libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp

   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
  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
  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
 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
 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>
 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
 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
 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
 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
 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
 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.
 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
 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
 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
 414 uptr ThreadSelf() {
 415   return (uptr)ThreadSelfSegbase()[2];
 416 }
 417 #endif  // SANITIZER_FREEBSD
 418
 419 #if SANITIZER_NETBSD
 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
 430 uptr ThreadSelf() {
 431   return (uptr)ThreadSelfTlsTcb()->tcb_pthread;
 432 }
 433
 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
 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
 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
 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
 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
 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
 617 static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) {
 618   MemoryMappingLayout memory_mapping(/*cache_enabled*/true);
 619   memory_mapping.DumpListOfModules(modules);
 620 }
 621
 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.
 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.
 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
 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.
 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 #if defined(CPU_COUNT)
 733   cpu_set_t CPUs;
 734   CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
 735   return CPU_COUNT(&CPUs);
 736 #else
 737   return 1;
 738 #endif
 739 #endif
 740 }
 741
 742 #if SANITIZER_LINUX
 743
 744 #if SANITIZER_ANDROID
 745 static atomic_uint8_t android_log_initialized;
 746
 747 void AndroidLogInit() {
 748   openlog(GetProcessName(), 0, LOG_USER);
 749   atomic_store(&android_log_initialized, 1, memory_order_release);
 750 }
 751
 752 static bool ShouldLogAfterPrintf() {
 753   return atomic_load(&android_log_initialized, memory_order_acquire);
 754 }
 755
 756 extern "C" SANITIZER_WEAK_ATTRIBUTE
 757 int async_safe_write_log(int pri, const char* tag, const char* msg);
 758 extern "C" SANITIZER_WEAK_ATTRIBUTE
 759 int __android_log_write(int prio, const char* tag, const char* msg);
 760
 761 // ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
 762 #define SANITIZER_ANDROID_LOG_INFO 4
 763
 764 // async_safe_write_log is a new public version of __libc_write_log that is
 765 // used behind syslog. It is preferable to syslog as it will not do any dynamic
 766 // memory allocation or formatting.
 767 // If the function is not available, syslog is preferred for L+ (it was broken
 768 // pre-L) as __android_log_write triggers a racey behavior with the strncpy
 769 // interceptor. Fallback to __android_log_write pre-L.
 770 void WriteOneLineToSyslog(const char *s) {
 771   if (&async_safe_write_log) {
 772     async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
 773   } else if (AndroidGetApiLevel() > ANDROID_KITKAT) {
 774     syslog(LOG_INFO, "%s", s);
 775   } else {
 776     CHECK(&__android_log_write);
 777     __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
 778   }
 779 }
 780
 781 extern "C" SANITIZER_WEAK_ATTRIBUTE
 782 void android_set_abort_message(const char *);
 783
 784 void SetAbortMessage(const char *str) {
 785   if (&android_set_abort_message)
 786     android_set_abort_message(str);
 787 }
 788 #else
 789 void AndroidLogInit() {}
 790
 791 static bool ShouldLogAfterPrintf() { return true; }
 792
 793 void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
 794
 795 void SetAbortMessage(const char *str) {}
 796 #endif  // SANITIZER_ANDROID
 797
 798 void LogMessageOnPrintf(const char *str) {
 799   if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
 800     WriteToSyslog(str);
 801 }
 802
 803 #endif  // SANITIZER_LINUX
 804
 805 #if SANITIZER_LINUX && !SANITIZER_GO
 806 // glibc crashes when using clock_gettime from a preinit_array function as the
 807 // vDSO function pointers haven't been initialized yet. __progname is
 808 // initialized after the vDSO function pointers, so if it exists, is not null
 809 // and is not empty, we can use clock_gettime.
 810 extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname;
 811 inline bool CanUseVDSO() {
 812   // Bionic is safe, it checks for the vDSO function pointers to be initialized.
