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 #if SANITIZER_FREEBSD || SANITIZER_LINUX
17
18 #include "sanitizer_common.h"
19 #include "sanitizer_flags.h"
20 #include "sanitizer_internal_defs.h"
21 #include "sanitizer_libc.h"
22 #include "sanitizer_linux.h"
23 #include "sanitizer_mutex.h"
24 #include "sanitizer_placement_new.h"
25 #include "sanitizer_procmaps.h"
26 #include "sanitizer_stacktrace.h"
27 #include "sanitizer_symbolizer.h"
28
29 #if !SANITIZER_FREEBSD
30 #include <asm/param.h>
31 #endif
32
33 #include <dlfcn.h>
34 #include <errno.h>
35 #include <fcntl.h>
36 #if !SANITIZER_ANDROID
37 #include <link.h>
38 #endif
39 #include <pthread.h>
40 #include <sched.h>
41 #include <sys/mman.h>
42 #include <sys/ptrace.h>
43 #include <sys/resource.h>
44 #include <sys/stat.h>
45 #include <sys/syscall.h>
46 #include <sys/time.h>
47 #include <sys/types.h>
48 #include <unistd.h>
49
50 #if SANITIZER_FREEBSD
51 #include <sys/sysctl.h>
52 #include <machine/atomic.h>
53 extern "C" {
54 // <sys/umtx.h> must be included after <errno.h> and <sys/types.h> on
55 // FreeBSD 9.2 and 10.0.
56 #include <sys/umtx.h>
57 }
58 extern char **environ; // provided by crt1
59 #endif // SANITIZER_FREEBSD
60
61 #if !SANITIZER_ANDROID
62 #include <sys/signal.h>
63 #endif
64
65 #if SANITIZER_ANDROID
66 #include <android/log.h>
67 #include <sys/system_properties.h>
68 #endif
69
70 #if SANITIZER_LINUX
71 // <linux/time.h>
72 struct kernel_timeval {
73 long tv_sec;
74 long tv_usec;
75 };
76
77 // <linux/futex.h> is broken on some linux distributions.
78 const int FUTEX_WAIT = 0;
79 const int FUTEX_WAKE = 1;
80 #endif // SANITIZER_LINUX
81
82 // Are we using 32-bit or 64-bit Linux syscalls?
83 // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
84 // but it still needs to use 64-bit syscalls.
85 #if SANITIZER_LINUX && (defined(__x86_64__) || SANITIZER_WORDSIZE == 64)
86 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
87 #else
88 # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
89 #endif
90
91 namespace __sanitizer {
92
93 #if SANITIZER_LINUX && defined(__x86_64__)
94 #include "sanitizer_syscall_linux_x86_64.inc"
95 #else
96 #include "sanitizer_syscall_generic.inc"
97 #endif
98
99 // --------------- sanitizer_libc.h
internal_mmap(void * addr,uptr length,int prot,int flags,int fd,u64 offset)100 uptr internal_mmap(void *addr, uptr length, int prot, int flags,
101 int fd, u64 offset) {
102 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
103 return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
104 offset);
105 #else
106 return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
107 offset);
108 #endif
109 }
110
internal_munmap(void * addr,uptr length)111 uptr internal_munmap(void *addr, uptr length) {
112 return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
113 }
114
internal_close(fd_t fd)115 uptr internal_close(fd_t fd) {
116 return internal_syscall(SYSCALL(close), fd);
117 }
118
internal_open(const char * filename,int flags)119 uptr internal_open(const char *filename, int flags) {
120 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
121 return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags);
122 #else
123 return internal_syscall(SYSCALL(open), (uptr)filename, flags);
124 #endif
125 }
126
internal_open(const char * filename,int flags,u32 mode)127 uptr internal_open(const char *filename, int flags, u32 mode) {
128 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
129 return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags,
130 mode);
131 #else
132 return internal_syscall(SYSCALL(open), (uptr)filename, flags, mode);
133 #endif
134 }
135
OpenFile(const char * filename,bool write)136 uptr OpenFile(const char *filename, bool write) {
137 return internal_open(filename,
