xref: /freebsd/contrib/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp (revision 19fae0f66023a97a9b464b3beeeabb2081f575b3)
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 #include <sys/param.h>
62 #if !SANITIZER_SOLARIS
63 #include <sys/ptrace.h>
64 #endif
65 #include <sys/resource.h>
66 #include <sys/stat.h>
67 #include <sys/syscall.h>
68 #include <sys/time.h>
69 #include <sys/types.h>
70 #include <ucontext.h>
71 #include <unistd.h>
72 
73 #if SANITIZER_LINUX
74 #include <sys/utsname.h>
75 #endif
76 
77 #if SANITIZER_LINUX && !SANITIZER_ANDROID
78 #include <sys/personality.h>
79 #endif
80 
81 #if SANITIZER_LINUX && defined(__loongarch__)
82 #  include <sys/sysmacros.h>
83 #endif
84 
85 #if SANITIZER_FREEBSD
86 #include <sys/exec.h>
87 #include <sys/procctl.h>
88 #include <sys/sysctl.h>
89 #include <machine/atomic.h>
90 extern "C" {
91 // <sys/umtx.h> must be included after <errno.h> and <sys/types.h> on
92 // FreeBSD 9.2 and 10.0.
93 #include <sys/umtx.h>
94 }
95 #include <sys/thr.h>
96 #endif  // SANITIZER_FREEBSD
97 
98 #if SANITIZER_NETBSD
99 #include <limits.h>  // For NAME_MAX
100 #include <sys/sysctl.h>
101 #include <sys/exec.h>
102 extern struct ps_strings *__ps_strings;
103 #endif  // SANITIZER_NETBSD
104 
105 #if SANITIZER_SOLARIS
106 #include <stdlib.h>
107 #include <thread.h>
108 #define environ _environ
109 #endif
110 
111 extern char **environ;
112 
113 #if SANITIZER_LINUX
114 // <linux/time.h>
115 struct kernel_timeval {
116   long tv_sec;
117   long tv_usec;
118 };
119 
120 // <linux/futex.h> is broken on some linux distributions.
121 const int FUTEX_WAIT = 0;
122 const int FUTEX_WAKE = 1;
123 const int FUTEX_PRIVATE_FLAG = 128;
124 const int FUTEX_WAIT_PRIVATE = FUTEX_WAIT | FUTEX_PRIVATE_FLAG;
125 const int FUTEX_WAKE_PRIVATE = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
126 #endif  // SANITIZER_LINUX
127 
128 // Are we using 32-bit or 64-bit Linux syscalls?
129 // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
130 // but it still needs to use 64-bit syscalls.
131 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__powerpc64__) || \
132                         SANITIZER_WORDSIZE == 64 ||                      \
133                         (defined(__mips__) && _MIPS_SIM == _ABIN32))
134 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
135 #else
136 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
137 #endif
138 
139 // Note : FreeBSD had implemented both
140 // Linux apis, available from
141 // future 12.x version most likely
142 #if SANITIZER_LINUX && defined(__NR_getrandom)
143 # if !defined(GRND_NONBLOCK)
144 #  define GRND_NONBLOCK 1
145 # endif
146 # define SANITIZER_USE_GETRANDOM 1
147 #else
148 # define SANITIZER_USE_GETRANDOM 0
149 #endif  // SANITIZER_LINUX && defined(__NR_getrandom)
150 
151 #if SANITIZER_FREEBSD && __FreeBSD_version >= 1200000
152 #  define SANITIZER_USE_GETENTROPY 1
153 #else
154 #  define SANITIZER_USE_GETENTROPY 0
155 #endif
156 
157 namespace __sanitizer {
158 
159 void SetSigProcMask(__sanitizer_sigset_t *set, __sanitizer_sigset_t *old) {
160   CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, set, old));
161 }
162 
163 ScopedBlockSignals::ScopedBlockSignals(__sanitizer_sigset_t *copy) {
164   __sanitizer_sigset_t set;
165   internal_sigfillset(&set);
166 #  if SANITIZER_LINUX && !SANITIZER_ANDROID
167   // Glibc uses SIGSETXID signal during setuid call. If this signal is blocked
168   // on any thread, setuid call hangs.
169   // See test/sanitizer_common/TestCases/Linux/setuid.c.
170   internal_sigdelset(&set, 33);
171 #  endif
172 #  if SANITIZER_LINUX
173   // Seccomp-BPF-sandboxed processes rely on SIGSYS to handle trapped syscalls.
174   // If this signal is blocked, such calls cannot be handled and the process may
175   // hang.
176   internal_sigdelset(&set, 31);
177 #  endif
178   SetSigProcMask(&set, &saved_);
179   if (copy)
180     internal_memcpy(copy, &saved_, sizeof(saved_));
181 }
182 
183 ScopedBlockSignals::~ScopedBlockSignals() { SetSigProcMask(&saved_, nullptr); }
184 
185 #  if SANITIZER_LINUX && defined(__x86_64__)
186 #    include "sanitizer_syscall_linux_x86_64.inc"
187 #  elif SANITIZER_LINUX && SANITIZER_RISCV64
188 #    include "sanitizer_syscall_linux_riscv64.inc"
189 #  elif SANITIZER_LINUX && defined(__aarch64__)
190 #    include "sanitizer_syscall_linux_aarch64.inc"
191 #  elif SANITIZER_LINUX && defined(__arm__)
192 #    include "sanitizer_syscall_linux_arm.inc"
193 #  elif SANITIZER_LINUX && defined(__hexagon__)
194 #    include "sanitizer_syscall_linux_hexagon.inc"
195 #  elif SANITIZER_LINUX && SANITIZER_LOONGARCH64
196 #    include "sanitizer_syscall_linux_loongarch64.inc"
197 #  else
198 #    include "sanitizer_syscall_generic.inc"
199 #  endif
200 
201 // --------------- sanitizer_libc.h
202 #if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
203 #if !SANITIZER_S390
204 uptr internal_mmap(void *addr, uptr length, int prot, int flags, int fd,
205                    u64 offset) {
206 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
207   return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
208                           offset);
209 #else
210   // mmap2 specifies file offset in 4096-byte units.
211   CHECK(IsAligned(offset, 4096));
212   return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
213                           offset / 4096);
214 #endif
215 }
216 #endif // !SANITIZER_S390
217 
218 uptr internal_munmap(void *addr, uptr length) {
219   return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
220 }
221 
222 #if SANITIZER_LINUX
223 uptr internal_mremap(void *old_address, uptr old_size, uptr new_size, int flags,
224                      void *new_address) {
225   return internal_syscall(SYSCALL(mremap), (uptr)old_address, old_size,
226                           new_size, flags, (uptr)new_address);
227 }
228 #endif
229 
230 int internal_mprotect(void *addr, uptr length, int prot) {
231   return internal_syscall(SYSCALL(mprotect), (uptr)addr, length, prot);
232 }
233 
234 int internal_madvise(uptr addr, uptr length, int advice) {
235   return internal_syscall(SYSCALL(madvise), addr, length, advice);
236 }
237 
238 uptr internal_close(fd_t fd) {
239   return internal_syscall(SYSCALL(close), fd);
240 }
241 
242 uptr internal_open(const char *filename, int flags) {
243 #    if SANITIZER_LINUX
244   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags);
245 #else
246   return internal_syscall(SYSCALL(open), (uptr)filename, flags);
247 #endif
248 }
249 
250 uptr internal_open(const char *filename, int flags, u32 mode) {
251 #    if SANITIZER_LINUX
252   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags,
253                           mode);
254 #else
255   return internal_syscall(SYSCALL(open), (uptr)filename, flags, mode);
256 #endif
257 }
258 
259 uptr internal_read(fd_t fd, void *buf, uptr count) {
260   sptr res;
261   HANDLE_EINTR(res,
262                (sptr)internal_syscall(SYSCALL(read), fd, (uptr)buf, count));
263   return res;
264 }
265 
266 uptr internal_write(fd_t fd, const void *buf, uptr count) {
267   sptr res;
268   HANDLE_EINTR(res,
269                (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf, count));
270   return res;
271 }
272 
273 uptr internal_ftruncate(fd_t fd, uptr size) {
274   sptr res;
275   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd,
276                (OFF_T)size));
277   return res;
278 }
279 
280 #if (!SANITIZER_LINUX_USES_64BIT_SYSCALLS || SANITIZER_SPARC) && SANITIZER_LINUX
281 static void stat64_to_stat(struct stat64 *in, struct stat *out) {
282   internal_memset(out, 0, sizeof(*out));
283   out->st_dev = in->st_dev;
284   out->st_ino = in->st_ino;
285   out->st_mode = in->st_mode;
286   out->st_nlink = in->st_nlink;
287   out->st_uid = in->st_uid;
288   out->st_gid = in->st_gid;
289   out->st_rdev = in->st_rdev;
290   out->st_size = in->st_size;
291   out->st_blksize = in->st_blksize;
292   out->st_blocks = in->st_blocks;
293   out->st_atime = in->st_atime;
294   out->st_mtime = in->st_mtime;
295   out->st_ctime = in->st_ctime;
296 }
297 #endif
298 
299 #if SANITIZER_LINUX && defined(__loongarch__)
300 static void statx_to_stat(struct statx *in, struct stat *out) {
301   internal_memset(out, 0, sizeof(*out));
302   out->st_dev = makedev(in->stx_dev_major, in->stx_dev_minor);
303   out->st_ino = in->stx_ino;
304   out->st_mode = in->stx_mode;
305   out->st_nlink = in->stx_nlink;
306   out->st_uid = in->stx_uid;
307   out->st_gid = in->stx_gid;
308   out->st_rdev = makedev(in->stx_rdev_major, in->stx_rdev_minor);
309   out->st_size = in->stx_size;
310   out->st_blksize = in->stx_blksize;
311   out->st_blocks = in->stx_blocks;
312   out->st_atime = in->stx_atime.tv_sec;
313   out->st_atim.tv_nsec = in->stx_atime.tv_nsec;
314   out->st_mtime = in->stx_mtime.tv_sec;
315   out->st_mtim.tv_nsec = in->stx_mtime.tv_nsec;
316   out->st_ctime = in->stx_ctime.tv_sec;
317   out->st_ctim.tv_nsec = in->stx_ctime.tv_nsec;
318 }
319 #endif
320 
321 #if SANITIZER_MIPS64
322 // Undefine compatibility macros from <sys/stat.h>
323 // so that they would not clash with the kernel_stat
324 // st_[a|m|c]time fields
325 #if !SANITIZER_GO
326 #undef st_atime
327 #undef st_mtime
328 #undef st_ctime
329 #endif
330 #if defined(SANITIZER_ANDROID)
331 // Bionic sys/stat.h defines additional macros
332 // for compatibility with the old NDKs and
333 // they clash with the kernel_stat structure
334 // st_[a|m|c]time_nsec fields.
335 #undef st_atime_nsec
336 #undef st_mtime_nsec
337 #undef st_ctime_nsec
338 #endif
339 static void kernel_stat_to_stat(struct kernel_stat *in, struct stat *out) {
340   internal_memset(out, 0, sizeof(*out));
341   out->st_dev = in->st_dev;
342   out->st_ino = in->st_ino;
343   out->st_mode = in->st_mode;
344   out->st_nlink = in->st_nlink;
345   out->st_uid = in->st_uid;
346   out->st_gid = in->st_gid;
347   out->st_rdev = in->st_rdev;
348   out->st_size = in->st_size;
349   out->st_blksize = in->st_blksize;
350   out->st_blocks = in->st_blocks;
351 #if defined(__USE_MISC)     || \
352     defined(__USE_XOPEN2K8) || \
353     defined(SANITIZER_ANDROID)
354   out->st_atim.tv_sec = in->st_atime;
355   out->st_atim.tv_nsec = in->st_atime_nsec;
356   out->st_mtim.tv_sec = in->st_mtime;
357   out->st_mtim.tv_nsec = in->st_mtime_nsec;
358   out->st_ctim.tv_sec = in->st_ctime;
359   out->st_ctim.tv_nsec = in->st_ctime_nsec;
360 #else
361   out->st_atime = in->st_atime;
362   out->st_atimensec = in->st_atime_nsec;
363   out->st_mtime = in->st_mtime;
364   out->st_mtimensec = in->st_mtime_nsec;
365   out->st_ctime = in->st_ctime;
366   out->st_atimensec = in->st_ctime_nsec;
367 #endif
368 }
369 #endif
370 
371 uptr internal_stat(const char *path, void *buf) {
372 #  if SANITIZER_FREEBSD
373   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf, 0);
374 #  elif SANITIZER_LINUX
375 #    if defined(__loongarch__)
376   struct statx bufx;
377   int res = internal_syscall(SYSCALL(statx), AT_FDCWD, (uptr)path,
378                              AT_NO_AUTOMOUNT, STATX_BASIC_STATS, (uptr)&bufx);
379   statx_to_stat(&bufx, (struct stat *)buf);
380   return res;
381 #    elif (SANITIZER_WORDSIZE == 64 || SANITIZER_X32 ||    \
382            (defined(__mips__) && _MIPS_SIM == _ABIN32)) && \
383         !SANITIZER_SPARC
384   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
385                           0);
386 #    else
387   struct stat64 buf64;
388   int res = internal_syscall(SYSCALL(fstatat64), AT_FDCWD, (uptr)path,
389                              (uptr)&buf64, 0);
390   stat64_to_stat(&buf64, (struct stat *)buf);
391   return res;
392 #    endif
393 #  else
394   struct stat64 buf64;
395   int res = internal_syscall(SYSCALL(stat64), path, &buf64);
396   stat64_to_stat(&buf64, (struct stat *)buf);
397   return res;
398 #  endif
399 }
400 
401 uptr internal_lstat(const char *path, void *buf) {
402 #  if SANITIZER_FREEBSD
403   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf,
404                           AT_SYMLINK_NOFOLLOW);
405 #  elif SANITIZER_LINUX
406 #    if defined(__loongarch__)
407   struct statx bufx;
408   int res = internal_syscall(SYSCALL(statx), AT_FDCWD, (uptr)path,
409                              AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT,
410                              STATX_BASIC_STATS, (uptr)&bufx);
411   statx_to_stat(&bufx, (struct stat *)buf);
412   return res;
413 #    elif (defined(_LP64) || SANITIZER_X32 ||              \
414            (defined(__mips__) && _MIPS_SIM == _ABIN32)) && \
415         !SANITIZER_SPARC
416   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
417                           AT_SYMLINK_NOFOLLOW);
418 #    else
419   struct stat64 buf64;
420   int res = internal_syscall(SYSCALL(fstatat64), AT_FDCWD, (uptr)path,
421                              (uptr)&buf64, AT_SYMLINK_NOFOLLOW);
422   stat64_to_stat(&buf64, (struct stat *)buf);
423   return res;
424 #    endif
425 #  else
426   struct stat64 buf64;
427   int res = internal_syscall(SYSCALL(lstat64), path, &buf64);
428   stat64_to_stat(&buf64, (struct stat *)buf);
429   return res;
430 #  endif
431 }
432 
433 uptr internal_fstat(fd_t fd, void *buf) {
434 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
435 #if SANITIZER_MIPS64
436   // For mips64, fstat syscall fills buffer in the format of kernel_stat
437   struct kernel_stat kbuf;
438   int res = internal_syscall(SYSCALL(fstat), fd, &kbuf);
439   kernel_stat_to_stat(&kbuf, (struct stat *)buf);
440   return res;
441 #      elif SANITIZER_LINUX && defined(__loongarch__)
442   struct statx bufx;
443   int res = internal_syscall(SYSCALL(statx), fd, "", AT_EMPTY_PATH,
444                              STATX_BASIC_STATS, (uptr)&bufx);
445   statx_to_stat(&bufx, (struct stat *)buf);
446   return res;
447 #      else
448   return internal_syscall(SYSCALL(fstat), fd, (uptr)buf);
449 #      endif
450 #else
451   struct stat64 buf64;
452   int res = internal_syscall(SYSCALL(fstat64), fd, &buf64);
453   stat64_to_stat(&buf64, (struct stat *)buf);
454   return res;
455 #endif
456 }
457 
458 uptr internal_filesize(fd_t fd) {
459   struct stat st;
460   if (internal_fstat(fd, &st))
461     return -1;
462   return (uptr)st.st_size;
463 }
464 
465 uptr internal_dup(int oldfd) {
466   return internal_syscall(SYSCALL(dup), oldfd);
467 }
468 
469 uptr internal_dup2(int oldfd, int newfd) {
470 #    if SANITIZER_LINUX
471   return internal_syscall(SYSCALL(dup3), oldfd, newfd, 0);
472 #else
473   return internal_syscall(SYSCALL(dup2), oldfd, newfd);
474 #endif
475 }
476 
477 uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
478 #    if SANITIZER_LINUX
479   return internal_syscall(SYSCALL(readlinkat), AT_FDCWD, (uptr)path, (uptr)buf,
480                           bufsize);
481 #else
482   return internal_syscall(SYSCALL(readlink), (uptr)path, (uptr)buf, bufsize);
483 #endif
484 }
485 
486 uptr internal_unlink(const char *path) {
487 #    if SANITIZER_LINUX
488   return internal_syscall(SYSCALL(unlinkat), AT_FDCWD, (uptr)path, 0);
489 #else
490   return internal_syscall(SYSCALL(unlink), (uptr)path);
491 #endif
492 }
493 
494 uptr internal_rename(const char *oldpath, const char *newpath) {
495 #  if (defined(__riscv) || defined(__loongarch__)) && defined(__linux__)
496   return internal_syscall(SYSCALL(renameat2), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
497                           (uptr)newpath, 0);
498 #  elif SANITIZER_LINUX
499   return internal_syscall(SYSCALL(renameat), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
500                           (uptr)newpath);
501 #  else
502   return internal_syscall(SYSCALL(rename), (uptr)oldpath, (uptr)newpath);
503 #  endif
504 }
505 
506 uptr internal_sched_yield() {
507   return internal_syscall(SYSCALL(sched_yield));
508 }
509 
510 void internal_usleep(u64 useconds) {
511   struct timespec ts;
512   ts.tv_sec = useconds / 1000000;
513   ts.tv_nsec = (useconds % 1000000) * 1000;
514   internal_syscall(SYSCALL(nanosleep), &ts, &ts);
515 }
516 
517 uptr internal_execve(const char *filename, char *const argv[],
518                      char *const envp[]) {
519   return internal_syscall(SYSCALL(execve), (uptr)filename, (uptr)argv,
520                           (uptr)envp);
521 }
522 #endif  // !SANITIZER_SOLARIS && !SANITIZER_NETBSD
523 
524 #if !SANITIZER_NETBSD
525 void internal__exit(int exitcode) {
526 #if SANITIZER_FREEBSD || SANITIZER_SOLARIS
527   internal_syscall(SYSCALL(exit), exitcode);
528 #else
529   internal_syscall(SYSCALL(exit_group), exitcode);
530 #endif
531   Die();  // Unreachable.
532 }
533 #endif  // !SANITIZER_NETBSD
534 
535 // ----------------- sanitizer_common.h
536 bool FileExists(const char *filename) {
537   if (ShouldMockFailureToOpen(filename))
538     return false;
539   struct stat st;
540   if (internal_stat(filename, &st))
541     return false;
542   // Sanity check: filename is a regular file.
543   return S_ISREG(st.st_mode);
544 }
545 
546 bool DirExists(const char *path) {
547   struct stat st;
548   if (internal_stat(path, &st))
549     return false;
550   return S_ISDIR(st.st_mode);
551 }
552 
553 #  if !SANITIZER_NETBSD
554 tid_t GetTid() {
555 #if SANITIZER_FREEBSD
556   long Tid;
557   thr_self(&Tid);
558   return Tid;
559 #elif SANITIZER_SOLARIS
560   return thr_self();
561 #else
562   return internal_syscall(SYSCALL(gettid));
563 #endif
564 }
565 
566 int TgKill(pid_t pid, tid_t tid, int sig) {
567 #if SANITIZER_LINUX
568   return internal_syscall(SYSCALL(tgkill), pid, tid, sig);
569 #elif SANITIZER_FREEBSD
570   return internal_syscall(SYSCALL(thr_kill2), pid, tid, sig);
571 #elif SANITIZER_SOLARIS
572   (void)pid;
573   return thr_kill(tid, sig);
574 #endif
575 }
576 #endif
577 
578 #if SANITIZER_GLIBC
579 u64 NanoTime() {
580   kernel_timeval tv;
581   internal_memset(&tv, 0, sizeof(tv));
582   internal_syscall(SYSCALL(gettimeofday), &tv, 0);
583   return (u64)tv.tv_sec * 1000 * 1000 * 1000 + tv.tv_usec * 1000;
584 }
585 // Used by real_clock_gettime.
586 uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp) {
587   return internal_syscall(SYSCALL(clock_gettime), clk_id, tp);
588 }
589 #elif !SANITIZER_SOLARIS && !SANITIZER_NETBSD
590 u64 NanoTime() {
591   struct timespec ts;
592   clock_gettime(CLOCK_REALTIME, &ts);
593   return (u64)ts.tv_sec * 1000 * 1000 * 1000 + ts.tv_nsec;
594 }
595 #endif
596 
597 // Like getenv, but reads env directly from /proc (on Linux) or parses the
598 // 'environ' array (on some others) and does not use libc. This function
599 // should be called first inside __asan_init.
600 const char *GetEnv(const char *name) {
601 #if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_SOLARIS
602   if (::environ != 0) {
603     uptr NameLen = internal_strlen(name);
604     for (char **Env = ::environ; *Env != 0; Env++) {
605       if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
606         return (*Env) + NameLen + 1;
607     }
608   }
609   return 0;  // Not found.
610 #elif SANITIZER_LINUX
611   static char *environ;
612   static uptr len;
613   static bool inited;
614   if (!inited) {
615     inited = true;
616     uptr environ_size;
617     if (!ReadFileToBuffer("/proc/self/environ", &environ, &environ_size, &len))
618       environ = nullptr;
619   }
620   if (!environ || len == 0) return nullptr;
621   uptr namelen = internal_strlen(name);
622   const char *p = environ;
623   while (*p != '\0') {  // will happen at the \0\0 that terminates the buffer
624     // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
625     const char* endp =
626         (char*)internal_memchr(p, '\0', len - (p - environ));
627     if (!endp)  // this entry isn't NUL terminated
628       return nullptr;
629     else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=')  // Match.
630       return p + namelen + 1;  // point after =
631     p = endp + 1;
632   }
633   return nullptr;  // Not found.
634 #else
635 #error "Unsupported platform"
636 #endif
637 }
638 
639 #if !SANITIZER_FREEBSD && !SANITIZER_NETBSD && !SANITIZER_GO
640 extern "C" {
641 SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
642 }
643 #endif
644 
645 #if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
646 static void ReadNullSepFileToArray(const char *path, char ***arr,
647                                    int arr_size) {
648   char *buff;
649   uptr buff_size;
650   uptr buff_len;
651   *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
652   if (!ReadFileToBuffer(path, &buff, &buff_size, &buff_len, 1024 * 1024)) {
653     (*arr)[0] = nullptr;
654     return;
655   }
656   (*arr)[0] = buff;
657   int count, i;
658   for (count = 1, i = 1; ; i++) {
659     if (buff[i] == 0) {
660       if (buff[i+1] == 0) break;
661       (*arr)[count] = &buff[i+1];
662       CHECK_LE(count, arr_size - 1);  // FIXME: make this more flexible.
663       count++;
664     }
665   }
666   (*arr)[count] = nullptr;
667 }
668 #endif
669 
670 static void GetArgsAndEnv(char ***argv, char ***envp) {
671 #if SANITIZER_FREEBSD
672   // On FreeBSD, retrieving the argument and environment arrays is done via the
673   // kern.ps_strings sysctl, which returns a pointer to a structure containing
674   // this information. See also <sys/exec.h>.
675   ps_strings *pss;
676   uptr sz = sizeof(pss);
677   if (internal_sysctlbyname("kern.ps_strings", &pss, &sz, NULL, 0) == -1) {
678     Printf("sysctl kern.ps_strings failed\n");
679     Die();
680   }
681   *argv = pss->ps_argvstr;
682   *envp = pss->ps_envstr;
683 #elif SANITIZER_NETBSD
684   *argv = __ps_strings->ps_argvstr;
685   *envp = __ps_strings->ps_envstr;
686 #else // SANITIZER_FREEBSD
687 #if !SANITIZER_GO
688   if (&__libc_stack_end) {
689     uptr* stack_end = (uptr*)__libc_stack_end;
690     // Normally argc can be obtained from *stack_end, however, on ARM glibc's
691     // _start clobbers it:
692     // https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/arm/start.S;hb=refs/heads/release/2.31/master#l75
693     // Do not special-case ARM and infer argc from argv everywhere.
694     int argc = 0;
695     while (stack_end[argc + 1]) argc++;
696     *argv = (char**)(stack_end + 1);
697     *envp = (char**)(stack_end + argc + 2);
698   } else {
699 #endif // !SANITIZER_GO
700     static const int kMaxArgv = 2000, kMaxEnvp = 2000;
701     ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
702     ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
703 #if !SANITIZER_GO
704   }
705 #endif // !SANITIZER_GO
706 #endif // SANITIZER_FREEBSD
707 }
708 
709 char **GetArgv() {
710   char **argv, **envp;
711   GetArgsAndEnv(&argv, &envp);
712   return argv;
713 }
714 
715 char **GetEnviron() {
716   char **argv, **envp;
717   GetArgsAndEnv(&argv, &envp);
718   return envp;
719 }
720 
721 #if !SANITIZER_SOLARIS
722 void FutexWait(atomic_uint32_t *p, u32 cmp) {
723 #    if SANITIZER_FREEBSD
724   _umtx_op(p, UMTX_OP_WAIT_UINT, cmp, 0, 0);
725 #    elif SANITIZER_NETBSD
726   sched_yield();   /* No userspace futex-like synchronization */
727 #    else
728   internal_syscall(SYSCALL(futex), (uptr)p, FUTEX_WAIT_PRIVATE, cmp, 0, 0, 0);
729 #    endif
730 }
731 
732 void FutexWake(atomic_uint32_t *p, u32 count) {
733 #    if SANITIZER_FREEBSD
734   _umtx_op(p, UMTX_OP_WAKE, count, 0, 0);
735 #    elif SANITIZER_NETBSD
736                    /* No userspace futex-like synchronization */
737 #    else
738   internal_syscall(SYSCALL(futex), (uptr)p, FUTEX_WAKE_PRIVATE, count, 0, 0, 0);
739 #    endif
740 }
741 
742 #  endif  // !SANITIZER_SOLARIS
743 
744 // ----------------- sanitizer_linux.h
745 // The actual size of this structure is specified by d_reclen.
746 // Note that getdents64 uses a different structure format. We only provide the
747 // 32-bit syscall here.
748 #if SANITIZER_NETBSD
749 // Not used
750 #else
751 struct linux_dirent {
752 #    if SANITIZER_X32 || SANITIZER_LINUX
753   u64 d_ino;
754   u64 d_off;
755 #    else
756   unsigned long      d_ino;
757   unsigned long      d_off;
758 #    endif
759   unsigned short     d_reclen;
760 #    if SANITIZER_LINUX
761   unsigned char      d_type;
762 #    endif
763   char               d_name[256];
764 };
765 #endif
766 
767 #if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
768 // Syscall wrappers.
769 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
770   return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
771                           (uptr)data);
772 }
773 
774 uptr internal_waitpid(int pid, int *status, int options) {
775   return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
776                           0 /* rusage */);
777 }
778 
779 uptr internal_getpid() {
780   return internal_syscall(SYSCALL(getpid));
781 }
782 
783 uptr internal_getppid() {
784   return internal_syscall(SYSCALL(getppid));
785 }
786 
787 int internal_dlinfo(void *handle, int request, void *p) {
788 #if SANITIZER_FREEBSD
789   return dlinfo(handle, request, p);
790 #else
791   UNIMPLEMENTED();
792 #endif
793 }
794 
795 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
796 #if SANITIZER_FREEBSD
797   return internal_syscall(SYSCALL(getdirentries), fd, (uptr)dirp, count, NULL);
798 #    elif SANITIZER_LINUX
799   return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
800 #    else
801   return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
802 #    endif
803 }
804 
805 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
806   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
807 }
808 
809 #if SANITIZER_LINUX
810 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
811   return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
812 }
813 #      if defined(__x86_64__)
814 #        include <asm/unistd_64.h>
815 // Currently internal_arch_prctl() is only needed on x86_64.
816 uptr internal_arch_prctl(int option, uptr arg2) {
817   return internal_syscall(__NR_arch_prctl, option, arg2);
818 }
819 #      endif
820 #    endif
821 
822 uptr internal_sigaltstack(const void *ss, void *oss) {
823   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
824 }
825 
826 int internal_fork() {
827 #    if SANITIZER_LINUX
828 #      if SANITIZER_S390
829   return internal_syscall(SYSCALL(clone), 0, SIGCHLD);
830 #      else
831   return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
832 #      endif
833 #    else
834   return internal_syscall(SYSCALL(fork));
835 #    endif
836 }
837 
838 #if SANITIZER_FREEBSD
839 int internal_sysctl(const int *name, unsigned int namelen, void *oldp,
840                     uptr *oldlenp, const void *newp, uptr newlen) {
841   return internal_syscall(SYSCALL(__sysctl), name, namelen, oldp,
842                           (size_t *)oldlenp, newp, (size_t)newlen);
843 }
844 
845 int internal_sysctlbyname(const char *sname, void *oldp, uptr *oldlenp,
846                           const void *newp, uptr newlen) {
847   // Note: this function can be called during startup, so we need to avoid
848   // calling any interceptable functions. On FreeBSD >= 1300045 sysctlbyname()
849   // is a real syscall, but for older versions it calls sysctlnametomib()
850   // followed by sysctl(). To avoid calling the intercepted version and
851   // asserting if this happens during startup, call the real sysctlnametomib()
852   // followed by internal_sysctl() if the syscall is not available.
853 #ifdef SYS___sysctlbyname
854   return internal_syscall(SYSCALL(__sysctlbyname), sname,
855                           internal_strlen(sname), oldp, (size_t *)oldlenp, newp,
856                           (size_t)newlen);
857 #else
858   static decltype(sysctlnametomib) *real_sysctlnametomib = nullptr;
859   if (!real_sysctlnametomib)
860     real_sysctlnametomib =
861         (decltype(sysctlnametomib) *)dlsym(RTLD_NEXT, "sysctlnametomib");
862   CHECK(real_sysctlnametomib);
863 
864   int oid[CTL_MAXNAME];
865   size_t len = CTL_MAXNAME;
866   if (real_sysctlnametomib(sname, oid, &len) == -1)
867     return (-1);
868   return internal_sysctl(oid, len, oldp, oldlenp, newp, newlen);
869 #endif
870 }
871 #endif
872 
873 #if SANITIZER_LINUX
874 #define SA_RESTORER 0x04000000
875 // Doesn't set sa_restorer if the caller did not set it, so use with caution
876 //(see below).
877 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
878   __sanitizer_kernel_sigaction_t k_act, k_oldact;
879   internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
880   internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
881   const __sanitizer_sigaction *u_act = (const __sanitizer_sigaction *)act;
882   __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
883   if (u_act) {
884     k_act.handler = u_act->handler;
885     k_act.sigaction = u_act->sigaction;
886     internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
887                     sizeof(__sanitizer_kernel_sigset_t));
888     // Without SA_RESTORER kernel ignores the calls (probably returns EINVAL).
889     k_act.sa_flags = u_act->sa_flags | SA_RESTORER;
890     // FIXME: most often sa_restorer is unset, however the kernel requires it
891     // to point to a valid signal restorer that calls the rt_sigreturn syscall.
892     // If sa_restorer passed to the kernel is NULL, the program may crash upon
893     // signal delivery or fail to unwind the stack in the signal handler.
894     // libc implementation of sigaction() passes its own restorer to
895     // rt_sigaction, so we need to do the same (we'll need to reimplement the
896     // restorers; for x86_64 the restorer address can be obtained from
897     // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
898 #if !SANITIZER_ANDROID || !SANITIZER_MIPS32
899     k_act.sa_restorer = u_act->sa_restorer;
900 #endif
901   }
902 
903   uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
904       (uptr)(u_act ? &k_act : nullptr),
905       (uptr)(u_oldact ? &k_oldact : nullptr),
906       (uptr)sizeof(__sanitizer_kernel_sigset_t));
907 
908   if ((result == 0) && u_oldact) {
909     u_oldact->handler = k_oldact.handler;
910     u_oldact->sigaction = k_oldact.sigaction;
911     internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
912                     sizeof(__sanitizer_kernel_sigset_t));
913     u_oldact->sa_flags = k_oldact.sa_flags;
914 #if !SANITIZER_ANDROID || !SANITIZER_MIPS32
915     u_oldact->sa_restorer = k_oldact.sa_restorer;
916 #endif
917   }
918   return result;
919 }
920 #endif  // SANITIZER_LINUX
921 
922 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
923                           __sanitizer_sigset_t *oldset) {
924 #if SANITIZER_FREEBSD
925   return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
926 #else
927   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
928   __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
929   return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how, (uptr)k_set,
930                           (uptr)k_oldset, sizeof(__sanitizer_kernel_sigset_t));
931 #endif
932 }
933 
934 void internal_sigfillset(__sanitizer_sigset_t *set) {
935   internal_memset(set, 0xff, sizeof(*set));
936 }
937 
938 void internal_sigemptyset(__sanitizer_sigset_t *set) {
939   internal_memset(set, 0, sizeof(*set));
940 }
941 
942 #if SANITIZER_LINUX
943 void internal_sigdelset(__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   k_set->sig[idx] &= ~((uptr)1 << bit);
951 }
952 
953 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
954   signum -= 1;
955   CHECK_GE(signum, 0);
956   CHECK_LT(signum, sizeof(*set) * 8);
957   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
958   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
959   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
960   return k_set->sig[idx] & ((uptr)1 << bit);
961 }
962 #elif SANITIZER_FREEBSD
963 uptr internal_procctl(int type, int id, int cmd, void *data) {
964   return internal_syscall(SYSCALL(procctl), type, id, cmd, data);
965 }
966 
967 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
968   sigset_t *rset = reinterpret_cast<sigset_t *>(set);
969   sigdelset(rset, signum);
970 }
971 
972 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
973   sigset_t *rset = reinterpret_cast<sigset_t *>(set);
974   return sigismember(rset, signum);
975 }
976 #endif
977 #endif // !SANITIZER_SOLARIS
978 
979 #if !SANITIZER_NETBSD
980 // ThreadLister implementation.
981 ThreadLister::ThreadLister(pid_t pid) : pid_(pid), buffer_(4096) {
982   char task_directory_path[80];
983   internal_snprintf(task_directory_path, sizeof(task_directory_path),
984                     "/proc/%d/task/", pid);
985   descriptor_ = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
986   if (internal_iserror(descriptor_)) {
987     Report("Can't open /proc/%d/task for reading.\n", pid);
988   }
989 }
990 
991 ThreadLister::Result ThreadLister::ListThreads(
992     InternalMmapVector<tid_t> *threads) {
993   if (internal_iserror(descriptor_))
994     return Error;
995   internal_lseek(descriptor_, 0, SEEK_SET);
996   threads->clear();
997 
998   Result result = Ok;
999   for (bool first_read = true;; first_read = false) {
1000     // Resize to max capacity if it was downsized by IsAlive.
1001     buffer_.resize(buffer_.capacity());
1002     CHECK_GE(buffer_.size(), 4096);
1003     uptr read = internal_getdents(
1004         descriptor_, (struct linux_dirent *)buffer_.data(), buffer_.size());
1005     if (!read)
1006       return result;
1007     if (internal_iserror(read)) {
1008       Report("Can't read directory entries from /proc/%d/task.\n", pid_);
1009       return Error;
1010     }
1011 
1012     for (uptr begin = (uptr)buffer_.data(), end = begin + read; begin < end;) {
1013       struct linux_dirent *entry = (struct linux_dirent *)begin;
1014       begin += entry->d_reclen;
1015       if (entry->d_ino == 1) {
1016         // Inode 1 is for bad blocks and also can be a reason for early return.
1017         // Should be emitted if kernel tried to output terminating thread.
1018         // See proc_task_readdir implementation in Linux.
1019         result = Incomplete;
1020       }
1021       if (entry->d_ino && *entry->d_name >= '0' && *entry->d_name <= '9')
1022         threads->push_back(internal_atoll(entry->d_name));
1023     }
1024 
1025     // Now we are going to detect short-read or early EOF. In such cases Linux
1026     // can return inconsistent list with missing alive threads.
1027     // Code will just remember that the list can be incomplete but it will
1028     // continue reads to return as much as possible.
1029     if (!first_read) {
1030       // The first one was a short-read by definition.
1031       result = Incomplete;
1032     } else if (read > buffer_.size() - 1024) {
1033       // Read was close to the buffer size. So double the size and assume the
1034       // worst.
1035       buffer_.resize(buffer_.size() * 2);
1036       result = Incomplete;
1037     } else if (!threads->empty() && !IsAlive(threads->back())) {
1038       // Maybe Linux early returned from read on terminated thread (!pid_alive)
1039       // and failed to restore read position.
1040       // See next_tid and proc_task_instantiate in Linux.
1041       result = Incomplete;
1042     }
1043   }
1044 }
1045 
1046 bool ThreadLister::IsAlive(int tid) {
1047   // /proc/%d/task/%d/status uses same call to detect alive threads as
1048   // proc_task_readdir. See task_state implementation in Linux.
1049   char path[80];
1050   internal_snprintf(path, sizeof(path), "/proc/%d/task/%d/status", pid_, tid);
1051   if (!ReadFileToVector(path, &buffer_) || buffer_.empty())
1052     return false;
1053   buffer_.push_back(0);
1054   static const char kPrefix[] = "\nPPid:";
1055   const char *field = internal_strstr(buffer_.data(), kPrefix);
1056   if (!field)
1057     return false;
1058   field += internal_strlen(kPrefix);
1059   return (int)internal_atoll(field) != 0;
1060 }
1061 
1062 ThreadLister::~ThreadLister() {
1063   if (!internal_iserror(descriptor_))
1064     internal_close(descriptor_);
1065 }
1066 #endif
1067 
1068 #if SANITIZER_WORDSIZE == 32
1069 // Take care of unusable kernel area in top gigabyte.
1070 static uptr GetKernelAreaSize() {
1071 #if SANITIZER_LINUX && !SANITIZER_X32
1072   const uptr gbyte = 1UL << 30;
1073 
1074   // Firstly check if there are writable segments
1075   // mapped to top gigabyte (e.g. stack).
1076   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
1077   if (proc_maps.Error())
1078     return 0;
1079   MemoryMappedSegment segment;
1080   while (proc_maps.Next(&segment)) {
1081     if ((segment.end >= 3 * gbyte) && segment.IsWritable()) return 0;
1082   }
1083 
1084 #if !SANITIZER_ANDROID
1085   // Even if nothing is mapped, top Gb may still be accessible
1086   // if we are running on 64-bit kernel.
1087   // Uname may report misleading results if personality type
1088   // is modified (e.g. under schroot) so check this as well.
1089   struct utsname uname_info;
1090   int pers = personality(0xffffffffUL);
1091   if (!(pers & PER_MASK) && internal_uname(&uname_info) == 0 &&
1092       internal_strstr(uname_info.machine, "64"))
1093     return 0;
1094 #endif  // SANITIZER_ANDROID
1095 
1096   // Top gigabyte is reserved for kernel.
1097   return gbyte;
1098 #else
1099   return 0;
1100 #endif  // SANITIZER_LINUX && !SANITIZER_X32
1101 }
1102 #endif  // SANITIZER_WORDSIZE == 32
1103 
1104 uptr GetMaxVirtualAddress() {
1105 #if SANITIZER_NETBSD && defined(__x86_64__)
1106   return 0x7f7ffffff000ULL;  // (0x00007f8000000000 - PAGE_SIZE)
1107 #elif SANITIZER_WORDSIZE == 64
1108 # if defined(__powerpc64__) || defined(__aarch64__) || defined(__loongarch__)
1109   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
1110   // We somehow need to figure out which one we are using now and choose
1111   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
1112   // Note that with 'ulimit -s unlimited' the stack is moved away from the top
1113   // of the address space, so simply checking the stack address is not enough.
1114   // This should (does) work for both PowerPC64 Endian modes.
1115   // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
1116   // loongarch64 also has multiple address space layouts: default is 47-bit.
1117   return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
1118 #elif SANITIZER_RISCV64
1119   return (1ULL << 38) - 1;
1120 # elif SANITIZER_MIPS64
1121   return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
1122 # elif defined(__s390x__)
1123   return (1ULL << 53) - 1;  // 0x001fffffffffffffUL;
1124 #elif defined(__sparc__)
1125   return ~(uptr)0;
1126 # else
1127   return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
1128 # endif
1129 #else  // SANITIZER_WORDSIZE == 32
1130 # if defined(__s390__)
1131   return (1ULL << 31) - 1;  // 0x7fffffff;
1132 # else
1133   return (1ULL << 32) - 1;  // 0xffffffff;
1134 # endif
1135 #endif  // SANITIZER_WORDSIZE
1136 }
1137 
1138 uptr GetMaxUserVirtualAddress() {
1139   uptr addr = GetMaxVirtualAddress();
1140 #if SANITIZER_WORDSIZE == 32 && !defined(__s390__)
1141   if (!common_flags()->full_address_space)
1142     addr -= GetKernelAreaSize();
1143   CHECK_LT(reinterpret_cast<uptr>(&addr), addr);
1144 #endif
1145   return addr;
1146 }
1147 
1148 #if !SANITIZER_ANDROID
1149 uptr GetPageSize() {
1150 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__)) && \
1151     defined(EXEC_PAGESIZE)
1152   return EXEC_PAGESIZE;
1153 #elif SANITIZER_FREEBSD || SANITIZER_NETBSD
1154 // Use sysctl as sysconf can trigger interceptors internally.
1155   int pz = 0;
1156   uptr pzl = sizeof(pz);
1157   int mib[2] = {CTL_HW, HW_PAGESIZE};
1158   int rv = internal_sysctl(mib, 2, &pz, &pzl, nullptr, 0);
1159   CHECK_EQ(rv, 0);
1160   return (uptr)pz;
1161 #elif SANITIZER_USE_GETAUXVAL
1162   return getauxval(AT_PAGESZ);
1163 #else
1164   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
1165 #endif
1166 }
1167 #endif // !SANITIZER_ANDROID
1168 
1169 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
1170 #if SANITIZER_SOLARIS
1171   const char *default_module_name = getexecname();
1172   CHECK_NE(default_module_name, NULL);
1173   return internal_snprintf(buf, buf_len, "%s", default_module_name);
1174 #else
1175 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
1176 #if SANITIZER_FREEBSD
1177   const int Mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
1178 #else
1179   const int Mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME};
1180 #endif
1181   const char *default_module_name = "kern.proc.pathname";
1182   uptr Size = buf_len;
1183   bool IsErr =
1184       (internal_sysctl(Mib, ARRAY_SIZE(Mib), buf, &Size, NULL, 0) != 0);
1185   int readlink_error = IsErr ? errno : 0;
1186   uptr module_name_len = Size;
1187 #else
1188   const char *default_module_name = "/proc/self/exe";
1189   uptr module_name_len = internal_readlink(
1190       default_module_name, buf, buf_len);
1191   int readlink_error;
1192   bool IsErr = internal_iserror(module_name_len, &readlink_error);
1193 #endif  // SANITIZER_SOLARIS
1194   if (IsErr) {
1195     // We can't read binary name for some reason, assume it's unknown.
1196     Report("WARNING: reading executable name failed with errno %d, "
1197            "some stack frames may not be symbolized\n", readlink_error);
1198     module_name_len = internal_snprintf(buf, buf_len, "%s",
1199                                         default_module_name);
1200     CHECK_LT(module_name_len, buf_len);
1201   }
1202   return module_name_len;
1203 #endif
1204 }
1205 
1206 uptr ReadLongProcessName(/*out*/ char *buf, uptr buf_len) {
1207 #if SANITIZER_LINUX
1208   char *tmpbuf;
1209   uptr tmpsize;
1210   uptr tmplen;
1211   if (ReadFileToBuffer("/proc/self/cmdline", &tmpbuf, &tmpsize, &tmplen,
1212                        1024 * 1024)) {
1213     internal_strncpy(buf, tmpbuf, buf_len);
1214     UnmapOrDie(tmpbuf, tmpsize);
1215     return internal_strlen(buf);
1216   }
1217 #endif
1218   return ReadBinaryName(buf, buf_len);
1219 }
1220 
1221 // Match full names of the form /path/to/base_name{-,.}*
1222 bool LibraryNameIs(const char *full_name, const char *base_name) {
1223   const char *name = full_name;
1224   // Strip path.
1225   while (*name != '\0') name++;
1226   while (name > full_name && *name != '/') name--;
1227   if (*name == '/') name++;
1228   uptr base_name_length = internal_strlen(base_name);
1229   if (internal_strncmp(name, base_name, base_name_length)) return false;
1230   return (name[base_name_length] == '-' || name[base_name_length] == '.');
1231 }
1232 
1233 #if !SANITIZER_ANDROID
1234 // Call cb for each region mapped by map.
1235 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
1236   CHECK_NE(map, nullptr);
1237 #if !SANITIZER_FREEBSD
1238   typedef ElfW(Phdr) Elf_Phdr;
1239   typedef ElfW(Ehdr) Elf_Ehdr;
1240 #endif // !SANITIZER_FREEBSD
1241   char *base = (char *)map->l_addr;
1242   Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
1243   char *phdrs = base + ehdr->e_phoff;
1244   char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
1245 
1246   // Find the segment with the minimum base so we can "relocate" the p_vaddr
1247   // fields.  Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
1248   // objects have a non-zero base.
1249   uptr preferred_base = (uptr)-1;
1250   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1251     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1252     if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
1253       preferred_base = (uptr)phdr->p_vaddr;
1254   }
1255 
1256   // Compute the delta from the real base to get a relocation delta.
1257   sptr delta = (uptr)base - preferred_base;
1258   // Now we can figure out what the loader really mapped.
1259   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1260     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1261     if (phdr->p_type == PT_LOAD) {
1262       uptr seg_start = phdr->p_vaddr + delta;
1263       uptr seg_end = seg_start + phdr->p_memsz;
1264       // None of these values are aligned.  We consider the ragged edges of the
1265       // load command as defined, since they are mapped from the file.
1266       seg_start = RoundDownTo(seg_start, GetPageSizeCached());
1267       seg_end = RoundUpTo(seg_end, GetPageSizeCached());
1268       cb((void *)seg_start, seg_end - seg_start);
1269     }
1270   }
1271 }
1272 #endif
1273 
1274 #if SANITIZER_LINUX
1275 #if defined(__x86_64__)
1276 // We cannot use glibc's clone wrapper, because it messes with the child
1277 // task's TLS. It writes the PID and TID of the child task to its thread
1278 // descriptor, but in our case the child task shares the thread descriptor with
1279 // the parent (because we don't know how to allocate a new thread
1280 // descriptor to keep glibc happy). So the stock version of clone(), when
1281 // used with CLONE_VM, would end up corrupting the parent's thread descriptor.
1282 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1283                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1284   long long res;
1285   if (!fn || !child_stack)
1286     return -EINVAL;
1287   CHECK_EQ(0, (uptr)child_stack % 16);
1288   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1289   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1290   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1291   register void *r8 __asm__("r8") = newtls;
1292   register int *r10 __asm__("r10") = child_tidptr;
1293   __asm__ __volatile__(
1294                        /* %rax = syscall(%rax = SYSCALL(clone),
1295                         *                %rdi = flags,
1296                         *                %rsi = child_stack,
1297                         *                %rdx = parent_tidptr,
1298                         *                %r8  = new_tls,
1299                         *                %r10 = child_tidptr)
1300                         */
1301                        "syscall\n"
1302 
1303                        /* if (%rax != 0)
1304                         *   return;
1305                         */
1306                        "testq  %%rax,%%rax\n"
1307                        "jnz    1f\n"
1308 
1309                        /* In the child. Terminate unwind chain. */
1310                        // XXX: We should also terminate the CFI unwind chain
1311                        // here. Unfortunately clang 3.2 doesn't support the
1312                        // necessary CFI directives, so we skip that part.
1313                        "xorq   %%rbp,%%rbp\n"
1314 
1315                        /* Call "fn(arg)". */
1316                        "popq   %%rax\n"
1317                        "popq   %%rdi\n"
1318                        "call   *%%rax\n"
1319 
1320                        /* Call _exit(%rax). */
1321                        "movq   %%rax,%%rdi\n"
1322                        "movq   %2,%%rax\n"
1323                        "syscall\n"
1324 
1325                        /* Return to parent. */
1326                      "1:\n"
1327                        : "=a" (res)
1328                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1329                          "S"(child_stack),
1330                          "D"(flags),
1331                          "d"(parent_tidptr),
1332                          "r"(r8),
1333                          "r"(r10)
1334                        : "memory", "r11", "rcx");
1335   return res;
1336 }
1337 #elif defined(__mips__)
1338 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1339                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1340   long long res;
1341   if (!fn || !child_stack)
1342     return -EINVAL;
1343   CHECK_EQ(0, (uptr)child_stack % 16);
1344   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1345   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1346   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1347   register void *a3 __asm__("$7") = newtls;
1348   register int *a4 __asm__("$8") = child_tidptr;
1349   // We don't have proper CFI directives here because it requires alot of code
1350   // for very marginal benefits.
1351   __asm__ __volatile__(
1352                        /* $v0 = syscall($v0 = __NR_clone,
1353                         * $a0 = flags,
1354                         * $a1 = child_stack,
1355                         * $a2 = parent_tidptr,
1356                         * $a3 = new_tls,
1357                         * $a4 = child_tidptr)
1358                         */
1359                        ".cprestore 16;\n"
1360                        "move $4,%1;\n"
1361                        "move $5,%2;\n"
1362                        "move $6,%3;\n"
1363                        "move $7,%4;\n"
1364                        /* Store the fifth argument on stack
1365                         * if we are using 32-bit abi.
1366                         */
1367 #if SANITIZER_WORDSIZE == 32
1368                        "lw %5,16($29);\n"
1369 #else
1370                        "move $8,%5;\n"
1371 #endif
1372                        "li $2,%6;\n"
1373                        "syscall;\n"
1374 
1375                        /* if ($v0 != 0)
1376                         * return;
1377                         */
1378                        "bnez $2,1f;\n"
1379 
1380                        /* Call "fn(arg)". */
1381 #if SANITIZER_WORDSIZE == 32
1382 #ifdef __BIG_ENDIAN__
1383                        "lw $25,4($29);\n"
1384                        "lw $4,12($29);\n"
1385 #else
1386                        "lw $25,0($29);\n"
1387                        "lw $4,8($29);\n"
1388 #endif
1389 #else
1390                        "ld $25,0($29);\n"
1391                        "ld $4,8($29);\n"
1392 #endif
1393                        "jal $25;\n"
1394 
1395                        /* Call _exit($v0). */
1396                        "move $4,$2;\n"
1397                        "li $2,%7;\n"
1398                        "syscall;\n"
1399 
1400                        /* Return to parent. */
1401                      "1:\n"
1402                        : "=r" (res)
1403                        : "r"(flags),
1404                          "r"(child_stack),
1405                          "r"(parent_tidptr),
1406                          "r"(a3),
1407                          "r"(a4),
1408                          "i"(__NR_clone),
1409                          "i"(__NR_exit)
1410                        : "memory", "$29" );
1411   return res;
1412 }
1413 #elif SANITIZER_RISCV64
1414 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1415                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1416   if (!fn || !child_stack)
1417     return -EINVAL;
1418 
1419   CHECK_EQ(0, (uptr)child_stack % 16);
1420 
1421   register int res __asm__("a0");
1422   register int __flags __asm__("a0") = flags;
1423   register void *__stack __asm__("a1") = child_stack;
1424   register int *__ptid __asm__("a2") = parent_tidptr;
1425   register void *__tls __asm__("a3") = newtls;
1426   register int *__ctid __asm__("a4") = child_tidptr;
1427   register int (*__fn)(void *) __asm__("a5") = fn;
1428   register void *__arg __asm__("a6") = arg;
1429   register int nr_clone __asm__("a7") = __NR_clone;
1430 
1431   __asm__ __volatile__(
1432       "ecall\n"
1433 
1434       /* if (a0 != 0)
1435        *   return a0;
1436        */
1437       "bnez a0, 1f\n"
1438 
1439       // In the child, now. Call "fn(arg)".
1440       "mv a0, a6\n"
1441       "jalr a5\n"
1442 
1443       // Call _exit(a0).
1444       "addi a7, zero, %9\n"
1445       "ecall\n"
1446       "1:\n"
1447 
1448       : "=r"(res)
1449       : "0"(__flags), "r"(__stack), "r"(__ptid), "r"(__tls), "r"(__ctid),
1450         "r"(__fn), "r"(__arg), "r"(nr_clone), "i"(__NR_exit)
1451       : "memory");
1452   return res;
1453 }
1454 #elif defined(__aarch64__)
1455 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1456                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1457   register long long res __asm__("x0");
1458   if (!fn || !child_stack)
1459     return -EINVAL;
1460   CHECK_EQ(0, (uptr)child_stack % 16);
1461   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1462   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1463   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1464 
1465   register int (*__fn)(void *)  __asm__("x0") = fn;
1466   register void *__stack __asm__("x1") = child_stack;
1467   register int   __flags __asm__("x2") = flags;
1468   register void *__arg   __asm__("x3") = arg;
1469   register int  *__ptid  __asm__("x4") = parent_tidptr;
1470   register void *__tls   __asm__("x5") = newtls;
1471   register int  *__ctid  __asm__("x6") = child_tidptr;
1472 
1473   __asm__ __volatile__(
1474                        "mov x0,x2\n" /* flags  */
1475                        "mov x2,x4\n" /* ptid  */
1476                        "mov x3,x5\n" /* tls  */
1477                        "mov x4,x6\n" /* ctid  */
1478                        "mov x8,%9\n" /* clone  */
1479 
1480                        "svc 0x0\n"
1481 
1482                        /* if (%r0 != 0)
1483                         *   return %r0;
1484                         */
1485                        "cmp x0, #0\n"
1486                        "bne 1f\n"
1487 
1488                        /* In the child, now. Call "fn(arg)". */
1489                        "ldp x1, x0, [sp], #16\n"
1490                        "blr x1\n"
1491 
1492                        /* Call _exit(%r0).  */
1493                        "mov x8, %10\n"
1494                        "svc 0x0\n"
1495                      "1:\n"
1496 
1497                        : "=r" (res)
1498                        : "i"(-EINVAL),
1499                          "r"(__fn), "r"(__stack), "r"(__flags), "r"(__arg),
1500                          "r"(__ptid), "r"(__tls), "r"(__ctid),
1501                          "i"(__NR_clone), "i"(__NR_exit)
1502                        : "x30", "memory");
1503   return res;
1504 }
1505 #elif SANITIZER_LOONGARCH64
1506 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1507                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1508   if (!fn || !child_stack)
1509     return -EINVAL;
1510 
1511   CHECK_EQ(0, (uptr)child_stack % 16);
1512 
1513   register int res __asm__("$a0");
1514   register int __flags __asm__("$a0") = flags;
1515   register void *__stack __asm__("$a1") = child_stack;
1516   register int *__ptid __asm__("$a2") = parent_tidptr;
1517   register int *__ctid __asm__("$a3") = child_tidptr;
1518   register void *__tls __asm__("$a4") = newtls;
1519   register int (*__fn)(void *) __asm__("$a5") = fn;
1520   register void *__arg __asm__("$a6") = arg;
1521   register int nr_clone __asm__("$a7") = __NR_clone;
1522 
1523   __asm__ __volatile__(
1524       "syscall 0\n"
1525 
1526       // if ($a0 != 0)
1527       //   return $a0;
1528       "bnez $a0, 1f\n"
1529 
1530       // In the child, now. Call "fn(arg)".
1531       "move $a0, $a6\n"
1532       "jirl $ra, $a5, 0\n"
1533 
1534       // Call _exit($a0).
1535       "addi.d $a7, $zero, %9\n"
1536       "syscall 0\n"
1537 
1538       "1:\n"
1539 
1540       : "=r"(res)
1541       : "0"(__flags), "r"(__stack), "r"(__ptid), "r"(__ctid), "r"(__tls),
1542         "r"(__fn), "r"(__arg), "r"(nr_clone), "i"(__NR_exit)
1543       : "memory", "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$t8");
1544   return res;
1545 }
1546 #elif defined(__powerpc64__)
1547 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1548                    int *parent_tidptr, void *newtls, int *child_tidptr) {
1549   long long res;
1550 // Stack frame structure.
1551 #if SANITIZER_PPC64V1
1552 //   Back chain == 0        (SP + 112)
1553 // Frame (112 bytes):
1554 //   Parameter save area    (SP + 48), 8 doublewords
1555 //   TOC save area          (SP + 40)
1556 //   Link editor doubleword (SP + 32)
1557 //   Compiler doubleword    (SP + 24)
1558 //   LR save area           (SP + 16)
1559 //   CR save area           (SP + 8)
1560 //   Back chain             (SP + 0)
1561 # define FRAME_SIZE 112
1562 # define FRAME_TOC_SAVE_OFFSET 40
1563 #elif SANITIZER_PPC64V2
1564 //   Back chain == 0        (SP + 32)
1565 // Frame (32 bytes):
1566 //   TOC save area          (SP + 24)
1567 //   LR save area           (SP + 16)
1568 //   CR save area           (SP + 8)
1569 //   Back chain             (SP + 0)
1570 # define FRAME_SIZE 32
1571 # define FRAME_TOC_SAVE_OFFSET 24
1572 #else
1573 # error "Unsupported PPC64 ABI"
1574 #endif
1575   if (!fn || !child_stack)
1576     return -EINVAL;
1577   CHECK_EQ(0, (uptr)child_stack % 16);
1578 
1579   register int (*__fn)(void *) __asm__("r3") = fn;
1580   register void *__cstack      __asm__("r4") = child_stack;
1581   register int __flags         __asm__("r5") = flags;
1582   register void *__arg         __asm__("r6") = arg;
1583   register int *__ptidptr      __asm__("r7") = parent_tidptr;
1584   register void *__newtls      __asm__("r8") = newtls;
1585   register int *__ctidptr      __asm__("r9") = child_tidptr;
1586 
1587  __asm__ __volatile__(
1588            /* fn and arg are saved across the syscall */
1589            "mr 28, %5\n\t"
1590            "mr 27, %8\n\t"
1591 
1592            /* syscall
1593              r0 == __NR_clone
1594              r3 == flags
1595              r4 == child_stack
1596              r5 == parent_tidptr
1597              r6 == newtls
1598              r7 == child_tidptr */
1599            "mr 3, %7\n\t"
1600            "mr 5, %9\n\t"
1601            "mr 6, %10\n\t"
1602            "mr 7, %11\n\t"
1603            "li 0, %3\n\t"
1604            "sc\n\t"
1605 
1606            /* Test if syscall was successful */
1607            "cmpdi  cr1, 3, 0\n\t"
1608            "crandc cr1*4+eq, cr1*4+eq, cr0*4+so\n\t"
1609            "bne-   cr1, 1f\n\t"
1610 
1611            /* Set up stack frame */
1612            "li    29, 0\n\t"
1613            "stdu  29, -8(1)\n\t"
1614            "stdu  1, -%12(1)\n\t"
1615            /* Do the function call */
1616            "std   2, %13(1)\n\t"
1617 #if SANITIZER_PPC64V1
1618            "ld    0, 0(28)\n\t"
1619            "ld    2, 8(28)\n\t"
1620            "mtctr 0\n\t"
1621 #elif SANITIZER_PPC64V2
1622            "mr    12, 28\n\t"
1623            "mtctr 12\n\t"
1624 #else
1625 # error "Unsupported PPC64 ABI"
1626 #endif
1627            "mr    3, 27\n\t"
1628            "bctrl\n\t"
1629            "ld    2, %13(1)\n\t"
1630 
1631            /* Call _exit(r3) */
1632            "li 0, %4\n\t"
1633            "sc\n\t"
1634 
1635            /* Return to parent */
1636            "1:\n\t"
1637            "mr %0, 3\n\t"
1638              : "=r" (res)
1639              : "0" (-1),
1640                "i" (EINVAL),
1641                "i" (__NR_clone),
1642                "i" (__NR_exit),
1643                "r" (__fn),
1644                "r" (__cstack),
1645                "r" (__flags),
1646                "r" (__arg),
1647                "r" (__ptidptr),
1648                "r" (__newtls),
1649                "r" (__ctidptr),
1650                "i" (FRAME_SIZE),
1651                "i" (FRAME_TOC_SAVE_OFFSET)
1652              : "cr0", "cr1", "memory", "ctr", "r0", "r27", "r28", "r29");
1653   return res;
1654 }
1655 #elif defined(__i386__)
1656 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1657                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1658   int res;
1659   if (!fn || !child_stack)
1660     return -EINVAL;
1661   CHECK_EQ(0, (uptr)child_stack % 16);
1662   child_stack = (char *)child_stack - 7 * sizeof(unsigned int);
1663   ((unsigned int *)child_stack)[0] = (uptr)flags;
1664   ((unsigned int *)child_stack)[1] = (uptr)0;
1665   ((unsigned int *)child_stack)[2] = (uptr)fn;
1666   ((unsigned int *)child_stack)[3] = (uptr)arg;
1667   __asm__ __volatile__(
1668                        /* %eax = syscall(%eax = SYSCALL(clone),
1669                         *                %ebx = flags,
1670                         *                %ecx = child_stack,
1671                         *                %edx = parent_tidptr,
1672                         *                %esi  = new_tls,
1673                         *                %edi = child_tidptr)
1674                         */
1675 
1676                         /* Obtain flags */
1677                         "movl    (%%ecx), %%ebx\n"
1678                         /* Do the system call */
1679                         "pushl   %%ebx\n"
1680                         "pushl   %%esi\n"
1681                         "pushl   %%edi\n"
1682                         /* Remember the flag value.  */
1683                         "movl    %%ebx, (%%ecx)\n"
1684                         "int     $0x80\n"
1685                         "popl    %%edi\n"
1686                         "popl    %%esi\n"
1687                         "popl    %%ebx\n"
1688 
1689                         /* if (%eax != 0)
1690                          *   return;
1691                          */
1692 
1693                         "test    %%eax,%%eax\n"
1694                         "jnz    1f\n"
1695 
1696                         /* terminate the stack frame */
1697                         "xorl   %%ebp,%%ebp\n"
1698                         /* Call FN. */
1699                         "call    *%%ebx\n"
1700 #ifdef PIC
1701                         "call    here\n"
1702                         "here:\n"
1703                         "popl    %%ebx\n"
1704                         "addl    $_GLOBAL_OFFSET_TABLE_+[.-here], %%ebx\n"
1705 #endif
1706                         /* Call exit */
1707                         "movl    %%eax, %%ebx\n"
1708                         "movl    %2, %%eax\n"
1709                         "int     $0x80\n"
1710                         "1:\n"
1711                        : "=a" (res)
1712                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1713                          "c"(child_stack),
1714                          "d"(parent_tidptr),
1715                          "S"(newtls),
1716                          "D"(child_tidptr)
1717                        : "memory");
1718   return res;
1719 }
1720 #elif defined(__arm__)
1721 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1722                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1723   unsigned int res;
1724   if (!fn || !child_stack)
1725     return -EINVAL;
1726   child_stack = (char *)child_stack - 2 * sizeof(unsigned int);
1727   ((unsigned int *)child_stack)[0] = (uptr)fn;
1728   ((unsigned int *)child_stack)[1] = (uptr)arg;
1729   register int r0 __asm__("r0") = flags;
1730   register void *r1 __asm__("r1") = child_stack;
1731   register int *r2 __asm__("r2") = parent_tidptr;
1732   register void *r3 __asm__("r3") = newtls;
1733   register int *r4 __asm__("r4") = child_tidptr;
1734   register int r7 __asm__("r7") = __NR_clone;
1735 
1736 #if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
1737 # define ARCH_HAS_BX
1738 #endif
1739 #if __ARM_ARCH > 4
1740 # define ARCH_HAS_BLX
1741 #endif
1742 
1743 #ifdef ARCH_HAS_BX
1744 # ifdef ARCH_HAS_BLX
1745 #  define BLX(R) "blx "  #R "\n"
1746 # else
1747 #  define BLX(R) "mov lr, pc; bx " #R "\n"
1748 # endif
1749 #else
1750 # define BLX(R)  "mov lr, pc; mov pc," #R "\n"
1751 #endif
1752 
1753   __asm__ __volatile__(
1754                        /* %r0 = syscall(%r7 = SYSCALL(clone),
1755                         *               %r0 = flags,
1756                         *               %r1 = child_stack,
1757                         *               %r2 = parent_tidptr,
1758                         *               %r3  = new_tls,
1759                         *               %r4 = child_tidptr)
1760                         */
1761 
1762                        /* Do the system call */
1763                        "swi 0x0\n"
1764 
1765                        /* if (%r0 != 0)
1766                         *   return %r0;
1767                         */
1768                        "cmp r0, #0\n"
1769                        "bne 1f\n"
1770 
1771                        /* In the child, now. Call "fn(arg)". */
1772                        "ldr r0, [sp, #4]\n"
1773                        "ldr ip, [sp], #8\n"
1774                        BLX(ip)
1775                        /* Call _exit(%r0). */
1776                        "mov r7, %7\n"
1777                        "swi 0x0\n"
1778                        "1:\n"
1779                        "mov %0, r0\n"
1780                        : "=r"(res)
1781                        : "r"(r0), "r"(r1), "r"(r2), "r"(r3), "r"(r4), "r"(r7),
1782                          "i"(__NR_exit)
1783                        : "memory");
1784   return res;
1785 }
1786 #endif
1787 #endif  // SANITIZER_LINUX
1788 
1789 #if SANITIZER_LINUX
1790 int internal_uname(struct utsname *buf) {
1791   return internal_syscall(SYSCALL(uname), buf);
1792 }
1793 #endif
1794 
1795 #if SANITIZER_ANDROID
1796 #if __ANDROID_API__ < 21
1797 extern "C" __attribute__((weak)) int dl_iterate_phdr(
1798     int (*)(struct dl_phdr_info *, size_t, void *), void *);
1799 #endif
1800 
1801 static int dl_iterate_phdr_test_cb(struct dl_phdr_info *info, size_t size,
1802                                    void *data) {
1803   // Any name starting with "lib" indicates a bug in L where library base names
1804   // are returned instead of paths.
1805   if (info->dlpi_name && info->dlpi_name[0] == 'l' &&
1806       info->dlpi_name[1] == 'i' && info->dlpi_name[2] == 'b') {
1807     *(bool *)data = true;
1808     return 1;
1809   }
1810   return 0;
1811 }
1812 
1813 static atomic_uint32_t android_api_level;
1814 
1815 static AndroidApiLevel AndroidDetectApiLevelStatic() {
1816 #if __ANDROID_API__ <= 19
1817   return ANDROID_KITKAT;
1818 #elif __ANDROID_API__ <= 22
1819   return ANDROID_LOLLIPOP_MR1;
1820 #else
1821   return ANDROID_POST_LOLLIPOP;
1822 #endif
1823 }
1824 
1825 static AndroidApiLevel AndroidDetectApiLevel() {
1826   if (!&dl_iterate_phdr)
1827     return ANDROID_KITKAT; // K or lower
1828   bool base_name_seen = false;
1829   dl_iterate_phdr(dl_iterate_phdr_test_cb, &base_name_seen);
1830   if (base_name_seen)
1831     return ANDROID_LOLLIPOP_MR1; // L MR1
1832   return ANDROID_POST_LOLLIPOP;   // post-L
1833   // Plain L (API level 21) is completely broken wrt ASan and not very
1834   // interesting to detect.
1835 }
1836 
1837 extern "C" __attribute__((weak)) void* _DYNAMIC;
1838 
1839 AndroidApiLevel AndroidGetApiLevel() {
1840   AndroidApiLevel level =
1841       (AndroidApiLevel)atomic_load(&android_api_level, memory_order_relaxed);
1842   if (level) return level;
1843   level = &_DYNAMIC == nullptr ? AndroidDetectApiLevelStatic()
1844                                : AndroidDetectApiLevel();
1845   atomic_store(&android_api_level, level, memory_order_relaxed);
1846   return level;
1847 }
1848 
1849 #endif
1850 
1851 static HandleSignalMode GetHandleSignalModeImpl(int signum) {
1852   switch (signum) {
1853     case SIGABRT:
1854       return common_flags()->handle_abort;
1855     case SIGILL:
1856       return common_flags()->handle_sigill;
1857     case SIGTRAP:
1858       return common_flags()->handle_sigtrap;
1859     case SIGFPE:
1860       return common_flags()->handle_sigfpe;
1861     case SIGSEGV:
1862       return common_flags()->handle_segv;
1863     case SIGBUS:
1864       return common_flags()->handle_sigbus;
1865   }
1866   return kHandleSignalNo;
1867 }
1868 
1869 HandleSignalMode GetHandleSignalMode(int signum) {
1870   HandleSignalMode result = GetHandleSignalModeImpl(signum);
1871   if (result == kHandleSignalYes && !common_flags()->allow_user_segv_handler)
1872     return kHandleSignalExclusive;
1873   return result;
1874 }
1875 
1876 #if !SANITIZER_GO
1877 void *internal_start_thread(void *(*func)(void *arg), void *arg) {
1878   if (&real_pthread_create == 0)
1879     return nullptr;
1880   // Start the thread with signals blocked, otherwise it can steal user signals.
1881   ScopedBlockSignals block(nullptr);
1882   void *th;
1883   real_pthread_create(&th, nullptr, func, arg);
1884   return th;
1885 }
1886 
1887 void internal_join_thread(void *th) {
1888   if (&real_pthread_join)
1889     real_pthread_join(th, nullptr);
1890 }
1891 #else
1892 void *internal_start_thread(void *(*func)(void *), void *arg) { return 0; }
1893 
1894 void internal_join_thread(void *th) {}
1895 #endif
1896 
1897 #if SANITIZER_LINUX && defined(__aarch64__)
1898 // Android headers in the older NDK releases miss this definition.
1899 struct __sanitizer_esr_context {
1900   struct _aarch64_ctx head;
1901   uint64_t esr;
1902 };
1903 
1904 static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
1905   static const u32 kEsrMagic = 0x45535201;
1906   u8 *aux = reinterpret_cast<u8 *>(ucontext->uc_mcontext.__reserved);
1907   while (true) {
1908     _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
1909     if (ctx->size == 0) break;
1910     if (ctx->magic == kEsrMagic) {
1911       *esr = ((__sanitizer_esr_context *)ctx)->esr;
1912       return true;
1913     }
1914     aux += ctx->size;
1915   }
1916   return false;
1917 }
1918 #elif SANITIZER_FREEBSD && defined(__aarch64__)
1919 // FreeBSD doesn't provide ESR in the ucontext.
1920 static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
1921   return false;
1922 }
1923 #endif
1924 
1925 using Context = ucontext_t;
1926 
1927 SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
1928   Context *ucontext = (Context *)context;
1929 #if defined(__x86_64__) || defined(__i386__)
1930   static const uptr PF_WRITE = 1U << 1;
1931 #if SANITIZER_FREEBSD
1932   uptr err = ucontext->uc_mcontext.mc_err;
1933 #elif SANITIZER_NETBSD
1934   uptr err = ucontext->uc_mcontext.__gregs[_REG_ERR];
1935 #elif SANITIZER_SOLARIS && defined(__i386__)
1936   const int Err = 13;
1937   uptr err = ucontext->uc_mcontext.gregs[Err];
1938 #else
1939   uptr err = ucontext->uc_mcontext.gregs[REG_ERR];
1940 #endif // SANITIZER_FREEBSD
1941   return err & PF_WRITE ? Write : Read;
1942 #elif defined(__mips__)
1943   uint32_t *exception_source;
1944   uint32_t faulty_instruction;
1945   uint32_t op_code;
1946 
1947   exception_source = (uint32_t *)ucontext->uc_mcontext.pc;
1948   faulty_instruction = (uint32_t)(*exception_source);
1949 
1950   op_code = (faulty_instruction >> 26) & 0x3f;
1951 
1952   // FIXME: Add support for FPU, microMIPS, DSP, MSA memory instructions.
1953   switch (op_code) {
1954     case 0x28:  // sb
1955     case 0x29:  // sh
1956     case 0x2b:  // sw
1957     case 0x3f:  // sd
1958 #if __mips_isa_rev < 6
1959     case 0x2c:  // sdl
1960     case 0x2d:  // sdr
1961     case 0x2a:  // swl
1962     case 0x2e:  // swr
1963 #endif
1964       return SignalContext::Write;
1965 
1966     case 0x20:  // lb
1967     case 0x24:  // lbu
1968     case 0x21:  // lh
1969     case 0x25:  // lhu
1970     case 0x23:  // lw
1971     case 0x27:  // lwu
1972     case 0x37:  // ld
1973 #if __mips_isa_rev < 6
1974     case 0x1a:  // ldl
1975     case 0x1b:  // ldr
1976     case 0x22:  // lwl
1977     case 0x26:  // lwr
1978 #endif
1979       return SignalContext::Read;
1980 #if __mips_isa_rev == 6
1981     case 0x3b:  // pcrel
1982       op_code = (faulty_instruction >> 19) & 0x3;
1983       switch (op_code) {
1984         case 0x1:  // lwpc
1985         case 0x2:  // lwupc
1986           return SignalContext::Read;
1987       }
1988 #endif
1989   }
1990   return SignalContext::Unknown;
1991 #elif defined(__arm__)
1992   static const uptr FSR_WRITE = 1U << 11;
1993   uptr fsr = ucontext->uc_mcontext.error_code;
1994   return fsr & FSR_WRITE ? Write : Read;
1995 #elif defined(__aarch64__)
1996   static const u64 ESR_ELx_WNR = 1U << 6;
1997   u64 esr;
1998   if (!Aarch64GetESR(ucontext, &esr)) return Unknown;
1999   return esr & ESR_ELx_WNR ? Write : Read;
2000 #elif defined(__loongarch__)
2001   u32 flags = ucontext->uc_mcontext.__flags;
2002   if (flags & SC_ADDRERR_RD)
2003     return SignalContext::Read;
2004   if (flags & SC_ADDRERR_WR)
2005     return SignalContext::Write;
2006   return SignalContext::Unknown;
2007 #elif defined(__sparc__)
2008   // Decode the instruction to determine the access type.
2009   // From OpenSolaris $SRC/uts/sun4/os/trap.c (get_accesstype).
2010 #if SANITIZER_SOLARIS
2011   uptr pc = ucontext->uc_mcontext.gregs[REG_PC];
2012 #else
2013   // Historical BSDism here.
2014   struct sigcontext *scontext = (struct sigcontext *)context;
2015 #if defined(__arch64__)
2016   uptr pc = scontext->sigc_regs.tpc;
2017 #else
2018   uptr pc = scontext->si_regs.pc;
2019 #endif
2020 #endif
2021   u32 instr = *(u32 *)pc;
2022   return (instr >> 21) & 1 ? Write: Read;
2023 #elif defined(__riscv)
2024 #if SANITIZER_FREEBSD
2025   unsigned long pc = ucontext->uc_mcontext.mc_gpregs.gp_sepc;
2026 #else
2027   unsigned long pc = ucontext->uc_mcontext.__gregs[REG_PC];
2028 #endif
2029   unsigned faulty_instruction = *(uint16_t *)pc;
2030 
2031 #if defined(__riscv_compressed)
2032   if ((faulty_instruction & 0x3) != 0x3) {  // it's a compressed instruction
2033     // set op_bits to the instruction bits [1, 0, 15, 14, 13]
2034     unsigned op_bits =
2035         ((faulty_instruction & 0x3) << 3) | (faulty_instruction >> 13);
2036     unsigned rd = faulty_instruction & 0xF80;  // bits 7-11, inclusive
2037     switch (op_bits) {
2038       case 0b10'010:  // c.lwsp (rd != x0)
2039 #if __riscv_xlen == 64
2040       case 0b10'011:  // c.ldsp (rd != x0)
2041 #endif
2042         return rd ? SignalContext::Read : SignalContext::Unknown;
2043       case 0b00'010:  // c.lw
2044 #if __riscv_flen >= 32 && __riscv_xlen == 32
2045       case 0b10'011:  // c.flwsp
2046 #endif
2047 #if __riscv_flen >= 32 || __riscv_xlen == 64
2048       case 0b00'011:  // c.flw / c.ld
2049 #endif
2050 #if __riscv_flen == 64
2051       case 0b00'001:  // c.fld
2052       case 0b10'001:  // c.fldsp
2053 #endif
2054         return SignalContext::Read;
2055       case 0b00'110:  // c.sw
2056       case 0b10'110:  // c.swsp
2057 #if __riscv_flen >= 32 || __riscv_xlen == 64
2058       case 0b00'111:  // c.fsw / c.sd
2059       case 0b10'111:  // c.fswsp / c.sdsp
2060 #endif
2061 #if __riscv_flen == 64
2062       case 0b00'101:  // c.fsd
2063       case 0b10'101:  // c.fsdsp
2064 #endif
2065         return SignalContext::Write;
2066       default:
2067         return SignalContext::Unknown;
2068     }
2069   }
2070 #endif
2071 
2072   unsigned opcode = faulty_instruction & 0x7f;         // lower 7 bits
2073   unsigned funct3 = (faulty_instruction >> 12) & 0x7;  // bits 12-14, inclusive
2074   switch (opcode) {
2075     case 0b0000011:  // loads
2076       switch (funct3) {
2077         case 0b000:  // lb
2078         case 0b001:  // lh
2079         case 0b010:  // lw
2080 #if __riscv_xlen == 64
2081         case 0b011:  // ld
2082 #endif
2083         case 0b100:  // lbu
2084         case 0b101:  // lhu
2085           return SignalContext::Read;
2086         default:
2087           return SignalContext::Unknown;
2088       }
2089     case 0b0100011:  // stores
2090       switch (funct3) {
2091         case 0b000:  // sb
2092         case 0b001:  // sh
2093         case 0b010:  // sw
2094 #if __riscv_xlen == 64
2095         case 0b011:  // sd
2096 #endif
2097           return SignalContext::Write;
2098         default:
2099           return SignalContext::Unknown;
2100       }
2101 #if __riscv_flen >= 32
2102     case 0b0000111:  // floating-point loads
2103       switch (funct3) {
2104         case 0b010:  // flw
2105 #if __riscv_flen == 64
2106         case 0b011:  // fld
2107 #endif
2108           return SignalContext::Read;
2109         default:
2110           return SignalContext::Unknown;
2111       }
2112     case 0b0100111:  // floating-point stores
2113       switch (funct3) {
2114         case 0b010:  // fsw
2115 #if __riscv_flen == 64
2116         case 0b011:  // fsd
2117 #endif
2118           return SignalContext::Write;
2119         default:
2120           return SignalContext::Unknown;
2121       }
2122 #endif
2123     default:
2124       return SignalContext::Unknown;
2125   }
2126 #else
2127   (void)ucontext;
2128   return Unknown;  // FIXME: Implement.
2129 #endif
2130 }
2131 
2132 bool SignalContext::IsTrueFaultingAddress() const {
2133   auto si = static_cast<const siginfo_t *>(siginfo);
2134   // SIGSEGV signals without a true fault address have si_code set to 128.
2135   return si->si_signo == SIGSEGV && si->si_code != 128;
2136 }
2137 
2138 void SignalContext::DumpAllRegisters(void *context) {
2139   // FIXME: Implement this.
2140 }
2141 
2142 static void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
2143 #if SANITIZER_NETBSD
2144   // This covers all NetBSD architectures
2145   ucontext_t *ucontext = (ucontext_t *)context;
2146   *pc = _UC_MACHINE_PC(ucontext);
2147   *bp = _UC_MACHINE_FP(ucontext);
2148   *sp = _UC_MACHINE_SP(ucontext);
2149 #elif defined(__arm__)
2150   ucontext_t *ucontext = (ucontext_t*)context;
2151   *pc = ucontext->uc_mcontext.arm_pc;
2152   *bp = ucontext->uc_mcontext.arm_fp;
2153   *sp = ucontext->uc_mcontext.arm_sp;
2154 #elif defined(__aarch64__)
2155 # if SANITIZER_FREEBSD
2156   ucontext_t *ucontext = (ucontext_t*)context;
2157   *pc = ucontext->uc_mcontext.mc_gpregs.gp_elr;
2158   *bp = ucontext->uc_mcontext.mc_gpregs.gp_x[29];
2159   *sp = ucontext->uc_mcontext.mc_gpregs.gp_sp;
2160 # else
2161   ucontext_t *ucontext = (ucontext_t*)context;
2162   *pc = ucontext->uc_mcontext.pc;
2163   *bp = ucontext->uc_mcontext.regs[29];
2164   *sp = ucontext->uc_mcontext.sp;
2165 # endif
2166 #elif defined(__hppa__)
2167   ucontext_t *ucontext = (ucontext_t*)context;
2168   *pc = ucontext->uc_mcontext.sc_iaoq[0];
2169   /* GCC uses %r3 whenever a frame pointer is needed.  */
2170   *bp = ucontext->uc_mcontext.sc_gr[3];
2171   *sp = ucontext->uc_mcontext.sc_gr[30];
2172 #elif defined(__x86_64__)
2173 # if SANITIZER_FREEBSD
2174   ucontext_t *ucontext = (ucontext_t*)context;
2175   *pc = ucontext->uc_mcontext.mc_rip;
2176   *bp = ucontext->uc_mcontext.mc_rbp;
2177   *sp = ucontext->uc_mcontext.mc_rsp;
2178 # else
2179   ucontext_t *ucontext = (ucontext_t*)context;
2180   *pc = ucontext->uc_mcontext.gregs[REG_RIP];
2181   *bp = ucontext->uc_mcontext.gregs[REG_RBP];
2182   *sp = ucontext->uc_mcontext.gregs[REG_RSP];
2183 # endif
2184 #elif defined(__i386__)
2185 # if SANITIZER_FREEBSD
2186   ucontext_t *ucontext = (ucontext_t*)context;
2187   *pc = ucontext->uc_mcontext.mc_eip;
2188   *bp = ucontext->uc_mcontext.mc_ebp;
2189   *sp = ucontext->uc_mcontext.mc_esp;
2190 # else
2191   ucontext_t *ucontext = (ucontext_t*)context;
2192 # if SANITIZER_SOLARIS
2193   /* Use the numeric values: the symbolic ones are undefined by llvm
2194      include/llvm/Support/Solaris.h.  */
2195 # ifndef REG_EIP
2196 #  define REG_EIP 14 // REG_PC
2197 # endif
2198 # ifndef REG_EBP
2199 #  define REG_EBP  6 // REG_FP
2200 # endif
2201 # ifndef REG_UESP
2202 #  define REG_UESP 17 // REG_SP
2203 # endif
2204 # endif
2205   *pc = ucontext->uc_mcontext.gregs[REG_EIP];
2206   *bp = ucontext->uc_mcontext.gregs[REG_EBP];
2207   *sp = ucontext->uc_mcontext.gregs[REG_UESP];
2208 # endif
2209 #elif defined(__powerpc__) || defined(__powerpc64__)
2210 #    if SANITIZER_FREEBSD
2211   ucontext_t *ucontext = (ucontext_t *)context;
2212   *pc = ucontext->uc_mcontext.mc_srr0;
2213   *sp = ucontext->uc_mcontext.mc_frame[1];
2214   *bp = ucontext->uc_mcontext.mc_frame[31];
2215 #    else
2216   ucontext_t *ucontext = (ucontext_t*)context;
2217   *pc = ucontext->uc_mcontext.regs->nip;
2218   *sp = ucontext->uc_mcontext.regs->gpr[PT_R1];
2219   // The powerpc{,64}-linux ABIs do not specify r31 as the frame
2220   // pointer, but GCC always uses r31 when we need a frame pointer.
2221   *bp = ucontext->uc_mcontext.regs->gpr[PT_R31];
2222 #    endif
2223 #elif defined(__sparc__)
2224 #if defined(__arch64__) || defined(__sparcv9)
2225 #define STACK_BIAS 2047
2226 #else
2227 #define STACK_BIAS 0
2228 # endif
2229 # if SANITIZER_SOLARIS
2230   ucontext_t *ucontext = (ucontext_t *)context;
2231   *pc = ucontext->uc_mcontext.gregs[REG_PC];
2232   *sp = ucontext->uc_mcontext.gregs[REG_O6] + STACK_BIAS;
2233 #else
2234   // Historical BSDism here.
2235   struct sigcontext *scontext = (struct sigcontext *)context;
2236 #if defined(__arch64__)
2237   *pc = scontext->sigc_regs.tpc;
2238   *sp = scontext->sigc_regs.u_regs[14] + STACK_BIAS;
2239 #else
2240   *pc = scontext->si_regs.pc;
2241   *sp = scontext->si_regs.u_regs[14];
2242 #endif
2243 # endif
2244   *bp = (uptr)((uhwptr *)*sp)[14] + STACK_BIAS;
2245 #elif defined(__mips__)
2246   ucontext_t *ucontext = (ucontext_t*)context;
2247   *pc = ucontext->uc_mcontext.pc;
2248   *bp = ucontext->uc_mcontext.gregs[30];
2249   *sp = ucontext->uc_mcontext.gregs[29];
2250 #elif defined(__s390__)
2251   ucontext_t *ucontext = (ucontext_t*)context;
2252 # if defined(__s390x__)
2253   *pc = ucontext->uc_mcontext.psw.addr;
2254 # else
2255   *pc = ucontext->uc_mcontext.psw.addr & 0x7fffffff;
2256 # endif
2257   *bp = ucontext->uc_mcontext.gregs[11];
2258   *sp = ucontext->uc_mcontext.gregs[15];
2259 #elif defined(__riscv)
2260   ucontext_t *ucontext = (ucontext_t*)context;
2261 #    if SANITIZER_FREEBSD
2262   *pc = ucontext->uc_mcontext.mc_gpregs.gp_sepc;
2263   *bp = ucontext->uc_mcontext.mc_gpregs.gp_s[0];
2264   *sp = ucontext->uc_mcontext.mc_gpregs.gp_sp;
2265 #    else
2266   *pc = ucontext->uc_mcontext.__gregs[REG_PC];
2267   *bp = ucontext->uc_mcontext.__gregs[REG_S0];
2268   *sp = ucontext->uc_mcontext.__gregs[REG_SP];
2269 #    endif
2270 #  elif defined(__hexagon__)
2271   ucontext_t *ucontext = (ucontext_t *)context;
2272   *pc = ucontext->uc_mcontext.pc;
2273   *bp = ucontext->uc_mcontext.r30;
2274   *sp = ucontext->uc_mcontext.r29;
2275 #  elif defined(__loongarch__)
2276   ucontext_t *ucontext = (ucontext_t *)context;
2277   *pc = ucontext->uc_mcontext.__pc;
2278   *bp = ucontext->uc_mcontext.__gregs[22];
2279   *sp = ucontext->uc_mcontext.__gregs[3];
2280 #  else
2281 #    error "Unsupported arch"
2282 #  endif
2283 }
2284 
2285 void SignalContext::InitPcSpBp() { GetPcSpBp(context, &pc, &sp, &bp); }
2286 
2287 void InitializePlatformEarly() {
2288   // Do nothing.
2289 }
2290 
2291 void CheckASLR() {
2292 #if SANITIZER_NETBSD
2293   int mib[3];
2294   int paxflags;
2295   uptr len = sizeof(paxflags);
2296 
2297   mib[0] = CTL_PROC;
2298   mib[1] = internal_getpid();
2299   mib[2] = PROC_PID_PAXFLAGS;
2300 
2301   if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2302     Printf("sysctl failed\n");
2303     Die();
2304   }
2305 
2306   if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_ASLR)) {
2307     Printf("This sanitizer is not compatible with enabled ASLR.\n"
2308            "To disable ASLR, please run \"paxctl +a %s\" and try again.\n",
2309            GetArgv()[0]);
2310     Die();
2311   }
2312 #elif SANITIZER_FREEBSD
2313   int aslr_status;
2314   int r = internal_procctl(P_PID, 0, PROC_ASLR_STATUS, &aslr_status);
2315   if (UNLIKELY(r == -1)) {
2316     // We're making things less 'dramatic' here since
2317     // the cmd is not necessarily guaranteed to be here
2318     // just yet regarding FreeBSD release
2319     return;
2320   }
2321   if ((aslr_status & PROC_ASLR_ACTIVE) != 0) {
2322     VReport(1, "This sanitizer is not compatible with enabled ASLR "
2323                "and binaries compiled with PIE\n"
2324                "ASLR will be disabled and the program re-executed.\n");
2325     int aslr_ctl = PROC_ASLR_FORCE_DISABLE;
2326     CHECK_NE(procctl(P_PID, 0, PROC_ASLR_CTL, &aslr_ctl), -1);
2327     ReExec();
2328   }
2329 #  elif SANITIZER_PPC64V2
2330   // Disable ASLR for Linux PPC64LE.
2331   int old_personality = personality(0xffffffff);
2332   if (old_personality != -1 && (old_personality & ADDR_NO_RANDOMIZE) == 0) {
2333     VReport(1,
2334             "WARNING: Program is being run with address space layout "
2335             "randomization (ASLR) enabled which prevents the thread and "
2336             "memory sanitizers from working on powerpc64le.\n"
2337             "ASLR will be disabled and the program re-executed.\n");
2338     CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
2339     ReExec();
2340   }
2341 #  else
2342   // Do nothing
2343 #  endif
2344 }
2345 
2346 void CheckMPROTECT() {
2347 #if SANITIZER_NETBSD
2348   int mib[3];
2349   int paxflags;
2350   uptr len = sizeof(paxflags);
2351 
2352   mib[0] = CTL_PROC;
2353   mib[1] = internal_getpid();
2354   mib[2] = PROC_PID_PAXFLAGS;
2355 
2356   if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2357     Printf("sysctl failed\n");
2358     Die();
2359   }
2360 
2361   if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_MPROTECT)) {
2362     Printf("This sanitizer is not compatible with enabled MPROTECT\n");
2363     Die();
2364   }
2365 #else
2366   // Do nothing
2367 #endif
2368 }
2369 
2370 void CheckNoDeepBind(const char *filename, int flag) {
2371 #ifdef RTLD_DEEPBIND
2372   if (flag & RTLD_DEEPBIND) {
2373     Report(
2374         "You are trying to dlopen a %s shared library with RTLD_DEEPBIND flag"
2375         " which is incompatible with sanitizer runtime "
2376         "(see https://github.com/google/sanitizers/issues/611 for details"
2377         "). If you want to run %s library under sanitizers please remove "
2378         "RTLD_DEEPBIND from dlopen flags.\n",
2379         filename, filename);
2380     Die();
2381   }
2382 #endif
2383 }
2384 
2385 uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
2386                               uptr *largest_gap_found,
2387                               uptr *max_occupied_addr) {
2388   UNREACHABLE("FindAvailableMemoryRange is not available");
2389   return 0;
2390 }
2391 
2392 bool GetRandom(void *buffer, uptr length, bool blocking) {
2393   if (!buffer || !length || length > 256)
2394     return false;
2395 #if SANITIZER_USE_GETENTROPY
2396   uptr rnd = getentropy(buffer, length);
2397   int rverrno = 0;
2398   if (internal_iserror(rnd, &rverrno) && rverrno == EFAULT)
2399     return false;
2400   else if (rnd == 0)
2401     return true;
2402 #endif // SANITIZER_USE_GETENTROPY
2403 
2404 #if SANITIZER_USE_GETRANDOM
2405   static atomic_uint8_t skip_getrandom_syscall;
2406   if (!atomic_load_relaxed(&skip_getrandom_syscall)) {
2407     // Up to 256 bytes, getrandom will not be interrupted.
2408     uptr res = internal_syscall(SYSCALL(getrandom), buffer, length,
2409                                 blocking ? 0 : GRND_NONBLOCK);
2410     int rverrno = 0;
2411     if (internal_iserror(res, &rverrno) && rverrno == ENOSYS)
2412       atomic_store_relaxed(&skip_getrandom_syscall, 1);
2413     else if (res == length)
2414       return true;
2415   }
2416 #endif // SANITIZER_USE_GETRANDOM
2417   // Up to 256 bytes, a read off /dev/urandom will not be interrupted.
2418   // blocking is moot here, O_NONBLOCK has no effect when opening /dev/urandom.
2419   uptr fd = internal_open("/dev/urandom", O_RDONLY);
2420   if (internal_iserror(fd))
2421     return false;
2422   uptr res = internal_read(fd, buffer, length);
2423   if (internal_iserror(res))
2424     return false;
2425   internal_close(fd);
2426   return true;
2427 }
2428 
2429 } // namespace __sanitizer
2430 
2431 #endif
2432