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_OPENBSD || 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 #include <dlfcn.h>  // for dlsym()
  32 #include <link.h>
  33 #include <pthread.h>
  34 #include <signal.h>
  35 #include <sys/resource.h>
  36 #include <syslog.h>
  37
  38 #if SANITIZER_FREEBSD
  39 #include <pthread_np.h>
  40 #include <osreldate.h>
  41 #include <sys/sysctl.h>
  42 #define pthread_getattr_np pthread_attr_get_np
  43 #endif
  44
  45 #if SANITIZER_OPENBSD
  46 #include <pthread_np.h>
  47 #include <sys/sysctl.h>
  48 #endif
  49
  50 #if SANITIZER_NETBSD
  51 #include <sys/sysctl.h>
  52 #include <sys/tls.h>
  53 #endif
  54
  55 #if SANITIZER_SOLARIS
  56 #include <stdlib.h>
  57 #include <thread.h>
  58 #endif
  59
  60 #if SANITIZER_ANDROID
  61 #include <android/api-level.h>
  62 #if !defined(CPU_COUNT) && !defined(__aarch64__)
  63 #include <dirent.h>
  64 #include <fcntl.h>
  65 struct __sanitizer::linux_dirent {
  66   long           d_ino;
  67   off_t          d_off;
  68   unsigned short d_reclen;
  69   char           d_name[];
  70 };
  71 #endif
  72 #endif
  73
  74 #if !SANITIZER_ANDROID
  75 #include <elf.h>
  76 #include <unistd.h>
  77 #endif
  78
  79 namespace __sanitizer {
  80
  81 SANITIZER_WEAK_ATTRIBUTE int
  82 real_sigaction(int signum, const void *act, void *oldact);
  83
  84 int internal_sigaction(int signum, const void *act, void *oldact) {
  85 #if !SANITIZER_GO
  86   if (&real_sigaction)
  87     return real_sigaction(signum, act, oldact);
  88 #endif
  89   return sigaction(signum, (const struct sigaction *)act,
  90                    (struct sigaction *)oldact);
  91 }
  92
  93 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
  94                                 uptr *stack_bottom) {
  95   CHECK(stack_top);
  96   CHECK(stack_bottom);
  97   if (at_initialization) {
  98     // This is the main thread. Libpthread may not be initialized yet.
  99     struct rlimit rl;
 100     CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
 101
 102     // Find the mapping that contains a stack variable.
 103     MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 104     if (proc_maps.Error()) {
 105       *stack_top = *stack_bottom = 0;
 106       return;
 107     }
 108     MemoryMappedSegment segment;
 109     uptr prev_end = 0;
 110     while (proc_maps.Next(&segment)) {
 111       if ((uptr)&rl < segment.end) break;
 112       prev_end = segment.end;
 113     }
 114     CHECK((uptr)&rl >= segment.start && (uptr)&rl < segment.end);
 115
 116     // Get stacksize from rlimit, but clip it so that it does not overlap
 117     // with other mappings.
 118     uptr stacksize = rl.rlim_cur;
 119     if (stacksize > segment.end - prev_end) stacksize = segment.end - prev_end;
 120     // When running with unlimited stack size, we still want to set some limit.
 121     // The unlimited stack size is caused by 'ulimit -s unlimited'.
