remove unnecessary offset_t casts of 0

[unleashed.git] / usr / src / uts / common / io / cons.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1982, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2015, Joyent, Inc. All rights reserved.
 */

/*
 * Indirect console driver for Sun.
 *
 * Redirects all I/O to the device designated as the underlying "hardware"
 * console, as given by the value of rconsvp.  The implementation assumes that
 * rconsvp denotes a STREAMS device; the assumption is justified since
 * consoles must be capable of effecting tty semantics.
 *
 * rconsvp is set in autoconf.c:consconfig(), based on information obtained
 * from the EEPROM.
 *
 * XXX: The driver still needs to be converted to use ANSI C consistently
 *      throughout.
 */

#include <sys/types.h>
#include <sys/open.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/signal.h>
#include <sys/cred.h>
#include <sys/user.h>
#include <sys/proc.h>
#include <sys/disp.h>
#include <sys/file.h>
#include <sys/taskq.h>
#include <sys/log.h>
#include <sys/vnode.h>
#include <sys/uio.h>
#include <sys/stat.h>
#include <sys/limits.h>

#include <sys/console.h>
#include <sys/consdev.h>

#include <sys/stream.h>
#include <sys/strsubr.h>
#include <sys/poll.h>

#include <sys/debug.h>

#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/vt.h>

static int cnopen(dev_t *, int, int, struct cred *);
static int cnclose(dev_t, int, int, struct cred *);
static int cnread(dev_t, struct uio *, struct cred *);
static int cnwrite(dev_t, struct uio *, struct cred *);
static int cnioctl(dev_t, int, intptr_t, int, struct cred *, int *);
static int cnpoll(dev_t, short, int, short *, struct pollhead **);
static int cn_info(dev_info_t *, ddi_info_cmd_t, void *, void **);
static int cn_attach(dev_info_t *, ddi_attach_cmd_t);
static int cn_detach(dev_info_t *, ddi_detach_cmd_t);

static dev_info_t *cn_dip;              /* private copy of devinfo pointer */

static struct cb_ops cn_cb_ops = {

        cnopen,                 /* open */
        cnclose,                /* close */
        nodev,                  /* strategy */
        nodev,                  /* print */
        nodev,                  /* dump */
        cnread,                 /* read */
        cnwrite,                /* write */
        cnioctl,                /* ioctl */
        nodev,                  /* devmap */
        nodev,                  /* mmap */
        nodev,                  /* segmap */
        cnpoll,                 /* poll */
        ddi_prop_op,            /* cb_prop_op */
        0,                      /* streamtab  */
        D_NEW | D_MP            /* Driver compatibility flag */

};

static struct dev_ops cn_ops = {

        DEVO_REV,               /* devo_rev, */
        0,                      /* refcnt  */
        cn_info,                /* info */
        nulldev,                /* identify */
        nulldev,                /* probe */
        cn_attach,              /* attach */
        cn_detach,              /* detach */
        nodev,                  /* reset */
        &cn_cb_ops,             /* driver operations */
        NULL,   /* bus operations */
        NULL,                   /* power */
        ddi_quiesce_not_needed,         /* quiesce */

};

/*
 * Global variables associated with the console device:
 *
 * XXX: There are too many of these!
 * moved to space.c to become resident in the kernel so that cons
 * can be loadable.
 */

extern dev_t    rconsdev;       /* "hardware" console */
extern vnode_t  *rconsvp;       /* pointer to vnode for that device */

/*
 * XXX: consulted in prsubr.c, for /proc entry point for obtaining ps info.
 */
extern dev_t    uconsdev;       /* What the user thinks is the console device */

/*
 * Private driver state:
 */

/*
 * The underlying console device potentially can be opened through (at least)
 * two paths: through this driver and through the underlying device's driver.
 * To ensure that reference counts are meaningful and therefore that close
 * routines are called at the right time, it's important to make sure that
 * rconsvp's s_count field (i.e., the count on the underlying device) never
 * has a contribution of more than one through this driver, regardless of how
 * many times this driver's been opened.  rconsopen keeps track of the
 * necessary information to ensure this property.
 */
static uint_t   rconsopen;


#include <sys/types.h>
#include <sys/conf.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/modctl.h>


extern int nodev(), nulldev();
extern int dseekneg_flag;
extern struct mod_ops mod_driverops;
extern struct dev_ops cn_ops;

/*
 * Module linkage information for the kernel.
 */

static struct modldrv modldrv = {
        &mod_driverops, /* Type of module.  This one is a pseudo driver */
        "Console redirection driver",
        &cn_ops,        /* driver ops */
};

static struct modlinkage modlinkage = {
        MODREV_1,
        &modldrv,
        NULL
};

int
_init(void)
{
        return (mod_install(&modlinkage));
}

int
_fini(void)
{
        return (EBUSY);
}

int
_info(struct modinfo *modinfop)
{
        return (mod_info(&modlinkage, modinfop));
}

