asan_linux.cc revision 3dbeabb3446f203156ae03d957de9bdf50933ae4 
1//===-- asan_linux.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 a part of AddressSanitizer, an address sanity checker.
11//
12// Linux-specific details.
13//===----------------------------------------------------------------------===//
14#ifdef __linux__
15
16#include "asan_interceptors.h"
17#include "asan_internal.h"
18#include "asan_lock.h"
19#include "asan_thread.h"
20#include "sanitizer_common/sanitizer_libc.h"
21#include "sanitizer_common/sanitizer_procmaps.h"
22
23#include <sys/time.h>
24#include <sys/resource.h>
25#include <sys/mman.h>
26#include <sys/syscall.h>
27#include <sys/types.h>
28#include <fcntl.h>
29#include <pthread.h>
30#include <stdio.h>
31#include <unistd.h>
32#include <unwind.h>
33
34#ifndef ANDROID
35// FIXME: where to get ucontext on Android?
36#include <sys/ucontext.h>
37#endif
38
39extern "C" void* _DYNAMIC;
40
41namespace __asan {
42
43void *AsanDoesNotSupportStaticLinkage() {
44  // This will fail to link with -static.
45  return &_DYNAMIC;  // defined in link.h
46}
47
48void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
49#ifdef ANDROID
50  *pc = *sp = *bp = 0;
51#elif defined(__arm__)
52  ucontext_t *ucontext = (ucontext_t*)context;
53  *pc = ucontext->uc_mcontext.arm_pc;
54  *bp = ucontext->uc_mcontext.arm_fp;
55  *sp = ucontext->uc_mcontext.arm_sp;
56# elif defined(__x86_64__)
57  ucontext_t *ucontext = (ucontext_t*)context;
58  *pc = ucontext->uc_mcontext.gregs[REG_RIP];
59  *bp = ucontext->uc_mcontext.gregs[REG_RBP];
60  *sp = ucontext->uc_mcontext.gregs[REG_RSP];
61# elif defined(__i386__)
62  ucontext_t *ucontext = (ucontext_t*)context;
63  *pc = ucontext->uc_mcontext.gregs[REG_EIP];
64  *bp = ucontext->uc_mcontext.gregs[REG_EBP];
65  *sp = ucontext->uc_mcontext.gregs[REG_ESP];
66#else
67# error "Unsupported arch"
68#endif
69}
70
71bool AsanInterceptsSignal(int signum) {
72  return signum == SIGSEGV && FLAG_handle_segv;
73}
74
75void *AsanMmapFixedNoReserve(uptr fixed_addr, uptr size) {
76  return internal_mmap((void*)fixed_addr, size,
77                      PROT_READ | PROT_WRITE,
78                      MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
79                      0, 0);
80}
81
82void *AsanMprotect(uptr fixed_addr, uptr size) {
83  return internal_mmap((void*)fixed_addr, size,
84                       PROT_NONE,
85                       MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE,
86                       0, 0);
87}
88
89AsanLock::AsanLock(LinkerInitialized) {
90  // We assume that pthread_mutex_t initialized to all zeroes is a valid
91  // unlocked mutex. We can not use PTHREAD_MUTEX_INITIALIZER as it triggers
92  // a gcc warning:
93  // extended initializer lists only available with -std=c++0x or -std=gnu++0x
94}
95
96void AsanLock::Lock() {
97  CHECK(sizeof(pthread_mutex_t) <= sizeof(opaque_storage_));
98  pthread_mutex_lock((pthread_mutex_t*)&opaque_storage_);
99  CHECK(!owner_);
100  owner_ = (uptr)pthread_self();
101}
102
103void AsanLock::Unlock() {
104  CHECK(owner_ == (uptr)pthread_self());
105  owner_ = 0;
106  pthread_mutex_unlock((pthread_mutex_t*)&opaque_storage_);
107}
108
109#ifdef __arm__
110#define UNWIND_STOP _URC_END_OF_STACK
111#define UNWIND_CONTINUE _URC_NO_REASON
112#else
113#define UNWIND_STOP _URC_NORMAL_STOP
114#define UNWIND_CONTINUE _URC_NO_REASON
115#endif
116
117uptr Unwind_GetIP(struct _Unwind_Context *ctx) {
118#ifdef __arm__
119  uptr val;
120  _Unwind_VRS_Result res = _Unwind_VRS_Get(ctx, _UVRSC_CORE,
121      15 /* r15 = PC */, _UVRSD_UINT32, &val);
122  CHECK(res == _UVRSR_OK && "_Unwind_VRS_Get failed");
123  // Clear the Thumb bit.
124  return val & ~(uptr)1;
125#else
126  return _Unwind_GetIP(ctx);
127#endif
128}
129
130_Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx,
131    void *param) {
132  AsanStackTrace *b = (AsanStackTrace*)param;
133  CHECK(b->size < b->max_size);
134  uptr pc = Unwind_GetIP(ctx);
135  b->trace[b->size++] = pc;
136  if (b->size == b->max_size) return UNWIND_STOP;
137  return UNWIND_CONTINUE;
138}
139
140void AsanStackTrace::GetStackTrace(uptr max_s, uptr pc, uptr bp) {
141  size = 0;
142  trace[0] = pc;
143  if ((max_s) > 1) {
144    max_size = max_s;
145#ifdef __arm__
146    _Unwind_Backtrace(Unwind_Trace, this);
147#else
148     FastUnwindStack(pc, bp);
149#endif
150  }
151}
152
153}  // namespace __asan
154
155#endif  // __linux__
156