1 //===-- sanitizer_linux_libcdep.cc ----------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is shared between AddressSanitizer and ThreadSanitizer
11 // run-time libraries and implements linux-specific functions from
12 // sanitizer_libc.h.
13 //===----------------------------------------------------------------------===//
14
15 #include "sanitizer_platform.h"
16
17 #if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
18 SANITIZER_OPENBSD || SANITIZER_SOLARIS
19
20 #include "sanitizer_allocator_internal.h"
21 #include "sanitizer_atomic.h"
22 #include "sanitizer_common.h"
23 #include "sanitizer_file.h"
24 #include "sanitizer_flags.h"
25 #include "sanitizer_freebsd.h"
26 #include "sanitizer_getauxval.h"
27 #include "sanitizer_linux.h"
28 #include "sanitizer_placement_new.h"
29 #include "sanitizer_procmaps.h"
30
31 #include <dlfcn.h> // for dlsym()
32 #include <link.h>
33 #include <pthread.h>
34 #include <signal.h>
35 #include <sys/resource.h>
36 #include <syslog.h>
37
38 #if SANITIZER_FREEBSD
39 #include <pthread_np.h>
40 #include <osreldate.h>
41 #include <sys/sysctl.h>
42 #define pthread_getattr_np pthread_attr_get_np
43 #endif
44
45 #if SANITIZER_OPENBSD
46 #include <pthread_np.h>
47 #include <sys/sysctl.h>
48 #endif
49
50 #if SANITIZER_NETBSD
51 #include <sys/sysctl.h>
52 #include <sys/tls.h>
53 #endif
54
55 #if SANITIZER_SOLARIS
56 #include <thread.h>
57 #endif
58
59 #if SANITIZER_ANDROID
60 #include <android/api-level.h>
61 #if !defined(CPU_COUNT) && !defined(__aarch64__)
62 #include <dirent.h>
63 #include <fcntl.h>
64 struct __sanitizer::linux_dirent {
65 long d_ino;
66 off_t d_off;
67 unsigned short d_reclen;
68 char d_name[];
69 };
70 #endif
71 #endif
72
73 #if !SANITIZER_ANDROID
74 #include <elf.h>
75 #include <unistd.h>
76 #endif
77
78 namespace __sanitizer {
79
80 SANITIZER_WEAK_ATTRIBUTE int
81 real_sigaction(int signum, const void *act, void *oldact);
82
internal_sigaction(int signum,const void * act,void * oldact)83 int internal_sigaction(int signum, const void *act, void *oldact) {
84 #if !SANITIZER_GO
85 if (&real_sigaction)
86 return real_sigaction(signum, act, oldact);
87 #endif
88 return sigaction(signum, (const struct sigaction *)act,
89 (struct sigaction *)oldact);
90 }
91
GetThreadStackTopAndBottom(bool at_initialization,uptr * stack_top,uptr * stack_bottom)92 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
93 uptr *stack_bottom) {
94 CHECK(stack_top);
95 CHECK(stack_bottom);
96 if (at_initialization) {
97 // This is the main thread. Libpthread may not be initialized yet.
98 struct rlimit rl;
99 CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
100
101 // Find the mapping that contains a stack variable.
102 MemoryMappingLayout proc_maps(/*cache_enabled*/true);
103 if (proc_maps.Error()) {
104 *stack_top = *stack_bottom = 0;
105 return;
106 }
107 MemoryMappedSegment segment;
108 uptr prev_end = 0;
109 while (proc_maps.Next(&segment)) {
110 if ((uptr)&rl < segment.end) break;
111 prev_end = segment.end;
112 }
113 CHECK((uptr)&rl >= segment.start && (uptr)&rl < segment.end);
114
115 // Get stacksize from rlimit, but clip it so that it does not overlap
116 // with other mappings.
117 uptr stacksize = rl.rlim_cur;
118 if (stacksize > segment.end - prev_end) stacksize = segment.end - prev_end;
119 // When running with unlimited stack size, we still want to set some limit.
120 // The unlimited stack size is caused by 'ulimit -s unlimited'.
