4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
32 #include <sys/signal.h>
35 #include <sys/processor.h>
36 #include <sys/zfs_context.h>
37 #include <sys/utsname.h>
38 #include <sys/systeminfo.h>
41 * Emulation of kernel services in userland.
46 vnode_t *rootdir = (vnode_t *)0xabcd1234;
47 char hw_serial[HW_HOSTID_LEN];
49 struct utsname utsname = {
50 "userland", "libzpool", "1", "1", "na"
53 /* this only exists to have its address taken */
57 * =========================================================================
59 * =========================================================================
62 pthread_cond_t kthread_cond = PTHREAD_COND_INITIALIZER;
63 pthread_mutex_t kthread_lock = PTHREAD_MUTEX_INITIALIZER;
64 pthread_key_t kthread_key;
72 VERIFY3S(pthread_key_create(&kthread_key, NULL), ==, 0);
74 /* Create entry for primary kthread */
75 kt = umem_zalloc(sizeof(kthread_t), UMEM_NOFAIL);
76 kt->t_tid = pthread_self();
79 VERIFY3S(pthread_setspecific(kthread_key, kt), ==, 0);
81 /* Only the main thread should be running at the moment */
82 ASSERT3S(kthread_nr, ==, 0);
89 kthread_t *kt = curthread;
91 ASSERT(pthread_equal(kt->t_tid, pthread_self()));
92 ASSERT3P(kt->t_func, ==, NULL);
94 umem_free(kt, sizeof(kthread_t));
96 /* Wait for all threads to exit via thread_exit() */
97 VERIFY3S(pthread_mutex_lock(&kthread_lock), ==, 0);
99 kthread_nr--; /* Main thread is exiting */
101 while (kthread_nr > 0)
102 VERIFY3S(pthread_cond_wait(&kthread_cond, &kthread_lock), ==,
105 ASSERT3S(kthread_nr, ==, 0);
106 VERIFY3S(pthread_mutex_unlock(&kthread_lock), ==, 0);
108 VERIFY3S(pthread_key_delete(kthread_key), ==, 0);
112 zk_thread_current(void)
114 kthread_t *kt = pthread_getspecific(kthread_key);
116 ASSERT3P(kt, !=, NULL);
122 zk_thread_helper(void *arg)
124 kthread_t *kt = (kthread_t *) arg;
126 VERIFY3S(pthread_setspecific(kthread_key, kt), ==, 0);
128 VERIFY3S(pthread_mutex_lock(&kthread_lock), ==, 0);
130 VERIFY3S(pthread_mutex_unlock(&kthread_lock), ==, 0);
132 kt->t_tid = pthread_self();
133 ((thread_func_arg_t) kt->t_func)(kt->t_arg);
135 /* Unreachable, thread must exit with thread_exit() */
142 zk_thread_create(caddr_t stk, size_t stksize, thread_func_t func, void *arg,
143 size_t len, proc_t *pp, int state, pri_t pri)
149 ASSERT3S(state & ~TS_RUN, ==, 0);
151 kt = umem_zalloc(sizeof(kthread_t), UMEM_NOFAIL);
156 * The Solaris kernel stack size is 24k for x86/x86_64.
157 * The Linux kernel stack size is 8k for x86/x86_64.
159 * We reduce the default stack size in userspace, to ensure
160 * we observe stack overruns in user space as well as in
161 * kernel space. PTHREAD_STACK_MIN is the minimum stack
162 * required for a NULL procedure in user space and is added
163 * in to the stack requirements.