 813   if (SANITIZER_ANDROID)
 814     return true;
 815   if (&__progname && __progname && *__progname)
 816     return true;
 817   return false;
 818 }
 819
 820 // MonotonicNanoTime is a timing function that can leverage the vDSO by calling
 821 // clock_gettime. real_clock_gettime only exists if clock_gettime is
 822 // intercepted, so define it weakly and use it if available.
 823 extern "C" SANITIZER_WEAK_ATTRIBUTE
 824 int real_clock_gettime(u32 clk_id, void *tp);
 825 u64 MonotonicNanoTime() {
 826   timespec ts;
 827   if (CanUseVDSO()) {
 828     if (&real_clock_gettime)
 829       real_clock_gettime(CLOCK_MONOTONIC, &ts);
 830     else
 831       clock_gettime(CLOCK_MONOTONIC, &ts);
 832   } else {
 833     internal_clock_gettime(CLOCK_MONOTONIC, &ts);
 834   }
 835   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
 836 }
 837 #else
 838 // Non-Linux & Go always use the syscall.
 839 u64 MonotonicNanoTime() {
 840   timespec ts;
 841   internal_clock_gettime(CLOCK_MONOTONIC, &ts);
 842   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
 843 }
 844 #endif  // SANITIZER_LINUX && !SANITIZER_GO
 845
 846 void ReExec() {
 847   const char *pathname = "/proc/self/exe";
 848
 849 #if SANITIZER_NETBSD
 850   static const int name[] = {
 851       CTL_KERN,
 852       KERN_PROC_ARGS,
 853       -1,
 854       KERN_PROC_PATHNAME,
 855   };
 856   char path[400];
 857   uptr len;
 858
 859   len = sizeof(path);
 860   if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1)
 861     pathname = path;
 862 #elif SANITIZER_SOLARIS
 863   pathname = getexecname();
 864   CHECK_NE(pathname, NULL);
 865 #elif SANITIZER_USE_GETAUXVAL
 866   // Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that
 867   // rely on that will fail to load shared libraries. Query AT_EXECFN instead.
 868   pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN));
 869 #endif
 870
 871   uptr rv = internal_execve(pathname, GetArgv(), GetEnviron());
 872   int rverrno;
 873   CHECK_EQ(internal_iserror(rv, &rverrno), true);
 874   Printf("execve failed, errno %d\n", rverrno);
 875   Die();
 876 }
 877
 878 void UnmapFromTo(uptr from, uptr to) {
 879   if (to == from)
 880     return;
 881   CHECK(to >= from);
 882   uptr res = internal_munmap(reinterpret_cast<void *>(from), to - from);
 883   if (UNLIKELY(internal_iserror(res))) {
 884     Report("ERROR: %s failed to unmap 0x%zx (%zd) bytes at address %p\n",
 885            SanitizerToolName, to - from, to - from, (void *)from);
 886     CHECK("unable to unmap" && 0);
 887   }
 888 }
 889
 890 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
 891                       uptr min_shadow_base_alignment,
 892                       UNUSED uptr &high_mem_end) {
 893   const uptr granularity = GetMmapGranularity();
 894   const uptr alignment =
 895       Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
 896   const uptr left_padding =
 897       Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);
 898
 899   const uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity);
 900   const uptr map_size = shadow_size + left_padding + alignment;
 901
 902   const uptr map_start = (uptr)MmapNoAccess(map_size);
 903   CHECK_NE(map_start, ~(uptr)0);
 904
 905   const uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
 906
 907   UnmapFromTo(map_start, shadow_start - left_padding);
 908   UnmapFromTo(shadow_start + shadow_size, map_start + map_size);
 909
 910   return shadow_start;
 911 }
 912
 913 void InitializePlatformCommonFlags(CommonFlags *cf) {
 914 #if SANITIZER_ANDROID
 915   if (&__libc_get_static_tls_bounds == nullptr)
 916     cf->detect_leaks = false;
 917 #endif
 918 }
 919
 920 } // namespace __sanitizer
 921
 922 #endif