[mirror_zfs-debian.git] / lib / libzpool / kernel.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) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <assert.h>
#include <fcntl.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <zlib.h>
#include <sys/signal.h>
#include <sys/spa.h>
#include <sys/stat.h>
#include <sys/processor.h>
#include <sys/zfs_context.h>
#include <sys/utsname.h>
#include <sys/time.h>
#include <sys/systeminfo.h>

/*
 * Emulation of kernel services in userland.
 */

int aok;
uint64_t physmem;
vnode_t *rootdir = (vnode_t *)0xabcd1234;
char hw_serial[HW_HOSTID_LEN];

struct utsname utsname = {
        "userland", "libzpool", "1", "1", "na"
};

/* this only exists to have its address taken */
struct proc p0;

/*
 * =========================================================================
 * threads
 * =========================================================================
 */

pthread_cond_t kthread_cond = PTHREAD_COND_INITIALIZER;
pthread_mutex_t kthread_lock = PTHREAD_MUTEX_INITIALIZER;
pthread_key_t kthread_key;
int kthread_nr = 0;

static void
thread_init(void)
{
        kthread_t *kt;

        VERIFY3S(pthread_key_create(&kthread_key, NULL), ==, 0);

        /* Create entry for primary kthread */
        kt = umem_zalloc(sizeof(kthread_t), UMEM_NOFAIL);
        kt->t_tid = pthread_self();
        kt->t_func = NULL;

        VERIFY3S(pthread_setspecific(kthread_key, kt), ==, 0);

        /* Only the main thread should be running at the moment */
        ASSERT3S(kthread_nr, ==, 0);
        kthread_nr = 1;
}

static void
thread_fini(void)
{
        kthread_t *kt = curthread;

        ASSERT(pthread_equal(kt->t_tid, pthread_self()));
        ASSERT3P(kt->t_func, ==, NULL);

        umem_free(kt, sizeof(kthread_t));

        /* Wait for all threads to exit via thread_exit() */
        VERIFY3S(pthread_mutex_lock(&kthread_lock), ==, 0);

        kthread_nr--; /* Main thread is exiting */

        while (kthread_nr > 0)
                VERIFY3S(pthread_cond_wait(&kthread_cond, &kthread_lock), ==,
                    0);

        ASSERT3S(kthread_nr, ==, 0);
        VERIFY3S(pthread_mutex_unlock(&kthread_lock), ==, 0);

        VERIFY3S(pthread_key_delete(kthread_key), ==, 0);
}

kthread_t *
zk_thread_current(void)
{
        kthread_t *kt = pthread_getspecific(kthread_key);

        ASSERT3P(kt, !=, NULL);

        return kt;
}

void *
zk_thread_helper(void *arg)
{
        kthread_t *kt = (kthread_t *) arg;

        VERIFY3S(pthread_setspecific(kthread_key, kt), ==, 0);

        VERIFY3S(pthread_mutex_lock(&kthread_lock), ==, 0);
        kthread_nr++;
        VERIFY3S(pthread_mutex_unlock(&kthread_lock), ==, 0);

        kt->t_tid = pthread_self();
        ((thread_func_arg_t) kt->t_func)(kt->t_arg);

        /* Unreachable, thread must exit with thread_exit() */
        abort();

        return NULL;
}

kthread_t *
zk_thread_create(caddr_t stk, size_t stksize, thread_func_t func, void *arg,
              size_t len, proc_t *pp, int state, pri_t pri)
{
        kthread_t *kt;
        pthread_attr_t attr;
        size_t stack;

        ASSERT3S(state & ~TS_RUN, ==, 0);

        kt = umem_zalloc(sizeof(kthread_t), UMEM_NOFAIL);
        kt->t_func = func;
        kt->t_arg = arg;

