffer;
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ssize_t len;
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char *ptr;
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assert(dns >= 0);
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assert(name != NULL);
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assert(addresses != NULL);
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write_message(dns, "%s\n", name);
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len = readline(dns, &buffer);
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if (len < 0)
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return len;
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chomp(buffer, len);
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if (strncmp(buffer, "$fail", 5) == 0) {
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safefree(buffer);
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return -ENOMSG;
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}
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ptr = strchr(buffer + 6, ' ');
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if (ptr)
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*ptr = '\0';
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*addresses = safemalloc(sizeof(struct in_addr));
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if (!*addresses) {
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safefree(buffer);
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return -ENOMEM;
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}
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inet_aton(buffer + 6, *addresses);
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safefree(buffer);
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return 0;
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}
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@ -1,32 +0,0 @@
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/* $Id: dnsclient.h,v 1.1 2002-05-23 04:40:06 rjkaes Exp $
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*
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* See 'dnsclient.c' for a detailed description.
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*
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* Copyright (C) 2002 Robert James Kaes (rjkaes@flarenet.com)
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#ifndef TINYPROXY_DNSCLIENT_H
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#define TINYPROXY_DNSCLIENT_H
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extern int start_dnsserver(const char* dnsserver_location, const char* path);
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extern int stop_dnsserver(void);
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extern int dns_connect(void);
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extern void dns_disconnect(int dns);
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extern int dns_gethostbyaddr(int dns, const char* ipaddr, char** hostname,
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size_t hostlen);
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extern int dns_getaddrbyname(int dns, const char* name,
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struct in_addr** addresses);
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#endif
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242
src/dnsserver.c
242
src/dnsserver.c
@ -1,242 +0,0 @@
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/* $Id: dnsserver.c,v 1.1 2002-05-23 04:40:42 rjkaes Exp $
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*
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* This is a DNS resolver program. I've borrowed _liberally_ from
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* Squid's dnsserver program. Only one argument is passed to this
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* program (the path to the Unix socket.) Additionally, this program
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* will be started by tinyproxy itself.
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*
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* As noted, communication is conducted over a Unix socket. The
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* client opens a connection and writes a '\n' terminated string with
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* either a domain name (if an address is required) or a
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* dotted-decimal IP address (if the domain name is required.) This
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* program will then respond with a '\n' terminated string starting
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* with either "$addr" if IP addresses are being returned, or "$name"
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* if a host name is returned. The connection will remain open until
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* the "$shutdown" command is sent by the client.
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*
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* Copyright (C) 2002 Robert James Kaes (rjkaes@flarenet.com)
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include "common.h"
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#include "daemon.h"
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#include "heap.h"
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#include "network.h"
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#include "text.h"
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/*
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* Store a copy of the location of the Unix socket
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*/
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static char *unix_socket_path;
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/*
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* Handle SIGCHLD signals so that zombies are reaped.
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*/
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static void
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child_signal_handler(int signo)
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{
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pid_t pid;
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int status;
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while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
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;
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return;
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}
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/*
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* Handle the SIGTERM signal to remove the Unix socket
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*/
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static void
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term_signal_handler(int signo)
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{
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unlink(unix_socket_path);
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return;
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}
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/*
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* Text error messages for DNS problems.
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*/
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static char*
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dns_error_messages(int err)
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{
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if (err == HOST_NOT_FOUND)
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return "Host not found (authoritative)";
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else if (err == TRY_AGAIN)
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return "Host not found (non-authoritative)";
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else if (err == NO_RECOVERY)
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return "Non recoverable errors";
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else if (err == NO_DATA || err == NO_ADDRESS)
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return "Valid name, no data record of requested type";
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else
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return "Unknown DNS problem";
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}
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/*
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* Lookup and return the information for a host name (or IP address)
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*/
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static int
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lookup_dns(int fd)
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{
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const struct hostent *result = NULL;
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int reverse_lookup = 0;
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int retry = 0;
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int i;
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struct in_addr addr;
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char *buf;
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ssize_t len;
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char address_buf[1024];
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len = readline(fd, &buf);
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chomp(buf, len);
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if (strcmp(buf, "$shutdown") == 0)
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return 0;
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if (strcmp(buf, "$hello") == 0) {
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write_message(fd, "$alive\n");
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return 1;
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}
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/*
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* Check to see if the buffer is an IP address in dotted-decimal
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* form.
