add dns

src/cmd/ndb/dnsquery.c

@@ -0,0 +1,113 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <ndb.h>
+#include "dns.h"
+#include "ip.h"
+
+void
+main(int argc, char *argv[])
+{
+	int fd, n, len, domount;
+	Biobuf in;
+	char line[1024], *lp, *p, *np, *mtpt, *srv, *dns;
+	char buf[1024];
+
+	dns = "/net/dns";
+	mtpt = "/net";
+	srv = "/srv/dns";
+	domount = 1;
+	ARGBEGIN {
+	case 'x':
+		dns = "/net.alt/dns";
+		mtpt = "/net.alt";
+		srv = "/srv/dns_net.alt";
+		break;
+	default:
+		fprint(2, "usage: %s -x [dns-mount-point]\n", argv0);
+		exits("usage");
+	} ARGEND;
+
+	if(argc == 1){
+		domount = 0;
+		mtpt = argv[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(mtpt, ORDWR);
+		if(fd < 0){
+			print("can't open %s: %r\n", mtpt);
+			exits(0);
+		}
+	}
+	Binit(&in, 0, OREAD);
+	for(print("> "); lp = Brdline(&in, '\n'); print("> ")){
+		n = Blinelen(&in)-1;
+		strncpy(line, lp, n);
+		line[n] = 0;
+		if (n<=1)
+			continue;
+		/* default to an "ip" request if alpha, "ptr" if numeric */
+		if (strchr(line, ' ')==0) {
+			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-3]) == 0
+		&& strstr(line, "IN-ADDR") == 0 && strstr(line, "in-addr") == 0){
+			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");
+			strcpy(line, buf);
+			n = strlen(line);
+		}
+
+		seek(fd, 0, 0);
+		if(write(fd, line, n) < 0) {
+			print("!%r\n");
+			continue;
+		}
+		seek(fd, 0, 0);
+		while((n = read(fd, buf, sizeof(buf))) > 0){
+			buf[n] = 0;
+			print("%s\n", buf);
+		}
+	}
+	exits(0);
+}