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/*
* 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) 2012 by Delphix. All rights reserved.
*/
/*
* LibZFS_Core (lzc) is intended to replace most functionality in libzfs.
* It has the following characteristics:
*
* - Thread Safe. libzfs_core is accessible concurrently from multiple
* threads. This is accomplished primarily by avoiding global data
* (e.g. caching). Since it's thread-safe, there is no reason for a
* process to have multiple libzfs "instances". Therefore, we store
* our few pieces of data (e.g. the file descriptor) in global
* variables. The fd is reference-counted so that the libzfs_core
* library can be "initialized" multiple times (e.g. by different
* consumers within the same process).
*
* - Committed Interface. The libzfs_core interface will be committed,
* therefore consumers can compile against it and be confident that
* their code will continue to work on future releases of this code.
* Currently, the interface is Evolving (not Committed), but we intend
* to commit to it once it is more complete and we determine that it
* meets the needs of all consumers.
*
* - Programatic Error Handling. libzfs_core communicates errors with
* defined error numbers, and doesn't print anything to stdout/stderr.
*
* - Thin Layer. libzfs_core is a thin layer, marshaling arguments
* to/from the kernel ioctls. There is generally a 1:1 correspondence
* between libzfs_core functions and ioctls to /dev/zfs.
*
* - Clear Atomicity. Because libzfs_core functions are generally 1:1
* with kernel ioctls, and kernel ioctls are general atomic, each
* libzfs_core function is atomic. For example, creating multiple
* snapshots with a single call to lzc_snapshot() is atomic -- it
* can't fail with only some of the requested snapshots created, even
* in the event of power loss or system crash.
*
* - Continued libzfs Support. Some higher-level operations (e.g.
* support for "zfs send -R") are too complicated to fit the scope of
* libzfs_core. This functionality will continue to live in libzfs.
* Where appropriate, libzfs will use the underlying atomic operations
* of libzfs_core. For example, libzfs may implement "zfs send -R |
* zfs receive" by using individual "send one snapshot", rename,
* destroy, and "receive one snapshot" operations in libzfs_core.
* /sbin/zfs and /zbin/zpool will link with both libzfs and
* libzfs_core. Other consumers should aim to use only libzfs_core,
* since that will be the supported, stable interface going forwards.
*/
#define _IN_LIBZFS_CORE_
#include <libzfs_core.h>
#include <ctype.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <sys/nvpair.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/zfs_ioctl.h>
#include "libzfs_core_compat.h"
#include "libzfs_compat.h"
#ifdef __FreeBSD__
extern int zfs_ioctl_version;
#endif
static int g_fd;
static pthread_mutex_t g_lock = PTHREAD_MUTEX_INITIALIZER;
static int g_refcount;
int
libzfs_core_init(void)
{
(void) pthread_mutex_lock(&g_lock);
if (g_refcount == 0) {
g_fd = open("/dev/zfs", O_RDWR);
if (g_fd < 0) {
(void) pthread_mutex_unlock(&g_lock);
return (errno);
}
}
g_refcount++;
(void) pthread_mutex_unlock(&g_lock);
return (0);
}
void
libzfs_core_fini(void)
{
(void) pthread_mutex_lock(&g_lock);
ASSERT3S(g_refcount, >, 0);
g_refcount--;
if (g_refcount == 0)
(void) close(g_fd);
(void) pthread_mutex_unlock(&g_lock);
}
static int
lzc_ioctl(zfs_ioc_t ioc, const char *name,
nvlist_t *source, nvlist_t **resultp)
{
zfs_cmd_t zc = { 0 };
int error = 0;
char *packed;
#ifdef __FreeBSD__
nvlist_t *oldsource;
#endif
size_t size;
ASSERT3S(g_refcount, >, 0);
(void) strlcpy(zc.zc_name, name, sizeof (zc.zc_name));
#ifdef __FreeBSD__
if (zfs_ioctl_version == ZFS_IOCVER_UNDEF)
zfs_ioctl_version = get_zfs_ioctl_version();
if (zfs_ioctl_version < ZFS_IOCVER_LZC) {
oldsource = source;
error = lzc_compat_pre(&zc, &ioc, &source);
if (error)
return (error);
}
#endif
packed = fnvlist_pack(source, &size);
zc.zc_nvlist_src = (uint64_t)(uintptr_t)packed;
zc.zc_nvlist_src_size = size;
if (resultp != NULL) {
zc.zc_nvlist_dst_size = MAX(size * 2, 128 * 1024);
zc.zc_nvlist_dst = (uint64_t)(uintptr_t)
malloc(zc.zc_nvlist_dst_size);
#ifdef illumos
if (zc.zc_nvlist_dst == NULL) {
#else
if (zc.zc_nvlist_dst == 0) {
#endif
error = ENOMEM;
goto out;
}
}
while (ioctl(g_fd, ioc, &zc) != 0) {
if (errno == ENOMEM && resultp != NULL) {
free((void *)(uintptr_t)zc.zc_nvlist_dst);
zc.zc_nvlist_dst_size *= 2;
zc.zc_nvlist_dst = (uint64_t)(uintptr_t)
malloc(zc.zc_nvlist_dst_size);
#ifdef illumos
if (zc.zc_nvlist_dst == NULL) {
#else