138 write ? O_RDWR | O_CREAT /*| O_CLOEXEC*/ : O_RDONLY, 0660);
139 }
140
internal_read(fd_t fd,void * buf,uptr count)141 uptr internal_read(fd_t fd, void *buf, uptr count) {
142 sptr res;
143 HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(read), fd, (uptr)buf,
144 count));
145 return res;
146 }
147
internal_write(fd_t fd,const void * buf,uptr count)148 uptr internal_write(fd_t fd, const void *buf, uptr count) {
149 sptr res;
150 HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf,
151 count));
152 return res;
153 }
154
internal_ftruncate(fd_t fd,uptr size)155 uptr internal_ftruncate(fd_t fd, uptr size) {
156 sptr res;
157 HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd, size));
158 return res;
159 }
160
161 #if !SANITIZER_LINUX_USES_64BIT_SYSCALLS && !SANITIZER_FREEBSD
stat64_to_stat(struct stat64 * in,struct stat * out)162 static void stat64_to_stat(struct stat64 *in, struct stat *out) {
163 internal_memset(out, 0, sizeof(*out));
164 out->st_dev = in->st_dev;
165 out->st_ino = in->st_ino;
166 out->st_mode = in->st_mode;
167 out->st_nlink = in->st_nlink;
168 out->st_uid = in->st_uid;
169 out->st_gid = in->st_gid;
170 out->st_rdev = in->st_rdev;
171 out->st_size = in->st_size;
172 out->st_blksize = in->st_blksize;
173 out->st_blocks = in->st_blocks;
174 out->st_atime = in->st_atime;
175 out->st_mtime = in->st_mtime;
176 out->st_ctime = in->st_ctime;
177 out->st_ino = in->st_ino;
178 }
179 #endif
180
internal_stat(const char * path,void * buf)181 uptr internal_stat(const char *path, void *buf) {
182 #if SANITIZER_FREEBSD
183 return internal_syscall(SYSCALL(stat), path, buf);
184 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
185 return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
186 (uptr)buf, 0);
187 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
188 return internal_syscall(SYSCALL(stat), (uptr)path, (uptr)buf);
189 #else
190 struct stat64 buf64;
191 int res = internal_syscall(SYSCALL(stat64), path, &buf64);
192 stat64_to_stat(&buf64, (struct stat *)buf);
193 return res;
194 #endif
195 }
196
internal_lstat(const char * path,void * buf)197 uptr internal_lstat(const char *path, void *buf) {
198 #if SANITIZER_FREEBSD
199 return internal_syscall(SYSCALL(lstat), path, buf);
200 #elif SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
201 return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path,
202 (uptr)buf, AT_SYMLINK_NOFOLLOW);
203 #elif SANITIZER_LINUX_USES_64BIT_SYSCALLS
204 return internal_syscall(SYSCALL(lstat), (uptr)path, (uptr)buf);
205 #else
206 struct stat64 buf64;
207 int res = internal_syscall(SYSCALL(lstat64), path, &buf64);
208 stat64_to_stat(&buf64, (struct stat *)buf);
209 return res;
210 #endif
211 }
212
internal_fstat(fd_t fd,void * buf)213 uptr internal_fstat(fd_t fd, void *buf) {
214 #if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
215 return internal_syscall(SYSCALL(fstat), fd, (uptr)buf);
216 #else
217 struct stat64 buf64;
218 int res = internal_syscall(SYSCALL(fstat64), fd, &buf64);
219 stat64_to_stat(&buf64, (struct stat *)buf);
220 return res;
221 #endif
222 }
223
internal_filesize(fd_t fd)224 uptr internal_filesize(fd_t fd) {
225 struct stat st;
226 if (internal_fstat(fd, &st))
227 return -1;
228 return (uptr)st.st_size;
229 }
230
internal_dup2(int oldfd,int newfd)231 uptr internal_dup2(int oldfd, int newfd) {
232 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
233 return internal_syscall(SYSCALL(dup3), oldfd, newfd, 0);
234 #else
235 return internal_syscall(SYSCALL(dup2), oldfd, newfd);
236 #endif
237 }
238
internal_readlink(const char * path,char * buf,uptr bufsize)239 uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
240 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
