IFP: Add GetUserAttrs call

Adds a DBus method that allows the caller to retrieve attributes of a
user. The synopsis of the call is as follows:
    <method name="GetUserAttr">
        <arg type="s" name="user" direction="in"/>
        <arg type="as" name="attr" direction="in"/>
        <arg type="a{sv}" name="values" direction="out"/>
    </method>

The return value is an array (one attribute per array member) of
dictionaries. The key of the dictionary is the attribute name, the value
is a variant containing the attribute values as strings.

If an attribute does not exist or is not permitted to be read, no error
is returned. If the users does not exist, the method returns an error.

In future patches this function will be marked as obsolete in favor of
object-oriented approach.

ifp_user_get_attr_unpack_msg is a separate function to allow extending
it in a later patch.

The function to check the cache validity duplicates quite a bit of code
with the NSS responder. The refactoring would be nice to get done along
with #843.

Reviewed-by: Pavel Březina <pbrezina@redhat.com>
Reviewed-by: Stef Walter <stefw@redhat.com>

6 files changed, 597 insertions, 0 deletions

diff --git a/src/responder/ifp/ifp_iface.xml b/src/responder/ifp/ifp_iface.xml
index 078d29e2d..de6acce2f 100644
--- a/src/responder/ifp/ifp_iface.xml
+++ b/src/responder/ifp/ifp_iface.xml
@@ -3,9 +3,18 @@
 <node>
     <interface name="org.freedesktop.sssd.infopipe">
         <annotation value="infopipe_iface" name="org.freedesktop.DBus.GLib.CSymbol"/>
+
         <method name="Ping">
             <!-- manual argument parsing, raw handler -->
             <annotation name="org.freedesktop.sssd.RawHandler" value="true"/>
         </method>
+
+        <method name="GetUserAttr">
+            <arg name="user" type="s" direction="in" />
+            <arg name="attr" type="as" direction="in" />
+            <arg name="values" type="a{sv}" direction="out"/>
+            <annotation name="org.freedesktop.sssd.RawHandler" value="true"/>
+        </method>
+
     </interface>
 </node>
diff --git a/src/responder/ifp/ifp_iface_generated.c b/src/responder/ifp/ifp_iface_generated.c
index 57c67f8bc..ed8d65187 100644
--- a/src/responder/ifp/ifp_iface_generated.c
+++ b/src/responder/ifp/ifp_iface_generated.c
@@ -5,6 +5,19 @@
 #include "sbus/sssd_dbus_meta.h"
 #include "ifp_iface_generated.h"
 
+/* arguments for org.freedesktop.sssd.infopipe.GetUserAttr */
+const struct sbus_arg_meta infopipe_iface_GetUserAttr__in[] = {
+    { "user", "s" },
+    { "attr", "as" },
+    { NULL, }
+};
+
+/* arguments for org.freedesktop.sssd.infopipe.GetUserAttr */
+const struct sbus_arg_meta infopipe_iface_GetUserAttr__out[] = {
+    { "values", "a{sv}" },
+    { NULL, }
+};
+
 /* methods for org.freedesktop.sssd.infopipe */
 const struct sbus_method_meta infopipe_iface__methods[] = {
     {
@@ -14,6 +27,13 @@ const struct sbus_method_meta infopipe_iface__methods[] = {
         offsetof(struct infopipe_iface, Ping),
         NULL, /* no invoker */
     },
+    {
+        "GetUserAttr", /* name */
+        infopipe_iface_GetUserAttr__in,
+        infopipe_iface_GetUserAttr__out,
+        offsetof(struct infopipe_iface, GetUserAttr),
+        NULL, /* no invoker */
+    },
     { NULL, }
 };
 
diff --git a/src/responder/ifp/ifp_iface_generated.h b/src/responder/ifp/ifp_iface_generated.h
index f69fb162d..c52e87f06 100644
--- a/src/responder/ifp/ifp_iface_generated.h
+++ b/src/responder/ifp/ifp_iface_generated.h
@@ -14,6 +14,7 @@
 /* constants for org.freedesktop.sssd.infopipe */
 #define INFOPIPE_IFACE "org.freedesktop.sssd.infopipe"
 #define INFOPIPE_IFACE_PING "Ping"
+#define INFOPIPE_IFACE_GETUSERATTR "GetUserAttr"
 
