1//===-- sanitizer_linux.cpp -----------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file is shared between AddressSanitizer and ThreadSanitizer
10// run-time libraries and implements linux-specific functions from
11// sanitizer_libc.h.
12//===----------------------------------------------------------------------===//
13
14#include "sanitizer_platform.h"
15
16#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
17 SANITIZER_SOLARIS
18
19#include "sanitizer_common.h"
20#include "sanitizer_flags.h"
21#include "sanitizer_getauxval.h"
22#include "sanitizer_internal_defs.h"
23#include "sanitizer_libc.h"
24#include "sanitizer_linux.h"
25#include "sanitizer_mutex.h"
26#include "sanitizer_placement_new.h"
27#include "sanitizer_procmaps.h"
28
29#if SANITIZER_LINUX && !SANITIZER_GO
30#include <asm/param.h>
31#endif
32
33// For mips64, syscall(__NR_stat) fills the buffer in the 'struct kernel_stat'
34// format. Struct kernel_stat is defined as 'struct stat' in asm/stat.h. To
35// access stat from asm/stat.h, without conflicting with definition in
36// sys/stat.h, we use this trick.
37#if SANITIZER_MIPS64
38#include <asm/unistd.h>
39#include <sys/types.h>
40#define stat kernel_stat
41#if SANITIZER_GO
42#undef st_atime
43#undef st_mtime
44#undef st_ctime
45#define st_atime st_atim
46#define st_mtime st_mtim
47#define st_ctime st_ctim
48#endif
49#include <asm/stat.h>
50#undef stat
51#endif
52
53#include <dlfcn.h>
54#include <errno.h>
55#include <fcntl.h>
56#include <link.h>
57#include <pthread.h>
58#include <sched.h>
59#include <signal.h>
60#include <sys/mman.h>
61#include <sys/param.h>
62#if !SANITIZER_SOLARIS
63#include <sys/ptrace.h>
64#endif
65#include <sys/resource.h>
66#include <sys/stat.h>
67#include <sys/syscall.h>
68#include <sys/time.h>
69#include <sys/types.h>
70#include <ucontext.h>
71#include <unistd.h>
72
73#if SANITIZER_LINUX
74#include <sys/utsname.h>
75#endif
76
77#if SANITIZER_LINUX && !SANITIZER_ANDROID
78#include <sys/personality.h>
79#endif
80
81#if SANITIZER_LINUX && defined(__loongarch__)
82# include <sys/sysmacros.h>
83#endif
84
85#if SANITIZER_FREEBSD
86#include <sys/exec.h>
87#include <sys/procctl.h>
88#include <sys/sysctl.h>
89#include <machine/atomic.h>
90extern "C" {
91// <sys/umtx.h> must be included after <errno.h> and <sys/types.h> on
92// FreeBSD 9.2 and 10.0.
93#include <sys/umtx.h>
94}
95#include <sys/thr.h>
96#endif // SANITIZER_FREEBSD
97
98#if SANITIZER_NETBSD
99#include <limits.h> // For NAME_MAX
100#include <sys/sysctl.h>
101#include <sys/exec.h>
102extern struct ps_strings *__ps_strings;
103#endif // SANITIZER_NETBSD
104
105#if SANITIZER_SOLARIS
106#include <stdlib.h>
107#include <thread.h>
108#define environ _environ
109#endif
110
111extern char **environ;
112
113#if SANITIZER_LINUX
114// <linux/time.h>
115struct kernel_timeval {
116 long tv_sec;
117 long tv_usec;
118};
119
120// <linux/futex.h> is broken on some linux distributions.
121const int FUTEX_WAIT = 0;
122const int FUTEX_WAKE = 1;
123const int FUTEX_PRIVATE_FLAG = 128;
124const int FUTEX_WAIT_PRIVATE = FUTEX_WAIT | FUTEX_PRIVATE_FLAG;
125const int FUTEX_WAKE_PRIVATE = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
126#endif // SANITIZER_LINUX
127
128// Are we using 32-bit or 64-bit Linux syscalls?
129// x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
130// but it still needs to use 64-bit syscalls.
131#if SANITIZER_LINUX && (defined(__x86_64__) || defined(__powerpc64__) || \
132 SANITIZER_WORDSIZE == 64 || \
133 (defined(__mips__) && _MIPS_SIM == _ABIN32))
134# define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
135#else
136# define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
137#endif
138
139// Note : FreeBSD had implemented both
140// Linux apis, available from
141// future 12.x version most likely
142#if SANITIZER_LINUX && defined(__NR_getrandom)
143# if !defined(GRND_NONBLOCK)
144# define GRND_NONBLOCK 1
145# endif
146# define SANITIZER_USE_GETRANDOM 1
147#else
148# define SANITIZER_USE_GETRANDOM 0
149#endif // SANITIZER_LINUX && defined(__NR_getrandom)
150
151#if SANITIZER_FREEBSD && __FreeBSD_version >= 1200000
152# define SANITIZER_USE_GETENTROPY 1
153#else
154# define SANITIZER_USE_GETENTROPY 0
155#endif
156
157namespace __sanitizer {
158
159void SetSigProcMask(__sanitizer_sigset_t *set, __sanitizer_sigset_t *old) {
160 CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, set, old));
161}
162
163ScopedBlockSignals::ScopedBlockSignals(__sanitizer_sigset_t *copy) {
164 __sanitizer_sigset_t set;
165 internal_sigfillset(&set);
166# if SANITIZER_LINUX && !SANITIZER_ANDROID
167 // Glibc uses SIGSETXID signal during setuid call. If this signal is blocked
168 // on any thread, setuid call hangs.
169 // See test/sanitizer_common/TestCases/Linux/setuid.c.
170 internal_sigdelset(&set, 33);
171# endif
172# if SANITIZER_LINUX
173 // Seccomp-BPF-sandboxed processes rely on SIGSYS to handle trapped syscalls.
174 // If this signal is blocked, such calls cannot be handled and the process may
175 // hang.
176 internal_sigdelset(&set, 31);
177# endif
178 SetSigProcMask(&set, &saved_);
179 if (copy)
180 internal_memcpy(copy, &saved_, sizeof(saved_));
181}
182
183ScopedBlockSignals::~ScopedBlockSignals() { SetSigProcMask(&saved_, nullptr); }
184
185# if SANITIZER_LINUX && defined(__x86_64__)
186# include "sanitizer_syscall_linux_x86_64.inc"
187# elif SANITIZER_LINUX && SANITIZER_RISCV64
188# include "sanitizer_syscall_linux_riscv64.inc"
189# elif SANITIZER_LINUX && defined(__aarch64__)
190# include "sanitizer_syscall_linux_aarch64.inc"
191# elif SANITIZER_LINUX && defined(__arm__)
192# include "sanitizer_syscall_linux_arm.inc"
193# elif SANITIZER_LINUX && defined(__hexagon__)
194# include "sanitizer_syscall_linux_hexagon.inc"
195# elif SANITIZER_LINUX && SANITIZER_LOONGARCH64
196# include "sanitizer_syscall_linux_loongarch64.inc"
197# else
198# include "sanitizer_syscall_generic.inc"
199# endif
200
201// --------------- sanitizer_libc.h
202#if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
203#if !SANITIZER_S390
204uptr internal_mmap(void *addr, uptr length, int prot, int flags, int fd,
205 u64 offset) {
206#if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
207 return internal_syscall(SYSCALL(mmap), (uptr)addr, length, prot, flags, fd,
208 offset);
209#else
210 // mmap2 specifies file offset in 4096-byte units.
211 CHECK(IsAligned(offset, 4096));
212 return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
213 offset / 4096);
214#endif
215}
216#endif // !SANITIZER_S390
217
218uptr internal_munmap(void *addr, uptr length) {
219 return internal_syscall(SYSCALL(munmap), (uptr)addr, length);
220}
221
222#if SANITIZER_LINUX
223uptr internal_mremap(void *old_address, uptr old_size, uptr new_size, int flags,
224 void *new_address) {
225 return internal_syscall(SYSCALL(mremap), (uptr)old_address, old_size,
226 new_size, flags, (uptr)new_address);
227}
228#endif
229
230int internal_mprotect(void *addr, uptr length, int prot) {
231 return internal_syscall(SYSCALL(mprotect), (uptr)addr, length, prot);
232}
233
234int internal_madvise(uptr addr, uptr length, int advice) {
235 return internal_syscall(SYSCALL(madvise), addr, length, advice);
236}
237
238uptr internal_close(fd_t fd) {
239 return internal_syscall(SYSCALL(close), fd);
240}
241
242uptr internal_open(const char *filename, int flags) {
243# if SANITIZER_LINUX
244 return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags);
245#else
246 return internal_syscall(SYSCALL(open), (uptr)filename, flags);
247#endif
248}
249
250uptr internal_open(const char *filename, int flags, u32 mode) {
251# if SANITIZER_LINUX
252 return internal_syscall(SYSCALL(openat), AT_FDCWD, (uptr)filename, flags,
253 mode);
254#else
255 return internal_syscall(SYSCALL(open), (uptr)filename, flags, mode);
256#endif
257}
258
259uptr internal_read(fd_t fd, void *buf, uptr count) {
260 sptr res;
261 HANDLE_EINTR(res,
262 (sptr)internal_syscall(SYSCALL(read), fd, (uptr)buf, count));
263 return res;
264}
265
266uptr internal_write(fd_t fd, const void *buf, uptr count) {
267 sptr res;
268 HANDLE_EINTR(res,
269 (sptr)internal_syscall(SYSCALL(write), fd, (uptr)buf, count));
270 return res;
271}
272
273uptr internal_ftruncate(fd_t fd, uptr size) {
274 sptr res;
275 HANDLE_EINTR(res, (sptr)internal_syscall(SYSCALL(ftruncate), fd,
276 (OFF_T)size));
277 return res;
278}
279
280#if (!SANITIZER_LINUX_USES_64BIT_SYSCALLS || SANITIZER_SPARC) && SANITIZER_LINUX
281static void stat64_to_stat(struct stat64 *in, struct stat *out) {
282 internal_memset(out, 0, sizeof(*out));
283 out->st_dev = in->st_dev;
284 out->st_ino = in->st_ino;
285 out->st_mode = in->st_mode;
286 out->st_nlink = in->st_nlink;
287 out->st_uid = in->st_uid;
288 out->st_gid = in->st_gid;
289 out->st_rdev = in->st_rdev;
290 out->st_size = in->st_size;
291 out->st_blksize = in->st_blksize;
292 out->st_blocks = in->st_blocks;
293 out->st_atime = in->st_atime;
294 out->st_mtime = in->st_mtime;
295 out->st_ctime = in->st_ctime;
296}
297#endif
298
299#if SANITIZER_LINUX && defined(__loongarch__)
300static void statx_to_stat(struct statx *in, struct stat *out) {
301 internal_memset(out, 0, sizeof(*out));
302 out->st_dev = makedev(in->stx_dev_major, in->stx_dev_minor);
303 out->st_ino = in->stx_ino;
304 out->st_mode = in->stx_mode;
305 out->st_nlink = in->stx_nlink;
306 out->st_uid = in->stx_uid;
307 out->st_gid = in->stx_gid;
308 out->st_rdev = makedev(in->stx_rdev_major, in->stx_rdev_minor);
309 out->st_size = in->stx_size;
310 out->st_blksize = in->stx_blksize;
311 out->st_blocks = in->stx_blocks;
312 out->st_atime = in->stx_atime.tv_sec;
313 out->st_atim.tv_nsec = in->stx_atime.tv_nsec;
314 out->st_mtime = in->stx_mtime.tv_sec;
315 out->st_mtim.tv_nsec = in->stx_mtime.tv_nsec;
316 out->st_ctime = in->stx_ctime.tv_sec;
317 out->st_ctim.tv_nsec = in->stx_ctime.tv_nsec;
318}
319#endif
320
321#if SANITIZER_MIPS64
322// Undefine compatibility macros from <sys/stat.h>
323// so that they would not clash with the kernel_stat
324// st_[a|m|c]time fields
325#if !SANITIZER_GO
326#undef st_atime
327#undef st_mtime
328#undef st_ctime
329#endif
330#if defined(SANITIZER_ANDROID)
331// Bionic sys/stat.h defines additional macros
332// for compatibility with the old NDKs and
333// they clash with the kernel_stat structure
334// st_[a|m|c]time_nsec fields.
