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 int internal_dlinfo(void *handle, int request, void *p) {
739 #if SANITIZER_FREEBSD
740   return dlinfo(handle, request, p);
741 #else
742   UNIMPLEMENTED();
743 #endif
744 }
745 
746 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
747 #if SANITIZER_FREEBSD
748   return internal_syscall(SYSCALL(getdirentries), fd, (uptr)dirp, count, NULL);
749 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
750   return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
751 #else
752   return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
753 #endif
754 }
755 
756 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
757   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
758 }
759 
760 #if SANITIZER_LINUX
761 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
762   return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
763 }
764 #endif
765 
766 uptr internal_sigaltstack(const void *ss, void *oss) {
767   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
768 }
769 
770 int internal_fork() {
771 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
772   return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
773 #else
774   return internal_syscall(SYSCALL(fork));
775 #endif
776 }
777 
778 #if SANITIZER_FREEBSD || SANITIZER_OPENBSD
779 int internal_sysctl(const int *name, unsigned int namelen, void *oldp,
780                     uptr *oldlenp, const void *newp, uptr newlen) {
781 #if SANITIZER_OPENBSD
782   return sysctl(name, namelen, oldp, (size_t *)oldlenp, (void *)newp,
783                 (size_t)newlen);
784 #else
785   return internal_syscall(SYSCALL(__sysctl), name, namelen, oldp,
786                           (size_t *)oldlenp, newp, (size_t)newlen);
787 #endif
788 }
789 
790 #if SANITIZER_FREEBSD
791 int internal_sysctlbyname(const char *sname, void *oldp, uptr *oldlenp,
792                           const void *newp, uptr newlen) {
793   static decltype(sysctlbyname) *real = nullptr;
794   if (!real)
795     real = (decltype(sysctlbyname) *)dlsym(RTLD_NEXT, "sysctlbyname");
796   CHECK(real);
797   return real(sname, oldp, (size_t *)oldlenp, newp, (size_t)newlen);
798 }
799 #endif
800 #endif
801 
802 #if SANITIZER_LINUX
803 #define SA_RESTORER 0x04000000
804 // Doesn't set sa_restorer if the caller did not set it, so use with caution
805 //(see below).
806 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
807   __sanitizer_kernel_sigaction_t k_act, k_oldact;
808   internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
809   internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
810   const __sanitizer_sigaction *u_act = (const __sanitizer_sigaction *)act;
811   __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
812   if (u_act) {
813     k_act.handler = u_act->handler;
814     k_act.sigaction = u_act->sigaction;
815     internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
816                     sizeof(__sanitizer_kernel_sigset_t));
817     // Without SA_RESTORER kernel ignores the calls (probably returns EINVAL).
818     k_act.sa_flags = u_act->sa_flags | SA_RESTORER;
819     // FIXME: most often sa_restorer is unset, however the kernel requires it
820     // to point to a valid signal restorer that calls the rt_sigreturn syscall.
821     // If sa_restorer passed to the kernel is NULL, the program may crash upon
822     // signal delivery or fail to unwind the stack in the signal handler.
823     // libc implementation of sigaction() passes its own restorer to
824     // rt_sigaction, so we need to do the same (we'll need to reimplement the
825     // restorers; for x86_64 the restorer address can be obtained from
826     // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
827 #if !SANITIZER_ANDROID || !SANITIZER_MIPS32
828     k_act.sa_restorer = u_act->sa_restorer;
829 #endif
830   }
831 
832   uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
833       (uptr)(u_act ? &k_act : nullptr),
834       (uptr)(u_oldact ? &k_oldact : nullptr),
835       (uptr)sizeof(__sanitizer_kernel_sigset_t));
836 
837   if ((result == 0) && u_oldact) {
838     u_oldact->handler = k_oldact.handler;
839     u_oldact->sigaction = k_oldact.sigaction;
840     internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
841                     sizeof(__sanitizer_kernel_sigset_t));
842     u_oldact->sa_flags = k_oldact.sa_flags;
843 #if !SANITIZER_ANDROID || !SANITIZER_MIPS32
844     u_oldact->sa_restorer = k_oldact.sa_restorer;
845 #endif
846   }
847   return result;
848 }
849 #endif  // SANITIZER_LINUX
850 
851 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
852                           __sanitizer_sigset_t *oldset) {
853 #if SANITIZER_FREEBSD || SANITIZER_OPENBSD
854   return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
855 #else
856   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
857   __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
858   return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how,
859                           (uptr)&k_set->sig[0], (uptr)&k_oldset->sig[0],
860                           sizeof(__sanitizer_kernel_sigset_t));
861 #endif
862 }
863 
864 void internal_sigfillset(__sanitizer_sigset_t *set) {
865   internal_memset(set, 0xff, sizeof(*set));
866 }
867 
868 void internal_sigemptyset(__sanitizer_sigset_t *set) {
869   internal_memset(set, 0, sizeof(*set));
870 }
871 
872 #if SANITIZER_LINUX
873 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
874   signum -= 1;
875   CHECK_GE(signum, 0);
876   CHECK_LT(signum, sizeof(*set) * 8);
877   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
878   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
879   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
880   k_set->sig[idx] &= ~(1 << bit);
881 }
882 
883 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
884   signum -= 1;
885   CHECK_GE(signum, 0);
886   CHECK_LT(signum, sizeof(*set) * 8);
887   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
888   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
889   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
890   return k_set->sig[idx] & (1 << bit);
891 }
892 #elif SANITIZER_FREEBSD
893 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
894   sigset_t *rset = reinterpret_cast<sigset_t *>(set);
895   sigdelset(rset, signum);
896 }
897 
898 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
899   sigset_t *rset = reinterpret_cast<sigset_t *>(set);
900   return sigismember(rset, signum);
901 }
902 #endif
903 #endif // !SANITIZER_SOLARIS
904 
905 #if !SANITIZER_NETBSD
906 // ThreadLister implementation.
907 ThreadLister::ThreadLister(pid_t pid) : pid_(pid), buffer_(4096) {
908   char task_directory_path[80];
909   internal_snprintf(task_directory_path, sizeof(task_directory_path),
910                     "/proc/%d/task/", pid);
911   descriptor_ = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
912   if (internal_iserror(descriptor_)) {
913     Report("Can't open /proc/%d/task for reading.\n", pid);
914   }
915 }
916 
917 ThreadLister::Result ThreadLister::ListThreads(
918     InternalMmapVector<tid_t> *threads) {
919   if (internal_iserror(descriptor_))
920     return Error;
921   internal_lseek(descriptor_, 0, SEEK_SET);
922   threads->clear();
923 
924   Result result = Ok;
925   for (bool first_read = true;; first_read = false) {
926     // Resize to max capacity if it was downsized by IsAlive.
927     buffer_.resize(buffer_.capacity());
928     CHECK_GE(buffer_.size(), 4096);
929     uptr read = internal_getdents(
930         descriptor_, (struct linux_dirent *)buffer_.data(), buffer_.size());
931     if (!read)
932       return result;
933     if (internal_iserror(read)) {
934       Report("Can't read directory entries from /proc/%d/task.\n", pid_);
935       return Error;
936     }
937 
938     for (uptr begin = (uptr)buffer_.data(), end = begin + read; begin < end;) {
939       struct linux_dirent *entry = (struct linux_dirent *)begin;
940       begin += entry->d_reclen;
941       if (entry->d_ino == 1) {
942         // Inode 1 is for bad blocks and also can be a reason for early return.
