Adding upstream version 2.4.38.upstream/2.4.38upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 798 insertions, 0 deletions

diff --git a/modules/dav/main/util_lock.c b/modules/dav/main/util_lock.c
new file mode 100644
index 0000000..1b3a647
--- /dev/null
+++ b/modules/dav/main/util_lock.c
@@ -0,0 +1,798 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+** DAV repository-independent lock functions
+*/
+
+#include "apr.h"
+#include "apr_strings.h"
+
+#include "mod_dav.h"
+#include "http_log.h"
+#include "http_config.h"
+#include "http_protocol.h"
+#include "http_core.h"
+
+APLOG_USE_MODULE(dav);
+
+/* ---------------------------------------------------------------
+**
+** Property-related lock functions
+**
+*/
+
+/*
+** dav_lock_get_activelock:  Returns a <lockdiscovery> containing
+**    an activelock element for every item in the lock_discovery tree
+*/
+DAV_DECLARE(const char *) dav_lock_get_activelock(request_rec *r,
+                                                  dav_lock *lock,
+                                                  dav_buffer *pbuf)
+{
+    dav_lock *lock_scan;
+    const dav_hooks_locks *hooks = DAV_GET_HOOKS_LOCKS(r);
+    int count = 0;
+    dav_buffer work_buf = { 0 };
+    apr_pool_t *p = r->pool;
+
+    /* If no locks or no lock provider, there are no locks */
+    if (lock == NULL || hooks == NULL) {
+        /*
+        ** Since resourcediscovery is defined with (activelock)*,
+        ** <D:activelock/> shouldn't be necessary for an empty lock.
+        */
+        return "";
+    }
+
+    /*
+    ** Note: it could be interesting to sum the lengths of the owners
+    **       and locktokens during this loop. However, the buffer
+    **       mechanism provides some rough padding so that we don't
+    **       really need to have an exact size. Further, constructing
+    **       locktoken strings could be relatively expensive.
+    */
+    for (lock_scan = lock; lock_scan != NULL; lock_scan = lock_scan->next)
+        count++;
+
+    /* if a buffer was not provided, then use an internal buffer */
+    if (pbuf == NULL)
+        pbuf = &work_buf;
+
+    /* reset the length before we start appending stuff */
+    pbuf->cur_len = 0;
+
+    /* prep the buffer with a "good" size */
+    dav_check_bufsize(p, pbuf, count * 300);
+
+    for (; lock != NULL; lock = lock->next) {
+        char tmp[100];
+
+#if DAV_DEBUG
+        if (lock->rectype == DAV_LOCKREC_INDIRECT_PARTIAL) {
+            /* ### crap. design error */
+            dav_buffer_append(p, pbuf,
+                              "DESIGN ERROR: attempted to product an "
+                              "activelock element from a partial, indirect "
+                              "lock record. Creating an XML parsing error "
+                              "to ease detection of this situation: <");
+        }
+#endif
+
+        dav_buffer_append(p, pbuf, "<D:activelock>" DEBUG_CR "<D:locktype>");
+        switch (lock->type) {
+        case DAV_LOCKTYPE_WRITE:
+            dav_buffer_append(p, pbuf, "<D:write/>");
+            break;
+        default:
+            /* ### internal error. log something? */
+            break;
+        }
+        dav_buffer_append(p, pbuf, "</D:locktype>" DEBUG_CR "<D:lockscope>");
+        switch (lock->scope) {
+        case DAV_LOCKSCOPE_EXCLUSIVE:
+            dav_buffer_append(p, pbuf, "<D:exclusive/>");
+            break;
+        case DAV_LOCKSCOPE_SHARED:
+            dav_buffer_append(p, pbuf, "<D:shared/>");
+            break;
+        default:
+            /* ### internal error. log something? */
+            break;
+        }
+        dav_buffer_append(p, pbuf, "</D:lockscope>" DEBUG_CR);
+        apr_snprintf(tmp, sizeof(tmp), "<D:depth>%s</D:depth>" DEBUG_CR,
+                     lock->depth == DAV_INFINITY ? "infinity" : "0");
+        dav_buffer_append(p, pbuf, tmp);
+
+        if (lock->owner) {
+            /*
+            ** This contains a complete, self-contained <DAV:owner> element,
+            ** with namespace declarations and xml:lang handling. Just drop
+            ** it in.
