1 //===-- sanitizer_linux_libcdep.cc ----------------------------------------===//
2 //
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
5 //
6 //===----------------------------------------------------------------------===//
7 //
8 // This file is shared between AddressSanitizer and ThreadSanitizer
9 // run-time libraries and implements linux-specific functions from
10 // sanitizer_libc.h.
11 //===----------------------------------------------------------------------===//
12 
13 #include "sanitizer_platform.h"
14 
15 #if SANITIZER_FREEBSD || SANITIZER_LINUX
16 
17 #include "sanitizer_allocator_internal.h"
18 #include "sanitizer_atomic.h"
19 #include "sanitizer_common.h"
20 #include "sanitizer_flags.h"
21 #include "sanitizer_freebsd.h"
22 #include "sanitizer_linux.h"
23 #include "sanitizer_placement_new.h"
24 #include "sanitizer_procmaps.h"
25 #include "sanitizer_stacktrace.h"
26 
27 #if SANITIZER_ANDROID || SANITIZER_FREEBSD
28 #include <dlfcn.h>  // for dlsym()
29 #endif
30 
31 #include <link.h>
32 #include <pthread.h>
33 #include <signal.h>
34 #include <sys/resource.h>
35 
36 #if SANITIZER_FREEBSD
37 #include <pthread_np.h>
38 #include <osreldate.h>
39 #define pthread_getattr_np pthread_attr_get_np
40 #endif
41 
42 #if SANITIZER_LINUX
43 #include <sys/prctl.h>
44 #endif
45 
46 #if SANITIZER_ANDROID
47 #include <android/api-level.h>
48 #endif
49 
50 #if SANITIZER_ANDROID && __ANDROID_API__ < 21
51 #include <android/log.h>
52 #else
53 #include <syslog.h>
54 #endif
55 
56 #if !SANITIZER_ANDROID
57 #include <elf.h>
58 #include <unistd.h>
59 #endif
60 
61 namespace __sanitizer {
62 
63 SANITIZER_WEAK_ATTRIBUTE int
64 real_sigaction(int signum, const void *act, void *oldact);
65 
internal_sigaction(int signum,const void * act,void * oldact)66 int internal_sigaction(int signum, const void *act, void *oldact) {
67 #if !SANITIZER_GO
68   if (&real_sigaction)
69     return real_sigaction(signum, act, oldact);
70 #endif
71   return sigaction(signum, (const struct sigaction *)act,
72                    (struct sigaction *)oldact);
73 }
74 
GetThreadStackTopAndBottom(bool at_initialization,uptr * stack_top,uptr * stack_bottom)75 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
76                                 uptr *stack_bottom) {
77   CHECK(stack_top);
78   CHECK(stack_bottom);
79   if (at_initialization) {
80     // This is the main thread. Libpthread may not be initialized yet.
81     struct rlimit rl;
82     CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
83 
84     // Find the mapping that contains a stack variable.
85     MemoryMappingLayout proc_maps(/*cache_enabled*/true);
86     uptr start, end, offset;
87     uptr prev_end = 0;
88     while (proc_maps.Next(&start, &end, &offset, nullptr, 0,
89           /* protection */nullptr)) {
90       if ((uptr)&rl < end)
91         break;
92       prev_end = end;
93     }
94     CHECK((uptr)&rl >= start && (uptr)&rl < end);
95 
96     // Get stacksize from rlimit, but clip it so that it does not overlap
97     // with other mappings.
98     uptr stacksize = rl.rlim_cur;
99     if (stacksize > end - prev_end)
100       stacksize = end - prev_end;
101     // When running with unlimited stack size, we still want to set some limit.
102     // The unlimited stack size is caused by 'ulimit -s unlimited'.
103     // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
104     if (stacksize > kMaxThreadStackSize)
105       stacksize = kMaxThreadStackSize;
106     *stack_top = end;
107     *stack_bottom = end - stacksize;
108     return;
109   }
110   pthread_attr_t attr;
111   pthread_attr_init(&attr);
112   CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
113   uptr stacksize = 0;
114   void *stackaddr = nullptr;
115   my_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
116   pthread_attr_destroy(&attr);
