xref: /freebsd/contrib/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp (revision a0ca4af9455b844c5e094fc1b09b1390ffa979fc)
1 //===-- sanitizer_linux.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 AddressSanitizer and ThreadSanitizer
10 // run-time libraries and implements linux-specific functions from
11 // sanitizer_libc.h.
12 //===----------------------------------------------------------------------===//
13 
14 #include "sanitizer_platform.h"
15 
16 #if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
17     SANITIZER_SOLARIS
18 
19 #  include "sanitizer_common.h"
20 #  include "sanitizer_flags.h"
21 #  include "sanitizer_getauxval.h"
22 #  include "sanitizer_internal_defs.h"
23 #  include "sanitizer_libc.h"
24 #  include "sanitizer_linux.h"
25 #  include "sanitizer_mutex.h"
26 #  include "sanitizer_placement_new.h"
27 #  include "sanitizer_procmaps.h"
28 
29 #  if SANITIZER_LINUX && !SANITIZER_GO
30 #    include <asm/param.h>
31 #  endif
32 
33 // For mips64, syscall(__NR_stat) fills the buffer in the 'struct kernel_stat'
34 // format. Struct kernel_stat is defined as 'struct stat' in asm/stat.h. To
35 // access stat from asm/stat.h, without conflicting with definition in
36 // sys/stat.h, we use this trick.
37 #  if SANITIZER_MIPS64
38 #    include <asm/unistd.h>
39 #    include <sys/types.h>
40 #    define stat kernel_stat
41 #    if SANITIZER_GO
42 #      undef st_atime
43 #      undef st_mtime
44 #      undef st_ctime
45 #      define st_atime st_atim
46 #      define st_mtime st_mtim
47 #      define st_ctime st_ctim
48 #    endif
49 #    include <asm/stat.h>
50 #    undef stat
51 #  endif
52 
53 #  include <dlfcn.h>
54 #  include <errno.h>
55 #  include <fcntl.h>
56 #  include <link.h>
57 #  include <pthread.h>
58 #  include <sched.h>
59 #  include <signal.h>
60 #  include <sys/mman.h>
61 #  if !SANITIZER_SOLARIS
62 #    include <sys/ptrace.h>
63 #  endif
64 #  include <sys/resource.h>
65 #  include <sys/stat.h>
66 #  include <sys/syscall.h>
67 #  include <sys/time.h>
68 #  include <sys/types.h>
69 #  include <ucontext.h>
70 #  include <unistd.h>
71 
72 #  if SANITIZER_LINUX
73 #    include <sys/utsname.h>
74 #  endif
75 
76 #  if SANITIZER_LINUX && !SANITIZER_ANDROID
77 #    include <sys/personality.h>
78 #  endif
79 
80 #  if SANITIZER_LINUX && defined(__loongarch__)
81 #    include <sys/sysmacros.h>
82 #  endif
83 
84 #  if SANITIZER_FREEBSD
85 #    include <machine/atomic.h>
86 #    include <sys/exec.h>
87 #    include <sys/procctl.h>
88 #    include <sys/sysctl.h>
89 extern "C" {
90 // <sys/umtx.h> must be included after <errno.h> and <sys/types.h> on
91 // FreeBSD 9.2 and 10.0.
92 #    include <sys/umtx.h>
93 }
94 #    include <sys/thr.h>
95 #  endif  // SANITIZER_FREEBSD
96 
97 #  if SANITIZER_NETBSD
98 #    include <limits.h>  // For NAME_MAX
99 #    include <sys/exec.h>
100 #    include <sys/sysctl.h>
101 extern struct ps_strings *__ps_strings;
102 #  endif  // SANITIZER_NETBSD
103 
104 #  if SANITIZER_SOLARIS
105 #    include <stdlib.h>
106 #    include <thread.h>
107 #    define environ _environ
108 #  endif
109 
110 extern char **environ;
111 
112 #  if SANITIZER_LINUX
113 // <linux/time.h>
114 struct kernel_timeval {
115   long tv_sec;
116   long tv_usec;
117 };
118 
119 // <linux/futex.h> is broken on some linux distributions.
120 const int FUTEX_WAIT = 0;
121 const int FUTEX_WAKE = 1;
122 const int FUTEX_PRIVATE_FLAG = 128;
123 const int FUTEX_WAIT_PRIVATE = FUTEX_WAIT | FUTEX_PRIVATE_FLAG;
124 const int FUTEX_WAKE_PRIVATE = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
125 #  endif  // SANITIZER_LINUX
126 
127 // Are we using 32-bit or 64-bit Linux syscalls?
128 // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
129 // but it still needs to use 64-bit syscalls.
130 #  if SANITIZER_LINUX && (defined(__x86_64__) || defined(__powerpc64__) || \
131                           SANITIZER_WORDSIZE == 64 ||                      \
132                           (defined(__mips__) && _MIPS_SIM == _ABIN32))
133 #    define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
134 #  else
135 #    define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
136 #  endif
137 
138 // Note : FreeBSD implemented both Linux and OpenBSD apis.
139 #  if SANITIZER_LINUX && defined(__NR_getrandom)
140 #    if !defined(GRND_NONBLOCK)
141 #      define GRND_NONBLOCK 1
142 #    endif
143 #    define SANITIZER_USE_GETRANDOM 1
144 #  else
145 #    define SANITIZER_USE_GETRANDOM 0
146 #  endif  // SANITIZER_LINUX && defined(__NR_getrandom)
147 
148 #  if SANITIZER_FREEBSD
149 #    define SANITIZER_USE_GETENTROPY 1
150 #  endif
151 
152 namespace __sanitizer {
153 
154 void SetSigProcMask(__sanitizer_sigset_t *set, __sanitizer_sigset_t *oldset) {
155   CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, set, oldset));
156 }
157 
158 void BlockSignals(__sanitizer_sigset_t *oldset) {
159   __sanitizer_sigset_t set;
160   internal_sigfillset(&set);
161 #  if SANITIZER_LINUX && !SANITIZER_ANDROID
162   // Glibc uses SIGSETXID signal during setuid call. If this signal is blocked
163   // on any thread, setuid call hangs.
164   // See test/sanitizer_common/TestCases/Linux/setuid.c.
165   internal_sigdelset(&set, 33);
166 #  endif
167 #  if SANITIZER_LINUX
168   // Seccomp-BPF-sandboxed processes rely on SIGSYS to handle trapped syscalls.
169   // If this signal is blocked, such calls cannot be handled and the process may
170   // hang.
171   internal_sigdelset(&set, 31);
172 #  endif
173   SetSigProcMask(&set, oldset);
174 }
175 
176 ScopedBlockSignals::ScopedBlockSignals(__sanitizer_sigset_t *copy) {
177   BlockSignals(&saved_);
178   if (copy)
179     internal_memcpy(copy, &saved_, sizeof(saved_));
180 }
181 
182 ScopedBlockSignals::~ScopedBlockSignals() { SetSigProcMask(&saved_, nullptr); }
183 
184 #  if SANITIZER_LINUX && defined(__x86_64__)
185 #    include "sanitizer_syscall_linux_x86_64.inc"
186 #  elif SANITIZER_LINUX && SANITIZER_RISCV64
187 #    include "sanitizer_syscall_linux_riscv64.inc"
188 #  elif SANITIZER_LINUX && defined(__aarch64__)
189 #    include "sanitizer_syscall_linux_aarch64.inc"
190 #  elif SANITIZER_LINUX && defined(__arm__)
191 #    include "sanitizer_syscall_linux_arm.inc"
192 #  elif SANITIZER_LINUX && defined(__hexagon__)
193 #    include "sanitizer_syscall_linux_hexagon.inc"
194 #  elif SANITIZER_LINUX && SANITIZER_LOONGARCH64
195 #    include "sanitizer_syscall_linux_loongarch64.inc"
196 #  else
197 #    include "sanitizer_syscall_generic.inc"
198 #  endif
199 
200 // --------------- sanitizer_libc.h
201 #  if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
202 #    if !SANITIZER_S390
203 uptr internal_mmap(void *addr, uptr length, int prot, int flags, int fd,
204                    u64 offset) {
205 #      if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
206   return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
207                           offset);
208 #      else
209   // mmap2 specifies file offset in 4096-byte units.
210   CHECK(IsAligned(offset, 4096));
211   return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
212                           offset / 4096);
213 #      endif
214 }
215 #    endif  // !SANITIZER_S390
216 
217 uptr internal_munmap(void *addr, uptr length) {
218   return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
219 }
220 
221 #    if SANITIZER_LINUX
222 uptr internal_mremap(void *old_address, uptr old_size, uptr new_size, int flags,
223                      void *new_address) {
224   return internal_syscall(SYSCALL(mremap), (uptr)old_address, old_size,
225                           new_size, flags, (uptr)new_address);
226 }
227 #    endif
228 
229 int internal_mprotect(void *addr, uptr length, int prot) {
230   return internal_syscall(SYSCALL(mprotect), (uptr)addr, length, prot);
231 }
232 
233 int internal_madvise(uptr addr, uptr length, int advice) {
234   return internal_syscall(SYSCALL(madvise), addr, length, advice);
235 }
236 
237 uptr internal_close(fd_t fd) { return internal_syscall(SYSCALL(close), fd); }
238 
239 uptr internal_open(const char *filename, int flags) {
240 #    if SANITIZER_LINUX
241   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags);
242 #    else
243   return internal_syscall(SYSCALL(open), (uptr)filename, flags);
244 #    endif
245 }
246 
247 uptr internal_open(const char *filename, int flags, u32 mode) {
248 #    if SANITIZER_LINUX
249   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags,
250                           mode);
251 #    else
252   return internal_syscall(SYSCALL(open), (uptr)filename, flags, mode);
253 #    endif
254 }
255 
256 uptr internal_read(fd_t fd, void *buf, uptr count) {
257   sptr res;
258   HANDLE_EINTR(res,
259                (sptr)internal_syscall(SYSCALL(read), fd, (uptr)buf, count));
260   return res;
261 }
262 
263 uptr internal_write(fd_t fd, const void *buf, uptr count) {
264   sptr res;
265   HANDLE_EINTR(res,
266                (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf, count));
267   return res;
268 }
269 
270 uptr internal_ftruncate(fd_t fd, uptr size) {
271   sptr res;
272   HANDLE_EINTR(res,
273                (sptr)internal_syscall(SYSCALL(ftruncate), fd, (OFF_T)size));
274   return res;
275 }
276 
277 #    if (!SANITIZER_LINUX_USES_64BIT_SYSCALLS || SANITIZER_SPARC) && \
278         SANITIZER_LINUX
279 static void stat64_to_stat(struct stat64 *in, struct stat *out) {
280   internal_memset(out, 0, sizeof(*out));
281   out->st_dev = in->st_dev;
282   out->st_ino = in->st_ino;
283   out->st_mode = in->st_mode;
284   out->st_nlink = in->st_nlink;
285   out->st_uid = in->st_uid;
286   out->st_gid = in->st_gid;
287   out->st_rdev = in->st_rdev;
288   out->st_size = in->st_size;
289   out->st_blksize = in->st_blksize;
290   out->st_blocks = in->st_blocks;
291   out->st_atime = in->st_atime;
292   out->st_mtime = in->st_mtime;
293   out->st_ctime = in->st_ctime;
294 }
295 #    endif
296 
297 #    if SANITIZER_LINUX && defined(__loongarch__)
298 static void statx_to_stat(struct statx *in, struct stat *out) {
299   internal_memset(out, 0, sizeof(*out));
300   out->st_dev = makedev(in->stx_dev_major, in->stx_dev_minor);
301   out->st_ino = in->stx_ino;
302   out->st_mode = in->stx_mode;
303   out->st_nlink = in->stx_nlink;
304   out->st_uid = in->stx_uid;
305   out->st_gid = in->stx_gid;
306   out->st_rdev = makedev(in->stx_rdev_major, in->stx_rdev_minor);
307   out->st_size = in->stx_size;
308   out->st_blksize = in->stx_blksize;
309   out->st_blocks = in->stx_blocks;
310   out->st_atime = in->stx_atime.tv_sec;
311   out->st_atim.tv_nsec = in->stx_atime.tv_nsec;
312   out->st_mtime = in->stx_mtime.tv_sec;
313   out->st_mtim.tv_nsec = in->stx_mtime.tv_nsec;
314   out->st_ctime = in->stx_ctime.tv_sec;
315   out->st_ctim.tv_nsec = in->stx_ctime.tv_nsec;
316 }
317 #    endif
318 
319 #    if SANITIZER_MIPS64
320 // Undefine compatibility macros from <sys/stat.h>
321 // so that they would not clash with the kernel_stat
322 // st_[a|m|c]time fields
323 #      if !SANITIZER_GO
324 #        undef st_atime
325 #        undef st_mtime
326 #        undef st_ctime
327 #      endif
328 #      if defined(SANITIZER_ANDROID)
329 // Bionic sys/stat.h defines additional macros
330 // for compatibility with the old NDKs and
331 // they clash with the kernel_stat structure
332 // st_[a|m|c]time_nsec fields.