241 return internal_syscall(SYSCALL(readlinkat), AT_FDCWD,
242 (uptr)path, (uptr)buf, bufsize);
243 #else
244 return internal_syscall(SYSCALL(readlink), (uptr)path, (uptr)buf, bufsize);
245 #endif
246 }
247
internal_unlink(const char * path)248 uptr internal_unlink(const char *path) {
249 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
250 return internal_syscall(SYSCALL(unlinkat), AT_FDCWD, (uptr)path, 0);
251 #else
252 return internal_syscall(SYSCALL(unlink), (uptr)path);
253 #endif
254 }
255
internal_rename(const char * oldpath,const char * newpath)256 uptr internal_rename(const char *oldpath, const char *newpath) {
257 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
258 return internal_syscall(SYSCALL(renameat), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
259 (uptr)newpath);
260 #else
261 return internal_syscall(SYSCALL(rename), (uptr)oldpath, (uptr)newpath);
262 #endif
263 }
264
internal_sched_yield()265 uptr internal_sched_yield() {
266 return internal_syscall(SYSCALL(sched_yield));
267 }
268
internal__exit(int exitcode)269 void internal__exit(int exitcode) {
270 #if SANITIZER_FREEBSD
271 internal_syscall(SYSCALL(exit), exitcode);
272 #else
273 internal_syscall(SYSCALL(exit_group), exitcode);
274 #endif
275 Die(); // Unreachable.
276 }
277
internal_execve(const char * filename,char * const argv[],char * const envp[])278 uptr internal_execve(const char *filename, char *const argv[],
279 char *const envp[]) {
280 return internal_syscall(SYSCALL(execve), (uptr)filename, (uptr)argv,
281 (uptr)envp);
282 }
283
284 // ----------------- sanitizer_common.h
FileExists(const char * filename)285 bool FileExists(const char *filename) {
286 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
287 struct stat st;
288 if (internal_syscall(SYSCALL(newfstatat), AT_FDCWD, filename, &st, 0))
289 return false;
290 #else
291 struct stat st;
292 if (internal_stat(filename, &st))
293 return false;
294 // Sanity check: filename is a regular file.
295 return S_ISREG(st.st_mode);
296 #endif
297 }
298
GetTid()299 uptr GetTid() {
300 #if SANITIZER_FREEBSD
301 return (uptr)pthread_self();
302 #else
303 return internal_syscall(SYSCALL(gettid));
304 #endif
305 }
306
NanoTime()307 u64 NanoTime() {
308 #if SANITIZER_FREEBSD
309 timeval tv;
310 #else
311 kernel_timeval tv;
312 #endif
313 internal_memset(&tv, 0, sizeof(tv));
314 internal_syscall(SYSCALL(gettimeofday), (uptr)&tv, 0);
315 return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
316 }
317
318 // Like getenv, but reads env directly from /proc (on Linux) or parses the
319 // 'environ' array (on FreeBSD) and does not use libc. This function should be
320 // called first inside __asan_init.
GetEnv(const char * name)321 const char *GetEnv(const char *name) {
322 #if SANITIZER_FREEBSD
323 if (::environ != 0) {
324 uptr NameLen = internal_strlen(name);
325 for (char **Env = ::environ; *Env != 0; Env++) {
326 if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
327 return (*Env) + NameLen + 1;
328 }
329 }
330 return 0; // Not found.
331 #elif SANITIZER_LINUX
332 static char *environ;
333 static uptr len;
334 static bool inited;
335 if (!inited) {
336 inited = true;
337 uptr environ_size;
338 len = ReadFileToBuffer("/proc/self/environ",
339 &environ, &environ_size, 1 << 26);
340 }
341 if (!environ || len == 0) return 0;
342 uptr namelen = internal_strlen(name);
343 const char *p = environ;
344 while (*p != '\0') { // will happen at the \0\0 that terminates the buffer
345 // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
346 const char* endp =
347 (char*)internal_memchr(p, '\0', len - (p - environ));
348 if (endp == 0) // this entry isn't NUL terminated
349 return 0;
350 else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=') // Match.
