1 //===-- sanitizer_linux_libcdep.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_allocator_internal.h"
20 #include "sanitizer_atomic.h"
21 #include "sanitizer_common.h"
22 #include "sanitizer_file.h"
23 #include "sanitizer_flags.h"
24 #include "sanitizer_freebsd.h"
25 #include "sanitizer_getauxval.h"
26 #include "sanitizer_glibc_version.h"
27 #include "sanitizer_linux.h"
28 #include "sanitizer_placement_new.h"
29 #include "sanitizer_procmaps.h"
30
31 #if SANITIZER_NETBSD
32 #define _RTLD_SOURCE // for __lwp_gettcb_fast() / __lwp_getprivate_fast()
33 #endif
34
35 #include <dlfcn.h> // for dlsym()
36 #include <link.h>
37 #include <pthread.h>
38 #include <signal.h>
39 #include <sys/resource.h>
40 #include <syslog.h>
41
42 #if !defined(ElfW)
43 #define ElfW(type) Elf_##type
44 #endif
45
46 #if SANITIZER_FREEBSD
47 #include <pthread_np.h>
48 #include <osreldate.h>
49 #include <sys/sysctl.h>
50 #define pthread_getattr_np pthread_attr_get_np
51 #endif
52
53 #if SANITIZER_NETBSD
54 #include <sys/sysctl.h>
55 #include <sys/tls.h>
56 #include <lwp.h>
57 #endif
58
59 #if SANITIZER_SOLARIS
60 #include <stdlib.h>
61 #include <thread.h>
62 #endif
63
64 #if SANITIZER_ANDROID
65 #include <android/api-level.h>
66 #if !defined(CPU_COUNT) && !defined(__aarch64__)
67 #include <dirent.h>
68 #include <fcntl.h>
69 struct __sanitizer::linux_dirent {
70 long d_ino;
71 off_t d_off;
72 unsigned short d_reclen;
73 char d_name[];
74 };
75 #endif
76 #endif
77
78 #if !SANITIZER_ANDROID
79 #include <elf.h>
80 #include <unistd.h>
81 #endif
82
83 namespace __sanitizer {
84
85 SANITIZER_WEAK_ATTRIBUTE int
86 real_sigaction(int signum, const void *act, void *oldact);
87
internal_sigaction(int signum,const void * act,void * oldact)88 int internal_sigaction(int signum, const void *act, void *oldact) {
89 #if !SANITIZER_GO
90 if (&real_sigaction)
91 return real_sigaction(signum, act, oldact);
92 #endif
93 return sigaction(signum, (const struct sigaction *)act,
94 (struct sigaction *)oldact);
95 }
96
GetThreadStackTopAndBottom(bool at_initialization,uptr * stack_top,uptr * stack_bottom)97 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
98 uptr *stack_bottom) {
99 CHECK(stack_top);
100 CHECK(stack_bottom);
101 if (at_initialization) {
102 // This is the main thread. Libpthread may not be initialized yet.
103 struct rlimit rl;
104 CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
105
106 // Find the mapping that contains a stack variable.
107 MemoryMappingLayout proc_maps(/*cache_enabled*/true);
108 if (proc_maps.Error()) {
109 *stack_top = *stack_bottom = 0;
110 return;
111 }
112 MemoryMappedSegment segment;
113 uptr prev_end = 0;
114 while (proc_maps.Next(&segment)) {
115 if ((uptr)&rl < segment.end) break;
116 prev_end = segment.end;
117 }
118 CHECK((uptr)&rl >= segment.start && (uptr)&rl < segment.end);
119
120 // Get stacksize from rlimit, but clip it so that it does not overlap
121 // with other mappings.
122 uptr stacksize = rl.rlim_cur;
123 if (stacksize > segment.end - prev_end) stacksize = segment.end - prev_end;
124 // When running with unlimited stack size, we still want to set some limit.
125 // The unlimited stack size is caused by 'ulimit -s unlimited'.