333 #        undef st_atime_nsec
334 #        undef st_mtime_nsec
335 #        undef st_ctime_nsec
336 #      endif
337 static void kernel_stat_to_stat(struct kernel_stat *in, struct stat *out) {
338   internal_memset(out, 0, sizeof(*out));
339   out->st_dev = in->st_dev;
340   out->st_ino = in->st_ino;
341   out->st_mode = in->st_mode;
342   out->st_nlink = in->st_nlink;
343   out->st_uid = in->st_uid;
344   out->st_gid = in->st_gid;
345   out->st_rdev = in->st_rdev;
346   out->st_size = in->st_size;
347   out->st_blksize = in->st_blksize;
348   out->st_blocks = in->st_blocks;
349 #      if defined(__USE_MISC) || defined(__USE_XOPEN2K8) || \
350           defined(SANITIZER_ANDROID)
351   out->st_atim.tv_sec = in->st_atime;
352   out->st_atim.tv_nsec = in->st_atime_nsec;
353   out->st_mtim.tv_sec = in->st_mtime;
354   out->st_mtim.tv_nsec = in->st_mtime_nsec;
355   out->st_ctim.tv_sec = in->st_ctime;
356   out->st_ctim.tv_nsec = in->st_ctime_nsec;
357 #      else
358   out->st_atime = in->st_atime;
359   out->st_atimensec = in->st_atime_nsec;
360   out->st_mtime = in->st_mtime;
361   out->st_mtimensec = in->st_mtime_nsec;
362   out->st_ctime = in->st_ctime;
363   out->st_atimensec = in->st_ctime_nsec;
364 #      endif
365 }
366 #    endif
367 
368 uptr internal_stat(const char *path, void *buf) {
369 #    if SANITIZER_FREEBSD
370   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf, 0);
371 #    elif SANITIZER_LINUX
372 #      if defined(__loongarch__)
373   struct statx bufx;
374   int res = internal_syscall(SYSCALL(statx), AT_FDCWD, (uptr)path,
375                              AT_NO_AUTOMOUNT, STATX_BASIC_STATS, (uptr)&bufx);
376   statx_to_stat(&bufx, (struct stat *)buf);
377   return res;
378 #      elif (SANITIZER_WORDSIZE == 64 || SANITIZER_X32 ||    \
379              (defined(__mips__) && _MIPS_SIM == _ABIN32)) && \
380           !SANITIZER_SPARC
381   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
382                           0);
383 #      else
384   struct stat64 buf64;
385   int res = internal_syscall(SYSCALL(fstatat64), AT_FDCWD, (uptr)path,
386                              (uptr)&buf64, 0);
387   stat64_to_stat(&buf64, (struct stat *)buf);
388   return res;
389 #      endif
390 #    else
391   struct stat64 buf64;
392   int res = internal_syscall(SYSCALL(stat64), path, &buf64);
393   stat64_to_stat(&buf64, (struct stat *)buf);
394   return res;
395 #    endif
396 }
397 
398 uptr internal_lstat(const char *path, void *buf) {
399 #    if SANITIZER_FREEBSD
400   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf,
401                           AT_SYMLINK_NOFOLLOW);
402 #    elif SANITIZER_LINUX
403 #      if defined(__loongarch__)
404   struct statx bufx;
405   int res = internal_syscall(SYSCALL(statx), AT_FDCWD, (uptr)path,
406                              AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT,
407                              STATX_BASIC_STATS, (uptr)&bufx);
408   statx_to_stat(&bufx, (struct stat *)buf);
409   return res;
410 #      elif (defined(_LP64) || SANITIZER_X32 ||              \
411              (defined(__mips__) && _MIPS_SIM == _ABIN32)) && \
412           !SANITIZER_SPARC
413   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
414                           AT_SYMLINK_NOFOLLOW);
415 #      else
416   struct stat64 buf64;
417   int res = internal_syscall(SYSCALL(fstatat64), AT_FDCWD, (uptr)path,
418                              (uptr)&buf64, AT_SYMLINK_NOFOLLOW);
419   stat64_to_stat(&buf64, (struct stat *)buf);
420   return res;
421 #      endif
422 #    else
423   struct stat64 buf64;
424   int res = internal_syscall(SYSCALL(lstat64), path, &buf64);
425   stat64_to_stat(&buf64, (struct stat *)buf);
426   return res;
427 #    endif
428 }
429 
430 uptr internal_fstat(fd_t fd, void *buf) {
431 #    if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
432 #      if SANITIZER_MIPS64
433   // For mips64, fstat syscall fills buffer in the format of kernel_stat
434   struct kernel_stat kbuf;
435   int res = internal_syscall(SYSCALL(fstat), fd, &kbuf);
436   kernel_stat_to_stat(&kbuf, (struct stat *)buf);
437   return res;
438 #      elif SANITIZER_LINUX && defined(__loongarch__)
439   struct statx bufx;
440   int res = internal_syscall(SYSCALL(statx), fd, "", AT_EMPTY_PATH,
441                              STATX_BASIC_STATS, (uptr)&bufx);
442   statx_to_stat(&bufx, (struct stat *)buf);
443   return res;
444 #      else
445   return internal_syscall(SYSCALL(fstat), fd, (uptr)buf);
446 #      endif
447 #    else
448   struct stat64 buf64;
449   int res = internal_syscall(SYSCALL(fstat64), fd, &buf64);
450   stat64_to_stat(&buf64, (struct stat *)buf);
451   return res;
452 #    endif
453 }
454 
455 uptr internal_filesize(fd_t fd) {
456   struct stat st;
457   if (internal_fstat(fd, &st))
458     return -1;
459   return (uptr)st.st_size;
460 }
461 
462 uptr internal_dup(int oldfd) { return internal_syscall(SYSCALL(dup), oldfd); }
463 
464 uptr internal_dup2(int oldfd, int newfd) {
465 #    if SANITIZER_LINUX
466   return internal_syscall(SYSCALL(dup3), oldfd, newfd, 0);
467 #    else
468   return internal_syscall(SYSCALL(dup2), oldfd, newfd);
469 #    endif
470 }
471 
472 uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
473 #    if SANITIZER_LINUX
474   return internal_syscall(SYSCALL(readlinkat), AT_FDCWD, (uptr)path, (uptr)buf,
475                           bufsize);
476 #    else
477   return internal_syscall(SYSCALL(readlink), (uptr)path, (uptr)buf, bufsize);
478 #    endif
479 }
480 
481 uptr internal_unlink(const char *path) {
482 #    if SANITIZER_LINUX
483   return internal_syscall(SYSCALL(unlinkat), AT_FDCWD, (uptr)path, 0);
484 #    else
485   return internal_syscall(SYSCALL(unlink), (uptr)path);
486 #    endif
487 }
488 
489 uptr internal_rename(const char *oldpath, const char *newpath) {
490 #    if (defined(__riscv) || defined(__loongarch__)) && defined(__linux__)
491   return internal_syscall(SYSCALL(renameat2), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
492                           (uptr)newpath, 0);
493 #    elif SANITIZER_LINUX
494   return internal_syscall(SYSCALL(renameat), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
495                           (uptr)newpath);
496 #    else
497   return internal_syscall(SYSCALL(rename), (uptr)oldpath, (uptr)newpath);
498 #    endif
499 }
500 
501 uptr internal_sched_yield() { return internal_syscall(SYSCALL(sched_yield)); }
502 
503 void internal_usleep(u64 useconds) {
504   struct timespec ts;
505   ts.tv_sec = useconds / 1000000;
506   ts.tv_nsec = (useconds % 1000000) * 1000;
507   internal_syscall(SYSCALL(nanosleep), &ts, &ts);
508 }
509 
510 uptr internal_execve(const char *filename, char *const argv[],
511                      char *const envp[]) {
512   return internal_syscall(SYSCALL(execve), (uptr)filename, (uptr)argv,
513                           (uptr)envp);
514 }
515 #  endif  // !SANITIZER_SOLARIS && !SANITIZER_NETBSD
516 
517 #  if !SANITIZER_NETBSD
518 void internal__exit(int exitcode) {
519 #    if SANITIZER_FREEBSD || SANITIZER_SOLARIS
520   internal_syscall(SYSCALL(exit), exitcode);
521 #    else
522   internal_syscall(SYSCALL(exit_group), exitcode);
523 #    endif
524   Die();  // Unreachable.
525 }
526 #  endif  // !SANITIZER_NETBSD
527 
528 // ----------------- sanitizer_common.h
529 bool FileExists(const char *filename) {
530   if (ShouldMockFailureToOpen(filename))
531     return false;
532   struct stat st;
533   if (internal_stat(filename, &st))
534     return false;
535   // Sanity check: filename is a regular file.
536   return S_ISREG(st.st_mode);
537 }
538 
539 bool DirExists(const char *path) {
540   struct stat st;
541   if (internal_stat(path, &st))
542     return false;
543   return S_ISDIR(st.st_mode);
544 }
545 
546 #  if !SANITIZER_NETBSD
547 tid_t GetTid() {
548 #    if SANITIZER_FREEBSD
549   long Tid;
550   thr_self(&Tid);
551   return Tid;
552 #    elif SANITIZER_SOLARIS
553   return thr_self();
554 #    else
555   return internal_syscall(SYSCALL(gettid));
556 #    endif
557 }
558 
559 int TgKill(pid_t pid, tid_t tid, int sig) {
560 #    if SANITIZER_LINUX
561   return internal_syscall(SYSCALL(tgkill), pid, tid, sig);
562 #    elif SANITIZER_FREEBSD
563   return internal_syscall(SYSCALL(thr_kill2), pid, tid, sig);
564 #    elif SANITIZER_SOLARIS
565   (void)pid;
566   return thr_kill(tid, sig);
567 #    endif
568 }
569 #  endif
570 
571 #  if SANITIZER_GLIBC
572 u64 NanoTime() {
573   kernel_timeval tv;
574   internal_memset(&tv, 0, sizeof(tv));
575   internal_syscall(SYSCALL(gettimeofday), &tv, 0);
576   return (u64)tv.tv_sec * 1000 * 1000 * 1000 + tv.tv_usec * 1000;
577 }
578 // Used by real_clock_gettime.
579 uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp) {
580   return internal_syscall(SYSCALL(clock_gettime), clk_id, tp);
581 }
582 #  elif !SANITIZER_SOLARIS && !SANITIZER_NETBSD
583 u64 NanoTime() {
584   struct timespec ts;
585   clock_gettime(CLOCK_REALTIME, &ts);
586   return (u64)ts.tv_sec * 1000 * 1000 * 1000 + ts.tv_nsec;
587 }
588 #  endif
589 
590 // Like getenv, but reads env directly from /proc (on Linux) or parses the
591 // 'environ' array (on some others) and does not use libc. This function
592 // should be called first inside __asan_init.
593 const char *GetEnv(const char *name) {
594 #  if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_SOLARIS
595   if (::environ != 0) {
596     uptr NameLen = internal_strlen(name);
597     for (char **Env = ::environ; *Env != 0; Env++) {
598       if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
599         return (*Env) + NameLen + 1;
600     }
601   }
602   return 0;  // Not found.
