contrib/compiler-rt/lib/asan/asan_mac.cc

   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 <dlfcn.h>
  28 #include <fcntl.h>
  29 #include <libkern/OSAtomic.h>
  30 #include <mach-o/dyld.h>
  31 #include <mach-o/getsect.h>
  32 #include <mach-o/loader.h>
  33 #include <pthread.h>
  34 #include <stdlib.h>  // for free()
  35 #include <sys/mman.h>
  36 #include <sys/resource.h>
  37 #include <sys/sysctl.h>
  38 #include <sys/ucontext.h>
  39 #include <unistd.h>
  40
  41 // from <crt_externs.h>, but we don't have that file on iOS
  42 extern "C" {
  43   extern char ***_NSGetArgv(void);
  44   extern char ***_NSGetEnviron(void);
  45 }
  46
  47 namespace __asan {
  48
  49 void InitializePlatformInterceptors() {}
  50 void InitializePlatformExceptionHandlers() {}
  51 bool IsSystemHeapAddress (uptr addr) { return false; }
  52
  53 // No-op. Mac does not support static linkage anyway.
  54 void *AsanDoesNotSupportStaticLinkage() {
  55   return 0;
  56 }
  57
  58 uptr FindDynamicShadowStart() {
  59   uptr granularity = GetMmapGranularity();
  60   uptr alignment = 8 * granularity;
  61   uptr left_padding = granularity;
  62   uptr space_size = kHighShadowEnd + left_padding;
  63
  64   uptr largest_gap_found = 0;
  65   uptr max_occupied_addr = 0;
  66   VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
  67   uptr shadow_start =
  68       FindAvailableMemoryRange(space_size, alignment, granularity,
  69                                &largest_gap_found, &max_occupied_addr);
  70   // If the shadow doesn't fit, restrict the address space to make it fit.
  71   if (shadow_start == 0) {
  72     VReport(
  73         2,
  74         "Shadow doesn't fit, largest_gap_found = %p, max_occupied_addr = %p\n",
  75         largest_gap_found, max_occupied_addr);
  76     uptr new_max_vm = RoundDownTo(largest_gap_found << SHADOW_SCALE, alignment);
  77     if (new_max_vm < max_occupied_addr) {
  78       Report("Unable to find a memory range for dynamic shadow.\n");
  79       Report(
  80           "space_size = %p, largest_gap_found = %p, max_occupied_addr = %p, "
  81           "new_max_vm = %p\n",
  82           space_size, largest_gap_found, max_occupied_addr, new_max_vm);
  83       CHECK(0 && "cannot place shadow");
  84     }
  85     RestrictMemoryToMaxAddress(new_max_vm);
  86     kHighMemEnd = new_max_vm - 1;
  87     space_size = kHighShadowEnd + left_padding;
  88     VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
  89     shadow_start = FindAvailableMemoryRange(space_size, alignment, granularity,
  90                                             nullptr, nullptr);
  91     if (shadow_start == 0) {
  92       Report("Unable to find a memory range after restricting VM.\n");
  93       CHECK(0 && "cannot place shadow after restricting vm");
  94     }
  95   }
  96   CHECK_NE((uptr)0, shadow_start);
  97   CHECK(IsAligned(shadow_start, alignment));
  98   return shadow_start;
  99 }
 100
 101 // No-op. Mac does not support static linkage anyway.
 102 void AsanCheckDynamicRTPrereqs() {}
 103
 104 // No-op. Mac does not support static linkage anyway.
 105 void AsanCheckIncompatibleRT() {}
 106
 107 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
 108   // Find the Mach-O header for the image containing the needle
 109   Dl_info info;
 110   int err = dladdr(needle, &info);
 111   if (err == 0) return;
 112
 113 #if __LP64__
 114   const struct mach_header_64 *mh = (struct mach_header_64 *)info.dli_fbase;
 115 #else
 116   const struct mach_header *mh = (struct mach_header *)info.dli_fbase;
 117 #endif
 118
 119   // Look up the __asan_globals section in that image and register its globals
 120   unsigned long size = 0;
 121   __asan_global *globals = (__asan_global *)getsectiondata(
 122       mh,
 123       "__DATA", "__asan_globals",
 124       &size);
 125
 126   if (!globals) return;
 127   if (size % sizeof(__asan_global) != 0) return;
 128   op(globals, size / sizeof(__asan_global));
 129 }
 130
 131 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 132   UNIMPLEMENTED();
 133 }
 134
 135 // Support for the following functions from libdispatch on Mac OS:
 136 //   dispatch_async_f()
 137 //   dispatch_async()
 138 //   dispatch_sync_f()
 139 //   dispatch_sync()
 140 //   dispatch_after_f()
 141 //   dispatch_after()
 142 //   dispatch_group_async_f()
 143 //   dispatch_group_async()
 144 // TODO(glider): libdispatch API contains other functions that we don't support
 145 // yet.
