xref: /freebsd/contrib/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp (revision 62cfcf62f627e5093fb37026a6d8c98e4d2ef04c)
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_OPENBSD || 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
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 defined(__mips64)
38 #include <asm/unistd.h>
39 #include <sys/types.h>
40 #define stat kernel_stat
41 #include <asm/stat.h>
42 #undef stat
43 #endif
44 
45 #include <dlfcn.h>
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <link.h>
49 #include <pthread.h>
50 #include <sched.h>
51 #include <signal.h>
52 #include <sys/mman.h>
53 #include <sys/param.h>
54 #if !SANITIZER_SOLARIS
55 #include <sys/ptrace.h>
56 #endif
57 #include <sys/resource.h>
58 #include <sys/stat.h>
59 #include <sys/syscall.h>
60 #include <sys/time.h>
61 #include <sys/types.h>
62 #if !SANITIZER_OPENBSD
63 #include <ucontext.h>
64 #endif
65 #if SANITIZER_OPENBSD
66 #include <sys/futex.h>
67 #include <sys/sysctl.h>
68 #endif
69 #include <unistd.h>
70 
71 #if SANITIZER_LINUX
72 #include <sys/utsname.h>
73 #endif
74 
75 #if SANITIZER_LINUX && !SANITIZER_ANDROID
76 #include <sys/personality.h>
77 #endif
78 
79 #if SANITIZER_FREEBSD
80 #include <sys/exec.h>
81 #include <sys/sysctl.h>
82 #include <machine/atomic.h>
83 extern "C" {
84 // <sys/umtx.h> must be included after <errno.h> and <sys/types.h> on
85 // FreeBSD 9.2 and 10.0.
86 #include <sys/umtx.h>
87 }
88 #include <sys/thr.h>
89 #endif  // SANITIZER_FREEBSD
90 
91 #if SANITIZER_NETBSD
92 #include <limits.h>  // For NAME_MAX
93 #include <sys/sysctl.h>
94 #include <sys/exec.h>
95 extern struct ps_strings *__ps_strings;
96 #endif  // SANITIZER_NETBSD
97 
98 #if SANITIZER_SOLARIS
99 #include <stdlib.h>
100 #include <thread.h>
101 #define environ _environ
102 #endif
103 
104 extern char **environ;
105 
106 #if SANITIZER_LINUX
107 // <linux/time.h>
108 struct kernel_timeval {
109   long tv_sec;
110   long tv_usec;
111 };
112 
113 // <linux/futex.h> is broken on some linux distributions.
114 const int FUTEX_WAIT = 0;
115 const int FUTEX_WAKE = 1;
116 const int FUTEX_PRIVATE_FLAG = 128;
117 const int FUTEX_WAIT_PRIVATE = FUTEX_WAIT | FUTEX_PRIVATE_FLAG;
118 const int FUTEX_WAKE_PRIVATE = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
119 #endif  // SANITIZER_LINUX
120 
121 // Are we using 32-bit or 64-bit Linux syscalls?
122 // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
123 // but it still needs to use 64-bit syscalls.
124 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__powerpc64__) ||       \
125                         SANITIZER_WORDSIZE == 64)
126 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
127 #else
128 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
129 #endif
130 
131 // Note : FreeBSD had implemented both
132 // Linux and OpenBSD apis, available from
133 // future 12.x version most likely
134 #if SANITIZER_LINUX && defined(__NR_getrandom)
135 # if !defined(GRND_NONBLOCK)
136 #  define GRND_NONBLOCK 1
137 # endif
138 # define SANITIZER_USE_GETRANDOM 1
139 #else
140 # define SANITIZER_USE_GETRANDOM 0
141 #endif  // SANITIZER_LINUX && defined(__NR_getrandom)
142 
143 #if SANITIZER_OPENBSD
144 # define SANITIZER_USE_GETENTROPY 1
145 #else
146 # if SANITIZER_FREEBSD && __FreeBSD_version >= 1200000
147 #   define SANITIZER_USE_GETENTROPY 1
148 # else
149 #   define SANITIZER_USE_GETENTROPY 0
150 # endif
151 #endif // SANITIZER_USE_GETENTROPY
152 
153 namespace __sanitizer {
154 
155 #if SANITIZER_LINUX && defined(__x86_64__)
156 #include "sanitizer_syscall_linux_x86_64.inc"
157 #elif SANITIZER_LINUX && defined(__aarch64__)
158 #include "sanitizer_syscall_linux_aarch64.inc"
159 #elif SANITIZER_LINUX && defined(__arm__)
160 #include "sanitizer_syscall_linux_arm.inc"
161 #else
162 #include "sanitizer_syscall_generic.inc"
163 #endif
164 
165 // --------------- sanitizer_libc.h
166 #if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
167 #if !SANITIZER_S390 && !SANITIZER_OPENBSD
168 uptr internal_mmap(void *addr, uptr length, int prot, int flags, int fd,
169                    u64 offset) {
170 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
171   return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
172                           offset);
173 #else
174   // mmap2 specifies file offset in 4096-byte units.
175   CHECK(IsAligned(offset, 4096));
176   return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
177                           offset / 4096);
178 #endif
179 }
180 #endif // !SANITIZER_S390 && !SANITIZER_OPENBSD
181 
182 #if !SANITIZER_OPENBSD
183 uptr internal_munmap(void *addr, uptr length) {
184   return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
185 }
186 
187 int internal_mprotect(void *addr, uptr length, int prot) {
188   return internal_syscall(SYSCALL(mprotect), (uptr)addr, length, prot);
189 }
190 #endif
191 
192 uptr internal_close(fd_t fd) {
193   return internal_syscall(SYSCALL(close), fd);
194 }
195 
196 uptr internal_open(const char *filename, int flags) {
197 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
198   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags);
199 #else
200   return internal_syscall(SYSCALL(open), (uptr)filename, flags);
201 #endif
202 }
203 
204 uptr internal_open(const char *filename, int flags, u32 mode) {
205 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
206   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags,
207                           mode);
208 #else
209   return internal_syscall(SYSCALL(open), (uptr)filename, flags, mode);
210 #endif
211 }
212 
213 uptr internal_read(fd_t fd, void *buf, uptr count) {
214   sptr res;
215   HANDLE_EINTR(res,
216                (sptr)internal_syscall(SYSCALL(read), fd, (uptr)buf, count));
217   return res;
218 }
219 
220 uptr internal_write(fd_t fd, const void *buf, uptr count) {
221   sptr res;
222   HANDLE_EINTR(res,
223                (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf, count));
224   return res;
225 }
226 
227 uptr internal_ftruncate(fd_t fd, uptr size) {
228   sptr res;
229   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd,
230                (OFF_T)size));
231   return res;
232 }
233 
234 #if !SANITIZER_LINUX_USES_64BIT_SYSCALLS && SANITIZER_LINUX
235 static void stat64_to_stat(struct stat64 *in, struct stat *out) {
236   internal_memset(out, 0, sizeof(*out));
237   out->st_dev = in->st_dev;
238   out->st_ino = in->st_ino;
239   out->st_mode = in->st_mode;
240   out->st_nlink = in->st_nlink;
241   out->st_uid = in->st_uid;
242   out->st_gid = in->st_gid;
243   out->st_rdev = in->st_rdev;
244   out->st_size = in->st_size;
245   out->st_blksize = in->st_blksize;
246   out->st_blocks = in->st_blocks;
247   out->st_atime = in->st_atime;
248   out->st_mtime = in->st_mtime;
249   out->st_ctime = in->st_ctime;
250 }
251 #endif
252 
253 #if defined(__mips64)
254 // Undefine compatibility macros from <sys/stat.h>
255 // so that they would not clash with the kernel_stat
256 // st_[a|m|c]time fields
257 #undef st_atime
258 #undef st_mtime
259 #undef st_ctime
260 #if defined(SANITIZER_ANDROID)
261 // Bionic sys/stat.h defines additional macros
262 // for compatibility with the old NDKs and
263 // they clash with the kernel_stat structure
264 // st_[a|m|c]time_nsec fields.
