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| //===-- asan_mac.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 AddressSanitizer, an address sanity checker.
//
// Mac-specific details.
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_platform.h"
#if SANITIZER_MAC
#include "asan_interceptors.h"
#include "asan_internal.h"
#include "asan_mapping.h"
#include "asan_stack.h"
#include "asan_thread.h"
#include "sanitizer_common/sanitizer_atomic.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "sanitizer_common/sanitizer_mac.h"
#include <dlfcn.h>
#include <fcntl.h>
#include <libkern/OSAtomic.h>
#include <mach-o/dyld.h>
#include <mach-o/getsect.h>
#include <mach-o/loader.h>
#include <pthread.h>
#include <stdlib.h> // for free()
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/sysctl.h>
#include <sys/ucontext.h>
#include <unistd.h>
// from <crt_externs.h>, but we don't have that file on iOS
extern "C" {
extern char ***_NSGetArgv(void);
extern char ***_NSGetEnviron(void);
}
namespace __asan {
void InitializePlatformInterceptors() {}
void InitializePlatformExceptionHandlers() {}
bool IsSystemHeapAddress (uptr addr) { return false; }
// No-op. Mac does not support static linkage anyway.
void *AsanDoesNotSupportStaticLinkage() {
return 0;
}
uptr FindDynamicShadowStart() {
uptr granularity = GetMmapGranularity();
uptr alignment = 8 * granularity;
uptr left_padding = granularity;
uptr space_size = kHighShadowEnd + left_padding;
uptr largest_gap_found = 0;
uptr max_occupied_addr = 0;
VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
uptr shadow_start =
FindAvailableMemoryRange(space_size, alignment, granularity,
&largest_gap_found, &max_occupied_addr);
// If the shadow doesn't fit, restrict the address space to make it fit.
if (shadow_start == 0) {
VReport(
2,
"Shadow doesn't fit, largest_gap_found = %p, max_occupied_addr = %p\n",
largest_gap_found, max_occupied_addr);
uptr new_max_vm = RoundDownTo(largest_gap_found << SHADOW_SCALE, alignment);
if (new_max_vm < max_occupied_addr) {
Report("Unable to find a memory range for dynamic shadow.\n");
Report(
"space_size = %p, largest_gap_found = %p, max_occupied_addr = %p, "
"new_max_vm = %p\n",
space_size, largest_gap_found, max_occupied_addr, new_max_vm);
CHECK(0 && "cannot place shadow");
}
RestrictMemoryToMaxAddress(new_max_vm);
kHighMemEnd = new_max_vm - 1;
space_size = kHighShadowEnd + left_padding;
VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
shadow_start = FindAvailableMemoryRange(space_size, alignment, granularity,
nullptr, nullptr);
if (shadow_start == 0) {
Report("Unable to find a memory range after restricting VM.\n");
CHECK(0 && "cannot place shadow after restricting vm");
}
}
CHECK_NE((uptr)0, shadow_start);
CHECK(IsAligned(shadow_start, alignment));
return shadow_start;
}
// No-op. Mac does not support static linkage anyway.
void AsanCheckDynamicRTPrereqs() {}
// No-op. Mac does not support static linkage anyway.
void AsanCheckIncompatibleRT() {}
void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
// Find the Mach-O header for the image containing the needle
Dl_info info;
int err = dladdr(needle, &info);
if (err == 0) return;
#if __LP64__
const struct mach_header_64 *mh = (struct mach_header_64 *)info.dli_fbase;
#else
const struct mach_header *mh = (struct mach_header *)info.dli_fbase;
#endif
// Look up the __asan_globals section in that image and register its globals
unsigned long size = 0;
__asan_global *globals = (__asan_global *)getsectiondata(
mh,
"__DATA", "__asan_globals",
&size);
if (!globals) return;
if (size % sizeof(__asan_global) != 0) return;
op(globals, size / sizeof(__asan_global));
}
void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
UNIMPLEMENTED();
}
// Support for the following functions from libdispatch on Mac OS:
// dispatch_async_f()
// dispatch_async()
// dispatch_sync_f()
// dispatch_sync()
// dispatch_after_f()
// dispatch_after()
// dispatch_group_async_f()
// dispatch_group_async()
// TODO(glider): libdispatch API contains other functions that we don't support
// yet.
//
// dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
// they can cause jobs to run on a thread different from the current one.
// TODO(glider): if so, we need a test for this (otherwise we should remove
// them).