351 return p + namelen + 1; // point after =
352 p = endp + 1;
353 }
354 return 0; // Not found.
355 #else
356 #error "Unsupported platform"
357 #endif
358 }
359
360 extern "C" {
361 SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
362 }
363
364 #if !SANITIZER_GO
ReadNullSepFileToArray(const char * path,char *** arr,int arr_size)365 static void ReadNullSepFileToArray(const char *path, char ***arr,
366 int arr_size) {
367 char *buff;
368 uptr buff_size = 0;
369 *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
370 ReadFileToBuffer(path, &buff, &buff_size, 1024 * 1024);
371 (*arr)[0] = buff;
372 int count, i;
373 for (count = 1, i = 1; ; i++) {
374 if (buff[i] == 0) {
375 if (buff[i+1] == 0) break;
376 (*arr)[count] = &buff[i+1];
377 CHECK_LE(count, arr_size - 1); // FIXME: make this more flexible.
378 count++;
379 }
380 }
381 (*arr)[count] = 0;
382 }
383 #endif
384
GetArgsAndEnv(char *** argv,char *** envp)385 static void GetArgsAndEnv(char*** argv, char*** envp) {
386 #if !SANITIZER_GO
387 if (&__libc_stack_end) {
388 #endif
389 uptr* stack_end = (uptr*)__libc_stack_end;
390 int argc = *stack_end;
391 *argv = (char**)(stack_end + 1);
392 *envp = (char**)(stack_end + argc + 2);
393 #if !SANITIZER_GO
394 } else {
395 static const int kMaxArgv = 2000, kMaxEnvp = 2000;
396 ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
397 ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
398 }
399 #endif
400 }
401
ReExec()402 void ReExec() {
403 char **argv, **envp;
404 GetArgsAndEnv(&argv, &envp);
405 uptr rv = internal_execve("/proc/self/exe", argv, envp);
406 int rverrno;
407 CHECK_EQ(internal_iserror(rv, &rverrno), true);
408 Printf("execve failed, errno %d\n", rverrno);
409 Die();
410 }
411
412 // Stub implementation of GetThreadStackAndTls for Go.
413 #if SANITIZER_GO
GetThreadStackAndTls(bool main,uptr * stk_addr,uptr * stk_size,uptr * tls_addr,uptr * tls_size)414 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
415 uptr *tls_addr, uptr *tls_size) {
416 *stk_addr = 0;
417 *stk_size = 0;
418 *tls_addr = 0;
419 *tls_size = 0;
420 }
421 #endif // SANITIZER_GO
422
423 enum MutexState {
424 MtxUnlocked = 0,
425 MtxLocked = 1,
426 MtxSleeping = 2
427 };
428
BlockingMutex(LinkerInitialized)429 BlockingMutex::BlockingMutex(LinkerInitialized) {
430 CHECK_EQ(owner_, 0);
431 }
432
BlockingMutex()433 BlockingMutex::BlockingMutex() {
434 internal_memset(this, 0, sizeof(*this));
435 }
436
Lock()437 void BlockingMutex::Lock() {
438 atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
439 if (atomic_exchange(m, MtxLocked, memory_order_acquire) == MtxUnlocked)
440 return;
441 while (atomic_exchange(m, MtxSleeping, memory_order_acquire) != MtxUnlocked) {
442 #if SANITIZER_FREEBSD
443 _umtx_op(m, UMTX_OP_WAIT_UINT, MtxSleeping, 0, 0);
444 #else
445 internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAIT, MtxSleeping, 0, 0, 0);
446 #endif
447 }
448 }
449
Unlock()450 void BlockingMutex::Unlock() {
451 atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
452 u32 v = atomic_exchange(m, MtxUnlocked, memory_order_relaxed);
453 CHECK_NE(v, MtxUnlocked);
454 if (v == MtxSleeping) {
455 #if SANITIZER_FREEBSD
456 _umtx_op(m, UMTX_OP_WAKE, 1, 0, 0);
457 #else
458 internal_syscall(SYSCALL(futex), (uptr)m, FUTEX_WAKE, 1, 0, 0, 0);
459 #endif
460 }
461 }
462
CheckLocked()463 void BlockingMutex::CheckLocked() {
464 atomic_uint32_t *m = reinterpret_cast<atomic_uint32_t *>(&opaque_storage_);
465 CHECK_NE(MtxUnlocked, atomic_load(m, memory_order_relaxed));
466 }
467
468 // ----------------- sanitizer_linux.h
469 // The actual size of this structure is specified by d_reclen.
