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/mman.h> 40 #include <sys/resource.h> 41 #include <syslog.h> 42 43 #if !defined(ElfW) 44 #define ElfW(type) Elf_##type 45 #endif 46 47 #if SANITIZER_FREEBSD 48 #include <pthread_np.h> 49 #include <stdlib.h> 50 #include <osreldate.h> 51 #include <sys/auxv.h> 52 #include <sys/sysctl.h> 53 #define pthread_getattr_np pthread_attr_get_np 54 // The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before 55 // that, it was never implemented. So just define it to zero. 56 #undef MAP_NORESERVE 57 #define MAP_NORESERVE 0 58 #endif 59 60 #if SANITIZER_NETBSD 61 #include <sys/sysctl.h> 62 #include <sys/tls.h> 63 #include <lwp.h> 64 #endif 65 66 #if SANITIZER_SOLARIS 67 #include <stdlib.h> 68 #include <thread.h> 69 #endif 70 71 #if SANITIZER_ANDROID 72 #include <android/api-level.h> 73 #if !defined(CPU_COUNT) && !defined(__aarch64__) 74 #include <dirent.h> 75 #include <fcntl.h> 76 struct __sanitizer::linux_dirent { 77 long d_ino; 78 off_t d_off; 79 unsigned short d_reclen; 80 char d_name[]; 81 }; 82 #endif 83 #endif 84 85 #if !SANITIZER_ANDROID 86 #include <elf.h> 87 #include <unistd.h> 88 #endif 89 90 namespace __sanitizer { 91 92 SANITIZER_WEAK_ATTRIBUTE int 93 real_sigaction(int signum, const void *act, void *oldact); 94 95 int internal_sigaction(int signum, const void *act, void *oldact) { 96 #if !SANITIZER_GO 97 if (&real_sigaction) 98 return real_sigaction(signum, act, oldact); 99 #endif 100 return sigaction(signum, (const struct sigaction *)act, 101 (struct sigaction *)oldact); 102 } 103 104 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top, 105 uptr *stack_bottom) { 106 CHECK(stack_top); 107 CHECK(stack_bottom); 108 if (at_initialization) { 109 // This is the main thread. Libpthread may not be initialized yet. 110 struct rlimit rl; 111 CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0); 112 113 // Find the mapping that contains a stack variable. 114 MemoryMappingLayout proc_maps(/*cache_enabled*/true); 115 if (proc_maps.Error()) { 116 *stack_top = *stack_bottom = 0; 117 return; 118 } 119 MemoryMappedSegment segment; 120 uptr prev_end = 0; 121 while (proc_maps.Next(&segment)) { 122 if ((uptr)&rl < segment.end) break; 123 prev_end = segment.end; 124 } 125 CHECK((uptr)&rl >= segment.start && (uptr)&rl < segment.end); 126 127 // Get stacksize from rlimit, but clip it so that it does not overlap 128 // with other mappings. 129 uptr stacksize = rl.rlim_cur; 130 if (stacksize > segment.end - prev_end) stacksize = segment.end - prev_end; 131 // When running with unlimited stack size, we still want to set some limit. 132 // The unlimited stack size is caused by 'ulimit -s unlimited'. 133 // Also, for some reason, GNU make spawns subprocesses with unlimited stack. 134 if (stacksize > kMaxThreadStackSize) 135 stacksize = kMaxThreadStackSize; 136 *stack_top = segment.end; 137 *stack_bottom = segment.end - stacksize; 138 return; 139 } 140 uptr stacksize = 0; 141 void *stackaddr = nullptr; 142 #if SANITIZER_SOLARIS 143 stack_t ss; 144 CHECK_EQ(thr_stksegment(&ss), 0); 145 stacksize = ss.ss_size; 146 stackaddr = (char *)ss.ss_sp - stacksize; 147 #else // !SANITIZER_SOLARIS 148 pthread_attr_t attr; 149 pthread_attr_init(&attr); 150 CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0); 151 my_pthread_attr_getstack(&attr, &stackaddr, &stacksize); 152 pthread_attr_destroy(&attr); 153 #endif // SANITIZER_SOLARIS 154 155 *stack_top = (uptr)stackaddr + stacksize; 156 *stack_bottom = (uptr)stackaddr; 157 } 158 159 #if !SANITIZER_GO 160 bool SetEnv(const char *name, const char *value) { 161 void *f = dlsym(RTLD_NEXT, "setenv"); 162 if (!f) 163 return false; 164 typedef int(*setenv_ft)(const char *name, const char *value, int overwrite); 165 setenv_ft setenv_f; 166 CHECK_EQ(sizeof(setenv_f), sizeof(f)); 167 internal_memcpy(&setenv_f, &f, sizeof(f)); 168 return setenv_f(name, value, 1) == 0; 169 } 170 #endif 171 172 __attribute__((unused)) static bool GetLibcVersion(int *major, int *minor, 173 int *patch) { 174 #ifdef _CS_GNU_LIBC_VERSION 175 char buf[64]; 176 uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf)); 177 if (len >= sizeof(buf)) 178 return false; 179 buf[len] = 0; 180 static const char kGLibC[] = "glibc "; 181 if (internal_strncmp(buf, kGLibC, sizeof(kGLibC) - 1) != 0) 182 return false; 