+            */
+            dav_buffer_append(p, pbuf, lock->owner);
+        }
+
+        dav_buffer_append(p, pbuf, "<D:timeout>");
+        if (lock->timeout == DAV_TIMEOUT_INFINITE) {
+            dav_buffer_append(p, pbuf, "Infinite");
+        }
+        else {
+            time_t now = time(NULL);
+            
+            /*
+            ** Check if the timeout is not, for any reason, already elapsed.
+            ** (e.g., because of a large collection, or disk under heavy load...)
+             */
+            if (now >= lock->timeout) {
+                dav_buffer_append(p, pbuf, "Second-0");
+            }
+            else {
+                apr_snprintf(tmp, sizeof(tmp), "Second-%lu", (long unsigned int)(lock->timeout - now));
+                dav_buffer_append(p, pbuf, tmp);
+            }
+        }
+
+        dav_buffer_append(p, pbuf,
+                          "</D:timeout>" DEBUG_CR
+                          "<D:locktoken>" DEBUG_CR
+                          "<D:href>");
+        dav_buffer_append(p, pbuf,
+                          (*hooks->format_locktoken)(p, lock->locktoken));
+        dav_buffer_append(p, pbuf,
+                          "</D:href>" DEBUG_CR
+                          "</D:locktoken>" DEBUG_CR
+                          "</D:activelock>" DEBUG_CR);
+    }
+
+    return pbuf->buf;
+}
+
+/*
+** dav_lock_parse_lockinfo:  Validates the given xml_doc to contain a
+**    lockinfo XML element, then populates a dav_lock structure
+**    with its contents.
+*/
+DAV_DECLARE(dav_error *) dav_lock_parse_lockinfo(request_rec *r,
+                                                 const dav_resource *resource,
+                                                 dav_lockdb *lockdb,
+                                                 const apr_xml_doc *doc,
+                                                 dav_lock **lock_request)
+{
+    apr_pool_t *p = r->pool;
+    dav_error *err;
+    apr_xml_elem *child;
+    dav_lock *lock;
+
+    if (!dav_validate_root(doc, "lockinfo")) {
+        return dav_new_error(p, HTTP_BAD_REQUEST, 0, 0,
+                             "The request body contains an unexpected "
+                             "XML root element.");
+    }
+
+    if ((err = (*lockdb->hooks->create_lock)(lockdb, resource,
+                                             &lock)) != NULL) {
+        return dav_push_error(p, err->status, 0,
+                              "Could not parse the lockinfo due to an "
+                              "internal problem creating a lock structure.",
+                              err);
+    }
+
+    lock->depth = dav_get_depth(r, DAV_INFINITY);
+    if (lock->depth == -1) {
+        return dav_new_error(p, HTTP_BAD_REQUEST, 0, 0,
+                             "An invalid Depth header was specified.");
+    }
+    lock->timeout = dav_get_timeout(r);
+
+    /* Parse elements in the XML body */
+    for (child = doc->root->first_child; child; child = child->next) {
+        if (strcmp(child->name, "locktype") == 0
+            && child->first_child
+            && lock->type == DAV_LOCKTYPE_UNKNOWN) {
+            if (strcmp(child->first_child->name, "write") == 0) {
+                lock->type = DAV_LOCKTYPE_WRITE;
+                continue;
+            }
+        }
+        if (strcmp(child->name, "lockscope") == 0
+            && child->first_child
+            && lock->scope == DAV_LOCKSCOPE_UNKNOWN) {
+            if (strcmp(child->first_child->name, "exclusive") == 0)
+                lock->scope = DAV_LOCKSCOPE_EXCLUSIVE;
+            else if (strcmp(child->first_child->name, "shared") == 0)
+                lock->scope = DAV_LOCKSCOPE_SHARED;
+            if (lock->scope != DAV_LOCKSCOPE_UNKNOWN)
+                continue;
+        }
+
+        if (strcmp(child->name, "owner") == 0 && lock->owner == NULL) {
+            const char *text;
+
+            /* quote all the values in the <DAV:owner> element */
+            apr_xml_quote_elem(p, child);
+
+            /*
+            ** Store a full <DAV:owner> element with namespace definitions
+            ** and an xml:lang definition, if applicable.
