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libzfs_sendrecv.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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <libdevinfo.h>
#include <libintl.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <stddef.h>
#include <fcntl.h>
#include <sys/mount.h>
#include <sys/mntent.h>
#include <sys/mnttab.h>
#include <sys/avl.h>
#include <stddef.h>

#include <libzfs.h>

#include "zfs_namecheck.h"
#include "zfs_prop.h"
#include "libzfs_impl.h"

#include <sys/zio_checksum.h>

static int zfs_receive_impl(libzfs_handle_t *, const char *, recvflags_t,
    int, avl_tree_t *, char **);

/*
 * Routines for dealing with the AVL tree of fs-nvlists
 */
typedef struct fsavl_node {
      avl_node_t fn_node;
      nvlist_t *fn_nvfs;
      char *fn_snapname;
      uint64_t fn_guid;
} fsavl_node_t;

static int
fsavl_compare(const void *arg1, const void *arg2)
{
      const fsavl_node_t *fn1 = arg1;
      const fsavl_node_t *fn2 = arg2;

      if (fn1->fn_guid > fn2->fn_guid)
            return (+1);
      else if (fn1->fn_guid < fn2->fn_guid)
            return (-1);
      else
            return (0);
}

/*
 * Given the GUID of a snapshot, find its containing filesystem and
 * (optionally) name.
 */
static nvlist_t *
fsavl_find(avl_tree_t *avl, uint64_t snapguid, char **snapname)
{
      fsavl_node_t fn_find;
      fsavl_node_t *fn;

      fn_find.fn_guid = snapguid;

      fn = avl_find(avl, &fn_find, NULL);
      if (fn) {
            if (snapname)
                  *snapname = fn->fn_snapname;
            return (fn->fn_nvfs);
      }
      return (NULL);
}

static void
fsavl_destroy(avl_tree_t *avl)
{
      fsavl_node_t *fn;
      void *cookie;

      if (avl == NULL)
            return;

      cookie = NULL;
      while ((fn = avl_destroy_nodes(avl, &cookie)) != NULL)
            free(fn);
      avl_destroy(avl);
      free(avl);
}

static avl_tree_t *
fsavl_create(nvlist_t *fss)
{
      avl_tree_t *fsavl;
      nvpair_t *fselem = NULL;

      if ((fsavl = malloc(sizeof (avl_tree_t))) == NULL)
            return (NULL);

      avl_create(fsavl, fsavl_compare, sizeof (fsavl_node_t),
          offsetof(fsavl_node_t, fn_node));

      while ((fselem = nvlist_next_nvpair(fss, fselem)) != NULL) {
            nvlist_t *nvfs, *snaps;
            nvpair_t *snapelem = NULL;

            VERIFY(0 == nvpair_value_nvlist(fselem, &nvfs));
            VERIFY(0 == nvlist_lookup_nvlist(nvfs, "snaps", &snaps));

            while ((snapelem =
                nvlist_next_nvpair(snaps, snapelem)) != NULL) {
                  fsavl_node_t *fn;
                  uint64_t guid;

                  VERIFY(0 == nvpair_value_uint64(snapelem, &guid));
                  if ((fn = malloc(sizeof (fsavl_node_t))) == NULL) {
                        fsavl_destroy(fsavl);
                        return (NULL);
                  }
                  fn->fn_nvfs = nvfs;
                  fn->fn_snapname = nvpair_name(snapelem);
                  fn->fn_guid = guid;

                  /*
                   * Note: if there are multiple snaps with the
                   * same GUID, we ignore all but one.
                   */
                  if (avl_find(fsavl, fn, NULL) == NULL)
                        avl_add(fsavl, fn);
                  else
                        free(fn);
            }
      }

      return (fsavl);
}

/*
 * Routines for dealing with the giant nvlist of fs-nvlists, etc.
 */
typedef struct send_data {
      uint64_t parent_fromsnap_guid;
      nvlist_t *parent_snaps;
      nvlist_t *fss;
      nvlist_t *snapprops;
      const char *fromsnap;
      const char *tosnap;

      /*
       * The header nvlist is of the following format:
       * {
       *   "tosnap" -> string
       *   "fromsnap" -> string (if incremental)
       *   "fss" -> {
       *    id -> {
       *
       *     "name" -> string (full name; for debugging)
       *     "parentfromsnap" -> number (guid of fromsnap in parent)
       *
       *     "props" -> { name -> value (only if set here) }
       *     "snaps" -> { name (lastname) -> number (guid) }
       *     "snapprops" -> { name (lastname) -> { name -> value } }
       *
       *     "origin" -> number (guid) (if clone)
       *     "sent" -> boolean (not on-disk)
       *    }
       *   }
       * }
       *
       */
} send_data_t;

static void send_iterate_prop(zfs_handle_t *zhp, nvlist_t *nv);

static int
send_iterate_snap(zfs_handle_t *zhp, void *arg)
{
      send_data_t *sd = arg;
      uint64_t guid = zhp->zfs_dmustats.dds_guid;
      char *snapname;
      nvlist_t *nv;

      snapname = strrchr(zhp->zfs_name, '@')+1;

      VERIFY(0 == nvlist_add_uint64(sd->parent_snaps, snapname, guid));
      /*
       * NB: if there is no fromsnap here (it's a newly created fs in
       * an incremental replication), we will substitute the tosnap.
       */
      if ((sd->fromsnap && strcmp(snapname, sd->fromsnap) == 0) ||
          (sd->parent_fromsnap_guid == 0 && sd->tosnap &&
          strcmp(snapname, sd->tosnap) == 0)) {
            sd->parent_fromsnap_guid = guid;
      }

      VERIFY(0 == nvlist_alloc(&nv, NV_UNIQUE_NAME, 0));
      send_iterate_prop(zhp, nv);
      VERIFY(0 == nvlist_add_nvlist(sd->snapprops, snapname, nv));
      nvlist_free(nv);

      zfs_close(zhp);
      return (0);
}

static void
send_iterate_prop(zfs_handle_t *zhp, nvlist_t *nv)
{
      nvpair_t *elem = NULL;

      while ((elem = nvlist_next_nvpair(zhp->zfs_props, elem)) != NULL) {
            char *propname = nvpair_name(elem);
            zfs_prop_t prop = zfs_name_to_prop(propname);
            nvlist_t *propnv;

            assert(zfs_prop_user(propname) || prop != ZPROP_INVAL);

            if (!zfs_prop_user(propname) && zfs_prop_readonly(prop))
                  continue;

            verify(nvpair_value_nvlist(elem, &propnv) == 0);
            if (prop == ZFS_PROP_QUOTA || prop == ZFS_PROP_RESERVATION) {
                  /* these guys are modifyable, but have no source */
                  uint64_t value;
                  verify(nvlist_lookup_uint64(propnv,
                      ZPROP_VALUE, &value) == 0);
                  if (zhp->zfs_type == ZFS_TYPE_SNAPSHOT)
                        continue;
            } else {
                  char *source;
                  if (nvlist_lookup_string(propnv,
                      ZPROP_SOURCE, &source) != 0)
                        continue;
                  if (strcmp(source, zhp->zfs_name) != 0)
                        continue;
            }

            if (zfs_prop_user(propname) ||
                zfs_prop_get_type(prop) == PROP_TYPE_STRING) {
                  char *value;
                  verify(nvlist_lookup_string(propnv,
                      ZPROP_VALUE, &value) == 0);
                  VERIFY(0 == nvlist_add_string(nv, propname, value));
            } else {
                  uint64_t value;
                  verify(nvlist_lookup_uint64(propnv,
                      ZPROP_VALUE, &value) == 0);
                  VERIFY(0 == nvlist_add_uint64(nv, propname, value));
            }
      }
}

static int
send_iterate_fs(zfs_handle_t *zhp, void *arg)
{
      send_data_t *sd = arg;
      nvlist_t *nvfs, *nv;
      int rv;
      uint64_t parent_fromsnap_guid_save = sd->parent_fromsnap_guid;
      uint64_t guid = zhp->zfs_dmustats.dds_guid;
      char guidstring[64];

      VERIFY(0 == nvlist_alloc(&nvfs, NV_UNIQUE_NAME, 0));
      VERIFY(0 == nvlist_add_string(nvfs, "name", zhp->zfs_name));
      VERIFY(0 == nvlist_add_uint64(nvfs, "parentfromsnap",
          sd->parent_fromsnap_guid));

      if (zhp->zfs_dmustats.dds_origin[0]) {
            zfs_handle_t *origin = zfs_open(zhp->zfs_hdl,
                zhp->zfs_dmustats.dds_origin, ZFS_TYPE_SNAPSHOT);
            if (origin == NULL)
                  return (-1);
            VERIFY(0 == nvlist_add_uint64(nvfs, "origin",
                origin->zfs_dmustats.dds_guid));
      }