335#undef st_atime_nsec
336#undef st_mtime_nsec
337#undef st_ctime_nsec
338#endif
339static void kernel_stat_to_stat(struct kernel_stat *in, struct stat *out) {
340 internal_memset(out, 0, sizeof(*out));
341 out->st_dev = in->st_dev;
342 out->st_ino = in->st_ino;
343 out->st_mode = in->st_mode;
344 out->st_nlink = in->st_nlink;
345 out->st_uid = in->st_uid;
346 out->st_gid = in->st_gid;
347 out->st_rdev = in->st_rdev;
348 out->st_size = in->st_size;
349 out->st_blksize = in->st_blksize;
350 out->st_blocks = in->st_blocks;
351#if defined(__USE_MISC) || \
352 defined(__USE_XOPEN2K8) || \
353 defined(SANITIZER_ANDROID)
354 out->st_atim.tv_sec = in->st_atime;
355 out->st_atim.tv_nsec = in->st_atime_nsec;
356 out->st_mtim.tv_sec = in->st_mtime;
357 out->st_mtim.tv_nsec = in->st_mtime_nsec;
358 out->st_ctim.tv_sec = in->st_ctime;
359 out->st_ctim.tv_nsec = in->st_ctime_nsec;
360#else
361 out->st_atime = in->st_atime;
362 out->st_atimensec = in->st_atime_nsec;
363 out->st_mtime = in->st_mtime;
364 out->st_mtimensec = in->st_mtime_nsec;
365 out->st_ctime = in->st_ctime;
366 out->st_atimensec = in->st_ctime_nsec;
367#endif
368}
369#endif
370
371uptr internal_stat(const char *path, void *buf) {
372# if SANITIZER_FREEBSD
373 return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf, 0);
374# elif SANITIZER_LINUX
375# if defined(__loongarch__)
376 struct statx bufx;
377 int res = internal_syscall(SYSCALL(statx), AT_FDCWD, (uptr)path,
378 AT_NO_AUTOMOUNT, STATX_BASIC_STATS, (uptr)&bufx);
379 statx_to_stat(&bufx, (struct stat *)buf);
380 return res;
381# elif (SANITIZER_WORDSIZE == 64 || SANITIZER_X32 || \
382 (defined(__mips__) && _MIPS_SIM == _ABIN32)) && \
383 !SANITIZER_SPARC
384 return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
385 0);
386# else
387 struct stat64 buf64;
388 int res = internal_syscall(SYSCALL(fstatat64), AT_FDCWD, (uptr)path,
389 (uptr)&buf64, 0);
390 stat64_to_stat(&buf64, (struct stat *)buf);
391 return res;
392# endif
393# else
394 struct stat64 buf64;
395 int res = internal_syscall(SYSCALL(stat64), path, &buf64);
396 stat64_to_stat(&buf64, (struct stat *)buf);
397 return res;
398# endif
399}
400
401uptr internal_lstat(const char *path, void *buf) {
402# if SANITIZER_FREEBSD
403 return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf,
404 AT_SYMLINK_NOFOLLOW);
405# elif SANITIZER_LINUX
406# if defined(__loongarch__)
407 struct statx bufx;
408 int res = internal_syscall(SYSCALL(statx), AT_FDCWD, (uptr)path,
409 AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT,
410 STATX_BASIC_STATS, (uptr)&bufx);
411 statx_to_stat(&bufx, (struct stat *)buf);
412 return res;
413# elif (defined(_LP64) || SANITIZER_X32 || \
414 (defined(__mips__) && _MIPS_SIM == _ABIN32)) && \
415 !SANITIZER_SPARC
416 return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
417 AT_SYMLINK_NOFOLLOW);
418# else
419 struct stat64 buf64;
420 int res = internal_syscall(SYSCALL(fstatat64), AT_FDCWD, (uptr)path,
421 (uptr)&buf64, AT_SYMLINK_NOFOLLOW);
422 stat64_to_stat(&buf64, (struct stat *)buf);
423 return res;
424# endif
425# else
426 struct stat64 buf64;
427 int res = internal_syscall(SYSCALL(lstat64), path, &buf64);
428 stat64_to_stat(&buf64, (struct stat *)buf);
429 return res;
430# endif
431}
432
433uptr internal_fstat(fd_t fd, void *buf) {
434#if SANITIZER_FREEBSD || SANITIZER_LINUX_USES_64BIT_SYSCALLS
435#if SANITIZER_MIPS64
436 // For mips64, fstat syscall fills buffer in the format of kernel_stat
437 struct kernel_stat kbuf;
438 int res = internal_syscall(SYSCALL(fstat), fd, &kbuf);
439 kernel_stat_to_stat(&kbuf, (struct stat *)buf);
440 return res;
441# elif SANITIZER_LINUX && defined(__loongarch__)
442 struct statx bufx;
443 int res = internal_syscall(SYSCALL(statx), fd, 0, AT_EMPTY_PATH,
444 STATX_BASIC_STATS, (uptr)&bufx);
445 statx_to_stat(&bufx, (struct stat *)buf);
446 return res;
447# else
448 return internal_syscall(SYSCALL(fstat), fd, (uptr)buf);
449# endif
450#else
451 struct stat64 buf64;
452 int res = internal_syscall(SYSCALL(fstat64), fd, &buf64);
453 stat64_to_stat(&buf64, (struct stat *)buf);
454 return res;
455#endif
456}
457
458uptr internal_filesize(fd_t fd) {
459 struct stat st;
460 if (internal_fstat(fd, &st))
461 return -1;
462 return (uptr)st.st_size;
463}
464
465uptr internal_dup(int oldfd) {
466 return internal_syscall(SYSCALL(dup), oldfd);
467}
468
469uptr internal_dup2(int oldfd, int newfd) {
470# if SANITIZER_LINUX
471 return internal_syscall(SYSCALL(dup3), oldfd, newfd, 0);
472#else
473 return internal_syscall(SYSCALL(dup2), oldfd, newfd);
474#endif
475}
476
477uptr internal_readlink(const char *path, char *buf, uptr bufsize) {
478# if SANITIZER_LINUX
479 return internal_syscall(SYSCALL(readlinkat), AT_FDCWD, (uptr)path, (uptr)buf,
480 bufsize);
481#else
482 return internal_syscall(SYSCALL(readlink), (uptr)path, (uptr)buf, bufsize);
483#endif
484}
485
486uptr internal_unlink(const char *path) {
487# if SANITIZER_LINUX
488 return internal_syscall(SYSCALL(unlinkat), AT_FDCWD, (uptr)path, 0);
489#else
490 return internal_syscall(SYSCALL(unlink), (uptr)path);
491#endif
492}
493
494uptr internal_rename(const char *oldpath, const char *newpath) {
495# if (defined(__riscv) || defined(__loongarch__)) && defined(__linux__)
496 return internal_syscall(SYSCALL(renameat2), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
497 (uptr)newpath, 0);
498# elif SANITIZER_LINUX
499 return internal_syscall(SYSCALL(renameat), AT_FDCWD, (uptr)oldpath, AT_FDCWD,
500 (uptr)newpath);
501# else
502 return internal_syscall(SYSCALL(rename), (uptr)oldpath, (uptr)newpath);
503# endif
504}
505
506uptr internal_sched_yield() {
507 return internal_syscall(SYSCALL(sched_yield));
508}
509
510void internal_usleep(u64 useconds) {
511 struct timespec ts;
512 ts.tv_sec = useconds / 1000000;
513 ts.tv_nsec = (useconds % 1000000) * 1000;
514 internal_syscall(SYSCALL(nanosleep), &ts, &ts);
515}
516
517uptr internal_execve(const char *filename, char *const argv[],
518 char *const envp[]) {
519 return internal_syscall(SYSCALL(execve), (uptr)filename, (uptr)argv,
520 (uptr)envp);
521}
522#endif // !SANITIZER_SOLARIS && !SANITIZER_NETBSD
523
524#if !SANITIZER_NETBSD
525void internal__exit(int exitcode) {
526#if SANITIZER_FREEBSD || SANITIZER_SOLARIS
527 internal_syscall(SYSCALL(exit), exitcode);
528#else
529 internal_syscall(SYSCALL(exit_group), exitcode);
530#endif
531 Die(); // Unreachable.
532}
533#endif // !SANITIZER_NETBSD
534
535// ----------------- sanitizer_common.h
536bool FileExists(const char *filename) {
537 if (ShouldMockFailureToOpen(filename))
538 return false;
539 struct stat st;
540 if (internal_stat(filename, &st))
541 return false;
542 // Sanity check: filename is a regular file.
543 return S_ISREG(st.st_mode);
544}
545
546bool DirExists(const char *path) {
547 struct stat st;
548 if (internal_stat(path, &st))
549 return false;
550 return S_ISDIR(st.st_mode);
551}
552
553# if !SANITIZER_NETBSD
554tid_t GetTid() {
555#if SANITIZER_FREEBSD
556 long Tid;
557 thr_self(&Tid);
558 return Tid;
559#elif SANITIZER_SOLARIS
560 return thr_self();
561#else
562 return internal_syscall(SYSCALL(gettid));
563#endif
564}
565
566int TgKill(pid_t pid, tid_t tid, int sig) {
567#if SANITIZER_LINUX
568 return internal_syscall(SYSCALL(tgkill), pid, tid, sig);
569#elif SANITIZER_FREEBSD
570 return internal_syscall(SYSCALL(thr_kill2), pid, tid, sig);
571#elif SANITIZER_SOLARIS
572 (void)pid;
573 return thr_kill(tid, sig);
574#endif
575}
576#endif
577
578#if SANITIZER_GLIBC
579u64 NanoTime() {
580 kernel_timeval tv;
581 internal_memset(&tv, 0, sizeof(tv));
582 internal_syscall(SYSCALL(gettimeofday), &tv, 0);
583 return (u64)tv.tv_sec * 1000 * 1000 * 1000 + tv.tv_usec * 1000;
584}
585// Used by real_clock_gettime.
586uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp) {
587 return internal_syscall(SYSCALL(clock_gettime), clk_id, tp);
588}
589#elif !SANITIZER_SOLARIS && !SANITIZER_NETBSD
590u64 NanoTime() {
591 struct timespec ts;
592 clock_gettime(CLOCK_REALTIME, &ts);
593 return (u64)ts.tv_sec * 1000 * 1000 * 1000 + ts.tv_nsec;
594}
595#endif
596
597// Like getenv, but reads env directly from /proc (on Linux) or parses the
598// 'environ' array (on some others) and does not use libc. This function
599// should be called first inside __asan_init.
600const char *GetEnv(const char *name) {
601#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_SOLARIS
602 if (::environ != 0) {
603 uptr NameLen = internal_strlen(name);
604 for (char **Env = ::environ; *Env != 0; Env++) {
605 if (internal_strncmp(*Env, name, NameLen) == 0 && (*Env)[NameLen] == '=')
606 return (*Env) + NameLen + 1;
607 }
608 }
609 return 0; // Not found.
610#elif SANITIZER_LINUX
611 static char *environ;
612 static uptr len;
613 static bool inited;
614 if (!inited) {
615 inited = true;
616 uptr environ_size;
617 if (!ReadFileToBuffer("/proc/self/environ", &environ, &environ_size, &len))
618 environ = nullptr;
619 }
620 if (!environ || len == 0) return nullptr;
621 uptr namelen = internal_strlen(name);
622 const char *p = environ;
623 while (*p != '\0') { // will happen at the \0\0 that terminates the buffer
624 // proc file has the format NAME=value\0NAME=value\0NAME=value\0...