        /*
         * The Solaris kernel stack size is 24k for x86/x86_64.
         * The Linux kernel stack size is 8k for x86/x86_64.
         *
         * We reduce the default stack size in userspace, to ensure
         * we observe stack overruns in user space as well as in
         * kernel space.  PTHREAD_STACK_MIN is the minimum stack
         * required for a NULL procedure in user space and is added
         * in to the stack requirements.
         *
         * Some buggy NPTL threading implementations include the
         * guard area within the stack size allocations.  In
         * this case we allocate an extra page to account for the
         * guard area since we only have two pages of usable stack
         * on Linux.
         */

        stack = PTHREAD_STACK_MIN + MAX(stksize, STACK_SIZE) +
                        EXTRA_GUARD_BYTES;

        VERIFY3S(pthread_attr_init(&attr), ==, 0);
        VERIFY3S(pthread_attr_setstacksize(&attr, stack), ==, 0);
        VERIFY3S(pthread_attr_setguardsize(&attr, PAGESIZE), ==, 0);

        VERIFY3S(pthread_create(&kt->t_tid, &attr, &zk_thread_helper, kt),
            ==, 0);

        VERIFY3S(pthread_attr_destroy(&attr), ==, 0);

        return kt;
}

void
zk_thread_exit(void)
{
        kthread_t *kt = curthread;

        ASSERT(pthread_equal(kt->t_tid, pthread_self()));

        umem_free(kt, sizeof(kthread_t));

        pthread_mutex_lock(&kthread_lock);
        kthread_nr--;
        pthread_mutex_unlock(&kthread_lock);

        pthread_cond_broadcast(&kthread_cond);
        pthread_exit((void *)TS_MAGIC);
}

void
zk_thread_join(kt_did_t tid)
{
        void *ret;

        pthread_join((pthread_t)tid, &ret);
        VERIFY3P(ret, ==, (void *)TS_MAGIC);
}

/*
 * =========================================================================
 * kstats
 * =========================================================================
 */
/*ARGSUSED*/
kstat_t *
kstat_create(char *module, int instance, char *name, char *class,
    uchar_t type, ulong_t ndata, uchar_t ks_flag)
{
        return (NULL);
}

/*ARGSUSED*/
void
kstat_install(kstat_t *ksp)
{}

/*ARGSUSED*/
void
kstat_delete(kstat_t *ksp)
{}

/*
 * =========================================================================
 * mutexes
 * =========================================================================
 */

void
mutex_init(kmutex_t *mp, char *name, int type, void *cookie)
{
        ASSERT3S(type, ==, MUTEX_DEFAULT);
        ASSERT3P(cookie, ==, NULL);
        mp->m_owner = MTX_INIT;
        mp->m_magic = MTX_MAGIC;
        VERIFY3S(pthread_mutex_init(&mp->m_lock, NULL), ==, 0);
}

void
mutex_destroy(kmutex_t *mp)
{
        ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
        ASSERT3P(mp->m_owner, ==, MTX_INIT);
        VERIFY3S(pthread_mutex_destroy(&(mp)->m_lock), ==, 0);
        mp->m_owner = MTX_DEST;
        mp->m_magic = 0;
}

void
mutex_enter(kmutex_t *mp)
{
        ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
        ASSERT3P(mp->m_owner, !=, MTX_DEST);
        ASSERT3P(mp->m_owner, !=, curthread);
        VERIFY3S(pthread_mutex_lock(&mp->m_lock), ==, 0);
        ASSERT3P(mp->m_owner, ==, MTX_INIT);
        mp->m_owner = curthread;
}

int
mutex_tryenter(kmutex_t *mp)
{
        ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
        ASSERT3P(mp->m_owner, !=, MTX_DEST);
        if (0 == pthread_mutex_trylock(&mp->m_lock)) {
                ASSERT3P(mp->m_owner, ==, MTX_INIT);
                mp->m_owner = curthread;
                return (1);
        } else {
                return (0);
        }
}

