libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cc

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