943         // Should be emitted if kernel tried to output terminating thread.
944         // See proc_task_readdir implementation in Linux.
945         result = Incomplete;
946       }
947       if (entry->d_ino && *entry->d_name >= '0' && *entry->d_name <= '9')
948         threads->push_back(internal_atoll(entry->d_name));
949     }
950 
951     // Now we are going to detect short-read or early EOF. In such cases Linux
952     // can return inconsistent list with missing alive threads.
953     // Code will just remember that the list can be incomplete but it will
954     // continue reads to return as much as possible.
955     if (!first_read) {
956       // The first one was a short-read by definition.
957       result = Incomplete;
958     } else if (read > buffer_.size() - 1024) {
959       // Read was close to the buffer size. So double the size and assume the
960       // worst.
961       buffer_.resize(buffer_.size() * 2);
962       result = Incomplete;
963     } else if (!threads->empty() && !IsAlive(threads->back())) {
964       // Maybe Linux early returned from read on terminated thread (!pid_alive)
965       // and failed to restore read position.
966       // See next_tid and proc_task_instantiate in Linux.
967       result = Incomplete;
968     }
969   }
970 }
971 
972 bool ThreadLister::IsAlive(int tid) {
973   // /proc/%d/task/%d/status uses same call to detect alive threads as
974   // proc_task_readdir. See task_state implementation in Linux.
975   char path[80];
976   internal_snprintf(path, sizeof(path), "/proc/%d/task/%d/status", pid_, tid);
977   if (!ReadFileToVector(path, &buffer_) || buffer_.empty())
978     return false;
979   buffer_.push_back(0);
980   static const char kPrefix[] = "\nPPid:";
981   const char *field = internal_strstr(buffer_.data(), kPrefix);
982   if (!field)
983     return false;
984   field += internal_strlen(kPrefix);
985   return (int)internal_atoll(field) != 0;
986 }
987 
988 ThreadLister::~ThreadLister() {
989   if (!internal_iserror(descriptor_))
990     internal_close(descriptor_);
991 }
992 #endif
993 
994 #if SANITIZER_WORDSIZE == 32
995 // Take care of unusable kernel area in top gigabyte.
996 static uptr GetKernelAreaSize() {
997 #if SANITIZER_LINUX && !SANITIZER_X32
998   const uptr gbyte = 1UL << 30;
999 
1000   // Firstly check if there are writable segments
1001   // mapped to top gigabyte (e.g. stack).
1002   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
1003   if (proc_maps.Error())
1004     return 0;
1005   MemoryMappedSegment segment;
1006   while (proc_maps.Next(&segment)) {
1007     if ((segment.end >= 3 * gbyte) && segment.IsWritable()) return 0;
1008   }
1009 
1010 #if !SANITIZER_ANDROID
1011   // Even if nothing is mapped, top Gb may still be accessible
1012   // if we are running on 64-bit kernel.
1013   // Uname may report misleading results if personality type
1014   // is modified (e.g. under schroot) so check this as well.
1015   struct utsname uname_info;
1016   int pers = personality(0xffffffffUL);
1017   if (!(pers & PER_MASK)
1018       && uname(&uname_info) == 0
1019       && internal_strstr(uname_info.machine, "64"))
1020     return 0;
1021 #endif  // SANITIZER_ANDROID
1022 
1023   // Top gigabyte is reserved for kernel.
1024   return gbyte;
1025 #else
1026   return 0;
1027 #endif  // SANITIZER_LINUX && !SANITIZER_X32
1028 }
1029 #endif  // SANITIZER_WORDSIZE == 32
1030 
1031 uptr GetMaxVirtualAddress() {
1032 #if (SANITIZER_NETBSD || SANITIZER_OPENBSD) && defined(__x86_64__)
1033   return 0x7f7ffffff000ULL;  // (0x00007f8000000000 - PAGE_SIZE)
1034 #elif SANITIZER_WORDSIZE == 64
1035 # if defined(__powerpc64__) || defined(__aarch64__)
1036   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
1037   // We somehow need to figure out which one we are using now and choose
1038   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
1039   // Note that with 'ulimit -s unlimited' the stack is moved away from the top
1040   // of the address space, so simply checking the stack address is not enough.
1041   // This should (does) work for both PowerPC64 Endian modes.
1042   // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
1043   return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
1044 # elif defined(__mips64)
1045   return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
1046 # elif defined(__s390x__)
1047   return (1ULL << 53) - 1;  // 0x001fffffffffffffUL;
1048 #elif defined(__sparc__)
1049   return ~(uptr)0;
1050 # else
1051   return (1ULL << 47) - 1;  // 0x00007fffffffffffUL;
1052 # endif
1053 #else  // SANITIZER_WORDSIZE == 32
1054 # if defined(__s390__)
1055   return (1ULL << 31) - 1;  // 0x7fffffff;
1056 # else
1057   return (1ULL << 32) - 1;  // 0xffffffff;
1058 # endif
1059 #endif  // SANITIZER_WORDSIZE
1060 }
1061 
1062 uptr GetMaxUserVirtualAddress() {
1063   uptr addr = GetMaxVirtualAddress();
1064 #if SANITIZER_WORDSIZE == 32 && !defined(__s390__)
1065   if (!common_flags()->full_address_space)
1066     addr -= GetKernelAreaSize();
1067   CHECK_LT(reinterpret_cast<uptr>(&addr), addr);
1068 #endif
1069   return addr;
1070 }
1071 
1072 #if !SANITIZER_ANDROID
1073 uptr GetPageSize() {
1074 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
1075   return EXEC_PAGESIZE;
1076 #elif SANITIZER_FREEBSD || SANITIZER_NETBSD
1077 // Use sysctl as sysconf can trigger interceptors internally.
1078   int pz = 0;
1079   uptr pzl = sizeof(pz);
1080   int mib[2] = {CTL_HW, HW_PAGESIZE};
1081   int rv = internal_sysctl(mib, 2, &pz, &pzl, nullptr, 0);
1082   CHECK_EQ(rv, 0);
1083   return (uptr)pz;
1084 #elif SANITIZER_USE_GETAUXVAL
1085   return getauxval(AT_PAGESZ);
1086 #else
1087   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
1088 #endif
1089 }
1090 #endif // !SANITIZER_ANDROID
1091 
1092 #if !SANITIZER_OPENBSD
1093 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
1094 #if SANITIZER_SOLARIS
1095   const char *default_module_name = getexecname();
1096   CHECK_NE(default_module_name, NULL);
1097   return internal_snprintf(buf, buf_len, "%s", default_module_name);
1098 #else
1099 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
1100 #if SANITIZER_FREEBSD
1101   const int Mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
1102 #else
1103   const int Mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME};
1104 #endif
1105   const char *default_module_name = "kern.proc.pathname";
1106   uptr Size = buf_len;
1107   bool IsErr =
1108       (internal_sysctl(Mib, ARRAY_SIZE(Mib), buf, &Size, NULL, 0) != 0);
1109   int readlink_error = IsErr ? errno : 0;
1110   uptr module_name_len = Size;
1111 #else
1112   const char *default_module_name = "/proc/self/exe";
1113   uptr module_name_len = internal_readlink(
1114       default_module_name, buf, buf_len);
1115   int readlink_error;
1116   bool IsErr = internal_iserror(module_name_len, &readlink_error);
1117 #endif  // SANITIZER_SOLARIS
1118   if (IsErr) {
1119     // We can't read binary name for some reason, assume it's unknown.
