Reimplement the /dev/console device node.
One of the pieces of code that I had left alone during the development of the MPSAFE TTY layer, was tty_cons.c. This file actually has two different functions: - It contains low-level console input/output routines (cnputc(), etc). - It creates /dev/console and wraps all its cdevsw calls to the appropriate TTY. This commit reimplements the second set of functions by moving it directly into the TTY layer. /dev/console is now a character device node that's basically a regular TTY, but does a lookup of `si_drv1' each time you open it. d_write has also been changed to call log_console(). d_close() is not present, because we must make sure we don't revoke the TTY after writing a log message to it. Even though I'm not convinced this is in line with the future directions of our console code, it is a good move for now. It removes recursive locking from the top half of the TTY layer. The previous implementation called into the TTY layer with Giant held. I'm renaming tty_cons.c to kern_cons.c now. The code hardly contains any TTY related bits, so we'd better give it a less misleading name. Tested by: Andrzej Tobola <ato iem pw edu pl>, Carlos A.M. dos Santos <unixmania gmail com>, Eygene Ryabinkin <rea-fbsd codelabs ru>
This commit is contained in:
Ed Schouten
parent
b75d197096
commit
c9dba40cc8
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=184521
@ -1596,6 +1596,7 @@ kern/kern_alq.c optional alq
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kern/kern_clock.c standard
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kern/kern_condvar.c standard
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kern/kern_conf.c standard
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kern/kern_cons.c standard
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kern/kern_cpu.c standard
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kern/kern_cpuset.c standard
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kern/kern_context.c standard
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@ -1708,7 +1709,6 @@ kern/sysv_sem.c optional sysvsem
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kern/sysv_shm.c optional sysvshm
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kern/tty.c standard
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kern/tty_compat.c optional compat_43tty
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kern/tty_cons.c standard
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kern/tty_info.c standard
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kern/tty_inq.c standard
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kern/tty_outq.c standard
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@ -68,30 +68,8 @@ __FBSDID("$FreeBSD$");
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static MALLOC_DEFINE(M_TTYCONS, "tty console", "tty console handling");
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static d_open_t cnopen;
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static d_close_t cnclose;
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static d_read_t cnread;
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static d_write_t cnwrite;
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static d_ioctl_t cnioctl;
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static d_poll_t cnpoll;
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static d_kqfilter_t cnkqfilter;
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static struct cdevsw cn_cdevsw = {
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.d_version = D_VERSION,
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.d_open = cnopen,
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.d_close = cnclose,
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.d_read = cnread,
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.d_write = cnwrite,
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.d_ioctl = cnioctl,
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.d_poll = cnpoll,
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.d_name = "console",
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.d_flags = D_TTY | D_NEEDGIANT,
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.d_kqfilter = cnkqfilter,
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};
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struct cn_device {
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STAILQ_ENTRY(cn_device) cnd_next;
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struct vnode *cnd_vp;
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struct consdev *cnd_cn;
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};
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@ -101,22 +79,12 @@ static struct cn_device cn_devtab[CNDEVTAB_SIZE];
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static STAILQ_HEAD(, cn_device) cn_devlist =
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STAILQ_HEAD_INITIALIZER(cn_devlist);
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#define CND_INVALID(cnd, td) \
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(cnd == NULL || cnd->cnd_vp == NULL || \
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(cnd->cnd_vp->v_type == VBAD && !cn_devopen(cnd, td, 1)))
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static dev_t cn_udev_t;
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SYSCTL_OPAQUE(_machdep, OID_AUTO, consdev, CTLFLAG_RD,
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&cn_udev_t, sizeof cn_udev_t, "T,struct cdev *", "");
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int cons_avail_mask = 0; /* Bit mask. Each registered low level console
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* which is currently unavailable for inpit
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* (i.e., if it is in graphics mode) will have
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* this bit cleared.
