1 //===-- sanitizer_linux.cc ------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is shared between AddressSanitizer and ThreadSanitizer
11 // run-time libraries and implements linux-specific functions from
12 // sanitizer_libc.h.
13 //===----------------------------------------------------------------------===//
14 
15 #include "sanitizer_platform.h"
16 
17 #if SANITIZER_FREEBSD || SANITIZER_LINUX
18 
19 #include "sanitizer_common.h"
20 #include "sanitizer_flags.h"
21 #include "sanitizer_internal_defs.h"
22 #include "sanitizer_libc.h"
23 #include "sanitizer_linux.h"
24 #include "sanitizer_mutex.h"
25 #include "sanitizer_placement_new.h"
26 #include "sanitizer_procmaps.h"
27 #include "sanitizer_stacktrace.h"
28 #include "sanitizer_symbolizer.h"
29 
30 #if !SANITIZER_FREEBSD
31 #include <asm/param.h>
32 #endif
33 
34 // For mips64, syscall(__NR_stat) fills the buffer in the 'struct kernel_stat'
35 // format. Struct kernel_stat is defined as 'struct stat' in asm/stat.h. To
36 // access stat from asm/stat.h, without conflicting with definition in
37 // sys/stat.h, we use this trick.
38 #if defined(__mips64)
39 #include <asm/unistd.h>
40 #include <sys/types.h>
41 #define stat kernel_stat
42 #include <asm/stat.h>
43 #undef stat
44 #endif
45 
46 #include <dlfcn.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <link.h>
50 #include <pthread.h>
51 #include <sched.h>
52 #include <sys/mman.h>
53 #include <sys/ptrace.h>
54 #include <sys/resource.h>
55 #include <sys/stat.h>
56 #include <sys/syscall.h>
57 #include <sys/time.h>
58 #include <sys/types.h>
59 #include <ucontext.h>
60 #include <unistd.h>
61 
62 #if SANITIZER_FREEBSD
63 #include <sys/sysctl.h>
64 #include <machine/atomic.h>
65 extern "C" {
66 // <sys/umtx.h> must be included after <errno.h> and <sys/types.h> on
67 // FreeBSD 9.2 and 10.0.
68 #include <sys/umtx.h>
69 }
70 extern char **environ;  // provided by crt1
71 #endif  // SANITIZER_FREEBSD
72 
73 #if !SANITIZER_ANDROID
74 #include <sys/signal.h>
75 #endif
76 
77 #if SANITIZER_LINUX
78 // <linux/time.h>
79 struct kernel_timeval {
80   long tv_sec;
81   long tv_usec;
82 };
83 
84 // <linux/futex.h> is broken on some linux distributions.
85 const int FUTEX_WAIT = 0;
86 const int FUTEX_WAKE = 1;
87 #endif  // SANITIZER_LINUX
88 
89 // Are we using 32-bit or 64-bit Linux syscalls?
90 // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
91 // but it still needs to use 64-bit syscalls.
92 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__powerpc64__) || \
93     SANITIZER_WORDSIZE == 64)
94 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
95 #else
96 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
97 #endif
98 
99 namespace __sanitizer {
100 
101 #if SANITIZER_LINUX && defined(__x86_64__)
102 #include "sanitizer_syscall_linux_x86_64.inc"
103 #elif SANITIZER_LINUX && defined(__aarch64__)
104 #include "sanitizer_syscall_linux_aarch64.inc"
105 #else
106 #include "sanitizer_syscall_generic.inc"
107 #endif
108 
109 // --------------- sanitizer_libc.h
internal_mmap(void * addr,uptr length,int prot,int flags,int fd,OFF_T offset)110 uptr internal_mmap(void *addr, uptr length, int prot, int flags, int fd,
111                    OFF_T offset) {
112 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
113   return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
114                           offset);
115 #else
116   // mmap2 specifies file offset in 4096-byte units.
117   CHECK(IsAligned(offset, 4096));
118   return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
119                           offset / 4096);
120 #endif
121 }
122 
internal_munmap(void * addr,uptr length)123 uptr internal_munmap(void *addr, uptr length) {
124   return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
125 }
126 
internal_mprotect(void * addr,uptr length,int prot)127 int internal_mprotect(void *addr, uptr length, int prot) {
128   return internal_syscall(SYSCALL(mprotect), (uptr)addr, length, prot);
129 }
130 
internal_close(fd_t fd)131 uptr internal_close(fd_t fd) {
132   return internal_syscall(SYSCALL(close), fd);
133 }
134 
internal_open(const char * filename,int flags)135 uptr internal_open(const char *filename, int flags) {
136 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
137   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags);
138 #else
139   return internal_syscall(SYSCALL(open), (uptr)filename, flags);
140 #endif
141 }
142 
internal_open(const char * filename,int flags,u32 mode)143 uptr internal_open(const char *filename, int flags, u32 mode) {
144 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
145   return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags,
146                           mode);
147 #else
148   return internal_syscall(SYSCALL(open), (uptr)filename, flags, mode);
149 #endif
150 }
151 
internal_read(fd_t fd,void * buf,uptr count)152 uptr internal_read(fd_t fd, void *buf, uptr count) {
153   sptr res;
154   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(read), fd, (uptr)buf,
155                count));
156   return res;
157 }
158 
internal_write(fd_t fd,const void * buf,uptr count)159 uptr internal_write(fd_t fd, const void *buf, uptr count) {
160   sptr res;
161   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf,
162                count));
163   return res;
164 }
165 
internal_ftruncate(fd_t fd,uptr size)166 uptr internal_ftruncate(fd_t fd, uptr size) {
167   sptr res;
168   HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd,
169                (OFF_T)size));
170   return res;
171 }
172 
173 #if !SANITIZER_LINUX_USES_64BIT_SYSCALLS && !SANITIZER_FREEBSD
stat64_to_stat(struct stat64 * in,struct stat * out)174 static void stat64_to_stat(struct stat64 *in, struct stat *out) {
175   internal_memset(out, 0, sizeof(*out));
176   out->st_dev = in->st_dev;
177   out->st_ino = in->st_ino;
178   out->st_mode = in->st_mode;