183 const char *p = buf + sizeof(kGLibC) - 1; 184 *major = internal_simple_strtoll(p, &p, 10); 185 *minor = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0; 186 *patch = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0; 187 return true; 188 #else 189 return false; 190 #endif 191 } 192 193 // True if we can use dlpi_tls_data. glibc before 2.25 may leave NULL (BZ 194 // #19826) so dlpi_tls_data cannot be used. 195 // 196 // musl before 1.2.3 and FreeBSD as of 12.2 incorrectly set dlpi_tls_data to 197 // the TLS initialization image 198 // https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254774 199 __attribute__((unused)) static int g_use_dlpi_tls_data; 200 201 #if SANITIZER_GLIBC && !SANITIZER_GO 202 __attribute__((unused)) static size_t g_tls_size; 203 void InitTlsSize() { 204 int major, minor, patch; 205 g_use_dlpi_tls_data = 206 GetLibcVersion(&major, &minor, &patch) && major == 2 && minor >= 25; 207 208 #if defined(__aarch64__) || defined(__x86_64__) || defined(__powerpc64__) 209 void *get_tls_static_info = dlsym(RTLD_NEXT, "_dl_get_tls_static_info"); 210 size_t tls_align; 211 ((void (*)(size_t *, size_t *))get_tls_static_info)(&g_tls_size, &tls_align); 212 #endif 213 } 214 #else 215 void InitTlsSize() { } 216 #endif // SANITIZER_GLIBC && !SANITIZER_GO 217 218 // On glibc x86_64, ThreadDescriptorSize() needs to be precise due to the usage 219 // of g_tls_size. On other targets, ThreadDescriptorSize() is only used by lsan 220 // to get the pointer to thread-specific data keys in the thread control block. 221 #if (SANITIZER_FREEBSD || SANITIZER_LINUX) && !SANITIZER_ANDROID && !SANITIZER_GO 222 // sizeof(struct pthread) from glibc. 223 static atomic_uintptr_t thread_descriptor_size; 224 225 static uptr ThreadDescriptorSizeFallback() { 226 uptr val = 0; 227 #if defined(__x86_64__) || defined(__i386__) || defined(__arm__) 228 int major; 229 int minor; 230 int patch; 231 if (GetLibcVersion(&major, &minor, &patch) && major == 2) { 232 /* sizeof(struct pthread) values from various glibc versions. */ 233 if (SANITIZER_X32) 234 val = 1728; // Assume only one particular version for x32. 235 // For ARM sizeof(struct pthread) changed in Glibc 2.23. 236 else if (SANITIZER_ARM) 237 val = minor <= 22 ? 1120 : 1216; 238 else if (minor <= 3) 239 val = FIRST_32_SECOND_64(1104, 1696); 240 else if (minor == 4) 241 val = FIRST_32_SECOND_64(1120, 1728); 242 else if (minor == 5) 243 val = FIRST_32_SECOND_64(1136, 1728); 244 else if (minor <= 9) 245 val = FIRST_32_SECOND_64(1136, 1712); 246 else if (minor == 10) 247 val = FIRST_32_SECOND_64(1168, 1776); 248 else if (minor == 11 || (minor == 12 && patch == 1)) 249 val = FIRST_32_SECOND_64(1168, 2288); 250 else if (minor <= 14) 251 val = FIRST_32_SECOND_64(1168, 2304); 252 else if (minor < 32) // Unknown version 253 val = FIRST_32_SECOND_64(1216, 2304); 254 else // minor == 32 255 val = FIRST_32_SECOND_64(1344, 2496); 256 } 257 #elif defined(__s390__) || defined(__sparc__) 258 // The size of a prefix of TCB including pthread::{specific_1stblock,specific} 259 // suffices. Just return offsetof(struct pthread, specific_used), which hasn't 260 // changed since 2007-05. Technically this applies to i386/x86_64 as well but 261 // we call _dl_get_tls_static_info and need the precise size of struct 262 // pthread. 263 return FIRST_32_SECOND_64(524, 1552); 264 #elif defined(__mips__) 265 // TODO(sagarthakur): add more values as per different glibc versions. 266 val = FIRST_32_SECOND_64(1152, 1776); 267 #elif SANITIZER_RISCV64 268 int major; 269 int minor; 270 int patch; 271 if (GetLibcVersion(&major, &minor, &patch) && major == 2) { 272 // TODO: consider adding an optional runtime check for an unknown (untested) 273 // glibc version 274 if (minor <= 28) // WARNING: the highest tested version is 2.29 275 val = 1772; // no guarantees for this one 276 else if (minor <= 31) 277 val = 1772; // tested against glibc 2.29, 2.31 278 else 279 val = 1936; // tested against glibc 2.32 280 } 281 282 #elif defined(__aarch64__) 283 // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22. 284 val = 1776; 285 #elif defined(__powerpc64__) 286 val = 1776; // from glibc.ppc64le 2.20-8.fc21 287 #endif 288 return val; 289 } 290 291 uptr ThreadDescriptorSize() { 292 uptr val = atomic_load_relaxed(&thread_descriptor_size); 293 if (val) 294 return val; 295 // _thread_db_sizeof_pthread is a GLIBC_PRIVATE symbol that is exported in 296 // glibc 2.34 and later. 