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*/
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static int cn_mute;
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static int openflag; /* how /dev/console was opened */
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static int cn_is_open;
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static char *consbuf; /* buffer used by `consmsgbuf' */
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static struct callout conscallout; /* callout for outputting to constty */
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struct msgbuf consmsgbuf; /* message buffer for console tty */
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@ -214,6 +182,8 @@ cnadd(struct consdev *cn)
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printf("WARNING: console at %p has no name\n", cn);
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}
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STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
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if (STAILQ_FIRST(&cn_devlist) == cnd)
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ttyconsdev_select(cnd->cnd_cn->cn_name);
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/* Add device to the active mask. */
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cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
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@ -230,10 +200,9 @@ cnremove(struct consdev *cn)
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STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
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if (cnd->cnd_cn != cn)
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continue;
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if (STAILQ_FIRST(&cn_devlist) == cnd)
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ttyconsdev_select(NULL);
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STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
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if (cnd->cnd_vp != NULL)
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vn_close(cnd->cnd_vp, openflag, NOCRED, NULL);
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cnd->cnd_vp = NULL;
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cnd->cnd_cn = NULL;
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/* Remove this device from available mask. */
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@ -267,6 +236,7 @@ cnselect(struct consdev *cn)
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return;
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STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
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STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
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ttyconsdev_select(cnd->cnd_cn->cn_name);
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return;
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}
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}
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@ -368,210 +338,12 @@ sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
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error = sysctl_handle_int(oidp, &cn_mute, 0, req);
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if (error != 0 || req->newptr == NULL)
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return (error);
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if (ocn_mute && !cn_mute && cn_is_open)
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error = cnopen(NULL, openflag, 0, curthread);
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else if (!ocn_mute && cn_mute && cn_is_open) {
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error = cnclose(NULL, openflag, 0, curthread);
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cn_is_open = 1; /* XXX hack */
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}
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return (error);
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}
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SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
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0, sizeof(cn_mute), sysctl_kern_consmute, "I", "");
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static int
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cn_devopen(struct cn_device *cnd, struct thread *td, int forceopen)
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{
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char path[CNDEVPATHMAX];
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struct nameidata nd;
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struct vnode *vp;
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struct cdev *dev;
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struct cdevsw *csw;
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int error;
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if ((vp = cnd->cnd_vp) != NULL) {
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if (!forceopen && vp->v_type != VBAD) {
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dev = vp->v_rdev;
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csw = dev_refthread(dev);
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if (csw == NULL)
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return (ENXIO);
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error = (*csw->d_open)(dev, openflag, 0, td);
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dev_relthread(dev);
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return (error);
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}
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cnd->cnd_vp = NULL;
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vn_close(vp, openflag, td->td_ucred, td);
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}
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snprintf(path, sizeof(path), "/dev/%s", cnd->cnd_cn->cn_name);
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, path, td);
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error = vn_open(&nd, &openflag, 0, NULL);
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if (error == 0) {
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NDFREE(&nd, NDF_ONLY_PNBUF);
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VOP_UNLOCK(nd.ni_vp, 0);
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if (nd.ni_vp->v_type == VCHR)
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cnd->cnd_vp = nd.ni_vp;
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else
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vn_close(nd.ni_vp, openflag, td->td_ucred, td);
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}
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return (cnd->cnd_vp != NULL);
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}
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static int
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cnopen(struct cdev *dev, int flag, int mode, struct thread *td)
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{
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struct cn_device *cnd;
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openflag = flag | FWRITE; /* XXX */
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cn_is_open = 1; /* console is logically open */
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if (cn_mute)
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return (0);
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STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
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cn_devopen(cnd, td, 0);
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return (0);
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}
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static int
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cnclose(struct cdev *dev, int flag, int mode, struct thread *td)
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{
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struct cn_device *cnd;
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struct vnode *vp;
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STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
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if ((vp = cnd->cnd_vp) == NULL)
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continue;
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cnd->cnd_vp = NULL;
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vn_close(vp, openflag, td->td_ucred, td);
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}
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cn_is_open = 0;
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return (0);
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}
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static int
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cnread(struct cdev *dev, struct uio *uio, int flag)
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{
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struct cn_device *cnd;
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struct cdevsw *csw;
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int error;
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cnd = STAILQ_FIRST(&cn_devlist);
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if (cn_mute || CND_INVALID(cnd, curthread))
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return (0);
