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_MAC
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_internal_defs.h"
29 #include "sanitizer_libc.h"
30 #include "sanitizer_platform_limits_posix.h"
31 #include "sanitizer_procmaps.h"
32 #include "sanitizer_ptrauth.h"
33 
34 #if !SANITIZER_IOS
35 #include <crt_externs.h>  // for _NSGetEnviron
36 #else
37 extern char **environ;
38 #endif
39 
40 #if defined(__has_include) && __has_include(<os/trace.h>)
41 #define SANITIZER_OS_TRACE 1
42 #include <os/trace.h>
43 #else
44 #define SANITIZER_OS_TRACE 0
45 #endif
46 
47 // import new crash reporting api
48 #if defined(__has_include) && __has_include(<CrashReporterClient.h>)
49 #define HAVE_CRASHREPORTERCLIENT_H 1
50 #include <CrashReporterClient.h>
51 #else
52 #define HAVE_CRASHREPORTERCLIENT_H 0
53 #endif
54 
55 #if !SANITIZER_IOS
56 #include <crt_externs.h>  // for _NSGetArgv and _NSGetEnviron
57 #else
58 extern "C" {
59   extern char ***_NSGetArgv(void);
60 }
61 #endif
62 
63 #include <asl.h>
64 #include <dlfcn.h>  // for dladdr()
65 #include <errno.h>
66 #include <fcntl.h>
67 #include <libkern/OSAtomic.h>
68 #include <mach-o/dyld.h>
69 #include <mach/mach.h>
70 #include <mach/mach_time.h>
71 #include <mach/vm_statistics.h>
72 #include <malloc/malloc.h>
73 #include <os/log.h>
74 #include <pthread.h>
75 #include <sched.h>
76 #include <signal.h>
77 #include <spawn.h>
78 #include <stdlib.h>
79 #include <sys/ioctl.h>
80 #include <sys/mman.h>
81 #include <sys/resource.h>
82 #include <sys/stat.h>
83 #include <sys/sysctl.h>
84 #include <sys/types.h>
85 #include <sys/wait.h>
86 #include <unistd.h>
87 #include <util.h>
88 
89 // From <crt_externs.h>, but we don't have that file on iOS.
90 extern "C" {
91   extern char ***_NSGetArgv(void);
92   extern char ***_NSGetEnviron(void);
93 }
94 
95 // From <mach/mach_vm.h>, but we don't have that file on iOS.
96 extern "C" {
97   extern kern_return_t mach_vm_region_recurse(
98     vm_map_t target_task,
99     mach_vm_address_t *address,
100     mach_vm_size_t *size,
101     natural_t *nesting_depth,
102     vm_region_recurse_info_t info,
103     mach_msg_type_number_t *infoCnt);
104 }
105 
106 namespace __sanitizer {
107 
108 #include "sanitizer_syscall_generic.inc"
109 
110 // Direct syscalls, don't call libmalloc hooks (but not available on 10.6).
111 extern "C" void *__mmap(void *addr, size_t len, int prot, int flags, int fildes,
112                         off_t off) SANITIZER_WEAK_ATTRIBUTE;
113 extern "C" int __munmap(void *, size_t) SANITIZER_WEAK_ATTRIBUTE;
114 
115 // ---------------------- sanitizer_libc.h
116 
117 // From <mach/vm_statistics.h>, but not on older OSs.
118 #ifndef VM_MEMORY_SANITIZER
119 #define VM_MEMORY_SANITIZER 99
120 #endif
121 
122 // XNU on Darwin provides a mmap flag that optimizes allocation/deallocation of
123 // giant memory regions (i.e. shadow memory regions).
124 #define kXnuFastMmapFd 0x4
125 static size_t kXnuFastMmapThreshold = 2 << 30; // 2 GB
126 static bool use_xnu_fast_mmap = false;
127 
128 uptr internal_mmap(void *addr, size_t length, int prot, int flags,
129                    int fd, u64 offset) {
130   if (fd == -1) {
131     fd = VM_MAKE_TAG(VM_MEMORY_SANITIZER);
132     if (length >= kXnuFastMmapThreshold) {
133       if (use_xnu_fast_mmap) fd |= kXnuFastMmapFd;
134     }
135   }
136   if (&__mmap) return (uptr)__mmap(addr, length, prot, flags, fd, offset);
137   return (uptr)mmap(addr, length, prot, flags, fd, offset);
138 }
139 
140 uptr internal_munmap(void *addr, uptr length) {
141   if (&__munmap) return __munmap(addr, length);
142   return munmap(addr, length);
143 }
144 
145 uptr internal_mremap(void *old_address, uptr old_size, uptr new_size, int flags,
146                      void *new_address) {
147   CHECK(false && "internal_mremap is unimplemented on Mac");
148   return 0;
149 }
150 
151 int internal_mprotect(void *addr, uptr length, int prot) {
152   return mprotect(addr, length, prot);
153 }
154 
155 int internal_madvise(uptr addr, uptr length, int advice) {
156   return madvise((void *)addr, length, advice);
157 }
158 
159 uptr internal_close(fd_t fd) {
160   return close(fd);
161 }
162 
163 uptr internal_open(const char *filename, int flags) {
164   return open(filename, flags);
165 }
166 
167 uptr internal_open(const char *filename, int flags, u32 mode) {
168   return open(filename, flags, mode);
169 }
170 
171 uptr internal_read(fd_t fd, void *buf, uptr count) {
172   return read(fd, buf, count);
173 }
174 
175 uptr internal_write(fd_t fd, const void *buf, uptr count) {
176   return write(fd, buf, count);
177 }
178 
179 uptr internal_stat(const char *path, void *buf) {
180   return stat(path, (struct stat *)buf);
181 }
182 
183 uptr internal_lstat(const char *path, void *buf) {
184   return lstat(path, (struct stat *)buf);
185 }
186 
187 uptr internal_fstat(fd_t fd, void *buf) {
188   return fstat(fd, (struct stat *)buf);
189 }
190 
191 uptr internal_filesize(fd_t fd) {
192   struct stat st;
193   if (internal_fstat(fd, &st))
194     return -1;
195   return (uptr)st.st_size;
196 }
197 
198 uptr internal_dup(int oldfd) {
199   return dup(oldfd);
200 }
201 
202 uptr internal_dup2(int oldfd, int newfd) {
203   return dup2(oldfd, newfd);
204 }
205 
206 uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
207   return readlink(path, buf, bufsize);
208 }
209 
210 uptr internal_unlink(const char *path) {
211   return unlink(path);
212 }
213 
214 uptr internal_sched_yield() {
215   return sched_yield();
216 }
217 
218 void internal__exit(int exitcode) {
219   _exit(exitcode);
220 }
221 
222 unsigned int internal_sleep(unsigned int seconds) {
223   return sleep(seconds);
224 }
225 
226 uptr internal_getpid() {
227   return getpid();
228 }
229 
230 int internal_dlinfo(void *handle, int request, void *p) {
231   UNIMPLEMENTED();
232 }
233 
234 int internal_sigaction(int signum, const void *act, void *oldact) {
235   return sigaction(signum,
236                    (const struct sigaction *)act, (struct sigaction *)oldact);
237 }
238 
239 void internal_sigfillset(__sanitizer_sigset_t *set) { sigfillset(set); }
240 
241 uptr 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).