165 * Some buggy NPTL threading implementations include the
166 * guard area within the stack size allocations. In
167 * this case we allocate an extra page to account for the
168 * guard area since we only have two pages of usable stack
172 stack = PTHREAD_STACK_MIN + MAX(stksize, STACK_SIZE) +
175 VERIFY3S(pthread_attr_init(&attr), ==, 0);
176 VERIFY3S(pthread_attr_setstacksize(&attr, stack), ==, 0);
177 VERIFY3S(pthread_attr_setguardsize(&attr, PAGESIZE), ==, 0);
179 VERIFY3S(pthread_create(&kt->t_tid, &attr, &zk_thread_helper, kt),
182 VERIFY3S(pthread_attr_destroy(&attr), ==, 0);
190 kthread_t *kt = curthread;
192 ASSERT(pthread_equal(kt->t_tid, pthread_self()));
194 umem_free(kt, sizeof(kthread_t));
196 pthread_mutex_lock(&kthread_lock);
198 pthread_mutex_unlock(&kthread_lock);
200 pthread_cond_broadcast(&kthread_cond);
201 pthread_exit((void *)TS_MAGIC);
205 zk_thread_join(kt_did_t tid)
209 pthread_join((pthread_t)tid, &ret);
210 VERIFY3P(ret, ==, (void *)TS_MAGIC);
214 * =========================================================================
216 * =========================================================================
220 kstat_create(char *module, int instance, char *name, char *class,
221 uchar_t type, ulong_t ndata, uchar_t ks_flag)
228 kstat_install(kstat_t *ksp)
233 kstat_delete(kstat_t *ksp)
237 * =========================================================================
239 * =========================================================================
243 mutex_init(kmutex_t *mp, char *name, int type, void *cookie)
245 ASSERT3S(type, ==, MUTEX_DEFAULT);
246 ASSERT3P(cookie, ==, NULL);
247 mp->m_owner = MTX_INIT;
248 mp->m_magic = MTX_MAGIC;
249 VERIFY3S(pthread_mutex_init(&mp->m_lock, NULL), ==, 0);
253 mutex_destroy(kmutex_t *mp)
255 ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
256 ASSERT3P(mp->m_owner, ==, MTX_INIT);
257 VERIFY3S(pthread_mutex_destroy(&(mp)->m_lock), ==, 0);
258 mp->m_owner = MTX_DEST;
263 mutex_enter(kmutex_t *mp)
265 ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
266 ASSERT3P(mp->m_owner, !=, MTX_DEST);
267 ASSERT3P(mp->m_owner, !=, curthread);
268 VERIFY3S(pthread_mutex_lock(&mp->m_lock), ==, 0);
269 ASSERT3P(mp->m_owner, ==, MTX_INIT);
270 mp->m_owner = curthread;
274 mutex_tryenter(kmutex_t *mp)
276 ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
277 ASSERT3P(mp->m_owner, !=, MTX_DEST);
278 if (0 == pthread_mutex_trylock(&mp->m_lock)) {
279 ASSERT3P(mp->m_owner, ==, MTX_INIT);
280 mp->m_owner = curthread;
288 mutex_exit(kmutex_t *mp)
290 ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
291 ASSERT3P(mutex_owner(mp), ==, curthread);
292 mp->m_owner = MTX_INIT;
293 VERIFY3S(pthread_mutex_unlock(&mp->m_lock), ==, 0);
297 mutex_owner(kmutex_t *mp)
299 ASSERT3U(mp->m_magic, ==, MTX_MAGIC);
300 return (mp->m_owner);
304 mutex_held(kmutex_t *mp)
306 return (mp->m_owner == curthread);
310 * =========================================================================
312 * =========================================================================
316 rw_init(krwlock_t *rwlp, char *name, int type, void *arg)
318 ASSERT3S(type, ==, RW_DEFAULT);
319 ASSERT3P(arg, ==, NULL);
320 VERIFY3S(pthread_rwlock_init(&rwlp->rw_lock, NULL), ==, 0);
321 rwlp->rw_owner = RW_INIT;
322 rwlp->rw_wr_owner = RW_INIT;
323 rwlp->rw_readers = 0;
324 rwlp->rw_magic = RW_MAGIC;
328 rw_destroy(krwlock_t *rwlp)
330 ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);
