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_getauxval.h"
25#  include "sanitizer_glibc_version.h"
26#  include "sanitizer_linux.h"
27#  include "sanitizer_placement_new.h"
28#  include "sanitizer_procmaps.h"
29#  include "sanitizer_solaris.h"
30
31#  if SANITIZER_NETBSD
32#    define _RTLD_SOURCE  // for __lwp_gettcb_fast() / __lwp_getprivate_fast()
33#  endif
34
35#  include <dlfcn.h>  // for dlsym()
36#  include <link.h>
37#  include <pthread.h>
38#  include <signal.h>
39#  include <sys/mman.h>
40#  include <sys/resource.h>
41#  include <syslog.h>
42
43#  if !defined(ElfW)
44#    define ElfW(type) Elf_##type
45#  endif
46
47#  if SANITIZER_FREEBSD
48#    include <pthread_np.h>
49#    include <sys/auxv.h>
50#    include <sys/sysctl.h>
51#    define pthread_getattr_np pthread_attr_get_np
52// The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
53// that, it was never implemented. So just define it to zero.
54#    undef MAP_NORESERVE
55#    define MAP_NORESERVE 0
56extern const Elf_Auxinfo *__elf_aux_vector __attribute__ ((weak));
57#  endif
58
59#  if SANITIZER_NETBSD
60#    include <lwp.h>
61#    include <sys/sysctl.h>
62#    include <sys/tls.h>
63#  endif
64
65#  if SANITIZER_SOLARIS
66#    include <stddef.h>
67#    include <stdlib.h>
68#    include <thread.h>
69#  endif
70
71#  if SANITIZER_ANDROID
72#    include <android/api-level.h>
73#    if !defined(CPU_COUNT) && !defined(__aarch64__)
74#      include <dirent.h>
75#      include <fcntl.h>
76struct __sanitizer::linux_dirent {
77  long d_ino;
78  off_t d_off;
79  unsigned short d_reclen;
80  char d_name[];
81};
82#    endif
83#  endif
84
85#  if !SANITIZER_ANDROID
86#    include <elf.h>
87#    include <unistd.h>
88#  endif
89
90namespace __sanitizer {
91
92SANITIZER_WEAK_ATTRIBUTE int real_sigaction(int signum, const void *act,
93                                            void *oldact);
94
95int internal_sigaction(int signum, const void *act, void *oldact) {
96#  if !SANITIZER_GO
97  if (&real_sigaction)
98    return real_sigaction(signum, act, oldact);
99#  endif
100  return sigaction(signum, (const struct sigaction *)act,
101                   (struct sigaction *)oldact);
102}
103
104void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
105                                uptr *stack_bottom) {
106  CHECK(stack_top);
107  CHECK(stack_bottom);
108  if (at_initialization) {
109    // This is the main thread. Libpthread may not be initialized yet.
110    struct rlimit rl;
111    CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
112
113    // Find the mapping that contains a stack variable.
114    MemoryMappingLayout proc_maps(/*cache_enabled*/ true);
115    if (proc_maps.Error()) {
116      *stack_top = *stack_bottom = 0;
117      return;
118    }
119    MemoryMappedSegment segment;
120    uptr prev_end = 0;
121    while (proc_maps.Next(&segment)) {
122      if ((uptr)&rl < segment.end)
123        break;
124      prev_end = segment.end;
125    }
126    CHECK((uptr)&rl >= segment.start && (uptr)&rl < segment.end);
127
128    // Get stacksize from rlimit, but clip it so that it does not overlap
129    // with other mappings.
130    uptr stacksize = rl.rlim_cur;
131    if (stacksize > segment.end - prev_end)
132      stacksize = segment.end - prev_end;
133    // When running with unlimited stack size, we still want to set some limit.
134    // The unlimited stack size is caused by 'ulimit -s unlimited'.
135    // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
136    if (stacksize > kMaxThreadStackSize)
137      stacksize = kMaxThreadStackSize;
138    *stack_top = segment.end;
139    *stack_bottom = segment.end - stacksize;
140    return;
141  }
142  uptr stacksize = 0;
143  void *stackaddr = nullptr;
144#  if SANITIZER_SOLARIS
145  stack_t ss;
146  CHECK_EQ(thr_stksegment(&ss), 0);
147  stacksize = ss.ss_size;
148  stackaddr = (char *)ss.ss_sp - stacksize;
149#  else   // !SANITIZER_SOLARIS
150  pthread_attr_t attr;
151  pthread_attr_init(&attr);
152  CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
153  internal_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
154  pthread_attr_destroy(&attr);
155#  endif  // SANITIZER_SOLARIS
156
157  *stack_top = (uptr)stackaddr + stacksize;
158  *stack_bottom = (uptr)stackaddr;
159}
160
161#  if !SANITIZER_GO
162bool SetEnv(const char *name, const char *value) {
163  void *f = dlsym(RTLD_NEXT, "setenv");
164  if (!f)
165    return false;
166  typedef int (*setenv_ft)(const char *name, const char *value, int overwrite);
167  setenv_ft setenv_f;
168  CHECK_EQ(sizeof(setenv_f), sizeof(f));
169  internal_memcpy(&setenv_f, &f, sizeof(f));
170  return setenv_f(name, value, 1) == 0;
171}
172#  endif
173
174__attribute__((unused)) static bool GetLibcVersion(int *major, int *minor,
175                                                   int *patch) {
176#  ifdef _CS_GNU_LIBC_VERSION
177  char buf[64];
178  uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
179  if (len >= sizeof(buf))
180    return false;
181  buf[len] = 0;
182  static const char kGLibC[] = "glibc ";
183  if (internal_strncmp(buf, kGLibC, sizeof(kGLibC) - 1) != 0)
184    return false;
185  const char *p = buf + sizeof(kGLibC) - 1;
186  *major = internal_simple_strtoll(p, &p, 10);
187  *minor = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
188  *patch = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
189  return true;
190#  else
191  return false;
192#  endif
193}
194
195// True if we can use dlpi_tls_data. glibc before 2.25 may leave NULL (BZ
196// #19826) so dlpi_tls_data cannot be used.