625 const char* endp =
626 (char*)internal_memchr(p, '\0', len - (p - environ));
627 if (!endp) // this entry isn't NUL terminated
628 return nullptr;
629 else if (!internal_memcmp(p, name, namelen) && p[namelen] == '=') // Match.
630 return p + namelen + 1; // point after =
631 p = endp + 1;
632 }
633 return nullptr; // Not found.
634#else
635#error "Unsupported platform"
636#endif
637}
638
639#if !SANITIZER_FREEBSD && !SANITIZER_NETBSD && !SANITIZER_GO
640extern "C" {
641SANITIZER_WEAK_ATTRIBUTE extern void *__libc_stack_end;
642}
643#endif
644
645#if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
646static void ReadNullSepFileToArray(const char *path, char ***arr,
647 int arr_size) {
648 char *buff;
649 uptr buff_size;
650 uptr buff_len;
651 *arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
652 if (!ReadFileToBuffer(path, &buff, &buff_size, &buff_len, 1024 * 1024)) {
653 (*arr)[0] = nullptr;
654 return;
655 }
656 (*arr)[0] = buff;
657 int count, i;
658 for (count = 1, i = 1; ; i++) {
659 if (buff[i] == 0) {
660 if (buff[i+1] == 0) break;
661 (*arr)[count] = &buff[i+1];
662 CHECK_LE(count, arr_size - 1); // FIXME: make this more flexible.
663 count++;
664 }
665 }
666 (*arr)[count] = nullptr;
667}
668#endif
669
670static void GetArgsAndEnv(char ***argv, char ***envp) {
671#if SANITIZER_FREEBSD
672 // On FreeBSD, retrieving the argument and environment arrays is done via the
673 // kern.ps_strings sysctl, which returns a pointer to a structure containing
674 // this information. See also <sys/exec.h>.
675 ps_strings *pss;
676 uptr sz = sizeof(pss);
677 if (internal_sysctlbyname("kern.ps_strings", &pss, &sz, NULL, 0) == -1) {
678 Printf("sysctl kern.ps_strings failed\n");
679 Die();
680 }
681 *argv = pss->ps_argvstr;
682 *envp = pss->ps_envstr;
683#elif SANITIZER_NETBSD
684 *argv = __ps_strings->ps_argvstr;
685 *envp = __ps_strings->ps_envstr;
686#else // SANITIZER_FREEBSD
687#if !SANITIZER_GO
688 if (&__libc_stack_end) {
689 uptr* stack_end = (uptr*)__libc_stack_end;
690 // Normally argc can be obtained from *stack_end, however, on ARM glibc's
691 // _start clobbers it:
692 // https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/arm/start.S;hb=refs/heads/release/2.31/master#l75
693 // Do not special-case ARM and infer argc from argv everywhere.
694 int argc = 0;
695 while (stack_end[argc + 1]) argc++;
696 *argv = (char**)(stack_end + 1);
697 *envp = (char**)(stack_end + argc + 2);
698 } else {
699#endif // !SANITIZER_GO
700 static const int kMaxArgv = 2000, kMaxEnvp = 2000;
701 ReadNullSepFileToArray("/proc/self/cmdline", argv, kMaxArgv);
702 ReadNullSepFileToArray("/proc/self/environ", envp, kMaxEnvp);
703#if !SANITIZER_GO
704 }
705#endif // !SANITIZER_GO
706#endif // SANITIZER_FREEBSD
707}
708
709char **GetArgv() {
710 char **argv, **envp;
711 GetArgsAndEnv(&argv, &envp);
712 return argv;
713}
714
715char **GetEnviron() {
716 char **argv, **envp;
717 GetArgsAndEnv(&argv, &envp);
718 return envp;
719}
720
721#if !SANITIZER_SOLARIS
722void FutexWait(atomic_uint32_t *p, u32 cmp) {
723# if SANITIZER_FREEBSD
724 _umtx_op(p, UMTX_OP_WAIT_UINT, cmp, 0, 0);
725# elif SANITIZER_NETBSD
726 sched_yield(); /* No userspace futex-like synchronization */
727# else
728 internal_syscall(SYSCALL(futex), (uptr)p, FUTEX_WAIT_PRIVATE, cmp, 0, 0, 0);
729# endif
730}
731
732void FutexWake(atomic_uint32_t *p, u32 count) {
733# if SANITIZER_FREEBSD
734 _umtx_op(p, UMTX_OP_WAKE, count, 0, 0);
735# elif SANITIZER_NETBSD
736 /* No userspace futex-like synchronization */
737# else
738 internal_syscall(SYSCALL(futex), (uptr)p, FUTEX_WAKE_PRIVATE, count, 0, 0, 0);
739# endif
740}
741
742# endif // !SANITIZER_SOLARIS
743
744// ----------------- sanitizer_linux.h
745// The actual size of this structure is specified by d_reclen.
746// Note that getdents64 uses a different structure format. We only provide the
747// 32-bit syscall here.
748#if SANITIZER_NETBSD
749// Not used
750#else
751struct linux_dirent {
752# if SANITIZER_X32 || SANITIZER_LINUX
753 u64 d_ino;
754 u64 d_off;
755# else
756 unsigned long d_ino;
757 unsigned long d_off;
758# endif
759 unsigned short d_reclen;
760# if SANITIZER_LINUX
761 unsigned char d_type;
762# endif
763 char d_name[256];
764};
765#endif
766
767#if !SANITIZER_SOLARIS && !SANITIZER_NETBSD
768// Syscall wrappers.
769uptr internal_ptrace(int request, int pid, void *addr, void *data) {
770 return internal_syscall(SYSCALL(ptrace), request, pid, (uptr)addr,
771 (uptr)data);
772}
773
774uptr internal_waitpid(int pid, int *status, int options) {
775 return internal_syscall(SYSCALL(wait4), pid, (uptr)status, options,
776 0 /* rusage */);
777}
778
779uptr internal_getpid() {
780 return internal_syscall(SYSCALL(getpid));
781}
782
783uptr internal_getppid() {
784 return internal_syscall(SYSCALL(getppid));
785}
786
787int internal_dlinfo(void *handle, int request, void *p) {
788#if SANITIZER_FREEBSD
789 return dlinfo(handle, request, p);
790#else
791 UNIMPLEMENTED();
792#endif
793}
794
795uptr internal_getdents(fd_t fd, struct linux_dirent *dirp, unsigned int count) {
796#if SANITIZER_FREEBSD
797 return internal_syscall(SYSCALL(getdirentries), fd, (uptr)dirp, count, NULL);
798# elif SANITIZER_LINUX
799 return internal_syscall(SYSCALL(getdents64), fd, (uptr)dirp, count);
800# else
801 return internal_syscall(SYSCALL(getdents), fd, (uptr)dirp, count);
802# endif
803}
804
805uptr internal_lseek(fd_t fd, OFF_T offset, int whence) {
806 return internal_syscall(SYSCALL(lseek), fd, offset, whence);
807}
808
809#if SANITIZER_LINUX
810uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5) {
811 return internal_syscall(SYSCALL(prctl), option, arg2, arg3, arg4, arg5);
812}
813# if defined(__x86_64__)
814# include <asm/unistd_64.h>
815// Currently internal_arch_prctl() is only needed on x86_64.
816uptr internal_arch_prctl(int option, uptr arg2) {
817 return internal_syscall(__NR_arch_prctl, option, arg2);
818}
819# endif
820# endif
821
822uptr internal_sigaltstack(const void *ss, void *oss) {
823 return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
824}
825
826int internal_fork() {
827# if SANITIZER_LINUX
828# if SANITIZER_S390
829 return internal_syscall(SYSCALL(clone), 0, SIGCHLD);
830# else
831 return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
832# endif
833# else
834 return internal_syscall(SYSCALL(fork));
835# endif
836}
837
838#if SANITIZER_FREEBSD
839int internal_sysctl(const int *name, unsigned int namelen, void *oldp,
840 uptr *oldlenp, const void *newp, uptr newlen) {
841 return internal_syscall(SYSCALL(__sysctl), name, namelen, oldp,
842 (size_t *)oldlenp, newp, (size_t)newlen);
843}
844
845int internal_sysctlbyname(const char *sname, void *oldp, uptr *oldlenp,
846 const void *newp, uptr newlen) {
847 // Note: this function can be called during startup, so we need to avoid
848 // calling any interceptable functions. On FreeBSD >= 1300045 sysctlbyname()
849 // is a real syscall, but for older versions it calls sysctlnametomib()
850 // followed by sysctl(). To avoid calling the intercepted version and
851 // asserting if this happens during startup, call the real sysctlnametomib()
852 // followed by internal_sysctl() if the syscall is not available.
853#ifdef SYS___sysctlbyname
854 return internal_syscall(SYSCALL(__sysctlbyname), sname,
855 internal_strlen(sname), oldp, (size_t *)oldlenp, newp,
856 (size_t)newlen);
857#else
858 static decltype(sysctlnametomib) *real_sysctlnametomib = nullptr;
859 if (!real_sysctlnametomib)
860 real_sysctlnametomib =
861 (decltype(sysctlnametomib) *)dlsym(RTLD_NEXT, "sysctlnametomib");
862 CHECK(real_sysctlnametomib);
863
864 int oid[CTL_MAXNAME];
865 size_t len = CTL_MAXNAME;
866 if (real_sysctlnametomib(sname, oid, &len) == -1)
867 return (-1);
868 return internal_sysctl(oid, len, oldp, oldlenp, newp, newlen);
869#endif
870}
871#endif
872
873#if SANITIZER_LINUX
874#define SA_RESTORER 0x04000000
875// Doesn't set sa_restorer if the caller did not set it, so use with caution
876//(see below).
877int internal_sigaction_norestorer(int signum, const void *act, void *oldact) {
878 __sanitizer_kernel_sigaction_t k_act, k_oldact;
879 internal_memset(&k_act, 0, sizeof(__sanitizer_kernel_sigaction_t));
880 internal_memset(&k_oldact, 0, sizeof(__sanitizer_kernel_sigaction_t));
881 const __sanitizer_sigaction *u_act = (const __sanitizer_sigaction *)act;
882 __sanitizer_sigaction *u_oldact = (__sanitizer_sigaction *)oldact;
883 if (u_act) {
884 k_act.handler = u_act->handler;
885 k_act.sigaction = u_act->sigaction;
886 internal_memcpy(&k_act.sa_mask, &u_act->sa_mask,
887 sizeof(__sanitizer_kernel_sigset_t));
888 // Without SA_RESTORER kernel ignores the calls (probably returns EINVAL).
889 k_act.sa_flags = u_act->sa_flags | SA_RESTORER;
890 // FIXME: most often sa_restorer is unset, however the kernel requires it
891 // to point to a valid signal restorer that calls the rt_sigreturn syscall.
892 // If sa_restorer passed to the kernel is NULL, the program may crash upon
893 // signal delivery or fail to unwind the stack in the signal handler.
894 // libc implementation of sigaction() passes its own restorer to
895 // rt_sigaction, so we need to do the same (we'll need to reimplement the
896 // restorers; for x86_64 the restorer address can be obtained from
897 // oldact->sa_restorer upon a call to sigaction(xxx, NULL, oldact).
