Revert "constty(4): Make MP-safe."
Something is still busted and this is interfering with the releng amd64 testbed.
This commit is contained in:
riastradh
parent
73f2698769
commit
35c7b9ba47
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@ -1,4 +1,4 @@
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/* $NetBSD: cons.c,v 1.89 2022/10/07 18:55:50 riastradh Exp $ */
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/* $NetBSD: cons.c,v 1.90 2022/10/07 18:59:37 riastradh Exp $ */
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/*
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* Copyright (c) 1988 University of Utah.
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@ -39,7 +39,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: cons.c,v 1.89 2022/10/07 18:55:50 riastradh Exp $");
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__KERNEL_RCSID(0, "$NetBSD: cons.c,v 1.90 2022/10/07 18:59:37 riastradh Exp $");
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#include <sys/param.h>
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#include <sys/proc.h>
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@ -54,8 +54,6 @@ __KERNEL_RCSID(0, "$NetBSD: cons.c,v 1.89 2022/10/07 18:55:50 riastradh Exp $");
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#include <sys/kauth.h>
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#include <sys/mutex.h>
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#include <sys/module.h>
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#include <sys/atomic.h>
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#include <sys/pserialize.h>
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#include <dev/cons.h>
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@ -69,8 +67,7 @@ dev_type_ioctl(cnioctl);
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dev_type_poll(cnpoll);
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dev_type_kqfilter(cnkqfilter);
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static bool cn_redirect(dev_t *, int, int *, struct tty **);
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static void cn_release(struct tty *);
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static bool cn_redirect(dev_t *, int, int *);
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const struct cdevsw cons_cdevsw = {
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.d_open = cnopen,
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@ -89,7 +86,7 @@ const struct cdevsw cons_cdevsw = {
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static struct kmutex cn_lock;
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struct tty *volatile constty; /* virtual console output device */
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struct tty *constty = NULL; /* virtual console output device */
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struct consdev *cn_tab; /* physical console device info */
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struct vnode *cn_devvp[2]; /* vnode for underlying device. */
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@ -202,7 +199,6 @@ out: mutex_exit(&cn_lock);
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int
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cnread(dev_t dev, struct uio *uio, int flag)
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{
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struct tty *ctp = NULL;
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int error;
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/*
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@ -212,31 +208,25 @@ cnread(dev_t dev, struct uio *uio, int flag)
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* input (except a shell in single-user mode, but then,
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* one wouldn't TIOCCONS then).
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*/
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if (!cn_redirect(&dev, 1, &error, &ctp))
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if (!cn_redirect(&dev, 1, &error))
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return error;
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error = cdev_read(dev, uio, flag);
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cn_release(ctp);
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return error;
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return cdev_read(dev, uio, flag);
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}
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int
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cnwrite(dev_t dev, struct uio *uio, int flag)
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{
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struct tty *ctp = NULL;
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int error;
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/* Redirect output, if that's appropriate. */
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if (!cn_redirect(&dev, 0, &error, &ctp))
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if (!cn_redirect(&dev, 0, &error))
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return error;
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error = cdev_write(dev, uio, flag);
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cn_release(ctp);
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return error;
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return cdev_write(dev, uio, flag);
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}
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int
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cnioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
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{
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struct tty *ctp = NULL;
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int error;
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error = 0;
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@ -245,41 +235,29 @@ cnioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
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* Superuser can always use this to wrest control of console
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* output from the "virtual" console.
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*/
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if (cmd == TIOCCONS) {
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struct tty *tp;
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mutex_enter(&constty_lock);
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tp = atomic_load_relaxed(&constty);
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if (tp == NULL) {
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mutex_exit(&constty_lock);
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goto passthrough; /* XXX ??? */
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}
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if (cmd == TIOCCONS && constty != NULL) {
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error = kauth_authorize_device_tty(l->l_cred,
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KAUTH_DEVICE_TTY_VIRTUAL, tp);
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KAUTH_DEVICE_TTY_VIRTUAL, constty);
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if (!error)
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atomic_store_relaxed(&constty, NULL);
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mutex_exit(&constty_lock);
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return error;
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constty = NULL;
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return (error);
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}
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passthrough:
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/*
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* Redirect the ioctl, if that's appropriate.