265 #undef st_atime_nsec
266 #undef st_mtime_nsec
267 #undef st_ctime_nsec
268 #endif
269 static void kernel_stat_to_stat(struct kernel_stat *in, struct stat *out) {
270   internal_memset(out, 0, sizeof(*out));
271   out->st_dev = in->st_dev;
272   out->st_ino = in->st_ino;
273   out->st_mode = in->st_mode;
274   out->st_nlink = in->st_nlink;
275   out->st_uid = in->st_uid;
276   out->st_gid = in->st_gid;
277   out->st_rdev = in->st_rdev;
278   out->st_size = in->st_size;
279   out->st_blksize = in->st_blksize;
280   out->st_blocks = in->st_blocks;
281 #if defined(__USE_MISC)     || \
282     defined(__USE_XOPEN2K8) || \
283     defined(SANITIZER_ANDROID)
284   out->st_atim.tv_sec = in->st_atime;
285   out->st_atim.tv_nsec = in->st_atime_nsec;
286   out->st_mtim.tv_sec = in->st_mtime;
287   out->st_mtim.tv_nsec = in->st_mtime_nsec;
288   out->st_ctim.tv_sec = in->st_ctime;
289   out->st_ctim.tv_nsec = in->st_ctime_nsec;
290 #else
291   out->st_atime = in->st_atime;
292   out->st_atimensec = in->st_atime_nsec;
293   out->st_mtime = in->st_mtime;
294   out->st_mtimensec = in->st_mtime_nsec;
295   out->st_ctime = in->st_ctime;
296   out->st_atimensec = in->st_ctime_nsec;
297 #endif
298 }
299 #endif
300 
301 uptr internal_stat(const char *path, void *buf) {
302 #if SANITIZER_FREEBSD || SANITIZER_OPENBSD
303   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf, 0);
304 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
305   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
306                           0);
307 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
308 # if defined(__mips64)
309   // For mips64, stat syscall fills buffer in the format of kernel_stat
310   struct kernel_stat kbuf;
311   int res = internal_syscall(SYSCALL(stat), path, &kbuf);
312   kernel_stat_to_stat(&kbuf, (struct stat *)buf);
313   return res;
314 # else
315   return internal_syscall(SYSCALL(stat), (uptr)path, (uptr)buf);
316 # endif
317 #else
318   struct stat64 buf64;
319   int res = internal_syscall(SYSCALL(stat64), path, &buf64);
320   stat64_to_stat(&buf64, (struct stat *)buf);
321   return res;
322 #endif
323 }
324 
325 uptr internal_lstat(const char *path, void *buf) {
326 #if SANITIZER_FREEBSD || SANITIZER_OPENBSD
327   return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf,
328                           AT_SYMLINK_NOFOLLOW);
329 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
330   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
331                           AT_SYMLINK_NOFOLLOW);
332 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
333 # if SANITIZER_MIPS64
334   // For mips64, lstat syscall fills buffer in the format of kernel_stat
335   struct kernel_stat kbuf;
336   int res = internal_syscall(SYSCALL(lstat), path, &kbuf);
337   kernel_stat_to_stat(&kbuf, (struct stat *)buf);
338   return res;
339 # else
340   return internal_syscall(SYSCALL(lstat), (uptr)path, (uptr)buf);
341 # endif
342 #else
343   struct stat64 buf64;
344   int res = internal_syscall(SYSCALL(lstat64), path, &buf64);
345   stat64_to_stat(&buf64, (struct stat *)buf);
346   return res;
347 #endif
348 }
349 
350 uptr internal_fstat(fd_t fd, void *buf) {
351 #if SANITIZER_FREEBSD || SANITIZER_OPENBSD || \
352     SANITIZER_LINUX_USES_64BIT_SYSCALLS
353 #if SANITIZER_MIPS64 && !SANITIZER_OPENBSD
354   // For mips64, fstat syscall fills buffer in the format of kernel_stat
355   struct kernel_stat kbuf;
356   int res = internal_syscall(SYSCALL(fstat), fd, &kbuf);
357   kernel_stat_to_stat(&kbuf, (struct stat *)buf);
358   return res;
359 # else
360   return internal_syscall(SYSCALL(fstat), fd, (uptr)buf);
361 # endif
362 #else
363   struct stat64 buf64;
364   int res = internal_syscall(SYSCALL(fstat64), fd, &buf64);
365   stat64_to_stat(&buf64, (struct stat *)buf);
366   return res;
367 #endif
368 }
369 
370 uptr internal_filesize(fd_t fd) {
371   struct stat st;
372   if (internal_fstat(fd, &st))
373     return -1;
374   return (uptr)st.st_size;
375 }
376 
377 uptr internal_dup(int oldfd) {
378   return internal_syscall(SYSCALL(dup), oldfd);
379 }
380 
381 uptr internal_dup2(int oldfd, int newfd) {
382 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
383   return internal_syscall(SYSCALL(dup3), oldfd, newfd, 0);
384 #else
385   return internal_syscall(SYSCALL(dup2), oldfd, newfd);
386 #endif
387 }
388 
389 uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
390 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
391   return internal_syscall(SYSCALL(readlinkat), AT_FDCWD, (uptr)path, (uptr)buf,
392                           bufsize);
393 #elif SANITIZER_OPENBSD
394   return internal_syscall(SYSCALL(readlinkat), AT_FDCWD, (uptr)path, (uptr)buf,
395                           bufsize);
396 #else
397   return internal_syscall(SYSCALL(readlink), (uptr)path, (uptr)buf, bufsize);
398 #endif
399 }
400 
401 uptr internal_unlink(const char *path) {
402 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS || SANITIZER_OPENBSD
403   return internal_syscall(SYSCALL(unlinkat), AT_FDCWD, (uptr)path, 0);
404 #else
405   return internal_syscall(SYSCALL(unlink), (uptr)path);
406 #endif
407 }
408 
409 uptr internal_rename(const char *oldpath, const char *newpath) {
410 #if defined(__riscv)
411   return internal_syscall(SYSCALL(renameat2), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
412                           (uptr)newpath, 0);
413 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS || SANITIZER_OPENBSD
414   return internal_syscall(SYSCALL(renameat), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
415                           (uptr)newpath);
416 #else
417   return internal_syscall(SYSCALL(rename), (uptr)oldpath, (uptr)newpath);
418 #endif
419 }
420 
421 uptr internal_sched_yield() {
422   return internal_syscall(SYSCALL(sched_yield));
423 }
424 
425 void internal__exit(int exitcode) {
426 #if SANITIZER_FREEBSD || SANITIZER_OPENBSD
427   internal_syscall(SYSCALL(exit), exitcode);
428 #else
429   internal_syscall(SYSCALL(exit_group), exitcode);
430 #endif
431   Die();  // Unreachable.
432 }
433 
434 unsigned int internal_sleep(unsigned int seconds) {
435   struct timespec ts;
436   ts.tv_sec = seconds;
437   ts.tv_nsec = 0;
438   int res = internal_syscall(SYSCALL(nanosleep), &ts, &ts);
439   if (res) return ts.tv_sec;
440   return 0;
441 }
442 
443 uptr internal_execve(const char *filename, char *const argv[],
444                      char *const envp[]) {
445   return internal_syscall(SYSCALL(execve), (uptr)filename, (uptr)argv,
446                           (uptr)envp);
447 }
448 #endif  // !SANITIZER_SOLARIS && !SANITIZER_NETBSD
449 
450 // ----------------- sanitizer_common.h
451 bool FileExists(const char *filename) {
452   if (ShouldMockFailureToOpen(filename))
453     return false;
454   struct stat st;
455 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
456   if (internal_syscall(SYSCALL(newfstatat), AT_FDCWD, filename, &st, 0))
457 #else
458   if (internal_stat(filename, &st))
459 #endif
460     return false;
461   // Sanity check: filename is a regular file.
462   return S_ISREG(st.st_mode);
463 }
464 
465 #if !SANITIZER_NETBSD
466 tid_t GetTid() {
467 #if SANITIZER_FREEBSD
468   long Tid;
469   thr_self(&Tid);
470   return Tid;
471 #elif SANITIZER_OPENBSD
472   return internal_syscall(SYSCALL(getthrid));
473 #elif SANITIZER_SOLARIS
474   return thr_self();
475 #else
476   return internal_syscall(SYSCALL(gettid));
477 #endif
478 }
479 
480 int TgKill(pid_t pid, tid_t tid, int sig) {
481 #if SANITIZER_LINUX
482   return internal_syscall(SYSCALL(tgkill), pid, tid, sig);
483 #elif SANITIZER_FREEBSD
484   return internal_syscall(SYSCALL(thr_kill2), pid, tid, sig);
485 #elif SANITIZER_OPENBSD
486   (void)pid;
487   return internal_syscall(SYSCALL(thrkill), tid, sig, nullptr);
488 #elif SANITIZER_SOLARIS
489   (void)pid;
490   return thr_kill(tid, sig);
491 #endif
492 }
493 #endif
494 
495 #if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
496 u64 NanoTime() {
497 #if SANITIZER_FREEBSD || SANITIZER_OPENBSD
498   timeval tv;
499 #else
500   kernel_timeval tv;
501 #endif
502   internal_memset(&tv, 0, sizeof(tv));
503   internal_syscall(SYSCALL(gettimeofday), &tv, 0);
504   return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
505 }
506 
507 uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp) {
508   return internal_syscall(SYSCALL(clock_gettime), clk_id, tp);
509 }
510 #endif  // !SANITIZER_SOLARIS && !SANITIZER_NETBSD
511 
512 // Like getenv, but reads env directly from /proc (on Linux) or parses the
513 // 'environ' array (on some others) and does not use libc. This function
514 // should be called first inside __asan_init.
515 const char *GetEnv(const char *name) {
516 #if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD || \
517     SANITIZER_SOLARIS
518   if (::environ != 0) {
519     uptr NameLen = internal_strlen(name);
520     for (char **Env = ::environ; *Env != 0; Env++) {
521       if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
522         return (*Env) + NameLen + 1;
523     }
524   }
525   return 0;  // Not found.
526 #elif SANITIZER_LINUX
527   static char *environ;
528   static uptr len;
529   static bool inited;
530   if (!inited) {
531     inited = true;
532     uptr environ_size;
533     if (!ReadFileToBuffer("/proc/self/environ", &environ, &environ_size, &len))
534       environ = nullptr;
535   }
536   if (!environ || len == 0) return nullptr;
537   uptr namelen = internal_strlen(name);
538   const char *p = environ;
539   while (*p != '\0') {  // will happen at the \0\0 that terminates the buffer
540     // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
541     const char* endp =
542         (char*)internal_memchr(p, '\0', len - (p - environ));
543     if (!endp)  // this entry isn't NUL terminated
544       return nullptr;
545     else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=')  // Match.
546       return p + namelen + 1;  // point after =
547     p = endp + 1;
548   }
549   return nullptr;  // Not found.
550 #else
551 #error "Unsupported platform"
552 #endif
553 }
554 
555 #if !SANITIZER_FREEBSD && !SANITIZER_NETBSD && !SANITIZER_OPENBSD
556 extern "C" {
557 SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
558 }
559 #endif
560 
561 #if !SANITIZER_GO && !SANITIZER_FREEBSD && !SANITIZER_NETBSD &&                \
562     !SANITIZER_OPENBSD
563 static void ReadNullSepFileToArray(const char *path, char ***arr,
564                                    int arr_size) {
565   char *buff;
566   uptr buff_size;
567   uptr buff_len;
568   *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
569   if (!ReadFileToBuffer(path, &buff, &buff_size, &buff_len, 1024 * 1024)) {
570     (*arr)[0] = nullptr;
571     return;
572   }
573   (*arr)[0] = buff;
574   int count, i;
575   for (count = 1, i = 1; ; i++) {
576     if (buff[i] == 0) {
577       if (buff[i+1] == 0) break;
578       (*arr)[count] = &buff[i+1];
579       CHECK_LE(count, arr_size - 1);  // FIXME: make this more flexible.
580       count++;
581     }
582   }
583   (*arr)[count] = nullptr;
584 }
585 #endif
586 
587 #if !SANITIZER_OPENBSD
588 static void GetArgsAndEnv(char ***argv, char ***envp) {
589 #if SANITIZER_FREEBSD
590   // On FreeBSD, retrieving the argument and environment arrays is done via the
591   // kern.ps_strings sysctl, which returns a pointer to a structure containing
592   // this information. See also <sys/exec.h>.
