dfsan_interceptors.cpp
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//===-- dfsan_interceptors.cpp --------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of DataFlowSanitizer.
//
// Interceptors for standard library functions.
//===----------------------------------------------------------------------===//
#include <sys/syscall.h>
#include <unistd.h>
#include "dfsan/dfsan.h"
#include "interception/interception.h"
#include "sanitizer_common/sanitizer_common.h"
using namespace __sanitizer;
static bool interceptors_initialized;
INTERCEPTOR(void *, mmap, void *addr, SIZE_T length, int prot, int flags,
int fd, OFF_T offset) {
void *res;
// interceptors_initialized is set to true during preinit_array, when we're
// single-threaded. So we don't need to worry about accessing it atomically.
if (!interceptors_initialized)
res = (void *)syscall(__NR_mmap, addr, length, prot, flags, fd, offset);
else
res = REAL(mmap)(addr, length, prot, flags, fd, offset);
if (res != (void *)-1)
dfsan_set_label(0, res, RoundUpTo(length, GetPageSize()));
return res;
}
INTERCEPTOR(void *, mmap64, void *addr, SIZE_T length, int prot, int flags,
int fd, OFF64_T offset) {
void *res = REAL(mmap64)(addr, length, prot, flags, fd, offset);
if (res != (void *)-1)
dfsan_set_label(0, res, RoundUpTo(length, GetPageSize()));
return res;
}
INTERCEPTOR(int, munmap, void *addr, SIZE_T length) {
int res = REAL(munmap)(addr, length);
if (res != -1) {
uptr beg_shadow_addr = (uptr)__dfsan::shadow_for(addr);
void *end_addr =
(void *)((uptr)addr + RoundUpTo(length, GetPageSizeCached()));
uptr end_shadow_addr = (uptr)__dfsan::shadow_for(end_addr);
ReleaseMemoryPagesToOS(beg_shadow_addr, end_shadow_addr);
}
return res;
}
namespace __dfsan {
void InitializeInterceptors() {
CHECK(!interceptors_initialized);
INTERCEPT_FUNCTION(mmap);
INTERCEPT_FUNCTION(mmap64);
INTERCEPT_FUNCTION(munmap);
interceptors_initialized = true;
}
} // namespace __dfsan