common/io/sysmsg.c

	sysmsg.c revision da6c28aaf62fa55f0fdb8004aa40f88f23bf53f0
/*
 * 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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * System message redirection driver for Sun.
 *
 * Redirects system message output to the device designated as the underlying
 * "hardware" console, as given by the value of sysmvp.  The implementation
 * assumes that sysmvp denotes a STREAMS device; the assumption is justified
 * since consoles must be capable of effecting tty semantics.
 */

#include <sys/types.h>
#include <sys/kmem.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/vnode.h>
#include <sys/uio.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/session.h>
#include <sys/stream.h>
#include <sys/strsubr.h>
#include <sys/poll.h>
#include <sys/debug.h>
#include <sys/sysmsg_impl.h>
#include <sys/conf.h>
#include <sys/termios.h>
#include <sys/errno.h>
#include <sys/modctl.h>
#include <sys/pathname.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/consdev.h>
#include <sys/policy.h>

/*
 * internal functions
 */
static int sysmopen(dev_t *, int, int, cred_t *);
static int sysmclose(dev_t, int, int, cred_t *);
static int sysmread(dev_t, struct uio *, cred_t *);
static int sysmwrite(dev_t, struct uio *, cred_t *);
static int sysmioctl(dev_t, int, intptr_t, int, cred_t *, int *);
static int sysmpoll(dev_t, short, int, short *, struct pollhead **);
static int sysm_info(dev_info_t *, ddi_info_cmd_t, void *, void **);
static int sysm_attach(dev_info_t *, ddi_attach_cmd_t);
static int sysm_detach(dev_info_t *, ddi_detach_cmd_t);
static void bind_consadm_conf(char *);
static int checkarg(dev_t);

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

static struct cb_ops sysm_cb_ops = {

    sysmopen,       /* open */
    sysmclose,      /* close */
    nodev,          /* strategy */
    nodev,          /* print */
    nodev,          /* dump */
    sysmread,       /* read */
    sysmwrite,      /* write */
    sysmioctl,      /* ioctl */
    nodev,          /* devmap */
    nodev,          /* mmap */
    nodev,          /* segmap */
    sysmpoll,       /* poll */
    ddi_prop_op,        /* cb_prop_op */
    NULL,           /* streamtab  */
    D_NEW | D_MP,       /* Driver compatibility flag */
    CB_REV,         /* cb_rev */
    nodev,          /* aread */
    nodev           /* awrite */
};

static struct dev_ops sysm_ops = {

    DEVO_REV,       /* devo_rev, */
    0,          /* refcnt  */
    sysm_info,      /* info */
    nulldev,        /* identify */
    nulldev,        /* probe */
    sysm_attach,        /* attach */
    sysm_detach,        /* detach */
    nodev,          /* reset */
    &sysm_cb_ops,       /* driver operations */
    (struct bus_ops *)0,    /* bus operations */
    nulldev         /* power */

};

/*
 * Global variables associated with the console device:
 */

#define SYS_SYSMIN  0   /* sysmsg minor number */
#define SYS_MSGMIN  1   /* msglog minor number */
#define SYSPATHLEN  255 /* length of device path */

/*
 * Private driver state:
 */

#define MAXDEVS 5

typedef struct {
    dev_t   dca_devt;
    int dca_flags;
    vnode_t *dca_vp;
    krwlock_t   dca_lock;
    char    dca_name[SYSPATHLEN];
} devicecache_t;

/* list of dyn. + persist. config'ed dev's */
static devicecache_t sysmcache[MAXDEVS];
static kmutex_t dcvp_mutex;
static vnode_t  *dcvp = NULL;
static boolean_t sysmsg_opened;
static boolean_t msglog_opened;

/* flags for device cache */
#define SYSM_DISABLED   0x0
#define SYSM_ENABLED    0x1

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

static struct modldrv modldrv = {
    &mod_driverops, /* Type of module.  This one is a pseudo driver */
    "System message redirection (fanout) driver %I%",
    &sysm_ops,  /* driver ops */
};