197//
198// musl before 1.2.3 and FreeBSD as of 12.2 incorrectly set dlpi_tls_data to
199// the TLS initialization image
200// https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254774
201__attribute__((unused)) static int g_use_dlpi_tls_data;
202
203#  if SANITIZER_GLIBC && !SANITIZER_GO
204__attribute__((unused)) static size_t g_tls_size;
205void InitTlsSize() {
206  int major, minor, patch;
207  g_use_dlpi_tls_data =
208      GetLibcVersion(&major, &minor, &patch) && major == 2 && minor >= 25;
209
210#    if defined(__aarch64__) || defined(__x86_64__) || \
211        defined(__powerpc64__) || defined(__loongarch__)
212  void *get_tls_static_info = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
213  size_t tls_align;
214  ((void (*)(size_t *, size_t *))get_tls_static_info)(&g_tls_size, &tls_align);
215#    endif
216}
217#  else
218void InitTlsSize() {}
219#  endif  // SANITIZER_GLIBC && !SANITIZER_GO
220
221// On glibc x86_64, ThreadDescriptorSize() needs to be precise due to the usage
222// of g_tls_size. On other targets, ThreadDescriptorSize() is only used by lsan
223// to get the pointer to thread-specific data keys in the thread control block.
224#  if (SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS) && \
225      !SANITIZER_ANDROID && !SANITIZER_GO
226// sizeof(struct pthread) from glibc.
227static atomic_uintptr_t thread_descriptor_size;
228
229static uptr ThreadDescriptorSizeFallback() {
230  uptr val = 0;
231#    if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
232  int major;
233  int minor;
234  int patch;
235  if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
236    /* sizeof(struct pthread) values from various glibc versions.  */
237    if (SANITIZER_X32)
238      val = 1728;  // Assume only one particular version for x32.
239    // For ARM sizeof(struct pthread) changed in Glibc 2.23.
240    else if (SANITIZER_ARM)
241      val = minor <= 22 ? 1120 : 1216;
242    else if (minor <= 3)
243      val = FIRST_32_SECOND_64(1104, 1696);
244    else if (minor == 4)
245      val = FIRST_32_SECOND_64(1120, 1728);
246    else if (minor == 5)
247      val = FIRST_32_SECOND_64(1136, 1728);
248    else if (minor <= 9)
249      val = FIRST_32_SECOND_64(1136, 1712);
250    else if (minor == 10)
251      val = FIRST_32_SECOND_64(1168, 1776);
252    else if (minor == 11 || (minor == 12 && patch == 1))
253      val = FIRST_32_SECOND_64(1168, 2288);
254    else if (minor <= 14)
255      val = FIRST_32_SECOND_64(1168, 2304);
256    else if (minor < 32)  // Unknown version
257      val = FIRST_32_SECOND_64(1216, 2304);
258    else  // minor == 32
259      val = FIRST_32_SECOND_64(1344, 2496);
260  }
261#    elif defined(__s390__) || defined(__sparc__)
262  // The size of a prefix of TCB including pthread::{specific_1stblock,specific}
263  // suffices. Just return offsetof(struct pthread, specific_used), which hasn't
264  // changed since 2007-05. Technically this applies to i386/x86_64 as well but
265  // we call _dl_get_tls_static_info and need the precise size of struct
266  // pthread.
267  return FIRST_32_SECOND_64(524, 1552);
268#    elif defined(__mips__)
269  // TODO(sagarthakur): add more values as per different glibc versions.
270  val = FIRST_32_SECOND_64(1152, 1776);
271#    elif SANITIZER_LOONGARCH64
272  val = 1856;  // from glibc 2.36
273#    elif SANITIZER_RISCV64
274  int major;
275  int minor;
276  int patch;
277  if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
278    // TODO: consider adding an optional runtime check for an unknown (untested)
279    // glibc version
280    if (minor <= 28)  // WARNING: the highest tested version is 2.29
281      val = 1772;     // no guarantees for this one
282    else if (minor <= 31)
283      val = 1772;  // tested against glibc 2.29, 2.31
284    else
285      val = 1936;  // tested against glibc 2.32
286  }
287
288#    elif defined(__aarch64__)
289  // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
290  val = 1776;
291#    elif defined(__powerpc64__)
292  val = 1776;  // from glibc.ppc64le 2.20-8.fc21
293#    endif
294  return val;
295}
296
297uptr ThreadDescriptorSize() {
298  uptr val = atomic_load_relaxed(&thread_descriptor_size);
299  if (val)
300    return val;
301  // _thread_db_sizeof_pthread is a GLIBC_PRIVATE symbol that is exported in
302  // glibc 2.34 and later.
