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llvm-project/lldb/source/Plugins/Process/FreeBSD/ProcessMonitor.cpp

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//===-- ProcessMonitor.cpp ------------------------------------ -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// C Includes
#include <errno.h>
#include <poll.h>
#include <signal.h>
#include <stdint.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
// C++ Includes
// Other libraries and framework includes
#include "lldb/Core/RegisterValue.h"
#include "lldb/Core/Scalar.h"
#include "lldb/Host/Host.h"
#include "lldb/Host/PseudoTerminal.h"
#include "lldb/Host/ThreadLauncher.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/UnixSignals.h"
#include "lldb/Utility/Status.h"
#include "llvm/Support/Errno.h"
#include "FreeBSDThread.h"
#include "Plugins/Process/POSIX/CrashReason.h"
#include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
#include "ProcessFreeBSD.h"
#include "ProcessMonitor.h"
extern "C" {
extern char **environ;
}
using namespace lldb;
using namespace lldb_private;
// We disable the tracing of ptrace calls for integration builds to
// avoid the additional indirection and checks.
#ifndef LLDB_CONFIGURATION_BUILDANDINTEGRATION
// Wrapper for ptrace to catch errors and log calls.
const char *Get_PT_IO_OP(int op) {
switch (op) {
case PIOD_READ_D:
return "READ_D";
case PIOD_WRITE_D:
return "WRITE_D";
case PIOD_READ_I:
return "READ_I";
case PIOD_WRITE_I:
return "WRITE_I";
default:
return "Unknown op";
}
}
// Wrapper for ptrace to catch errors and log calls.
// Note that ptrace sets errno on error because -1 is reserved as a valid
// result.
extern long PtraceWrapper(int req, lldb::pid_t pid, void *addr, int data,
const char *reqName, const char *file, int line) {
long int result;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PTRACE));
if (log) {
log->Printf("ptrace(%s, %" PRIu64 ", %p, %x) called from file %s line %d",
reqName, pid, addr, data, file, line);
if (req == PT_IO) {
struct ptrace_io_desc *pi = (struct ptrace_io_desc *)addr;
log->Printf("PT_IO: op=%s offs=%zx size=%zu", Get_PT_IO_OP(pi->piod_op),
(size_t)pi->piod_offs, pi->piod_len);
}
}
// PtraceDisplayBytes(req, data);
errno = 0;
result = ptrace(req, pid, (caddr_t)addr, data);
// PtraceDisplayBytes(req, data);
if (log && errno != 0) {
const char *str;
switch (errno) {
case ESRCH:
str = "ESRCH";
break;
case EINVAL:
str = "EINVAL";
break;
case EBUSY:
str = "EBUSY";
break;
case EPERM:
str = "EPERM";
break;
default:
str = "<unknown>";
}
log->Printf("ptrace() failed; errno=%d (%s)", errno, str);
}
if (log) {
#ifdef __amd64__
if (req == PT_GETREGS) {
struct reg *r = (struct reg *)addr;
log->Printf("PT_GETREGS: rip=0x%lx rsp=0x%lx rbp=0x%lx rax=0x%lx",
r->r_rip, r->r_rsp, r->r_rbp, r->r_rax);
}
if (req == PT_GETDBREGS || req == PT_SETDBREGS) {
struct dbreg *r = (struct dbreg *)addr;
char setget = (req == PT_GETDBREGS) ? 'G' : 'S';
for (int i = 0; i <= 7; i++)
log->Printf("PT_%cETDBREGS: dr[%d]=0x%lx", setget, i, r->dr[i]);
}
#endif
}
return result;
}
// Wrapper for ptrace when logging is not required.
// Sets errno to 0 prior to calling ptrace.
extern long PtraceWrapper(int req, lldb::pid_t pid, void *addr, int data) {
long result = 0;
errno = 0;
result = ptrace(req, pid, (caddr_t)addr, data);
return result;
}
#define PTRACE(req, pid, addr, data) \
PtraceWrapper((req), (pid), (addr), (data), #req, __FILE__, __LINE__)
#else
PtraceWrapper((req), (pid), (addr), (data))
#endif
//------------------------------------------------------------------------------
// Static implementations of ProcessMonitor::ReadMemory and
// ProcessMonitor::WriteMemory. This enables mutual recursion between these
// functions without needed to go thru the thread funnel.
static size_t DoReadMemory(lldb::pid_t pid, lldb::addr_t vm_addr, void *buf,
size_t size, Status &error) {
struct ptrace_io_desc pi_desc;
pi_desc.piod_op = PIOD_READ_D;
pi_desc.piod_offs = (void *)vm_addr;
pi_desc.piod_addr = buf;
pi_desc.piod_len = size;
if (PTRACE(PT_IO, pid, (caddr_t)&pi_desc, 0) < 0)
error.SetErrorToErrno();
return pi_desc.piod_len;
}
static size_t DoWriteMemory(lldb::pid_t pid, lldb::addr_t vm_addr,
const void *buf, size_t size, Status &error) {
struct ptrace_io_desc pi_desc;
pi_desc.piod_op = PIOD_WRITE_D;
pi_desc.piod_offs = (void *)vm_addr;
pi_desc.piod_addr = (void *)buf;
pi_desc.piod_len = size;
if (PTRACE(PT_IO, pid, (caddr_t)&pi_desc, 0) < 0)
error.SetErrorToErrno();
return pi_desc.piod_len;
}
// Simple helper function to ensure flags are enabled on the given file
// descriptor.
static bool EnsureFDFlags(int fd, int flags, Status &error) {
int status;
if ((status = fcntl(fd, F_GETFL)) == -1) {
error.SetErrorToErrno();
return false;
}
if (fcntl(fd, F_SETFL, status | flags) == -1) {
error.SetErrorToErrno();
return false;
}
return true;
}
//------------------------------------------------------------------------------
/// @class Operation
/// @brief Represents a ProcessMonitor operation.
