1//===-- sanitizer_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 shared between various sanitizers' runtime libraries and
10// implements OSX-specific functions.
11//===----------------------------------------------------------------------===//
12
13#include "sanitizer_platform.h"
14#if SANITIZER_APPLE
15#include "sanitizer_mac.h"
16#include "interception/interception.h"
17
18// Use 64-bit inodes in file operations. ASan does not support OS X 10.5, so
19// the clients will most certainly use 64-bit ones as well.
20#ifndef _DARWIN_USE_64_BIT_INODE
21#define _DARWIN_USE_64_BIT_INODE 1
22#endif
23#include <stdio.h>
24
25#include "sanitizer_common.h"
26#include "sanitizer_file.h"
27#include "sanitizer_flags.h"
28#include "sanitizer_interface_internal.h"
29#include "sanitizer_internal_defs.h"
30#include "sanitizer_libc.h"
31#include "sanitizer_platform_limits_posix.h"
32#include "sanitizer_procmaps.h"
33#include "sanitizer_ptrauth.h"
34
35#if !SANITIZER_IOS
36#include <crt_externs.h>  // for _NSGetEnviron
37#else
38extern char **environ;
39#endif
40
41#if defined(__has_include) && __has_include(<os/trace.h>)
42#define SANITIZER_OS_TRACE 1
43#include <os/trace.h>
44#else
45#define SANITIZER_OS_TRACE 0
46#endif
47
48// import new crash reporting api
49#if defined(__has_include) && __has_include(<CrashReporterClient.h>)
50#define HAVE_CRASHREPORTERCLIENT_H 1
51#include <CrashReporterClient.h>
52#else
53#define HAVE_CRASHREPORTERCLIENT_H 0
54#endif
55
56#if !SANITIZER_IOS
57#include <crt_externs.h>  // for _NSGetArgv and _NSGetEnviron
58#else
59extern "C" {
60  extern char ***_NSGetArgv(void);
61}
62#endif
63
64#include <asl.h>
65#include <dlfcn.h>  // for dladdr()
66#include <errno.h>
67#include <fcntl.h>
68#include <libkern/OSAtomic.h>
69#include <mach-o/dyld.h>
70#include <mach/mach.h>
71#include <mach/mach_time.h>
72#include <mach/vm_statistics.h>
73#include <malloc/malloc.h>
74#include <os/log.h>
75#include <pthread.h>
76#include <pthread/introspection.h>
77#include <sched.h>
78#include <signal.h>
79#include <spawn.h>
80#include <stdlib.h>
81#include <sys/ioctl.h>
82#include <sys/mman.h>
83#include <sys/resource.h>
84#include <sys/stat.h>
85#include <sys/sysctl.h>
86#include <sys/types.h>
87#include <sys/wait.h>
88#include <unistd.h>
89#include <util.h>
90
91// From <crt_externs.h>, but we don't have that file on iOS.
92extern "C" {
93  extern char ***_NSGetArgv(void);
94  extern char ***_NSGetEnviron(void);
95}
96
97// From <mach/mach_vm.h>, but we don't have that file on iOS.
98extern "C" {
99  extern kern_return_t mach_vm_region_recurse(
100    vm_map_t target_task,
101    mach_vm_address_t *address,
102    mach_vm_size_t *size,
103    natural_t *nesting_depth,
104    vm_region_recurse_info_t info,
105    mach_msg_type_number_t *infoCnt);
106}
107
108namespace __sanitizer {
109
110#include "sanitizer_syscall_generic.inc"
111
112// Direct syscalls, don't call libmalloc hooks (but not available on 10.6).
113extern "C" void *__mmap(void *addr, size_t len, int prot, int flags, int fildes,
114                        off_t off) SANITIZER_WEAK_ATTRIBUTE;
115extern "C" int __munmap(void *, size_t) SANITIZER_WEAK_ATTRIBUTE;
116
117// ---------------------- sanitizer_libc.h
118
119// From <mach/vm_statistics.h>, but not on older OSs.
120#ifndef VM_MEMORY_SANITIZER
121#define VM_MEMORY_SANITIZER 99
122#endif
123
124// XNU on Darwin provides a mmap flag that optimizes allocation/deallocation of
125// giant memory regions (i.e. shadow memory regions).
126#define kXnuFastMmapFd 0x4
127static size_t kXnuFastMmapThreshold = 2 << 30; // 2 GB
128static bool use_xnu_fast_mmap = false;
129
130uptr internal_mmap(void *addr, size_t length, int prot, int flags,
131                   int fd, u64 offset) {
132  if (fd == -1) {
133    fd = VM_MAKE_TAG(VM_MEMORY_SANITIZER);
134    if (length >= kXnuFastMmapThreshold) {
135      if (use_xnu_fast_mmap) fd |= kXnuFastMmapFd;
136    }
137  }
138  if (&__mmap) return (uptr)__mmap(addr, length, prot, flags, fd, offset);
139  return (uptr)mmap(addr, length, prot, flags, fd, offset);
140}
141
142uptr internal_munmap(void *addr, uptr length) {
143  if (&__munmap) return __munmap(addr, length);
144  return munmap(addr, length);
145}
146
147uptr internal_mremap(void *old_address, uptr old_size, uptr new_size, int flags,
148                     void *new_address) {
149  CHECK(false && "internal_mremap is unimplemented on Mac");
150  return 0;
151}
152
153int internal_mprotect(void *addr, uptr length, int prot) {
154  return mprotect(addr, length, prot);
155}
156
157int internal_madvise(uptr addr, uptr length, int advice) {
158  return madvise((void *)addr, length, advice);
159}
160
161uptr internal_close(fd_t fd) {
162  return close(fd);
163}
164
165uptr internal_open(const char *filename, int flags) {
166  return open(filename, flags);
167}
168
169uptr internal_open(const char *filename, int flags, u32 mode) {
170  return open(filename, flags, mode);
171}
172
173uptr internal_read(fd_t fd, void *buf, uptr count) {
174  return read(fd, buf, count);
175}
176
177uptr internal_write(fd_t fd, const void *buf, uptr count) {
178  return write(fd, buf, count);
179}
180
181uptr internal_stat(const char *path, void *buf) {
182  return stat(path, (struct stat *)buf);
183}
184
185uptr internal_lstat(const char *path, void *buf) {
186  return lstat(path, (struct stat *)buf);
187}
188
189uptr internal_fstat(fd_t fd, void *buf) {
190  return fstat(fd, (struct stat *)buf);
191}
192
193uptr internal_filesize(fd_t fd) {
194  struct stat st;
195  if (internal_fstat(fd, &st))
196    return -1;
197  return (uptr)st.st_size;
198}
199
200uptr internal_dup(int oldfd) {
201  return dup(oldfd);
202}
203
204uptr internal_dup2(int oldfd, int newfd) {
205  return dup2(oldfd, newfd);
206}
207
208uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
209  return readlink(path, buf, bufsize);
210}
211
212uptr internal_unlink(const char *path) {
213  return unlink(path);
214}
215
216uptr internal_sched_yield() {
217  return sched_yield();
218}
219
220void internal__exit(int exitcode) {
221  _exit(exitcode);
222}
223
224void internal_usleep(u64 useconds) { usleep(useconds); }
225
226uptr internal_getpid() {
227  return getpid();
228}
229
230int internal_dlinfo(void *handle, int request, void *p) {
231  UNIMPLEMENTED();
232}
233
234int internal_sigaction(int signum, const void *act, void *oldact) {
235  return sigaction(signum,
236                   (const struct sigaction *)act, (struct sigaction *)oldact);
237}
238
239void internal_sigfillset(__sanitizer_sigset_t *set) { sigfillset(set); }
240
241uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
242                          __sanitizer_sigset_t *oldset) {
243  // Don't use sigprocmask here, because it affects all threads.
