1//===-- sanitizer_linux_libcdep.cc ----------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file is shared between AddressSanitizer and ThreadSanitizer
11// run-time libraries and implements linux-specific functions from
12// sanitizer_libc.h.
13//===----------------------------------------------------------------------===//
14
15#include "sanitizer_platform.h"
16
17#if SANITIZER_FREEBSD || SANITIZER_LINUX
18
19#include "sanitizer_allocator_internal.h"
20#include "sanitizer_atomic.h"
21#include "sanitizer_common.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#include "sanitizer_stacktrace.h"
28
29#if SANITIZER_ANDROID || SANITIZER_FREEBSD
30#include <dlfcn.h>  // for dlsym()
31#endif
32
33#include <link.h>
34#include <pthread.h>
35#include <signal.h>
36#include <sys/resource.h>
37
38#if SANITIZER_FREEBSD
39#include <pthread_np.h>
40#include <osreldate.h>
41#define pthread_getattr_np pthread_attr_get_np
42#endif
43
44#if SANITIZER_LINUX
45#include <sys/prctl.h>
46#endif
47
48#if SANITIZER_ANDROID
49#include <android/api-level.h>
50#endif
51
52#if SANITIZER_ANDROID && __ANDROID_API__ < 21
53#include <android/log.h>
54#else
55#include <syslog.h>
56#endif
57
58#if !SANITIZER_ANDROID
59#include <elf.h>
60#include <unistd.h>
61#endif
62
63namespace __sanitizer {
64
65SANITIZER_WEAK_ATTRIBUTE int
66real_sigaction(int signum, const void *act, void *oldact);
67
68int internal_sigaction(int signum, const void *act, void *oldact) {
69#if !SANITIZER_GO
70  if (&real_sigaction)
71    return real_sigaction(signum, act, oldact);
72#endif
73  return sigaction(signum, (const struct sigaction *)act,
74                   (struct sigaction *)oldact);
75}
76
77void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
78                                uptr *stack_bottom) {
79  CHECK(stack_top);
80  CHECK(stack_bottom);
81  if (at_initialization) {
82    // This is the main thread. Libpthread may not be initialized yet.
83    struct rlimit rl;
84    CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
85
86    // Find the mapping that contains a stack variable.
87    MemoryMappingLayout proc_maps(/*cache_enabled*/true);
88    uptr start, end, offset;
89    uptr prev_end = 0;
90    while (proc_maps.Next(&start, &end, &offset, nullptr, 0,
91          /* protection */nullptr)) {
92      if ((uptr)&rl < end)
93        break;
94      prev_end = end;
95    }
96    CHECK((uptr)&rl >= start && (uptr)&rl < end);
97
98    // Get stacksize from rlimit, but clip it so that it does not overlap
99    // with other mappings.
100    uptr stacksize = rl.rlim_cur;
101    if (stacksize > end - prev_end)
102      stacksize = end - prev_end;
103    // When running with unlimited stack size, we still want to set some limit.
104    // The unlimited stack size is caused by 'ulimit -s unlimited'.
105    // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
106    if (stacksize > kMaxThreadStackSize)
107      stacksize = kMaxThreadStackSize;
108    *stack_top = end;
109    *stack_bottom = end - stacksize;
110    return;
111  }
112  pthread_attr_t attr;
113  pthread_attr_init(&attr);
114  CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
115  uptr stacksize = 0;
116  void *stackaddr = nullptr;
117  my_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
118  pthread_attr_destroy(&attr);