///
/// Under FreeBSD, it is not possible to ptrace() from any other thread but the
/// one that spawned or attached to the process from the start. Therefore, when
/// a ProcessMonitor is asked to deliver or change the state of an inferior
/// process the operation must be "funneled" to a specific thread to perform the
/// task. The Operation class provides an abstract base for all services the
/// ProcessMonitor must perform via the single virtual function Execute, thus
/// encapsulating the code that needs to run in the privileged context.
class Operation {
public:
virtual ~Operation() {}
virtual void Execute(ProcessMonitor *monitor) = 0;
};
//------------------------------------------------------------------------------
/// @class ReadOperation
/// @brief Implements ProcessMonitor::ReadMemory.
class ReadOperation : public Operation {
public:
ReadOperation(lldb::addr_t addr, void *buff, size_t size, Status &error,
size_t &result)
: m_addr(addr), m_buff(buff), m_size(size), m_error(error),
m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::addr_t m_addr;
void *m_buff;
size_t m_size;
Status &m_error;
size_t &m_result;
};
void ReadOperation::Execute(ProcessMonitor *monitor) {
lldb::pid_t pid = monitor->GetPID();
m_result = DoReadMemory(pid, m_addr, m_buff, m_size, m_error);
}
//------------------------------------------------------------------------------
/// @class WriteOperation
/// @brief Implements ProcessMonitor::WriteMemory.
class WriteOperation : public Operation {
public:
WriteOperation(lldb::addr_t addr, const void *buff, size_t size,
Status &error, size_t &result)
: m_addr(addr), m_buff(buff), m_size(size), m_error(error),
m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::addr_t m_addr;
const void *m_buff;
size_t m_size;
Status &m_error;
size_t &m_result;
};
void WriteOperation::Execute(ProcessMonitor *monitor) {
lldb::pid_t pid = monitor->GetPID();
m_result = DoWriteMemory(pid, m_addr, m_buff, m_size, m_error);
}
//------------------------------------------------------------------------------
/// @class ReadRegOperation
/// @brief Implements ProcessMonitor::ReadRegisterValue.
class ReadRegOperation : public Operation {
public:
ReadRegOperation(lldb::tid_t tid, unsigned offset, unsigned size,
RegisterValue &value, bool &result)
: m_tid(tid), m_offset(offset), m_size(size), m_value(value),
m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
unsigned m_offset;
unsigned m_size;
RegisterValue &m_value;
bool &m_result;
};
void ReadRegOperation::Execute(ProcessMonitor *monitor) {
struct reg regs;
int rc;
if ((rc = PTRACE(PT_GETREGS, m_tid, (caddr_t)&regs, 0)) < 0) {
m_result = false;
} else {
// 'struct reg' contains only 32- or 64-bit register values. Punt on
// others. Also, not all entries may be uintptr_t sized, such as 32-bit
// processes on powerpc64 (probably the same for i386 on amd64)
if (m_size == sizeof(uint32_t))
m_value = *(uint32_t *)(((caddr_t)&regs) + m_offset);
else if (m_size == sizeof(uint64_t))
m_value = *(uint64_t *)(((caddr_t)&regs) + m_offset);
else
memcpy((void *)&m_value, (((caddr_t)&regs) + m_offset), m_size);
m_result = true;
}
}
//------------------------------------------------------------------------------
/// @class WriteRegOperation
/// @brief Implements ProcessMonitor::WriteRegisterValue.
class WriteRegOperation : public Operation {
public:
WriteRegOperation(lldb::tid_t tid, unsigned offset,
const RegisterValue &value, bool &result)
: m_tid(tid), m_offset(offset), m_value(value), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
unsigned m_offset;
const RegisterValue &m_value;
bool &m_result;
};
void WriteRegOperation::Execute(ProcessMonitor *monitor) {
struct reg regs;
if (PTRACE(PT_GETREGS, m_tid, (caddr_t)&regs, 0) < 0) {
m_result = false;
return;
}
*(uintptr_t *)(((caddr_t)&regs) + m_offset) =
(uintptr_t)m_value.GetAsUInt64();
if (PTRACE(PT_SETREGS, m_tid, (caddr_t)&regs, 0) < 0)
m_result = false;
else
m_result = true;
}
//------------------------------------------------------------------------------
/// @class ReadDebugRegOperation
/// @brief Implements ProcessMonitor::ReadDebugRegisterValue.
class ReadDebugRegOperation : public Operation {
public:
ReadDebugRegOperation(lldb::tid_t tid, unsigned offset, unsigned size,
RegisterValue &value, bool &result)
: m_tid(tid), m_offset(offset), m_size(size), m_value(value),
m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
unsigned m_offset;
unsigned m_size;
RegisterValue &m_value;
bool &m_result;
};
void ReadDebugRegOperation::Execute(ProcessMonitor *monitor) {
struct dbreg regs;
int rc;
if ((rc = PTRACE(PT_GETDBREGS, m_tid, (caddr_t)&regs, 0)) < 0) {
m_result = false;
} else {
if (m_size == sizeof(uintptr_t))
m_value = *(uintptr_t *)(((caddr_t)&regs) + m_offset);
else
memcpy((void *)&m_value, (((caddr_t)&regs) + m_offset), m_size);
m_result = true;
}
}
//------------------------------------------------------------------------------
/// @class WriteDebugRegOperation
/// @brief Implements ProcessMonitor::WriteDebugRegisterValue.