/*
 * DDI glue routines
 */
static int
cn_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
        if (cmd != DDI_ATTACH)
                return (DDI_FAILURE);

        if (ddi_create_minor_node(devi, "syscon", S_IFCHR,
            0, DDI_PSEUDO, 0) == DDI_FAILURE) {
                return (DDI_FAILURE);
        }
        if (ddi_create_minor_node(devi, "systty", S_IFCHR,
            0, DDI_PSEUDO, 0) == DDI_FAILURE) {
                ddi_remove_minor_node(devi, NULL);
                return (DDI_FAILURE);
        }
        if (ddi_create_minor_node(devi, "console", S_IFCHR,
            0, DDI_PSEUDO, 0) == DDI_FAILURE) {
                ddi_remove_minor_node(devi, NULL);
                return (DDI_FAILURE);
        }

        cn_dip = devi;
        return (DDI_SUCCESS);
}

static int
cn_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
        if (cmd != DDI_DETACH)
                return (DDI_FAILURE);
        ddi_remove_minor_node(devi, NULL);
        uconsdev = NODEV;
        return (DDI_SUCCESS);
}

/* ARGSUSED */
static int
cn_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
{
        int error = DDI_FAILURE;

        switch (infocmd) {
        case DDI_INFO_DEVT2DEVINFO:
                if (getminor((dev_t)arg) == 0 && cn_dip != NULL) {
                        *result = (void *) cn_dip;
                        error = DDI_SUCCESS;
                }
                break;

        case DDI_INFO_DEVT2INSTANCE:
                if (getminor((dev_t)arg) == 0) {
                        *result = NULL;
                        error = DDI_SUCCESS;
                }
                break;

        default:
                break;
        }

        return (error);
}

/*
 * XXX  Caution: before allowing more than 256 minor devices on the
 *      console, make sure you understand the 'compatibility' hack
 *      in ufs_iget() that translates old dev_t's to new dev_t's.
 *      See bugid 1098104 for the sordid details.
 */

/* ARGSUSED */
static int
cnopen(dev_t *dev, int flag, int state, struct cred *cred)
{
        int     err;
        static int      been_here;
        vnode_t *vp = rconsvp;

        ASSERT(cred != NULL);

        if (rconsvp == NULL)
                return (0);

        /*
         * Enable virtual console I/O for console logging if needed.
         */
        if (vsconsvp != NULL && vsconsvp->v_stream == NULL) {
                if (fop_open(&vsconsvp, FREAD | FWRITE, cred, NULL) != 0) {
                        cmn_err(CE_WARN, "cnopen: failed to open vsconsvp "
                            "for virtual console logging");
                }
        }

        /*
         * XXX: Clean up inactive PIDs from previous opens if any.
         * These would have been created as a result of an I_SETSIG
         * issued against console.  This is a workaround, and
         * console driver must be correctly redesigned not to need
         * this hook.
         */
        if (vp->v_stream) {
                str_cn_clean(vp);
        }

        /*
         * XXX: Set hook to tell /proc about underlying console.  (There's
         *      gotta be a better way...)
         */
        if (state != OTYP_CHR || getminor(*dev) != 0)
                return (ENXIO);
        if (been_here == 0) {
                uconsdev = *dev;
                been_here = 1;
                if (vn_open("/dev/console", UIO_SYSSPACE, FWRITE | FNOCTTY,
                    0, &console_vnode, 0, 0) == 0)
                        console_taskq = taskq_create("console_taskq",
                            1, maxclsyspri - 1, LOG_LOWAT / LOG_MSGSIZE,
                            LOG_HIWAT / LOG_MSGSIZE, TASKQ_PREPOPULATE);
        }

        if ((err = fop_open(&vp, flag, cred, NULL)) != 0)
                return (err);

        /*
         * The underlying driver is not allowed to have cloned itself
         * for this open.
         */
        if (vp != rconsvp) {
                /*
                 * It might happen that someone set rconsvp to NULL
                 * whilst we were in the middle of the open.
                 */
                if (rconsvp == NULL) {
                        (void) fop_close(vp, flag, 1, 0, cred, NULL);
                        return (0);
                }
                cmn_err(CE_PANIC, "cnopen: cloned open");
        }

        rconsopen++;

        return (0);
}

/* ARGSUSED */
static int
cnclose(dev_t dev, int flag, int state, struct cred *cred)
{
        int     err = 0;
        vnode_t *vp;

        /*
         * Since this is the _last_ close, it's our last chance to close the
         * underlying device.  (Note that if someone else has the underlying
         * hardware console device open, we won't get here, since spec_close
         * will see s_count > 1.)
         */
        if (state != OTYP_CHR)
                return (ENXIO);

        if (rconsvp == NULL)
                return (0);

        while ((rconsopen != 0) && ((vp = rconsvp) != NULL)) {
                err = fop_close(vp, flag, 1, 0, cred, NULL);
                if (!err) {
                        rconsopen--;
                }
        }
        return (err);
}

