Use isdigit instead of checking character range

When looking for key files, we could use isdigit rather than checking
if the character is within the range [0-9].

Use (unsigned char) cast to ensure the value is representable in the
unsigned char type (as suggested by the isdigit manpage).

Change " & 0xff" occurrences to the recommended (unsigned char) type
cast.

bin/named/unix/os.c

@@ -379,7 +379,7 @@ all_digits(const char *s) {
 		return (false);
 	}
 	while (*s != '\0') {
-		if (!isdigit((*s) & 0xff)) {
+		if (!isdigit((unsigned char)(*s))) {
 			return (false);
 		}
 		s++;

lib/bind9/check.c

@@ -11,6 +11,7 @@
 
 /*! \file */
 
+#include <ctype.h>
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stdlib.h>

lib/dns/dnssec.c

@@ -11,6 +11,7 @@
 
 /*! \file */
 
+#include <ctype.h>
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stdlib.h>
@@ -1433,8 +1434,7 @@ dns_dnssec_findmatchingkeys(const dns_name_t *origin, const char *directory,
 
 		alg = 0;
 		for (i = len + 1 + 1; i < dir.entry.length; i++) {
-			if (dir.entry.name[i] < '0' || dir.entry.name[i] > '9')
-			{
+			if (!isdigit((unsigned char)dir.entry.name[i])) {
 				break;
 			}
 			alg *= 10;
@@ -1452,15 +1452,8 @@ dns_dnssec_findmatchingkeys(const dns_name_t *origin, const char *directory,
 		}
 
 		for (i++; i < dir.entry.length; i++) {
-			if (dir.entry.name[i] < '0' || dir.entry.name[i] > '9')
-			{
+			if (!isdigit((unsigned char)dir.entry.name[i])) {
 				break;
-
-				/*
-				 * Did we not read exactly 5 more digits?
-				 * Did we overflow?
-				 * Did we correctly terminate?
-				 */
 			}
 		}
 

lib/dns/name.c

@@ -1204,7 +1204,7 @@ dns_name_fromtext(dns_name_t *name, isc_buffer_t *source,
 			POST(state);
 		/* FALLTHROUGH */
 		case ft_escape:
-			if (!isdigit(c & 0xff)) {
+			if (!isdigit((unsigned char)c)) {
 				if (count >= 63) {
 					return (DNS_R_LABELTOOLONG);
 				}
@@ -1224,7 +1224,7 @@ dns_name_fromtext(dns_name_t *name, isc_buffer_t *source,
 			state = ft_escdecimal;
 		/* FALLTHROUGH */
 		case ft_escdecimal:
-			if (!isdigit(c & 0xff)) {
+			if (!isdigit((unsigned char)c)) {
 				return (DNS_R_BADESCAPE);
 			}
 			value *= 10;

lib/dns/rcode.c

@@ -219,8 +219,8 @@ maybe_numeric(unsigned int *valuep, isc_textregion_t *source, unsigned int max,
 	char buffer[NUMBERSIZE];
 	int v;
 
-	if (!isdigit(source->base[0] & 0xff) || source->length > NUMBERSIZE - 1)
-	{
+	if (!isdigit((unsigned char)source->base[0]) ||
+	    source->length > NUMBERSIZE - 1) {
 		return (ISC_R_BADNUMBER);
 	}
 

lib/dns/rdata/generic/x25_19.c

@@ -35,7 +35,8 @@ fromtext_x25(ARGS_FROMTEXT) {
 		RETTOK(DNS_R_SYNTAX);
 	}
 	for (i = 0; i < token.value.as_textregion.length; i++) {
-		if (!isdigit(token.value.as_textregion.base[i] & 0xff)) {
+		if (!isdigit((unsigned char)token.value.as_textregion.base[i]))
+		{
 			RETTOK(ISC_R_RANGE);
 		}
 	}
@@ -125,7 +126,7 @@ fromstruct_x25(ARGS_FROMSTRUCT) {
 	}
 
 	for (i = 0; i < x25->x25_len; i++) {
-		if (!isdigit(x25->x25[i] & 0xff)) {
+		if (!isdigit((unsigned char)x25->x25[i])) {
 			return (ISC_R_RANGE);
 		}
 	}

lib/dns/rdata/in_1/atma_34.c

@@ -91,7 +91,7 @@ fromtext_in_atma(ARGS_FROMTEXT) {
 				lastwasperiod = true;
 				continue;
 			}
-			if ((sr->base[0] < '0') || (sr->base[0] > '9')) {
+			if (!isdigit((unsigned char)sr->base[0])) {
 				RETTOK(DNS_R_SYNTAX);
 			}
 			RETERR(mem_tobuffer(target, sr->base, 1));
@@ -157,7 +157,7 @@ fromwire_in_atma(ARGS_FROMWIRE) {
 	if (region.base[0] == 1) {
 		unsigned int i;
 		for (i = 1; i < region.length; i++) {
-			if (region.base[i] < '0' || region.base[i] > '9') {
+			if (!isdigit((unsigned char)region.base[i])) {
 				return (DNS_R_FORMERR);
 			}
 		}

lib/isc/tm.c

@@ -89,7 +89,7 @@ conv_num(const char **buf, int *dest, int llim, int ulim) {
 	/* The limit also determines the number of valid digits. */
 	int rulim = ulim;
 
-	if (**buf < '0' || **buf > '9') {
+	if (!isdigit((unsigned char)**buf)) {
 		return (0);
 	}
 

lib/isc/unix/dir.c

@@ -230,7 +230,7 @@ isc_dir_createunique(char *templet) {
 		 */
 		p = x;
 		while (*p != '\0') {
-			if (isdigit(*p & 0xff)) {
+			if (isdigit((unsigned char)*p)) {
 				*p = 'a';
 			} else if (*p != 'z') {
 				++*p;

lib/isc/win32/dir.c

@@ -273,7 +273,7 @@ isc_dir_createunique(char *templet) {
 		 */
 		p = x;
 		while (*p != '\0') {
-			if (isdigit(*p & 0xff)) {
+			if (isdigit((unsigned char)*p)) {
 				*p = 'a';
 			} else if (*p != 'z') {
 				++*p;

lib/isc/win32/file.c

@@ -102,7 +102,7 @@ gettemp(char *path, bool binary, int *doopen) {
 			if (*trv == 'z') {
 				*trv++ = 'a';
 			} else {
-				if (isdigit(*trv)) {
+				if (isdigit((unsigned char)*trv)) {
 					*trv = 'a';
 				} else {
 					++*trv;

lib/ns/query.c

@@ -11,6 +11,7 @@
 
 /*! \file */
 
+#include <ctype.h>
 #include <inttypes.h>
 #include <stdbool.h>
 #include <string.h>
@@ -5352,7 +5353,7 @@ get_root_key_sentinel_id(query_ctx_t *qctx, const char *ndata) {
 	int i;
 
 	for (i = 0; i < 5; i++) {
-		if (ndata[i] < '0' || ndata[i] > '9') {
+		if (!isdigit((unsigned char)ndata[i])) {
 			return (false);
 		}
 		v *= 10;