332 VERIFY3S(pthread_rwlock_destroy(&rwlp->rw_lock), ==, 0);
337 rw_enter(krwlock_t *rwlp, krw_t rw)
339 ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);
340 ASSERT3P(rwlp->rw_owner, !=, curthread);
341 ASSERT3P(rwlp->rw_wr_owner, !=, curthread);
343 if (rw == RW_READER) {
344 VERIFY3S(pthread_rwlock_rdlock(&rwlp->rw_lock), ==, 0);
345 ASSERT3P(rwlp->rw_wr_owner, ==, RW_INIT);
347 atomic_inc_uint(&rwlp->rw_readers);
349 VERIFY3S(pthread_rwlock_wrlock(&rwlp->rw_lock), ==, 0);
350 ASSERT3P(rwlp->rw_wr_owner, ==, RW_INIT);
351 ASSERT3U(rwlp->rw_readers, ==, 0);
353 rwlp->rw_wr_owner = curthread;
356 rwlp->rw_owner = curthread;
360 rw_exit(krwlock_t *rwlp)
362 ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);
363 ASSERT(RW_LOCK_HELD(rwlp));
365 if (RW_READ_HELD(rwlp))
366 atomic_dec_uint(&rwlp->rw_readers);
368 rwlp->rw_wr_owner = RW_INIT;
370 rwlp->rw_owner = RW_INIT;
371 VERIFY3S(pthread_rwlock_unlock(&rwlp->rw_lock), ==, 0);
375 rw_tryenter(krwlock_t *rwlp, krw_t rw)
379 ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);
382 rv = pthread_rwlock_tryrdlock(&rwlp->rw_lock);
384 rv = pthread_rwlock_trywrlock(&rwlp->rw_lock);
387 ASSERT3P(rwlp->rw_wr_owner, ==, RW_INIT);
390 atomic_inc_uint(&rwlp->rw_readers);
392 ASSERT3U(rwlp->rw_readers, ==, 0);
393 rwlp->rw_wr_owner = curthread;
396 rwlp->rw_owner = curthread;
400 VERIFY3S(rv, ==, EBUSY);
406 rw_tryupgrade(krwlock_t *rwlp)
408 ASSERT3U(rwlp->rw_magic, ==, RW_MAGIC);
414 * =========================================================================
415 * condition variables
416 * =========================================================================
420 cv_init(kcondvar_t *cv, char *name, int type, void *arg)
422 ASSERT3S(type, ==, CV_DEFAULT);
423 cv->cv_magic = CV_MAGIC;
424 VERIFY3S(pthread_cond_init(&cv->cv, NULL), ==, 0);
428 cv_destroy(kcondvar_t *cv)
430 ASSERT3U(cv->cv_magic, ==, CV_MAGIC);
431 VERIFY3S(pthread_cond_destroy(&cv->cv), ==, 0);
436 cv_wait(kcondvar_t *cv, kmutex_t *mp)
438 ASSERT3U(cv->cv_magic, ==, CV_MAGIC);
439 ASSERT3P(mutex_owner(mp), ==, curthread);
440 mp->m_owner = MTX_INIT;
441 int ret = pthread_cond_wait(&cv->cv, &mp->m_lock);
443 VERIFY3S(ret, ==, EINTR);
444 mp->m_owner = curthread;
448 cv_timedwait(kcondvar_t *cv, kmutex_t *mp, clock_t abstime)
455 ASSERT3U(cv->cv_magic, ==, CV_MAGIC);
458 delta = abstime - ddi_get_lbolt();
462 VERIFY(gettimeofday(&tv, NULL) == 0);
464 ts.tv_sec = tv.tv_sec + delta / hz;
465 ts.tv_nsec = tv.tv_usec * 1000 + (delta % hz) * (NANOSEC / hz);
466 if (ts.tv_nsec >= NANOSEC) {
468 ts.tv_nsec -= NANOSEC;
471 ASSERT3P(mutex_owner(mp), ==, curthread);
472 mp->m_owner = MTX_INIT;
473 error = pthread_cond_timedwait(&cv->cv, &mp->m_lock, &ts);
474 mp->m_owner = curthread;
476 if (error == ETIMEDOUT)
482 VERIFY3S(error, ==, 0);
488 cv_signal(kcondvar_t *cv)
490 ASSERT3U(cv->cv_magic, ==, CV_MAGIC);
491 VERIFY3S(pthread_cond_signal(&cv->cv), ==, 0);
495 cv_broadcast(kcondvar_t *cv)
497 ASSERT3U(cv->cv_magic, ==, CV_MAGIC);
498 VERIFY3S(pthread_cond_broadcast(&cv->cv), ==, 0);
502 * =========================================================================
504 * =========================================================================
507 * Note: for the xxxat() versions of these functions, we assume that the
508 * starting vp is always rootdir (which is true for spa_directory.c, the only
509 * ZFS consumer of these interfaces). We assert this is true, and then emulate
510 * them by adding '/' in front of the path.