126 // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
127 if (stacksize > kMaxThreadStackSize)
128 stacksize = kMaxThreadStackSize;
129 *stack_top = segment.end;
130 *stack_bottom = segment.end - stacksize;
131 return;
132 }
133 uptr stacksize = 0;
134 void *stackaddr = nullptr;
135 #if SANITIZER_SOLARIS
136 stack_t ss;
137 CHECK_EQ(thr_stksegment(&ss), 0);
138 stacksize = ss.ss_size;
139 stackaddr = (char *)ss.ss_sp - stacksize;
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_SOLARIS
188 static uptr g_tls_size;
189
190 #ifdef __i386__
191 #define CHECK_GET_TLS_STATIC_INFO_VERSION (!__GLIBC_PREREQ(2, 27))
192 #else
193 #define CHECK_GET_TLS_STATIC_INFO_VERSION 0
194 #endif
195
196 #if CHECK_GET_TLS_STATIC_INFO_VERSION
197 #define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
198 #else
199 #define DL_INTERNAL_FUNCTION
200 #endif
201
202 namespace {
203 struct GetTlsStaticInfoCall {
204 typedef void (*get_tls_func)(size_t*, size_t*);
205 };
206 struct GetTlsStaticInfoRegparmCall {
207 typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
208 };
209
210 template <typename T>
CallGetTls(void * ptr,size_t * size,size_t * align)211 void CallGetTls(void* ptr, size_t* size, size_t* align) {
212 typename T::get_tls_func get_tls;
213 CHECK_EQ(sizeof(get_tls), sizeof(ptr));
214 internal_memcpy(&get_tls, &ptr, sizeof(ptr));
215 CHECK_NE(get_tls, 0);
216 get_tls(size, align);
217 }
218
CmpLibcVersion(int major,int minor,int patch)219 bool CmpLibcVersion(int major, int minor, int patch) {
220 int ma;
221 int mi;
222 int pa;
223 if (!GetLibcVersion(&ma, &mi, &pa))
224 return false;
225 if (ma > major)
226 return true;
227 if (ma < major)
228 return false;
229 if (mi > minor)
230 return true;
231 if (mi < minor)
232 return false;
233 return pa >= patch;
234 }
235
236 } // namespace
237
InitTlsSize()238 void InitTlsSize() {
239 // all current supported platforms have 16 bytes stack alignment
240 const size_t kStackAlign = 16;
241 void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
242 size_t tls_size = 0;
243 size_t tls_align = 0;
244 // On i?86, _dl_get_tls_static_info used to be internal_function, i.e.
245 // __attribute__((regparm(3), stdcall)) before glibc 2.27 and is normal
246 // function in 2.27 and later.
247 if (CHECK_GET_TLS_STATIC_INFO_VERSION && !CmpLibcVersion(2, 27, 0))
248 CallGetTls<GetTlsStaticInfoRegparmCall>(get_tls_static_info_ptr,
249 &tls_size, &tls_align);
250 else
251 CallGetTls<GetTlsStaticInfoCall>(get_tls_static_info_ptr,
252 &tls_size, &tls_align);
253 if (tls_align < kStackAlign)
254 tls_align = kStackAlign;
255 g_tls_size = RoundUpTo(tls_size, tls_align);
256 }
257 #else
InitTlsSize()258 void InitTlsSize() { }
259 #endif
260
261 #if (defined(__x86_64__) || defined(__i386__) || defined(__mips__) || \
262 defined(__aarch64__) || defined(__powerpc64__) || defined(__s390__) || \
263 defined(__arm__) || SANITIZER_RISCV64) && \
264 SANITIZER_LINUX && !SANITIZER_ANDROID
265 // sizeof(struct pthread) from glibc.
266 static atomic_uintptr_t thread_descriptor_size;
267
ThreadDescriptorSize()268 uptr ThreadDescriptorSize() {
269 uptr val = atomic_load_relaxed(&thread_descriptor_size);
270 if (val)
271 return val;
272 #if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
273 int major;
274 int minor;
275 int patch;
276 if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
277 /* sizeof(struct pthread) values from various glibc versions. */
278 if (SANITIZER_X32)
279 val = 1728; // Assume only one particular version for x32.
280 // For ARM sizeof(struct pthread) changed in Glibc 2.23.