class WriteDebugRegOperation : public Operation {
public:
WriteDebugRegOperation(lldb::tid_t tid, unsigned offset,
const RegisterValue &value, bool &result)
: m_tid(tid), m_offset(offset), m_value(value), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
unsigned m_offset;
const RegisterValue &m_value;
bool &m_result;
};
void WriteDebugRegOperation::Execute(ProcessMonitor *monitor) {
struct dbreg regs;
if (PTRACE(PT_GETDBREGS, m_tid, (caddr_t)&regs, 0) < 0) {
m_result = false;
return;
}
*(uintptr_t *)(((caddr_t)&regs) + m_offset) =
(uintptr_t)m_value.GetAsUInt64();
if (PTRACE(PT_SETDBREGS, m_tid, (caddr_t)&regs, 0) < 0)
m_result = false;
else
m_result = true;
}
//------------------------------------------------------------------------------
/// @class ReadGPROperation
/// @brief Implements ProcessMonitor::ReadGPR.
class ReadGPROperation : public Operation {
public:
ReadGPROperation(lldb::tid_t tid, void *buf, bool &result)
: m_tid(tid), m_buf(buf), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
void *m_buf;
bool &m_result;
};
void ReadGPROperation::Execute(ProcessMonitor *monitor) {
int rc;
errno = 0;
rc = PTRACE(PT_GETREGS, m_tid, (caddr_t)m_buf, 0);
if (errno != 0)
m_result = false;
else
m_result = true;
}
//------------------------------------------------------------------------------
/// @class ReadFPROperation
/// @brief Implements ProcessMonitor::ReadFPR.
class ReadFPROperation : public Operation {
public:
ReadFPROperation(lldb::tid_t tid, void *buf, bool &result)
: m_tid(tid), m_buf(buf), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
void *m_buf;
bool &m_result;
};
void ReadFPROperation::Execute(ProcessMonitor *monitor) {
if (PTRACE(PT_GETFPREGS, m_tid, (caddr_t)m_buf, 0) < 0)
m_result = false;
else
m_result = true;
}
//------------------------------------------------------------------------------
/// @class WriteGPROperation
/// @brief Implements ProcessMonitor::WriteGPR.
class WriteGPROperation : public Operation {
public:
WriteGPROperation(lldb::tid_t tid, void *buf, bool &result)
: m_tid(tid), m_buf(buf), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
void *m_buf;
bool &m_result;
};
void WriteGPROperation::Execute(ProcessMonitor *monitor) {
if (PTRACE(PT_SETREGS, m_tid, (caddr_t)m_buf, 0) < 0)
m_result = false;
else
m_result = true;
}
//------------------------------------------------------------------------------
/// @class WriteFPROperation
/// @brief Implements ProcessMonitor::WriteFPR.
class WriteFPROperation : public Operation {
public:
WriteFPROperation(lldb::tid_t tid, void *buf, bool &result)
: m_tid(tid), m_buf(buf), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
void *m_buf;
bool &m_result;
};
void WriteFPROperation::Execute(ProcessMonitor *monitor) {
if (PTRACE(PT_SETFPREGS, m_tid, (caddr_t)m_buf, 0) < 0)
m_result = false;
else
m_result = true;
}
//------------------------------------------------------------------------------
/// @class ResumeOperation
/// @brief Implements ProcessMonitor::Resume.
class ResumeOperation : public Operation {
public:
ResumeOperation(uint32_t signo, bool &result)
: m_signo(signo), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
uint32_t m_signo;
bool &m_result;
};
void ResumeOperation::Execute(ProcessMonitor *monitor) {
lldb::pid_t pid = monitor->GetPID();
int data = 0;
if (m_signo != LLDB_INVALID_SIGNAL_NUMBER)
data = m_signo;
if (PTRACE(PT_CONTINUE, pid, (caddr_t)1, data)) {
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
LLDB_LOG(log, "ResumeOperation ({0}) failed: {1}", pid,
llvm::sys::StrError(errno));
m_result = false;
} else
m_result = true;
}
//------------------------------------------------------------------------------
/// @class SingleStepOperation
/// @brief Implements ProcessMonitor::SingleStep.
class SingleStepOperation : public Operation {
public:
SingleStepOperation(uint32_t signo, bool &result)
: m_signo(signo), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
uint32_t m_signo;
bool &m_result;
};
void SingleStepOperation::Execute(ProcessMonitor *monitor) {
lldb::pid_t pid = monitor->GetPID();
int data = 0;
if (m_signo != LLDB_INVALID_SIGNAL_NUMBER)
data = m_signo;
if (PTRACE(PT_STEP, pid, NULL, data))
m_result = false;
else
m_result = true;
}
//------------------------------------------------------------------------------
/// @class LwpInfoOperation
/// @brief Implements ProcessMonitor::GetLwpInfo.