 146 //
 147 // dispatch_sync() and dispatch_sync_f() are synchronous, although chances are
 148 // they can cause jobs to run on a thread different from the current one.
 149 // TODO(glider): if so, we need a test for this (otherwise we should remove
 150 // them).
 151 //
 152 // The following functions use dispatch_barrier_async_f() (which isn't a library
 153 // function but is exported) and are thus supported:
 154 //   dispatch_source_set_cancel_handler_f()
 155 //   dispatch_source_set_cancel_handler()
 156 //   dispatch_source_set_event_handler_f()
 157 //   dispatch_source_set_event_handler()
 158 //
 159 // The reference manual for Grand Central Dispatch is available at
 160 //   http://developer.apple.com/library/mac/#documentation/Performance/Reference/GCD_libdispatch_Ref/Reference/reference.html
 161 // The implementation details are at
 162 //   http://libdispatch.macosforge.org/trac/browser/trunk/src/queue.c
 163
 164 typedef void* dispatch_group_t;
 165 typedef void* dispatch_queue_t;
 166 typedef void* dispatch_source_t;
 167 typedef u64 dispatch_time_t;
 168 typedef void (*dispatch_function_t)(void *block);
 169 typedef void* (*worker_t)(void *block);
 170
 171 // A wrapper for the ObjC blocks used to support libdispatch.
 172 typedef struct {
 173   void *block;
 174   dispatch_function_t func;
 175   u32 parent_tid;
 176 } asan_block_context_t;
 177
 178 ALWAYS_INLINE
 179 void asan_register_worker_thread(int parent_tid, StackTrace *stack) {
 180   AsanThread *t = GetCurrentThread();
 181   if (!t) {
 182     t = AsanThread::Create(/* start_routine */ nullptr, /* arg */ nullptr,
 183                            parent_tid, stack, /* detached */ true);
 184     t->Init();
 185     asanThreadRegistry().StartThread(t->tid(), GetTid(),
 186                                      /* workerthread */ true, 0);
 187     SetCurrentThread(t);
 188   }
 189 }
 190
 191 // For use by only those functions that allocated the context via
 192 // alloc_asan_context().
 193 extern "C"
 194 void asan_dispatch_call_block_and_release(void *block) {
 195   GET_STACK_TRACE_THREAD;
 196   asan_block_context_t *context = (asan_block_context_t*)block;
 197   VReport(2,
 198           "asan_dispatch_call_block_and_release(): "
 199           "context: %p, pthread_self: %p\n",
 200           block, pthread_self());
 201   asan_register_worker_thread(context->parent_tid, &stack);
 202   // Call the original dispatcher for the block.
 203   context->func(context->block);
 204   asan_free(context, &stack, FROM_MALLOC);
 205 }
 206
 207 }  // namespace __asan
 208
 209 using namespace __asan;  // NOLINT
 210
 211 // Wrap |ctxt| and |func| into an asan_block_context_t.
 212 // The caller retains control of the allocated context.
 213 extern "C"
 214 asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
 215                                          BufferedStackTrace *stack) {
 216   asan_block_context_t *asan_ctxt =
 217       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
 218   asan_ctxt->block = ctxt;
 219   asan_ctxt->func = func;
 220   asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
 221   return asan_ctxt;
 222 }
 223
 224 // Define interceptor for dispatch_*_f function with the three most common
 225 // parameters: dispatch_queue_t, context, dispatch_function_t.