297 if (unsigned *psizeof = static_cast<unsigned *>( 298 dlsym(RTLD_DEFAULT, "_thread_db_sizeof_pthread"))) 299 val = *psizeof; 300 if (!val) 301 val = ThreadDescriptorSizeFallback(); 302 atomic_store_relaxed(&thread_descriptor_size, val); 303 return val; 304 } 305 306 #if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64 307 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb 308 // head structure. It lies before the static tls blocks. 309 static uptr TlsPreTcbSize() { 310 #if defined(__mips__) 311 const uptr kTcbHead = 16; // sizeof (tcbhead_t) 312 #elif defined(__powerpc64__) 313 const uptr kTcbHead = 88; // sizeof (tcbhead_t) 314 #elif SANITIZER_RISCV64 315 const uptr kTcbHead = 16; // sizeof (tcbhead_t) 316 #endif 317 const uptr kTlsAlign = 16; 318 const uptr kTlsPreTcbSize = 319 RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign); 320 return kTlsPreTcbSize; 321 } 322 #endif 323 324 namespace { 325 struct TlsBlock { 326 uptr begin, end, align; 327 size_t tls_modid; 328 bool operator<(const TlsBlock &rhs) const { return begin < rhs.begin; } 329 }; 330 } // namespace 331 332 #ifdef __s390__ 333 extern "C" uptr __tls_get_offset(void *arg); 334 335 static uptr TlsGetOffset(uptr ti_module, uptr ti_offset) { 336 // The __tls_get_offset ABI requires %r12 to point to GOT and %r2 to be an 337 // offset of a struct tls_index inside GOT. We don't possess either of the 338 // two, so violate the letter of the "ELF Handling For Thread-Local 339 // Storage" document and assume that the implementation just dereferences 340 // %r2 + %r12. 341 uptr tls_index[2] = {ti_module, ti_offset}; 342 register uptr r2 asm("2") = 0; 343 register void *r12 asm("12") = tls_index; 344 asm("basr %%r14, %[__tls_get_offset]" 345 : "+r"(r2) 346 : [__tls_get_offset] "r"(__tls_get_offset), "r"(r12) 347 : "memory", "cc", "0", "1", "3", "4", "5", "14"); 348 return r2; 349 } 350 #else 351 extern "C" void *__tls_get_addr(size_t *); 352 #endif 353 354 static int CollectStaticTlsBlocks(struct dl_phdr_info *info, size_t size, 355 void *data) { 356 if (!info->dlpi_tls_modid) 357 return 0; 358 uptr begin = (uptr)info->dlpi_tls_data; 359 if (!g_use_dlpi_tls_data) { 360 // Call __tls_get_addr as a fallback. This forces TLS allocation on glibc 361 // and FreeBSD. 362 #ifdef __s390__ 363 begin = (uptr)__builtin_thread_pointer() + 364 TlsGetOffset(info->dlpi_tls_modid, 0); 365 #else 366 size_t mod_and_off[2] = {info->dlpi_tls_modid, 0}; 367 begin = (uptr)__tls_get_addr(mod_and_off); 368 #endif 369 } 370 for (unsigned i = 0; i != info->dlpi_phnum; ++i) 371 if (info->dlpi_phdr[i].p_type == PT_TLS) { 372 static_cast<InternalMmapVector<TlsBlock> *>(data)->push_back( 373 TlsBlock{begin, begin + info->dlpi_phdr[i].p_memsz, 374 info->dlpi_phdr[i].p_align, info->dlpi_tls_modid}); 375 break; 376 } 377 return 0; 378 } 379 380 __attribute__((unused)) static void GetStaticTlsBoundary(uptr *addr, uptr *size, 381 uptr *align) { 382 InternalMmapVector<TlsBlock> ranges; 383 dl_iterate_phdr(CollectStaticTlsBlocks, &ranges); 384 uptr len = ranges.size(); 385 Sort(ranges.begin(), len); 386 // Find the range with tls_modid=1. For glibc, because libc.so uses PT_TLS, 387 // this module is guaranteed to exist and is one of the initially loaded 388 // modules. 389 uptr one = 0; 390 while (one != len && ranges[one].tls_modid != 1) ++one; 391 if (one == len) { 392 // This may happen with musl if no module uses PT_TLS. 393 *addr = 0; 394 *size = 0; 395 *align = 1; 396 return; 397 } 398 // Find the maximum consecutive ranges. We consider two modules consecutive if 399 // the gap is smaller than the alignment. The dynamic loader places static TLS 400 // blocks this way not to waste space. 