class LwpInfoOperation : public Operation {
public:
LwpInfoOperation(lldb::tid_t tid, void *info, bool &result, int &ptrace_err)
: m_tid(tid), m_info(info), m_result(result), m_err(ptrace_err) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
void *m_info;
bool &m_result;
int &m_err;
};
void LwpInfoOperation::Execute(ProcessMonitor *monitor) {
struct ptrace_lwpinfo plwp;
if (PTRACE(PT_LWPINFO, m_tid, (caddr_t)&plwp, sizeof(plwp))) {
m_result = false;
m_err = errno;
} else {
memcpy(m_info, &plwp, sizeof(plwp));
m_result = true;
}
}
//------------------------------------------------------------------------------
/// @class ThreadSuspendOperation
/// @brief Implements ProcessMonitor::ThreadSuspend.
class ThreadSuspendOperation : public Operation {
public:
ThreadSuspendOperation(lldb::tid_t tid, bool suspend, bool &result)
: m_tid(tid), m_suspend(suspend), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
bool m_suspend;
bool &m_result;
};
void ThreadSuspendOperation::Execute(ProcessMonitor *monitor) {
m_result = !PTRACE(m_suspend ? PT_SUSPEND : PT_RESUME, m_tid, NULL, 0);
}
//------------------------------------------------------------------------------
/// @class EventMessageOperation
/// @brief Implements ProcessMonitor::GetEventMessage.
class EventMessageOperation : public Operation {
public:
EventMessageOperation(lldb::tid_t tid, unsigned long *message, bool &result)
: m_tid(tid), m_message(message), m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
lldb::tid_t m_tid;
unsigned long *m_message;
bool &m_result;
};
void EventMessageOperation::Execute(ProcessMonitor *monitor) {
struct ptrace_lwpinfo plwp;
if (PTRACE(PT_LWPINFO, m_tid, (caddr_t)&plwp, sizeof(plwp)))
m_result = false;
else {
if (plwp.pl_flags & PL_FLAG_FORKED) {
*m_message = plwp.pl_child_pid;
m_result = true;
} else
m_result = false;
}
}
//------------------------------------------------------------------------------
/// @class KillOperation
/// @brief Implements ProcessMonitor::Kill.
class KillOperation : public Operation {
public:
KillOperation(bool &result) : m_result(result) {}
void Execute(ProcessMonitor *monitor);
private:
bool &m_result;
};
void KillOperation::Execute(ProcessMonitor *monitor) {
lldb::pid_t pid = monitor->GetPID();
if (PTRACE(PT_KILL, pid, NULL, 0))
m_result = false;
else
m_result = true;
}
//------------------------------------------------------------------------------
/// @class DetachOperation
/// @brief Implements ProcessMonitor::Detach.
class DetachOperation : public Operation {
public:
DetachOperation(Status &result) : m_error(result) {}
void Execute(ProcessMonitor *monitor);
private:
Status &m_error;
};
void DetachOperation::Execute(ProcessMonitor *monitor) {
lldb::pid_t pid = monitor->GetPID();
if (PTRACE(PT_DETACH, pid, NULL, 0) < 0)
m_error.SetErrorToErrno();
}
ProcessMonitor::OperationArgs::OperationArgs(ProcessMonitor *monitor)
: m_monitor(monitor) {
sem_init(&m_semaphore, 0, 0);
}
ProcessMonitor::OperationArgs::~OperationArgs() { sem_destroy(&m_semaphore); }
ProcessMonitor::LaunchArgs::LaunchArgs(ProcessMonitor *monitor,
lldb_private::Module *module,
char const **argv, char const **envp,
const FileSpec &stdin_file_spec,
const FileSpec &stdout_file_spec,
const FileSpec &stderr_file_spec,
const FileSpec &working_dir)
: OperationArgs(monitor), m_module(module), m_argv(argv), m_envp(envp),
m_stdin_file_spec(stdin_file_spec), m_stdout_file_spec(stdout_file_spec),
m_stderr_file_spec(stderr_file_spec), m_working_dir(working_dir) {}
ProcessMonitor::LaunchArgs::~LaunchArgs() {}
ProcessMonitor::AttachArgs::AttachArgs(ProcessMonitor *monitor, lldb::pid_t pid)
: OperationArgs(monitor), m_pid(pid) {}
ProcessMonitor::AttachArgs::~AttachArgs() {}
//------------------------------------------------------------------------------
/// The basic design of the ProcessMonitor is built around two threads.
///
/// One thread (@see SignalThread) simply blocks on a call to waitpid() looking
/// for changes in the debugee state. When a change is detected a
/// ProcessMessage is sent to the associated ProcessFreeBSD instance. This
/// thread
/// "drives" state changes in the debugger.
///
/// The second thread (@see OperationThread) is responsible for two things 1)
/// launching or attaching to the inferior process, and then 2) servicing
/// operations such as register reads/writes, stepping, etc. See the comments
/// on the Operation class for more info as to why this is needed.