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*/
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for (;;) {
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if (inet_aton(buf, &addr)) {
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reverse_lookup = 1;
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result = gethostbyaddr((char *)&addr.s_addr, 4, AF_INET);
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} else {
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result = gethostbyname(buf);
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}
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if (NULL != result)
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break;
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if (h_errno != TRY_AGAIN)
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break;
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if (++retry == 3)
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break;
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sleep(1);
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}
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if (NULL == result) {
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if (h_errno == TRY_AGAIN) {
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write_message(fd, "$fail Name Server for domain '%s' is unavailable.\n", buf);
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} else {
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write_message(fd, "$fail DNS Domain '%s' is invalid: %s.\n",
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buf, dns_error_messages(h_errno));
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}
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return 1;
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}
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if (reverse_lookup) {
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write_message(fd, "$name %s\n", result->h_name);
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return 1;
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}
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strlcpy(address_buf, "$addr", sizeof(address_buf));
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for (i = 0; i < 32; i++) {
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if (!result->h_addr_list[i])
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break;
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memcpy(&addr, result->h_addr_list[i], sizeof(addr));
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strlcat(address_buf, " ", sizeof(address_buf));
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strlcat(address_buf, inet_ntoa(addr), sizeof(address_buf));
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}
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write_message(fd, "%s\n", address_buf);
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return 1;
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}
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/*
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* Print out a usage message.
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*/
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static void
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usage(void)
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{
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fprintf(stderr, "usage: dnsserver path\n");
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}
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/*
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* Start up function. Create the sockets and fork() when needed.
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*/
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int
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main(int argc, char **argv)
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{
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int listenfd, connfd;
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pid_t childpid;
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socklen_t clilen;
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struct sockaddr_un cliaddr, servaddr;
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if (--argc != 1) {
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usage();
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exit(1);
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}
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/*
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* The path for the socket is supplied as the one (and only) command
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* line argument.
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*/
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unix_socket_path = safestrdup(argv[1]);
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if (!unix_socket_path) {
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fprintf(stderr, "%s: could not allocate memory.\n", argv[0]);
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exit(1);
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}
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/* Create the listening socket */
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listenfd = socket(AF_LOCAL, SOCK_STREAM, 0);
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if (listenfd < 0) {
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fprintf(stderr, "%s: could not create listening socket.\n",
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argv[0]);
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exit(1);
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}
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memset(&servaddr, 0, sizeof(servaddr));
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servaddr.sun_family = AF_LOCAL;
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strcpy(servaddr.sun_path, unix_socket_path);
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if (bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
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fprintf(stderr, "%s: could not bind socket.\n", argv[0]);
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exit(1);
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}
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if (listen(listenfd, MAXLISTEN) < 0) {
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fprintf(stderr, "%s: could not start listening on socket.\n",
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argv[0]);
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exit(1);
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}
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set_signal_handler(SIGCHLD, child_signal_handler);
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set_signal_handler(SIGTERM, term_signal_handler);
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for ( ; ; ) {
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clilen = sizeof(cliaddr);
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if ((connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &clilen)) < 0) {
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if (errno == EINTR)
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continue;
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else
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exit(1);
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}
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if ((childpid = fork()) == 0) {
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/* child process */
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close(listenfd);
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while (lookup_dns(connfd))
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;
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close(connfd);
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exit(0);
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}
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close(connfd); /* parent closes connected socket */
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}
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}
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