 122     // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
 123     if (stacksize > kMaxThreadStackSize)
 124       stacksize = kMaxThreadStackSize;
 125     *stack_top = segment.end;
 126     *stack_bottom = segment.end - stacksize;
 127     return;
 128   }
 129   uptr stacksize = 0;
 130   void *stackaddr = nullptr;
 131 #if SANITIZER_SOLARIS
 132   stack_t ss;
 133   CHECK_EQ(thr_stksegment(&ss), 0);
 134   stacksize = ss.ss_size;
 135   stackaddr = (char *)ss.ss_sp - stacksize;
 136 #elif SANITIZER_OPENBSD
 137   stack_t sattr;
 138   CHECK_EQ(pthread_stackseg_np(pthread_self(), &sattr), 0);
 139   stackaddr = sattr.ss_sp;
 140   stacksize = sattr.ss_size;
 141 #else  // !SANITIZER_SOLARIS
 142   pthread_attr_t attr;
 143   pthread_attr_init(&attr);
 144   CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
 145   my_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
 146   pthread_attr_destroy(&attr);
 147 #endif // SANITIZER_SOLARIS
 148
 149   *stack_top = (uptr)stackaddr + stacksize;
 150   *stack_bottom = (uptr)stackaddr;
 151 }
 152
 153 #if !SANITIZER_GO
 154 bool SetEnv(const char *name, const char *value) {
 155   void *f = dlsym(RTLD_NEXT, "setenv");
 156   if (!f)
 157     return false;
 158   typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
 159   setenv_ft setenv_f;
 160   CHECK_EQ(sizeof(setenv_f), sizeof(f));
 161   internal_memcpy(&setenv_f, &f, sizeof(f));
 162   return setenv_f(name, value, 1) == 0;
 163 }
 164 #endif
 165
 166 __attribute__((unused)) static bool GetLibcVersion(int *major, int *minor,
 167                                                    int *patch) {
 168 #ifdef _CS_GNU_LIBC_VERSION
 169   char buf[64];
 170   uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
 171   if (len >= sizeof(buf))
 172     return false;
 173   buf[len] = 0;
 174   static const char kGLibC[] = "glibc ";
 175   if (internal_strncmp(buf, kGLibC, sizeof(kGLibC) - 1) != 0)
 176     return false;
 177   const char *p = buf + sizeof(kGLibC) - 1;
 178   *major = internal_simple_strtoll(p, &p, 10);
 179   *minor = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
 180   *patch = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
 181   return true;
 182 #else
 183   return false;
 184 #endif
 185 }
 186
 187 #if !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO &&               \
 188     !SANITIZER_NETBSD && !SANITIZER_OPENBSD && !SANITIZER_SOLARIS
 189 static uptr g_tls_size;
 190
 191 #ifdef __i386__
 192 # define CHECK_GET_TLS_STATIC_INFO_VERSION (!__GLIBC_PREREQ(2, 27))
 193 #else
 194 # define CHECK_GET_TLS_STATIC_INFO_VERSION 0
 195 #endif
 196
 197 #if CHECK_GET_TLS_STATIC_INFO_VERSION
 198 # define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
 199 #else
 200 # define DL_INTERNAL_FUNCTION
 201 #endif
 202
 203 namespace {
 204 struct GetTlsStaticInfoCall {
 205   typedef void (*get_tls_func)(size_t*, size_t*);
 206 };
 207 struct GetTlsStaticInfoRegparmCall {
 208   typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
 209 };
 210
 211 template <typename T>
 212 void CallGetTls(void* ptr, size_t* size, size_t* align) {
 213   typename T::get_tls_func get_tls;
 214   CHECK_EQ(sizeof(get_tls), sizeof(ptr));
 215   internal_memcpy(&get_tls, &ptr, sizeof(ptr));
 216   CHECK_NE(get_tls, 0);
 217   get_tls(size, align);
 218 }
 219
 220 bool CmpLibcVersion(int major, int minor, int patch) {
 221   int ma;
 222   int mi;
 223   int pa;
 224   if (!GetLibcVersion(&ma, &mi, &pa))
 225     return false;
 226   if (ma > major)
 227     return true;
 228   if (ma < major)
 229     return false;
 230   if (mi > minor)
 231     return true;
 232   if (mi < minor)
 233     return false;
 234   return pa >= patch;
 235 }
 236
 237 }  // namespace
 238
 239 void InitTlsSize() {
 240   // all current supported platforms have 16 bytes stack alignment
 241   const size_t kStackAlign = 16;
 242   void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
 243   size_t tls_size = 0;
 244   size_t tls_align = 0;
 245   // On i?86, _dl_get_tls_static_info used to be internal_function, i.e.
 246   // __attribute__((regparm(3), stdcall)) before glibc 2.27 and is normal
 247   // function in 2.27 and later.