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* Note that strange things can happen, if a program does
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* ioctls on /dev/console, then the console is redirected
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* out from under it.
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*/
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if (!cn_redirect(&dev, 0, &error, &ctp))
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if (!cn_redirect(&dev, 0, &error))
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return error;
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error = cdev_ioctl(dev, cmd, data, flag, l);
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cn_release(ctp);
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return error;
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return cdev_ioctl(dev, cmd, data, flag, l);
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}
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/*ARGSUSED*/
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int
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cnpoll(dev_t dev, int events, struct lwp *l)
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{
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struct tty *ctp = NULL;
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int error;
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/*
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@ -287,18 +265,15 @@ cnpoll(dev_t dev, int events, struct lwp *l)
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* I don't want to think of the possible side effects
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* of console redirection here.
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*/
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if (!cn_redirect(&dev, 0, &error, &ctp))
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if (!cn_redirect(&dev, 0, &error))
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return POLLHUP;
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error = cdev_poll(dev, events, l);
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cn_release(ctp);
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return error;
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return cdev_poll(dev, events, l);
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}
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/*ARGSUSED*/
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int
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cnkqfilter(dev_t dev, struct knote *kn)
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{
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struct tty *ctp = NULL;
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int error;
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/*
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@ -306,11 +281,9 @@ cnkqfilter(dev_t dev, struct knote *kn)
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* I don't want to think of the possible side effects
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* of console redirection here.
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*/
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if (!cn_redirect(&dev, 0, &error, &ctp))
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if (!cn_redirect(&dev, 0, &error))
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return error;
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error = cdev_kqfilter(dev, kn);
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cn_release(ctp);
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return error;
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return cdev_kqfilter(dev, kn);
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}
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int
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@ -456,44 +429,28 @@ cnhalt(void)
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/*
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* Redirect output, if that's appropriate. If there's no real console,
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* return ENXIO.
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*
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* Call with tty_mutex held.
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*/
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static bool
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cn_redirect(dev_t *devp, int is_read, int *error, struct tty **ctpp)
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cn_redirect(dev_t *devp, int is_read, int *error)
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{
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dev_t dev = *devp;
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struct tty *ctp;
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int s;
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bool ok = false;
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*error = ENXIO;
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*ctpp = NULL;
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s = pserialize_read_enter();
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if ((ctp = atomic_load_consume(&constty)) != NULL && minor(dev) == 0 &&
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if (constty != NULL && minor(dev) == 0 &&
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(cn_tab == NULL || (cn_tab->cn_pri != CN_REMOTE))) {
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if (is_read) {
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*error = 0;
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goto out;
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return false;
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}
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tty_acquire(ctp);
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*ctpp = ctp;
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dev = ctp->t_dev;
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dev = constty->t_dev;
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} else if (cn_tab == NULL)
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goto out;
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return false;
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else
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dev = cn_tab->cn_dev;
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ok = true;
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*devp = dev;
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out: pserialize_read_exit(s);
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return ok;
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}
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static void
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cn_release(struct tty *ctp)
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{
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if (ctp == NULL)
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return;
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tty_release(ctp);
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return true;
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}
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MODULE(MODULE_CLASS_DRIVER, cons, NULL);
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@ -1,4 +1,4 @@
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/* $NetBSD: subr_prf.c,v 1.192 2022/10/06 19:58:41 riastradh Exp $ */
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/* $NetBSD: subr_prf.c,v 1.193 2022/10/07 18:59:37 riastradh Exp $ */
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/*-
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* Copyright (c) 1986, 1988, 1991, 1993
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@ -37,7 +37,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: subr_prf.c,v 1.192 2022/10/06 19:58:41 riastradh Exp $");
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__KERNEL_RCSID(0, "$NetBSD: subr_prf.c,v 1.193 2022/10/07 18:59:37 riastradh Exp $");
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#ifdef _KERNEL_OPT
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#include "opt_ddb.h"
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@ -103,6 +103,7 @@ static void kprintf_internal(const char *, int, void *, char *, ...);
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* globals
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*/
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extern struct tty *constty; /* pointer to console "window" tty */
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extern int log_open; /* subr_log: is /dev/klog open? */
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const char *panicstr; /* arg to first call to panic (used as a flag
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to indicate that panic has already been called). */
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@ -400,35 +401,22 @@ addlog(const char *fmt, ...)
