libsanitizer/tsan/tsan_platform_mac.cc

   1 //===-- tsan_platform_mac.cc ----------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of ThreadSanitizer (TSan), a race detector.
   9 //
  10 // Mac-specific code.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_common/sanitizer_platform.h"
  14 #if SANITIZER_MAC
  15
  16 #include "sanitizer_common/sanitizer_atomic.h"
  17 #include "sanitizer_common/sanitizer_common.h"
  18 #include "sanitizer_common/sanitizer_libc.h"
  19 #include "sanitizer_common/sanitizer_posix.h"
  20 #include "sanitizer_common/sanitizer_procmaps.h"
  21 #include "tsan_platform.h"
  22 #include "tsan_rtl.h"
  23 #include "tsan_flags.h"
  24
  25 #include <pthread.h>
  26 #include <signal.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <stdarg.h>
  31 #include <sys/mman.h>
  32 #include <sys/syscall.h>
  33 #include <sys/time.h>
  34 #include <sys/types.h>
  35 #include <sys/resource.h>
  36 #include <sys/stat.h>
  37 #include <unistd.h>
  38 #include <errno.h>
  39 #include <sched.h>
  40
  41 namespace __tsan {
  42
  43 #ifndef SANITIZER_GO
  44 static void *SignalSafeGetOrAllocate(uptr *dst, uptr size) {
  45   atomic_uintptr_t *a = (atomic_uintptr_t *)dst;
  46   void *val = (void *)atomic_load_relaxed(a);
  47   atomic_signal_fence(memory_order_acquire);  // Turns the previous load into
  48                                               // acquire wrt signals.
  49   if (UNLIKELY(val == nullptr)) {
  50     val = (void *)internal_mmap(nullptr, size, PROT_READ | PROT_WRITE,
  51                                 MAP_PRIVATE | MAP_ANON, -1, 0);
  52     CHECK(val);
  53     void *cmp = nullptr;
  54     if (!atomic_compare_exchange_strong(a, (uintptr_t *)&cmp, (uintptr_t)val,
  55                                         memory_order_acq_rel)) {
  56       internal_munmap(val, size);
  57       val = cmp;
  58     }
  59   }
  60   return val;
  61 }
  62
  63 // On OS X, accessing TLVs via __thread or manually by using pthread_key_* is
  64 // problematic, because there are several places where interceptors are called
  65 // when TLVs are not accessible (early process startup, thread cleanup, ...).
  66 // The following provides a "poor man's TLV" implementation, where we use the
  67 // shadow memory of the pointer returned by pthread_self() to store a pointer to
  68 // the ThreadState object. The main thread's ThreadState pointer is stored
  69 // separately in a static variable, because we need to access it even before the
  70 // shadow memory is set up.
  71 static uptr main_thread_identity = 0;
  72 static ThreadState *main_thread_state = nullptr;
  73
  74 ThreadState *cur_thread() {
  75   ThreadState **fake_tls;
  76   uptr thread_identity = (uptr)pthread_self();
  77   if (thread_identity == main_thread_identity || main_thread_identity == 0) {
  78     fake_tls = &main_thread_state;
  79   } else {
  80     fake_tls = (ThreadState **)MemToShadow(thread_identity);
  81   }
  82   ThreadState *thr = (ThreadState *)SignalSafeGetOrAllocate(
  83       (uptr *)fake_tls, sizeof(ThreadState));
  84   return thr;
  85 }
  86
  87 // TODO(kuba.brecka): This is not async-signal-safe. In particular, we call
  88 // munmap first and then clear `fake_tls`; if we receive a signal in between,
  89 // handler will try to access the unmapped ThreadState.
