asan_linux.cc revision 2b939c3abc8b7713ef28000bd768ca6d77445f45 
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 "asan_thread_registry.h"
21#include "sanitizer_common/sanitizer_libc.h"
22#include "sanitizer_common/sanitizer_procmaps.h"
23
24#include <sys/time.h>
25#include <sys/resource.h>
26#include <sys/mman.h>
27#include <sys/syscall.h>
28#include <sys/types.h>
29#include <fcntl.h>
30#include <pthread.h>
31#include <stdio.h>
32#include <unistd.h>
33#include <unwind.h>
34
35#if !ASAN_ANDROID
36// FIXME: where to get ucontext on Android?
37#include <sys/ucontext.h>
38#endif
39
40extern "C" void* _DYNAMIC;
41
42namespace __asan {
43
44void MaybeReexec() {
45  // No need to re-exec on Linux.
46}
47
48void *AsanDoesNotSupportStaticLinkage() {
49  // This will fail to link with -static.
50  return &_DYNAMIC;  // defined in link.h
51}
52
53void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) {
54#if ASAN_ANDROID
55  *pc = *sp = *bp = 0;
56#elif defined(__arm__)
57  ucontext_t *ucontext = (ucontext_t*)context;
58  *pc = ucontext->uc_mcontext.arm_pc;
59  *bp = ucontext->uc_mcontext.arm_fp;
60  *sp = ucontext->uc_mcontext.arm_sp;
61# elif defined(__x86_64__)
62  ucontext_t *ucontext = (ucontext_t*)context;
63  *pc = ucontext->uc_mcontext.gregs[REG_RIP];
64  *bp = ucontext->uc_mcontext.gregs[REG_RBP];
65  *sp = ucontext->uc_mcontext.gregs[REG_RSP];
66# elif defined(__i386__)
67  ucontext_t *ucontext = (ucontext_t*)context;
68  *pc = ucontext->uc_mcontext.gregs[REG_EIP];
69  *bp = ucontext->uc_mcontext.gregs[REG_EBP];
70  *sp = ucontext->uc_mcontext.gregs[REG_ESP];
71#else
72# error "Unsupported arch"
73#endif
74}
75
76bool AsanInterceptsSignal(int signum) {
77  return signum == SIGSEGV && flags()->handle_segv;
78}
79
80void AsanPlatformThreadInit() {
81  // Nothing here for now.
82}
83
84AsanLock::AsanLock(LinkerInitialized) {
85  // We assume that pthread_mutex_t initialized to all zeroes is a valid
86  // unlocked mutex. We can not use PTHREAD_MUTEX_INITIALIZER as it triggers
87  // a gcc warning:
88  // extended initializer lists only available with -std=c++0x or -std=gnu++0x
89}
90
91void AsanLock::Lock() {
92  CHECK(sizeof(pthread_mutex_t) <= sizeof(opaque_storage_));
93  pthread_mutex_lock((pthread_mutex_t*)&opaque_storage_);
94  CHECK(!owner_);
95  owner_ = (uptr)pthread_self();
96}
97
98void AsanLock::Unlock() {
99  CHECK(owner_ == (uptr)pthread_self());
100  owner_ = 0;
101  pthread_mutex_unlock((pthread_mutex_t*)&opaque_storage_);
102}
103
104#ifdef __arm__
105#define UNWIND_STOP _URC_END_OF_STACK
106#define UNWIND_CONTINUE _URC_NO_REASON
107#else
108#define UNWIND_STOP _URC_NORMAL_STOP
109#define UNWIND_CONTINUE _URC_NO_REASON
110#endif
111
112uptr Unwind_GetIP(struct _Unwind_Context *ctx) {
113#ifdef __arm__
114  uptr val;
115  _Unwind_VRS_Result res = _Unwind_VRS_Get(ctx, _UVRSC_CORE,
116      15 /* r15 = PC */, _UVRSD_UINT32, &val);
117  CHECK(res == _UVRSR_OK && "_Unwind_VRS_Get failed");
118  // Clear the Thumb bit.
119  return val & ~(uptr)1;
120#else
121  return _Unwind_GetIP(ctx);
122#endif
123}
124
125_Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx,
126    void *param) {
127  StackTrace *b = (StackTrace*)param;
128  CHECK(b->size < b->max_size);
129  uptr pc = Unwind_GetIP(ctx);
130  b->trace[b->size++] = pc;
131  if (b->size == b->max_size) return UNWIND_STOP;
132  return UNWIND_CONTINUE;
133}
134
135void GetStackTrace(StackTrace *stack, uptr max_s, uptr pc, uptr bp) {
136  stack->size = 0;
137  stack->trace[0] = pc;
138  if ((max_s) > 1) {
139    stack->max_size = max_s;
140#ifdef __arm__
141    _Unwind_Backtrace(Unwind_Trace, stack);
142#else
143    if (!asan_inited) return;
144    if (AsanThread *t = asanThreadRegistry().GetCurrent())
145      stack->FastUnwindStack(pc, bp, t->stack_top(), t->stack_bottom());
146#endif
147  }
148}
149
150}  // namespace __asan
151
152#endif  // __linux__
153