515 vn_open(char *path, int x1, int flags, int mode, vnode_t **vpp, int x2, int x3)
524 realpath = umem_alloc(MAXPATHLEN, UMEM_NOFAIL);
527 * If we're accessing a real disk from userland, we need to use
528 * the character interface to avoid caching. This is particularly
529 * important if we're trying to look at a real in-kernel storage
530 * pool from userland, e.g. via zdb, because otherwise we won't
531 * see the changes occurring under the segmap cache.
532 * On the other hand, the stupid character device returns zero
533 * for its size. So -- gag -- we open the block device to get
534 * its size, and remember it for subsequent VOP_GETATTR().
536 if (strncmp(path, "/dev/", 5) == 0) {
538 fd = open64(path, O_RDONLY);
544 if (fstat64(fd, &st) == -1) {
551 (void) sprintf(realpath, "%s", path);
552 dsk = strstr(path, "/dsk/");
554 (void) sprintf(realpath + (dsk - path) + 1, "r%s",
557 (void) sprintf(realpath, "%s", path);
558 if (!(flags & FCREAT) && stat64(realpath, &st) == -1) {
566 old_umask = umask(0);
569 * The construct 'flags - FREAD' conveniently maps combinations of
570 * FREAD and FWRITE to the corresponding O_RDONLY, O_WRONLY, and O_RDWR.
572 fd = open64(realpath, flags - FREAD, mode);
576 (void) umask(old_umask);
581 if (fstat64(fd, &st) == -1) {
587 (void) fcntl(fd, F_SETFD, FD_CLOEXEC);
589 *vpp = vp = umem_zalloc(sizeof (vnode_t), UMEM_NOFAIL);
592 vp->v_size = st.st_size;
593 vp->v_path = spa_strdup(path);
600 vn_openat(char *path, int x1, int flags, int mode, vnode_t **vpp, int x2,
601 int x3, vnode_t *startvp, int fd)
603 char *realpath = umem_alloc(strlen(path) + 2, UMEM_NOFAIL);
606 ASSERT(startvp == rootdir);
607 (void) sprintf(realpath, "/%s", path);
609 /* fd ignored for now, need if want to simulate nbmand support */
610 ret = vn_open(realpath, x1, flags, mode, vpp, x2, x3);
612 umem_free(realpath, strlen(path) + 2);
619 vn_rdwr(int uio, vnode_t *vp, void *addr, ssize_t len, offset_t offset,
620 int x1, int x2, rlim64_t x3, void *x4, ssize_t *residp)
622 ssize_t rc, done = 0, split;
624 if (uio == UIO_READ) {
625 rc = pread64(vp->v_fd, addr, len, offset);
628 * To simulate partial disk writes, we split writes into two
629 * system calls so that the process can be killed in between.
631 split = (len > 0 ? rand() % len : 0);
632 rc = pwrite64(vp->v_fd, addr, split, offset);
635 rc = pwrite64(vp->v_fd, (char *)addr + split,
636 len - split, offset + split);
646 *residp = len - done;
647 else if (done != len)
653 vn_close(vnode_t *vp)
656 spa_strfree(vp->v_path);
657 umem_free(vp, sizeof (vnode_t));
661 * At a minimum we need to update the size since vdev_reopen()
662 * will no longer call vn_openat().
665 fop_getattr(vnode_t *vp, vattr_t *vap)
669 if (fstat64(vp->v_fd, &st) == -1) {
674 vap->va_size = st.st_size;
681 * =========================================================================
682 * Figure out which debugging statements to print
683 * =========================================================================
686 static char *dprintf_string;
687 static int dprintf_print_all;
690 dprintf_find_string(const char *string)
692 char *tmp_str = dprintf_string;
693 int len = strlen(string);
696 * Find out if this is a string we want to print.