if (zc.zc_nvlist_dst == 0) {
#endif
error = ENOMEM;
goto out;
}
} else {
error = errno;
break;
}
}
#ifdef __FreeBSD__
if (zfs_ioctl_version < ZFS_IOCVER_LZC)
lzc_compat_post(&zc, ioc);
#endif
if (zc.zc_nvlist_dst_filled) {
*resultp = fnvlist_unpack((void *)(uintptr_t)zc.zc_nvlist_dst,
zc.zc_nvlist_dst_size);
} else if (resultp != NULL) {
*resultp = NULL;
}
#ifdef __FreeBSD__
if (zfs_ioctl_version < ZFS_IOCVER_LZC)
lzc_compat_outnvl(&zc, ioc, resultp);
#endif
out:
#ifdef __FreeBSD__
if (zfs_ioctl_version < ZFS_IOCVER_LZC) {
if (source != oldsource)
nvlist_free(source);
source = oldsource;
}
#endif
fnvlist_pack_free(packed, size);
free((void *)(uintptr_t)zc.zc_nvlist_dst);
return (error);
}
int
lzc_create(const char *fsname, dmu_objset_type_t type, nvlist_t *props)
{
int error;
nvlist_t *args = fnvlist_alloc();
fnvlist_add_int32(args, "type", type);
if (props != NULL)
fnvlist_add_nvlist(args, "props", props);
error = lzc_ioctl(ZFS_IOC_CREATE, fsname, args, NULL);
nvlist_free(args);
return (error);
}
int
lzc_clone(const char *fsname, const char *origin,
nvlist_t *props)
{
int error;
nvlist_t *args = fnvlist_alloc();
fnvlist_add_string(args, "origin", origin);
if (props != NULL)
fnvlist_add_nvlist(args, "props", props);
error = lzc_ioctl(ZFS_IOC_CLONE, fsname, args, NULL);
nvlist_free(args);
return (error);
}
/*
* Creates snapshots.
*
* The keys in the snaps nvlist are the snapshots to be created.
* They must all be in the same pool.
*
* The props nvlist is properties to set. Currently only user properties
* are supported. { user:prop_name -> string value }
*
* The returned results nvlist will have an entry for each snapshot that failed.
* The value will be the (int32) error code.
*
* The return value will be 0 if all snapshots were created, otherwise it will
* be the errno of a (undetermined) snapshot that failed.
*/
int
lzc_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t **errlist)
{
nvpair_t *elem;
nvlist_t *args;
int error;
char pool[MAXNAMELEN];
*errlist = NULL;
/* determine the pool name */
elem = nvlist_next_nvpair(snaps, NULL);
if (elem == NULL)
return (0);
(void) strlcpy(pool, nvpair_name(elem), sizeof (pool));
pool[strcspn(pool, "/@")] = '\0';
args = fnvlist_alloc();
fnvlist_add_nvlist(args, "snaps", snaps);
if (props != NULL)
fnvlist_add_nvlist(args, "props", props);
error = lzc_ioctl(ZFS_IOC_SNAPSHOT, pool, args, errlist);
nvlist_free(args);
return (error);
}
/*
* Destroys snapshots.
*
* The keys in the snaps nvlist are the snapshots to be destroyed.
* They must all be in the same pool.
*
* Snapshots that do not exist will be silently ignored.
*
* If 'defer' is not set, and a snapshot has user holds or clones, the
* destroy operation will fail and none of the snapshots will be
* destroyed.
*
* If 'defer' is set, and a snapshot has user holds or clones, it will be
* marked for deferred destruction, and will be destroyed when the last hold
* or clone is removed/destroyed.
*
* The return value will be 0 if all snapshots were destroyed (or marked for
* later destruction if 'defer' is set) or didn't exist to begin with.
*
* Otherwise the return value will be the errno of a (undetermined) snapshot
* that failed, no snapshots will be destroyed, and the errlist will have an
* entry for each snapshot that failed. The value in the errlist will be
* the (int32) error code.
*/
int
lzc_destroy_snaps(nvlist_t *snaps, boolean_t defer, nvlist_t **errlist)
{
nvpair_t *elem;
nvlist_t *args;
int error;
char pool[MAXNAMELEN];
/* determine the pool name */
elem = nvlist_next_nvpair(snaps, NULL);
if (elem == NULL)
return (0);
(void) strlcpy(pool, nvpair_name(elem), sizeof (pool));
pool[strcspn(pool, "/@")] = '\0';
args = fnvlist_alloc();
fnvlist_add_nvlist(args, "snaps", snaps);
if (defer)
fnvlist_add_boolean(args, "defer");
error = lzc_ioctl(ZFS_IOC_DESTROY_SNAPS, pool, args, errlist);
nvlist_free(args);
return (error);
}
int
lzc_snaprange_space(const char *firstsnap, const char *lastsnap,
uint64_t *usedp)
{
nvlist_t *args;
nvlist_t *result;
int err;
char fs[MAXNAMELEN];
char *atp;
/* determine the fs name */
(void) strlcpy(fs, firstsnap, sizeof (fs));
atp = strchr(fs, '@');
if (atp == NULL)
return (EINVAL);
*atp = '\0';
args = fnvlist_alloc();
fnvlist_add_string(args, "firstsnap", firstsnap);
err = lzc_ioctl(ZFS_IOC_SPACE_SNAPS, lastsnap, args, &result);
nvlist_free(args);
if (err == 0)
*usedp = fnvlist_lookup_uint64(result, "used");
fnvlist_free(result);
return (err);
}
boolean_t
lzc_exists(const char *dataset)
{
/*
* The objset_stats ioctl is still legacy, so we need to construct our
* own zfs_cmd_t rather than using zfsc_ioctl().