248 extern "C" pid_t __fork(void) SANITIZER_WEAK_ATTRIBUTE;
249 
250 int internal_fork() {
251   if (&__fork)
252     return __fork();
253   return fork();
254 }
255 
256 int 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 
262 int 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 
268 static fd_t internal_spawn_impl(const char *argv[], const char *envp[],
269                                 pid_t *pid) {
270   fd_t master_fd = kInvalidFd;
271   fd_t slave_fd = kInvalidFd;
272 
273   auto fd_closer = at_scope_exit([&] {
274     internal_close(master_fd);
275     internal_close(slave_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   master_fd = posix_openpt(O_RDWR);
282   if (master_fd == kInvalidFd) return kInvalidFd;
283 
284   int res = grantpt(master_fd) || unlockpt(master_fd);
285   if (res != 0) return kInvalidFd;
286 
287   // Use TIOCPTYGNAME instead of ptsname() to avoid threading problems.
288   char slave_pty_name[128];
289   res = ioctl(master_fd, TIOCPTYGNAME, slave_pty_name);
290   if (res == -1) return kInvalidFd;
291 
292   slave_fd = internal_open(slave_pty_name, O_RDWR);
293   if (slave_fd == kInvalidFd) return kInvalidFd;
294 
295   // File descriptor actions
296   posix_spawn_file_actions_t acts;
297   res = posix_spawn_file_actions_init(&acts);
298   if (res != 0) return kInvalidFd;
299 
300   auto acts_cleanup = at_scope_exit([&] {
301     posix_spawn_file_actions_destroy(&acts);
302   });
303 
304   res = posix_spawn_file_actions_adddup2(&acts, slave_fd, STDIN_FILENO) ||
305         posix_spawn_file_actions_adddup2(&acts, slave_fd, STDOUT_FILENO) ||
306         posix_spawn_file_actions_addclose(&acts, slave_fd);
307   if (res != 0) return kInvalidFd;
308 
309   // Spawn attributes
310   posix_spawnattr_t attrs;
311   res = posix_spawnattr_init(&attrs);
312   if (res != 0) return kInvalidFd;
313 
314   auto attrs_cleanup  = at_scope_exit([&] {
315     posix_spawnattr_destroy(&attrs);
316   });
317 
318   // In the spawned process, close all file descriptors that are not explicitly
319   // described by the file actions object. This is Darwin-specific extension.
320   res = posix_spawnattr_setflags(&attrs, POSIX_SPAWN_CLOEXEC_DEFAULT);
321   if (res != 0) return kInvalidFd;
322 
323   // posix_spawn
324   char **argv_casted = const_cast<char **>(argv);
325   char **envp_casted = const_cast<char **>(envp);
326   res = posix_spawn(pid, argv[0], &acts, &attrs, argv_casted, envp_casted);
327   if (res != 0) return kInvalidFd;
328 
329   // Disable echo in the new terminal, disable CR.
330   struct termios termflags;
331   tcgetattr(master_fd, &termflags);
332   termflags.c_oflag &= ~ONLCR;
333   termflags.c_lflag &= ~ECHO;
334   tcsetattr(master_fd, TCSANOW, &termflags);
335 
336   // On success, do not close master_fd on scope exit.
337   fd_t fd = master_fd;
338   master_fd = kInvalidFd;
339 
340   return fd;
341 }
342 
343 fd_t internal_spawn(const char *argv[], const char *envp[], pid_t *pid) {
344   // The client program may close its stdin and/or stdout and/or stderr thus
345   // allowing open/posix_openpt to reuse file descriptors 0, 1 or 2. In this
346   // case the communication is broken if either the parent or the child tries to
347   // close or duplicate these descriptors. We temporarily reserve these
348   // descriptors here to prevent this.
349   fd_t low_fds[3];
350   size_t count = 0;
351 
352   for (; count < 3; count++) {
353     low_fds[count] = posix_openpt(O_RDWR);
354     if (low_fds[count] >= STDERR_FILENO)
355       break;
356   }
357 
358   fd_t fd = internal_spawn_impl(argv, envp, pid);
359 
360   for (; count > 0; count--) {
361     internal_close(low_fds[count]);
362   }
363 
364   return fd;
365 }
366 
367 uptr internal_rename(const char *oldpath, const char *newpath) {
368   return rename(oldpath, newpath);
369 }
370 
371 uptr internal_ftruncate(fd_t fd, uptr size) {
372   return ftruncate(fd, size);
373 }
374 
375 uptr internal_execve(const char *filename, char *const argv[],
376                      char *const envp[]) {
377   return execve(filename, argv, envp);
378 }
379 
380 uptr internal_waitpid(int pid, int *status, int options) {
381   return waitpid(pid, status, options);
382 }
383 
384 // ----------------- sanitizer_common.h
385 bool FileExists(const char *filename) {
386   if (ShouldMockFailureToOpen(filename))
387     return false;
388   struct stat st;
389   if (stat(filename, &st))
390     return false;
391   // Sanity check: filename is a regular file.