121 // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
122 if (stacksize > kMaxThreadStackSize)
123 stacksize = kMaxThreadStackSize;
124 *stack_top = segment.end;
125 *stack_bottom = segment.end - stacksize;
126 return;
127 }
128 uptr stacksize = 0;
129 void *stackaddr = nullptr;
130 #if SANITIZER_SOLARIS
131 stack_t ss;
132 CHECK_EQ(thr_stksegment(&ss), 0);
133 stacksize = ss.ss_size;
134 stackaddr = (char *)ss.ss_sp - stacksize;
135 #elif SANITIZER_OPENBSD
136 stack_t sattr;
137 CHECK_EQ(pthread_stackseg_np(pthread_self(), &sattr), 0);
138 stackaddr = sattr.ss_sp;
139 stacksize = sattr.ss_size;
140 #else // !SANITIZER_SOLARIS
141 pthread_attr_t attr;
142 pthread_attr_init(&attr);
143 CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
144 my_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
145 pthread_attr_destroy(&attr);
146 #endif // SANITIZER_SOLARIS
147
148 *stack_top = (uptr)stackaddr + stacksize;
149 *stack_bottom = (uptr)stackaddr;
150 }
151
152 #if !SANITIZER_GO
SetEnv(const char * name,const char * value)153 bool SetEnv(const char *name, const char *value) {
154 void *f = dlsym(RTLD_NEXT, "setenv");
155 if (!f)
156 return false;
157 typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
158 setenv_ft setenv_f;
159 CHECK_EQ(sizeof(setenv_f), sizeof(f));
160 internal_memcpy(&setenv_f, &f, sizeof(f));
161 return setenv_f(name, value, 1) == 0;
162 }
163 #endif
164
GetLibcVersion(int * major,int * minor,int * patch)165 __attribute__((unused)) static bool GetLibcVersion(int *major, int *minor,
166 int *patch) {
167 #ifdef _CS_GNU_LIBC_VERSION
168 char buf[64];
169 uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
170 if (len >= sizeof(buf))
171 return false;
172 buf[len] = 0;
173 static const char kGLibC[] = "glibc ";
174 if (internal_strncmp(buf, kGLibC, sizeof(kGLibC) - 1) != 0)
175 return false;
176 const char *p = buf + sizeof(kGLibC) - 1;
177 *major = internal_simple_strtoll(p, &p, 10);
178 *minor = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
179 *patch = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
180 return true;
181 #else
182 return false;
183 #endif
184 }
185
186 #if !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO && \
187 !SANITIZER_NETBSD && !SANITIZER_OPENBSD && !SANITIZER_SOLARIS
188 static uptr g_tls_size;
189
190 #ifdef __i386__
191 # ifndef __GLIBC_PREREQ
192 # define CHECK_GET_TLS_STATIC_INFO_VERSION 1
193 # else
194 # define CHECK_GET_TLS_STATIC_INFO_VERSION (!__GLIBC_PREREQ(2, 27))
195 # endif
196 #else
197 # define CHECK_GET_TLS_STATIC_INFO_VERSION 0
198 #endif
199
200 #if CHECK_GET_TLS_STATIC_INFO_VERSION
201 # define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
202 #else
203 # define DL_INTERNAL_FUNCTION
204 #endif
205
206 namespace {
207 struct GetTlsStaticInfoCall {
208 typedef void (*get_tls_func)(size_t*, size_t*);
209 };
210 struct GetTlsStaticInfoRegparmCall {
211 typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
212 };
213
214 template <typename T>
CallGetTls(void * ptr,size_t * size,size_t * align)215 void CallGetTls(void* ptr, size_t* size, size_t* align) {
216 typename T::get_tls_func get_tls;
217 CHECK_EQ(sizeof(get_tls), sizeof(ptr));
218 internal_memcpy(&get_tls, &ptr, sizeof(ptr));
219 CHECK_NE(get_tls, 0);
220 get_tls(size, align);
221 }
222
CmpLibcVersion(int major,int minor,int patch)223 bool CmpLibcVersion(int major, int minor, int patch) {
224 int ma;
225 int mi;
226 int pa;
227 if (!GetLibcVersion(&ma, &mi, &pa))
228 return false;
229 if (ma > major)
230 return true;
231 if (ma < major)
232 return false;
233 if (mi > minor)
234 return true;
235 if (mi < minor)
236 return false;
237 return pa >= patch;
238 }
239
240 } // namespace
241
InitTlsSize()242 void InitTlsSize() {
243 // all current supported platforms have 16 bytes stack alignment
244 const size_t kStackAlign = 16;
245 void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
246 size_t tls_size = 0;
247 size_t tls_align = 0;
248 // On i?86, _dl_get_tls_static_info used to be internal_function, i.e.
