multibreak-rework-avoiding-race-20051215

avoid a potential race finding the correct connection during
MultiBreakCallBack_r

diff --git a/src/viced/callback.c b/src/viced/callback.c
index 8b25dfc..4ad97f4 100644 (file)
--- a/src/viced/callback.c
+++ b/src/viced/callback.c
@@ -778,6 +778,7 @@ MultiBreakCallBack_r(struct cbstruct cba[], int ncbas,
     int i, j;
     struct rx_connection *conns[MAX_CB_HOSTS];
     static struct AFSCBs tc = { 0, 0 };
+    int multi_to_cba_map[MAX_CB_HOSTS];
 
     assert(ncbas <= MAX_CB_HOSTS);
 
@@ -788,6 +789,7 @@ MultiBreakCallBack_r(struct cbstruct cba[], int ncbas,
            continue;
        }
        rx_GetConnection(thishost->callback_rxcon);
+       multi_to_cba_map[j] = i;
        conns[j++] = thishost->callback_rxcon;
 
 #ifdef ADAPT_MTU
@@ -806,28 +808,14 @@ MultiBreakCallBack_r(struct cbstruct cba[], int ncbas,
                struct host *hp;
                char hoststr[16];
 
-               idx = 0;
-               /* If there's an error, we have to hunt for the right host. 
-                * The conns array _should_ correspond one-to-one to the cba
-                * array, except in some rare cases it might be missing one 
-                * or more elements.  So the optimistic case is almost 
-                * always right.  At worst, it's the starting point for the 
-                * hunt. */
-               for (hp = 0, i = multi_i; i < j; i++) {
-                   hp = cba[i].hp;     /* optimistic, but usually right */
-                   if (!hp) {
-                       break;
-                   }
-                   if (conns[multi_i] == hp->callback_rxcon) {
-                       idx = cba[i].thead;
-                       break;
-                   }
-               }
+               i = multi_to_cba_map[multi_i];
+               hp = cba[i].hp;
+               idx = cba[i].thead;
 
-               if (!hp) {
+               if (!hp || !idx) {
                    ViceLog(0,
-                           ("BCB: INTERNAL ERROR: hp=%x, cba=%x\n", hp,
-                            cba));
+                           ("BCB: INTERNAL ERROR: hp=%x, cba=%x, thead=%u\n", 
+                            hp, cba, idx));
                } else {
                    /* 
                     ** try breaking callbacks on alternate interface addresses