392   return S_ISREG(st.st_mode);
393 }
394 
395 tid_t GetTid() {
396   tid_t tid;
397   pthread_threadid_np(nullptr, &tid);
398   return tid;
399 }
400 
401 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
402                                 uptr *stack_bottom) {
403   CHECK(stack_top);
404   CHECK(stack_bottom);
405   uptr stacksize = pthread_get_stacksize_np(pthread_self());
406   // pthread_get_stacksize_np() returns an incorrect stack size for the main
407   // thread on Mavericks. See
408   // https://github.com/google/sanitizers/issues/261
409   if ((GetMacosAlignedVersion() >= MacosVersion(10, 9)) && at_initialization &&
410       stacksize == (1 << 19))  {
411     struct rlimit rl;
412     CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
413     // Most often rl.rlim_cur will be the desired 8M.
414     if (rl.rlim_cur < kMaxThreadStackSize) {
415       stacksize = rl.rlim_cur;
416     } else {
417       stacksize = kMaxThreadStackSize;
418     }
419   }
420   void *stackaddr = pthread_get_stackaddr_np(pthread_self());
421   *stack_top = (uptr)stackaddr;
422   *stack_bottom = *stack_top - stacksize;
423 }
424 
425 char **GetEnviron() {
426 #if !SANITIZER_IOS
427   char ***env_ptr = _NSGetEnviron();
428   if (!env_ptr) {
429     Report("_NSGetEnviron() returned NULL. Please make sure __asan_init() is "
430            "called after libSystem_initializer().\n");
431     CHECK(env_ptr);
432   }
433   char **environ = *env_ptr;
434 #endif
435   CHECK(environ);
436   return environ;
437 }
438 
439 const char *GetEnv(const char *name) {
440   char **env = GetEnviron();
441   uptr name_len = internal_strlen(name);
442   while (*env != 0) {
443     uptr len = internal_strlen(*env);
444     if (len > name_len) {
445       const char *p = *env;
446       if (!internal_memcmp(p, name, name_len) &&
447           p[name_len] == '=') {  // Match.
448         return *env + name_len + 1;  // String starting after =.
449       }
450     }
451     env++;
452   }
453   return 0;
454 }
455 
456 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
457   CHECK_LE(kMaxPathLength, buf_len);
458 
459   // On OS X the executable path is saved to the stack by dyld. Reading it
460   // from there is much faster than calling dladdr, especially for large
461   // binaries with symbols.
462   InternalMmapVector<char> exe_path(kMaxPathLength);
463   uint32_t size = exe_path.size();
464   if (_NSGetExecutablePath(exe_path.data(), &size) == 0 &&
465       realpath(exe_path.data(), buf) != 0) {
466     return internal_strlen(buf);
467   }
468   return 0;
469 }
470 
471 uptr ReadLongProcessName(/*out*/char *buf, uptr buf_len) {
472   return ReadBinaryName(buf, buf_len);
473 }
474 
475 void ReExec() {
476   UNIMPLEMENTED();
477 }
478 
479 void CheckASLR() {
480   // Do nothing
481 }
482 
483 void CheckMPROTECT() {
484   // Do nothing
485 }
486 
487 uptr GetPageSize() {
488   return sysconf(_SC_PAGESIZE);
489 }
490 
491 extern "C" unsigned malloc_num_zones;
492 extern "C" malloc_zone_t **malloc_zones;
493 malloc_zone_t sanitizer_zone;
494 
495 // We need to make sure that sanitizer_zone is registered as malloc_zones[0]. If
496 // libmalloc tries to set up a different zone as malloc_zones[0], it will call
497 // mprotect(malloc_zones, ..., PROT_READ).  This interceptor will catch that and
498 // make sure we are still the first (default) zone.
499 void MprotectMallocZones(void *addr, int prot) {
500   if (addr == malloc_zones && prot == PROT_READ) {
501     if (malloc_num_zones > 1 && malloc_zones[0] != &sanitizer_zone) {
502       for (unsigned i = 1; i < malloc_num_zones; i++) {
503         if (malloc_zones[i] == &sanitizer_zone) {
504           // Swap malloc_zones[0] and malloc_zones[i].
505           malloc_zones[i] = malloc_zones[0];
506           malloc_zones[0] = &sanitizer_zone;
507           break;
508         }
509       }
510     }
511   }
512 }
513 
514 BlockingMutex::BlockingMutex() {
515   internal_memset(this, 0, sizeof(*this));
516 }
517 
518 void BlockingMutex::Lock() {
519   CHECK(sizeof(OSSpinLock) <= sizeof(opaque_storage_));
520   CHECK_EQ(OS_SPINLOCK_INIT, 0);
521   CHECK_EQ(owner_, 0);
522   OSSpinLockLock((OSSpinLock*)&opaque_storage_);
523 }
524 
525 void BlockingMutex::Unlock() {
526   OSSpinLockUnlock((OSSpinLock*)&opaque_storage_);
527 }
528 
529 void BlockingMutex::CheckLocked() {
530   CHECK_NE(*(OSSpinLock*)&opaque_storage_, 0);
531 }
532 
533 u64 NanoTime() {
534   timeval tv;
535   internal_memset(&tv, 0, sizeof(tv));
536   gettimeofday(&tv, 0);
537   return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
538 }
539 
540 // This needs to be called during initialization to avoid being racy.
541 u64 MonotonicNanoTime() {
542   static mach_timebase_info_data_t timebase_info;
543   if (timebase_info.denom == 0) mach_timebase_info(&timebase_info);
544   return (mach_absolute_time() * timebase_info.numer) / timebase_info.denom;
545 }
546 
547 uptr GetTlsSize() {
548   return 0;
549 }
550 
551 void InitTlsSize() {
552 }
553 
554 uptr TlsBaseAddr() {
555   uptr segbase = 0;
556 #if defined(__x86_64__)
557   asm("movq %%gs:0,%0" : "=r"(segbase));
558 #elif defined(__i386__)
559   asm("movl %%gs:0,%0" : "=r"(segbase));
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.