898#if !SANITIZER_ANDROID || !SANITIZER_MIPS32
899 k_act.sa_restorer = u_act->sa_restorer;
900#endif
901 }
902
903 uptr result = internal_syscall(SYSCALL(rt_sigaction), (uptr)signum,
904 (uptr)(u_act ? &k_act : nullptr),
905 (uptr)(u_oldact ? &k_oldact : nullptr),
906 (uptr)sizeof(__sanitizer_kernel_sigset_t));
907
908 if ((result == 0) && u_oldact) {
909 u_oldact->handler = k_oldact.handler;
910 u_oldact->sigaction = k_oldact.sigaction;
911 internal_memcpy(&u_oldact->sa_mask, &k_oldact.sa_mask,
912 sizeof(__sanitizer_kernel_sigset_t));
913 u_oldact->sa_flags = k_oldact.sa_flags;
914#if !SANITIZER_ANDROID || !SANITIZER_MIPS32
915 u_oldact->sa_restorer = k_oldact.sa_restorer;
916#endif
917 }
918 return result;
919}
920#endif // SANITIZER_LINUX
921
922uptr internal_sigprocmask(int how, __sanitizer_sigset_t *set,
923 __sanitizer_sigset_t *oldset) {
924#if SANITIZER_FREEBSD
925 return internal_syscall(SYSCALL(sigprocmask), how, set, oldset);
926#else
927 __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
928 __sanitizer_kernel_sigset_t *k_oldset = (__sanitizer_kernel_sigset_t *)oldset;
929 return internal_syscall(SYSCALL(rt_sigprocmask), (uptr)how, (uptr)k_set,
930 (uptr)k_oldset, sizeof(__sanitizer_kernel_sigset_t));
931#endif
932}
933
934void internal_sigfillset(__sanitizer_sigset_t *set) {
935 internal_memset(set, 0xff, sizeof(*set));
936}
937
938void internal_sigemptyset(__sanitizer_sigset_t *set) {
939 internal_memset(set, 0, sizeof(*set));
940}
941
942#if SANITIZER_LINUX
943void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
944 signum -= 1;
945 CHECK_GE(signum, 0);
946 CHECK_LT(signum, sizeof(*set) * 8);
947 __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
948 const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
949 const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
950 k_set->sig[idx] &= ~((uptr)1 << bit);
951}
952
953bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
954 signum -= 1;
955 CHECK_GE(signum, 0);
956 CHECK_LT(signum, sizeof(*set) * 8);
957 __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
958 const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
959 const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
960 return k_set->sig[idx] & ((uptr)1 << bit);
961}
962#elif SANITIZER_FREEBSD
963uptr internal_procctl(int type, int id, int cmd, void *data) {
964 return internal_syscall(SYSCALL(procctl), type, id, cmd, data);
965}
966
967void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
968 sigset_t *rset = reinterpret_cast<sigset_t *>(set);
969 sigdelset(rset, signum);
970}
971
972bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
973 sigset_t *rset = reinterpret_cast<sigset_t *>(set);
974 return sigismember(rset, signum);
975}
976#endif
977#endif // !SANITIZER_SOLARIS
978
979#if !SANITIZER_NETBSD
980// ThreadLister implementation.
981ThreadLister::ThreadLister(pid_t pid) : pid_(pid), buffer_(4096) {
982 char task_directory_path[80];
983 internal_snprintf(task_directory_path, sizeof(task_directory_path),
984 "/proc/%d/task/", pid);
985 descriptor_ = internal_open(task_directory_path, O_RDONLY | O_DIRECTORY);
986 if (internal_iserror(descriptor_)) {
987 Report("Can't open /proc/%d/task for reading.\n", pid);
988 }
989}
990
991ThreadLister::Result ThreadLister::ListThreads(
992 InternalMmapVector<tid_t> *threads) {
993 if (internal_iserror(descriptor_))
994 return Error;
995 internal_lseek(descriptor_, 0, SEEK_SET);
996 threads->clear();
997
998 Result result = Ok;
999 for (bool first_read = true;; first_read = false) {
1000 // Resize to max capacity if it was downsized by IsAlive.
1001 buffer_.resize(buffer_.capacity());
1002 CHECK_GE(buffer_.size(), 4096);
1003 uptr read = internal_getdents(
1004 descriptor_, (struct linux_dirent *)buffer_.data(), buffer_.size());
1005 if (!read)
1006 return result;
1007 if (internal_iserror(read)) {
1008 Report("Can't read directory entries from /proc/%d/task.\n", pid_);
1009 return Error;
1010 }
1011
1012 for (uptr begin = (uptr)buffer_.data(), end = begin + read; begin < end;) {
1013 struct linux_dirent *entry = (struct linux_dirent *)begin;
1014 begin += entry->d_reclen;
1015 if (entry->d_ino == 1) {
1016 // Inode 1 is for bad blocks and also can be a reason for early return.
1017 // Should be emitted if kernel tried to output terminating thread.
1018 // See proc_task_readdir implementation in Linux.
1019 result = Incomplete;
1020 }
1021 if (entry->d_ino && *entry->d_name >= '0' && *entry->d_name <= '9')
1022 threads->push_back(internal_atoll(entry->d_name));
1023 }
1024
1025 // Now we are going to detect short-read or early EOF. In such cases Linux
1026 // can return inconsistent list with missing alive threads.
1027 // Code will just remember that the list can be incomplete but it will
1028 // continue reads to return as much as possible.
1029 if (!first_read) {
1030 // The first one was a short-read by definition.
1031 result = Incomplete;
1032 } else if (read > buffer_.size() - 1024) {
1033 // Read was close to the buffer size. So double the size and assume the
1034 // worst.
1035 buffer_.resize(buffer_.size() * 2);
1036 result = Incomplete;
1037 } else if (!threads->empty() && !IsAlive(threads->back())) {
1038 // Maybe Linux early returned from read on terminated thread (!pid_alive)
1039 // and failed to restore read position.
1040 // See next_tid and proc_task_instantiate in Linux.
1041 result = Incomplete;
1042 }
1043 }
1044}
1045
1046bool ThreadLister::IsAlive(int tid) {
1047 // /proc/%d/task/%d/status uses same call to detect alive threads as
1048 // proc_task_readdir. See task_state implementation in Linux.
1049 char path[80];
1050 internal_snprintf(path, sizeof(path), "/proc/%d/task/%d/status", pid_, tid);
1051 if (!ReadFileToVector(path, &buffer_) || buffer_.empty())
1052 return false;
1053 buffer_.push_back(0);
1054 static const char kPrefix[] = "\nPPid:";
1055 const char *field = internal_strstr(buffer_.data(), kPrefix);
1056 if (!field)
1057 return false;
1058 field += internal_strlen(kPrefix);
1059 return (int)internal_atoll(field) != 0;
1060}
1061
1062ThreadLister::~ThreadLister() {
1063 if (!internal_iserror(descriptor_))
1064 internal_close(descriptor_);
1065}
1066#endif
1067
1068#if SANITIZER_WORDSIZE == 32
1069// Take care of unusable kernel area in top gigabyte.
1070static uptr GetKernelAreaSize() {
1071#if SANITIZER_LINUX && !SANITIZER_X32
1072 const uptr gbyte = 1UL << 30;
1073
1074 // Firstly check if there are writable segments
1075 // mapped to top gigabyte (e.g. stack).
1076 MemoryMappingLayout proc_maps(/*cache_enabled*/true);
1077 if (proc_maps.Error())
1078 return 0;
1079 MemoryMappedSegment segment;
1080 while (proc_maps.Next(&segment)) {
1081 if ((segment.end >= 3 * gbyte) && segment.IsWritable()) return 0;
1082 }
1083
1084#if !SANITIZER_ANDROID
1085 // Even if nothing is mapped, top Gb may still be accessible
1086 // if we are running on 64-bit kernel.
1087 // Uname may report misleading results if personality type
1088 // is modified (e.g. under schroot) so check this as well.
1089 struct utsname uname_info;
1090 int pers = personality(0xffffffffUL);
1091 if (!(pers & PER_MASK) && internal_uname(&uname_info) == 0 &&
1092 internal_strstr(uname_info.machine, "64"))
1093 return 0;
1094#endif // SANITIZER_ANDROID
1095
1096 // Top gigabyte is reserved for kernel.
1097 return gbyte;
1098#else
1099 return 0;
1100#endif // SANITIZER_LINUX && !SANITIZER_X32
1101}
1102#endif // SANITIZER_WORDSIZE == 32
1103
1104uptr GetMaxVirtualAddress() {
1105#if SANITIZER_NETBSD && defined(__x86_64__)
1106 return 0x7f7ffffff000ULL; // (0x00007f8000000000 - PAGE_SIZE)
1107#elif SANITIZER_WORDSIZE == 64
1108# if defined(__powerpc64__) || defined(__aarch64__)
1109 // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
1110 // We somehow need to figure out which one we are using now and choose
1111 // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
1112 // Note that with 'ulimit -s unlimited' the stack is moved away from the top
1113 // of the address space, so simply checking the stack address is not enough.
1114 // This should (does) work for both PowerPC64 Endian modes.
1115 // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
1116 return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
1117#elif SANITIZER_RISCV64
1118 return (1ULL << 38) - 1;
1119# elif SANITIZER_MIPS64
1120 return (1ULL << 40) - 1; // 0x000000ffffffffffUL;
1121# elif defined(__s390x__)
1122 return (1ULL << 53) - 1; // 0x001fffffffffffffUL;
1123#elif defined(__sparc__)
1124 return ~(uptr)0;
1125# else
1126 return (1ULL << 47) - 1; // 0x00007fffffffffffUL;
1127# endif
1128#else // SANITIZER_WORDSIZE == 32
1129# if defined(__s390__)
1130 return (1ULL << 31) - 1; // 0x7fffffff;
1131# else
1132 return (1ULL << 32) - 1; // 0xffffffff;
1133# endif
1134#endif // SANITIZER_WORDSIZE
1135}
1136
1137uptr GetMaxUserVirtualAddress() {
1138 uptr addr = GetMaxVirtualAddress();
1139#if SANITIZER_WORDSIZE == 32 && !defined(__s390__)
1140 if (!common_flags()->full_address_space)
1141 addr -= GetKernelAreaSize();
1142 CHECK_LT(reinterpret_cast<uptr>(&addr), addr);
1143#endif
1144 return addr;
1145}
1146
1147#if !SANITIZER_ANDROID
1148uptr GetPageSize() {
1149#if SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__)) && \
1150 defined(EXEC_PAGESIZE)
1151 return EXEC_PAGESIZE;
1152#elif SANITIZER_FREEBSD || SANITIZER_NETBSD
1153// Use sysctl as sysconf can trigger interceptors internally.
1154 int pz = 0;
1155 uptr pzl = sizeof(pz);
1156 int mib[2] = {CTL_HW, HW_PAGESIZE};
1157 int rv = internal_sysctl(mib, 2, &pz, &pzl, nullptr, 0);
1158 CHECK_EQ(rv, 0);
1159 return (uptr)pz;
1160#elif SANITIZER_USE_GETAUXVAL
1161 return getauxval(AT_PAGESZ);
1162#else
1163 return sysconf(_SC_PAGESIZE); // EXEC_PAGESIZE may not be trustworthy.
1164#endif
1165}
1166#endif // !SANITIZER_ANDROID
1167
1168uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
1169#if SANITIZER_SOLARIS
1170 const char *default_module_name = getexecname();
1171 CHECK_NE(default_module_name, NULL);
1172 return internal_snprintf(buf, buf_len, "%s", default_module_name);
1173#else
1174#if SANITIZER_FREEBSD || SANITIZER_NETBSD
1175#if SANITIZER_FREEBSD
1176 const int Mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
1177#else
1178 const int Mib[4] = {CTL_KERN, KERN_PROC_ARGS, -1, KERN_PROC_PATHNAME};
1179#endif
1180 const char *default_module_name = "kern.proc.pathname";
1181 uptr Size = buf_len;
1182 bool IsErr =
1183 (internal_sysctl(Mib, ARRAY_SIZE(Mib), buf, &Size, NULL, 0) != 0);
1184 int readlink_error = IsErr ? errno : 0;
1185 uptr module_name_len = Size;
1186#else
1187 const char *default_module_name = "/proc/self/exe";
1188 uptr module_name_len = internal_readlink(
1189 default_module_name, buf, buf_len);
1190 int readlink_error;
1191 bool IsErr = internal_iserror(module_name_len, &readlink_error);
1192#endif // SANITIZER_SOLARIS
1193 if (IsErr) {
1194 // We can't read binary name for some reason, assume it's unknown.