281 else if (SANITIZER_ARM)
282 val = minor <= 22 ? 1120 : 1216;
283 else if (minor <= 3)
284 val = FIRST_32_SECOND_64(1104, 1696);
285 else if (minor == 4)
286 val = FIRST_32_SECOND_64(1120, 1728);
287 else if (minor == 5)
288 val = FIRST_32_SECOND_64(1136, 1728);
289 else if (minor <= 9)
290 val = FIRST_32_SECOND_64(1136, 1712);
291 else if (minor == 10)
292 val = FIRST_32_SECOND_64(1168, 1776);
293 else if (minor == 11 || (minor == 12 && patch == 1))
294 val = FIRST_32_SECOND_64(1168, 2288);
295 else if (minor <= 14)
296 val = FIRST_32_SECOND_64(1168, 2304);
297 else
298 val = FIRST_32_SECOND_64(1216, 2304);
299 }
300 #elif defined(__mips__)
301 // TODO(sagarthakur): add more values as per different glibc versions.
302 val = FIRST_32_SECOND_64(1152, 1776);
303 #elif SANITIZER_RISCV64
304 int major;
305 int minor;
306 int patch;
307 if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
308 // TODO: consider adding an optional runtime check for an unknown (untested)
309 // glibc version
310 if (minor <= 28) // WARNING: the highest tested version is 2.29
311 val = 1772; // no guarantees for this one
312 else if (minor <= 31)
313 val = 1772; // tested against glibc 2.29, 2.31
314 else
315 val = 1936; // tested against glibc 2.32
316 }
317
318 #elif defined(__aarch64__)
319 // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
320 val = 1776;
321 #elif defined(__powerpc64__)
322 val = 1776; // from glibc.ppc64le 2.20-8.fc21
323 #elif defined(__s390__)
324 val = FIRST_32_SECOND_64(1152, 1776); // valid for glibc 2.22
325 #endif
326 if (val)
327 atomic_store_relaxed(&thread_descriptor_size, val);
328 return val;
329 }
330
331 // The offset at which pointer to self is located in the thread descriptor.
332 const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
333
ThreadSelfOffset()334 uptr ThreadSelfOffset() {
335 return kThreadSelfOffset;
336 }
337
338 #if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64
339 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb
340 // head structure. It lies before the static tls blocks.
TlsPreTcbSize()341 static uptr TlsPreTcbSize() {
342 #if defined(__mips__)
343 const uptr kTcbHead = 16; // sizeof (tcbhead_t)
344 #elif defined(__powerpc64__)
345 const uptr kTcbHead = 88; // sizeof (tcbhead_t)
346 #elif SANITIZER_RISCV64
347 const uptr kTcbHead = 16; // sizeof (tcbhead_t)
348 #endif
349 const uptr kTlsAlign = 16;
350 const uptr kTlsPreTcbSize =
351 RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign);
352 return kTlsPreTcbSize;
353 }
354 #endif
355
ThreadSelf()356 uptr ThreadSelf() {
357 uptr descr_addr;
358 #if defined(__i386__)
359 asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
360 #elif defined(__x86_64__)
361 asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
362 #elif defined(__mips__)
363 // MIPS uses TLS variant I. The thread pointer (in hardware register $29)
364 // points to the end of the TCB + 0x7000. The pthread_descr structure is
365 // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
366 // TCB and the size of pthread_descr.
367 const uptr kTlsTcbOffset = 0x7000;
368 uptr thread_pointer;
369 asm volatile(".set push;\
370 .set mips64r2;\
371 rdhwr %0,$29;\
372 .set pop" : "=r" (thread_pointer));
373 descr_addr = thread_pointer - kTlsTcbOffset - TlsPreTcbSize();
374 #elif defined(__aarch64__) || defined(__arm__)
375 descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
376 ThreadDescriptorSize();
377 #elif SANITIZER_RISCV64
378 // https://github.com/riscv/riscv-elf-psabi-doc/issues/53
379 uptr thread_pointer = reinterpret_cast<uptr>(__builtin_thread_pointer());
380 descr_addr = thread_pointer - TlsPreTcbSize();
381 #elif defined(__s390__)
382 descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer());
383 #elif defined(__powerpc64__)
384 // PPC64LE uses TLS variant I. The thread pointer (in GPR 13)
385 // points to the end of the TCB + 0x7000. The pthread_descr structure is
386 // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
387 // TCB and the size of pthread_descr.