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dev = cnd->cnd_vp->v_rdev;
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csw = dev_refthread(dev);
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if (csw == NULL)
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return (ENXIO);
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error = (csw->d_read)(dev, uio, flag);
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dev_relthread(dev);
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return (error);
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}
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static int
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cnwrite(struct cdev *dev, struct uio *uio, int flag)
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{
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struct cn_device *cnd;
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struct cdevsw *csw;
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int error;
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cnd = STAILQ_FIRST(&cn_devlist);
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if (cn_mute || CND_INVALID(cnd, curthread))
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goto done;
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if (constty)
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dev = constty->t_dev;
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else
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dev = cnd->cnd_vp->v_rdev;
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if (dev != NULL) {
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log_console(uio);
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csw = dev_refthread(dev);
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if (csw == NULL)
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return (ENXIO);
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error = (csw->d_write)(dev, uio, flag);
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dev_relthread(dev);
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return (error);
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}
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done:
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uio->uio_resid = 0; /* dump the data */
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return (0);
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}
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static int
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cnioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *td)
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{
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struct cn_device *cnd;
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struct cdevsw *csw;
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int error;
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cnd = STAILQ_FIRST(&cn_devlist);
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if (cn_mute || CND_INVALID(cnd, td))
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return (0);
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/*
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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 && constty) {
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error = priv_check(td, PRIV_TTY_CONSOLE);
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if (error)
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return (error);
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constty = NULL;
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return (0);
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}
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dev = cnd->cnd_vp->v_rdev;
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if (dev == NULL)
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return (0); /* XXX : ENOTTY ? */
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csw = dev_refthread(dev);
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if (csw == NULL)
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return (ENXIO);
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error = (csw->d_ioctl)(dev, cmd, data, flag, td);
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dev_relthread(dev);
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return (error);
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}
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/*
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* XXX
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* poll/kqfilter do not appear to be correct
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*/
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static int
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cnpoll(struct cdev *dev, int events, struct thread *td)
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{
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struct cn_device *cnd;
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struct cdevsw *csw;
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int error;
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cnd = STAILQ_FIRST(&cn_devlist);
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if (cn_mute || CND_INVALID(cnd, td))
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return (0);
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dev = cnd->cnd_vp->v_rdev;
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if (dev == NULL)
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return (0);
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csw = dev_refthread(dev);
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if (csw == NULL)
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return (ENXIO);
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error = (csw->d_poll)(dev, events, td);
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dev_relthread(dev);
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return (error);
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}
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static int
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cnkqfilter(struct cdev *dev, struct knote *kn)
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{
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struct cn_device *cnd;
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struct cdevsw *csw;
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int error;
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cnd = STAILQ_FIRST(&cn_devlist);
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if (cn_mute || CND_INVALID(cnd, curthread))
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return (EINVAL);
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dev = cnd->cnd_vp->v_rdev;
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if (dev == NULL)
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return (ENXIO);
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csw = dev_refthread(dev);
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if (csw == NULL)
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return (ENXIO);
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error = (csw->d_kqfilter)(dev, kn);
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dev_relthread(dev);
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return (error);
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}
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/*
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* Low level console routines.
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*/
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@ -737,8 +509,6 @@ static void
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cn_drvinit(void *unused)
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{
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make_dev(&cn_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "console");
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mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
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use_cnputs_mtx = 1;
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}
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@ -73,6 +73,10 @@ static struct sx tty_list_sx;
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SX_SYSINIT(tty_list, &tty_list_sx, "tty list");
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static unsigned int tty_list_count = 0;
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/* Character device of /dev/console. */
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static struct cdev *dev_console;
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static const char *dev_console_filename;
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/*
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* Flags that are supported and stored by this implementation.
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*/
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@ -86,7 +90,7 @@ static unsigned int tty_list_count = 0;
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HUPCL|CLOCAL|CCTS_OFLOW|CRTS_IFLOW|CDTR_IFLOW|\
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CDSR_OFLOW|CCAR_OFLOW)
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#define TTY_CALLOUT(tp,d) ((tp)->t_dev != (d))
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#define TTY_CALLOUT(tp,d) ((d) != (tp)->t_dev && (d) != dev_console)
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/*
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* Set TTY buffer sizes.
