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//===-- asan_globals.cc ---------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Handle globals.
//===----------------------------------------------------------------------===//
#include "asan_interceptors.h"
#include "asan_internal.h"
#include "asan_mapping.h"
#include "asan_poisoning.h"
#include "asan_report.h"
#include "asan_stack.h"
#include "asan_stats.h"
#include "asan_thread.h"
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_mutex.h"
#include "sanitizer_common/sanitizer_placement_new.h"
namespace __asan {
typedef __asan_global Global;
struct ListOfGlobals {
const Global *g;
ListOfGlobals *next;
};
static BlockingMutex mu_for_globals(LINKER_INITIALIZED);
static LowLevelAllocator allocator_for_globals;
static ListOfGlobals *list_of_all_globals;
static const int kDynamicInitGlobalsInitialCapacity = 512;
struct DynInitGlobal {
Global g;
bool initialized;
};
typedef InternalMmapVector<DynInitGlobal> VectorOfGlobals;
// Lazy-initialized and never deleted.
static VectorOfGlobals *dynamic_init_globals;
ALWAYS_INLINE void PoisonShadowForGlobal(const Global *g, u8 value) {
FastPoisonShadow(g->beg, g->size_with_redzone, value);
}
ALWAYS_INLINE void PoisonRedZones(const Global &g) {
uptr aligned_size = RoundUpTo(g.size, SHADOW_GRANULARITY);
FastPoisonShadow(g.beg + aligned_size, g.size_with_redzone - aligned_size,
kAsanGlobalRedzoneMagic);
if (g.size != aligned_size) {
FastPoisonShadowPartialRightRedzone(
g.beg + RoundDownTo(g.size, SHADOW_GRANULARITY),
g.size % SHADOW_GRANULARITY,
SHADOW_GRANULARITY,
kAsanGlobalRedzoneMagic);
}
}
static void ReportGlobal(const Global &g, const char *prefix) {
Report("%s Global: beg=%p size=%zu/%zu name=%s module=%s dyn_init=%zu\n",
prefix, (void*)g.beg, g.size, g.size_with_redzone, g.name,
g.module_name, g.has_dynamic_init);
}
bool DescribeAddressIfGlobal(uptr addr, uptr size) {
if (!flags()->report_globals) return false;
BlockingMutexLock lock(&mu_for_globals);
bool res = false;
for (ListOfGlobals *l = list_of_all_globals; l; l = l->next) {
const Global &g = *l->g;
if (flags()->report_globals >= 2)
ReportGlobal(g, "Search");
res |= DescribeAddressRelativeToGlobal(addr, size, g);
}
return res;
}
// Register a global variable.
// This function may be called more than once for every global
// so we store the globals in a map.
static void RegisterGlobal(const Global *g) {
CHECK(asan_inited);
if (flags()->report_globals >= 2)
ReportGlobal(*g, "Added");
CHECK(flags()->report_globals);
CHECK(AddrIsInMem(g->beg));
CHECK(AddrIsAlignedByGranularity(g->beg));
CHECK(AddrIsAlignedByGranularity(g->size_with_redzone));
if (flags()->poison_heap)
PoisonRedZones(*g);
ListOfGlobals *l = new(allocator_for_globals) ListOfGlobals;
l->g = g;
l->next = list_of_all_globals;
list_of_all_globals = l;
if (g->has_dynamic_init) {
if (dynamic_init_globals == 0) {
dynamic_init_globals = new(allocator_for_globals)
VectorOfGlobals(kDynamicInitGlobalsInitialCapacity);
}
DynInitGlobal dyn_global = { *g, false };
dynamic_init_globals->push_back(dyn_global);
}
}
static void UnregisterGlobal(const Global *g) {
CHECK(asan_inited);
CHECK(flags()->report_globals);
CHECK(AddrIsInMem(g->beg));
CHECK(AddrIsAlignedByGranularity(g->beg));
CHECK(AddrIsAlignedByGranularity(g->size_with_redzone));
if (flags()->poison_heap)
PoisonShadowForGlobal(g, 0);
// We unpoison the shadow memory for the global but we do not remove it from
// the list because that would require O(n^2) time with the current list
// implementation. It might not be worth doing anyway.
}
void StopInitOrderChecking() {
BlockingMutexLock lock(&mu_for_globals);
if (!flags()->check_initialization_order || !dynamic_init_globals)
return;
flags()->check_initialization_order = false;
for (uptr i = 0, n = dynamic_init_globals->size(); i < n; ++i) {
DynInitGlobal &dyn_g = (*dynamic_init_globals)[i];
const Global *g = &dyn_g.g;
// Unpoison the whole global.
PoisonShadowForGlobal(g, 0);
// Poison redzones back.
PoisonRedZones(*g);
}
}
} // namespace __asan
// ---------------------- Interface ---------------- {{{1
using namespace __asan; // NOLINT
// Register an array of globals.
void __asan_register_globals(__asan_global *globals, uptr n) {
if (!flags()->report_globals) return;
BlockingMutexLock lock(&mu_for_globals);
for (uptr i = 0; i < n; i++) {
RegisterGlobal(&globals[i]);
}
}
// Unregister an array of globals.
// We must do this when a shared objects gets dlclosed.
void __asan_unregister_globals(__asan_global *globals, uptr n) {
if (!flags()->report_globals) return;
BlockingMutexLock lock(&mu_for_globals);
for (uptr i = 0; i < n; i++) {
UnregisterGlobal(&globals[i]);
}
}
// This method runs immediately prior to dynamic initialization in each TU,
// when all dynamically initialized globals are unpoisoned. This method
// poisons all global variables not defined in this TU, so that a dynamic
// initializer can only touch global variables in the same TU.
void __asan_before_dynamic_init(const char *module_name) {
if (!flags()->check_initialization_order ||
!flags()->poison_heap)
return;
bool strict_init_order = flags()->strict_init_order;
CHECK(dynamic_init_globals);
CHECK(module_name);
CHECK(asan_inited);
BlockingMutexLock lock(&mu_for_globals);
if (flags()->report_globals >= 3)
Printf("DynInitPoison module: %s\n", module_name);
for (uptr i = 0, n = dynamic_init_globals->size(); i < n; ++i) {
DynInitGlobal &dyn_g = (*dynamic_init_globals)[i];
const Global *g = &dyn_g.g;
if (dyn_g.initialized)
continue;
if (g->module_name != module_name)
PoisonShadowForGlobal(g, kAsanInitializationOrderMagic);
else if (!strict_init_order)
dyn_g.initialized = true;
}
}
// This method runs immediately after dynamic initialization in each TU, when
// all dynamically initialized globals except for those defined in the current
// TU are poisoned. It simply unpoisons all dynamically initialized globals.
void __asan_after_dynamic_init() {
if (!flags()->check_initialization_order ||
!flags()->poison_heap)
return;
CHECK(asan_inited);
BlockingMutexLock lock(&mu_for_globals);
// FIXME: Optionally report that we're unpoisoning globals from a module.
for (uptr i = 0, n = dynamic_init_globals->size(); i < n; ++i) {
DynInitGlobal &dyn_g = (*dynamic_init_globals)[i];
const Global *g = &dyn_g.g;
if (!dyn_g.initialized) {
// Unpoison the whole global.
PoisonShadowForGlobal(g, 0);
// Poison redzones back.
PoisonRedZones(*g);
}
}
}
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