470 // Note that getdents64 uses a different structure format. We only provide the
471 // 32-bit syscall here.
472 struct linux_dirent {
473 #if SANITIZER_X32
474 u64 d_ino;
475 u64 d_off;
476 #else
477 unsigned long d_ino;
478 unsigned long d_off;
479 #endif
480 unsigned short d_reclen;
481 char d_name[256];
482 };
483
484 // Syscall wrappers.
internal_ptrace(int request,int pid,void * addr,void * data)485 uptr internal_ptrace(int request, int pid, void *addr, void *data) {
486 return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
487 (uptr)data);
488 }
489
internal_waitpid(int pid,int * status,int options)490 uptr internal_waitpid(int pid, int *status, int options) {
491 return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
492 0 /* rusage */);
493 }
494
internal_getpid()495 uptr internal_getpid() {
496 return internal_syscall(SYSCALL(getpid));
497 }
498
internal_getppid()499 uptr internal_getppid() {
500 return internal_syscall(SYSCALL(getppid));
501 }
502
internal_getdents(fd_t fd,struct linux_dirent * dirp,unsigned int count)503 uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
504 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
505 return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
506 #else
507 return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
508 #endif
509 }
510
internal_lseek(fd_t fd,OFF_T offset,int whence)511 uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
512 return internal_syscall(SYSCALL(lseek), fd, offset, whence);
513 }
514
515 #if SANITIZER_LINUX
internal_prctl(int option,uptr arg2,uptr arg3,uptr arg4,uptr arg5)516 uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
517 return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
518 }
519 #endif
520
internal_sigaltstack(const struct sigaltstack * ss,struct sigaltstack * oss)521 uptr internal_sigaltstack(const struct sigaltstack *ss,
522 struct sigaltstack *oss) {
523 return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
524 }
525
internal_fork()526 int internal_fork() {
527 #if SANITIZER_USES_CANONICAL_LINUX_SYSCALLS
528 return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
529 #else
530 return internal_syscall(SYSCALL(fork));
531 #endif
532 }
533
534 #if SANITIZER_LINUX
535 // Doesn't set sa_restorer, use with caution (see below).
internal_sigaction_norestorer(int signum,const void * act,void * oldact)536 int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
537 __sanitizer_kernel_sigaction_t k_act, k_oldact;
538 internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
539 internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
540 const __sanitizer_sigaction *u_act = (__sanitizer_sigaction *)act;
541 __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
542 if (u_act) {
543 k_act.handler = u_act->handler;
544 k_act.sigaction = u_act->sigaction;
545 internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
546 sizeof(__sanitizer_kernel_sigset_t));
547 k_act.sa_flags = u_act->sa_flags;
548 // FIXME: most often sa_restorer is unset, however the kernel requires it
549 // to point to a valid signal restorer that calls the rt_sigreturn syscall.
550 // If sa_restorer passed to the kernel is NULL, the program may crash upon
551 // signal delivery or fail to unwind the stack in the signal handler.