603 #  elif SANITIZER_LINUX
604   static char *environ;
605   static uptr len;
606   static bool inited;
607   if (!inited) {
608     inited = true;
609     uptr environ_size;
610     if (!ReadFileToBuffer("/proc/self/environ", &environ, &environ_size, &len))
611       environ = nullptr;
612   }
613   if (!environ || len == 0)
614     return nullptr;
615   uptr namelen = internal_strlen(name);
616   const char *p = environ;
617   while (*p != '\0') {  // will happen at the \0\0 that terminates the buffer
618     // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
619     const char *endp = (char *)internal_memchr(p, '\0', len - (p - environ));
620     if (!endp)  // this entry isn't NUL terminated
621       return nullptr;
622     else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=')  // Match.
623       return p + namelen + 1;  // point after =
624     p = endp + 1;
625   }
626   return nullptr;  // Not found.
627 #  else
628 #    error "Unsupported platform"
629 #  endif
630 }
631 
632 #  if !SANITIZER_FREEBSD && !SANITIZER_NETBSD && !SANITIZER_GO
633 extern "C" {
634 SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
635 }
636 #  endif
637 
638 #  if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
639 static void ReadNullSepFileToArray(const char *path, char ***arr,
640                                    int arr_size) {
641   char *buff;
642   uptr buff_size;
643   uptr buff_len;
644   *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
645   if (!ReadFileToBuffer(path, &buff, &buff_size, &buff_len, 1024 * 1024)) {
646     (*arr)[0] = nullptr;
647     return;
648   }
649   (*arr)[0] = buff;
650   int count, i;
651   for (count = 1, i = 1;; i++) {
652     if (buff[i] == 0) {
653       if (buff[i + 1] == 0)
654         break;
655       (*arr)[count] = &buff[i + 1];
656       CHECK_LE(count, arr_size - 1);  // FIXME: make this more flexible.
657       count++;
658     }
659   }
660   (*arr)[count] = nullptr;
661 }
662 #  endif
663 
664 static void GetArgsAndEnv(char ***argv, char ***envp) {
665 #  if SANITIZER_FREEBSD
666   // On FreeBSD, retrieving the argument and environment arrays is done via the
667   // kern.ps_strings sysctl, which returns a pointer to a structure containing
668   // this information. See also <sys/exec.h>.
669   ps_strings *pss;
670   uptr sz = sizeof(pss);
671   if (internal_sysctlbyname("kern.ps_strings", &pss, &sz, NULL, 0) == -1) {
672     Printf("sysctl kern.ps_strings failed\n");
673     Die();
674   }
675   *argv = pss->ps_argvstr;
676   *envp = pss->ps_envstr;
677 #  elif SANITIZER_NETBSD
678   *argv = __ps_strings->ps_argvstr;
679   *envp = __ps_strings->ps_envstr;
680 #  else  // SANITIZER_FREEBSD
681 #    if !SANITIZER_GO
682   if (&__libc_stack_end) {
683     uptr *stack_end = (uptr *)__libc_stack_end;
684     // Normally argc can be obtained from *stack_end, however, on ARM glibc's
685     // _start clobbers it:
686     // https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/arm/start.S;hb=refs/heads/release/2.31/master#l75
687     // Do not special-case ARM and infer argc from argv everywhere.
688     int argc = 0;
689     while (stack_end[argc + 1]) argc++;
690     *argv = (char **)(stack_end + 1);
691     *envp = (char **)(stack_end + argc + 2);
692   } else {
693 #    endif  // !SANITIZER_GO
694     static const int kMaxArgv = 2000, kMaxEnvp = 2000;
695     ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
696     ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
697 #    if !SANITIZER_GO
698   }
699 #    endif  // !SANITIZER_GO
700 #  endif    // SANITIZER_FREEBSD
701 }
702 
703 char **GetArgv() {
704   char **argv, **envp;
705   GetArgsAndEnv(&argv, &envp);
706   return argv;
707 }
708 
709 char **GetEnviron() {
710   char **argv, **envp;
711   GetArgsAndEnv(&argv, &envp);
712   return envp;
713 }
714 
715 #  if !SANITIZER_SOLARIS
716 void FutexWait(atomic_uint32_t *p, u32 cmp) {
717 #    if SANITIZER_FREEBSD
718   _umtx_op(p, UMTX_OP_WAIT_UINT, cmp, 0, 0);
719 #    elif SANITIZER_NETBSD
720   sched_yield(); /* No userspace futex-like synchronization */
721 #    else
722   internal_syscall(SYSCALL(futex), (uptr)p, FUTEX_WAIT_PRIVATE, cmp, 0, 0, 0);
723 #    endif
724 }
725 
726 void FutexWake(atomic_uint32_t *p, u32 count) {
727 #    if SANITIZER_FREEBSD
728   _umtx_op(p, UMTX_OP_WAKE, count, 0, 0);
729 #    elif SANITIZER_NETBSD
730   /* No userspace futex-like synchronization */
731 #    else
732   internal_syscall(SYSCALL(futex), (uptr)p, FUTEX_WAKE_PRIVATE, count, 0, 0, 0);
733 #    endif
734 }
735 
736 #  endif  // !SANITIZER_SOLARIS
737 
738 // ----------------- sanitizer_linux.h
739 // The actual size of this structure is specified by d_reclen.
740 // Note that getdents64 uses a different structure format. We only provide the
741 // 32-bit syscall here.
742 #  if SANITIZER_NETBSD
743 // Not used
744 #  else
745 struct linux_dirent {
746 #    if SANITIZER_X32 || SANITIZER_LINUX
747   u64 d_ino;
748   u64 d_off;
749 #    else
750   unsigned long d_ino;
751   unsigned long d_off;
752 #    endif
753   unsigned short d_reclen;
754 #    if SANITIZER_LINUX
755   unsigned char d_type;
756 #    endif
757   char d_name[256];
758 };
759 #  endif
760 
761 #  if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
762 // Syscall wrappers.
763 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
764   return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
765                           (uptr)data);
766 }
767 
768 uptr internal_waitpid(int pid, int *status, int options) {
769   return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
770                           0 /* rusage */);
771 }
772 
773 uptr internal_getpid() { return internal_syscall(SYSCALL(getpid)); }
774 
775 uptr internal_getppid() { return internal_syscall(SYSCALL(getppid)); }
776 
777 int internal_dlinfo(void *handle, int request, void *p) {
778 #    if SANITIZER_FREEBSD
779   return dlinfo(handle, request, p);
780 #    else
781   UNIMPLEMENTED();
782 #    endif
783 }
784 
785 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
786 #    if SANITIZER_FREEBSD
787   return internal_syscall(SYSCALL(getdirentries), fd, (uptr)dirp, count, NULL);
788 #    elif SANITIZER_LINUX
789   return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
790 #    else
791   return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
792 #    endif
793 }
794 
795 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
796   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
797 }
798 
799 #    if SANITIZER_LINUX
800 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
801   return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
802 }
803 #      if defined(__x86_64__)
804 #        include <asm/unistd_64.h>
805 // Currently internal_arch_prctl() is only needed on x86_64.
806 uptr internal_arch_prctl(int option, uptr arg2) {
807   return internal_syscall(__NR_arch_prctl, option, arg2);
808 }
809 #      endif
810 #    endif
811 
812 uptr internal_sigaltstack(const void *ss, void *oss) {
813   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
814 }
815 
816 int internal_fork() {
817 #    if SANITIZER_LINUX
818 #      if SANITIZER_S390
819   return internal_syscall(SYSCALL(clone), 0, SIGCHLD);
820 #      else
821   return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
822 #      endif
823 #    else
824   return internal_syscall(SYSCALL(fork));
825 #    endif
826 }
827 
828 #    if SANITIZER_FREEBSD
829 int internal_sysctl(const int *name, unsigned int namelen, void *oldp,
830                     uptr *oldlenp, const void *newp, uptr newlen) {
831   return internal_syscall(SYSCALL(__sysctl), name, namelen, oldp,
832                           (size_t *)oldlenp, newp, (size_t)newlen);
833 }
834 
835 int internal_sysctlbyname(const char *sname, void *oldp, uptr *oldlenp,
836                           const void *newp, uptr newlen) {
837   // Note: this function can be called during startup, so we need to avoid
838   // calling any interceptable functions. On FreeBSD >= 1300045 sysctlbyname()
839   // is a real syscall, but for older versions it calls sysctlnametomib()
840   // followed by sysctl(). To avoid calling the intercepted version and
841   // asserting if this happens during startup, call the real sysctlnametomib()
842   // followed by internal_sysctl() if the syscall is not available.
843 #      ifdef SYS___sysctlbyname
844   return internal_syscall(SYSCALL(__sysctlbyname), sname,
845                           internal_strlen(sname), oldp, (size_t *)oldlenp, newp,
846                           (size_t)newlen);
847 #      else
848   static decltype(sysctlnametomib) *real_sysctlnametomib = nullptr;
849   if (!real_sysctlnametomib)
850     real_sysctlnametomib =
851         (decltype(sysctlnametomib) *)dlsym(RTLD_NEXT, "sysctlnametomib");
852   CHECK(real_sysctlnametomib);
853 
854   int oid[CTL_MAXNAME];
855   size_t len = CTL_MAXNAME;
856   if (real_sysctlnametomib(sname, oid, &len) == -1)
857     return (-1);
858   return internal_sysctl(oid, len, oldp, oldlenp, newp, newlen);
859 #      endif
860 }
861 #    endif
862 
863 #    if SANITIZER_LINUX
864 #      define SA_RESTORER 0x04000000
865 // Doesn't set sa_restorer if the caller did not set it, so use with caution
866 //(see below).
867 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
868   __sanitizer_kernel_sigaction_t k_act, k_oldact;
869   internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
870   internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
871   const __sanitizer_sigaction *u_act = (const __sanitizer_sigaction *)act;
872   __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
873   if (u_act) {
874     k_act.handler = u_act->handler;
875     k_act.sigaction = u_act->sigaction;
876     internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
877                     sizeof(__sanitizer_kernel_sigset_t));
878     // Without SA_RESTORER kernel ignores the calls (probably returns EINVAL).
879     k_act.sa_flags = u_act->sa_flags | SA_RESTORER;
880     // FIXME: most often sa_restorer is unset, however the kernel requires it
881     // to point to a valid signal restorer that calls the rt_sigreturn syscall.
882     // If sa_restorer passed to the kernel is NULL, the program may crash upon
883     // signal delivery or fail to unwind the stack in the signal handler.
884     // libc implementation of sigaction() passes its own restorer to
885     // rt_sigaction, so we need to do the same (we'll need to reimplement the
886     // restorers; for x86_64 the restorer address can be obtained from
887     // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
888 #      if !SANITIZER_ANDROID || !SANITIZER_MIPS32
889     k_act.sa_restorer = u_act->sa_restorer;
890 #      endif
891   }
892 
893   uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
894                                  (uptr)(u_act ? &k_act : nullptr),
895                                  (uptr)(u_oldact ? &k_oldact : nullptr),
896                                  (uptr)sizeof(__sanitizer_kernel_sigset_t));
897 
898   if ((result == 0) && u_oldact) {
899     u_oldact->handler = k_oldact.handler;
900     u_oldact->sigaction = k_oldact.sigaction;
901     internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
902                     sizeof(__sanitizer_kernel_sigset_t));
903     u_oldact->sa_flags = k_oldact.sa_flags;
904 #      if !SANITIZER_ANDROID || !SANITIZER_MIPS32
905     u_oldact->sa_restorer = k_oldact.sa_restorer;
906 #      endif
907   }
908   return result;
909 }
910 #    endif  // SANITIZER_LINUX
911 
912 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
913                           __sanitizer_sigset_t *oldset) {
914 #    if SANITIZER_FREEBSD
915   return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
916 #    else
917   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
918   __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
919   return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how, (uptr)k_set,
920                           (uptr)k_oldset, sizeof(__sanitizer_kernel_sigset_t));
921 #    endif
922 }
923 
924 void internal_sigfillset(__sanitizer_sigset_t *set) {
925   internal_memset(set, 0xff, sizeof(*set));
926 }
927 
928 void internal_sigemptyset(__sanitizer_sigset_t *set) {
929   internal_memset(set, 0, sizeof(*set));
930 }
931 
932 #    if SANITIZER_LINUX
933 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
934   signum -= 1;
935   CHECK_GE(signum, 0);
936   CHECK_LT(signum, sizeof(*set) * 8);
937   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
938   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
939   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
940   k_set->sig[idx] &= ~((uptr)1 << bit);
941 }
942 
943 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
944   signum -= 1;
945   CHECK_GE(signum, 0);
946   CHECK_LT(signum, sizeof(*set) * 8);
947   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
948   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
949   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
950   return k_set->sig[idx] & ((uptr)1 << bit);
951 }
952 #    elif SANITIZER_FREEBSD
953 uptr internal_procctl(int type, int id, int cmd, void *data) {
954   return internal_syscall(SYSCALL(procctl), type, id, cmd, data);
955 }
956 
957 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
958   sigset_t *rset = reinterpret_cast<sigset_t *>(set);
959   sigdelset(rset, signum);
960 }
961 
962 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
963   sigset_t *rset = reinterpret_cast<sigset_t *>(set);
964   return sigismember(rset, signum);
965 }
966 #    endif
967 #  endif  // !SANITIZER_SOLARIS
968 
969 #  if !SANITIZER_NETBSD
970 // ThreadLister implementation.