ProcessMonitor::ProcessMonitor(
ProcessFreeBSD *process, Module *module, const char *argv[],
const char *envp[], const FileSpec &stdin_file_spec,
const FileSpec &stdout_file_spec, const FileSpec &stderr_file_spec,
const FileSpec &working_dir,
const lldb_private::ProcessLaunchInfo & /* launch_info */,
lldb_private::Status &error)
: m_process(static_cast<ProcessFreeBSD *>(process)),
m_pid(LLDB_INVALID_PROCESS_ID), m_terminal_fd(-1), m_operation(0) {
using namespace std::placeholders;
std::unique_ptr<LaunchArgs> args(
new LaunchArgs(this, module, argv, envp, stdin_file_spec,
stdout_file_spec, stderr_file_spec, working_dir));
sem_init(&m_operation_pending, 0, 0);
sem_init(&m_operation_done, 0, 0);
StartLaunchOpThread(args.get(), error);
if (!error.Success())
return;
if (llvm::sys::RetryAfterSignal(-1, sem_wait, &args->m_semaphore) == -1) {
error.SetErrorToErrno();
return;
}
// Check that the launch was a success.
if (!args->m_error.Success()) {
StopOpThread();
error = args->m_error;
return;
}
// Finally, start monitoring the child process for change in state.
m_monitor_thread = Host::StartMonitoringChildProcess(
std::bind(&ProcessMonitor::MonitorCallback, this, _1, _2, _3, _4),
GetPID(), true);
if (!m_monitor_thread.IsJoinable()) {
error.SetErrorToGenericError();
error.SetErrorString("Process launch failed.");
return;
}
}
ProcessMonitor::ProcessMonitor(ProcessFreeBSD *process, lldb::pid_t pid,
lldb_private::Status &error)
: m_process(static_cast<ProcessFreeBSD *>(process)), m_pid(pid),
m_terminal_fd(-1), m_operation(0) {
using namespace std::placeholders;
sem_init(&m_operation_pending, 0, 0);
sem_init(&m_operation_done, 0, 0);
std::unique_ptr<AttachArgs> args(new AttachArgs(this, pid));
StartAttachOpThread(args.get(), error);
if (!error.Success())
return;
if (llvm::sys::RetryAfterSignal(-1, sem_wait, &args->m_semaphore) == -1) {
error.SetErrorToErrno();
return;
}
// Check that the attach was a success.
if (!args->m_error.Success()) {
StopOpThread();
error = args->m_error;
return;
}
// Finally, start monitoring the child process for change in state.
m_monitor_thread = Host::StartMonitoringChildProcess(
std::bind(&ProcessMonitor::MonitorCallback, this, _1, _2, _3, _4),
GetPID(), true);
if (!m_monitor_thread.IsJoinable()) {
error.SetErrorToGenericError();
error.SetErrorString("Process attach failed.");
return;
}
}
ProcessMonitor::~ProcessMonitor() { StopMonitor(); }
//------------------------------------------------------------------------------
// Thread setup and tear down.
void ProcessMonitor::StartLaunchOpThread(LaunchArgs *args, Status &error) {
static const char *g_thread_name = "lldb.process.freebsd.operation";
if (m_operation_thread.IsJoinable())
return;
m_operation_thread =
ThreadLauncher::LaunchThread(g_thread_name, LaunchOpThread, args, &error);
}
void *ProcessMonitor::LaunchOpThread(void *arg) {
LaunchArgs *args = static_cast<LaunchArgs *>(arg);
if (!Launch(args)) {
sem_post(&args->m_semaphore);
return NULL;
}
ServeOperation(args);
return NULL;
}
bool ProcessMonitor::Launch(LaunchArgs *args) {
ProcessMonitor *monitor = args->m_monitor;
ProcessFreeBSD &process = monitor->GetProcess();
const char **argv = args->m_argv;
const char **envp = args->m_envp;
const FileSpec &stdin_file_spec = args->m_stdin_file_spec;
const FileSpec &stdout_file_spec = args->m_stdout_file_spec;
const FileSpec &stderr_file_spec = args->m_stderr_file_spec;
const FileSpec &working_dir = args->m_working_dir;
lldb_utility::PseudoTerminal terminal;
const size_t err_len = 1024;
char err_str[err_len];
::pid_t pid;
// Propagate the environment if one is not supplied.
if (envp == NULL || envp[0] == NULL)
envp = const_cast<const char **>(environ);
if ((pid = terminal.Fork(err_str, err_len)) == -1) {
args->m_error.SetErrorToGenericError();
args->m_error.SetErrorString("Process fork failed.");
goto FINISH;
}
// Recognized child exit status codes.
enum {
ePtraceFailed = 1,
eDupStdinFailed,
eDupStdoutFailed,
eDupStderrFailed,
eChdirFailed,
eExecFailed,
eSetGidFailed
};
// Child process.
if (pid == 0) {
// Trace this process.
if (PTRACE(PT_TRACE_ME, 0, NULL, 0) < 0)
exit(ePtraceFailed);
// terminal has already dupped the tty descriptors to stdin/out/err.
// This closes original fd from which they were copied (and avoids
// leaking descriptors to the debugged process.
terminal.CloseSlaveFileDescriptor();
// Do not inherit setgid powers.
if (setgid(getgid()) != 0)
exit(eSetGidFailed);
// Let us have our own process group.
setpgid(0, 0);
// Dup file descriptors if needed.
//
// FIXME: If two or more of the paths are the same we needlessly open
// the same file multiple times.
if (stdin_file_spec)
if (!DupDescriptor(stdin_file_spec, STDIN_FILENO, O_RDONLY))
exit(eDupStdinFailed);
if (stdout_file_spec)
if (!DupDescriptor(stdout_file_spec, STDOUT_FILENO, O_WRONLY | O_CREAT))
exit(eDupStdoutFailed);
if (stderr_file_spec)
if (!DupDescriptor(stderr_file_spec, STDERR_FILENO, O_WRONLY | O_CREAT))
exit(eDupStderrFailed);
// Change working directory
if (working_dir && 0 != ::chdir(working_dir.GetCString()))
exit(eChdirFailed);
// Execute. We should never return.
execve(argv[0], const_cast<char *const *>(argv),
const_cast<char *const *>(envp));
exit(eExecFailed);
}
// Wait for the child process to to trap on its call to execve.