303  if (unsigned *psizeof = static_cast<unsigned *>(
304          dlsym(RTLD_DEFAULT, "_thread_db_sizeof_pthread")))
305    val = *psizeof;
306  if (!val)
307    val = ThreadDescriptorSizeFallback();
308  atomic_store_relaxed(&thread_descriptor_size, val);
309  return val;
310}
311
312#    if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64 || \
313        SANITIZER_LOONGARCH64
314// TlsPreTcbSize includes size of struct pthread_descr and size of tcb
315// head structure. It lies before the static tls blocks.
316static uptr TlsPreTcbSize() {
317#      if defined(__mips__)
318  const uptr kTcbHead = 16;  // sizeof (tcbhead_t)
319#      elif defined(__powerpc64__)
320  const uptr kTcbHead = 88;  // sizeof (tcbhead_t)
321#      elif SANITIZER_RISCV64
322  const uptr kTcbHead = 16;  // sizeof (tcbhead_t)
323#      elif SANITIZER_LOONGARCH64
324  const uptr kTcbHead = 16;  // sizeof (tcbhead_t)
325#      endif
326  const uptr kTlsAlign = 16;
327  const uptr kTlsPreTcbSize =
328      RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign);
329  return kTlsPreTcbSize;
330}
331#    endif
332
333namespace {
334struct TlsBlock {
335  uptr begin, end, align;
336  size_t tls_modid;
337  bool operator<(const TlsBlock &rhs) const { return begin < rhs.begin; }
338};
339}  // namespace
340
341#    ifdef __s390__
342extern "C" uptr __tls_get_offset(void *arg);
343
344static uptr TlsGetOffset(uptr ti_module, uptr ti_offset) {
345  // The __tls_get_offset ABI requires %r12 to point to GOT and %r2 to be an
346  // offset of a struct tls_index inside GOT. We don't possess either of the
347  // two, so violate the letter of the "ELF Handling For Thread-Local
348  // Storage" document and assume that the implementation just dereferences
349  // %r2 + %r12.
350  uptr tls_index[2] = {ti_module, ti_offset};
351  register uptr r2 asm("2") = 0;
352  register void *r12 asm("12") = tls_index;
353  asm("basr %%r14, %[__tls_get_offset]"
354      : "+r"(r2)
355      : [__tls_get_offset] "r"(__tls_get_offset), "r"(r12)
356      : "memory", "cc", "0", "1", "3", "4", "5", "14");
357  return r2;
358}
359#    else
360extern "C" void *__tls_get_addr(size_t *);
361#    endif
362
363static size_t main_tls_modid;
364
365static int CollectStaticTlsBlocks(struct dl_phdr_info *info, size_t size,
366                                  void *data) {
367  size_t tls_modid;
368#    if SANITIZER_SOLARIS
369  // dlpi_tls_modid is only available since Solaris 11.4 SRU 10.  Use
370  // dlinfo(RTLD_DI_LINKMAP) instead which works on all of Solaris 11.3,
371  // 11.4, and Illumos.  The tlsmodid of the executable was changed to 1 in
372  // 11.4 to match other implementations.
373  if (size >= offsetof(dl_phdr_info_test, dlpi_tls_modid))
374    main_tls_modid = 1;
375  else
376    main_tls_modid = 0;
377  g_use_dlpi_tls_data = 0;
378  Rt_map *map;
379  dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &map);
380  tls_modid = map->rt_tlsmodid;
381#    else
382  main_tls_modid = 1;
383  tls_modid = info->dlpi_tls_modid;
384#    endif
385
386  if (tls_modid < main_tls_modid)
387    return 0;
388  uptr begin;
389#    if !SANITIZER_SOLARIS
390  begin = (uptr)info->dlpi_tls_data;
391#    endif
392  if (!g_use_dlpi_tls_data) {
393    // Call __tls_get_addr as a fallback. This forces TLS allocation on glibc
394    // and FreeBSD.
395#    ifdef __s390__
396    begin = (uptr)__builtin_thread_pointer() + TlsGetOffset(tls_modid, 0);
397#    else
398    size_t mod_and_off[2] = {tls_modid, 0};
399    begin = (uptr)__tls_get_addr(mod_and_off);
400#    endif
401  }
402  for (unsigned i = 0; i != info->dlpi_phnum; ++i)
403    if (info->dlpi_phdr[i].p_type == PT_TLS) {
404      static_cast<InternalMmapVector<TlsBlock> *>(data)->push_back(
405          TlsBlock{begin, begin + info->dlpi_phdr[i].p_memsz,
406                   info->dlpi_phdr[i].p_align, tls_modid});
407      break;
408    }
409  return 0;
410}
411
412__attribute__((unused)) static void GetStaticTlsBoundary(uptr *addr, uptr *size,
413                                                         uptr *align) {
414  InternalMmapVector<TlsBlock> ranges;
415  dl_iterate_phdr(CollectStaticTlsBlocks, &ranges);
416  uptr len = ranges.size();
417  Sort(ranges.begin(), len);
418  // Find the range with tls_modid == main_tls_modid. For glibc, because
419  // libc.so uses PT_TLS, this module is guaranteed to exist and is one of
420  // the initially loaded modules.
