main.c

网络数据管理协议的开发

/*                               -*- Mode: C -*- 
 * main.c
 * 
 * Description     : NDMP daemon main().
 *
 *                   usage: ndmpd [-d debug-level] [-p port-number] [-f]
 *
 *                   where:
 *                     debug-level - The least significant 4 bits of the
 *                                   level specify the detail. 0 will
 *                                   result in mimimal messages for enabled
 *                                   components being output. 15 will
 *                                   result in all messages for enabled
 *                                   components being output.
 *                                   The remaining bits in the level specify
 *                                   the components for which messages are
 *                                   to be output. Refer to ../common/log.h
 *                                   for defined components.
 *                                   Default is all messages disabled.
 *
 *                     port-number - TCP port number on which the NDMP server
 *                                   is listening for connection requests.
 *                                   Default is to lookup the port in the
 *                                   services database.
 *                   
 *                     -f - Disables forking to handle a new connection.
 *                          Default is to fork a child process to handle
 *                          each connection.
 * 
 * Copyright (c) 1996,1997 PDC, Network Appliance. All Rights Reserved.
 *
 * $Id: main.c,v 1.9 1998/05/26 03:52:18 tim Exp $
 */

#if !defined(lint) && !defined(SABER)
static char rcsId[] __attribute__ ((unused)) = "@(#) $Id: main.c,v 1.9 1998/05/26 03:52:18 tim Exp $";
#endif

#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <rpc/rpc.h>

#include "ndmpd.h"

extern NdmpMsgHandler		ndmpdMsgHandlerTable[];

static NdmpConHandlerFunc	connectionHandler;
static NdmpdFileHandlerFunc	connectionFileHandler;

int
main(int	argc,
	 char*	argv[])
{
	int					port = 0;
	bool_t				doFork = TRUE;
	char				c;
	
	pid_t				childPid;
	int					fd;

	extern char			*optarg;
	extern int			optind;
	extern int			opterr;
	
	openlog("ndmpd", LOG_PID|LOG_CONS|LOG_NOWAIT, LOG_DAEMON);
	
	opterr = 0;
	
	while ((c = getopt(argc, argv, "d:fp:")) != -1)
	{
		switch(c)
		{
			case 'd':
			{
				SetDebugLevel(strtol(optarg, 0, 0));
				break;
			}
			
			case 'f':
			{
				doFork = FALSE;
				break;
			}
			
			case 'p':
			{
				port = strtol(optarg, 0, 0);
				break;
			}
			
			default:
			{
				fprintf(stderr, "usage: %s [-d debug-level] [-p port]\n",
						argv[0]);
				exit(1);
			}
		}
	}
	
	/* Ignore terminal stop signals. */
	sigignore(SIGTTOU);
	sigignore(SIGTTIN);
	sigignore(SIGTSTP);

	/*
	 * Only act as a real daemon if not in debug mode.
	 */
	if (doFork == TRUE)
	{
		/*
		 * Fork and let the parent exit in case we weren't started
		 * in the background.
		 * This also guarantees the child is not the process group leader.
		 */
		if ((childPid = fork()) < 0)
		{
			Error(LOG_ERR, "fork error: %s\n", strerror(errno));
			exit(1);
		}
		else if (childPid > 0)
			exit(0);
	
		/*
		 * Disassociate from controlling terminal and process group.
		 * Ensure the process can't reacquire a new controlling terminal.
		 */
		(void)setpgrp();
		sigignore(SIGHUP); /* make self immune from pgrp leader death */

		if ((childPid = fork()) < 0)
		{
			Error(LOG_ERR, "fork error: %s\n", strerror(errno));
			exit(1);
		}
		else if (childPid > 0)
			exit(0);
	}
	
	/*
	 * Close all open file descriptors. 
	 * stderr is left open since it is used for debugging.
	 */
	(void)close(0);
	(void)close(1);
	for (fd = 3; fd < NOFILE; fd++)
		(void)close(fd);
	
	errno = 0;

