ptrace.h

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
/* Useful ptrace() utility functions. */
 
#ifndef _CORKSCREW_PTRACE_H
#define _CORKSCREW_PTRACE_H
 
#include <corkscrew/map_info.h>
#include <corkscrew/symbol_table.h>
 
#include <sys/types.h>
#include <stdbool.h>
#include <stdint.h>
 
#ifdef __cplusplus
extern "C"
{
#endif
 
  /* Stores information about a process that is used for several different
   * ptrace() based operations. */
  typedef struct
  {
    map_info_t* map_info_list;
  } ptrace_context_t;
 
  /* Describes how to access memory from a process. */
  typedef struct
  {
    pid_t tid;
    const map_info_t* map_info_list;
  } memory_t;
 
#ifdef __i386__
  /* ptrace() register context. */
  typedef struct pt_regs_x86
  {
    uint32_t ebx;
    uint32_t ecx;
    uint32_t edx;
    uint32_t esi;
    uint32_t edi;
    uint32_t ebp;
    uint32_t eax;
    uint32_t xds;
    uint32_t xes;
    uint32_t xfs;
    uint32_t xgs;
    uint32_t orig_eax;
    uint32_t eip;
    uint32_t xcs;
    uint32_t eflags;
    uint32_t esp;
    uint32_t xss;
  } pt_regs_x86_t;
#endif
 
#ifdef __mips__
  /* ptrace() GET_REGS context. */
  typedef struct pt_regs_mips
  {
    uint64_t regs[32];
    uint64_t lo;
    uint64_t hi;
    uint64_t cp0_epc;
    uint64_t cp0_badvaddr;
    uint64_t cp0_status;
    uint64_t cp0_cause;
  } pt_regs_mips_t;
#endif
 
  /*
   * Initializes a memory structure for accessing memory from this process.
   */
  void init_memory(memory_t* memory, const map_info_t* map_info_list);
 
  /*
   * Initializes a memory structure for accessing memory from another process
   * using ptrace().
   */
  void init_memory_ptrace(memory_t* memory, pid_t tid);
 
  /*
   * Reads a word of memory safely.
   * If the memory is local, ensures that the address is readable before dereferencing it.
   * Returns false and a value of 0xffffffff if the word could not be read.
   */
  bool try_get_word(const memory_t* memory, uintptr_t ptr, uint32_t* out_value);
 
  /*
   * Reads a word of memory safely using ptrace().
   * Returns false and a value of 0xffffffff if the word could not be read.
   */
  bool try_get_word_ptrace(pid_t tid, uintptr_t ptr, uint32_t* out_value);
 
  /*
   * Loads information needed for examining a remote process using ptrace().
   * The caller must already have successfully attached to the process
   * using ptrace().
   *
   * The context can be used for any threads belonging to that process
   * assuming ptrace() is attached to them before performing the actual
   * unwinding.  The context can continue to be used to decode backtraces
   * even after ptrace() has been detached from the process.
   */
  ptrace_context_t* load_ptrace_context(pid_t pid);
 
  /*
   * Frees a ptrace context.
   */
  void free_ptrace_context(ptrace_context_t* context);
 
  /*
   * Finds a symbol using ptrace.
   * Returns the containing map and information about the symbol, or
   * NULL if one or the other is not available.
   */
  void find_symbol_ptrace(const ptrace_context_t* context, uintptr_t addr,
                          const map_info_t** out_map_info, const symbol_t** out_symbol);
 
#ifdef __cplusplus
}
#endif
 
#endif // _CORKSCREW_PTRACE_H