249 // __attribute__((regparm(3), stdcall)) before glibc 2.27 and is normal
250 // function in 2.27 and later.
251 if (CHECK_GET_TLS_STATIC_INFO_VERSION && !CmpLibcVersion(2, 27, 0))
252 CallGetTls<GetTlsStaticInfoRegparmCall>(get_tls_static_info_ptr,
253 &tls_size, &tls_align);
254 else
255 CallGetTls<GetTlsStaticInfoCall>(get_tls_static_info_ptr,
256 &tls_size, &tls_align);
257 if (tls_align < kStackAlign)
258 tls_align = kStackAlign;
259 g_tls_size = RoundUpTo(tls_size, tls_align);
260 }
261 #else
InitTlsSize()262 void InitTlsSize() { }
263 #endif // !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO &&
264 // !SANITIZER_NETBSD && !SANITIZER_SOLARIS
265
266 #if (defined(__x86_64__) || defined(__i386__) || defined(__mips__) || \
267 defined(__aarch64__) || defined(__powerpc64__) || defined(__s390__) || \
268 defined(__arm__)) && \
269 SANITIZER_LINUX && !SANITIZER_ANDROID
270 // sizeof(struct pthread) from glibc.
271 static atomic_uintptr_t thread_descriptor_size;
272
ThreadDescriptorSize()273 uptr ThreadDescriptorSize() {
274 uptr val = atomic_load_relaxed(&thread_descriptor_size);
275 if (val)
276 return val;
277 #if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
278 int major;
279 int minor;
280 int patch;
281 if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
282 /* sizeof(struct pthread) values from various glibc versions. */
283 if (SANITIZER_X32)
284 val = 1728; // Assume only one particular version for x32.
285 // For ARM sizeof(struct pthread) changed in Glibc 2.23.
286 else if (SANITIZER_ARM)
287 val = minor <= 22 ? 1120 : 1216;
288 else if (minor <= 3)
289 val = FIRST_32_SECOND_64(1104, 1696);
290 else if (minor == 4)
291 val = FIRST_32_SECOND_64(1120, 1728);
292 else if (minor == 5)
293 val = FIRST_32_SECOND_64(1136, 1728);
294 else if (minor <= 9)
295 val = FIRST_32_SECOND_64(1136, 1712);
296 else if (minor == 10)
297 val = FIRST_32_SECOND_64(1168, 1776);
298 else if (minor == 11 || (minor == 12 && patch == 1))
299 val = FIRST_32_SECOND_64(1168, 2288);
300 else if (minor <= 14)
301 val = FIRST_32_SECOND_64(1168, 2304);
302 else
303 val = FIRST_32_SECOND_64(1216, 2304);
304 }
305 #elif defined(__mips__)
306 // TODO(sagarthakur): add more values as per different glibc versions.
307 val = FIRST_32_SECOND_64(1152, 1776);
308 #elif defined(__aarch64__)
309 // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
310 val = 1776;
311 #elif defined(__powerpc64__)
312 val = 1776; // from glibc.ppc64le 2.20-8.fc21
313 #elif defined(__s390__)
314 val = FIRST_32_SECOND_64(1152, 1776); // valid for glibc 2.22
315 #endif
316 if (val)
317 atomic_store_relaxed(&thread_descriptor_size, val);
318 return val;
319 }
320
321 // The offset at which pointer to self is located in the thread descriptor.
322 const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
323
ThreadSelfOffset()324 uptr ThreadSelfOffset() {
325 return kThreadSelfOffset;
326 }
327
328 #if defined(__mips__) || defined(__powerpc64__)
329 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb
330 // head structure. It lies before the static tls blocks.