1120     Report("WARNING: reading executable name failed with errno %d, "
1121            "some stack frames may not be symbolized\n", readlink_error);
1122     module_name_len = internal_snprintf(buf, buf_len, "%s",
1123                                         default_module_name);
1124     CHECK_LT(module_name_len, buf_len);
1125   }
1126   return module_name_len;
1127 #endif
1128 }
1129 #endif // !SANITIZER_OPENBSD
1130 
1131 uptr ReadLongProcessName(/*out*/ char *buf, uptr buf_len) {
1132 #if SANITIZER_LINUX
1133   char *tmpbuf;
1134   uptr tmpsize;
1135   uptr tmplen;
1136   if (ReadFileToBuffer("/proc/self/cmdline", &tmpbuf, &tmpsize, &tmplen,
1137                        1024 * 1024)) {
1138     internal_strncpy(buf, tmpbuf, buf_len);
1139     UnmapOrDie(tmpbuf, tmpsize);
1140     return internal_strlen(buf);
1141   }
1142 #endif
1143   return ReadBinaryName(buf, buf_len);
1144 }
1145 
1146 // Match full names of the form /path/to/base_name{-,.}*
1147 bool LibraryNameIs(const char *full_name, const char *base_name) {
1148   const char *name = full_name;
1149   // Strip path.
1150   while (*name != '\0') name++;
1151   while (name > full_name && *name != '/') name--;
1152   if (*name == '/') name++;
1153   uptr base_name_length = internal_strlen(base_name);
1154   if (internal_strncmp(name, base_name, base_name_length)) return false;
1155   return (name[base_name_length] == '-' || name[base_name_length] == '.');
1156 }
1157 
1158 #if !SANITIZER_ANDROID
1159 // Call cb for each region mapped by map.
1160 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
1161   CHECK_NE(map, nullptr);
1162 #if !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
1163   typedef ElfW(Phdr) Elf_Phdr;
1164   typedef ElfW(Ehdr) Elf_Ehdr;
1165 #endif // !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
1166   char *base = (char *)map->l_addr;
1167   Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
1168   char *phdrs = base + ehdr->e_phoff;
1169   char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
1170 
1171   // Find the segment with the minimum base so we can "relocate" the p_vaddr
1172   // fields.  Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
1173   // objects have a non-zero base.
1174   uptr preferred_base = (uptr)-1;
1175   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1176     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1177     if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
1178       preferred_base = (uptr)phdr->p_vaddr;
1179   }
1180 
1181   // Compute the delta from the real base to get a relocation delta.
1182   sptr delta = (uptr)base - preferred_base;
1183   // Now we can figure out what the loader really mapped.
1184   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1185     Elf_Phdr *phdr = (Elf_Phdr *)iter;
1186     if (phdr->p_type == PT_LOAD) {
1187       uptr seg_start = phdr->p_vaddr + delta;
1188       uptr seg_end = seg_start + phdr->p_memsz;
1189       // None of these values are aligned.  We consider the ragged edges of the
1190       // load command as defined, since they are mapped from the file.
1191       seg_start = RoundDownTo(seg_start, GetPageSizeCached());
1192       seg_end = RoundUpTo(seg_end, GetPageSizeCached());
1193       cb((void *)seg_start, seg_end - seg_start);
1194     }
1195   }
1196 }
1197 #endif
1198 
1199 #if defined(__x86_64__) && SANITIZER_LINUX
1200 // We cannot use glibc's clone wrapper, because it messes with the child
1201 // task's TLS. It writes the PID and TID of the child task to its thread
1202 // descriptor, but in our case the child task shares the thread descriptor with
1203 // the parent (because we don't know how to allocate a new thread
1204 // descriptor to keep glibc happy). So the stock version of clone(), when
1205 // used with CLONE_VM, would end up corrupting the parent's thread descriptor.
1206 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1207                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1208   long long res;
1209   if (!fn || !child_stack)
1210     return -EINVAL;
1211   CHECK_EQ(0, (uptr)child_stack % 16);
1212   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1213   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1214   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1215   register void *r8 __asm__("r8") = newtls;
1216   register int *r10 __asm__("r10") = child_tidptr;
1217   __asm__ __volatile__(
1218                        /* %rax = syscall(%rax = SYSCALL(clone),
1219                         *                %rdi = flags,
1220                         *                %rsi = child_stack,
1221                         *                %rdx = parent_tidptr,
1222                         *                %r8  = new_tls,
1223                         *                %r10 = child_tidptr)
1224                         */
1225                        "syscall\n"
1226 
1227                        /* if (%rax != 0)
1228                         *   return;
1229                         */
1230                        "testq  %%rax,%%rax\n"
1231                        "jnz    1f\n"
1232 
1233                        /* In the child. Terminate unwind chain. */
1234                        // XXX: We should also terminate the CFI unwind chain
1235                        // here. Unfortunately clang 3.2 doesn't support the
1236                        // necessary CFI directives, so we skip that part.
1237                        "xorq   %%rbp,%%rbp\n"
1238 
1239                        /* Call "fn(arg)". */
1240                        "popq   %%rax\n"
1241                        "popq   %%rdi\n"
1242                        "call   *%%rax\n"
1243 
1244                        /* Call _exit(%rax). */
1245                        "movq   %%rax,%%rdi\n"
1246                        "movq   %2,%%rax\n"
1247                        "syscall\n"
1248 
1249                        /* Return to parent. */
1250                      "1:\n"
1251                        : "=a" (res)
1252                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1253                          "S"(child_stack),
1254                          "D"(flags),
1255                          "d"(parent_tidptr),
1256                          "r"(r8),
1257                          "r"(r10)
1258                        : "memory", "r11", "rcx");
1259   return res;
1260 }
1261 #elif defined(__mips__)
1262 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1263                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1264   long long res;
1265   if (!fn || !child_stack)
1266     return -EINVAL;
1267   CHECK_EQ(0, (uptr)child_stack % 16);
1268   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1269   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1270   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1271   register void *a3 __asm__("$7") = newtls;
1272   register int *a4 __asm__("$8") = child_tidptr;
1273   // We don't have proper CFI directives here because it requires alot of code
1274   // for very marginal benefits.
1275   __asm__ __volatile__(
1276                        /* $v0 = syscall($v0 = __NR_clone,
1277                         * $a0 = flags,
1278                         * $a1 = child_stack,
1279                         * $a2 = parent_tidptr,
1280                         * $a3 = new_tls,
1281                         * $a4 = child_tidptr)
1282                         */
1283                        ".cprestore 16;\n"
1284                        "move $4,%1;\n"
1285                        "move $5,%2;\n"
1286                        "move $6,%3;\n"
1287                        "move $7,%4;\n"
1288                        /* Store the fifth argument on stack
1289                         * if we are using 32-bit abi.