401 uptr l = one; 402 *align = ranges[l].align; 403 while (l != 0 && ranges[l].begin < ranges[l - 1].end + ranges[l - 1].align) 404 *align = Max(*align, ranges[--l].align); 405 uptr r = one + 1; 406 while (r != len && ranges[r].begin < ranges[r - 1].end + ranges[r - 1].align) 407 *align = Max(*align, ranges[r++].align); 408 *addr = ranges[l].begin; 409 *size = ranges[r - 1].end - ranges[l].begin; 410 } 411 #endif // (x86_64 || i386 || mips || ...) && (SANITIZER_FREEBSD || 412 // SANITIZER_LINUX) && !SANITIZER_ANDROID && !SANITIZER_GO 413 414 #if SANITIZER_NETBSD 415 static struct tls_tcb * ThreadSelfTlsTcb() { 416 struct tls_tcb *tcb = nullptr; 417 #ifdef __HAVE___LWP_GETTCB_FAST 418 tcb = (struct tls_tcb *)__lwp_gettcb_fast(); 419 #elif defined(__HAVE___LWP_GETPRIVATE_FAST) 420 tcb = (struct tls_tcb *)__lwp_getprivate_fast(); 421 #endif 422 return tcb; 423 } 424 425 uptr ThreadSelf() { 426 return (uptr)ThreadSelfTlsTcb()->tcb_pthread; 427 } 428 429 int GetSizeFromHdr(struct dl_phdr_info *info, size_t size, void *data) { 430 const Elf_Phdr *hdr = info->dlpi_phdr; 431 const Elf_Phdr *last_hdr = hdr + info->dlpi_phnum; 432 433 for (; hdr != last_hdr; ++hdr) { 434 if (hdr->p_type == PT_TLS && info->dlpi_tls_modid == 1) { 435 *(uptr*)data = hdr->p_memsz; 436 break; 437 } 438 } 439 return 0; 440 } 441 #endif // SANITIZER_NETBSD 442 443 #if SANITIZER_ANDROID 444 // Bionic provides this API since S. 445 extern "C" SANITIZER_WEAK_ATTRIBUTE void __libc_get_static_tls_bounds(void **, 446 void **); 447 #endif 448 449 #if !SANITIZER_GO 450 static void GetTls(uptr *addr, uptr *size) { 451 #if SANITIZER_ANDROID 452 if (&__libc_get_static_tls_bounds) { 453 void *start_addr; 454 void *end_addr; 455 __libc_get_static_tls_bounds(&start_addr, &end_addr); 456 *addr = reinterpret_cast<uptr>(start_addr); 457 *size = 458 reinterpret_cast<uptr>(end_addr) - reinterpret_cast<uptr>(start_addr); 459 } else { 460 *addr = 0; 461 *size = 0; 462 } 463 #elif SANITIZER_GLIBC && defined(__x86_64__) 464 // For aarch64 and x86-64, use an O(1) approach which requires relatively 465 // precise ThreadDescriptorSize. g_tls_size was initialized in InitTlsSize. 466 asm("mov %%fs:16,%0" : "=r"(*addr)); 467 *size = g_tls_size; 468 *addr -= *size; 469 *addr += ThreadDescriptorSize(); 470 #elif SANITIZER_GLIBC && defined(__aarch64__) 471 *addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) - 472 ThreadDescriptorSize(); 473 *size = g_tls_size + ThreadDescriptorSize(); 474 #elif SANITIZER_GLIBC && defined(__powerpc64__) 475 // Workaround for glibc<2.25(?). 2.27 is known to not need this. 476 uptr tp; 477 asm("addi %0,13,-0x7000" : "=r"(tp)); 478 const uptr pre_tcb_size = TlsPreTcbSize(); 479 *addr = tp - pre_tcb_size; 480 *size = g_tls_size + pre_tcb_size; 481 #elif SANITIZER_FREEBSD || SANITIZER_LINUX 482 uptr align; 483 GetStaticTlsBoundary(addr, size, &align); 484 #if defined(__x86_64__) || defined(__i386__) || defined(__s390__) || \ 485 defined(__sparc__) 486 if (SANITIZER_GLIBC) { 487 #if defined(__x86_64__) || defined(__i386__) 488 align = Max<uptr>(align, 64); 489 #else 490 align = Max<uptr>(align, 16); 491 #endif 492 } 493 const uptr tp = RoundUpTo(*addr + *size, align); 494 495 // lsan requires the range to additionally cover the static TLS surplus 496 // (elf/dl-tls.c defines 1664). Otherwise there may be false positives for 497 // allocations only referenced by tls in dynamically loaded modules. 498 if (SANITIZER_GLIBC) 499 *size += 1644; 500 else if (SANITIZER_FREEBSD) 501 *size += 128; // RTLD_STATIC_TLS_EXTRA 502 503 // Extend the range to include the thread control block. On glibc, lsan needs 504 // the range to include pthread::{specific_1stblock,specific} so that 505 // allocations only referenced by pthread_setspecific can be scanned. This may 506 // underestimate by at most TLS_TCB_ALIGN-1 bytes but it should be fine 507 // because the number of bytes after pthread::specific is larger. 508 *addr = tp - RoundUpTo(*size, align); 509 *size = tp - *addr + ThreadDescriptorSize(); 510 #else 511 if (SANITIZER_GLIBC) 512 *size += 1664; 513 else if (SANITIZER_FREEBSD) 514 *size += 128; // RTLD_STATIC_TLS_EXTRA 515 #if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64 516 const uptr pre_tcb_size = TlsPreTcbSize(); 517 *addr -= pre_tcb_size; 518 *size += pre_tcb_size; 519 #else 520 // arm and aarch64 reserve two words at TP, so this underestimates the range. 521 // However, this is sufficient for the purpose of finding the pointers to 522 // thread-specific data keys. 523 const uptr tcb_size = ThreadDescriptorSize(); 524 *addr -= tcb_size; 525 *size += tcb_size; 526 #endif 527 #endif 528 #elif SANITIZER_NETBSD 529 struct tls_tcb * const tcb = ThreadSelfTlsTcb(); 530 *addr = 0; 531 *size = 0; 532 if (tcb != 0) { 533 // Find size (p_memsz) of dlpi_tls_modid 1 (TLS block of the main program). 