TlsPreTcbSize()331 static uptr TlsPreTcbSize() {
332 # if defined(__mips__)
333 const uptr kTcbHead = 16; // sizeof (tcbhead_t)
334 # elif defined(__powerpc64__)
335 const uptr kTcbHead = 88; // sizeof (tcbhead_t)
336 # endif
337 const uptr kTlsAlign = 16;
338 const uptr kTlsPreTcbSize =
339 RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign);
340 return kTlsPreTcbSize;
341 }
342 #endif
343
ThreadSelf()344 uptr ThreadSelf() {
345 uptr descr_addr;
346 # if defined(__i386__)
347 asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
348 # elif defined(__x86_64__)
349 asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
350 # elif defined(__mips__)
351 // MIPS uses TLS variant I. The thread pointer (in hardware register $29)
352 // points to the end of the TCB + 0x7000. The pthread_descr structure is
353 // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
354 // TCB and the size of pthread_descr.
355 const uptr kTlsTcbOffset = 0x7000;
356 uptr thread_pointer;
357 asm volatile(".set push;\
358 .set mips64r2;\
359 rdhwr %0,$29;\
360 .set pop" : "=r" (thread_pointer));
361 descr_addr = thread_pointer - kTlsTcbOffset - TlsPreTcbSize();
362 # elif defined(__aarch64__) || defined(__arm__)
363 descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
364 ThreadDescriptorSize();
365 # elif defined(__s390__)
366 descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer());
367 # elif defined(__powerpc64__)
368 // PPC64LE uses TLS variant I. The thread pointer (in GPR 13)
369 // points to the end of the TCB + 0x7000. The pthread_descr structure is
370 // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
371 // TCB and the size of pthread_descr.
372 const uptr kTlsTcbOffset = 0x7000;
373 uptr thread_pointer;
374 asm("addi %0,13,%1" : "=r"(thread_pointer) : "I"(-kTlsTcbOffset));
375 descr_addr = thread_pointer - TlsPreTcbSize();
376 # else
377 # error "unsupported CPU arch"
378 # endif
379 return descr_addr;
380 }
381 #endif // (x86_64 || i386 || MIPS) && SANITIZER_LINUX
382
383 #if SANITIZER_FREEBSD
ThreadSelfSegbase()384 static void **ThreadSelfSegbase() {
385 void **segbase = 0;
386 # if defined(__i386__)
387 // sysarch(I386_GET_GSBASE, segbase);
388 __asm __volatile("mov %%gs:0, %0" : "=r" (segbase));
389 # elif defined(__x86_64__)
390 // sysarch(AMD64_GET_FSBASE, segbase);
391 __asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
392 # else
393 # error "unsupported CPU arch"
394 # endif
395 return segbase;
396 }
397
ThreadSelf()398 uptr ThreadSelf() {
399 return (uptr)ThreadSelfSegbase()[2];
400 }
401 #endif // SANITIZER_FREEBSD
402
403 #if SANITIZER_NETBSD
ThreadSelfTlsTcb()404 static struct tls_tcb * ThreadSelfTlsTcb() {
405 struct tls_tcb * tcb;
406 # ifdef __HAVE___LWP_GETTCB_FAST
407 tcb = (struct tls_tcb *)__lwp_gettcb_fast();
408 # elif defined(__HAVE___LWP_GETPRIVATE_FAST)
409 tcb = (struct tls_tcb *)__lwp_getprivate_fast();
410 # endif
411 return tcb;
412 }
413
ThreadSelf()414 uptr ThreadSelf() {
415 return (uptr)ThreadSelfTlsTcb()->tcb_pthread;
416 }
417
GetSizeFromHdr(struct dl_phdr_info * info,size_t size,void * data)418 int GetSizeFromHdr(struct dl_phdr_info *info, size_t size, void *data) {
419 const Elf_Phdr *hdr = info->dlpi_phdr;
420 const Elf_Phdr *last_hdr = hdr + info->dlpi_phnum;
421
422 for (; hdr != last_hdr; ++hdr) {
423 if (hdr->p_type == PT_TLS && info->dlpi_tls_modid == 1) {
424 *(uptr*)data = hdr->p_memsz;
425 break;
426 }
427 }
428 return 0;
429 }
430 #endif // SANITIZER_NETBSD
431
432 #if !SANITIZER_GO
GetTls(uptr * addr,uptr * size)433 static void GetTls(uptr *addr, uptr *size) {
