| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/debug/debugger.h" |
| #include "build/build_config.h" |
| |
| #if defined(__LB_SHELL__) |
| #include "lb_platform.h" |
| #endif |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <sys/param.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #include <string> |
| #include <vector> |
| |
| #if !defined(OS_ANDROID) && !defined(OS_NACL) |
| #include <execinfo.h> |
| #endif |
| |
| #if defined(__GLIBCXX__) |
| #include <cxxabi.h> |
| #endif |
| |
| #if defined(OS_MACOSX) |
| #include <AvailabilityMacros.h> |
| #endif |
| |
| #if defined(OS_MACOSX) || defined(OS_BSD) |
| #include <sys/sysctl.h> |
| #endif |
| |
| #if defined(OS_FREEBSD) |
| #include <sys/user.h> |
| #endif |
| |
| #include <ostream> |
| |
| #include "base/basictypes.h" |
| #include "base/logging.h" |
| #include "base/memory/scoped_ptr.h" |
| #include "base/posix/eintr_wrapper.h" |
| #include "base/safe_strerror_posix.h" |
| #include "base/string_piece.h" |
| #include "base/stringprintf.h" |
| |
| #if defined(USE_SYMBOLIZE) |
| #include "base/third_party/symbolize/symbolize.h" |
| #endif |
| |
| #if defined(OS_ANDROID) |
| #include "base/threading/platform_thread.h" |
| #endif |
| |
| namespace base { |
| namespace debug { |
| |
| bool SpawnDebuggerOnProcess(unsigned process_id) { |
| #if OS_ANDROID || OS_NACL || defined(__LB_SHELL__) |
| NOTIMPLEMENTED(); |
| return false; |
| #else |
| const std::string debug_cmd = |
| StringPrintf("xterm -e 'gdb --pid=%u' &", process_id); |
| LOG(WARNING) << "Starting debugger on pid " << process_id |
| << " with command `" << debug_cmd << "`"; |
| int ret = system(debug_cmd.c_str()); |
| if (ret == -1) |
| return false; |
| return true; |
| #endif |
| } |
| |
| #if defined(OS_MACOSX) || defined(OS_BSD) |
| |
| // Based on Apple's recommended method as described in |
| // http://developer.apple.com/qa/qa2004/qa1361.html |
| bool BeingDebugged() { |
| // NOTE: This code MUST be async-signal safe (it's used by in-process |
| // stack dumping signal handler). NO malloc or stdio is allowed here. |
| // |
| // While some code used below may be async-signal unsafe, note how |
| // the result is cached (see |is_set| and |being_debugged| static variables |
| // right below). If this code is properly warmed-up early |
| // in the start-up process, it should be safe to use later. |
| |
| // If the process is sandboxed then we can't use the sysctl, so cache the |
| // value. |
| static bool is_set = false; |
| static bool being_debugged = false; |
| |
| if (is_set) |
| return being_debugged; |
| |
| // Initialize mib, which tells sysctl what info we want. In this case, |
| // we're looking for information about a specific process ID. |
| int mib[] = { |
| CTL_KERN, |
| KERN_PROC, |
| KERN_PROC_PID, |
| getpid() |
| #if defined(OS_OPENBSD) |
| , sizeof(struct kinfo_proc), |
| 0 |
| #endif |
| }; |
| |
| // Caution: struct kinfo_proc is marked __APPLE_API_UNSTABLE. The source and |
| // binary interfaces may change. |
| struct kinfo_proc info; |
| size_t info_size = sizeof(info); |
| |
| #if defined(OS_OPENBSD) |
| if (sysctl(mib, arraysize(mib), NULL, &info_size, NULL, 0) < 0) |
| return -1; |
| |
| mib[5] = (info_size / sizeof(struct kinfo_proc)); |
| #endif |
| |
| int sysctl_result = sysctl(mib, arraysize(mib), &info, &info_size, NULL, 0); |
| DCHECK_EQ(sysctl_result, 0); |
| if (sysctl_result != 0) { |
| is_set = true; |
| being_debugged = false; |
| return being_debugged; |
| } |
| |
| // This process is being debugged if the P_TRACED flag is set. |
| is_set = true; |
| #if defined(OS_FREEBSD) |
| being_debugged = (info.ki_flag & P_TRACED) != 0; |
| #elif defined(OS_BSD) |
| being_debugged = (info.p_flag & P_TRACED) != 0; |
| #else |
| being_debugged = (info.kp_proc.p_flag & P_TRACED) != 0; |
| #endif |
| return being_debugged; |
| } |
| |
| #elif defined(OS_LINUX) || defined(OS_ANDROID) |
| |
| // We can look in /proc/self/status for TracerPid. We are likely used in crash |
| // handling, so we are careful not to use the heap or have side effects. |
| // Another option that is common is to try to ptrace yourself, but then we |
| // can't detach without forking(), and that's not so great. |