void
mutex_exit(kmutex_t *mp)
{
        ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
        ASSERT3P(mutex_owner(mp), ==, curthread);
        mp->m_owner = MTX_INIT;
        VERIFY3S(pthread_mutex_unlock(&mp->m_lock), ==, 0);
}

void *
mutex_owner(kmutex_t *mp)
{
        ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
        return (mp->m_owner);
}

int
mutex_held(kmutex_t *mp)
{
        return (mp->m_owner == curthread);
}

/*
 * =========================================================================
 * rwlocks
 * =========================================================================
 */

void
rw_init(krwlock_t *rwlp, char *name, int type, void *arg)
{
        ASSERT3S(type, ==, RW_DEFAULT);
        ASSERT3P(arg, ==, NULL);
        VERIFY3S(pthread_rwlock_init(&rwlp->rw_lock, NULL), ==, 0);
        rwlp->rw_owner = RW_INIT;
        rwlp->rw_wr_owner = RW_INIT;
        rwlp->rw_readers = 0;
        rwlp->rw_magic = RW_MAGIC;
}

void
rw_destroy(krwlock_t *rwlp)
{
        ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);

        VERIFY3S(pthread_rwlock_destroy(&rwlp->rw_lock), ==, 0);
        rwlp->rw_magic = 0;
}

void
rw_enter(krwlock_t *rwlp, krw_t rw)
{
        ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);
        ASSERT3P(rwlp->rw_owner, !=, curthread);
        ASSERT3P(rwlp->rw_wr_owner, !=, curthread);

        if (rw == RW_READER) {
                VERIFY3S(pthread_rwlock_rdlock(&rwlp->rw_lock), ==, 0);
                ASSERT3P(rwlp->rw_wr_owner, ==, RW_INIT);

                atomic_inc_uint(&rwlp->rw_readers);
        } else {
                VERIFY3S(pthread_rwlock_wrlock(&rwlp->rw_lock), ==, 0);
                ASSERT3P(rwlp->rw_wr_owner, ==, RW_INIT);
                ASSERT3U(rwlp->rw_readers, ==, 0);

                rwlp->rw_wr_owner = curthread;
        }

        rwlp->rw_owner = curthread;
}

void
rw_exit(krwlock_t *rwlp)
{
        ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);
        ASSERT(RW_LOCK_HELD(rwlp));

        if (RW_READ_HELD(rwlp))
                atomic_dec_uint(&rwlp->rw_readers);
        else
                rwlp->rw_wr_owner = RW_INIT;

        rwlp->rw_owner = RW_INIT;
        VERIFY3S(pthread_rwlock_unlock(&rwlp->rw_lock), ==, 0);
}

int
rw_tryenter(krwlock_t *rwlp, krw_t rw)
{
        int rv;

        ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);

        if (rw == RW_READER)
                rv = pthread_rwlock_tryrdlock(&rwlp->rw_lock);
        else
                rv = pthread_rwlock_trywrlock(&rwlp->rw_lock);

        if (rv == 0) {
                ASSERT3P(rwlp->rw_wr_owner, ==, RW_INIT);

                if (rw == RW_READER)
                        atomic_inc_uint(&rwlp->rw_readers);
                else {
                        ASSERT3U(rwlp->rw_readers, ==, 0);
                        rwlp->rw_wr_owner = curthread;
                }

                rwlp->rw_owner = curthread;
                return (1);
        }

        VERIFY3S(rv, ==, EBUSY);

        return (0);
}

int
rw_tryupgrade(krwlock_t *rwlp)
{
        ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);

        return (0);
}

/*
 * =========================================================================
 * condition variables
 * =========================================================================
 */

void
cv_init(kcondvar_t *cv, char *name, int type, void *arg)
{
        ASSERT3S(type, ==, CV_DEFAULT);
        cv->cv_magic = CV_MAGIC;
        VERIFY3S(pthread_cond_init(&cv->cv, NULL), ==, 0);
}

