#include <u.h>#include <libc.h>#include <bio.h>#include <ndb.h>#include "dns.h"#include "ip.h" /* *  convert address into a reverse lookup address */static char*mkptrname(char *p, char *e){	uchar a[IPaddrlen];	int i; 	if(strstr(p, "in-addr.arpa") || strstr(p, "IN-ADDR.ARPA")	|| strstr(p, "ip6.arpa") || strstr(p, "IP6.ARPA")	|| parseip(a, p) == -1)		return p;	if(isv4(a))		p = seprint(p, e, "%ud.%ud.%ud.%ud.in-addr.arpa ptr",			a[15], a[14], a[13], a[12]);	else{		for(i = 15; i >= 0; i--){			p = seprint(p, e, "%ux.", a[i]&0xf);			p = seprint(p, e, "%ux.", a[i]>>4);		}		p = seprint(p, e, "ip6.arpa ptr");	}	*p = 0;	return p;} intdoquery(int fd, char *line, char *p, char *e){	char buf[1024], *type;	int n; 	/* default to an "ip" request if alpha, "ptr" if numeric */		if((type = strchr(line, ' ')) == nil){		type = p+1;		if(strcmp(ipattr(line), "ip") == 0)			p = seprint(p, e, " ptr");		else			p = seprint(p, e, " ip");	}else		type++; 	/* inverse queries may need to be permuted */	if(strcmp(type, "ptr") == 0)		p = mkptrname(line, e); 	seek(fd, 0, 0);	if(write(fd, line, p-line) < 0) {		print("!%r\n");		return -1;	}	seek(fd, 0, 0);	while((n = read(fd, buf, sizeof(buf))) > 0){		buf[n] = 0;		print("%s\n", buf);	}	return 0;} voidmain(int argc, char *argv[]){	int fd, rv, n, domount;	Biobuf in;	char line[1024], *lp, *p, *e, *net, mtpt[40], srv[40], dns[40]; 	net = nil;	domount = 1;	ARGBEGIN {	case 'x':		net = ARGF();		if(net == nil){			/* temporary compatability */			fprint(2, "-x needs argument; assuming net.alt\n");			net = "/net.alt";		}		break;	default:		fprint(2, "usage: %s [-x netmtpt]\n", argv0);		exits("usage");	} ARGEND;	setnetmtpt(mtpt, sizeof mtpt, net);	snprint(dns, sizeof dns, "%s/dns", mtpt);	snprint(srv, sizeof srv, "/srv/dns_%s", mtpt+1);	for(n = strlen(srv); n>0 && srv[-1] == '/'; )		srv[--n] = 0;	if(strcmp(srv, "/srv/dns_net") == 0)		srv[8] = 0; 	fd = open(dns, ORDWR);	if(fd < 0){		if(domount == 0){			fprint(2, "can't open %s: %r\n", mtpt);			exits(0);		}		fd = open(srv, ORDWR);		if(fd < 0){			print("can't open %s: %r\n", srv);			exits(0);		}		if(mount(fd, -1, mtpt, MBEFORE, "") < 0){			print("can't mount(%s, %s): %r\n", srv, mtpt);			exits(0);		}		fd = open(dns, ORDWR);		if(fd < 0){			print("can't open %s: %r\n", mtpt);			exits(0);		}	} 	rv = 0;	if(argc > 0){		p = line;		e = line+sizeof line;		while(--argc)			p = seprint(p, e, "%s ", *argv++);		p = seprint(p, e, "%s", *argv);		*p = 0;		rv |= doquery(fd, line, p, line+sizeof line);	}else{			Binit(&in, 0, OREAD);		for(fprint(2, "> "); lp = Brdline(&in, '\n'); fprint(2, "> ")){			n = Blinelen(&in)-1;			strncpy(line, lp, n);			line[n] = 0;			if (n<=1)				continue;			rv |= doquery(fd, line, line+n, line+sizeof line);		}	}	close(fd);	exits(rv ? "fail" : 0);}