server.c

来自「samba-3.0.22.tar.gz 编译smb服务器的源码」· C语言 代码 · 共 983 行 · 第 1/2 页

/* 
   Unix SMB/CIFS implementation.
   Main SMB server routines
   Copyright (C) Andrew Tridgell		1992-1998
   Copyright (C) Martin Pool			2002
   Copyright (C) Jelmer Vernooij		2002-2003
   
   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.
*/

#include "includes.h"

#ifdef HAVE_SYS_PRCTL_H
#include <sys/prctl.h>
#endif

static int am_parent = 1;

/* the last message the was processed */
int last_message = -1;

/* a useful macro to debug the last message processed */
#define LAST_MESSAGE() smb_fn_name(last_message)

extern struct auth_context *negprot_global_auth_context;
extern pstring user_socket_options;
extern SIG_ATOMIC_T got_sig_term;
extern SIG_ATOMIC_T reload_after_sighup;

#ifdef WITH_DFS
extern int dcelogin_atmost_once;
#endif /* WITH_DFS */

/* really we should have a top level context structure that has the
   client file descriptor as an element. That would require a major rewrite :(

   the following 2 functions are an alternative - they make the file
   descriptor private to smbd
 */
static int server_fd = -1;

int smbd_server_fd(void)
{
	return server_fd;
}

static void smbd_set_server_fd(int fd)
{
	server_fd = fd;
	client_setfd(fd);
}

/****************************************************************************
 Terminate signal.
****************************************************************************/

static void sig_term(void)
{
	got_sig_term = 1;
	sys_select_signal(SIGTERM);
}

/****************************************************************************
 Catch a sighup.
****************************************************************************/

static void sig_hup(int sig)
{
	reload_after_sighup = 1;
	sys_select_signal(SIGHUP);
}

/****************************************************************************
  Send a SIGTERM to our process group.
*****************************************************************************/

static void  killkids(void)
{
	if(am_parent) kill(0,SIGTERM);
}

/****************************************************************************
 Process a sam sync message - not sure whether to do this here or
 somewhere else.
****************************************************************************/

static void msg_sam_sync(int UNUSED(msg_type), struct process_id UNUSED(pid),
			 void *UNUSED(buf), size_t UNUSED(len))
{
        DEBUG(10, ("** sam sync message received, ignoring\n"));
}

/****************************************************************************
 Process a sam sync replicate message - not sure whether to do this here or
 somewhere else.
****************************************************************************/

static void msg_sam_repl(int msg_type, struct process_id pid,
			 void *buf, size_t len)
{
        uint32 low_serial;

        if (len != sizeof(uint32))
                return;

        low_serial = *((uint32 *)buf);

        DEBUG(3, ("received sam replication message, serial = 0x%04x\n",
                  low_serial));
}

/****************************************************************************
 Open the socket communication - inetd.
****************************************************************************/

static BOOL open_sockets_inetd(void)
{
	/* Started from inetd. fd 0 is the socket. */
	/* We will abort gracefully when the client or remote system 
	   goes away */
	smbd_set_server_fd(dup(0));
	
	/* close our standard file descriptors */
	close_low_fds(False); /* Don't close stderr */
	
	set_socket_options(smbd_server_fd(),"SO_KEEPALIVE");
	set_socket_options(smbd_server_fd(), user_socket_options);

	return True;
}

static void msg_exit_server(int msg_type, struct process_id src,
			    void *buf, size_t len)
{
	exit_server("Got a SHUTDOWN message");
}


/****************************************************************************
 Have we reached the process limit ?
****************************************************************************/

static BOOL allowable_number_of_smbd_processes(void)
{
	int max_processes = lp_max_smbd_processes();

	if (!max_processes)
		return True;

	{
		TDB_CONTEXT *tdb = conn_tdb_ctx();
		int32 val;
		if (!tdb) {
			DEBUG(0,("allowable_number_of_smbd_processes: can't open connection tdb.\n" ));
			return False;
		}

		val = tdb_fetch_int32(tdb, "INFO/total_smbds");
		if (val == -1 && (tdb_error(tdb) != TDB_ERR_NOEXIST)) {
			DEBUG(0,("allowable_number_of_smbd_processes: can't fetch INFO/total_smbds. Error %s\n",
				tdb_errorstr(tdb) ));
			return False;
		}
		if (val > max_processes) {
			DEBUG(0,("allowable_number_of_smbd_processes: number of processes (%d) is over allowed limit (%d)\n",
				val, max_processes ));
			return False;
		}
	}
	return True;
}