244  return pthread_sigmask(how, set, oldset);
245}
246
247// Doesn't call pthread_atfork() handlers (but not available on 10.6).
248extern "C" pid_t __fork(void) SANITIZER_WEAK_ATTRIBUTE;
249
250int internal_fork() {
251  if (&__fork)
252    return __fork();
253  return fork();
254}
255
256int internal_sysctl(const int *name, unsigned int namelen, void *oldp,
257                    uptr *oldlenp, const void *newp, uptr newlen) {
258  return sysctl(const_cast<int *>(name), namelen, oldp, (size_t *)oldlenp,
259                const_cast<void *>(newp), (size_t)newlen);
260}
261
262int internal_sysctlbyname(const char *sname, void *oldp, uptr *oldlenp,
263                          const void *newp, uptr newlen) {
264  return sysctlbyname(sname, oldp, (size_t *)oldlenp, const_cast<void *>(newp),
265                      (size_t)newlen);
266}
267
268static fd_t internal_spawn_impl(const char *argv[], const char *envp[],
269                                pid_t *pid) {
270  fd_t primary_fd = kInvalidFd;
271  fd_t secondary_fd = kInvalidFd;
272
273  auto fd_closer = at_scope_exit([&] {
274    internal_close(primary_fd);
275    internal_close(secondary_fd);
276  });
277
278  // We need a new pseudoterminal to avoid buffering problems. The 'atos' tool
279  // in particular detects when it's talking to a pipe and forgets to flush the
280  // output stream after sending a response.
281  primary_fd = posix_openpt(O_RDWR);
282  if (primary_fd == kInvalidFd)
283    return kInvalidFd;
284
285  int res = grantpt(primary_fd) || unlockpt(primary_fd);
286  if (res != 0) return kInvalidFd;
287
288  // Use TIOCPTYGNAME instead of ptsname() to avoid threading problems.
289  char secondary_pty_name[128];
290  res = ioctl(primary_fd, TIOCPTYGNAME, secondary_pty_name);
291  if (res == -1) return kInvalidFd;
292
293  secondary_fd = internal_open(secondary_pty_name, O_RDWR);
294  if (secondary_fd == kInvalidFd)
295    return kInvalidFd;
296
297  // File descriptor actions
298  posix_spawn_file_actions_t acts;
299  res = posix_spawn_file_actions_init(&acts);
300  if (res != 0) return kInvalidFd;
301
302  auto acts_cleanup = at_scope_exit([&] {
303    posix_spawn_file_actions_destroy(&acts);
304  });
305
306  res = posix_spawn_file_actions_adddup2(&acts, secondary_fd, STDIN_FILENO) ||
307        posix_spawn_file_actions_adddup2(&acts, secondary_fd, STDOUT_FILENO) ||
308        posix_spawn_file_actions_addclose(&acts, secondary_fd);
309  if (res != 0) return kInvalidFd;
310
311  // Spawn attributes
312  posix_spawnattr_t attrs;
313  res = posix_spawnattr_init(&attrs);
314  if (res != 0) return kInvalidFd;
315
316  auto attrs_cleanup  = at_scope_exit([&] {
317    posix_spawnattr_destroy(&attrs);
318  });
319
320  // In the spawned process, close all file descriptors that are not explicitly
321  // described by the file actions object. This is Darwin-specific extension.
322  res = posix_spawnattr_setflags(&attrs, POSIX_SPAWN_CLOEXEC_DEFAULT);
323  if (res != 0) return kInvalidFd;
324
325  // posix_spawn
326  char **argv_casted = const_cast<char **>(argv);
327  char **envp_casted = const_cast<char **>(envp);
328  res = posix_spawn(pid, argv[0], &acts, &attrs, argv_casted, envp_casted);
329  if (res != 0) return kInvalidFd;
330
331  // Disable echo in the new terminal, disable CR.
332  struct termios termflags;
333  tcgetattr(primary_fd, &termflags);
334  termflags.c_oflag &= ~ONLCR;
335  termflags.c_lflag &= ~ECHO;
336  tcsetattr(primary_fd, TCSANOW, &termflags);
337
338  // On success, do not close primary_fd on scope exit.
339  fd_t fd = primary_fd;
340  primary_fd = kInvalidFd;
341
342  return fd;
343}
344
345fd_t internal_spawn(const char *argv[], const char *envp[], pid_t *pid) {
346  // The client program may close its stdin and/or stdout and/or stderr thus
347  // allowing open/posix_openpt to reuse file descriptors 0, 1 or 2. In this
348  // case the communication is broken if either the parent or the child tries to
349  // close or duplicate these descriptors. We temporarily reserve these
350  // descriptors here to prevent this.
351  fd_t low_fds[3];
352  size_t count = 0;
353
354  for (; count < 3; count++) {
355    low_fds[count] = posix_openpt(O_RDWR);
356    if (low_fds[count] >= STDERR_FILENO)
357      break;
358  }
359
360  fd_t fd = internal_spawn_impl(argv, envp, pid);
361
362  for (; count > 0; count--) {
363    internal_close(low_fds[count]);
364  }
365
366  return fd;
367}
368
369uptr internal_rename(const char *oldpath, const char *newpath) {
370  return rename(oldpath, newpath);
371}
372
373uptr internal_ftruncate(fd_t fd, uptr size) {
374  return ftruncate(fd, size);
375}
376
377uptr internal_execve(const char *filename, char *const argv[],
378                     char *const envp[]) {
379  return execve(filename, argv, envp);
380}
381
382uptr internal_waitpid(int pid, int *status, int options) {
383  return waitpid(pid, status, options);
384}
385
386// ----------------- sanitizer_common.h
387bool FileExists(const char *filename) {
388  if (ShouldMockFailureToOpen(filename))
389    return false;
390  struct stat st;
391  if (stat(filename, &st))
392    return false;
393  // Sanity check: filename is a regular file.
394  return S_ISREG(st.st_mode);
395}
396
397bool DirExists(const char *path) {
398  struct stat st;
399  if (stat(path, &st))
400    return false;
401  return S_ISDIR(st.st_mode);
402}
403
404tid_t GetTid() {
405  tid_t tid;
406  pthread_threadid_np(nullptr, &tid);
407  return tid;
408}
409
410void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
411                                uptr *stack_bottom) {
412  CHECK(stack_top);
413  CHECK(stack_bottom);
414  uptr stacksize = pthread_get_stacksize_np(pthread_self());
415  // pthread_get_stacksize_np() returns an incorrect stack size for the main
416  // thread on Mavericks. See
417  // https://github.com/google/sanitizers/issues/261
418  if ((GetMacosAlignedVersion() >= MacosVersion(10, 9)) && at_initialization &&
419      stacksize == (1 << 19))  {
420    struct rlimit rl;
421    CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
422    // Most often rl.rlim_cur will be the desired 8M.