 248   if (CHECK_GET_TLS_STATIC_INFO_VERSION && !CmpLibcVersion(2, 27, 0))
 249     CallGetTls<GetTlsStaticInfoRegparmCall>(get_tls_static_info_ptr,
 250                                             &tls_size, &tls_align);
 251   else
 252     CallGetTls<GetTlsStaticInfoCall>(get_tls_static_info_ptr,
 253                                      &tls_size, &tls_align);
 254   if (tls_align < kStackAlign)
 255     tls_align = kStackAlign;
 256   g_tls_size = RoundUpTo(tls_size, tls_align);
 257 }
 258 #else
 259 void InitTlsSize() { }
 260 #endif  // !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO &&
 261         // !SANITIZER_NETBSD && !SANITIZER_SOLARIS
 262
 263 #if (defined(__x86_64__) || defined(__i386__) || defined(__mips__) ||          \
 264      defined(__aarch64__) || defined(__powerpc64__) || defined(__s390__) ||    \
 265      defined(__arm__)) &&                                                      \
 266     SANITIZER_LINUX && !SANITIZER_ANDROID
 267 // sizeof(struct pthread) from glibc.
 268 static atomic_uintptr_t thread_descriptor_size;
 269
 270 uptr ThreadDescriptorSize() {
 271   uptr val = atomic_load_relaxed(&thread_descriptor_size);
 272   if (val)
 273     return val;
 274 #if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
 275   int major;
 276   int minor;
 277   int patch;
 278   if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
 279     /* sizeof(struct pthread) values from various glibc versions.  */
 280     if (SANITIZER_X32)
 281       val = 1728; // Assume only one particular version for x32.
 282     // For ARM sizeof(struct pthread) changed in Glibc 2.23.
 283     else if (SANITIZER_ARM)
 284       val = minor <= 22 ? 1120 : 1216;
 285     else if (minor <= 3)
 286       val = FIRST_32_SECOND_64(1104, 1696);
 287     else if (minor == 4)
 288       val = FIRST_32_SECOND_64(1120, 1728);
 289     else if (minor == 5)
 290       val = FIRST_32_SECOND_64(1136, 1728);
 291     else if (minor <= 9)
 292       val = FIRST_32_SECOND_64(1136, 1712);
 293     else if (minor == 10)
 294       val = FIRST_32_SECOND_64(1168, 1776);
 295     else if (minor == 11 || (minor == 12 && patch == 1))
 296       val = FIRST_32_SECOND_64(1168, 2288);
 297     else if (minor <= 14)
 298       val = FIRST_32_SECOND_64(1168, 2304);
 299     else
 300       val = FIRST_32_SECOND_64(1216, 2304);
 301   }
 302 #elif defined(__mips__)
 303   // TODO(sagarthakur): add more values as per different glibc versions.
 304   val = FIRST_32_SECOND_64(1152, 1776);
 305 #elif defined(__aarch64__)
 306   // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
 307   val = 1776;
 308 #elif defined(__powerpc64__)
 309   val = 1776; // from glibc.ppc64le 2.20-8.fc21
 310 #elif defined(__s390__)
 311   val = FIRST_32_SECOND_64(1152, 1776); // valid for glibc 2.22
 312 #endif
 313   if (val)
 314     atomic_store_relaxed(&thread_descriptor_size, val);
 315   return val;
 316 }
 317
 318 // The offset at which pointer to self is located in the thread descriptor.
 319 const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
 320
 321 uptr ThreadSelfOffset() {
 322   return kThreadSelfOffset;
 323 }
 324
 325 #if defined(__mips__) || defined(__powerpc64__)
 326 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb
 327 // head structure. It lies before the static tls blocks.
 328 static uptr TlsPreTcbSize() {
 329 # if defined(__mips__)
 330   const uptr kTcbHead = 16; // sizeof (tcbhead_t)
 331 # elif defined(__powerpc64__)
 332   const uptr kTcbHead = 88; // sizeof (tcbhead_t)
 333 # endif
 334   const uptr kTlsAlign = 16;
 335   const uptr kTlsPreTcbSize =
 336       RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign);
 337   return kTlsPreTcbSize;
 338 }
 339 #endif
 340
 341 uptr ThreadSelf() {
 342   uptr descr_addr;
 343 # if defined(__i386__)
 344   asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
 345 # elif defined(__x86_64__)
 346   asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
 347 # elif defined(__mips__)
 348   // MIPS uses TLS variant I. The thread pointer (in hardware register $29)
 349   // points to the end of the TCB + 0x7000. The pthread_descr structure is
 350   // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
 351   // TCB and the size of pthread_descr.