179   out->st_nlink = in->st_nlink;
180   out->st_uid = in->st_uid;
181   out->st_gid = in->st_gid;
182   out->st_rdev = in->st_rdev;
183   out->st_size = in->st_size;
184   out->st_blksize = in->st_blksize;
185   out->st_blocks = in->st_blocks;
186   out->st_atime = in->st_atime;
187   out->st_mtime = in->st_mtime;
188   out->st_ctime = in->st_ctime;
189   out->st_ino = in->st_ino;
190 }
191 #endif
192 
193 #if defined(__mips64)
kernel_stat_to_stat(struct kernel_stat * in,struct stat * out)194 static void kernel_stat_to_stat(struct kernel_stat *in, struct stat *out) {
195   internal_memset(out, 0, sizeof(*out));
196   out->st_dev = in->st_dev;
197   out->st_ino = in->st_ino;
198   out->st_mode = in->st_mode;
199   out->st_nlink = in->st_nlink;
200   out->st_uid = in->st_uid;
201   out->st_gid = in->st_gid;
202   out->st_rdev = in->st_rdev;
203   out->st_size = in->st_size;
204   out->st_blksize = in->st_blksize;
205   out->st_blocks = in->st_blocks;
206   out->st_atime = in->st_atime_nsec;
207   out->st_mtime = in->st_mtime_nsec;
208   out->st_ctime = in->st_ctime_nsec;
209   out->st_ino = in->st_ino;
210 }
211 #endif
212 
internal_stat(const char * path,void * buf)213 uptr internal_stat(const char *path, void *buf) {
214 #if SANITIZER_FREEBSD
215   return internal_syscall(SYSCALL(stat), path, buf);
216 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
217   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
218                           (uptr)buf, 0);
219 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
220 # if defined(__mips64)
221   // For mips64, stat syscall fills buffer in the format of kernel_stat
222   struct kernel_stat kbuf;
223   int res = internal_syscall(SYSCALL(stat), path, &kbuf);
224   kernel_stat_to_stat(&kbuf, (struct stat *)buf);
225   return res;
226 # else
227   return internal_syscall(SYSCALL(stat), (uptr)path, (uptr)buf);
228 # endif
229 #else
230   struct stat64 buf64;
231   int res = internal_syscall(SYSCALL(stat64), path, &buf64);
232   stat64_to_stat(&buf64, (struct stat *)buf);
233   return res;
234 #endif
235 }
236 
internal_lstat(const char * path,void * buf)237 uptr internal_lstat(const char *path, void *buf) {
238 #if SANITIZER_FREEBSD
239   return internal_syscall(SYSCALL(lstat), path, buf);
240 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
241   return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
242                          (uptr)buf, AT_SYMLINK_NOFOLLOW);
243 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
244   return internal_syscall(SYSCALL(lstat), (uptr)path, (uptr)buf);
245 #else
246   struct stat64 buf64;
247   int res = internal_syscall(SYSCALL(lstat64), path, &buf64);
248   stat64_to_stat(&buf64, (struct stat *)buf);
249   return res;
250 #endif
251 }
252 
internal_fstat(fd_t fd,void * buf)253 uptr internal_fstat(fd_t fd, void *buf) {
254 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
255   return internal_syscall(SYSCALL(fstat), fd, (uptr)buf);
256 #else
257   struct stat64 buf64;
258   int res = internal_syscall(SYSCALL(fstat64), fd, &buf64);
259   stat64_to_stat(&buf64, (struct stat *)buf);
260   return res;
261 #endif
262 }
263 
internal_filesize(fd_t fd)264 uptr internal_filesize(fd_t fd) {
265   struct stat st;
266   if (internal_fstat(fd, &st))
267     return -1;
268   return (uptr)st.st_size;
269 }
270 
internal_dup2(int oldfd,int newfd)271 uptr internal_dup2(int oldfd, int newfd) {
272 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
273   return internal_syscall(SYSCALL(dup3), oldfd, newfd, 0);
274 #else
275   return internal_syscall(SYSCALL(dup2), oldfd, newfd);
276 #endif
277 }
278 
internal_readlink(const char * path,char * buf,uptr bufsize)279 uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
280 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
281   return internal_syscall(SYSCALL(readlinkat), AT_FDCWD,
282                           (uptr)path, (uptr)buf, bufsize);
283 #else
284   return internal_syscall(SYSCALL(readlink), (uptr)path, (uptr)buf, bufsize);
285 #endif
286 }
287 
internal_unlink(const char * path)288 uptr internal_unlink(const char *path) {
289 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
290   return internal_syscall(SYSCALL(unlinkat), AT_FDCWD, (uptr)path, 0);
291 #else
292   return internal_syscall(SYSCALL(unlink), (uptr)path);
293 #endif
294 }
295 
internal_rename(const char * oldpath,const char * newpath)296 uptr internal_rename(const char *oldpath, const char *newpath) {
297 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
298   return internal_syscall(SYSCALL(renameat), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
299                           (uptr)newpath);
300 #else
301   return internal_syscall(SYSCALL(rename), (uptr)oldpath, (uptr)newpath);
302 #endif
303 }
304 
internal_sched_yield()305 uptr internal_sched_yield() {
306   return internal_syscall(SYSCALL(sched_yield));
307 }
308 
internal__exit(int exitcode)309 void internal__exit(int exitcode) {
310 #if SANITIZER_FREEBSD
311   internal_syscall(SYSCALL(exit), exitcode);
312 #else
313   internal_syscall(SYSCALL(exit_group), exitcode);
314 #endif
315   Die();  // Unreachable.
316 }
317 
internal_execve(const char * filename,char * const argv[],char * const envp[])318 uptr internal_execve(const char *filename, char *const argv[],
319                      char *const envp[]) {
320   return internal_syscall(SYSCALL(execve), (uptr)filename, (uptr)argv,
321                           (uptr)envp);
322 }
323 
324 // ----------------- sanitizer_common.h
FileExists(const char * filename)325 bool FileExists(const char *filename) {
326   struct stat st;
327 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
328   if (internal_syscall(SYSCALL(newfstatat), AT_FDCWD, filename, &st, 0))
329 #else
330   if (internal_stat(filename, &st))
331 #endif
332     return false;
333   // Sanity check: filename is a regular file.