423    if (rl.rlim_cur < kMaxThreadStackSize) {
424      stacksize = rl.rlim_cur;
425    } else {
426      stacksize = kMaxThreadStackSize;
427    }
428  }
429  void *stackaddr = pthread_get_stackaddr_np(pthread_self());
430  *stack_top = (uptr)stackaddr;
431  *stack_bottom = *stack_top - stacksize;
432}
433
434char **GetEnviron() {
435#if !SANITIZER_IOS
436  char ***env_ptr = _NSGetEnviron();
437  if (!env_ptr) {
438    Report("_NSGetEnviron() returned NULL. Please make sure __asan_init() is "
439           "called after libSystem_initializer().\n");
440    CHECK(env_ptr);
441  }
442  char **environ = *env_ptr;
443#endif
444  CHECK(environ);
445  return environ;
446}
447
448const char *GetEnv(const char *name) {
449  char **env = GetEnviron();
450  uptr name_len = internal_strlen(name);
451  while (*env != 0) {
452    uptr len = internal_strlen(*env);
453    if (len > name_len) {
454      const char *p = *env;
455      if (!internal_memcmp(p, name, name_len) &&
456          p[name_len] == '=') {  // Match.
457        return *env + name_len + 1;  // String starting after =.
458      }
459    }
460    env++;
461  }
462  return 0;
463}
464
465uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
466  CHECK_LE(kMaxPathLength, buf_len);
467
468  // On OS X the executable path is saved to the stack by dyld. Reading it
469  // from there is much faster than calling dladdr, especially for large
470  // binaries with symbols.
471  InternalMmapVector<char> exe_path(kMaxPathLength);
472  uint32_t size = exe_path.size();
473  if (_NSGetExecutablePath(exe_path.data(), &size) == 0 &&
474      realpath(exe_path.data(), buf) != 0) {
475    return internal_strlen(buf);
476  }
477  return 0;
478}
479
480uptr ReadLongProcessName(/*out*/char *buf, uptr buf_len) {
481  return ReadBinaryName(buf, buf_len);
482}
483
484void ReExec() {
485  UNIMPLEMENTED();
486}
487
488void CheckASLR() {
489  // Do nothing
490}
491
492void CheckMPROTECT() {
493  // Do nothing
494}
495
496uptr GetPageSize() {
497  return sysconf(_SC_PAGESIZE);
498}
499
500extern "C" unsigned malloc_num_zones;
501extern "C" malloc_zone_t **malloc_zones;
502malloc_zone_t sanitizer_zone;
503
504// We need to make sure that sanitizer_zone is registered as malloc_zones[0]. If
505// libmalloc tries to set up a different zone as malloc_zones[0], it will call
506// mprotect(malloc_zones, ..., PROT_READ).  This interceptor will catch that and
507// make sure we are still the first (default) zone.
508void MprotectMallocZones(void *addr, int prot) {
509  if (addr == malloc_zones && prot == PROT_READ) {
510    if (malloc_num_zones > 1 && malloc_zones[0] != &sanitizer_zone) {
511      for (unsigned i = 1; i < malloc_num_zones; i++) {
512        if (malloc_zones[i] == &sanitizer_zone) {
513          // Swap malloc_zones[0] and malloc_zones[i].
514          malloc_zones[i] = malloc_zones[0];
515          malloc_zones[0] = &sanitizer_zone;
516          break;
517        }
518      }
519    }
520  }
521}
522
523void FutexWait(atomic_uint32_t *p, u32 cmp) {
524  // FIXME: implement actual blocking.
525  sched_yield();
526}
527
528void FutexWake(atomic_uint32_t *p, u32 count) {}
529
530u64 NanoTime() {
531  timeval tv;
532  internal_memset(&tv, 0, sizeof(tv));
533  gettimeofday(&tv, 0);
534  return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
535}
536
537// This needs to be called during initialization to avoid being racy.
538u64 MonotonicNanoTime() {
539  static mach_timebase_info_data_t timebase_info;
540  if (timebase_info.denom == 0) mach_timebase_info(&timebase_info);
541  return (mach_absolute_time() * timebase_info.numer) / timebase_info.denom;
542}
543
544uptr GetTlsSize() {
545  return 0;
546}
547
548void InitTlsSize() {
549}
550
551uptr TlsBaseAddr() {
552  uptr segbase = 0;
553#if defined(__x86_64__)
554  asm("movq %%gs:0,%0" : "=r"(segbase));
555#elif defined(__i386__)
556  asm("movl %%gs:0,%0" : "=r"(segbase));
557#elif defined(__aarch64__)
558  asm("mrs %x0, tpidrro_el0" : "=r"(segbase));
559  segbase &= 0x07ul;  // clearing lower bits, cpu id stored there
560#endif
561  return segbase;
562}
563
564// The size of the tls on darwin does not appear to be well documented,
565// however the vm memory map suggests that it is 1024 uptrs in size,
566// with a size of 0x2000 bytes on x86_64 and 0x1000 bytes on i386.
567uptr TlsSize() {
568#if defined(__x86_64__) || defined(__i386__)
569  return 1024 * sizeof(uptr);
570#else
571  return 0;
572#endif
573}
574
575void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
576                          uptr *tls_addr, uptr *tls_size) {
577#if !SANITIZER_GO
578  uptr stack_top, stack_bottom;
579  GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
580  *stk_addr = stack_bottom;
581  *stk_size = stack_top - stack_bottom;
582  *tls_addr = TlsBaseAddr();
583  *tls_size = TlsSize();
584#else
585  *stk_addr = 0;
586  *stk_size = 0;
587  *tls_addr = 0;
588  *tls_size = 0;
589#endif
590}
591
592void ListOfModules::init() {
593  clearOrInit();
594  MemoryMappingLayout memory_mapping(false);
595  memory_mapping.DumpListOfModules(&modules_);
596}
597
598void ListOfModules::fallbackInit() { clear(); }
599
600static HandleSignalMode GetHandleSignalModeImpl(int signum) {
601  switch (signum) {
602    case SIGABRT:
603      return common_flags()->handle_abort;
604    case SIGILL:
605      return common_flags()->handle_sigill;
606    case SIGTRAP:
607      return common_flags()->handle_sigtrap;
608    case SIGFPE:
609      return common_flags()->handle_sigfpe;
610    case SIGSEGV:
611      return common_flags()->handle_segv;
612    case SIGBUS:
613      return common_flags()->handle_sigbus;
614  }
615  return kHandleSignalNo;
616}
617
618HandleSignalMode GetHandleSignalMode(int signum) {
619  // Handling fatal signals on watchOS and tvOS devices is disallowed.
620  if ((SANITIZER_WATCHOS || SANITIZER_TVOS) && !(SANITIZER_IOSSIM))
621    return kHandleSignalNo;
622  HandleSignalMode result = GetHandleSignalModeImpl(signum);
623  if (result == kHandleSignalYes && !common_flags()->allow_user_segv_handler)
624    return kHandleSignalExclusive;
625  return result;
626}
627
628// Offset example:
629// XNU 17 -- macOS 10.13 -- iOS 11 -- tvOS 11 -- watchOS 4
630constexpr u16 GetOSMajorKernelOffset() {
631  if (TARGET_OS_OSX) return 4;
632  if (TARGET_OS_IOS || TARGET_OS_TV) return 6;
633  if (TARGET_OS_WATCH) return 13;
634}
635
636using VersStr = char[64];
637
638static uptr ApproximateOSVersionViaKernelVersion(VersStr vers) {
639  u16 kernel_major = GetDarwinKernelVersion().major;
640  u16 offset = GetOSMajorKernelOffset();
641  CHECK_GE(kernel_major, offset);
642  u16 os_major = kernel_major - offset;
643
644  const char *format = "%d.0";
645  if (TARGET_OS_OSX) {
646    if (os_major >= 16) {  // macOS 11+
647      os_major -= 5;
648    } else {  // macOS 10.15 and below
649      format = "10.%d";
650    }
651  }
652  return internal_snprintf(vers, sizeof(VersStr), format, os_major);
653}
654
655static void GetOSVersion(VersStr vers) {
656  uptr len = sizeof(VersStr);
657  if (SANITIZER_IOSSIM) {
658    const char *vers_env = GetEnv("SIMULATOR_RUNTIME_VERSION");
659    if (!vers_env) {
660      Report("ERROR: Running in simulator but SIMULATOR_RUNTIME_VERSION env "
661          "var is not set.\n");
662      Die();
663    }
664    len = internal_strlcpy(vers, vers_env, len);
665  } else {
666    int res =
667        internal_sysctlbyname("kern.osproductversion", vers, &len, nullptr, 0);
668
669    // XNU 17 (macOS 10.13) and below do not provide the sysctl
670    // `kern.osproductversion` entry (res != 0).
