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// Copyright (c) 2010, 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.
// linux_dumper.h: Define the google_breakpad::LinuxDumper class, which
// is a base class for extracting information of a crashed process. It
// was originally a complete implementation using the ptrace API, but
// has been refactored to allow derived implementations supporting both
// ptrace and core dump. A portion of the original implementation is now
// in google_breakpad::LinuxPtraceDumper (see linux_ptrace_dumper.h for
// details).
#ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINUX_DUMPER_H_
#define CLIENT_LINUX_MINIDUMP_WRITER_LINUX_DUMPER_H_
#include <assert.h>
#include <elf.h>
#if defined(__ANDROID__)
#include <link.h>
#endif
#include <linux/limits.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/user.h>
#include <vector>
#include "linux/dump_writer_common/mapping_info.h"
#include "linux/dump_writer_common/thread_info.h"
#include "common/linux/file_id.h"
#include "common/memory_allocator.h"
#include "google_breakpad/common/minidump_format.h"
#if defined(XP_LINUX)
# include "linux_utils.h"
#endif // defined(XP_LINUX)
namespace google_breakpad {
// Typedef for our parsing of the auxv variables in /proc/pid/auxv.
#if defined(__i386) || defined(__ARM_EABI__) || \
(defined(__mips__) && _MIPS_SIM == _ABIO32)
typedef Elf32_auxv_t elf_aux_entry;
#elif defined(__x86_64) || defined(__aarch64__) || \
(defined(__mips__) && _MIPS_SIM != _ABIO32)
typedef Elf64_auxv_t elf_aux_entry;
#endif
typedef __typeof__(((elf_aux_entry*) 0)->a_un.a_val) elf_aux_val_t;
// When we find the VDSO mapping in the process's address space, this
// is the name we use for it when writing it to the minidump.
// This should always be less than NAME_MAX!
const char kLinuxGateLibraryName[] = "linux-gate.so";
class LinuxDumper {
public:
// The |root_prefix| is prepended to mapping paths before opening them, which
// is useful if the crash originates from a chroot.
explicit LinuxDumper(pid_t pid, const char* root_prefix = "");
virtual ~LinuxDumper();
// Parse the data for |threads| and |mappings|.
virtual bool Init();
// Take any actions that could not be taken in Init(). LateInit() is
// called after all other caller's initialization is complete, and in
// particular after it has called ThreadsSuspend(), so that ptrace is
// available.
virtual bool LateInit();
// Return true if the dumper performs a post-mortem dump.
virtual bool IsPostMortem() const = 0;
// Suspend/resume all threads in the given process.
virtual bool ThreadsSuspend() = 0;
virtual bool ThreadsResume() = 0;
// Read information about the |index|-th thread of |threads_|.
// Returns true on success. One must have called |ThreadsSuspend| first.
virtual bool GetThreadInfoByIndex(size_t index, ThreadInfo* info) = 0;
// Read the name ofthe |index|-th thread of |threads_|.
// Returns true on success. One must have called |ThreadsSuspend| first.
virtual bool GetThreadNameByIndex(size_t index, char* name, size_t size) = 0;
size_t GetMainThreadIndex() const {
for (size_t i = 0; i < threads_.size(); ++i) {
if (threads_[i] == pid_) return i;
}
return -1u;
}
// These are only valid after a call to |Init|.
const wasteful_vector<pid_t> &threads() { return threads_; }
const wasteful_vector<MappingInfo*> &mappings() { return mappings_; }
const MappingInfo* FindMapping(const void* address) const;
// Find the mapping which the given memory address falls in. Unlike
// FindMapping, this method uses the unadjusted mapping address
// ranges from the kernel, rather than the ranges that have had the
// load bias applied.
const MappingInfo* FindMappingNoBias(uintptr_t address) const;
const wasteful_vector<elf_aux_val_t>& auxv() { return auxv_; }
// Find a block of memory to take as the stack given the top of stack pointer.
// stack: (output) the lowest address in the memory area
// stack_len: (output) the length of the memory area
// stack_top: the current top of the stack
bool GetStackInfo(const void** stack, size_t* stack_len, uintptr_t stack_top);
// Sanitize a copy of the stack by overwriting words that are not
// pointers with a sentinel (0x0defaced).
// stack_copy: a copy of the stack to sanitize. |stack_copy| might
// not be word aligned, but it represents word aligned
// data copied from another location.
// stack_len: the length of the allocation pointed to by |stack_copy|.
// stack_pointer: the address of the stack pointer (used to locate
// the stack mapping, as an optimization).
// sp_offset: the offset relative to stack_copy that reflects the
// current value of the stack pointer.
void SanitizeStackCopy(uint8_t* stack_copy, size_t stack_len,
uintptr_t stack_pointer, uintptr_t sp_offset);
// Test whether |stack_copy| contains a pointer-aligned word that
// could be an address within a given mapping.
// stack_copy: a copy of the stack to check. |stack_copy| might
// not be word aligned, but it represents word aligned
// data copied from another location.
// stack_len: the length of the allocation pointed to by |stack_copy|.
// sp_offset: the offset relative to stack_copy that reflects the
// current value of the stack pointer.
// mapping: the mapping against which to test stack words.
bool StackHasPointerToMapping(const uint8_t* stack_copy, size_t stack_len,
uintptr_t sp_offset,
const MappingInfo& mapping);
PageAllocator* allocator() { return &allocator_; }
// Copy content of |length| bytes from a given process |child|,
// starting from |src|, into |dest|. Returns true on success.
virtual bool CopyFromProcess(void* dest, pid_t child, const void* src,
size_t length) = 0;
// Builds a proc path for a certain pid for a node (/proc/<pid>/<node>).
// |path| is a character array of at least NAME_MAX bytes to return the
// result.|node| is the final node without any slashes. Returns true on
// success.
virtual bool BuildProcPath(char* path, pid_t pid, const char* node) const = 0;
// Generate a File ID from the .text section of a mapped entry.
// If not a member, mapping_id is ignored. This method can also manipulate the
// |mapping|.name to truncate "(deleted)" from the file name if necessary.
bool ElfFileIdentifierForMapping(const MappingInfo& mapping,
bool member,
unsigned int mapping_id,
wasteful_vector<uint8_t>& identifier);
void SetCrashInfoFromSigInfo(const siginfo_t& siginfo);
uintptr_t crash_address() const { return crash_address_; }
void set_crash_address(uintptr_t crash_address) {
crash_address_ = crash_address;
}
int crash_signal() const { return crash_signal_; }
void set_crash_signal(int crash_signal) { crash_signal_ = crash_signal; }
const char* GetCrashSignalString() const;
void set_crash_signal_code(int code) { crash_signal_code_ = code; }
int crash_signal_code() const { return crash_signal_code_; }
void set_crash_exception_info(const std::vector<uint64_t>& exception_info) {
assert(exception_info.size() <= MD_EXCEPTION_MAXIMUM_PARAMETERS);
crash_exception_info_ = exception_info;
}
const std::vector<uint64_t>& crash_exception_info() const {
return crash_exception_info_;
}
pid_t pid() const { return pid_; }
pid_t crash_thread() const { return crash_thread_; }
void set_crash_thread(pid_t crash_thread) { crash_thread_ = crash_thread; }
// Concatenates the |root_prefix_| and |mapping| path. Writes into |path| and
// returns true unless the string is too long.
bool GetMappingAbsolutePath(const MappingInfo& mapping,
char path[PATH_MAX]) const;
// Extracts the effective path and file name of from |mapping|. In most cases
// the effective name/path are just the mapping's path and basename. In some
// other cases, however, a library can be mapped from an archive (e.g., when
// loading .so libs from an apk on Android) and this method is able to
// reconstruct the original file name.
void GetMappingEffectiveNamePathAndVersion(const MappingInfo& mapping,
char* file_path,
size_t file_path_size,
char* file_name,
size_t file_name_size,
uint32_t* version);
protected:
bool ReadAuxv();
virtual bool EnumerateMappings();
virtual bool EnumerateThreads() = 0;
// For the case where a running program has been deleted, it'll show up in
// /proc/pid/maps as "/path/to/program (deleted)". If this is the case, then
// see if '/path/to/program (deleted)' matches /proc/pid/exe and return
// /proc/pid/exe in |path| so ELF identifier generation works correctly. This
// also checks to see if '/path/to/program (deleted)' exists, so it does not
// get fooled by a poorly named binary.
// For programs that don't end with ' (deleted)', this is a no-op.
// This assumes |path| is a buffer with length NAME_MAX.
// Returns true if |path| is modified.
bool HandleDeletedFileInMapping(char* path) const;
// ID of the crashed process.
const pid_t pid_;
// Path of the root directory to which mapping paths are relative.
const char* const root_prefix_;
// Virtual address at which the process crashed.
uintptr_t crash_address_;
// Signal that terminated the crashed process.
int crash_signal_;
// The code associated with |crash_signal_|.
int crash_signal_code_;
// The additional fields associated with |crash_signal_|.
std::vector<uint64_t> crash_exception_info_;
// ID of the crashed thread.
pid_t crash_thread_;
mutable PageAllocator allocator_;
// IDs of all the threads.
wasteful_vector<pid_t> threads_;
// Info from /proc/<pid>/maps.
wasteful_vector<MappingInfo*> mappings_;
// Info from /proc/<pid>/auxv
wasteful_vector<elf_aux_val_t> auxv_;
private:
bool IsIPCSharedMemorySegment(const char* name);
#if defined(__ANDROID__)
// Android M and later support packed ELF relocations in shared libraries.
// Packing relocations changes the vaddr of the LOAD segments, such that
// the effective load bias is no longer the same as the start address of
// the memory mapping containing the executable parts of the library. The
// packing is applied to the stripped library run on the target, but not to
// any other library, and in particular not to the library used to generate
// breakpad symbols. As a result, we need to adjust the |start_addr| for
// any mapping that results from a shared library that contains Android
// packed relocations, so that it properly represents the effective library
// load bias. The following functions support this adjustment.
// Check that a given mapping at |start_addr| is for an ELF shared library.
// If it is, place the ELF header in |ehdr| and return true.
// The first LOAD segment in an ELF shared library has offset zero, so the
// ELF file header is at the start of this map entry, and in already mapped
// memory.
bool GetLoadedElfHeader(uintptr_t start_addr, ElfW(Ehdr)* ehdr);
// For the ELF file mapped at |start_addr|, iterate ELF program headers to
// find the min vaddr of all program header LOAD segments, the vaddr for
// the DYNAMIC segment, and a count of DYNAMIC entries. Return values in
// |min_vaddr_ptr|, |dyn_vaddr_ptr|, and |dyn_count_ptr|.
// The program header table is also in already mapped memory.
void ParseLoadedElfProgramHeaders(ElfW(Ehdr)* ehdr,
uintptr_t start_addr,
uintptr_t* min_vaddr_ptr,
uintptr_t* dyn_vaddr_ptr,
size_t* dyn_count_ptr);
// Search the DYNAMIC tags for the ELF file with the given |load_bias|, and
// return true if the tags indicate that the file contains Android packed
// relocations. Dynamic tags are found at |dyn_vaddr| past the |load_bias|.
bool HasAndroidPackedRelocations(uintptr_t load_bias,
uintptr_t dyn_vaddr,
size_t dyn_count);
// If the ELF file mapped at |start_addr| contained Android packed
// relocations, return the load bias that the system linker (or Chromium
// crazy linker) will have used. If the file did not contain Android
// packed relocations, returns |start_addr|, indicating that no adjustment
// is necessary.
// The effective load bias is |start_addr| adjusted downwards by the
// min vaddr in the library LOAD segments.
uintptr_t GetEffectiveLoadBias(ElfW(Ehdr)* ehdr, uintptr_t start_addr);
// Called from LateInit(). Iterates |mappings_| and rewrites the |start_addr|
// field of any that represent ELF shared libraries with Android packed
// relocations, so that |start_addr| is the load bias that the system linker
// (or Chromium crazy linker) used. This value matches the addresses produced
// when the non-relocation-packed library is used for breakpad symbol
// generation.
void LatePostprocessMappings();
#endif // __ANDROID__
};
} // namespace google_breakpad
#endif // CLIENT_LINUX_HANDLER_LINUX_DUMPER_H_