334   return S_ISREG(st.st_mode);
335 }
336 
GetTid()337 uptr GetTid() {
338 #if SANITIZER_FREEBSD
339   return (uptr)pthread_self();
340 #else
341   return internal_syscall(SYSCALL(gettid));
342 #endif
343 }
344 
NanoTime()345 u64 NanoTime() {
346 #if SANITIZER_FREEBSD
347   timeval tv;
348 #else
349   kernel_timeval tv;
350 #endif
351   internal_memset(&tv, 0, sizeof(tv));
352   internal_syscall(SYSCALL(gettimeofday), (uptr)&tv, 0);
353   return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
354 }
355 
356 // Like getenv, but reads env directly from /proc (on Linux) or parses the
357 // 'environ' array (on FreeBSD) and does not use libc. This function should be
358 // called first inside __asan_init.
GetEnv(const char * name)359 const char *GetEnv(const char *name) {
360 #if SANITIZER_FREEBSD
361   if (::environ != 0) {
362     uptr NameLen = internal_strlen(name);
363     for (char **Env = ::environ; *Env != 0; Env++) {
364       if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
365         return (*Env) + NameLen + 1;
366     }
367   }
368   return 0;  // Not found.
369 #elif SANITIZER_LINUX
370   static char *environ;
371   static uptr len;
372   static bool inited;
373   if (!inited) {
374     inited = true;
375     uptr environ_size;
376     if (!ReadFileToBuffer("/proc/self/environ", &environ, &environ_size, &len))
377       environ = nullptr;
378   }
379   if (!environ || len == 0) return nullptr;
380   uptr namelen = internal_strlen(name);
381   const char *p = environ;
382   while (*p != '\0') {  // will happen at the \0\0 that terminates the buffer
383     // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
384     const char* endp =
385         (char*)internal_memchr(p, '\0', len - (p - environ));
386     if (!endp)  // this entry isn't NUL terminated
387       return nullptr;
388     else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=')  // Match.
389       return p + namelen + 1;  // point after =
390     p = endp + 1;
391   }
392   return nullptr;  // Not found.
393 #else
394 #error "Unsupported platform"
395 #endif
396 }
397 
398 extern "C" {
399   SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
400 }
401 
402 #if !SANITIZER_GO
ReadNullSepFileToArray(const char * path,char *** arr,int arr_size)403 static void ReadNullSepFileToArray(const char *path, char ***arr,
404                                    int arr_size) {
405   char *buff;
406   uptr buff_size;
407   uptr buff_len;
408   *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
409   if (!ReadFileToBuffer(path, &buff, &buff_size, &buff_len, 1024 * 1024)) {
410     (*arr)[0] = nullptr;
411     return;
412   }
413   (*arr)[0] = buff;
414   int count, i;
415   for (count = 1, i = 1; ; i++) {
416     if (buff[i] == 0) {
417       if (buff[i+1] == 0) break;
418       (*arr)[count] = &buff[i+1];
419       CHECK_LE(count, arr_size - 1);  // FIXME: make this more flexible.
420       count++;
421     }
422   }
423   (*arr)[count] = nullptr;
424 }
425 #endif
426 
GetArgsAndEnv(char *** argv,char *** envp)427 static void GetArgsAndEnv(char*** argv, char*** envp) {
428 #if !SANITIZER_GO
429   if (&__libc_stack_end) {
430 #endif
431     uptr* stack_end = (uptr*)__libc_stack_end;
432     int argc = *stack_end;
433     *argv = (char**)(stack_end + 1);
434     *envp = (char**)(stack_end + argc + 2);
435 #if !SANITIZER_GO
436   } else {
437     static const int kMaxArgv = 2000, kMaxEnvp = 2000;
438     ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
439     ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
440   }
441 #endif
442 }
443 
ReExec()444 void ReExec() {
445   char **argv, **envp;
446   GetArgsAndEnv(&argv, &envp);
447   uptr rv = internal_execve("/proc/self/exe", argv, envp);
448   int rverrno;
449   CHECK_EQ(internal_iserror(rv, &rverrno), true);
450   Printf("execve failed, errno %d\n", rverrno);
451   Die();
452 }
453 
454 enum MutexState {
455   MtxUnlocked = 0,
456   MtxLocked = 1,
457   MtxSleeping = 2
458 };
459 
BlockingMutex()460 BlockingMutex::BlockingMutex() {
461   internal_memset(this, 0, sizeof(*this));
462 }
463 
Lock()464 void BlockingMutex::Lock() {
465   CHECK_EQ(owner_, 0);
466   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
467   if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked)
468     return;
469   while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) {
470 #if SANITIZER_FREEBSD
471     _umtx_op(m, UMTX_OP_WAIT_UINT, MtxSleeping, 0, 0);
472 #else
473     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAIT, MtxSleeping, 0, 0, 0);
474 #endif
475   }
476 }
477 
Unlock()478 void BlockingMutex::Unlock() {
479   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
480   u32 v = atomic_exchange(m, MtxUnlocked, memory_order_relaxed);
481   CHECK_NE(v, MtxUnlocked);
482   if (v == MtxSleeping) {
483 #if SANITIZER_FREEBSD
484     _umtx_op(m, UMTX_OP_WAKE, 1, 0, 0);
485 #else
486     internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAKE, 1, 0, 0, 0);
487 #endif
488   }
489 }
490 
CheckLocked()491 void BlockingMutex::CheckLocked() {
492   atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
493   CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed));
494 }
495 
496 // ----------------- sanitizer_linux.h
497 // The actual size of this structure is specified by d_reclen.
498 // Note that getdents64 uses a different structure format. We only provide the
499 // 32-bit syscall here.