552 // libc implementation of sigaction() passes its own restorer to
553 // rt_sigaction, so we need to do the same (we'll need to reimplement the
554 // restorers; for x86_64 the restorer address can be obtained from
555 // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
556 k_act.sa_restorer = u_act->sa_restorer;
557 }
558
559 uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
560 (uptr)(u_act ? &k_act : NULL),
561 (uptr)(u_oldact ? &k_oldact : NULL),
562 (uptr)sizeof(__sanitizer_kernel_sigset_t));
563
564 if ((result == 0) && u_oldact) {
565 u_oldact->handler = k_oldact.handler;
566 u_oldact->sigaction = k_oldact.sigaction;
567 internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
568 sizeof(__sanitizer_kernel_sigset_t));
569 u_oldact->sa_flags = k_oldact.sa_flags;
570 u_oldact->sa_restorer = k_oldact.sa_restorer;
571 }
572 return result;
573 }
574 #endif // SANITIZER_LINUX
575
internal_sigprocmask(int how,__sanitizer_sigset_t * set,__sanitizer_sigset_t * oldset)576 uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
577 __sanitizer_sigset_t *oldset) {
578 #if SANITIZER_FREEBSD
579 return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
580 #else
581 __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
582 __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
583 return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how,
584 (uptr)&k_set->sig[0], (uptr)&k_oldset->sig[0],
585 sizeof(__sanitizer_kernel_sigset_t));
586 #endif
587 }
588
internal_sigfillset(__sanitizer_sigset_t * set)589 void internal_sigfillset(__sanitizer_sigset_t *set) {
590 internal_memset(set, 0xff, sizeof(*set));
591 }
592
593 #if SANITIZER_LINUX
internal_sigdelset(__sanitizer_sigset_t * set,int signum)594 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
595 signum -= 1;
596 CHECK_GE(signum, 0);
597 CHECK_LT(signum, sizeof(*set) * 8);
598 __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
599 const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
600 const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
601 k_set->sig[idx] &= ~(1 << bit);
602 }
603 #endif // SANITIZER_LINUX
604
605 // ThreadLister implementation.
ThreadLister(int pid)606 ThreadLister::ThreadLister(int pid)
607 : pid_(pid),
608 descriptor_(-1),
609 buffer_(4096),
610 error_(true),
611 entry_((struct linux_dirent *)buffer_.data()),
612 bytes_read_(0) {
613 char task_directory_path[80];
614 internal_snprintf(task_directory_path, sizeof(task_directory_path),
615 "/proc/%d/task/", pid);
616 uptr openrv = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
617 if (internal_iserror(openrv)) {
618 error_ = true;
619 Report("Can't open /proc/%d/task for reading.\n", pid);
620 } else {
621 error_ = false;
622 descriptor_ = openrv;
623 }
624 }
625
GetNextTID()626 int ThreadLister::GetNextTID() {
627 int tid = -1;
628 do {
629 if (error_)
630 return -1;
631 if ((char *)entry_ >= &buffer_[bytes_read_] && !GetDirectoryEntries())
632 return -1;
633 if (entry_->d_ino != 0 && entry_->d_name[0] >= '0' &&
634 entry_->d_name[0] <= '9') {
635 // Found a valid tid.
636 tid = (int)internal_atoll(entry_->d_name);
637 }
638 entry_ = (struct linux_dirent *)(((char *)entry_) + entry_->d_reclen);
639 } while (tid < 0);
640 return tid;
641 }
642
Reset()643 void ThreadLister::Reset() {
644 if (error_ || descriptor_ < 0)
645 return;
646 internal_lseek(descriptor_, 0, SEEK_SET);
647 }
648
~ThreadLister()649 ThreadLister::~ThreadLister() {
650 if (descriptor_ >= 0)
651 internal_close(descriptor_);
652 }
653
error()654 bool ThreadLister::error() { return error_; }
655
GetDirectoryEntries()656 bool ThreadLister::GetDirectoryEntries() {
657 CHECK_GE(descriptor_, 0);
658 CHECK_NE(error_, true);
659 bytes_read_ = internal_getdents(descriptor_,
660 (struct linux_dirent *)buffer_.data(),
661 buffer_.size());
662 if (internal_iserror(bytes_read_)) {
663 Report("Can't read directory entries from /proc/%d/task.\n", pid_);
664 error_ = true;
665 return false;
666 } else if (bytes_read_ == 0) {
667 return false;
668 }
669 entry_ = (struct linux_dirent *)buffer_.data();
670 return true;
671 }
672
GetPageSize()673 uptr GetPageSize() {
674 #if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
675 return EXEC_PAGESIZE;
676 #else
677 return sysconf(_SC_PAGESIZE); // EXEC_PAGESIZE may not be trustworthy.