void
cv_destroy(kcondvar_t *cv)
{
        ASSERT3U(cv->cv_magic, ==, CV_MAGIC);
        VERIFY3S(pthread_cond_destroy(&cv->cv), ==, 0);
        cv->cv_magic = 0;
}

void
cv_wait(kcondvar_t *cv, kmutex_t *mp)
{
        ASSERT3U(cv->cv_magic, ==, CV_MAGIC);
        ASSERT3P(mutex_owner(mp), ==, curthread);
        mp->m_owner = MTX_INIT;
        int ret = pthread_cond_wait(&cv->cv, &mp->m_lock);
        if (ret != 0)
                VERIFY3S(ret, ==, EINTR);
        mp->m_owner = curthread;
}

clock_t
cv_timedwait(kcondvar_t *cv, kmutex_t *mp, clock_t abstime)
{
        int error;
        struct timeval tv;
        timestruc_t ts;
        clock_t delta;

        ASSERT3U(cv->cv_magic, ==, CV_MAGIC);

top:
        delta = abstime - ddi_get_lbolt();
        if (delta <= 0)
                return (-1);

        VERIFY(gettimeofday(&tv, NULL) == 0);

        ts.tv_sec = tv.tv_sec + delta / hz;
        ts.tv_nsec = tv.tv_usec * 1000 + (delta % hz) * (NANOSEC / hz);
        if (ts.tv_nsec >= NANOSEC) {
                ts.tv_sec++;
                ts.tv_nsec -= NANOSEC;
        }

        ASSERT3P(mutex_owner(mp), ==, curthread);
        mp->m_owner = MTX_INIT;
        error = pthread_cond_timedwait(&cv->cv, &mp->m_lock, &ts);
        mp->m_owner = curthread;

        if (error == ETIMEDOUT)
                return (-1);

        if (error == EINTR)
                goto top;

        VERIFY3S(error, ==, 0);

        return (1);
}

void
cv_signal(kcondvar_t *cv)
{
        ASSERT3U(cv->cv_magic, ==, CV_MAGIC);
        VERIFY3S(pthread_cond_signal(&cv->cv), ==, 0);
}

void
cv_broadcast(kcondvar_t *cv)
{
        ASSERT3U(cv->cv_magic, ==, CV_MAGIC);
        VERIFY3S(pthread_cond_broadcast(&cv->cv), ==, 0);
}

/*
 * =========================================================================
 * vnode operations
 * =========================================================================
 */
/*
 * Note: for the xxxat() versions of these functions, we assume that the
 * starting vp is always rootdir (which is true for spa_directory.c, the only
 * ZFS consumer of these interfaces).  We assert this is true, and then emulate
 * them by adding '/' in front of the path.
 */

/*ARGSUSED*/
int
vn_open(char *path, int x1, int flags, int mode, vnode_t **vpp, int x2, int x3)
{
        int fd;
        vnode_t *vp;
        int old_umask;
        char *realpath;
        struct stat64 st;
        int err;

        realpath = umem_alloc(MAXPATHLEN, UMEM_NOFAIL);

        /*
         * If we're accessing a real disk from userland, we need to use
         * the character interface to avoid caching.  This is particularly
         * important if we're trying to look at a real in-kernel storage
         * pool from userland, e.g. via zdb, because otherwise we won't
         * see the changes occurring under the segmap cache.
         * On the other hand, the stupid character device returns zero
         * for its size.  So -- gag -- we open the block device to get
         * its size, and remember it for subsequent VOP_GETATTR().
         */
#if defined(__sun__) || defined(__sun)
        if (strncmp(path, "/dev/", 5) == 0) {
#else
        if (0) {
#endif
                char *dsk;
                fd = open64(path, O_RDONLY);
                if (fd == -1) {
                        err = errno;
                        free(realpath);
                        return (err);
                }
                if (fstat64(fd, &st) == -1) {
                        err = errno;
                        close(fd);
                        free(realpath);
                        return (err);
                }
                close(fd);
                (void) sprintf(realpath, "%s", path);
                dsk = strstr(path, "/dsk/");
                if (dsk != NULL)
                        (void) sprintf(realpath + (dsk - path) + 1, "r%s",
                            dsk + 1);
        } else {
                (void) sprintf(realpath, "%s", path);
                if (!(flags & FCREAT) && stat64(realpath, &st) == -1) {
                        err = errno;
                        free(realpath);
                        return (err);
                }
        }