//
// The following functions use dispatch_barrier_async_f() (which isn't a library
// function but is exported) and are thus supported:
// dispatch_source_set_cancel_handler_f()
// dispatch_source_set_cancel_handler()
// dispatch_source_set_event_handler_f()
// dispatch_source_set_event_handler()
//
// The reference manual for Grand Central Dispatch is available at
// http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
// The implementation details are at
// http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
typedef void* dispatch_group_t;
typedef void* dispatch_queue_t;
typedef void* dispatch_source_t;
typedef u64 dispatch_time_t;
typedef void (*dispatch_function_t)(void *block);
typedef void* (*worker_t)(void *block);
// A wrapper for the ObjC blocks used to support libdispatch.
typedef struct {
void *block;
dispatch_function_t func;
u32 parent_tid;
} asan_block_context_t;
ALWAYS_INLINE
void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
AsanThread *t = GetCurrentThread();
if (!t) {
t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
parent_tid, stack, /* detached */ true);
t->Init();
asanThreadRegistry().StartThread(t->tid(), GetTid(), ThreadType::Worker,
nullptr);
SetCurrentThread(t);
}
}
// For use by only those functions that allocated the context via
// alloc_asan_context().
extern "C"
void asan_dispatch_call_block_and_release(void *block) {
GET_STACK_TRACE_THREAD;
asan_block_context_t *context = (asan_block_context_t*)block;
VReport(2,
"asan_dispatch_call_block_and_release(): "
"context: %p, pthread_self: %p\n",
block, pthread_self());
asan_register_worker_thread(context->parent_tid, &stack);
// Call the original dispatcher for the block.
context->func(context->block);
asan_free(context, &stack, FROM_MALLOC);
}
} // namespace __asan
using namespace __asan;
// Wrap |ctxt| and |func| into an asan_block_context_t.
// The caller retains control of the allocated context.
extern "C"
asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
BufferedStackTrace *stack) {
asan_block_context_t *asan_ctxt =
(asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
asan_ctxt->block = ctxt;
asan_ctxt->func = func;
asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
return asan_ctxt;
}
// Define interceptor for dispatch_*_f function with the three most common
// parameters: dispatch_queue_t, context, dispatch_function_t.
#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f) \
INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt, \
dispatch_function_t func) { \
GET_STACK_TRACE_THREAD; \
asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
if (Verbosity() >= 2) { \
Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n", \
asan_ctxt, pthread_self()); \
PRINT_CURRENT_STACK(); \
} \
return REAL(dispatch_x_f)(dq, (void*)asan_ctxt, \
asan_dispatch_call_block_and_release); \
}
INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
dispatch_queue_t dq, void *ctxt,
dispatch_function_t func) {
GET_STACK_TRACE_THREAD;
asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
if (Verbosity() >= 2) {
Report("dispatch_after_f: %p\n", asan_ctxt);
PRINT_CURRENT_STACK();
}
return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
asan_dispatch_call_block_and_release);
}
INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
dispatch_queue_t dq, void *ctxt,
dispatch_function_t func) {
GET_STACK_TRACE_THREAD;
asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
if (Verbosity() >= 2) {
Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
asan_ctxt, pthread_self());
PRINT_CURRENT_STACK();
}
REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
asan_dispatch_call_block_and_release);
}
#if !defined(MISSING_BLOCKS_SUPPORT)
extern "C" {
void dispatch_async(dispatch_queue_t dq, void(^work)(void));
void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
void(^work)(void));
void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
void(^work)(void));
void dispatch_source_set_cancel_handler(dispatch_source_t ds,
void(^work)(void));
void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
}
#define GET_ASAN_BLOCK(work) \
void (^asan_block)(void); \
int parent_tid = GetCurrentTidOrInvalid(); \
asan_block = ^(void) { \
GET_STACK_TRACE_THREAD; \
asan_register_worker_thread(parent_tid, &stack); \
work(); \
}
INTERCEPTOR(void, dispatch_async,
dispatch_queue_t dq, void(^work)(void)) {
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_async)(dq, asan_block);
}
INTERCEPTOR(void, dispatch_group_async,
dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_group_async)(dg, dq, asan_block);
}
INTERCEPTOR(void, dispatch_after,
dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_after)(when, queue, asan_block);
}
INTERCEPTOR(void, dispatch_source_set_cancel_handler,
dispatch_source_t ds, void(^work)(void)) {
if (!work) {
REAL(dispatch_source_set_cancel_handler)(ds, work);
return;
}
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
}
INTERCEPTOR(void, dispatch_source_set_event_handler,
dispatch_source_t ds, void(^work)(void)) {
ENABLE_FRAME_POINTER;
GET_ASAN_BLOCK(work);
REAL(dispatch_source_set_event_handler)(ds, asan_block);
}
#endif
#endif // SANITIZER_MAC
|