/* -*- c-file-style: "linux" -*-    rsync -- fast file replication program    Copyright (C) 1992-2001 by Andrew Tridgell <tridge@samba.org>   Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>    This program is free software; you can redistribute it and/or modify   it under the terms of the GNU General Public License as published by   the Free Software Foundation; either version 2 of the License, or   (at your option) any later version.    This program is distributed in the hope that it will be useful,   but WITHOUT ANY WARRANTY; without even the implied warranty of   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the   GNU General Public License for more details.    You should have received a copy of the GNU General Public License   along with this program; if not, write to the Free Software   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.*/ /** * @file socket.c * * Socket functions used in rsync. * * This file is now converted to use the new-style getaddrinfo() * interface, which supports IPv6 but is also supported on recent * IPv4-only machines.  On systems that don't have that interface, we * emulate it using the KAME implementation. **/ #include "rsync.h"  /** * Establish a proxy connection on an open socket to a web proxy by * using the CONNECT method. If proxy_user and proxy_pass are not NULL, * they are used to authenticate to the proxy using the "Basic" * proxy-authorization protocol **/static int establish_proxy_connection(int fd, char *host, int port,				      char *proxy_user, char *proxy_pass){	char *cp, buffer[1024];	char *authhdr, authbuf[1024];	int len; 	if (proxy_user && proxy_pass) {		stringjoin(buffer, sizeof buffer,			 proxy_user, ":", proxy_pass, NULL);		len = strlen(buffer); 		if ((len*8 + 5) / 6 >= (int)sizeof authbuf) {			rprintf(FERROR,				"authentication information is too long\n");			return -1;		} 		base64_encode(buffer, len, authbuf);		authhdr = "\r\nProxy-Authorization: Basic ";	} else {		*authbuf = '\0';		authhdr = "";	} 	snprintf(buffer, sizeof buffer, "CONNECT %s:%d HTTP/1.0%s%s\r\n\r\n",		 host, port, authhdr, authbuf);	len = strlen(buffer);	if (write(fd, buffer, len) != len) {		rprintf(FERROR, "failed to write to proxy: %s\n",			strerror(errno));		return -1;	} 	for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {		if (read(fd, cp, 1) != 1) {			rprintf(FERROR, "failed to read from proxy: %s\n",				strerror(errno));			return -1;		}		if (*cp == '\n')			break;	} 	if (*cp != '\n')		cp++;	*cp-- = '\0';	if (*cp == '\r')		*cp = '\0';	if (strncmp(buffer, "HTTP/", 5) != 0) {		rprintf(FERROR, "bad response from proxy - %s\n",			buffer);		return -1;	}	for (cp = &buffer[5]; isdigit(*(uchar*)cp) || *cp == '.'; cp++) {}	while (*cp == ' ')		cp++;	if (*cp != '2') {		rprintf(FERROR, "bad response from proxy - %s\n",			buffer);		return -1;	}	/* throw away the rest of the HTTP header */	while (1) {		for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {			if (read(fd, cp, 1) != 1) {				rprintf(FERROR, "failed to read from proxy: %s\n",					strerror(errno));				return -1;			}			if (*cp == '\n')				break;		}		if (cp > buffer && *cp == '\n')			cp--;		if (cp == buffer && (*cp == '\n' || *cp == '\r'))			break;	}	return 0;}  /** * Try to set the local address for a newly-created socket.  Return -1 * if this fails. **/int try_bind_local(int s, int ai_family, int ai_socktype,		   const char *bind_address){	int error;	struct addrinfo bhints, *bres_all, *r; 	memset(&bhints, 0, sizeof bhints);	bhints.ai_family = ai_family;	bhints.ai_socktype = ai_socktype;	bhints.ai_flags = AI_PASSIVE;	if ((error = getaddrinfo(bind_address, NULL, &bhints, &bres_all))) {		rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n",			bind_address, gai_strerror(error));		return -1;	} 	for (r = bres_all; r; r = r->ai_next) {		if (bind(s, r->ai_addr, r->ai_addrlen) == -1)			continue;		freeaddrinfo(bres_all);		return s;	} 	/* no error message; there might be some problem that allows	 * creation of the socket but not binding, perhaps if the	 * machine has no ipv6 address of this name. */	freeaddrinfo(bres_all);	return -1;}  /** * Open a socket to a tcp remote host with the specified port . * * Based on code from Warren.  