| // static |
| bool BeingDebugged() { |
| // NOTE: This code MUST be async-signal safe (it's used by in-process |
| // stack dumping signal handler). NO malloc or stdio is allowed here. |
| |
| int status_fd = open("/proc/self/status", O_RDONLY); |
| if (status_fd == -1) |
| return false; |
| |
| // We assume our line will be in the first 1024 characters and that we can |
| // read this much all at once. In practice this will generally be true. |
| // This simplifies and speeds up things considerably. |
| char buf[1024]; |
| |
| ssize_t num_read = HANDLE_EINTR(read(status_fd, buf, sizeof(buf))); |
| if (HANDLE_EINTR(close(status_fd)) < 0) |
| return false; |
| |
| if (num_read <= 0) |
| return false; |
| |
| StringPiece status(buf, num_read); |
| StringPiece tracer("TracerPid:\t"); |
| |
| StringPiece::size_type pid_index = status.find(tracer); |
| if (pid_index == StringPiece::npos) |
| return false; |
| |
| // Our pid is 0 without a debugger, assume this for any pid starting with 0. |
| pid_index += tracer.size(); |
| return pid_index < status.size() && status[pid_index] != '0'; |
| } |
| |
| #elif defined(__LB_SHELL__) |
| |
| bool BeingDebugged() { |
| return LB::Platform::BeingDebugged(); |
| } |
| |
| #else |
| |
| bool BeingDebugged() { |
| NOTIMPLEMENTED(); |
| return false; |
| } |
| |
| #endif |
| |
| // We want to break into the debugger in Debug mode, and cause a crash dump in |
| // Release mode. Breakpad behaves as follows: |
| // |
| // +-------+-----------------+-----------------+ |
| // | OS | Dump on SIGTRAP | Dump on SIGABRT | |
| // +-------+-----------------+-----------------+ |
| // | Linux | N | Y | |
| // | Mac | Y | N | |
| // +-------+-----------------+-----------------+ |
| // |
| // Thus we do the following: |
| // Linux: Debug mode, send SIGTRAP; Release mode, send SIGABRT. |
| // Mac: Always send SIGTRAP. |
| |
| #if defined(__LB_SHELL__) |
| #define DEBUG_BREAK() LB::Platform::DEBUG_BREAK() |
| #elif defined(NDEBUG) && !defined(OS_MACOSX) && !defined(OS_ANDROID) |
| #define DEBUG_BREAK() abort() |
| #elif defined(OS_NACL) |
| // The NaCl verifier doesn't let use use int3. For now, we call abort(). We |
| // should ask for advice from some NaCl experts about the optimum thing here. |
| // http://code.google.com/p/nativeclient/issues/detail?id=645 |
| #define DEBUG_BREAK() abort() |
| |
| #elif defined(ARCH_CPU_ARM_FAMILY) |
| #if defined(OS_ANDROID) |
| // Though Android has a "helpful" process called debuggerd to catch native |
| // signals on the general assumption that they are fatal errors. The bkpt |
| // instruction appears to cause SIGBUS which is trapped by debuggerd, and |
| // we've had great difficulty continuing in a debugger once we stop from |
| // SIG triggered by native code. |
| // |
| // Use GDB to set |go| to 1 to resume execution. |
| #define DEBUG_BREAK() do { \ |
| if (!BeingDebugged()) { \ |
| abort(); \ |
| } else { \ |
| volatile int go = 0; \ |
| while (!go) { \ |
| base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(100)); \ |
| } \ |
| } \ |
| } while (0) |
| #else |
| // ARM && !ANDROID |
| #define DEBUG_BREAK() asm("bkpt 0") |
| #endif |
| #elif defined(ARCH_CPU_MIPS_FAMILY) |
| #define DEBUG_BREAK() asm("break 2") |
| #else |
| #define DEBUG_BREAK() asm("int3") |
| #endif |
| |
| void BreakDebugger() { |
| // NOTE: This code MUST be async-signal safe (it's used by in-process |
| // stack dumping signal handler). NO malloc or stdio is allowed here. |
| |
| DEBUG_BREAK(); |
| #if (defined(OS_ANDROID) && !defined(OFFICIAL_BUILD)) || \ |
| (defined(__LB_ANDROID__) && !defined(__LB_SHELL__FOR_RELEASE__)) |
| // For Android development we always build release (debug builds are |
| // unmanageably large), so the unofficial build is used for debugging. It is |
| // helpful to be able to insert BreakDebugger() statements in the source, |
| // attach the debugger, inspect the state of the program and then resume it by |
| // setting the 'go' variable above. |
| #elif defined(NDEBUG) |
| // Terminate the program after signaling the debug break. |
| _exit(1); |
| #endif |
| } |
| |
| } // namespace debug |
| } // namespace base |