500 struct linux_dirent {
501 #if SANITIZER_X32 || defined(__aarch64__)
502   u64 d_ino;
503   u64 d_off;
504 #else
505   unsigned long      d_ino;
506   unsigned long      d_off;
507 #endif
508   unsigned short     d_reclen;
509 #ifdef __aarch64__
510   unsigned char      d_type;
511 #endif
512   char               d_name[256];
513 };
514 
515 // Syscall wrappers.
internal_ptrace(int request,int pid,void * addr,void * data)516 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
517   return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
518                           (uptr)data);
519 }
520 
internal_waitpid(int pid,int * status,int options)521 uptr internal_waitpid(int pid, int *status, int options) {
522   return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
523                           0 /* rusage */);
524 }
525 
internal_getpid()526 uptr internal_getpid() {
527   return internal_syscall(SYSCALL(getpid));
528 }
529 
internal_getppid()530 uptr internal_getppid() {
531   return internal_syscall(SYSCALL(getppid));
532 }
533 
internal_getdents(fd_t fd,struct linux_dirent * dirp,unsigned int count)534 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
535 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
536   return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
537 #else
538   return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
539 #endif
540 }
541 
internal_lseek(fd_t fd,OFF_T offset,int whence)542 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
543   return internal_syscall(SYSCALL(lseek), fd, offset, whence);
544 }
545 
546 #if SANITIZER_LINUX
internal_prctl(int option,uptr arg2,uptr arg3,uptr arg4,uptr arg5)547 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
548   return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
549 }
550 #endif
551 
internal_sigaltstack(const struct sigaltstack * ss,struct sigaltstack * oss)552 uptr internal_sigaltstack(const struct sigaltstack *ss,
553                          struct sigaltstack *oss) {
554   return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
555 }
556 
internal_fork()557 int internal_fork() {
558 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
559   return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
560 #else
561   return internal_syscall(SYSCALL(fork));
562 #endif
563 }
564 
565 #if SANITIZER_LINUX
566 #define SA_RESTORER 0x04000000
567 // Doesn't set sa_restorer, use with caution (see below).
internal_sigaction_norestorer(int signum,const void * act,void * oldact)568 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
569   __sanitizer_kernel_sigaction_t k_act, k_oldact;
570   internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
571   internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
572   const __sanitizer_sigaction *u_act = (const __sanitizer_sigaction *)act;
573   __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
574   if (u_act) {
575     k_act.handler = u_act->handler;
576     k_act.sigaction = u_act->sigaction;
577     internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
578                     sizeof(__sanitizer_kernel_sigset_t));
579     // Without SA_RESTORER kernel ignores the calls (probably returns EINVAL).
580     k_act.sa_flags = u_act->sa_flags | SA_RESTORER;
581     // FIXME: most often sa_restorer is unset, however the kernel requires it
582     // to point to a valid signal restorer that calls the rt_sigreturn syscall.
583     // If sa_restorer passed to the kernel is NULL, the program may crash upon
584     // signal delivery or fail to unwind the stack in the signal handler.
585     // libc implementation of sigaction() passes its own restorer to
586     // rt_sigaction, so we need to do the same (we'll need to reimplement the
587     // restorers; for x86_64 the restorer address can be obtained from
588     // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
589     k_act.sa_restorer = u_act->sa_restorer;
590   }
591 
592   uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
593       (uptr)(u_act ? &k_act : nullptr),
594       (uptr)(u_oldact ? &k_oldact : nullptr),
595       (uptr)sizeof(__sanitizer_kernel_sigset_t));
596 
597   if ((result == 0) && u_oldact) {
598     u_oldact->handler = k_oldact.handler;
599     u_oldact->sigaction = k_oldact.sigaction;
600     internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
601                     sizeof(__sanitizer_kernel_sigset_t));
602     u_oldact->sa_flags = k_oldact.sa_flags;
603     u_oldact->sa_restorer = k_oldact.sa_restorer;
604   }
605   return result;
606 }
607 #endif  // SANITIZER_LINUX
608 
internal_sigprocmask(int how,__sanitizer_sigset_t * set,__sanitizer_sigset_t * oldset)609 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
610     __sanitizer_sigset_t *oldset) {
611 #if SANITIZER_FREEBSD
612   return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
613 #else
614   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
615   __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
616   return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how,
617                           (uptr)&k_set->sig[0], (uptr)&k_oldset->sig[0],
618                           sizeof(__sanitizer_kernel_sigset_t));
619 #endif
620 }
621 
internal_sigfillset(__sanitizer_sigset_t * set)622 void internal_sigfillset(__sanitizer_sigset_t *set) {
623   internal_memset(set, 0xff, sizeof(*set));
624 }
625 
626 #if SANITIZER_LINUX
internal_sigdelset(__sanitizer_sigset_t * set,int signum)627 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
628   signum -= 1;
629   CHECK_GE(signum, 0);
630   CHECK_LT(signum, sizeof(*set) * 8);
631   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
632   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
633   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
634   k_set->sig[idx] &= ~(1 << bit);
635 }
636 #endif  // SANITIZER_LINUX
637 
638 // ThreadLister implementation.
ThreadLister(int pid)639 ThreadLister::ThreadLister(int pid)
640   : pid_(pid),
641     descriptor_(-1),
642     buffer_(4096),
643     error_(true),
644     entry_((struct linux_dirent *)buffer_.data()),
645     bytes_read_(0) {
646   char task_directory_path[80];
647   internal_snprintf(task_directory_path, sizeof(task_directory_path),
648                     "/proc/%d/task/", pid);
649   uptr openrv = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
650   if (internal_iserror(openrv)) {
651     error_ = true;
652     Report("Can't open /proc/%d/task for reading.\n", pid);
653   } else {
654     error_ = false;
655     descriptor_ = openrv;
656   }
657 }
658 
GetNextTID()659 int ThreadLister::GetNextTID() {
660   int tid = -1;
661   do {
662     if (error_)
663       return -1;
664     if ((char *)entry_ >= &buffer_[bytes_read_] && !GetDirectoryEntries())
665       return -1;
666     if (entry_->d_ino != 0 && entry_->d_name[0] >= '0' &&
667         entry_->d_name[0] <= '9') {
668       // Found a valid tid.