+            */
+            apr_xml_to_text(p, child, APR_XML_X2T_FULL_NS_LANG, doc->namespaces,
+                            NULL, &text, NULL);
+            lock->owner = text;
+
+            continue;
+        }
+
+        return dav_new_error(p, HTTP_PRECONDITION_FAILED, 0, 0,
+                             apr_psprintf(p,
+                                         "The server cannot satisfy the "
+                                         "LOCK request due to an unknown XML "
+                                         "element (\"%s\") within the "
+                                         "DAV:lockinfo element.",
+                                         child->name));
+    }
+
+    *lock_request = lock;
+    return NULL;
+}
+
+/* ---------------------------------------------------------------
+**
+** General lock functions
+**
+*/
+
+/* dav_lock_walker:  Walker callback function to record indirect locks */
+static dav_error * dav_lock_walker(dav_walk_resource *wres, int calltype)
+{
+    dav_walker_ctx *ctx = wres->walk_ctx;
+    dav_error *err;
+
+    /* We don't want to set indirects on the target */
+    if ((*wres->resource->hooks->is_same_resource)(wres->resource,
+                                                   ctx->w.root))
+        return NULL;
+
+    if ((err = (*ctx->w.lockdb->hooks->append_locks)(ctx->w.lockdb,
+                                                     wres->resource, 1,
+                                                     ctx->lock)) != NULL) {
+        if (ap_is_HTTP_SERVER_ERROR(err->status)) {
+            /* ### add a higher-level description? */
+            return err;
+        }
+
+        /* add to the multistatus response */
+        dav_add_response(wres, err->status, NULL);
+
+        /*
+        ** ### actually, this is probably wrong: we want to fail the whole
+        ** ### LOCK process if something goes bad. maybe the caller should
+        ** ### do a dav_unlock() (e.g. a rollback) if any errors occurred.
+        */
+    }
+
+    return NULL;
+}
+
+/*
+** dav_add_lock:  Add a direct lock for resource, and indirect locks for
+**    all children, bounded by depth.
+**    ### assume request only contains one lock
+*/
+DAV_DECLARE(dav_error *) dav_add_lock(request_rec *r,
+                                      const dav_resource *resource,
+                                      dav_lockdb *lockdb, dav_lock *lock,
+                                      dav_response **response)
+{
+    dav_error *err;
+    int depth = lock->depth;
+
+    *response = NULL;
+
+    /* Requested lock can be:
+     *   Depth: 0   for null resource, existing resource, or existing collection
+     *   Depth: Inf for existing collection
+     */
+
+    /*
+    ** 2518 9.2 says to ignore depth if target is not a collection (it has
+    **   no internal children); pretend the client gave the correct depth.
+    */
+    if (!resource->collection) {
+        depth = 0;
+    }
+
+    /* In all cases, first add direct entry in lockdb */
+
+    /*
+    ** Append the new (direct) lock to the resource's existing locks.