        if (!(flags & FCREAT) && S_ISBLK(st.st_mode)) {
#ifdef __linux__
                flags |= O_DIRECT;
#endif
                /* We shouldn't be writing to block devices in userspace */
                VERIFY(!(flags & FWRITE));
        }

        if (flags & FCREAT)
                old_umask = umask(0);

        /*
         * The construct 'flags - FREAD' conveniently maps combinations of
         * FREAD and FWRITE to the corresponding O_RDONLY, O_WRONLY, and O_RDWR.
         */
        fd = open64(realpath, flags - FREAD, mode);
        free(realpath);

        if (flags & FCREAT)
                (void) umask(old_umask);

        if (fd == -1)
                return (errno);

        if (fstat64_blk(fd, &st) == -1) {
                err = errno;
                close(fd);
                return (err);
        }

        (void) fcntl(fd, F_SETFD, FD_CLOEXEC);

        *vpp = vp = umem_zalloc(sizeof (vnode_t), UMEM_NOFAIL);

        vp->v_fd = fd;
        vp->v_size = st.st_size;
        vp->v_path = spa_strdup(path);

        return (0);
}

/*ARGSUSED*/
int
vn_openat(char *path, int x1, int flags, int mode, vnode_t **vpp, int x2,
    int x3, vnode_t *startvp, int fd)
{
        char *realpath = umem_alloc(strlen(path) + 2, UMEM_NOFAIL);
        int ret;

        ASSERT(startvp == rootdir);
        (void) sprintf(realpath, "/%s", path);

        /* fd ignored for now, need if want to simulate nbmand support */
        ret = vn_open(realpath, x1, flags, mode, vpp, x2, x3);

        umem_free(realpath, strlen(path) + 2);

        return (ret);
}

/*ARGSUSED*/
int
vn_rdwr(int uio, vnode_t *vp, void *addr, ssize_t len, offset_t offset,
        int x1, int x2, rlim64_t x3, void *x4, ssize_t *residp)
{
        ssize_t rc, done = 0, split;

        if (uio == UIO_READ) {
                rc = pread64(vp->v_fd, addr, len, offset);
        } else {
                /*
                 * To simulate partial disk writes, we split writes into two
                 * system calls so that the process can be killed in between.
                 */
                split = (len > 0 ? rand() % len : 0);
                rc = pwrite64(vp->v_fd, addr, split, offset);
                if (rc != -1) {
                        done = rc;
                        rc = pwrite64(vp->v_fd, (char *)addr + split,
                            len - split, offset + split);
                }
        }

#ifdef __linux__
        if (rc == -1 && errno == EINVAL) {
                /*
                 * Under Linux, this most likely means an alignment issue
                 * (memory or disk) due to O_DIRECT, so we abort() in order to
                 * catch the offender.
                 */
                 abort();
        }
#endif
        if (rc == -1)
                return (errno);

        done += rc;

        if (residp)
                *residp = len - done;
        else if (done != len)
                return (EIO);
        return (0);
}

void
vn_close(vnode_t *vp)
{
        close(vp->v_fd);
        spa_strfree(vp->v_path);
        umem_free(vp, sizeof (vnode_t));
}