 /* ------------------------------------------------------------------------
  * DBus handlers
@@ -37,6 +38,7 @@
 struct infopipe_iface {
     struct sbus_vtable vtable; /* derive from sbus_vtable */
     sbus_msg_handler_fn Ping;
+    sbus_msg_handler_fn GetUserAttr;
 };
 
 /* ------------------------------------------------------------------------
diff --git a/src/responder/ifp/ifp_private.h b/src/responder/ifp/ifp_private.h
index e44b27bf4..52c480bb4 100644
--- a/src/responder/ifp/ifp_private.h
+++ b/src/responder/ifp/ifp_private.h
@@ -49,6 +49,8 @@ struct ifp_ctx {
  * It will be removed later */
 int ifp_ping(struct sbus_request *dbus_req, void *data);
 
+int ifp_user_get_attr(struct sbus_request *dbus_req, void *data);
+
 /* == Utility functions == */
 struct ifp_req {
     struct sbus_request *dbus_req;
diff --git a/src/responder/ifp/ifpsrv.c b/src/responder/ifp/ifpsrv.c
index f9dc69057..978f3614a 100644
--- a/src/responder/ifp/ifpsrv.c
+++ b/src/responder/ifp/ifpsrv.c
@@ -66,6 +66,7 @@ static struct data_provider_iface ifp_dp_methods = {
 struct infopipe_iface ifp_iface = {
     { &infopipe_iface_meta, 0 },
     .Ping = ifp_ping,
+    .GetUserAttr = ifp_user_get_attr,
 };
 
 struct sss_cmd_table *get_ifp_cmds(void)
diff --git a/src/responder/ifp/ifpsrv_cmd.c b/src/responder/ifp/ifpsrv_cmd.c
index e26bcfa58..2fc4308b4 100644
--- a/src/responder/ifp/ifpsrv_cmd.c
+++ b/src/responder/ifp/ifpsrv_cmd.c
@@ -20,8 +20,571 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include "db/sysdb.h"
+
 #include "responder/ifp/ifp_private.h"
 