 352   const uptr kTlsTcbOffset = 0x7000;
 353   uptr thread_pointer;
 354   asm volatile(".set push;\
 355                 .set mips64r2;\
 356                 rdhwr %0,$29;\
 357                 .set pop" : "=r" (thread_pointer));
 358   descr_addr = thread_pointer - kTlsTcbOffset - TlsPreTcbSize();
 359 # elif defined(__aarch64__) || defined(__arm__)
 360   descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
 361                                       ThreadDescriptorSize();
 362 # elif defined(__s390__)
 363   descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer());
 364 # elif defined(__powerpc64__)
 365   // PPC64LE uses TLS variant I. The thread pointer (in GPR 13)
 366   // points to the end of the TCB + 0x7000. The pthread_descr structure is
 367   // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
 368   // TCB and the size of pthread_descr.
 369   const uptr kTlsTcbOffset = 0x7000;
 370   uptr thread_pointer;
 371   asm("addi %0,13,%1" : "=r"(thread_pointer) : "I"(-kTlsTcbOffset));
 372   descr_addr = thread_pointer - TlsPreTcbSize();
 373 # else
 374 #  error "unsupported CPU arch"
 375 # endif
 376   return descr_addr;
 377 }
 378 #endif  // (x86_64 || i386 || MIPS) && SANITIZER_LINUX
 379
 380 #if SANITIZER_FREEBSD
 381 static void **ThreadSelfSegbase() {
 382   void **segbase = 0;
 383 # if defined(__i386__)
 384   // sysarch(I386_GET_GSBASE, segbase);
 385   __asm __volatile("mov %%gs:0, %0" : "=r" (segbase));
 386 # elif defined(__x86_64__)
 387   // sysarch(AMD64_GET_FSBASE, segbase);
 388   __asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
 389 # else
 390 #  error "unsupported CPU arch"
 391 # endif
 392   return segbase;
 393 }
 394
 395 uptr ThreadSelf() {
 396   return (uptr)ThreadSelfSegbase()[2];
 397 }
 398 #endif  // SANITIZER_FREEBSD
 399
 400 #if SANITIZER_NETBSD
 401 static struct tls_tcb * ThreadSelfTlsTcb() {
 402   struct tls_tcb * tcb;
 403 # ifdef __HAVE___LWP_GETTCB_FAST
 404   tcb = (struct tls_tcb *)__lwp_gettcb_fast();
 405 # elif defined(__HAVE___LWP_GETPRIVATE_FAST)
 406   tcb = (struct tls_tcb *)__lwp_getprivate_fast();
 407 # endif
 408   return tcb;
 409 }
 410
 411 uptr ThreadSelf() {
 412   return (uptr)ThreadSelfTlsTcb()->tcb_pthread;
 413 }
 414
 415 int GetSizeFromHdr(struct dl_phdr_info *info, size_t size, void *data) {
 416   const Elf_Phdr *hdr = info->dlpi_phdr;
 417   const Elf_Phdr *last_hdr = hdr + info->dlpi_phnum;
 418
 419   for (; hdr != last_hdr; ++hdr) {
 420     if (hdr->p_type == PT_TLS && info->dlpi_tls_modid == 1) {
 421       *(uptr*)data = hdr->p_memsz;
 422       break;
 423     }
 424   }
 425   return 0;
 426 }
 427 #endif  // SANITIZER_NETBSD
 428
 429 #if !SANITIZER_GO
 430 static void GetTls(uptr *addr, uptr *size) {
 431 #if SANITIZER_LINUX && !SANITIZER_ANDROID
 432 # if defined(__x86_64__) || defined(__i386__) || defined(__s390__)
 433   *addr = ThreadSelf();
 434   *size = GetTlsSize();
 435   *addr -= *size;
 436   *addr += ThreadDescriptorSize();
 437 # elif defined(__mips__) || defined(__aarch64__) || defined(__powerpc64__) \
 438     || defined(__arm__)
 439   *addr = ThreadSelf();
 440   *size = GetTlsSize();
 441 # else
 442   *addr = 0;
 443   *size = 0;
 444 # endif
 445 #elif SANITIZER_FREEBSD
 446   void** segbase = ThreadSelfSegbase();
 447   *addr = 0;
 448   *size = 0;
 449   if (segbase != 0) {
 450     // tcbalign = 16
 451     // tls_size = round(tls_static_space, tcbalign);
 452     // dtv = segbase[1];
 453     // dtv[2] = segbase - tls_static_space;
 454     void **dtv = (void**) segbase[1];
 455     *addr = (uptr) dtv[2];
 456     *size = (*addr == 0) ? 0 : ((uptr) segbase[0] - (uptr) dtv[2]);
 457   }
 458 #elif SANITIZER_NETBSD
 459   struct tls_tcb * const tcb = ThreadSelfTlsTcb();
 460   *addr = 0;
 461   *size = 0;
 462   if (tcb != 0) {
 463     // Find size (p_memsz) of dlpi_tls_modid 1 (TLS block of the main program).
