#include <u.h>#include <libc.h>#include <fcall.h>#define Extern#include "exportfs.h" int	srvfd = -1;int	readonly; voidusage(void){	fprint(2, "usage: %s [-dsR] [-m msize] [-r root] "		"[-P patternfile] [-S srvfile]\n", argv0);	fatal("usage");} voidmain(int argc, char **argv){	char *srv, *srvfdfile; 	srv = nil;	srvfd = -1;	srvfdfile = nil; 	ARGBEGIN{	case 'd':		dbg++;		break; 	case 'm':		messagesize = strtoul(EARGF(usage()), nil, 0);		break; 	case 'r':		srv = EARGF(usage());		break; 	case 's':		srv = "/";		break; 	case 'F':		/* accepted but ignored, for backwards compatibility */		break; 	case 'P':		patternfile = EARGF(usage());		break; 	case 'R':		readonly = 1;		break; 	case 'S':		if(srvfdfile != nil)			usage();		srvfdfile = EARGF(usage());		break; 	default:		usage();	}ARGEND	USED(argc, argv); 	if(srvfdfile != nil){		if(srv != nil){			fprint(2, "exportfs: -S cannot be used with -r or -s\n");			usage();		}		if((srvfd = open(srvfdfile, ORDWR)) < 0)			fatal("open %s: %r", srvfdfile);	} else if(srv == nil)		usage(); 	exclusions(); 	DEBUG(2, "exportfs: started\n"); 	rfork(RFNOTEG|RFREND); 	if(messagesize == 0){		messagesize = iounit(0);		if(messagesize == 0)			messagesize = IOUNIT+IOHDRSZ;	}	fhash = emallocz(sizeof(Fid*)*FHASHSIZE); 	fmtinstall('F', fcallfmt); 	if(srvfd == -1) {		if(chdir(srv) < 0) {			char ebuf[ERRMAX];			ebuf[0] = '\0';			errstr(ebuf, sizeof ebuf);			DEBUG(2, "chdir(\"%s\"): %s\n", srv, ebuf);			mounterror(ebuf);		}		DEBUG(2, "invoked as server for %s", srv);	} 	DEBUG(2, "\niniting root\n");	initroot();	io();}