669       tid = (int)internal_atoll(entry_->d_name);
670     }
671     entry_ = (struct linux_dirent *)(((char *)entry_) + entry_->d_reclen);
672   } while (tid < 0);
673   return tid;
674 }
675 
Reset()676 void ThreadLister::Reset() {
677   if (error_ || descriptor_ < 0)
678     return;
679   internal_lseek(descriptor_, 0, SEEK_SET);
680 }
681 
~ThreadLister()682 ThreadLister::~ThreadLister() {
683   if (descriptor_ >= 0)
684     internal_close(descriptor_);
685 }
686 
error()687 bool ThreadLister::error() { return error_; }
688 
GetDirectoryEntries()689 bool ThreadLister::GetDirectoryEntries() {
690   CHECK_GE(descriptor_, 0);
691   CHECK_NE(error_, true);
692   bytes_read_ = internal_getdents(descriptor_,
693                                   (struct linux_dirent *)buffer_.data(),
694                                   buffer_.size());
695   if (internal_iserror(bytes_read_)) {
696     Report("Can't read directory entries from /proc/%d/task.\n", pid_);
697     error_ = true;
698     return false;
699   } else if (bytes_read_ == 0) {
700     return false;
701   }
702   entry_ = (struct linux_dirent *)buffer_.data();
703   return true;
704 }
705 
GetPageSize()706 uptr GetPageSize() {
707 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
708   return EXEC_PAGESIZE;
709 #else
710   return sysconf(_SC_PAGESIZE);  // EXEC_PAGESIZE may not be trustworthy.
711 #endif
712 }
713 
ReadBinaryName(char * buf,uptr buf_len)714 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
715 #if SANITIZER_FREEBSD
716   const int Mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1 };
717   const char *default_module_name = "kern.proc.pathname";
718   size_t Size = buf_len;
719   bool IsErr = (sysctl(Mib, ARRAY_SIZE(Mib), buf, &Size, NULL, 0) != 0);
720   int readlink_error = IsErr ? errno : 0;
721   uptr module_name_len = Size;
722 #else
723   const char *default_module_name = "/proc/self/exe";
724   uptr module_name_len = internal_readlink(
725       default_module_name, buf, buf_len);
726   int readlink_error;
727   bool IsErr = internal_iserror(module_name_len, &readlink_error);
728 #endif
729   if (IsErr) {
730     // We can't read binary name for some reason, assume it's unknown.
731     Report("WARNING: reading executable name failed with errno %d, "
732            "some stack frames may not be symbolized\n", readlink_error);
733     module_name_len = internal_snprintf(buf, buf_len, "%s",
734                                         default_module_name);
735     CHECK_LT(module_name_len, buf_len);
736   }
737   return module_name_len;
738 }
739 
ReadLongProcessName(char * buf,uptr buf_len)740 uptr ReadLongProcessName(/*out*/ char *buf, uptr buf_len) {
741 #if SANITIZER_LINUX
742   char *tmpbuf;
743   uptr tmpsize;
744   uptr tmplen;
745   if (ReadFileToBuffer("/proc/self/cmdline", &tmpbuf, &tmpsize, &tmplen,
746                        1024 * 1024)) {
747     internal_strncpy(buf, tmpbuf, buf_len);
748     UnmapOrDie(tmpbuf, tmpsize);
749     return internal_strlen(buf);
750   }
751 #endif
752   return ReadBinaryName(buf, buf_len);
753 }
754 
755 // Match full names of the form /path/to/base_name{-,.}*
LibraryNameIs(const char * full_name,const char * base_name)756 bool LibraryNameIs(const char *full_name, const char *base_name) {
757   const char *name = full_name;
758   // Strip path.
759   while (*name != '\0') name++;
760   while (name > full_name && *name != '/') name--;
761   if (*name == '/') name++;
762   uptr base_name_length = internal_strlen(base_name);
763   if (internal_strncmp(name, base_name, base_name_length)) return false;
764   return (name[base_name_length] == '-' || name[base_name_length] == '.');
765 }
766 
767 #if !SANITIZER_ANDROID
768 // Call cb for each region mapped by map.
ForEachMappedRegion(link_map * map,void (* cb)(const void *,uptr))769 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
770   CHECK_NE(map, nullptr);
771 #if !SANITIZER_FREEBSD
772   typedef ElfW(Phdr) Elf_Phdr;
773   typedef ElfW(Ehdr) Elf_Ehdr;
774 #endif  // !SANITIZER_FREEBSD
775   char *base = (char *)map->l_addr;
776   Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
777   char *phdrs = base + ehdr->e_phoff;
778   char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
779 
780   // Find the segment with the minimum base so we can "relocate" the p_vaddr
781   // fields.  Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
782   // objects have a non-zero base.
783   uptr preferred_base = (uptr)-1;
784   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
785     Elf_Phdr *phdr = (Elf_Phdr *)iter;
786     if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
787       preferred_base = (uptr)phdr->p_vaddr;
788   }
789 
790   // Compute the delta from the real base to get a relocation delta.
791   sptr delta = (uptr)base - preferred_base;
792   // Now we can figure out what the loader really mapped.
793   for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
794     Elf_Phdr *phdr = (Elf_Phdr *)iter;
795     if (phdr->p_type == PT_LOAD) {
796       uptr seg_start = phdr->p_vaddr + delta;
797       uptr seg_end = seg_start + phdr->p_memsz;
798       // None of these values are aligned.  We consider the ragged edges of the
799       // load command as defined, since they are mapped from the file.
800       seg_start = RoundDownTo(seg_start, GetPageSizeCached());
801       seg_end = RoundUpTo(seg_end, GetPageSizeCached());
802       cb((void *)seg_start, seg_end - seg_start);
803     }
804   }
805 }
806 #endif
807 
808 #if defined(__x86_64__) && SANITIZER_LINUX
809 // We cannot use glibc's clone wrapper, because it messes with the child
810 // task's TLS. It writes the PID and TID of the child task to its thread
811 // descriptor, but in our case the child task shares the thread descriptor with
812 // the parent (because we don't know how to allocate a new thread
813 // descriptor to keep glibc happy). So the stock version of clone(), when
814 // used with CLONE_VM, would end up corrupting the parent's thread descriptor.