697 * String format: file1.c,function_name1,file2.c,file3.c
700 while (tmp_str != NULL) {
701 if (strncmp(tmp_str, string, len) == 0 &&
702 (tmp_str[len] == ',' || tmp_str[len] == '\0'))
704 tmp_str = strchr(tmp_str, ',');
706 tmp_str++; /* Get rid of , */
712 dprintf_setup(int *argc, char **argv)
717 * Debugging can be specified two ways: by setting the
718 * environment variable ZFS_DEBUG, or by including a
719 * "debug=..." argument on the command line. The command
720 * line setting overrides the environment variable.
723 for (i = 1; i < *argc; i++) {
724 int len = strlen("debug=");
725 /* First look for a command line argument */
726 if (strncmp("debug=", argv[i], len) == 0) {
727 dprintf_string = argv[i] + len;
728 /* Remove from args */
729 for (j = i; j < *argc; j++)
736 if (dprintf_string == NULL) {
737 /* Look for ZFS_DEBUG environment variable */
738 dprintf_string = getenv("ZFS_DEBUG");
742 * Are we just turning on all debugging?
744 if (dprintf_find_string("on"))
745 dprintf_print_all = 1;
749 * =========================================================================
751 * =========================================================================
754 __dprintf(const char *file, const char *func, int line, const char *fmt, ...)
760 * Get rid of annoying "../common/" prefix to filename.
762 newfile = strrchr(file, '/');
763 if (newfile != NULL) {
764 newfile = newfile + 1; /* Get rid of leading / */
769 if (dprintf_print_all ||
770 dprintf_find_string(newfile) ||
771 dprintf_find_string(func)) {
772 /* Print out just the function name if requested */
774 if (dprintf_find_string("pid"))
775 (void) printf("%d ", getpid());
776 if (dprintf_find_string("tid"))
777 (void) printf("%u ", (uint_t) pthread_self());
778 if (dprintf_find_string("cpu"))
779 (void) printf("%u ", getcpuid());
780 if (dprintf_find_string("time"))
781 (void) printf("%llu ", gethrtime());
782 if (dprintf_find_string("long"))
783 (void) printf("%s, line %d: ", newfile, line);
784 (void) printf("%s: ", func);
786 (void) vprintf(fmt, adx);
792 #endif /* ZFS_DEBUG */
795 * =========================================================================
796 * cmn_err() and panic()
797 * =========================================================================
799 static char ce_prefix[CE_IGNORE][10] = { "", "NOTICE: ", "WARNING: ", "" };
800 static char ce_suffix[CE_IGNORE][2] = { "", "\n", "\n", "" };
803 vpanic(const char *fmt, va_list adx)
805 (void) fprintf(stderr, "error: ");
806 (void) vfprintf(stderr, fmt, adx);
807 (void) fprintf(stderr, "\n");
809 abort(); /* think of it as a "user-level crash dump" */
813 panic(const char *fmt, ...)
823 vcmn_err(int ce, const char *fmt, va_list adx)
827 if (ce != CE_NOTE) { /* suppress noise in userland stress testing */
828 (void) fprintf(stderr, "%s", ce_prefix[ce]);
829 (void) vfprintf(stderr, fmt, adx);
830 (void) fprintf(stderr, "%s", ce_suffix[ce]);
836 cmn_err(int ce, const char *fmt, ...)
841 vcmn_err(ce, fmt, adx);
846 * =========================================================================
848 * =========================================================================
851 kobj_open_file(char *name)
856 /* set vp as the _fd field of the file */
857 if (vn_openat(name, UIO_SYSSPACE, FREAD, 0, &vp, 0, 0, rootdir,
859 return ((void *)-1UL);
861 file = umem_zalloc(sizeof (struct _buf), UMEM_NOFAIL);
862 file->_fd = (intptr_t)vp;
867 kobj_read_file(struct _buf *file, char *buf, unsigned size, unsigned off)
871 vn_rdwr(UIO_READ, (vnode_t *)file->_fd, buf, size, (offset_t)off,
872 UIO_SYSSPACE, 0, 0, 0, &resid);
874 return (size - resid);
878 kobj_close_file(struct _buf *file)
880 vn_close((vnode_t *)file->_fd);
881 umem_free(file, sizeof (struct _buf));
885 kobj_get_filesize(struct _buf *file, uint64_t *size)
888 vnode_t *vp = (vnode_t *)file->_fd;
890 if (fstat64(vp->v_fd, &st) == -1) {
899 * =========================================================================
901 * =========================================================================
907 poll(0, 0, ticks * (1000 / hz));
911 * Find highest one bit set.