      /* iterate over props */
      VERIFY(0 == nvlist_alloc(&nv, NV_UNIQUE_NAME, 0));
      send_iterate_prop(zhp, nv);
      VERIFY(0 == nvlist_add_nvlist(nvfs, "props", nv));
      nvlist_free(nv);

      /* iterate over snaps, and set sd->parent_fromsnap_guid */
      sd->parent_fromsnap_guid = 0;
      VERIFY(0 == nvlist_alloc(&sd->parent_snaps, NV_UNIQUE_NAME, 0));
      VERIFY(0 == nvlist_alloc(&sd->snapprops, NV_UNIQUE_NAME, 0));
      (void) zfs_iter_snapshots(zhp, send_iterate_snap, sd);
      VERIFY(0 == nvlist_add_nvlist(nvfs, "snaps", sd->parent_snaps));
      VERIFY(0 == nvlist_add_nvlist(nvfs, "snapprops", sd->snapprops));
      nvlist_free(sd->parent_snaps);
      nvlist_free(sd->snapprops);

      /* add this fs to nvlist */
      (void) snprintf(guidstring, sizeof (guidstring),
          "0x%llx", (longlong_t)guid);
      VERIFY(0 == nvlist_add_nvlist(sd->fss, guidstring, nvfs));
      nvlist_free(nvfs);

      /* iterate over children */
      rv = zfs_iter_filesystems(zhp, send_iterate_fs, sd);

      sd->parent_fromsnap_guid = parent_fromsnap_guid_save;

      zfs_close(zhp);
      return (rv);
}

static int
gather_nvlist(libzfs_handle_t *hdl, const char *fsname, const char *fromsnap,
    const char *tosnap, nvlist_t **nvlp, avl_tree_t **avlp)
{
      zfs_handle_t *zhp;
      send_data_t sd = { 0 };
      int error;

      zhp = zfs_open(hdl, fsname, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME);
      if (zhp == NULL)
            return (EZFS_BADTYPE);

      VERIFY(0 == nvlist_alloc(&sd.fss, NV_UNIQUE_NAME, 0));
      sd.fromsnap = fromsnap;
      sd.tosnap = tosnap;

      if ((error = send_iterate_fs(zhp, &sd)) != 0) {
            nvlist_free(sd.fss);
            if (avlp != NULL)
                  *avlp = NULL;
            *nvlp = NULL;
            return (error);
      }

      if (avlp != NULL && (*avlp = fsavl_create(sd.fss)) == NULL) {
            nvlist_free(sd.fss);
            *nvlp = NULL;
            return (EZFS_NOMEM);
      }

      *nvlp = sd.fss;
      return (0);
}

/*
 * Routines for dealing with the sorted snapshot functionality
 */
typedef struct zfs_node {
      zfs_handle_t      *zn_handle;
      avl_node_t  zn_avlnode;
} zfs_node_t;

static int
zfs_sort_snaps(zfs_handle_t *zhp, void *data)
{
      avl_tree_t *avl = data;
      zfs_node_t *node = zfs_alloc(zhp->zfs_hdl, sizeof (zfs_node_t));

      node->zn_handle = zhp;
      avl_add(avl, node);
      return (0);
}

/* ARGSUSED */
static int
zfs_snapshot_compare(const void *larg, const void *rarg)
{
      zfs_handle_t *l = ((zfs_node_t *)larg)->zn_handle;
      zfs_handle_t *r = ((zfs_node_t *)rarg)->zn_handle;
      uint64_t lcreate, rcreate;

      /*
       * Sort them according to creation time.  We use the hidden
       * CREATETXG property to get an absolute ordering of snapshots.
       */
      lcreate = zfs_prop_get_int(l, ZFS_PROP_CREATETXG);
      rcreate = zfs_prop_get_int(r, ZFS_PROP_CREATETXG);

      if (lcreate < rcreate)
            return (-1);
      else if (lcreate > rcreate)
            return (+1);
      else
            return (0);
}

static int
zfs_iter_snapshots_sorted(zfs_handle_t *zhp, zfs_iter_f callback, void *data)
{
      int ret = 0;
      zfs_node_t *node;
      avl_tree_t avl;
      void *cookie = NULL;

      avl_create(&avl, zfs_snapshot_compare,
          sizeof (zfs_node_t), offsetof(zfs_node_t, zn_avlnode));

      ret = zfs_iter_snapshots(zhp, zfs_sort_snaps, &avl);

      for (node = avl_first(&avl); node != NULL; node = AVL_NEXT(&avl, node))
            ret |= callback(node->zn_handle, data);

      while ((node = avl_destroy_nodes(&avl, &cookie)) != NULL)
            free(node);

      avl_destroy(&avl);

      return (ret);
}

/*
 * Routines specific to "zfs send"
 */
typedef struct send_dump_data {
      /* these are all just the short snapname (the part after the @) */
      const char *fromsnap;
      const char *tosnap;
      char lastsnap[ZFS_MAXNAMELEN];
      boolean_t seenfrom, seento, replicate, doall, fromorigin;
      boolean_t verbose;
      int outfd;
      boolean_t err;
      nvlist_t *fss;
      avl_tree_t *fsavl;
} send_dump_data_t;

/*
 * Dumps a backup of the given snapshot (incremental from fromsnap if it's not
 * NULL) to the file descriptor specified by outfd.
 */
static int
dump_ioctl(zfs_handle_t *zhp, const char *fromsnap, boolean_t fromorigin,
    int outfd)
{
      zfs_cmd_t zc = { 0 };
      libzfs_handle_t *hdl = zhp->zfs_hdl;

      assert(zhp->zfs_type == ZFS_TYPE_SNAPSHOT);
      assert(fromsnap == NULL || fromsnap[0] == '\0' || !fromorigin);

      (void) strlcpy(zc.zc_name, zhp->zfs_name, sizeof (zc.zc_name));
      if (fromsnap)
            (void) strlcpy(zc.zc_value, fromsnap, sizeof (zc.zc_value));
      zc.zc_cookie = outfd;
      zc.zc_obj = fromorigin;

      if (ioctl(zhp->zfs_hdl->libzfs_fd, ZFS_IOC_SEND, &zc) != 0) {
            char errbuf[1024];
            (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
                "warning: cannot send '%s'"), zhp->zfs_name);

            switch (errno) {

            case EXDEV:
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "not an earlier snapshot from the same fs"));
                  return (zfs_error(hdl, EZFS_CROSSTARGET, errbuf));

            case ENOENT:
                  if (zfs_dataset_exists(hdl, zc.zc_name,
                      ZFS_TYPE_SNAPSHOT)) {
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "incremental source (@%s) does not exist"),
                            zc.zc_value);
                  }
                  return (zfs_error(hdl, EZFS_NOENT, errbuf));

            case EDQUOT:
            case EFBIG:
            case EIO:
            case ENOLINK:
            case ENOSPC:
            case ENOSTR:
            case ENXIO:
            case EPIPE:
            case ERANGE:
            case EFAULT:
            case EROFS:
                  zfs_error_aux(hdl, strerror(errno));
                  return (zfs_error(hdl, EZFS_BADBACKUP, errbuf));

            default:
                  return (zfs_standard_error(hdl, errno, errbuf));
            }
      }

      return (0);
}

static int
dump_snapshot(zfs_handle_t *zhp, void *arg)
{
      send_dump_data_t *sdd = arg;
      const char *thissnap;
      int err;

      thissnap = strchr(zhp->zfs_name, '@') + 1;

      if (sdd->fromsnap && !sdd->seenfrom &&
          strcmp(sdd->fromsnap, thissnap) == 0) {
            sdd->seenfrom = B_TRUE;
            (void) strcpy(sdd->lastsnap, thissnap);
            zfs_close(zhp);
            return (0);
      }

      if (sdd->seento || !sdd->seenfrom) {
            zfs_close(zhp);
            return (0);
      }

      /* send it */
      if (sdd->verbose) {
            (void) fprintf(stderr, "sending from @%s to %s\n",
                sdd->lastsnap, zhp->zfs_name);
      }

      err = dump_ioctl(zhp, sdd->lastsnap,
          sdd->lastsnap[0] == '\0' && (sdd->fromorigin || sdd->replicate),
          sdd->outfd);

      if (!sdd->seento && strcmp(sdd->tosnap, thissnap) == 0)
            sdd->seento = B_TRUE;

      (void) strcpy(sdd->lastsnap, thissnap);
      zfs_close(zhp);
      return (err);
}

static int
dump_filesystem(zfs_handle_t *zhp, void *arg)
{
      int rv = 0;
      send_dump_data_t *sdd = arg;
      boolean_t missingfrom = B_FALSE;
      zfs_cmd_t zc = { 0 };