*/
zfs_cmd_t zc = { 0 };
(void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name));
return (ioctl(g_fd, ZFS_IOC_OBJSET_STATS, &zc) == 0);
}
/*
* If fromsnap is NULL, a full (non-incremental) stream will be sent.
*/
int
lzc_send(const char *snapname, const char *fromsnap, int fd)
{
nvlist_t *args;
int err;
args = fnvlist_alloc();
fnvlist_add_int32(args, "fd", fd);
if (fromsnap != NULL)
fnvlist_add_string(args, "fromsnap", fromsnap);
err = lzc_ioctl(ZFS_IOC_SEND_NEW, snapname, args, NULL);
nvlist_free(args);
return (err);
}
/*
* If fromsnap is NULL, a full (non-incremental) stream will be estimated.
*/
int
lzc_send_space(const char *snapname, const char *fromsnap, uint64_t *spacep)
{
nvlist_t *args;
nvlist_t *result;
int err;
args = fnvlist_alloc();
if (fromsnap != NULL)
fnvlist_add_string(args, "fromsnap", fromsnap);
err = lzc_ioctl(ZFS_IOC_SEND_SPACE, snapname, args, &result);
nvlist_free(args);
if (err == 0)
*spacep = fnvlist_lookup_uint64(result, "space");
nvlist_free(result);
return (err);
}
static int
recv_read(int fd, void *buf, int ilen)
{
char *cp = buf;
int rv;
int len = ilen;
do {
rv = read(fd, cp, len);
cp += rv;
len -= rv;
} while (rv > 0);
if (rv < 0 || len != 0)
return (EIO);
return (0);
}
/*
* The simplest receive case: receive from the specified fd, creating the
* specified snapshot. Apply the specified properties a "received" properties
* (which can be overridden by locally-set properties). If the stream is a
* clone, its origin snapshot must be specified by 'origin'. The 'force'
* flag will cause the target filesystem to be rolled back or destroyed if
* necessary to receive.
*
* Return 0 on success or an errno on failure.
*
* Note: this interface does not work on dedup'd streams
* (those with DMU_BACKUP_FEATURE_DEDUP).
*/
int
lzc_receive(const char *snapname, nvlist_t *props, const char *origin,
boolean_t force, int fd)
{
/*
* The receive ioctl is still legacy, so we need to construct our own
* zfs_cmd_t rather than using zfsc_ioctl().
*/
zfs_cmd_t zc = { 0 };
char *atp;
char *packed = NULL;
size_t size;
dmu_replay_record_t drr;
int error;
ASSERT3S(g_refcount, >, 0);
/* zc_name is name of containing filesystem */
(void) strlcpy(zc.zc_name, snapname, sizeof (zc.zc_name));
atp = strchr(zc.zc_name, '@');
if (atp == NULL)
return (EINVAL);
*atp = '\0';
/* if the fs does not exist, try its parent. */
if (!lzc_exists(zc.zc_name)) {
char *slashp = strrchr(zc.zc_name, '/');
if (slashp == NULL)
return (ENOENT);
*slashp = '\0';
}
/* zc_value is full name of the snapshot to create */
(void) strlcpy(zc.zc_value, snapname, sizeof (zc.zc_value));
if (props != NULL) {
/* zc_nvlist_src is props to set */
packed = fnvlist_pack(props, &size);
zc.zc_nvlist_src = (uint64_t)(uintptr_t)packed;
zc.zc_nvlist_src_size = size;
}
/* zc_string is name of clone origin (if DRR_FLAG_CLONE) */
if (origin != NULL)
(void) strlcpy(zc.zc_string, origin, sizeof (zc.zc_string));
/* zc_begin_record is non-byteswapped BEGIN record */
error = recv_read(fd, &drr, sizeof (drr));
if (error != 0)
goto out;
zc.zc_begin_record = drr.drr_u.drr_begin;
/* zc_cookie is fd to read from */
zc.zc_cookie = fd;
/* zc guid is force flag */
zc.zc_guid = force;
/* zc_cleanup_fd is unused */
zc.zc_cleanup_fd = -1;
error = ioctl(g_fd, ZFS_IOC_RECV, &zc);
if (error != 0)
error = errno;
out:
if (packed != NULL)
fnvlist_pack_free(packed, size);
free((void*)(uintptr_t)zc.zc_nvlist_dst);
return (error);
}
|