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
21 TTYState::~TTYState() = default;
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 if (IsValid()) {
43 if (TFlagsValid())
44 fcntl(m_fd, F_SETFL, m_tflags);
45
46 if (TTYStateValid())
47 tcsetattr(m_fd, TCSANOW, &m_ttystate);
48
49 if (ProcessGroupValid()) {
50 // Save the original signal handler.
51 void (*saved_sigttou_callback)(int) = NULL;
52 saved_sigttou_callback = (void (*)(int))signal(SIGTTOU, SIG_IGN);
53 // Set the process group
54 tcsetpgrp(m_fd, m_processGroup);
55 // Restore the original signal handler.
56 signal(SIGTTOU, saved_sigttou_callback);
57 }
58 return true;
59 }
60 return false;
61 }
62
TTYStateSwitcher()63 TTYStateSwitcher::TTYStateSwitcher() : m_currentState(~0) {}
64
65 TTYStateSwitcher::~TTYStateSwitcher() = default;
66
GetState(uint32_t idx,int fd,bool saveProcessGroup)67 bool TTYStateSwitcher::GetState(uint32_t idx, int fd, bool saveProcessGroup) {
68 if (ValidStateIndex(idx))
69 return m_ttystates[idx].GetTTYState(fd, saveProcessGroup);
70 return false;
71 }
72
SetState(uint32_t idx) const73 bool TTYStateSwitcher::SetState(uint32_t idx) const {
74 if (!ValidStateIndex(idx))
75 return false;
76
77 // See if we already are in this state?
78 if (ValidStateIndex(m_currentState) && (idx == m_currentState) &&
79 m_ttystates[idx].IsValid())
80 return true;
81
82 // Set the state to match the index passed in and only update the
83 // current state if there are no errors.
84 if (m_ttystates[idx].SetTTYState()) {
85 m_currentState = idx;
86 return true;
87 }
88
89 // We failed to set the state. The tty state was invalid or not
90 // initialized.
91 return false;
92 }
93