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
18
19 #include "sanitizer_allocator_internal.h"
20 #include "sanitizer_atomic.h"
21 #include "sanitizer_common.h"
22 #include "sanitizer_flags.h"
23 #include "sanitizer_freebsd.h"
24 #include "sanitizer_linux.h"
25 #include "sanitizer_placement_new.h"
26 #include "sanitizer_procmaps.h"
27 #include "sanitizer_stacktrace.h"
28
29 #if SANITIZER_ANDROID || SANITIZER_FREEBSD
30 #include <dlfcn.h> // for dlsym()
31 #endif
32
33 #include <link.h>
34 #include <pthread.h>
35 #include <signal.h>
36 #include <sys/resource.h>
37
38 #if SANITIZER_FREEBSD
39 #include <pthread_np.h>
40 #include <osreldate.h>
41 #define pthread_getattr_np pthread_attr_get_np
42 #endif
43
44 #if SANITIZER_LINUX
45 #include <sys/prctl.h>
46 #endif
47
48 #if SANITIZER_ANDROID
49 #include <android/api-level.h>
50 #endif
51
52 #if SANITIZER_ANDROID && __ANDROID_API__ < 21
53 #include <android/log.h>
54 #else
55 #include <syslog.h>
56 #endif
57
58 #if !SANITIZER_ANDROID
59 #include <elf.h>
60 #include <unistd.h>
61 #endif
62
63 namespace __sanitizer {
64
65 SANITIZER_WEAK_ATTRIBUTE int
66 real_sigaction(int signum, const void *act, void *oldact);
67
internal_sigaction(int signum,const void * act,void * oldact)68 int internal_sigaction(int signum, const void *act, void *oldact) {
69 #if !SANITIZER_GO
70 if (&real_sigaction)
71 return real_sigaction(signum, act, oldact);
72 #endif
73 return sigaction(signum, (const struct sigaction *)act,
74 (struct sigaction *)oldact);
75 }
76
GetThreadStackTopAndBottom(bool at_initialization,uptr * stack_top,uptr * stack_bottom)77 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
78 uptr *stack_bottom) {
79 CHECK(stack_top);
80 CHECK(stack_bottom);
81 if (at_initialization) {
82 // This is the main thread. Libpthread may not be initialized yet.
83 struct rlimit rl;
84 CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
85
86 // Find the mapping that contains a stack variable.
87 MemoryMappingLayout proc_maps(/*cache_enabled*/true);
88 uptr start, end, offset;
89 uptr prev_end = 0;
90 while (proc_maps.Next(&start, &end, &offset, nullptr, 0,
91 /* protection */nullptr)) {
92 if ((uptr)&rl < end)
93 break;
94 prev_end = end;
95 }
96 CHECK((uptr)&rl >= start && (uptr)&rl < end);
97
98 // Get stacksize from rlimit, but clip it so that it does not overlap
99 // with other mappings.
100 uptr stacksize = rl.rlim_cur;
101 if (stacksize > end - prev_end)
102 stacksize = end - prev_end;
103 // When running with unlimited stack size, we still want to set some limit.
104 // The unlimited stack size is caused by 'ulimit -s unlimited'.
105 // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
106 if (stacksize > kMaxThreadStackSize)
107 stacksize = kMaxThreadStackSize;
108 *stack_top = end;
109 *stack_bottom = end - stacksize;
110 return;
111 }
112 pthread_attr_t attr;
113 pthread_attr_init(&attr);
114 CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
115 uptr stacksize = 0;
116 void *stackaddr = nullptr;
117 my_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
118 pthread_attr_destroy(&attr);