      (void) snprintf(zc.zc_name, sizeof (zc.zc_name), "%s@%s",
          zhp->zfs_name, sdd->tosnap);
      if (ioctl(zhp->zfs_hdl->libzfs_fd, ZFS_IOC_OBJSET_STATS, &zc) != 0) {
            (void) fprintf(stderr, "WARNING: "
                "could not send %s@%s: does not exist\n",
                zhp->zfs_name, sdd->tosnap);
            sdd->err = B_TRUE;
            return (0);
      }

      if (sdd->replicate && sdd->fromsnap) {
            /*
             * If this fs does not have fromsnap, and we're doing
             * recursive, we need to send a full stream from the
             * beginning (or an incremental from the origin if this
             * is a clone).  If we're doing non-recursive, then let
             * them get the error.
             */
            (void) snprintf(zc.zc_name, sizeof (zc.zc_name), "%s@%s",
                zhp->zfs_name, sdd->fromsnap);
            if (ioctl(zhp->zfs_hdl->libzfs_fd,
                ZFS_IOC_OBJSET_STATS, &zc) != 0) {
                  missingfrom = B_TRUE;
            }
      }

      if (sdd->doall) {
            sdd->seenfrom = sdd->seento = sdd->lastsnap[0] = 0;
            if (sdd->fromsnap == NULL || missingfrom)
                  sdd->seenfrom = B_TRUE;

            rv = zfs_iter_snapshots_sorted(zhp, dump_snapshot, arg);
            if (!sdd->seenfrom) {
                  (void) fprintf(stderr,
                      "WARNING: could not send %s@%s:\n"
                      "incremental source (%s@%s) does not exist\n",
                      zhp->zfs_name, sdd->tosnap,
                      zhp->zfs_name, sdd->fromsnap);
                  sdd->err = B_TRUE;
            } else if (!sdd->seento) {
                  if (sdd->fromsnap) {
                        (void) fprintf(stderr,
                            "WARNING: could not send %s@%s:\n"
                            "incremental source (%s@%s) "
                            "is not earlier than it\n",
                            zhp->zfs_name, sdd->tosnap,
                            zhp->zfs_name, sdd->fromsnap);
                  } else {
                        (void) fprintf(stderr, "WARNING: "
                            "could not send %s@%s: does not exist\n",
                            zhp->zfs_name, sdd->tosnap);
                  }
                  sdd->err = B_TRUE;
            }
      } else {
            zfs_handle_t *snapzhp;
            char snapname[ZFS_MAXNAMELEN];

            (void) snprintf(snapname, sizeof (snapname), "%s@%s",
                zfs_get_name(zhp), sdd->tosnap);
            snapzhp = zfs_open(zhp->zfs_hdl, snapname, ZFS_TYPE_SNAPSHOT);
            if (snapzhp == NULL) {
                  rv = -1;
            } else {
                  rv = dump_ioctl(snapzhp,
                      missingfrom ? NULL : sdd->fromsnap,
                      sdd->fromorigin || missingfrom,
                      sdd->outfd);
                  sdd->seento = B_TRUE;
                  zfs_close(snapzhp);
            }
      }

      return (rv);
}

static int
dump_filesystems(zfs_handle_t *rzhp, void *arg)
{
      send_dump_data_t *sdd = arg;
      nvpair_t *fspair;
      boolean_t needagain, progress;

      if (!sdd->replicate)
            return (dump_filesystem(rzhp, sdd));

again:
      needagain = progress = B_FALSE;
      for (fspair = nvlist_next_nvpair(sdd->fss, NULL); fspair;
          fspair = nvlist_next_nvpair(sdd->fss, fspair)) {
            nvlist_t *fslist;
            char *fsname;
            zfs_handle_t *zhp;
            int err;
            uint64_t origin_guid = 0;
            nvlist_t *origin_nv;

            VERIFY(nvpair_value_nvlist(fspair, &fslist) == 0);
            if (nvlist_lookup_boolean(fslist, "sent") == 0)
                  continue;

            VERIFY(nvlist_lookup_string(fslist, "name", &fsname) == 0);
            (void) nvlist_lookup_uint64(fslist, "origin", &origin_guid);

            origin_nv = fsavl_find(sdd->fsavl, origin_guid, NULL);
            if (origin_nv &&
                nvlist_lookup_boolean(origin_nv, "sent") == ENOENT) {
                  /*
                   * origin has not been sent yet;
                   * skip this clone.
                   */
                  needagain = B_TRUE;
                  continue;
            }

            zhp = zfs_open(rzhp->zfs_hdl, fsname, ZFS_TYPE_DATASET);
            if (zhp == NULL)
                  return (-1);
            err = dump_filesystem(zhp, sdd);
            VERIFY(nvlist_add_boolean(fslist, "sent") == 0);
            progress = B_TRUE;
            zfs_close(zhp);
            if (err)
                  return (err);
      }
      if (needagain) {
            assert(progress);
            goto again;
      }
      return (0);
}

/*
 * Dumps a backup of tosnap, incremental from fromsnap if it isn't NULL.
 * If 'doall', dump all intermediate snaps.
 * If 'replicate', dump special header and do recursively.
 */
int
zfs_send(zfs_handle_t *zhp, const char *fromsnap, const char *tosnap,
    boolean_t replicate, boolean_t doall, boolean_t fromorigin,
    boolean_t verbose, int outfd)
{
      char errbuf[1024];
      send_dump_data_t sdd = { 0 };
      int err;
      nvlist_t *fss = NULL;
      avl_tree_t *fsavl = NULL;

      (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
          "cannot send '%s'"), zhp->zfs_name);

      if (fromsnap && fromsnap[0] == '\0') {
            zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
                "zero-length incremental source"));
            return (zfs_error(zhp->zfs_hdl, EZFS_NOENT, errbuf));
      }

      if (replicate || doall) {
            dmu_replay_record_t drr = { 0 };
            char *packbuf = NULL;
            size_t buflen = 0;
            zio_cksum_t zc = { 0 };

            assert(fromsnap || doall);

            if (replicate) {
                  nvlist_t *hdrnv;

                  VERIFY(0 == nvlist_alloc(&hdrnv, NV_UNIQUE_NAME, 0));
                  if (fromsnap) {
                        VERIFY(0 == nvlist_add_string(hdrnv,
                            "fromsnap", fromsnap));
                  }
                  VERIFY(0 == nvlist_add_string(hdrnv, "tosnap", tosnap));

                  err = gather_nvlist(zhp->zfs_hdl, zhp->zfs_name,
                      fromsnap, tosnap, &fss, &fsavl);
                  if (err)
                        return (err);
                  VERIFY(0 == nvlist_add_nvlist(hdrnv, "fss", fss));
                  err = nvlist_pack(hdrnv, &packbuf, &buflen,
                      NV_ENCODE_XDR, 0);
                  nvlist_free(hdrnv);
                  if (err) {
                        fsavl_destroy(fsavl);
                        nvlist_free(fss);
                        return (zfs_standard_error(zhp->zfs_hdl,
                            err, errbuf));
                  }
            }

            /* write first begin record */
            drr.drr_type = DRR_BEGIN;
            drr.drr_u.drr_begin.drr_magic = DMU_BACKUP_MAGIC;
            drr.drr_u.drr_begin.drr_version = DMU_BACKUP_HEADER_VERSION;
            (void) snprintf(drr.drr_u.drr_begin.drr_toname,
                sizeof (drr.drr_u.drr_begin.drr_toname),
                "%s@%s", zhp->zfs_name, tosnap);
            drr.drr_payloadlen = buflen;
            fletcher_4_incremental_native(&drr, sizeof (drr), &zc);
            err = write(outfd, &drr, sizeof (drr));

            /* write header nvlist */
            if (err != -1) {
                  fletcher_4_incremental_native(packbuf, buflen, &zc);
                  err = write(outfd, packbuf, buflen);
            }
            free(packbuf);
            if (err == -1) {
                  fsavl_destroy(fsavl);
                  nvlist_free(fss);
                  return (zfs_standard_error(zhp->zfs_hdl,
                      errno, errbuf));
            }

            /* write end record */
            if (err != -1) {
                  bzero(&drr, sizeof (drr));
                  drr.drr_type = DRR_END;
                  drr.drr_u.drr_end.drr_checksum = zc;
                  err = write(outfd, &drr, sizeof (drr));
                  if (err == -1) {
                        fsavl_destroy(fsavl);
                        nvlist_free(fss);
                        return (zfs_standard_error(zhp->zfs_hdl,
                            errno, errbuf));
                  }
            }
      }