119
120  CHECK_LE(stacksize, kMaxThreadStackSize);  // Sanity check.
121  *stack_top = (uptr)stackaddr + stacksize;
122  *stack_bottom = (uptr)stackaddr;
123}
124
125#if !SANITIZER_GO
126bool SetEnv(const char *name, const char *value) {
127  void *f = dlsym(RTLD_NEXT, "setenv");
128  if (!f)
129    return false;
130  typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
131  setenv_ft setenv_f;
132  CHECK_EQ(sizeof(setenv_f), sizeof(f));
133  internal_memcpy(&setenv_f, &f, sizeof(f));
134  return setenv_f(name, value, 1) == 0;
135}
136#endif
137
138bool SanitizerSetThreadName(const char *name) {
139#ifdef PR_SET_NAME
140  return 0 == prctl(PR_SET_NAME, (unsigned long)name, 0, 0, 0);  // NOLINT
141#else
142  return false;
143#endif
144}
145
146bool SanitizerGetThreadName(char *name, int max_len) {
147#ifdef PR_GET_NAME
148  char buff[17];
149  if (prctl(PR_GET_NAME, (unsigned long)buff, 0, 0, 0))  // NOLINT
150    return false;
151  internal_strncpy(name, buff, max_len);
152  name[max_len] = 0;
153  return true;
154#else
155  return false;
156#endif
157}
158
159#if !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO
160static uptr g_tls_size;
161#endif
162
163#ifdef __i386__
164# define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
165#else
166# define DL_INTERNAL_FUNCTION
167#endif
168
169#if defined(__mips__) || defined(__powerpc64__)
170// TlsPreTcbSize includes size of struct pthread_descr and size of tcb
171// head structure. It lies before the static tls blocks.
172static uptr TlsPreTcbSize() {
173# if defined(__mips__)
174  const uptr kTcbHead = 16; // sizeof (tcbhead_t)
175# elif defined(__powerpc64__)
176  const uptr kTcbHead = 88; // sizeof (tcbhead_t)
177# endif
178  const uptr kTlsAlign = 16;
179  const uptr kTlsPreTcbSize =
180    (ThreadDescriptorSize() + kTcbHead + kTlsAlign - 1) & ~(kTlsAlign - 1);
181  InitTlsSize();
182  g_tls_size = (g_tls_size + kTlsPreTcbSize + kTlsAlign -1) & ~(kTlsAlign - 1);
183  return kTlsPreTcbSize;
184}
185#endif
186
187void InitTlsSize() {
188#if !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO
189// all current supported platforms have 16 bytes stack alignment
190  const size_t kStackAlign = 16;
191  typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
192  get_tls_func get_tls;
193  void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
194  CHECK_EQ(sizeof(get_tls), sizeof(get_tls_static_info_ptr));
195  internal_memcpy(&get_tls, &get_tls_static_info_ptr,
196                  sizeof(get_tls_static_info_ptr));
197  CHECK_NE(get_tls, 0);
198  size_t tls_size = 0;
199  size_t tls_align = 0;
200  get_tls(&tls_size, &tls_align);
201  if (tls_align < kStackAlign)
202    tls_align = kStackAlign;
203  g_tls_size = RoundUpTo(tls_size, tls_align);
204#endif  // !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO
205}
206
207#if (defined(__x86_64__) || defined(__i386__) || defined(__mips__) \
208    || defined(__aarch64__) || defined(__powerpc64__)) \
209    && SANITIZER_LINUX && !SANITIZER_ANDROID
210// sizeof(struct pthread) from glibc.
211static atomic_uintptr_t kThreadDescriptorSize;
212
213uptr ThreadDescriptorSize() {
214  uptr val = atomic_load(&kThreadDescriptorSize, memory_order_relaxed);
215  if (val)
216    return val;
217#if defined(__x86_64__) || defined(__i386__)
218#ifdef _CS_GNU_LIBC_VERSION
219  char buf[64];
220  uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
221  if (len < sizeof(buf) && internal_strncmp(buf, "glibc 2.", 8) == 0) {
222    char *end;
223    int minor = internal_simple_strtoll(buf + 8, &end, 10);
224    if (end != buf + 8 && (*end == '\0' || *end == '.')) {
225      /* sizeof(struct pthread) values from various glibc versions.  */
226      if (SANITIZER_X32)
227        val = 1728;  // Assume only one particular version for x32.