119
120 CHECK_LE(stacksize, kMaxThreadStackSize); // Sanity check.
121 *stack_top = (uptr)stackaddr + stacksize;
122 *stack_bottom = (uptr)stackaddr;
123 }
124
125 #if !SANITIZER_GO
SetEnv(const char * name,const char * value)126 bool SetEnv(const char *name, const char *value) {
127 void *f = dlsym(RTLD_NEXT, "setenv");
128 if (!f)
129 return false;
130 typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
131 setenv_ft setenv_f;
132 CHECK_EQ(sizeof(setenv_f), sizeof(f));
133 internal_memcpy(&setenv_f, &f, sizeof(f));
134 return setenv_f(name, value, 1) == 0;
135 }
136 #endif
137
SanitizerSetThreadName(const char * name)138 bool SanitizerSetThreadName(const char *name) {
139 #ifdef PR_SET_NAME
140 return 0 == prctl(PR_SET_NAME, (unsigned long)name, 0, 0, 0); // NOLINT
141 #else
142 return false;
143 #endif
144 }
145
SanitizerGetThreadName(char * name,int max_len)146 bool SanitizerGetThreadName(char *name, int max_len) {
147 #ifdef PR_GET_NAME
148 char buff[17];
149 if (prctl(PR_GET_NAME, (unsigned long)buff, 0, 0, 0)) // NOLINT
150 return false;
151 internal_strncpy(name, buff, max_len);
152 name[max_len] = 0;
153 return true;
154 #else
155 return false;
156 #endif
157 }
158
159 #if !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO
160 static uptr g_tls_size;
161 #endif
162
163 #ifdef __i386__
164 # define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
165 #else
166 # define DL_INTERNAL_FUNCTION
167 #endif
168
169 #if defined(__mips__) || defined(__powerpc64__)
170 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb
171 // head structure. It lies before the static tls blocks.
TlsPreTcbSize()172 static uptr TlsPreTcbSize() {
173 # if defined(__mips__)
174 const uptr kTcbHead = 16; // sizeof (tcbhead_t)
175 # elif defined(__powerpc64__)
176 const uptr kTcbHead = 88; // sizeof (tcbhead_t)
177 # endif
178 const uptr kTlsAlign = 16;
179 const uptr kTlsPreTcbSize =
180 (ThreadDescriptorSize() + kTcbHead + kTlsAlign - 1) & ~(kTlsAlign - 1);
181 InitTlsSize();
182 g_tls_size = (g_tls_size + kTlsPreTcbSize + kTlsAlign -1) & ~(kTlsAlign - 1);
183 return kTlsPreTcbSize;
184 }
185 #endif
186
InitTlsSize()187 void InitTlsSize() {
188 #if !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO
189 // all current supported platforms have 16 bytes stack alignment
190 const size_t kStackAlign = 16;
191 typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
192 get_tls_func get_tls;
193 void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
194 CHECK_EQ(sizeof(get_tls), sizeof(get_tls_static_info_ptr));
195 internal_memcpy(&get_tls, &get_tls_static_info_ptr,
196 sizeof(get_tls_static_info_ptr));
197 CHECK_NE(get_tls, 0);
198 size_t tls_size = 0;
199 size_t tls_align = 0;
200 get_tls(&tls_size, &tls_align);
201 if (tls_align < kStackAlign)
202 tls_align = kStackAlign;
203 g_tls_size = RoundUpTo(tls_size, tls_align);
204 #endif // !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO
205 }
206
207 #if (defined(__x86_64__) || defined(__i386__) || defined(__mips__) \
208 || defined(__aarch64__) || defined(__powerpc64__)) \
209 && SANITIZER_LINUX && !SANITIZER_ANDROID
210 // sizeof(struct pthread) from glibc.
211 static atomic_uintptr_t kThreadDescriptorSize;
212
ThreadDescriptorSize()213 uptr ThreadDescriptorSize() {
214 uptr val = atomic_load(&kThreadDescriptorSize, memory_order_relaxed);
215 if (val)
216 return val;
217 #if defined(__x86_64__) || defined(__i386__)
218 #ifdef _CS_GNU_LIBC_VERSION
219 char buf[64];
220 uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
221 if (len < sizeof(buf) && internal_strncmp(buf, "glibc 2.", 8) == 0) {
222 char *end;
223 int minor = internal_simple_strtoll(buf + 8, &end, 10);
224 if (end != buf + 8 && (*end == '\0' || *end == '.')) {
225 /* sizeof(struct pthread) values from various glibc versions. */
226 if (SANITIZER_X32)
227 val = 1728; // Assume only one particular version for x32.
