fix symtab-order-dependent spurious matches in dladdr
commit 8b8fb7f03721c42445f982582f462144ab60a1a0 added logic to prevent
matching a symbol with no recorded size (closest-match) when there is
an intervening symbol whose size was recorded, but it only worked when
the intervening symbol was encountered later in the search.
instead of rejecting symbols where addr falls outside their recorded
size during the closest-match search, accept them to find the true
closest-match, then reject such a result only once the search has
finished.
diff --git a/ldso/dynlink.c b/ldso/dynlink.c
index 31c5060..d963aea 100644
--- a/ldso/dynlink.c
+++ b/ldso/dynlink.c
@@ -1951,6 +1951,7 @@
uint32_t nsym;
char *strings;
size_t best = 0;
+ size_t besterr = -1;
pthread_rwlock_rdlock(&lock);
p = addr2dso(addr);
@@ -1968,6 +1969,7 @@
if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
best = (size_t)(p->funcdescs + idx);
bestsym = sym + idx;
+ besterr = 0;
}
}
@@ -1978,18 +1980,19 @@
size_t symaddr = (size_t)laddr(p, sym->st_value);
if (symaddr > addr || symaddr < best)
continue;
- if (sym->st_size && symaddr+sym->st_size <= addr) {
- best = 0;
- bestsym = 0;
- continue;
- }
best = symaddr;
bestsym = sym;
+ besterr = addr - symaddr;
if (addr == symaddr)
break;
}
}
+ if (bestsym && besterr > bestsym->st_size-1) {
+ best = 0;
+ bestsym = 0;
+ }
+
info->dli_fname = p->name;
info->dli_fbase = p->map;