 464     // ld.elf_so hardcodes the index 1.
 465     dl_iterate_phdr(GetSizeFromHdr, size);
 466
 467     if (*size != 0) {
 468       // The block has been found and tcb_dtv[1] contains the base address
 469       *addr = (uptr)tcb->tcb_dtv[1];
 470     }
 471   }
 472 #elif SANITIZER_OPENBSD
 473   *addr = 0;
 474   *size = 0;
 475 #elif SANITIZER_ANDROID
 476   *addr = 0;
 477   *size = 0;
 478 #elif SANITIZER_SOLARIS
 479   // FIXME
 480   *addr = 0;
 481   *size = 0;
 482 #else
 483 # error "Unknown OS"
 484 #endif
 485 }
 486 #endif
 487
 488 #if !SANITIZER_GO
 489 uptr GetTlsSize() {
 490 #if SANITIZER_FREEBSD || SANITIZER_ANDROID || SANITIZER_NETBSD ||              \
 491     SANITIZER_OPENBSD || SANITIZER_SOLARIS
 492   uptr addr, size;
 493   GetTls(&addr, &size);
 494   return size;
 495 #elif defined(__mips__) || defined(__powerpc64__)
 496   return RoundUpTo(g_tls_size + TlsPreTcbSize(), 16);
 497 #else
 498   return g_tls_size;
 499 #endif
 500 }
 501 #endif
 502
 503 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
 504                           uptr *tls_addr, uptr *tls_size) {
 505 #if SANITIZER_GO
 506   // Stub implementation for Go.
 507   *stk_addr = *stk_size = *tls_addr = *tls_size = 0;
 508 #else
 509   GetTls(tls_addr, tls_size);
 510
 511   uptr stack_top, stack_bottom;
 512   GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
 513   *stk_addr = stack_bottom;
 514   *stk_size = stack_top - stack_bottom;
 515
 516   if (!main) {
 517     // If stack and tls intersect, make them non-intersecting.
 518     if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
 519       CHECK_GT(*tls_addr + *tls_size, *stk_addr);
 520       CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
 521       *stk_size -= *tls_size;
 522       *tls_addr = *stk_addr + *stk_size;
 523     }
 524   }
 525 #endif
 526 }
 527
 528 #if !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
 529 typedef ElfW(Phdr) Elf_Phdr;
 530 #elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001 // v9.2
 531 #define Elf_Phdr XElf32_Phdr
 532 #define dl_phdr_info xdl_phdr_info
 533 #define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
 534 #endif // !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
 535
 536 struct DlIteratePhdrData {
 537   InternalMmapVectorNoCtor<LoadedModule> *modules;
 538   bool first;
 539 };
 540
 541 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
 542   DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
 543   InternalScopedString module_name(kMaxPathLength);
 544   if (data->first) {
 545     data->first = false;
 546     // First module is the binary itself.
