1//===-- lsan_mac.cpp ------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file is a part of LeakSanitizer, a memory leak checker.
10//
11// Mac-specific details.
12//===----------------------------------------------------------------------===//
13
14#include "sanitizer_common/sanitizer_platform.h"
15#if SANITIZER_APPLE
16
17#include "interception/interception.h"
18#include "lsan.h"
19#include "lsan_allocator.h"
20#include "lsan_thread.h"
21
22#include <pthread.h>
23
24namespace __lsan {
25// Support for the following functions from libdispatch on Mac OS:
26//   dispatch_async_f()
27//   dispatch_async()
28//   dispatch_sync_f()
29//   dispatch_sync()
30//   dispatch_after_f()
31//   dispatch_after()
32//   dispatch_group_async_f()
33//   dispatch_group_async()
34// TODO(glider): libdispatch API contains other functions that we don't support
35// yet.
36//
37// dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
38// they can cause jobs to run on a thread different from the current one.
39// TODO(glider): if so, we need a test for this (otherwise we should remove
40// them).
41//
42// The following functions use dispatch_barrier_async_f() (which isn't a library
43// function but is exported) and are thus supported:
44//   dispatch_source_set_cancel_handler_f()
45//   dispatch_source_set_cancel_handler()
46//   dispatch_source_set_event_handler_f()
47//   dispatch_source_set_event_handler()
48//
49// The reference manual for Grand Central Dispatch is available at
50//   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
51// The implementation details are at
52//   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
53
54typedef void *dispatch_group_t;
55typedef void *dispatch_queue_t;
56typedef void *dispatch_source_t;
57typedef u64 dispatch_time_t;
58typedef void (*dispatch_function_t)(void *block);
59typedef void *(*worker_t)(void *block);
60
61// A wrapper for the ObjC blocks used to support libdispatch.
62typedef struct {
63  void *block;
64  dispatch_function_t func;
65  u32 parent_tid;
66} lsan_block_context_t;
67
68ALWAYS_INLINE
69void lsan_register_worker_thread(int parent_tid) {
70  if (GetCurrentThread() == kInvalidTid) {
71    u32 tid = ThreadCreate(parent_tid, true);
72    ThreadStart(tid, GetTid());
73    SetCurrentThread(tid);
74  }
75}
76
77// For use by only those functions that allocated the context via
78// alloc_lsan_context().
79extern "C" void lsan_dispatch_call_block_and_release(void *block) {
80  lsan_block_context_t *context = (lsan_block_context_t *)block;
81  VReport(2,
82          "lsan_dispatch_call_block_and_release(): "
83          "context: %p, pthread_self: %p\n",
84          block, pthread_self());
85  lsan_register_worker_thread(context->parent_tid);
86  // Call the original dispatcher for the block.
87  context->func(context->block);
88  lsan_free(context);
89}
90
91}  // namespace __lsan
92
93using namespace __lsan;
94
95// Wrap |ctxt| and |func| into an lsan_block_context_t.
96// The caller retains control of the allocated context.
97extern "C" lsan_block_context_t *alloc_lsan_context(void *ctxt,
98                                                    dispatch_function_t func) {
99  GET_STACK_TRACE_THREAD;
100  lsan_block_context_t *lsan_ctxt =
101      (lsan_block_context_t *)lsan_malloc(sizeof(lsan_block_context_t), stack);
102  lsan_ctxt->block = ctxt;
103  lsan_ctxt->func = func;
104  lsan_ctxt->parent_tid = GetCurrentThread();
105  return lsan_ctxt;
106}
107
108// Define interceptor for dispatch_*_f function with the three most common
109// parameters: dispatch_queue_t, context, dispatch_function_t.
110#define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                        \
111  INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,    \
112              dispatch_function_t func) {                             \
113    lsan_block_context_t *lsan_ctxt = alloc_lsan_context(ctxt, func); \
114    return REAL(dispatch_x_f)(dq, (void *)lsan_ctxt,                  \
115                              lsan_dispatch_call_block_and_release);  \
116  }
117
118INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
119INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
120INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
121
122INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when, dispatch_queue_t dq,
123            void *ctxt, dispatch_function_t func) {
124  lsan_block_context_t *lsan_ctxt = alloc_lsan_context(ctxt, func);
125  return REAL(dispatch_after_f)(when, dq, (void *)lsan_ctxt,
126                                lsan_dispatch_call_block_and_release);
127}
128
129INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
130            dispatch_queue_t dq, void *ctxt, dispatch_function_t func) {
131  lsan_block_context_t *lsan_ctxt = alloc_lsan_context(ctxt, func);
132  REAL(dispatch_group_async_f)
133  (group, dq, (void *)lsan_ctxt, lsan_dispatch_call_block_and_release);
134}
135
136#if !defined(MISSING_BLOCKS_SUPPORT)
137extern "C" {
138void dispatch_async(dispatch_queue_t dq, void (^work)(void));
139void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
140                          void (^work)(void));
141void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
142                    void (^work)(void));
143void dispatch_source_set_cancel_handler(dispatch_source_t ds,
144                                        void (^work)(void));
145void dispatch_source_set_event_handler(dispatch_source_t ds,
146                                       void (^work)(void));
147}
148
149#define GET_LSAN_BLOCK(work)                 \
150  void (^lsan_block)(void);                  \
151  int parent_tid = GetCurrentThread();       \
152  lsan_block = ^(void) {                     \
153    lsan_register_worker_thread(parent_tid); \
154    work();                                  \
155  }
156
157INTERCEPTOR(void, dispatch_async, dispatch_queue_t dq, void (^work)(void)) {
158  GET_LSAN_BLOCK(work);
159  REAL(dispatch_async)(dq, lsan_block);
160}
161
162INTERCEPTOR(void, dispatch_group_async, dispatch_group_t dg,
163            dispatch_queue_t dq, void (^work)(void)) {
164  GET_LSAN_BLOCK(work);
165  REAL(dispatch_group_async)(dg, dq, lsan_block);
166}
167
168INTERCEPTOR(void, dispatch_after, dispatch_time_t when, dispatch_queue_t queue,
169            void (^work)(void)) {
170  GET_LSAN_BLOCK(work);
171  REAL(dispatch_after)(when, queue, lsan_block);
172}
173
174INTERCEPTOR(void, dispatch_source_set_cancel_handler, dispatch_source_t ds,
175            void (^work)(void)) {
176  if (!work) {
177    REAL(dispatch_source_set_cancel_handler)(ds, work);
178    return;
179  }
180  GET_LSAN_BLOCK(work);
181  REAL(dispatch_source_set_cancel_handler)(ds, lsan_block);
182}
183
184INTERCEPTOR(void, dispatch_source_set_event_handler, dispatch_source_t ds,
185            void (^work)(void)) {
186  GET_LSAN_BLOCK(work);
187  REAL(dispatch_source_set_event_handler)(ds, lsan_block);
188}
189#endif
190
191#endif  // SANITIZER_APPLE
192