388 const uptr kTlsTcbOffset = 0x7000;
389 uptr thread_pointer;
390 asm("addi %0,13,%1" : "=r"(thread_pointer) : "I"(-kTlsTcbOffset));
391 descr_addr = thread_pointer - TlsPreTcbSize();
392 #else
393 #error "unsupported CPU arch"
394 #endif
395 return descr_addr;
396 }
397 #endif // (x86_64 || i386 || MIPS) && SANITIZER_LINUX
398
399 #if SANITIZER_FREEBSD
ThreadSelfSegbase()400 static void **ThreadSelfSegbase() {
401 void **segbase = 0;
402 #if defined(__i386__)
403 // sysarch(I386_GET_GSBASE, segbase);
404 __asm __volatile("mov %%gs:0, %0" : "=r" (segbase));
405 #elif defined(__x86_64__)
406 // sysarch(AMD64_GET_FSBASE, segbase);
407 __asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
408 #else
409 #error "unsupported CPU arch"
410 #endif
411 return segbase;
412 }
413
ThreadSelf()414 uptr ThreadSelf() {
415 return (uptr)ThreadSelfSegbase()[2];
416 }
417 #endif // SANITIZER_FREEBSD
418
419 #if SANITIZER_NETBSD
ThreadSelfTlsTcb()420 static struct tls_tcb * ThreadSelfTlsTcb() {
421 struct tls_tcb *tcb = nullptr;
422 #ifdef __HAVE___LWP_GETTCB_FAST
423 tcb = (struct tls_tcb *)__lwp_gettcb_fast();
424 #elif defined(__HAVE___LWP_GETPRIVATE_FAST)
425 tcb = (struct tls_tcb *)__lwp_getprivate_fast();
426 #endif
427 return tcb;
428 }
429
ThreadSelf()430 uptr ThreadSelf() {
431 return (uptr)ThreadSelfTlsTcb()->tcb_pthread;
432 }
433
GetSizeFromHdr(struct dl_phdr_info * info,size_t size,void * data)434 int GetSizeFromHdr(struct dl_phdr_info *info, size_t size, void *data) {
435 const Elf_Phdr *hdr = info->dlpi_phdr;
436 const Elf_Phdr *last_hdr = hdr + info->dlpi_phnum;
437
438 for (; hdr != last_hdr; ++hdr) {
439 if (hdr->p_type == PT_TLS && info->dlpi_tls_modid == 1) {
440 *(uptr*)data = hdr->p_memsz;
441 break;
442 }
443 }
444 return 0;
445 }
446 #endif // SANITIZER_NETBSD
447
448 #if SANITIZER_ANDROID
449 // Bionic provides this API since S.
450 extern "C" SANITIZER_WEAK_ATTRIBUTE void __libc_get_static_tls_bounds(void **,
451 void **);
452 #endif
453
454 #if !SANITIZER_GO
GetTls(uptr * addr,uptr * size)455 static void GetTls(uptr *addr, uptr *size) {
456 #if SANITIZER_ANDROID
457 if (&__libc_get_static_tls_bounds) {
458 void *start_addr;
459 void *end_addr;
460 __libc_get_static_tls_bounds(&start_addr, &end_addr);
461 *addr = reinterpret_cast<uptr>(start_addr);
462 *size =
463 reinterpret_cast<uptr>(end_addr) - reinterpret_cast<uptr>(start_addr);
464 } else {
465 *addr = 0;
466 *size = 0;
467 }
468 #elif SANITIZER_LINUX
469 #if defined(__x86_64__) || defined(__i386__) || defined(__s390__)
470 *addr = ThreadSelf();
471 *size = GetTlsSize();
472 *addr -= *size;
473 *addr += ThreadDescriptorSize();
474 #elif defined(__mips__) || defined(__aarch64__) || defined(__powerpc64__) || \
475 defined(__arm__) || SANITIZER_RISCV64
476 *addr = ThreadSelf();
477 *size = GetTlsSize();
478 #else
479 *addr = 0;
480 *size = 0;
481 #endif
482 #elif SANITIZER_FREEBSD
483 void** segbase = ThreadSelfSegbase();
484 *addr = 0;
485 *size = 0;
486 if (segbase != 0) {
487 // tcbalign = 16
488 // tls_size = round(tls_static_space, tcbalign);
489 // dtv = segbase[1];
490 // dtv[2] = segbase - tls_static_space;
491 void **dtv = (void**) segbase[1];
492 *addr = (uptr) dtv[2];
493 *size = (*addr == 0) ? 0 : ((uptr) segbase[0] - (uptr) dtv[2]);
494 }
495 #elif SANITIZER_NETBSD
496 struct tls_tcb * const tcb = ThreadSelfTlsTcb();
497 *addr = 0;
498 *size = 0;
499 if (tcb != 0) {
500 // Find size (p_memsz) of dlpi_tls_modid 1 (TLS block of the main program).