      /* dump each stream */
      sdd.fromsnap = fromsnap;
      sdd.tosnap = tosnap;
      sdd.outfd = outfd;
      sdd.replicate = replicate;
      sdd.doall = doall;
      sdd.fromorigin = fromorigin;
      sdd.fss = fss;
      sdd.fsavl = fsavl;
      sdd.verbose = verbose;
      err = dump_filesystems(zhp, &sdd);
      fsavl_destroy(fsavl);
      nvlist_free(fss);

      if (replicate || doall) {
            /*
             * write final end record.  NB: want to do this even if
             * there was some error, because it might not be totally
             * failed.
             */
            dmu_replay_record_t drr = { 0 };
            drr.drr_type = DRR_END;
            if (write(outfd, &drr, sizeof (drr)) == -1) {
                  return (zfs_standard_error(zhp->zfs_hdl,
                      errno, errbuf));
            }
      }

      return (err || sdd.err);
}

/*
 * Routines specific to "zfs recv"
 */

static int
recv_read(libzfs_handle_t *hdl, int fd, void *buf, int ilen,
    boolean_t byteswap, zio_cksum_t *zc)
{
      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) {
            zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                "failed to read from stream"));
            return (zfs_error(hdl, EZFS_BADSTREAM, dgettext(TEXT_DOMAIN,
                "cannot receive")));
      }

      if (zc) {
            if (byteswap)
                  fletcher_4_incremental_byteswap(buf, ilen, zc);
            else
                  fletcher_4_incremental_native(buf, ilen, zc);
      }
      return (0);
}

static int
recv_read_nvlist(libzfs_handle_t *hdl, int fd, int len, nvlist_t **nvp,
    boolean_t byteswap, zio_cksum_t *zc)
{
      char *buf;
      int err;

      buf = zfs_alloc(hdl, len);
      if (buf == NULL)
            return (ENOMEM);

      err = recv_read(hdl, fd, buf, len, byteswap, zc);
      if (err != 0) {
            free(buf);
            return (err);
      }

      err = nvlist_unpack(buf, len, nvp, 0);
      free(buf);
      if (err != 0) {
            zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "invalid "
                "stream (malformed nvlist)"));
            return (EINVAL);
      }
      return (0);
}

static int
recv_rename(libzfs_handle_t *hdl, const char *name, const char *tryname,
    int baselen, char *newname, recvflags_t flags)
{
      static int seq;
      zfs_cmd_t zc = { 0 };
      int err;
      prop_changelist_t *clp;
      zfs_handle_t *zhp;

      zhp = zfs_open(hdl, name, ZFS_TYPE_DATASET);
      if (zhp == NULL)
            return (-1);
      clp = changelist_gather(zhp, ZFS_PROP_NAME, 0,
          flags.force ? MS_FORCE : 0);
      zfs_close(zhp);
      if (clp == NULL)
            return (-1);
      err = changelist_prefix(clp);
      if (err)
            return (err);

      if (tryname) {
            (void) strcpy(newname, tryname);

            zc.zc_objset_type = DMU_OST_ZFS;
            (void) strlcpy(zc.zc_name, name, sizeof (zc.zc_name));
            (void) strlcpy(zc.zc_value, tryname, sizeof (zc.zc_value));

            if (flags.verbose) {
                  (void) printf("attempting rename %s to %s\n",
                      zc.zc_name, zc.zc_value);
            }
            err = ioctl(hdl->libzfs_fd, ZFS_IOC_RENAME, &zc);
            if (err == 0)
                  changelist_rename(clp, name, tryname);
      } else {
            err = ENOENT;
      }

      if (err != 0 && strncmp(name+baselen, "recv-", 5) != 0) {
            seq++;

            (void) strncpy(newname, name, baselen);
            (void) snprintf(newname+baselen, ZFS_MAXNAMELEN-baselen,
                "recv-%u-%u", getpid(), seq);
            (void) strlcpy(zc.zc_value, newname, sizeof (zc.zc_value));

            if (flags.verbose) {
                  (void) printf("failed - trying rename %s to %s\n",
                      zc.zc_name, zc.zc_value);
            }
            err = ioctl(hdl->libzfs_fd, ZFS_IOC_RENAME, &zc);
            if (err == 0)
                  changelist_rename(clp, name, newname);
            if (err && flags.verbose) {
                  (void) printf("failed (%u) - "
                      "will try again on next pass\n", errno);
            }
            err = EAGAIN;
      } else if (flags.verbose) {
            if (err == 0)
                  (void) printf("success\n");
            else
                  (void) printf("failed (%u)\n", errno);
      }

      (void) changelist_postfix(clp);
      changelist_free(clp);

      return (err);
}

static int
recv_destroy(libzfs_handle_t *hdl, const char *name, int baselen,
    char *newname, recvflags_t flags)
{
      zfs_cmd_t zc = { 0 };
      int err = 0;
      prop_changelist_t *clp;
      zfs_handle_t *zhp;

      zhp = zfs_open(hdl, name, ZFS_TYPE_DATASET);
      if (zhp == NULL)
            return (-1);
      clp = changelist_gather(zhp, ZFS_PROP_NAME, 0,
          flags.force ? MS_FORCE : 0);
      zfs_close(zhp);
      if (clp == NULL)
            return (-1);
      err = changelist_prefix(clp);
      if (err)
            return (err);

      zc.zc_objset_type = DMU_OST_ZFS;
      (void) strlcpy(zc.zc_name, name, sizeof (zc.zc_name));

      if (flags.verbose)
            (void) printf("attempting destroy %s\n", zc.zc_name);
      err = ioctl(hdl->libzfs_fd, ZFS_IOC_DESTROY, &zc);

      if (err == 0) {
            if (flags.verbose)
                  (void) printf("success\n");
            changelist_remove(clp, zc.zc_name);
      }

      (void) changelist_postfix(clp);
      changelist_free(clp);

      if (err != 0)
            err = recv_rename(hdl, name, NULL, baselen, newname, flags);

      return (err);
}

typedef struct guid_to_name_data {
      uint64_t guid;
      char *name;
} guid_to_name_data_t;

static int
guid_to_name_cb(zfs_handle_t *zhp, void *arg)
{
      guid_to_name_data_t *gtnd = arg;
      int err;

      if (zhp->zfs_dmustats.dds_guid == gtnd->guid) {
            (void) strcpy(gtnd->name, zhp->zfs_name);
            return (EEXIST);
      }
      err = zfs_iter_children(zhp, guid_to_name_cb, gtnd);
      zfs_close(zhp);
      return (err);
}

static int
guid_to_name(libzfs_handle_t *hdl, const char *parent, uint64_t guid,
    char *name)
{
      /* exhaustive search all local snapshots */
      guid_to_name_data_t gtnd;
      int err = 0;
      zfs_handle_t *zhp;
      char *cp;

      gtnd.guid = guid;
      gtnd.name = name;

      if (strchr(parent, '@') == NULL) {
            zhp = make_dataset_handle(hdl, parent);
            if (zhp != NULL) {
                  err = zfs_iter_children(zhp, guid_to_name_cb, &gtnd);
                  zfs_close(zhp);
                  if (err == EEXIST)
                        return (0);
            }
      }

      cp = strchr(parent, '/');
      if (cp)
            *cp = '\0';
      zhp = make_dataset_handle(hdl, parent);
      if (cp)
            *cp = '/';

      if (zhp) {
            err = zfs_iter_children(zhp, guid_to_name_cb, &gtnd);
            zfs_close(zhp);
      }

      return (err == EEXIST ? 0 : ENOENT);

}

/*
 * Return true if dataset guid1 is created before guid2.
 */
static int
created_before(libzfs_handle_t *hdl, avl_tree_t *avl,
    uint64_t guid1, uint64_t guid2)
{
      nvlist_t *nvfs;
      char *fsname, *snapname;
      char buf[ZFS_MAXNAMELEN];
      int rv;
      zfs_node_t zn1, zn2;

      if (guid2 == 0)
            return (0);
      if (guid1 == 0)
            return (1);

      nvfs = fsavl_find(avl, guid1, &snapname);
      VERIFY(0 == nvlist_lookup_string(nvfs, "name", &fsname));
      (void) snprintf(buf, sizeof (buf), "%s@%s", fsname, snapname);
      zn1.zn_handle = zfs_open(hdl, buf, ZFS_TYPE_SNAPSHOT);
      if (zn1.zn_handle == NULL)
            return (-1);

      nvfs = fsavl_find(avl, guid2, &snapname);
      VERIFY(0 == nvlist_lookup_string(nvfs, "name", &fsname));
      (void) snprintf(buf, sizeof (buf), "%s@%s", fsname, snapname);
      zn2.zn_handle = zfs_open(hdl, buf, ZFS_TYPE_SNAPSHOT);
      if (zn2.zn_handle == NULL) {
            zfs_close(zn2.zn_handle);
            return (-1);
      }

      rv = (zfs_snapshot_compare(&zn1, &zn2) == -1);

      zfs_close(zn1.zn_handle);
      zfs_close(zn2.zn_handle);

      return (rv);
}

static int
recv_incremental_replication(libzfs_handle_t *hdl, const char *tofs,
    recvflags_t flags, nvlist_t *stream_nv, avl_tree_t *stream_avl)
{
      nvlist_t *local_nv;
      avl_tree_t *local_avl;
      nvpair_t *fselem, *nextfselem;
      char *tosnap, *fromsnap;
      char newname[ZFS_MAXNAMELEN];
      int error;
      boolean_t needagain, progress;

