added protection against race condition

between first and second pass of converting
[]int to string.

R=r
OCL=29467
CL=29467

diff --git a/src/runtime/string.c b/src/runtime/string.c
index 04cf06bc3c86ce30edb7041fbdbe3c3d0243c393..5bfe8196f75e88262a3924250fdff0a682f69557 100644 (file)
--- a/src/runtime/string.c
+++ b/src/runtime/string.c
@@ -184,21 +184,25 @@ sys·arraystring(Array b, String s)
 void
 sys·arraystringi(Array b, String s)
 {
-       int32 siz, i;
+       int32 siz1, siz2, i;
        int32 *a;
        byte dum[8];
 
        a = (int32*)b.array;
-       siz = 0;
+       siz1 = 0;
        for(i=0; i<b.nel; i++) {
-               siz += runetochar(dum, a[i]);
+               siz1 += runetochar(dum, a[i]);
        }
 
-       s = gostringsize(siz);
-       siz = 0;
+       s = gostringsize(siz1+4);
+       siz2 = 0;
        for(i=0; i<b.nel; i++) {
-               siz += runetochar(s.str+siz, a[i]);
+               // check for race
+               if(siz2 >= siz1)
+                       break;
+               siz2 += runetochar(s.str+siz2, a[i]);
        }
+       s.len = siz2;
 
        FLUSH(&s);
 }