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