501 // ld.elf_so hardcodes the index 1.
502 dl_iterate_phdr(GetSizeFromHdr, size);
503
504 if (*size != 0) {
505 // The block has been found and tcb_dtv[1] contains the base address
506 *addr = (uptr)tcb->tcb_dtv[1];
507 }
508 }
509 #elif SANITIZER_SOLARIS
510 // FIXME
511 *addr = 0;
512 *size = 0;
513 #else
514 #error "Unknown OS"
515 #endif
516 }
517 #endif
518
519 #if !SANITIZER_GO
GetTlsSize()520 uptr GetTlsSize() {
521 #if SANITIZER_FREEBSD || SANITIZER_ANDROID || SANITIZER_NETBSD || \
522 SANITIZER_SOLARIS
523 uptr addr, size;
524 GetTls(&addr, &size);
525 return size;
526 #elif defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64
527 return RoundUpTo(g_tls_size + TlsPreTcbSize(), 16);
528 #else
529 return g_tls_size;
530 #endif
531 }
532 #endif
533
GetThreadStackAndTls(bool main,uptr * stk_addr,uptr * stk_size,uptr * tls_addr,uptr * tls_size)534 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
535 uptr *tls_addr, uptr *tls_size) {
536 #if SANITIZER_GO
537 // Stub implementation for Go.
538 *stk_addr = *stk_size = *tls_addr = *tls_size = 0;
539 #else
540 GetTls(tls_addr, tls_size);
541
542 uptr stack_top, stack_bottom;
543 GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
544 *stk_addr = stack_bottom;
545 *stk_size = stack_top - stack_bottom;
546
547 if (!main) {
548 // If stack and tls intersect, make them non-intersecting.
549 if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
550 CHECK_GT(*tls_addr + *tls_size, *stk_addr);
551 CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
552 *stk_size -= *tls_size;
553 *tls_addr = *stk_addr + *stk_size;
554 }
555 }
556 #endif
557 }
558
559 #if !SANITIZER_FREEBSD
560 typedef ElfW(Phdr) Elf_Phdr;
561 #elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001 // v9.2
562 #define Elf_Phdr XElf32_Phdr
563 #define dl_phdr_info xdl_phdr_info
564 #define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
565 #endif // !SANITIZER_FREEBSD
566
567 struct DlIteratePhdrData {
568 InternalMmapVectorNoCtor<LoadedModule> *modules;
569 bool first;
570 };
571
dl_iterate_phdr_cb(dl_phdr_info * info,size_t size,void * arg)572 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
573 DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
574 InternalScopedString module_name(kMaxPathLength);
575 if (data->first) {
576 data->first = false;
577 // First module is the binary itself.
578 ReadBinaryNameCached(module_name.data(), module_name.size());
579 } else if (info->dlpi_name) {
580 module_name.append("%s", info->dlpi_name);
581 }
582 if (module_name[0] == '\0')
583 return 0;
584 LoadedModule cur_module;
585 cur_module.set(module_name.data(), info->dlpi_addr);
586 for (int i = 0; i < (int)info->dlpi_phnum; i++) {
587 const Elf_Phdr *phdr = &info->dlpi_phdr[i];
588 if (phdr->p_type == PT_LOAD) {
589 uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
590 uptr cur_end = cur_beg + phdr->p_memsz;
591 bool executable = phdr->p_flags & PF_X;
592 bool writable = phdr->p_flags & PF_W;
593 cur_module.addAddressRange(cur_beg, cur_end, executable,
594 writable);
595 }
596 }
597 data->modules->push_back(cur_module);
598 return 0;
599 }
600
601 #if SANITIZER_ANDROID && __ANDROID_API__ < 21
602 extern "C" __attribute__((weak)) int dl_iterate_phdr(
603 int (*)(struct dl_phdr_info *, size_t, void *), void *);
604 #endif
605
requiresProcmaps()606 static bool requiresProcmaps() {
607 #if SANITIZER_ANDROID && __ANDROID_API__ <= 22
608 // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
609 // The runtime check allows the same library to work with
610 // both K and L (and future) Android releases.