678 #endif
679 }
680
681 static char proc_self_exe_cache_str[kMaxPathLength];
682 static uptr proc_self_exe_cache_len = 0;
683
ReadBinaryName(char * buf,uptr buf_len)684 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
685 if (proc_self_exe_cache_len > 0) {
686 // If available, use the cached module name.
687 uptr module_name_len =
688 internal_snprintf(buf, buf_len, "%s", proc_self_exe_cache_str);
689 CHECK_LT(module_name_len, buf_len);
690 return module_name_len;
691 }
692 #if SANITIZER_FREEBSD
693 const int Mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1 };
694 size_t Size = buf_len;
695 bool IsErr = (sysctl(Mib, 4, buf, &Size, NULL, 0) != 0);
696 int readlink_error = IsErr ? errno : 0;
697 uptr module_name_len = Size;
698 #else
699 uptr module_name_len = internal_readlink(
700 "/proc/self/exe", buf, buf_len);
701 int readlink_error;
702 bool IsErr = internal_iserror(module_name_len, &readlink_error);
703 #endif
704 if (IsErr) {
705 // We can't read /proc/self/exe for some reason, assume the name of the
706 // binary is unknown.
707 Report("WARNING: readlink(\"/proc/self/exe\") failed with errno %d, "
708 "some stack frames may not be symbolized\n", readlink_error);
709 module_name_len = internal_snprintf(buf, buf_len, "/proc/self/exe");
710 CHECK_LT(module_name_len, buf_len);
711 }
712 return module_name_len;
713 }
714
CacheBinaryName()715 void CacheBinaryName() {
716 if (!proc_self_exe_cache_len) {
717 proc_self_exe_cache_len =
718 ReadBinaryName(proc_self_exe_cache_str, kMaxPathLength);
719 }
720 }
721
722 // Match full names of the form /path/to/base_name{-,.}*
LibraryNameIs(const char * full_name,const char * base_name)723 bool LibraryNameIs(const char *full_name, const char *base_name) {
724 const char *name = full_name;
725 // Strip path.
726 while (*name != '\0') name++;
727 while (name > full_name && *name != '/') name--;
728 if (*name == '/') name++;
729 uptr base_name_length = internal_strlen(base_name);
730 if (internal_strncmp(name, base_name, base_name_length)) return false;
731 return (name[base_name_length] == '-' || name[base_name_length] == '.');
732 }
733
734 #if !SANITIZER_ANDROID
735 // Call cb for each region mapped by map.
ForEachMappedRegion(link_map * map,void (* cb)(const void *,uptr))736 void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
737 #if !SANITIZER_FREEBSD
738 typedef ElfW(Phdr) Elf_Phdr;
739 typedef ElfW(Ehdr) Elf_Ehdr;
740 #endif // !SANITIZER_FREEBSD
741 char *base = (char *)map->l_addr;
742 Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
743 char *phdrs = base + ehdr->e_phoff;
744 char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
745
746 // Find the segment with the minimum base so we can "relocate" the p_vaddr
747 // fields. Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
748 // objects have a non-zero base.
749 uptr preferred_base = (uptr)-1;
750 for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
751 Elf_Phdr *phdr = (Elf_Phdr *)iter;
752 if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
753 preferred_base = (uptr)phdr->p_vaddr;
754 }
755
756 // Compute the delta from the real base to get a relocation delta.
757 sptr delta = (uptr)base - preferred_base;
758 // Now we can figure out what the loader really mapped.
759 for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
760 Elf_Phdr *phdr = (Elf_Phdr *)iter;
761 if (phdr->p_type == PT_LOAD) {
762 uptr seg_start = phdr->p_vaddr + delta;
763 uptr seg_end = seg_start + phdr->p_memsz;
764 // None of these values are aligned. We consider the ragged edges of the
765 // load command as defined, since they are mapped from the file.