      VERIFY(0 == nvlist_lookup_string(stream_nv, "fromsnap", &fromsnap));
      VERIFY(0 == nvlist_lookup_string(stream_nv, "tosnap", &tosnap));

      if (flags.dryrun)
            return (0);

again:
      needagain = progress = B_FALSE;

      if ((error = gather_nvlist(hdl, tofs, fromsnap, NULL,
          &local_nv, &local_avl)) != 0)
            return (error);

      /*
       * Process deletes and renames
       */
      for (fselem = nvlist_next_nvpair(local_nv, NULL);
          fselem; fselem = nextfselem) {
            nvlist_t *nvfs, *snaps;
            nvlist_t *stream_nvfs = NULL;
            nvpair_t *snapelem, *nextsnapelem;
            uint64_t fromguid = 0;
            uint64_t originguid = 0;
            uint64_t stream_originguid = 0;
            uint64_t parent_fromsnap_guid, stream_parent_fromsnap_guid;
            char *fsname, *stream_fsname;

            nextfselem = nvlist_next_nvpair(local_nv, fselem);

            VERIFY(0 == nvpair_value_nvlist(fselem, &nvfs));
            VERIFY(0 == nvlist_lookup_nvlist(nvfs, "snaps", &snaps));
            VERIFY(0 == nvlist_lookup_string(nvfs, "name", &fsname));
            VERIFY(0 == nvlist_lookup_uint64(nvfs, "parentfromsnap",
                &parent_fromsnap_guid));
            (void) nvlist_lookup_uint64(nvfs, "origin", &originguid);

            /*
             * First find the stream's fs, so we can check for
             * a different origin (due to "zfs promote")
             */
            for (snapelem = nvlist_next_nvpair(snaps, NULL);
                snapelem; snapelem = nvlist_next_nvpair(snaps, snapelem)) {
                  uint64_t thisguid;

                  VERIFY(0 == nvpair_value_uint64(snapelem, &thisguid));
                  stream_nvfs = fsavl_find(stream_avl, thisguid, NULL);

                  if (stream_nvfs != NULL)
                        break;
            }

            /* check for promote */
            (void) nvlist_lookup_uint64(stream_nvfs, "origin",
                &stream_originguid);
            if (stream_nvfs && originguid != stream_originguid) {
                  switch (created_before(hdl, local_avl,
                      stream_originguid, originguid)) {
                  case 1: {
                        /* promote it! */
                        zfs_cmd_t zc = { 0 };
                        nvlist_t *origin_nvfs;
                        char *origin_fsname;

                        if (flags.verbose)
                              (void) printf("promoting %s\n", fsname);

                        origin_nvfs = fsavl_find(local_avl, originguid,
                            NULL);
                        VERIFY(0 == nvlist_lookup_string(origin_nvfs,
                            "name", &origin_fsname));
                        (void) strlcpy(zc.zc_value, origin_fsname,
                            sizeof (zc.zc_value));
                        (void) strlcpy(zc.zc_name, fsname,
                            sizeof (zc.zc_name));
                        error = zfs_ioctl(hdl, ZFS_IOC_PROMOTE, &zc);
                        if (error == 0)
                              progress = B_TRUE;
                        break;
                  }
                  default:
                        break;
                  case -1:
                        fsavl_destroy(local_avl);
                        nvlist_free(local_nv);
                        return (-1);
                  }
                  /*
                   * We had/have the wrong origin, therefore our
                   * list of snapshots is wrong.  Need to handle
                   * them on the next pass.
                   */
                  needagain = B_TRUE;
                  continue;
            }

            for (snapelem = nvlist_next_nvpair(snaps, NULL);
                snapelem; snapelem = nextsnapelem) {
                  uint64_t thisguid;
                  char *stream_snapname;
                  nvlist_t *found, *props;

                  nextsnapelem = nvlist_next_nvpair(snaps, snapelem);

                  VERIFY(0 == nvpair_value_uint64(snapelem, &thisguid));
                  found = fsavl_find(stream_avl, thisguid,
                      &stream_snapname);

                  /* check for delete */
                  if (found == NULL) {
                        char name[ZFS_MAXNAMELEN];

                        if (!flags.force)
                              continue;

                        (void) snprintf(name, sizeof (name), "%s@%s",
                            fsname, nvpair_name(snapelem));

                        error = recv_destroy(hdl, name,
                            strlen(fsname)+1, newname, flags);
                        if (error)
                              needagain = B_TRUE;
                        else
                              progress = B_TRUE;
                        continue;
                  }

                  stream_nvfs = found;

                  if (0 == nvlist_lookup_nvlist(stream_nvfs, "snapprops",
                      &props) && 0 == nvlist_lookup_nvlist(props,
                      stream_snapname, &props)) {
                        zfs_cmd_t zc = { 0 };

                        zc.zc_cookie = B_TRUE; /* clear current props */
                        (void) snprintf(zc.zc_name, sizeof (zc.zc_name),
                            "%s@%s", fsname, nvpair_name(snapelem));
                        if (zcmd_write_src_nvlist(hdl, &zc,
                            props) == 0) {
                              (void) zfs_ioctl(hdl,
                                  ZFS_IOC_SET_PROP, &zc);
                              zcmd_free_nvlists(&zc);
                        }
                  }

                  /* check for different snapname */
                  if (strcmp(nvpair_name(snapelem),
                      stream_snapname) != 0) {
                        char name[ZFS_MAXNAMELEN];
                        char tryname[ZFS_MAXNAMELEN];

                        (void) snprintf(name, sizeof (name), "%s@%s",
                            fsname, nvpair_name(snapelem));
                        (void) snprintf(tryname, sizeof (name), "%s@%s",
                            fsname, stream_snapname);

                        error = recv_rename(hdl, name, tryname,
                            strlen(fsname)+1, newname, flags);
                        if (error)
                              needagain = B_TRUE;
                        else
                              progress = B_TRUE;
                  }

                  if (strcmp(stream_snapname, fromsnap) == 0)
                        fromguid = thisguid;
            }

            /* check for delete */
            if (stream_nvfs == NULL) {
                  if (!flags.force)
                        continue;

                  error = recv_destroy(hdl, fsname, strlen(tofs)+1,
                      newname, flags);
                  if (error)
                        needagain = B_TRUE;
                  else
                        progress = B_TRUE;
                  continue;
            }

            if (fromguid == 0 && flags.verbose) {
                  (void) printf("local fs %s does not have fromsnap "
                      "(%s in stream); must have been deleted locally; "
                      "ignoring\n", fsname, fromsnap);
                  continue;
            }

            VERIFY(0 == nvlist_lookup_string(stream_nvfs,
                "name", &stream_fsname));
            VERIFY(0 == nvlist_lookup_uint64(stream_nvfs,
                "parentfromsnap", &stream_parent_fromsnap_guid));

            /* check for rename */
            if ((stream_parent_fromsnap_guid != 0 &&
                stream_parent_fromsnap_guid != parent_fromsnap_guid) ||
                strcmp(strrchr(fsname, '/'),
                strrchr(stream_fsname, '/')) != 0) {
                  nvlist_t *parent;
                  char tryname[ZFS_MAXNAMELEN];

                  parent = fsavl_find(local_avl,
                      stream_parent_fromsnap_guid, NULL);
                  /*
                   * NB: parent might not be found if we used the
                   * tosnap for stream_parent_fromsnap_guid,
                   * because the parent is a newly-created fs;
                   * we'll be able to rename it after we recv the
                   * new fs.
                   */
                  if (parent != NULL) {
                        char *pname;

                        VERIFY(0 == nvlist_lookup_string(parent, "name",
                            &pname));
                        (void) snprintf(tryname, sizeof (tryname),
                            "%s%s", pname, strrchr(stream_fsname, '/'));
                  } else {
                        tryname[0] = '\0';
                        if (flags.verbose) {
                              (void) printf("local fs %s new parent "
                                  "not found\n", fsname);
                        }
                  }

                  error = recv_rename(hdl, fsname, tryname,
                      strlen(tofs)+1, newname, flags);
                  if (error)
                        needagain = B_TRUE;
                  else
                        progress = B_TRUE;
            }
      }

      fsavl_destroy(local_avl);
      nvlist_free(local_nv);

      if (needagain && progress) {
            /* do another pass to fix up temporary names */
            if (flags.verbose)
                  (void) printf("another pass:\n");
            goto again;
      }

      return (needagain);
}

static int
zfs_receive_package(libzfs_handle_t *hdl, int fd, const char *destname,
    recvflags_t flags, dmu_replay_record_t *drr, zio_cksum_t *zc,
    char **top_zfs)
{
      nvlist_t *stream_nv = NULL;
      avl_tree_t *stream_avl = NULL;
      char *fromsnap = NULL;
      char tofs[ZFS_MAXNAMELEN];
      char errbuf[1024];
      dmu_replay_record_t drre;
      int error;
      boolean_t anyerr = B_FALSE;
      boolean_t softerr = B_FALSE;