593   ps_strings *pss;
594   uptr sz = sizeof(pss);
595   if (internal_sysctlbyname("kern.ps_strings", &pss, &sz, NULL, 0) == -1) {
596     Printf("sysctl kern.ps_strings failed\n");
597     Die();
598   }
599   *argv = pss->ps_argvstr;
600   *envp = pss->ps_envstr;
601 #elif SANITIZER_NETBSD
602   *argv = __ps_strings->ps_argvstr;
603   *envp = __ps_strings->ps_envstr;
604 #else // SANITIZER_FREEBSD
605 #if !SANITIZER_GO
606   if (&__libc_stack_end) {
607 #endif // !SANITIZER_GO
608     uptr* stack_end = (uptr*)__libc_stack_end;
609     int argc = *stack_end;
610     *argv = (char**)(stack_end + 1);
611     *envp = (char**)(stack_end + argc + 2);
612 #if !SANITIZER_GO
613   } else {
614     static const int kMaxArgv = 2000, kMaxEnvp = 2000;
615     ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
616     ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
617   }
618 #endif // !SANITIZER_GO
619 #endif // SANITIZER_FREEBSD
620 }
621 
622 char **GetArgv() {
623   char **argv, **envp;
624   GetArgsAndEnv(&argv, &envp);
625   return argv;
626 }
627 
628 char **GetEnviron() {
629   char **argv, **envp;
630   GetArgsAndEnv(&argv, &envp);
631   return envp;
632 }
633 
634 #endif  // !SANITIZER_OPENBSD
635 
636 #if !SANITIZER_SOLARIS
637 enum MutexState {
638   MtxUnlocked = 0,
639   MtxLocked = 1,
640   MtxSleeping = 2
641 };
642 
643 BlockingMutex::BlockingMutex() {
644   internal_memset(this, 0, sizeof(*this));
645 }
646 
647 void BlockingMutex::Lock() {
648   CHECK_EQ(owner_, 0);
649   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
650   if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked)
651     return;
652   while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) {
653 #if SANITIZER_FREEBSD
654     _umtx_op(m, UMTX_OP_WAIT_UINT, MtxSleeping, 0, 0);
655 #elif SANITIZER_NETBSD
656     sched_yield(); /* No userspace futex-like synchronization */
657 #else
658     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAIT_PRIVATE, MtxSleeping,
659                      0, 0, 0);
660 #endif
661   }
662 }
663 
664 void BlockingMutex::Unlock() {
665   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
666   u32 v = atomic_exchange(m, MtxUnlocked, memory_order_release);
667   CHECK_NE(v, MtxUnlocked);
668   if (v == MtxSleeping) {
669 #if SANITIZER_FREEBSD
670     _umtx_op(m, UMTX_OP_WAKE, 1, 0, 0);
671 #elif SANITIZER_NETBSD
672                    /* No userspace futex-like synchronization */
673 #else
674     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAKE_PRIVATE, 1, 0, 0, 0);
675 #endif
676   }
677 }
678 
679 void BlockingMutex::CheckLocked() {
680   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
681   CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed));
682 }
683 #endif // !SANITIZER_SOLARIS
684 
685 // ----------------- sanitizer_linux.h
686 // The actual size of this structure is specified by d_reclen.
687 // Note that getdents64 uses a different structure format. We only provide the
688 // 32-bit syscall here.
689 #if SANITIZER_NETBSD
690 // Not used
691 #elif SANITIZER_OPENBSD
692 // struct dirent is different for Linux and us. At this moment, we use only
693 // d_fileno (Linux call this d_ino), d_reclen, and d_name.
694 struct linux_dirent {
695   u64 d_ino;  // d_fileno
696   u16 d_reclen;
697   u16 d_namlen;  // not used
698   u8 d_type;     // not used
699   char d_name[NAME_MAX + 1];
700 };
701 #else
702 struct linux_dirent {
703 #if SANITIZER_X32 || defined(__aarch64__)
704   u64 d_ino;
705   u64 d_off;
706 #else
707   unsigned long      d_ino;
708   unsigned long      d_off;
709 #endif
710   unsigned short     d_reclen;
711 #ifdef __aarch64__
712   unsigned char      d_type;
713 #endif
714   char               d_name[256];
715 };
716 #endif
717 
718 #if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
719 // Syscall wrappers.
720 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
721   return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
722                           (uptr)data);
723 }
724 
725 uptr internal_waitpid(int pid, int *status, int options) {
726   return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
727                           0 /* rusage */);
728 }
729 
730 uptr internal_getpid() {
731   return internal_syscall(SYSCALL(getpid));
732 }
733 
734 uptr internal_getppid() {
735   return internal_syscall(SYSCALL(getppid));
736 }
737 
738 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
739 #if SANITIZER_FREEBSD
740   return internal_syscall(SYSCALL(getdirentries), fd, (uptr)dirp, count, NULL);
741 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
742   return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
743 #else
744   return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
745 #endif
746 }
747 
748 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
749   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
750 }
751 
752 #if SANITIZER_LINUX
753 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
754   return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
755 }
756 #endif
757 
758 uptr internal_sigaltstack(const void *ss, void *oss) {
759   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
760 }
761 
762 int internal_fork() {
763 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
764   return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
765 #else
766   return internal_syscall(SYSCALL(fork));
767 #endif
768 }
769 
770 #if SANITIZER_FREEBSD || SANITIZER_OPENBSD
771 int internal_sysctl(const int *name, unsigned int namelen, void *oldp,
772                     uptr *oldlenp, const void *newp, uptr newlen) {
773 #if SANITIZER_OPENBSD
774   return sysctl(name, namelen, oldp, (size_t *)oldlenp, (void *)newp,
775                 (size_t)newlen);
776 #else
777   return internal_syscall(SYSCALL(__sysctl), name, namelen, oldp,
778                           (size_t *)oldlenp, newp, (size_t)newlen);
779 #endif
780 }
781 
782 #if SANITIZER_FREEBSD
783 int internal_sysctlbyname(const char *sname, void *oldp, uptr *oldlenp,
784                           const void *newp, uptr newlen) {
785   static decltype(sysctlbyname) *real = nullptr;
786   if (!real)
787     real = (decltype(sysctlbyname) *)dlsym(RTLD_NEXT, "sysctlbyname");
788   CHECK(real);
789   return real(sname, oldp, (size_t *)oldlenp, newp, (size_t)newlen);
790 }
791 #endif
792 #endif
793 
794 #if SANITIZER_LINUX
795 #define SA_RESTORER 0x04000000
796 // Doesn't set sa_restorer if the caller did not set it, so use with caution
797 //(see below).
798 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
799   __sanitizer_kernel_sigaction_t k_act, k_oldact;
800   internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
801   internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
802   const __sanitizer_sigaction *u_act = (const __sanitizer_sigaction *)act;
803   __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
804   if (u_act) {
805     k_act.handler = u_act->handler;
806     k_act.sigaction = u_act->sigaction;
807     internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
808                     sizeof(__sanitizer_kernel_sigset_t));
809     // Without SA_RESTORER kernel ignores the calls (probably returns EINVAL).
810     k_act.sa_flags = u_act->sa_flags | SA_RESTORER;
811     // FIXME: most often sa_restorer is unset, however the kernel requires it
812     // to point to a valid signal restorer that calls the rt_sigreturn syscall.
813     // If sa_restorer passed to the kernel is NULL, the program may crash upon
814     // signal delivery or fail to unwind the stack in the signal handler.
815     // libc implementation of sigaction() passes its own restorer to
816     // rt_sigaction, so we need to do the same (we'll need to reimplement the
817     // restorers; for x86_64 the restorer address can be obtained from
818     // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
819 #if !SANITIZER_ANDROID || !SANITIZER_MIPS32
820     k_act.sa_restorer = u_act->sa_restorer;
821 #endif
822   }
823 
824   uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
825       (uptr)(u_act ? &k_act : nullptr),
826       (uptr)(u_oldact ? &k_oldact : nullptr),
827       (uptr)sizeof(__sanitizer_kernel_sigset_t));
828 
829   if ((result == 0) && u_oldact) {
830     u_oldact->handler = k_oldact.handler;
831     u_oldact->sigaction = k_oldact.sigaction;
832     internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
833                     sizeof(__sanitizer_kernel_sigset_t));
834     u_oldact->sa_flags = k_oldact.sa_flags;
835 #if !SANITIZER_ANDROID || !SANITIZER_MIPS32
836     u_oldact->sa_restorer = k_oldact.sa_restorer;
837 #endif
838   }
839   return result;
840 }
841 #endif  // SANITIZER_LINUX
842 
843 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
844                           __sanitizer_sigset_t *oldset) {
845 #if SANITIZER_FREEBSD || SANITIZER_OPENBSD
846   return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
847 #else
848   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
849   __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
850   return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how,
851                           (uptr)&k_set->sig[0], (uptr)&k_oldset->sig[0],
852                           sizeof(__sanitizer_kernel_sigset_t));
853 #endif
854 }
855 
856 void internal_sigfillset(__sanitizer_sigset_t *set) {
857   internal_memset(set, 0xff, sizeof(*set));
858 }
859 
860 void internal_sigemptyset(__sanitizer_sigset_t *set) {
861   internal_memset(set, 0, sizeof(*set));
862 }
863 
864 #if SANITIZER_LINUX
865 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
866   signum -= 1;
867   CHECK_GE(signum, 0);
868   CHECK_LT(signum, sizeof(*set) * 8);
869   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
870   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
871   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
872   k_set->sig[idx] &= ~(1 << bit);
873 }
874 
875 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
876   signum -= 1;
877   CHECK_GE(signum, 0);
878   CHECK_LT(signum, sizeof(*set) * 8);
879   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
880   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
881   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
882   return k_set->sig[idx] & (1 << bit);
883 }
884 #elif SANITIZER_FREEBSD
885 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
886   sigset_t *rset = reinterpret_cast<sigset_t *>(set);
887   sigdelset(rset, signum);
888 }
889 
890 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
891   sigset_t *rset = reinterpret_cast<sigset_t *>(set);
892   return sigismember(rset, signum);
893 }
894 #endif
895 #endif // !SANITIZER_SOLARIS
896 
897 #if !SANITIZER_NETBSD
898 // ThreadLister implementation.