611 return AndroidGetApiLevel() <= ANDROID_LOLLIPOP_MR1;
612 #else
613 return false;
614 #endif
615 }
616
procmapsInit(InternalMmapVectorNoCtor<LoadedModule> * modules)617 static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) {
618 MemoryMappingLayout memory_mapping(/*cache_enabled*/true);
619 memory_mapping.DumpListOfModules(modules);
620 }
621
init()622 void ListOfModules::init() {
623 clearOrInit();
624 if (requiresProcmaps()) {
625 procmapsInit(&modules_);
626 } else {
627 DlIteratePhdrData data = {&modules_, true};
628 dl_iterate_phdr(dl_iterate_phdr_cb, &data);
629 }
630 }
631
632 // When a custom loader is used, dl_iterate_phdr may not contain the full
633 // list of modules. Allow callers to fall back to using procmaps.
fallbackInit()634 void ListOfModules::fallbackInit() {
635 if (!requiresProcmaps()) {
636 clearOrInit();
637 procmapsInit(&modules_);
638 } else {
639 clear();
640 }
641 }
642
643 // getrusage does not give us the current RSS, only the max RSS.
644 // Still, this is better than nothing if /proc/self/statm is not available
645 // for some reason, e.g. due to a sandbox.
GetRSSFromGetrusage()646 static uptr GetRSSFromGetrusage() {
647 struct rusage usage;
648 if (getrusage(RUSAGE_SELF, &usage)) // Failed, probably due to a sandbox.
649 return 0;
650 return usage.ru_maxrss << 10; // ru_maxrss is in Kb.
651 }
652
GetRSS()653 uptr GetRSS() {
654 if (!common_flags()->can_use_proc_maps_statm)
655 return GetRSSFromGetrusage();
656 fd_t fd = OpenFile("/proc/self/statm", RdOnly);
657 if (fd == kInvalidFd)
658 return GetRSSFromGetrusage();
659 char buf[64];
660 uptr len = internal_read(fd, buf, sizeof(buf) - 1);
661 internal_close(fd);
662 if ((sptr)len <= 0)
663 return 0;
664 buf[len] = 0;
665 // The format of the file is:
666 // 1084 89 69 11 0 79 0
667 // We need the second number which is RSS in pages.
668 char *pos = buf;
669 // Skip the first number.
670 while (*pos >= '0' && *pos <= '9')
671 pos++;
672 // Skip whitespaces.
673 while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
674 pos++;
675 // Read the number.
676 uptr rss = 0;
677 while (*pos >= '0' && *pos <= '9')
678 rss = rss * 10 + *pos++ - '0';
679 return rss * GetPageSizeCached();
680 }
681
682 // sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used on most platforms as
683 // they allocate memory.
GetNumberOfCPUs()684 u32 GetNumberOfCPUs() {
685 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
686 u32 ncpu;
687 int req[2];
688 uptr len = sizeof(ncpu);
689 req[0] = CTL_HW;
690 req[1] = HW_NCPU;
691 CHECK_EQ(internal_sysctl(req, 2, &ncpu, &len, NULL, 0), 0);
692 return ncpu;
693 #elif SANITIZER_ANDROID && !defined(CPU_COUNT) && !defined(__aarch64__)
694 // Fall back to /sys/devices/system/cpu on Android when cpu_set_t doesn't
695 // exist in sched.h. That is the case for toolchains generated with older
696 // NDKs.
697 // This code doesn't work on AArch64 because internal_getdents makes use of
698 // the 64bit getdents syscall, but cpu_set_t seems to always exist on AArch64.
