// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 1991, 1992 Linus Torvalds */ #include <linux/types.h> #include <linux/errno.h> #include <linux/signal.h> #include <linux/sched/signal.h> #include <linux/sched/task.h> #include <linux/tty.h> #include <linux/fcntl.h> #include <linux/uaccess.h> #include "tty.h" static int is_ignored(int sig) { … } /** * __tty_check_change - check for POSIX terminal changes * @tty: tty to check * @sig: signal to send * * If we try to write to, or set the state of, a terminal and we're * not in the foreground, send a SIGTTOU. If the signal is blocked or * ignored, go ahead and perform the operation. (POSIX 7.2) * * Locking: ctrl.lock */ int __tty_check_change(struct tty_struct *tty, int sig) { … } int tty_check_change(struct tty_struct *tty) { … } EXPORT_SYMBOL(…); void proc_clear_tty(struct task_struct *p) { … } /** * __proc_set_tty - set the controlling terminal * @tty: tty structure * * Only callable by the session leader and only if it does not already have * a controlling terminal. * * Caller must hold: tty_lock() * a readlock on tasklist_lock * sighand lock */ static void __proc_set_tty(struct tty_struct *tty) { … } static void proc_set_tty(struct tty_struct *tty) { … } /* * Called by tty_open() to set the controlling tty if applicable. */ void tty_open_proc_set_tty(struct file *filp, struct tty_struct *tty) { … } struct tty_struct *get_current_tty(void) { … } EXPORT_SYMBOL_GPL(…); /* * Called from tty_release(). */ void session_clear_tty(struct pid *session) { … } /** * tty_signal_session_leader - sends SIGHUP to session leader * @tty: controlling tty * @exit_session: if non-zero, signal all foreground group processes * * Send SIGHUP and SIGCONT to the session leader and its process group. * Optionally, signal all processes in the foreground process group. * * Returns the number of processes in the session with this tty * as their controlling terminal. This value is used to drop * tty references for those processes. */ int tty_signal_session_leader(struct tty_struct *tty, int exit_session) { … } /** * disassociate_ctty - disconnect controlling tty * @on_exit: true if exiting so need to "hang up" the session * * This function is typically called only by the session leader, when * it wants to disassociate itself from its controlling tty. * * It performs the following functions: * (1) Sends a SIGHUP and SIGCONT to the foreground process group * (2) Clears the tty from being controlling the session * (3) Clears the controlling tty for all processes in the * session group. * * The argument on_exit is set to 1 if called when a process is * exiting; it is 0 if called by the ioctl TIOCNOTTY. * * Locking: * BTM is taken for hysterical raisons, and held when * called from no_tty(). * tty_mutex is taken to protect tty * ->siglock is taken to protect ->signal/->sighand * tasklist_lock is taken to walk process list for sessions * ->siglock is taken to protect ->signal/->sighand */ void disassociate_ctty(int on_exit) { … } /* * * no_tty - Ensure the current process does not have a controlling tty */ void no_tty(void) { … } /** * tiocsctty - set controlling tty * @tty: tty structure * @file: file structure used to check permissions * @arg: user argument * * This ioctl is used to manage job control. It permits a session * leader to set this tty as the controlling tty for the session. * * Locking: * Takes tty_lock() to serialize proc_set_tty() for this tty * Takes tasklist_lock internally to walk sessions * Takes ->siglock() when updating signal->tty */ static int tiocsctty(struct tty_struct *tty, struct file *file, int arg) { … } /** * tty_get_pgrp - return a ref counted pgrp pid * @tty: tty to read * * Returns a refcounted instance of the pid struct for the process * group controlling the tty. */ struct pid *tty_get_pgrp(struct tty_struct *tty) { … } EXPORT_SYMBOL_GPL(…); /* * This checks not only the pgrp, but falls back on the pid if no * satisfactory pgrp is found. I dunno - gdb doesn't work correctly * without this... * * The caller must hold rcu lock or the tasklist lock. */ static struct pid *session_of_pgrp(struct pid *pgrp) { … } /** * tiocgpgrp - get process group * @tty: tty passed by user * @real_tty: tty side of the tty passed by the user if a pty else the tty * @p: returned pid * * Obtain the process group of the tty. If there is no process group * return an error. * * Locking: none. Reference to current->signal->tty is safe. */ static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { … } /** * tiocspgrp - attempt to set process group * @tty: tty passed by user * @real_tty: tty side device matching tty passed by user * @p: pid pointer * * Set the process group of the tty to the session passed. Only * permitted where the tty session is our session. * * Locking: RCU, ctrl lock */ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { … } /** * tiocgsid - get session id * @tty: tty passed by user * @real_tty: tty side of the tty passed by the user if a pty else the tty * @p: pointer to returned session id * * Obtain the session id of the tty. If there is no session * return an error. */ static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { … } /* * Called from tty_ioctl(). If tty is a pty then real_tty is the slave side, * if not then tty == real_tty. */ long tty_jobctrl_ioctl(struct tty_struct *tty, struct tty_struct *real_tty, struct file *file, unsigned int cmd, unsigned long arg) { … }
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