+struct ifp_attr_req {
+    const char *name;
+    const char **attrs;
+    int nattrs;
+
+    struct ifp_req *ireq;
+};
+
+static struct tevent_req *
+ifp_user_get_attr_send(TALLOC_CTX *mem_ctx, struct resp_ctx *rctx,
+                       struct sss_nc_ctx *ncache, int neg_timeout,
+                       const char *inp, const char **attrs);
+static errno_t ifp_user_get_attr_recv(TALLOC_CTX *mem_ctx,
+                                      struct tevent_req *req,
+                                      struct ldb_result **_res);
+
+static void ifp_user_get_attr_process(struct tevent_req *req);
+
+static errno_t
+ifp_user_get_attr_handle_reply(struct ifp_req *ireq, const char *user,
+                                const char **attrs, struct ldb_result *res);
+static errno_t
+ifp_user_get_attr_unpack_msg(struct ifp_attr_req *attr_req);
+
+int ifp_user_get_attr(struct sbus_request *dbus_req, void *data)
+{
+    errno_t ret;
+    struct ifp_req *ireq;
+    struct ifp_ctx *ifp_ctx;
+    struct ifp_attr_req *attr_req;
+    struct tevent_req *req;
+
+    ifp_ctx = talloc_get_type(data, struct ifp_ctx);
+    if (ifp_ctx == NULL) {
+        DEBUG(SSSDBG_CRIT_FAILURE, "Invalid pointer!\n");
+        return sbus_request_return_and_finish(dbus_req, DBUS_TYPE_INVALID);
+    }
+
+    ret = ifp_req_create(dbus_req, ifp_ctx, &ireq);
+    if (ret != EOK) {
+        return ifp_req_create_handle_failure(dbus_req, ret);
+    }
+
+    attr_req = talloc_zero(ireq, struct ifp_attr_req);
+    if (attr_req == NULL) {
+        return sbus_request_finish(dbus_req, NULL);
+    }
+    attr_req->ireq = ireq;
+
+    ret = ifp_user_get_attr_unpack_msg(attr_req);
+    if (ret != EOK) {
+        return ret;     /* handled internally */
+    }
+
+    DEBUG(SSSDBG_FUNC_DATA,
+          "Looking up attributes of user [%s] on behalf of %"PRIi64"\n",
+          attr_req->name, ireq->dbus_req->client);
+
+    req = ifp_user_get_attr_send(ireq, ifp_ctx->rctx,
+                                 ifp_ctx->ncache, ifp_ctx->neg_timeout,
+                                 attr_req->name, attr_req->attrs);
+    if (req == NULL) {
+        return sbus_request_finish(dbus_req, NULL);
+    }
+    tevent_req_set_callback(req, ifp_user_get_attr_process, attr_req);
+    return EOK;
+}
+
+static errno_t
+ifp_user_get_attr_unpack_msg(struct ifp_attr_req *attr_req)
+{
+    bool parsed;
+
+    parsed = sbus_request_parse_or_finish(attr_req->ireq->dbus_req,
+                                          DBUS_TYPE_STRING, &attr_req->name,
+                                          DBUS_TYPE_ARRAY, DBUS_TYPE_STRING,
+                                          &attr_req->attrs,
+                                          &attr_req->nattrs,
+                                          DBUS_TYPE_INVALID);
+    if (parsed == false) {
+        return EOK; /* handled */
+    }
+
+    return EOK;
+}
+
+static void ifp_user_get_attr_process(struct tevent_req *req)
+{
+    struct ifp_attr_req *attr_req;
+    errno_t ret;
+    struct ldb_result *res = NULL;
+
+    attr_req = tevent_req_callback_data(req, struct ifp_attr_req);
+
+    ret = ifp_user_get_attr_recv(attr_req, req, &res);
+    talloc_zfree(req);
+    if (ret == ENOENT) {
+        sbus_request_fail_and_finish(attr_req->ireq->dbus_req,
+                               sbus_error_new(attr_req->ireq->dbus_req,
+                                              DBUS_ERROR_FAILED,
+                                              "No such user\n"));
+        return;
+    } else if (ret != EOK) {
+        sbus_request_fail_and_finish(attr_req->ireq->dbus_req,
+                               sbus_error_new(attr_req->ireq->dbus_req,
+                                              DBUS_ERROR_FAILED,
+                                              "Failed to read user attribute\n"));
+        return;
+    }
+
+    ret = ifp_user_get_attr_handle_reply(attr_req->ireq, attr_req->name,
+                                         attr_req->attrs, res);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_CRIT_FAILURE, "Could not handle reply!\n");
+        /* Nothing to do, let the client time out */
+        return;
+    }
+}
+
+static errno_t
+ifp_user_get_attr_handle_reply(struct ifp_req *ireq, const char *user,
+                                const char **attrs, struct ldb_result *res)
+{
+    errno_t ret;
+    dbus_bool_t dbret;
+    DBusMessage *reply;
+    DBusMessageIter iter;
+    DBusMessageIter iter_dict;
+    struct ldb_message_element *el;
+    int ai;
+
+    /* Construct a reply */
+    reply = dbus_message_new_method_return(ireq->dbus_req->message);
+    if (!reply) {
+        return sbus_request_finish(ireq->dbus_req, NULL);
+    }
+