/*
 * At a minimum we need to update the size since vdev_reopen()
 * will no longer call vn_openat().
 */
int
fop_getattr(vnode_t *vp, vattr_t *vap)
{
        struct stat64 st;
        int err;

        if (fstat64_blk(vp->v_fd, &st) == -1) {
                err = errno;
                close(vp->v_fd);
                return (err);
        }

        vap->va_size = st.st_size;
        return (0);
}

#ifdef ZFS_DEBUG

/*
 * =========================================================================
 * Figure out which debugging statements to print
 * =========================================================================
 */

static char *dprintf_string;
static int dprintf_print_all;

int
dprintf_find_string(const char *string)
{
        char *tmp_str = dprintf_string;
        int len = strlen(string);

        /*
         * Find out if this is a string we want to print.
         * String format: file1.c,function_name1,file2.c,file3.c
         */

        while (tmp_str != NULL) {
                if (strncmp(tmp_str, string, len) == 0 &&
                    (tmp_str[len] == ',' || tmp_str[len] == '\0'))
                        return (1);
                tmp_str = strchr(tmp_str, ',');
                if (tmp_str != NULL)
                        tmp_str++; /* Get rid of , */
        }
        return (0);
}

void
dprintf_setup(int *argc, char **argv)
{
        int i, j;

        /*
         * Debugging can be specified two ways: by setting the
         * environment variable ZFS_DEBUG, or by including a
         * "debug=..."  argument on the command line.  The command
         * line setting overrides the environment variable.
         */

        for (i = 1; i < *argc; i++) {
                int len = strlen("debug=");
                /* First look for a command line argument */
                if (strncmp("debug=", argv[i], len) == 0) {
                        dprintf_string = argv[i] + len;
                        /* Remove from args */
                        for (j = i; j < *argc; j++)
                                argv[j] = argv[j+1];
                        argv[j] = NULL;
                        (*argc)--;
                }
        }

        if (dprintf_string == NULL) {
                /* Look for ZFS_DEBUG environment variable */
                dprintf_string = getenv("ZFS_DEBUG");
        }

        /*
         * Are we just turning on all debugging?
         */
        if (dprintf_find_string("on"))
                dprintf_print_all = 1;
}

/*
 * =========================================================================
 * debug printfs
 * =========================================================================
 */
void
__dprintf(const char *file, const char *func, int line, const char *fmt, ...)
{
        const char *newfile;
        va_list adx;

        /*
         * Get rid of annoying "../common/" prefix to filename.
         */
        newfile = strrchr(file, '/');
        if (newfile != NULL) {
                newfile = newfile + 1; /* Get rid of leading / */
        } else {
                newfile = file;
        }

        if (dprintf_print_all ||
            dprintf_find_string(newfile) ||
            dprintf_find_string(func)) {
                /* Print out just the function name if requested */
                flockfile(stdout);
                if (dprintf_find_string("pid"))
                        (void) printf("%d ", getpid());
                if (dprintf_find_string("tid"))
                        (void) printf("%u ", (uint_t) pthread_self());
                if (dprintf_find_string("cpu"))
                        (void) printf("%u ", getcpuid());
                if (dprintf_find_string("time"))
                        (void) printf("%llu ", gethrtime());
                if (dprintf_find_string("long"))
                        (void) printf("%s, line %d: ", newfile, line);
                (void) printf("%s: ", func);
                va_start(adx, fmt);
                (void) vprintf(fmt, adx);
                va_end(adx);
                funlockfile(stdout);
        }
}

#endif /* ZFS_DEBUG */

/*
 * =========================================================================
 * cmn_err() and panic()
 * =========================================================================
 */
static char ce_prefix[CE_IGNORE][10] = { "", "NOTICE: ", "WARNING: ", "" };
static char ce_suffix[CE_IGNORE][2] = { "", "\n", "\n", "" };

void
vpanic(const char *fmt, va_list adx)
{
        (void) fprintf(stderr, "error: ");
        (void) vfprintf(stderr, fmt, adx);
        (void) fprintf(stderr, "\n");

        abort();        /* think of it as a "user-level crash dump" */
}

void
panic(const char *fmt, ...)
{
        va_list adx;

        va_start(adx, fmt);
        vpanic(fmt, adx);
        va_end(adx);
}

void
vcmn_err(int ce, const char *fmt, va_list adx)
{
        if (ce == CE_PANIC)
                vpanic(fmt, adx);
        if (ce != CE_NOTE) {    /* suppress noise in userland stress testing */
                (void) fprintf(stderr, "%s", ce_prefix[ce]);
                (void) vfprintf(stderr, fmt, adx);
                (void) fprintf(stderr, "%s", ce_suffix[ce]);
        }
}