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@ -1189,11 +1193,7 @@ tty_wait(struct tty *tp, struct cv *cv)
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int error;
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int revokecnt = tp->t_revokecnt;
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#if 0
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/* XXX: /dev/console also picks up Giant. */
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tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
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#endif
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tty_lock_assert(tp, MA_OWNED);
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MPASS(!tty_gone(tp));
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error = cv_wait_sig(cv, tp->t_mtx);
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@ -1215,11 +1215,7 @@ tty_timedwait(struct tty *tp, struct cv *cv, int hz)
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int error;
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int revokecnt = tp->t_revokecnt;
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#if 0
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/* XXX: /dev/console also picks up Giant. */
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tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
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#endif
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tty_lock_assert(tp, MA_OWNED);
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MPASS(!tty_gone(tp));
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|
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error = cv_timedwait_sig(cv, tp->t_mtx, hz);
|
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@ -1662,6 +1658,10 @@ tty_hiwat_in_unblock(struct tty *tp)
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ttydevsw_inwakeup(tp);
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}
|
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|
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/*
|
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* TTY hooks interface.
|
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*/
|
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|
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static int
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ttyhook_defrint(struct tty *tp, char c, int flags)
|
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{
|
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@ -1745,6 +1745,84 @@ ttyhook_unregister(struct tty *tp)
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tty_rel_free(tp);
|
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}
|
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|
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/*
|
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* /dev/console handling.
|
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*/
|
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|
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static int
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ttyconsdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
|
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{
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struct tty *tp;
|
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|
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/* System has no console device. */
|
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if (dev_console_filename == NULL)
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return (ENXIO);
|
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|
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/* Look up corresponding TTY by device name. */
|
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sx_slock(&tty_list_sx);
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TAILQ_FOREACH(tp, &tty_list, t_list) {
|
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if (strcmp(dev_console_filename, tty_devname(tp)) == 0) {
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dev_console->si_drv1 = tp;
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break;
|
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}
|
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}
|
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sx_sunlock(&tty_list_sx);
|
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|
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/* System console has no TTY associated. */
|
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if (dev_console->si_drv1 == NULL)
|
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return (ENXIO);
|
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|
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return (ttydev_open(dev, oflags, devtype, td));
|
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}
|
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|
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static int
|
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ttyconsdev_write(struct cdev *dev, struct uio *uio, int ioflag)
|
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{
|
||||
|
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log_console(uio);
|
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|
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return (ttydev_write(dev, uio, ioflag));
|
||||
}
|
||||
|
||||
/*
|
||||
* /dev/console is a little different than normal TTY's. Unlike regular
|
||||
* TTY device nodes, this device node will not revoke the entire TTY
|
||||
* upon closure and all data written to it will be logged.
|
||||
*/
|
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static struct cdevsw ttyconsdev_cdevsw = {
|
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.d_version = D_VERSION,
|
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.d_open = ttyconsdev_open,
|
||||
.d_read = ttydev_read,
|
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.d_write = ttyconsdev_write,
|
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.d_ioctl = ttydev_ioctl,
|
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.d_kqfilter = ttydev_kqfilter,
|
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.d_poll = ttydev_poll,
|
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.d_mmap = ttydev_mmap,
|
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.d_name = "ttyconsdev",
|
||||
.d_flags = D_TTY,
|
||||
};
|
||||
|
||||
static void
|
||||
ttyconsdev_init(void *unused)
|
||||
{
|
||||
|
||||
dev_console = make_dev(&ttyconsdev_cdevsw, 0, UID_ROOT, GID_WHEEL,
|
||||
0600, "console");
|
||||
}
|
||||
|
||||
SYSINIT(tty, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyconsdev_init, NULL);
|
||||
|
||||
void
|
||||
ttyconsdev_select(const char *name)
|
||||
{
|
||||
|
||||
dev_console_filename = name;
|
||||
}
|
||||
|
||||
/*
|
||||
* Debugging routines.
|
||||
*/
|
||||
|
||||
#include "opt_ddb.h"
|
||||
#ifdef DDB
|
||||
#include <ddb/ddb.h>
|
||||
|
||||
@ -192,6 +192,9 @@ dev_t tty_udev(struct tty *tp);
|
||||
/* Status line printing. */
|
||||
void tty_info(struct tty *tp);
|
||||
|
||||
/* /dev/console selection. */
|
||||
void ttyconsdev_select(const char *name);
|
||||
|
||||
/* Pseudo-terminal hooks. */
|
||||
int pts_alloc_external(int fd, struct thread *td, struct file *fp,
|
||||
struct cdev *dev, const char *name);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user