+    dbus_message_iter_init_append(reply, &iter);
+
+    dbret = dbus_message_iter_open_container(
+                                      &iter, DBUS_TYPE_ARRAY,
+                                      DBUS_DICT_ENTRY_BEGIN_CHAR_AS_STRING
+                                      DBUS_TYPE_STRING_AS_STRING
+                                      DBUS_TYPE_VARIANT_AS_STRING
+                                      DBUS_DICT_ENTRY_END_CHAR_AS_STRING,
+                                      &iter_dict);
+    if (!dbret) {
+        return sbus_request_finish(ireq->dbus_req, NULL);
+    }
+
+    if (res->count > 0) {
+        for (ai = 0; attrs[ai]; ai++) {
+            el = ldb_msg_find_element(res->msgs[0], attrs[ai]);
+            if (el == NULL || el->num_values == 0) {
+                DEBUG(SSSDBG_MINOR_FAILURE,
+                      "Attribute %s not present or has no values\n",
+                      attrs[ai]);
+                continue;
+            }
+
+            ret = ifp_add_ldb_el_to_dict(&iter_dict, el);
+            if (ret != EOK) {
+                DEBUG(SSSDBG_MINOR_FAILURE,
+                      "Cannot add attribute %s to message\n",
+                      attrs[ai]);
+                continue;
+            }
+        }
+    }
+
+    dbret = dbus_message_iter_close_container(&iter, &iter_dict);
+    if (!dbret) {
+        return sbus_request_finish(ireq->dbus_req, NULL);
+    }
+
+    return sbus_request_finish(ireq->dbus_req, reply);
+}
+
+struct ifp_user_get_attr_state {
+    const char *inp;
+    const char **attrs;
+    struct ldb_result *res;
+
+    char *name;
+    char *domname;
+
+    struct sss_domain_info *dom;
+    bool check_next;
+    bool check_provider;
+
+    struct resp_ctx *rctx;
+    struct sss_nc_ctx *ncache;
+    int neg_timeout;
+};
+
+static void ifp_user_get_attr_dom(struct tevent_req *subreq);
+static errno_t ifp_user_get_attr_search(struct tevent_req *req);
+int ifp_cache_check(struct ifp_user_get_attr_state *state,
+                    sss_dp_callback_t callback,
+                    unsigned int cache_refresh_percent,
+                    void *pvt);
+void ifp_user_get_attr_done(struct tevent_req *req);
+
+static struct tevent_req *
+ifp_user_get_attr_send(TALLOC_CTX *mem_ctx, struct resp_ctx *rctx,
+                       struct sss_nc_ctx *ncache, int neg_timeout,
+                       const char *inp, const char **attrs)
+{
+    errno_t ret;
+    struct tevent_req *req;
+    struct tevent_req *subreq;
+    struct ifp_user_get_attr_state *state;
+
+    req = tevent_req_create(mem_ctx, &state, struct ifp_user_get_attr_state);
+    if (req == NULL) {
+         return NULL;
+    }
+    state->inp = inp;
+    state->attrs = attrs;
+    state->rctx = rctx;
+    state->ncache = ncache;
+    state->neg_timeout = neg_timeout;
+
+    subreq = sss_parse_inp_send(req, rctx, inp);
+    if (subreq == NULL) {
+        ret = ENOMEM;
+        goto done;
+    }
+    tevent_req_set_callback(subreq, ifp_user_get_attr_dom, req);
+
+    ret = EOK;
+done:
+    if (ret != EOK) {
+        tevent_req_error(req, ret);
+    }
+    return req;
+}
+
+static void
+ifp_user_get_attr_dom(struct tevent_req *subreq)
+{
+    errno_t ret;
+    struct tevent_req *req = tevent_req_callback_data(subreq,
+                                                      struct tevent_req);
+    struct ifp_user_get_attr_state *state = tevent_req_data(req,
+                                            struct ifp_user_get_attr_state);
+
+    ret = sss_parse_inp_recv(subreq, state, &state->name, &state->domname);
+    talloc_free(subreq);
+    if (ret != EOK) {
+        tevent_req_error(req, ret);
+        return;
+    }
+
+    if (state->domname) {
+        /* this is a search in one domain */
+        state->dom = responder_get_domain(state->rctx, state->domname);
+        if (state->dom == NULL) {
+            tevent_req_error(req, EINVAL);
+            return;
+        }
+        state->check_next = false;
+    } else {
+        /* this is a multidomain search */
+        state->dom = state->rctx->domains;
+        state->check_next = true;
+    }
+
+    state->check_provider = NEED_CHECK_PROVIDER(state->dom->provider);
+
+    /* All set up, do the search! */
+    ret = ifp_user_get_attr_search(req);
+    if (ret == EOK) {
+        /* The data was cached. Just quit */
+        tevent_req_done(req);
+        return;
+    } else if (ret != EAGAIN) {
+        tevent_req_error(req, ret);
+        return;
+    }
+
+    /* Execution will resume in ifp_dp_callback */
+}
+
+static void ifp_dp_callback(uint16_t err_maj, uint32_t err_min,
+                            const char *err_msg, void *ptr);
+
+static errno_t ifp_user_get_attr_search(struct tevent_req *req)
+{