internal_clone(int (* fn)(void *),void * child_stack,int flags,void * arg,int * parent_tidptr,void * newtls,int * child_tidptr)815 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
816                     int *parent_tidptr, void *newtls, int *child_tidptr) {
817   long long res;
818   if (!fn || !child_stack)
819     return -EINVAL;
820   CHECK_EQ(0, (uptr)child_stack % 16);
821   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
822   ((unsigned long long *)child_stack)[0] = (uptr)fn;
823   ((unsigned long long *)child_stack)[1] = (uptr)arg;
824   register void *r8 __asm__("r8") = newtls;
825   register int *r10 __asm__("r10") = child_tidptr;
826   __asm__ __volatile__(
827                        /* %rax = syscall(%rax = SYSCALL(clone),
828                         *                %rdi = flags,
829                         *                %rsi = child_stack,
830                         *                %rdx = parent_tidptr,
831                         *                %r8  = new_tls,
832                         *                %r10 = child_tidptr)
833                         */
834                        "syscall\n"
835 
836                        /* if (%rax != 0)
837                         *   return;
838                         */
839                        "testq  %%rax,%%rax\n"
840                        "jnz    1f\n"
841 
842                        /* In the child. Terminate unwind chain. */
843                        // XXX: We should also terminate the CFI unwind chain
844                        // here. Unfortunately clang 3.2 doesn't support the
845                        // necessary CFI directives, so we skip that part.
846                        "xorq   %%rbp,%%rbp\n"
847 
848                        /* Call "fn(arg)". */
849                        "popq   %%rax\n"
850                        "popq   %%rdi\n"
851                        "call   *%%rax\n"
852 
853                        /* Call _exit(%rax). */
854                        "movq   %%rax,%%rdi\n"
855                        "movq   %2,%%rax\n"
856                        "syscall\n"
857 
858                        /* Return to parent. */
859                      "1:\n"
860                        : "=a" (res)
861                        : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
862                          "S"(child_stack),
863                          "D"(flags),
864                          "d"(parent_tidptr),
865                          "r"(r8),
866                          "r"(r10)
867                        : "rsp", "memory", "r11", "rcx");
868   return res;
869 }
870 #elif defined(__mips__)
internal_clone(int (* fn)(void *),void * child_stack,int flags,void * arg,int * parent_tidptr,void * newtls,int * child_tidptr)871 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
872                     int *parent_tidptr, void *newtls, int *child_tidptr) {
873   long long res;
874   if (!fn || !child_stack)
875     return -EINVAL;
876   CHECK_EQ(0, (uptr)child_stack % 16);
877   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
878   ((unsigned long long *)child_stack)[0] = (uptr)fn;
879   ((unsigned long long *)child_stack)[1] = (uptr)arg;
880   register void *a3 __asm__("$7") = newtls;
881   register int *a4 __asm__("$8") = child_tidptr;
882   // We don't have proper CFI directives here because it requires alot of code
883   // for very marginal benefits.
884   __asm__ __volatile__(
885                        /* $v0 = syscall($v0 = __NR_clone,
886                         * $a0 = flags,
887                         * $a1 = child_stack,
888                         * $a2 = parent_tidptr,
889                         * $a3 = new_tls,
890                         * $a4 = child_tidptr)
891                         */
892                        ".cprestore 16;\n"
893                        "move $4,%1;\n"
894                        "move $5,%2;\n"
895                        "move $6,%3;\n"
896                        "move $7,%4;\n"
897                        /* Store the fifth argument on stack
898                         * if we are using 32-bit abi.
899                         */
900 #if SANITIZER_WORDSIZE == 32
901                        "lw %5,16($29);\n"
902 #else
903                        "move $8,%5;\n"
904 #endif
905                        "li $2,%6;\n"
906                        "syscall;\n"
907 
908                        /* if ($v0 != 0)
909                         * return;
910                         */
911                        "bnez $2,1f;\n"
912 
913                        /* Call "fn(arg)". */
914                        "ld $25,0($29);\n"
915                        "ld $4,8($29);\n"
916                        "jal $25;\n"
917 
918                        /* Call _exit($v0). */
919                        "move $4,$2;\n"
920                        "li $2,%7;\n"
921                        "syscall;\n"
922 
923                        /* Return to parent. */
924                      "1:\n"
925                        : "=r" (res)
926                        : "r"(flags),
927                          "r"(child_stack),
928                          "r"(parent_tidptr),
929                          "r"(a3),
930                          "r"(a4),
931                          "i"(__NR_clone),
932                          "i"(__NR_exit)
933                        : "memory", "$29" );
934   return res;
935 }
936 #elif defined(__aarch64__)
internal_clone(int (* fn)(void *),void * child_stack,int flags,void * arg,int * parent_tidptr,void * newtls,int * child_tidptr)937 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
938                     int *parent_tidptr, void *newtls, int *child_tidptr) {
939   long long res;
940   if (!fn || !child_stack)
941     return -EINVAL;
942   CHECK_EQ(0, (uptr)child_stack % 16);
943   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
944   ((unsigned long long *)child_stack)[0] = (uptr)fn;
945   ((unsigned long long *)child_stack)[1] = (uptr)arg;
946 
947   register int (*__fn)(void *)  __asm__("x0") = fn;
948   register void *__stack __asm__("x1") = child_stack;
949   register int   __flags __asm__("x2") = flags;
950   register void *__arg   __asm__("x3") = arg;
951   register int  *__ptid  __asm__("x4") = parent_tidptr;
952   register void *__tls   __asm__("x5") = newtls;
953   register int  *__ctid  __asm__("x6") = child_tidptr;
954 
955   __asm__ __volatile__(
956                        "mov x0,x2\n" /* flags  */
957                        "mov x2,x4\n" /* ptid  */
958                        "mov x3,x5\n" /* tls  */
