ndb/dns: handle txt rr strings as binary, remove nullrr ndb code

txt and caa rr strings might contain binary control characters
such as newlines and double quotes which mess up the output
in ndb(6) format.
so handle them as binary blobs internally and escape special
characters as \DDD where D is a octal digit when printing.

txtrr() will unescape them when reading into internal
binary representation.

remove the undocumented nullrr ndb attribute parsing code.

1 files changed, 58 insertions, 70 deletions

diff --git a/sys/src/cmd/ndb/dn.c b/sys/src/cmd/ndb/dn.c
index 4c3c7f352..377fdd987 100644
--- a/sys/src/cmd/ndb/dn.c
+++ b/sys/src/cmd/ndb/dn.c
@@ -139,7 +139,6 @@ Lock	dnlock;
 static ulong agefreq = Defagefreq;
 
 static int rrequiv(RR *r1, RR *r2);
-static int sencodefmt(Fmt*);
 
 static void
 ding(void*, char *msg)
@@ -157,9 +156,10 @@ dninit(void)
 	fmtinstall('E', eipfmt);
 	fmtinstall('I', eipfmt);
 	fmtinstall('V', eipfmt);
+	fmtinstall('\\', bslashfmt);
 	fmtinstall('R', rrfmt);
 	fmtinstall('Q', rravfmt);
-	fmtinstall('H', sencodefmt);
+	fmtinstall('H', encodefmt);
 
 	dnvars.oldest = maxage;
 	dnvars.names = 0;
@@ -944,7 +944,9 @@ rrcopy(RR *rp, RR **last)
 		*l = nil;
 		for(t = rp->txt; t != nil; t = t->next){
 			nt = emalloc(sizeof(*nt));
-			nt->p = estrdup(t->p);
+			nt->dlen = t->dlen;
+			nt->data = emalloc(t->dlen);
+			memmove(nt->data, t->data, t->dlen);
 			nt->next = nil;
 			*l = nt;
 			l = &nt->next;
@@ -1195,6 +1197,47 @@ idnname(DN *dn, char *buf, int nbuf)
 }
 
 /*
+ *  txt rr strings can contain binary data such as
+ *  control characters and double quotes (") which would
+ *  collide with ndb(6) format.
+ *  escape special characters by encoding them as: \DDD
+ *  where D is a octal digit. backslash (\) is escaped
+ *  by doubling. valid utf8 is encoded verbatim.
+ */
+int
+bslashfmt(Fmt *f)
+{
+	int len, out, n, c;
+	uchar *data;
+
+	out = 0;
+	len = f->prec;
+	f->prec = 0;
+	f->flags &= ~FmtPrec;
+	data = va_arg(f->args, uchar*);
+	for(; len > 0; data += n, len -= n){
+		if(*data >= Runeself && fullrune((char*)data, len)){
+			Rune r;
+
+			n = chartorune(&r, (char*)data);
+			if(r != Runeerror){
+				out += fmtprint(f, "%C", r);
+				continue;
+			}
+		}
+		c = *data;
+		if(c < ' ' || c == '"' || c > '~')
+			out += fmtprint(f, "\\%.3o", c);
+		else if(c == '\\')
+			out += fmtprint(f, "\\\\");
+		else
+			out += fmtprint(f, "%c", c);
+		n = 1;
+	}
+	return out;
+}
+
+/*
  *  print conversion for rr records
  */
 int
@@ -1280,7 +1323,7 @@ rrfmt(Fmt *f)
 	case Ttxt:
 		fmtprint(&fstr, "\t");
 		for(t = rp->txt; t != nil; t = t->next)
-			fmtprint(&fstr, "%s", t->p);
+			fmtprint(&fstr, "%.*\\", t->dlen, t->data);
 		break;
 	case Trp:
 		fmtprint(&fstr, "\t%s %s", dnname(rp->rmb), dnname(rp->rp));
@@ -1314,9 +1357,9 @@ rrfmt(Fmt *f)
 		if (rp->caa == nil)
 			fmtprint(&fstr, "\t<null> <null> <null>");
 		else
-			fmtprint(&fstr, "\t%d %s %.*s",
+			fmtprint(&fstr, "\t%d %s %.*\\",
 				rp->caa->flags, dnname(rp->caa->tag),
-				rp->caa->dlen, (char*)rp->caa->data);
+				rp->caa->dlen, rp->caa->data);
 		break;
 	}
 out:
@@ -1416,7 +1459,7 @@ rravfmt(Fmt *f)
 	case Ttxt:
 		fmtprint(&fstr, " txt=\"");
 		for(t = rp->txt; t != nil; t = t->next)
-			fmtprint(&fstr, "%s", t->p);
+			fmtprint(&fstr, "%.*\\", t->dlen, t->data);
 		fmtprint(&fstr, "\"");
 		break;
 	case Trp:
@@ -1453,9 +1496,9 @@ rravfmt(Fmt *f)
 		if (rp->caa == nil)
 			fmtprint(&fstr, " flags=<null> tag=<null> caa=<null>");
 		else
-			fmtprint(&fstr, " flags=%d tag=%s caa=\"%.*s\"",
+			fmtprint(&fstr, " flags=%d tag=%s caa=\"%.*\\\"",
 				rp->caa->flags, dnname(rp->caa->tag),
-				rp->caa->dlen, (char*)rp->caa->data);
+				rp->caa->dlen, rp->caa->data);
 		break;
 	}
 out:
@@ -1574,14 +1617,14 @@ certequiv(Cert *a, Cert *b)
 static int
 txtequiv(Txt *a, Txt *b)
 {
-	char *ap, *ae, *bp, *be;
+	uchar *ap, *ae, *bp, *be;
 	int n;
 
