sanitizer_linux_libcdep.cc revision 088ea2b46f97172bd0b0663a629e11cf826b84f7 
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#if SANITIZER_LINUX
17
18#include "sanitizer_common.h"
19#include "sanitizer_procmaps.h"
20#include "sanitizer_stacktrace.h"
21
22#ifdef __x86_64__
23#include <asm/prctl.h>
24#endif
25#include <dlfcn.h>
26#include <pthread.h>
27#include <sys/prctl.h>
28#include <sys/resource.h>
29#include <unwind.h>
30
31#ifdef __x86_64__
32extern "C" int arch_prctl(int code, __sanitizer::uptr *addr);
33#endif
34
35namespace __sanitizer {
36
37void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
38                                uptr *stack_bottom) {
39  static const uptr kMaxThreadStackSize = 256 * (1 << 20);  // 256M
40  CHECK(stack_top);
41  CHECK(stack_bottom);
42  if (at_initialization) {
43    // This is the main thread. Libpthread may not be initialized yet.
44    struct rlimit rl;
45    CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
46
47    // Find the mapping that contains a stack variable.
48    MemoryMappingLayout proc_maps(/*cache_enabled*/true);
49    uptr start, end, offset;
50    uptr prev_end = 0;
51    while (proc_maps.Next(&start, &end, &offset, 0, 0, /* protection */0)) {
52      if ((uptr)&rl < end)
53        break;
54      prev_end = end;
55    }
56    CHECK((uptr)&rl >= start && (uptr)&rl < end);
57
58    // Get stacksize from rlimit, but clip it so that it does not overlap
59    // with other mappings.
60    uptr stacksize = rl.rlim_cur;
61    if (stacksize > end - prev_end)
62      stacksize = end - prev_end;
63    // When running with unlimited stack size, we still want to set some limit.
64    // The unlimited stack size is caused by 'ulimit -s unlimited'.
65    // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
66    if (stacksize > kMaxThreadStackSize)
67      stacksize = kMaxThreadStackSize;
68    *stack_top = end;
69    *stack_bottom = end - stacksize;
70    return;
71  }
72  pthread_attr_t attr;
73  CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
74  uptr stacksize = 0;
75  void *stackaddr = 0;
76  pthread_attr_getstack(&attr, &stackaddr, (size_t*)&stacksize);
77  pthread_attr_destroy(&attr);
78
79  *stack_top = (uptr)stackaddr + stacksize;
80  *stack_bottom = (uptr)stackaddr;
81  CHECK(stacksize < kMaxThreadStackSize);  // Sanity check.
82}
83
84// Does not compile for Go because dlsym() requires -ldl
85#ifndef SANITIZER_GO
86bool SetEnv(const char *name, const char *value) {
87  void *f = dlsym(RTLD_NEXT, "setenv");
88  if (f == 0)
89    return false;
90  typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
91  setenv_ft setenv_f;
92  CHECK_EQ(sizeof(setenv_f), sizeof(f));
93  internal_memcpy(&setenv_f, &f, sizeof(f));
94  return setenv_f(name, value, 1) == 0;
95}
96#endif
97
98bool SanitizerSetThreadName(const char *name) {
99#ifdef PR_SET_NAME
100  return 0 == prctl(PR_SET_NAME, (unsigned long)name, 0, 0, 0);  // NOLINT
101#else
102  return false;
103#endif
104}
105
106bool SanitizerGetThreadName(char *name, int max_len) {
107#ifdef PR_GET_NAME
108  char buff[17];
109  if (prctl(PR_GET_NAME, (unsigned long)buff, 0, 0, 0))  // NOLINT
110    return false;
111  internal_strncpy(name, buff, max_len);
112  name[max_len] = 0;
113  return true;
114#else
115  return false;
116#endif
117}
118
119#ifndef SANITIZER_GO
120//------------------------- SlowUnwindStack -----------------------------------
121#ifdef __arm__
122#define UNWIND_STOP _URC_END_OF_STACK
123#define UNWIND_CONTINUE _URC_NO_REASON
124#else
125#define UNWIND_STOP _URC_NORMAL_STOP
126#define UNWIND_CONTINUE _URC_NO_REASON
127#endif
128
129uptr Unwind_GetIP(struct _Unwind_Context *ctx) {
130#ifdef __arm__
131  uptr val;
132  _Unwind_VRS_Result res = _Unwind_VRS_Get(ctx, _UVRSC_CORE,
133      15 /* r15 = PC */, _UVRSD_UINT32, &val);
134  CHECK(res == _UVRSR_OK && "_Unwind_VRS_Get failed");
135  // Clear the Thumb bit.