421  uptr one = 0;
422  while (one != len && ranges[one].tls_modid != main_tls_modid) ++one;
423  if (one == len) {
424    // This may happen with musl if no module uses PT_TLS.
425    *addr = 0;
426    *size = 0;
427    *align = 1;
428    return;
429  }
430  // Find the maximum consecutive ranges. We consider two modules consecutive if
431  // the gap is smaller than the alignment of the latter range. The dynamic
432  // loader places static TLS blocks this way not to waste space.
433  uptr l = one;
434  *align = ranges[l].align;
435  while (l != 0 && ranges[l].begin < ranges[l - 1].end + ranges[l].align)
436    *align = Max(*align, ranges[--l].align);
437  uptr r = one + 1;
438  while (r != len && ranges[r].begin < ranges[r - 1].end + ranges[r].align)
439    *align = Max(*align, ranges[r++].align);
440  *addr = ranges[l].begin;
441  *size = ranges[r - 1].end - ranges[l].begin;
442}
443#  endif  // (x86_64 || i386 || mips || ...) && (SANITIZER_FREEBSD ||
444          // SANITIZER_LINUX) && !SANITIZER_ANDROID && !SANITIZER_GO
445
446#  if SANITIZER_NETBSD
447static struct tls_tcb *ThreadSelfTlsTcb() {
448  struct tls_tcb *tcb = nullptr;
449#    ifdef __HAVE___LWP_GETTCB_FAST
450  tcb = (struct tls_tcb *)__lwp_gettcb_fast();
451#    elif defined(__HAVE___LWP_GETPRIVATE_FAST)
452  tcb = (struct tls_tcb *)__lwp_getprivate_fast();
453#    endif
454  return tcb;
455}
456
457uptr ThreadSelf() { return (uptr)ThreadSelfTlsTcb()->tcb_pthread; }
458
459int GetSizeFromHdr(struct dl_phdr_info *info, size_t size, void *data) {
460  const Elf_Phdr *hdr = info->dlpi_phdr;
461  const Elf_Phdr *last_hdr = hdr + info->dlpi_phnum;
462
463  for (; hdr != last_hdr; ++hdr) {
464    if (hdr->p_type == PT_TLS && info->dlpi_tls_modid == 1) {
465      *(uptr *)data = hdr->p_memsz;
466      break;
467    }
468  }
469  return 0;
470}
471#  endif  // SANITIZER_NETBSD
472
473#  if SANITIZER_ANDROID
474// Bionic provides this API since S.
475extern "C" SANITIZER_WEAK_ATTRIBUTE void __libc_get_static_tls_bounds(void **,
476                                                                      void **);
477#  endif
478
479#  if !SANITIZER_GO
480static void GetTls(uptr *addr, uptr *size) {
481#    if SANITIZER_ANDROID
482  if (&__libc_get_static_tls_bounds) {
483    void *start_addr;
484    void *end_addr;
485    __libc_get_static_tls_bounds(&start_addr, &end_addr);
486    *addr = reinterpret_cast<uptr>(start_addr);
487    *size =
488        reinterpret_cast<uptr>(end_addr) - reinterpret_cast<uptr>(start_addr);
489  } else {
490    *addr = 0;
491    *size = 0;
492  }
493#    elif SANITIZER_GLIBC && defined(__x86_64__)
494  // For aarch64 and x86-64, use an O(1) approach which requires relatively
495  // precise ThreadDescriptorSize. g_tls_size was initialized in InitTlsSize.
496#      if SANITIZER_X32
497  asm("mov %%fs:8,%0" : "=r"(*addr));
498#      else
499  asm("mov %%fs:16,%0" : "=r"(*addr));
500#      endif
501  *size = g_tls_size;
502  *addr -= *size;
503  *addr += ThreadDescriptorSize();
504#    elif SANITIZER_GLIBC && defined(__aarch64__)
505  *addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
506          ThreadDescriptorSize();
507  *size = g_tls_size + ThreadDescriptorSize();
508#    elif SANITIZER_GLIBC && defined(__loongarch__)
509#      ifdef __clang__
510  *addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
511          ThreadDescriptorSize();
512#      else
513  asm("or %0,$tp,$zero" : "=r"(*addr));
514  *addr -= ThreadDescriptorSize();
515#      endif
516  *size = g_tls_size + ThreadDescriptorSize();
517#    elif SANITIZER_GLIBC && defined(__powerpc64__)
518  // Workaround for glibc<2.25(?). 2.27 is known to not need this.
519  uptr tp;
520  asm("addi %0,13,-0x7000" : "=r"(tp));
521  const uptr pre_tcb_size = TlsPreTcbSize();
522  *addr = tp - pre_tcb_size;
523  *size = g_tls_size + pre_tcb_size;
524#    elif SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS
525  uptr align;
526  GetStaticTlsBoundary(addr, size, &align);
527#      if defined(__x86_64__) || defined(__i386__) || defined(__s390__) || \
528          defined(__sparc__)
529  if (SANITIZER_GLIBC) {
530#        if defined(__x86_64__) || defined(__i386__)
531    align = Max<uptr>(align, 64);
532#        else
533    align = Max<uptr>(align, 16);
534#        endif
535  }
536  const uptr tp = RoundUpTo(*addr + *size, align);
537
538  // lsan requires the range to additionally cover the static TLS surplus
539  // (elf/dl-tls.c defines 1664). Otherwise there may be false positives for
540  // allocations only referenced by tls in dynamically loaded modules.
