malloc_hook.cpp
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// RUN: %clangxx -O2 %s -o %t && %run %t 2>&1 | FileCheck %s
// Malloc/free hooks are not supported on Windows.
// XFAIL: windows-msvc
// XFAIL: ubsan
#include <stdlib.h>
#include <unistd.h>
#include <sanitizer/allocator_interface.h>
extern "C" {
const volatile void *global_ptr;
#define WRITE(s) write(1, s, sizeof(s))
// Note: avoid calling functions that allocate memory in malloc/free
// to avoid infinite recursion.
void __sanitizer_malloc_hook(const volatile void *ptr, size_t sz) {
if (__sanitizer_get_ownership(ptr) && sz == 4) {
WRITE("MallocHook\n");
global_ptr = ptr;
}
}
void __sanitizer_free_hook(const volatile void *ptr) {
if (__sanitizer_get_ownership(ptr) && ptr == global_ptr)
WRITE("FreeHook\n");
}
} // extern "C"
volatile int *x;
void MallocHook1(const volatile void *ptr, size_t sz) { WRITE("MH1\n"); }
void MallocHook2(const volatile void *ptr, size_t sz) { WRITE("MH2\n"); }
void FreeHook1(const volatile void *ptr) { WRITE("FH1\n"); }
void FreeHook2(const volatile void *ptr) { WRITE("FH2\n"); }
// Call this function with uninitialized arguments to poison
// TLS shadow for function parameters before calling operator
// new and, eventually, user-provided hook.
__attribute__((noinline)) void allocate(int *unused1, int *unused2) {
x = new int;
}
int main() {
__sanitizer_install_malloc_and_free_hooks(MallocHook1, FreeHook1);
__sanitizer_install_malloc_and_free_hooks(MallocHook2, FreeHook2);
int *undef1, *undef2;
allocate(undef1, undef2);
// CHECK: MallocHook
// CHECK: MH1
// CHECK: MH2
// Check that malloc hook was called with correct argument.
if (global_ptr != (void*)x) {
_exit(1);
}
*x = 0;
delete x;
// CHECK: FreeHook
// CHECK: FH1
// CHECK: FH2
return 0;
}