534 // ld.elf_so hardcodes the index 1. 535 dl_iterate_phdr(GetSizeFromHdr, size); 536 537 if (*size != 0) { 538 // The block has been found and tcb_dtv[1] contains the base address 539 *addr = (uptr)tcb->tcb_dtv[1]; 540 } 541 } 542 #elif SANITIZER_SOLARIS 543 // FIXME 544 *addr = 0; 545 *size = 0; 546 #else 547 #error "Unknown OS" 548 #endif 549 } 550 #endif 551 552 #if !SANITIZER_GO 553 uptr GetTlsSize() { 554 #if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \ 555 SANITIZER_SOLARIS 556 uptr addr, size; 557 GetTls(&addr, &size); 558 return size; 559 #else 560 return 0; 561 #endif 562 } 563 #endif 564 565 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size, 566 uptr *tls_addr, uptr *tls_size) { 567 #if SANITIZER_GO 568 // Stub implementation for Go. 569 *stk_addr = *stk_size = *tls_addr = *tls_size = 0; 570 #else 571 GetTls(tls_addr, tls_size); 572 573 uptr stack_top, stack_bottom; 574 GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom); 575 *stk_addr = stack_bottom; 576 *stk_size = stack_top - stack_bottom; 577 578 if (!main) { 579 // If stack and tls intersect, make them non-intersecting. 580 if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) { 581 if (*stk_addr + *stk_size < *tls_addr + *tls_size) 582 *tls_size = *stk_addr + *stk_size - *tls_addr; 583 *stk_size = *tls_addr - *stk_addr; 584 } 585 } 586 #endif 587 } 588 589 #if !SANITIZER_FREEBSD 590 typedef ElfW(Phdr) Elf_Phdr; 591 #elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001 // v9.2 592 #define Elf_Phdr XElf32_Phdr 593 #define dl_phdr_info xdl_phdr_info 594 #define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b)) 595 #endif // !SANITIZER_FREEBSD 596 597 struct DlIteratePhdrData { 598 InternalMmapVectorNoCtor<LoadedModule> *modules; 599 bool first; 600 }; 601 602 static int AddModuleSegments(const char *module_name, dl_phdr_info *info, 603 InternalMmapVectorNoCtor<LoadedModule> *modules) { 604 if (module_name[0] == '\0') 605 return 0; 606 LoadedModule cur_module; 607 cur_module.set(module_name, info->dlpi_addr); 608 for (int i = 0; i < (int)info->dlpi_phnum; i++) { 609 const Elf_Phdr *phdr = &info->dlpi_phdr[i]; 610 if (phdr->p_type == PT_LOAD) { 611 uptr cur_beg = info->dlpi_addr + phdr->p_vaddr; 612 uptr cur_end = cur_beg + phdr->p_memsz; 613 bool executable = phdr->p_flags & PF_X; 614 bool writable = phdr->p_flags & PF_W; 615 cur_module.addAddressRange(cur_beg, cur_end, executable, 616 writable); 617 } else if (phdr->p_type == PT_NOTE) { 618 # ifdef NT_GNU_BUILD_ID 619 uptr off = 0; 620 while (off + sizeof(ElfW(Nhdr)) < phdr->p_memsz) { 621 auto *nhdr = reinterpret_cast<const ElfW(Nhdr) *>(info->dlpi_addr + 622 phdr->p_vaddr + off); 623 constexpr auto kGnuNamesz = 4; // "GNU" with NUL-byte. 624 static_assert(kGnuNamesz % 4 == 0, "kGnuNameSize is aligned to 4."); 625 if (nhdr->n_type == NT_GNU_BUILD_ID && nhdr->n_namesz == kGnuNamesz) { 626 if (off + sizeof(ElfW(Nhdr)) + nhdr->n_namesz + nhdr->n_descsz > 627 phdr->p_memsz) { 628 // Something is very wrong, bail out instead of reading potentially 629 // arbitrary memory. 630 break; 631 } 632 const char *name = 633 reinterpret_cast<const char *>(nhdr) + sizeof(*nhdr); 634 if (internal_memcmp(name, "GNU", 3) == 0) { 635 const char *value = reinterpret_cast<const char *>(nhdr) + 636 sizeof(*nhdr) + kGnuNamesz; 637 cur_module.setUuid(value, nhdr->n_descsz); 638 break; 639 } 640 } 641 off += sizeof(*nhdr) + RoundUpTo(nhdr->n_namesz, 4) + 642 RoundUpTo(nhdr->n_descsz, 4); 643 } 644 # endif 645 } 646 } 647 modules->push_back(cur_module); 648 return 0; 649 } 650 651 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) { 652 DlIteratePhdrData *data = (DlIteratePhdrData *)arg; 653 if (data->first) { 654 InternalMmapVector<char> module_name(kMaxPathLength); 655 data->first = false; 656 // First module is the binary itself. 657 ReadBinaryNameCached(module_name.data(), module_name.size()); 658 return AddModuleSegments(module_name.data(), info, data->modules); 659 } 660 661 if (info->dlpi_name) { 662 InternalScopedString module_name; 663 module_name.append("%s", info->dlpi_name); 664 return AddModuleSegments(module_name.data(), info, data->modules); 665 } 666 667 return 0; 668 } 669 670 #if SANITIZER_ANDROID && __ANDROID_API__ < 21 671 extern "C" __attribute__((weak)) int dl_iterate_phdr( 672 int (*)(struct dl_phdr_info *, size_t, void *), void *); 673 #endif 674 675 static bool requiresProcmaps() { 676 #if SANITIZER_ANDROID && __ANDROID_API__ <= 22 677 // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken. 678 // The runtime check allows the same library to work with 679 // both K and L (and future) Android releases. 