971 ThreadLister::ThreadLister(pid_t pid) : pid_(pid), buffer_(4096) {
972   char task_directory_path[80];
973   internal_snprintf(task_directory_path, sizeof(task_directory_path),
974                     "/proc/%d/task/", pid);
975   descriptor_ = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
976   if (internal_iserror(descriptor_)) {
977     Report("Can't open /proc/%d/task for reading.\n", pid);
978   }
979 }
980 
981 ThreadLister::Result ThreadLister::ListThreads(
982     InternalMmapVector<tid_t> *threads) {
983   if (internal_iserror(descriptor_))
984     return Error;
985   internal_lseek(descriptor_, 0, SEEK_SET);
986   threads->clear();
987 
988   Result result = Ok;
989   for (bool first_read = true;; first_read = false) {
990     // Resize to max capacity if it was downsized by IsAlive.
991     buffer_.resize(buffer_.capacity());
992     CHECK_GE(buffer_.size(), 4096);
993     uptr read = internal_getdents(
994         descriptor_, (struct linux_dirent *)buffer_.data(), buffer_.size());
995     if (!read)
996       return result;
997     if (internal_iserror(read)) {
998       Report("Can't read directory entries from /proc/%d/task.\n", pid_);
999       return Error;
1000     }
1001 
1002     for (uptr begin = (uptr)buffer_.data(), end = begin + read; begin < end;) {
1003       struct linux_dirent *entry = (struct linux_dirent *)begin;
1004       begin += entry->d_reclen;
1005       if (entry->d_ino == 1) {
1006         // Inode 1 is for bad blocks and also can be a reason for early return.
1007         // Should be emitted if kernel tried to output terminating thread.
1008         // See proc_task_readdir implementation in Linux.
1009         result = Incomplete;
1010       }
1011       if (entry->d_ino && *entry->d_name >= '0' && *entry->d_name <= '9')
1012         threads->push_back(internal_atoll(entry->d_name));
1013     }
1014 
1015     // Now we are going to detect short-read or early EOF. In such cases Linux
1016     // can return inconsistent list with missing alive threads.
1017     // Code will just remember that the list can be incomplete but it will
1018     // continue reads to return as much as possible.
1019     if (!first_read) {
1020       // The first one was a short-read by definition.
1021       result = Incomplete;
1022     } else if (read > buffer_.size() - 1024) {
1023       // Read was close to the buffer size. So double the size and assume the
1024       // worst.
1025       buffer_.resize(buffer_.size() * 2);
1026       result = Incomplete;
1027     } else if (!threads->empty() && !IsAlive(threads->back())) {
1028       // Maybe Linux early returned from read on terminated thread (!pid_alive)
1029       // and failed to restore read position.
1030       // See next_tid and proc_task_instantiate in Linux.
1031       result = Incomplete;
1032     }
1033   }
1034 }
1035 
1036 bool ThreadLister::IsAlive(int tid) {
1037   // /proc/%d/task/%d/status uses same call to detect alive threads as
1038   // proc_task_readdir. See task_state implementation in Linux.
1039   char path[80];
1040   internal_snprintf(path, sizeof(path), "/proc/%d/task/%d/status", pid_, tid);
1041   if (!ReadFileToVector(path, &buffer_) || buffer_.empty())
1042     return false;
1043   buffer_.push_back(0);
1044   static const char kPrefix[] = "\nPPid:";
1045   const char *field = internal_strstr(buffer_.data(), kPrefix);
1046   if (!field)
1047     return false;
1048   field += internal_strlen(kPrefix);
1049   return (int)internal_atoll(field) != 0;
1050 }
1051 
1052 ThreadLister::~ThreadLister() {
1053   if (!internal_iserror(descriptor_))
1054     internal_close(descriptor_);
1055 }
1056 #  endif
1057 
1058 #  if SANITIZER_WORDSIZE == 32
1059 // Take care of unusable kernel area in top gigabyte.
1060 static uptr GetKernelAreaSize() {
1061 #    if SANITIZER_LINUX && !SANITIZER_X32
1062   const uptr gbyte = 1UL << 30;
1063 
1064   // Firstly check if there are writable segments
1065   // mapped to top gigabyte (e.g. stack).
1066   MemoryMappingLayout proc_maps(/*cache_enabled*/ true);
1067   if (proc_maps.Error())
1068     return 0;
1069   MemoryMappedSegment segment;
1070   while (proc_maps.Next(&segment)) {
1071     if ((segment.end >= 3 * gbyte) && segment.IsWritable())
1072       return 0;
1073   }
1074 
1075 #      if !SANITIZER_ANDROID
1076   // Even if nothing is mapped, top Gb may still be accessible
1077   // if we are running on 64-bit kernel.
1078   // Uname may report misleading results if personality type
1079   // is modified (e.g. under schroot) so check this as well.
1080   struct utsname uname_info;
1081   int pers = personality(0xffffffffUL);
1082   if (!(pers & PER_MASK) && internal_uname(&uname_info) == 0 &&
1083       internal_strstr(uname_info.machine, "64"))
1084     return 0;
1085 #      endif  // SANITIZER_ANDROID
1086 
1087   // Top gigabyte is reserved for kernel.
1088   return gbyte;
1089 #    else
1090   return 0;
1091 #    endif  // SANITIZER_LINUX && !SANITIZER_X32
1092 }
1093 #  endif  // SANITIZER_WORDSIZE == 32
1094 
1095 uptr GetMaxVirtualAddress() {
1096 #  if SANITIZER_NETBSD && defined(__x86_64__)
1097   return 0x7f7ffffff000ULL;  // (0x00007f8000000000 - PAGE_SIZE)
1098 #  elif SANITIZER_WORDSIZE == 64
1099 #    if defined(__powerpc64__) || defined(__aarch64__) || defined(__loongarch__)
1100   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
1101   // We somehow need to figure out which one we are using now and choose
1102   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
1103   // Note that with 'ulimit -s unlimited' the stack is moved away from the top
1104   // of the address space, so simply checking the stack address is not enough.
1105   // This should (does) work for both PowerPC64 Endian modes.
1106   // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
1107   // loongarch64 also has multiple address space layouts: default is 47-bit.
1108   return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
1109 #    elif SANITIZER_RISCV64
1110   return (1ULL << 38) - 1;
1111 #    elif SANITIZER_MIPS64
1112   return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
1113 #    elif defined(__s390x__)
1114   return (1ULL << 53) - 1;  // 0x001fffffffffffffUL;
1115 #    elif defined(__sparc__)
1116   return ~(uptr)0;
1117 #    else
1118   return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
1119 #    endif
1120 #  else  // SANITIZER_WORDSIZE == 32
1121 #    if defined(__s390__)
1122   return (1ULL << 31) - 1;  // 0x7fffffff;
1123 #    else
1124   return (1ULL << 32) - 1;  // 0xffffffff;
1125 #    endif
1126 #  endif  // SANITIZER_WORDSIZE
1127 }
1128 
1129 uptr GetMaxUserVirtualAddress() {
1130   uptr addr = GetMaxVirtualAddress();
1131 #  if SANITIZER_WORDSIZE == 32 && !defined(__s390__)
1132   if (!common_flags()->full_address_space)
1133     addr -= GetKernelAreaSize();
1134   CHECK_LT(reinterpret_cast<uptr>(&addr), addr);
1135 #  endif
1136   return addr;
1137 }
1138 
1139 #  if !SANITIZER_ANDROID
1140 uptr GetPageSize() {
1141 #    if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__)) && \
1142         defined(EXEC_PAGESIZE)
1143   return EXEC_PAGESIZE;
1144 #    elif SANITIZER_FREEBSD || SANITIZER_NETBSD
1145   // Use sysctl as sysconf can trigger interceptors internally.
1146   int pz = 0;
1147   uptr pzl = sizeof(pz);
1148   int mib[2] = {CTL_HW, HW_PAGESIZE};
1149   int rv = internal_sysctl(mib, 2, &pz, &pzl, nullptr, 0);
1150   CHECK_EQ(rv, 0);
1151   return (uptr)pz;
1152 #    elif SANITIZER_USE_GETAUXVAL
1153   return getauxval(AT_PAGESZ);
1154 #    else
1155   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
1156 #    endif
1157 }
1158 #  endif  // !SANITIZER_ANDROID
1159 
1160 uptr ReadBinaryName(/*out*/ char *buf, uptr buf_len) {
1161 #  if SANITIZER_SOLARIS
1162   const char *default_module_name = getexecname();
1163   CHECK_NE(default_module_name, NULL);
1164   return internal_snprintf(buf, buf_len, "%s", default_module_name);
1165 #  else
1166 #    if SANITIZER_FREEBSD || SANITIZER_NETBSD
1167 #      if SANITIZER_FREEBSD
1168   const int Mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
1169 #      else
1170   const int Mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME};
1171 #      endif
1172   const char *default_module_name = "kern.proc.pathname";
1173   uptr Size = buf_len;
1174   bool IsErr =
1175       (internal_sysctl(Mib, ARRAY_SIZE(Mib), buf, &Size, NULL, 0) != 0);
1176   int readlink_error = IsErr ? errno : 0;
1177   uptr module_name_len = Size;
1178 #    else
1179   const char *default_module_name = "/proc/self/exe";
1180   uptr module_name_len = internal_readlink(default_module_name, buf, buf_len);
1181   int readlink_error;
1182   bool IsErr = internal_iserror(module_name_len, &readlink_error);
1183 #    endif  // SANITIZER_SOLARIS
1184   if (IsErr) {
1185     // We can't read binary name for some reason, assume it's unknown.
1186     Report(
1187         "WARNING: reading executable name failed with errno %d, "
1188         "some stack frames may not be symbolized\n",
1189         readlink_error);
1190     module_name_len =
1191         internal_snprintf(buf, buf_len, "%s", default_module_name);
1192     CHECK_LT(module_name_len, buf_len);
1193   }
1194   return module_name_len;
1195 #  endif
1196 }
1197 
1198 uptr ReadLongProcessName(/*out*/ char *buf, uptr buf_len) {
1199 #  if SANITIZER_LINUX
1200   char *tmpbuf;
1201   uptr tmpsize;
1202   uptr tmplen;
1203   if (ReadFileToBuffer("/proc/self/cmdline", &tmpbuf, &tmpsize, &tmplen,
1204                        1024 * 1024)) {
1205     internal_strncpy(buf, tmpbuf, buf_len);
1206     UnmapOrDie(tmpbuf, tmpsize);
1207     return internal_strlen(buf);
1208   }
1209 #  endif
1210   return ReadBinaryName(buf, buf_len);
1211 }
1212 
1213 // Match full names of the form /path/to/base_name{-,.}*
1214 bool LibraryNameIs(const char *full_name, const char *base_name) {
1215   const char *name = full_name;
1216   // Strip path.
1217   while (*name != '\0') name++;
1218   while (name > full_name && *name != '/') name--;
1219   if (*name == '/')
1220     name++;
1221   uptr base_name_length = internal_strlen(base_name);
1222   if (internal_strncmp(name, base_name, base_name_length))
1223     return false;
1224   return (name[base_name_length] == '-' || name[base_name_length] == '.');
1225 }
1226 
1227 #  if !SANITIZER_ANDROID
1228 // Call cb for each region mapped by map.
