re PR sanitizer/71160 (libasan: Backport support for malloc within dlsym)

	PR sanitizer/71160
	* asan/asan_malloc_linux.cc: Cherry pick upstream r254395
	and r269633.

From-SVN: r236314

libsanitizer/ChangeLog

+2016-05-17  Jakub Jelinek  <jakub@redhat.com>
+
+	PR sanitizer/71160
+	* asan/asan_malloc_linux.cc: Cherry pick upstream r254395
+	and r269633.
+
 2016-04-21  Maxim Ostapenko  <m.ostapenko@samsung.com>
 
 	PR sanitizer/70624

libsanitizer/asan/asan_malloc_linux.cc

@@ -24,39 +24,62 @@
 // ---------------------- Replacement functions ---------------- {{{1
 using namespace __asan;  // NOLINT
 
+static uptr allocated_for_dlsym;
+static const uptr kDlsymAllocPoolSize = 1024;
+static uptr alloc_memory_for_dlsym[kDlsymAllocPoolSize];
+
+static bool IsInDlsymAllocPool(const void *ptr) {
+  uptr off = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
+  return off < sizeof(alloc_memory_for_dlsym);
+}
+
+static void *AllocateFromLocalPool(uptr size_in_bytes) {
+  uptr size_in_words = RoundUpTo(size_in_bytes, kWordSize) / kWordSize;
+  void *mem = (void*)&alloc_memory_for_dlsym[allocated_for_dlsym];
+  allocated_for_dlsym += size_in_words;
+  CHECK_LT(allocated_for_dlsym, kDlsymAllocPoolSize);
+  return mem;
+}
+
 INTERCEPTOR(void, free, void *ptr) {
   GET_STACK_TRACE_FREE;
+  if (UNLIKELY(IsInDlsymAllocPool(ptr)))
+    return;
   asan_free(ptr, &stack, FROM_MALLOC);
 }
 
 INTERCEPTOR(void, cfree, void *ptr) {
   GET_STACK_TRACE_FREE;
+  if (UNLIKELY(IsInDlsymAllocPool(ptr)))
+    return;
   asan_free(ptr, &stack, FROM_MALLOC);
 }
 
 INTERCEPTOR(void*, malloc, uptr size) {
+  if (UNLIKELY(!asan_inited))
+    // Hack: dlsym calls malloc before REAL(malloc) is retrieved from dlsym.
+    return AllocateFromLocalPool(size);
   GET_STACK_TRACE_MALLOC;
   return asan_malloc(size, &stack);
 }
 
 INTERCEPTOR(void*, calloc, uptr nmemb, uptr size) {
-  if (UNLIKELY(!asan_inited)) {
+  if (UNLIKELY(!asan_inited))
     // Hack: dlsym calls calloc before REAL(calloc) is retrieved from dlsym.
-    const uptr kCallocPoolSize = 1024;
-    static uptr calloc_memory_for_dlsym[kCallocPoolSize];
-    static uptr allocated;
-    uptr size_in_words = ((nmemb * size) + kWordSize - 1) / kWordSize;
-    void *mem = (void*)&calloc_memory_for_dlsym[allocated];
-    allocated += size_in_words;
-    CHECK(allocated < kCallocPoolSize);
-    return mem;
-  }
+    return AllocateFromLocalPool(nmemb * size);
   GET_STACK_TRACE_MALLOC;
   return asan_calloc(nmemb, size, &stack);
 }
 
 INTERCEPTOR(void*, realloc, void *ptr, uptr size) {
   GET_STACK_TRACE_MALLOC;
+  if (UNLIKELY(IsInDlsymAllocPool(ptr))) {
+    uptr offset = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
+    uptr copy_size = Min(size, kDlsymAllocPoolSize - offset);
+    void *new_ptr = asan_malloc(size, &stack);
+    internal_memcpy(new_ptr, ptr, copy_size);
+    return new_ptr;
+  }
   return asan_realloc(ptr, size, &stack);
 }