680 return AndroidGetApiLevel() <= ANDROID_LOLLIPOP_MR1; 681 #else 682 return false; 683 #endif 684 } 685 686 static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) { 687 MemoryMappingLayout memory_mapping(/*cache_enabled*/true); 688 memory_mapping.DumpListOfModules(modules); 689 } 690 691 void ListOfModules::init() { 692 clearOrInit(); 693 if (requiresProcmaps()) { 694 procmapsInit(&modules_); 695 } else { 696 DlIteratePhdrData data = {&modules_, true}; 697 dl_iterate_phdr(dl_iterate_phdr_cb, &data); 698 } 699 } 700 701 // When a custom loader is used, dl_iterate_phdr may not contain the full 702 // list of modules. Allow callers to fall back to using procmaps. 703 void ListOfModules::fallbackInit() { 704 if (!requiresProcmaps()) { 705 clearOrInit(); 706 procmapsInit(&modules_); 707 } else { 708 clear(); 709 } 710 } 711 712 // getrusage does not give us the current RSS, only the max RSS. 713 // Still, this is better than nothing if /proc/self/statm is not available 714 // for some reason, e.g. due to a sandbox. 715 static uptr GetRSSFromGetrusage() { 716 struct rusage usage; 717 if (getrusage(RUSAGE_SELF, &usage)) // Failed, probably due to a sandbox. 718 return 0; 719 return usage.ru_maxrss << 10; // ru_maxrss is in Kb. 720 } 721 722 uptr GetRSS() { 723 if (!common_flags()->can_use_proc_maps_statm) 724 return GetRSSFromGetrusage(); 725 fd_t fd = OpenFile("/proc/self/statm", RdOnly); 726 if (fd == kInvalidFd) 727 return GetRSSFromGetrusage(); 728 char buf[64]; 729 uptr len = internal_read(fd, buf, sizeof(buf) - 1); 730 internal_close(fd); 731 if ((sptr)len <= 0) 732 return 0; 733 buf[len] = 0; 734 // The format of the file is: 735 // 1084 89 69 11 0 79 0 736 // We need the second number which is RSS in pages. 737 char *pos = buf; 738 // Skip the first number. 739 while (*pos >= '0' && *pos <= '9') 740 pos++; 741 // Skip whitespaces. 742 while (!(*pos >= '0' && *pos <= '9') && *pos != 0) 743 pos++; 744 // Read the number. 745 uptr rss = 0; 746 while (*pos >= '0' && *pos <= '9') 747 rss = rss * 10 + *pos++ - '0'; 748 return rss * GetPageSizeCached(); 749 } 750 751 // sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used on most platforms as 752 // they allocate memory. 753 u32 GetNumberOfCPUs() { 754 #if SANITIZER_FREEBSD || SANITIZER_NETBSD 755 u32 ncpu; 756 int req[2]; 757 uptr len = sizeof(ncpu); 758 req[0] = CTL_HW; 759 req[1] = HW_NCPU; 760 CHECK_EQ(internal_sysctl(req, 2, &ncpu, &len, NULL, 0), 0); 761 return ncpu; 762 #elif SANITIZER_ANDROID && !defined(CPU_COUNT) && !defined(__aarch64__) 763 // Fall back to /sys/devices/system/cpu on Android when cpu_set_t doesn't 764 // exist in sched.h. That is the case for toolchains generated with older 765 // NDKs. 766 // This code doesn't work on AArch64 because internal_getdents makes use of 767 // the 64bit getdents syscall, but cpu_set_t seems to always exist on AArch64. 768 uptr fd = internal_open("/sys/devices/system/cpu", O_RDONLY | O_DIRECTORY); 769 if (internal_iserror(fd)) 770 return 0; 771 InternalMmapVector<u8> buffer(4096); 772 uptr bytes_read = buffer.size(); 773 uptr n_cpus = 0; 774 u8 *d_type; 775 struct linux_dirent *entry = (struct linux_dirent *)&buffer[bytes_read]; 776 while (true) { 777 if ((u8 *)entry >= &buffer[bytes_read]) { 778 bytes_read = internal_getdents(fd, (struct linux_dirent *)buffer.data(), 779 buffer.size()); 780 if (internal_iserror(bytes_read) || !bytes_read) 781 break; 782 entry = (struct linux_dirent *)buffer.data(); 783 } 784 d_type = (u8 *)entry + entry->d_reclen - 1; 785 if (d_type >= &buffer[bytes_read] || 786 (u8 *)&entry->d_name[3] >= &buffer[bytes_read]) 787 break; 788 if (entry->d_ino != 0 && *d_type == DT_DIR) { 789 if (entry->d_name[0] == 'c' && entry->d_name[1] == 'p' && 790 entry->d_name[2] == 'u' && 791 entry->d_name[3] >= '0' && entry->d_name[3] <= '9') 792 n_cpus++; 793 } 794 entry = (struct linux_dirent *)(((u8 *)entry) + entry->d_reclen); 795 } 796 internal_close(fd); 797 return n_cpus; 