Re: Undefined int shift in ifwatchd

[Martin Husemann <martin%duskware.de@localhost>]

On Wed, Jan 27, 2016 at 07:53:27PM +0100, Martin Husemann wrote:
> How about defining a RTA_ALL_MASK (or however we'd call it, defined as
> 0x1ff) and write:
> 
> 	for (i = 1; i & RTA_ALL_MASK; i <<= 1) {
> 
> ?

Or without global header changes, just use ffs() ?

Martin

Index: ifwatchd.c
===================================================================
RCS file: /cvsroot/src/usr.sbin/ifwatchd/ifwatchd.c,v
retrieving revision 1.27
diff -u -p -r1.27 ifwatchd.c
--- ifwatchd.c	27 Jan 2016 18:55:51 -0000	1.27
+++ ifwatchd.c	27 Jan 2016 19:31:10 -0000
@@ -65,7 +65,7 @@ enum event { ARRIVAL, DEPARTURE, UP, DOW
 /* local functions */
 __dead static void usage(void);
 static void dispatch(void*, size_t);
-static void check_addrs(char *cp, int addrs, enum event ev);
+static void check_addrs(char *cp, unsigned int addrs, enum event ev);
 static void invoke_script(struct sockaddr *sa, struct sockaddr *dst, enum event ev, int ifindex, const char *ifname_hint);
 static void list_interfaces(const char *ifnames);
 static void check_announce(struct if_announcemsghdr *ifan);
@@ -287,32 +287,44 @@ work:
 }
 
 static void
-check_addrs(char *cp, int addrs, enum event ev)
+check_addrs(char *cp, unsigned int addrs, enum event ev)
 {
 	struct sockaddr *sa, *ifa = NULL, *brd = NULL;
 	char ifname_buf[IFNAMSIZ];
 	const char *ifname;
 	int ifndx = 0;
-	unsigned i;
+	unsigned int i;
 
 	if (addrs == 0)
 		return;
-	for (i = 1; i; i <<= 1) {
-		if ((i & addrs) == 0)
-			continue;
+
+	for (;;) {
+		i = ffs(addrs);
+		if (i == 0)
+			break;
+		addrs &= ~i;
+
 		sa = (struct sockaddr *)cp;
-		if (i == RTA_IFP) {
+		switch (i) {
+		case RTA_IFP:
+		{
 			struct sockaddr_dl * li = (struct sockaddr_dl*)sa;
 			ifndx = li->sdl_index;
 			if (!find_interface(ifndx)) {
 				if (verbose)
-					printf("ignoring change on interface #%d\n", ifndx);
+					printf("ignoring change on "
+					    "interface #%d\n", ifndx);
 				return;
 			}
-		} else if (i == RTA_IFA)
+			break;
+		}
+		case RTA_IFA:
 			ifa = sa;
-		else if (i == RTA_BRD)
+			break;
+		case RTA_BRD:
 			brd = sa;
+			break;
+		}
 		RT_ADVANCE(cp, sa);
 	}
 	if (ifa != NULL) {