1229 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
1230   CHECK_NE(map, nullptr);
1231 #    if !SANITIZER_FREEBSD
1232   typedef ElfW(Phdr) Elf_Phdr;
1233   typedef ElfW(Ehdr) Elf_Ehdr;
1234 #    endif  // !SANITIZER_FREEBSD
1235   char *base = (char *)map->l_addr;
1236   Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
1237   char *phdrs = base + ehdr->e_phoff;
1238   char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
1239 
1240   // Find the segment with the minimum base so we can "relocate" the p_vaddr
1241   // fields.  Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
1242   // objects have a non-zero base.
1243   uptr preferred_base = (uptr)-1;
1244   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1245     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1246     if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
1247       preferred_base = (uptr)phdr->p_vaddr;
1248   }
1249 
1250   // Compute the delta from the real base to get a relocation delta.
1251   sptr delta = (uptr)base - preferred_base;
1252   // Now we can figure out what the loader really mapped.
1253   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1254     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1255     if (phdr->p_type == PT_LOAD) {
1256       uptr seg_start = phdr->p_vaddr + delta;
1257       uptr seg_end = seg_start + phdr->p_memsz;
1258       // None of these values are aligned.  We consider the ragged edges of the
1259       // load command as defined, since they are mapped from the file.
1260       seg_start = RoundDownTo(seg_start, GetPageSizeCached());
1261       seg_end = RoundUpTo(seg_end, GetPageSizeCached());
1262       cb((void *)seg_start, seg_end - seg_start);
1263     }
1264   }
1265 }
1266 #  endif
1267 
1268 #  if SANITIZER_LINUX
1269 #    if defined(__x86_64__)
1270 // We cannot use glibc's clone wrapper, because it messes with the child
1271 // task's TLS. It writes the PID and TID of the child task to its thread
1272 // descriptor, but in our case the child task shares the thread descriptor with
1273 // the parent (because we don't know how to allocate a new thread
1274 // descriptor to keep glibc happy). So the stock version of clone(), when
1275 // used with CLONE_VM, would end up corrupting the parent's thread descriptor.
1276 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1277                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1278   long long res;
1279   if (!fn || !child_stack)
1280     return -EINVAL;
1281   CHECK_EQ(0, (uptr)child_stack % 16);
1282   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1283   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1284   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1285   register void *r8 __asm__("r8") = newtls;
1286   register int *r10 __asm__("r10") = child_tidptr;
1287   __asm__ __volatile__(
1288       /* %rax = syscall(%rax = SYSCALL(clone),
1289        *                %rdi = flags,
1290        *                %rsi = child_stack,
1291        *                %rdx = parent_tidptr,
1292        *                %r8  = new_tls,
1293        *                %r10 = child_tidptr)
1294        */
1295       "syscall\n"
1296 
1297       /* if (%rax != 0)
1298        *   return;
1299        */
1300       "testq  %%rax,%%rax\n"
1301       "jnz    1f\n"
1302 
1303       /* In the child. Terminate unwind chain. */
1304       // XXX: We should also terminate the CFI unwind chain
1305       // here. Unfortunately clang 3.2 doesn't support the
1306       // necessary CFI directives, so we skip that part.
1307       "xorq   %%rbp,%%rbp\n"
1308 
1309       /* Call "fn(arg)". */
1310       "popq   %%rax\n"
1311       "popq   %%rdi\n"
1312       "call   *%%rax\n"
1313 
1314       /* Call _exit(%rax). */
1315       "movq   %%rax,%%rdi\n"
1316       "movq   %2,%%rax\n"
1317       "syscall\n"
1318 
1319       /* Return to parent. */
1320       "1:\n"
1321       : "=a"(res)
1322       : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)), "S"(child_stack), "D"(flags),
1323         "d"(parent_tidptr), "r"(r8), "r"(r10)
1324       : "memory", "r11", "rcx");
1325   return res;
1326 }
1327 #    elif defined(__mips__)
1328 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1329                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1330   long long res;
1331   if (!fn || !child_stack)
1332     return -EINVAL;
1333   CHECK_EQ(0, (uptr)child_stack % 16);
1334   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1335   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1336   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1337   register void *a3 __asm__("$7") = newtls;
1338   register int *a4 __asm__("$8") = child_tidptr;
1339   // We don't have proper CFI directives here because it requires alot of code
1340   // for very marginal benefits.
1341   __asm__ __volatile__(
1342       /* $v0 = syscall($v0 = __NR_clone,
1343        * $a0 = flags,
1344        * $a1 = child_stack,
1345        * $a2 = parent_tidptr,
1346        * $a3 = new_tls,
1347        * $a4 = child_tidptr)
1348        */
1349       ".cprestore 16;\n"
1350       "move $4,%1;\n"
1351       "move $5,%2;\n"
1352       "move $6,%3;\n"
1353       "move $7,%4;\n"
1354   /* Store the fifth argument on stack
1355    * if we are using 32-bit abi.
1356    */
1357 #      if SANITIZER_WORDSIZE == 32
1358       "lw %5,16($29);\n"
1359 #      else
1360       "move $8,%5;\n"
1361 #      endif
1362       "li $2,%6;\n"
1363       "syscall;\n"
1364 
1365       /* if ($v0 != 0)
1366        * return;
1367        */
1368       "bnez $2,1f;\n"
1369 
1370   /* Call "fn(arg)". */
1371 #      if SANITIZER_WORDSIZE == 32
1372 #        ifdef __BIG_ENDIAN__
1373       "lw $25,4($29);\n"
1374       "lw $4,12($29);\n"
1375 #        else
1376       "lw $25,0($29);\n"
1377       "lw $4,8($29);\n"
1378 #        endif
1379 #      else
1380       "ld $25,0($29);\n"
1381       "ld $4,8($29);\n"
1382 #      endif
1383       "jal $25;\n"
1384 
1385       /* Call _exit($v0). */
1386       "move $4,$2;\n"
1387       "li $2,%7;\n"
1388       "syscall;\n"
1389 
1390       /* Return to parent. */
1391       "1:\n"
1392       : "=r"(res)
1393       : "r"(flags), "r"(child_stack), "r"(parent_tidptr), "r"(a3), "r"(a4),
1394         "i"(__NR_clone), "i"(__NR_exit)
1395       : "memory", "$29");
1396   return res;
1397 }
1398 #    elif SANITIZER_RISCV64
1399 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1400                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1401   if (!fn || !child_stack)
1402     return -EINVAL;
1403 
1404   CHECK_EQ(0, (uptr)child_stack % 16);
1405 
1406   register int res __asm__("a0");
1407   register int __flags __asm__("a0") = flags;
1408   register void *__stack __asm__("a1") = child_stack;
1409   register int *__ptid __asm__("a2") = parent_tidptr;
1410   register void *__tls __asm__("a3") = newtls;
1411   register int *__ctid __asm__("a4") = child_tidptr;
1412   register int (*__fn)(void *) __asm__("a5") = fn;
1413   register void *__arg __asm__("a6") = arg;
1414   register int nr_clone __asm__("a7") = __NR_clone;
1415 
1416   __asm__ __volatile__(
1417       "ecall\n"
1418 
1419       /* if (a0 != 0)
1420        *   return a0;
1421        */
1422       "bnez a0, 1f\n"
1423 
1424       // In the child, now. Call "fn(arg)".
1425       "mv a0, a6\n"
1426       "jalr a5\n"
1427 
1428       // Call _exit(a0).
1429       "addi a7, zero, %9\n"
1430       "ecall\n"
1431       "1:\n"
1432 
1433       : "=r"(res)
1434       : "0"(__flags), "r"(__stack), "r"(__ptid), "r"(__tls), "r"(__ctid),
1435         "r"(__fn), "r"(__arg), "r"(nr_clone), "i"(__NR_exit)
1436       : "memory");
1437   return res;
1438 }
1439 #    elif defined(__aarch64__)
1440 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1441                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1442   register long long res __asm__("x0");
1443   if (!fn || !child_stack)
1444     return -EINVAL;
1445   CHECK_EQ(0, (uptr)child_stack % 16);
1446   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1447   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1448   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1449 
1450   register int (*__fn)(void *) __asm__("x0") = fn;
1451   register void *__stack __asm__("x1") = child_stack;
1452   register int __flags __asm__("x2") = flags;
1453   register void *__arg __asm__("x3") = arg;
1454   register int *__ptid __asm__("x4") = parent_tidptr;
1455   register void *__tls __asm__("x5") = newtls;
1456   register int *__ctid __asm__("x6") = child_tidptr;
1457 
1458   __asm__ __volatile__(
1459       "mov x0,x2\n" /* flags  */
1460       "mov x2,x4\n" /* ptid  */
1461       "mov x3,x5\n" /* tls  */
1462       "mov x4,x6\n" /* ctid  */
1463       "mov x8,%9\n" /* clone  */
1464 
1465       "svc 0x0\n"
1466 
1467       /* if (%r0 != 0)
1468        *   return %r0;
1469        */
1470       "cmp x0, #0\n"
1471       "bne 1f\n"
1472 
1473       /* In the child, now. Call "fn(arg)". */
1474       "ldp x1, x0, [sp], #16\n"
1475       "blr x1\n"
1476 
1477       /* Call _exit(%r0).  */
1478       "mov x8, %10\n"
1479       "svc 0x0\n"
1480       "1:\n"
1481 
1482       : "=r"(res)
1483       : "i"(-EINVAL), "r"(__fn), "r"(__stack), "r"(__flags), "r"(__arg),
1484         "r"(__ptid), "r"(__tls), "r"(__ctid), "i"(__NR_clone), "i"(__NR_exit)
1485       : "x30", "memory");
1486   return res;
1487 }
1488 #    elif SANITIZER_LOONGARCH64
1489 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1490                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1491   if (!fn || !child_stack)
1492     return -EINVAL;
1493 
1494   CHECK_EQ(0, (uptr)child_stack % 16);
1495 
1496   register int res __asm__("$a0");
1497   register int __flags __asm__("$a0") = flags;
1498   register void *__stack __asm__("$a1") = child_stack;
1499   register int *__ptid __asm__("$a2") = parent_tidptr;
1500   register int *__ctid __asm__("$a3") = child_tidptr;
1501   register void *__tls __asm__("$a4") = newtls;
1502   register int (*__fn)(void *) __asm__("$a5") = fn;
1503   register void *__arg __asm__("$a6") = arg;
1504   register int nr_clone __asm__("$a7") = __NR_clone;
1505 
1506   __asm__ __volatile__(
1507       "syscall 0\n"
1508 
1509       // if ($a0 != 0)
1510       //   return $a0;
1511       "bnez $a0, 1f\n"
1512 
1513       // In the child, now. Call "fn(arg)".
1514       "move $a0, $a6\n"
1515       "jirl $ra, $a5, 0\n"
1516 
1517       // Call _exit($a0).
1518       "addi.d $a7, $zero, %9\n"
1519       "syscall 0\n"
1520 
1521       "1:\n"
1522 
1523       : "=r"(res)
1524       : "0"(__flags), "r"(__stack), "r"(__ptid), "r"(__ctid), "r"(__tls),
1525         "r"(__fn), "r"(__arg), "r"(nr_clone), "i"(__NR_exit)
1526       : "memory", "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7",
1527         "$t8");
1528   return res;
1529 }
1530 #    elif defined(__powerpc64__)
1531 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1532                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1533   long long res;
1534 // Stack frame structure.