/****************************************************************************
 Open the socket communication.
****************************************************************************/

static BOOL open_sockets_smbd(BOOL is_daemon, BOOL interactive, const char *smb_ports)
{
	int num_interfaces = iface_count();
	int num_sockets = 0;
	int fd_listenset[FD_SETSIZE];
	fd_set listen_set;
	int s;
	int maxfd = 0;
	int i;
	char *ports;

	if (!is_daemon) {
		return open_sockets_inetd();
	}

		
#ifdef HAVE_ATEXIT
	{
		static int atexit_set;
		if(atexit_set == 0) {
			atexit_set=1;
			atexit(killkids);
		}
	}
#endif

	/* Stop zombies */
	CatchChild();
				
	FD_ZERO(&listen_set);

	/* use a reasonable default set of ports - listing on 445 and 139 */
	if (!smb_ports) {
		ports = lp_smb_ports();
		if (!ports || !*ports) {
			ports = smb_xstrdup(SMB_PORTS);
		} else {
			ports = smb_xstrdup(ports);
		}
	} else {
		ports = smb_xstrdup(smb_ports);
	}

	if (lp_interfaces() && lp_bind_interfaces_only()) {
		/* We have been given an interfaces line, and been 
		   told to only bind to those interfaces. Create a
		   socket per interface and bind to only these.
		*/
		
		/* Now open a listen socket for each of the
		   interfaces. */
		for(i = 0; i < num_interfaces; i++) {
			struct in_addr *ifip = iface_n_ip(i);
			fstring tok;
			const char *ptr;

			if(ifip == NULL) {
				DEBUG(0,("open_sockets_smbd: interface %d has NULL IP address !\n", i));
				continue;
			}

			for (ptr=ports; next_token(&ptr, tok, " \t,", sizeof(tok)); ) {
				unsigned port = atoi(tok);
				if (port == 0) {
					continue;
				}
				s = fd_listenset[num_sockets] = open_socket_in(SOCK_STREAM, port, 0, ifip->s_addr, True);
				if(s == -1)
					return False;

				/* ready to listen */
				set_socket_options(s,"SO_KEEPALIVE"); 
				set_socket_options(s,user_socket_options);
     
				/* Set server socket to non-blocking for the accept. */
				set_blocking(s,False); 
 
				if (listen(s, SMBD_LISTEN_BACKLOG) == -1) {
					DEBUG(0,("listen: %s\n",strerror(errno)));
					close(s);
					return False;
				}
				FD_SET(s,&listen_set);
				maxfd = MAX( maxfd, s);

				num_sockets++;
				if (num_sockets >= FD_SETSIZE) {
					DEBUG(0,("open_sockets_smbd: Too many sockets to bind to\n"));
					return False;
				}
			}
		}
	} else {
		/* Just bind to 0.0.0.0 - accept connections
		   from anywhere. */

		fstring tok;
		const char *ptr;

		num_interfaces = 1;
		
		for (ptr=ports; next_token(&ptr, tok, " \t,", sizeof(tok)); ) {
			unsigned port = atoi(tok);
			if (port == 0) continue;
			/* open an incoming socket */
			s = open_socket_in(SOCK_STREAM, port, 0,
					   interpret_addr(lp_socket_address()),True);
			if (s == -1)
				return(False);
		
			/* ready to listen */
			set_socket_options(s,"SO_KEEPALIVE"); 
			set_socket_options(s,user_socket_options);
			
			/* Set server socket to non-blocking for the accept. */
			set_blocking(s,False); 
 
			if (listen(s, SMBD_LISTEN_BACKLOG) == -1) {
				DEBUG(0,("open_sockets_smbd: listen: %s\n",
					 strerror(errno)));
				close(s);
				return False;
			}

			fd_listenset[num_sockets] = s;
			FD_SET(s,&listen_set);
			maxfd = MAX( maxfd, s);

			num_sockets++;

			if (num_sockets >= FD_SETSIZE) {
				DEBUG(0,("open_sockets_smbd: Too many sockets to bind to\n"));
				return False;
			}
		}
	} 

	SAFE_FREE(ports);

        /* Listen to messages */

        message_register(MSG_SMB_SAM_SYNC, msg_sam_sync);
        message_register(MSG_SMB_SAM_REPL, msg_sam_repl);
        message_register(MSG_SHUTDOWN, msg_exit_server);

	/* now accept incoming connections - forking a new process
	   for each incoming connection */
	DEBUG(2,("waiting for a connection\n"));
	while (1) {
		fd_set lfds;
		int num;
		