766 seg_start = RoundDownTo(seg_start, GetPageSizeCached());
767 seg_end = RoundUpTo(seg_end, GetPageSizeCached());
768 cb((void *)seg_start, seg_end - seg_start);
769 }
770 }
771 }
772 #endif
773
774 #if defined(__x86_64__) && SANITIZER_LINUX
775 // We cannot use glibc's clone wrapper, because it messes with the child
776 // task's TLS. It writes the PID and TID of the child task to its thread
777 // descriptor, but in our case the child task shares the thread descriptor with
778 // the parent (because we don't know how to allocate a new thread
779 // descriptor to keep glibc happy). So the stock version of clone(), when
780 // 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)781 uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
782 int *parent_tidptr, void *newtls, int *child_tidptr) {
783 long long res;
784 if (!fn || !child_stack)
785 return -EINVAL;
786 CHECK_EQ(0, (uptr)child_stack % 16);
787 child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
788 ((unsigned long long *)child_stack)[0] = (uptr)fn;
789 ((unsigned long long *)child_stack)[1] = (uptr)arg;
790 register void *r8 __asm__("r8") = newtls;
791 register int *r10 __asm__("r10") = child_tidptr;
792 __asm__ __volatile__(
793 /* %rax = syscall(%rax = SYSCALL(clone),
794 * %rdi = flags,
795 * %rsi = child_stack,
796 * %rdx = parent_tidptr,
797 * %r8 = new_tls,
798 * %r10 = child_tidptr)
799 */
800 "syscall\n"
801
802 /* if (%rax != 0)
803 * return;
804 */
805 "testq %%rax,%%rax\n"
806 "jnz 1f\n"
807
808 /* In the child. Terminate unwind chain. */
809 // XXX: We should also terminate the CFI unwind chain
810 // here. Unfortunately clang 3.2 doesn't support the
811 // necessary CFI directives, so we skip that part.
812 "xorq %%rbp,%%rbp\n"
813
814 /* Call "fn(arg)". */
815 "popq %%rax\n"
816 "popq %%rdi\n"
817 "call *%%rax\n"
818
819 /* Call _exit(%rax). */
820 "movq %%rax,%%rdi\n"
821 "movq %2,%%rax\n"
822 "syscall\n"
823
824 /* Return to parent. */
825 "1:\n"
826 : "=a" (res)
827 : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
828 "S"(child_stack),
829 "D"(flags),
830 "d"(parent_tidptr),
831 "r"(r8),
832 "r"(r10)
833 : "rsp", "memory", "r11", "rcx");
834 return res;
835 }
836 #endif // defined(__x86_64__) && SANITIZER_LINUX
837
838 #if SANITIZER_ANDROID
839 // This thing is not, strictly speaking, async signal safe, but it does not seem
840 // to cause any issues. Alternative is writing to log devices directly, but
841 // their location and message format might change in the future, so we'd really
842 // like to avoid that.
AndroidLogWrite(const char * buffer)843 void AndroidLogWrite(const char *buffer) {
844 char *copy = internal_strdup(buffer);
845 char *p = copy;
846 char *q;
847 // __android_log_write has an implicit message length limit.
848 // Print one line at a time.
849 do {
850 q = internal_strchr(p, '\n');
851 if (q) *q = '\0';
852 __android_log_write(ANDROID_LOG_INFO, NULL, p);
853 if (q) p = q + 1;
854 } while (q);
855 InternalFree(copy);
856 }
857
GetExtraActivationFlags(char * buf,uptr size)858 void GetExtraActivationFlags(char *buf, uptr size) {
859 CHECK(size > PROP_VALUE_MAX);
860 __system_property_get("asan.options", buf);
861 }
862 #endif
863
IsDeadlySignal(int signum)864 bool IsDeadlySignal(int signum) {
865 return (signum == SIGSEGV) && common_flags()->handle_segv;
866 }
867
868 } // namespace __sanitizer
869
870 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX
871