1535 #      if SANITIZER_PPC64V1
1536   //   Back chain == 0        (SP + 112)
1537   // Frame (112 bytes):
1538   //   Parameter save area    (SP + 48), 8 doublewords
1539   //   TOC save area          (SP + 40)
1540   //   Link editor doubleword (SP + 32)
1541   //   Compiler doubleword    (SP + 24)
1542   //   LR save area           (SP + 16)
1543   //   CR save area           (SP + 8)
1544   //   Back chain             (SP + 0)
1545 #        define FRAME_SIZE 112
1546 #        define FRAME_TOC_SAVE_OFFSET 40
1547 #      elif SANITIZER_PPC64V2
1548   //   Back chain == 0        (SP + 32)
1549   // Frame (32 bytes):
1550   //   TOC save area          (SP + 24)
1551   //   LR save area           (SP + 16)
1552   //   CR save area           (SP + 8)
1553   //   Back chain             (SP + 0)
1554 #        define FRAME_SIZE 32
1555 #        define FRAME_TOC_SAVE_OFFSET 24
1556 #      else
1557 #        error "Unsupported PPC64 ABI"
1558 #      endif
1559   if (!fn || !child_stack)
1560     return -EINVAL;
1561   CHECK_EQ(0, (uptr)child_stack % 16);
1562 
1563   register int (*__fn)(void *) __asm__("r3") = fn;
1564   register void *__cstack __asm__("r4") = child_stack;
1565   register int __flags __asm__("r5") = flags;
1566   register void *__arg __asm__("r6") = arg;
1567   register int *__ptidptr __asm__("r7") = parent_tidptr;
1568   register void *__newtls __asm__("r8") = newtls;
1569   register int *__ctidptr __asm__("r9") = child_tidptr;
1570 
1571   __asm__ __volatile__(
1572       /* fn and arg are saved across the syscall */
1573       "mr 28, %5\n\t"
1574       "mr 27, %8\n\t"
1575 
1576       /* syscall
1577         r0 == __NR_clone
1578         r3 == flags
1579         r4 == child_stack
1580         r5 == parent_tidptr
1581         r6 == newtls
1582         r7 == child_tidptr */
1583       "mr 3, %7\n\t"
1584       "mr 5, %9\n\t"
1585       "mr 6, %10\n\t"
1586       "mr 7, %11\n\t"
1587       "li 0, %3\n\t"
1588       "sc\n\t"
1589 
1590       /* Test if syscall was successful */
1591       "cmpdi  cr1, 3, 0\n\t"
1592       "crandc cr1*4+eq, cr1*4+eq, cr0*4+so\n\t"
1593       "bne-   cr1, 1f\n\t"
1594 
1595       /* Set up stack frame */
1596       "li    29, 0\n\t"
1597       "stdu  29, -8(1)\n\t"
1598       "stdu  1, -%12(1)\n\t"
1599       /* Do the function call */
1600       "std   2, %13(1)\n\t"
1601 #      if SANITIZER_PPC64V1
1602       "ld    0, 0(28)\n\t"
1603       "ld    2, 8(28)\n\t"
1604       "mtctr 0\n\t"
1605 #      elif SANITIZER_PPC64V2
1606       "mr    12, 28\n\t"
1607       "mtctr 12\n\t"
1608 #      else
1609 #        error "Unsupported PPC64 ABI"
1610 #      endif
1611       "mr    3, 27\n\t"
1612       "bctrl\n\t"
1613       "ld    2, %13(1)\n\t"
1614 
1615       /* Call _exit(r3) */
1616       "li 0, %4\n\t"
1617       "sc\n\t"
1618 
1619       /* Return to parent */
1620       "1:\n\t"
1621       "mr %0, 3\n\t"
1622       : "=r"(res)
1623       : "0"(-1), "i"(EINVAL), "i"(__NR_clone), "i"(__NR_exit), "r"(__fn),
1624         "r"(__cstack), "r"(__flags), "r"(__arg), "r"(__ptidptr), "r"(__newtls),
1625         "r"(__ctidptr), "i"(FRAME_SIZE), "i"(FRAME_TOC_SAVE_OFFSET)
1626       : "cr0", "cr1", "memory", "ctr", "r0", "r27", "r28", "r29");
1627   return res;
1628 }
1629 #    elif defined(__i386__)
1630 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1631                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1632   int res;
1633   if (!fn || !child_stack)
1634     return -EINVAL;
1635   CHECK_EQ(0, (uptr)child_stack % 16);
1636   child_stack = (char *)child_stack - 7 * sizeof(unsigned int);
1637   ((unsigned int *)child_stack)[0] = (uptr)flags;
1638   ((unsigned int *)child_stack)[1] = (uptr)0;
1639   ((unsigned int *)child_stack)[2] = (uptr)fn;
1640   ((unsigned int *)child_stack)[3] = (uptr)arg;
1641   __asm__ __volatile__(
1642       /* %eax = syscall(%eax = SYSCALL(clone),
1643        *                %ebx = flags,
1644        *                %ecx = child_stack,
1645        *                %edx = parent_tidptr,
1646        *                %esi  = new_tls,
1647        *                %edi = child_tidptr)
1648        */
1649 
1650       /* Obtain flags */
1651       "movl    (%%ecx), %%ebx\n"
1652       /* Do the system call */
1653       "pushl   %%ebx\n"
1654       "pushl   %%esi\n"
1655       "pushl   %%edi\n"
1656       /* Remember the flag value.  */
1657       "movl    %%ebx, (%%ecx)\n"
1658       "int     $0x80\n"
1659       "popl    %%edi\n"
1660       "popl    %%esi\n"
1661       "popl    %%ebx\n"
1662 
1663       /* if (%eax != 0)
1664        *   return;
1665        */
1666 
1667       "test    %%eax,%%eax\n"
1668       "jnz    1f\n"
1669 
1670       /* terminate the stack frame */
1671       "xorl   %%ebp,%%ebp\n"
1672       /* Call FN. */
1673       "call    *%%ebx\n"
1674 #      ifdef PIC
1675       "call    here\n"
1676       "here:\n"
1677       "popl    %%ebx\n"
1678       "addl    $_GLOBAL_OFFSET_TABLE_+[.-here], %%ebx\n"
1679 #      endif
1680       /* Call exit */
1681       "movl    %%eax, %%ebx\n"
1682       "movl    %2, %%eax\n"
1683       "int     $0x80\n"
1684       "1:\n"
1685       : "=a"(res)
1686       : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)), "c"(child_stack),
1687         "d"(parent_tidptr), "S"(newtls), "D"(child_tidptr)
1688       : "memory");
1689   return res;
1690 }
1691 #    elif defined(__arm__)
1692 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1693                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1694   unsigned int res;
1695   if (!fn || !child_stack)
1696     return -EINVAL;
1697   child_stack = (char *)child_stack - 2 * sizeof(unsigned int);
1698   ((unsigned int *)child_stack)[0] = (uptr)fn;
1699   ((unsigned int *)child_stack)[1] = (uptr)arg;
1700   register int r0 __asm__("r0") = flags;
1701   register void *r1 __asm__("r1") = child_stack;
1702   register int *r2 __asm__("r2") = parent_tidptr;
1703   register void *r3 __asm__("r3") = newtls;
1704   register int *r4 __asm__("r4") = child_tidptr;
1705   register int r7 __asm__("r7") = __NR_clone;
1706 
1707 #      if __ARM_ARCH > 4 || defined(__ARM_ARCH_4T__)
1708 #        define ARCH_HAS_BX
1709 #      endif
1710 #      if __ARM_ARCH > 4
1711 #        define ARCH_HAS_BLX
1712 #      endif
1713 
1714 #      ifdef ARCH_HAS_BX
1715 #        ifdef ARCH_HAS_BLX
1716 #          define BLX(R) "blx " #R "\n"
1717 #        else
1718 #          define BLX(R) "mov lr, pc; bx " #R "\n"
1719 #        endif
1720 #      else
1721 #        define BLX(R) "mov lr, pc; mov pc," #R "\n"
1722 #      endif
1723 
1724   __asm__ __volatile__(
1725       /* %r0 = syscall(%r7 = SYSCALL(clone),
1726        *               %r0 = flags,
1727        *               %r1 = child_stack,
1728        *               %r2 = parent_tidptr,
1729        *               %r3  = new_tls,
1730        *               %r4 = child_tidptr)
1731        */
1732 
1733       /* Do the system call */
1734       "swi 0x0\n"
1735 
1736       /* if (%r0 != 0)
1737        *   return %r0;
1738        */
1739       "cmp r0, #0\n"
1740       "bne 1f\n"
1741 
1742       /* In the child, now. Call "fn(arg)". */
1743       "ldr r0, [sp, #4]\n"
1744       "ldr ip, [sp], #8\n" BLX(ip)
1745       /* Call _exit(%r0). */
1746       "mov r7, %7\n"
1747       "swi 0x0\n"
1748       "1:\n"
1749       "mov %0, r0\n"
1750       : "=r"(res)
1751       : "r"(r0), "r"(r1), "r"(r2), "r"(r3), "r"(r4), "r"(r7), "i"(__NR_exit)
1752       : "memory");
1753   return res;
1754 }
1755 #    endif
1756 #  endif  // SANITIZER_LINUX
1757 
1758 #  if SANITIZER_LINUX
1759 int internal_uname(struct utsname *buf) {
1760   return internal_syscall(SYSCALL(uname), buf);
1761 }
1762 #  endif
1763 
1764 #  if SANITIZER_ANDROID
1765 #    if __ANDROID_API__ < 21
1766 extern "C" __attribute__((weak)) int dl_iterate_phdr(
1767     int (*)(struct dl_phdr_info *, size_t, void *), void *);
1768 #    endif
1769 
1770 static int dl_iterate_phdr_test_cb(struct dl_phdr_info *info, size_t size,
1771                                    void *data) {
1772   // Any name starting with "lib" indicates a bug in L where library base names
1773   // are returned instead of paths.
1774   if (info->dlpi_name && info->dlpi_name[0] == 'l' &&
1775       info->dlpi_name[1] == 'i' && info->dlpi_name[2] == 'b') {
1776     *(bool *)data = true;
1777     return 1;
1778   }
1779   return 0;
1780 }
1781 
1782 static atomic_uint32_t android_api_level;
1783 
1784 static AndroidApiLevel AndroidDetectApiLevelStatic() {
1785 #    if __ANDROID_API__ <= 19
1786   return ANDROID_KITKAT;
1787 #    elif __ANDROID_API__ <= 22
1788   return ANDROID_LOLLIPOP_MR1;
1789 #    else
1790   return ANDROID_POST_LOLLIPOP;
1791 #    endif
1792 }
1793 
1794 static AndroidApiLevel AndroidDetectApiLevel() {
1795   if (!&dl_iterate_phdr)
1796     return ANDROID_KITKAT;  // K or lower
1797   bool base_name_seen = false;
1798   dl_iterate_phdr(dl_iterate_phdr_test_cb, &base_name_seen);
1799   if (base_name_seen)
1800     return ANDROID_LOLLIPOP_MR1;  // L MR1
1801   return ANDROID_POST_LOLLIPOP;   // post-L
1802   // Plain L (API level 21) is completely broken wrt ASan and not very
1803   // interesting to detect.
1804 }
1805 
1806 extern "C" __attribute__((weak)) void *_DYNAMIC;
1807 
1808 AndroidApiLevel AndroidGetApiLevel() {
1809   AndroidApiLevel level =
1810       (AndroidApiLevel)atomic_load(&android_api_level, memory_order_relaxed);
1811   if (level)
1812     return level;
1813   level = &_DYNAMIC == nullptr ? AndroidDetectApiLevelStatic()
1814                                : AndroidDetectApiLevel();
1815   atomic_store(&android_api_level, level, memory_order_relaxed);
1816   return level;
1817 }
1818 
1819 #  endif
1820 
1821 static HandleSignalMode GetHandleSignalModeImpl(int signum) {
1822   switch (signum) {
1823     case SIGABRT:
1824       return common_flags()->handle_abort;
1825     case SIGILL:
1826       return common_flags()->handle_sigill;
1827     case SIGTRAP:
1828       return common_flags()->handle_sigtrap;
1829     case SIGFPE:
1830       return common_flags()->handle_sigfpe;
1831     case SIGSEGV:
1832       return common_flags()->handle_segv;
1833     case SIGBUS:
1834       return common_flags()->handle_sigbus;
1835   }
1836   return kHandleSignalNo;
1837 }
1838 
1839 HandleSignalMode GetHandleSignalMode(int signum) {
1840   HandleSignalMode result = GetHandleSignalModeImpl(signum);
1841   if (result == kHandleSignalYes && !common_flags()->allow_user_segv_handler)
1842     return kHandleSignalExclusive;
1843   return result;
1844 }
1845 
1846 #  if !SANITIZER_GO
1847 void *internal_start_thread(void *(*func)(void *arg), void *arg) {
1848   if (&real_pthread_create == 0)
1849     return nullptr;
1850   // Start the thread with signals blocked, otherwise it can steal user signals.