228 else if (minor <= 3)
229 val = FIRST_32_SECOND_64(1104, 1696);
230 else if (minor == 4)
231 val = FIRST_32_SECOND_64(1120, 1728);
232 else if (minor == 5)
233 val = FIRST_32_SECOND_64(1136, 1728);
234 else if (minor <= 9)
235 val = FIRST_32_SECOND_64(1136, 1712);
236 else if (minor == 10)
237 val = FIRST_32_SECOND_64(1168, 1776);
238 else if (minor <= 12)
239 val = FIRST_32_SECOND_64(1168, 2288);
240 else if (minor == 13)
241 val = FIRST_32_SECOND_64(1168, 2304);
242 else
243 val = FIRST_32_SECOND_64(1216, 2304);
244 }
245 if (val)
246 atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
247 return val;
248 }
249 #endif
250 #elif defined(__mips__)
251 // TODO(sagarthakur): add more values as per different glibc versions.
252 val = FIRST_32_SECOND_64(1152, 1776);
253 if (val)
254 atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
255 return val;
256 #elif defined(__aarch64__)
257 // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
258 val = 1776;
259 atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
260 return val;
261 #elif defined(__powerpc64__)
262 val = 1776; // from glibc.ppc64le 2.20-8.fc21
263 atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
264 return val;
265 #endif
266 return 0;
267 }
268
269 // The offset at which pointer to self is located in the thread descriptor.
270 const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
271
ThreadSelfOffset()272 uptr ThreadSelfOffset() {
273 return kThreadSelfOffset;
274 }
275
ThreadSelf()276 uptr ThreadSelf() {
277 uptr descr_addr;
278 # if defined(__i386__)
279 asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
280 # elif defined(__x86_64__)
281 asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
282 # elif defined(__mips__)
283 // MIPS uses TLS variant I. The thread pointer (in hardware register $29)
284 // points to the end of the TCB + 0x7000. The pthread_descr structure is
285 // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
286 // TCB and the size of pthread_descr.
287 const uptr kTlsTcbOffset = 0x7000;
288 uptr thread_pointer;
289 asm volatile(".set push;\
290 .set mips64r2;\
291 rdhwr %0,$29;\
292 .set pop" : "=r" (thread_pointer));
293 descr_addr = thread_pointer - kTlsTcbOffset - TlsPreTcbSize();
294 # elif defined(__aarch64__)
295 descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer());
296 # elif defined(__powerpc64__)
297 // PPC64LE uses TLS variant I. The thread pointer (in GPR 13)
298 // points to the end of the TCB + 0x7000. The pthread_descr structure is
299 // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
300 // TCB and the size of pthread_descr.
301 const uptr kTlsTcbOffset = 0x7000;
302 uptr thread_pointer;
303 asm("addi %0,13,%1" : "=r"(thread_pointer) : "I"(-kTlsTcbOffset));
304 descr_addr = thread_pointer - TlsPreTcbSize();
305 # else
306 # error "unsupported CPU arch"
307 # endif
308 return descr_addr;
309 }
310 #endif // (x86_64 || i386 || MIPS) && SANITIZER_LINUX
311
312 #if SANITIZER_FREEBSD
ThreadSelfSegbase()313 static void **ThreadSelfSegbase() {
314 void **segbase = 0;
315 # if defined(__i386__)
316 // sysarch(I386_GET_GSBASE, segbase);
317 __asm __volatile("mov %%gs:0, %0" : "=r" (segbase));
318 # elif defined(__x86_64__)
319 // sysarch(AMD64_GET_FSBASE, segbase);
320 __asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
321 # else
322 # error "unsupported CPU arch for FreeBSD platform"
323 # endif
324 return segbase;
325 }
326
ThreadSelf()327 uptr ThreadSelf() {
328 return (uptr)ThreadSelfSegbase()[2];
329 }
330 #endif // SANITIZER_FREEBSD
331
332 #if !SANITIZER_GO
GetTls(uptr * addr,uptr * size)333 static void GetTls(uptr *addr, uptr *size) {
334 #if SANITIZER_LINUX && !SANITIZER_ANDROID
335 # if defined(__x86_64__) || defined(__i386__)
336 *addr = ThreadSelf();
337 *size = GetTlsSize();
338 *addr -= *size;
339 *addr += ThreadDescriptorSize();
340 # elif defined(__mips__) || defined(__aarch64__) || defined(__powerpc64__)
341 *addr = ThreadSelf();