434 #if SANITIZER_LINUX && !SANITIZER_ANDROID
435 # if defined(__x86_64__) || defined(__i386__) || defined(__s390__)
436 *addr = ThreadSelf();
437 *size = GetTlsSize();
438 *addr -= *size;
439 *addr += ThreadDescriptorSize();
440 # elif defined(__mips__) || defined(__aarch64__) || defined(__powerpc64__) \
441 || defined(__arm__)
442 *addr = ThreadSelf();
443 *size = GetTlsSize();
444 # else
445 *addr = 0;
446 *size = 0;
447 # endif
448 #elif SANITIZER_FREEBSD
449 void** segbase = ThreadSelfSegbase();
450 *addr = 0;
451 *size = 0;
452 if (segbase != 0) {
453 // tcbalign = 16
454 // tls_size = round(tls_static_space, tcbalign);
455 // dtv = segbase[1];
456 // dtv[2] = segbase - tls_static_space;
457 void **dtv = (void**) segbase[1];
458 *addr = (uptr) dtv[2];
459 *size = (*addr == 0) ? 0 : ((uptr) segbase[0] - (uptr) dtv[2]);
460 }
461 #elif SANITIZER_NETBSD
462 struct tls_tcb * const tcb = ThreadSelfTlsTcb();
463 *addr = 0;
464 *size = 0;
465 if (tcb != 0) {
466 // Find size (p_memsz) of dlpi_tls_modid 1 (TLS block of the main program).
467 // ld.elf_so hardcodes the index 1.
468 dl_iterate_phdr(GetSizeFromHdr, size);
469
470 if (*size != 0) {
471 // The block has been found and tcb_dtv[1] contains the base address
472 *addr = (uptr)tcb->tcb_dtv[1];
473 }
474 }
475 #elif SANITIZER_OPENBSD
476 *addr = 0;
477 *size = 0;
478 #elif SANITIZER_ANDROID
479 *addr = 0;
480 *size = 0;
481 #elif SANITIZER_SOLARIS
482 // FIXME
483 *addr = 0;
484 *size = 0;
485 #else
486 # error "Unknown OS"
487 #endif
488 }
489 #endif
490
491 #if !SANITIZER_GO
GetTlsSize()492 uptr GetTlsSize() {
493 #if SANITIZER_FREEBSD || SANITIZER_ANDROID || SANITIZER_NETBSD || \
494 SANITIZER_OPENBSD || SANITIZER_SOLARIS
495 uptr addr, size;
496 GetTls(&addr, &size);
497 return size;
498 #elif defined(__mips__) || defined(__powerpc64__)
499 return RoundUpTo(g_tls_size + TlsPreTcbSize(), 16);
500 #else
501 return g_tls_size;
502 #endif
503 }
504 #endif
505
GetThreadStackAndTls(bool main,uptr * stk_addr,uptr * stk_size,uptr * tls_addr,uptr * tls_size)506 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
507 uptr *tls_addr, uptr *tls_size) {
508 #if SANITIZER_GO
509 // Stub implementation for Go.
510 *stk_addr = *stk_size = *tls_addr = *tls_size = 0;
511 #else
512 GetTls(tls_addr, tls_size);
513
514 uptr stack_top, stack_bottom;
515 GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
516 *stk_addr = stack_bottom;
517 *stk_size = stack_top - stack_bottom;
518
519 if (!main) {
520 // If stack and tls intersect, make them non-intersecting.
521 if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
522 CHECK_GT(*tls_addr + *tls_size, *stk_addr);
523 CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
524 *stk_size -= *tls_size;
525 *tls_addr = *stk_addr + *stk_size;
526 }
527 }
528 #endif
529 }
530
531 #if !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
532 typedef ElfW(Phdr) Elf_Phdr;
533 #elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001 // v9.2
534 #define Elf_Phdr XElf32_Phdr
535 #define dl_phdr_info xdl_phdr_info
536 #define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
537 #endif // !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
538
539 struct DlIteratePhdrData {
540 InternalMmapVectorNoCtor<LoadedModule> *modules;
541 bool first;
542 };
543
dl_iterate_phdr_cb(dl_phdr_info * info,size_t size,void * arg)544 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
545 DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
546 InternalScopedString module_name(kMaxPathLength);
547 if (data->first) {
548 data->first = false;
549 // First module is the binary itself.