228      else if (minor <= 3)
229        val = FIRST_32_SECOND_64(1104, 1696);
230      else if (minor == 4)
231        val = FIRST_32_SECOND_64(1120, 1728);
232      else if (minor == 5)
233        val = FIRST_32_SECOND_64(1136, 1728);
234      else if (minor <= 9)
235        val = FIRST_32_SECOND_64(1136, 1712);
236      else if (minor == 10)
237        val = FIRST_32_SECOND_64(1168, 1776);
238      else if (minor <= 12)
239        val = FIRST_32_SECOND_64(1168, 2288);
240      else if (minor == 13)
241        val = FIRST_32_SECOND_64(1168, 2304);
242      else
243        val = FIRST_32_SECOND_64(1216, 2304);
244    }
245    if (val)
246      atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
247    return val;
248  }
249#endif
250#elif defined(__mips__)
251  // TODO(sagarthakur): add more values as per different glibc versions.
252  val = FIRST_32_SECOND_64(1152, 1776);
253  if (val)
254    atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
255  return val;
256#elif defined(__aarch64__)
257  // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
258  val = 1776;
259  atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
260  return val;
261#elif defined(__powerpc64__)
262  val = 1776; // from glibc.ppc64le 2.20-8.fc21
263  atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
264  return val;
265#endif
266  return 0;
267}
268
269// The offset at which pointer to self is located in the thread descriptor.
270const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
271
272uptr ThreadSelfOffset() {
273  return kThreadSelfOffset;
274}
275
276uptr ThreadSelf() {
277  uptr descr_addr;
278# if defined(__i386__)
279  asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
280# elif defined(__x86_64__)
281  asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
282# elif defined(__mips__)
283  // MIPS uses TLS variant I. The thread pointer (in hardware register $29)
284  // points to the end of the TCB + 0x7000. The pthread_descr structure is
285  // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
286  // TCB and the size of pthread_descr.
287  const uptr kTlsTcbOffset = 0x7000;
288  uptr thread_pointer;
289  asm volatile(".set push;\
290                .set mips64r2;\
291                rdhwr %0,$29;\
292                .set pop" : "=r" (thread_pointer));
293  descr_addr = thread_pointer - kTlsTcbOffset - TlsPreTcbSize();
294# elif defined(__aarch64__)
295  descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer());
296# elif defined(__powerpc64__)
297  // PPC64LE uses TLS variant I. The thread pointer (in GPR 13)
298  // points to the end of the TCB + 0x7000. The pthread_descr structure is
299  // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
300  // TCB and the size of pthread_descr.
301  const uptr kTlsTcbOffset = 0x7000;
302  uptr thread_pointer;
303  asm("addi %0,13,%1" : "=r"(thread_pointer) : "I"(-kTlsTcbOffset));
304  descr_addr = thread_pointer - TlsPreTcbSize();
305# else
306#  error "unsupported CPU arch"
307# endif
308  return descr_addr;
309}
310#endif  // (x86_64 || i386 || MIPS) && SANITIZER_LINUX
311
312#if SANITIZER_FREEBSD
313static void **ThreadSelfSegbase() {
314  void **segbase = 0;
315# if defined(__i386__)
316  // sysarch(I386_GET_GSBASE, segbase);
317  __asm __volatile("mov %%gs:0, %0" : "=r" (segbase));
318# elif defined(__x86_64__)
319  // sysarch(AMD64_GET_FSBASE, segbase);
320  __asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
321# else
322#  error "unsupported CPU arch for FreeBSD platform"
323# endif
324  return segbase;
325}
326
327uptr ThreadSelf() {
328  return (uptr)ThreadSelfSegbase()[2];
329}
330#endif  // SANITIZER_FREEBSD
331
332#if !SANITIZER_GO
333static void GetTls(uptr *addr, uptr *size) {
334#if SANITIZER_LINUX && !SANITIZER_ANDROID
335# if defined(__x86_64__) || defined(__i386__)
336  *addr = ThreadSelf();
337  *size = GetTlsSize();
338  *addr -= *size;
339  *addr += ThreadDescriptorSize();