541  if (SANITIZER_GLIBC)
542    *size += 1644;
543  else if (SANITIZER_FREEBSD)
544    *size += 128;  // RTLD_STATIC_TLS_EXTRA
545
546  // Extend the range to include the thread control block. On glibc, lsan needs
547  // the range to include pthread::{specific_1stblock,specific} so that
548  // allocations only referenced by pthread_setspecific can be scanned. This may
549  // underestimate by at most TLS_TCB_ALIGN-1 bytes but it should be fine
550  // because the number of bytes after pthread::specific is larger.
551  *addr = tp - RoundUpTo(*size, align);
552  *size = tp - *addr + ThreadDescriptorSize();
553#      else
554  if (SANITIZER_GLIBC)
555    *size += 1664;
556  else if (SANITIZER_FREEBSD)
557    *size += 128;  // RTLD_STATIC_TLS_EXTRA
558#        if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64
559  const uptr pre_tcb_size = TlsPreTcbSize();
560  *addr -= pre_tcb_size;
561  *size += pre_tcb_size;
562#        else
563  // arm and aarch64 reserve two words at TP, so this underestimates the range.
564  // However, this is sufficient for the purpose of finding the pointers to
565  // thread-specific data keys.
566  const uptr tcb_size = ThreadDescriptorSize();
567  *addr -= tcb_size;
568  *size += tcb_size;
569#        endif
570#      endif
571#    elif SANITIZER_NETBSD
572  struct tls_tcb *const tcb = ThreadSelfTlsTcb();
573  *addr = 0;
574  *size = 0;
575  if (tcb != 0) {
576    // Find size (p_memsz) of dlpi_tls_modid 1 (TLS block of the main program).
577    // ld.elf_so hardcodes the index 1.
578    dl_iterate_phdr(GetSizeFromHdr, size);
579
580    if (*size != 0) {
581      // The block has been found and tcb_dtv[1] contains the base address
582      *addr = (uptr)tcb->tcb_dtv[1];
583    }
584  }
585#    else
586#      error "Unknown OS"
587#    endif
588}
589#  endif
590
591#  if !SANITIZER_GO
592uptr GetTlsSize() {
593#    if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
594        SANITIZER_SOLARIS
595  uptr addr, size;
596  GetTls(&addr, &size);
597  return size;
598#    else
599  return 0;
600#    endif
601}
602#  endif
603
604void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
605                          uptr *tls_addr, uptr *tls_size) {
606#  if SANITIZER_GO
607  // Stub implementation for Go.
608  *stk_addr = *stk_size = *tls_addr = *tls_size = 0;
609#  else
610  GetTls(tls_addr, tls_size);
611
612  uptr stack_top, stack_bottom;
613  GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
614  *stk_addr = stack_bottom;
615  *stk_size = stack_top - stack_bottom;
616
617  if (!main) {
618    // If stack and tls intersect, make them non-intersecting.
619    if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
620      if (*stk_addr + *stk_size < *tls_addr + *tls_size)
621        *tls_size = *stk_addr + *stk_size - *tls_addr;
622      *stk_size = *tls_addr - *stk_addr;
623    }
624  }
625#  endif
626}
627
628#  if !SANITIZER_FREEBSD
629typedef ElfW(Phdr) Elf_Phdr;
630#  endif
631
632struct DlIteratePhdrData {
633  InternalMmapVectorNoCtor<LoadedModule> *modules;
634  bool first;
635};
636
637static int AddModuleSegments(const char *module_name, dl_phdr_info *info,
638                             InternalMmapVectorNoCtor<LoadedModule> *modules) {
639  if (module_name[0] == '\0')
640    return 0;
641  LoadedModule cur_module;
642  cur_module.set(module_name, info->dlpi_addr);
643  for (int i = 0; i < (int)info->dlpi_phnum; i++) {
644    const Elf_Phdr *phdr = &info->dlpi_phdr[i];
645    if (phdr->p_type == PT_LOAD) {
646      uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
647      uptr cur_end = cur_beg + phdr->p_memsz;
648      bool executable = phdr->p_flags & PF_X;
649      bool writable = phdr->p_flags & PF_W;
650      cur_module.addAddressRange(cur_beg, cur_end, executable, writable);
651    } else if (phdr->p_type == PT_NOTE) {
652#  ifdef NT_GNU_BUILD_ID
653      uptr off = 0;
654      while (off + sizeof(ElfW(Nhdr)) < phdr->p_memsz) {
655        auto *nhdr = reinterpret_cast<const ElfW(Nhdr) *>(info->dlpi_addr +
656                                                          phdr->p_vaddr + off);
657        constexpr auto kGnuNamesz = 4;  // "GNU" with NUL-byte.
658        static_assert(kGnuNamesz % 4 == 0, "kGnuNameSize is aligned to 4.");
659        if (nhdr->n_type == NT_GNU_BUILD_ID && nhdr->n_namesz == kGnuNamesz) {
660          if (off + sizeof(ElfW(Nhdr)) + nhdr->n_namesz + nhdr->n_descsz >
661              phdr->p_memsz) {
662            // Something is very wrong, bail out instead of reading potentially
663            // arbitrary memory.
