#include <stdio.h>
#include <string.h>
#include <syslog.h>

#include <slapi-plugin.h>

/* This is missing in slapi-plugin.h: */
extern int slapi_pw_find(struct berval **vals, struct berval *v);

/**
 * Private plugin data
 */

typedef struct {
   /** object type for the extension */
   int obj_type;

   /** extension handle for the extension */
   int handle;
} extension_data;

typedef struct {
   /** extension of the connection data */
   extension_data conn_ext;

   /** base DN for the service accounts */
   char *service_base_dn;

   /** id to represent the plugin for internal operations */
   Slapi_ComponentId *plugin_id;
} plugin_data;

/** Per-connection private data of this plugin. Set in pre_bind. */
typedef struct {
   /** Service name in the bind DN. */
   char *service_name;

   /**
    * If the connection was bound against a gold service (or a
    * virtual entry of a gold service).
    */
   int gold_service;
} private_connection_data;

static plugin_data private;

/** Get an entry specified by a DN and with the specified attributes.
 *
 * This functions get a entry specified by a \c DN. It's doing this with an
 * internal search and limit the requested attributes to the requested
 * values. The entry is written to an \c Slapi_Entry pointer.
 *
 * @param[in] dn \c DN of the requested entry.
 * @param[in] attrs \c NULL terminated list of requested attributes.
 * @param[out] entry Pointer to a pointer to \c Slapi_Entry to be filled with
 *                   the entry. The caller is responsible to free the filled
 *                   pointer with \c slapi_entry_free.
 * @return
 *   * 0 on success
 *   * not 0 on error (maybe an ldap errno like \c LDAP_NO_SUCH_OBJECT)
 */
static int get_entry(const char *dn, char **attrs, Slapi_Entry **entry)
{
    Slapi_Entry **entries = NULL;
    Slapi_PBlock *pb = NULL;
    int rc = 0;

    if (entry) {
        *entry = NULL;
    }

    pb = slapi_pblock_new();
    slapi_search_internal_set_pb(
        pb,
        dn,
        LDAP_SCOPE_BASE,
        "(objectclass=*)",
        attrs,
        0 /* attrsonly */,
        NULL /* controls */,
        NULL /* uniqueid */,
        private.plugin_id,
        0 /* actions */);

    slapi_search_internal_pb(pb);
    slapi_pblock_get(pb, SLAPI_PLUGIN_INTOP_RESULT, &rc);

    if (LDAP_SUCCESS == rc) {
        slapi_pblock_get(pb, SLAPI_PLUGIN_INTOP_SEARCH_ENTRIES, &entries);

        if (NULL != entries && NULL != entries[0]) {
            if (entry) {
                Slapi_Entry *tmp = NULL;
                tmp = entries[0];
                *entry = slapi_entry_dup(tmp);
            }
        } else {
            /* No entry there */
            rc = LDAP_NO_SUCH_OBJECT;
        }
    }


    slapi_free_search_results_internal(pb);
    slapi_pblock_destroy(pb);

    return rc;
}

/** Check if the given DN is a user account.
 *
 * This functions checks, if the given DN is a DN of a user account. All user
 * accounts have to have the \c splineAccount object class.
 *
 * @param[in] dn DN of the entry.
 * @param[out] gold_account If not \c NULL, this method will also check, if
 *                          the entry has the \c splineGoldAccount object
 *                          class. If the entry is a gold account this will
 *                          be set to 1, otherwise 0.
 *
 * @return 0 if the entry is a user account, 1 otherwise
 */
static int is_user(const char *dn, int *gold_account)
{
    char *attrs[] = { "objectClass", NULL };
    Slapi_Entry *entry = NULL;

    int rc = 0;

    if (gold_account != NULL) {
        *gold_account = 0;
    }

    rc |= get_entry(dn, attrs, &entry);
    if (rc != 0 || entry == NULL) {
        /* dn not found */
        rc = 1;
        goto fail1;
    }

    if (slapi_entry_attr_hasvalue(
            entry, "objectClass", "splineAccount") == 0) {
        /* no user account */
        rc = 1;
        goto fail1;
    }