1290                         */
1291 #if SANITIZER_WORDSIZE == 32
1292                        "lw %5,16($29);\n"
1293 #else
1294                        "move $8,%5;\n"
1295 #endif
1296                        "li $2,%6;\n"
1297                        "syscall;\n"
1298 
1299                        /* if ($v0 != 0)
1300                         * return;
1301                         */
1302                        "bnez $2,1f;\n"
1303 
1304                        /* Call "fn(arg)". */
1305 #if SANITIZER_WORDSIZE == 32
1306 #ifdef __BIG_ENDIAN__
1307                        "lw $25,4($29);\n"
1308                        "lw $4,12($29);\n"
1309 #else
1310                        "lw $25,0($29);\n"
1311                        "lw $4,8($29);\n"
1312 #endif
1313 #else
1314                        "ld $25,0($29);\n"
1315                        "ld $4,8($29);\n"
1316 #endif
1317                        "jal $25;\n"
1318 
1319                        /* Call _exit($v0). */
1320                        "move $4,$2;\n"
1321                        "li $2,%7;\n"
1322                        "syscall;\n"
1323 
1324                        /* Return to parent. */
1325                      "1:\n"
1326                        : "=r" (res)
1327                        : "r"(flags),
1328                          "r"(child_stack),
1329                          "r"(parent_tidptr),
1330                          "r"(a3),
1331                          "r"(a4),
1332                          "i"(__NR_clone),
1333                          "i"(__NR_exit)
1334                        : "memory", "$29" );
1335   return res;
1336 }
1337 #elif defined(__aarch64__)
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 
1348   register int (*__fn)(void *)  __asm__("x0") = fn;
1349   register void *__stack __asm__("x1") = child_stack;
1350   register int   __flags __asm__("x2") = flags;
1351   register void *__arg   __asm__("x3") = arg;
1352   register int  *__ptid  __asm__("x4") = parent_tidptr;
1353   register void *__tls   __asm__("x5") = newtls;
1354   register int  *__ctid  __asm__("x6") = child_tidptr;
1355 
1356   __asm__ __volatile__(
1357                        "mov x0,x2\n" /* flags  */
1358                        "mov x2,x4\n" /* ptid  */
1359                        "mov x3,x5\n" /* tls  */
1360                        "mov x4,x6\n" /* ctid  */
1361                        "mov x8,%9\n" /* clone  */
1362 
1363                        "svc 0x0\n"
1364 
1365                        /* if (%r0 != 0)
1366                         *   return %r0;
1367                         */
1368                        "cmp x0, #0\n"
1369                        "bne 1f\n"
1370 
1371                        /* In the child, now. Call "fn(arg)". */
1372                        "ldp x1, x0, [sp], #16\n"
1373                        "blr x1\n"
1374 
1375                        /* Call _exit(%r0).  */
1376                        "mov x8, %10\n"
1377                        "svc 0x0\n"
1378                      "1:\n"
1379 
1380                        : "=r" (res)
1381                        : "i"(-EINVAL),
1382                          "r"(__fn), "r"(__stack), "r"(__flags), "r"(__arg),
1383                          "r"(__ptid), "r"(__tls), "r"(__ctid),
1384                          "i"(__NR_clone), "i"(__NR_exit)
1385                        : "x30", "memory");
1386   return res;
1387 }
1388 #elif defined(__powerpc64__)
1389 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1390                    int *parent_tidptr, void *newtls, int *child_tidptr) {
1391   long long res;
1392 // Stack frame structure.
1393 #if SANITIZER_PPC64V1
1394 //   Back chain == 0        (SP + 112)
1395 // Frame (112 bytes):
1396 //   Parameter save area    (SP + 48), 8 doublewords
1397 //   TOC save area          (SP + 40)
1398 //   Link editor doubleword (SP + 32)
1399 //   Compiler doubleword    (SP + 24)
1400 //   LR save area           (SP + 16)
1401 //   CR save area           (SP + 8)
1402 //   Back chain             (SP + 0)
1403 # define FRAME_SIZE 112
1404 # define FRAME_TOC_SAVE_OFFSET 40
1405 #elif SANITIZER_PPC64V2
1406 //   Back chain == 0        (SP + 32)
1407 // Frame (32 bytes):
1408 //   TOC save area          (SP + 24)
1409 //   LR save area           (SP + 16)
1410 //   CR save area           (SP + 8)
1411 //   Back chain             (SP + 0)
1412 # define FRAME_SIZE 32
1413 # define FRAME_TOC_SAVE_OFFSET 24
1414 #else
1415 # error "Unsupported PPC64 ABI"
1416 #endif
1417   if (!fn || !child_stack)
1418     return -EINVAL;
1419   CHECK_EQ(0, (uptr)child_stack % 16);
1420 
1421   register int (*__fn)(void *) __asm__("r3") = fn;
1422   register void *__cstack      __asm__("r4") = child_stack;
1423   register int __flags         __asm__("r5") = flags;
1424   register void *__arg         __asm__("r6") = arg;
1425   register int *__ptidptr      __asm__("r7") = parent_tidptr;
1426   register void *__newtls      __asm__("r8") = newtls;
1427   register int *__ctidptr      __asm__("r9") = child_tidptr;
1428 
1429  __asm__ __volatile__(
1430            /* fn and arg are saved across the syscall */
1431            "mr 28, %5\n\t"
1432            "mr 27, %8\n\t"
1433 
1434            /* syscall
1435              r0 == __NR_clone
1436              r3 == flags
1437              r4 == child_stack
1438              r5 == parent_tidptr
1439              r6 == newtls
1440              r7 == child_tidptr */
1441            "mr 3, %7\n\t"
1442            "mr 5, %9\n\t"
1443            "mr 6, %10\n\t"
1444            "mr 7, %11\n\t"
1445            "li 0, %3\n\t"
1446            "sc\n\t"
1447 
1448            /* Test if syscall was successful */
1449            "cmpdi  cr1, 3, 0\n\t"
1450            "crandc cr1*4+eq, cr1*4+eq, cr0*4+so\n\t"
1451            "bne-   cr1, 1f\n\t"
1452 
1453            /* Set up stack frame */
1454            "li    29, 0\n\t"
1455            "stdu  29, -8(1)\n\t"
1456            "stdu  1, -%12(1)\n\t"
1457            /* Do the function call */
1458            "std   2, %13(1)\n\t"
1459 #if SANITIZER_PPC64V1
1460            "ld    0, 0(28)\n\t"
1461            "ld    2, 8(28)\n\t"
1462            "mtctr 0\n\t"
1463 #elif SANITIZER_PPC64V2
1464            "mr    12, 28\n\t"
1465            "mtctr 12\n\t"
1466 #else
1467 # error "Unsupported PPC64 ABI"
1468 #endif
1469            "mr    3, 27\n\t"
1470            "bctrl\n\t"
1471            "ld    2, %13(1)\n\t"
1472 
1473            /* Call _exit(r3) */
1474            "li 0, %4\n\t"
1475            "sc\n\t"
1476 
1477            /* Return to parent */
1478            "1:\n\t"
1479            "mr %0, 3\n\t"
1480              : "=r" (res)
1481              : "0" (-1),
1482                "i" (EINVAL),
1483                "i" (__NR_clone),
1484                "i" (__NR_exit),
1485                "r" (__fn),
1486                "r" (__cstack),
1487                "r" (__flags),
1488                "r" (__arg),
1489                "r" (__ptidptr),
1490                "r" (__newtls),
1491                "r" (__ctidptr),
1492                "i" (FRAME_SIZE),
1493                "i" (FRAME_TOC_SAVE_OFFSET)
