1//===-- ProcessMonitor.h -------------------------------------- -*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef liblldb_ProcessMonitor_H_
10#define liblldb_ProcessMonitor_H_
11
12#include <semaphore.h>
13#include <signal.h>
14
15#include <mutex>
16
17#include "lldb/Host/HostThread.h"
18#include "lldb/Utility/FileSpec.h"
19#include "lldb/lldb-types.h"
20
21namespace lldb_private {
22class Status;
23class Module;
24class Scalar;
25} // End lldb_private namespace.
26
27class ProcessFreeBSD;
28class Operation;
29
30/// \class ProcessMonitor
31/// Manages communication with the inferior (debugee) process.
32///
33/// Upon construction, this class prepares and launches an inferior process
34/// for debugging.
35///
36/// Changes in the inferior process state are propagated to the associated
37/// ProcessFreeBSD instance by calling ProcessFreeBSD::SendMessage with the
38/// appropriate ProcessMessage events.
39///
40/// A purposely minimal set of operations are provided to interrogate and change
41/// the inferior process state.
42class ProcessMonitor {
43public:
44  /// Launches an inferior process ready for debugging.  Forms the
45  /// implementation of Process::DoLaunch.
46  ProcessMonitor(ProcessFreeBSD *process, lldb_private::Module *module,
47                 char const *argv[], lldb_private::Environment env,
48                 const lldb_private::FileSpec &stdin_file_spec,
49                 const lldb_private::FileSpec &stdout_file_spec,
50                 const lldb_private::FileSpec &stderr_file_spec,
51                 const lldb_private::FileSpec &working_dir,
52                 const lldb_private::ProcessLaunchInfo &launch_info,
53                 lldb_private::Status &error);
54
55  ProcessMonitor(ProcessFreeBSD *process, lldb::pid_t pid,
56                 lldb_private::Status &error);
57
58  ~ProcessMonitor();
59
60  /// Provides the process number of debugee.
61  lldb::pid_t GetPID() const { return m_pid; }
62
63  /// Returns the process associated with this ProcessMonitor.
64  ProcessFreeBSD &GetProcess() { return *m_process; }
65
66  /// Returns a file descriptor to the controlling terminal of the inferior
67  /// process.
68  ///
69  /// Reads from this file descriptor yield both the standard output and
70  /// standard error of this debugee.  Even if stderr and stdout were
71  /// redirected on launch it may still happen that data is available on this
72  /// descriptor (if the inferior process opens /dev/tty, for example). This
73  /// descriptor is closed after a call to StopMonitor().
74  ///
75  /// If this monitor was attached to an existing process this method returns
76  /// -1.
77  int GetTerminalFD() const { return m_terminal_fd; }
78
79  /// Reads \p size bytes from address @vm_adder in the inferior process
80  /// address space.
81  ///
82  /// This method is provided to implement Process::DoReadMemory.
83  size_t ReadMemory(lldb::addr_t vm_addr, void *buf, size_t size,
84                    lldb_private::Status &error);
85
86  /// Writes \p size bytes from address \p vm_adder in the inferior process
87  /// address space.
88  ///
89  /// This method is provided to implement Process::DoWriteMemory.
90  size_t WriteMemory(lldb::addr_t vm_addr, const void *buf, size_t size,
91                     lldb_private::Status &error);
92
93  /// Reads the contents from the register identified by the given
94  /// (architecture dependent) offset.
95  ///
96  /// This method is provided for use by RegisterContextFreeBSD derivatives.
97  bool ReadRegisterValue(lldb::tid_t tid, unsigned offset, const char *reg_name,
98                         unsigned size, lldb_private::RegisterValue &value);
99
100  /// Writes the given value to the register identified by the given
101  /// (architecture dependent) offset.
102  ///
103  /// This method is provided for use by RegisterContextFreeBSD derivatives.
104  bool WriteRegisterValue(lldb::tid_t tid, unsigned offset,
105                          const char *reg_name,
106                          const lldb_private::RegisterValue &value);
107
108  /// Reads the contents from the debug register identified by the given
109  /// (architecture dependent) offset.
110  ///
111  /// This method is provided for use by RegisterContextFreeBSD derivatives.
112  bool ReadDebugRegisterValue(lldb::tid_t tid, unsigned offset,
113                              const char *reg_name, unsigned size,
114                              lldb_private::RegisterValue &value);
115
116  /// Writes the given value to the debug register identified by the given
117  /// (architecture dependent) offset.
118  ///
119  /// This method is provided for use by RegisterContextFreeBSD derivatives.
120  bool WriteDebugRegisterValue(lldb::tid_t tid, unsigned offset,
121                               const char *reg_name,
122                               const lldb_private::RegisterValue &value);
123  /// Reads all general purpose registers into the specified buffer.
124  bool ReadGPR(lldb::tid_t tid, void *buf, size_t buf_size);
125
126  /// Reads all floating point registers into the specified buffer.
127  bool ReadFPR(lldb::tid_t tid, void *buf, size_t buf_size);
128
129  /// Reads the specified register set into the specified buffer.
130  ///
131  /// This method is provided for use by RegisterContextFreeBSD derivatives.
132  bool ReadRegisterSet(lldb::tid_t tid, void *buf, size_t buf_size,
133                       unsigned int regset);
134
135  /// Writes all general purpose registers into the specified buffer.
136  bool WriteGPR(lldb::tid_t tid, void *buf, size_t buf_size);
137
138  /// Writes all floating point registers into the specified buffer.
139  bool WriteFPR(lldb::tid_t tid, void *buf, size_t buf_size);
140
141  /// Writes the specified register set into the specified buffer.