+    **
+    ** Note: this also handles locknull resources
+    */
+    if ((err = (*lockdb->hooks->append_locks)(lockdb, resource, 0,
+                                              lock)) != NULL) {
+        /* ### maybe add a higher-level description */
+        return err;
+    }
+
+    if (depth > 0) {
+        /* Walk existing collection and set indirect locks */
+        dav_walker_ctx ctx = { { 0 } };
+        dav_response *multi_status;
+
+        ctx.w.walk_type = DAV_WALKTYPE_NORMAL | DAV_WALKTYPE_AUTH;
+        ctx.w.func = dav_lock_walker;
+        ctx.w.walk_ctx = &ctx;
+        ctx.w.pool = r->pool;
+        ctx.w.root = resource;
+        ctx.w.lockdb = lockdb;
+
+        ctx.r = r;
+        ctx.lock = lock;
+
+        err = (*resource->hooks->walk)(&ctx.w, DAV_INFINITY, &multi_status);
+        if (err != NULL) {
+            /* implies a 5xx status code occurred. screw the multistatus */
+            return err;
+        }
+
+        if (multi_status != NULL) {
+            /* manufacture a 207 error for the multistatus response */
+            *response = multi_status;
+            return dav_new_error(r->pool, HTTP_MULTI_STATUS, 0, 0,
+                                 "Error(s) occurred on resources during the "
+                                 "addition of a depth lock.");
+        }
+    }
+
+    return NULL;
+}
+
+/*
+** dav_lock_query:  Opens the lock database. Returns a linked list of
+**    dav_lock structures for all direct locks on path.
+*/
+DAV_DECLARE(dav_error*) dav_lock_query(dav_lockdb *lockdb,
+                                       const dav_resource *resource,
+                                       dav_lock **locks)
+{
+    /* If no lock database, return empty result */
+    if (lockdb == NULL) {
+        *locks = NULL;
+        return NULL;
+    }
+
+    /* ### insert a higher-level description? */
+    return (*lockdb->hooks->get_locks)(lockdb, resource,
+                                       DAV_GETLOCKS_RESOLVED,
+                                       locks);
+}
+
+/* dav_unlock_walker:  Walker callback function to remove indirect locks */
+static dav_error * dav_unlock_walker(dav_walk_resource *wres, int calltype)
+{
+    dav_walker_ctx *ctx = wres->walk_ctx;
+    dav_error *err;
+
+    /* Before removing the lock, do any auto-checkin required */
+    if (wres->resource->working) {
+        /* ### get rid of this typecast */
+        if ((err = dav_auto_checkin(ctx->r, (dav_resource *) wres->resource,
+                                    0 /*undo*/, 1 /*unlock*/, NULL))
+            != NULL) {
+            return err;
+        }
+    }
+
+    if ((err = (*ctx->w.lockdb->hooks->remove_lock)(ctx->w.lockdb,
+                                                    wres->resource,
+                                                    ctx->locktoken)) != NULL) {
+        /* ### should we stop or return a multistatus? looks like STOP */
+        /* ### add a higher-level description? */
+        return err;
+    }
+
+    return NULL;
+}
+
+/*
+** dav_get_direct_resource:
+**
+** Find a lock on the specified resource, then return the resource the
+** lock was applied to (in other words, given a (possibly) indirect lock,
+** return the direct lock's corresponding resource).
+**
+** If the lock is an indirect lock, this usually means traversing up the
+** namespace [repository] hierarchy. Note that some lock providers may be
+** able to return this information with a traversal.
+*/
+static dav_error * dav_get_direct_resource(apr_pool_t *p,
+                                           dav_lockdb *lockdb,
+                                           const dav_locktoken *locktoken,
+                                           const dav_resource *resource,
+                                           const dav_resource **direct_resource)
+{
+    if (lockdb->hooks->lookup_resource != NULL) {
+        return (*lockdb->hooks->lookup_resource)(lockdb, locktoken,
+                                                 resource, direct_resource);
+    }
+
+    *direct_resource = NULL;
+
+    /* Find the top of this lock-
+     * If r->filename's direct   locks include locktoken, use r->filename.
+     * If r->filename's indirect locks include locktoken, retry r->filename/..
+     * Else fail.
+     */
+    while (resource != NULL) {
+        dav_error *err;
+        dav_lock *lock;
+        dav_resource *parent;
+
+        /*
+        ** Find the lock specified by <locktoken> on <resource>. If it is
+        ** an indirect lock, then partial results are okay. We're just
+        ** trying to find the thing and know whether it is a direct or
+        ** an indirect lock.