 547     ReadBinaryNameCached(module_name.data(), module_name.size());
 548   } else if (info->dlpi_name) {
 549     module_name.append("%s", info->dlpi_name);
 550   }
 551   if (module_name[0] == '\0')
 552     return 0;
 553   LoadedModule cur_module;
 554   cur_module.set(module_name.data(), info->dlpi_addr);
 555   for (int i = 0; i < (int)info->dlpi_phnum; i++) {
 556     const Elf_Phdr *phdr = &info->dlpi_phdr[i];
 557     if (phdr->p_type == PT_LOAD) {
 558       uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
 559       uptr cur_end = cur_beg + phdr->p_memsz;
 560       bool executable = phdr->p_flags & PF_X;
 561       bool writable = phdr->p_flags & PF_W;
 562       cur_module.addAddressRange(cur_beg, cur_end, executable,
 563                                  writable);
 564     }
 565   }
 566   data->modules->push_back(cur_module);
 567   return 0;
 568 }
 569
 570 #if SANITIZER_ANDROID && __ANDROID_API__ < 21
 571 extern "C" __attribute__((weak)) int dl_iterate_phdr(
 572     int (*)(struct dl_phdr_info *, size_t, void *), void *);
 573 #endif
 574
 575 static bool requiresProcmaps() {
 576 #if SANITIZER_ANDROID && __ANDROID_API__ <= 22
 577   // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
 578   // The runtime check allows the same library to work with
 579   // both K and L (and future) Android releases.
 580   return AndroidGetApiLevel() <= ANDROID_LOLLIPOP_MR1;
 581 #else
 582   return false;
 583 #endif
 584 }
 585
 586 static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) {
 587   MemoryMappingLayout memory_mapping(/*cache_enabled*/true);
 588   memory_mapping.DumpListOfModules(modules);
 589 }
 590
 591 void ListOfModules::init() {
 592   clearOrInit();
 593   if (requiresProcmaps()) {
 594     procmapsInit(&modules_);
 595   } else {
 596     DlIteratePhdrData data = {&modules_, true};
 597     dl_iterate_phdr(dl_iterate_phdr_cb, &data);
 598   }
 599 }
 600
 601 // When a custom loader is used, dl_iterate_phdr may not contain the full
 602 // list of modules. Allow callers to fall back to using procmaps.
 603 void ListOfModules::fallbackInit() {
 604   if (!requiresProcmaps()) {
 605     clearOrInit();
 606     procmapsInit(&modules_);
 607   } else {
 608     clear();
 609   }
 610 }
 611
 612 // getrusage does not give us the current RSS, only the max RSS.
 613 // Still, this is better than nothing if /proc/self/statm is not available
 614 // for some reason, e.g. due to a sandbox.
 615 static uptr GetRSSFromGetrusage() {
 616   struct rusage usage;
 617   if (getrusage(RUSAGE_SELF, &usage))  // Failed, probably due to a sandbox.
 618     return 0;
 619   return usage.ru_maxrss << 10;  // ru_maxrss is in Kb.
 620 }
 621
 622 uptr GetRSS() {
 623   if (!common_flags()->can_use_proc_maps_statm)
 624     return GetRSSFromGetrusage();
 625   fd_t fd = OpenFile("/proc/self/statm", RdOnly);
 626   if (fd == kInvalidFd)
 627     return GetRSSFromGetrusage();
 628   char buf[64];
 629   uptr len = internal_read(fd, buf, sizeof(buf) - 1);
 630   internal_close(fd);
 631   if ((sptr)len <= 0)
 632     return 0;
 633   buf[len] = 0;
 634   // The format of the file is:
 635   // 1084 89 69 11 0 79 0
 636   // We need the second number which is RSS in pages.
 637   char *pos = buf;
 638   // Skip the first number.
 639   while (*pos >= '0' && *pos <= '9')
 640     pos++;
 641   // Skip whitespaces.
 642   while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
 643     pos++;
 644   // Read the number.
 645   uptr rss = 0;
 646   while (*pos >= '0' && *pos <= '9')
 647     rss = rss * 10 + *pos++ - '0';
 648   return rss * GetPageSizeCached();
 649 }
 650
 651 // sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used on most platforms as
 652 // they allocate memory.