664            break;
665          }
666          const char *name =
667              reinterpret_cast<const char *>(nhdr) + sizeof(*nhdr);
668          if (internal_memcmp(name, "GNU", 3) == 0) {
669            const char *value = reinterpret_cast<const char *>(nhdr) +
670                                sizeof(*nhdr) + kGnuNamesz;
671            cur_module.setUuid(value, nhdr->n_descsz);
672            break;
673          }
674        }
675        off += sizeof(*nhdr) + RoundUpTo(nhdr->n_namesz, 4) +
676               RoundUpTo(nhdr->n_descsz, 4);
677      }
678#  endif
679    }
680  }
681  modules->push_back(cur_module);
682  return 0;
683}
684
685static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
686  DlIteratePhdrData *data = (DlIteratePhdrData *)arg;
687  if (data->first) {
688    InternalMmapVector<char> module_name(kMaxPathLength);
689    data->first = false;
690    // First module is the binary itself.
691    ReadBinaryNameCached(module_name.data(), module_name.size());
692    return AddModuleSegments(module_name.data(), info, data->modules);
693  }
694
695  if (info->dlpi_name)
696    return AddModuleSegments(info->dlpi_name, info, data->modules);
697
698  return 0;
699}
700
701#  if SANITIZER_ANDROID && __ANDROID_API__ < 21
702extern "C" __attribute__((weak)) int dl_iterate_phdr(
703    int (*)(struct dl_phdr_info *, size_t, void *), void *);
704#  endif
705
706static bool requiresProcmaps() {
707#  if SANITIZER_ANDROID && __ANDROID_API__ <= 22
708  // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
709  // The runtime check allows the same library to work with
710  // both K and L (and future) Android releases.
711  return AndroidGetApiLevel() <= ANDROID_LOLLIPOP_MR1;
712#  else
713  return false;
714#  endif
715}
716
717static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) {
718  MemoryMappingLayout memory_mapping(/*cache_enabled*/ true);
719  memory_mapping.DumpListOfModules(modules);
720}
721
722void ListOfModules::init() {
723  clearOrInit();
724  if (requiresProcmaps()) {
725    procmapsInit(&modules_);
726  } else {
727    DlIteratePhdrData data = {&modules_, true};
728    dl_iterate_phdr(dl_iterate_phdr_cb, &data);
729  }
730}
731
732// When a custom loader is used, dl_iterate_phdr may not contain the full
733// list of modules. Allow callers to fall back to using procmaps.
734void ListOfModules::fallbackInit() {
735  if (!requiresProcmaps()) {
736    clearOrInit();
737    procmapsInit(&modules_);
738  } else {
739    clear();
740  }
741}
742
743// getrusage does not give us the current RSS, only the max RSS.
744// Still, this is better than nothing if /proc/self/statm is not available
745// for some reason, e.g. due to a sandbox.
746static uptr GetRSSFromGetrusage() {
747  struct rusage usage;
748  if (getrusage(RUSAGE_SELF, &usage))  // Failed, probably due to a sandbox.
749    return 0;
750  return usage.ru_maxrss << 10;  // ru_maxrss is in Kb.
751}
752
753uptr GetRSS() {
754  if (!common_flags()->can_use_proc_maps_statm)
755    return GetRSSFromGetrusage();
756  fd_t fd = OpenFile("/proc/self/statm", RdOnly);
757  if (fd == kInvalidFd)
758    return GetRSSFromGetrusage();
759  char buf[64];
760  uptr len = internal_read(fd, buf, sizeof(buf) - 1);
761  internal_close(fd);
762  if ((sptr)len <= 0)
763    return 0;
764  buf[len] = 0;
765  // The format of the file is:
766  // 1084 89 69 11 0 79 0
767  // We need the second number which is RSS in pages.
768  char *pos = buf;
769  // Skip the first number.
770  while (*pos >= '0' && *pos <= '9') pos++;
771  // Skip whitespaces.
772  while (!(*pos >= '0' && *pos <= '9') && *pos != 0) pos++;
773  // Read the number.
774  uptr rss = 0;
775  while (*pos >= '0' && *pos <= '9') rss = rss * 10 + *pos++ - '0';
776  return rss * GetPageSizeCached();
777}
778
779// sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used on most platforms as
780// they allocate memory.
781u32 GetNumberOfCPUs() {
782#  if SANITIZER_FREEBSD || SANITIZER_NETBSD
783  u32 ncpu;
784  int req[2];
785  uptr len = sizeof(ncpu);
786  req[0] = CTL_HW;
787  req[1] = HW_NCPU;
788  CHECK_EQ(internal_sysctl(req, 2, &ncpu, &len, NULL, 0), 0);
789  return ncpu;
790#  elif SANITIZER_ANDROID && !defined(CPU_COUNT) && !defined(__aarch64__)
791  // Fall back to /sys/devices/system/cpu on Android when cpu_set_t doesn't
792  // exist in sched.h. That is the case for toolchains generated with older
793  // NDKs.
794  // This code doesn't work on AArch64 because internal_getdents makes use of
795  // the 64bit getdents syscall, but cpu_set_t seems to always exist on AArch64.