798 #elif SANITIZER_SOLARIS 799 return sysconf(_SC_NPROCESSORS_ONLN); 800 #else 801 cpu_set_t CPUs; 802 CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0); 803 return CPU_COUNT(&CPUs); 804 #endif 805 } 806 807 #if SANITIZER_LINUX 808 809 #if SANITIZER_ANDROID 810 static atomic_uint8_t android_log_initialized; 811 812 void AndroidLogInit() { 813 openlog(GetProcessName(), 0, LOG_USER); 814 atomic_store(&android_log_initialized, 1, memory_order_release); 815 } 816 817 static bool ShouldLogAfterPrintf() { 818 return atomic_load(&android_log_initialized, memory_order_acquire); 819 } 820 821 extern "C" SANITIZER_WEAK_ATTRIBUTE 822 int async_safe_write_log(int pri, const char* tag, const char* msg); 823 extern "C" SANITIZER_WEAK_ATTRIBUTE 824 int __android_log_write(int prio, const char* tag, const char* msg); 825 826 // ANDROID_LOG_INFO is 4, but can't be resolved at runtime. 827 #define SANITIZER_ANDROID_LOG_INFO 4 828 829 // async_safe_write_log is a new public version of __libc_write_log that is 830 // used behind syslog. It is preferable to syslog as it will not do any dynamic 831 // memory allocation or formatting. 832 // If the function is not available, syslog is preferred for L+ (it was broken 833 // pre-L) as __android_log_write triggers a racey behavior with the strncpy 834 // interceptor. Fallback to __android_log_write pre-L. 835 void WriteOneLineToSyslog(const char *s) { 836 if (&async_safe_write_log) { 837 async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s); 838 } else if (AndroidGetApiLevel() > ANDROID_KITKAT) { 839 syslog(LOG_INFO, "%s", s); 840 } else { 841 CHECK(&__android_log_write); 842 __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s); 843 } 844 } 845 846 extern "C" SANITIZER_WEAK_ATTRIBUTE 847 void android_set_abort_message(const char *); 848 849 void SetAbortMessage(const char *str) { 850 if (&android_set_abort_message) 851 android_set_abort_message(str); 852 } 853 #else 854 void AndroidLogInit() {} 855 856 static bool ShouldLogAfterPrintf() { return true; } 857 858 void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); } 859 860 void SetAbortMessage(const char *str) {} 861 #endif // SANITIZER_ANDROID 862 863 void LogMessageOnPrintf(const char *str) { 864 if (common_flags()->log_to_syslog && ShouldLogAfterPrintf()) 865 WriteToSyslog(str); 866 } 867 868 #endif // SANITIZER_LINUX 869 870 #if SANITIZER_GLIBC && !SANITIZER_GO 871 // glibc crashes when using clock_gettime from a preinit_array function as the 872 // vDSO function pointers haven't been initialized yet. __progname is 873 // initialized after the vDSO function pointers, so if it exists, is not null 874 // and is not empty, we can use clock_gettime. 875 extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname; 876 inline bool CanUseVDSO() { return &__progname && __progname && *__progname; } 877 878 // MonotonicNanoTime is a timing function that can leverage the vDSO by calling 879 // clock_gettime. real_clock_gettime only exists if clock_gettime is 880 // intercepted, so define it weakly and use it if available. 881 extern "C" SANITIZER_WEAK_ATTRIBUTE 882 int real_clock_gettime(u32 clk_id, void *tp); 883 u64 MonotonicNanoTime() { 884 timespec ts; 885 if (CanUseVDSO()) { 886 if (&real_clock_gettime) 887 real_clock_gettime(CLOCK_MONOTONIC, &ts); 888 else 889 clock_gettime(CLOCK_MONOTONIC, &ts); 890 } else { 891 internal_clock_gettime(CLOCK_MONOTONIC, &ts); 892 } 893 return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec; 894 } 895 #else 896 // Non-glibc & Go always use the regular function. 897 u64 MonotonicNanoTime() { 898 timespec ts; 899 clock_gettime(CLOCK_MONOTONIC, &ts); 900 return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec; 901 } 902 #endif // SANITIZER_GLIBC && !SANITIZER_GO 903 904 void ReExec() { 905 const char *pathname = "/proc/self/exe"; 906 907 #if SANITIZER_FREEBSD 908 char exe_path[PATH_MAX]; 909 if (elf_aux_info(AT_EXECPATH, exe_path, sizeof(exe_path)) == 0) { 910 char link_path[PATH_MAX]; 911 if (realpath(exe_path, link_path)) 912 pathname = link_path; 913 } 914 #elif SANITIZER_NETBSD 915 static const int name[] = { 916 CTL_KERN, 917 KERN_PROC_ARGS, 918 -1, 919 KERN_PROC_PATHNAME, 920 }; 921 char path[400]; 922 uptr len; 923 924 len = sizeof(path); 925 if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1) 926 pathname = path; 927 #elif SANITIZER_SOLARIS 928 pathname = getexecname(); 929 CHECK_NE(pathname, NULL); 930 #elif SANITIZER_USE_GETAUXVAL 931 // Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that 932 // rely on that will fail to load shared libraries. Query AT_EXECFN instead. 