1494              : "cr0", "cr1", "memory", "ctr", "r0", "r27", "r28", "r29");
1495   return res;
1496 }
1497 #elif defined(__i386__) && SANITIZER_LINUX
1498 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1499                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1500   int res;
1501   if (!fn || !child_stack)
1502     return -EINVAL;
1503   CHECK_EQ(0, (uptr)child_stack % 16);
1504   child_stack = (char *)child_stack - 7 * sizeof(unsigned int);
1505   ((unsigned int *)child_stack)[0] = (uptr)flags;
1506   ((unsigned int *)child_stack)[1] = (uptr)0;
1507   ((unsigned int *)child_stack)[2] = (uptr)fn;
1508   ((unsigned int *)child_stack)[3] = (uptr)arg;
1509   __asm__ __volatile__(
1510                        /* %eax = syscall(%eax = SYSCALL(clone),
1511                         *                %ebx = flags,
1512                         *                %ecx = child_stack,
1513                         *                %edx = parent_tidptr,
1514                         *                %esi  = new_tls,
1515                         *                %edi = child_tidptr)
1516                         */
1517 
1518                         /* Obtain flags */
1519                         "movl    (%%ecx), %%ebx\n"
1520                         /* Do the system call */
1521                         "pushl   %%ebx\n"
1522                         "pushl   %%esi\n"
1523                         "pushl   %%edi\n"
1524                         /* Remember the flag value.  */
1525                         "movl    %%ebx, (%%ecx)\n"
1526                         "int     $0x80\n"
1527                         "popl    %%edi\n"
1528                         "popl    %%esi\n"
1529                         "popl    %%ebx\n"
1530 
1531                         /* if (%eax != 0)
1532                          *   return;
1533                          */
1534 
1535                         "test    %%eax,%%eax\n"
1536                         "jnz    1f\n"
1537 
1538                         /* terminate the stack frame */
1539                         "xorl   %%ebp,%%ebp\n"
1540                         /* Call FN. */
1541                         "call    *%%ebx\n"
1542 #ifdef PIC
1543                         "call    here\n"
1544                         "here:\n"
1545                         "popl    %%ebx\n"
1546                         "addl    $_GLOBAL_OFFSET_TABLE_+[.-here], %%ebx\n"
1547 #endif
1548                         /* Call exit */
1549                         "movl    %%eax, %%ebx\n"
1550                         "movl    %2, %%eax\n"
1551                         "int     $0x80\n"
1552                         "1:\n"
1553                        : "=a" (res)
1554                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1555                          "c"(child_stack),
1556                          "d"(parent_tidptr),
1557                          "S"(newtls),
1558                          "D"(child_tidptr)
1559                        : "memory");
1560   return res;
1561 }
1562 #elif defined(__arm__) && SANITIZER_LINUX
1563 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1564                     int *parent_tidptr, void *newtls, int *child_tidptr) {
1565   unsigned int res;
1566   if (!fn || !child_stack)
1567     return -EINVAL;
1568   child_stack = (char *)child_stack - 2 * sizeof(unsigned int);
1569   ((unsigned int *)child_stack)[0] = (uptr)fn;
1570   ((unsigned int *)child_stack)[1] = (uptr)arg;
1571   register int r0 __asm__("r0") = flags;
1572   register void *r1 __asm__("r1") = child_stack;
1573   register int *r2 __asm__("r2") = parent_tidptr;
1574   register void *r3 __asm__("r3") = newtls;
1575   register int *r4 __asm__("r4") = child_tidptr;
1576   register int r7 __asm__("r7") = __NR_clone;
1577 
1578 #if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
1579 # define ARCH_HAS_BX
1580 #endif
1581 #if __ARM_ARCH > 4
1582 # define ARCH_HAS_BLX
1583 #endif
1584 
1585 #ifdef ARCH_HAS_BX
1586 # ifdef ARCH_HAS_BLX
1587 #  define BLX(R) "blx "  #R "\n"
1588 # else
1589 #  define BLX(R) "mov lr, pc; bx " #R "\n"
1590 # endif
1591 #else
1592 # define BLX(R)  "mov lr, pc; mov pc," #R "\n"
1593 #endif
1594 
1595   __asm__ __volatile__(
1596                        /* %r0 = syscall(%r7 = SYSCALL(clone),
1597                         *               %r0 = flags,
1598                         *               %r1 = child_stack,
1599                         *               %r2 = parent_tidptr,
1600                         *               %r3  = new_tls,
1601                         *               %r4 = child_tidptr)
1602                         */
1603 
1604                        /* Do the system call */
1605                        "swi 0x0\n"
1606 
1607                        /* if (%r0 != 0)
1608                         *   return %r0;
1609                         */
1610                        "cmp r0, #0\n"
1611                        "bne 1f\n"
1612 
1613                        /* In the child, now. Call "fn(arg)". */
1614                        "ldr r0, [sp, #4]\n"
1615                        "ldr ip, [sp], #8\n"
1616                        BLX(ip)
1617                        /* Call _exit(%r0). */
1618                        "mov r7, %7\n"
1619                        "swi 0x0\n"
1620                        "1:\n"
1621                        "mov %0, r0\n"
1622                        : "=r"(res)
1623                        : "r"(r0), "r"(r1), "r"(r2), "r"(r3), "r"(r4), "r"(r7),
1624                          "i"(__NR_exit)
1625                        : "memory");
1626   return res;
1627 }
1628 #endif  // defined(__x86_64__) && SANITIZER_LINUX
1629 
1630 #if SANITIZER_ANDROID
1631 #if __ANDROID_API__ < 21
1632 extern "C" __attribute__((weak)) int dl_iterate_phdr(
1633     int (*)(struct dl_phdr_info *, size_t, void *), void *);
1634 #endif
1635 
1636 static int dl_iterate_phdr_test_cb(struct dl_phdr_info *info, size_t size,
1637                                    void *data) {
1638   // Any name starting with "lib" indicates a bug in L where library base names
1639   // are returned instead of paths.
1640   if (info->dlpi_name && info->dlpi_name[0] == 'l' &&
1641       info->dlpi_name[1] == 'i' && info->dlpi_name[2] == 'b') {
1642     *(bool *)data = true;
1643     return 1;
1644   }
1645   return 0;
1646 }
1647 
1648 static atomic_uint32_t android_api_level;
1649 
1650 static AndroidApiLevel AndroidDetectApiLevelStatic() {
1651 #if __ANDROID_API__ <= 19
1652   return ANDROID_KITKAT;
1653 #elif __ANDROID_API__ <= 22
1654   return ANDROID_LOLLIPOP_MR1;
1655 #else
1656   return ANDROID_POST_LOLLIPOP;
1657 #endif
1658 }
1659 
1660 static AndroidApiLevel AndroidDetectApiLevel() {
1661   if (!&dl_iterate_phdr)
1662     return ANDROID_KITKAT; // K or lower
1663   bool base_name_seen = false;
1664   dl_iterate_phdr(dl_iterate_phdr_test_cb, &base_name_seen);
1665   if (base_name_seen)
1666     return ANDROID_LOLLIPOP_MR1; // L MR1
1667   return ANDROID_POST_LOLLIPOP;   // post-L
1668   // Plain L (API level 21) is completely broken wrt ASan and not very
1669   // interesting to detect.