671    bool no_os_version = res != 0;
672
673    // For launchd, sanitizer initialization runs before sysctl is setup
674    // (res == 0 && len != strlen(vers), vers is not a valid version).  However,
675    // the kernel version `kern.osrelease` is available.
676    bool launchd = (res == 0 && internal_strlen(vers) < 3);
677    if (launchd) CHECK_EQ(internal_getpid(), 1);
678
679    if (no_os_version || launchd) {
680      len = ApproximateOSVersionViaKernelVersion(vers);
681    }
682  }
683  CHECK_LT(len, sizeof(VersStr));
684}
685
686void ParseVersion(const char *vers, u16 *major, u16 *minor) {
687  // Format: <major>.<minor>[.<patch>]\0
688  CHECK_GE(internal_strlen(vers), 3);
689  const char *p = vers;
690  *major = internal_simple_strtoll(p, &p, /*base=*/10);
691  CHECK_EQ(*p, '.');
692  p += 1;
693  *minor = internal_simple_strtoll(p, &p, /*base=*/10);
694}
695
696// Aligned versions example:
697// macOS 10.15 -- iOS 13 -- tvOS 13 -- watchOS 6
698static void MapToMacos(u16 *major, u16 *minor) {
699  if (TARGET_OS_OSX)
700    return;
701
702  if (TARGET_OS_IOS || TARGET_OS_TV)
703    *major += 2;
704  else if (TARGET_OS_WATCH)
705    *major += 9;
706  else
707    UNREACHABLE("unsupported platform");
708
709  if (*major >= 16) {  // macOS 11+
710    *major -= 5;
711  } else {  // macOS 10.15 and below
712    *minor = *major;
713    *major = 10;
714  }
715}
716
717static MacosVersion GetMacosAlignedVersionInternal() {
718  VersStr vers = {};
719  GetOSVersion(vers);
720
721  u16 major, minor;
722  ParseVersion(vers, &major, &minor);
723  MapToMacos(&major, &minor);
724
725  return MacosVersion(major, minor);
726}
727
728static_assert(sizeof(MacosVersion) == sizeof(atomic_uint32_t::Type),
729              "MacosVersion cache size");
730static atomic_uint32_t cached_macos_version;
731
732MacosVersion GetMacosAlignedVersion() {
733  atomic_uint32_t::Type result =
734      atomic_load(&cached_macos_version, memory_order_acquire);
735  if (!result) {
736    MacosVersion version = GetMacosAlignedVersionInternal();
737    result = *reinterpret_cast<atomic_uint32_t::Type *>(&version);
738    atomic_store(&cached_macos_version, result, memory_order_release);
739  }
740  return *reinterpret_cast<MacosVersion *>(&result);
741}
742
743DarwinKernelVersion GetDarwinKernelVersion() {
744  VersStr vers = {};
745  uptr len = sizeof(VersStr);
746  int res = internal_sysctlbyname("kern.osrelease", vers, &len, nullptr, 0);
747  CHECK_EQ(res, 0);
748  CHECK_LT(len, sizeof(VersStr));
749
750  u16 major, minor;
751  ParseVersion(vers, &major, &minor);
752
753  return DarwinKernelVersion(major, minor);
754}
755
756uptr GetRSS() {
757  struct task_basic_info info;
758  unsigned count = TASK_BASIC_INFO_COUNT;
759  kern_return_t result =
760      task_info(mach_task_self(), TASK_BASIC_INFO, (task_info_t)&info, &count);
761  if (UNLIKELY(result != KERN_SUCCESS)) {
762    Report("Cannot get task info. Error: %d\n", result);
763    Die();
764  }
765  return info.resident_size;
766}
767
768void *internal_start_thread(void *(*func)(void *arg), void *arg) {
769  // Start the thread with signals blocked, otherwise it can steal user signals.
770  __sanitizer_sigset_t set, old;
771  internal_sigfillset(&set);
772  internal_sigprocmask(SIG_SETMASK, &set, &old);
773  pthread_t th;
774  pthread_create(&th, 0, func, arg);
775  internal_sigprocmask(SIG_SETMASK, &old, 0);
776  return th;
777}
778
779void internal_join_thread(void *th) { pthread_join((pthread_t)th, 0); }
780
781#if !SANITIZER_GO
782static Mutex syslog_lock;
783#  endif
784
785void WriteOneLineToSyslog(const char *s) {
786#if !SANITIZER_GO
787  syslog_lock.CheckLocked();
788  if (GetMacosAlignedVersion() >= MacosVersion(10, 12)) {
789    os_log_error(OS_LOG_DEFAULT, "%{public}s", s);
790  } else {
791    asl_log(nullptr, nullptr, ASL_LEVEL_ERR, "%s", s);
792  }
793#endif
794}
795
796// buffer to store crash report application information
797static char crashreporter_info_buff[__sanitizer::kErrorMessageBufferSize] = {};
798static Mutex crashreporter_info_mutex;
799
800extern "C" {
801// Integrate with crash reporter libraries.
802#if HAVE_CRASHREPORTERCLIENT_H
803CRASH_REPORTER_CLIENT_HIDDEN
804struct crashreporter_annotations_t gCRAnnotations
805    __attribute__((section("__DATA," CRASHREPORTER_ANNOTATIONS_SECTION))) = {
806        CRASHREPORTER_ANNOTATIONS_VERSION,
807        0,
808        0,
809        0,
810        0,
811        0,
812        0,
813#if CRASHREPORTER_ANNOTATIONS_VERSION > 4
814        0,
815#endif
816};
817
818#else
819// fall back to old crashreporter api
820static const char *__crashreporter_info__ __attribute__((__used__)) =
821    &crashreporter_info_buff[0];
822asm(".desc ___crashreporter_info__, 0x10");
823#endif
824
825}  // extern "C"
826
827static void CRAppendCrashLogMessage(const char *msg) {
828  Lock l(&crashreporter_info_mutex);
829  internal_strlcat(crashreporter_info_buff, msg,
830                   sizeof(crashreporter_info_buff));
831#if HAVE_CRASHREPORTERCLIENT_H
832  (void)CRSetCrashLogMessage(crashreporter_info_buff);
833#endif
834}
835
836void LogMessageOnPrintf(const char *str) {
837  // Log all printf output to CrashLog.
838  if (common_flags()->abort_on_error)
839    CRAppendCrashLogMessage(str);
840}
841
842void LogFullErrorReport(const char *buffer) {
843#if !SANITIZER_GO
844  // Log with os_trace. This will make it into the crash log.