::pid_t wpid;
int status;
if ((wpid = waitpid(pid, &status, 0)) < 0) {
args->m_error.SetErrorToErrno();
goto FINISH;
} else if (WIFEXITED(status)) {
// open, dup or execve likely failed for some reason.
args->m_error.SetErrorToGenericError();
switch (WEXITSTATUS(status)) {
case ePtraceFailed:
args->m_error.SetErrorString("Child ptrace failed.");
break;
case eDupStdinFailed:
args->m_error.SetErrorString("Child open stdin failed.");
break;
case eDupStdoutFailed:
args->m_error.SetErrorString("Child open stdout failed.");
break;
case eDupStderrFailed:
args->m_error.SetErrorString("Child open stderr failed.");
break;
case eChdirFailed:
args->m_error.SetErrorString("Child failed to set working directory.");
break;
case eExecFailed:
args->m_error.SetErrorString("Child exec failed.");
break;
case eSetGidFailed:
args->m_error.SetErrorString("Child setgid failed.");
break;
default:
args->m_error.SetErrorString("Child returned unknown exit status.");
break;
}
goto FINISH;
}
assert(WIFSTOPPED(status) && wpid == (::pid_t)pid &&
"Could not sync with inferior process.");
#ifdef notyet
// Have the child raise an event on exit. This is used to keep the child in
// limbo until it is destroyed.
if (PTRACE(PTRACE_SETOPTIONS, pid, NULL, PTRACE_O_TRACEEXIT) < 0) {
args->m_error.SetErrorToErrno();
goto FINISH;
}
#endif
// Release the master terminal descriptor and pass it off to the
// ProcessMonitor instance. Similarly stash the inferior pid.
monitor->m_terminal_fd = terminal.ReleaseMasterFileDescriptor();
monitor->m_pid = pid;
// Set the terminal fd to be in non blocking mode (it simplifies the
// implementation of ProcessFreeBSD::GetSTDOUT to have a non-blocking
// descriptor to read from).
if (!EnsureFDFlags(monitor->m_terminal_fd, O_NONBLOCK, args->m_error))
goto FINISH;
process.SendMessage(ProcessMessage::Attach(pid));
FINISH:
return args->m_error.Success();
}
void ProcessMonitor::StartAttachOpThread(AttachArgs *args,
lldb_private::Status &error) {
static const char *g_thread_name = "lldb.process.freebsd.operation";
if (m_operation_thread.IsJoinable())
return;
m_operation_thread =
ThreadLauncher::LaunchThread(g_thread_name, AttachOpThread, args, &error);
}
void *ProcessMonitor::AttachOpThread(void *arg) {
AttachArgs *args = static_cast<AttachArgs *>(arg);
Attach(args);
ServeOperation(args);
return NULL;
}
void ProcessMonitor::Attach(AttachArgs *args) {
lldb::pid_t pid = args->m_pid;
ProcessMonitor *monitor = args->m_monitor;
ProcessFreeBSD &process = monitor->GetProcess();
if (pid <= 1) {
args->m_error.SetErrorToGenericError();
args->m_error.SetErrorString("Attaching to process 1 is not allowed.");
return;
}
// Attach to the requested process.
if (PTRACE(PT_ATTACH, pid, NULL, 0) < 0) {
args->m_error.SetErrorToErrno();
return;
}
int status;
if ((status = waitpid(pid, NULL, 0)) < 0) {
args->m_error.SetErrorToErrno();
return;
}
process.SendMessage(ProcessMessage::Attach(pid));
}
size_t
ProcessMonitor::GetCurrentThreadIDs(std::vector<lldb::tid_t> &thread_ids) {
lwpid_t *tids;
int tdcnt;
thread_ids.clear();
tdcnt = PTRACE(PT_GETNUMLWPS, m_pid, NULL, 0);
if (tdcnt <= 0)
return 0;
tids = (lwpid_t *)malloc(tdcnt * sizeof(*tids));
if (tids == NULL)
return 0;
if (PTRACE(PT_GETLWPLIST, m_pid, (void *)tids, tdcnt) < 0) {
free(tids);
return 0;
}
thread_ids = std::vector<lldb::tid_t>(tids, tids + tdcnt);
free(tids);
return thread_ids.size();
}
bool ProcessMonitor::MonitorCallback(ProcessMonitor *monitor, lldb::pid_t pid,
bool exited, int signal, int status) {
ProcessMessage message;
ProcessFreeBSD *process = monitor->m_process;
assert(process);
bool stop_monitoring;
struct ptrace_lwpinfo plwp;
int ptrace_err;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
if (exited) {
if (log)
log->Printf("ProcessMonitor::%s() got exit signal, tid = %" PRIu64,
__FUNCTION__, pid);
message = ProcessMessage::Exit(pid, status);
process->SendMessage(message);
return pid == process->GetID();
}
if (!monitor->GetLwpInfo(pid, &plwp, ptrace_err))
stop_monitoring = true; // pid is gone. Bail.