/*PRINTFLIKE2*/
void
cmn_err(int ce, const char *fmt, ...)
{
        va_list adx;

        va_start(adx, fmt);
        vcmn_err(ce, fmt, adx);
        va_end(adx);
}

/*
 * =========================================================================
 * kobj interfaces
 * =========================================================================
 */
struct _buf *
kobj_open_file(char *name)
{
        struct _buf *file;
        vnode_t *vp;

        /* set vp as the _fd field of the file */
        if (vn_openat(name, UIO_SYSSPACE, FREAD, 0, &vp, 0, 0, rootdir,
            -1) != 0)
                return ((void *)-1UL);

        file = umem_zalloc(sizeof (struct _buf), UMEM_NOFAIL);
        file->_fd = (intptr_t)vp;
        return (file);
}

int
kobj_read_file(struct _buf *file, char *buf, unsigned size, unsigned off)
{
        ssize_t resid;

        vn_rdwr(UIO_READ, (vnode_t *)file->_fd, buf, size, (offset_t)off,
            UIO_SYSSPACE, 0, 0, 0, &resid);

        return (size - resid);
}

void
kobj_close_file(struct _buf *file)
{
        vn_close((vnode_t *)file->_fd);
        umem_free(file, sizeof (struct _buf));
}

int
kobj_get_filesize(struct _buf *file, uint64_t *size)
{
        struct stat64 st;
        vnode_t *vp = (vnode_t *)file->_fd;

        if (fstat64(vp->v_fd, &st) == -1) {
                vn_close(vp);
                return (errno);
        }
        *size = st.st_size;
        return (0);
}

/*
 * =========================================================================
 * misc routines
 * =========================================================================
 */

void
delay(clock_t ticks)
{
        poll(0, 0, ticks * (1000 / hz));
}

/*
 * Find highest one bit set.
 *      Returns bit number + 1 of highest bit that is set, otherwise returns 0.
 * High order bit is 31 (or 63 in _LP64 kernel).
 */
int
highbit(ulong_t i)
{
        register int h = 1;

        if (i == 0)
                return (0);
#ifdef _LP64
        if (i & 0xffffffff00000000ul) {
                h += 32; i >>= 32;
        }
#endif
        if (i & 0xffff0000) {
                h += 16; i >>= 16;
        }
        if (i & 0xff00) {
                h += 8; i >>= 8;
        }
        if (i & 0xf0) {
                h += 4; i >>= 4;
        }
        if (i & 0xc) {
                h += 2; i >>= 2;
        }
        if (i & 0x2) {
                h += 1;
        }
        return (h);
}

static int random_fd = -1, urandom_fd = -1;

static int
random_get_bytes_common(uint8_t *ptr, size_t len, int fd)
{
        size_t resid = len;
        ssize_t bytes;

        ASSERT(fd != -1);

        while (resid != 0) {
                bytes = read(fd, ptr, resid);
                ASSERT3S(bytes, >=, 0);
                ptr += bytes;
                resid -= bytes;
        }

        return (0);
}

int
random_get_bytes(uint8_t *ptr, size_t len)
{
        return (random_get_bytes_common(ptr, len, random_fd));
}

int
random_get_pseudo_bytes(uint8_t *ptr, size_t len)
{
        return (random_get_bytes_common(ptr, len, urandom_fd));
}

int
ddi_strtoul(const char *hw_serial, char **nptr, int base, unsigned long *result)
{
        char *end;