1851   ScopedBlockSignals block(nullptr);
1852   void *th;
1853   real_pthread_create(&th, nullptr, func, arg);
1854   return th;
1855 }
1856 
1857 void internal_join_thread(void *th) {
1858   if (&real_pthread_join)
1859     real_pthread_join(th, nullptr);
1860 }
1861 #  else
1862 void *internal_start_thread(void *(*func)(void *), void *arg) { return 0; }
1863 
1864 void internal_join_thread(void *th) {}
1865 #  endif
1866 
1867 #  if SANITIZER_LINUX && defined(__aarch64__)
1868 // Android headers in the older NDK releases miss this definition.
1869 struct __sanitizer_esr_context {
1870   struct _aarch64_ctx head;
1871   uint64_t esr;
1872 };
1873 
1874 static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
1875   static const u32 kEsrMagic = 0x45535201;
1876   u8 *aux = reinterpret_cast<u8 *>(ucontext->uc_mcontext.__reserved);
1877   while (true) {
1878     _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
1879     if (ctx->size == 0)
1880       break;
1881     if (ctx->magic == kEsrMagic) {
1882       *esr = ((__sanitizer_esr_context *)ctx)->esr;
1883       return true;
1884     }
1885     aux += ctx->size;
1886   }
1887   return false;
1888 }
1889 #  elif SANITIZER_FREEBSD && defined(__aarch64__)
1890 // FreeBSD doesn't provide ESR in the ucontext.
1891 static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) { return false; }
1892 #  endif
1893 
1894 using Context = ucontext_t;
1895 
1896 SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
1897   Context *ucontext = (Context *)context;
1898 #  if defined(__x86_64__) || defined(__i386__)
1899   static const uptr PF_WRITE = 1U << 1;
1900 #    if SANITIZER_FREEBSD
1901   uptr err = ucontext->uc_mcontext.mc_err;
1902 #    elif SANITIZER_NETBSD
1903   uptr err = ucontext->uc_mcontext.__gregs[_REG_ERR];
1904 #    elif SANITIZER_SOLARIS && defined(__i386__)
1905   const int Err = 13;
1906   uptr err = ucontext->uc_mcontext.gregs[Err];
1907 #    else
1908   uptr err = ucontext->uc_mcontext.gregs[REG_ERR];
1909 #    endif  // SANITIZER_FREEBSD
1910   return err & PF_WRITE ? Write : Read;
1911 #  elif defined(__mips__)
1912   uint32_t *exception_source;
1913   uint32_t faulty_instruction;
1914   uint32_t op_code;
1915 
1916   exception_source = (uint32_t *)ucontext->uc_mcontext.pc;
1917   faulty_instruction = (uint32_t)(*exception_source);
1918 
1919   op_code = (faulty_instruction >> 26) & 0x3f;
1920 
1921   // FIXME: Add support for FPU, microMIPS, DSP, MSA memory instructions.
1922   switch (op_code) {
1923     case 0x28:  // sb
1924     case 0x29:  // sh
1925     case 0x2b:  // sw
1926     case 0x3f:  // sd
1927 #    if __mips_isa_rev < 6
1928     case 0x2c:  // sdl
1929     case 0x2d:  // sdr
1930     case 0x2a:  // swl
1931     case 0x2e:  // swr
1932 #    endif
1933       return SignalContext::Write;
1934 
1935     case 0x20:  // lb
1936     case 0x24:  // lbu
1937     case 0x21:  // lh
1938     case 0x25:  // lhu
1939     case 0x23:  // lw
1940     case 0x27:  // lwu
1941     case 0x37:  // ld
1942 #    if __mips_isa_rev < 6
1943     case 0x1a:  // ldl
1944     case 0x1b:  // ldr
1945     case 0x22:  // lwl
1946     case 0x26:  // lwr
1947 #    endif
1948       return SignalContext::Read;
1949 #    if __mips_isa_rev == 6
1950     case 0x3b:  // pcrel
1951       op_code = (faulty_instruction >> 19) & 0x3;
1952       switch (op_code) {
1953         case 0x1:  // lwpc
1954         case 0x2:  // lwupc
1955           return SignalContext::Read;
1956       }
1957 #    endif
1958   }
1959   return SignalContext::Unknown;
1960 #  elif defined(__arm__)
1961   static const uptr FSR_WRITE = 1U << 11;
1962   uptr fsr = ucontext->uc_mcontext.error_code;
1963   return fsr & FSR_WRITE ? Write : Read;
1964 #  elif defined(__aarch64__)
1965   static const u64 ESR_ELx_WNR = 1U << 6;
1966   u64 esr;
1967   if (!Aarch64GetESR(ucontext, &esr))
1968     return Unknown;
1969   return esr & ESR_ELx_WNR ? Write : Read;
1970 #  elif defined(__loongarch__)
1971   u32 flags = ucontext->uc_mcontext.__flags;
1972   if (flags & SC_ADDRERR_RD)
1973     return SignalContext::Read;
1974   if (flags & SC_ADDRERR_WR)
1975     return SignalContext::Write;
1976   return SignalContext::Unknown;
1977 #  elif defined(__sparc__)
1978   // Decode the instruction to determine the access type.
1979   // From OpenSolaris $SRC/uts/sun4/os/trap.c (get_accesstype).
1980 #    if SANITIZER_SOLARIS
1981   uptr pc = ucontext->uc_mcontext.gregs[REG_PC];
1982 #    else
1983   // Historical BSDism here.
1984   struct sigcontext *scontext = (struct sigcontext *)context;
1985 #      if defined(__arch64__)
1986   uptr pc = scontext->sigc_regs.tpc;
1987 #      else
1988   uptr pc = scontext->si_regs.pc;
1989 #      endif
1990 #    endif
1991   u32 instr = *(u32 *)pc;
1992   return (instr >> 21) & 1 ? Write : Read;
1993 #  elif defined(__riscv)
1994 #    if SANITIZER_FREEBSD
1995   unsigned long pc = ucontext->uc_mcontext.mc_gpregs.gp_sepc;
1996 #    else
1997   unsigned long pc = ucontext->uc_mcontext.__gregs[REG_PC];
1998 #    endif
1999   unsigned faulty_instruction = *(uint16_t *)pc;
2000 
2001 #    if defined(__riscv_compressed)
2002   if ((faulty_instruction & 0x3) != 0x3) {  // it's a compressed instruction
2003     // set op_bits to the instruction bits [1, 0, 15, 14, 13]
2004     unsigned op_bits =
2005         ((faulty_instruction & 0x3) << 3) | (faulty_instruction >> 13);
2006     unsigned rd = faulty_instruction & 0xF80;  // bits 7-11, inclusive
2007     switch (op_bits) {
2008       case 0b10'010:  // c.lwsp (rd != x0)
2009 #      if __riscv_xlen == 64
2010       case 0b10'011:  // c.ldsp (rd != x0)
2011 #      endif
2012         return rd ? SignalContext::Read : SignalContext::Unknown;
2013       case 0b00'010:  // c.lw
2014 #      if __riscv_flen >= 32 && __riscv_xlen == 32
2015       case 0b10'011:  // c.flwsp
2016 #      endif
2017 #      if __riscv_flen >= 32 || __riscv_xlen == 64
2018       case 0b00'011:  // c.flw / c.ld
2019 #      endif
2020 #      if __riscv_flen == 64
2021       case 0b00'001:  // c.fld
2022       case 0b10'001:  // c.fldsp
2023 #      endif
2024         return SignalContext::Read;
2025       case 0b00'110:  // c.sw
2026       case 0b10'110:  // c.swsp
2027 #      if __riscv_flen >= 32 || __riscv_xlen == 64
2028       case 0b00'111:  // c.fsw / c.sd
2029       case 0b10'111:  // c.fswsp / c.sdsp
2030 #      endif
2031 #      if __riscv_flen == 64
2032       case 0b00'101:  // c.fsd
2033       case 0b10'101:  // c.fsdsp
2034 #      endif
2035         return SignalContext::Write;
2036       default:
2037         return SignalContext::Unknown;
2038     }
2039   }
2040 #    endif
2041 
2042   unsigned opcode = faulty_instruction & 0x7f;         // lower 7 bits
2043   unsigned funct3 = (faulty_instruction >> 12) & 0x7;  // bits 12-14, inclusive
2044   switch (opcode) {
2045     case 0b0000011:  // loads
2046       switch (funct3) {
2047         case 0b000:  // lb
2048         case 0b001:  // lh
2049         case 0b010:  // lw
2050 #    if __riscv_xlen == 64
2051         case 0b011:  // ld
2052 #    endif
2053         case 0b100:  // lbu
2054         case 0b101:  // lhu
2055           return SignalContext::Read;
2056         default:
2057           return SignalContext::Unknown;
2058       }
2059     case 0b0100011:  // stores
2060       switch (funct3) {
2061         case 0b000:  // sb
2062         case 0b001:  // sh
2063         case 0b010:  // sw
2064 #    if __riscv_xlen == 64
2065         case 0b011:  // sd
2066 #    endif
2067           return SignalContext::Write;
2068         default:
2069           return SignalContext::Unknown;
2070       }
2071 #    if __riscv_flen >= 32
2072     case 0b0000111:  // floating-point loads
2073       switch (funct3) {
2074         case 0b010:  // flw
2075 #      if __riscv_flen == 64
2076         case 0b011:  // fld
2077 #      endif
2078           return SignalContext::Read;
2079         default:
2080           return SignalContext::Unknown;
2081       }
2082     case 0b0100111:  // floating-point stores
2083       switch (funct3) {
2084         case 0b010:  // fsw
2085 #      if __riscv_flen == 64
2086         case 0b011:  // fsd
2087 #      endif
2088           return SignalContext::Write;
2089         default:
2090           return SignalContext::Unknown;
2091       }
2092 #    endif
2093     default:
2094       return SignalContext::Unknown;
2095   }
2096 #  else
2097   (void)ucontext;
2098   return Unknown;  // FIXME: Implement.
2099 #  endif
2100 }
2101 
2102 bool SignalContext::IsTrueFaultingAddress() const {
2103   auto si = static_cast<const siginfo_t *>(siginfo);
2104   // SIGSEGV signals without a true fault address have si_code set to 128.
2105   return si->si_signo == SIGSEGV && si->si_code != 128;
2106 }
2107 
2108 void SignalContext::DumpAllRegisters(void *context) {
2109   // FIXME: Implement this.
