1 //===-- TTYState.cpp --------------------------------------------*- 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 // Created by Greg Clayton on 3/26/07.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "TTYState.h"
14 #include <fcntl.h>
15 #include <sys/signal.h>
16 #include <unistd.h>
17
TTYState()18 TTYState::TTYState()
19 : m_fd(-1), m_tflags(-1), m_ttystateErr(-1), m_processGroup(-1) {}
20
~TTYState()21 TTYState::~TTYState() {}
22
GetTTYState(int fd,bool saveProcessGroup)23 bool TTYState::GetTTYState(int fd, bool saveProcessGroup) {
24 if (fd >= 0 && ::isatty(fd)) {
25 m_fd = fd;
26 m_tflags = fcntl(fd, F_GETFL, 0);
27 m_ttystateErr = tcgetattr(fd, &m_ttystate);
28 if (saveProcessGroup)
29 m_processGroup = tcgetpgrp(0);
30 else
31 m_processGroup = -1;
32 } else {
33 m_fd = -1;
34 m_tflags = -1;
35 m_ttystateErr = -1;
36 m_processGroup = -1;
37 }
38 return m_ttystateErr == 0;
39 }
40
SetTTYState() const41 bool TTYState::SetTTYState() const {
42 int result = 0;
43 if (IsValid()) {
44 if (TFlagsValid())
45 result = fcntl(m_fd, F_SETFL, m_tflags);
46
47 if (TTYStateValid())
48 result = tcsetattr(m_fd, TCSANOW, &m_ttystate);
49
50 if (ProcessGroupValid()) {
51 // Save the original signal handler.
52 void (*saved_sigttou_callback)(int) = NULL;
53 saved_sigttou_callback = (void (*)(int))signal(SIGTTOU, SIG_IGN);
54 // Set the process group
55 result = tcsetpgrp(m_fd, m_processGroup);
56 // Restore the original signal handler.
57 signal(SIGTTOU, saved_sigttou_callback);
58 }
59 return true;
60 }
61 return false;
62 }
63
TTYStateSwitcher()64 TTYStateSwitcher::TTYStateSwitcher() : m_currentState(~0) {}
65
~TTYStateSwitcher()66 TTYStateSwitcher::~TTYStateSwitcher() {}
67
GetState(uint32_t idx,int fd,bool saveProcessGroup)68 bool TTYStateSwitcher::GetState(uint32_t idx, int fd, bool saveProcessGroup) {
69 if (ValidStateIndex(idx))
70 return m_ttystates[idx].GetTTYState(fd, saveProcessGroup);
71 return false;
72 }
73
SetState(uint32_t idx) const74 bool TTYStateSwitcher::SetState(uint32_t idx) const {
75 if (!ValidStateIndex(idx))
76 return false;
77
78 // See if we already are in this state?
79 if (ValidStateIndex(m_currentState) && (idx == m_currentState) &&
80 m_ttystates[idx].IsValid())
81 return true;
82
83 // Set the state to match the index passed in and only update the
84 // current state if there are no errors.
85 if (m_ttystates[idx].SetTTYState()) {
86 m_currentState = idx;
87 return true;
88 }
89
90 // We failed to set the state. The tty state was invalid or not
91 // initialized.
92 return false;
93 }
94