912 * Returns bit number + 1 of highest bit that is set, otherwise returns 0.
913 * High order bit is 31 (or 63 in _LP64 kernel).
923 if (i & 0xffffffff00000000ul) {
927 if (i & 0xffff0000) {
945 static int random_fd = -1, urandom_fd = -1;
948 random_get_bytes_common(uint8_t *ptr, size_t len, int fd)
956 bytes = read(fd, ptr, resid);
957 ASSERT3S(bytes, >=, 0);
966 random_get_bytes(uint8_t *ptr, size_t len)
968 return (random_get_bytes_common(ptr, len, random_fd));
972 random_get_pseudo_bytes(uint8_t *ptr, size_t len)
974 return (random_get_bytes_common(ptr, len, urandom_fd));
978 ddi_strtoul(const char *hw_serial, char **nptr, int base, unsigned long *result)
982 *result = strtoul(hw_serial, &end, base);
989 ddi_strtoull(const char *str, char **nptr, int base, u_longlong_t *result)
993 *result = strtoull(str, &end, base);
1000 * =========================================================================
1001 * kernel emulation setup & teardown
1002 * =========================================================================
1005 umem_out_of_memory(void)
1007 char errmsg[] = "out of memory -- generating core dump\n";
1009 (void) fprintf(stderr, "%s", errmsg);
1015 kernel_init(int mode)
1017 umem_nofail_callback(umem_out_of_memory);
1019 physmem = sysconf(_SC_PHYS_PAGES);
1021 dprintf("physmem = %llu pages (%.2f GB)\n", physmem,
1022 (double)physmem * sysconf(_SC_PAGE_SIZE) / (1ULL << 30));
1024 (void) snprintf(hw_serial, sizeof (hw_serial), "%ld",
1025 (mode & FWRITE) ? gethostid() : 0);
1027 VERIFY((random_fd = open("/dev/random", O_RDONLY)) != -1);
1028 VERIFY((urandom_fd = open("/dev/urandom", O_RDONLY)) != -1);
1031 system_taskq_init();
1041 system_taskq_fini();
1052 crgetuid(cred_t *cr)
1058 crgetgid(cred_t *cr)
1064 crgetngroups(cred_t *cr)
1070 crgetgroups(cred_t *cr)
1076 zfs_secpolicy_snapshot_perms(const char *name, cred_t *cr)
1082 zfs_secpolicy_rename_perms(const char *from, const char *to, cred_t *cr)
1088 zfs_secpolicy_destroy_perms(const char *name, cred_t *cr)
1094 ksid_lookupdomain(const char *dom)
1098 kd = umem_zalloc(sizeof (ksiddomain_t), UMEM_NOFAIL);
1099 kd->kd_name = spa_strdup(dom);
1104 ksiddomain_rele(ksiddomain_t *ksid)
1106 spa_strfree(ksid->kd_name);
1107 umem_free(ksid, sizeof (ksiddomain_t));
1111 kmem_vasprintf(const char *fmt, va_list adx)
1116 va_copy(adx_copy, adx);
1117 VERIFY(vasprintf(&buf, fmt, adx_copy) != -1);
1124 kmem_asprintf(const char *fmt, ...)
1130 VERIFY(vasprintf(&buf, fmt, adx) != -1);
1138 zfs_onexit_fd_hold(int fd, minor_t *minorp)
1146 zfs_onexit_fd_rele(int fd)
1152 zfs_onexit_add_cb(minor_t minor, void (*func)(void *), void *data,
1153 uint64_t *action_handle)
1160 zfs_onexit_del_cb(minor_t minor, uint64_t action_handle, boolean_t fire)
1167 zfs_onexit_cb_data(minor_t minor, uint64_t action_handle, void **data)