845#if SANITIZER_OS_TRACE
846  if (GetMacosAlignedVersion() >= MacosVersion(10, 10)) {
847    // os_trace requires the message (format parameter) to be a string literal.
848    if (internal_strncmp(SanitizerToolName, "AddressSanitizer",
849                         sizeof("AddressSanitizer") - 1) == 0)
850      os_trace("Address Sanitizer reported a failure.");
851    else if (internal_strncmp(SanitizerToolName, "UndefinedBehaviorSanitizer",
852                              sizeof("UndefinedBehaviorSanitizer") - 1) == 0)
853      os_trace("Undefined Behavior Sanitizer reported a failure.");
854    else if (internal_strncmp(SanitizerToolName, "ThreadSanitizer",
855                              sizeof("ThreadSanitizer") - 1) == 0)
856      os_trace("Thread Sanitizer reported a failure.");
857    else
858      os_trace("Sanitizer tool reported a failure.");
859
860    if (common_flags()->log_to_syslog)
861      os_trace("Consult syslog for more information.");
862  }
863#endif
864
865  // Log to syslog.
866  // The logging on OS X may call pthread_create so we need the threading
867  // environment to be fully initialized. Also, this should never be called when
868  // holding the thread registry lock since that may result in a deadlock. If
869  // the reporting thread holds the thread registry mutex, and asl_log waits
870  // for GCD to dispatch a new thread, the process will deadlock, because the
871  // pthread_create wrapper needs to acquire the lock as well.
872  Lock l(&syslog_lock);
873  if (common_flags()->log_to_syslog)
874    WriteToSyslog(buffer);
875
876  // The report is added to CrashLog as part of logging all of Printf output.
877#endif
878}
879
880SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
881#if defined(__x86_64__) || defined(__i386__)
882  ucontext_t *ucontext = static_cast<ucontext_t*>(context);
883  return ucontext->uc_mcontext->__es.__err & 2 /*T_PF_WRITE*/ ? Write : Read;
884#elif defined(__arm64__)
885  ucontext_t *ucontext = static_cast<ucontext_t*>(context);
886  return ucontext->uc_mcontext->__es.__esr & 0x40 /*ISS_DA_WNR*/ ? Write : Read;
887#else
888  return Unknown;
889#endif
890}
891
892bool SignalContext::IsTrueFaultingAddress() const {
893  auto si = static_cast<const siginfo_t *>(siginfo);
894  // "Real" SIGSEGV codes (e.g., SEGV_MAPERR, SEGV_MAPERR) are non-zero.
895  return si->si_signo == SIGSEGV && si->si_code != 0;
896}
897
898#if defined(__aarch64__) && defined(arm_thread_state64_get_sp)
899  #define AARCH64_GET_REG(r) \
900    (uptr)ptrauth_strip(     \
901        (void *)arm_thread_state64_get_##r(ucontext->uc_mcontext->__ss), 0)
902#else
903  #define AARCH64_GET_REG(r) (uptr)ucontext->uc_mcontext->__ss.__##r
904#endif
905
906static void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
907  ucontext_t *ucontext = (ucontext_t*)context;
908# if defined(__aarch64__)
909  *pc = AARCH64_GET_REG(pc);
910  *bp = AARCH64_GET_REG(fp);
911  *sp = AARCH64_GET_REG(sp);
912# elif defined(__x86_64__)
913  *pc = ucontext->uc_mcontext->__ss.__rip;
914  *bp = ucontext->uc_mcontext->__ss.__rbp;
915  *sp = ucontext->uc_mcontext->__ss.__rsp;
916# elif defined(__arm__)
917  *pc = ucontext->uc_mcontext->__ss.__pc;
918  *bp = ucontext->uc_mcontext->__ss.__r[7];
919  *sp = ucontext->uc_mcontext->__ss.__sp;
920# elif defined(__i386__)
921  *pc = ucontext->uc_mcontext->__ss.__eip;
922  *bp = ucontext->uc_mcontext->__ss.__ebp;
923  *sp = ucontext->uc_mcontext->__ss.__esp;
924# else
925# error "Unknown architecture"
926# endif
927}
928
929void SignalContext::InitPcSpBp() {
930  addr = (uptr)ptrauth_strip((void *)addr, 0);
931  GetPcSpBp(context, &pc, &sp, &bp);
932}
933
934// ASan/TSan use mmap in a way that creates ���deallocation gaps��� which triggers
935// EXC_GUARD exceptions on macOS 10.15+ (XNU 19.0+).
936static void DisableMmapExcGuardExceptions() {
937  using task_exc_guard_behavior_t = uint32_t;
938  using task_set_exc_guard_behavior_t =
939      kern_return_t(task_t task, task_exc_guard_behavior_t behavior);
940  auto *set_behavior = (task_set_exc_guard_behavior_t *)dlsym(
941      RTLD_DEFAULT, "task_set_exc_guard_behavior");
942  if (set_behavior == nullptr) return;
943  const task_exc_guard_behavior_t task_exc_guard_none = 0;
944  set_behavior(mach_task_self(), task_exc_guard_none);
945}
946
947static void VerifyInterceptorsWorking();
948static void StripEnv();
949
950void InitializePlatformEarly() {
951  // Only use xnu_fast_mmap when on x86_64 and the kernel supports it.
952  use_xnu_fast_mmap =
953#if defined(__x86_64__)
954      GetDarwinKernelVersion() >= DarwinKernelVersion(17, 5);
955#else
956      false;
957#endif
958  if (GetDarwinKernelVersion() >= DarwinKernelVersion(19, 0))
959    DisableMmapExcGuardExceptions();
960
961#  if !SANITIZER_GO
962  MonotonicNanoTime();  // Call to initialize mach_timebase_info
963  VerifyInterceptorsWorking();
964  StripEnv();
965#  endif
966}
967
968#if !SANITIZER_GO
969static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES";
970LowLevelAllocator allocator_for_env;
971
972static bool ShouldCheckInterceptors() {
973  // Restrict "interceptors working?" check to ASan and TSan.
974  const char *sanitizer_names[] = {"AddressSanitizer", "ThreadSanitizer"};
975  size_t count = sizeof(sanitizer_names) / sizeof(sanitizer_names[0]);
976  for (size_t i = 0; i < count; i++) {
977    if (internal_strcmp(sanitizer_names[i], SanitizerToolName) == 0)
978      return true;
979  }
980  return false;
981}
982
983static void VerifyInterceptorsWorking() {
984  if (!common_flags()->verify_interceptors || !ShouldCheckInterceptors())
985    return;
986
987  // Verify that interceptors really work.  We'll use dlsym to locate
988  // "puts", if interceptors are working, it should really point to
989  // "wrap_puts" within our own dylib.
990  Dl_info info_puts, info_runtime;
991  RAW_CHECK(dladdr(dlsym(RTLD_DEFAULT, "puts"), &info_puts));
992  RAW_CHECK(dladdr((void *)__sanitizer_report_error_summary, &info_runtime));
993  if (internal_strcmp(info_puts.dli_fname, info_runtime.dli_fname) != 0) {
994    Report(
995        "ERROR: Interceptors are not working. This may be because %s is "
996        "loaded too late (e.g. via dlopen). Please launch the executable "
997        "with:\n%s=%s\n",
998        SanitizerToolName, kDyldInsertLibraries, info_runtime.dli_fname);
999    RAW_CHECK("interceptors not installed" && 0);
1000  }
1001}
1002
1003// Change the value of the env var |name|, leaking the original value.