+    struct ifp_user_get_attr_state *state = tevent_req_data(req,
+                                            struct ifp_user_get_attr_state);
+    struct sss_domain_info *dom = state->dom;
+    char *name = NULL;
+    errno_t ret;
+
+    while (dom) {
+       /* if it is a domainless search, skip domains that require fully
+        * qualified names instead */
+        while (dom && state->check_next && dom->fqnames) {
+            dom = get_next_domain(dom, false);
+        }
+
+        if (!dom) break;
+
+        if (dom != state->dom) {
+            /* make sure we reset the check_provider flag when we check
+             * a new domain */
+            state->check_provider = NEED_CHECK_PROVIDER(dom->provider);
+        }
+
+        /* make sure to update the cache_req if we changed domain */
+        state->dom = dom;
+
+        talloc_free(name);
+        name = sss_get_cased_name(state, state->name, dom->case_sensitive);
+        if (!name) return ENOMEM;
+
+        /* verify this user has not yet been negatively cached,
+         * or has been permanently filtered */
+        ret = sss_ncache_check_user(state->ncache,
+                                    state->neg_timeout,
+                                    dom, name);
+        /* if neg cached, return we didn't find it */
+        if (ret == EEXIST) {
+            DEBUG(SSSDBG_TRACE_FUNC,
+                  "User [%s] does not exist in [%s]! (negative cache)\n",
+                   name, dom->name);
+            /* if a multidomain search, try with next */
+            if (state->check_next) {
+                dom = get_next_domain(dom, false);
+                continue;
+            }
+
+            /* There are no further domains or this was a
+             * fully-qualified user request.
+             */
+            return ENOENT;
+        }
+
+        DEBUG(SSSDBG_FUNC_DATA,
+              "Requesting info for [%s@%s]\n", name, dom->name);
+
+        ret = sysdb_get_user_attr(state, dom, name, state->attrs, &state->res);
+        if (ret != EOK) {
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  "Failed to make request to our cache!\n");
+            return EIO;
+        }
+
+        if (state->res->count > 1) {
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  "getpwnam call returned more than one result !?!\n");
+            return ENOENT;
+        }
+
+        if (state->res->count == 0 && state->check_provider == false) {
+            /* set negative cache only if not result of cache check */
+            ret = sss_ncache_set_user(state->ncache, false, dom, name);
+            if (ret != EOK) {
+                DEBUG(SSSDBG_MINOR_FAILURE, "Cannot set negcache for %s@%s\n",
+                      name, dom->name);
+                /* Not fatal */
+            }
+
+            /* if a multidomain search, try with next */
+            if (state->check_next) {
+                dom = get_next_domain(dom, false);
+                if (dom) continue;
+            }
+
+            DEBUG(SSSDBG_TRACE_FUNC, "No results for getpwnam call\n");
+            return ENOENT;
+        }
+
+        /* if this is a caching provider (or if we haven't checked the cache
+         * yet) then verify that the cache is uptodate */
+        if (state->check_provider) {
+            ret = ifp_cache_check(state, ifp_dp_callback, 0, req);
+            if (ret != EOK) {
+                /* Anything but EOK means we should reenter the mainloop
+                 * because we may be refreshing the cache
+                 */
+                return ret;
+            }
+        }
+
+        /* One result found */
+        DEBUG(SSSDBG_TRACE_FUNC,
+              "Returning info for user [%s@%s]\n", name, dom->name);
+        return EOK;
+    }
+
+    DEBUG(SSSDBG_MINOR_FAILURE,
+          "No matching domain found for [%s], fail!\n", state->inp);
+    return ENOENT;
+}
+
+int ifp_cache_check(struct ifp_user_get_attr_state *state,
+                    sss_dp_callback_t callback,
+                    unsigned int cache_refresh_percent,
+                    void *pvt)
+{
+    uint64_t cache_expire = 0;
+    int ret;
+    struct tevent_req *req;
+    struct dp_callback_ctx *cb_ctx = NULL;
+
+    if (state->res->count > 1) {
+        DEBUG(SSSDBG_OP_FAILURE,
+              "cache search call returned more than one result! "
+              "DB Corrupted?\n");
+        return ENOENT;
+    }
+
+    if (state->res->count > 0) {
+        cache_expire = ldb_msg_find_attr_as_uint64(state->res->msgs[0],
+                                                   SYSDB_CACHE_EXPIRE, 0);
+
+        /* if we have any reply let's check cache validity */
+        ret = sss_cmd_check_cache(state->res->msgs[0], cache_refresh_percent,
