loader: factor out guard location setup from Realloc

To simplify and make it easier to read, use ga_Bytes field from guard
structure.

diff --git a/stand/libsa/zalloc_malloc.c b/stand/libsa/zalloc_malloc.c
index 2cc14d80641d5e71b718137a2e1d739e4027403b..f0eddb12317889e04187d97bcedcdcfe67fdeba8 100644 (file)
--- a/stand/libsa/zalloc_malloc.c
+++ b/stand/libsa/zalloc_malloc.c
@@ -156,7 +156,9 @@ Realloc(void *ptr, size_t size, const char *file, int line)
 
     if ((res = Malloc(size, file, line)) != NULL) {
        if (ptr) {
-           old = *(size_t *)((char *)ptr - MALLOCALIGN) - MALLOCALIGN;
+           Guard *g = (Guard *)((char *)ptr - MALLOCALIGN);
+
+           old = g->ga_Bytes - MALLOCALIGN;
            if (old < size)
                bcopy(ptr, res, old);
            else