 653 u32 GetNumberOfCPUs() {
 654 #if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD
 655   u32 ncpu;
 656   int req[2];
 657   uptr len = sizeof(ncpu);
 658   req[0] = CTL_HW;
 659   req[1] = HW_NCPU;
 660   CHECK_EQ(internal_sysctl(req, 2, &ncpu, &len, NULL, 0), 0);
 661   return ncpu;
 662 #elif SANITIZER_ANDROID && !defined(CPU_COUNT) && !defined(__aarch64__)
 663   // Fall back to /sys/devices/system/cpu on Android when cpu_set_t doesn't
 664   // exist in sched.h. That is the case for toolchains generated with older
 665   // NDKs.
 666   // This code doesn't work on AArch64 because internal_getdents makes use of
 667   // the 64bit getdents syscall, but cpu_set_t seems to always exist on AArch64.
 668   uptr fd = internal_open("/sys/devices/system/cpu", O_RDONLY | O_DIRECTORY);
 669   if (internal_iserror(fd))
 670     return 0;
 671   InternalMmapVector<u8> buffer(4096);
 672   uptr bytes_read = buffer.size();
 673   uptr n_cpus = 0;
 674   u8 *d_type;
 675   struct linux_dirent *entry = (struct linux_dirent *)&buffer[bytes_read];
 676   while (true) {
 677     if ((u8 *)entry >= &buffer[bytes_read]) {
 678       bytes_read = internal_getdents(fd, (struct linux_dirent *)buffer.data(),
 679                                      buffer.size());
 680       if (internal_iserror(bytes_read) || !bytes_read)
 681         break;
 682       entry = (struct linux_dirent *)buffer.data();
 683     }
 684     d_type = (u8 *)entry + entry->d_reclen - 1;
 685     if (d_type >= &buffer[bytes_read] ||
 686         (u8 *)&entry->d_name[3] >= &buffer[bytes_read])
 687       break;
 688     if (entry->d_ino != 0 && *d_type == DT_DIR) {
 689       if (entry->d_name[0] == 'c' && entry->d_name[1] == 'p' &&
 690           entry->d_name[2] == 'u' &&
 691           entry->d_name[3] >= '0' && entry->d_name[3] <= '9')
 692         n_cpus++;
 693     }
 694     entry = (struct linux_dirent *)(((u8 *)entry) + entry->d_reclen);
 695   }
 696   internal_close(fd);
 697   return n_cpus;
 698 #elif SANITIZER_SOLARIS
 699   return sysconf(_SC_NPROCESSORS_ONLN);
 700 #else
 701 #if defined(CPU_COUNT)
 702   cpu_set_t CPUs;
 703   CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
 704   return CPU_COUNT(&CPUs);
 705 #else
 706   return 1;
 707 #endif
 708 #endif
 709 }
 710
 711 #if SANITIZER_LINUX
 712
 713 # if SANITIZER_ANDROID
 714 static atomic_uint8_t android_log_initialized;
 715
 716 void AndroidLogInit() {
 717   openlog(GetProcessName(), 0, LOG_USER);
 718   atomic_store(&android_log_initialized, 1, memory_order_release);
 719 }
 720
 721 static bool ShouldLogAfterPrintf() {
 722   return atomic_load(&android_log_initialized, memory_order_acquire);
 723 }
 724
 725 extern "C" SANITIZER_WEAK_ATTRIBUTE
 726 int async_safe_write_log(int pri, const char* tag, const char* msg);
 727 extern "C" SANITIZER_WEAK_ATTRIBUTE
 728 int __android_log_write(int prio, const char* tag, const char* msg);
 729
 730 // ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
 731 #define SANITIZER_ANDROID_LOG_INFO 4
 732
 733 // async_safe_write_log is a new public version of __libc_write_log that is
 734 // used behind syslog. It is preferable to syslog as it will not do any dynamic
 735 // memory allocation or formatting.
 736 // If the function is not available, syslog is preferred for L+ (it was broken
 737 // pre-L) as __android_log_write triggers a racey behavior with the strncpy
 738 // interceptor. Fallback to __android_log_write pre-L.
