/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <bio.h>#include <ctype.h>#include <ndb.h>#include "dns.h"#include "ip.h" static int domount;static char *mtpt, *dns, *srv; static intsetup(int argc, char **argv){	int fd; 	if(argc == 1){		domount = 0;		mtpt = argv[0];	} 	fd = open(dns, ORDWR);	if(fd < 0){		if(domount == 0)			sysfatal("can't open %s: %r", dns);		fd = open(srv, ORDWR);		if(fd < 0)			sysfatal("can't open %s: %r", srv);		if(mount(fd, -1, mtpt, MBEFORE, "") < 0)			sysfatal("can't mount(%s, %s): %r", srv, mtpt);		fd = open(dns, ORDWR);		if(fd < 0)			sysfatal("can't open %s: %r", dns);	}	return fd;} static voidquerydns(int fd, char *line, int n){	char buf[1024]; 	seek(fd, 0, 0);	if(write(fd, line, n) != n) {		print("!%r\n");		return;	}	seek(fd, 0, 0);	buf[0] = '\0';	while((n = read(fd, buf, sizeof(buf))) > 0){		buf[n] = '\0';		print("%s\n", buf);	}} static voidquery(int fd){	int n, len;	char *lp, *p, *np;	char buf[1024], line[1024];	Biobuf in; 	Binit(&in, 0, OREAD);	for(print("> "); lp = Brdline(&in, '\n'); print("> ")){		n = Blinelen(&in) -1;		while(isspace(lp[n]))			lp[n--] = 0;		n++;		while(isspace(*lp)){			lp++;			n--;		}		if(!*lp)			continue;		strcpy(line, lp); 		/* default to an "ip" request if alpha, "ptr" if numeric */		if(strchr(line, ' ') == nil)			if(strcmp(ipattr(line), "ip") == 0) {				strcat(line, " ptr");				n += 4;			} else {				strcat(line, " ip");				n += 3;			} 		/* inverse queries may need to be permuted */		if(n > 4 && strcmp(" ptr", &line[n-4]) == 0 &&		    cistrstr(line, ".arpa") == nil){			/* TODO: reversing v6 addrs is harder */			for(p = line; *p; p++)				if(*p == ' '){					*p = '.';					break;				}			np = buf;			len = 0;			while(p >= line){				len++;				p--;				if(*p == '.'){					memmove(np, p+1, len);					np += len;					len = 0;				}			}			memmove(np, p+1, len);			np += len;			strcpy(np, "in-addr.arpa ptr");	/* TODO: ip6.arpa for v6 */			strcpy(line, buf);			n = strlen(line);		} 		querydns(fd, line, n);	}	Bterm(&in);} voidmain(int argc, char *argv[]){	mtpt = "/net";	dns = "/net/dns";	srv = "/srv/dns";	domount = 1;	ARGBEGIN {	case 'x':		mtpt = "/net.alt";		dns = "/net.alt/dns";		srv = "/srv/dns_net.alt";		break;	default:		fprint(2, "usage: %s [-x] [dns-mount-point]\n", argv0);		exits("usage");	} ARGEND; 	query(setup(argc, argv));	exits(0);}