1670 }
1671 
1672 extern "C" __attribute__((weak)) void* _DYNAMIC;
1673 
1674 AndroidApiLevel AndroidGetApiLevel() {
1675   AndroidApiLevel level =
1676       (AndroidApiLevel)atomic_load(&android_api_level, memory_order_relaxed);
1677   if (level) return level;
1678   level = &_DYNAMIC == nullptr ? AndroidDetectApiLevelStatic()
1679                                : AndroidDetectApiLevel();
1680   atomic_store(&android_api_level, level, memory_order_relaxed);
1681   return level;
1682 }
1683 
1684 #endif
1685 
1686 static HandleSignalMode GetHandleSignalModeImpl(int signum) {
1687   switch (signum) {
1688     case SIGABRT:
1689       return common_flags()->handle_abort;
1690     case SIGILL:
1691       return common_flags()->handle_sigill;
1692     case SIGTRAP:
1693       return common_flags()->handle_sigtrap;
1694     case SIGFPE:
1695       return common_flags()->handle_sigfpe;
1696     case SIGSEGV:
1697       return common_flags()->handle_segv;
1698     case SIGBUS:
1699       return common_flags()->handle_sigbus;
1700   }
1701   return kHandleSignalNo;
1702 }
1703 
1704 HandleSignalMode GetHandleSignalMode(int signum) {
1705   HandleSignalMode result = GetHandleSignalModeImpl(signum);
1706   if (result == kHandleSignalYes && !common_flags()->allow_user_segv_handler)
1707     return kHandleSignalExclusive;
1708   return result;
1709 }
1710 
1711 #if !SANITIZER_GO
1712 void *internal_start_thread(void *(*func)(void *arg), void *arg) {
1713   // Start the thread with signals blocked, otherwise it can steal user signals.
1714   __sanitizer_sigset_t set, old;
1715   internal_sigfillset(&set);
1716 #if SANITIZER_LINUX && !SANITIZER_ANDROID
1717   // Glibc uses SIGSETXID signal during setuid call. If this signal is blocked
1718   // on any thread, setuid call hangs (see test/tsan/setuid.c).
1719   internal_sigdelset(&set, 33);
1720 #endif
1721   internal_sigprocmask(SIG_SETMASK, &set, &old);
1722   void *th;
1723   real_pthread_create(&th, nullptr, func, arg);
1724   internal_sigprocmask(SIG_SETMASK, &old, nullptr);
1725   return th;
1726 }
1727 
1728 void internal_join_thread(void *th) {
1729   real_pthread_join(th, nullptr);
1730 }
1731 #else
1732 void *internal_start_thread(void *(*func)(void *), void *arg) { return 0; }
1733 
1734 void internal_join_thread(void *th) {}
1735 #endif
1736 
1737 #if defined(__aarch64__)
1738 // Android headers in the older NDK releases miss this definition.
1739 struct __sanitizer_esr_context {
1740   struct _aarch64_ctx head;
1741   uint64_t esr;
1742 };
1743 
1744 static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
1745   static const u32 kEsrMagic = 0x45535201;
1746   u8 *aux = ucontext->uc_mcontext.__reserved;
1747   while (true) {
1748     _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
1749     if (ctx->size == 0) break;
1750     if (ctx->magic == kEsrMagic) {
1751       *esr = ((__sanitizer_esr_context *)ctx)->esr;
1752       return true;
1753     }
1754     aux += ctx->size;
1755   }
1756   return false;
1757 }
1758 #endif
1759 
1760 #if SANITIZER_OPENBSD
1761 using Context = sigcontext;
1762 #else
1763 using Context = ucontext_t;
1764 #endif
1765 
1766 SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
1767   Context *ucontext = (Context *)context;
1768 #if defined(__x86_64__) || defined(__i386__)
1769   static const uptr PF_WRITE = 1U << 1;
1770 #if SANITIZER_FREEBSD
1771   uptr err = ucontext->uc_mcontext.mc_err;
1772 #elif SANITIZER_NETBSD
1773   uptr err = ucontext->uc_mcontext.__gregs[_REG_ERR];
1774 #elif SANITIZER_OPENBSD
1775   uptr err = ucontext->sc_err;
1776 #elif SANITIZER_SOLARIS && defined(__i386__)
1777   const int Err = 13;
1778   uptr err = ucontext->uc_mcontext.gregs[Err];
1779 #else
1780   uptr err = ucontext->uc_mcontext.gregs[REG_ERR];
1781 #endif // SANITIZER_FREEBSD
1782   return err & PF_WRITE ? WRITE : READ;
1783 #elif defined(__mips__)
1784   uint32_t *exception_source;
1785   uint32_t faulty_instruction;
1786   uint32_t op_code;
1787 
1788   exception_source = (uint32_t *)ucontext->uc_mcontext.pc;
1789   faulty_instruction = (uint32_t)(*exception_source);
1790 
1791   op_code = (faulty_instruction >> 26) & 0x3f;
1792 
1793   // FIXME: Add support for FPU, microMIPS, DSP, MSA memory instructions.
1794   switch (op_code) {
1795     case 0x28:  // sb
1796     case 0x29:  // sh
1797     case 0x2b:  // sw
1798     case 0x3f:  // sd
1799 #if __mips_isa_rev < 6
1800     case 0x2c:  // sdl
1801     case 0x2d:  // sdr
1802     case 0x2a:  // swl
1803     case 0x2e:  // swr
1804 #endif
1805       return SignalContext::WRITE;
1806 
1807     case 0x20:  // lb
1808     case 0x24:  // lbu
1809     case 0x21:  // lh
1810     case 0x25:  // lhu
1811     case 0x23:  // lw
1812     case 0x27:  // lwu
1813     case 0x37:  // ld
1814 #if __mips_isa_rev < 6
1815     case 0x1a:  // ldl
1816     case 0x1b:  // ldr
1817     case 0x22:  // lwl
1818     case 0x26:  // lwr
1819 #endif
1820       return SignalContext::READ;
1821 #if __mips_isa_rev == 6
1822     case 0x3b:  // pcrel
1823       op_code = (faulty_instruction >> 19) & 0x3;
1824       switch (op_code) {
1825         case 0x1:  // lwpc
1826         case 0x2:  // lwupc
1827           return SignalContext::READ;
1828       }
1829 #endif
1830   }
1831   return SignalContext::UNKNOWN;
1832 #elif defined(__arm__)
1833   static const uptr FSR_WRITE = 1U << 11;
1834   uptr fsr = ucontext->uc_mcontext.error_code;
1835   return fsr & FSR_WRITE ? WRITE : READ;
1836 #elif defined(__aarch64__)
1837   static const u64 ESR_ELx_WNR = 1U << 6;
1838   u64 esr;
1839   if (!Aarch64GetESR(ucontext, &esr)) return UNKNOWN;
1840   return esr & ESR_ELx_WNR ? WRITE : READ;
1841 #elif defined(__sparc__)
1842   // Decode the instruction to determine the access type.