1195 Report("WARNING: reading executable name failed with errno %d, "
1196 "some stack frames may not be symbolized\n", readlink_error);
1197 module_name_len = internal_snprintf(buf, buf_len, "%s",
1198 default_module_name);
1199 CHECK_LT(module_name_len, buf_len);
1200 }
1201 return module_name_len;
1202#endif
1203}
1204
1205uptr ReadLongProcessName(/*out*/ char *buf, uptr buf_len) {
1206#if SANITIZER_LINUX
1207 char *tmpbuf;
1208 uptr tmpsize;
1209 uptr tmplen;
1210 if (ReadFileToBuffer("/proc/self/cmdline", &tmpbuf, &tmpsize, &tmplen,
1211 1024 * 1024)) {
1212 internal_strncpy(buf, tmpbuf, buf_len);
1213 UnmapOrDie(tmpbuf, tmpsize);
1214 return internal_strlen(buf);
1215 }
1216#endif
1217 return ReadBinaryName(buf, buf_len);
1218}
1219
1220// Match full names of the form /path/to/base_name{-,.}*
1221bool LibraryNameIs(const char *full_name, const char *base_name) {
1222 const char *name = full_name;
1223 // Strip path.
1224 while (*name != '\0') name++;
1225 while (name > full_name && *name != '/') name--;
1226 if (*name == '/') name++;
1227 uptr base_name_length = internal_strlen(base_name);
1228 if (internal_strncmp(name, base_name, base_name_length)) return false;
1229 return (name[base_name_length] == '-' || name[base_name_length] == '.');
1230}
1231
1232#if !SANITIZER_ANDROID
1233// Call cb for each region mapped by map.
1234void ForEachMappedRegion(link_map *map, void (*cb)(const void *, uptr)) {
1235 CHECK_NE(map, nullptr);
1236#if !SANITIZER_FREEBSD
1237 typedef ElfW(Phdr) Elf_Phdr;
1238 typedef ElfW(Ehdr) Elf_Ehdr;
1239#endif // !SANITIZER_FREEBSD
1240 char *base = (char *)map->l_addr;
1241 Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
1242 char *phdrs = base + ehdr->e_phoff;
1243 char *phdrs_end = phdrs + ehdr->e_phnum * ehdr->e_phentsize;
1244
1245 // Find the segment with the minimum base so we can "relocate" the p_vaddr
1246 // fields. Typically ET_DYN objects (DSOs) have base of zero and ET_EXEC
1247 // objects have a non-zero base.
1248 uptr preferred_base = (uptr)-1;
1249 for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1250 Elf_Phdr *phdr = (Elf_Phdr *)iter;
1251 if (phdr->p_type == PT_LOAD && preferred_base > (uptr)phdr->p_vaddr)
1252 preferred_base = (uptr)phdr->p_vaddr;
1253 }
1254
1255 // Compute the delta from the real base to get a relocation delta.
1256 sptr delta = (uptr)base - preferred_base;
1257 // Now we can figure out what the loader really mapped.
1258 for (char *iter = phdrs; iter != phdrs_end; iter += ehdr->e_phentsize) {
1259 Elf_Phdr *phdr = (Elf_Phdr *)iter;
1260 if (phdr->p_type == PT_LOAD) {
1261 uptr seg_start = phdr->p_vaddr + delta;
1262 uptr seg_end = seg_start + phdr->p_memsz;
1263 // None of these values are aligned. We consider the ragged edges of the
1264 // load command as defined, since they are mapped from the file.
1265 seg_start = RoundDownTo(seg_start, GetPageSizeCached());
1266 seg_end = RoundUpTo(seg_end, GetPageSizeCached());
1267 cb((void *)seg_start, seg_end - seg_start);
1268 }
1269 }
1270}
1271#endif
1272
1273#if SANITIZER_LINUX
1274#if defined(__x86_64__)
1275// We cannot use glibc's clone wrapper, because it messes with the child
1276// task's TLS. It writes the PID and TID of the child task to its thread
1277// descriptor, but in our case the child task shares the thread descriptor with
1278// the parent (because we don't know how to allocate a new thread
1279// descriptor to keep glibc happy). So the stock version of clone(), when
1280// used with CLONE_VM, would end up corrupting the parent's thread descriptor.
1281uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1282 int *parent_tidptr, void *newtls, int *child_tidptr) {
1283 long long res;
1284 if (!fn || !child_stack)
1285 return -EINVAL;
1286 CHECK_EQ(0, (uptr)child_stack % 16);
1287 child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1288 ((unsigned long long *)child_stack)[0] = (uptr)fn;
1289 ((unsigned long long *)child_stack)[1] = (uptr)arg;
1290 register void *r8 __asm__("r8") = newtls;
1291 register int *r10 __asm__("r10") = child_tidptr;
1292 __asm__ __volatile__(
1293 /* %rax = syscall(%rax = SYSCALL(clone),
1294 * %rdi = flags,
1295 * %rsi = child_stack,
1296 * %rdx = parent_tidptr,
1297 * %r8 = new_tls,
1298 * %r10 = child_tidptr)
1299 */
1300 "syscall\n"
1301
1302 /* if (%rax != 0)
1303 * return;
1304 */
1305 "testq %%rax,%%rax\n"
1306 "jnz 1f\n"
1307
1308 /* In the child. Terminate unwind chain. */
1309 // XXX: We should also terminate the CFI unwind chain
1310 // here. Unfortunately clang 3.2 doesn't support the
1311 // necessary CFI directives, so we skip that part.
1312 "xorq %%rbp,%%rbp\n"
1313
1314 /* Call "fn(arg)". */
1315 "popq %%rax\n"
1316 "popq %%rdi\n"
1317 "call *%%rax\n"
1318
1319 /* Call _exit(%rax). */
1320 "movq %%rax,%%rdi\n"
1321 "movq %2,%%rax\n"
1322 "syscall\n"
1323
1324 /* Return to parent. */
1325 "1:\n"
1326 : "=a" (res)
1327 : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1328 "S"(child_stack),
1329 "D"(flags),
1330 "d"(parent_tidptr),
1331 "r"(r8),
1332 "r"(r10)
1333 : "memory", "r11", "rcx");
1334 return res;
1335}
1336#elif defined(__mips__)
1337uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1338 int *parent_tidptr, void *newtls, int *child_tidptr) {
1339 long long res;
1340 if (!fn || !child_stack)
1341 return -EINVAL;
1342 CHECK_EQ(0, (uptr)child_stack % 16);
1343 child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1344 ((unsigned long long *)child_stack)[0] = (uptr)fn;
1345 ((unsigned long long *)child_stack)[1] = (uptr)arg;
1346 register void *a3 __asm__("$7") = newtls;
1347 register int *a4 __asm__("$8") = child_tidptr;
1348 // We don't have proper CFI directives here because it requires alot of code
1349 // for very marginal benefits.
1350 __asm__ __volatile__(
1351 /* $v0 = syscall($v0 = __NR_clone,
1352 * $a0 = flags,
1353 * $a1 = child_stack,
1354 * $a2 = parent_tidptr,
1355 * $a3 = new_tls,
1356 * $a4 = child_tidptr)
1357 */
1358 ".cprestore 16;\n"
1359 "move $4,%1;\n"
1360 "move $5,%2;\n"
1361 "move $6,%3;\n"
1362 "move $7,%4;\n"
1363 /* Store the fifth argument on stack
1364 * if we are using 32-bit abi.
1365 */
1366#if SANITIZER_WORDSIZE == 32
1367 "lw %5,16($29);\n"
1368#else
1369 "move $8,%5;\n"
1370#endif
1371 "li $2,%6;\n"
1372 "syscall;\n"
1373
1374 /* if ($v0 != 0)
1375 * return;
1376 */
1377 "bnez $2,1f;\n"
1378
1379 /* Call "fn(arg)". */
1380#if SANITIZER_WORDSIZE == 32
1381#ifdef __BIG_ENDIAN__
1382 "lw $25,4($29);\n"
1383 "lw $4,12($29);\n"
1384#else
1385 "lw $25,0($29);\n"
1386 "lw $4,8($29);\n"
1387#endif
1388#else
1389 "ld $25,0($29);\n"
1390 "ld $4,8($29);\n"
1391#endif
1392 "jal $25;\n"
1393
1394 /* Call _exit($v0). */
1395 "move $4,$2;\n"
1396 "li $2,%7;\n"
1397 "syscall;\n"
1398
1399 /* Return to parent. */
1400 "1:\n"
1401 : "=r" (res)
1402 : "r"(flags),
1403 "r"(child_stack),
1404 "r"(parent_tidptr),
1405 "r"(a3),
1406 "r"(a4),
1407 "i"(__NR_clone),
1408 "i"(__NR_exit)
1409 : "memory", "$29" );
1410 return res;
1411}
1412#elif SANITIZER_RISCV64
1413uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1414 int *parent_tidptr, void *newtls, int *child_tidptr) {
1415 if (!fn || !child_stack)
1416 return -EINVAL;
1417
1418 CHECK_EQ(0, (uptr)child_stack % 16);
1419
1420 register int res __asm__("a0");
1421 register int __flags __asm__("a0") = flags;
1422 register void *__stack __asm__("a1") = child_stack;
1423 register int *__ptid __asm__("a2") = parent_tidptr;
1424 register void *__tls __asm__("a3") = newtls;
1425 register int *__ctid __asm__("a4") = child_tidptr;
1426 register int (*__fn)(void *) __asm__("a5") = fn;
1427 register void *__arg __asm__("a6") = arg;
1428 register int nr_clone __asm__("a7") = __NR_clone;
1429
1430 __asm__ __volatile__(
1431 "ecall\n"
1432
1433 /* if (a0 != 0)
1434 * return a0;
1435 */
1436 "bnez a0, 1f\n"
1437
1438 // In the child, now. Call "fn(arg)".
1439 "mv a0, a6\n"
1440 "jalr a5\n"
1441
1442 // Call _exit(a0).
1443 "addi a7, zero, %9\n"
1444 "ecall\n"
1445 "1:\n"
1446
1447 : "=r"(res)
1448 : "0"(__flags), "r"(__stack), "r"(__ptid), "r"(__tls), "r"(__ctid),
1449 "r"(__fn), "r"(__arg), "r"(nr_clone), "i"(__NR_exit)
1450 : "memory");
1451 return res;
1452}
1453#elif defined(__aarch64__)
1454uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1455 int *parent_tidptr, void *newtls, int *child_tidptr) {
1456 register long long res __asm__("x0");
1457 if (!fn || !child_stack)
1458 return -EINVAL;
1459 CHECK_EQ(0, (uptr)child_stack % 16);
1460 child_stack = (char *)child_stack - 2 * sizeof(unsigned long long);
1461 ((unsigned long long *)child_stack)[0] = (uptr)fn;
1462 ((unsigned long long *)child_stack)[1] = (uptr)arg;
1463
1464 register int (*__fn)(void *) __asm__("x0") = fn;
1465 register void *__stack __asm__("x1") = child_stack;
1466 register int __flags __asm__("x2") = flags;
1467 register void *__arg __asm__("x3") = arg;
1468 register int *__ptid __asm__("x4") = parent_tidptr;
1469 register void *__tls __asm__("x5") = newtls;
1470 register int *__ctid __asm__("x6") = child_tidptr;
1471
1472 __asm__ __volatile__(
1473 "mov x0,x2\n" /* flags */
1474 "mov x2,x4\n" /* ptid */
1475 "mov x3,x5\n" /* tls */
1476 "mov x4,x6\n" /* ctid */
1477 "mov x8,%9\n" /* clone */
1478
1479 "svc 0x0\n"
1480
1481 /* if (%r0 != 0)
1482 * return %r0;
1483 */
1484 "cmp x0, #0\n"
1485 "bne 1f\n"
1486
1487 /* In the child, now. Call "fn(arg)". */
1488 "ldp x1, x0, [sp], #16\n"
1489 "blr x1\n"
1490
1491 /* Call _exit(%r0). */
1492 "mov x8, %10\n"
1493 "svc 0x0\n"
1494 "1:\n"
1495
1496 : "=r" (res)
1497 : "i"(-EINVAL),
1498 "r"(__fn), "r"(__stack), "r"(__flags), "r"(__arg),
1499 "r"(__ptid), "r"(__tls), "r"(__ctid),
1500 "i"(__NR_clone), "i"(__NR_exit)
1501 : "x30", "memory");
1502 return res;
1503}
1504#elif defined(__powerpc64__)
1505uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1506 int *parent_tidptr, void *newtls, int *child_tidptr) {
1507 long long res;
1508// Stack frame structure.