  90 void cur_thread_finalize() {
  91   uptr thread_identity = (uptr)pthread_self();
  92   CHECK_NE(thread_identity, main_thread_identity);
  93   ThreadState **fake_tls = (ThreadState **)MemToShadow(thread_identity);
  94   internal_munmap(*fake_tls, sizeof(ThreadState));
  95   *fake_tls = nullptr;
  96 }
  97 #endif
  98
  99 uptr GetShadowMemoryConsumption() {
 100   return 0;
 101 }
 102
 103 void FlushShadowMemory() {
 104 }
 105
 106 void WriteMemoryProfile(char *buf, uptr buf_size, uptr nthread, uptr nlive) {
 107 }
 108
 109 #ifndef SANITIZER_GO
 110 void InitializeShadowMemoryPlatform() { }
 111
 112 // On OS X, GCD worker threads are created without a call to pthread_create. We
 113 // need to properly register these threads with ThreadCreate and ThreadStart.
 114 // These threads don't have a parent thread, as they are created "spuriously".
 115 // We're using a libpthread API that notifies us about a newly created thread.
 116 // The `thread == pthread_self()` check indicates this is actually a worker
 117 // thread. If it's just a regular thread, this hook is called on the parent
 118 // thread.
 119 typedef void (*pthread_introspection_hook_t)(unsigned int event,
 120                                              pthread_t thread, void *addr,
 121                                              size_t size);
 122 extern "C" pthread_introspection_hook_t pthread_introspection_hook_install(
 123     pthread_introspection_hook_t hook);
 124 static const uptr PTHREAD_INTROSPECTION_THREAD_CREATE = 1;
 125 static const uptr PTHREAD_INTROSPECTION_THREAD_DESTROY = 4;
 126 static pthread_introspection_hook_t prev_pthread_introspection_hook;
 127 static void my_pthread_introspection_hook(unsigned int event, pthread_t thread,
 128                                           void *addr, size_t size) {
 129   if (event == PTHREAD_INTROSPECTION_THREAD_CREATE) {
 130     if (thread == pthread_self()) {
 131       // The current thread is a newly created GCD worker thread.
 132       ThreadState *parent_thread_state = nullptr;  // No parent.
 133       int tid = ThreadCreate(parent_thread_state, 0, (uptr)thread, true);
 134       CHECK_NE(tid, 0);
 135       ThreadState *thr = cur_thread();
 136       ThreadStart(thr, tid, GetTid());
 137     }
 138   } else if (event == PTHREAD_INTROSPECTION_THREAD_DESTROY) {
 139     ThreadState *thr = cur_thread();
 140     if (thr->tctx && thr->tctx->parent_tid == kInvalidTid) {
 141       DestroyThreadState();
 142     }
 143   }
 144
 145   if (prev_pthread_introspection_hook != nullptr)
 146     prev_pthread_introspection_hook(event, thread, addr, size);
 147 }
 148 #endif
 149
 150 void InitializePlatform() {
 151   DisableCoreDumperIfNecessary();
 152 #ifndef SANITIZER_GO
 153   CheckAndProtect();
 154
 155   CHECK_EQ(main_thread_identity, 0);
 156   main_thread_identity = (uptr)pthread_self();
 157
 158   prev_pthread_introspection_hook =
 159       pthread_introspection_hook_install(&my_pthread_introspection_hook);
 160 #endif
 161 }
 162
 163 #ifndef SANITIZER_GO
 164 // Note: this function runs with async signals enabled,
 165 // so it must not touch any tsan state.
 166 int call_pthread_cancel_with_cleanup(int(*fn)(void *c, void *m,
 167     void *abstime), void *c, void *m, void *abstime,
 168     void(*cleanup)(void *arg), void *arg) {
 169   // pthread_cleanup_push/pop are hardcore macros mess.
 170   // We can't intercept nor call them w/o including pthread.h.
 171   int res;
 172   pthread_cleanup_push(cleanup, arg);
 173   res = fn(c, m, abstime);
 174   pthread_cleanup_pop(0);
 175   return res;
 176 }
 177 #endif
 178
 179 bool IsGlobalVar(uptr addr) {
 180   return false;
 181 }
 182
 183 }  // namespace __tsan
 184
 185 #endif  // SANITIZER_MAC