 	for(ap = ae = bp = be = nil;;ap += n, bp += n){
-		while(a != nil && (ap == nil || (ap == ae && (a = a->next) != nil)))
-			ap = a->p, ae = ap + strlen(ap);
-		while(b != nil && (bp == nil || (bp == be && (b = b->next) != nil)))
-			bp = b->p, be = bp + strlen(bp);
+		while(a != nil && (ap == nil || (ap >= ae && (a = a->next) != nil)))
+			ap = a->data, ae = ap + a->dlen;
+		while(b != nil && (bp == nil || (bp >= be && (b = b->next) != nil)))
+			bp = b->data, be = bp + b->dlen;
 		if(a == b || a == nil || b == nil)
 			break;
 		n = ae - ap;
@@ -1709,61 +1752,6 @@ randomize(RR *rp)
 	return first;
 }
 
-static int
-sencodefmt(Fmt *f)
-{
-	int i, len, ilen, rv;
-	char *out, *buf;
-	uchar *b;
-	char obuf[64];		/* rsc optimization */
-
-	if(!(f->flags&FmtPrec) || f->prec < 1)
-		goto error;
-
-	b = va_arg(f->args, uchar*);
-	if(b == nil)
-		goto error;
-
-	/* if it's a printable, go for it */
-	len = f->prec;
-	for(i = 0; i < len; i++)
-		if(!isprint(b[i]))
-			break;
-	if(i == len){
-		if(len >= sizeof obuf)
-			len = sizeof(obuf)-1;
-		memmove(obuf, b, len);
-		obuf[len] = 0;
-		fmtstrcpy(f, obuf);
-		return 0;
-	}
-
-	ilen = f->prec;
-	f->prec = 0;
-	f->flags &= ~FmtPrec;
-	len = 2*ilen + 1;
-	if(len > sizeof(obuf)){
-		buf = malloc(len);
-		if(buf == nil)
-			goto error;
-	} else
-		buf = obuf;
-
-	/* convert */
-	out = buf;
-	rv = enc16(out, len, b, ilen);
-	if(rv < 0)
-		goto error;
-
-	fmtstrcpy(f, buf);
-	if(buf != obuf)
-		free(buf);
-	return 0;
-
-error:
-	return fmtstrcpy(f, "<encodefmt>");
-}
-
 void*
 emalloc(int size)
 {
@@ -2048,7 +2036,7 @@ rrfree(RR *rp)
 	case Ttxt:
 		while(t = rp->txt){
 			rp->txt = t->next;
-			free(t->p);
+			free(t->data);
 			memset(t, 0, sizeof *t);	/* cause trouble */
 			free(t);
 		}