550 ReadBinaryNameCached(module_name.data(), module_name.size());
551 } else if (info->dlpi_name) {
552 module_name.append("%s", info->dlpi_name);
553 }
554 if (module_name[0] == '\0')
555 return 0;
556 LoadedModule cur_module;
557 cur_module.set(module_name.data(), info->dlpi_addr);
558 for (int i = 0; i < (int)info->dlpi_phnum; i++) {
559 const Elf_Phdr *phdr = &info->dlpi_phdr[i];
560 if (phdr->p_type == PT_LOAD) {
561 uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
562 uptr cur_end = cur_beg + phdr->p_memsz;
563 bool executable = phdr->p_flags & PF_X;
564 bool writable = phdr->p_flags & PF_W;
565 cur_module.addAddressRange(cur_beg, cur_end, executable,
566 writable);
567 }
568 }
569 data->modules->push_back(cur_module);
570 return 0;
571 }
572
573 #if SANITIZER_ANDROID && __ANDROID_API__ < 21
574 extern "C" __attribute__((weak)) int dl_iterate_phdr(
575 int (*)(struct dl_phdr_info *, size_t, void *), void *);
576 #endif
577
requiresProcmaps()578 static bool requiresProcmaps() {
579 #if SANITIZER_ANDROID && __ANDROID_API__ <= 22
580 // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
581 // The runtime check allows the same library to work with
582 // both K and L (and future) Android releases.
583 return AndroidGetApiLevel() <= ANDROID_LOLLIPOP_MR1;
584 #else
585 return false;
586 #endif
587 }
588
procmapsInit(InternalMmapVectorNoCtor<LoadedModule> * modules)589 static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) {
590 MemoryMappingLayout memory_mapping(/*cache_enabled*/true);
591 memory_mapping.DumpListOfModules(modules);
592 }
593
init()594 void ListOfModules::init() {
595 clearOrInit();
596 if (requiresProcmaps()) {
597 procmapsInit(&modules_);
598 } else {
599 DlIteratePhdrData data = {&modules_, true};
600 dl_iterate_phdr(dl_iterate_phdr_cb, &data);
601 }
602 }
603
604 // When a custom loader is used, dl_iterate_phdr may not contain the full
605 // list of modules. Allow callers to fall back to using procmaps.
fallbackInit()606 void ListOfModules::fallbackInit() {
607 if (!requiresProcmaps()) {
608 clearOrInit();
609 procmapsInit(&modules_);
610 } else {
611 clear();
612 }
613 }
614
615 // getrusage does not give us the current RSS, only the max RSS.
616 // Still, this is better than nothing if /proc/self/statm is not available
617 // for some reason, e.g. due to a sandbox.
GetRSSFromGetrusage()618 static uptr GetRSSFromGetrusage() {
619 struct rusage usage;
620 if (getrusage(RUSAGE_SELF, &usage)) // Failed, probably due to a sandbox.
621 return 0;
622 return usage.ru_maxrss << 10; // ru_maxrss is in Kb.
623 }
624
GetRSS()625 uptr GetRSS() {
626 if (!common_flags()->can_use_proc_maps_statm)
627 return GetRSSFromGetrusage();
628 fd_t fd = OpenFile("/proc/self/statm", RdOnly);
629 if (fd == kInvalidFd)
630 return GetRSSFromGetrusage();
631 char buf[64];
632 uptr len = internal_read(fd, buf, sizeof(buf) - 1);
633 internal_close(fd);
634 if ((sptr)len <= 0)
635 return 0;
636 buf[len] = 0;
637 // The format of the file is:
638 // 1084 89 69 11 0 79 0
639 // We need the second number which is RSS in pages.
640 char *pos = buf;
641 // Skip the first number.
642 while (*pos >= '0' && *pos <= '9')
643 pos++;
644 // Skip whitespaces.
645 while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
646 pos++;
647 // Read the number.
