1 //===-- Terminal.cpp --------------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "lldb/Host/Terminal.h"
11 
12 #include "lldb/Host/PosixApi.h"
13 #include "llvm/ADT/STLExtras.h"
14 
15 #include <fcntl.h>
16 #include <signal.h>
17 
18 #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
19 #include <termios.h>
20 #endif
21 
22 using namespace lldb_private;
23 
24 bool Terminal::IsATerminal() const { return m_fd >= 0 && ::isatty(m_fd); }
25 
26 bool Terminal::SetEcho(bool enabled) {
27   if (FileDescriptorIsValid()) {
28 #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
29     if (IsATerminal()) {
30       struct termios fd_termios;
31       if (::tcgetattr(m_fd, &fd_termios) == 0) {
32         bool set_corectly = false;
33         if (enabled) {
34           if (fd_termios.c_lflag & ECHO)
35             set_corectly = true;
36           else
37             fd_termios.c_lflag |= ECHO;
38         } else {
39           if (fd_termios.c_lflag & ECHO)
40             fd_termios.c_lflag &= ~ECHO;
41           else
42             set_corectly = true;
43         }
44 
45         if (set_corectly)
46           return true;
47         return ::tcsetattr(m_fd, TCSANOW, &fd_termios) == 0;
48       }
49     }
50 #endif // #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
51   }
52   return false;
53 }
54 
55 bool Terminal::SetCanonical(bool enabled) {
56   if (FileDescriptorIsValid()) {
57 #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
58     if (IsATerminal()) {
59       struct termios fd_termios;
60       if (::tcgetattr(m_fd, &fd_termios) == 0) {
61         bool set_corectly = false;
62         if (enabled) {
63           if (fd_termios.c_lflag & ICANON)
64             set_corectly = true;
65           else
66             fd_termios.c_lflag |= ICANON;
67         } else {
68           if (fd_termios.c_lflag & ICANON)
69             fd_termios.c_lflag &= ~ICANON;
70           else
71             set_corectly = true;
72         }
73 
74         if (set_corectly)
75           return true;
76         return ::tcsetattr(m_fd, TCSANOW, &fd_termios) == 0;
77       }
78     }
79 #endif // #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
80   }
81   return false;
82 }
83 
84 //----------------------------------------------------------------------
85 // Default constructor
86 //----------------------------------------------------------------------
87 TerminalState::TerminalState()
88     : m_tty(), m_tflags(-1),
89 #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
90       m_termios_ap(),
91 #endif
92       m_process_group(-1) {
93 }
94 
95 //----------------------------------------------------------------------
96 // Destructor
97 //----------------------------------------------------------------------
98 TerminalState::~TerminalState() {}
99 
100 void TerminalState::Clear() {
101   m_tty.Clear();
102   m_tflags = -1;
103 #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
104   m_termios_ap.reset();
105 #endif
106   m_process_group = -1;
107 }
108 
109 //----------------------------------------------------------------------
110 // Save the current state of the TTY for the file descriptor "fd"
111 // and if "save_process_group" is true, attempt to save the process
112 // group info for the TTY.
113 //----------------------------------------------------------------------
114 bool TerminalState::Save(int fd, bool save_process_group) {
115   m_tty.SetFileDescriptor(fd);
116   if (m_tty.IsATerminal()) {
117 #ifndef LLDB_DISABLE_POSIX
118     m_tflags = ::fcntl(fd, F_GETFL, 0);
119 #endif
120 #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
121     if (m_termios_ap.get() == NULL)
122       m_termios_ap.reset(new struct termios);
123     int err = ::tcgetattr(fd, m_termios_ap.get());
124     if (err != 0)
125       m_termios_ap.reset();
126 #endif // #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
127 #ifndef LLDB_DISABLE_POSIX
128     if (save_process_group)
129       m_process_group = ::tcgetpgrp(0);
130     else
131       m_process_group = -1;
132 #endif
133   } else {
134     m_tty.Clear();
135     m_tflags = -1;
136 #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
137     m_termios_ap.reset();
138 #endif
139     m_process_group = -1;
140   }
141   return IsValid();
142 }
143 
144 //----------------------------------------------------------------------
145 // Restore the state of the TTY using the cached values from a
146 // previous call to Save().