+        */
+        if ((err = (*lockdb->hooks->find_lock)(lockdb, resource, locktoken,
+                                               1, &lock)) != NULL) {
+            /* ### add a higher-level desc? */
+            return err;
+        }
+
+        /* not found! that's an error. */
+        if (lock == NULL) {
+            return dav_new_error(p, HTTP_BAD_REQUEST, 0, 0,
+                                 "The specified locktoken does not correspond "
+                                 "to an existing lock on this resource.");
+        }
+
+        if (lock->rectype == DAV_LOCKREC_DIRECT) {
+            /* we found the direct lock. return this resource. */
+
+            *direct_resource = resource;
+            return NULL;
+        }
+
+        /* the lock was indirect. move up a level in the URL namespace */
+        if ((err = (*resource->hooks->get_parent_resource)(resource,
+                                                           &parent)) != NULL) {
+            /* ### add a higher-level desc? */
+            return err;
+        }
+        resource = parent;
+    }
+
+    return dav_new_error(p, HTTP_INTERNAL_SERVER_ERROR, 0, 0,
+                         "The lock database is corrupt. A direct lock could "
+                         "not be found for the corresponding indirect lock "
+                         "on this resource.");
+}
+
+/*
+** dav_unlock:  Removes all direct and indirect locks for r->filename,
+**    with given locktoken.  If locktoken == null_locktoken, all locks
+**    are removed.  If r->filename represents an indirect lock,
+**    we must unlock the appropriate direct lock.
+**    Returns OK or appropriate HTTP_* response and logs any errors.
+**
+** ### We've already crawled the tree to ensure everything was locked
+**     by us; there should be no need to incorporate a rollback.
+*/
+DAV_DECLARE(int) dav_unlock(request_rec *r, const dav_resource *resource,
+                            const dav_locktoken *locktoken)
+{
+    int result;
+    dav_lockdb *lockdb;
+    const dav_resource *lock_resource = resource;
+    const dav_hooks_locks *hooks = DAV_GET_HOOKS_LOCKS(r);
+    const dav_hooks_repository *repos_hooks = resource->hooks;
+    dav_walker_ctx ctx = { { 0 } };
+    dav_response *multi_status;
+    dav_error *err;
+
+    /* If no locks provider, then there is nothing to unlock. */
+    if (hooks == NULL) {
+        return OK;
+    }
+
+    /* 2518 requires the entire lock to be removed if resource/locktoken
+     * point to an indirect lock.  We need resource of the _direct_
+     * lock in order to walk down the tree and remove the locks.  So,
+     * If locktoken != null_locktoken,
+     *    Walk up the resource hierarchy until we see a direct lock.
+     *    Or, we could get the direct lock's db/key, pick out the URL
+     *    and do a subrequest.  I think walking up is faster and will work
+     *    all the time.
+     * Else
+     *    Just start removing all locks at and below resource.
+     */
+
+    if ((err = (*hooks->open_lockdb)(r, 0, 1, &lockdb)) != NULL) {
+        /* ### return err! maybe add a higher-level desc */
+        /* ### map result to something nice; log an error */
+        return HTTP_INTERNAL_SERVER_ERROR;
+    }
+
+    if (locktoken != NULL
+        && (err = dav_get_direct_resource(r->pool, lockdb,
+                                          locktoken, resource,
+                                          &lock_resource)) != NULL) {
+        /* ### add a higher-level desc? */
+        /* ### should return err! */
+        return err->status;
+    }
+
+    /* At this point, lock_resource/locktoken refers to a direct lock (key), ie
+     * the root of a depth > 0 lock, or locktoken is null.