		/* Free up temporary memory from the main smbd. */
		lp_talloc_free();

		/* Ensure we respond to PING and DEBUG messages from the main smbd. */
		message_dispatch();

		memcpy((char *)&lfds, (char *)&listen_set, 
		       sizeof(listen_set));
		
		num = sys_select(maxfd+1,&lfds,NULL,NULL,NULL);
		
		if (num == -1 && errno == EINTR) {
			if (got_sig_term) {
				exit_server("Caught TERM signal");
			}

			/* check for sighup processing */
			if (reload_after_sighup) {
				change_to_root_user();
				DEBUG(1,("Reloading services after SIGHUP\n"));
				reload_services(False);
				reload_after_sighup = 0;
			}

			continue;
		}
		
		/* check if we need to reload services */
		check_reload(time(NULL));

		/* Find the sockets that are read-ready -
		   accept on these. */
		for( ; num > 0; num--) {
			struct sockaddr addr;
			socklen_t in_addrlen = sizeof(addr);

			s = -1;
			for(i = 0; i < num_sockets; i++) {
				if(FD_ISSET(fd_listenset[i],&lfds)) {
					s = fd_listenset[i];
					/* Clear this so we don't look
					   at it again. */
					FD_CLR(fd_listenset[i],&lfds);
					break;
				}
			}

			smbd_set_server_fd(accept(s,&addr,&in_addrlen));
			
			if (smbd_server_fd() == -1 && errno == EINTR)
				continue;
			
			if (smbd_server_fd() == -1) {
				DEBUG(0,("open_sockets_smbd: accept: %s\n",
					 strerror(errno)));
				continue;
			}

			/* Ensure child is set to blocking mode */
			set_blocking(smbd_server_fd(),True);

			if (smbd_server_fd() != -1 && interactive)
				return True;
			
			if (allowable_number_of_smbd_processes() && smbd_server_fd() != -1 && sys_fork()==0) {
				/* Child code ... */
				
				/* close the listening socket(s) */
				for(i = 0; i < num_sockets; i++)
					close(fd_listenset[i]);
				
				/* close our standard file
				   descriptors */
				close_low_fds(False);
				am_parent = 0;
				
				set_socket_options(smbd_server_fd(),"SO_KEEPALIVE");
				set_socket_options(smbd_server_fd(),user_socket_options);
				
				/* this is needed so that we get decent entries
				   in smbstatus for port 445 connects */
				set_remote_machine_name(get_peer_addr(smbd_server_fd()), False);
				
				/* Reset the state of the random
				 * number generation system, so
				 * children do not get the same random
				 * numbers as each other */

				set_need_random_reseed();
				/* tdb needs special fork handling - remove CLEAR_IF_FIRST flags */
				if (tdb_reopen_all() == -1) {
					DEBUG(0,("tdb_reopen_all failed.\n"));
					smb_panic("tdb_reopen_all failed.");
				}

				return True; 
			}
			/* The parent doesn't need this socket */
			close(smbd_server_fd()); 

			/* Sun May 6 18:56:14 2001 [e-mail]:
				Clear the closed fd info out of server_fd --
				and more importantly, out of client_fd in
				util_sock.c, to avoid a possible
				getpeername failure if we reopen the logs
				and use %I in the filename.
			*/

			smbd_set_server_fd(-1);

			/* Force parent to check log size after
			 * spawning child.  Fix from
			 * [e-mail].  The
			 * parent smbd will log to logserver.smb.  It
			 * writes only two messages for each child
			 * started/finished. But each child writes,
			 * say, 50 messages also in logserver.smb,
			 * begining with the debug_count of the
			 * parent, before the child opens its own log
			 * file logserver.client. In a worst case
			 * scenario the size of logserver.smb would be
			 * checked after about 50*50=2500 messages
			 * (ca. 100kb).
			 * */
			force_check_log_size();
 
		} /* end for num */
	} /* end while 1 */

/* NOTREACHED	return True; */
}

/****************************************************************************
 Reload printers
**************************************************************************/
void reload_printers(void)
{
	int snum;
	int n_services = lp_numservices();
	int pnum = lp_servicenumber(PRINTERS_NAME);
	const char *pname;

	pcap_cache_reload();

	/* remove stale printers */
	for (snum = 0; snum < n_services; snum++) {
		/* avoid removing PRINTERS_NAME or non-autoloaded printers */
		if (snum == pnum || !(lp_snum_ok(snum) && lp_print_ok(snum) &&
		                      lp_autoloaded(snum)))
			continue;

		pname = lp_printername(snum);