340# elif defined(__mips__) || defined(__aarch64__) || defined(__powerpc64__)
341  *addr = ThreadSelf();
342  *size = GetTlsSize();
343# else
344  *addr = 0;
345  *size = 0;
346# endif
347#elif SANITIZER_FREEBSD
348  void** segbase = ThreadSelfSegbase();
349  *addr = 0;
350  *size = 0;
351  if (segbase != 0) {
352    // tcbalign = 16
353    // tls_size = round(tls_static_space, tcbalign);
354    // dtv = segbase[1];
355    // dtv[2] = segbase - tls_static_space;
356    void **dtv = (void**) segbase[1];
357    *addr = (uptr) dtv[2];
358    *size = (*addr == 0) ? 0 : ((uptr) segbase[0] - (uptr) dtv[2]);
359  }
360#elif SANITIZER_ANDROID
361  *addr = 0;
362  *size = 0;
363#else
364# error "Unknown OS"
365#endif
366}
367#endif
368
369#if !SANITIZER_GO
370uptr GetTlsSize() {
371#if SANITIZER_FREEBSD || SANITIZER_ANDROID
372  uptr addr, size;
373  GetTls(&addr, &size);
374  return size;
375#else
376  return g_tls_size;
377#endif
378}
379#endif
380
381void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
382                          uptr *tls_addr, uptr *tls_size) {
383#if SANITIZER_GO
384  // Stub implementation for Go.
385  *stk_addr = *stk_size = *tls_addr = *tls_size = 0;
386#else
387  GetTls(tls_addr, tls_size);
388
389  uptr stack_top, stack_bottom;
390  GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
391  *stk_addr = stack_bottom;
392  *stk_size = stack_top - stack_bottom;
393
394  if (!main) {
395    // If stack and tls intersect, make them non-intersecting.
396    if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
397      CHECK_GT(*tls_addr + *tls_size, *stk_addr);
398      CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
399      *stk_size -= *tls_size;
400      *tls_addr = *stk_addr + *stk_size;
401    }
402  }
403#endif
404}
405
406# if !SANITIZER_FREEBSD
407typedef ElfW(Phdr) Elf_Phdr;
408# elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001  // v9.2
409#  define Elf_Phdr XElf32_Phdr
410#  define dl_phdr_info xdl_phdr_info
411#  define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
412# endif
413
414struct DlIteratePhdrData {
415  LoadedModule *modules;
416  uptr current_n;
417  bool first;
418  uptr max_n;
419  string_predicate_t filter;
420};
421
422static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
423  DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
424  if (data->current_n == data->max_n)
425    return 0;
426  InternalScopedString module_name(kMaxPathLength);
427  if (data->first) {
428    data->first = false;
429    // First module is the binary itself.
430    ReadBinaryNameCached(module_name.data(), module_name.size());
431  } else if (info->dlpi_name) {
432    module_name.append("%s", info->dlpi_name);
433  }
434  if (module_name[0] == '\0')
435    return 0;
436  if (data->filter && !data->filter(module_name.data()))
437    return 0;
438  LoadedModule *cur_module = &data->modules[data->current_n];
439  cur_module->set(module_name.data(), info->dlpi_addr);
440  data->current_n++;
441  for (int i = 0; i < info->dlpi_phnum; i++) {
442    const Elf_Phdr *phdr = &info->dlpi_phdr[i];
443    if (phdr->p_type == PT_LOAD) {
444      uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
445      uptr cur_end = cur_beg + phdr->p_memsz;
446      bool executable = phdr->p_flags & PF_X;
447      cur_module->addAddressRange(cur_beg, cur_end, executable);
448    }
449  }
450  return 0;
451}
452
453#if SANITIZER_ANDROID && __ANDROID_API__ < 21
454extern "C" __attribute__((weak)) int dl_iterate_phdr(
455    int (*)(struct dl_phdr_info *, size_t, void *), void *);
456#endif
457
458uptr GetListOfModules(LoadedModule *modules, uptr max_modules,
459                      string_predicate_t filter) {
460#if SANITIZER_ANDROID && __ANDROID_API__ <= 22
461  u32 api_level = AndroidGetApiLevel();
462  // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
463  // The runtime check allows the same library to work with
464  // both K and L (and future) Android releases.