+     */
+    ctx.w.walk_type = DAV_WALKTYPE_NORMAL | DAV_WALKTYPE_LOCKNULL;
+    ctx.w.func = dav_unlock_walker;
+    ctx.w.walk_ctx = &ctx;
+    ctx.w.pool = r->pool;
+    ctx.w.root = lock_resource;
+    ctx.w.lockdb = lockdb;
+
+    ctx.r = r;
+    ctx.locktoken = locktoken;
+
+    err = (*repos_hooks->walk)(&ctx.w, DAV_INFINITY, &multi_status);
+
+    /* ### fix this! */
+    /* ### do something with multi_status */
+    result = err == NULL ? OK : err->status;
+
+    (*hooks->close_lockdb)(lockdb);
+
+    return result;
+}
+
+/* dav_inherit_walker:  Walker callback function to inherit locks */
+static dav_error * dav_inherit_walker(dav_walk_resource *wres, int calltype)
+{
+    dav_walker_ctx *ctx = wres->walk_ctx;
+
+    if (ctx->skip_root
+        && (*wres->resource->hooks->is_same_resource)(wres->resource,
+                                                      ctx->w.root)) {
+        return NULL;
+    }
+
+    /* ### maybe add a higher-level desc */
+    return (*ctx->w.lockdb->hooks->append_locks)(ctx->w.lockdb,
+                                                 wres->resource, 1,
+                                                 ctx->lock);
+}
+
+/*
+** dav_inherit_locks:  When a resource or collection is added to a collection,
+**    locks on the collection should be inherited to the resource/collection.
+**    (MOVE, MKCOL, etc) Here we propagate any direct or indirect locks from
+**    parent of resource to resource and below.
+*/
+static dav_error * dav_inherit_locks(request_rec *r, dav_lockdb *lockdb,
+                                     const dav_resource *resource,
+                                     int use_parent)
+{
+    dav_error *err;
+    const dav_resource *which_resource;
+    dav_lock *locks;
+    dav_lock *scan;
+    dav_lock *prev;
+    dav_walker_ctx ctx = { { 0 } };
+    const dav_hooks_repository *repos_hooks = resource->hooks;
+    dav_response *multi_status;
+
+    if (use_parent) {
+        dav_resource *parent;
+        if ((err = (*repos_hooks->get_parent_resource)(resource,
+                                                       &parent)) != NULL) {
+            /* ### add a higher-level desc? */
+            return err;
+        }
+        if (parent == NULL) {
+            /* ### map result to something nice; log an error */
+            return dav_new_error(r->pool, HTTP_INTERNAL_SERVER_ERROR, 0, 0,
+                                 "Could not fetch parent resource. Unable to "
+                                 "inherit locks from the parent and apply "
+                                 "them to this resource.");
+        }
+        which_resource = parent;
+    }
+    else {
+        which_resource = resource;
+    }
+
+    if ((err = (*lockdb->hooks->get_locks)(lockdb, which_resource,
+                                           DAV_GETLOCKS_PARTIAL,
+                                           &locks)) != NULL) {
+        /* ### maybe add a higher-level desc */
+        return err;
+    }
+
+    if (locks == NULL) {
+        /* No locks to propagate, just return */
+        return NULL;
+    }
+
+    /*
+    ** (1) Copy all indirect locks from our parent;
+    ** (2) Create indirect locks for the depth infinity, direct locks
+    **     in our parent.
+    **
+    ** The append_locks call in the walker callback will do the indirect
+    ** conversion, but we need to remove any direct locks that are NOT
+    ** depth "infinity".
+    */
+    for (scan = locks, prev = NULL;
+         scan != NULL;
+         prev = scan, scan = scan->next) {
+
+        if (scan->rectype == DAV_LOCKREC_DIRECT
+            && scan->depth != DAV_INFINITY) {
+
+            if (prev == NULL)
+                locks = scan->next;
+            else
+                prev->next = scan->next;
+        }
+    }
+
+    /* <locks> has all our new locks.  Walk down and propagate them. */
+
+    ctx.w.walk_type = DAV_WALKTYPE_NORMAL | DAV_WALKTYPE_LOCKNULL;
+    ctx.w.func = dav_inherit_walker;
+    ctx.w.walk_ctx = &ctx;
+    ctx.w.pool = r->pool;
+    ctx.w.root = resource;
+    ctx.w.lockdb = lockdb;
+
+    ctx.r = r;
+    ctx.lock = locks;
+    ctx.skip_root = !use_parent;
+
+    /* ### do something with multi_status */
+    return (*repos_hooks->walk)(&ctx.w, DAV_INFINITY, &multi_status);
+}
+
+/* ---------------------------------------------------------------
+**
+** Functions dealing with lock-null resources
+**
+*/
+
+/*
+** dav_get_resource_state:  Returns the state of the resource
+**    r->filename:  DAV_RESOURCE_NULL, DAV_RESOURCE_LOCK_NULL,
+**    or DAV_RESOURCE_EXIST.