1509#if SANITIZER_PPC64V1
1510// Back chain == 0 (SP + 112)
1511// Frame (112 bytes):
1512// Parameter save area (SP + 48), 8 doublewords
1513// TOC save area (SP + 40)
1514// Link editor doubleword (SP + 32)
1515// Compiler doubleword (SP + 24)
1516// LR save area (SP + 16)
1517// CR save area (SP + 8)
1518// Back chain (SP + 0)
1519# define FRAME_SIZE 112
1520# define FRAME_TOC_SAVE_OFFSET 40
1521#elif SANITIZER_PPC64V2
1522// Back chain == 0 (SP + 32)
1523// Frame (32 bytes):
1524// TOC save area (SP + 24)
1525// LR save area (SP + 16)
1526// CR save area (SP + 8)
1527// Back chain (SP + 0)
1528# define FRAME_SIZE 32
1529# define FRAME_TOC_SAVE_OFFSET 24
1530#else
1531# error "Unsupported PPC64 ABI"
1532#endif
1533 if (!fn || !child_stack)
1534 return -EINVAL;
1535 CHECK_EQ(0, (uptr)child_stack % 16);
1536
1537 register int (*__fn)(void *) __asm__("r3") = fn;
1538 register void *__cstack __asm__("r4") = child_stack;
1539 register int __flags __asm__("r5") = flags;
1540 register void *__arg __asm__("r6") = arg;
1541 register int *__ptidptr __asm__("r7") = parent_tidptr;
1542 register void *__newtls __asm__("r8") = newtls;
1543 register int *__ctidptr __asm__("r9") = child_tidptr;
1544
1545 __asm__ __volatile__(
1546 /* fn and arg are saved across the syscall */
1547 "mr 28, %5\n\t"
1548 "mr 27, %8\n\t"
1549
1550 /* syscall
1551 r0 == __NR_clone
1552 r3 == flags
1553 r4 == child_stack
1554 r5 == parent_tidptr
1555 r6 == newtls
1556 r7 == child_tidptr */
1557 "mr 3, %7\n\t"
1558 "mr 5, %9\n\t"
1559 "mr 6, %10\n\t"
1560 "mr 7, %11\n\t"
1561 "li 0, %3\n\t"
1562 "sc\n\t"
1563
1564 /* Test if syscall was successful */
1565 "cmpdi cr1, 3, 0\n\t"
1566 "crandc cr1*4+eq, cr1*4+eq, cr0*4+so\n\t"
1567 "bne- cr1, 1f\n\t"
1568
1569 /* Set up stack frame */
1570 "li 29, 0\n\t"
1571 "stdu 29, -8(1)\n\t"
1572 "stdu 1, -%12(1)\n\t"
1573 /* Do the function call */
1574 "std 2, %13(1)\n\t"
1575#if SANITIZER_PPC64V1
1576 "ld 0, 0(28)\n\t"
1577 "ld 2, 8(28)\n\t"
1578 "mtctr 0\n\t"
1579#elif SANITIZER_PPC64V2
1580 "mr 12, 28\n\t"
1581 "mtctr 12\n\t"
1582#else
1583# error "Unsupported PPC64 ABI"
1584#endif
1585 "mr 3, 27\n\t"
1586 "bctrl\n\t"
1587 "ld 2, %13(1)\n\t"
1588
1589 /* Call _exit(r3) */
1590 "li 0, %4\n\t"
1591 "sc\n\t"
1592
1593 /* Return to parent */
1594 "1:\n\t"
1595 "mr %0, 3\n\t"
1596 : "=r" (res)
1597 : "0" (-1),
1598 "i" (EINVAL),
1599 "i" (__NR_clone),
1600 "i" (__NR_exit),
1601 "r" (__fn),
1602 "r" (__cstack),
1603 "r" (__flags),
1604 "r" (__arg),
1605 "r" (__ptidptr),
1606 "r" (__newtls),
1607 "r" (__ctidptr),
1608 "i" (FRAME_SIZE),
1609 "i" (FRAME_TOC_SAVE_OFFSET)
1610 : "cr0", "cr1", "memory", "ctr", "r0", "r27", "r28", "r29");
1611 return res;
1612}
1613#elif defined(__i386__)
1614uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1615 int *parent_tidptr, void *newtls, int *child_tidptr) {
1616 int res;
1617 if (!fn || !child_stack)
1618 return -EINVAL;
1619 CHECK_EQ(0, (uptr)child_stack % 16);
1620 child_stack = (char *)child_stack - 7 * sizeof(unsigned int);
1621 ((unsigned int *)child_stack)[0] = (uptr)flags;
1622 ((unsigned int *)child_stack)[1] = (uptr)0;
1623 ((unsigned int *)child_stack)[2] = (uptr)fn;
1624 ((unsigned int *)child_stack)[3] = (uptr)arg;
1625 __asm__ __volatile__(
1626 /* %eax = syscall(%eax = SYSCALL(clone),
1627 * %ebx = flags,
1628 * %ecx = child_stack,
1629 * %edx = parent_tidptr,
1630 * %esi = new_tls,
1631 * %edi = child_tidptr)
1632 */
1633
1634 /* Obtain flags */
1635 "movl (%%ecx), %%ebx\n"
1636 /* Do the system call */
1637 "pushl %%ebx\n"
1638 "pushl %%esi\n"
1639 "pushl %%edi\n"
1640 /* Remember the flag value. */
1641 "movl %%ebx, (%%ecx)\n"
1642 "int $0x80\n"
1643 "popl %%edi\n"
1644 "popl %%esi\n"
1645 "popl %%ebx\n"
1646
1647 /* if (%eax != 0)
1648 * return;
1649 */
1650
1651 "test %%eax,%%eax\n"
1652 "jnz 1f\n"
1653
1654 /* terminate the stack frame */
1655 "xorl %%ebp,%%ebp\n"
1656 /* Call FN. */
1657 "call *%%ebx\n"
1658#ifdef PIC
1659 "call here\n"
1660 "here:\n"
1661 "popl %%ebx\n"
1662 "addl $_GLOBAL_OFFSET_TABLE_+[.-here], %%ebx\n"
1663#endif
1664 /* Call exit */
1665 "movl %%eax, %%ebx\n"
1666 "movl %2, %%eax\n"
1667 "int $0x80\n"
1668 "1:\n"
1669 : "=a" (res)
1670 : "a"(SYSCALL(clone)), "i"(SYSCALL(exit)),
1671 "c"(child_stack),
1672 "d"(parent_tidptr),
1673 "S"(newtls),
1674 "D"(child_tidptr)
1675 : "memory");
1676 return res;
1677}
1678#elif defined(__arm__)
1679uptr internal_clone(int (*fn)(void *), void *child_stack, int flags, void *arg,
1680 int *parent_tidptr, void *newtls, int *child_tidptr) {
1681 unsigned int res;
1682 if (!fn || !child_stack)
1683 return -EINVAL;
1684 child_stack = (char *)child_stack - 2 * sizeof(unsigned int);
1685 ((unsigned int *)child_stack)[0] = (uptr)fn;
1686 ((unsigned int *)child_stack)[1] = (uptr)arg;
1687 register int r0 __asm__("r0") = flags;
1688 register void *r1 __asm__("r1") = child_stack;
1689 register int *r2 __asm__("r2") = parent_tidptr;
1690 register void *r3 __asm__("r3") = newtls;
1691 register int *r4 __asm__("r4") = child_tidptr;
1692 register int r7 __asm__("r7") = __NR_clone;
1693
1694#if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
1695# define ARCH_HAS_BX
1696#endif
1697#if __ARM_ARCH > 4
1698# define ARCH_HAS_BLX
1699#endif
1700
1701#ifdef ARCH_HAS_BX
1702# ifdef ARCH_HAS_BLX
1703# define BLX(R) "blx " #R "\n"
1704# else
1705# define BLX(R) "mov lr, pc; bx " #R "\n"
1706# endif
1707#else
1708# define BLX(R) "mov lr, pc; mov pc," #R "\n"
1709#endif
1710
1711 __asm__ __volatile__(
1712 /* %r0 = syscall(%r7 = SYSCALL(clone),
1713 * %r0 = flags,
1714 * %r1 = child_stack,
1715 * %r2 = parent_tidptr,
1716 * %r3 = new_tls,
1717 * %r4 = child_tidptr)
1718 */
1719
1720 /* Do the system call */
1721 "swi 0x0\n"
1722
1723 /* if (%r0 != 0)
1724 * return %r0;
1725 */
1726 "cmp r0, #0\n"
1727 "bne 1f\n"
1728
1729 /* In the child, now. Call "fn(arg)". */
1730 "ldr r0, [sp, #4]\n"
1731 "ldr ip, [sp], #8\n"
1732 BLX(ip)
1733 /* Call _exit(%r0). */
1734 "mov r7, %7\n"
1735 "swi 0x0\n"
1736 "1:\n"
1737 "mov %0, r0\n"
1738 : "=r"(res)
1739 : "r"(r0), "r"(r1), "r"(r2), "r"(r3), "r"(r4), "r"(r7),
1740 "i"(__NR_exit)
1741 : "memory");
1742 return res;
1743}
1744#endif
1745#endif // SANITIZER_LINUX
1746
1747#if SANITIZER_LINUX
1748int internal_uname(struct utsname *buf) {
1749 return internal_syscall(SYSCALL(uname), buf);
1750}
1751#endif
1752
1753#if SANITIZER_ANDROID
1754#if __ANDROID_API__ < 21
1755extern "C" __attribute__((weak)) int dl_iterate_phdr(
1756 int (*)(struct dl_phdr_info *, size_t, void *), void *);
1757#endif
1758
1759static int dl_iterate_phdr_test_cb(struct dl_phdr_info *info, size_t size,
1760 void *data) {
1761 // Any name starting with "lib" indicates a bug in L where library base names
1762 // are returned instead of paths.
1763 if (info->dlpi_name && info->dlpi_name[0] == 'l' &&
1764 info->dlpi_name[1] == 'i' && info->dlpi_name[2] == 'b') {
1765 *(bool *)data = true;
1766 return 1;
1767 }
1768 return 0;
1769}
1770
1771static atomic_uint32_t android_api_level;
1772
1773static AndroidApiLevel AndroidDetectApiLevelStatic() {
1774#if __ANDROID_API__ <= 19
1775 return ANDROID_KITKAT;
1776#elif __ANDROID_API__ <= 22
1777 return ANDROID_LOLLIPOP_MR1;
1778#else
1779 return ANDROID_POST_LOLLIPOP;
1780#endif
1781}
1782
1783static AndroidApiLevel AndroidDetectApiLevel() {
1784 if (!&dl_iterate_phdr)
1785 return ANDROID_KITKAT; // K or lower
1786 bool base_name_seen = false;
1787 dl_iterate_phdr(dl_iterate_phdr_test_cb, &base_name_seen);
1788 if (base_name_seen)
1789 return ANDROID_LOLLIPOP_MR1; // L MR1
1790 return ANDROID_POST_LOLLIPOP; // post-L
1791 // Plain L (API level 21) is completely broken wrt ASan and not very
1792 // interesting to detect.