567 uptr TlsSize() {
568 #if defined(__x86_64__) || defined(__i386__)
569   return 1024 * sizeof(uptr);
570 #else
571   return 0;
572 #endif
573 }
574 
575 void 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 
592 void ListOfModules::init() {
593   clearOrInit();
594   MemoryMappingLayout memory_mapping(false);
595   memory_mapping.DumpListOfModules(&modules_);
596 }
597 
598 void ListOfModules::fallbackInit() { clear(); }
599 
600 static 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 
618 HandleSignalMode 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
630 constexpr 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 
636 using VersStr = char[64];
637 
638 static 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 
655 static 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 
686 void 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
698 static 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 
717 static 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 
728 static_assert(sizeof(MacosVersion) == sizeof(atomic_uint32_t::Type),
729               "MacosVersion cache size");
730 static atomic_uint32_t cached_macos_version;
731 
732 MacosVersion 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 
743 DarwinKernelVersion 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 
756 uptr 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 
768 void *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 
779 void internal_join_thread(void *th) { pthread_join((pthread_t)th, 0); }
780 
781 #if !SANITIZER_GO
782 static BlockingMutex syslog_lock(LINKER_INITIALIZED);
783 #endif
784 
785 void 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
797 static char crashreporter_info_buff[__sanitizer::kErrorMessageBufferSize] = {};
798 static BlockingMutex crashreporter_info_mutex(LINKER_INITIALIZED);
799 
800 extern "C" {
801 // Integrate with crash reporter libraries.
802 #if HAVE_CRASHREPORTERCLIENT_H
803 CRASH_REPORTER_CLIENT_HIDDEN
804 struct 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
820 static const char *__crashreporter_info__ __attribute__((__used__)) =
821     &crashreporter_info_buff[0];
822 asm(".desc ___crashreporter_info__, 0x10");
823 #endif
824 
825 }  // extern "C"
826 
827 static void CRAppendCrashLogMessage(const char *msg) {
828   BlockingMutexLock 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 
836 void LogMessageOnPrintf(const char *str) {
837   // Log all printf output to CrashLog.
838   if (common_flags()->abort_on_error)
839     CRAppendCrashLogMessage(str);
840 }
841 
842 void 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   BlockingMutexLock 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 
880 SignalContext::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 #else
885   return UNKNOWN;
886 #endif
887 }
888 
889 bool SignalContext::IsTrueFaultingAddress() const {
890   auto si = static_cast<const siginfo_t *>(siginfo);
891   // "Real" SIGSEGV codes (e.g., SEGV_MAPERR, SEGV_MAPERR) are non-zero.
892   return si->si_signo == SIGSEGV && si->si_code != 0;
893 }
894 
895 #if defined(__aarch64__) && defined(arm_thread_state64_get_sp)
896   #define AARCH64_GET_REG(r) \
897     (uptr)ptrauth_strip(     \
898         (void *)arm_thread_state64_get_##r(ucontext->uc_mcontext->__ss), 0)
899 #else
900   #define AARCH64_GET_REG(r) ucontext->uc_mcontext->__ss.__##r
901 #endif
902 
903 static void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
904   ucontext_t *ucontext = (ucontext_t*)context;
905 # if defined(__aarch64__)
906   *pc = AARCH64_GET_REG(pc);
907 #   if defined(__IPHONE_8_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_8_0
908   *bp = AARCH64_GET_REG(fp);
909 #   else
910   *bp = AARCH64_GET_REG(lr);
911 #   endif
912   *sp = AARCH64_GET_REG(sp);
913 # elif defined(__x86_64__)
914   *pc = ucontext->uc_mcontext->__ss.__rip;
915   *bp = ucontext->uc_mcontext->__ss.__rbp;
916   *sp = ucontext->uc_mcontext->__ss.__rsp;
917 # elif defined(__arm__)
918   *pc = ucontext->uc_mcontext->__ss.__pc;
919   *bp = ucontext->uc_mcontext->__ss.__r[7];
920   *sp = ucontext->uc_mcontext->__ss.__sp;
921 # elif defined(__i386__)
922   *pc = ucontext->uc_mcontext->__ss.__eip;
923   *bp = ucontext->uc_mcontext->__ss.__ebp;
924   *sp = ucontext->uc_mcontext->__ss.__esp;
925 # else
926 # error "Unknown architecture"
927 # endif
928 }
929 
930 void SignalContext::InitPcSpBp() {
931   addr = (uptr)ptrauth_strip((void *)addr, 0);
932   GetPcSpBp(context, &pc, &sp, &bp);
933 }
934 
935 // ASan/TSan use mmap in a way that creates “deallocation gaps” which triggers
936 // EXC_GUARD exceptions on macOS 10.15+ (XNU 19.0+).
937 static void DisableMmapExcGuardExceptions() {
938   using task_exc_guard_behavior_t = uint32_t;
939   using task_set_exc_guard_behavior_t =
940       kern_return_t(task_t task, task_exc_guard_behavior_t behavior);
941   auto *set_behavior = (task_set_exc_guard_behavior_t *)dlsym(
942       RTLD_DEFAULT, "task_set_exc_guard_behavior");
943   if (set_behavior == nullptr) return;
944   const task_exc_guard_behavior_t task_exc_guard_none = 0;
945   set_behavior(mach_task_self(), task_exc_guard_none);
946 }
947 
948 void InitializePlatformEarly() {
949   // Only use xnu_fast_mmap when on x86_64 and the kernel supports it.