117 
118   CHECK_LE(stacksize, kMaxThreadStackSize);  // Sanity check.
119   *stack_top = (uptr)stackaddr + stacksize;
120   *stack_bottom = (uptr)stackaddr;
121 }
122 
123 #if !SANITIZER_GO
SetEnv(const char * name,const char * value)124 bool SetEnv(const char *name, const char *value) {
125   void *f = dlsym(RTLD_NEXT, "setenv");
126   if (!f)
127     return false;
128   typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
129   setenv_ft setenv_f;
130   CHECK_EQ(sizeof(setenv_f), sizeof(f));
131   internal_memcpy(&setenv_f, &f, sizeof(f));
132   return setenv_f(name, value, 1) == 0;
133 }
134 #endif
135 
SanitizerSetThreadName(const char * name)136 bool SanitizerSetThreadName(const char *name) {
137 #ifdef PR_SET_NAME
138   return 0 == prctl(PR_SET_NAME, (unsigned long)name, 0, 0, 0);  // NOLINT
139 #else
140   return false;
141 #endif
142 }
143 
SanitizerGetThreadName(char * name,int max_len)144 bool SanitizerGetThreadName(char *name, int max_len) {
145 #ifdef PR_GET_NAME
146   char buff[17];
147   if (prctl(PR_GET_NAME, (unsigned long)buff, 0, 0, 0))  // NOLINT
148     return false;
149   internal_strncpy(name, buff, max_len);
150   name[max_len] = 0;
151   return true;
152 #else
153   return false;
154 #endif
155 }
156 
157 #if !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO
158 static uptr g_tls_size;
159 #endif
160 
161 #ifdef __i386__
162 # define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
163 #else
164 # define DL_INTERNAL_FUNCTION
165 #endif
166 
167 #if defined(__mips__) || defined(__powerpc64__)
168 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb
169 // head structure. It lies before the static tls blocks.
TlsPreTcbSize()170 static uptr TlsPreTcbSize() {
171 # if defined(__mips__)
172   const uptr kTcbHead = 16; // sizeof (tcbhead_t)
173 # elif defined(__powerpc64__)
174   const uptr kTcbHead = 88; // sizeof (tcbhead_t)
175 # endif
176   const uptr kTlsAlign = 16;
177   const uptr kTlsPreTcbSize =
178     (ThreadDescriptorSize() + kTcbHead + kTlsAlign - 1) & ~(kTlsAlign - 1);
179   InitTlsSize();
180   g_tls_size = (g_tls_size + kTlsPreTcbSize + kTlsAlign -1) & ~(kTlsAlign - 1);
181   return kTlsPreTcbSize;
182 }
183 #endif
184 
InitTlsSize()185 void InitTlsSize() {
186 #if !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO
187 // all current supported platforms have 16 bytes stack alignment
188   const size_t kStackAlign = 16;
189   typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
190   get_tls_func get_tls;
191   void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
192   CHECK_EQ(sizeof(get_tls), sizeof(get_tls_static_info_ptr));
193   internal_memcpy(&get_tls, &get_tls_static_info_ptr,
194                   sizeof(get_tls_static_info_ptr));
195   CHECK_NE(get_tls, 0);
196   size_t tls_size = 0;
197   size_t tls_align = 0;
198   get_tls(&tls_size, &tls_align);
199   if (tls_align < kStackAlign)
200     tls_align = kStackAlign;
201   g_tls_size = RoundUpTo(tls_size, tls_align);
202 #endif  // !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO
203 }
204 
205 #if (defined(__x86_64__) || defined(__i386__) || defined(__mips__) \
206     || defined(__aarch64__) || defined(__powerpc64__)) \
207     && SANITIZER_LINUX && !SANITIZER_ANDROID
208 // sizeof(struct pthread) from glibc.
209 static atomic_uintptr_t kThreadDescriptorSize;
210 
ThreadDescriptorSize()211 uptr ThreadDescriptorSize() {
212   uptr val = atomic_load(&kThreadDescriptorSize, memory_order_relaxed);
213   if (val)
214     return val;
215 #if defined(__x86_64__) || defined(__i386__)
216 #ifdef _CS_GNU_LIBC_VERSION
217   char buf[64];
218   uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
219   if (len < sizeof(buf) && internal_strncmp(buf, "glibc 2.", 8) == 0) {
220     char *end;
221     int minor = internal_simple_strtoll(buf + 8, &end, 10);
222     if (end != buf + 8 && (*end == '\0' || *end == '.')) {
223       /* sizeof(struct pthread) values from various glibc versions.  */
224       if (SANITIZER_X32)
225         val = 1728;  // Assume only one particular version for x32.
