// Copyright (c) 2006, Google Inc.

// All rights reserved.

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

//

//     * Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above

// copyright notice, this list of conditions and the following disclaimer

// in the documentation and/or other materials provided with the

// distribution.

//     * Neither the name of Google Inc. nor the names of its

// contributors may be used to endorse or promote products derived from

// this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

//

// Author: Satoru Takabayashi

//

// This library provides Symbolize() function that symbolizes program

// counters to their corresponding symbol names on linux platforms.

// This library has a minimal implementation of an ELF symbol table

// reader (i.e. it doesn't depend on libelf, etc.).

//

// The algorithm used in Symbolize() is as follows.

//

//   1. Go through a list of maps in /proc/self/maps and find the map

//   containing the program counter.

//

//   2. Open the mapped file and find a regular symbol table inside.

//   Iterate over symbols in the symbol table and look for the symbol

//   containing the program counter.  If such a symbol is found,

//   obtain the symbol name, and demangle the symbol if possible.

//   If the symbol isn't found in the regular symbol table (binary is

//   stripped), try the same thing with a dynamic symbol table.

//

// Note that Symbolize() is originally implemented to be used in

// FailureSignalHandler() in base/google.cc.  Hence it doesn't use

// malloc() and other unsafe operations.  It should be both

// thread-safe and async-signal-safe.

#ifndef BASE_SYMBOLIZE_H_

#define BASE_SYMBOLIZE_H_

#include "utilities.h"

#include "config.h"

#include "glog/logging.h"

#ifdef HAVE_SYMBOLIZE

#if defined(__ELF__)  // defined by gcc

#if defined(__OpenBSD__)

#include <sys/exec_elf.h>

#else

#include <elf.h>

#endif

#if !defined(ANDROID)

#include <link.h>  // For ElfW() macro.

#endif

// For systems where SIZEOF_VOID_P is not defined, determine it

// based on __LP64__ (defined by gcc on 64-bit systems)

#if !defined(SIZEOF_VOID_P)

# if defined(__LP64__)

#  define SIZEOF_VOID_P 8

# else

#  define SIZEOF_VOID_P 4

# endif

#endif

// If there is no ElfW macro, let's define it by ourself.

#ifndef ElfW

# if SIZEOF_VOID_P == 4

#  define ElfW(type) Elf32_##type

# elif SIZEOF_VOID_P == 8

#  define ElfW(type) Elf64_##type

# else

#  error "Unknown sizeof(void *)"

# endif

#endif

_START_GOOGLE_NAMESPACE_

// Gets the section header for the given name, if it exists. Returns true on

// success. Otherwise, returns false.

bool GetSectionHeaderByName(int fd, const char *name, size_t name_len,

                            ElfW(Shdr) *out);

_END_GOOGLE_NAMESPACE_

#endif  /* __ELF__ */

_START_GOOGLE_NAMESPACE_

// Restrictions on the callbacks that follow:

//  - The callbacks must not use heaps but only use stacks.

//  - The callbacks must be async-signal-safe.

// Installs a callback function, which will be called right before a symbol name

// is printed. The callback is intended to be used for showing a file name and a

// line number preceding a symbol name.

// "fd" is a file descriptor of the object file containing the program

// counter "pc". The callback function should write output to "out"

// and return the size of the output written. On error, the callback

// function should return -1.

typedef int (*SymbolizeCallback)(int fd, void *pc, char *out, size_t out_size,

                                 uint64 relocation);

void InstallSymbolizeCallback(SymbolizeCallback callback);

// Installs a callback function, which will be called instead of

// OpenObjectFileContainingPcAndGetStartAddress.  The callback is expected

// to searches for the object file (from /proc/self/maps) that contains

// the specified pc.  If found, sets |start_address| to the start address

// of where this object file is mapped in memory, sets the module base

// address into |base_address|, copies the object file name into

// |out_file_name|, and attempts to open the object file.  If the object

// file is opened successfully, returns the file descriptor.  Otherwise,

// returns -1.  |out_file_name_size| is the size of the file name buffer

// (including the null-terminator).

typedef int (*SymbolizeOpenObjectFileCallback)(uint64_t pc,

                                               uint64_t &start_address,

                                               uint64_t &base_address,

                                               char *out_file_name,

                                               int out_file_name_size);

void InstallSymbolizeOpenObjectFileCallback(

    SymbolizeOpenObjectFileCallback callback);

_END_GOOGLE_NAMESPACE_

#endif

_START_GOOGLE_NAMESPACE_

// Symbolizes a program counter.  On success, returns true and write the

// symbol name to "out".  The symbol name is demangled if possible

// (supports symbols generated by GCC 3.x or newer).  Otherwise,

// returns false.

bool Symbolize(void *pc, char *out, int out_size);

_END_GOOGLE_NAMESPACE_

#endif  // BASE_SYMBOLIZE_H_