959                        "mov x4,x6\n" /* ctid  */
960                        "mov x8,%9\n" /* clone  */
961 
962                        "svc 0x0\n"
963 
964                        /* if (%r0 != 0)
965                         *   return %r0;
966                         */
967                        "cmp x0, #0\n"
968                        "bne 1f\n"
969 
970                        /* In the child, now. Call "fn(arg)". */
971                        "ldp x1, x0, [sp], #16\n"
972                        "blr x1\n"
973 
974                        /* Call _exit(%r0).  */
975                        "mov x8, %10\n"
976                        "svc 0x0\n"
977                      "1:\n"
978 
979                        : "=r" (res)
980                        : "i"(-EINVAL),
981                          "r"(__fn), "r"(__stack), "r"(__flags), "r"(__arg),
982                          "r"(__ptid), "r"(__tls), "r"(__ctid),
983                          "i"(__NR_clone), "i"(__NR_exit)
984                        : "x30", "memory");
985   return res;
986 }
987 #elif defined(__powerpc64__)
internal_clone(int (* fn)(void *),void * child_stack,int flags,void * arg,int * parent_tidptr,void * newtls,int * child_tidptr)988 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
989                    int *parent_tidptr, void *newtls, int *child_tidptr) {
990   long long res;
991 /* Stack frame offsets.  */
992 #if _CALL_ELF != 2
993 #define FRAME_MIN_SIZE         112
994 #define FRAME_TOC_SAVE         40
995 #else
996 #define FRAME_MIN_SIZE         32
997 #define FRAME_TOC_SAVE         24
998 #endif
999   if (!fn || !child_stack)
1000     return -EINVAL;
1001   CHECK_EQ(0, (uptr)child_stack % 16);
1002   child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1003   ((unsigned long long *)child_stack)[0] = (uptr)fn;
1004   ((unsigned long long *)child_stack)[1] = (uptr)arg;
1005 
1006   register int (*__fn)(void *) __asm__("r3") = fn;
1007   register void *__cstack      __asm__("r4") = child_stack;
1008   register int __flags         __asm__("r5") = flags;
1009   register void * __arg        __asm__("r6") = arg;
1010   register int * __ptidptr     __asm__("r7") = parent_tidptr;
1011   register void * __newtls     __asm__("r8") = newtls;
1012   register int * __ctidptr     __asm__("r9") = child_tidptr;
1013 
1014  __asm__ __volatile__(
1015            /* fn, arg, child_stack are saved acrVoss the syscall */
1016            "mr 28, %5\n\t"
1017            "mr 29, %6\n\t"
1018            "mr 27, %8\n\t"
1019 
1020            /* syscall
1021              r3 == flags
1022              r4 == child_stack
1023              r5 == parent_tidptr
1024              r6 == newtls
1025              r7 == child_tidptr */
1026            "mr 3, %7\n\t"
1027            "mr 5, %9\n\t"
1028            "mr 6, %10\n\t"
1029            "mr 7, %11\n\t"
1030            "li 0, %3\n\t"
1031            "sc\n\t"
1032 
1033            /* Test if syscall was successful */
1034            "cmpdi  cr1, 3, 0\n\t"
1035            "crandc cr1*4+eq, cr1*4+eq, cr0*4+so\n\t"
1036            "bne-   cr1, 1f\n\t"
1037 
1038            /* Do the function call */
1039            "std   2, %13(1)\n\t"
1040 #if _CALL_ELF != 2
1041            "ld    0, 0(28)\n\t"
1042            "ld    2, 8(28)\n\t"
1043            "mtctr 0\n\t"
1044 #else
1045            "mr    12, 28\n\t"
1046            "mtctr 12\n\t"
1047 #endif
1048            "mr    3, 27\n\t"
1049            "bctrl\n\t"
1050            "ld    2, %13(1)\n\t"
1051 
1052            /* Call _exit(r3) */
1053            "li 0, %4\n\t"
1054            "sc\n\t"
1055 
1056            /* Return to parent */
1057            "1:\n\t"
1058            "mr %0, 3\n\t"
1059              : "=r" (res)
1060              : "0" (-1), "i" (EINVAL),
1061                "i" (__NR_clone), "i" (__NR_exit),
1062                "r" (__fn), "r" (__cstack), "r" (__flags),
1063                "r" (__arg), "r" (__ptidptr), "r" (__newtls),
1064                "r" (__ctidptr), "i" (FRAME_MIN_SIZE), "i" (FRAME_TOC_SAVE)
1065              : "cr0", "cr1", "memory", "ctr",
1066                "r0", "r29", "r27", "r28");
1067   return res;
1068 }
1069 #endif  // defined(__x86_64__) && SANITIZER_LINUX
1070 
1071 #if SANITIZER_ANDROID
1072 #if __ANDROID_API__ < 21
1073 extern "C" __attribute__((weak)) int dl_iterate_phdr(
1074     int (*)(struct dl_phdr_info *, size_t, void *), void *);
1075 #endif
1076 
dl_iterate_phdr_test_cb(struct dl_phdr_info * info,size_t size,void * data)1077 static int dl_iterate_phdr_test_cb(struct dl_phdr_info *info, size_t size,
1078                                    void *data) {
1079   // Any name starting with "lib" indicates a bug in L where library base names
1080   // are returned instead of paths.
1081   if (info->dlpi_name && info->dlpi_name[0] == 'l' &&
1082       info->dlpi_name[1] == 'i' && info->dlpi_name[2] == 'b') {
1083     *(bool *)data = true;
1084     return 1;
1085   }
1086   return 0;
1087 }
1088 
1089 static atomic_uint32_t android_api_level;
1090 
AndroidDetectApiLevel()1091 static AndroidApiLevel AndroidDetectApiLevel() {
1092   if (!&dl_iterate_phdr)
1093     return ANDROID_KITKAT; // K or lower
1094   bool base_name_seen = false;
1095   dl_iterate_phdr(dl_iterate_phdr_test_cb, &base_name_seen);
1096   if (base_name_seen)
1097     return ANDROID_LOLLIPOP_MR1; // L MR1
1098   return ANDROID_POST_LOLLIPOP;   // post-L
1099   // Plain L (API level 21) is completely broken wrt ASan and not very
1100   // interesting to detect.
1101 }
1102 
AndroidGetApiLevel()1103 AndroidApiLevel AndroidGetApiLevel() {
1104   AndroidApiLevel level =
1105       (AndroidApiLevel)atomic_load(&android_api_level, memory_order_relaxed);
1106   if (level) return level;
1107   level = AndroidDetectApiLevel();
1108   atomic_store(&android_api_level, level, memory_order_relaxed);
1109   return level;
1110 }
1111 
1112 #endif
1113 
IsDeadlySignal(int signum)1114 bool IsDeadlySignal(int signum) {
1115   if (common_flags()->handle_abort && signum == SIGABRT)
1116     return true;
1117   if (common_flags()->handle_sigill && signum == SIGILL)
1118     return true;
1119   if (common_flags()->handle_sigfpe && signum == SIGFPE)
1120     return true;
1121   return (signum == SIGSEGV || signum == SIGBUS) && common_flags()->handle_segv;
1122 }
1123 
1124 #ifndef SANITIZER_GO
internal_start_thread(void (* func)(void * arg),void * arg)1125 void *internal_start_thread(void(*func)(void *arg), void *arg) {
1126   // Start the thread with signals blocked, otherwise it can steal user signals.