	(void)chdir("/");	/* Don't want to be on a mounted filesystem */
	(void)umask(0);		/* clear any inherited file mode creation mask */
	
	sigignore(SIGCHLD); /* prevent zombies */
	sigignore(SIGPIPE); /* ignore signals resulting from attempting to
						 * write to a broken pipe. */
	 
	
	ndmpRun(port, doFork, ndmpdMsgHandlerTable, connectionHandler);

	exit(0);
}

/*
 * connectionHandler
 *
 * NDMP connection handler.
 * Waits for, reads, and processes NDMP requests on a connection.
 *
 * Parameters:
 *   connection (input) - connection handle.
 *
 * Return:
 *   void
 */
static void
connectionHandler(NdmpConnection	connection)
{
	static u_long					sessionCounter = 1;

	NdmpdSession					session;
	ndmp_notify_connected_request	req;
	
	Debug(DBG_CAT_CONN|DBG_FOC_FLOW,
		  "ndmpConnectionHandler: received connection.\n");
	
	session.connection                 = connection;
	session.eof                        = FALSE;
	session.protocolVersion            = NDMPVER;
	session.scsi.fd                    = -1;
	session.tape.fd                    = -1;
	session.fileHandlerList            = 0;
	session.id                         = sessionCounter++;
	
	ndmpdDataInit(&session);
	ndmpdFileHistoryInit(&session);
	ndmpdMoverInit(&session);
	
	/*
	 * Setup defaults here. The init functions can not set defaults
	 * since the init functions are called by the stop request handlers
	 * and client set variables need to persist across data operations.
	 */
	session.mover.recordSize           = MAX_RECORD_SIZE;

	ndmpSetClientData(connection, (void *)&session);
	
	req.reason            = NDMP_CONNECTED;
	req.protocol_version  = NDMPVER;
	req.text_reason       = "";
	
	if (ndmpSendRequest(connection, NDMP_NOTIFY_CONNECTED, NDMP_NO_ERR,
						(void*) &req, 0) < 0)
	{
		Debug(DBG_CAT_CONN|DBG_FOC_FLOW,
			  "ndmpConnectionHandler: connection terminated.\n");
		return;
	}
	
	if (ndmpdAddFileHandler(&session, (void*)&session,
							ndmpGetFd(connection),
							NDMPD_SELECT_MODE_READ,
							HC_CLIENT,
							connectionFileHandler) != 0)
		return;
	
	while (session.eof == FALSE)
		ndmpdSelect(&session, TRUE, HC_ALL);
	
	Debug(DBG_CAT_CONN|DBG_FOC_FLOW,
		  "ndmpConnectionHandler: connection terminated.\n");

	(void)ndmpdRemoveFileHandler(&session, ndmpGetFd(connection));

	if (session.scsi.fd != -1)
		(void)close(session.scsi.fd);
	
	if (session.tape.fd != -1)
		(void)close(session.tape.fd);
	
	ndmpdDataCleanup(&session);
	ndmpdFileHistoryCleanup(&session, FALSE);
	ndmpdMoverCleanup(&session);
	
	return;
}


/*
 * connectionFileHandler
 *   Connection file handler function.
 *   Called by ndmpdSelect when data is available to be read on the 
 *   NDMP connection.
 *
 * Parameters:
 *   cookie (input) - session pointer.
 *   fd      (input) - connection file descriptor.
 *   mode    (input) - select mode.
 *
 * Returns:
 *   void.
 */
static void
connectionFileHandler(void*		cookie,
					  int 		fd __attribute__ ((unused)),
					  u_long	mode __attribute__ ((unused)))
{
	NdmpdSession*	session = (NdmpdSession*)cookie;
	
	if (ndmpProcessRequests(session->connection) < 0)
		session->eof = TRUE;
}