950   use_xnu_fast_mmap =
951 #if defined(__x86_64__)
952       GetDarwinKernelVersion() >= DarwinKernelVersion(17, 5);
953 #else
954       false;
955 #endif
956   if (GetDarwinKernelVersion() >= DarwinKernelVersion(19, 0))
957     DisableMmapExcGuardExceptions();
958 }
959 
960 #if !SANITIZER_GO
961 static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES";
962 LowLevelAllocator allocator_for_env;
963 
964 // Change the value of the env var |name|, leaking the original value.
965 // If |name_value| is NULL, the variable is deleted from the environment,
966 // otherwise the corresponding "NAME=value" string is replaced with
967 // |name_value|.
968 void LeakyResetEnv(const char *name, const char *name_value) {
969   char **env = GetEnviron();
970   uptr name_len = internal_strlen(name);
971   while (*env != 0) {
972     uptr len = internal_strlen(*env);
973     if (len > name_len) {
974       const char *p = *env;
975       if (!internal_memcmp(p, name, name_len) && p[name_len] == '=') {
976         // Match.
977         if (name_value) {
978           // Replace the old value with the new one.
979           *env = const_cast<char*>(name_value);
980         } else {
981           // Shift the subsequent pointers back.
982           char **del = env;
983           do {
984             del[0] = del[1];
985           } while (*del++);
986         }
987       }
988     }
989     env++;
990   }
991 }
992 
993 SANITIZER_WEAK_CXX_DEFAULT_IMPL
994 bool ReexecDisabled() {
995   return false;
996 }
997 
998 static bool DyldNeedsEnvVariable() {
999   // If running on OS X 10.11+ or iOS 9.0+, dyld will interpose even if
1000   // DYLD_INSERT_LIBRARIES is not set.
1001   return GetMacosAlignedVersion() < MacosVersion(10, 11);
1002 }
1003 
1004 void MaybeReexec() {
1005   // FIXME: This should really live in some "InitializePlatform" method.
1006   MonotonicNanoTime();
1007 
1008   if (ReexecDisabled()) return;
1009 
1010   // Make sure the dynamic runtime library is preloaded so that the
1011   // wrappers work. If it is not, set DYLD_INSERT_LIBRARIES and re-exec
1012   // ourselves.
1013   Dl_info info;
1014   RAW_CHECK(dladdr((void*)((uptr)&__sanitizer_report_error_summary), &info));
1015   char *dyld_insert_libraries =
1016       const_cast<char*>(GetEnv(kDyldInsertLibraries));
1017   uptr old_env_len = dyld_insert_libraries ?
1018       internal_strlen(dyld_insert_libraries) : 0;
1019   uptr fname_len = internal_strlen(info.dli_fname);
1020   const char *dylib_name = StripModuleName(info.dli_fname);
1021   uptr dylib_name_len = internal_strlen(dylib_name);
1022 
1023   bool lib_is_in_env = dyld_insert_libraries &&
1024                        internal_strstr(dyld_insert_libraries, dylib_name);
1025   if (DyldNeedsEnvVariable() && !lib_is_in_env) {
1026     // DYLD_INSERT_LIBRARIES is not set or does not contain the runtime
1027     // library.
1028     InternalMmapVector<char> program_name(1024);
1029     uint32_t buf_size = program_name.size();
1030     _NSGetExecutablePath(program_name.data(), &buf_size);
1031     char *new_env = const_cast<char*>(info.dli_fname);
1032     if (dyld_insert_libraries) {
1033       // Append the runtime dylib name to the existing value of
1034       // DYLD_INSERT_LIBRARIES.
1035       new_env = (char*)allocator_for_env.Allocate(old_env_len + fname_len + 2);
1036       internal_strncpy(new_env, dyld_insert_libraries, old_env_len);
1037       new_env[old_env_len] = ':';
1038       // Copy fname_len and add a trailing zero.
1039       internal_strncpy(new_env + old_env_len + 1, info.dli_fname,
1040                        fname_len + 1);
1041       // Ok to use setenv() since the wrappers don't depend on the value of
1042       // asan_inited.
1043       setenv(kDyldInsertLibraries, new_env, /*overwrite*/1);
1044     } else {
1045       // Set DYLD_INSERT_LIBRARIES equal to the runtime dylib name.
1046       setenv(kDyldInsertLibraries, info.dli_fname, /*overwrite*/0);
1047     }
1048     VReport(1, "exec()-ing the program with\n");
1049     VReport(1, "%s=%s\n", kDyldInsertLibraries, new_env);
1050     VReport(1, "to enable wrappers.\n");
1051     execv(program_name.data(), *_NSGetArgv());
1052 
1053     // We get here only if execv() failed.
1054     Report("ERROR: The process is launched without DYLD_INSERT_LIBRARIES, "
1055            "which is required for the sanitizer to work. We tried to set the "
1056            "environment variable and re-execute itself, but execv() failed, "
1057            "possibly because of sandbox restrictions. Make sure to launch the "
1058            "executable with:\n%s=%s\n", kDyldInsertLibraries, new_env);
1059     RAW_CHECK("execv failed" && 0);
1060   }
1061 
1062   // Verify that interceptors really work.  We'll use dlsym to locate
1063   // "pthread_create", if interceptors are working, it should really point to
1064   // "wrap_pthread_create" within our own dylib.
1065   Dl_info info_pthread_create;
1066   void *dlopen_addr = dlsym(RTLD_DEFAULT, "pthread_create");
1067   RAW_CHECK(dladdr(dlopen_addr, &info_pthread_create));
1068   if (internal_strcmp(info.dli_fname, info_pthread_create.dli_fname) != 0) {
1069     Report(
1070         "ERROR: Interceptors are not working. This may be because %s is "
1071         "loaded too late (e.g. via dlopen). Please launch the executable "
1072         "with:\n%s=%s\n",
1073         SanitizerToolName, kDyldInsertLibraries, info.dli_fname);
1074     RAW_CHECK("interceptors not installed" && 0);
1075   }
1076 
1077   if (!lib_is_in_env)
1078     return;
1079 
1080   if (!common_flags()->strip_env)
1081     return;
1082 
1083   // DYLD_INSERT_LIBRARIES is set and contains the runtime library. Let's remove
1084   // the dylib from the environment variable, because interceptors are installed
1085   // and we don't want our children to inherit the variable.