+**
+**    Returns DAV_RESOURCE_ERROR if an error occurs.
+*/
+DAV_DECLARE(int) dav_get_resource_state(request_rec *r,
+                                        const dav_resource *resource)
+{
+    const dav_hooks_locks *hooks = DAV_GET_HOOKS_LOCKS(r);
+
+    if (resource->exists)
+        return DAV_RESOURCE_EXISTS;
+
+    if (hooks != NULL) {
+        dav_error *err;
+        dav_lockdb *lockdb;
+        int locks_present;
+
+        /*
+        ** A locknull resource has the form:
+        **
+        **   known-dir "/" locknull-file
+        **
+        ** It would be nice to look into <resource> to verify this form,
+        ** but it does not have enough information for us. Instead, we
+        ** can look at the path_info. If the form does not match, then
+        ** there is no way we could have a locknull resource -- it must
+        ** be a plain, null resource.
+        **
+        ** Apache sets r->filename to known-dir/unknown-file and r->path_info
+        ** to "" for the "proper" case. If anything is in path_info, then
+        ** it can't be a locknull resource.
+        **
+        ** ### I bet this path_info hack doesn't work for repositories.
+        ** ### Need input from repository implementors! What kind of
+        ** ### restructure do we need? New provider APIs?
+        */
+        if (r->path_info != NULL && *r->path_info != '\0') {
+            return DAV_RESOURCE_NULL;
+        }
+
+        if ((err = (*hooks->open_lockdb)(r, 1, 1, &lockdb)) == NULL) {
+            /* note that we might see some expired locks... *shrug* */
+            err = (*hooks->has_locks)(lockdb, resource, &locks_present);
+            (*hooks->close_lockdb)(lockdb);
+        }
+
+        if (err != NULL) {
+            /* ### don't log an error. return err. add higher-level desc. */
+
+            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00623)
+                          "Failed to query lock-null status for %s",
+                          r->filename);
+
+            return DAV_RESOURCE_ERROR;
+        }
+
+        if (locks_present)
+            return DAV_RESOURCE_LOCK_NULL;
+    }
+
+    return DAV_RESOURCE_NULL;
+}
+
+DAV_DECLARE(dav_error *) dav_notify_created(request_rec *r,
+                                            dav_lockdb *lockdb,
+                                            const dav_resource *resource,
+                                            int resource_state,
+                                            int depth)
+{
+    dav_error *err;
+
+    if (resource_state == DAV_RESOURCE_LOCK_NULL) {
+
+        /*
+        ** The resource is no longer a locknull resource. This will remove
+        ** the special marker.
+        **
+        ** Note that a locknull resource has already inherited all of the
+        ** locks from the parent. We do not need to call dav_inherit_locks.
+        **
+        ** NOTE: some lock providers record locks for locknull resources using
+        **       a different key than for regular resources. this will shift
+        **       the lock information between the two key types.
+        */
+        (void)(*lockdb->hooks->remove_locknull_state)(lockdb, resource);
+
+        /*
+        ** There are resources under this one, which are new. We must
+        ** propagate the locks down to the new resources.
+        */
+        if (depth > 0 &&
+            (err = dav_inherit_locks(r, lockdb, resource, 0)) != NULL) {
+            /* ### add a higher level desc? */
+            return err;
+        }
+    }
+    else if (resource_state == DAV_RESOURCE_NULL) {
+
+        /* ### should pass depth to dav_inherit_locks so that it can
+        ** ### optimize for the depth==0 case.
+        */
+
+        /* this resource should inherit locks from its parent */
+        if ((err = dav_inherit_locks(r, lockdb, resource, 1)) != NULL) {
+
+            err = dav_push_error(r->pool, err->status, 0,
+                                 "The resource was created successfully, but "
+                                 "there was a problem inheriting locks from "
+                                 "the parent resource.",
+                                 err);
+            return err;
+        }
+    }
+    /* else the resource already exists and its locks are correct. */
+
+    return NULL;
+}