1127   __sanitizer_sigset_t set, old;
1128   internal_sigfillset(&set);
1129 #if SANITIZER_LINUX && !SANITIZER_ANDROID
1130   // Glibc uses SIGSETXID signal during setuid call. If this signal is blocked
1131   // on any thread, setuid call hangs (see test/tsan/setuid.c).
1132   internal_sigdelset(&set, 33);
1133 #endif
1134   internal_sigprocmask(SIG_SETMASK, &set, &old);
1135   void *th;
1136   real_pthread_create(&th, nullptr, (void*(*)(void *arg))func, arg);
1137   internal_sigprocmask(SIG_SETMASK, &old, nullptr);
1138   return th;
1139 }
1140 
internal_join_thread(void * th)1141 void internal_join_thread(void *th) {
1142   real_pthread_join(th, nullptr);
1143 }
1144 #else
internal_start_thread(void (* func)(void *),void * arg)1145 void *internal_start_thread(void (*func)(void *), void *arg) { return 0; }
1146 
internal_join_thread(void * th)1147 void internal_join_thread(void *th) {}
1148 #endif
1149 
GetPcSpBp(void * context,uptr * pc,uptr * sp,uptr * bp)1150 void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
1151 #if defined(__arm__)
1152   ucontext_t *ucontext = (ucontext_t*)context;
1153   *pc = ucontext->uc_mcontext.arm_pc;
1154   *bp = ucontext->uc_mcontext.arm_fp;
1155   *sp = ucontext->uc_mcontext.arm_sp;
1156 #elif defined(__aarch64__)
1157   ucontext_t *ucontext = (ucontext_t*)context;
1158   *pc = ucontext->uc_mcontext.pc;
1159   *bp = ucontext->uc_mcontext.regs[29];
1160   *sp = ucontext->uc_mcontext.sp;
1161 #elif defined(__hppa__)
1162   ucontext_t *ucontext = (ucontext_t*)context;
1163   *pc = ucontext->uc_mcontext.sc_iaoq[0];
1164   /* GCC uses %r3 whenever a frame pointer is needed.  */
1165   *bp = ucontext->uc_mcontext.sc_gr[3];
1166   *sp = ucontext->uc_mcontext.sc_gr[30];
1167 #elif defined(__x86_64__)
1168 # if SANITIZER_FREEBSD
1169   ucontext_t *ucontext = (ucontext_t*)context;
1170   *pc = ucontext->uc_mcontext.mc_rip;
1171   *bp = ucontext->uc_mcontext.mc_rbp;
1172   *sp = ucontext->uc_mcontext.mc_rsp;
1173 # else
1174   ucontext_t *ucontext = (ucontext_t*)context;
1175   *pc = ucontext->uc_mcontext.gregs[REG_RIP];
1176   *bp = ucontext->uc_mcontext.gregs[REG_RBP];
1177   *sp = ucontext->uc_mcontext.gregs[REG_RSP];
1178 # endif
1179 #elif defined(__i386__)
1180 # if SANITIZER_FREEBSD
1181   ucontext_t *ucontext = (ucontext_t*)context;
1182   *pc = ucontext->uc_mcontext.mc_eip;
1183   *bp = ucontext->uc_mcontext.mc_ebp;
1184   *sp = ucontext->uc_mcontext.mc_esp;
1185 # else
1186   ucontext_t *ucontext = (ucontext_t*)context;
1187   *pc = ucontext->uc_mcontext.gregs[REG_EIP];
1188   *bp = ucontext->uc_mcontext.gregs[REG_EBP];
1189   *sp = ucontext->uc_mcontext.gregs[REG_ESP];
1190 # endif
1191 #elif defined(__powerpc__) || defined(__powerpc64__)
1192   ucontext_t *ucontext = (ucontext_t*)context;
1193   *pc = ucontext->uc_mcontext.regs->nip;
1194   *sp = ucontext->uc_mcontext.regs->gpr[PT_R1];
1195   // The powerpc{,64}-linux ABIs do not specify r31 as the frame
1196   // pointer, but GCC always uses r31 when we need a frame pointer.
1197   *bp = ucontext->uc_mcontext.regs->gpr[PT_R31];
1198 #elif defined(__sparc__)
1199   ucontext_t *ucontext = (ucontext_t*)context;
1200   uptr *stk_ptr;
1201 # if defined (__arch64__)
1202   *pc = ucontext->uc_mcontext.mc_gregs[MC_PC];
1203   *sp = ucontext->uc_mcontext.mc_gregs[MC_O6];
1204   stk_ptr = (uptr *) (*sp + 2047);
1205   *bp = stk_ptr[15];
1206 # else
1207   *pc = ucontext->uc_mcontext.gregs[REG_PC];
1208   *sp = ucontext->uc_mcontext.gregs[REG_O6];
1209   stk_ptr = (uptr *) *sp;
1210   *bp = stk_ptr[15];
1211 # endif
1212 #elif defined(__mips__)
1213   ucontext_t *ucontext = (ucontext_t*)context;
1214   *pc = ucontext->uc_mcontext.pc;
1215   *bp = ucontext->uc_mcontext.gregs[30];
1216   *sp = ucontext->uc_mcontext.gregs[29];
1217 #else
1218 # error "Unsupported arch"
1219 #endif
1220 }
1221 
DisableReexec()1222 void DisableReexec() {
1223   // No need to re-exec on Linux.
1224 }
1225 
MaybeReexec()1226 void MaybeReexec() {
1227   // No need to re-exec on Linux.
1228 }
1229 
1230 } // namespace __sanitizer
1231 
1232 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX
1233