2110 }
2111 
2112 static void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
2113 #  if SANITIZER_NETBSD
2114   // This covers all NetBSD architectures
2115   ucontext_t *ucontext = (ucontext_t *)context;
2116   *pc = _UC_MACHINE_PC(ucontext);
2117   *bp = _UC_MACHINE_FP(ucontext);
2118   *sp = _UC_MACHINE_SP(ucontext);
2119 #  elif defined(__arm__)
2120   ucontext_t *ucontext = (ucontext_t *)context;
2121   *pc = ucontext->uc_mcontext.arm_pc;
2122   *bp = ucontext->uc_mcontext.arm_fp;
2123   *sp = ucontext->uc_mcontext.arm_sp;
2124 #  elif defined(__aarch64__)
2125 #    if SANITIZER_FREEBSD
2126   ucontext_t *ucontext = (ucontext_t *)context;
2127   *pc = ucontext->uc_mcontext.mc_gpregs.gp_elr;
2128   *bp = ucontext->uc_mcontext.mc_gpregs.gp_x[29];
2129   *sp = ucontext->uc_mcontext.mc_gpregs.gp_sp;
2130 #    else
2131   ucontext_t *ucontext = (ucontext_t *)context;
2132   *pc = ucontext->uc_mcontext.pc;
2133   *bp = ucontext->uc_mcontext.regs[29];
2134   *sp = ucontext->uc_mcontext.sp;
2135 #    endif
2136 #  elif defined(__hppa__)
2137   ucontext_t *ucontext = (ucontext_t *)context;
2138   *pc = ucontext->uc_mcontext.sc_iaoq[0];
2139   /* GCC uses %r3 whenever a frame pointer is needed.  */
2140   *bp = ucontext->uc_mcontext.sc_gr[3];
2141   *sp = ucontext->uc_mcontext.sc_gr[30];
2142 #  elif defined(__x86_64__)
2143 #    if SANITIZER_FREEBSD
2144   ucontext_t *ucontext = (ucontext_t *)context;
2145   *pc = ucontext->uc_mcontext.mc_rip;
2146   *bp = ucontext->uc_mcontext.mc_rbp;
2147   *sp = ucontext->uc_mcontext.mc_rsp;
2148 #    else
2149   ucontext_t *ucontext = (ucontext_t *)context;
2150   *pc = ucontext->uc_mcontext.gregs[REG_RIP];
2151   *bp = ucontext->uc_mcontext.gregs[REG_RBP];
2152   *sp = ucontext->uc_mcontext.gregs[REG_RSP];
2153 #    endif
2154 #  elif defined(__i386__)
2155 #    if SANITIZER_FREEBSD
2156   ucontext_t *ucontext = (ucontext_t *)context;
2157   *pc = ucontext->uc_mcontext.mc_eip;
2158   *bp = ucontext->uc_mcontext.mc_ebp;
2159   *sp = ucontext->uc_mcontext.mc_esp;
2160 #    else
2161   ucontext_t *ucontext = (ucontext_t *)context;
2162 #      if SANITIZER_SOLARIS
2163   /* Use the numeric values: the symbolic ones are undefined by llvm
2164      include/llvm/Support/Solaris.h.  */
2165 #        ifndef REG_EIP
2166 #          define REG_EIP 14  // REG_PC
2167 #        endif
2168 #        ifndef REG_EBP
2169 #          define REG_EBP 6  // REG_FP
2170 #        endif
2171 #        ifndef REG_UESP
2172 #          define REG_UESP 17  // REG_SP
2173 #        endif
2174 #      endif
2175   *pc = ucontext->uc_mcontext.gregs[REG_EIP];
2176   *bp = ucontext->uc_mcontext.gregs[REG_EBP];
2177   *sp = ucontext->uc_mcontext.gregs[REG_UESP];
2178 #    endif
2179 #  elif defined(__powerpc__) || defined(__powerpc64__)
2180 #    if SANITIZER_FREEBSD
2181   ucontext_t *ucontext = (ucontext_t *)context;
2182   *pc = ucontext->uc_mcontext.mc_srr0;
2183   *sp = ucontext->uc_mcontext.mc_frame[1];
2184   *bp = ucontext->uc_mcontext.mc_frame[31];
2185 #    else
2186   ucontext_t *ucontext = (ucontext_t *)context;
2187   *pc = ucontext->uc_mcontext.regs->nip;
2188   *sp = ucontext->uc_mcontext.regs->gpr[PT_R1];
2189   // The powerpc{,64}-linux ABIs do not specify r31 as the frame
2190   // pointer, but GCC always uses r31 when we need a frame pointer.
2191   *bp = ucontext->uc_mcontext.regs->gpr[PT_R31];
2192 #    endif
2193 #  elif defined(__sparc__)
2194 #    if defined(__arch64__) || defined(__sparcv9)
2195 #      define STACK_BIAS 2047
2196 #    else
2197 #      define STACK_BIAS 0
2198 #    endif
2199 #    if SANITIZER_SOLARIS
2200   ucontext_t *ucontext = (ucontext_t *)context;
2201   *pc = ucontext->uc_mcontext.gregs[REG_PC];
2202   *sp = ucontext->uc_mcontext.gregs[REG_O6] + STACK_BIAS;
2203 #    else
2204   // Historical BSDism here.
2205   struct sigcontext *scontext = (struct sigcontext *)context;
2206 #      if defined(__arch64__)
2207   *pc = scontext->sigc_regs.tpc;
2208   *sp = scontext->sigc_regs.u_regs[14] + STACK_BIAS;
2209 #      else
2210   *pc = scontext->si_regs.pc;
2211   *sp = scontext->si_regs.u_regs[14];
2212 #      endif
2213 #    endif
2214   *bp = (uptr)((uhwptr *)*sp)[14] + STACK_BIAS;
2215 #  elif defined(__mips__)
2216   ucontext_t *ucontext = (ucontext_t *)context;
2217   *pc = ucontext->uc_mcontext.pc;
2218   *bp = ucontext->uc_mcontext.gregs[30];
2219   *sp = ucontext->uc_mcontext.gregs[29];
2220 #  elif defined(__s390__)
2221   ucontext_t *ucontext = (ucontext_t *)context;
2222 #    if defined(__s390x__)
2223   *pc = ucontext->uc_mcontext.psw.addr;
2224 #    else
2225   *pc = ucontext->uc_mcontext.psw.addr & 0x7fffffff;
2226 #    endif
2227   *bp = ucontext->uc_mcontext.gregs[11];
2228   *sp = ucontext->uc_mcontext.gregs[15];
2229 #  elif defined(__riscv)
2230   ucontext_t *ucontext = (ucontext_t *)context;
2231 #    if SANITIZER_FREEBSD
2232   *pc = ucontext->uc_mcontext.mc_gpregs.gp_sepc;
2233   *bp = ucontext->uc_mcontext.mc_gpregs.gp_s[0];
2234   *sp = ucontext->uc_mcontext.mc_gpregs.gp_sp;
2235 #    else
2236   *pc = ucontext->uc_mcontext.__gregs[REG_PC];
2237   *bp = ucontext->uc_mcontext.__gregs[REG_S0];
2238   *sp = ucontext->uc_mcontext.__gregs[REG_SP];
2239 #    endif
2240 #  elif defined(__hexagon__)
2241   ucontext_t *ucontext = (ucontext_t *)context;
2242   *pc = ucontext->uc_mcontext.pc;
2243   *bp = ucontext->uc_mcontext.r30;
2244   *sp = ucontext->uc_mcontext.r29;
2245 #  elif defined(__loongarch__)
2246   ucontext_t *ucontext = (ucontext_t *)context;
2247   *pc = ucontext->uc_mcontext.__pc;
2248   *bp = ucontext->uc_mcontext.__gregs[22];
2249   *sp = ucontext->uc_mcontext.__gregs[3];
2250 #  else
2251 #    error "Unsupported arch"
2252 #  endif
2253 }
2254 
2255 void SignalContext::InitPcSpBp() { GetPcSpBp(context, &pc, &sp, &bp); }
2256 
2257 void InitializePlatformEarly() {
2258   // Do nothing.
2259 }
2260 
2261 void CheckASLR() {
2262 #  if SANITIZER_NETBSD
2263   int mib[3];
2264   int paxflags;
2265   uptr len = sizeof(paxflags);
2266 
2267   mib[0] = CTL_PROC;
2268   mib[1] = internal_getpid();
2269   mib[2] = PROC_PID_PAXFLAGS;
2270 
2271   if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2272     Printf("sysctl failed\n");
2273     Die();
2274   }
2275 
2276   if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_ASLR)) {
2277     Printf(
2278         "This sanitizer is not compatible with enabled ASLR.\n"
2279         "To disable ASLR, please run \"paxctl +a %s\" and try again.\n",
2280         GetArgv()[0]);
2281     Die();
2282   }
2283 #  elif SANITIZER_FREEBSD
2284   int aslr_status;
2285   int r = internal_procctl(P_PID, 0, PROC_ASLR_STATUS, &aslr_status);
2286   if (UNLIKELY(r == -1)) {
2287     // We're making things less 'dramatic' here since
2288     // the cmd is not necessarily guaranteed to be here
2289     // just yet regarding FreeBSD release
2290     return;
2291   }
2292   if ((aslr_status & PROC_ASLR_ACTIVE) != 0) {
2293     VReport(1,
2294             "This sanitizer is not compatible with enabled ASLR "
2295             "and binaries compiled with PIE\n"
2296             "ASLR will be disabled and the program re-executed.\n");
2297     int aslr_ctl = PROC_ASLR_FORCE_DISABLE;
2298     CHECK_NE(internal_procctl(P_PID, 0, PROC_ASLR_CTL, &aslr_ctl), -1);
2299     ReExec();
2300   }
2301 #  elif SANITIZER_PPC64V2
2302   // Disable ASLR for Linux PPC64LE.
2303   int old_personality = personality(0xffffffff);
2304   if (old_personality != -1 && (old_personality & ADDR_NO_RANDOMIZE) == 0) {
2305     VReport(1,
2306             "WARNING: Program is being run with address space layout "
2307             "randomization (ASLR) enabled which prevents the thread and "
2308             "memory sanitizers from working on powerpc64le.\n"
2309             "ASLR will be disabled and the program re-executed.\n");
2310     CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
2311     ReExec();
2312   }
2313 #  else
2314   // Do nothing
2315 #  endif
2316 }
2317 
2318 void CheckMPROTECT() {
2319 #  if SANITIZER_NETBSD
2320   int mib[3];
2321   int paxflags;
2322   uptr len = sizeof(paxflags);
2323 
2324   mib[0] = CTL_PROC;
2325   mib[1] = internal_getpid();
2326   mib[2] = PROC_PID_PAXFLAGS;
2327 
2328   if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2329     Printf("sysctl failed\n");
2330     Die();
2331   }
2332 
2333   if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_MPROTECT)) {
2334     Printf("This sanitizer is not compatible with enabled MPROTECT\n");
2335     Die();
2336   }
2337 #  else
2338   // Do nothing
2339 #  endif
2340 }
2341 
2342 void CheckNoDeepBind(const char *filename, int flag) {
2343 #  ifdef RTLD_DEEPBIND
2344   if (flag & RTLD_DEEPBIND) {
2345     Report(
2346         "You are trying to dlopen a %s shared library with RTLD_DEEPBIND flag"
2347         " which is incompatible with sanitizer runtime "
2348         "(see https://github.com/google/sanitizers/issues/611 for details"
2349         "). If you want to run %s library under sanitizers please remove "
2350         "RTLD_DEEPBIND from dlopen flags.\n",
2351         filename, filename);
2352     Die();
2353   }
2354 #  endif
2355 }
2356 
2357 uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
2358                               uptr *largest_gap_found,
2359                               uptr *max_occupied_addr) {
2360   UNREACHABLE("FindAvailableMemoryRange is not available");
2361   return 0;
2362 }
2363 
2364 bool GetRandom(void *buffer, uptr length, bool blocking) {
2365   if (!buffer || !length || length > 256)
2366     return false;
2367 #  if SANITIZER_USE_GETENTROPY
2368   uptr rnd = getentropy(buffer, length);
2369   int rverrno = 0;
2370   if (internal_iserror(rnd, &rverrno) && rverrno == EFAULT)
2371     return false;
2372   else if (rnd == 0)
2373     return true;
2374 #  endif  // SANITIZER_USE_GETENTROPY
2375 
2376 #  if SANITIZER_USE_GETRANDOM
2377   static atomic_uint8_t skip_getrandom_syscall;
2378   if (!atomic_load_relaxed(&skip_getrandom_syscall)) {
2379     // Up to 256 bytes, getrandom will not be interrupted.
2380     uptr res = internal_syscall(SYSCALL(getrandom), buffer, length,
2381                                 blocking ? 0 : GRND_NONBLOCK);
2382     int rverrno = 0;
2383     if (internal_iserror(res, &rverrno) && rverrno == ENOSYS)
2384       atomic_store_relaxed(&skip_getrandom_syscall, 1);
2385     else if (res == length)
2386       return true;
2387   }
2388 #  endif  // SANITIZER_USE_GETRANDOM
2389   // Up to 256 bytes, a read off /dev/urandom will not be interrupted.
2390   // blocking is moot here, O_NONBLOCK has no effect when opening /dev/urandom.
2391   uptr fd = internal_open("/dev/urandom", O_RDONLY);
2392   if (internal_iserror(fd))
2393     return false;
2394   uptr res = internal_read(fd, buffer, length);
2395   if (internal_iserror(res))
2396     return false;
2397   internal_close(fd);
2398   return true;
2399 }
2400 
2401 }  // namespace __sanitizer
2402 
2403 #endif
2404