699 uptr fd = internal_open("/sys/devices/system/cpu", O_RDONLY | O_DIRECTORY);
700 if (internal_iserror(fd))
701 return 0;
702 InternalMmapVector<u8> buffer(4096);
703 uptr bytes_read = buffer.size();
704 uptr n_cpus = 0;
705 u8 *d_type;
706 struct linux_dirent *entry = (struct linux_dirent *)&buffer[bytes_read];
707 while (true) {
708 if ((u8 *)entry >= &buffer[bytes_read]) {
709 bytes_read = internal_getdents(fd, (struct linux_dirent *)buffer.data(),
710 buffer.size());
711 if (internal_iserror(bytes_read) || !bytes_read)
712 break;
713 entry = (struct linux_dirent *)buffer.data();
714 }
715 d_type = (u8 *)entry + entry->d_reclen - 1;
716 if (d_type >= &buffer[bytes_read] ||
717 (u8 *)&entry->d_name[3] >= &buffer[bytes_read])
718 break;
719 if (entry->d_ino != 0 && *d_type == DT_DIR) {
720 if (entry->d_name[0] == 'c' && entry->d_name[1] == 'p' &&
721 entry->d_name[2] == 'u' &&
722 entry->d_name[3] >= '0' && entry->d_name[3] <= '9')
723 n_cpus++;
724 }
725 entry = (struct linux_dirent *)(((u8 *)entry) + entry->d_reclen);
726 }
727 internal_close(fd);
728 return n_cpus;
729 #elif SANITIZER_SOLARIS
730 return sysconf(_SC_NPROCESSORS_ONLN);
731 #else
732 cpu_set_t CPUs;
733 CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
734 return CPU_COUNT(&CPUs);
735 #endif
736 }
737
738 #if SANITIZER_LINUX
739
740 #if SANITIZER_ANDROID
741 static atomic_uint8_t android_log_initialized;
742
AndroidLogInit()743 void AndroidLogInit() {
744 openlog(GetProcessName(), 0, LOG_USER);
745 atomic_store(&android_log_initialized, 1, memory_order_release);
746 }
747
ShouldLogAfterPrintf()748 static bool ShouldLogAfterPrintf() {
749 return atomic_load(&android_log_initialized, memory_order_acquire);
750 }
751
752 extern "C" SANITIZER_WEAK_ATTRIBUTE
753 int async_safe_write_log(int pri, const char* tag, const char* msg);
754 extern "C" SANITIZER_WEAK_ATTRIBUTE
755 int __android_log_write(int prio, const char* tag, const char* msg);
756
757 // ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
758 #define SANITIZER_ANDROID_LOG_INFO 4
759
760 // async_safe_write_log is a new public version of __libc_write_log that is
761 // used behind syslog. It is preferable to syslog as it will not do any dynamic
762 // memory allocation or formatting.
763 // If the function is not available, syslog is preferred for L+ (it was broken
764 // pre-L) as __android_log_write triggers a racey behavior with the strncpy
765 // interceptor. Fallback to __android_log_write pre-L.
WriteOneLineToSyslog(const char * s)766 void WriteOneLineToSyslog(const char *s) {
767 if (&async_safe_write_log) {
768 async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
769 } else if (AndroidGetApiLevel() > ANDROID_KITKAT) {
770 syslog(LOG_INFO, "%s", s);
771 } else {
772 CHECK(&__android_log_write);
773 __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
774 }
775 }
776
777 extern "C" SANITIZER_WEAK_ATTRIBUTE
778 void android_set_abort_message(const char *);
779
SetAbortMessage(const char * str)780 void SetAbortMessage(const char *str) {
781 if (&android_set_abort_message)
782 android_set_abort_message(str);
783 }
784 #else
AndroidLogInit()785 void AndroidLogInit() {}
786
ShouldLogAfterPrintf()787 static bool ShouldLogAfterPrintf() { return true; }
788
WriteOneLineToSyslog(const char * s)789 void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
790
SetAbortMessage(const char * str)791 void SetAbortMessage(const char *str) {}
792 #endif // SANITIZER_ANDROID
793
LogMessageOnPrintf(const char * str)794 void LogMessageOnPrintf(const char *str) {
795 if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
796 WriteToSyslog(str);
797 }
798
799 #endif // SANITIZER_LINUX
800
801 #if SANITIZER_LINUX && !SANITIZER_GO
802 // glibc crashes when using clock_gettime from a preinit_array function as the
803 // vDSO function pointers haven't been initialized yet. __progname is
804 // initialized after the vDSO function pointers, so if it exists, is not null
805 // and is not empty, we can use clock_gettime.