1793}
1794
1795extern "C" __attribute__((weak)) void* _DYNAMIC;
1796
1797AndroidApiLevel AndroidGetApiLevel() {
1798 AndroidApiLevel level =
1799 (AndroidApiLevel)atomic_load(&android_api_level, memory_order_relaxed);
1800 if (level) return level;
1801 level = &_DYNAMIC == nullptr ? AndroidDetectApiLevelStatic()
1802 : AndroidDetectApiLevel();
1803 atomic_store(&android_api_level, level, memory_order_relaxed);
1804 return level;
1805}
1806
1807#endif
1808
1809static HandleSignalMode GetHandleSignalModeImpl(int signum) {
1810 switch (signum) {
1811 case SIGABRT:
1812 return common_flags()->handle_abort;
1813 case SIGILL:
1814 return common_flags()->handle_sigill;
1815 case SIGTRAP:
1816 return common_flags()->handle_sigtrap;
1817 case SIGFPE:
1818 return common_flags()->handle_sigfpe;
1819 case SIGSEGV:
1820 return common_flags()->handle_segv;
1821 case SIGBUS:
1822 return common_flags()->handle_sigbus;
1823 }
1824 return kHandleSignalNo;
1825}
1826
1827HandleSignalMode GetHandleSignalMode(int signum) {
1828 HandleSignalMode result = GetHandleSignalModeImpl(signum);
1829 if (result == kHandleSignalYes && !common_flags()->allow_user_segv_handler)
1830 return kHandleSignalExclusive;
1831 return result;
1832}
1833
1834#if !SANITIZER_GO
1835void *internal_start_thread(void *(*func)(void *arg), void *arg) {
1836 if (&real_pthread_create == 0)
1837 return nullptr;
1838 // Start the thread with signals blocked, otherwise it can steal user signals.
1839 ScopedBlockSignals block(nullptr);
1840 void *th;
1841 real_pthread_create(&th, nullptr, func, arg);
1842 return th;
1843}
1844
1845void internal_join_thread(void *th) {
1846 if (&real_pthread_join)
1847 real_pthread_join(th, nullptr);
1848}
1849#else
1850void *internal_start_thread(void *(*func)(void *), void *arg) { return 0; }
1851
1852void internal_join_thread(void *th) {}
1853#endif
1854
1855#if SANITIZER_LINUX && defined(__aarch64__)
1856// Android headers in the older NDK releases miss this definition.
1857struct __sanitizer_esr_context {
1858 struct _aarch64_ctx head;
1859 uint64_t esr;
1860};
1861
1862static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
1863 static const u32 kEsrMagic = 0x45535201;
1864 u8 *aux = reinterpret_cast<u8 *>(ucontext->uc_mcontext.__reserved);
1865 while (true) {
1866 _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
1867 if (ctx->size == 0) break;
1868 if (ctx->magic == kEsrMagic) {
1869 *esr = ((__sanitizer_esr_context *)ctx)->esr;
1870 return true;
1871 }
1872 aux += ctx->size;
1873 }
1874 return false;
1875}
1876#elif SANITIZER_FREEBSD && defined(__aarch64__)
1877// FreeBSD doesn't provide ESR in the ucontext.
1878static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
1879 return false;
1880}
1881#endif
1882
1883using Context = ucontext_t;
1884
1885SignalContext::WriteFlag SignalContext::GetWriteFlag() const {
1886 Context *ucontext = (Context *)context;
1887#if defined(__x86_64__) || defined(__i386__)
1888 static const uptr PF_WRITE = 1U << 1;
1889#if SANITIZER_FREEBSD
1890 uptr err = ucontext->uc_mcontext.mc_err;
1891#elif SANITIZER_NETBSD
1892 uptr err = ucontext->uc_mcontext.__gregs[_REG_ERR];
1893#elif SANITIZER_SOLARIS && defined(__i386__)
1894 const int Err = 13;
1895 uptr err = ucontext->uc_mcontext.gregs[Err];
1896#else
1897 uptr err = ucontext->uc_mcontext.gregs[REG_ERR];
1898#endif // SANITIZER_FREEBSD
1899 return err & PF_WRITE ? Write : Read;
1900#elif defined(__mips__)
1901 uint32_t *exception_source;
1902 uint32_t faulty_instruction;
1903 uint32_t op_code;
1904
1905 exception_source = (uint32_t *)ucontext->uc_mcontext.pc;
1906 faulty_instruction = (uint32_t)(*exception_source);
1907
1908 op_code = (faulty_instruction >> 26) & 0x3f;
1909
1910 // FIXME: Add support for FPU, microMIPS, DSP, MSA memory instructions.
1911 switch (op_code) {
1912 case 0x28: // sb
1913 case 0x29: // sh
1914 case 0x2b: // sw
1915 case 0x3f: // sd
1916#if __mips_isa_rev < 6
1917 case 0x2c: // sdl
1918 case 0x2d: // sdr
1919 case 0x2a: // swl
1920 case 0x2e: // swr
1921#endif
1922 return SignalContext::Write;
1923
1924 case 0x20: // lb
1925 case 0x24: // lbu
1926 case 0x21: // lh
1927 case 0x25: // lhu
1928 case 0x23: // lw
1929 case 0x27: // lwu
1930 case 0x37: // ld
1931#if __mips_isa_rev < 6
1932 case 0x1a: // ldl
1933 case 0x1b: // ldr
1934 case 0x22: // lwl
1935 case 0x26: // lwr
1936#endif
1937 return SignalContext::Read;
1938#if __mips_isa_rev == 6
1939 case 0x3b: // pcrel
1940 op_code = (faulty_instruction >> 19) & 0x3;
1941 switch (op_code) {
1942 case 0x1: // lwpc
1943 case 0x2: // lwupc
1944 return SignalContext::Read;
1945 }
1946#endif
1947 }
1948 return SignalContext::Unknown;
1949#elif defined(__arm__)
1950 static const uptr FSR_WRITE = 1U << 11;
1951 uptr fsr = ucontext->uc_mcontext.error_code;
1952 return fsr & FSR_WRITE ? Write : Read;
1953#elif defined(__aarch64__)
1954 static const u64 ESR_ELx_WNR = 1U << 6;
1955 u64 esr;
1956 if (!Aarch64GetESR(ucontext, &esr)) return Unknown;
1957 return esr & ESR_ELx_WNR ? Write : Read;
1958#elif defined(__sparc__)
1959 // Decode the instruction to determine the access type.
1960 // From OpenSolaris $SRC/uts/sun4/os/trap.c (get_accesstype).
1961#if SANITIZER_SOLARIS
1962 uptr pc = ucontext->uc_mcontext.gregs[REG_PC];
1963#else
1964 // Historical BSDism here.
1965 struct sigcontext *scontext = (struct sigcontext *)context;
1966#if defined(__arch64__)
1967 uptr pc = scontext->sigc_regs.tpc;
1968#else
1969 uptr pc = scontext->si_regs.pc;
1970#endif
1971#endif
1972 u32 instr = *(u32 *)pc;
1973 return (instr >> 21) & 1 ? Write: Read;
1974#elif defined(__riscv)
1975#if SANITIZER_FREEBSD
1976 unsigned long pc = ucontext->uc_mcontext.mc_gpregs.gp_sepc;
1977#else
1978 unsigned long pc = ucontext->uc_mcontext.__gregs[REG_PC];
1979#endif
1980 unsigned faulty_instruction = *(uint16_t *)pc;
1981
1982#if defined(__riscv_compressed)
1983 if ((faulty_instruction & 0x3) != 0x3) { // it's a compressed instruction
1984 // set op_bits to the instruction bits [1, 0, 15, 14, 13]
1985 unsigned op_bits =
1986 ((faulty_instruction & 0x3) << 3) | (faulty_instruction >> 13);
1987 unsigned rd = faulty_instruction & 0xF80; // bits 7-11, inclusive
1988 switch (op_bits) {
1989 case 0b10'010: // c.lwsp (rd != x0)
1990#if __riscv_xlen == 64
1991 case 0b10'011: // c.ldsp (rd != x0)
1992#endif
1993 return rd ? SignalContext::Read : SignalContext::Unknown;
1994 case 0b00'010: // c.lw
1995#if __riscv_flen >= 32 && __riscv_xlen == 32
1996 case 0b10'011: // c.flwsp
1997#endif
1998#if __riscv_flen >= 32 || __riscv_xlen == 64
1999 case 0b00'011: // c.flw / c.ld
2000#endif
2001#if __riscv_flen == 64
2002 case 0b00'001: // c.fld
2003 case 0b10'001: // c.fldsp
2004#endif
2005 return SignalContext::Read;
2006 case 0b00'110: // c.sw
2007 case 0b10'110: // c.swsp
2008#if __riscv_flen >= 32 || __riscv_xlen == 64
2009 case 0b00'111: // c.fsw / c.sd
2010 case 0b10'111: // c.fswsp / c.sdsp
2011#endif
2012#if __riscv_flen == 64
2013 case 0b00'101: // c.fsd
2014 case 0b10'101: // c.fsdsp
2015#endif
2016 return SignalContext::Write;
2017 default:
2018 return SignalContext::Unknown;
2019 }
2020 }
2021#endif
2022
2023 unsigned opcode = faulty_instruction & 0x7f; // lower 7 bits
2024 unsigned funct3 = (faulty_instruction >> 12) & 0x7; // bits 12-14, inclusive
2025 switch (opcode) {
2026 case 0b0000011: // loads
2027 switch (funct3) {
2028 case 0b000: // lb
2029 case 0b001: // lh
2030 case 0b010: // lw
2031#if __riscv_xlen == 64
2032 case 0b011: // ld
2033#endif
2034 case 0b100: // lbu
2035 case 0b101: // lhu
2036 return SignalContext::Read;
2037 default:
2038 return SignalContext::Unknown;
2039 }
2040 case 0b0100011: // stores
2041 switch (funct3) {
2042 case 0b000: // sb
2043 case 0b001: // sh
2044 case 0b010: // sw
2045#if __riscv_xlen == 64
2046 case 0b011: // sd
2047#endif
2048 return SignalContext::Write;
2049 default:
2050 return SignalContext::Unknown;
2051 }
2052#if __riscv_flen >= 32
2053 case 0b0000111: // floating-point loads
2054 switch (funct3) {
2055 case 0b010: // flw
2056#if __riscv_flen == 64
2057 case 0b011: // fld
2058#endif
2059 return SignalContext::Read;
2060 default:
2061 return SignalContext::Unknown;
2062 }
2063 case 0b0100111: // floating-point stores
2064 switch (funct3) {
2065 case 0b010: // fsw
2066#if __riscv_flen == 64
2067 case 0b011: // fsd
2068#endif
2069 return SignalContext::Write;
2070 default:
2071 return SignalContext::Unknown;
2072 }
2073#endif
2074 default:
2075 return SignalContext::Unknown;
2076 }
2077#else
2078 (void)ucontext;
2079 return Unknown; // FIXME: Implement.
2080#endif
2081}
2082
2083bool SignalContext::IsTrueFaultingAddress() const {
2084 auto si = static_cast<const siginfo_t *>(siginfo);
2085 // SIGSEGV signals without a true fault address have si_code set to 128.
2086 return si->si_signo == SIGSEGV && si->si_code != 128;
2087}
2088
2089void SignalContext::DumpAllRegisters(void *context) {
2090 // FIXME: Implement this.