899 ThreadLister::ThreadLister(pid_t pid) : pid_(pid), buffer_(4096) {
900   char task_directory_path[80];
901   internal_snprintf(task_directory_path, sizeof(task_directory_path),
902                     "/proc/%d/task/", pid);
903   descriptor_ = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
904   if (internal_iserror(descriptor_)) {
905     Report("Can't open /proc/%d/task for reading.\n", pid);
906   }
907 }
908 
909 ThreadLister::Result ThreadLister::ListThreads(
910     InternalMmapVector<tid_t> *threads) {
911   if (internal_iserror(descriptor_))
912     return Error;
913   internal_lseek(descriptor_, 0, SEEK_SET);
914   threads->clear();
915 
916   Result result = Ok;
917   for (bool first_read = true;; first_read = false) {
918     // Resize to max capacity if it was downsized by IsAlive.
919     buffer_.resize(buffer_.capacity());
920     CHECK_GE(buffer_.size(), 4096);
921     uptr read = internal_getdents(
922         descriptor_, (struct linux_dirent *)buffer_.data(), buffer_.size());
923     if (!read)
924       return result;
925     if (internal_iserror(read)) {
926       Report("Can't read directory entries from /proc/%d/task.\n", pid_);
927       return Error;
928     }
929 
930     for (uptr begin = (uptr)buffer_.data(), end = begin + read; begin < end;) {
931       struct linux_dirent *entry = (struct linux_dirent *)begin;
932       begin += entry->d_reclen;
933       if (entry->d_ino == 1) {
934         // Inode 1 is for bad blocks and also can be a reason for early return.
935         // Should be emitted if kernel tried to output terminating thread.
936         // See proc_task_readdir implementation in Linux.
937         result = Incomplete;
938       }
939       if (entry->d_ino && *entry->d_name >= '0' && *entry->d_name <= '9')
940         threads->push_back(internal_atoll(entry->d_name));
941     }
942 
943     // Now we are going to detect short-read or early EOF. In such cases Linux
944     // can return inconsistent list with missing alive threads.
945     // Code will just remember that the list can be incomplete but it will
946     // continue reads to return as much as possible.
947     if (!first_read) {
948       // The first one was a short-read by definition.
949       result = Incomplete;
950     } else if (read > buffer_.size() - 1024) {
951       // Read was close to the buffer size. So double the size and assume the
952       // worst.
953       buffer_.resize(buffer_.size() * 2);
954       result = Incomplete;
955     } else if (!threads->empty() && !IsAlive(threads->back())) {
956       // Maybe Linux early returned from read on terminated thread (!pid_alive)
957       // and failed to restore read position.
958       // See next_tid and proc_task_instantiate in Linux.
959       result = Incomplete;
960     }
961   }
962 }
963 
964 bool ThreadLister::IsAlive(int tid) {
965   // /proc/%d/task/%d/status uses same call to detect alive threads as
966   // proc_task_readdir. See task_state implementation in Linux.
967   char path[80];
968   internal_snprintf(path, sizeof(path), "/proc/%d/task/%d/status", pid_, tid);
969   if (!ReadFileToVector(path, &buffer_) || buffer_.empty())
970     return false;
971   buffer_.push_back(0);
972   static const char kPrefix[] = "\nPPid:";
973   const char *field = internal_strstr(buffer_.data(), kPrefix);
974   if (!field)
975     return false;
976   field += internal_strlen(kPrefix);
977   return (int)internal_atoll(field) != 0;
978 }
979 
980 ThreadLister::~ThreadLister() {
981   if (!internal_iserror(descriptor_))
982     internal_close(descriptor_);
983 }
984 #endif
985 
986 #if SANITIZER_WORDSIZE == 32
987 // Take care of unusable kernel area in top gigabyte.
988 static uptr GetKernelAreaSize() {
989 #if SANITIZER_LINUX && !SANITIZER_X32
990   const uptr gbyte = 1UL << 30;
991 
992   // Firstly check if there are writable segments
993   // mapped to top gigabyte (e.g. stack).
994   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
995   if (proc_maps.Error())
996     return 0;
997   MemoryMappedSegment segment;
998   while (proc_maps.Next(&segment)) {
999     if ((segment.end >= 3 * gbyte) && segment.IsWritable()) return 0;
1000   }
1001 
1002 #if !SANITIZER_ANDROID
1003   // Even if nothing is mapped, top Gb may still be accessible
1004   // if we are running on 64-bit kernel.
1005   // Uname may report misleading results if personality type
1006   // is modified (e.g. under schroot) so check this as well.
1007   struct utsname uname_info;
1008   int pers = personality(0xffffffffUL);
1009   if (!(pers & PER_MASK)
1010       && uname(&uname_info) == 0
1011       && internal_strstr(uname_info.machine, "64"))
1012     return 0;
1013 #endif  // SANITIZER_ANDROID
1014 
1015   // Top gigabyte is reserved for kernel.
1016   return gbyte;
1017 #else
1018   return 0;
1019 #endif  // SANITIZER_LINUX && !SANITIZER_X32
1020 }
1021 #endif  // SANITIZER_WORDSIZE == 32
1022 
1023 uptr GetMaxVirtualAddress() {
1024 #if (SANITIZER_NETBSD || SANITIZER_OPENBSD) && defined(__x86_64__)
1025   return 0x7f7ffffff000ULL;  // (0x00007f8000000000 - PAGE_SIZE)
1026 #elif SANITIZER_WORDSIZE == 64
1027 # if defined(__powerpc64__) || defined(__aarch64__)
1028   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
1029   // We somehow need to figure out which one we are using now and choose
1030   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
1031   // Note that with 'ulimit -s unlimited' the stack is moved away from the top
1032   // of the address space, so simply checking the stack address is not enough.
1033   // This should (does) work for both PowerPC64 Endian modes.
1034   // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
1035   return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
1036 # elif defined(__mips64)
1037   return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
1038 # elif defined(__s390x__)
1039   return (1ULL << 53) - 1;  // 0x001fffffffffffffUL;
1040 #elif defined(__sparc__)
1041   return ~(uptr)0;
1042 # else
1043   return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
1044 # endif
1045 #else  // SANITIZER_WORDSIZE == 32
1046 # if defined(__s390__)
1047   return (1ULL << 31) - 1;  // 0x7fffffff;
1048 # else
1049   return (1ULL << 32) - 1;  // 0xffffffff;
1050 # endif
1051 #endif  // SANITIZER_WORDSIZE
1052 }
1053 
1054 uptr GetMaxUserVirtualAddress() {
1055   uptr addr = GetMaxVirtualAddress();
1056 #if SANITIZER_WORDSIZE == 32 && !defined(__s390__)
1057   if (!common_flags()->full_address_space)
1058     addr -= GetKernelAreaSize();
1059   CHECK_LT(reinterpret_cast<uptr>(&addr), addr);
1060 #endif
1061   return addr;
1062 }
1063 
1064 #if !SANITIZER_ANDROID
1065 uptr GetPageSize() {
1066 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
1067   return EXEC_PAGESIZE;
1068 #elif SANITIZER_FREEBSD || SANITIZER_NETBSD
1069 // Use sysctl as sysconf can trigger interceptors internally.
1070   int pz = 0;
1071   uptr pzl = sizeof(pz);
1072   int mib[2] = {CTL_HW, HW_PAGESIZE};
1073   int rv = internal_sysctl(mib, 2, &pz, &pzl, nullptr, 0);
1074   CHECK_EQ(rv, 0);
1075   return (uptr)pz;
1076 #elif SANITIZER_USE_GETAUXVAL
1077   return getauxval(AT_PAGESZ);
1078 #else
1079   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
1080 #endif
1081 }
1082 #endif // !SANITIZER_ANDROID
1083 
1084 #if !SANITIZER_OPENBSD
1085 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
1086 #if SANITIZER_SOLARIS
1087   const char *default_module_name = getexecname();
1088   CHECK_NE(default_module_name, NULL);
1089   return internal_snprintf(buf, buf_len, "%s", default_module_name);
1090 #else
1091 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
1092 #if SANITIZER_FREEBSD
1093   const int Mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
1094 #else
1095   const int Mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME};
1096 #endif
1097   const char *default_module_name = "kern.proc.pathname";
1098   uptr Size = buf_len;
1099   bool IsErr =
1100       (internal_sysctl(Mib, ARRAY_SIZE(Mib), buf, &Size, NULL, 0) != 0);
1101   int readlink_error = IsErr ? errno : 0;
1102   uptr module_name_len = Size;
1103 #else
1104   const char *default_module_name = "/proc/self/exe";
1105   uptr module_name_len = internal_readlink(
1106       default_module_name, buf, buf_len);
1107   int readlink_error;
1108   bool IsErr = internal_iserror(module_name_len, &readlink_error);
1109 #endif  // SANITIZER_SOLARIS
1110   if (IsErr) {
1111     // We can't read binary name for some reason, assume it's unknown.
1112     Report("WARNING: reading executable name failed with errno %d, "
1113            "some stack frames may not be symbolized\n", readlink_error);
1114     module_name_len = internal_snprintf(buf, buf_len, "%s",
1115                                         default_module_name);
1116     CHECK_LT(module_name_len, buf_len);
1117   }
1118   return module_name_len;
1119 #endif
1120 }
1121 #endif // !SANITIZER_OPENBSD
1122 
1123 uptr ReadLongProcessName(/*out*/ char *buf, uptr buf_len) {
1124 #if SANITIZER_LINUX
1125   char *tmpbuf;
1126   uptr tmpsize;
1127   uptr tmplen;
1128   if (ReadFileToBuffer("/proc/self/cmdline", &tmpbuf, &tmpsize, &tmplen,
1129                        1024 * 1024)) {
1130     internal_strncpy(buf, tmpbuf, buf_len);
1131     UnmapOrDie(tmpbuf, tmpsize);
1132     return internal_strlen(buf);
1133   }
1134 #endif
1135   return ReadBinaryName(buf, buf_len);
1136 }
1137 
1138 // Match full names of the form /path/to/base_name{-,.}*
1139 bool LibraryNameIs(const char *full_name, const char *base_name) {
1140   const char *name = full_name;
1141   // Strip path.