342 *size = GetTlsSize();
343 # else
344 *addr = 0;
345 *size = 0;
346 # endif
347 #elif SANITIZER_FREEBSD
348 void** segbase = ThreadSelfSegbase();
349 *addr = 0;
350 *size = 0;
351 if (segbase != 0) {
352 // tcbalign = 16
353 // tls_size = round(tls_static_space, tcbalign);
354 // dtv = segbase[1];
355 // dtv[2] = segbase - tls_static_space;
356 void **dtv = (void**) segbase[1];
357 *addr = (uptr) dtv[2];
358 *size = (*addr == 0) ? 0 : ((uptr) segbase[0] - (uptr) dtv[2]);
359 }
360 #elif SANITIZER_ANDROID
361 *addr = 0;
362 *size = 0;
363 #else
364 # error "Unknown OS"
365 #endif
366 }
367 #endif
368
369 #if !SANITIZER_GO
GetTlsSize()370 uptr GetTlsSize() {
371 #if SANITIZER_FREEBSD || SANITIZER_ANDROID
372 uptr addr, size;
373 GetTls(&addr, &size);
374 return size;
375 #else
376 return g_tls_size;
377 #endif
378 }
379 #endif
380
GetThreadStackAndTls(bool main,uptr * stk_addr,uptr * stk_size,uptr * tls_addr,uptr * tls_size)381 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
382 uptr *tls_addr, uptr *tls_size) {
383 #if SANITIZER_GO
384 // Stub implementation for Go.
385 *stk_addr = *stk_size = *tls_addr = *tls_size = 0;
386 #else
387 GetTls(tls_addr, tls_size);
388
389 uptr stack_top, stack_bottom;
390 GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
391 *stk_addr = stack_bottom;
392 *stk_size = stack_top - stack_bottom;
393
394 if (!main) {
395 // If stack and tls intersect, make them non-intersecting.
396 if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
397 CHECK_GT(*tls_addr + *tls_size, *stk_addr);
398 CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
399 *stk_size -= *tls_size;
400 *tls_addr = *stk_addr + *stk_size;
401 }
402 }
403 #endif
404 }
405
406 # if !SANITIZER_FREEBSD
407 typedef ElfW(Phdr) Elf_Phdr;
408 # elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001 // v9.2
409 # define Elf_Phdr XElf32_Phdr
410 # define dl_phdr_info xdl_phdr_info
411 # define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
412 # endif
413
414 struct DlIteratePhdrData {
415 LoadedModule *modules;
416 uptr current_n;
417 bool first;
418 uptr max_n;
419 string_predicate_t filter;
420 };
421
dl_iterate_phdr_cb(dl_phdr_info * info,size_t size,void * arg)422 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
423 DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
424 if (data->current_n == data->max_n)
425 return 0;
426 InternalScopedString module_name(kMaxPathLength);
427 if (data->first) {
428 data->first = false;
429 // First module is the binary itself.
430 ReadBinaryNameCached(module_name.data(), module_name.size());
431 } else if (info->dlpi_name) {
432 module_name.append("%s", info->dlpi_name);
433 }
434 if (module_name[0] == '\0')
435 return 0;
436 if (data->filter && !data->filter(module_name.data()))
437 return 0;
438 LoadedModule *cur_module = &data->modules[data->current_n];
439 cur_module->set(module_name.data(), info->dlpi_addr);
440 data->current_n++;
441 for (int i = 0; i < info->dlpi_phnum; i++) {
442 const Elf_Phdr *phdr = &info->dlpi_phdr[i];
443 if (phdr->p_type == PT_LOAD) {
444 uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
445 uptr cur_end = cur_beg + phdr->p_memsz;
446 bool executable = phdr->p_flags & PF_X;
447 cur_module->addAddressRange(cur_beg, cur_end, executable);
448 }
449 }
450 return 0;
451 }
452
453 #if SANITIZER_ANDROID && __ANDROID_API__ < 21
454 extern "C" __attribute__((weak)) int dl_iterate_phdr(
455 int (*)(struct dl_phdr_info *, size_t, void *), void *);
456 #endif
457
GetListOfModules(LoadedModule * modules,uptr max_modules,string_predicate_t filter)458 uptr GetListOfModules(LoadedModule *modules, uptr max_modules,
459 string_predicate_t filter) {
460 #if SANITIZER_ANDROID && __ANDROID_API__ <= 22
461 u32 api_level = AndroidGetApiLevel();
462 // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
463 // The runtime check allows the same library to work with
464 // both K and L (and future) Android releases.