806 extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname;
CanUseVDSO()807 inline bool CanUseVDSO() {
808 // Bionic is safe, it checks for the vDSO function pointers to be initialized.
809 if (SANITIZER_ANDROID)
810 return true;
811 if (&__progname && __progname && *__progname)
812 return true;
813 return false;
814 }
815
816 // MonotonicNanoTime is a timing function that can leverage the vDSO by calling
817 // clock_gettime. real_clock_gettime only exists if clock_gettime is
818 // intercepted, so define it weakly and use it if available.
819 extern "C" SANITIZER_WEAK_ATTRIBUTE
820 int real_clock_gettime(u32 clk_id, void *tp);
MonotonicNanoTime()821 u64 MonotonicNanoTime() {
822 timespec ts;
823 if (CanUseVDSO()) {
824 if (&real_clock_gettime)
825 real_clock_gettime(CLOCK_MONOTONIC, &ts);
826 else
827 clock_gettime(CLOCK_MONOTONIC, &ts);
828 } else {
829 internal_clock_gettime(CLOCK_MONOTONIC, &ts);
830 }
831 return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
832 }
833 #else
834 // Non-Linux & Go always use the syscall.
MonotonicNanoTime()835 u64 MonotonicNanoTime() {
836 timespec ts;
837 internal_clock_gettime(CLOCK_MONOTONIC, &ts);
838 return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
839 }
840 #endif // SANITIZER_LINUX && !SANITIZER_GO
841
ReExec()842 void ReExec() {
843 const char *pathname = "/proc/self/exe";
844
845 #if SANITIZER_NETBSD
846 static const int name[] = {
847 CTL_KERN,
848 KERN_PROC_ARGS,
849 -1,
850 KERN_PROC_PATHNAME,
851 };
852 char path[400];
853 uptr len;
854
855 len = sizeof(path);
856 if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1)
857 pathname = path;
858 #elif SANITIZER_SOLARIS
859 pathname = getexecname();
860 CHECK_NE(pathname, NULL);
861 #elif SANITIZER_USE_GETAUXVAL
862 // Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that
863 // rely on that will fail to load shared libraries. Query AT_EXECFN instead.
864 pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN));
865 #endif
866
867 uptr rv = internal_execve(pathname, GetArgv(), GetEnviron());
868 int rverrno;
869 CHECK_EQ(internal_iserror(rv, &rverrno), true);
870 Printf("execve failed, errno %d\n", rverrno);
871 Die();
872 }
873
UnmapFromTo(uptr from,uptr to)874 void UnmapFromTo(uptr from, uptr to) {
875 if (to == from)
876 return;
877 CHECK(to >= from);
878 uptr res = internal_munmap(reinterpret_cast<void *>(from), to - from);
879 if (UNLIKELY(internal_iserror(res))) {
880 Report("ERROR: %s failed to unmap 0x%zx (%zd) bytes at address %p\n",
881 SanitizerToolName, to - from, to - from, (void *)from);
882 CHECK("unable to unmap" && 0);
883 }
884 }
885
MapDynamicShadow(uptr shadow_size_bytes,uptr shadow_scale,uptr min_shadow_base_alignment,UNUSED uptr & high_mem_end)886 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
887 uptr min_shadow_base_alignment,
888 UNUSED uptr &high_mem_end) {
889 const uptr granularity = GetMmapGranularity();
890 const uptr alignment =
891 Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
892 const uptr left_padding =
893 Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);
894
895 const uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity);
896 const uptr map_size = shadow_size + left_padding + alignment;
897
898 const uptr map_start = (uptr)MmapNoAccess(map_size);
899 CHECK_NE(map_start, ~(uptr)0);
900
901 const uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
902
903 UnmapFromTo(map_start, shadow_start - left_padding);
904 UnmapFromTo(shadow_start + shadow_size, map_start + map_size);
905
906 return shadow_start;
907 }
908
InitializePlatformCommonFlags(CommonFlags * cf)909 void InitializePlatformCommonFlags(CommonFlags *cf) {
910 #if SANITIZER_ANDROID
911 if (&__libc_get_static_tls_bounds == nullptr)
912 cf->detect_leaks = false;
913 #endif
914 }
915
916 } // namespace __sanitizer
917
918 #endif
919