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static void
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putone(int c, int flags, struct tty *tp)
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{
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struct tty *ctp;
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int s;
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/*
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* Ensure whatever constty points to can't go away while we're
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* trying to use it.
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*/
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s = pserialize_read_enter();
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if (panicstr)
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atomic_store_relaxed(&constty, NULL);
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constty = NULL;
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if ((flags & TOCONS) &&
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(ctp = atomic_load_consume(&constty)) != NULL &&
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tp == NULL) {
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tp = ctp;
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if ((flags & TOCONS) && tp == NULL && constty) {
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tp = constty;
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flags |= TOTTY;
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}
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if ((flags & TOTTY) && tp &&
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tputchar(c, flags, tp) < 0 &&
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(flags & TOCONS))
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atomic_cas_ptr(&constty, tp, NULL);
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(flags & TOCONS) && tp == constty)
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constty = NULL;
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if ((flags & TOLOG) &&
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c != '\0' && c != '\r' && c != 0177)
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logputchar(c);
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if ((flags & TOCONS) && ctp == NULL && c != '\0')
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if ((flags & TOCONS) && constty == NULL && c != '\0')
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(*v_putc)(c);
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pserialize_read_exit(s);
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}
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static void
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114
sys/kern/tty.c
114
sys/kern/tty.c
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@ -1,4 +1,4 @@
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/* $NetBSD: tty.c,v 1.304 2022/10/06 19:58:41 riastradh Exp $ */
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/* $NetBSD: tty.c,v 1.305 2022/10/07 18:59:37 riastradh Exp $ */
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/*-
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* Copyright (c) 2008, 2020 The NetBSD Foundation, Inc.
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@ -63,7 +63,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: tty.c,v 1.304 2022/10/06 19:58:41 riastradh Exp $");
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__KERNEL_RCSID(0, "$NetBSD: tty.c,v 1.305 2022/10/07 18:59:37 riastradh Exp $");
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#ifdef _KERNEL_OPT
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#include "opt_compat_netbsd.h"
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@ -99,9 +99,6 @@ __KERNEL_RCSID(0, "$NetBSD: tty.c,v 1.304 2022/10/06 19:58:41 riastradh Exp $");
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#include <sys/module.h>
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#include <sys/bitops.h>
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#include <sys/compat_stub.h>
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#include <sys/atomic.h>
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#include <sys/condvar.h>
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#include <sys/pserialize.h>
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#ifdef COMPAT_60
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#include <compat/sys/ttycom.h>
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@ -212,9 +209,6 @@ static void *tty_sigsih;
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struct ttylist_head ttylist = TAILQ_HEAD_INITIALIZER(ttylist);
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int tty_count;
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kmutex_t tty_lock;
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kmutex_t constty_lock;
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static struct pserialize *constty_psz;
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static kcondvar_t ttyref_cv;
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struct ptm_pty *ptm = NULL;
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@ -448,29 +442,14 @@ ttycancel(struct tty *tp)
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int
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ttyclose(struct tty *tp)
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{
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extern struct tty *constty; /* Temporary virtual console. */
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struct session *sess;
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/*
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* Make sure this is not the constty. Without constty_lock it
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* is always allowed to transition from nonnull to null.