Proxy support by Stephen Rothwell. * getaddrinfo() rewrite contributed by KAME.net. * * Now that we support IPv6 we need to look up the remote machine's * address first, using @p af_hint to set a preference for the type * of address.  Then depending on whether it has v4 or v6 addresses we * try to open a connection. * * The loop allows for machines with some addresses which may not be * reachable, perhaps because we can't e.g. route ipv6 to that network * but we can get ip4 packets through. * * @param bind_address Local address to use.  Normally NULL to bind * the wildcard address. * * @param af_hint Address family, e.g. AF_INET or AF_INET6. **/int open_socket_out(char *host, int port, const char *bind_address,		    int af_hint){	int type = SOCK_STREAM;	int error, s;	struct addrinfo hints, *res0, *res;	char portbuf[10];	char *h, *cp;	int proxied = 0;	char buffer[1024];	char *proxy_user = NULL, *proxy_pass = NULL; 	/* if we have a RSYNC_PROXY env variable then redirect our	 * connetcion via a web proxy at the given address. */	h = getenv("RSYNC_PROXY");	proxied = h != NULL && *h != '\0'; 	if (proxied) {		strlcpy(buffer, h, sizeof buffer); 		/* Is the USER:PASS@ prefix present? */		if ((cp = strchr(buffer, '@')) != NULL) {			*cp++ = '\0';			/* The remainder is the HOST:PORT part. */			h = cp; 			if ((cp = strchr(buffer, ':')) == NULL) {				rprintf(FERROR,					"invalid proxy specification: should be USER:PASS@HOST:PORT\n");				return -1;			}			*cp++ = '\0'; 			proxy_user = buffer;			proxy_pass = cp;		} else {			/* The whole buffer is the HOST:PORT part. */			h = buffer;		} 		if ((cp = strchr(h, ':')) == NULL) {			rprintf(FERROR,				"invalid proxy specification: should be HOST:PORT\n");			return -1;		}		*cp++ = '\0';		strlcpy(portbuf, cp, sizeof portbuf);		if (verbose >= 2) {			rprintf(FINFO, "connection via http proxy %s port %s\n",				h, portbuf);		}	} else {		snprintf(portbuf, sizeof portbuf, "%d", port);		h = host;	} 	memset(&hints, 0, sizeof hints);	hints.ai_family = af_hint;	hints.ai_socktype = type;	error = getaddrinfo(h, portbuf, &hints, &res0);	if (error) {		rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",			h, portbuf, gai_strerror(error));		return -1;	} 	s = -1;	/* Try to connect to all addresses for this machine until we get	 * through.  It might e.g. be multi-homed, or have both IPv4 and IPv6	 * addresses.  We need to create a socket for each record, since the	 * address record tells us what protocol to use to try to connect. */	for (res = res0; res; res = res->ai_next) {		s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);		if (s < 0)			continue; 		if (bind_address		 && try_bind_local(s, res->ai_family, type,				   bind_address) == -1) {			close(s);			s = -1;			continue;		}		if (connect(s, res->ai_addr, res->ai_addrlen) < 0) {			close(s);			s = -1;			continue;		}		if (proxied		 && establish_proxy_connection(s, host, port,					       proxy_user, proxy_pass) != 0) {			close(s);			s = -1;			continue;		}		break;	}	freeaddrinfo(res0);	if (s < 0) {		rprintf(FERROR, RSYNC_NAME ": failed to connect to %s: %s\n",			h, strerror(errno));		return -1;	}	return s;}  /** * Open an outgoing socket, but allow for it to be intercepted by * $RSYNC_CONNECT_PROG, which will execute a program across a TCP * socketpair rather than really opening a socket. * * We use this primarily in testing to detect TCP flow bugs, but not * cause security problems by really opening remote connections. * * This is based on the Samba LIBSMB_PROG feature. * * @param bind_address Local address to use.  Normally NULL to get the stack default. **/int open_socket_out_wrapped(char *host, int port, const char *bind_address,			    int af_hint){	char *prog = getenv("RSYNC_CONNECT_PROG"); 	if (verbose >= 2) {		rprintf(FINFO, "%sopening tcp connection to %s port %d\n",			prog ? "Using RSYNC_CONNECT_PROG instead of " : "",			host, port);	}	if (prog)		return sock_exec(prog);	return open_socket_out(host, port, bind_address, af_hint);}   /** * Open a socket of the specified type, port and address for incoming data * * Try to be better about handling the results of getaddrinfo(): when * opening an inbound socket, we might get several address results, * e.g. for the machine's ipv4 and ipv6 name. * * If binding a wildcard, then any one of them should do.  