1//===-- asan_mac.cc -------------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file is a part of AddressSanitizer, an address sanity checker.
11//
12// Mac-specific details.
13//===----------------------------------------------------------------------===//
14
15#include "sanitizer_common/sanitizer_platform.h"
16#if SANITIZER_MAC
17
18#include "asan_interceptors.h"
19#include "asan_internal.h"
20#include "asan_mapping.h"
21#include "asan_stack.h"
22#include "asan_thread.h"
23#include "sanitizer_common/sanitizer_atomic.h"
24#include "sanitizer_common/sanitizer_libc.h"
25#include "sanitizer_common/sanitizer_mac.h"
26
27#include <fcntl.h>
28#include <libkern/OSAtomic.h>
29#include <mach-o/dyld.h>
30#include <mach-o/loader.h>
31#include <pthread.h>
32#include <stdlib.h>  // for free()
33#include <sys/mman.h>
34#include <sys/resource.h>
35#include <sys/sysctl.h>
36#include <sys/ucontext.h>
37#include <unistd.h>
38
39namespace __asan {
40
41void InitializePlatformInterceptors() {}
42
43bool PlatformHasDifferentMemcpyAndMemmove() {
44  // On OS X 10.7 memcpy() and memmove() are both resolved
45  // into memmove$VARIANT$sse42.
46  // See also https://github.com/google/sanitizers/issues/34.
47  // TODO(glider): need to check dynamically that memcpy() and memmove() are
48  // actually the same function.
49  return GetMacosVersion() == MACOS_VERSION_SNOW_LEOPARD;
50}
51
52// No-op. Mac does not support static linkage anyway.
53void *AsanDoesNotSupportStaticLinkage() {
54  return 0;
55}
56
57// No-op. Mac does not support static linkage anyway.
58void AsanCheckDynamicRTPrereqs() {}
59
60// No-op. Mac does not support static linkage anyway.
61void AsanCheckIncompatibleRT() {}
62
63void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
64  UNIMPLEMENTED();
65}
66
67// Support for the following functions from libdispatch on Mac OS:
68//   dispatch_async_f()
69//   dispatch_async()
70//   dispatch_sync_f()
71//   dispatch_sync()
72//   dispatch_after_f()
73//   dispatch_after()
74//   dispatch_group_async_f()
75//   dispatch_group_async()
76// TODO(glider): libdispatch API contains other functions that we don't support
77// yet.
78//
79// dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
80// they can cause jobs to run on a thread different from the current one.
81// TODO(glider): if so, we need a test for this (otherwise we should remove
82// them).
83//
84// The following functions use dispatch_barrier_async_f() (which isn't a library
85// function but is exported) and are thus supported:
86//   dispatch_source_set_cancel_handler_f()
87//   dispatch_source_set_cancel_handler()
88//   dispatch_source_set_event_handler_f()
89//   dispatch_source_set_event_handler()
90//
91// The reference manual for Grand Central Dispatch is available at
92//   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
93// The implementation details are at
94//   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
95
96typedef void* dispatch_group_t;
97typedef void* dispatch_queue_t;
98typedef void* dispatch_source_t;
99typedef u64 dispatch_time_t;
100typedef void (*dispatch_function_t)(void *block);
101typedef void* (*worker_t)(void *block);
102
103// A wrapper for the ObjC blocks used to support libdispatch.
104typedef struct {
105  void *block;
106  dispatch_function_t func;
107  u32 parent_tid;
108} asan_block_context_t;
109
110ALWAYS_INLINE
111void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
112  AsanThread *t = GetCurrentThread();
113  if (!t) {
114    t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
115                           parent_tid, stack, /* detached */ true);
116    t->Init();
117    asanThreadRegistry().StartThread(t->tid(), 0, 0);
118    SetCurrentThread(t);
119  }
120}
121
122// For use by only those functions that allocated the context via
123// alloc_asan_context().
124extern "C"
125void asan_dispatch_call_block_and_release(void *block) {
126  GET_STACK_TRACE_THREAD;
127  asan_block_context_t *context = (asan_block_context_t*)block;
128  VReport(2,
129          "asan_dispatch_call_block_and_release(): "
130          "context: %p, pthread_self: %p\n",
131          block, pthread_self());
132  asan_register_worker_thread(context->parent_tid, &stack);
133  // Call the original dispatcher for the block.