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*/
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(void)atomic_cas_ptr(&constty, tp, NULL);
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/*
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* We don't know if this has _ever_ been the constty: another
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* thread may have kicked it out as constty before we started
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* to close.
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*
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* So we wait for all users that might be acquiring references
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* to finish doing so -- after that, no more references can be
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* made, at which point we can safely flush the tty, wait for
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* the existing references to drain, and finally free or reuse
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* the tty.
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*/
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pserialize_perform(constty_psz);
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mutex_spin_enter(&tty_lock);
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if (constty == tp)
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constty = NULL;
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ttyflush(tp, FREAD | FWRITE);
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tp->t_gen++;
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@ -479,9 +458,6 @@ ttyclose(struct tty *tp)
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sess = tp->t_session;
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tp->t_session = NULL;
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while (tp->t_refcnt)
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cv_wait(&ttyref_cv, &tty_lock);
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mutex_spin_exit(&tty_lock);
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if (sess != NULL) {
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@ -497,44 +473,6 @@ ttyclose(struct tty *tp)
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ndflush(q, (q)->c_cc); \
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}
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/*
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* tty_acquire(tp), tty_release(tp)
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*
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* Acquire a reference to tp that prevents it from being closed
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* until released. Caller must guarantee tp has not yet been
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* closed, e.g. by obtaining tp from constty during a pserialize
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* read section. Caller must not hold tty_lock.
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*/
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void
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tty_acquire(struct tty *tp)
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{
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unsigned refcnt __diagused;
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refcnt = atomic_inc_uint_nv(&tp->t_refcnt);
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KASSERT(refcnt < UINT_MAX);
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}
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void
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tty_release(struct tty *tp)
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{
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unsigned old, new;
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KDASSERT(mutex_ownable(&tty_lock));
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do {
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old = atomic_load_relaxed(&tp->t_refcnt);
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if (old == 1) {
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mutex_spin_enter(&tty_lock);
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if (atomic_dec_uint_nv(&tp->t_refcnt) == 0)
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cv_broadcast(&ttyref_cv);
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mutex_spin_exit(&tty_lock);
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return;
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}
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KASSERT(old != 0);
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new = old - 1;
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} while (atomic_cas_uint(&tp->t_refcnt, old, new) != old);
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}
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/*
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* This macro is used in canonical mode input processing, where a read
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* request shall not return unless a 'line delimiter' ('\n') or 'break'
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@ -1003,6 +941,7 @@ ttyoutput(int c, struct tty *tp)