2091}
2092
2093static void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
2094#if SANITIZER_NETBSD
2095 // This covers all NetBSD architectures
2096 ucontext_t *ucontext = (ucontext_t *)context;
2097 *pc = _UC_MACHINE_PC(ucontext);
2098 *bp = _UC_MACHINE_FP(ucontext);
2099 *sp = _UC_MACHINE_SP(ucontext);
2100#elif defined(__arm__)
2101 ucontext_t *ucontext = (ucontext_t*)context;
2102 *pc = ucontext->uc_mcontext.arm_pc;
2103 *bp = ucontext->uc_mcontext.arm_fp;
2104 *sp = ucontext->uc_mcontext.arm_sp;
2105#elif defined(__aarch64__)
2106# if SANITIZER_FREEBSD
2107 ucontext_t *ucontext = (ucontext_t*)context;
2108 *pc = ucontext->uc_mcontext.mc_gpregs.gp_elr;
2109 *bp = ucontext->uc_mcontext.mc_gpregs.gp_x[29];
2110 *sp = ucontext->uc_mcontext.mc_gpregs.gp_sp;
2111# else
2112 ucontext_t *ucontext = (ucontext_t*)context;
2113 *pc = ucontext->uc_mcontext.pc;
2114 *bp = ucontext->uc_mcontext.regs[29];
2115 *sp = ucontext->uc_mcontext.sp;
2116# endif
2117#elif defined(__hppa__)
2118 ucontext_t *ucontext = (ucontext_t*)context;
2119 *pc = ucontext->uc_mcontext.sc_iaoq[0];
2120 /* GCC uses %r3 whenever a frame pointer is needed. */
2121 *bp = ucontext->uc_mcontext.sc_gr[3];
2122 *sp = ucontext->uc_mcontext.sc_gr[30];
2123#elif defined(__x86_64__)
2124# if SANITIZER_FREEBSD
2125 ucontext_t *ucontext = (ucontext_t*)context;
2126 *pc = ucontext->uc_mcontext.mc_rip;
2127 *bp = ucontext->uc_mcontext.mc_rbp;
2128 *sp = ucontext->uc_mcontext.mc_rsp;
2129# else
2130 ucontext_t *ucontext = (ucontext_t*)context;
2131 *pc = ucontext->uc_mcontext.gregs[REG_RIP];
2132 *bp = ucontext->uc_mcontext.gregs[REG_RBP];
2133 *sp = ucontext->uc_mcontext.gregs[REG_RSP];
2134# endif
2135#elif defined(__i386__)
2136# if SANITIZER_FREEBSD
2137 ucontext_t *ucontext = (ucontext_t*)context;
2138 *pc = ucontext->uc_mcontext.mc_eip;
2139 *bp = ucontext->uc_mcontext.mc_ebp;
2140 *sp = ucontext->uc_mcontext.mc_esp;
2141# else
2142 ucontext_t *ucontext = (ucontext_t*)context;
2143# if SANITIZER_SOLARIS
2144 /* Use the numeric values: the symbolic ones are undefined by llvm
2145 include/llvm/Support/Solaris.h. */
2146# ifndef REG_EIP
2147# define REG_EIP 14 // REG_PC
2148# endif
2149# ifndef REG_EBP
2150# define REG_EBP 6 // REG_FP
2151# endif
2152# ifndef REG_UESP
2153# define REG_UESP 17 // REG_SP
2154# endif
2155# endif
2156 *pc = ucontext->uc_mcontext.gregs[REG_EIP];
2157 *bp = ucontext->uc_mcontext.gregs[REG_EBP];
2158 *sp = ucontext->uc_mcontext.gregs[REG_UESP];
2159# endif
2160#elif defined(__powerpc__) || defined(__powerpc64__)
2161# if SANITIZER_FREEBSD
2162 ucontext_t *ucontext = (ucontext_t *)context;
2163 *pc = ucontext->uc_mcontext.mc_srr0;
2164 *sp = ucontext->uc_mcontext.mc_frame[1];
2165 *bp = ucontext->uc_mcontext.mc_frame[31];
2166# else
2167 ucontext_t *ucontext = (ucontext_t*)context;
2168 *pc = ucontext->uc_mcontext.regs->nip;
2169 *sp = ucontext->uc_mcontext.regs->gpr[PT_R1];
2170 // The powerpc{,64}-linux ABIs do not specify r31 as the frame
2171 // pointer, but GCC always uses r31 when we need a frame pointer.
2172 *bp = ucontext->uc_mcontext.regs->gpr[PT_R31];
2173# endif
2174#elif defined(__sparc__)
2175#if defined(__arch64__) || defined(__sparcv9)
2176#define STACK_BIAS 2047
2177#else
2178#define STACK_BIAS 0
2179# endif
2180# if SANITIZER_SOLARIS
2181 ucontext_t *ucontext = (ucontext_t *)context;
2182 *pc = ucontext->uc_mcontext.gregs[REG_PC];
2183 *sp = ucontext->uc_mcontext.gregs[REG_O6] + STACK_BIAS;
2184#else
2185 // Historical BSDism here.
2186 struct sigcontext *scontext = (struct sigcontext *)context;
2187#if defined(__arch64__)
2188 *pc = scontext->sigc_regs.tpc;
2189 *sp = scontext->sigc_regs.u_regs[14] + STACK_BIAS;
2190#else
2191 *pc = scontext->si_regs.pc;
2192 *sp = scontext->si_regs.u_regs[14];
2193#endif
2194# endif
2195 *bp = (uptr)((uhwptr *)*sp)[14] + STACK_BIAS;
2196#elif defined(__mips__)
2197 ucontext_t *ucontext = (ucontext_t*)context;
2198 *pc = ucontext->uc_mcontext.pc;
2199 *bp = ucontext->uc_mcontext.gregs[30];
2200 *sp = ucontext->uc_mcontext.gregs[29];
2201#elif defined(__s390__)
2202 ucontext_t *ucontext = (ucontext_t*)context;
2203# if defined(__s390x__)
2204 *pc = ucontext->uc_mcontext.psw.addr;
2205# else
2206 *pc = ucontext->uc_mcontext.psw.addr & 0x7fffffff;
2207# endif
2208 *bp = ucontext->uc_mcontext.gregs[11];
2209 *sp = ucontext->uc_mcontext.gregs[15];
2210#elif defined(__riscv)
2211 ucontext_t *ucontext = (ucontext_t*)context;
2212# if SANITIZER_FREEBSD
2213 *pc = ucontext->uc_mcontext.mc_gpregs.gp_sepc;
2214 *bp = ucontext->uc_mcontext.mc_gpregs.gp_s[0];
2215 *sp = ucontext->uc_mcontext.mc_gpregs.gp_sp;
2216# else
2217 *pc = ucontext->uc_mcontext.__gregs[REG_PC];
2218 *bp = ucontext->uc_mcontext.__gregs[REG_S0];
2219 *sp = ucontext->uc_mcontext.__gregs[REG_SP];
2220# endif
2221# elif defined(__hexagon__)
2222 ucontext_t *ucontext = (ucontext_t *)context;
2223 *pc = ucontext->uc_mcontext.pc;
2224 *bp = ucontext->uc_mcontext.r30;
2225 *sp = ucontext->uc_mcontext.r29;
2226# elif defined(__loongarch__)
2227 ucontext_t *ucontext = (ucontext_t *)context;
2228 *pc = ucontext->uc_mcontext.__pc;
2229 *bp = ucontext->uc_mcontext.__gregs[22];
2230 *sp = ucontext->uc_mcontext.__gregs[3];
2231# else
2232# error "Unsupported arch"
2233# endif
2234}
2235
2236void SignalContext::InitPcSpBp() { GetPcSpBp(context, &pc, &sp, &bp); }
2237
2238void InitializePlatformEarly() {
2239 // Do nothing.
2240}
2241
2242void CheckASLR() {
2243#if SANITIZER_NETBSD
2244 int mib[3];
2245 int paxflags;
2246 uptr len = sizeof(paxflags);
2247
2248 mib[0] = CTL_PROC;
2249 mib[1] = internal_getpid();
2250 mib[2] = PROC_PID_PAXFLAGS;
2251
2252 if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2253 Printf("sysctl failed\n");
2254 Die();
2255 }
2256
2257 if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_ASLR)) {
2258 Printf("This sanitizer is not compatible with enabled ASLR.\n"
2259 "To disable ASLR, please run \"paxctl +a %s\" and try again.\n",
2260 GetArgv()[0]);
2261 Die();
2262 }
2263#elif SANITIZER_FREEBSD
2264 int aslr_status;
2265 int r = internal_procctl(P_PID, 0, PROC_ASLR_STATUS, &aslr_status);
2266 if (UNLIKELY(r == -1)) {
2267 // We're making things less 'dramatic' here since
2268 // the cmd is not necessarily guaranteed to be here
2269 // just yet regarding FreeBSD release
2270 return;
2271 }
2272 if ((aslr_status & PROC_ASLR_ACTIVE) != 0) {
2273 Printf("This sanitizer is not compatible with enabled ASLR "
2274 "and binaries compiled with PIE\n");
2275 Die();
2276 }
2277# elif SANITIZER_PPC64V2
2278 // Disable ASLR for Linux PPC64LE.
2279 int old_personality = personality(0xffffffff);
2280 if (old_personality != -1 && (old_personality & ADDR_NO_RANDOMIZE) == 0) {
2281 VReport(1,
2282 "WARNING: Program is being run with address space layout "
2283 "randomization (ASLR) enabled which prevents the thread and "
2284 "memory sanitizers from working on powerpc64le.\n"
2285 "ASLR will be disabled and the program re-executed.\n");
2286 CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
2287 ReExec();
2288 }
2289# else
2290 // Do nothing
2291# endif
2292}
2293
2294void CheckMPROTECT() {
2295#if SANITIZER_NETBSD
2296 int mib[3];
2297 int paxflags;
2298 uptr len = sizeof(paxflags);
2299
2300 mib[0] = CTL_PROC;
2301 mib[1] = internal_getpid();
2302 mib[2] = PROC_PID_PAXFLAGS;
2303
2304 if (UNLIKELY(internal_sysctl(mib, 3, &paxflags, &len, NULL, 0) == -1)) {
2305 Printf("sysctl failed\n");
2306 Die();
2307 }
2308
2309 if (UNLIKELY(paxflags & CTL_PROC_PAXFLAGS_MPROTECT)) {
2310 Printf("This sanitizer is not compatible with enabled MPROTECT\n");
2311 Die();
2312 }
2313#else
2314 // Do nothing
2315#endif
2316}
2317
2318void CheckNoDeepBind(const char *filename, int flag) {
2319#ifdef RTLD_DEEPBIND
2320 if (flag & RTLD_DEEPBIND) {
2321 Report(
2322 "You are trying to dlopen a %s shared library with RTLD_DEEPBIND flag"
2323 " which is incompatible with sanitizer runtime "
2324 "(see https://github.com/google/sanitizers/issues/611 for details"
2325 "). If you want to run %s library under sanitizers please remove "
2326 "RTLD_DEEPBIND from dlopen flags.\n",
2327 filename, filename);
2328 Die();
2329 }
2330#endif
2331}
2332
2333uptr FindAvailableMemoryRange(uptr size, uptr alignment, uptr left_padding,
2334 uptr *largest_gap_found,
2335 uptr *max_occupied_addr) {
2336 UNREACHABLE("FindAvailableMemoryRange is not available");
2337 return 0;
2338}
2339
2340bool GetRandom(void *buffer, uptr length, bool blocking) {
2341 if (!buffer || !length || length > 256)
2342 return false;
2343#if SANITIZER_USE_GETENTROPY
2344 uptr rnd = getentropy(buffer, length);
2345 int rverrno = 0;
2346 if (internal_iserror(rnd, &rverrno) && rverrno == EFAULT)
2347 return false;
2348 else if (rnd == 0)
2349 return true;
2350#endif // SANITIZER_USE_GETENTROPY
2351
2352#if SANITIZER_USE_GETRANDOM
2353 static atomic_uint8_t skip_getrandom_syscall;
2354 if (!atomic_load_relaxed(&skip_getrandom_syscall)) {
2355 // Up to 256 bytes, getrandom will not be interrupted.
2356 uptr res = internal_syscall(SYSCALL(getrandom), buffer, length,
2357 blocking ? 0 : GRND_NONBLOCK);
2358 int rverrno = 0;
2359 if (internal_iserror(res, &rverrno) && rverrno == ENOSYS)
2360 atomic_store_relaxed(&skip_getrandom_syscall, 1);
2361 else if (res == length)
2362 return true;
2363 }
2364#endif // SANITIZER_USE_GETRANDOM
2365 // Up to 256 bytes, a read off /dev/urandom will not be interrupted.
2366 // blocking is moot here, O_NONBLOCK has no effect when opening /dev/urandom.
2367 uptr fd = internal_open("/dev/urandom", O_RDONLY);
2368 if (internal_iserror(fd))
2369 return false;
2370 uptr res = internal_read(fd, buffer, length);
2371 if (internal_iserror(res))
2372 return false;
2373 internal_close(fd);
2374 return true;
2375}
2376
2377} // namespace __sanitizer
2378
2379#endif
2380

source code of compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp