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Implement core dump to minidump conversion.

Browse source 
This patch is part of a bigger patch that helps merging the breakpad code
with the modified version in Chromium OS.

Specifically, this patch makes the following changes:
1. Turn the LinuxDumper class into a base class and move ptrace related
   code into a new derived class, LinuxPtraceDumper.
2. Add a LinuxCoreDumper class, which is derived from LinuxDumper, to
   extract information from a crashed process via a core dump file instead
   of ptrace.
3. Add a WriteMinidumpFromCore function to
     src/client/linux/minidump_writer/minidump_writer.h,
   which uses LinuxCoreDumper to extract information from a core dump file.
4. Add a core2md utility, which simply wraps WriteMinidumpFromCore, for
   converting a core dump to a minidump.

BUG=455
TEST=Tested the following:
1. Build on 32-bit and 64-bit Linux with gcc 4.4.3 and gcc 4.6.
2. Build on Mac OS X 10.6.8 with gcc 4.2 and clang 3.0 (with latest gmock).
3. All unit tests pass.
4. Run Chromium OS tests to test core2md.
Review URL: http://breakpad.appspot.com/343001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@905 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
benchan@chromium.org 2012-01-19 07:14:51 +00:00
parent 3822e36b20
commit 30566abed8
16 changed files with 1277 additions and 430 deletions
Download patch file Download diff file Expand all files Collapse all files

234
src/client/linux/minidump_writer/linux_core_dumper.cc Normal file
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@ -0,0 +1,234 @@
// Copyright (c) 2012, 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_core_dumper.cc: Implement google_breakpad::LinuxCoreDumper.
// See linux_core_dumper.h for details.
#include "client/linux/minidump_writer/linux_core_dumper.h"
#include <asm/ptrace.h>
#include <assert.h>
#include <elf.h>
#include <stdio.h>
#include <string.h>
#include <sys/procfs.h>
#include "common/linux/linux_libc_support.h"
namespace google_breakpad {
LinuxCoreDumper::LinuxCoreDumper(pid_t pid,
const char* core_path,
const char* procfs_path)
: LinuxDumper(pid),
core_path_(core_path),
procfs_path_(procfs_path),
thread_infos_(&allocator_, 8) {
assert(core_path_);
}
bool LinuxCoreDumper::BuildProcPath(char* path, pid_t pid,
const char* node) const {
if (!path || !node)
return false;
size_t node_len = my_strlen(node);
if (node_len == 0)
return false;
size_t procfs_path_len = my_strlen(procfs_path_);
size_t total_length = procfs_path_len + 1 + node_len;
if (total_length >= NAME_MAX)
return false;
memcpy(path, procfs_path_, procfs_path_len);
path[procfs_path_len] = '/';
memcpy(path + procfs_path_len + 1, node, node_len);
path[total_length] = '\0';
return true;
}
void LinuxCoreDumper::CopyFromProcess(void* dest, pid_t child,
const void* src, size_t length) {
ElfCoreDump::Addr virtual_address = reinterpret_cast<ElfCoreDump::Addr>(src);
// TODO(benchan): Investigate whether the data to be copied could span
// across multiple segments in the core dump file. ElfCoreDump::CopyData
// and this method do not handle that case yet.
if (!core_.CopyData(dest, virtual_address, length)) {
// If the data segment is not found in the core dump, fill the result
// with marker characters.
memset(dest, 0xab, length);
}
}
bool LinuxCoreDumper::GetThreadInfoByIndex(size_t index, ThreadInfo* info) {
if (index >= thread_infos_.size())
return false;
*info = thread_infos_[index];
const uint8_t* stack_pointer;
#if defined(__i386)
memcpy(&stack_pointer, &info->regs.esp, sizeof(info->regs.esp));
#elif defined(__x86_64)
memcpy(&stack_pointer, &info->regs.rsp, sizeof(info->regs.rsp));
#elif defined(__ARM_EABI__)
memcpy(&stack_pointer, &info->regs.ARM_sp, sizeof(info->regs.ARM_sp));
#else
#error "This code hasn't been ported to your platform yet."
#endif
return GetStackInfo(&info->stack, &info->stack_len,
reinterpret_cast<uintptr_t>(stack_pointer));
}
bool LinuxCoreDumper::IsPostMortem() const {
return true;
}
bool LinuxCoreDumper::ThreadsSuspend() {
return true;
}
bool LinuxCoreDumper::ThreadsResume() {
return true;
}
bool LinuxCoreDumper::EnumerateThreads() {
if (!mapped_core_file_.Map(core_path_)) {
fprintf(stderr, "Could not map core dump file into memory\n");
return false;
}
core_.SetContent(mapped_core_file_.content());
if (!core_.IsValid()) {
fprintf(stderr, "Invalid core dump file\n");
return false;
}
ElfCoreDump::Note note = core_.GetFirstNote();
if (!note.IsValid()) {
fprintf(stderr, "PT_NOTE section not found\n");
return false;
}
bool first_thread = true;
do {
ElfCoreDump::Word type = note.GetType();
MemoryRange name = note.GetName();
MemoryRange description = note.GetDescription();
if (type == 0 || name.IsEmpty() || description.IsEmpty()) {
fprintf(stderr, "Could not found a valid PT_NOTE.\n");
return false;
}
// Based on write_note_info() in linux/kernel/fs/binfmt_elf.c, notes are
// ordered as follows (NT_PRXFPREG and NT_386_TLS are i386 specific):
// Thread Name Type
// -------------------------------------------------------------------
// 1st thread CORE NT_PRSTATUS
// process-wide CORE NT_PRPSINFO
// process-wide CORE NT_AUXV
// 1st thread CORE NT_FPREGSET
// 1st thread LINUX NT_PRXFPREG
// 1st thread LINUX NT_386_TLS
//
// 2nd thread CORE NT_PRSTATUS
// 2nd thread CORE NT_FPREGSET
// 2nd thread LINUX NT_PRXFPREG
// 2nd thread LINUX NT_386_TLS
//
// 3rd thread CORE NT_PRSTATUS
// 3rd thread CORE NT_FPREGSET
// 3rd thread LINUX NT_PRXFPREG
// 3rd thread LINUX NT_386_TLS
//
// The following code only works if notes are ordered as expected.
switch (type) {
case NT_PRSTATUS: {
if (description.length() != sizeof(elf_prstatus)) {
fprintf(stderr, "Found NT_PRSTATUS descriptor of unexpected size\n");
return false;
}
const elf_prstatus* status =
reinterpret_cast<const elf_prstatus*>(description.data());
pid_t pid = status->pr_pid;
ThreadInfo info;
memset(&info, 0, sizeof(ThreadInfo));
info.tgid = status->pr_pgrp;
info.ppid = status->pr_ppid;
memcpy(&info.regs, status->pr_reg, sizeof(info.regs));
if (first_thread) {
crash_thread_ = pid;
crash_signal_ = status->pr_info.si_signo;
}
first_thread = false;
threads_.push_back(pid);
thread_infos_.push_back(info);
break;
}
#if defined(__i386) || defined(__x86_64)
case NT_FPREGSET: {
if (thread_infos_.empty())
return false;
ThreadInfo* info = &thread_infos_.back();
if (description.length() != sizeof(info->fpregs)) {
fprintf(stderr, "Found NT_FPREGSET descriptor of unexpected size\n");
return false;
}
memcpy(&info->fpregs, description.data(), sizeof(info->fpregs));
break;
}
#endif
#if defined(__i386)
case NT_PRXFPREG: {
if (thread_infos_.empty())
return false;
ThreadInfo* info = &thread_infos_.back();
if (description.length() != sizeof(info->fpxregs)) {
fprintf(stderr, "Found NT_PRXFPREG descriptor of unexpected size\n");
return false;
}
memcpy(&info->fpxregs, description.data(), sizeof(info->fpxregs));
break;
}
#endif
}
note = note.GetNextNote();
} while (note.IsValid());
return true;
}
} // namespace google_breakpad

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src/client/linux/minidump_writer/linux_core_dumper.h Normal file
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@ -0,0 +1,122 @@
// Copyright (c) 2012, 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_core_dumper.h: Define the google_breakpad::LinuxCoreDumper
// class, which is derived from google_breakpad::LinuxDumper to extract
// information from a crashed process via its core dump and proc files.
#ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINUX_CORE_DUMPER_H_
#define CLIENT_LINUX_MINIDUMP_WRITER_LINUX_CORE_DUMPER_H_
#include "client/linux/minidump_writer/linux_dumper.h"
#include "common/linux/elf_core_dump.h"
#include "common/linux/memory_mapped_file.h"
namespace google_breakpad {
class LinuxCoreDumper : public LinuxDumper {
public:
// Constructs a dumper for extracting information of a given process
// with a process ID of |pid| via its core dump file at |core_path| and
// its proc files at |procfs_path|. If |procfs_path| is a copy of
// /proc/<pid>, it should contain the following files:
// auxv, cmdline, environ, exe, maps, status
LinuxCoreDumper(pid_t pid, const char* core_path, const char* procfs_path);
// Implements LinuxDumper::BuildProcPath().
// 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. Return true on
// success.
//
// As this dumper performs a post-mortem dump and makes use of a copy
// of the proc files of the crashed process, this derived method does
// not actually make use of |pid| and always returns a subpath of
// |procfs_path_| regardless of whether |pid| corresponds to the main
// process or a thread of the process, i.e. assuming both the main process
// and its threads have the following proc files with the same content:
// auxv, cmdline, environ, exe, maps, status
virtual bool BuildProcPath(char* path, pid_t pid, const char* node) const;
// Implements LinuxDumper::CopyFromProcess().
// Copies content of |length| bytes from a given process |child|,
// starting from |src|, into |dest|. This method extracts the content
// the core dump and fills |dest| with a sequence of marker bytes
// if the expected data is not found in the core dump.
virtual void CopyFromProcess(void* dest, pid_t child, const void* src,
size_t length);
// Implements LinuxDumper::GetThreadInfoByIndex().
// Reads 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);
// Implements LinuxDumper::IsPostMortem().
// Always returns true to indicate that this dumper performs a
// post-mortem dump of a crashed process via a core dump file.
virtual bool IsPostMortem() const;
// Implements LinuxDumper::ThreadsSuspend().
// As the dumper performs a post-mortem dump via a core dump file,
// there is no threads to suspend. This method does nothing and
// always returns true.
virtual bool ThreadsSuspend();
// Implements LinuxDumper::ThreadsResume().
// As the dumper performs a post-mortem dump via a core dump file,
// there is no threads to resume. This method does nothing and
// always returns true.
virtual bool ThreadsResume();
protected:
// Implements LinuxDumper::EnumerateThreads().
// Enumerates all threads of the given process into |threads_|.
virtual bool EnumerateThreads();
private:
// Path of the core dump file.
const char* core_path_;
// Path of the directory containing the proc files of the given process,
// which is usually a copy of /proc/<pid>.
const char* procfs_path_;
// Memory-mapped core dump file at |core_path_|.
MemoryMappedFile mapped_core_file_;
// Content of the core dump file.
ElfCoreDump core_;
// Thread info found in the core dump file.
wasteful_vector<ThreadInfo> thread_infos_;
};
} // namespace google_breakpad
#endif // CLIENT_LINUX_HANDLER_LINUX_CORE_DUMPER_H_

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src/client/linux/minidump_writer/linux_core_dumper_unittest.cc Normal file
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@ -0,0 +1,117 @@
// Copyright (c) 2012, 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_core_dumper_unittest.cc:
// Unit tests for google_breakpad::LinuxCoreDumoer.
#include "breakpad_googletest_includes.h"
#include "client/linux/minidump_writer/linux_core_dumper.h"
#include "common/linux/tests/crash_generator.h"
using std::string;
using namespace google_breakpad;
TEST(LinuxCoreDumperTest, BuildProcPath) {
const pid_t pid = getpid();
const char procfs_path[] = "/procfs_copy";
LinuxCoreDumper dumper(getpid(), "core_file", procfs_path);
char maps_path[NAME_MAX] = "";
char maps_path_expected[NAME_MAX];
snprintf(maps_path_expected, sizeof(maps_path_expected),
"%s/maps", procfs_path);
EXPECT_TRUE(dumper.BuildProcPath(maps_path, pid, "maps"));
EXPECT_STREQ(maps_path_expected, maps_path);
EXPECT_FALSE(dumper.BuildProcPath(NULL, pid, "maps"));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, ""));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, NULL));
char long_node[NAME_MAX];
size_t long_node_len = NAME_MAX - strlen(procfs_path) - 1;
memset(long_node, 'a', long_node_len);
long_node[long_node_len] = '\0';
EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, long_node));
}
TEST(LinuxCoreDumperTest, VerifyDumpWithMultipleThreads) {
CrashGenerator crash_generator;
if (!crash_generator.HasDefaultCorePattern()) {
fprintf(stderr, "LinuxCoreDumperTest.VerifyDumpWithMultipleThreads test"
"is skipped due to non-default core pattern\n");
return;
}
const unsigned kNumOfThreads = 3;
const unsigned kCrashThread = 1;
const int kCrashSignal = SIGABRT;
pid_t child_pid;
// TODO(benchan): Revert to use ASSERT_TRUE once the flakiness in
// CrashGenerator is identified and fixed.
if (!crash_generator.CreateChildCrash(kNumOfThreads, kCrashThread,
kCrashSignal, &child_pid)) {
fprintf(stderr, "LinuxCoreDumperTest.VerifyDumpWithMultipleThreads test"
"is skipped due to no core dump generated\n");
return;
}
pid_t pid = getpid();
const char* core_file = crash_generator.GetCoreFilePath().c_str();
// Since CrashGenerator::CreateChildCrash() simply crashed a fork of
// this process, we expect that those proc files, which are used by
// LinuxCoreDumper, of crashed child process have the same content of
// this process. So we simply pass the proc files of this process to
// LinuxCoreDumper.
char procfs_path[NAME_MAX];
snprintf(procfs_path, NAME_MAX, "/proc/%d", pid);
LinuxCoreDumper dumper(child_pid, core_file, procfs_path);
dumper.Init();
EXPECT_TRUE(dumper.IsPostMortem());
// These are no-ops and should always return true.
EXPECT_TRUE(dumper.ThreadsSuspend());
EXPECT_TRUE(dumper.ThreadsResume());
// LinuxCoreDumper cannot determine the crash address and thus it always
// sets the crash address to 0.
EXPECT_EQ(0, dumper.crash_address());
EXPECT_EQ(kCrashSignal, dumper.crash_signal());
EXPECT_EQ(crash_generator.GetThreadId(kCrashThread),
dumper.crash_thread());
EXPECT_EQ(kNumOfThreads, dumper.threads().size());
for (unsigned i = 0; i < kNumOfThreads; ++i) {
ThreadInfo info;
EXPECT_TRUE(dumper.GetThreadInfoByIndex(i, &info));
EXPECT_EQ(getpid(), info.ppid);
}
}

275
src/client/linux/minidump_writer/linux_dumper.cc
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@ -27,6 +27,9 @@
// (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.cc: Implement google_breakpad::LinuxDumper.
// See linux_dumper.h for details.
// This code deals with the mechanics of getting information about a crashed
// process. Since this code may run in a compromised address space, the same
// rules apply as detailed at the top of minidump_writer.h: no libc calls and
@ -34,25 +37,12 @@
#include "client/linux/minidump_writer/linux_dumper.h"
#include <asm/ptrace.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#if !defined(__ANDROID__)
#include <link.h>
#endif
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <unistd.h>
#include <algorithm>
#include "client/linux/minidump_writer/directory_reader.h"
#include "client/linux/minidump_writer/line_reader.h"
#include "common/linux/file_id.h"
#include "common/linux/linux_libc_support.h"
@ -63,48 +53,6 @@
static const char kMappedFileUnsafePrefix[] = "/dev/";
static const char kDeletedSuffix[] = " (deleted)";
// Suspend a thread by attaching to it.
static bool SuspendThread(pid_t pid) {
// This may fail if the thread has just died or debugged.
errno = 0;
if (sys_ptrace(PTRACE_ATTACH, pid, NULL, NULL) != 0 &&
errno != 0) {
return false;
}
while (sys_waitpid(pid, NULL, __WALL) < 0) {
if (errno != EINTR) {
sys_ptrace(PTRACE_DETACH, pid, NULL, NULL);
return false;
}
}
#if defined(__i386) || defined(__x86_64)
// On x86, the stack pointer is NULL or -1, when executing trusted code in
// the seccomp sandbox. Not only does this cause difficulties down the line
// when trying to dump the thread's stack, it also results in the minidumps
// containing information about the trusted threads. This information is
// generally completely meaningless and just pollutes the minidumps.
// We thus test the stack pointer and exclude any threads that are part of
// the seccomp sandbox's trusted code.
user_regs_struct regs;
if (sys_ptrace(PTRACE_GETREGS, pid, NULL, &regs) == -1 ||
#if defined(__i386)
!regs.esp
#elif defined(__x86_64)
!regs.rsp
#endif
) {
sys_ptrace(PTRACE_DETACH, pid, NULL, NULL);
return false;
}
#endif
return true;
}
// Resume a thread by detaching from it.
static bool ResumeThread(pid_t pid) {
return sys_ptrace(PTRACE_DETACH, pid, NULL, NULL) >= 0;
}
inline static bool IsMappedFileOpenUnsafe(
const google_breakpad::MappingInfo& mapping) {
// It is unsafe to attempt to open a mapped file that lives under /dev,
@ -123,7 +71,6 @@ LinuxDumper::LinuxDumper(pid_t pid)
crash_address_(0),
crash_signal_(0),
crash_thread_(0),
threads_suspended_(false),
threads_(&allocator_, 8),
mappings_(&allocator_) {
}
@ -135,80 +82,6 @@ bool LinuxDumper::Init() {
return EnumerateThreads() && EnumerateMappings();
}
bool LinuxDumper::ThreadsSuspend() {
if (threads_suspended_)
return true;
for (size_t i = 0; i < threads_.size(); ++i) {
if (!SuspendThread(threads_[i])) {
// If the thread either disappeared before we could attach to it, or if
// it was part of the seccomp sandbox's trusted code, it is OK to
// silently drop it from the minidump.
memmove(&threads_[i], &threads_[i+1],
(threads_.size() - i - 1) * sizeof(threads_[i]));
threads_.resize(threads_.size() - 1);
--i;
}
}
threads_suspended_ = true;
return threads_.size() > 0;
}
bool LinuxDumper::ThreadsResume() {
if (!threads_suspended_)
return false;
bool good = true;
for (size_t i = 0; i < threads_.size(); ++i)
good &= ResumeThread(threads_[i]);
threads_suspended_ = false;
return good;
}
void
LinuxDumper::BuildProcPath(char* path, pid_t pid, const char* node) const {
assert(path);
if (!path) {
return;
}
path[0] = '\0';
const unsigned pid_len = my_int_len(pid);
assert(node);
if (!node) {
return;
}
size_t node_len = my_strlen(node);
assert(node_len < NAME_MAX);
if (node_len >= NAME_MAX) {
return;
}
assert(node_len > 0);
if (node_len == 0) {
return;
}
assert(pid > 0);
if (pid <= 0) {
return;
}
const size_t total_length = 6 + pid_len + 1 + node_len;
assert(total_length < NAME_MAX);
if (total_length >= NAME_MAX) {
return;
}
memcpy(path, "/proc/", 6);
my_itos(path + 6, pid, pid_len);
memcpy(path + 6 + pid_len, "/", 1);
memcpy(path + 6 + pid_len + 1, node, node_len);
path[total_length] = '\0';
}
bool
LinuxDumper::ElfFileIdentifierForMapping(const MappingInfo& mapping,
bool member,
@ -261,10 +134,8 @@ LinuxDumper::ElfFileIdentifierForMapping(const MappingInfo& mapping,
void*
LinuxDumper::FindBeginningOfLinuxGateSharedLibrary(const pid_t pid) const {
char auxv_path[NAME_MAX];
BuildProcPath(auxv_path, pid, "auxv");
// If BuildProcPath errors out due to invalid input, we'll handle it when
// we try to sys_open the file.
if (!BuildProcPath(auxv_path, pid, "auxv"))
return NULL;
// Find the AT_SYSINFO_EHDR entry for linux-gate.so
// See http://www.trilithium.com/johan/2005/08/linux-gate/ for more
@ -290,7 +161,8 @@ LinuxDumper::FindBeginningOfLinuxGateSharedLibrary(const pid_t pid) const {
bool LinuxDumper::EnumerateMappings() {
char maps_path[NAME_MAX];
BuildProcPath(maps_path, pid_, "maps");
if (!BuildProcPath(maps_path, pid_, "maps"))
return false;
// linux_gate_loc is the beginning of the kernel's mapping of
// linux-gate.so in the process. It doesn't actually show up in the
@ -359,118 +231,6 @@ bool LinuxDumper::EnumerateMappings() {
return !mappings_.empty();
}
// Parse /proc/$pid/task to list all the threads of the process identified by
// pid.
bool LinuxDumper::EnumerateThreads() {
char task_path[NAME_MAX];
BuildProcPath(task_path, pid_, "task");
const int fd = sys_open(task_path, O_RDONLY | O_DIRECTORY, 0);
if (fd < 0)
return false;
DirectoryReader* dir_reader = new(allocator_) DirectoryReader(fd);
// The directory may contain duplicate entries which we filter by assuming
// that they are consecutive.
int last_tid = -1;
const char* dent_name;
while (dir_reader->GetNextEntry(&dent_name)) {
if (my_strcmp(dent_name, ".") &&
my_strcmp(dent_name, "..")) {
int tid = 0;
if (my_strtoui(&tid, dent_name) &&
last_tid != tid) {
last_tid = tid;
threads_.push_back(tid);
}
}
dir_reader->PopEntry();
}
sys_close(fd);
return true;
}
// Read thread info from /proc/$pid/status.
// Fill out the |tgid|, |ppid| and |pid| members of |info|. If unavailable,
// these members are set to -1. Returns true iff all three members are
// available.
bool LinuxDumper::GetThreadInfoByIndex(size_t index, ThreadInfo* info) {
if (index >= threads_.size())
return false;
pid_t tid = threads_[index];
assert(info != NULL);
char status_path[NAME_MAX];
BuildProcPath(status_path, tid, "status");
const int fd = sys_open(status_path, O_RDONLY, 0);
if (fd < 0)
return false;
LineReader* const line_reader = new(allocator_) LineReader(fd);
const char* line;
unsigned line_len;
info->ppid = info->tgid = -1;
while (line_reader->GetNextLine(&line, &line_len)) {
if (my_strncmp("Tgid:\t", line, 6) == 0) {
my_strtoui(&info->tgid, line + 6);
} else if (my_strncmp("PPid:\t", line, 6) == 0) {
my_strtoui(&info->ppid, line + 6);
}
line_reader->PopLine(line_len);
}
if (info->ppid == -1 || info->tgid == -1)
return false;
if (sys_ptrace(PTRACE_GETREGS, tid, NULL, &info->regs) == -1) {
return false;
}
#if !defined(__ANDROID__)
if (sys_ptrace(PTRACE_GETFPREGS, tid, NULL, &info->fpregs) == -1) {
return false;
}
#endif
#if defined(__i386)
if (sys_ptrace(PTRACE_GETFPXREGS, tid, NULL, &info->fpxregs) == -1)
return false;
#endif
#if defined(__i386) || defined(__x86_64)
for (unsigned i = 0; i < ThreadInfo::kNumDebugRegisters; ++i) {
if (sys_ptrace(
PTRACE_PEEKUSER, tid,
reinterpret_cast<void*> (offsetof(struct user,
u_debugreg[0]) + i *
sizeof(debugreg_t)),
&info->dregs[i]) == -1) {
return false;
}
}
#endif
const uint8_t* stack_pointer;
#if defined(__i386)
memcpy(&stack_pointer, &info->regs.esp, sizeof(info->regs.esp));
#elif defined(__x86_64)
memcpy(&stack_pointer, &info->regs.rsp, sizeof(info->regs.rsp));
#elif defined(__ARM_EABI__)
memcpy(&stack_pointer, &info->regs.ARM_sp, sizeof(info->regs.ARM_sp));
#else
#error "This code hasn't been ported to your platform yet."
#endif
return GetStackInfo(&info->stack, &info->stack_len,
(uintptr_t) stack_pointer);
}
// Get information about the stack, given the stack pointer. We don't try to
// walk the stack since we might not have all the information needed to do
// unwind. So we just grab, up to, 32k of stack.
@ -497,24 +257,6 @@ bool LinuxDumper::GetStackInfo(const void** stack, size_t* stack_len,
return true;
}
void LinuxDumper::CopyFromProcess(void* dest, pid_t child, const void* src,
size_t length) {
unsigned long tmp = 55;
size_t done = 0;
static const size_t word_size = sizeof(tmp);
uint8_t* const local = (uint8_t*) dest;
uint8_t* const remote = (uint8_t*) src;
while (done < length) {
const size_t l = length - done > word_size ? word_size : length - done;
if (sys_ptrace(PTRACE_PEEKDATA, child, remote + done, &tmp) == -1) {
tmp = 0;
}
memcpy(local + done, &tmp, l);
done += l;
}
}
// Find the mapping which the given memory address falls in.
const MappingInfo* LinuxDumper::FindMapping(const void* address) const {
const uintptr_t addr = (uintptr_t) address;
@ -544,7 +286,8 @@ bool LinuxDumper::HandleDeletedFileInMapping(char* path) const {
// Check |path| against the /proc/pid/exe 'symlink'.
char exe_link[NAME_MAX];
char new_path[NAME_MAX];
BuildProcPath(exe_link, pid_, "exe");
if (!BuildProcPath(exe_link, pid_, "exe"))
return false;
if (!SafeReadLink(exe_link, new_path))
return false;
if (my_strcmp(path, new_path) != 0)

47
src/client/linux/minidump_writer/linux_dumper.h
View file

@ -27,6 +27,14 @@
// (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_
@ -121,15 +129,18 @@ class LinuxDumper {
virtual ~LinuxDumper();
// Parse the data for |threads| and |mappings|.
bool Init();
virtual bool Init();
// Return true if the dumper performs a post-mortem dump.
virtual bool IsPostMortem() const = 0;
// Suspend/resume all threads in the given process.
bool ThreadsSuspend();
bool ThreadsResume();
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);
virtual bool GetThreadInfoByIndex(size_t index, ThreadInfo* info) = 0;
// These are only valid after a call to |Init|.
const wasteful_vector<pid_t> &threads() { return threads_; }
@ -146,13 +157,14 @@ class LinuxDumper {
// Copy content of |length| bytes from a given process |child|,
// starting from |src|, into |dest|.
void CopyFromProcess(void* dest, pid_t child, const void* src,
size_t length);
virtual void CopyFromProcess(void* dest, pid_t child, const void* src,
size_t length) = 0;
// Builds a proc path for a certain pid for a node. path is a
// character array that is overwritten, and node is the final node
// without any slashes.
void BuildProcPath(char* path, pid_t pid, const char* node) const;
// 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.
@ -179,9 +191,10 @@ class LinuxDumper {
pid_t crash_thread() const { return crash_thread_; }
void set_crash_thread(pid_t crash_thread) { crash_thread_ = crash_thread; }
private:
bool EnumerateMappings();
bool EnumerateThreads();
protected:
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
@ -208,9 +221,11 @@ class LinuxDumper {
mutable PageAllocator allocator_;
bool threads_suspended_;
wasteful_vector<pid_t> threads_; // the ids of all the threads
wasteful_vector<MappingInfo*> mappings_; // info from /proc/<pid>/maps
// IDs of all the threads.
wasteful_vector<pid_t> threads_;
// Info from /proc/<pid>/maps.
wasteful_vector<MappingInfo*> mappings_;
};
} // namespace google_breakpad

292
src/client/linux/minidump_writer/linux_ptrace_dumper.cc Normal file
View file

@ -0,0 +1,292 @@
// Copyright (c) 2012, 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_ptrace_dumper.cc: Implement google_breakpad::LinuxPtraceDumper.
// See linux_ptrace_dumper.h for detals.
// This class was originally splitted from google_breakpad::LinuxDumper.
// This code deals with the mechanics of getting information about a crashed
// process. Since this code may run in a compromised address space, the same
// rules apply as detailed at the top of minidump_writer.h: no libc calls and
// use the alternative allocator.
#include "client/linux/minidump_writer/linux_ptrace_dumper.h"
#include <asm/ptrace.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include "client/linux/minidump_writer/directory_reader.h"
#include "client/linux/minidump_writer/line_reader.h"
#include "common/linux/linux_libc_support.h"
#include "third_party/lss/linux_syscall_support.h"
// Suspends a thread by attaching to it.
static bool SuspendThread(pid_t pid) {
// This may fail if the thread has just died or debugged.
errno = 0;
if (sys_ptrace(PTRACE_ATTACH, pid, NULL, NULL) != 0 &&
errno != 0) {
return false;
}
while (sys_waitpid(pid, NULL, __WALL) < 0) {
if (errno != EINTR) {
sys_ptrace(PTRACE_DETACH, pid, NULL, NULL);
return false;
}
}
#if defined(__i386) || defined(__x86_64)
// On x86, the stack pointer is NULL or -1, when executing trusted code in
// the seccomp sandbox. Not only does this cause difficulties down the line
// when trying to dump the thread's stack, it also results in the minidumps
// containing information about the trusted threads. This information is
// generally completely meaningless and just pollutes the minidumps.
// We thus test the stack pointer and exclude any threads that are part of
// the seccomp sandbox's trusted code.
user_regs_struct regs;
if (sys_ptrace(PTRACE_GETREGS, pid, NULL, &regs) == -1 ||
#if defined(__i386)
!regs.esp
#elif defined(__x86_64)
!regs.rsp
#endif
) {
sys_ptrace(PTRACE_DETACH, pid, NULL, NULL);
return false;
}
#endif
return true;
}
// Resumes a thread by detaching from it.
static bool ResumeThread(pid_t pid) {
return sys_ptrace(PTRACE_DETACH, pid, NULL, NULL) >= 0;
}
namespace google_breakpad {
LinuxPtraceDumper::LinuxPtraceDumper(pid_t pid)
: LinuxDumper(pid),
threads_suspended_(false) {
}
bool LinuxPtraceDumper::BuildProcPath(char* path, pid_t pid,
const char* node) const {
if (!path || !node || pid <= 0)
return false;
size_t node_len = my_strlen(node);
if (node_len == 0)
return false;
const unsigned pid_len = my_int_len(pid);
const size_t total_length = 6 + pid_len + 1 + node_len;
if (total_length >= NAME_MAX)
return false;
memcpy(path, "/proc/", 6);
my_itos(path + 6, pid, pid_len);
path[6 + pid_len] = '/';
memcpy(path + 6 + pid_len + 1, node, node_len);
path[total_length] = '\0';
return true;
}
void LinuxPtraceDumper::CopyFromProcess(void* dest, pid_t child,
const void* src, size_t length) {
unsigned long tmp = 55;
size_t done = 0;
static const size_t word_size = sizeof(tmp);
uint8_t* const local = (uint8_t*) dest;
uint8_t* const remote = (uint8_t*) src;
while (done < length) {
const size_t l = (length - done > word_size) ? word_size : (length - done);
if (sys_ptrace(PTRACE_PEEKDATA, child, remote + done, &tmp) == -1) {
tmp = 0;
}
memcpy(local + done, &tmp, l);
done += l;
}
}
// Read thread info from /proc/$pid/status.
// Fill out the |tgid|, |ppid| and |pid| members of |info|. If unavailable,
// these members are set to -1. Returns true iff all three members are
// available.
bool LinuxPtraceDumper::GetThreadInfoByIndex(size_t index, ThreadInfo* info) {
if (index >= threads_.size())
return false;
pid_t tid = threads_[index];
assert(info != NULL);
char status_path[NAME_MAX];
if (!BuildProcPath(status_path, tid, "status"))
return false;
const int fd = sys_open(status_path, O_RDONLY, 0);
if (fd < 0)
return false;
LineReader* const line_reader = new(allocator_) LineReader(fd);
const char* line;
unsigned line_len;
info->ppid = info->tgid = -1;
while (line_reader->GetNextLine(&line, &line_len)) {
if (my_strncmp("Tgid:\t", line, 6) == 0) {
my_strtoui(&info->tgid, line + 6);
} else if (my_strncmp("PPid:\t", line, 6) == 0) {
my_strtoui(&info->ppid, line + 6);
}
line_reader->PopLine(line_len);
}
if (info->ppid == -1 || info->tgid == -1)
return false;
if (sys_ptrace(PTRACE_GETREGS, tid, NULL, &info->regs) == -1) {
return false;
}
#if !defined(__ANDROID__)
if (sys_ptrace(PTRACE_GETFPREGS, tid, NULL, &info->fpregs) == -1) {
return false;
}
#endif
#if defined(__i386)
if (sys_ptrace(PTRACE_GETFPXREGS, tid, NULL, &info->fpxregs) == -1)
return false;
#endif
#if defined(__i386) || defined(__x86_64)
for (unsigned i = 0; i < ThreadInfo::kNumDebugRegisters; ++i) {
if (sys_ptrace(
PTRACE_PEEKUSER, tid,
reinterpret_cast<void*> (offsetof(struct user,
u_debugreg[0]) + i *
sizeof(debugreg_t)),
&info->dregs[i]) == -1) {
return false;
}
}
#endif
const uint8_t* stack_pointer;
#if defined(__i386)
memcpy(&stack_pointer, &info->regs.esp, sizeof(info->regs.esp));
#elif defined(__x86_64)
memcpy(&stack_pointer, &info->regs.rsp, sizeof(info->regs.rsp));
#elif defined(__ARM_EABI__)
memcpy(&stack_pointer, &info->regs.ARM_sp, sizeof(info->regs.ARM_sp));
#else
#error "This code hasn't been ported to your platform yet."
#endif
return GetStackInfo(&info->stack, &info->stack_len,
(uintptr_t) stack_pointer);
}
bool LinuxPtraceDumper::IsPostMortem() const {
return false;
}
bool LinuxPtraceDumper::ThreadsSuspend() {
if (threads_suspended_)
return true;
for (size_t i = 0; i < threads_.size(); ++i) {
if (!SuspendThread(threads_[i])) {
// If the thread either disappeared before we could attach to it, or if
// it was part of the seccomp sandbox's trusted code, it is OK to
// silently drop it from the minidump.
memmove(&threads_[i], &threads_[i+1],
(threads_.size() - i - 1) * sizeof(threads_[i]));
threads_.resize(threads_.size() - 1);
--i;
}
}
threads_suspended_ = true;
return threads_.size() > 0;
}
bool LinuxPtraceDumper::ThreadsResume() {
if (!threads_suspended_)
return false;
bool good = true;
for (size_t i = 0; i < threads_.size(); ++i)
good &= ResumeThread(threads_[i]);
threads_suspended_ = false;
return good;
}
// Parse /proc/$pid/task to list all the threads of the process identified by
// pid.
bool LinuxPtraceDumper::EnumerateThreads() {
char task_path[NAME_MAX];
if (!BuildProcPath(task_path, pid_, "task"))
return false;
const int fd = sys_open(task_path, O_RDONLY | O_DIRECTORY, 0);
if (fd < 0)
return false;
DirectoryReader* dir_reader = new(allocator_) DirectoryReader(fd);
// The directory may contain duplicate entries which we filter by assuming
// that they are consecutive.
int last_tid = -1;
const char* dent_name;
while (dir_reader->GetNextEntry(&dent_name)) {
if (my_strcmp(dent_name, ".") &&
my_strcmp(dent_name, "..")) {
int tid = 0;
if (my_strtoui(&tid, dent_name) &&
last_tid != tid) {
last_tid = tid;
threads_.push_back(tid);
}
}
dir_reader->PopEntry();
}
sys_close(fd);
return true;
}
} // namespace google_breakpad

92
src/client/linux/minidump_writer/linux_ptrace_dumper.h Normal file
View file

@ -0,0 +1,92 @@
// Copyright (c) 2012, 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_ptrace_dumper.h: Define the google_breakpad::LinuxPtraceDumper
// class, which is derived from google_breakpad::LinuxDumper to extract
// information from a crashed process via ptrace.
// This class was originally splitted from google_breakpad::LinuxDumper.
#ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINUX_PTRACE_DUMPER_H_
#define CLIENT_LINUX_MINIDUMP_WRITER_LINUX_PTRACE_DUMPER_H_
#include "client/linux/minidump_writer/linux_dumper.h"
namespace google_breakpad {
class LinuxPtraceDumper : public LinuxDumper {
public:
// Constructs a dumper for extracting information of a given process
// with a process ID of |pid|.
explicit LinuxPtraceDumper(pid_t pid);
// Implements LinuxDumper::BuildProcPath().
// 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;
// Implements LinuxDumper::CopyFromProcess().
// Copies content of |length| bytes from a given process |child|,
// starting from |src|, into |dest|. This method uses ptrace to extract
// the content from the target process.
virtual void CopyFromProcess(void* dest, pid_t child, const void* src,
size_t length);
// Implements LinuxDumper::GetThreadInfoByIndex().
// Reads 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);
// Implements LinuxDumper::IsPostMortem().
// Always returns false to indicate this dumper performs a dump of
// a crashed process via ptrace.
virtual bool IsPostMortem() const;
// Implements LinuxDumper::ThreadsSuspend().
// Suspends all threads in the given process. Returns true on success.
virtual bool ThreadsSuspend();
// Implements LinuxDumper::ThreadsResume().
// Resumes all threads in the given process. Returns true on success.
virtual bool ThreadsResume();
protected:
// Implements LinuxDumper::EnumerateThreads().
// Enumerates all threads of the given process into |threads_|.
virtual bool EnumerateThreads();
private:
// Set to true if all threads of the crashed process are suspended.
bool threads_suspended_;
};
} // namespace google_breakpad
#endif // CLIENT_LINUX_HANDLER_LINUX_PTRACE_DUMPER_H_

114
src/client/linux/minidump_writer/linux_dumper_unittest.cc → src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
View file

@ -27,7 +27,11 @@
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <string>
// linux_ptrace_dumper_unittest.cc:
// Unit tests for google_breakpad::LinuxPtraceDumoer.
//
// This file was renamed from linux_dumper_unittest.cc and modified due
// to LinuxDumper being splitted into two classes.
#include <fcntl.h>
#include <limits.h>
@ -39,8 +43,10 @@
#include <sys/stat.h>
#include <sys/types.h>
#include <string>
#include "breakpad_googletest_includes.h"
#include "client/linux/minidump_writer/linux_dumper.h"
#include "client/linux/minidump_writer/linux_ptrace_dumper.h"
#include "common/linux/eintr_wrapper.h"
#include "common/linux/file_id.h"
#include "common/linux/safe_readlink.h"
@ -50,7 +56,8 @@ using std::string;
using namespace google_breakpad;
namespace {
typedef testing::Test LinuxDumperTest;
typedef testing::Test LinuxPtraceDumperTest;
string GetHelperBinary() {
// Locate helper binary next to the current binary.
@ -69,14 +76,14 @@ string GetHelperBinary() {
return helper_path;
}
} // namespace
TEST(LinuxPtraceDumperTest, Setup) {
LinuxPtraceDumper dumper(getpid());
}
TEST(LinuxDumperTest, Setup) {
LinuxDumper dumper(getpid());
}
TEST(LinuxDumperTest, FindMappings) {
LinuxDumper dumper(getpid());
TEST(LinuxPtraceDumperTest, FindMappings) {
LinuxPtraceDumper dumper(getpid());
ASSERT_TRUE(dumper.Init());
ASSERT_TRUE(dumper.FindMapping(reinterpret_cast<void*>(getpid)));
@ -84,8 +91,8 @@ TEST(LinuxDumperTest, FindMappings) {
ASSERT_FALSE(dumper.FindMapping(NULL));
}
TEST(LinuxDumperTest, ThreadList) {
LinuxDumper dumper(getpid());
TEST(LinuxPtraceDumperTest, ThreadList) {
LinuxPtraceDumper dumper(getpid());
ASSERT_TRUE(dumper.Init());
ASSERT_GE(dumper.threads().size(), (size_t)1);
@ -101,7 +108,7 @@ TEST(LinuxDumperTest, ThreadList) {
// Helper stack class to close a file descriptor and unmap
// a mmap'ed mapping.
class StackHelper {
public:
public:
StackHelper(int fd, char* mapping, size_t size)
: fd_(fd), mapping_(mapping), size_(size) {}
~StackHelper() {
@ -109,13 +116,13 @@ public:
close(fd_);
}
private:
private:
int fd_;
char* mapping_;
size_t size_;
};
TEST(LinuxDumperTest, MergedMappings) {
TEST(LinuxPtraceDumperTest, MergedMappings) {
string helper_path(GetHelperBinary());
if (helper_path.empty()) {
FAIL() << "Couldn't find helper binary";
@ -143,18 +150,19 @@ TEST(LinuxDumperTest, MergedMappings) {
StackHelper helper(fd, mapping, kMappingSize);
// Carve a page out of the first mapping with different permissions.
char* inside_mapping = reinterpret_cast<char*>(mmap(mapping + 2 *kPageSize,
kPageSize,
PROT_NONE,
MAP_SHARED | MAP_FIXED,
fd,
// Map a different offset just to
// better test real-world conditions.
kPageSize));
char* inside_mapping = reinterpret_cast<char*>(
mmap(mapping + 2 *kPageSize,
kPageSize,
PROT_NONE,
MAP_SHARED | MAP_FIXED,
fd,
// Map a different offset just to
// better test real-world conditions.
kPageSize));
ASSERT_TRUE(inside_mapping);
// Now check that LinuxDumper interpreted the mappings properly.
LinuxDumper dumper(getpid());
// Now check that LinuxPtraceDumper interpreted the mappings properly.
LinuxPtraceDumper dumper(getpid());
ASSERT_TRUE(dumper.Init());
int mapping_count = 0;
for (unsigned i = 0; i < dumper.mappings().size(); ++i) {
@ -171,7 +179,7 @@ TEST(LinuxDumperTest, MergedMappings) {
EXPECT_EQ(1, mapping_count);
}
TEST(LinuxDumperTest, VerifyStackReadWithMultipleThreads) {
TEST(LinuxPtraceDumperTest, VerifyStackReadWithMultipleThreads) {
static const int kNumberOfThreadsInHelperProgram = 5;
char kNumberOfThreadsArgument[2];
sprintf(kNumberOfThreadsArgument, "%d", kNumberOfThreadsInHelperProgram);
@ -218,13 +226,13 @@ TEST(LinuxDumperTest, VerifyStackReadWithMultipleThreads) {
close(fds[0]);
// Child is ready now.
LinuxDumper dumper(child_pid);
LinuxPtraceDumper dumper(child_pid);
ASSERT_TRUE(dumper.Init());
EXPECT_EQ((size_t)kNumberOfThreadsInHelperProgram, dumper.threads().size());
EXPECT_TRUE(dumper.ThreadsSuspend());
ThreadInfo one_thread;
for(size_t i = 0; i < dumper.threads().size(); ++i) {
for (size_t i = 0; i < dumper.threads().size(); ++i) {
EXPECT_TRUE(dumper.GetThreadInfoByIndex(i, &one_thread));
// In the helper program, we stored a pointer to the thread id in a
// specific register. Check that we can recover its value.
@ -247,39 +255,33 @@ TEST(LinuxDumperTest, VerifyStackReadWithMultipleThreads) {
kill(child_pid, SIGKILL);
}
TEST(LinuxDumperTest, BuildProcPath) {
TEST(LinuxPtraceDumperTest, BuildProcPath) {
const pid_t pid = getpid();
LinuxDumper dumper(pid);
LinuxPtraceDumper dumper(pid);
char maps_path[256] = "dummymappath";
char maps_path_expected[256];
char maps_path[NAME_MAX] = "";
char maps_path_expected[NAME_MAX];
snprintf(maps_path_expected, sizeof(maps_path_expected),
"/proc/%d/maps", pid);
dumper.BuildProcPath(maps_path, pid, "maps");
ASSERT_STREQ(maps_path, maps_path_expected);
EXPECT_TRUE(dumper.BuildProcPath(maps_path, pid, "maps"));
EXPECT_STREQ(maps_path_expected, maps_path);
// In release mode, we expect BuildProcPath to handle the invalid
// parameters correctly and fill map_path with an empty
// NULL-terminated string.
#ifdef NDEBUG
snprintf(maps_path, sizeof(maps_path), "dummymappath");
dumper.BuildProcPath(maps_path, 0, "maps");
EXPECT_STREQ(maps_path, "");
EXPECT_FALSE(dumper.BuildProcPath(NULL, pid, "maps"));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, 0, "maps"));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, ""));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, NULL));
snprintf(maps_path, sizeof(maps_path), "dummymappath");
dumper.BuildProcPath(maps_path, getpid(), "");
EXPECT_STREQ(maps_path, "");
snprintf(maps_path, sizeof(maps_path), "dummymappath");
dumper.BuildProcPath(maps_path, getpid(), NULL);
EXPECT_STREQ(maps_path, "");
#endif
char long_node[NAME_MAX];
size_t long_node_len = NAME_MAX - strlen("/proc/123") - 1;
memset(long_node, 'a', long_node_len);
long_node[long_node_len] = '\0';
EXPECT_FALSE(dumper.BuildProcPath(maps_path, 123, long_node));
}
#if !defined(__ARM_EABI__)
// Ensure that the linux-gate VDSO is included in the mapping list.
TEST(LinuxDumperTest, MappingsIncludeLinuxGate) {
LinuxDumper dumper(getpid());
TEST(LinuxPtraceDumperTest, MappingsIncludeLinuxGate) {
LinuxPtraceDumper dumper(getpid());
ASSERT_TRUE(dumper.Init());
void* linux_gate_loc = dumper.FindBeginningOfLinuxGateSharedLibrary(getpid());
@ -301,8 +303,8 @@ TEST(LinuxDumperTest, MappingsIncludeLinuxGate) {
}
// Ensure that the linux-gate VDSO can generate a non-zeroed File ID.
TEST(LinuxDumperTest, LinuxGateMappingID) {
LinuxDumper dumper(getpid());
TEST(LinuxPtraceDumperTest, LinuxGateMappingID) {
LinuxPtraceDumper dumper(getpid());
ASSERT_TRUE(dumper.Init());
bool found_linux_gate = false;
@ -329,7 +331,7 @@ TEST(LinuxDumperTest, LinuxGateMappingID) {
// Ensure that the linux-gate VDSO can generate a non-zeroed File ID
// from a child process.
TEST(LinuxDumperTest, LinuxGateMappingIDChild) {
TEST(LinuxPtraceDumperTest, LinuxGateMappingIDChild) {
int fds[2];
ASSERT_NE(-1, pipe(fds));
@ -345,7 +347,7 @@ TEST(LinuxDumperTest, LinuxGateMappingIDChild) {
}
close(fds[0]);
LinuxDumper dumper(child);
LinuxPtraceDumper dumper(child);
ASSERT_TRUE(dumper.Init());
bool found_linux_gate = false;
@ -375,7 +377,7 @@ TEST(LinuxDumperTest, LinuxGateMappingIDChild) {
}
#endif
TEST(LinuxDumperTest, FileIDsMatch) {
TEST(LinuxPtraceDumperTest, FileIDsMatch) {
// Calculate the File ID of our binary using both
// FileID::ElfFileIdentifier and LinuxDumper::ElfFileIdentifierForMapping
// and ensure that we get the same result from both.
@ -397,7 +399,7 @@ TEST(LinuxDumperTest, FileIDsMatch) {
}
close(fds[0]);
LinuxDumper dumper(child);
LinuxPtraceDumper dumper(child);
ASSERT_TRUE(dumper.Init());
const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
bool found_exe = false;

60
src/client/linux/minidump_writer/minidump_writer.cc
View file

@ -74,6 +74,8 @@
#include "client/linux/handler/exception_handler.h"
#include "client/linux/minidump_writer/line_reader.h"
#include "client/linux/minidump_writer/linux_dumper.h"
#include "client/linux/minidump_writer/linux_core_dumper.h"
#include "client/linux/minidump_writer/linux_ptrace_dumper.h"
#include "client/linux/minidump_writer/minidump_extension_linux.h"
#include "common/linux/linux_libc_support.h"
#include "third_party/lss/linux_syscall_support.h"
@ -372,9 +374,9 @@ class MinidumpWriter {
const MappingList& mappings,
LinuxDumper* dumper)
: filename_(filename),
ucontext_(&context->context),
ucontext_(context ? &context->context : NULL),
#if !defined(__ARM_EABI__)
float_state_(&context->float_state),
float_state_(context ? &context->float_state : NULL),
#else
// TODO: fix this after fixing ExceptionHandler
float_state_(NULL),
@ -401,18 +403,25 @@ class MinidumpWriter {
struct r_debug* r_debug = NULL;
uint32_t dynamic_length = 0;
#if !defined(__ANDROID__)
// The Android NDK is missing structure definitions for most of this.
// For now, it's simpler just to skip it.
for (int i = 0;;) {
ElfW(Dyn) dyn;
dynamic_length += sizeof(dyn);
dumper_->CopyFromProcess(&dyn, GetCrashThread(), _DYNAMIC+i++,
sizeof(dyn));
if (dyn.d_tag == DT_DEBUG) {
r_debug = (struct r_debug*)dyn.d_un.d_ptr;
continue;
} else if (dyn.d_tag == DT_NULL) {
break;
// This code assumes the crashing process is the same as this process and
// may hang or take a long time to complete if not so.
// Thus, we skip this code for a post-mortem based dump.
if (!dumper_->IsPostMortem()) {
// The Android NDK is missing structure definitions for most of this.
// For now, it's simpler just to skip it.
for (int i = 0;;) {
ElfW(Dyn) dyn;
dynamic_length += sizeof(dyn);
// NOTE: Use of _DYNAMIC assumes this is the same process as the
// crashing process. This loop will go forever if it's out of bounds.
dumper_->CopyFromProcess(&dyn, GetCrashThread(), _DYNAMIC+i++,
sizeof(dyn));
if (dyn.d_tag == DT_DEBUG) {
r_debug = (struct r_debug*)dyn.d_un.d_ptr;
continue;
} else if (dyn.d_tag == DT_NULL) {
break;
}
}
}
#endif
@ -647,7 +656,8 @@ class MinidumpWriter {
// we used the actual state of the thread we would find it running in the
// signal handler with the alternative stack, which would be deeply
// unhelpful.
if ((pid_t)thread.thread_id == GetCrashThread()) {
if (static_cast<pid_t>(thread.thread_id) == GetCrashThread() &&
!dumper_->IsPostMortem()) {
const void* stack;
size_t stack_len;
if (!dumper_->GetStackInfo(&stack, &stack_len, GetStackPointer()))
@ -736,6 +746,10 @@ class MinidumpWriter {
CPUFillFromThreadInfo(cpu.get(), info);
PopSeccompStackFrame(cpu.get(), thread, stack_copy);
thread.thread_context = cpu.location();
if (dumper_->threads()[i] == GetCrashThread()) {
assert(dumper_->IsPostMortem());
crashing_thread_context_ = cpu.location();
}
}
list.CopyIndexAfterObject(i, &thread, sizeof(thread));
@ -1281,7 +1295,8 @@ class MinidumpWriter {
bool WriteProcFile(MDLocationDescriptor* result, pid_t pid,
const char* filename) {
char buf[NAME_MAX];
dumper_->BuildProcPath(buf, pid, filename);
if (!dumper_->BuildProcPath(buf, pid, filename))
return false;
return WriteFile(result, buf);
}
@ -1312,7 +1327,7 @@ bool WriteMinidump(const char* filename, pid_t crashing_process,
return false;
const ExceptionHandler::CrashContext* context =
reinterpret_cast<const ExceptionHandler::CrashContext*>(blob);
LinuxDumper dumper(crashing_process);
LinuxPtraceDumper dumper(crashing_process);
dumper.set_crash_address(
reinterpret_cast<uintptr_t>(context->siginfo.si_addr));
dumper.set_crash_signal(context->siginfo.si_signo);
@ -1323,4 +1338,15 @@ bool WriteMinidump(const char* filename, pid_t crashing_process,
return writer.Dump();
}
bool WriteMinidumpFromCore(const char* filename,
const char* core_path,
const char* procfs_override) {
MappingList mappings;
LinuxCoreDumper dumper(0, core_path, procfs_override);
MinidumpWriter writer(filename, NULL, mappings, &dumper);
if (!writer.Init())
return false;
return writer.Dump();
}
} // namespace google_breakpad

6
src/client/linux/minidump_writer/minidump_writer.h
View file

@ -62,6 +62,12 @@ bool WriteMinidump(const char* filename, pid_t crashing_process,
const void* blob, size_t blob_size,
const MappingList& mappings);
// Write a minidump to the filesystem. Same as above, but uses the given
// core file and procfs directory to generate the minidump post mortem.
bool WriteMinidumpFromCore(const char* filename,
const char* core_path,
const char* procfs_override);
} // namespace google_breakpad
#endif // CLIENT_LINUX_MINIDUMP_WRITER_MINIDUMP_WRITER_H_