136  return val & ~(uptr)1;
137#else
138  return _Unwind_GetIP(ctx);
139#endif
140}
141
142_Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx, void *param) {
143  StackTrace *b = (StackTrace*)param;
144  CHECK(b->size < b->max_size);
145  uptr pc = Unwind_GetIP(ctx);
146  b->trace[b->size++] = pc;
147  if (b->size == b->max_size) return UNWIND_STOP;
148  return UNWIND_CONTINUE;
149}
150
151static bool MatchPc(uptr cur_pc, uptr trace_pc) {
152  return cur_pc - trace_pc <= 64 || trace_pc - cur_pc <= 64;
153}
154
155void StackTrace::SlowUnwindStack(uptr pc, uptr max_depth) {
156  this->size = 0;
157  this->max_size = max_depth;
158  if (max_depth > 1) {
159    _Unwind_Backtrace(Unwind_Trace, this);
160    // We need to pop a few frames so that pc is on top.
161    // trace[0] belongs to the current function so we always pop it.
162    int to_pop = 1;
163    /**/ if (size > 1 && MatchPc(pc, trace[1])) to_pop = 1;
164    else if (size > 2 && MatchPc(pc, trace[2])) to_pop = 2;
165    else if (size > 3 && MatchPc(pc, trace[3])) to_pop = 3;
166    else if (size > 4 && MatchPc(pc, trace[4])) to_pop = 4;
167    else if (size > 5 && MatchPc(pc, trace[5])) to_pop = 5;
168    this->PopStackFrames(to_pop);
169  }
170  this->trace[0] = pc;
171}
172
173#endif  // !SANITIZER_GO
174
175static uptr g_tls_size;
176
177#ifdef __i386__
178# define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
179#else
180# define DL_INTERNAL_FUNCTION
181#endif
182
183void InitTlsSize() {
184#if !defined(SANITIZER_GO) && !SANITIZER_ANDROID
185  typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
186  get_tls_func get_tls;
187  void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
188  CHECK_EQ(sizeof(get_tls), sizeof(get_tls_static_info_ptr));
189  internal_memcpy(&get_tls, &get_tls_static_info_ptr,
190                  sizeof(get_tls_static_info_ptr));
191  CHECK_NE(get_tls, 0);
192  size_t tls_size = 0;
193  size_t tls_align = 0;
194  get_tls(&tls_size, &tls_align);
195  g_tls_size = tls_size;
196#endif
197}
198
199uptr GetTlsSize() {
200  return g_tls_size;
201}
202
203// sizeof(struct thread) from glibc.
204#ifdef __x86_64__
205const uptr kThreadDescriptorSize = 2304;
206
207uptr ThreadDescriptorSize() {
208  return kThreadDescriptorSize;
209}
210#endif
211
212void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
213                          uptr *tls_addr, uptr *tls_size) {
214#ifndef SANITIZER_GO
215#ifdef __x86_64__
216  arch_prctl(ARCH_GET_FS, tls_addr);
217  *tls_size = GetTlsSize();
218  *tls_addr -= *tls_size;
219  *tls_addr += kThreadDescriptorSize;
220#else
221  *tls_addr = 0;
222  *tls_size = 0;
223#endif
224
225  uptr stack_top, stack_bottom;
226  GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
227  *stk_addr = stack_bottom;
228  *stk_size = stack_top - stack_bottom;
229
230  if (!main) {
231    // If stack and tls intersect, make them non-intersecting.
232    if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
233      CHECK_GT(*tls_addr + *tls_size, *stk_addr);
234      CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
235      *stk_size -= *tls_size;
236      *tls_addr = *stk_addr + *stk_size;
237    }
238  }
239#else  // SANITIZER_GO
240  *stk_addr = 0;
241  *stk_size = 0;
242  *tls_addr = 0;
243  *tls_size = 0;
244#endif  // SANITIZER_GO
245}
246
247void AdjustStackSizeLinux(void *attr_, int verbosity) {
248  pthread_attr_t *attr = (pthread_attr_t *)attr_;
249  uptr stackaddr = 0;
250  size_t stacksize = 0;
251  pthread_attr_getstack(attr, (void**)&stackaddr, &stacksize);
252  // GLibC will return (0 - stacksize) as the stack address in the case when
253  // stacksize is set, but stackaddr is not.
254  bool stack_set = (stackaddr != 0) && (stackaddr + stacksize != 0);
255  // We place a lot of tool data into TLS, account for that.
256  const uptr minstacksize = GetTlsSize() + 128*1024;
257  if (stacksize < minstacksize) {
258    if (!stack_set) {
259      if (verbosity && stacksize != 0)
260        Printf("Sanitizer: increasing stacksize %zu->%zu\n", stacksize,
261               minstacksize);
262      pthread_attr_setstacksize(attr, minstacksize);
263    } else {
264      Printf("Sanitizer: pre-allocated stack size is insufficient: "
265             "%zu < %zu\n", stacksize, minstacksize);
266      Printf("Sanitizer: pthread_create is likely to fail.\n");
267    }
268  }
269}
270
271}  // namespace __sanitizer
272
273#endif  // SANITIZER_LINUX
274