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

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

int
_fini(void)
{
    return (mod_remove(&modlinkage));
}

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

/*
 * DDI glue routines
 */
static int
sysm_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
    int i;

    switch (cmd) {
    case DDI_ATTACH:
        ASSERT(sysm_dip == NULL);

        if (ddi_create_minor_node(devi, "sysmsg", S_IFCHR,
            SYS_SYSMIN, DDI_PSEUDO, NULL) == DDI_FAILURE ||
            ddi_create_minor_node(devi, "msglog", S_IFCHR,
            SYS_MSGMIN, DDI_PSEUDO, NULL) == DDI_FAILURE) {
            ddi_remove_minor_node(devi, NULL);
            return (DDI_FAILURE);
        }

        for (i = 0; i < MAXDEVS; i++) {
            rw_init(&sysmcache[i].dca_lock, NULL, RW_DRIVER, NULL);
        }

        sysm_dip = devi;
        return (DDI_SUCCESS);
    case DDI_SUSPEND:
    case DDI_PM_SUSPEND:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }
}

static int
sysm_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
    int i;

    switch (cmd) {
    case DDI_DETACH:
        ASSERT(sysm_dip == devi);

        for (i = 0; i < MAXDEVS; i++)
            rw_destroy(&sysmcache[i].dca_lock);

        ddi_remove_minor_node(devi, NULL);
        sysm_dip = NULL;
        return (DDI_SUCCESS);

    case DDI_SUSPEND:
    case DDI_PM_SUSPEND:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }

}

/* ARGSUSED */
static int
sysm_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
{
    int rval = DDI_FAILURE;
    minor_t instance;

    instance = getminor((dev_t)arg);

    switch (infocmd) {
    case DDI_INFO_DEVT2DEVINFO:
        if (sysm_dip != NULL &&
            (instance == SYS_SYSMIN || instance == SYS_MSGMIN)) {
            *result = sysm_dip;
            rval = DDI_SUCCESS;
        }
        break;

    case DDI_INFO_DEVT2INSTANCE:
        if (instance == SYS_SYSMIN || instance == SYS_MSGMIN) {
            *result = NULL;
            rval = DDI_SUCCESS;
        }
        break;

    default:
        break;
    }

    return (rval);
}

/*
 * Parse the contents of the buffer, and bind the named
 * devices as auxiliary consoles using our own ioctl routine.
 *
 * Comments begin with '#' and are terminated only by a newline
 * Device names begin with a '/', and are terminated by a newline,
 * space, '#' or tab.
 */
static void
parse_buffer(char *buf, ssize_t fsize)
{
    char *ebuf = buf + fsize;
    char *devname = NULL;
    int eatcomments = 0;

    while (buf < ebuf) {
        if (eatcomments) {
            if (*buf++ == '\n')
                eatcomments = 0;
            continue;
        }
        switch (*buf) {
        case '/':
            if (devname == NULL)
                devname = buf;
            break;
        case '#':
            eatcomments = 1;
            /*FALLTHROUGH*/
        case ' ':
        case '\t':
        case '\n':
            *buf = '\0';
            if (devname == NULL)
                break;
            (void) sysmioctl(NODEV, CIOCSETCONSOLE,
                (intptr_t)devname, FNATIVE|FKIOCTL|FREAD|FWRITE,
                kcred, NULL);
            devname = NULL;
            break;
        default:
            break;
        }
        buf++;
    }
}

#define CNSADM_BYTES_MAX    2000    /* XXX  nasty fixed size */

static void
bind_consadm_conf(char *path)
{
    struct vattr vattr;
    vnode_t *vp;
    void *buf;
    size_t size;
    ssize_t resid;
    int err = 0;

    if (vn_open(path, UIO_SYSSPACE, FREAD, 0, &vp, 0, 0) != 0)
        return;
    vattr.va_mask = AT_SIZE;
    if ((err = VOP_GETATTR(vp, &vattr, 0, kcred, NULL)) != 0) {
        cmn_err(CE_WARN, "sysmsg: getattr: '%s': error %d",
            path, err);
        goto closevp;
    }