933 pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN)); 934 #endif 935 936 uptr rv = internal_execve(pathname, GetArgv(), GetEnviron()); 937 int rverrno; 938 CHECK_EQ(internal_iserror(rv, &rverrno), true); 939 Printf("execve failed, errno %d\n", rverrno); 940 Die(); 941 } 942 943 void UnmapFromTo(uptr from, uptr to) { 944 if (to == from) 945 return; 946 CHECK(to >= from); 947 uptr res = internal_munmap(reinterpret_cast<void *>(from), to - from); 948 if (UNLIKELY(internal_iserror(res))) { 949 Report("ERROR: %s failed to unmap 0x%zx (%zd) bytes at address %p\n", 950 SanitizerToolName, to - from, to - from, (void *)from); 951 CHECK("unable to unmap" && 0); 952 } 953 } 954 955 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale, 956 uptr min_shadow_base_alignment, 957 UNUSED uptr &high_mem_end) { 958 const uptr granularity = GetMmapGranularity(); 959 const uptr alignment = 960 Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment); 961 const uptr left_padding = 962 Max<uptr>(granularity, 1ULL << min_shadow_base_alignment); 963 964 const uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity); 965 const uptr map_size = shadow_size + left_padding + alignment; 966 967 const uptr map_start = (uptr)MmapNoAccess(map_size); 968 CHECK_NE(map_start, ~(uptr)0); 969 970 const uptr shadow_start = RoundUpTo(map_start + left_padding, alignment); 971 972 UnmapFromTo(map_start, shadow_start - left_padding); 973 UnmapFromTo(shadow_start + shadow_size, map_start + map_size); 974 975 return shadow_start; 976 } 977 978 static uptr MmapSharedNoReserve(uptr addr, uptr size) { 979 return internal_mmap( 980 reinterpret_cast<void *>(addr), size, PROT_READ | PROT_WRITE, 981 MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0); 982 } 983 984 static uptr MremapCreateAlias(uptr base_addr, uptr alias_addr, 985 uptr alias_size) { 986 #if SANITIZER_LINUX 987 return internal_mremap(reinterpret_cast<void *>(base_addr), 0, alias_size, 988 MREMAP_MAYMOVE | MREMAP_FIXED, 989 reinterpret_cast<void *>(alias_addr)); 990 #else 991 CHECK(false && "mremap is not supported outside of Linux"); 992 return 0; 993 #endif 994 } 995 996 static void CreateAliases(uptr start_addr, uptr alias_size, uptr num_aliases) { 997 uptr total_size = alias_size * num_aliases; 998 uptr mapped = MmapSharedNoReserve(start_addr, total_size); 999 CHECK_EQ(mapped, start_addr); 1000 1001 for (uptr i = 1; i < num_aliases; ++i) { 1002 uptr alias_addr = start_addr + i * alias_size; 1003 CHECK_EQ(MremapCreateAlias(start_addr, alias_addr, alias_size), alias_addr); 1004 } 1005 } 1006 1007 uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size, 1008 uptr num_aliases, uptr ring_buffer_size) { 1009 CHECK_EQ(alias_size & (alias_size - 1), 0); 1010 CHECK_EQ(num_aliases & (num_aliases - 1), 0); 1011 CHECK_EQ(ring_buffer_size & (ring_buffer_size - 1), 0); 1012 1013 const uptr granularity = GetMmapGranularity(); 1014 shadow_size = RoundUpTo(shadow_size, granularity); 1015 CHECK_EQ(shadow_size & (shadow_size - 1), 0); 1016 1017 const uptr alias_region_size = alias_size * num_aliases; 1018 const uptr alignment = 1019 2 * Max(Max(shadow_size, alias_region_size), ring_buffer_size); 1020 const uptr left_padding = ring_buffer_size; 1021 1022 const uptr right_size = alignment; 1023 const uptr map_size = left_padding + 2 * alignment; 1024 1025 const uptr map_start = reinterpret_cast<uptr>(MmapNoAccess(map_size)); 1026 CHECK_NE(map_start, static_cast<uptr>(-1)); 1027 const uptr right_start = RoundUpTo(map_start + left_padding, alignment); 1028 1029 UnmapFromTo(map_start, right_start - left_padding); 1030 UnmapFromTo(right_start + right_size, map_start + map_size); 1031 1032 CreateAliases(right_start + right_size / 2, alias_size, num_aliases); 1033 1034 return right_start; 1035 } 1036 1037 void InitializePlatformCommonFlags(CommonFlags *cf) { 1038 #if SANITIZER_ANDROID 1039 if (&__libc_get_static_tls_bounds == nullptr) 1040 cf->detect_leaks = false; 1041 #endif 1042 } 1043 1044 } // namespace __sanitizer 1045 1046 #endif 1047