1004// If |name_value| is NULL, the variable is deleted from the environment,
1005// otherwise the corresponding "NAME=value" string is replaced with
1006// |name_value|.
1007static void LeakyResetEnv(const char *name, const char *name_value) {
1008  char **env = GetEnviron();
1009  uptr name_len = internal_strlen(name);
1010  while (*env != 0) {
1011    uptr len = internal_strlen(*env);
1012    if (len > name_len) {
1013      const char *p = *env;
1014      if (!internal_memcmp(p, name, name_len) && p[name_len] == '=') {
1015        // Match.
1016        if (name_value) {
1017          // Replace the old value with the new one.
1018          *env = const_cast<char*>(name_value);
1019        } else {
1020          // Shift the subsequent pointers back.
1021          char **del = env;
1022          do {
1023            del[0] = del[1];
1024          } while (*del++);
1025        }
1026      }
1027    }
1028    env++;
1029  }
1030}
1031
1032static void StripEnv() {
1033  if (!common_flags()->strip_env)
1034    return;
1035
1036  char *dyld_insert_libraries =
1037      const_cast<char *>(GetEnv(kDyldInsertLibraries));
1038  if (!dyld_insert_libraries)
1039    return;
1040
1041  Dl_info info;
1042  RAW_CHECK(dladdr((void *)__sanitizer_report_error_summary, &info));
1043  const char *dylib_name = StripModuleName(info.dli_fname);
1044  bool lib_is_in_env = internal_strstr(dyld_insert_libraries, dylib_name);
1045  if (!lib_is_in_env)
1046    return;
1047
1048  // DYLD_INSERT_LIBRARIES is set and contains the runtime library. Let's remove
1049  // the dylib from the environment variable, because interceptors are installed
1050  // and we don't want our children to inherit the variable.
1051
1052  uptr old_env_len = internal_strlen(dyld_insert_libraries);
1053  uptr dylib_name_len = internal_strlen(dylib_name);
1054  uptr env_name_len = internal_strlen(kDyldInsertLibraries);
1055  // Allocate memory to hold the previous env var name, its value, the '='
1056  // sign and the '\0' char.
1057  char *new_env = (char*)allocator_for_env.Allocate(
1058      old_env_len + 2 + env_name_len);
1059  RAW_CHECK(new_env);
1060  internal_memset(new_env, '\0', old_env_len + 2 + env_name_len);
1061  internal_strncpy(new_env, kDyldInsertLibraries, env_name_len);
1062  new_env[env_name_len] = '=';
1063  char *new_env_pos = new_env + env_name_len + 1;
1064
1065  // Iterate over colon-separated pieces of |dyld_insert_libraries|.
1066  char *piece_start = dyld_insert_libraries;
1067  char *piece_end = NULL;
1068  char *old_env_end = dyld_insert_libraries + old_env_len;
1069  do {
1070    if (piece_start[0] == ':') piece_start++;
1071    piece_end = internal_strchr(piece_start, ':');
1072    if (!piece_end) piece_end = dyld_insert_libraries + old_env_len;
1073    if ((uptr)(piece_start - dyld_insert_libraries) > old_env_len) break;
1074    uptr piece_len = piece_end - piece_start;
1075
1076    char *filename_start =
1077        (char *)internal_memrchr(piece_start, '/', piece_len);
1078    uptr filename_len = piece_len;
1079    if (filename_start) {
1080      filename_start += 1;
1081      filename_len = piece_len - (filename_start - piece_start);
1082    } else {
1083      filename_start = piece_start;
1084    }
1085
1086    // If the current piece isn't the runtime library name,
1087    // append it to new_env.
1088    if ((dylib_name_len != filename_len) ||
1089        (internal_memcmp(filename_start, dylib_name, dylib_name_len) != 0)) {
1090      if (new_env_pos != new_env + env_name_len + 1) {
1091        new_env_pos[0] = ':';
1092        new_env_pos++;
1093      }
1094      internal_strncpy(new_env_pos, piece_start, piece_len);
1095      new_env_pos += piece_len;
1096    }
1097    // Move on to the next piece.
1098    piece_start = piece_end;
1099  } while (piece_start < old_env_end);
1100
1101  // Can't use setenv() here, because it requires the allocator to be
1102  // initialized.
1103  // FIXME: instead of filtering DYLD_INSERT_LIBRARIES here, do it in
1104  // a separate function called after InitializeAllocator().
1105  if (new_env_pos == new_env + env_name_len + 1) new_env = NULL;
1106  LeakyResetEnv(kDyldInsertLibraries, new_env);
1107}
1108#endif  // SANITIZER_GO
1109
1110char **GetArgv() {
1111  return *_NSGetArgv();
1112}
1113
1114#if SANITIZER_IOS && !SANITIZER_IOSSIM
1115// The task_vm_info struct is normally provided by the macOS SDK, but we need
1116// fields only available in 10.12+. Declare the struct manually to be able to
1117// build against older SDKs.
1118struct __sanitizer_task_vm_info {
1119  mach_vm_size_t virtual_size;
1120  integer_t region_count;
1121  integer_t page_size;
1122  mach_vm_size_t resident_size;
1123  mach_vm_size_t resident_size_peak;
1124  mach_vm_size_t device;
1125  mach_vm_size_t device_peak;
1126  mach_vm_size_t internal;
1127  mach_vm_size_t internal_peak;
1128  mach_vm_size_t external;
1129  mach_vm_size_t external_peak;
1130  mach_vm_size_t reusable;
1131  mach_vm_size_t reusable_peak;
1132  mach_vm_size_t purgeable_volatile_pmap;
1133  mach_vm_size_t purgeable_volatile_resident;
1134  mach_vm_size_t purgeable_volatile_virtual;
1135  mach_vm_size_t compressed;
1136  mach_vm_size_t compressed_peak;
1137  mach_vm_size_t compressed_lifetime;
1138  mach_vm_size_t phys_footprint;
1139  mach_vm_address_t min_address;
1140  mach_vm_address_t max_address;
1141};
1142#define __SANITIZER_TASK_VM_INFO_COUNT ((mach_msg_type_number_t) \
1143    (sizeof(__sanitizer_task_vm_info) / sizeof(natural_t)))
1144
1145static uptr GetTaskInfoMaxAddress() {
1146  __sanitizer_task_vm_info vm_info = {} /* zero initialize */;
1147  mach_msg_type_number_t count = __SANITIZER_TASK_VM_INFO_COUNT;
1148  int err = task_info(mach_task_self(), TASK_VM_INFO, (int *)&vm_info, &count);
1149  return err ? 0 : vm_info.max_address;
1150}
1151
1152uptr GetMaxUserVirtualAddress() {
1153  static uptr max_vm = GetTaskInfoMaxAddress();
1154  if (max_vm != 0) {
1155    const uptr ret_value = max_vm - 1;
1156    CHECK_LE(ret_value, SANITIZER_MMAP_RANGE_SIZE);
1157    return ret_value;
1158  }
1159
1160  // xnu cannot provide vm address limit
1161# if SANITIZER_WORDSIZE == 32
1162  constexpr uptr fallback_max_vm = 0xffe00000 - 1;
1163# else
1164  constexpr uptr fallback_max_vm = 0x200000000 - 1;
1165# endif
1166  static_assert(fallback_max_vm <= SANITIZER_MMAP_RANGE_SIZE,
1167                "Max virtual address must be less than mmap range size.");
1168  return fallback_max_vm;
1169}
1170
1171#else // !SANITIZER_IOS
1172
1173uptr GetMaxUserVirtualAddress() {
1174# if SANITIZER_WORDSIZE == 64
1175  constexpr uptr max_vm = (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
1176# else // SANITIZER_WORDSIZE == 32
1177  static_assert(SANITIZER_WORDSIZE == 32, "Wrong wordsize");
1178  constexpr uptr max_vm = (1ULL << 32) - 1;  // 0xffffffff;
1179# endif
1180  static_assert(max_vm <= SANITIZER_MMAP_RANGE_SIZE,
1181                "Max virtual address must be less than mmap range size.");
1182  return max_vm;
1183}
1184#endif
1185
1186uptr GetMaxVirtualAddress() {
1187  return GetMaxUserVirtualAddress();
1188}
1189
1190uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
1191                      uptr min_shadow_base_alignment, uptr &high_mem_end) {
1192  const uptr granularity = GetMmapGranularity();
1193  const uptr alignment =
1194      Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
1195  const uptr left_padding =
1196      Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);
1197
1198  uptr space_size = shadow_size_bytes + left_padding;
1199
1200  uptr largest_gap_found = 0;
1201  uptr max_occupied_addr = 0;
1202  VReport(2, "FindDynamicShadowStart, space_size = %p\n", (void *)space_size);
1203  uptr shadow_start =
1204      FindAvailableMemoryRange(space_size, alignment, granularity,
1205                               &largest_gap_found, &max_occupied_addr);
1206  // If the shadow doesn't fit, restrict the address space to make it fit.