      (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
          "cannot receive"));

      if (strchr(destname, '@')) {
            zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                "can not specify snapshot name for multi-snapshot stream"));
            return (zfs_error(hdl, EZFS_BADSTREAM, errbuf));
      }

      assert(drr->drr_type == DRR_BEGIN);
      assert(drr->drr_u.drr_begin.drr_magic == DMU_BACKUP_MAGIC);
      assert(drr->drr_u.drr_begin.drr_version == DMU_BACKUP_HEADER_VERSION);

      /*
       * Read in the nvlist from the stream.
       */
      if (drr->drr_payloadlen != 0) {
            if (!flags.isprefix) {
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "must use -d to receive replication "
                      "(send -R) stream"));
                  return (zfs_error(hdl, EZFS_BADSTREAM, errbuf));
            }

            error = recv_read_nvlist(hdl, fd, drr->drr_payloadlen,
                &stream_nv, flags.byteswap, zc);
            if (error) {
                  error = zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                  goto out;
            }
      }

      /*
       * Read in the end record and verify checksum.
       */
      if (0 != (error = recv_read(hdl, fd, &drre, sizeof (drre),
          flags.byteswap, NULL)))
            goto out;
      if (flags.byteswap) {
            drre.drr_type = BSWAP_32(drre.drr_type);
            drre.drr_u.drr_end.drr_checksum.zc_word[0] =
                BSWAP_64(drre.drr_u.drr_end.drr_checksum.zc_word[0]);
            drre.drr_u.drr_end.drr_checksum.zc_word[1] =
                BSWAP_64(drre.drr_u.drr_end.drr_checksum.zc_word[1]);
            drre.drr_u.drr_end.drr_checksum.zc_word[2] =
                BSWAP_64(drre.drr_u.drr_end.drr_checksum.zc_word[2]);
            drre.drr_u.drr_end.drr_checksum.zc_word[3] =
                BSWAP_64(drre.drr_u.drr_end.drr_checksum.zc_word[3]);
      }
      if (drre.drr_type != DRR_END) {
            error = zfs_error(hdl, EZFS_BADSTREAM, errbuf);
            goto out;
      }
      if (!ZIO_CHECKSUM_EQUAL(drre.drr_u.drr_end.drr_checksum, *zc)) {
            zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                "incorrect header checksum"));
            error = zfs_error(hdl, EZFS_BADSTREAM, errbuf);
            goto out;
      }

      (void) nvlist_lookup_string(stream_nv, "fromsnap", &fromsnap);

      if (drr->drr_payloadlen != 0) {
            nvlist_t *stream_fss;

            VERIFY(0 == nvlist_lookup_nvlist(stream_nv, "fss",
                &stream_fss));
            if ((stream_avl = fsavl_create(stream_fss)) == NULL) {
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "couldn't allocate avl tree"));
                  error = zfs_error(hdl, EZFS_NOMEM, errbuf);
                  goto out;
            }

            if (fromsnap != NULL) {
                  (void) strlcpy(tofs, destname, ZFS_MAXNAMELEN);
                  if (flags.isprefix) {
                        int i = strcspn(drr->drr_u.drr_begin.drr_toname,
                            "/@");
                        /* zfs_receive_one() will create_parents() */
                        (void) strlcat(tofs,
                            &drr->drr_u.drr_begin.drr_toname[i],
                            ZFS_MAXNAMELEN);
                        *strchr(tofs, '@') = '\0';
                  }
                  softerr = recv_incremental_replication(hdl, tofs,
                      flags, stream_nv, stream_avl);
            }
      }


      /* Finally, receive each contained stream */
      do {
            /*
             * we should figure out if it has a recoverable
             * error, in which case do a recv_skip() and drive on.
             * Note, if we fail due to already having this guid,
             * zfs_receive_one() will take care of it (ie,
             * recv_skip() and return 0).
             */
            error = zfs_receive_impl(hdl, destname, flags, fd,
                stream_avl, top_zfs);
            if (error == ENODATA) {
                  error = 0;
                  break;
            }
            anyerr |= error;
      } while (error == 0);

      if (drr->drr_payloadlen != 0 && fromsnap != NULL) {
            /*
             * Now that we have the fs's they sent us, try the
             * renames again.
             */
            softerr = recv_incremental_replication(hdl, tofs, flags,
                stream_nv, stream_avl);
      }

out:
      fsavl_destroy(stream_avl);
      if (stream_nv)
            nvlist_free(stream_nv);
      if (softerr)
            error = -2;
      if (anyerr)
            error = -1;
      return (error);
}

static int
recv_skip(libzfs_handle_t *hdl, int fd, boolean_t byteswap)
{
      dmu_replay_record_t *drr;
      void *buf = malloc(1<<20);

      /* XXX would be great to use lseek if possible... */
      drr = buf;

      while (recv_read(hdl, fd, drr, sizeof (dmu_replay_record_t),
          byteswap, NULL) == 0) {
            if (byteswap)
                  drr->drr_type = BSWAP_32(drr->drr_type);

            switch (drr->drr_type) {
            case DRR_BEGIN:
                  /* NB: not to be used on v2 stream packages */
                  assert(drr->drr_payloadlen == 0);
                  break;

            case DRR_END:
                  free(buf);
                  return (0);

            case DRR_OBJECT:
                  if (byteswap) {
                        drr->drr_u.drr_object.drr_bonuslen =
                            BSWAP_32(drr->drr_u.drr_object.
                            drr_bonuslen);
                  }
                  (void) recv_read(hdl, fd, buf,
                      P2ROUNDUP(drr->drr_u.drr_object.drr_bonuslen, 8),
                      B_FALSE, NULL);
                  break;

            case DRR_WRITE:
                  if (byteswap) {
                        drr->drr_u.drr_write.drr_length =
                            BSWAP_64(drr->drr_u.drr_write.drr_length);
                  }
                  (void) recv_read(hdl, fd, buf,
                      drr->drr_u.drr_write.drr_length, B_FALSE, NULL);
                  break;

            case DRR_FREEOBJECTS:
            case DRR_FREE:
                  break;

            default:
                  assert(!"invalid record type");
            }
      }

      free(buf);
      return (-1);
}

/*
 * Restores a backup of tosnap from the file descriptor specified by infd.
 */
static int
zfs_receive_one(libzfs_handle_t *hdl, int infd, const char *tosnap,
    recvflags_t flags, dmu_replay_record_t *drr,
    dmu_replay_record_t *drr_noswap, avl_tree_t *stream_avl,
    char **top_zfs)
{
      zfs_cmd_t zc = { 0 };
      time_t begin_time;
      int ioctl_err, ioctl_errno, err, choplen;
      char *cp;
      struct drr_begin *drrb = &drr->drr_u.drr_begin;
      char errbuf[1024];
      char chopprefix[ZFS_MAXNAMELEN];
      boolean_t newfs = B_FALSE;
      boolean_t stream_wantsnewfs;
      uint64_t parent_snapguid = 0;
      prop_changelist_t *clp = NULL;
      nvlist_t *snapprops_nvlist = NULL;

      begin_time = time(NULL);

      (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
          "cannot receive"));

      if (stream_avl != NULL) {
            char *snapname;
            nvlist_t *fs = fsavl_find(stream_avl, drrb->drr_toguid,
                &snapname);
            nvlist_t *props;
            int ret;