648 uptr rss = 0;
649 while (*pos >= '0' && *pos <= '9')
650 rss = rss * 10 + *pos++ - '0';
651 return rss * GetPageSizeCached();
652 }
653
654 // sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used on most platforms as
655 // they allocate memory.
GetNumberOfCPUs()656 u32 GetNumberOfCPUs() {
657 #if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD
658 u32 ncpu;
659 int req[2];
660 uptr len = sizeof(ncpu);
661 req[0] = CTL_HW;
662 req[1] = HW_NCPU;
663 CHECK_EQ(internal_sysctl(req, 2, &ncpu, &len, NULL, 0), 0);
664 return ncpu;
665 #elif SANITIZER_ANDROID && !defined(CPU_COUNT) && !defined(__aarch64__)
666 // Fall back to /sys/devices/system/cpu on Android when cpu_set_t doesn't
667 // exist in sched.h. That is the case for toolchains generated with older
668 // NDKs.
669 // This code doesn't work on AArch64 because internal_getdents makes use of
670 // the 64bit getdents syscall, but cpu_set_t seems to always exist on AArch64.
671 uptr fd = internal_open("/sys/devices/system/cpu", O_RDONLY | O_DIRECTORY);
672 if (internal_iserror(fd))
673 return 0;
674 InternalMmapVector<u8> buffer(4096);
675 uptr bytes_read = buffer.size();
676 uptr n_cpus = 0;
677 u8 *d_type;
678 struct linux_dirent *entry = (struct linux_dirent *)&buffer[bytes_read];
679 while (true) {
680 if ((u8 *)entry >= &buffer[bytes_read]) {
681 bytes_read = internal_getdents(fd, (struct linux_dirent *)buffer.data(),
682 buffer.size());
683 if (internal_iserror(bytes_read) || !bytes_read)
684 break;
685 entry = (struct linux_dirent *)buffer.data();
686 }
687 d_type = (u8 *)entry + entry->d_reclen - 1;
688 if (d_type >= &buffer[bytes_read] ||
689 (u8 *)&entry->d_name[3] >= &buffer[bytes_read])
690 break;
691 if (entry->d_ino != 0 && *d_type == DT_DIR) {
692 if (entry->d_name[0] == 'c' && entry->d_name[1] == 'p' &&
693 entry->d_name[2] == 'u' &&
694 entry->d_name[3] >= '0' && entry->d_name[3] <= '9')
695 n_cpus++;
696 }
697 entry = (struct linux_dirent *)(((u8 *)entry) + entry->d_reclen);
698 }
699 internal_close(fd);
700 return n_cpus;
701 #elif SANITIZER_SOLARIS
702 return sysconf(_SC_NPROCESSORS_ONLN);
703 #else
704 cpu_set_t CPUs;
705 CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
706 return CPU_COUNT(&CPUs);
707 #endif
708 }
709
710 #if SANITIZER_LINUX
711
712 # if SANITIZER_ANDROID
713 static atomic_uint8_t android_log_initialized;
714
AndroidLogInit()715 void AndroidLogInit() {
716 openlog(GetProcessName(), 0, LOG_USER);
717 atomic_store(&android_log_initialized, 1, memory_order_release);
718 }
719
ShouldLogAfterPrintf()720 static bool ShouldLogAfterPrintf() {
721 return atomic_load(&android_log_initialized, memory_order_acquire);
722 }
723
724 extern "C" SANITIZER_WEAK_ATTRIBUTE
725 int async_safe_write_log(int pri, const char* tag, const char* msg);
726 extern "C" SANITIZER_WEAK_ATTRIBUTE
727 int __android_log_write(int prio, const char* tag, const char* msg);
728
729 // ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
730 #define SANITIZER_ANDROID_LOG_INFO 4
731
732 // async_safe_write_log is a new public version of __libc_write_log that is
733 // used behind syslog. It is preferable to syslog as it will not do any dynamic
734 // memory allocation or formatting.
735 // If the function is not available, syslog is preferred for L+ (it was broken
736 // pre-L) as __android_log_write triggers a racey behavior with the strncpy
737 // interceptor. Fallback to __android_log_write pre-L.