1142   while (*name != '\0') name++;
1143   while (name > full_name && *name != '/') name--;
1144   if (*name == '/') name++;
1145   uptr base_name_length = internal_strlen(base_name);
1146   if (internal_strncmp(name, base_name, base_name_length)) return false;
1147   return (name[base_name_length] == '-' || name[base_name_length] == '.');
1148 }
1149 
1150 #if !SANITIZER_ANDROID
1151 // Call cb for each region mapped by map.
1152 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
1153   CHECK_NE(map, nullptr);
1154 #if !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
1155   typedef ElfW(Phdr) Elf_Phdr;
1156   typedef ElfW(Ehdr) Elf_Ehdr;
1157 #endif // !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
1158   char *base = (char *)map->l_addr;
1159   Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
1160   char *phdrs = base + ehdr->e_phoff;
1161   char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
1162 
1163   // Find the segment with the minimum base so we can "relocate" the p_vaddr
1164   // fields.  Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
1165   // objects have a non-zero base.
1166   uptr preferred_base = (uptr)-1;
1167   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1168     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1169     if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
1170       preferred_base = (uptr)phdr->p_vaddr;
1171   }
1172 
1173   // Compute the delta from the real base to get a relocation delta.
1174   sptr delta = (uptr)base - preferred_base;
1175   // Now we can figure out what the loader really mapped.
1176   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1177     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1178     if (phdr->p_type == PT_LOAD) {
1179       uptr seg_start = phdr->p_vaddr + delta;
1180       uptr seg_end = seg_start + phdr->p_memsz;
1181       // None of these values are aligned.  We consider the ragged edges of the
1182       // load command as defined, since they are mapped from the file.
1183       seg_start = RoundDownTo(seg_start, GetPageSizeCached());
1184       seg_end = RoundUpTo(seg_end, GetPageSizeCached());
1185       cb((void *)seg_start, seg_end - seg_start);
1186     }
1187   }
1188 }
1189 #endif
1190 
1191 #if defined(__x86_64__) && SANITIZER_LINUX
1192 // We cannot use glibc's clone wrapper, because it messes with the child
1193 // task's TLS. It writes the PID and TID of the child task to its thread
1194 // descriptor, but in our case the child task shares the thread descriptor with
1195 // the parent (because we don't know how to allocate a new thread
1196 // descriptor to keep glibc happy). So the stock version of clone(), when
1197 // used with CLONE_VM, would end up corrupting the parent's thread descriptor.
1198 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1199                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1200   long long res;
1201   if (!fn || !child_stack)
1202     return -EINVAL;
1203   CHECK_EQ(0, (uptr)child_stack % 16);
1204   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1205   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1206   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1207   register void *r8 __asm__("r8") = newtls;
1208   register int *r10 __asm__("r10") = child_tidptr;
1209   __asm__ __volatile__(
1210                        /* %rax = syscall(%rax = SYSCALL(clone),
1211                         *                %rdi = flags,
1212                         *                %rsi = child_stack,
1213                         *                %rdx = parent_tidptr,
1214                         *                %r8  = new_tls,
1215                         *                %r10 = child_tidptr)
1216                         */
1217                        "syscall\n"
1218 
1219                        /* if (%rax != 0)
1220                         *   return;
1221                         */
1222                        "testq  %%rax,%%rax\n"
1223                        "jnz    1f\n"
1224 
1225                        /* In the child. Terminate unwind chain. */
1226                        // XXX: We should also terminate the CFI unwind chain
1227                        // here. Unfortunately clang 3.2 doesn't support the
1228                        // necessary CFI directives, so we skip that part.
1229                        "xorq   %%rbp,%%rbp\n"
1230 
1231                        /* Call "fn(arg)". */
1232                        "popq   %%rax\n"
1233                        "popq   %%rdi\n"
1234                        "call   *%%rax\n"
1235 
1236                        /* Call _exit(%rax). */
1237                        "movq   %%rax,%%rdi\n"
1238                        "movq   %2,%%rax\n"
1239                        "syscall\n"
1240 
1241                        /* Return to parent. */
1242                      "1:\n"
1243                        : "=a" (res)
1244                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1245                          "S"(child_stack),
1246                          "D"(flags),
1247                          "d"(parent_tidptr),
1248                          "r"(r8),
1249                          "r"(r10)
1250                        : "memory", "r11", "rcx");
1251   return res;
1252 }
1253 #elif defined(__mips__)
1254 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1255                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1256   long long res;
1257   if (!fn || !child_stack)
1258     return -EINVAL;
1259   CHECK_EQ(0, (uptr)child_stack % 16);
1260   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1261   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1262   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1263   register void *a3 __asm__("$7") = newtls;
1264   register int *a4 __asm__("$8") = child_tidptr;
1265   // We don't have proper CFI directives here because it requires alot of code
1266   // for very marginal benefits.
1267   __asm__ __volatile__(
1268                        /* $v0 = syscall($v0 = __NR_clone,
1269                         * $a0 = flags,
1270                         * $a1 = child_stack,
1271                         * $a2 = parent_tidptr,
1272                         * $a3 = new_tls,
1273                         * $a4 = child_tidptr)
1274                         */
1275                        ".cprestore 16;\n"
1276                        "move $4,%1;\n"
1277                        "move $5,%2;\n"
1278                        "move $6,%3;\n"
1279                        "move $7,%4;\n"
1280                        /* Store the fifth argument on stack
1281                         * if we are using 32-bit abi.
1282                         */
1283 #if SANITIZER_WORDSIZE == 32
1284                        "lw %5,16($29);\n"
1285 #else
1286                        "move $8,%5;\n"
1287 #endif
1288                        "li $2,%6;\n"
1289                        "syscall;\n"
1290 
1291                        /* if ($v0 != 0)
1292                         * return;
1293                         */
1294                        "bnez $2,1f;\n"
1295 
1296                        /* Call "fn(arg)". */
1297 #if SANITIZER_WORDSIZE == 32
1298 #ifdef __BIG_ENDIAN__
1299                        "lw $25,4($29);\n"
1300                        "lw $4,12($29);\n"
1301 #else
1302                        "lw $25,0($29);\n"
1303                        "lw $4,8($29);\n"
1304 #endif
1305 #else
1306                        "ld $25,0($29);\n"
1307                        "ld $4,8($29);\n"
1308 #endif
1309                        "jal $25;\n"
1310 
1311                        /* Call _exit($v0). */
1312                        "move $4,$2;\n"
1313                        "li $2,%7;\n"
1314                        "syscall;\n"
1315 
1316                        /* Return to parent. */
1317                      "1:\n"
1318                        : "=r" (res)
1319                        : "r"(flags),
1320                          "r"(child_stack),
1321                          "r"(parent_tidptr),
1322                          "r"(a3),
1323                          "r"(a4),
1324                          "i"(__NR_clone),
1325                          "i"(__NR_exit)
1326                        : "memory", "$29" );
1327   return res;
1328 }
1329 #elif defined(__aarch64__)
1330 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1331                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1332   long long res;
1333   if (!fn || !child_stack)
1334     return -EINVAL;
1335   CHECK_EQ(0, (uptr)child_stack % 16);
1336   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1337   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1338   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1339 
1340   register int (*__fn)(void *)  __asm__("x0") = fn;
1341   register void *__stack __asm__("x1") = child_stack;
1342   register int   __flags __asm__("x2") = flags;
1343   register void *__arg   __asm__("x3") = arg;
1344   register int  *__ptid  __asm__("x4") = parent_tidptr;
1345   register void *__tls   __asm__("x5") = newtls;
1346   register int  *__ctid  __asm__("x6") = child_tidptr;
1347 
1348   __asm__ __volatile__(
1349                        "mov x0,x2\n" /* flags  */
1350                        "mov x2,x4\n" /* ptid  */
1351                        "mov x3,x5\n" /* tls  */
1352                        "mov x4,x6\n" /* ctid  */
1353                        "mov x8,%9\n" /* clone  */
1354 
1355                        "svc 0x0\n"
1356 
1357                        /* if (%r0 != 0)
1358                         *   return %r0;
1359                         */
1360                        "cmp x0, #0\n"
1361                        "bne 1f\n"
1362 
1363                        /* In the child, now. Call "fn(arg)". */
1364                        "ldp x1, x0, [sp], #16\n"
1365                        "blr x1\n"
1366 
1367                        /* Call _exit(%r0).  */
1368                        "mov x8, %10\n"
1369                        "svc 0x0\n"
1370                      "1:\n"
1371 
1372                        : "=r" (res)
1373                        : "i"(-EINVAL),
1374                          "r"(__fn), "r"(__stack), "r"(__flags), "r"(__arg),
1375                          "r"(__ptid), "r"(__tls), "r"(__ctid),
1376                          "i"(__NR_clone), "i"(__NR_exit)
1377                        : "x30", "memory");
1378   return res;
1379 }
1380 #elif defined(__powerpc64__)
1381 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1382                    int *parent_tidptr, void *newtls, int *child_tidptr) {
1383   long long res;
1384 // Stack frame structure.
1385 #if SANITIZER_PPC64V1
1386 //   Back chain == 0        (SP + 112)
1387 // Frame (112 bytes):
1388 //   Parameter save area    (SP + 48), 8 doublewords
1389 //   TOC save area          (SP + 40)
1390 //   Link editor doubleword (SP + 32)
1391 //   Compiler doubleword    (SP + 24)
1392 //   LR save area           (SP + 16)
1393 //   CR save area           (SP + 8)
1394 //   Back chain             (SP + 0)
1395 # define FRAME_SIZE 112
1396 # define FRAME_TOC_SAVE_OFFSET 40
1397 #elif SANITIZER_PPC64V2
1398 //   Back chain == 0        (SP + 32)
1399 // Frame (32 bytes):
1400 //   TOC save area          (SP + 24)
1401 //   LR save area           (SP + 16)
1402 //   CR save area           (SP + 8)
1403 //   Back chain             (SP + 0)
1404 # define FRAME_SIZE 32
1405 # define FRAME_TOC_SAVE_OFFSET 24
1406 #else
1407 # error "Unsupported PPC64 ABI"
1408 #endif
1409   if (!fn || !child_stack)
1410     return -EINVAL;
1411   CHECK_EQ(0, (uptr)child_stack % 16);
1412 
1413   register int (*__fn)(void *) __asm__("r3") = fn;
1414   register void *__cstack      __asm__("r4") = child_stack;
1415   register int __flags         __asm__("r5") = flags;
1416   register void *__arg         __asm__("r6") = arg;
1417   register int *__ptidptr      __asm__("r7") = parent_tidptr;
1418   register void *__newtls      __asm__("r8") = newtls;
1419   register int *__ctidptr      __asm__("r9") = child_tidptr;
1420 
1421  __asm__ __volatile__(
1422            /* fn and arg are saved across the syscall */
1423            "mr 28, %5\n\t"
1424            "mr 27, %8\n\t"
1425 
1426            /* syscall
1427              r0 == __NR_clone
1428              r3 == flags
1429              r4 == child_stack
1430              r5 == parent_tidptr
1431              r6 == newtls
1432              r7 == child_tidptr */
1433            "mr 3, %7\n\t"
1434            "mr 5, %9\n\t"
1435            "mr 6, %10\n\t"
1436            "mr 7, %11\n\t"
1437            "li 0, %3\n\t"
1438            "sc\n\t"
1439 
1440            /* Test if syscall was successful */
1441            "cmpdi  cr1, 3, 0\n\t"
1442            "crandc cr1*4+eq, cr1*4+eq, cr0*4+so\n\t"
1443            "bne-   cr1, 1f\n\t"
1444 
1445            /* Set up stack frame */
1446            "li    29, 0\n\t"
1447            "stdu  29, -8(1)\n\t"
1448            "stdu  1, -%12(1)\n\t"
1449            /* Do the function call */
1450            "std   2, %13(1)\n\t"
1451 #if SANITIZER_PPC64V1
1452            "ld    0, 0(28)\n\t"
1453            "ld    2, 8(28)\n\t"
1454            "mtctr 0\n\t"
1455 #elif SANITIZER_PPC64V2
1456            "mr    12, 28\n\t"
1457            "mtctr 12\n\t"
1458 #else
1459 # error "Unsupported PPC64 ABI"
1460 #endif
1461            "mr    3, 27\n\t"
1462            "bctrl\n\t"
1463            "ld    2, %13(1)\n\t"
1464 
1465            /* Call _exit(r3) */
1466            "li 0, %4\n\t"
1467            "sc\n\t"
1468 
1469            /* Return to parent */
1470            "1:\n\t"
1471            "mr %0, 3\n\t"
1472              : "=r" (res)
1473              : "0" (-1),
1474                "i" (EINVAL),
1475                "i" (__NR_clone),
1476                "i" (__NR_exit),
1477                "r" (__fn),
1478                "r" (__cstack),
1479                "r" (__flags),
1480                "r" (__arg),
1481                "r" (__ptidptr),
1482                "r" (__newtls),
1483                "r" (__ctidptr),
1484                "i" (FRAME_SIZE),
1485                "i" (FRAME_TOC_SAVE_OFFSET)
1486              : "cr0", "cr1", "memory", "ctr", "r0", "r27", "r28", "r29");
1487   return res;
1488 }
1489 #elif defined(__i386__) && SANITIZER_LINUX
1490 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1491                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1492   int res;
1493   if (!fn || !child_stack)
1494     return -EINVAL;
1495   CHECK_EQ(0, (uptr)child_stack % 16);
1496   child_stack = (char *)child_stack - 7 * sizeof(unsigned int);
1497   ((unsigned int *)child_stack)[0] = (uptr)flags;
1498   ((unsigned int *)child_stack)[1] = (uptr)0;
1499   ((unsigned int *)child_stack)[2] = (uptr)fn;
1500   ((unsigned int *)child_stack)[3] = (uptr)arg;
1501   __asm__ __volatile__(
1502                        /* %eax = syscall(%eax = SYSCALL(clone),
1503                         *                %ebx = flags,
1504                         *                %ecx = child_stack,
1505                         *                %edx = parent_tidptr,
1506                         *                %esi  = new_tls,
1507                         *                %edi = child_tidptr)
1508                         */
1509 
1510                         /* Obtain flags */
1511                         "movl    (%%ecx), %%ebx\n"
1512                         /* Do the system call */
1513                         "pushl   %%ebx\n"
1514                         "pushl   %%esi\n"
1515                         "pushl   %%edi\n"
1516                         /* Remember the flag value.  */
1517                         "movl    %%ebx, (%%ecx)\n"
1518                         "int     $0x80\n"
1519                         "popl    %%edi\n"
1520                         "popl    %%esi\n"
1521                         "popl    %%ebx\n"
1522 
1523                         /* if (%eax != 0)
1524                          *   return;
1525                          */
1526 
1527                         "test    %%eax,%%eax\n"
1528                         "jnz    1f\n"
1529 
1530                         /* terminate the stack frame */
1531                         "xorl   %%ebp,%%ebp\n"
1532                         /* Call FN. */
1533                         "call    *%%ebx\n"
1534 #ifdef PIC
1535                         "call    here\n"
1536                         "here:\n"
1537                         "popl    %%ebx\n"
1538                         "addl    $_GLOBAL_OFFSET_TABLE_+[.-here], %%ebx\n"
1539 #endif
1540                         /* Call exit */
1541                         "movl    %%eax, %%ebx\n"
1542                         "movl    %2, %%eax\n"
1543                         "int     $0x80\n"
1544                         "1:\n"
1545                        : "=a" (res)
1546                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1547                          "c"(child_stack),
1548                          "d"(parent_tidptr),
1549                          "S"(newtls),
1550                          "D"(child_tidptr)
1551                        : "memory");
1552   return res;
1553 }
1554 #elif defined(__arm__) && SANITIZER_LINUX
1555 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1556                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1557   unsigned int res;
1558   if (!fn || !child_stack)
1559     return -EINVAL;
1560   child_stack = (char *)child_stack - 2 * sizeof(unsigned int);
1561   ((unsigned int *)child_stack)[0] = (uptr)fn;
1562   ((unsigned int *)child_stack)[1] = (uptr)arg;
1563   register int r0 __asm__("r0") = flags;
1564   register void *r1 __asm__("r1") = child_stack;
1565   register int *r2 __asm__("r2") = parent_tidptr;
1566   register void *r3 __asm__("r3") = newtls;
1567   register int *r4 __asm__("r4") = child_tidptr;
1568   register int r7 __asm__("r7") = __NR_clone;
1569 
1570 #if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
1571 # define ARCH_HAS_BX
1572 #endif
1573 #if __ARM_ARCH > 4
1574 # define ARCH_HAS_BLX
1575 #endif
1576 
1577 #ifdef ARCH_HAS_BX
1578 # ifdef ARCH_HAS_BLX
1579 #  define BLX(R) "blx "  #R "\n"
1580 # else
1581 #  define BLX(R) "mov lr, pc; bx " #R "\n"
1582 # endif
1583 #else
1584 # define BLX(R)  "mov lr, pc; mov pc," #R "\n"
1585 #endif
1586 
1587   __asm__ __volatile__(
1588                        /* %r0 = syscall(%r7 = SYSCALL(clone),
1589                         *               %r0 = flags,
1590                         *               %r1 = child_stack,
1591                         *               %r2 = parent_tidptr,
1592                         *               %r3  = new_tls,
1593                         *               %r4 = child_tidptr)
1594                         */
1595 
1596                        /* Do the system call */
1597                        "swi 0x0\n"
1598 
1599                        /* if (%r0 != 0)
1600                         *   return %r0;
1601                         */
1602                        "cmp r0, #0\n"
1603                        "bne 1f\n"
1604 
1605                        /* In the child, now. Call "fn(arg)". */
1606                        "ldr r0, [sp, #4]\n"
1607                        "ldr ip, [sp], #8\n"
1608                        BLX(ip)
1609                        /* Call _exit(%r0). */
1610                        "mov r7, %7\n"
1611                        "swi 0x0\n"
1612                        "1:\n"
1613                        "mov %0, r0\n"
1614                        : "=r"(res)
1615                        : "r"(r0), "r"(r1), "r"(r2), "r"(r3), "r"(r4), "r"(r7),
1616                          "i"(__NR_exit)
1617                        : "memory");
1618   return res;
1619 }
1620 #endif  // defined(__x86_64__) && SANITIZER_LINUX
1621 
1622 #if SANITIZER_ANDROID
1623 #if __ANDROID_API__ < 21
1624 extern "C" __attribute__((weak)) int dl_iterate_phdr(
1625     int (*)(struct dl_phdr_info *, size_t, void *), void *);
1626 #endif
1627 
1628 static int dl_iterate_phdr_test_cb(struct dl_phdr_info *info, size_t size,
1629                                    void *data) {
1630   // Any name starting with "lib" indicates a bug in L where library base names
1631   // are returned instead of paths.
1632   if (info->dlpi_name && info->dlpi_name[0] == 'l' &&
1633       info->dlpi_name[1] == 'i' && info->dlpi_name[2] == 'b') {
1634     *(bool *)data = true;
1635     return 1;
1636   }
1637   return 0;
1638 }
1639 
1640 static atomic_uint32_t android_api_level;
1641 
1642 static AndroidApiLevel AndroidDetectApiLevelStatic() {
1643 #if __ANDROID_API__ <= 19
1644   return ANDROID_KITKAT;
1645 #elif __ANDROID_API__ <= 22
1646   return ANDROID_LOLLIPOP_MR1;
1647 #else
1648   return ANDROID_POST_LOLLIPOP;
1649 #endif
1650 }
1651 
1652 static AndroidApiLevel AndroidDetectApiLevel() {
1653   if (!&dl_iterate_phdr)
1654     return ANDROID_KITKAT; // K or lower
1655   bool base_name_seen = false;
1656   dl_iterate_phdr(dl_iterate_phdr_test_cb, &base_name_seen);
1657   if (base_name_seen)
1658     return ANDROID_LOLLIPOP_MR1; // L MR1
1659   return ANDROID_POST_LOLLIPOP;   // post-L
1660   // Plain L (API level 21) is completely broken wrt ASan and not very
1661   // interesting to detect.
1662 }
1663 
1664 extern "C" __attribute__((weak)) void* _DYNAMIC;
1665 
1666 AndroidApiLevel AndroidGetApiLevel() {
1667   AndroidApiLevel level =
1668       (AndroidApiLevel)atomic_load(&android_api_level, memory_order_relaxed);
1669   if (level) return level;
1670   level = &_DYNAMIC == nullptr ? AndroidDetectApiLevelStatic()
1671                                : AndroidDetectApiLevel();
1672   atomic_store(&android_api_level, level, memory_order_relaxed);
1673   return level;
1674 }
1675 
1676 #endif
1677 
1678 static HandleSignalMode GetHandleSignalModeImpl(int signum) {
1679   switch (signum) {
1680     case SIGABRT:
1681       return common_flags()->handle_abort;
1682     case SIGILL:
1683       return common_flags()->handle_sigill;
1684     case SIGTRAP:
1685       return common_flags()->handle_sigtrap;
1686     case SIGFPE:
1687       return common_flags()->handle_sigfpe;
1688     case SIGSEGV:
1689       return common_flags()->handle_segv;
1690     case SIGBUS:
1691       return common_flags()->handle_sigbus;
1692   }
1693   return kHandleSignalNo;
1694 }
1695 
1696 HandleSignalMode GetHandleSignalMode(int signum) {
1697   HandleSignalMode result = GetHandleSignalModeImpl(signum);
1698   if (result == kHandleSignalYes && !common_flags()->allow_user_segv_handler)
1699     return kHandleSignalExclusive;
1700   return result;
1701 }
1702 
1703 #if !SANITIZER_GO
1704 void *internal_start_thread(void(*func)(void *arg), void *arg) {
1705   // Start the thread with signals blocked, otherwise it can steal user signals.
1706   __sanitizer_sigset_t set, old;
1707   internal_sigfillset(&set);
1708 #if SANITIZER_LINUX && !SANITIZER_ANDROID
1709   // Glibc uses SIGSETXID signal during setuid call. If this signal is blocked
1710   // on any thread, setuid call hangs (see test/tsan/setuid.c).
1711   internal_sigdelset(&set, 33);
1712 #endif
1713   internal_sigprocmask(SIG_SETMASK, &set, &old);
1714   void *th;
1715   real_pthread_create(&th, nullptr, (void*(*)(void *arg))func, arg);
1716   internal_sigprocmask(SIG_SETMASK, &old, nullptr);
1717   return th;
1718 }
1719 
1720 void internal_join_thread(void *th) {
1721   real_pthread_join(th, nullptr);
1722 }
1723 #else
1724 void *internal_start_thread(void (*func)(void *), void *arg) { return 0; }
1725 
1726 void internal_join_thread(void *th) {}
1727 #endif
1728 
1729 #if defined(__aarch64__)
1730 // Android headers in the older NDK releases miss this definition.
1731 struct __sanitizer_esr_context {
1732   struct _aarch64_ctx head;
1733   uint64_t esr;
1734 };
1735 
1736 static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
1737   static const u32 kEsrMagic = 0x45535201;
1738   u8 *aux = ucontext->uc_mcontext.__reserved;
1739   while (true) {
1740     _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
1741     if (ctx->size == 0) break;
1742     if (ctx->magic == kEsrMagic) {
1743       *esr = ((__sanitizer_esr_context *)ctx)->esr;
1744       return true;
1745     }
1746     aux += ctx->size;
1747   }
1748   return false;
1749 }
1750 #endif
1751 
1752 #if SANITIZER_OPENBSD
1753 using Context = sigcontext;
1754 #else
1755 using Context = ucontext_t;
1756 #endif
1757 
1758 SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
1759   Context *ucontext = (Context *)context;
1760 #if defined(__x86_64__) || defined(__i386__)
1761   static const uptr PF_WRITE = 1U << 1;
1762 #if SANITIZER_FREEBSD
1763   uptr err = ucontext->uc_mcontext.mc_err;
1764 #elif SANITIZER_NETBSD
1765   uptr err = ucontext->uc_mcontext.__gregs[_REG_ERR];
1766 #elif SANITIZER_OPENBSD
1767   uptr err = ucontext->sc_err;
1768 #elif SANITIZER_SOLARIS && defined(__i386__)
1769   const int Err = 13;
1770   uptr err = ucontext->uc_mcontext.gregs[Err];
1771 #else
1772   uptr err = ucontext->uc_mcontext.gregs[REG_ERR];
1773 #endif // SANITIZER_FREEBSD
1774   return err & PF_WRITE ? WRITE : READ;
1775 #elif defined(__mips__)
1776   uint32_t *exception_source;
1777   uint32_t faulty_instruction;
1778   uint32_t op_code;
1779 
1780   exception_source = (uint32_t *)ucontext->uc_mcontext.pc;
1781   faulty_instruction = (uint32_t)(*exception_source);
1782 
1783   op_code = (faulty_instruction >> 26) & 0x3f;
1784 
1785   // FIXME: Add support for FPU, microMIPS, DSP, MSA memory instructions.
1786   switch (op_code) {
1787     case 0x28:  // sb
1788     case 0x29:  // sh
1789     case 0x2b:  // sw
1790     case 0x3f:  // sd
1791 #if __mips_isa_rev < 6
1792     case 0x2c:  // sdl
1793     case 0x2d:  // sdr
1794     case 0x2a:  // swl
1795     case 0x2e:  // swr
1796 #endif
1797       return SignalContext::WRITE;
1798 
1799     case 0x20:  // lb
1800     case 0x24:  // lbu
1801     case 0x21:  // lh
1802     case 0x25:  // lhu
1803     case 0x23:  // lw
1804     case 0x27:  // lwu
1805     case 0x37:  // ld
1806 #if __mips_isa_rev < 6
1807     case 0x1a:  // ldl
1808     case 0x1b:  // ldr
1809     case 0x22:  // lwl
1810     case 0x26:  // lwr
1811 #endif
1812       return SignalContext::READ;
1813 #if __mips_isa_rev == 6
1814     case 0x3b:  // pcrel
1815       op_code = (faulty_instruction >> 19) & 0x3;
1816       switch (op_code) {
1817         case 0x1:  // lwpc
1818         case 0x2:  // lwupc
1819           return SignalContext::READ;
1820       }
1821 #endif
1822   }
1823   return SignalContext::UNKNOWN;
1824 #elif defined(__arm__)
1825   static const uptr FSR_WRITE = 1U << 11;
1826   uptr fsr = ucontext->uc_mcontext.error_code;
1827   return fsr & FSR_WRITE ? WRITE : READ;
1828 #elif defined(__aarch64__)
1829   static const u64 ESR_ELx_WNR = 1U << 6;
1830   u64 esr;
1831   if (!Aarch64GetESR(ucontext, &esr)) return UNKNOWN;
1832   return esr & ESR_ELx_WNR ? WRITE : READ;
1833 #elif defined(__sparc__)
1834   // Decode the instruction to determine the access type.
1835   // From OpenSolaris $SRC/uts/sun4/os/trap.c (get_accesstype).
1836 #if SANITIZER_SOLARIS
1837   uptr pc = ucontext->uc_mcontext.gregs[REG_PC];
1838 #else
1839   // Historical BSDism here.
1840   struct sigcontext *scontext = (struct sigcontext *)context;
1841 #if defined(__arch64__)
1842   uptr pc = scontext->sigc_regs.tpc;
1843 #else
1844   uptr pc = scontext->si_regs.pc;
1845 #endif
1846 #endif
1847   u32 instr = *(u32 *)pc;
1848   return (instr >> 21) & 1 ? WRITE: READ;
1849 #else
1850   (void)ucontext;
1851   return UNKNOWN;  // FIXME: Implement.
1852 #endif
1853 }
1854 
1855 bool SignalContext::IsTrueFaultingAddress() const {
1856   auto si = static_cast<const siginfo_t *>(siginfo);
1857   // SIGSEGV signals without a true fault address have si_code set to 128.
1858   return si->si_signo == SIGSEGV && si->si_code != 128;
1859 }
1860 
1861 void SignalContext::DumpAllRegisters(void *context) {
1862   // FIXME: Implement this.
1863 }
1864 
1865 static void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
1866 #if SANITIZER_NETBSD
1867   // This covers all NetBSD architectures
1868   ucontext_t *ucontext = (ucontext_t *)context;
1869   *pc = _UC_MACHINE_PC(ucontext);
1870   *bp = _UC_MACHINE_FP(ucontext);
1871   *sp = _UC_MACHINE_SP(ucontext);
1872 #elif defined(__arm__)
1873   ucontext_t *ucontext = (ucontext_t*)context;
1874   *pc = ucontext->uc_mcontext.arm_pc;
1875   *bp = ucontext->uc_mcontext.arm_fp;
1876   *sp = ucontext->uc_mcontext.arm_sp;
1877 #elif defined(__aarch64__)
1878   ucontext_t *ucontext = (ucontext_t*)context;
1879   *pc = ucontext->uc_mcontext.pc;
1880   *bp = ucontext->uc_mcontext.regs[29];
1881   *sp = ucontext->uc_mcontext.sp;
1882 #elif defined(__hppa__)
1883   ucontext_t *ucontext = (ucontext_t*)context;
1884   *pc = ucontext->uc_mcontext.sc_iaoq[0];
1885   /* GCC uses %r3 whenever a frame pointer is needed.  */
1886   *bp = ucontext->uc_mcontext.sc_gr[3];
1887   *sp = ucontext->uc_mcontext.sc_gr[30];
1888 #elif defined(__x86_64__)
1889 # if SANITIZER_FREEBSD
1890   ucontext_t *ucontext = (ucontext_t*)context;
1891   *pc = ucontext->uc_mcontext.mc_rip;
1892   *bp = ucontext->uc_mcontext.mc_rbp;
1893   *sp = ucontext->uc_mcontext.mc_rsp;
1894 #elif SANITIZER_OPENBSD
1895   sigcontext *ucontext = (sigcontext *)context;
1896   *pc = ucontext->sc_rip;
1897   *bp = ucontext->sc_rbp;
1898   *sp = ucontext->sc_rsp;
1899 # else
1900   ucontext_t *ucontext = (ucontext_t*)context;
1901   *pc = ucontext->uc_mcontext.gregs[REG_RIP];
1902   *bp = ucontext->uc_mcontext.gregs[REG_RBP];
1903   *sp = ucontext->uc_mcontext.gregs[REG_RSP];
1904 # endif
1905 #elif defined(__i386__)
1906 # if SANITIZER_FREEBSD
1907   ucontext_t *ucontext = (ucontext_t*)context;
1908   *pc = ucontext->uc_mcontext.mc_eip;
1909   *bp = ucontext->uc_mcontext.mc_ebp;
1910   *sp = ucontext->uc_mcontext.mc_esp;
1911 #elif SANITIZER_OPENBSD
1912   sigcontext *ucontext = (sigcontext *)context;
1913   *pc = ucontext->sc_eip;
1914   *bp = ucontext->sc_ebp;
1915   *sp = ucontext->sc_esp;
1916 # else
1917   ucontext_t *ucontext = (ucontext_t*)context;
1918 # if SANITIZER_SOLARIS
1919   /* Use the numeric values: the symbolic ones are undefined by llvm
1920      include/llvm/Support/Solaris.h.  */
1921 # ifndef REG_EIP
1922 #  define REG_EIP 14 // REG_PC
1923 # endif
1924 # ifndef REG_EBP
1925 #  define REG_EBP  6 // REG_FP
1926 # endif
1927 # ifndef REG_ESP
1928 #  define REG_ESP 17 // REG_SP
1929 # endif
1930 # endif
1931   *pc = ucontext->uc_mcontext.gregs[REG_EIP];
1932   *bp = ucontext->uc_mcontext.gregs[REG_EBP];
1933   *sp = ucontext->uc_mcontext.gregs[REG_ESP];
1934 # endif
1935 #elif defined(__powerpc__) || defined(__powerpc64__)
1936   ucontext_t *ucontext = (ucontext_t*)context;
1937   *pc = ucontext->uc_mcontext.regs->nip;
1938   *sp = ucontext->uc_mcontext.regs->gpr[PT_R1];
1939   // The powerpc{,64}-linux ABIs do not specify r31 as the frame
1940   // pointer, but GCC always uses r31 when we need a frame pointer.