/* ARGSUSED */
static int
cnread(dev_t dev, struct uio *uio, struct cred *cred)
{
        kcondvar_t      sleep_forever;
        kmutex_t        sleep_forever_mutex;

        if (rconsvp == NULL) {
                /*
                 * Go to sleep forever.  This seems like the least
                 * harmful thing to do if there's no console.
                 * EOF might be better if we're ending up single-user
                 * mode.
                 */
                cv_init(&sleep_forever, NULL, CV_DRIVER, NULL);
                mutex_init(&sleep_forever_mutex, NULL, MUTEX_DRIVER, NULL);
                mutex_enter(&sleep_forever_mutex);
                (void) cv_wait_sig(&sleep_forever, &sleep_forever_mutex);
                mutex_exit(&sleep_forever_mutex);
                return (EIO);
        }

        if (rconsvp->v_stream != NULL)
                return (strread(rconsvp, uio, cred));
        else
                return (cdev_read(rconsdev, uio, cred));
}

/* ARGSUSED */
static int
cnwrite(dev_t dev, struct uio *uio, struct cred *cred)
{
        if (rconsvp == NULL) {
                uio->uio_resid = 0;
                return (0);
        }

        /*
         * Output to virtual console for logging if enabled.
         */
        if (vsconsvp != NULL && vsconsvp->v_stream != NULL) {
                struiod_t uiod;
                struct iovec buf[IOV_MAX_STACK];
                int iovlen = 0;

                if (uio->uio_iovcnt > IOV_MAX_STACK) {
                        iovlen = uio->uio_iovcnt * sizeof (iovec_t);
                        uiod.d_iov = kmem_alloc(iovlen, KM_SLEEP);
                } else {
                        uiod.d_iov = buf;
                }

                /*
                 * strwrite modifies uio so need to make copy.
                 */
                (void) uiodup(uio, &uiod.d_uio, uiod.d_iov, uio->uio_iovcnt);

                (void) strwrite(vsconsvp, &uiod.d_uio, cred);
                if (iovlen != 0)
                        kmem_free(uiod.d_iov, iovlen);
        }

        if (rconsvp->v_stream != NULL)
                return (strwrite(rconsvp, uio, cred));
        else
                return (cdev_write(rconsdev, uio, cred));
}

/* ARGSUSED */
static int
cnprivateioc(dev_t dev, int cmd, intptr_t arg, int flag, struct cred *cred,
    int *rvalp)
{

        /* currently we only support one ioctl */
        if (cmd != CONS_GETTERM)
                return (EINVAL);

        /* Confirm iwscn is immediate target of cn redirection */
        if (rconsvp != wsconsvp)
                return (ENODEV);

        /*
         * If the redirection client is not wc, it should return
         * error upon receiving the CONS_GETTERM ioctl.
         *
         * if it is wc, we know that the target supports the CONS_GETTERM
         * ioctl, which very conviently has the exact same data
         * format as this ioctl...  so let's just pass it on.
         */
        return (cdev_ioctl(rconsdev, CONS_GETTERM, arg, flag, cred, rvalp));
}

/* ARGSUSED */
static int
cnioctl(dev_t dev, int cmd, intptr_t arg, int flag, struct cred *cred,
    int *rvalp)
{
        if (rconsvp == NULL)
                return (0);

        /*
         * In wc, VT_SET_CONSUSER which comes from minor node 0
         * has two sources -- either /dev/console or /dev/vt/0 .
         * We need a way to differentiate them, so here we
         * change VT_SET_CONSUSER to a private VT_RESET_CONSUSER
         * ioctl.
         */
        if (cmd == VT_SET_CONSUSER)
                cmd = VT_RESET_CONSUSER;

        if ((cmd & _CNIOC_MASK) == _CNIOC)
                return (cnprivateioc(dev, cmd, arg, flag, cred, rvalp));

        if (rconsvp->v_stream != NULL)
                return (strioctl(rconsvp, cmd, arg, flag, U_TO_K,
                    cred, rvalp));

        return (cdev_ioctl(rconsdev, cmd, arg, flag, cred, rvalp));
}

/* ARGSUSED */
static int
cnpoll(dev_t dev, short events, int anyyet, short *reventsp,
    struct pollhead **phpp)
{
        if (rconsvp == NULL)
                return (nochpoll(dev, events, anyyet, reventsp, phpp));

        if (rconsvp->v_stream != NULL)
                return (strpoll(rconsvp->v_stream, events, anyyet, reventsp,
                    phpp));
        else
                return (cdev_poll(rconsdev, events, anyyet, reventsp, phpp));
}