1086 
1087   uptr env_name_len = internal_strlen(kDyldInsertLibraries);
1088   // Allocate memory to hold the previous env var name, its value, the '='
1089   // sign and the '\0' char.
1090   char *new_env = (char*)allocator_for_env.Allocate(
1091       old_env_len + 2 + env_name_len);
1092   RAW_CHECK(new_env);
1093   internal_memset(new_env, '\0', old_env_len + 2 + env_name_len);
1094   internal_strncpy(new_env, kDyldInsertLibraries, env_name_len);
1095   new_env[env_name_len] = '=';
1096   char *new_env_pos = new_env + env_name_len + 1;
1097 
1098   // Iterate over colon-separated pieces of |dyld_insert_libraries|.
1099   char *piece_start = dyld_insert_libraries;
1100   char *piece_end = NULL;
1101   char *old_env_end = dyld_insert_libraries + old_env_len;
1102   do {
1103     if (piece_start[0] == ':') piece_start++;
1104     piece_end = internal_strchr(piece_start, ':');
1105     if (!piece_end) piece_end = dyld_insert_libraries + old_env_len;
1106     if ((uptr)(piece_start - dyld_insert_libraries) > old_env_len) break;
1107     uptr piece_len = piece_end - piece_start;
1108 
1109     char *filename_start =
1110         (char *)internal_memrchr(piece_start, '/', piece_len);
1111     uptr filename_len = piece_len;
1112     if (filename_start) {
1113       filename_start += 1;
1114       filename_len = piece_len - (filename_start - piece_start);
1115     } else {
1116       filename_start = piece_start;
1117     }
1118 
1119     // If the current piece isn't the runtime library name,
1120     // append it to new_env.
1121     if ((dylib_name_len != filename_len) ||
1122         (internal_memcmp(filename_start, dylib_name, dylib_name_len) != 0)) {
1123       if (new_env_pos != new_env + env_name_len + 1) {
1124         new_env_pos[0] = ':';
1125         new_env_pos++;
1126       }
1127       internal_strncpy(new_env_pos, piece_start, piece_len);
1128       new_env_pos += piece_len;
1129     }
1130     // Move on to the next piece.
1131     piece_start = piece_end;
1132   } while (piece_start < old_env_end);
1133 
1134   // Can't use setenv() here, because it requires the allocator to be
1135   // initialized.
1136   // FIXME: instead of filtering DYLD_INSERT_LIBRARIES here, do it in
1137   // a separate function called after InitializeAllocator().
1138   if (new_env_pos == new_env + env_name_len + 1) new_env = NULL;
1139   LeakyResetEnv(kDyldInsertLibraries, new_env);
1140 }
1141 #endif  // SANITIZER_GO
1142 
1143 char **GetArgv() {
1144   return *_NSGetArgv();
1145 }
1146 
1147 #if SANITIZER_IOS && !SANITIZER_IOSSIM
1148 // The task_vm_info struct is normally provided by the macOS SDK, but we need
1149 // fields only available in 10.12+. Declare the struct manually to be able to
1150 // build against older SDKs.
1151 struct __sanitizer_task_vm_info {
1152   mach_vm_size_t virtual_size;
1153   integer_t region_count;
1154   integer_t page_size;
1155   mach_vm_size_t resident_size;
1156   mach_vm_size_t resident_size_peak;
1157   mach_vm_size_t device;
1158   mach_vm_size_t device_peak;
1159   mach_vm_size_t internal;
1160   mach_vm_size_t internal_peak;
1161   mach_vm_size_t external;
1162   mach_vm_size_t external_peak;
1163   mach_vm_size_t reusable;
1164   mach_vm_size_t reusable_peak;
1165   mach_vm_size_t purgeable_volatile_pmap;
1166   mach_vm_size_t purgeable_volatile_resident;
1167   mach_vm_size_t purgeable_volatile_virtual;
1168   mach_vm_size_t compressed;
1169   mach_vm_size_t compressed_peak;
1170   mach_vm_size_t compressed_lifetime;
1171   mach_vm_size_t phys_footprint;
1172   mach_vm_address_t min_address;
1173   mach_vm_address_t max_address;
1174 };
1175 #define __SANITIZER_TASK_VM_INFO_COUNT ((mach_msg_type_number_t) \
1176     (sizeof(__sanitizer_task_vm_info) / sizeof(natural_t)))
1177 
1178 static uptr GetTaskInfoMaxAddress() {
1179   __sanitizer_task_vm_info vm_info = {} /* zero initialize */;
1180   mach_msg_type_number_t count = __SANITIZER_TASK_VM_INFO_COUNT;
1181   int err = task_info(mach_task_self(), TASK_VM_INFO, (int *)&vm_info, &count);
1182   return err ? 0 : vm_info.max_address;
1183 }
1184 
1185 uptr GetMaxUserVirtualAddress() {
1186   static uptr max_vm = GetTaskInfoMaxAddress();
1187   if (max_vm != 0) {
1188     const uptr ret_value = max_vm - 1;
1189     CHECK_LE(ret_value, SANITIZER_MMAP_RANGE_SIZE);
1190     return ret_value;
1191   }
1192 
1193   // xnu cannot provide vm address limit
1194 # if SANITIZER_WORDSIZE == 32
1195   constexpr uptr fallback_max_vm = 0xffe00000 - 1;
1196 # else
1197   constexpr uptr fallback_max_vm = 0x200000000 - 1;
1198 # endif
1199   static_assert(fallback_max_vm <= SANITIZER_MMAP_RANGE_SIZE,
1200                 "Max virtual address must be less than mmap range size.");
1201   return fallback_max_vm;
1202 }
1203 
1204 #else // !SANITIZER_IOS
1205 
1206 uptr GetMaxUserVirtualAddress() {
1207 # if SANITIZER_WORDSIZE == 64
1208   constexpr uptr max_vm = (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
1209 # else // SANITIZER_WORDSIZE == 32
1210   static_assert(SANITIZER_WORDSIZE == 32, "Wrong wordsize");
1211   constexpr uptr max_vm = (1ULL << 32) - 1;  // 0xffffffff;
1212 # endif
1213   static_assert(max_vm <= SANITIZER_MMAP_RANGE_SIZE,
1214                 "Max virtual address must be less than mmap range size.");
1215   return max_vm;
1216 }
1217 #endif
1218 
1219 uptr GetMaxVirtualAddress() {
1220   return GetMaxUserVirtualAddress();
1221 }
1222 
1223 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
1224                       uptr min_shadow_base_alignment, uptr &high_mem_end) {
1225   const uptr granularity = GetMmapGranularity();
1226   const uptr alignment =
1227       Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
1228   const uptr left_padding =
1229       Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);
1230 
1231   uptr space_size = shadow_size_bytes + left_padding;
1232 
1233   uptr largest_gap_found = 0;
1234   uptr max_occupied_addr = 0;
1235   VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
1236   uptr shadow_start =
1237       FindAvailableMemoryRange(space_size, alignment, granularity,
1238                                &largest_gap_found, &max_occupied_addr);
1239   // If the shadow doesn't fit, restrict the address space to make it fit.