1843   // From OpenSolaris $SRC/uts/sun4/os/trap.c (get_accesstype).
1844 #if SANITIZER_SOLARIS
1845   uptr pc = ucontext->uc_mcontext.gregs[REG_PC];
1846 #else
1847   // Historical BSDism here.
1848   struct sigcontext *scontext = (struct sigcontext *)context;
1849 #if defined(__arch64__)
1850   uptr pc = scontext->sigc_regs.tpc;
1851 #else
1852   uptr pc = scontext->si_regs.pc;
1853 #endif
1854 #endif
1855   u32 instr = *(u32 *)pc;
1856   return (instr >> 21) & 1 ? WRITE: READ;
1857 #else
1858   (void)ucontext;
1859   return UNKNOWN;  // FIXME: Implement.
1860 #endif
1861 }
1862 
1863 bool SignalContext::IsTrueFaultingAddress() const {
1864   auto si = static_cast<const siginfo_t *>(siginfo);
1865   // SIGSEGV signals without a true fault address have si_code set to 128.
1866   return si->si_signo == SIGSEGV && si->si_code != 128;
1867 }
1868 
1869 void SignalContext::DumpAllRegisters(void *context) {
1870   // FIXME: Implement this.
1871 }
1872 
1873 static void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
1874 #if SANITIZER_NETBSD
1875   // This covers all NetBSD architectures
1876   ucontext_t *ucontext = (ucontext_t *)context;
1877   *pc = _UC_MACHINE_PC(ucontext);
1878   *bp = _UC_MACHINE_FP(ucontext);
1879   *sp = _UC_MACHINE_SP(ucontext);
1880 #elif defined(__arm__)
1881   ucontext_t *ucontext = (ucontext_t*)context;
1882   *pc = ucontext->uc_mcontext.arm_pc;
1883   *bp = ucontext->uc_mcontext.arm_fp;
1884   *sp = ucontext->uc_mcontext.arm_sp;
1885 #elif defined(__aarch64__)
1886   ucontext_t *ucontext = (ucontext_t*)context;
1887   *pc = ucontext->uc_mcontext.pc;
1888   *bp = ucontext->uc_mcontext.regs[29];
1889   *sp = ucontext->uc_mcontext.sp;
1890 #elif defined(__hppa__)
1891   ucontext_t *ucontext = (ucontext_t*)context;
1892   *pc = ucontext->uc_mcontext.sc_iaoq[0];
1893   /* GCC uses %r3 whenever a frame pointer is needed.  */
1894   *bp = ucontext->uc_mcontext.sc_gr[3];
1895   *sp = ucontext->uc_mcontext.sc_gr[30];
1896 #elif defined(__x86_64__)
1897 # if SANITIZER_FREEBSD
1898   ucontext_t *ucontext = (ucontext_t*)context;
1899   *pc = ucontext->uc_mcontext.mc_rip;
1900   *bp = ucontext->uc_mcontext.mc_rbp;
1901   *sp = ucontext->uc_mcontext.mc_rsp;
1902 #elif SANITIZER_OPENBSD
1903   sigcontext *ucontext = (sigcontext *)context;
1904   *pc = ucontext->sc_rip;
1905   *bp = ucontext->sc_rbp;
1906   *sp = ucontext->sc_rsp;
1907 # else
1908   ucontext_t *ucontext = (ucontext_t*)context;
1909   *pc = ucontext->uc_mcontext.gregs[REG_RIP];
1910   *bp = ucontext->uc_mcontext.gregs[REG_RBP];
1911   *sp = ucontext->uc_mcontext.gregs[REG_RSP];
1912 # endif
1913 #elif defined(__i386__)
1914 # if SANITIZER_FREEBSD
1915   ucontext_t *ucontext = (ucontext_t*)context;
1916   *pc = ucontext->uc_mcontext.mc_eip;
1917   *bp = ucontext->uc_mcontext.mc_ebp;
1918   *sp = ucontext->uc_mcontext.mc_esp;
1919 #elif SANITIZER_OPENBSD
1920   sigcontext *ucontext = (sigcontext *)context;
1921   *pc = ucontext->sc_eip;
1922   *bp = ucontext->sc_ebp;
1923   *sp = ucontext->sc_esp;
1924 # else
1925   ucontext_t *ucontext = (ucontext_t*)context;
1926 # if SANITIZER_SOLARIS
1927   /* Use the numeric values: the symbolic ones are undefined by llvm
1928      include/llvm/Support/Solaris.h.  */
1929 # ifndef REG_EIP
1930 #  define REG_EIP 14 // REG_PC
1931 # endif
1932 # ifndef REG_EBP
1933 #  define REG_EBP  6 // REG_FP
1934 # endif
1935 # ifndef REG_ESP
1936 #  define REG_ESP 17 // REG_SP
1937 # endif
1938 # endif
1939   *pc = ucontext->uc_mcontext.gregs[REG_EIP];
1940   *bp = ucontext->uc_mcontext.gregs[REG_EBP];
1941   *sp = ucontext->uc_mcontext.gregs[REG_ESP];
1942 # endif
1943 #elif defined(__powerpc__) || defined(__powerpc64__)
1944   ucontext_t *ucontext = (ucontext_t*)context;
1945   *pc = ucontext->uc_mcontext.regs->nip;
1946   *sp = ucontext->uc_mcontext.regs->gpr[PT_R1];
1947   // The powerpc{,64}-linux ABIs do not specify r31 as the frame
1948   // pointer, but GCC always uses r31 when we need a frame pointer.
1949   *bp = ucontext->uc_mcontext.regs->gpr[PT_R31];
1950 #elif defined(__sparc__)
1951 #if defined(__arch64__) || defined(__sparcv9)
1952 #define STACK_BIAS 2047
1953 #else
1954 #define STACK_BIAS 0
1955 # endif
1956 # if SANITIZER_SOLARIS
1957   ucontext_t *ucontext = (ucontext_t *)context;
1958   *pc = ucontext->uc_mcontext.gregs[REG_PC];
1959   *sp = ucontext->uc_mcontext.gregs[REG_O6] + STACK_BIAS;
1960 #else
1961   // Historical BSDism here.