        *result = strtoul(hw_serial, &end, base);
        if (*result == 0)
                return (errno);
        return (0);
}

int
ddi_strtoull(const char *str, char **nptr, int base, u_longlong_t *result)
{
        char *end;

        *result = strtoull(str, &end, base);
        if (*result == 0)
                return (errno);
        return (0);
}

/*
 * =========================================================================
 * kernel emulation setup & teardown
 * =========================================================================
 */
static int
umem_out_of_memory(void)
{
        char errmsg[] = "out of memory -- generating core dump\n";

        (void) fprintf(stderr, "%s", errmsg);
        abort();
        return (0);
}

void
kernel_init(int mode)
{
        umem_nofail_callback(umem_out_of_memory);

        physmem = sysconf(_SC_PHYS_PAGES);

        dprintf("physmem = %llu pages (%.2f GB)\n", physmem,
            (double)physmem * sysconf(_SC_PAGE_SIZE) / (1ULL << 30));

        (void) snprintf(hw_serial, sizeof (hw_serial), "%ld",
            (mode & FWRITE) ? gethostid() : 0);

        VERIFY((random_fd = open("/dev/random", O_RDONLY)) != -1);
        VERIFY((urandom_fd = open("/dev/urandom", O_RDONLY)) != -1);

        thread_init();
        system_taskq_init();

        spa_init(mode);
}

void
kernel_fini(void)
{
        spa_fini();

        system_taskq_fini();
        thread_fini();

        close(random_fd);
        close(urandom_fd);

        random_fd = -1;
        urandom_fd = -1;
}

uid_t
crgetuid(cred_t *cr)
{
        return (0);
}

gid_t
crgetgid(cred_t *cr)
{
        return (0);
}

int
crgetngroups(cred_t *cr)
{
        return (0);
}

gid_t *
crgetgroups(cred_t *cr)
{
        return (NULL);
}

int
zfs_secpolicy_snapshot_perms(const char *name, cred_t *cr)
{
        return (0);
}

int
zfs_secpolicy_rename_perms(const char *from, const char *to, cred_t *cr)
{
        return (0);
}

int
zfs_secpolicy_destroy_perms(const char *name, cred_t *cr)
{
        return (0);
}

ksiddomain_t *
ksid_lookupdomain(const char *dom)
{
        ksiddomain_t *kd;

        kd = umem_zalloc(sizeof (ksiddomain_t), UMEM_NOFAIL);
        kd->kd_name = spa_strdup(dom);
        return (kd);
}

void
ksiddomain_rele(ksiddomain_t *ksid)
{
        spa_strfree(ksid->kd_name);
        umem_free(ksid, sizeof (ksiddomain_t));
}

char *
kmem_vasprintf(const char *fmt, va_list adx)
{
        char *buf = NULL;
        va_list adx_copy;

        va_copy(adx_copy, adx);
        VERIFY(vasprintf(&buf, fmt, adx_copy) != -1);
        va_end(adx_copy);

        return (buf);
}

char *
kmem_asprintf(const char *fmt, ...)
{
        char *buf = NULL;
        va_list adx;

        va_start(adx, fmt);
        VERIFY(vasprintf(&buf, fmt, adx) != -1);
        va_end(adx);

        return (buf);
}

/* ARGSUSED */
int
zfs_onexit_fd_hold(int fd, minor_t *minorp)
{
        *minorp = 0;
        return (0);
}

/* ARGSUSED */
void
zfs_onexit_fd_rele(int fd)
{
}

/* ARGSUSED */
int
zfs_onexit_add_cb(minor_t minor, void (*func)(void *), void *data,
    uint64_t *action_handle)
{
        return (0);
}

/* ARGSUSED */
int
zfs_onexit_del_cb(minor_t minor, uint64_t action_handle, boolean_t fire)
{
        return (0);
}

/* ARGSUSED */
int
zfs_onexit_cb_data(minor_t minor, uint64_t action_handle, void **data)
{
        return (0);
}