            (void) nvlist_lookup_uint64(fs, "parentfromsnap",
                &parent_snapguid);
            err = nvlist_lookup_nvlist(fs, "props", &props);
            if (err)
                  VERIFY(0 == nvlist_alloc(&props, NV_UNIQUE_NAME, 0));

            if (flags.canmountoff) {
                  VERIFY(0 == nvlist_add_uint64(props,
                      zfs_prop_to_name(ZFS_PROP_CANMOUNT), 0));
            }
            ret = zcmd_write_src_nvlist(hdl, &zc, props);
            if (err)
                  nvlist_free(props);

            if (0 == nvlist_lookup_nvlist(fs, "snapprops", &props)) {
                  VERIFY(0 == nvlist_lookup_nvlist(props,
                      snapname, &snapprops_nvlist));
            }

            if (ret != 0)
                  return (-1);
      }

      /*
       * Determine how much of the snapshot name stored in the stream
       * we are going to tack on to the name they specified on the
       * command line, and how much we are going to chop off.
       *
       * If they specified a snapshot, chop the entire name stored in
       * the stream.
       */
      (void) strcpy(chopprefix, drrb->drr_toname);
      if (flags.isprefix) {
            /*
             * They specified a fs with -d, we want to tack on
             * everything but the pool name stored in the stream
             */
            if (strchr(tosnap, '@')) {
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "invalid "
                      "argument - snapshot not allowed with -d"));
                  return (zfs_error(hdl, EZFS_INVALIDNAME, errbuf));
            }
            cp = strchr(chopprefix, '/');
            if (cp == NULL)
                  cp = strchr(chopprefix, '@');
            *cp = '\0';
      } else if (strchr(tosnap, '@') == NULL) {
            /*
             * If they specified a filesystem without -d, we want to
             * tack on everything after the fs specified in the
             * first name from the stream.
             */
            cp = strchr(chopprefix, '@');
            *cp = '\0';
      }
      choplen = strlen(chopprefix);

      /*
       * Determine name of destination snapshot, store in zc_value.
       */
      (void) strcpy(zc.zc_value, tosnap);
      (void) strncat(zc.zc_value, drrb->drr_toname+choplen,
          sizeof (zc.zc_value));
      if (!zfs_name_valid(zc.zc_value, ZFS_TYPE_SNAPSHOT)) {
            zcmd_free_nvlists(&zc);
            return (zfs_error(hdl, EZFS_INVALIDNAME, errbuf));
      }

      /*
       * Determine the name of the origin snapshot, store in zc_string.
       */
      if (drrb->drr_flags & DRR_FLAG_CLONE) {
            if (guid_to_name(hdl, tosnap,
                drrb->drr_fromguid, zc.zc_string) != 0) {
                  zcmd_free_nvlists(&zc);
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "local origin for clone %s does not exist"),
                      zc.zc_value);
                  return (zfs_error(hdl, EZFS_NOENT, errbuf));
            }
            if (flags.verbose)
                  (void) printf("found clone origin %s\n", zc.zc_string);
      }

      stream_wantsnewfs = (drrb->drr_fromguid == 0 ||
          (drrb->drr_flags & DRR_FLAG_CLONE));

      if (stream_wantsnewfs) {
            /*
             * if the parent fs does not exist, look for it based on
             * the parent snap GUID
             */
            (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
                "cannot receive new filesystem stream"));

            (void) strcpy(zc.zc_name, zc.zc_value);
            cp = strrchr(zc.zc_name, '/');
            if (cp)
                  *cp = '\0';
            if (cp &&
                !zfs_dataset_exists(hdl, zc.zc_name, ZFS_TYPE_DATASET)) {
                  char suffix[ZFS_MAXNAMELEN];
                  (void) strcpy(suffix, strrchr(zc.zc_value, '/'));
                  if (guid_to_name(hdl, tosnap, parent_snapguid,
                      zc.zc_value) == 0) {
                        *strchr(zc.zc_value, '@') = '\0';
                        (void) strcat(zc.zc_value, suffix);
                  }
            }
      } else {
            /*
             * if the fs does not exist, look for it based on the
             * fromsnap GUID
             */
            (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
                "cannot receive incremental stream"));

            (void) strcpy(zc.zc_name, zc.zc_value);
            *strchr(zc.zc_name, '@') = '\0';

            if (!zfs_dataset_exists(hdl, zc.zc_name, ZFS_TYPE_DATASET)) {
                  char snap[ZFS_MAXNAMELEN];
                  (void) strcpy(snap, strchr(zc.zc_value, '@'));
                  if (guid_to_name(hdl, tosnap, drrb->drr_fromguid,
                      zc.zc_value) == 0) {
                        *strchr(zc.zc_value, '@') = '\0';
                        (void) strcat(zc.zc_value, snap);
                  }
            }
      }

      (void) strcpy(zc.zc_name, zc.zc_value);
      *strchr(zc.zc_name, '@') = '\0';

      if (zfs_dataset_exists(hdl, zc.zc_name, ZFS_TYPE_DATASET)) {
            zfs_handle_t *zhp;
            /*
             * Destination fs exists.  Therefore this should either
             * be an incremental, or the stream specifies a new fs
             * (full stream or clone) and they want us to blow it
             * away (and have therefore specified -F and removed any
             * snapshots).
             */

            if (stream_wantsnewfs) {
                  if (!flags.force) {
                        zcmd_free_nvlists(&zc);
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "destination '%s' exists\n"
                            "must specify -F to overwrite it"),
                            zc.zc_name);
                        return (zfs_error(hdl, EZFS_EXISTS, errbuf));
                  }
                  if (ioctl(hdl->libzfs_fd, ZFS_IOC_SNAPSHOT_LIST_NEXT,
                      &zc) == 0) {
                        zcmd_free_nvlists(&zc);
                        zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                            "destination has snapshots (eg. %s)\n"
                            "must destroy them to overwrite it"),
                            zc.zc_name);
                        return (zfs_error(hdl, EZFS_EXISTS, errbuf));
                  }
            }

            if ((zhp = zfs_open(hdl, zc.zc_name,
                ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME)) == NULL) {
                  zcmd_free_nvlists(&zc);
                  return (-1);
            }

            if (stream_wantsnewfs &&
                zhp->zfs_dmustats.dds_origin[0]) {
                  zcmd_free_nvlists(&zc);
                  zfs_close(zhp);
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "destination '%s' is a clone\n"
                      "must destroy it to overwrite it"),
                      zc.zc_name);
                  return (zfs_error(hdl, EZFS_EXISTS, errbuf));
            }

            if (!flags.dryrun && zhp->zfs_type == ZFS_TYPE_FILESYSTEM &&
                stream_wantsnewfs) {
                  /* We can't do online recv in this case */
                  clp = changelist_gather(zhp, ZFS_PROP_NAME, 0, 0);
                  if (clp == NULL) {
                        zcmd_free_nvlists(&zc);
                        return (-1);
                  }
                  if (changelist_prefix(clp) != 0) {
                        changelist_free(clp);
                        zcmd_free_nvlists(&zc);
                        return (-1);
                  }
            }
            if (!flags.dryrun && zhp->zfs_type == ZFS_TYPE_VOLUME &&
                zvol_remove_link(hdl, zhp->zfs_name) != 0) {
                  zfs_close(zhp);
                  zcmd_free_nvlists(&zc);
                  return (-1);
            }
            zfs_close(zhp);
      } else {
            /*
             * Destination filesystem does not exist.  Therefore we better
             * be creating a new filesystem (either from a full backup, or
             * a clone).  It would therefore be invalid if the user
             * specified only the pool name (i.e. if the destination name
             * contained no slash character).
             */
            if (!stream_wantsnewfs ||
                (cp = strrchr(zc.zc_name, '/')) == NULL) {
                  zcmd_free_nvlists(&zc);
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "destination '%s' does not exist"), zc.zc_name);
                  return (zfs_error(hdl, EZFS_NOENT, errbuf));
            }

            /*
             * Trim off the final dataset component so we perform the
             * recvbackup ioctl to the filesystems's parent.
             */
            *cp = '\0';

            if (flags.isprefix && !flags.dryrun &&
                create_parents(hdl, zc.zc_value, strlen(tosnap)) != 0) {
                  zcmd_free_nvlists(&zc);
                  return (zfs_error(hdl, EZFS_BADRESTORE, errbuf));
            }

            newfs = B_TRUE;
      }

      zc.zc_begin_record = drr_noswap->drr_u.drr_begin;
      zc.zc_cookie = infd;
      zc.zc_guid = flags.force;
      if (flags.verbose) {
            (void) printf("%s %s stream of %s into %s\n",
                flags.dryrun ? "would receive" : "receiving",
                drrb->drr_fromguid ? "incremental" : "full",
                drrb->drr_toname, zc.zc_value);
            (void) fflush(stdout);
      }

      if (flags.dryrun) {
            zcmd_free_nvlists(&zc);
            return (recv_skip(hdl, infd, flags.byteswap));
      }

      err = ioctl_err = zfs_ioctl(hdl, ZFS_IOC_RECV, &zc);
      ioctl_errno = errno;
      zcmd_free_nvlists(&zc);

      if (err == 0 && snapprops_nvlist) {
            zfs_cmd_t zc2 = { 0 };

            (void) strcpy(zc2.zc_name, zc.zc_value);
            if (zcmd_write_src_nvlist(hdl, &zc2, snapprops_nvlist) == 0) {
                  (void) zfs_ioctl(hdl, ZFS_IOC_SET_PROP, &zc2);
                  zcmd_free_nvlists(&zc2);
            }
      }

      if (err && (ioctl_errno == ENOENT || ioctl_errno == ENODEV)) {
            /*
             * It may be that this snapshot already exists,
             * in which case we want to consume & ignore it
             * rather than failing.
             */
            avl_tree_t *local_avl;
            nvlist_t *local_nv, *fs;
            char *cp = strchr(zc.zc_value, '@');