1962   struct sigcontext *scontext = (struct sigcontext *)context;
1963 #if defined(__arch64__)
1964   *pc = scontext->sigc_regs.tpc;
1965   *sp = scontext->sigc_regs.u_regs[14] + STACK_BIAS;
1966 #else
1967   *pc = scontext->si_regs.pc;
1968   *sp = scontext->si_regs.u_regs[14];
1969 #endif
1970 # endif
1971   *bp = (uptr)((uhwptr *)*sp)[14] + STACK_BIAS;
1972 #elif defined(__mips__)
1973   ucontext_t *ucontext = (ucontext_t*)context;
1974   *pc = ucontext->uc_mcontext.pc;
1975   *bp = ucontext->uc_mcontext.gregs[30];
1976   *sp = ucontext->uc_mcontext.gregs[29];
1977 #elif defined(__s390__)
1978   ucontext_t *ucontext = (ucontext_t*)context;
1979 # if defined(__s390x__)
1980   *pc = ucontext->uc_mcontext.psw.addr;
1981 # else
1982   *pc = ucontext->uc_mcontext.psw.addr & 0x7fffffff;
1983 # endif
1984   *bp = ucontext->uc_mcontext.gregs[11];
1985   *sp = ucontext->uc_mcontext.gregs[15];
1986 #elif defined(__riscv)
1987   ucontext_t *ucontext = (ucontext_t*)context;
1988   *pc = ucontext->uc_mcontext.__gregs[REG_PC];
1989   *bp = ucontext->uc_mcontext.__gregs[REG_S0];
1990   *sp = ucontext->uc_mcontext.__gregs[REG_SP];
1991 #else
1992 # error "Unsupported arch"
1993 #endif
1994 }
1995 
1996 void SignalContext::InitPcSpBp() { GetPcSpBp(context, &pc, &sp, &bp); }
1997 
1998 void InitializePlatformEarly() {
1999   // Do nothing.
2000 }
2001 
2002 void MaybeReexec() {
2003   // No need to re-exec on Linux.
2004 }
2005 
2006 void CheckASLR() {
2007 #if SANITIZER_NETBSD
2008   int mib[3];
2009   int paxflags;
2010   uptr len = sizeof(paxflags);
2011 
2012   mib[0] = CTL_PROC;
2013   mib[1] = internal_getpid();
2014   mib[2] = PROC_PID_PAXFLAGS;
2015 
2016   if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2017     Printf("sysctl failed\n");
2018     Die();
2019   }
2020 
2021   if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_ASLR)) {
2022     Printf("This sanitizer is not compatible with enabled ASLR\n");
2023     Die();
2024   }
2025 #elif SANITIZER_PPC64V2
2026   // Disable ASLR for Linux PPC64LE.
2027   int old_personality = personality(0xffffffff);
2028   if (old_personality != -1 && (old_personality & ADDR_NO_RANDOMIZE) == 0) {
2029     VReport(1, "WARNING: Program is being run with address space layout "
2030                "randomization (ASLR) enabled which prevents the thread and "
2031                "memory sanitizers from working on powerpc64le.\n"
2032                "ASLR will be disabled and the program re-executed.\n");
2033     CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
2034     ReExec();
2035   }
2036 #elif SANITIZER_FREEBSD
2037   int aslr_pie;
2038   uptr len = sizeof(aslr_pie);
2039 #if SANITIZER_WORDSIZE == 64
2040   if (UNLIKELY(internal_sysctlbyname("kern.elf64.aslr.pie_enable",
2041       &aslr_pie, &len, NULL, 0) == -1)) {
2042     // We're making things less 'dramatic' here since
2043     // the OID is not necessarily guaranteed to be here
2044     // just yet regarding FreeBSD release
2045     return;
2046   }
2047 
2048   if (aslr_pie > 0) {
2049     Printf("This sanitizer is not compatible with enabled ASLR "
2050            "and binaries compiled with PIE\n");
2051     Die();
2052   }
2053 #endif
2054   // there might be 32 bits compat for 64 bits
2055   if (UNLIKELY(internal_sysctlbyname("kern.elf32.aslr.pie_enable",
2056       &aslr_pie, &len, NULL, 0) == -1)) {
2057     return;
2058   }
2059 
2060   if (aslr_pie > 0) {
2061     Printf("This sanitizer is not compatible with enabled ASLR "
2062            "and binaries compiled with PIE\n");
2063     Die();
2064   }
2065 #else
2066   // Do nothing
2067 #endif
2068 }
2069 
2070 void CheckMPROTECT() {
2071 #if SANITIZER_NETBSD
2072   int mib[3];
2073   int paxflags;
2074   uptr len = sizeof(paxflags);
2075 
2076   mib[0] = CTL_PROC;
2077   mib[1] = internal_getpid();
2078   mib[2] = PROC_PID_PAXFLAGS;
2079 
2080   if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2081     Printf("sysctl failed\n");
2082     Die();
2083   }
2084 
2085   if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_MPROTECT)) {
2086     Printf("This sanitizer is not compatible with enabled MPROTECT\n");
2087     Die();
2088   }
2089 #else
2090   // Do nothing
2091 #endif
2092 }
2093 
2094 void PrintModuleMap() { }
2095 
2096 void CheckNoDeepBind(const char *filename, int flag) {
2097 #ifdef RTLD_DEEPBIND
2098   if (flag & RTLD_DEEPBIND) {
2099     Report(
2100         "You are trying to dlopen a %s shared library with RTLD_DEEPBIND flag"
2101         " which is incompatibe with sanitizer runtime "
2102         "(see https://github.com/google/sanitizers/issues/611 for details"
2103         "). If you want to run %s library under sanitizers please remove "
2104         "RTLD_DEEPBIND from dlopen flags.\n",
2105         filename, filename);
2106     Die();
2107   }
2108 #endif
2109 }
2110 
2111 uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
2112                               uptr *largest_gap_found,
2113                               uptr *max_occupied_addr) {
2114   UNREACHABLE("FindAvailableMemoryRange is not available");
2115   return 0;
2116 }
2117 
2118 bool GetRandom(void *buffer, uptr length, bool blocking) {
2119   if (!buffer || !length || length > 256)
2120     return false;
2121 #if SANITIZER_USE_GETENTROPY
2122   uptr rnd = getentropy(buffer, length);
2123   int rverrno = 0;
2124   if (internal_iserror(rnd, &rverrno) && rverrno == EFAULT)
2125     return false;
2126   else if (rnd == 0)
2127     return true;
2128 #endif // SANITIZER_USE_GETENTROPY
2129 
2130 #if SANITIZER_USE_GETRANDOM
2131   static atomic_uint8_t skip_getrandom_syscall;
2132   if (!atomic_load_relaxed(&skip_getrandom_syscall)) {
2133     // Up to 256 bytes, getrandom will not be interrupted.
2134     uptr res = internal_syscall(SYSCALL(getrandom), buffer, length,
2135                                 blocking ? 0 : GRND_NONBLOCK);
2136     int rverrno = 0;
2137     if (internal_iserror(res, &rverrno) && rverrno == ENOSYS)
2138       atomic_store_relaxed(&skip_getrandom_syscall, 1);
2139     else if (res == length)
2140       return true;
2141   }
2142 #endif // SANITIZER_USE_GETRANDOM
2143   // Up to 256 bytes, a read off /dev/urandom will not be interrupted.
2144   // blocking is moot here, O_NONBLOCK has no effect when opening /dev/urandom.
2145   uptr fd = internal_open("/dev/urandom", O_RDONLY);
2146   if (internal_iserror(fd))
2147     return false;
2148   uptr res = internal_read(fd, buffer, length);
2149   if (internal_iserror(res))
2150     return false;
2151   internal_close(fd);
2152   return true;
2153 }
2154 
2155 } // namespace __sanitizer
2156 
2157 #endif
2158