465 if (api_level <= ANDROID_LOLLIPOP_MR1) { // L or earlier
466 MemoryMappingLayout memory_mapping(false);
467 return memory_mapping.DumpListOfModules(modules, max_modules, filter);
468 }
469 #endif
470 CHECK(modules);
471 DlIteratePhdrData data = {modules, 0, true, max_modules, filter};
472 dl_iterate_phdr(dl_iterate_phdr_cb, &data);
473 return data.current_n;
474 }
475
476 // getrusage does not give us the current RSS, only the max RSS.
477 // Still, this is better than nothing if /proc/self/statm is not available
478 // for some reason, e.g. due to a sandbox.
GetRSSFromGetrusage()479 static uptr GetRSSFromGetrusage() {
480 struct rusage usage;
481 if (getrusage(RUSAGE_SELF, &usage)) // Failed, probably due to a sandbox.
482 return 0;
483 return usage.ru_maxrss << 10; // ru_maxrss is in Kb.
484 }
485
GetRSS()486 uptr GetRSS() {
487 if (!common_flags()->can_use_proc_maps_statm)
488 return GetRSSFromGetrusage();
489 fd_t fd = OpenFile("/proc/self/statm", RdOnly);
490 if (fd == kInvalidFd)
491 return GetRSSFromGetrusage();
492 char buf[64];
493 uptr len = internal_read(fd, buf, sizeof(buf) - 1);
494 internal_close(fd);
495 if ((sptr)len <= 0)
496 return 0;
497 buf[len] = 0;
498 // The format of the file is:
499 // 1084 89 69 11 0 79 0
500 // We need the second number which is RSS in pages.
501 char *pos = buf;
502 // Skip the first number.
503 while (*pos >= '0' && *pos <= '9')
504 pos++;
505 // Skip whitespaces.
506 while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
507 pos++;
508 // Read the number.
509 uptr rss = 0;
510 while (*pos >= '0' && *pos <= '9')
511 rss = rss * 10 + *pos++ - '0';
512 return rss * GetPageSizeCached();
513 }
514
515 // 64-bit Android targets don't provide the deprecated __android_log_write.
516 // Starting with the L release, syslog() works and is preferable to
517 // __android_log_write.
518 #if SANITIZER_LINUX
519
520 #if SANITIZER_ANDROID
521 static atomic_uint8_t android_log_initialized;
522
AndroidLogInit()523 void AndroidLogInit() {
524 atomic_store(&android_log_initialized, 1, memory_order_release);
525 }
526
ShouldLogAfterPrintf()527 bool ShouldLogAfterPrintf() {
528 return atomic_load(&android_log_initialized, memory_order_acquire);
529 }
530 #else
AndroidLogInit()531 void AndroidLogInit() {}
532
ShouldLogAfterPrintf()533 bool ShouldLogAfterPrintf() { return true; }
534 #endif // SANITIZER_ANDROID
535
WriteOneLineToSyslog(const char * s)536 void WriteOneLineToSyslog(const char *s) {
537 #if SANITIZER_ANDROID &&__ANDROID_API__ < 21
538 __android_log_write(ANDROID_LOG_INFO, NULL, s);
539 #else
540 syslog(LOG_INFO, "%s", s);
541 #endif
542 }
543
544 #endif // SANITIZER_LINUX
545
546 } // namespace __sanitizer
547
548 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX
549