1207  if (shadow_start == 0) {
1208    VReport(
1209        2,
1210        "Shadow doesn't fit, largest_gap_found = %p, max_occupied_addr = %p\n",
1211        (void *)largest_gap_found, (void *)max_occupied_addr);
1212    uptr new_max_vm = RoundDownTo(largest_gap_found << shadow_scale, alignment);
1213    if (new_max_vm < max_occupied_addr) {
1214      Report("Unable to find a memory range for dynamic shadow.\n");
1215      Report(
1216          "space_size = %p, largest_gap_found = %p, max_occupied_addr = %p, "
1217          "new_max_vm = %p\n",
1218          (void *)space_size, (void *)largest_gap_found,
1219          (void *)max_occupied_addr, (void *)new_max_vm);
1220      CHECK(0 && "cannot place shadow");
1221    }
1222    RestrictMemoryToMaxAddress(new_max_vm);
1223    high_mem_end = new_max_vm - 1;
1224    space_size = (high_mem_end >> shadow_scale) + left_padding;
1225    VReport(2, "FindDynamicShadowStart, space_size = %p\n", (void *)space_size);
1226    shadow_start = FindAvailableMemoryRange(space_size, alignment, granularity,
1227                                            nullptr, nullptr);
1228    if (shadow_start == 0) {
1229      Report("Unable to find a memory range after restricting VM.\n");
1230      CHECK(0 && "cannot place shadow after restricting vm");
1231    }
1232  }
1233  CHECK_NE((uptr)0, shadow_start);
1234  CHECK(IsAligned(shadow_start, alignment));
1235  return shadow_start;
1236}
1237
1238uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
1239                                uptr num_aliases, uptr ring_buffer_size) {
1240  CHECK(false && "HWASan aliasing is unimplemented on Mac");
1241  return 0;
1242}
1243
1244uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
1245                              uptr *largest_gap_found,
1246                              uptr *max_occupied_addr) {
1247  typedef vm_region_submap_short_info_data_64_t RegionInfo;
1248  enum { kRegionInfoSize = VM_REGION_SUBMAP_SHORT_INFO_COUNT_64 };
1249  // Start searching for available memory region past PAGEZERO, which is
1250  // 4KB on 32-bit and 4GB on 64-bit.
1251  mach_vm_address_t start_address =
1252    (SANITIZER_WORDSIZE == 32) ? 0x000000001000 : 0x000100000000;
1253
1254  const mach_vm_address_t max_vm_address = GetMaxVirtualAddress() + 1;
1255  mach_vm_address_t address = start_address;
1256  mach_vm_address_t free_begin = start_address;
1257  kern_return_t kr = KERN_SUCCESS;
1258  if (largest_gap_found) *largest_gap_found = 0;
1259  if (max_occupied_addr) *max_occupied_addr = 0;
1260  while (kr == KERN_SUCCESS) {
1261    mach_vm_size_t vmsize = 0;
1262    natural_t depth = 0;
1263    RegionInfo vminfo;
1264    mach_msg_type_number_t count = kRegionInfoSize;
1265    kr = mach_vm_region_recurse(mach_task_self(), &address, &vmsize, &depth,
1266                                (vm_region_info_t)&vminfo, &count);
1267    if (kr == KERN_INVALID_ADDRESS) {
1268      // No more regions beyond "address", consider the gap at the end of VM.
1269      address = max_vm_address;
1270      vmsize = 0;
1271    } else {
1272      if (max_occupied_addr) *max_occupied_addr = address + vmsize;
1273    }
1274    if (free_begin != address) {
1275      // We found a free region [free_begin..address-1].
1276      uptr gap_start = RoundUpTo((uptr)free_begin + left_padding, alignment);
1277      uptr gap_end = RoundDownTo((uptr)Min(address, max_vm_address), alignment);
1278      uptr gap_size = gap_end > gap_start ? gap_end - gap_start : 0;
1279      if (size < gap_size) {
1280        return gap_start;
1281      }
1282
1283      if (largest_gap_found && *largest_gap_found < gap_size) {
1284        *largest_gap_found = gap_size;
1285      }
1286    }
1287    // Move to the next region.
1288    address += vmsize;
1289    free_begin = address;
1290  }
1291
1292  // We looked at all free regions and could not find one large enough.
1293  return 0;
1294}
1295
1296// FIXME implement on this platform.