If an address * was specified but it's insufficiently specific then that's not our * fault. * * However, some of the advertized addresses may not work because e.g. we * don't have IPv6 support in the kernel.  In that case go on and try all * addresses until one succeeds. * * @param bind_address Local address to bind, or NULL to allow it to * default. **/static int *open_socket_in(int type, int port, const char *bind_address,			   int af_hint){	int one=1;	int s, *sp, *socks, maxs;	struct addrinfo hints, *all_ai, *resp;	char portbuf[10];	int error; 	memset(&hints, 0, sizeof hints);	hints.ai_family = af_hint;	hints.ai_socktype = type;	hints.ai_flags = AI_PASSIVE;	snprintf(portbuf, sizeof portbuf, "%d", port);	error = getaddrinfo(bind_address, portbuf, &hints, &all_ai);	if (error) {		rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",			bind_address, gai_strerror(error));		return NULL;	} 	/* Count max number of sockets we might open. */	for (maxs = 0, resp = all_ai; resp; resp = resp->ai_next, maxs++) {}	socks = new_array(int, maxs + 1);	if (!socks) {		rprintf(FERROR,			RSYNC_NAME "couldn't allocate memory for sockets");		return NULL;	} 	/* We may not be able to create the socket, if for example the	 * machine knows about IPv6 in the C library, but not in the	 * kernel. */	sp = socks + 1; /* Leave room for count at start of array. */	for (resp = all_ai; resp; resp = resp->ai_next) {		s = socket(resp->ai_family, resp->ai_socktype,			   resp->ai_protocol); 		if (s == -1) {			/* See if there's another address that will work... */			continue;		} 		setsockopt(s, SOL_SOCKET, SO_REUSEADDR,			   (char *)&one, sizeof one); #ifdef IPV6_V6ONLY		if (resp->ai_family == AF_INET6) {			setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,				   (char *)&one, sizeof one);		}#endif 		/* Now we've got a socket - we need to bind it. */		if (bind(s, resp->ai_addr, resp->ai_addrlen) < 0) {			/* Nope, try another */			close(s);			continue;		} 		*sp++ = s;	}	*socks = sp - socks - 1;   /* Save count. */ 	if (all_ai)		freeaddrinfo(all_ai); 	if (*socks == 0) {		rprintf(FERROR,			RSYNC_NAME ": open inbound socket on port %d failed: "			"%s\n", port, strerror(errno));		free(socks);		return NULL;	}	return socks;}  /* * Determine if a file descriptor is in fact a socket */int is_a_socket(int fd){	int v;	socklen_t l = sizeof (int); 	/* Parameters to getsockopt, setsockopt etc are very	 * unstandardized across platforms, so don't be surprised if	 * there are compiler warnings on e.g. SCO OpenSwerver or AIX.	 * It seems they all eventually get the right idea.	 *	 * Debian says: ``The fifth argument of getsockopt and	 * setsockopt is in reality an int [*] (and this is what BSD	 * 4.* and libc4 and libc5 have).  Some POSIX confusion	 * resulted in the present socklen_t.  The draft standard has	 * not been adopted yet, but glibc2 already follows it and	 * also has socklen_t [*]. See also accept(2).''	 *	 * We now return to your regularly scheduled programming.  */	return getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0;}  static RETSIGTYPE sigchld_handler(UNUSED(int val)){#ifdef WNOHANG	while (waitpid(-1, NULL, WNOHANG) > 0) {}#endif	signal(SIGCHLD, sigchld_handler);}  void start_accept_loop(int port, int (*fn)(int, int)){	fd_set deffds;	int *sp, maxfd, i, j;	extern char *bind_address;	extern int default_af_hint; 	/* open an incoming socket */	sp = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint);	if (sp == NULL)		exit_cleanup(RERR_SOCKETIO); 	/* ready to listen */	FD_ZERO(&deffds);	maxfd = -1;	for (i = 1; i <= *sp; i++) {		if (listen(sp[i], 5) == -1) {			for (j = 1; j <= i; j++)				close(sp[j]);			free(sp);			exit_cleanup(RERR_SOCKETIO);		}		FD_SET(sp[i], &deffds);		if (maxfd < sp[i])			maxfd = sp[i];	}  	/* now accept incoming connections - forking a new process	 * for each incoming connection */	while (1) {		fd_set fds;		pid_t pid;		int fd;		struct sockaddr_storage addr;		socklen_t addrlen = sizeof addr; 		/* close log file before the potentially very long select so		 * file can be trimmed by another process instead of growing		 * forever */		log_close(); #ifdef FD_COPY		FD_COPY(&deffds, &fds);#else		fds = deffds;#endif 		if (select(maxfd + 1, &fds, NULL, NULL, NULL) != 1)			continue; 		fd = -1;		for (i = 1; i <= *sp; i++) {			if (FD_ISSET(sp[i], &fds)) {				fd = accept(sp[i], (struct sockaddr *)&addr,

Lines 1–500 of 789. Load more