Re: Undefined int shift in ifwatchd

[Martin Husemann]

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) {