1941   *bp = ucontext->uc_mcontext.regs->gpr[PT_R31];
1942 #elif defined(__sparc__)
1943 #if defined(__arch64__) || defined(__sparcv9)
1944 #define STACK_BIAS 2047
1945 #else
1946 #define STACK_BIAS 0
1947 # endif
1948 # if SANITIZER_SOLARIS
1949   ucontext_t *ucontext = (ucontext_t *)context;
1950   *pc = ucontext->uc_mcontext.gregs[REG_PC];
1951   *sp = ucontext->uc_mcontext.gregs[REG_O6] + STACK_BIAS;
1952 #else
1953   // Historical BSDism here.
1954   struct sigcontext *scontext = (struct sigcontext *)context;
1955 #if defined(__arch64__)
1956   *pc = scontext->sigc_regs.tpc;
1957   *sp = scontext->sigc_regs.u_regs[14] + STACK_BIAS;
1958 #else
1959   *pc = scontext->si_regs.pc;
1960   *sp = scontext->si_regs.u_regs[14];
1961 #endif
1962 # endif
1963   *bp = (uptr)((uhwptr *)*sp)[14] + STACK_BIAS;
1964 #elif defined(__mips__)
1965   ucontext_t *ucontext = (ucontext_t*)context;
1966   *pc = ucontext->uc_mcontext.pc;
1967   *bp = ucontext->uc_mcontext.gregs[30];
1968   *sp = ucontext->uc_mcontext.gregs[29];
1969 #elif defined(__s390__)
1970   ucontext_t *ucontext = (ucontext_t*)context;
1971 # if defined(__s390x__)
1972   *pc = ucontext->uc_mcontext.psw.addr;
1973 # else
1974   *pc = ucontext->uc_mcontext.psw.addr & 0x7fffffff;
1975 # endif
1976   *bp = ucontext->uc_mcontext.gregs[11];
1977   *sp = ucontext->uc_mcontext.gregs[15];
1978 #elif defined(__riscv)
1979   ucontext_t *ucontext = (ucontext_t*)context;
1980   *pc = ucontext->uc_mcontext.__gregs[REG_PC];
1981   *bp = ucontext->uc_mcontext.__gregs[REG_S0];
1982   *sp = ucontext->uc_mcontext.__gregs[REG_SP];
1983 #else
1984 # error "Unsupported arch"
1985 #endif
1986 }
1987 
1988 void SignalContext::InitPcSpBp() { GetPcSpBp(context, &pc, &sp, &bp); }
1989 
1990 void InitializePlatformEarly() {
1991   // Do nothing.
1992 }
1993 
1994 void MaybeReexec() {
1995   // No need to re-exec on Linux.
1996 }
1997 
1998 void CheckASLR() {
1999 #if SANITIZER_NETBSD
2000   int mib[3];
2001   int paxflags;
2002   uptr len = sizeof(paxflags);
2003 
2004   mib[0] = CTL_PROC;
2005   mib[1] = internal_getpid();
2006   mib[2] = PROC_PID_PAXFLAGS;
2007 
2008   if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2009     Printf("sysctl failed\n");
2010     Die();
2011   }
2012 
2013   if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_ASLR)) {
2014     Printf("This sanitizer is not compatible with enabled ASLR\n");
2015     Die();
2016   }
2017 #elif SANITIZER_PPC64V2
2018   // Disable ASLR for Linux PPC64LE.
2019   int old_personality = personality(0xffffffff);
2020   if (old_personality != -1 && (old_personality & ADDR_NO_RANDOMIZE) == 0) {
2021     VReport(1, "WARNING: Program is being run with address space layout "
2022                "randomization (ASLR) enabled which prevents the thread and "
2023                "memory sanitizers from working on powerpc64le.\n"
2024                "ASLR will be disabled and the program re-executed.\n");
2025     CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
2026     ReExec();
2027   }
2028 #elif SANITIZER_FREEBSD
2029   int aslr_pie;
2030   uptr len = sizeof(aslr_pie);
2031 #if SANITIZER_WORDSIZE == 64
2032   if (UNLIKELY(internal_sysctlbyname("kern.elf64.aslr.pie_enable",
2033       &aslr_pie, &len, NULL, 0) == -1)) {
2034     // We're making things less 'dramatic' here since
2035     // the OID is not necessarily guaranteed to be here
2036     // just yet regarding FreeBSD release
2037     return;
2038   }
2039 
2040   if (aslr_pie > 0) {
2041     Printf("This sanitizer is not compatible with enabled ASLR "
2042            "and binaries compiled with PIE\n");
2043     Die();
2044   }
2045 #endif
2046   // there might be 32 bits compat for 64 bits
2047   if (UNLIKELY(internal_sysctlbyname("kern.elf32.aslr.pie_enable",
2048       &aslr_pie, &len, NULL, 0) == -1)) {
2049     return;
2050   }
2051 
2052   if (aslr_pie > 0) {
2053     Printf("This sanitizer is not compatible with enabled ASLR "
2054            "and binaries compiled with PIE\n");
2055     Die();
2056   }
2057 #else
2058   // Do nothing
2059 #endif
2060 }
2061 
2062 void CheckMPROTECT() {
2063 #if SANITIZER_NETBSD
2064   int mib[3];
2065   int paxflags;
2066   uptr len = sizeof(paxflags);
2067 
2068   mib[0] = CTL_PROC;
2069   mib[1] = internal_getpid();
2070   mib[2] = PROC_PID_PAXFLAGS;
2071 
2072   if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2073     Printf("sysctl failed\n");
2074     Die();
2075   }
2076 
2077   if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_MPROTECT)) {
2078     Printf("This sanitizer is not compatible with enabled MPROTECT\n");
2079     Die();
2080   }
2081 #else
2082   // Do nothing
2083 #endif
2084 }
2085 
2086 void PrintModuleMap() { }
2087 
2088 void CheckNoDeepBind(const char *filename, int flag) {
2089 #ifdef RTLD_DEEPBIND
2090   if (flag & RTLD_DEEPBIND) {
2091     Report(
2092         "You are trying to dlopen a %s shared library with RTLD_DEEPBIND flag"
2093         " which is incompatibe with sanitizer runtime "
2094         "(see https://github.com/google/sanitizers/issues/611 for details"
2095         "). If you want to run %s library under sanitizers please remove "
2096         "RTLD_DEEPBIND from dlopen flags.\n",
2097         filename, filename);
2098     Die();
2099   }
2100 #endif
2101 }
2102 
2103 uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
2104                               uptr *largest_gap_found,
2105                               uptr *max_occupied_addr) {
2106   UNREACHABLE("FindAvailableMemoryRange is not available");
2107   return 0;
2108 }
2109 
2110 bool GetRandom(void *buffer, uptr length, bool blocking) {
2111   if (!buffer || !length || length > 256)
2112     return false;
2113 #if SANITIZER_USE_GETENTROPY
2114   uptr rnd = getentropy(buffer, length);
2115   int rverrno = 0;
2116   if (internal_iserror(rnd, &rverrno) && rverrno == EFAULT)
2117     return false;
2118   else if (rnd == 0)
2119     return true;
2120 #endif // SANITIZER_USE_GETENTROPY
2121 
2122 #if SANITIZER_USE_GETRANDOM
2123   static atomic_uint8_t skip_getrandom_syscall;
2124   if (!atomic_load_relaxed(&skip_getrandom_syscall)) {
2125     // Up to 256 bytes, getrandom will not be interrupted.
2126     uptr res = internal_syscall(SYSCALL(getrandom), buffer, length,
2127                                 blocking ? 0 : GRND_NONBLOCK);
2128     int rverrno = 0;
2129     if (internal_iserror(res, &rverrno) && rverrno == ENOSYS)
2130       atomic_store_relaxed(&skip_getrandom_syscall, 1);
2131     else if (res == length)
2132       return true;
2133   }
2134 #endif // SANITIZER_USE_GETRANDOM
2135   // Up to 256 bytes, a read off /dev/urandom will not be interrupted.
2136   // blocking is moot here, O_NONBLOCK has no effect when opening /dev/urandom.
2137   uptr fd = internal_open("/dev/urandom", O_RDONLY);
2138   if (internal_iserror(fd))
2139     return false;
2140   uptr res = internal_read(fd, buffer, length);
2141   if (internal_iserror(res))
2142     return false;
2143   internal_close(fd);
2144   return true;
2145 }
2146 
2147 } // namespace __sanitizer
2148 
2149 #endif
2150