142  ///
143  /// This method is provided for use by RegisterContextFreeBSD derivatives.
144  bool WriteRegisterSet(lldb::tid_t tid, void *buf, size_t buf_size,
145                        unsigned int regset);
146
147  /// Reads the value of the thread-specific pointer for a given thread ID.
148  bool ReadThreadPointer(lldb::tid_t tid, lldb::addr_t &value);
149
150  /// Returns current thread IDs in process
151  size_t GetCurrentThreadIDs(std::vector<lldb::tid_t> &thread_ids);
152
153  /// Writes a ptrace_lwpinfo structure corresponding to the given thread ID
154  /// to the memory region pointed to by \p lwpinfo.
155  bool GetLwpInfo(lldb::tid_t tid, void *lwpinfo, int &error_no);
156
157  /// Suspends or unsuspends a thread prior to process resume or step.
158  bool ThreadSuspend(lldb::tid_t tid, bool suspend);
159
160  /// Writes the raw event message code (vis-a-vis PTRACE_GETEVENTMSG)
161  /// corresponding to the given thread IDto the memory pointed to by @p
162  /// message.
163  bool GetEventMessage(lldb::tid_t tid, unsigned long *message);
164
165  /// Resumes the process.  If \p signo is anything but
166  /// LLDB_INVALID_SIGNAL_NUMBER, deliver that signal to the process.
167  bool Resume(lldb::tid_t unused, uint32_t signo);
168
169  /// Single steps the process.  If \p signo is anything but
170  /// LLDB_INVALID_SIGNAL_NUMBER, deliver that signal to the process.
171  bool SingleStep(lldb::tid_t unused, uint32_t signo);
172
173  /// Terminate the traced process.
174  bool Kill();
175
176  lldb_private::Status Detach(lldb::tid_t tid);
177
178  void StopMonitor();
179
180  // Waits for the initial stop message from a new thread.
181  bool WaitForInitialTIDStop(lldb::tid_t tid);
182
183private:
184  ProcessFreeBSD *m_process;
185
186  llvm::Optional<lldb_private::HostThread> m_operation_thread;
187  llvm::Optional<lldb_private::HostThread> m_monitor_thread;
188  lldb::pid_t m_pid;
189
190  int m_terminal_fd;
191
192  // current operation which must be executed on the privileged thread
193  Operation *m_operation;
194  std::mutex m_operation_mutex;
195
196  // semaphores notified when Operation is ready to be processed and when
197  // the operation is complete.
198  sem_t m_operation_pending;
199  sem_t m_operation_done;
200
201  struct OperationArgs {
202    OperationArgs(ProcessMonitor *monitor);
203
204    ~OperationArgs();
205
206    ProcessMonitor *m_monitor;   // The monitor performing the attach.
207    sem_t m_semaphore;           // Posted to once operation complete.
208    lldb_private::Status m_error; // Set if process operation failed.
209  };
210
211  /// \class LauchArgs
212  ///
213  /// Simple structure to pass data to the thread responsible for launching a
214  /// child process.
215  struct LaunchArgs : OperationArgs {
216    LaunchArgs(ProcessMonitor *monitor, lldb_private::Module *module,
217               char const **argv, lldb_private::Environment env,
218               const lldb_private::FileSpec &stdin_file_spec,
219               const lldb_private::FileSpec &stdout_file_spec,
220               const lldb_private::FileSpec &stderr_file_spec,
221               const lldb_private::FileSpec &working_dir);
222
223    ~LaunchArgs();
224
225    lldb_private::Module *m_module; // The executable image to launch.
226    char const **m_argv;            // Process arguments.
227    lldb_private::Environment m_env;                // Process environment.
228    const lldb_private::FileSpec m_stdin_file_spec; // Redirect stdin or empty.
229    const lldb_private::FileSpec
230        m_stdout_file_spec; // Redirect stdout or empty.
231    const lldb_private::FileSpec
232        m_stderr_file_spec;                     // Redirect stderr or empty.
233    const lldb_private::FileSpec m_working_dir; // Working directory or empty.
234  };
235
236  void StartLaunchOpThread(LaunchArgs *args, lldb_private::Status &error);
237
238  static void *LaunchOpThread(void *arg);
239
240  static bool Launch(LaunchArgs *args);
241
242  struct AttachArgs : OperationArgs {
243    AttachArgs(ProcessMonitor *monitor, lldb::pid_t pid);
244
245    ~AttachArgs();
246
247    lldb::pid_t m_pid; // pid of the process to be attached.
248  };
249
250  void StartAttachOpThread(AttachArgs *args, lldb_private::Status &error);
251
252  static void *AttachOpThread(void *args);
253
254  static void Attach(AttachArgs *args);
255
256  static void ServeOperation(OperationArgs *args);
257
258  static bool DupDescriptor(const lldb_private::FileSpec &file_spec, int fd,
259                            int flags);
260
261  static bool MonitorCallback(ProcessMonitor *monitor, lldb::pid_t pid,
262                              bool exited, int signal, int status);
263
264  static ProcessMessage MonitorSIGTRAP(ProcessMonitor *monitor,
265                                       const siginfo_t *info, lldb::pid_t pid);
266
267  static ProcessMessage MonitorSignal(ProcessMonitor *monitor,
268                                      const siginfo_t *info, lldb::pid_t pid);
269
270  void DoOperation(Operation *op);
271
272  /// Stops the child monitor thread.
273  void StopMonitoringChildProcess();
274
275  /// Stops the operation thread used to attach/launch a process.
276  void StopOpThread();
277};
278
279#endif // #ifndef liblldb_ProcessMonitor_H_
280