147 //----------------------------------------------------------------------
148 bool TerminalState::Restore() const {
149 #ifndef LLDB_DISABLE_POSIX
150   if (IsValid()) {
151     const int fd = m_tty.GetFileDescriptor();
152     if (TFlagsIsValid())
153       fcntl(fd, F_SETFL, m_tflags);
154 
155 #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
156     if (TTYStateIsValid())
157       tcsetattr(fd, TCSANOW, m_termios_ap.get());
158 #endif // #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
159 
160     if (ProcessGroupIsValid()) {
161       // Save the original signal handler.
162       void (*saved_sigttou_callback)(int) = NULL;
163       saved_sigttou_callback = (void (*)(int))signal(SIGTTOU, SIG_IGN);
164       // Set the process group
165       tcsetpgrp(fd, m_process_group);
166       // Restore the original signal handler.
167       signal(SIGTTOU, saved_sigttou_callback);
168     }
169     return true;
170   }
171 #endif
172   return false;
173 }
174 
175 //----------------------------------------------------------------------
176 // Returns true if this object has valid saved TTY state settings
177 // that can be used to restore a previous state.
178 //----------------------------------------------------------------------
179 bool TerminalState::IsValid() const {
180   return m_tty.FileDescriptorIsValid() &&
181          (TFlagsIsValid() || TTYStateIsValid());
182 }
183 
184 //----------------------------------------------------------------------
185 // Returns true if m_tflags is valid
186 //----------------------------------------------------------------------
187 bool TerminalState::TFlagsIsValid() const { return m_tflags != -1; }
188 
189 //----------------------------------------------------------------------
190 // Returns true if m_ttystate is valid
191 //----------------------------------------------------------------------
192 bool TerminalState::TTYStateIsValid() const {
193 #ifdef LLDB_CONFIG_TERMIOS_SUPPORTED
194   return m_termios_ap.get() != 0;
195 #else
196   return false;
197 #endif
198 }
199 
200 //----------------------------------------------------------------------
201 // Returns true if m_process_group is valid
202 //----------------------------------------------------------------------
203 bool TerminalState::ProcessGroupIsValid() const {
204   return static_cast<int32_t>(m_process_group) != -1;
205 }
206 
207 //------------------------------------------------------------------
208 // Constructor
209 //------------------------------------------------------------------
210 TerminalStateSwitcher::TerminalStateSwitcher() : m_currentState(UINT32_MAX) {}
211 
212 //------------------------------------------------------------------
213 // Destructor
214 //------------------------------------------------------------------
215 TerminalStateSwitcher::~TerminalStateSwitcher() {}
216 
217 //------------------------------------------------------------------
218 // Returns the number of states that this switcher contains
219 //------------------------------------------------------------------
220 uint32_t TerminalStateSwitcher::GetNumberOfStates() const {
221   return llvm::array_lengthof(m_ttystates);
222 }
223 
224 //------------------------------------------------------------------
225 // Restore the state at index "idx".
226 //
227 // Returns true if the restore was successful, false otherwise.
228 //------------------------------------------------------------------
229 bool TerminalStateSwitcher::Restore(uint32_t idx) const {
230   const uint32_t num_states = GetNumberOfStates();
231   if (idx >= num_states)
232     return false;
233 
234   // See if we already are in this state?
235   if (m_currentState < num_states && (idx == m_currentState) &&
236       m_ttystates[idx].IsValid())
237     return true;
238 
239   // Set the state to match the index passed in and only update the
240   // current state if there are no errors.
241   if (m_ttystates[idx].Restore()) {
242     m_currentState = idx;
243     return true;
244   }
245 
246   // We failed to set the state. The tty state was invalid or not
247   // initialized.
248   return false;
249 }
250 
251 //------------------------------------------------------------------
252 // Save the state at index "idx" for file descriptor "fd" and
253 // save the process group if requested.
254 //
255 // Returns true if the restore was successful, false otherwise.
256 //------------------------------------------------------------------
257 bool TerminalStateSwitcher::Save(uint32_t idx, int fd,
258                                  bool save_process_group) {
259   const uint32_t num_states = GetNumberOfStates();
260   if (idx < num_states)
261     return m_ttystates[idx].Save(fd, save_process_group);
262   return false;
263 }
264