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 18TTYState::TTYState() 19 : m_fd(-1), m_tflags(-1), m_ttystateErr(-1), m_processGroup(-1) {} 20 21TTYState::~TTYState() = default; 22 23bool 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 41bool 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 63TTYStateSwitcher::TTYStateSwitcher() : m_currentState(~0) {} 64 65TTYStateSwitcher::~TTYStateSwitcher() = default; 66 67bool 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 73bool 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