226       else if (minor <= 3)
227         val = FIRST_32_SECOND_64(1104, 1696);
228       else if (minor == 4)
229         val = FIRST_32_SECOND_64(1120, 1728);
230       else if (minor == 5)
231         val = FIRST_32_SECOND_64(1136, 1728);
232       else if (minor <= 9)
233         val = FIRST_32_SECOND_64(1136, 1712);
234       else if (minor == 10)
235         val = FIRST_32_SECOND_64(1168, 1776);
236       else if (minor <= 12)
237         val = FIRST_32_SECOND_64(1168, 2288);
238       else if (minor == 13)
239         val = FIRST_32_SECOND_64(1168, 2304);
240       else
241         val = FIRST_32_SECOND_64(1216, 2304);
242     }
243     if (val)
244       atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
245     return val;
246   }
247 #endif
248 #elif defined(__mips__)
249   // TODO(sagarthakur): add more values as per different glibc versions.
250   val = FIRST_32_SECOND_64(1152, 1776);
251   if (val)
252     atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
253   return val;
254 #elif defined(__aarch64__)
255   // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
256   val = 1776;
257   atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
258   return val;
259 #elif defined(__powerpc64__)
260   val = 1776; // from glibc.ppc64le 2.20-8.fc21
261   atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
262   return val;
263 #endif
264   return 0;
265 }
266 
267 // The offset at which pointer to self is located in the thread descriptor.
268 const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
269 
ThreadSelfOffset()270 uptr ThreadSelfOffset() {
271   return kThreadSelfOffset;
272 }
273 
ThreadSelf()274 uptr ThreadSelf() {
275   uptr descr_addr;
276 # if defined(__i386__)
277   asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
278 # elif defined(__x86_64__)
279   asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
280 # elif defined(__mips__)
281   // MIPS uses TLS variant I. The thread pointer (in hardware register $29)
282   // points to the end of the TCB + 0x7000. The pthread_descr structure is
283   // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
284   // TCB and the size of pthread_descr.
285   const uptr kTlsTcbOffset = 0x7000;
286   uptr thread_pointer;
287   asm volatile(".set push;\
288                 .set mips64r2;\
289                 rdhwr %0,$29;\
290                 .set pop" : "=r" (thread_pointer));
291   descr_addr = thread_pointer - kTlsTcbOffset - TlsPreTcbSize();
292 # elif defined(__aarch64__)
293   descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer());
294 # elif defined(__powerpc64__)
295   // PPC64LE uses TLS variant I. The thread pointer (in GPR 13)
296   // points to the end of the TCB + 0x7000. The pthread_descr structure is
297   // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
298   // TCB and the size of pthread_descr.
299   const uptr kTlsTcbOffset = 0x7000;
300   uptr thread_pointer;
301   asm("addi %0,13,%1" : "=r"(thread_pointer) : "I"(-kTlsTcbOffset));
302   descr_addr = thread_pointer - TlsPreTcbSize();
303 # else
304 #  error "unsupported CPU arch"
305 # endif
306   return descr_addr;
307 }
308 #endif  // (x86_64 || i386 || MIPS) && SANITIZER_LINUX
309 
310 #if SANITIZER_FREEBSD
ThreadSelfSegbase()311 static void **ThreadSelfSegbase() {
312   void **segbase = 0;
313 # if defined(__i386__)
314   // sysarch(I386_GET_GSBASE, segbase);
315   __asm __volatile("mov %%gs:0, %0" : "=r" (segbase));
316 # elif defined(__x86_64__)
317   // sysarch(AMD64_GET_FSBASE, segbase);
318   __asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
319 # else
320 #  error "unsupported CPU arch for FreeBSD platform"
321 # endif
322   return segbase;
323 }
324 
ThreadSelf()325 uptr ThreadSelf() {
326   return (uptr)ThreadSelfSegbase()[2];
327 }
328 #endif  // SANITIZER_FREEBSD
329 
330 #if !SANITIZER_GO
GetTls(uptr * addr,uptr * size)331 static void GetTls(uptr *addr, uptr *size) {
332 #if SANITIZER_LINUX && !SANITIZER_ANDROID
333 # if defined(__x86_64__) || defined(__i386__)
334   *addr = ThreadSelf();
335   *size = GetTlsSize();
336   *addr -= *size;
337   *addr += ThreadDescriptorSize();
338 # elif defined(__mips__) || defined(__aarch64__) || defined(__powerpc64__)
339   *addr = ThreadSelf();