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int
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ttioctl(struct tty *tp, u_long cmd, void *data, int flag, struct lwp *l)
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{
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extern struct tty *constty; /* Temporary virtual console. */
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struct proc *p;
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struct linesw *lp;
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int s, error;
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@ -1105,47 +1044,32 @@ ttioctl(struct tty *tp, u_long cmd, void *data, int flag, struct lwp *l)
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mutex_spin_exit(&tty_lock);
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break;
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}
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case TIOCCONS: { /* become virtual console */
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struct tty *ctp;
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|
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mutex_enter(&constty_lock);
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error = 0;
|
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ctp = atomic_load_relaxed(&constty);
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case TIOCCONS: /* become virtual console */
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if (*(int *)data) {
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if (ctp != NULL && ctp != tp &&
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ISSET(ctp->t_state, TS_CARR_ON | TS_ISOPEN) ==
|
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(TS_CARR_ON | TS_ISOPEN)) {
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error = EBUSY;
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goto unlock_constty;
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}
|
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if (constty && constty != tp &&
|
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ISSET(constty->t_state, TS_CARR_ON | TS_ISOPEN) ==
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(TS_CARR_ON | TS_ISOPEN))
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return EBUSY;
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pb = pathbuf_create("/dev/console");
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if (pb == NULL) {
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error = ENOMEM;
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goto unlock_constty;
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return ENOMEM;
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}
|
||||
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, pb);
|
||||
if ((error = namei(&nd)) != 0) {
|
||||
pathbuf_destroy(pb);
|
||||
goto unlock_constty;
|
||||
return error;
|
||||
}
|
||||
error = VOP_ACCESS(nd.ni_vp, VREAD, l->l_cred);
|
||||
vput(nd.ni_vp);
|
||||
pathbuf_destroy(pb);
|
||||
if (error)
|
||||
goto unlock_constty;
|
||||
return error;
|
||||
|
||||
KASSERT(atomic_load_relaxed(&constty) == ctp ||
|
||||
atomic_load_relaxed(&constty) == NULL);
|
||||
atomic_store_release(&constty, tp);
|
||||
} else if (tp == ctp) {
|
||||
atomic_store_relaxed(&constty, NULL);
|
||||
}
|
||||
unlock_constty: mutex_exit(&constty_lock);
|
||||
if (error)
|
||||
return error;
|
||||
constty = tp;
|
||||
} else if (tp == constty)
|
||||
constty = NULL;
|
||||
break;
|
||||
}
|
||||
case TIOCDRAIN: /* wait till output drained */
|
||||
if ((error = ttywait(tp)) != 0)
|
||||
return (error);
|
||||
|
|
@ -3044,8 +2968,6 @@ tty_init(void)
|
|||
{
|
||||
|
||||
mutex_init(&tty_lock, MUTEX_DEFAULT, IPL_VM);
|
||||
mutex_init(&constty_lock, MUTEX_DEFAULT, IPL_NONE);
|
||||
constty_psz = pserialize_create();
|
||||
tty_sigsih = softint_establish(SOFTINT_CLOCK, ttysigintr, NULL);
|
||||
KASSERT(tty_sigsih != NULL);
|
||||
|
||||
|
|
|
|||
|
|
@ -1,4 +1,4 @@
|
|||
/* $NetBSD: tty.h,v 1.100 2022/10/06 19:58:41 riastradh Exp $ */
|
||||
/* $NetBSD: tty.h,v 1.101 2022/10/07 18:59:37 riastradh Exp $ */
|
||||
|
||||
/*-
|
||||
* Copyright (c) 2008 The NetBSD Foundation, Inc.
|
||||
|
|
@ -149,7 +149,6 @@ struct tty {
|
|||
int t_sigcount; /* # pending signals */
|
||||
TAILQ_ENTRY(tty) t_sigqueue; /* entry on pending signal list */
|
||||
void *t_softc; /* pointer to driver's softc. */
|
||||
volatile unsigned t_refcnt; /* reference count for constty */
|
||||
};
|
||||
|
||||
#ifdef TTY_ALLOW_PRIVATE
|
||||
|
|
@ -253,8 +252,6 @@ TAILQ_HEAD(ttylist_head, tty); /* the ttylist is a TAILQ */
|
|||
#ifdef _KERNEL
|
||||
|
||||
extern kmutex_t tty_lock;
|
||||
extern kmutex_t constty_lock;
|
||||
extern struct tty *volatile constty;
|
||||
|
||||
extern int tty_count; /* number of ttys in global ttylist */
|
||||
extern struct ttychars ttydefaults;
|
||||
|
|
@ -316,8 +313,6 @@ void tty_free(struct tty *);
|
|||
u_char *firstc(struct clist *, int *);
|
||||
bool ttypull(struct tty *);
|
||||
int tty_unit(dev_t);
|
||||
void tty_acquire(struct tty *);
|
||||
void tty_release(struct tty *);
|
||||
|
||||
int clalloc(struct clist *, int, int);
|
||||
void clfree(struct clist *);
|
||||
|
|
|
|||
Loading…
Reference in New Issue