 226 #define INTERCEPT_DISPATCH_X_F_3(dispatch_x_f)                                \
 227   INTERCEPTOR(void, dispatch_x_f, dispatch_queue_t dq, void *ctxt,            \
 228                                   dispatch_function_t func) {                 \
 229     GET_STACK_TRACE_THREAD;                                                   \
 230     asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack); \
 231     if (Verbosity() >= 2) {                                     \
 232       Report(#dispatch_x_f "(): context: %p, pthread_self: %p\n",             \
 233              asan_ctxt, pthread_self());                                      \
 234       PRINT_CURRENT_STACK();                                                  \
 235     }                                                                         \
 236     return REAL(dispatch_x_f)(dq, (void*)asan_ctxt,                           \
 237                               asan_dispatch_call_block_and_release);          \
 238   }
 239
 240 INTERCEPT_DISPATCH_X_F_3(dispatch_async_f)
 241 INTERCEPT_DISPATCH_X_F_3(dispatch_sync_f)
 242 INTERCEPT_DISPATCH_X_F_3(dispatch_barrier_async_f)
 243
 244 INTERCEPTOR(void, dispatch_after_f, dispatch_time_t when,
 245                                     dispatch_queue_t dq, void *ctxt,
 246                                     dispatch_function_t func) {
 247   GET_STACK_TRACE_THREAD;
 248   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 249   if (Verbosity() >= 2) {
 250     Report("dispatch_after_f: %p\n", asan_ctxt);
 251     PRINT_CURRENT_STACK();
 252   }
 253   return REAL(dispatch_after_f)(when, dq, (void*)asan_ctxt,
 254                                 asan_dispatch_call_block_and_release);
 255 }
 256
 257 INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
 258                                           dispatch_queue_t dq, void *ctxt,
 259                                           dispatch_function_t func) {
 260   GET_STACK_TRACE_THREAD;
 261   asan_block_context_t *asan_ctxt = alloc_asan_context(ctxt, func, &stack);
 262   if (Verbosity() >= 2) {
 263     Report("dispatch_group_async_f(): context: %p, pthread_self: %p\n",
 264            asan_ctxt, pthread_self());
 265     PRINT_CURRENT_STACK();
 266   }
 267   REAL(dispatch_group_async_f)(group, dq, (void*)asan_ctxt,
 268                                asan_dispatch_call_block_and_release);
 269 }
 270
 271 #if !defined(MISSING_BLOCKS_SUPPORT)
 272 extern "C" {
 273 void dispatch_async(dispatch_queue_t dq, void(^work)(void));
 274 void dispatch_group_async(dispatch_group_t dg, dispatch_queue_t dq,
 275                           void(^work)(void));
 276 void dispatch_after(dispatch_time_t when, dispatch_queue_t queue,
 277                     void(^work)(void));
 278 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
 279                                         void(^work)(void));
 280 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
 281 }
 282
 283 #define GET_ASAN_BLOCK(work) \
 284   void (^asan_block)(void);  \
 285   int parent_tid = GetCurrentTidOrInvalid(); \
 286   asan_block = ^(void) { \
 287     GET_STACK_TRACE_THREAD; \
 288     asan_register_worker_thread(parent_tid, &stack); \
 289     work(); \
 290   }
 291
 292 INTERCEPTOR(void, dispatch_async,
 293             dispatch_queue_t dq, void(^work)(void)) {
 294   ENABLE_FRAME_POINTER;
 295   GET_ASAN_BLOCK(work);
 296   REAL(dispatch_async)(dq, asan_block);
 297 }
 298
 299 INTERCEPTOR(void, dispatch_group_async,
 300             dispatch_group_t dg, dispatch_queue_t dq, void(^work)(void)) {
 301   ENABLE_FRAME_POINTER;
 302   GET_ASAN_BLOCK(work);
 303   REAL(dispatch_group_async)(dg, dq, asan_block);
 304 }
 305
 306 INTERCEPTOR(void, dispatch_after,
 307             dispatch_time_t when, dispatch_queue_t queue, void(^work)(void)) {
 308   ENABLE_FRAME_POINTER;
 309   GET_ASAN_BLOCK(work);
 310   REAL(dispatch_after)(when, queue, asan_block);
 311 }
 312
 313 INTERCEPTOR(void, dispatch_source_set_cancel_handler,
 314             dispatch_source_t ds, void(^work)(void)) {
 315   if (!work) {
 316     REAL(dispatch_source_set_cancel_handler)(ds, work);
 317     return;
 318   }
 319   ENABLE_FRAME_POINTER;
 320   GET_ASAN_BLOCK(work);
 321   REAL(dispatch_source_set_cancel_handler)(ds, asan_block);
 322 }
 323
 324 INTERCEPTOR(void, dispatch_source_set_event_handler,
 325             dispatch_source_t ds, void(^work)(void)) {
 326   ENABLE_FRAME_POINTER;
 327   GET_ASAN_BLOCK(work);
 328   REAL(dispatch_source_set_event_handler)(ds, asan_block);
 329 }
 330 #endif
 331
 332 #endif  // SANITIZER_MAC