1240   if (shadow_start == 0) {
1241     VReport(
1242         2,
1243         "Shadow doesn't fit, largest_gap_found = %p, max_occupied_addr = %p\n",
1244         largest_gap_found, max_occupied_addr);
1245     uptr new_max_vm = RoundDownTo(largest_gap_found << shadow_scale, alignment);
1246     if (new_max_vm < max_occupied_addr) {
1247       Report("Unable to find a memory range for dynamic shadow.\n");
1248       Report(
1249           "space_size = %p, largest_gap_found = %p, max_occupied_addr = %p, "
1250           "new_max_vm = %p\n",
1251           space_size, largest_gap_found, max_occupied_addr, new_max_vm);
1252       CHECK(0 && "cannot place shadow");
1253     }
1254     RestrictMemoryToMaxAddress(new_max_vm);
1255     high_mem_end = new_max_vm - 1;
1256     space_size = (high_mem_end >> shadow_scale) + left_padding;
1257     VReport(2, "FindDynamicShadowStart, space_size = %p\n", space_size);
1258     shadow_start = FindAvailableMemoryRange(space_size, alignment, granularity,
1259                                             nullptr, nullptr);
1260     if (shadow_start == 0) {
1261       Report("Unable to find a memory range after restricting VM.\n");
1262       CHECK(0 && "cannot place shadow after restricting vm");
1263     }
1264   }
1265   CHECK_NE((uptr)0, shadow_start);
1266   CHECK(IsAligned(shadow_start, alignment));
1267   return shadow_start;
1268 }
1269 
1270 uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
1271                                 uptr num_aliases, uptr ring_buffer_size) {
1272   CHECK(false && "HWASan aliasing is unimplemented on Mac");
1273   return 0;
1274 }
1275 
1276 uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
1277                               uptr *largest_gap_found,
1278                               uptr *max_occupied_addr) {
1279   typedef vm_region_submap_short_info_data_64_t RegionInfo;
1280   enum { kRegionInfoSize = VM_REGION_SUBMAP_SHORT_INFO_COUNT_64 };
1281   // Start searching for available memory region past PAGEZERO, which is
1282   // 4KB on 32-bit and 4GB on 64-bit.
1283   mach_vm_address_t start_address =
1284     (SANITIZER_WORDSIZE == 32) ? 0x000000001000 : 0x000100000000;
1285 
1286   mach_vm_address_t address = start_address;
1287   mach_vm_address_t free_begin = start_address;
1288   kern_return_t kr = KERN_SUCCESS;
1289   if (largest_gap_found) *largest_gap_found = 0;
1290   if (max_occupied_addr) *max_occupied_addr = 0;
1291   while (kr == KERN_SUCCESS) {
1292     mach_vm_size_t vmsize = 0;
1293     natural_t depth = 0;
1294     RegionInfo vminfo;
1295     mach_msg_type_number_t count = kRegionInfoSize;
1296     kr = mach_vm_region_recurse(mach_task_self(), &address, &vmsize, &depth,
1297                                 (vm_region_info_t)&vminfo, &count);
1298     if (kr == KERN_INVALID_ADDRESS) {
1299       // No more regions beyond "address", consider the gap at the end of VM.
1300       address = GetMaxVirtualAddress() + 1;
1301       vmsize = 0;
1302     } else {
1303       if (max_occupied_addr) *max_occupied_addr = address + vmsize;
1304     }
1305     if (free_begin != address) {
1306       // We found a free region [free_begin..address-1].
1307       uptr gap_start = RoundUpTo((uptr)free_begin + left_padding, alignment);
1308       uptr gap_end = RoundDownTo((uptr)address, alignment);
1309       uptr gap_size = gap_end > gap_start ? gap_end - gap_start : 0;
1310       if (size < gap_size) {
1311         return gap_start;
1312       }
1313 
1314       if (largest_gap_found && *largest_gap_found < gap_size) {
1315         *largest_gap_found = gap_size;
1316       }
1317     }
1318     // Move to the next region.
1319     address += vmsize;
1320     free_begin = address;
1321   }
1322 
1323   // We looked at all free regions and could not find one large enough.
1324   return 0;
1325 }
1326 
1327 // FIXME implement on this platform.