1297void GetMemoryProfile(fill_profile_f cb, uptr *stats) {}
1298
1299void SignalContext::DumpAllRegisters(void *context) {
1300  Report("Register values:\n");
1301
1302  ucontext_t *ucontext = (ucontext_t*)context;
1303# define DUMPREG64(r) \
1304    Printf("%s = 0x%016llx  ", #r, ucontext->uc_mcontext->__ss.__ ## r);
1305# define DUMPREGA64(r) \
1306    Printf("   %s = 0x%016lx  ", #r, AARCH64_GET_REG(r));
1307# define DUMPREG32(r) \
1308    Printf("%s = 0x%08x  ", #r, ucontext->uc_mcontext->__ss.__ ## r);
1309# define DUMPREG_(r)   Printf(" "); DUMPREG(r);
1310# define DUMPREG__(r)  Printf("  "); DUMPREG(r);
1311# define DUMPREG___(r) Printf("   "); DUMPREG(r);
1312
1313# if defined(__x86_64__)
1314#  define DUMPREG(r) DUMPREG64(r)
1315  DUMPREG(rax); DUMPREG(rbx); DUMPREG(rcx); DUMPREG(rdx); Printf("\n");
1316  DUMPREG(rdi); DUMPREG(rsi); DUMPREG(rbp); DUMPREG(rsp); Printf("\n");
1317  DUMPREG_(r8); DUMPREG_(r9); DUMPREG(r10); DUMPREG(r11); Printf("\n");
1318  DUMPREG(r12); DUMPREG(r13); DUMPREG(r14); DUMPREG(r15); Printf("\n");
1319# elif defined(__i386__)
1320#  define DUMPREG(r) DUMPREG32(r)
1321  DUMPREG(eax); DUMPREG(ebx); DUMPREG(ecx); DUMPREG(edx); Printf("\n");
1322  DUMPREG(edi); DUMPREG(esi); DUMPREG(ebp); DUMPREG(esp); Printf("\n");
1323# elif defined(__aarch64__)
1324#  define DUMPREG(r) DUMPREG64(r)
1325  DUMPREG_(x[0]); DUMPREG_(x[1]); DUMPREG_(x[2]); DUMPREG_(x[3]); Printf("\n");
1326  DUMPREG_(x[4]); DUMPREG_(x[5]); DUMPREG_(x[6]); DUMPREG_(x[7]); Printf("\n");
1327  DUMPREG_(x[8]); DUMPREG_(x[9]); DUMPREG(x[10]); DUMPREG(x[11]); Printf("\n");
1328  DUMPREG(x[12]); DUMPREG(x[13]); DUMPREG(x[14]); DUMPREG(x[15]); Printf("\n");
1329  DUMPREG(x[16]); DUMPREG(x[17]); DUMPREG(x[18]); DUMPREG(x[19]); Printf("\n");
1330  DUMPREG(x[20]); DUMPREG(x[21]); DUMPREG(x[22]); DUMPREG(x[23]); Printf("\n");
1331  DUMPREG(x[24]); DUMPREG(x[25]); DUMPREG(x[26]); DUMPREG(x[27]); Printf("\n");
1332  DUMPREG(x[28]); DUMPREGA64(fp); DUMPREGA64(lr); DUMPREGA64(sp); Printf("\n");
1333# elif defined(__arm__)
1334#  define DUMPREG(r) DUMPREG32(r)
1335  DUMPREG_(r[0]); DUMPREG_(r[1]); DUMPREG_(r[2]); DUMPREG_(r[3]); Printf("\n");
1336  DUMPREG_(r[4]); DUMPREG_(r[5]); DUMPREG_(r[6]); DUMPREG_(r[7]); Printf("\n");
1337  DUMPREG_(r[8]); DUMPREG_(r[9]); DUMPREG(r[10]); DUMPREG(r[11]); Printf("\n");
1338  DUMPREG(r[12]); DUMPREG___(sp); DUMPREG___(lr); DUMPREG___(pc); Printf("\n");
1339# else
1340# error "Unknown architecture"
1341# endif
1342
1343# undef DUMPREG64
1344# undef DUMPREG32
1345# undef DUMPREG_
1346# undef DUMPREG__
1347# undef DUMPREG___
1348# undef DUMPREG
1349}
1350
1351static inline bool CompareBaseAddress(const LoadedModule &a,
1352                                      const LoadedModule &b) {
1353  return a.base_address() < b.base_address();
1354}
1355
1356void FormatUUID(char *out, uptr size, const u8 *uuid) {
1357  internal_snprintf(out, size,
1358                    "<%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-"
1359                    "%02X%02X%02X%02X%02X%02X>",
1360                    uuid[0], uuid[1], uuid[2], uuid[3], uuid[4], uuid[5],
1361                    uuid[6], uuid[7], uuid[8], uuid[9], uuid[10], uuid[11],
1362                    uuid[12], uuid[13], uuid[14], uuid[15]);
1363}
1364
1365void DumpProcessMap() {
1366  Printf("Process module map:\n");
1367  MemoryMappingLayout memory_mapping(false);
1368  InternalMmapVector<LoadedModule> modules;
1369  modules.reserve(128);
1370  memory_mapping.DumpListOfModules(&modules);
1371  Sort(modules.data(), modules.size(), CompareBaseAddress);
1372  for (uptr i = 0; i < modules.size(); ++i) {
1373    char uuid_str[128];
1374    FormatUUID(uuid_str, sizeof(uuid_str), modules[i].uuid());
1375    Printf("0x%zx-0x%zx %s (%s) %s\n", modules[i].base_address(),
1376           modules[i].max_address(), modules[i].full_name(),
1377           ModuleArchToString(modules[i].arch()), uuid_str);
1378  }
1379  Printf("End of module map.\n");
1380}
1381
1382void CheckNoDeepBind(const char *filename, int flag) {
1383  // Do nothing.
1384}
1385
1386bool GetRandom(void *buffer, uptr length, bool blocking) {
1387  if (!buffer || !length || length > 256)
1388    return false;
1389  // arc4random never fails.
1390  REAL(arc4random_buf)(buffer, length);
1391  return true;
1392}
1393
1394u32 GetNumberOfCPUs() {
1395  return (u32)sysconf(_SC_NPROCESSORS_ONLN);
1396}
1397
1398void InitializePlatformCommonFlags(CommonFlags *cf) {}
1399
1400// Pthread introspection hook
1401//
1402// * GCD worker threads are created without a call to pthread_create(), but we
1403//   still need to register these threads (with ThreadCreate/Start()).
1404// * We use the "pthread introspection hook" below to observe the creation of
1405//   such threads.
1406// * GCD worker threads don't have parent threads and the CREATE event is
1407//   delivered in the context of the thread itself.  CREATE events for regular
1408//   threads, are delivered on the parent.  We use this to tell apart which
1409//   threads are GCD workers with `thread == pthread_self()`.
1410//
1411static pthread_introspection_hook_t prev_pthread_introspection_hook;
1412static ThreadEventCallbacks thread_event_callbacks;
1413
1414static void sanitizer_pthread_introspection_hook(unsigned int event,
1415                                                 pthread_t thread, void *addr,
1416                                                 size_t size) {
1417  // create -> start -> terminate -> destroy
1418  // * create/destroy are usually (not guaranteed) delivered on the parent and
1419  //   track resource allocation/reclamation
1420  // * start/terminate are guaranteed to be delivered in the context of the
1421  //   thread and give hooks into "just after (before) thread starts (stops)
1422  //   executing"
1423  DCHECK(event >= PTHREAD_INTROSPECTION_THREAD_CREATE &&
1424         event <= PTHREAD_INTROSPECTION_THREAD_DESTROY);
1425
1426  if (event == PTHREAD_INTROSPECTION_THREAD_CREATE) {
1427    bool gcd_worker = (thread == pthread_self());
1428    if (thread_event_callbacks.create)
1429      thread_event_callbacks.create((uptr)thread, gcd_worker);
1430  } else if (event == PTHREAD_INTROSPECTION_THREAD_START) {
1431    CHECK_EQ(thread, pthread_self());
1432    if (thread_event_callbacks.start)
1433      thread_event_callbacks.start((uptr)thread);
1434  }
1435
1436  if (prev_pthread_introspection_hook)
1437    prev_pthread_introspection_hook(event, thread, addr, size);
1438
1439  if (event == PTHREAD_INTROSPECTION_THREAD_TERMINATE) {
1440    CHECK_EQ(thread, pthread_self());
1441    if (thread_event_callbacks.terminate)
1442      thread_event_callbacks.terminate((uptr)thread);
1443  } else if (event == PTHREAD_INTROSPECTION_THREAD_DESTROY) {
1444    if (thread_event_callbacks.destroy)
1445      thread_event_callbacks.destroy((uptr)thread);
1446  }
1447}
1448
1449void InstallPthreadIntrospectionHook(const ThreadEventCallbacks &callbacks) {
1450  thread_event_callbacks = callbacks;
1451  prev_pthread_introspection_hook =
1452      pthread_introspection_hook_install(&sanitizer_pthread_introspection_hook);
1453}
1454
1455}  // namespace __sanitizer
1456
1457#endif  // SANITIZER_APPLE
1458