 739 void WriteOneLineToSyslog(const char *s) {
 740   if (&async_safe_write_log) {
 741     async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
 742   } else if (AndroidGetApiLevel() > ANDROID_KITKAT) {
 743     syslog(LOG_INFO, "%s", s);
 744   } else {
 745     CHECK(&__android_log_write);
 746     __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
 747   }
 748 }
 749
 750 extern "C" SANITIZER_WEAK_ATTRIBUTE
 751 void android_set_abort_message(const char *);
 752
 753 void SetAbortMessage(const char *str) {
 754   if (&android_set_abort_message)
 755     android_set_abort_message(str);
 756 }
 757 # else
 758 void AndroidLogInit() {}
 759
 760 static bool ShouldLogAfterPrintf() { return true; }
 761
 762 void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
 763
 764 void SetAbortMessage(const char *str) {}
 765 # endif  // SANITIZER_ANDROID
 766
 767 void LogMessageOnPrintf(const char *str) {
 768   if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
 769     WriteToSyslog(str);
 770 }
 771
 772 #endif  // SANITIZER_LINUX
 773
 774 #if SANITIZER_LINUX && !SANITIZER_GO
 775 // glibc crashes when using clock_gettime from a preinit_array function as the
 776 // vDSO function pointers haven't been initialized yet. __progname is
 777 // initialized after the vDSO function pointers, so if it exists, is not null
 778 // and is not empty, we can use clock_gettime.
 779 extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname;
 780 INLINE bool CanUseVDSO() {
 781   // Bionic is safe, it checks for the vDSO function pointers to be initialized.
 782   if (SANITIZER_ANDROID)
 783     return true;
 784   if (&__progname && __progname && *__progname)
 785     return true;
 786   return false;
 787 }
 788
 789 // MonotonicNanoTime is a timing function that can leverage the vDSO by calling
 790 // clock_gettime. real_clock_gettime only exists if clock_gettime is
 791 // intercepted, so define it weakly and use it if available.
 792 extern "C" SANITIZER_WEAK_ATTRIBUTE
 793 int real_clock_gettime(u32 clk_id, void *tp);
 794 u64 MonotonicNanoTime() {
 795   timespec ts;
 796   if (CanUseVDSO()) {
 797     if (&real_clock_gettime)
 798       real_clock_gettime(CLOCK_MONOTONIC, &ts);
 799     else
 800       clock_gettime(CLOCK_MONOTONIC, &ts);
 801   } else {
 802     internal_clock_gettime(CLOCK_MONOTONIC, &ts);
 803   }
 804   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
 805 }
 806 #else
 807 // Non-Linux & Go always use the syscall.
 808 u64 MonotonicNanoTime() {
 809   timespec ts;
 810   internal_clock_gettime(CLOCK_MONOTONIC, &ts);
 811   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
 812 }
 813 #endif  // SANITIZER_LINUX && !SANITIZER_GO
 814
 815 #if !SANITIZER_OPENBSD
 816 void ReExec() {
 817   const char *pathname = "/proc/self/exe";
 818
 819 #if SANITIZER_NETBSD
 820   static const int name[] = {
 821       CTL_KERN,
 822       KERN_PROC_ARGS,
 823       -1,
 824       KERN_PROC_PATHNAME,
 825   };
 826   char path[400];
 827   uptr len;
 828
 829   len = sizeof(path);
 830   if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1)
 831     pathname = path;
 832 #elif SANITIZER_SOLARIS
 833   pathname = getexecname();
 834   CHECK_NE(pathname, NULL);
 835 #elif SANITIZER_USE_GETAUXVAL
 836   // Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that
 837   // rely on that will fail to load shared libraries. Query AT_EXECFN instead.
 838   pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN));
 839 #endif
 840
 841   uptr rv = internal_execve(pathname, GetArgv(), GetEnviron());
 842   int rverrno;
 843   CHECK_EQ(internal_iserror(rv, &rverrno), true);
 844   Printf("execve failed, errno %d\n", rverrno);
 845   Die();
 846 }
 847 #endif  // !SANITIZER_OPENBSD
 848
 849 } // namespace __sanitizer
 850
 851 #endif