796  uptr fd = internal_open("/sys/devices/system/cpu", O_RDONLY | O_DIRECTORY);
797  if (internal_iserror(fd))
798    return 0;
799  InternalMmapVector<u8> buffer(4096);
800  uptr bytes_read = buffer.size();
801  uptr n_cpus = 0;
802  u8 *d_type;
803  struct linux_dirent *entry = (struct linux_dirent *)&buffer[bytes_read];
804  while (true) {
805    if ((u8 *)entry >= &buffer[bytes_read]) {
806      bytes_read = internal_getdents(fd, (struct linux_dirent *)buffer.data(),
807                                     buffer.size());
808      if (internal_iserror(bytes_read) || !bytes_read)
809        break;
810      entry = (struct linux_dirent *)buffer.data();
811    }
812    d_type = (u8 *)entry + entry->d_reclen - 1;
813    if (d_type >= &buffer[bytes_read] ||
814        (u8 *)&entry->d_name[3] >= &buffer[bytes_read])
815      break;
816    if (entry->d_ino != 0 && *d_type == DT_DIR) {
817      if (entry->d_name[0] == 'c' && entry->d_name[1] == 'p' &&
818          entry->d_name[2] == 'u' && entry->d_name[3] >= '0' &&
819          entry->d_name[3] <= '9')
820        n_cpus++;
821    }
822    entry = (struct linux_dirent *)(((u8 *)entry) + entry->d_reclen);
823  }
824  internal_close(fd);
825  return n_cpus;
826#  elif SANITIZER_SOLARIS
827  return sysconf(_SC_NPROCESSORS_ONLN);
828#  else
829  cpu_set_t CPUs;
830  CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
831  return CPU_COUNT(&CPUs);
832#  endif
833}
834
835#  if SANITIZER_LINUX
836
837#    if SANITIZER_ANDROID
838static atomic_uint8_t android_log_initialized;
839
840void AndroidLogInit() {
841  openlog(GetProcessName(), 0, LOG_USER);
842  atomic_store(&android_log_initialized, 1, memory_order_release);
843}
844
845static bool ShouldLogAfterPrintf() {
846  return atomic_load(&android_log_initialized, memory_order_acquire);
847}
848
849extern "C" SANITIZER_WEAK_ATTRIBUTE int async_safe_write_log(int pri,
850                                                             const char *tag,
851                                                             const char *msg);
852extern "C" SANITIZER_WEAK_ATTRIBUTE int __android_log_write(int prio,
853                                                            const char *tag,
854                                                            const char *msg);
855
856// ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
857#      define SANITIZER_ANDROID_LOG_INFO 4
858
859// async_safe_write_log is a new public version of __libc_write_log that is
860// used behind syslog. It is preferable to syslog as it will not do any dynamic
861// memory allocation or formatting.
862// If the function is not available, syslog is preferred for L+ (it was broken
863// pre-L) as __android_log_write triggers a racey behavior with the strncpy
864// interceptor. Fallback to __android_log_write pre-L.
865void WriteOneLineToSyslog(const char *s) {
866  if (&async_safe_write_log) {
867    async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
868  } else if (AndroidGetApiLevel() > ANDROID_KITKAT) {
869    syslog(LOG_INFO, "%s", s);
870  } else {
871    CHECK(&__android_log_write);
872    __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
873  }
874}
875
876extern "C" SANITIZER_WEAK_ATTRIBUTE void android_set_abort_message(
877    const char *);
878
879void SetAbortMessage(const char *str) {
880  if (&android_set_abort_message)
881    android_set_abort_message(str);
882}
883#    else
884void AndroidLogInit() {}
885
886static bool ShouldLogAfterPrintf() { return true; }
887
888void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
889
890void SetAbortMessage(const char *str) {}
891#    endif  // SANITIZER_ANDROID
892
893void LogMessageOnPrintf(const char *str) {
894  if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
895    WriteToSyslog(str);
896}
897
898#  endif  // SANITIZER_LINUX
899
900#  if SANITIZER_GLIBC && !SANITIZER_GO
901// glibc crashes when using clock_gettime from a preinit_array function as the
902// vDSO function pointers haven't been initialized yet. __progname is
903// initialized after the vDSO function pointers, so if it exists, is not null
904// and is not empty, we can use clock_gettime.
905extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname;
906inline bool CanUseVDSO() { return &__progname && __progname && *__progname; }
907
908// MonotonicNanoTime is a timing function that can leverage the vDSO by calling
909// clock_gettime. real_clock_gettime only exists if clock_gettime is
910// intercepted, so define it weakly and use it if available.
911extern "C" SANITIZER_WEAK_ATTRIBUTE int real_clock_gettime(u32 clk_id,
912                                                           void *tp);
913u64 MonotonicNanoTime() {
914  timespec ts;
915  if (CanUseVDSO()) {
916    if (&real_clock_gettime)
917      real_clock_gettime(CLOCK_MONOTONIC, &ts);
918    else
919      clock_gettime(CLOCK_MONOTONIC, &ts);
920  } else {
921    internal_clock_gettime(CLOCK_MONOTONIC, &ts);
922  }
923  return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
924}
925#  else
926// Non-glibc & Go always use the regular function.