+                                cache_expire);
+        if (ret == EOK) {
+            DEBUG(SSSDBG_TRACE_FUNC, "Cached entry is valid, returning..\n");
+            return EOK;
+        } else if (ret != EAGAIN && ret != ENOENT) {
+            DEBUG(SSSDBG_CRIT_FAILURE, "Error checking cache: %d\n", ret);
+            return ret;
+        }
+    } else {
+        /* No replies */
+        ret = ENOENT;
+    }
+
+    /* EAGAIN (off band) or ENOENT (cache miss) -> check cache */
+    if (ret == EAGAIN) {
+        /* No callback required
+         * This was an out-of-band update. We'll return EOK
+         * so the calling function can return the cached entry
+         * immediately.
+         */
+        DEBUG(SSSDBG_TRACE_FUNC, "Performing midpoint cache update\n");
+
+        req = sss_dp_get_account_send(state, state->rctx, state->dom, true,
+                                      SSS_DP_USER, state->inp, 0,
+                                      NULL);
+        if (req == NULL) {
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  "Out of memory sending out-of-band data provider "
+                  "request\n");
+            /* This is non-fatal, so we'll continue here */
+        } else {
+            DEBUG(SSSDBG_TRACE_FUNC, "Updating cache out-of-band\n");
+        }
+
+        /* We don't need to listen for a reply, so we will free the
+         * request here.
+         */
+        talloc_zfree(req);
+    } else {
+        /* This is a cache miss. Or the cache is expired.
+         * We need to get the updated user information before returning it.
+         */
+
+        /* dont loop forever; mark the provider as checked */
+        state->check_provider = false;
+
+        req = sss_dp_get_account_send(state, state->rctx, state->dom, true,
+                                      SSS_DP_USER, state->inp, 0, NULL);
+        if (req == NULL) {
+            DEBUG(SSSDBG_CRIT_FAILURE,
+                  "Out of memory sending data provider request\n");
+            return ENOMEM;
+        }
+
+        cb_ctx = talloc_zero(state, struct dp_callback_ctx);
+        if (cb_ctx == NULL) {
+            talloc_zfree(req);
+            return ENOMEM;
+        }
+        cb_ctx->callback = callback;
+        cb_ctx->ptr = pvt;
+        cb_ctx->cctx = NULL;   /* There is no client in ifp */
+        cb_ctx->mem_ctx = state;
+
+        tevent_req_set_callback(req, ifp_user_get_attr_done, cb_ctx);
+        return EAGAIN;
+    }
+
+    return EOK;
+}
+
+void ifp_user_get_attr_done(struct tevent_req *req)
+{
+    struct dp_callback_ctx *cb_ctx =
+        tevent_req_callback_data(req, struct dp_callback_ctx);
+
+    errno_t ret;
+    dbus_uint16_t err_maj;
+    dbus_uint32_t err_min;
+    char *err_msg;
+
+    ret = sss_dp_get_account_recv(cb_ctx->mem_ctx, req,
+                                  &err_maj, &err_min,
+                                  &err_msg);
+    talloc_zfree(req);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_OP_FAILURE, "Could not get account info: %d\n", ret);
+        /* report error with callback */
+    }
+
+    cb_ctx->callback(err_maj, err_min, err_msg, cb_ctx->ptr);
+}
+
+static void ifp_dp_callback(uint16_t err_maj, uint32_t err_min,
+                            const char *err_msg, void *ptr)
+{
+    errno_t ret;
+    struct tevent_req *req = talloc_get_type(ptr, struct tevent_req);
+
+    if (err_maj) {
+        DEBUG(SSSDBG_MINOR_FAILURE,
+              "Unable to get information from Data Provider\n"
+              "Error: %u, %u, %s\n"
+              "Will try to return what we have in cache\n",
+              (unsigned int)err_maj, (unsigned int)err_min, err_msg);
+    }
+
+    /* Backend was updated successfully. Check again */
+    ret = ifp_user_get_attr_search(req);
+    if (ret == EAGAIN) {
+        /* Another search in progress */
+        return;
+    } else if (ret != EOK) {
+        tevent_req_error(req, ret);
+        return;
+    }
+
+    tevent_req_done(req);
+}
+
+static errno_t
+ifp_user_get_attr_recv(TALLOC_CTX *mem_ctx,
+                       struct tevent_req *req,
+                       struct ldb_result **_res)
+{
+    struct ifp_user_get_attr_state *state = tevent_req_data(req,
+                                            struct ifp_user_get_attr_state);
+
+    TEVENT_REQ_RETURN_ON_ERROR(req);
+
+    if (state->res == NULL) {
+        /* Did the request end with success but with no data? */
+        return ENOENT;
+    }
+
+    if (_res) {
+        *_res = talloc_steal(mem_ctx, state->res);
+    }
+    return EOK;
+}
+
 struct cli_protocol_version *register_cli_protocol_version(void)
 {
     static struct cli_protocol_version ssh_cli_protocol_version[] = {