            /*
             * XXX Do this faster by just iterating over snaps in
             * this fs.  Also if zc_value does not exist, we will
             * get a strange "does not exist" error message.
             */
            *cp = '\0';
            if (gather_nvlist(hdl, zc.zc_value, NULL, NULL,
                &local_nv, &local_avl) == 0) {
                  *cp = '@';
                  fs = fsavl_find(local_avl, drrb->drr_toguid, NULL);
                  fsavl_destroy(local_avl);
                  nvlist_free(local_nv);

                  if (fs != NULL) {
                        if (flags.verbose) {
                              (void) printf("snap %s already exists; "
                                  "ignoring\n", zc.zc_value);
                        }
                        ioctl_err = recv_skip(hdl, infd,
                            flags.byteswap);
                  }
            }
            *cp = '@';
      }


      if (ioctl_err != 0) {
            switch (ioctl_errno) {
            case ENODEV:
                  cp = strchr(zc.zc_value, '@');
                  *cp = '\0';
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "most recent snapshot of %s does not\n"
                      "match incremental source"), zc.zc_value);
                  (void) zfs_error(hdl, EZFS_BADRESTORE, errbuf);
                  *cp = '@';
                  break;
            case ETXTBSY:
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "destination %s has been modified\n"
                      "since most recent snapshot"), zc.zc_name);
                  (void) zfs_error(hdl, EZFS_BADRESTORE, errbuf);
                  break;
            case EEXIST:
                  cp = strchr(zc.zc_value, '@');
                  if (newfs) {
                        /* it's the containing fs that exists */
                        *cp = '\0';
                  }
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "destination already exists"));
                  (void) zfs_error_fmt(hdl, EZFS_EXISTS,
                      dgettext(TEXT_DOMAIN, "cannot restore to %s"),
                      zc.zc_value);
                  *cp = '@';
                  break;
            case EINVAL:
                  (void) zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                  break;
            case ECKSUM:
                  zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                      "invalid stream (checksum mismatch)"));
                  (void) zfs_error(hdl, EZFS_BADSTREAM, errbuf);
                  break;
            default:
                  (void) zfs_standard_error(hdl, ioctl_errno, errbuf);
            }
      }

      /*
       * Mount or recreate the /dev links for the target filesystem
       * (if created, or if we tore them down to do an incremental
       * restore), and the /dev links for the new snapshot (if
       * created). Also mount any children of the target filesystem
       * if we did an incremental receive.
       */
      cp = strchr(zc.zc_value, '@');
      if (cp && (ioctl_err == 0 || !newfs)) {
            zfs_handle_t *h;

            *cp = '\0';
            h = zfs_open(hdl, zc.zc_value,
                ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME);
            if (h != NULL) {
                  if (h->zfs_type == ZFS_TYPE_VOLUME) {
                        *cp = '@';
                        err = zvol_create_link(hdl, h->zfs_name);
                        if (err == 0 && ioctl_err == 0)
                              err = zvol_create_link(hdl,
                                  zc.zc_value);
                  } else if (newfs) {
                        /*
                         * Track the first/top of hierarchy fs,
                         * for mounting and sharing later.
                         */
                        if (top_zfs && *top_zfs == NULL)
                              *top_zfs = zfs_strdup(hdl, zc.zc_value);
                  }
                  zfs_close(h);
            }
            *cp = '@';
      }

      if (clp) {
            err |= changelist_postfix(clp);
            changelist_free(clp);
      }

      if (err || ioctl_err)
            return (-1);

      if (flags.verbose) {
            char buf1[64];
            char buf2[64];
            uint64_t bytes = zc.zc_cookie;
            time_t delta = time(NULL) - begin_time;
            if (delta == 0)
                  delta = 1;
            zfs_nicenum(bytes, buf1, sizeof (buf1));
            zfs_nicenum(bytes/delta, buf2, sizeof (buf1));

            (void) printf("received %sB stream in %lu seconds (%sB/sec)\n",
                buf1, delta, buf2);
      }

      return (0);
}

static int
zfs_receive_impl(libzfs_handle_t *hdl, const char *tosnap, recvflags_t flags,
    int infd, avl_tree_t *stream_avl, char **top_zfs)
{
      int err;
      dmu_replay_record_t drr, drr_noswap;
      struct drr_begin *drrb = &drr.drr_u.drr_begin;
      char errbuf[1024];
      zio_cksum_t zcksum = { 0 };

      (void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
          "cannot receive"));

      if (flags.isprefix &&
          !zfs_dataset_exists(hdl, tosnap, ZFS_TYPE_DATASET)) {
            zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "specified fs "
                "(%s) does not exist"), tosnap);
            return (zfs_error(hdl, EZFS_NOENT, errbuf));
      }

      /* read in the BEGIN record */
      if (0 != (err = recv_read(hdl, infd, &drr, sizeof (drr), B_FALSE,
          &zcksum)))
            return (err);

      if (drr.drr_type == DRR_END || drr.drr_type == BSWAP_32(DRR_END)) {
            /* It's the double end record at the end of a package */
            return (ENODATA);
      }

      /* the kernel needs the non-byteswapped begin record */
      drr_noswap = drr;

      flags.byteswap = B_FALSE;
      if (drrb->drr_magic == BSWAP_64(DMU_BACKUP_MAGIC)) {
            /*
             * We computed the checksum in the wrong byteorder in
             * recv_read() above; do it again correctly.
             */
            bzero(&zcksum, sizeof (zio_cksum_t));
            fletcher_4_incremental_byteswap(&drr, sizeof (drr), &zcksum);
            flags.byteswap = B_TRUE;

            drr.drr_type = BSWAP_32(drr.drr_type);
            drr.drr_payloadlen = BSWAP_32(drr.drr_payloadlen);
            drrb->drr_magic = BSWAP_64(drrb->drr_magic);
            drrb->drr_version = BSWAP_64(drrb->drr_version);
            drrb->drr_creation_time = BSWAP_64(drrb->drr_creation_time);
            drrb->drr_type = BSWAP_32(drrb->drr_type);
            drrb->drr_flags = BSWAP_32(drrb->drr_flags);
            drrb->drr_toguid = BSWAP_64(drrb->drr_toguid);
            drrb->drr_fromguid = BSWAP_64(drrb->drr_fromguid);
      }

      if (drrb->drr_magic != DMU_BACKUP_MAGIC || drr.drr_type != DRR_BEGIN) {
            zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "invalid "
                "stream (bad magic number)"));
            return (zfs_error(hdl, EZFS_BADSTREAM, errbuf));
      }

      if (strchr(drrb->drr_toname, '@') == NULL) {
            zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "invalid "
                "stream (bad snapshot name)"));
            return (zfs_error(hdl, EZFS_BADSTREAM, errbuf));
      }

      if (drrb->drr_version == DMU_BACKUP_STREAM_VERSION) {
            return (zfs_receive_one(hdl, infd, tosnap, flags,
                &drr, &drr_noswap, stream_avl, top_zfs));
      } else if (drrb->drr_version == DMU_BACKUP_HEADER_VERSION) {
            return (zfs_receive_package(hdl, infd, tosnap, flags,
                &drr, &zcksum, top_zfs));
      } else {
            zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
                "stream is unsupported version %llu"),
                drrb->drr_version);
            return (zfs_error(hdl, EZFS_BADSTREAM, errbuf));
      }
}

/*
 * Restores a backup of tosnap from the file descriptor specified by infd.
 * Return 0 on total success, -2 if some things couldn't be
 * destroyed/renamed/promoted, -1 if some things couldn't be received.
 * (-1 will override -2).
 */
int
zfs_receive(libzfs_handle_t *hdl, const char *tosnap, recvflags_t flags,
    int infd, avl_tree_t *stream_avl)
{
      char *top_zfs = NULL;
      int err;

      err = zfs_receive_impl(hdl, tosnap, flags, infd, stream_avl, &top_zfs);

      if (err == 0 && !flags.nomount && top_zfs) {
            zfs_handle_t *zhp;
            prop_changelist_t *clp;

            zhp = zfs_open(hdl, top_zfs, ZFS_TYPE_FILESYSTEM);
            if (zhp != NULL) {
                  clp = changelist_gather(zhp, ZFS_PROP_MOUNTPOINT,
                      CL_GATHER_MOUNT_ALWAYS, 0);
                  zfs_close(zhp);
                  if (clp != NULL) {
                        /* mount and share received datasets */
                        err = changelist_postfix(clp);
                        changelist_free(clp);
                  }
            }
            if (zhp == NULL || clp == NULL || err)
                  err = -1;
      }
      if (top_zfs)
            free(top_zfs);

      return (err);
}

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