134  context->func(context->block);
135  asan_free(context, &stack, FROM_MALLOC);
136}
137
138}  // namespace __asan
139
140using namespace __asan;  // NOLINT
141
142// Wrap |ctxt| and |func| into an asan_block_context_t.
143// The caller retains control of the allocated context.
144extern "C"
145asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
146                                         BufferedStackTrace *stack) {
147  asan_block_context_t *asan_ctxt =
148      (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
149  asan_ctxt->block = ctxt;
150  asan_ctxt->func = func;
151  asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
152  return asan_ctxt;
153}
154
155// Define interceptor for dispatch_*_f function with the three most common
156// parameters: dispatch_queue_t, context, dispatch_function_t.
157#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
158  INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
159                                  dispatch_function_t func) {                 \
160    GET_STACK_TRACE_THREAD;                                                   \
161    asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
162    if (Verbosity() >= 2) {                                     \
163      Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
164             asan_ctxt, pthread_self());                                      \
165      PRINT_CURRENT_STACK();                                                  \
166    }                                                                         \
167    return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                           \
168                              asan_dispatch_call_block_and_release);          \
169  }
170
171INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
172INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
173INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
174
175INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
176                                    dispatch_queue_t dq, void *ctxt,
177                                    dispatch_function_t func) {
178  GET_STACK_TRACE_THREAD;
179  asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
180  if (Verbosity() >= 2) {
181    Report("dispatch_after_f: %p\n", asan_ctxt);
182    PRINT_CURRENT_STACK();
183  }
184  return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
185                                asan_dispatch_call_block_and_release);
186}
187
188INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
189                                          dispatch_queue_t dq, void *ctxt,
190                                          dispatch_function_t func) {
191  GET_STACK_TRACE_THREAD;
192  asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
193  if (Verbosity() >= 2) {
194    Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
195           asan_ctxt, pthread_self());
196    PRINT_CURRENT_STACK();
197  }
198  REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
199                               asan_dispatch_call_block_and_release);
200}
201
202#if !defined(MISSING_BLOCKS_SUPPORT)
203extern "C" {
204void dispatch_async(dispatch_queue_t dq, void(^work)(void));
205void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
206                          void(^work)(void));
207void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
208                    void(^work)(void));
209void dispatch_source_set_cancel_handler(dispatch_source_t ds,
210                                        void(^work)(void));
211void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
212}
213
214#define GET_ASAN_BLOCK(work) \
215  void (^asan_block)(void);  \
216  int parent_tid = GetCurrentTidOrInvalid(); \
217  asan_block = ^(void) { \
218    GET_STACK_TRACE_THREAD; \
219    asan_register_worker_thread(parent_tid, &stack); \
220    work(); \
221  }
222
223INTERCEPTOR(void, dispatch_async,
224            dispatch_queue_t dq, void(^work)(void)) {
225  ENABLE_FRAME_POINTER;
226  GET_ASAN_BLOCK(work);
227  REAL(dispatch_async)(dq, asan_block);
228}
229
230INTERCEPTOR(void, dispatch_group_async,
231            dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
232  ENABLE_FRAME_POINTER;
233  GET_ASAN_BLOCK(work);
234  REAL(dispatch_group_async)(dg, dq, asan_block);
235}
236
237INTERCEPTOR(void, dispatch_after,
238            dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
239  ENABLE_FRAME_POINTER;
240  GET_ASAN_BLOCK(work);
241  REAL(dispatch_after)(when, queue, asan_block);
242}
243
244INTERCEPTOR(void, dispatch_source_set_cancel_handler,
245            dispatch_source_t ds, void(^work)(void)) {
246  if (!work) {
247    REAL(dispatch_source_set_cancel_handler)(ds, work);
248    return;
249  }
250  ENABLE_FRAME_POINTER;
251  GET_ASAN_BLOCK(work);
252  REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
253}
254
255INTERCEPTOR(void, dispatch_source_set_event_handler,
256            dispatch_source_t ds, void(^work)(void)) {
257  ENABLE_FRAME_POINTER;
258  GET_ASAN_BLOCK(work);
259  REAL(dispatch_source_set_event_handler)(ds, asan_block);
260}
261#endif
262
263#endif  // SANITIZER_MAC
264