340   *size = GetTlsSize();
341 # else
342   *addr = 0;
343   *size = 0;
344 # endif
345 #elif SANITIZER_FREEBSD
346   void** segbase = ThreadSelfSegbase();
347   *addr = 0;
348   *size = 0;
349   if (segbase != 0) {
350     // tcbalign = 16
351     // tls_size = round(tls_static_space, tcbalign);
352     // dtv = segbase[1];
353     // dtv[2] = segbase - tls_static_space;
354     void **dtv = (void**) segbase[1];
355     *addr = (uptr) dtv[2];
356     *size = (*addr == 0) ? 0 : ((uptr) segbase[0] - (uptr) dtv[2]);
357   }
358 #elif SANITIZER_ANDROID
359   *addr = 0;
360   *size = 0;
361 #else
362 # error "Unknown OS"
363 #endif
364 }
365 #endif
366 
367 #if !SANITIZER_GO
GetTlsSize()368 uptr GetTlsSize() {
369 #if SANITIZER_FREEBSD || SANITIZER_ANDROID
370   uptr addr, size;
371   GetTls(&addr, &size);
372   return size;
373 #else
374   return g_tls_size;
375 #endif
376 }
377 #endif
378 
GetThreadStackAndTls(bool main,uptr * stk_addr,uptr * stk_size,uptr * tls_addr,uptr * tls_size)379 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
380                           uptr *tls_addr, uptr *tls_size) {
381 #if SANITIZER_GO
382   // Stub implementation for Go.
383   *stk_addr = *stk_size = *tls_addr = *tls_size = 0;
384 #else
385   GetTls(tls_addr, tls_size);
386 
387   uptr stack_top, stack_bottom;
388   GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
389   *stk_addr = stack_bottom;
390   *stk_size = stack_top - stack_bottom;
391 
392   if (!main) {
393     // If stack and tls intersect, make them non-intersecting.
394     if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
395       CHECK_GT(*tls_addr + *tls_size, *stk_addr);
396       CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
397       *stk_size -= *tls_size;
398       *tls_addr = *stk_addr + *stk_size;
399     }
400   }
401 #endif
402 }
403 
404 # if !SANITIZER_FREEBSD
405 typedef ElfW(Phdr) Elf_Phdr;
406 # elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001  // v9.2
407 #  define Elf_Phdr XElf32_Phdr
408 #  define dl_phdr_info xdl_phdr_info
409 #  define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
410 # endif
411 
412 struct DlIteratePhdrData {
413   LoadedModule *modules;
414   uptr current_n;
415   bool first;
416   uptr max_n;
417   string_predicate_t filter;
418 };
419 
dl_iterate_phdr_cb(dl_phdr_info * info,size_t size,void * arg)420 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
421   DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
422   if (data->current_n == data->max_n)
423     return 0;
424   InternalScopedString module_name(kMaxPathLength);
425   if (data->first) {
426     data->first = false;
427     // First module is the binary itself.
428     ReadBinaryNameCached(module_name.data(), module_name.size());
429   } else if (info->dlpi_name) {
430     module_name.append("%s", info->dlpi_name);
431   }
432   if (module_name[0] == '\0')
433     return 0;
434   if (data->filter && !data->filter(module_name.data()))
435     return 0;
436   LoadedModule *cur_module = &data->modules[data->current_n];
437   cur_module->set(module_name.data(), info->dlpi_addr);
438   data->current_n++;
439   for (int i = 0; i < info->dlpi_phnum; i++) {
440     const Elf_Phdr *phdr = &info->dlpi_phdr[i];
441     if (phdr->p_type == PT_LOAD) {
442       uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
443       uptr cur_end = cur_beg + phdr->p_memsz;
444       bool executable = phdr->p_flags & PF_X;
445       cur_module->addAddressRange(cur_beg, cur_end, executable);
446     }
447   }
448   return 0;
449 }
450 
451 #if SANITIZER_ANDROID && __ANDROID_API__ < 21
452 extern "C" __attribute__((weak)) int dl_iterate_phdr(
453     int (*)(struct dl_phdr_info *, size_t, void *), void *);
454 #endif
455 
GetListOfModules(LoadedModule * modules,uptr max_modules,string_predicate_t filter)456 uptr GetListOfModules(LoadedModule *modules, uptr max_modules,
457                       string_predicate_t filter) {
458 #if SANITIZER_ANDROID && __ANDROID_API__ <= 22
459   u32 api_level = AndroidGetApiLevel();
460   // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
461   // The runtime check allows the same library to work with
462   // both K and L (and future) Android releases.