1328 void GetMemoryProfile(fill_profile_f cb, uptr *stats, uptr stats_size) { }
1329 
1330 void SignalContext::DumpAllRegisters(void *context) {
1331   Report("Register values:\n");
1332 
1333   ucontext_t *ucontext = (ucontext_t*)context;
1334 # define DUMPREG64(r) \
1335     Printf("%s = 0x%016llx  ", #r, ucontext->uc_mcontext->__ss.__ ## r);
1336 # define DUMPREGA64(r) \
1337     Printf("   %s = 0x%016llx  ", #r, AARCH64_GET_REG(r));
1338 # define DUMPREG32(r) \
1339     Printf("%s = 0x%08x  ", #r, ucontext->uc_mcontext->__ss.__ ## r);
1340 # define DUMPREG_(r)   Printf(" "); DUMPREG(r);
1341 # define DUMPREG__(r)  Printf("  "); DUMPREG(r);
1342 # define DUMPREG___(r) Printf("   "); DUMPREG(r);
1343 
1344 # if defined(__x86_64__)
1345 #  define DUMPREG(r) DUMPREG64(r)
1346   DUMPREG(rax); DUMPREG(rbx); DUMPREG(rcx); DUMPREG(rdx); Printf("\n");
1347   DUMPREG(rdi); DUMPREG(rsi); DUMPREG(rbp); DUMPREG(rsp); Printf("\n");
1348   DUMPREG_(r8); DUMPREG_(r9); DUMPREG(r10); DUMPREG(r11); Printf("\n");
1349   DUMPREG(r12); DUMPREG(r13); DUMPREG(r14); DUMPREG(r15); Printf("\n");
1350 # elif defined(__i386__)
1351 #  define DUMPREG(r) DUMPREG32(r)
1352   DUMPREG(eax); DUMPREG(ebx); DUMPREG(ecx); DUMPREG(edx); Printf("\n");
1353   DUMPREG(edi); DUMPREG(esi); DUMPREG(ebp); DUMPREG(esp); Printf("\n");
1354 # elif defined(__aarch64__)
1355 #  define DUMPREG(r) DUMPREG64(r)
1356   DUMPREG_(x[0]); DUMPREG_(x[1]); DUMPREG_(x[2]); DUMPREG_(x[3]); Printf("\n");
1357   DUMPREG_(x[4]); DUMPREG_(x[5]); DUMPREG_(x[6]); DUMPREG_(x[7]); Printf("\n");
1358   DUMPREG_(x[8]); DUMPREG_(x[9]); DUMPREG(x[10]); DUMPREG(x[11]); Printf("\n");
1359   DUMPREG(x[12]); DUMPREG(x[13]); DUMPREG(x[14]); DUMPREG(x[15]); Printf("\n");
1360   DUMPREG(x[16]); DUMPREG(x[17]); DUMPREG(x[18]); DUMPREG(x[19]); Printf("\n");
1361   DUMPREG(x[20]); DUMPREG(x[21]); DUMPREG(x[22]); DUMPREG(x[23]); Printf("\n");
1362   DUMPREG(x[24]); DUMPREG(x[25]); DUMPREG(x[26]); DUMPREG(x[27]); Printf("\n");
1363   DUMPREG(x[28]); DUMPREGA64(fp); DUMPREGA64(lr); DUMPREGA64(sp); Printf("\n");
1364 # elif defined(__arm__)
1365 #  define DUMPREG(r) DUMPREG32(r)
1366   DUMPREG_(r[0]); DUMPREG_(r[1]); DUMPREG_(r[2]); DUMPREG_(r[3]); Printf("\n");
1367   DUMPREG_(r[4]); DUMPREG_(r[5]); DUMPREG_(r[6]); DUMPREG_(r[7]); Printf("\n");
1368   DUMPREG_(r[8]); DUMPREG_(r[9]); DUMPREG(r[10]); DUMPREG(r[11]); Printf("\n");
1369   DUMPREG(r[12]); DUMPREG___(sp); DUMPREG___(lr); DUMPREG___(pc); Printf("\n");
1370 # else
1371 # error "Unknown architecture"
1372 # endif
1373 
1374 # undef DUMPREG64
1375 # undef DUMPREG32
1376 # undef DUMPREG_
1377 # undef DUMPREG__
1378 # undef DUMPREG___
1379 # undef DUMPREG
1380 }
1381 
1382 static inline bool CompareBaseAddress(const LoadedModule &a,
1383                                       const LoadedModule &b) {
1384   return a.base_address() < b.base_address();
1385 }
1386 
1387 void FormatUUID(char *out, uptr size, const u8 *uuid) {
1388   internal_snprintf(out, size,
1389                     "<%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-"
1390                     "%02X%02X%02X%02X%02X%02X>",
1391                     uuid[0], uuid[1], uuid[2], uuid[3], uuid[4], uuid[5],
1392                     uuid[6], uuid[7], uuid[8], uuid[9], uuid[10], uuid[11],
1393                     uuid[12], uuid[13], uuid[14], uuid[15]);
1394 }
1395 
1396 void DumpProcessMap() {
1397   Printf("Process module map:\n");
1398   MemoryMappingLayout memory_mapping(false);
1399   InternalMmapVector<LoadedModule> modules;
1400   modules.reserve(128);
1401   memory_mapping.DumpListOfModules(&modules);
1402   Sort(modules.data(), modules.size(), CompareBaseAddress);
1403   for (uptr i = 0; i < modules.size(); ++i) {
1404     char uuid_str[128];
1405     FormatUUID(uuid_str, sizeof(uuid_str), modules[i].uuid());
1406     Printf("0x%zx-0x%zx %s (%s) %s\n", modules[i].base_address(),
1407            modules[i].max_executable_address(), modules[i].full_name(),
1408            ModuleArchToString(modules[i].arch()), uuid_str);
1409   }
1410   Printf("End of module map.\n");
1411 }
1412 
1413 void CheckNoDeepBind(const char *filename, int flag) {
1414   // Do nothing.
1415 }
1416 
1417 bool GetRandom(void *buffer, uptr length, bool blocking) {
1418   if (!buffer || !length || length > 256)
1419     return false;
1420   // arc4random never fails.
1421   REAL(arc4random_buf)(buffer, length);
1422   return true;
1423 }
1424 
1425 u32 GetNumberOfCPUs() {
1426   return (u32)sysconf(_SC_NPROCESSORS_ONLN);
1427 }
1428 
1429 void InitializePlatformCommonFlags(CommonFlags *cf) {}
1430 
1431 }  // namespace __sanitizer
1432 
1433 #endif  // SANITIZER_MAC
1434