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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 
     18 #ifndef ART_RUNTIME_FAULT_HANDLER_H_
     19 #define ART_RUNTIME_FAULT_HANDLER_H_
     20 
     21 #include <signal.h>
     22 #include <vector>
     23 #include <setjmp.h>
     24 #include <stdint.h>
     25 
     26 #include "base/mutex.h"   // For annotalysis.
     27 
     28 namespace art {
     29 
     30 class ArtMethod;
     31 class FaultHandler;
     32 
     33 class FaultManager {
     34  public:
     35   FaultManager();
     36   ~FaultManager();
     37 
     38   void Init();
     39 
     40   // Unclaim signals.
     41   void Release();
     42 
     43   // Unclaim signals and delete registered handlers.
     44   void Shutdown();
     45 
     46   // Try to handle a fault, returns true if successful.
     47   bool HandleFault(int sig, siginfo_t* info, void* context);
     48 
     49   // Added handlers are owned by the fault handler and will be freed on Shutdown().
     50   void AddHandler(FaultHandler* handler, bool generated_code);
     51   void RemoveHandler(FaultHandler* handler);
     52 
     53   // Note that the following two functions are called in the context of a signal handler.
     54   // The IsInGeneratedCode() function checks that the mutator lock is held before it
     55   // calls GetMethodAndReturnPCAndSP().
     56   // TODO: think about adding lock assertions and fake lock and unlock functions.
     57   void GetMethodAndReturnPcAndSp(siginfo_t* siginfo, void* context, ArtMethod** out_method,
     58                                  uintptr_t* out_return_pc, uintptr_t* out_sp)
     59                                  NO_THREAD_SAFETY_ANALYSIS;
     60   bool IsInGeneratedCode(siginfo_t* siginfo, void *context, bool check_dex_pc)
     61                          NO_THREAD_SAFETY_ANALYSIS;
     62 
     63  private:
     64   // The HandleFaultByOtherHandlers function is only called by HandleFault function for generated code.
     65   bool HandleFaultByOtherHandlers(int sig, siginfo_t* info, void* context)
     66                                   NO_THREAD_SAFETY_ANALYSIS;
     67 
     68   std::vector<FaultHandler*> generated_code_handlers_;
     69   std::vector<FaultHandler*> other_handlers_;
     70   struct sigaction oldaction_;
     71   bool initialized_;
     72   DISALLOW_COPY_AND_ASSIGN(FaultManager);
     73 };
     74 
     75 class FaultHandler {
     76  public:
     77   explicit FaultHandler(FaultManager* manager);
     78   virtual ~FaultHandler() {}
     79   FaultManager* GetFaultManager() {
     80     return manager_;
     81   }
     82 
     83   virtual bool Action(int sig, siginfo_t* siginfo, void* context) = 0;
     84 
     85  protected:
     86   FaultManager* const manager_;
     87 
     88  private:
     89   DISALLOW_COPY_AND_ASSIGN(FaultHandler);
     90 };
     91 
     92 class NullPointerHandler FINAL : public FaultHandler {
     93  public:
     94   explicit NullPointerHandler(FaultManager* manager);
     95 
     96   bool Action(int sig, siginfo_t* siginfo, void* context) OVERRIDE;
     97 
     98   static bool IsValidImplicitCheck(siginfo_t* siginfo) {
     99     // Our implicit NPE checks always limit the range to a page.
    100     // Note that the runtime will do more exhaustive checks (that we cannot
    101     // reasonably do in signal processing code) based on the dex instruction
    102     // faulting.
    103     return CanDoImplicitNullCheckOn(reinterpret_cast<uintptr_t>(siginfo->si_addr));
    104   }
    105 
    106  private:
    107   DISALLOW_COPY_AND_ASSIGN(NullPointerHandler);
    108 };
    109 
    110 class SuspensionHandler FINAL : public FaultHandler {
    111  public:
    112   explicit SuspensionHandler(FaultManager* manager);
    113 
    114   bool Action(int sig, siginfo_t* siginfo, void* context) OVERRIDE;
    115 
    116  private:
    117   DISALLOW_COPY_AND_ASSIGN(SuspensionHandler);
    118 };
    119 
    120 class StackOverflowHandler FINAL : public FaultHandler {
    121  public:
    122   explicit StackOverflowHandler(FaultManager* manager);
    123 
    124   bool Action(int sig, siginfo_t* siginfo, void* context) OVERRIDE;
    125 
    126  private:
    127   DISALLOW_COPY_AND_ASSIGN(StackOverflowHandler);
    128 };
    129 
    130 class JavaStackTraceHandler FINAL : public FaultHandler {
    131  public:
    132   explicit JavaStackTraceHandler(FaultManager* manager);
    133 
    134   bool Action(int sig, siginfo_t* siginfo, void* context) OVERRIDE NO_THREAD_SAFETY_ANALYSIS;
    135 
    136  private:
    137   DISALLOW_COPY_AND_ASSIGN(JavaStackTraceHandler);
    138 };
    139 
    140 // Statically allocated so the the signal handler can Get access to it.
    141 extern FaultManager fault_manager;
    142 
    143 }       // namespace art
    144 #endif  // ART_RUNTIME_FAULT_HANDLER_H_
    145 
    146