463   if (api_level <= ANDROID_LOLLIPOP_MR1) { // L or earlier
464     MemoryMappingLayout memory_mapping(false);
465     return memory_mapping.DumpListOfModules(modules, max_modules, filter);
466   }
467 #endif
468   CHECK(modules);
469   DlIteratePhdrData data = {modules, 0, true, max_modules, filter};
470   dl_iterate_phdr(dl_iterate_phdr_cb, &data);
471   return data.current_n;
472 }
473 
474 // getrusage does not give us the current RSS, only the max RSS.
475 // Still, this is better than nothing if /proc/self/statm is not available
476 // for some reason, e.g. due to a sandbox.
GetRSSFromGetrusage()477 static uptr GetRSSFromGetrusage() {
478   struct rusage usage;
479   if (getrusage(RUSAGE_SELF, &usage))  // Failed, probably due to a sandbox.
480     return 0;
481   return usage.ru_maxrss << 10;  // ru_maxrss is in Kb.
482 }
483 
GetRSS()484 uptr GetRSS() {
485   if (!common_flags()->can_use_proc_maps_statm)
486     return GetRSSFromGetrusage();
487   fd_t fd = OpenFile("/proc/self/statm", RdOnly);
488   if (fd == kInvalidFd)
489     return GetRSSFromGetrusage();
490   char buf[64];
491   uptr len = internal_read(fd, buf, sizeof(buf) - 1);
492   internal_close(fd);
493   if ((sptr)len <= 0)
494     return 0;
495   buf[len] = 0;
496   // The format of the file is:
497   // 1084 89 69 11 0 79 0
498   // We need the second number which is RSS in pages.
499   char *pos = buf;
500   // Skip the first number.
501   while (*pos >= '0' && *pos <= '9')
502     pos++;
503   // Skip whitespaces.
504   while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
505     pos++;
506   // Read the number.
507   uptr rss = 0;
508   while (*pos >= '0' && *pos <= '9')
509     rss = rss * 10 + *pos++ - '0';
510   return rss * GetPageSizeCached();
511 }
512 
513 // 64-bit Android targets don't provide the deprecated __android_log_write.
514 // Starting with the L release, syslog() works and is preferable to
515 // __android_log_write.
516 #if SANITIZER_LINUX
517 
518 #if SANITIZER_ANDROID
519 static atomic_uint8_t android_log_initialized;
520 
AndroidLogInit()521 void AndroidLogInit() {
522   atomic_store(&android_log_initialized, 1, memory_order_release);
523 }
524 
IsSyslogAvailable()525 static bool IsSyslogAvailable() {
526   return atomic_load(&android_log_initialized, memory_order_acquire);
527 }
528 #else
AndroidLogInit()529 void AndroidLogInit() {}
530 
IsSyslogAvailable()531 static bool IsSyslogAvailable() { return true; }
532 #endif  // SANITIZER_ANDROID
533 
WriteOneLineToSyslog(const char * s)534 static void WriteOneLineToSyslog(const char *s) {
535 #if SANITIZER_ANDROID &&__ANDROID_API__ < 21
536   __android_log_write(ANDROID_LOG_INFO, NULL, s);
537 #else
538   syslog(LOG_INFO, "%s", s);
539 #endif
540 }
541 
WriteToSyslog(const char * buffer)542 void WriteToSyslog(const char *buffer) {
543   if (!IsSyslogAvailable())
544     return;
545   char *copy = internal_strdup(buffer);
546   char *p = copy;
547   char *q;
548   // syslog, at least on Android, has an implicit message length limit.
549   // Print one line at a time.
550   do {
551     q = internal_strchr(p, '\n');
552     if (q)
553       *q = '\0';
554     WriteOneLineToSyslog(p);
555     if (q)
556       p = q + 1;
557   } while (q);
558   InternalFree(copy);
559 }
560 #endif // SANITIZER_LINUX
561 
562 } // namespace __sanitizer
563 
564 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX
565