    size = vattr.va_size > CNSADM_BYTES_MAX ?
        CNSADM_BYTES_MAX : (ssize_t)vattr.va_size;
    buf = kmem_alloc(size, KM_SLEEP);

    if ((err = vn_rdwr(UIO_READ, vp, buf, size, (offset_t)0,
        UIO_SYSSPACE, 0, (rlim64_t)0, kcred, &resid)) != 0)
        cmn_err(CE_WARN, "sysmsg: vn_rdwr: '%s': error %d",
            path, err);
    else
        parse_buffer(buf, size - resid);

    kmem_free(buf, size);
closevp:
    (void) VOP_CLOSE(vp, FREAD, 1, (offset_t)0, kcred, NULL);
    VN_RELE(vp);
}

/* ARGSUSED */
static int
sysmopen(dev_t *dev, int flag, int state, cred_t *cred)
{
    int i;
    vnode_t *vp;
    minor_t instance;
    static boolean_t initialized;

    instance = getminor(*dev);

    if (state != OTYP_CHR || (instance != 0 && instance != 1))
        return (ENXIO);

    mutex_enter(&dcvp_mutex);
    if ((dcvp == NULL) && (vn_open("/dev/console",
        UIO_SYSSPACE, FWRITE, 0, &dcvp, 0, 0) != 0)) {
        mutex_exit(&dcvp_mutex);
        return (ENXIO);
    }

    if (instance == SYS_SYSMIN)
        sysmsg_opened = B_TRUE;
    else
        msglog_opened = B_TRUE;

    if (!initialized) {
        bind_consadm_conf("/etc/consadm.conf");
        initialized = B_TRUE;
    }
    mutex_exit(&dcvp_mutex);

    for (i = 0; i < MAXDEVS; i++) {
        rw_enter(&sysmcache[i].dca_lock, RW_WRITER);
        if ((sysmcache[i].dca_flags & SYSM_ENABLED) &&
            sysmcache[i].dca_vp == NULL) {
            /*
             * 4196476 - FTRUNC was causing E10K to return EINVAL
             * on open
             */
            flag = flag & ~FTRUNC;
            /*
             * Open failures on the auxiliary consoles are
             * not returned because we don't care if some
             * subset get an error. We know the default console
             * is okay, and preserve the semantics of the
             * open for the default console.
             * Set NONBLOCK|NDELAY in case there's no carrier.
             */
            if (vn_open(sysmcache[i].dca_name, UIO_SYSSPACE,
                flag | FNONBLOCK | FNDELAY, 0, &vp, 0, 0) == 0)
                sysmcache[i].dca_vp = vp;
        }
        rw_exit(&sysmcache[i].dca_lock);
    }

    return (0);
}

/* ARGSUSED */
static int
sysmclose(dev_t dev, int flag, int state, cred_t *cred)
{
    int i;
    minor_t instance;

    ASSERT(dcvp != NULL);

    if (state != OTYP_CHR)
        return (ENXIO);

    instance = getminor(dev);

    mutex_enter(&dcvp_mutex);
    if (instance == SYS_SYSMIN)
        sysmsg_opened = B_FALSE;
    else
        msglog_opened = B_FALSE;

    if (sysmsg_opened || msglog_opened) {
        mutex_exit(&dcvp_mutex);
        return (0);
    }

    (void) VOP_CLOSE(dcvp, FWRITE, 1, (offset_t)0, kcred, NULL);
    VN_RELE(dcvp);
    dcvp = NULL;
    mutex_exit(&dcvp_mutex);

    /*
     * Close the auxiliary consoles, we're not concerned with
     * passing up the errors.
     */
    for (i = 0; i < MAXDEVS; i++) {
        rw_enter(&sysmcache[i].dca_lock, RW_WRITER);
        if (sysmcache[i].dca_vp != NULL) {
            (void) VOP_CLOSE(sysmcache[i].dca_vp, flag,
                1, (offset_t)0, cred, NULL);
            VN_RELE(sysmcache[i].dca_vp);
            sysmcache[i].dca_vp = NULL;
        }
        rw_exit(&sysmcache[i].dca_lock);
    }

    return (0);
}

/* Reads occur only on the default console */

/* ARGSUSED */
static int
sysmread(dev_t dev, struct uio *uio, cred_t *cred)
{
    ASSERT(dcvp != NULL);
    return (VOP_READ(dcvp, uio, 0, cred, NULL));
}

/* ARGSUSED */
static int
sysmwrite(dev_t dev, struct uio *uio, cred_t *cred)
{
    int i = 0;
    iovec_t uio_iov;
    struct uio  tuio;

    ASSERT(dcvp != NULL);
    ASSERT(uio != NULL);

    for (i = 0; i < MAXDEVS; i++) {
        rw_enter(&sysmcache[i].dca_lock, RW_READER);
        if (sysmcache[i].dca_vp != NULL &&
            (sysmcache[i].dca_flags & SYSM_ENABLED)) {
            tuio = *uio;
            uio_iov = *(uio->uio_iov);
            tuio.uio_iov = &uio_iov;
            (void) VOP_WRITE(sysmcache[i].dca_vp, &tuio, 0, cred,
                NULL);
        }
        rw_exit(&sysmcache[i].dca_lock);
    }
    return (VOP_WRITE(dcvp, uio, 0, cred, NULL));
}

/* ARGSUSED */
static int
sysmioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cred, int *rvalp)
{
    int rval = 0;
    int error = 0;
    size_t  size = 0;
    int i;
    char    *infop;
    char    found = 0;
    dev_t   newdevt = (dev_t)NODEV; /* because 0 == /dev/console */
    vnode_t *vp;

    switch (cmd) {
    case CIOCGETCONSOLE:
        /* Sum over the number of enabled devices */
        for (i = 0; i < MAXDEVS; i++) {
            if (sysmcache[i].dca_flags & SYSM_ENABLED)
                /* list is space separated, followed by NULL */
                size += strlen(sysmcache[i].dca_name) + 1;
        }
        if (size == 0)
            return (0);
        break;
    case CIOCSETCONSOLE:
    case CIOCRMCONSOLE:
        size = sizeof (sysmcache[0].dca_name);
        break;
    case CIOCTTYCONSOLE:
    {
        dev_t   d;
        dev32_t d32;
        extern dev_t rwsconsdev, rconsdev, uconsdev;
        proc_t  *p;

        if (drv_getparm(UPROCP, &p) != 0)
            return (ENODEV);
        else
            d = cttydev(p);
        /*
         * If the controlling terminal is the real
         * or workstation console device, map to what the
         * user thinks is the console device.
         */
        if (d == rwsconsdev || d == rconsdev)
            d = uconsdev;
        if ((flag & FMODELS) != FNATIVE) {
            if (!cmpldev(&d32, d))
                return (EOVERFLOW);
            if (ddi_copyout(&d32, (caddr_t)arg, sizeof (d32),
                flag))
                return (EFAULT);
        } else {
            if (ddi_copyout(&d, (caddr_t)arg, sizeof (d), flag))
                return (EFAULT);
        }
        return (0);
    }
    default:
        /* everything else is sent to the console device */
        return (VOP_IOCTL(dcvp, cmd, arg, flag, cred, rvalp, NULL));
    }

    if ((rval = secpolicy_console(cred)) != 0)
        return (EPERM);

    infop = kmem_alloc(size, KM_SLEEP);
    if (flag & FKIOCTL)
        error = copystr((caddr_t)arg, infop, size, NULL);
    else
        error = copyinstr((caddr_t)arg, infop, size, NULL);

    if (error) {
        switch (cmd) {
        case CIOCGETCONSOLE:
            /*
             * If the buffer is null, then return a byte count
             * to user land.
             */
            *rvalp = size;
            goto err_exit;
        default:
            rval = EFAULT;
            goto err_exit;
        }
    }

    if (infop[0] != NULL) {
        if ((rval = lookupname(infop, UIO_SYSSPACE, FOLLOW,
            NULLVPP, &vp)) == 0) {
            if (vp->v_type != VCHR) {
                VN_RELE(vp);
                rval = EINVAL;
                goto err_exit;
            }
            newdevt = vp->v_rdev;
            VN_RELE(vp);
        } else
            goto err_exit;
    }

    switch (cmd) {
    case CIOCGETCONSOLE:
        /*
         * Return the list of device names that are enabled.
         */
        for (i = 0; i < MAXDEVS; i++) {
            rw_enter(&sysmcache[i].dca_lock, RW_READER);
            if (sysmcache[i].dca_flags & SYSM_ENABLED) {
                if (infop[0] != NULL)
                    (void) strcat(infop, " ");
                (void) strcat(infop, sysmcache[i].dca_name);
            }
            rw_exit(&sysmcache[i].dca_lock);
        }
        if (rval == 0 && copyoutstr(infop, (void *)arg, size, NULL))
            rval = EFAULT;
        break;

    case CIOCSETCONSOLE:
        if ((rval = checkarg(newdevt)) != 0)
            break;
        /*
         * The device does not have to be open or disabled to
         * perform the set console.
         */
        for (i = 0; i < MAXDEVS; i++) {
            rw_enter(&sysmcache[i].dca_lock, RW_WRITER);
            if (sysmcache[i].dca_devt == newdevt &&
                (sysmcache[i].dca_flags & SYSM_ENABLED)) {
                (void) strcpy(sysmcache[i].dca_name, infop);
                rval = EEXIST;
                rw_exit(&sysmcache[i].dca_lock);
                break;
            } else if (sysmcache[i].dca_devt == newdevt &&
                sysmcache[i].dca_flags == SYSM_DISABLED) {
                sysmcache[i].dca_flags |= SYSM_ENABLED;
                (void) strcpy(sysmcache[i].dca_name, infop);
                rw_exit(&sysmcache[i].dca_lock);
                found = 1;
                break;
            } else if (sysmcache[i].dca_devt == 0) {
                ASSERT(sysmcache[i].dca_vp == NULL &&
                sysmcache[i].dca_flags == SYSM_DISABLED);
                (void) strcpy(sysmcache[i].dca_name, infop);
                sysmcache[i].dca_flags = SYSM_ENABLED;
                sysmcache[i].dca_devt = newdevt;
                rw_exit(&sysmcache[i].dca_lock);
                found = 1;
                break;
            }
            rw_exit(&sysmcache[i].dca_lock);
        }
        if (found == 0 && rval == 0)
            rval = ENOENT;
        break;

    case CIOCRMCONSOLE:
        for (i = 0; i < MAXDEVS; i++) {
            rw_enter(&sysmcache[i].dca_lock, RW_WRITER);
            if (sysmcache[i].dca_devt == newdevt) {
                sysmcache[i].dca_flags = SYSM_DISABLED;
                sysmcache[i].dca_name[0] = '\0';
                rw_exit(&sysmcache[i].dca_lock);
                found = 1;
                break;
            }
            rw_exit(&sysmcache[i].dca_lock);
        }
        if (found == 0)
            rval = ENOENT;
        break;

    default:
        break;
    }

err_exit:
    kmem_free(infop, size);
    return (rval);
}

/* As with the read, we poll only the default console */

/* ARGSUSED */
static int
sysmpoll(dev_t dev, short events, int anyyet, short *reventsp,
    struct pollhead **phpp)
{
    return (VOP_POLL(dcvp, events, anyyet, reventsp, phpp, NULL));
}

/* Sanity check that the device is good */
static int
checkarg(dev_t devt)
{
    int rval = 0;
    dev_t sysmsg_dev, msglog_dev;
    extern dev_t rwsconsdev, rconsdev, uconsdev;

    if (devt == rconsdev || devt == rwsconsdev || devt == uconsdev) {
        rval = EBUSY;
    } else {
        sysmsg_dev = makedevice(ddi_driver_major(sysm_dip), SYS_SYSMIN);
        msglog_dev = makedevice(ddi_driver_major(sysm_dip), SYS_MSGMIN);
        if (devt == sysmsg_dev || devt == msglog_dev)
            rval = EINVAL;
    }

    return (rval);
}