465  if (api_level <= ANDROID_LOLLIPOP_MR1) { // L or earlier
466    MemoryMappingLayout memory_mapping(false);
467    return memory_mapping.DumpListOfModules(modules, max_modules, filter);
468  }
469#endif
470  CHECK(modules);
471  DlIteratePhdrData data = {modules, 0, true, max_modules, filter};
472  dl_iterate_phdr(dl_iterate_phdr_cb, &data);
473  return data.current_n;
474}
475
476// getrusage does not give us the current RSS, only the max RSS.
477// Still, this is better than nothing if /proc/self/statm is not available
478// for some reason, e.g. due to a sandbox.
479static uptr GetRSSFromGetrusage() {
480  struct rusage usage;
481  if (getrusage(RUSAGE_SELF, &usage))  // Failed, probably due to a sandbox.
482    return 0;
483  return usage.ru_maxrss << 10;  // ru_maxrss is in Kb.
484}
485
486uptr GetRSS() {
487  if (!common_flags()->can_use_proc_maps_statm)
488    return GetRSSFromGetrusage();
489  fd_t fd = OpenFile("/proc/self/statm", RdOnly);
490  if (fd == kInvalidFd)
491    return GetRSSFromGetrusage();
492  char buf[64];
493  uptr len = internal_read(fd, buf, sizeof(buf) - 1);
494  internal_close(fd);
495  if ((sptr)len <= 0)
496    return 0;
497  buf[len] = 0;
498  // The format of the file is:
499  // 1084 89 69 11 0 79 0
500  // We need the second number which is RSS in pages.
501  char *pos = buf;
502  // Skip the first number.
503  while (*pos >= '0' && *pos <= '9')
504    pos++;
505  // Skip whitespaces.
506  while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
507    pos++;
508  // Read the number.
509  uptr rss = 0;
510  while (*pos >= '0' && *pos <= '9')
511    rss = rss * 10 + *pos++ - '0';
512  return rss * GetPageSizeCached();
513}
514
515// 64-bit Android targets don't provide the deprecated __android_log_write.
516// Starting with the L release, syslog() works and is preferable to
517// __android_log_write.
518#if SANITIZER_LINUX
519
520#if SANITIZER_ANDROID
521static atomic_uint8_t android_log_initialized;
522
523void AndroidLogInit() {
524  atomic_store(&android_log_initialized, 1, memory_order_release);
525}
526
527bool ShouldLogAfterPrintf() {
528  return atomic_load(&android_log_initialized, memory_order_acquire);
529}
530#else
531void AndroidLogInit() {}
532
533bool ShouldLogAfterPrintf() { return true; }
534#endif  // SANITIZER_ANDROID
535
536void WriteOneLineToSyslog(const char *s) {
537#if SANITIZER_ANDROID &&__ANDROID_API__ < 21
538  __android_log_write(ANDROID_LOG_INFO, NULL, s);
539#else
540  syslog(LOG_INFO, "%s", s);
541#endif
542}
543
544#endif // SANITIZER_LINUX
545
546} // namespace __sanitizer
547
548#endif // SANITIZER_FREEBSD || SANITIZER_LINUX
549