else {
switch (plwp.pl_siginfo.si_signo) {
case SIGTRAP:
message = MonitorSIGTRAP(monitor, &plwp.pl_siginfo, plwp.pl_lwpid);
break;
default:
message = MonitorSignal(monitor, &plwp.pl_siginfo, plwp.pl_lwpid);
break;
}
process->SendMessage(message);
stop_monitoring = message.GetKind() == ProcessMessage::eExitMessage;
}
return stop_monitoring;
}
ProcessMessage ProcessMonitor::MonitorSIGTRAP(ProcessMonitor *monitor,
const siginfo_t *info,
lldb::tid_t tid) {
ProcessMessage message;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
assert(monitor);
assert(info && info->si_signo == SIGTRAP && "Unexpected child signal!");
switch (info->si_code) {
default:
assert(false && "Unexpected SIGTRAP code!");
break;
case (SIGTRAP /* | (PTRACE_EVENT_EXIT << 8) */): {
// The inferior process is about to exit. Maintain the process in a
// state of "limbo" until we are explicitly commanded to detach,
// destroy, resume, etc.
unsigned long data = 0;
if (!monitor->GetEventMessage(tid, &data))
data = -1;
if (log)
log->Printf("ProcessMonitor::%s() received exit? event, data = %lx, tid "
"= %" PRIu64,
__FUNCTION__, data, tid);
message = ProcessMessage::Limbo(tid, (data >> 8));
break;
}
case 0:
case TRAP_TRACE:
#ifdef TRAP_CAP
// Map TRAP_CAP to a trace trap in the absense of a more specific handler.
case TRAP_CAP:
#endif
if (log)
log->Printf("ProcessMonitor::%s() received trace event, tid = %" PRIu64
" : si_code = %d",
__FUNCTION__, tid, info->si_code);
message = ProcessMessage::Trace(tid);
break;
case SI_KERNEL:
case TRAP_BRKPT:
if (monitor->m_process->IsSoftwareStepBreakpoint(tid)) {
if (log)
log->Printf("ProcessMonitor::%s() received sw single step breakpoint "
"event, tid = %" PRIu64,
__FUNCTION__, tid);
message = ProcessMessage::Trace(tid);
} else {
if (log)
log->Printf(
"ProcessMonitor::%s() received breakpoint event, tid = %" PRIu64,
__FUNCTION__, tid);
message = ProcessMessage::Break(tid);
}
break;
}
return message;
}
ProcessMessage ProcessMonitor::MonitorSignal(ProcessMonitor *monitor,
const siginfo_t *info,
lldb::tid_t tid) {
ProcessMessage message;
int signo = info->si_signo;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
// POSIX says that process behaviour is undefined after it ignores a SIGFPE,
// SIGILL, SIGSEGV, or SIGBUS *unless* that signal was generated by a
// kill(2) or raise(3). Similarly for tgkill(2) on FreeBSD.
//
// IOW, user generated signals never generate what we consider to be a
// "crash".
//
// Similarly, ACK signals generated by this monitor.
if (info->si_code == SI_USER) {
if (log)
log->Printf(
"ProcessMonitor::%s() received signal %s with code %s, pid = %d",
__FUNCTION__,
monitor->m_process->GetUnixSignals()->GetSignalAsCString(signo),
"SI_USER", info->si_pid);
if (info->si_pid == getpid())
return ProcessMessage::SignalDelivered(tid, signo);
else
return ProcessMessage::Signal(tid, signo);
}
if (log)
log->Printf(
"ProcessMonitor::%s() received signal %s", __FUNCTION__,
monitor->m_process->GetUnixSignals()->GetSignalAsCString(signo));
switch (signo) {
case SIGSEGV:
case SIGILL:
case SIGFPE:
case SIGBUS:
lldb::addr_t fault_addr = reinterpret_cast<lldb::addr_t>(info->si_addr);
const auto reason = GetCrashReason(*info);
return ProcessMessage::Crash(tid, reason, signo, fault_addr);
}
// Everything else is "normal" and does not require any special action on
// our part.
return ProcessMessage::Signal(tid, signo);
}
void ProcessMonitor::ServeOperation(OperationArgs *args) {
ProcessMonitor *monitor = args->m_monitor;
// We are finised with the arguments and are ready to go. Sync with the
// parent thread and start serving operations on the inferior.