WriteOneLineToSyslog(const char * s)738 void WriteOneLineToSyslog(const char *s) {
739 if (&async_safe_write_log) {
740 async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
741 } else if (AndroidGetApiLevel() > ANDROID_KITKAT) {
742 syslog(LOG_INFO, "%s", s);
743 } else {
744 CHECK(&__android_log_write);
745 __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
746 }
747 }
748
749 extern "C" SANITIZER_WEAK_ATTRIBUTE
750 void android_set_abort_message(const char *);
751
SetAbortMessage(const char * str)752 void SetAbortMessage(const char *str) {
753 if (&android_set_abort_message)
754 android_set_abort_message(str);
755 }
756 # else
AndroidLogInit()757 void AndroidLogInit() {}
758
ShouldLogAfterPrintf()759 static bool ShouldLogAfterPrintf() { return true; }
760
WriteOneLineToSyslog(const char * s)761 void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
762
SetAbortMessage(const char * str)763 void SetAbortMessage(const char *str) {}
764 # endif // SANITIZER_ANDROID
765
LogMessageOnPrintf(const char * str)766 void LogMessageOnPrintf(const char *str) {
767 if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
768 WriteToSyslog(str);
769 }
770
771 #endif // SANITIZER_LINUX
772
773 #if SANITIZER_LINUX && !SANITIZER_GO
774 // glibc crashes when using clock_gettime from a preinit_array function as the
775 // vDSO function pointers haven't been initialized yet. __progname is
776 // initialized after the vDSO function pointers, so if it exists, is not null
777 // and is not empty, we can use clock_gettime.
778 extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname;
CanUseVDSO()779 INLINE bool CanUseVDSO() {
780 // Bionic is safe, it checks for the vDSO function pointers to be initialized.
781 if (SANITIZER_ANDROID)
782 return true;
783 if (&__progname && __progname && *__progname)
784 return true;
785 return false;
786 }
787
788 // MonotonicNanoTime is a timing function that can leverage the vDSO by calling
789 // clock_gettime. real_clock_gettime only exists if clock_gettime is
790 // intercepted, so define it weakly and use it if available.
791 extern "C" SANITIZER_WEAK_ATTRIBUTE
792 int real_clock_gettime(u32 clk_id, void *tp);
MonotonicNanoTime()793 u64 MonotonicNanoTime() {
794 timespec ts;
795 if (CanUseVDSO()) {
796 if (&real_clock_gettime)
797 real_clock_gettime(CLOCK_MONOTONIC, &ts);
798 else
799 clock_gettime(CLOCK_MONOTONIC, &ts);
800 } else {
801 internal_clock_gettime(CLOCK_MONOTONIC, &ts);
802 }
803 return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
804 }
805 #else
806 // Non-Linux & Go always use the syscall.
MonotonicNanoTime()807 u64 MonotonicNanoTime() {
808 timespec ts;
809 internal_clock_gettime(CLOCK_MONOTONIC, &ts);
810 return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
811 }
812 #endif // SANITIZER_LINUX && !SANITIZER_GO
813
814 #if !SANITIZER_OPENBSD
ReExec()815 void ReExec() {
816 const char *pathname = "/proc/self/exe";
817
818 #if SANITIZER_NETBSD
819 static const int name[] = {
820 CTL_KERN,
821 KERN_PROC_ARGS,
822 -1,
823 KERN_PROC_PATHNAME,
824 };
825 char path[400];
826 uptr len;
827
828 len = sizeof(path);
829 if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1)
830 pathname = path;
831 #elif SANITIZER_SOLARIS
832 pathname = getexecname();
833 CHECK_NE(pathname, NULL);
834 #elif SANITIZER_USE_GETAUXVAL
835 // Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that
836 // rely on that will fail to load shared libraries. Query AT_EXECFN instead.
837 pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN));
838 #endif
839
840 uptr rv = internal_execve(pathname, GetArgv(), GetEnviron());
841 int rverrno;
842 CHECK_EQ(internal_iserror(rv, &rverrno), true);
843 Printf("execve failed, errno %d\n", rverrno);
844 Die();
845 }
846 #endif // !SANITIZER_OPENBSD
847
848 } // namespace __sanitizer
849
850 #endif
851