927u64 MonotonicNanoTime() {
928  timespec ts;
929  clock_gettime(CLOCK_MONOTONIC, &ts);
930  return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
931}
932#  endif  // SANITIZER_GLIBC && !SANITIZER_GO
933
934void ReExec() {
935  const char *pathname = "/proc/self/exe";
936
937#  if SANITIZER_FREEBSD
938  for (const auto *aux = __elf_aux_vector; aux->a_type != AT_NULL; aux++) {
939    if (aux->a_type == AT_EXECPATH) {
940      pathname = static_cast<const char *>(aux->a_un.a_ptr);
941      break;
942    }
943  }
944#  elif SANITIZER_NETBSD
945  static const int name[] = {
946      CTL_KERN,
947      KERN_PROC_ARGS,
948      -1,
949      KERN_PROC_PATHNAME,
950  };
951  char path[400];
952  uptr len;
953
954  len = sizeof(path);
955  if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1)
956    pathname = path;
957#  elif SANITIZER_SOLARIS
958  pathname = getexecname();
959  CHECK_NE(pathname, NULL);
960#  elif SANITIZER_USE_GETAUXVAL
961  // Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that
962  // rely on that will fail to load shared libraries. Query AT_EXECFN instead.
963  pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN));
964#  endif
965
966  uptr rv = internal_execve(pathname, GetArgv(), GetEnviron());
967  int rverrno;
968  CHECK_EQ(internal_iserror(rv, &rverrno), true);
969  Printf("execve failed, errno %d\n", rverrno);
970  Die();
971}
972
973void UnmapFromTo(uptr from, uptr to) {
974  if (to == from)
975    return;
976  CHECK(to >= from);
977  uptr res = internal_munmap(reinterpret_cast<void *>(from), to - from);
978  if (UNLIKELY(internal_iserror(res))) {
979    Report("ERROR: %s failed to unmap 0x%zx (%zd) bytes at address %p\n",
980           SanitizerToolName, to - from, to - from, (void *)from);
981    CHECK("unable to unmap" && 0);
982  }
983}
984
985uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
986                      uptr min_shadow_base_alignment,
987                      UNUSED uptr &high_mem_end) {
988  const uptr granularity = GetMmapGranularity();
989  const uptr alignment =
990      Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
991  const uptr left_padding =
992      Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);
993
994  const uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity);
995  const uptr map_size = shadow_size + left_padding + alignment;
996
997  const uptr map_start = (uptr)MmapNoAccess(map_size);
998  CHECK_NE(map_start, ~(uptr)0);
999
1000  const uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
1001
1002  UnmapFromTo(map_start, shadow_start - left_padding);
1003  UnmapFromTo(shadow_start + shadow_size, map_start + map_size);
1004
1005  return shadow_start;
1006}
1007
1008static uptr MmapSharedNoReserve(uptr addr, uptr size) {
1009  return internal_mmap(
1010      reinterpret_cast<void *>(addr), size, PROT_READ | PROT_WRITE,
1011      MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
1012}
1013
1014static uptr MremapCreateAlias(uptr base_addr, uptr alias_addr,
1015                              uptr alias_size) {
1016#  if SANITIZER_LINUX
1017  return internal_mremap(reinterpret_cast<void *>(base_addr), 0, alias_size,
1018                         MREMAP_MAYMOVE | MREMAP_FIXED,
1019                         reinterpret_cast<void *>(alias_addr));
1020#  else
1021  CHECK(false && "mremap is not supported outside of Linux");
1022  return 0;
1023#  endif
1024}
1025
1026static void CreateAliases(uptr start_addr, uptr alias_size, uptr num_aliases) {
1027  uptr total_size = alias_size * num_aliases;
1028  uptr mapped = MmapSharedNoReserve(start_addr, total_size);
1029  CHECK_EQ(mapped, start_addr);
1030
1031  for (uptr i = 1; i < num_aliases; ++i) {
1032    uptr alias_addr = start_addr + i * alias_size;
1033    CHECK_EQ(MremapCreateAlias(start_addr, alias_addr, alias_size), alias_addr);
1034  }
1035}
1036
1037uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
1038                                uptr num_aliases, uptr ring_buffer_size) {
1039  CHECK_EQ(alias_size & (alias_size - 1), 0);
1040  CHECK_EQ(num_aliases & (num_aliases - 1), 0);
1041  CHECK_EQ(ring_buffer_size & (ring_buffer_size - 1), 0);
1042
1043  const uptr granularity = GetMmapGranularity();
1044  shadow_size = RoundUpTo(shadow_size, granularity);
1045  CHECK_EQ(shadow_size & (shadow_size - 1), 0);
1046
1047  const uptr alias_region_size = alias_size * num_aliases;
1048  const uptr alignment =
1049      2 * Max(Max(shadow_size, alias_region_size), ring_buffer_size);
1050  const uptr left_padding = ring_buffer_size;
1051
1052  const uptr right_size = alignment;
1053  const uptr map_size = left_padding + 2 * alignment;
1054
1055  const uptr map_start = reinterpret_cast<uptr>(MmapNoAccess(map_size));
1056  CHECK_NE(map_start, static_cast<uptr>(-1));
1057  const uptr right_start = RoundUpTo(map_start + left_padding, alignment);
1058
1059  UnmapFromTo(map_start, right_start - left_padding);
1060  UnmapFromTo(right_start + right_size, map_start + map_size);
1061
1062  CreateAliases(right_start + right_size / 2, alias_size, num_aliases);
1063
1064  return right_start;
1065}
1066
1067void InitializePlatformCommonFlags(CommonFlags *cf) {
1068#  if SANITIZER_ANDROID
1069  if (&__libc_get_static_tls_bounds == nullptr)
1070    cf->detect_leaks = false;
1071#  endif
1072}
1073
1074}  // namespace __sanitizer
1075
1076#endif
1077