sem_post(&args->m_semaphore);
for (;;) {
// wait for next pending operation
sem_wait(&monitor->m_operation_pending);
monitor->m_operation->Execute(monitor);
// notify calling thread that operation is complete
sem_post(&monitor->m_operation_done);
}
}
void ProcessMonitor::DoOperation(Operation *op) {
std::lock_guard<std::mutex> guard(m_operation_mutex);
m_operation = op;
// notify operation thread that an operation is ready to be processed
sem_post(&m_operation_pending);
// wait for operation to complete
sem_wait(&m_operation_done);
}
size_t ProcessMonitor::ReadMemory(lldb::addr_t vm_addr, void *buf, size_t size,
Status &error) {
size_t result;
ReadOperation op(vm_addr, buf, size, error, result);
DoOperation(&op);
return result;
}
size_t ProcessMonitor::WriteMemory(lldb::addr_t vm_addr, const void *buf,
size_t size, lldb_private::Status &error) {
size_t result;
WriteOperation op(vm_addr, buf, size, error, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::ReadRegisterValue(lldb::tid_t tid, unsigned offset,
const char *reg_name, unsigned size,
RegisterValue &value) {
bool result;
ReadRegOperation op(tid, offset, size, value, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::WriteRegisterValue(lldb::tid_t tid, unsigned offset,
const char *reg_name,
const RegisterValue &value) {
bool result;
WriteRegOperation op(tid, offset, value, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::ReadDebugRegisterValue(
lldb::tid_t tid, unsigned offset, const char *reg_name, unsigned size,
lldb_private::RegisterValue &value) {
bool result;
ReadDebugRegOperation op(tid, offset, size, value, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::WriteDebugRegisterValue(
lldb::tid_t tid, unsigned offset, const char *reg_name,
const lldb_private::RegisterValue &value) {
bool result;
WriteDebugRegOperation op(tid, offset, value, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::ReadGPR(lldb::tid_t tid, void *buf, size_t buf_size) {
bool result;
ReadGPROperation op(tid, buf, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::ReadFPR(lldb::tid_t tid, void *buf, size_t buf_size) {
bool result;
ReadFPROperation op(tid, buf, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::ReadRegisterSet(lldb::tid_t tid, void *buf,
size_t buf_size, unsigned int regset) {
return false;
}
bool ProcessMonitor::WriteGPR(lldb::tid_t tid, void *buf, size_t buf_size) {
bool result;
WriteGPROperation op(tid, buf, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::WriteFPR(lldb::tid_t tid, void *buf, size_t buf_size) {
bool result;
WriteFPROperation op(tid, buf, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::WriteRegisterSet(lldb::tid_t tid, void *buf,
size_t buf_size, unsigned int regset) {
return false;
}
bool ProcessMonitor::ReadThreadPointer(lldb::tid_t tid, lldb::addr_t &value) {
return false;
}
bool ProcessMonitor::Resume(lldb::tid_t unused, uint32_t signo) {
bool result;
Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
if (log) {
const char *signame =
m_process->GetUnixSignals()->GetSignalAsCString(signo);
if (signame == nullptr)
signame = "<none>";
log->Printf("ProcessMonitor::%s() resuming pid %" PRIu64 " with signal %s",
__FUNCTION__, GetPID(), signame);
}
ResumeOperation op(signo, result);
DoOperation(&op);
if (log)
log->Printf("ProcessMonitor::%s() resuming result = %s", __FUNCTION__,
result ? "true" : "false");
return result;
}
bool ProcessMonitor::SingleStep(lldb::tid_t unused, uint32_t signo) {
bool result;
SingleStepOperation op(signo, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::Kill() {
bool result;
KillOperation op(result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::GetLwpInfo(lldb::tid_t tid, void *lwpinfo,
int &ptrace_err) {
bool result;
LwpInfoOperation op(tid, lwpinfo, result, ptrace_err);
DoOperation(&op);
return result;
}
bool ProcessMonitor::ThreadSuspend(lldb::tid_t tid, bool suspend) {
bool result;
ThreadSuspendOperation op(tid, suspend, result);
DoOperation(&op);
return result;
}
bool ProcessMonitor::GetEventMessage(lldb::tid_t tid, unsigned long *message) {
bool result;
EventMessageOperation op(tid, message, result);
DoOperation(&op);
return result;
}
lldb_private::Status ProcessMonitor::Detach(lldb::tid_t tid) {
lldb_private::Status error;
if (tid != LLDB_INVALID_THREAD_ID) {
DetachOperation op(error);
DoOperation(&op);
}
return error;
}
bool ProcessMonitor::DupDescriptor(const FileSpec &file_spec, int fd,
int flags) {
int target_fd = open(file_spec.GetCString(), flags, 0666);
if (target_fd == -1)
return false;
if (dup2(target_fd, fd) == -1)
return false;
return (close(target_fd) == -1) ? false : true;
}
void ProcessMonitor::StopMonitoringChildProcess() {
if (m_monitor_thread.IsJoinable()) {
m_monitor_thread.Cancel();
m_monitor_thread.Join(nullptr);
m_monitor_thread.Reset();
}
}
void ProcessMonitor::StopMonitor() {
StopMonitoringChildProcess();
StopOpThread();
sem_destroy(&m_operation_pending);
sem_destroy(&m_operation_done);
if (m_terminal_fd >= 0) {
close(m_terminal_fd);
m_terminal_fd = -1;
}
}
// FIXME: On Linux, when a new thread is created, we receive to notifications,
// (1) a SIGTRAP|PTRACE_EVENT_CLONE from the main process thread with the
// child thread id as additional information, and (2) a SIGSTOP|SI_USER from
// the new child thread indicating that it has is stopped because we attached.
// We have no guarantee of the order in which these arrive, but we need both
// before we are ready to proceed. We currently keep a list of threads which
// have sent the initial SIGSTOP|SI_USER event. Then when we receive the
// SIGTRAP|PTRACE_EVENT_CLONE notification, if the initial stop has not occurred
// we call ProcessMonitor::WaitForInitialTIDStop() to wait for it.
//
// Right now, the above logic is in ProcessPOSIX, so we need a definition of
// this function in the FreeBSD ProcessMonitor implementation even if it isn't
// logically needed.
//
// We really should figure out what actually happens on FreeBSD and move the
// Linux-specific logic out of ProcessPOSIX as needed.
bool ProcessMonitor::WaitForInitialTIDStop(lldb::tid_t tid) { return true; }
void ProcessMonitor::StopOpThread() {
if (!m_operation_thread.IsJoinable())
return;
m_operation_thread.Cancel();
m_operation_thread.Join(nullptr);
m_operation_thread.Reset();
}
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