common/syscall/uadmin.c

	uadmin.c revision facf4a8d7b59fde89a8662b4f4c73a758e6c402c
/*
 * 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 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

#include <sys/param.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/swap.h>
#include <sys/file.h>
#include <sys/proc.h>
#include <sys/var.h>
#include <sys/uadmin.h>
#include <sys/signal.h>
#include <sys/time.h>
#include <vm/seg_kmem.h>
#include <sys/modctl.h>
#include <sys/callb.h>
#include <sys/dumphdr.h>
#include <sys/debug.h>
#include <sys/ftrace.h>
#include <sys/cmn_err.h>
#include <sys/panic.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/policy.h>
#include <sys/zone.h>

/*
 * Administrivia system call.  We provide this in two flavors: one for calling
 * from the system call path (uadmin), and the other for calling from elsewhere
 * within the kernel (kadmin).  Callers must beware that certain uadmin cmd
 * values (specifically A_SWAPCTL) are only supported by uadmin and not kadmin.
 */

extern ksema_t fsflush_sema;
kmutex_t ualock;

int sys_shutdown = 0;

/*
 * Kill all user processes in said zone.  A special argument of ALL_ZONES is
 * passed in when the system as a whole is shutting down.  The lack of per-zone
 * process lists is likely to make the following a performance bottleneck on a
 * system with many zones.
 */
void
killall(zoneid_t zoneid)
{
    proc_t *p;

    ASSERT(zoneid != GLOBAL_ZONEID);
    /*
     * Kill all processes except kernel daemons and ourself.
     * Make a first pass to stop all processes so they won't
     * be trying to restart children as we kill them.
     */
    mutex_enter(&pidlock);
    for (p = practive; p != NULL; p = p->p_next) {
        if ((zoneid == ALL_ZONES || p->p_zone->zone_id == zoneid) &&
            p->p_exec != NULLVP &&  /* kernel daemons */
            p->p_as != &kas &&
            p->p_stat != SZOMB) {
            mutex_enter(&p->p_lock);
            p->p_flag |= SNOWAIT;
            sigtoproc(p, NULL, SIGSTOP);
            mutex_exit(&p->p_lock);
        }
    }
    p = practive;
    while (p != NULL) {
        if ((zoneid == ALL_ZONES || p->p_zone->zone_id == zoneid) &&
            p->p_exec != NULLVP &&  /* kernel daemons */
            p->p_as != &kas &&
            p->p_stat != SIDL &&
            p->p_stat != SZOMB) {
            mutex_enter(&p->p_lock);
            if (sigismember(&p->p_sig, SIGKILL)) {
                mutex_exit(&p->p_lock);
                p = p->p_next;
            } else {
                sigtoproc(p, NULL, SIGKILL);
                mutex_exit(&p->p_lock);
                (void) cv_timedwait(&p->p_srwchan_cv, &pidlock,
                    lbolt + hz);
                p = practive;
            }
        } else {
            p = p->p_next;
        }
    }
    mutex_exit(&pidlock);
}

int
kadmin(int cmd, int fcn, void *mdep, cred_t *credp)
{
    int error = 0;
    int locked = 0;
    char *buf;
    size_t buflen = 0;
    boolean_t invoke_cb = B_FALSE;

    /*
     * We might be called directly by the kernel's fault-handling code, so
     * we can't assert that the caller is in the global zone.
     */

    /*
     * Make sure that cmd is one of the valid <sys/uadmin.h> command codes
     * and that we have appropriate privileges for this action.
     */
    switch (cmd) {
    case A_FTRACE:
    case A_SHUTDOWN:
    case A_REBOOT:
    case A_REMOUNT:
    case A_FREEZE:
    case A_DUMP:
        if (secpolicy_sys_config(credp, B_FALSE) != 0)
            return (EPERM);
        break;

    default:
        return (EINVAL);
    }

    /*
     * Serialize these operations on ualock.  If it is held, just return
     * as if successful since the system will soon reset or remount.
     */
    if (cmd == A_SHUTDOWN || cmd == A_REBOOT || cmd == A_REMOUNT) {
        if (!mutex_tryenter(&ualock))
            return (0);
        locked = 1;
    }

    switch (cmd) {
    case A_SHUTDOWN:
    {
        proc_t *p = ttoproc(curthread);

        /*
         * Release (almost) all of our own resources if we are called
         * from a user context, however if we are calling kadmin() from
         * a kernel context then we do not release these resources.
         */
        if (p != &p0) {
            proc_is_exiting(p);
            if ((error = exitlwps(0)) != 0)
                return (error);
            mutex_enter(&p->p_lock);
            p->p_flag |= SNOWAIT;
            sigfillset(&p->p_ignore);
            curthread->t_lwp->lwp_cursig = 0;
            curthread->t_lwp->lwp_extsig = 0;
            if (p->p_exec) {
                vnode_t *exec_vp = p->p_exec;
                p->p_exec = NULLVP;
                mutex_exit(&p->p_lock);
                VN_RELE(exec_vp);
            } else {
                mutex_exit(&p->p_lock);
            }

            pollcleanup();
            closeall(P_FINFO(curproc));
            relvm();

        } else {
            /*
             * Reset t_cred if not set because much of the
             * filesystem code depends on CRED() being valid.
             */
            if (curthread->t_cred == NULL)
                curthread->t_cred = kcred;
        }

        /* indicate shutdown in progress */
        sys_shutdown = 1;

        /*
         * Communcate that init shouldn't be restarted.
         */
        zone_shutdown_global();

        killall(ALL_ZONES);
        /*
         * If we are calling kadmin() from a kernel context then we
         * do not release these resources.
         */
        if (ttoproc(curthread) != &p0) {
            VN_RELE(u.u_cdir);
            if (u.u_rdir)
                VN_RELE(u.u_rdir);
            if (u.u_cwd)
                refstr_rele(u.u_cwd);

            u.u_cdir = rootdir;
            u.u_rdir = NULL;
            u.u_cwd = NULL;
        }

        /*
         * Allow the reboot/halt/poweroff code a chance to do
         * anything it needs to whilst we still have filesystems
         * mounted, like loading any modules necessary for later
         * performing the actual poweroff.
         */
        if ((mdep != NULL) && (*(char *)mdep == '/')) {
            buf = i_convert_boot_device_name(mdep, NULL, &buflen);
            mdpreboot(cmd, fcn, buf);
        } else
            mdpreboot(cmd, fcn, mdep);

        /*
         * Allow fsflush to finish running and then prevent it
         * from ever running again so that vfs_unmountall() and
         * vfs_syncall() can acquire the vfs locks they need.
         */
        sema_p(&fsflush_sema);
        (void) callb_execute_class(CB_CL_UADMIN_PRE_VFS, NULL);

        vfs_unmountall();
        (void) VFS_MOUNTROOT(rootvfs, ROOT_UNMOUNT);
        vfs_syncall();

        dump_ereports();
        dump_messages();

        invoke_cb = B_TRUE;

        /* FALLTHROUGH */
    }

    case A_REBOOT:
        if ((mdep != NULL) && (*(char *)mdep == '/')) {
            buf = i_convert_boot_device_name(mdep, NULL, &buflen);
            mdboot(cmd, fcn, buf, invoke_cb);
        } else
            mdboot(cmd, fcn, mdep, invoke_cb);
        /* no return expected */
        break;

    case A_REMOUNT:
        (void) VFS_MOUNTROOT(rootvfs, ROOT_REMOUNT);
        break;

    case A_FREEZE:
    {
        /* XXX: declare in some header file */
        extern int cpr(int);

        if (modload("misc", "cpr") == -1)
            return (ENOTSUP);
        error = cpr(fcn);
        break;
    }

    case A_FTRACE:
    {
        switch (fcn) {
        case AD_FTRACE_START:
            (void) FTRACE_START();
            break;
        case AD_FTRACE_STOP:
            (void) FTRACE_STOP();
            break;
        default:
            error = EINVAL;
        }
        break;
    }

    case A_DUMP:
    {
        if (fcn == AD_NOSYNC) {
            in_sync = 1;
            break;
        }

        panic_bootfcn = fcn;
        panic_forced = 1;

        if ((mdep != NULL) && (*(char *)mdep == '/')) {
            panic_bootstr = i_convert_boot_device_name(mdep,
                NULL, &buflen);
        } else
            panic_bootstr = mdep;

        panic("forced crash dump initiated at user request");
        /*NOTREACHED*/
    }

    default:
        error = EINVAL;
    }

    if (locked)
        mutex_exit(&ualock);

    return (error);
}

int
uadmin(int cmd, int fcn, uintptr_t mdep)
{
    int error = 0, rv = 0;
    size_t nbytes = 0;
    cred_t *credp = CRED();
    char *bootargs = NULL;

    /*
     * The swapctl system call doesn't have its own entry point: it uses
     * uadmin as a wrapper so we just call it directly from here.
     */
    if (cmd == A_SWAPCTL) {
        if (get_udatamodel() == DATAMODEL_NATIVE)
            error = swapctl(fcn, (void *)mdep, &rv);
#if defined(_SYSCALL32_IMPL)
        else
            error = swapctl32(fcn, (void *)mdep, &rv);
#endif /* _SYSCALL32_IMPL */
        return (error ? set_errno(error) : rv);
    }

    /*
     * Certain subcommands intepret a non-NULL mdep value as a pointer to
     * a boot string.  We pull that in as bootargs, if applicable.
     */
    if (mdep != NULL &&
        (cmd == A_SHUTDOWN || cmd == A_REBOOT || cmd == A_DUMP)) {
        bootargs = kmem_zalloc(BOOTARGS_MAX, KM_SLEEP);
        if ((error = copyinstr((const char *)mdep, bootargs,
            BOOTARGS_MAX, &nbytes)) != 0) {
            kmem_free(bootargs, BOOTARGS_MAX);
            return (set_errno(error));
        }
    }

    /*
     * Invoke the appropriate kadmin() routine.
     */
    if (getzoneid() != GLOBAL_ZONEID)
        error = zone_kadmin(cmd, fcn, bootargs, credp);
    else
        error = kadmin(cmd, fcn, bootargs, credp);

    if (bootargs != NULL)
        kmem_free(bootargs, BOOTARGS_MAX);
    return (error ? set_errno(error) : 0);
}