    /* check if this user has a "gold" account */
    if (gold_account != NULL) {
        if (slapi_entry_attr_hasvalue(
            entry, "objectClass", "splineGoldAccount") != 0) {
            *gold_account = 1;
        }
    }

fail1:
    slapi_entry_free(entry);

    return rc;
}

/** Check if the given DN is a service account.
 *
 * This function checks, if the given DN is a DN of a service account. All
 * services have to do a bind on such a DN before a search so that this plugin
 * can identify the service and rewrite the search results to the service
 * specific password entries.
 *
 * @param[in] dn The DN to check (most times this should be the bound DN of the
 *               connection).
 * @param[out] service Pointer to a char pointer that will be filled with the
 *                     service name. The caller is responsible to free the
 *                     filled pointer with \c slapi_ch_free_string.
 *                     If this is NULL, the function will only check if the DN
 *                     is a service account and will not allocate memory for the
 *                     service name.
 * @param[out] gold_service If not \c NULL, this method will also check, if
 *                          the service requires a \c splineGoldAccount.
 * @return 0 if the entry is a service account, 1 otherwise.
 */
static int is_service(const char *dn, char **service, int *gold_service)
{
    Slapi_Entry *entry = NULL;
    char *attrs[] = { "objectClass", "cn", NULL };
    Slapi_Attr *attr = NULL;
    struct berval **cn = NULL;
    int rc = 0;

    if (gold_service != NULL) {
        *gold_service = 0;
    }

    rc |= get_entry(dn, attrs, &entry);
    if (rc != 0 || entry == NULL) {
        /* dn not found */
        rc = 1;
        goto fail1;
    }

    if (slapi_entry_attr_hasvalue(
            entry, "objectClass", "serviceAccount") == 0) {
        /* no serviceAccount */
        rc = 1;
        goto fail1;
    }

    if (gold_service != NULL) {
        if (slapi_entry_attr_hasvalue(
            entry, "objectClass", "goldServiceAccount") != 0) {
            *gold_service = 1;
        }
    }

    rc |= slapi_entry_attr_find(entry, "cn", &attr);
    if (rc != 0 || attr == NULL) {
        /* no cn attribute */
        rc = 1;
        goto fail1;
    }

    rc |= slapi_attr_get_values(attr, &cn);
    if (rc != 0 || cn == NULL) {
        /* no value in cn attribute */
        rc = 1;
        goto fail2;
    }

    if (*cn == NULL) {
        rc = 1;
        goto fail2;
    }

    if (service) {
        *service = slapi_ch_strdup((*cn)->bv_val);
    }

fail2:
    ber_bvecfree(cn);

fail1:
    slapi_entry_free(entry);

    return rc;
}

/** Try to authenticate agains a specific DN with given credentials.
 *
 * This functions simply checks if the given credentials match the saved
 * password in the \c userPassword attribute of the entry specified by the
 * given DN. This function does nothing magic and use a slapi method to
 * check the password and should support therefore all the password hashing
 * schemes supported by the slapd.
 *
 * @param[in] dn The DN of the entry.
 * @param[in] credentials A \c berval with the supplied password.
 *
 * @return
 *   * 0 is auth was successfull
 *   * -1 if the specified DN was not found
 *   * 1 in all other cases
 */
static int auth(char *dn, struct berval *credentials)
{
    char *attrs[] = { "userPassword", NULL };
    Slapi_Entry *entry = NULL;
    Slapi_Attr *attr = NULL;
    struct berval **userPasswords = NULL;

    int rc = 0;

    /* get entry */
    rc |= get_entry(dn, attrs, &entry);
    if (rc != 0 || entry == NULL) {
        rc = -1;
        goto fail1;
    }

    /* get userpassword attr */
    rc |= slapi_entry_attr_find(entry, "userPassword", &attr);
    if (rc != 0 || attr == NULL) {
        rc = 1;
        goto fail1;
    }

    /* get attribute values */
    rc |= slapi_attr_get_values(attr, &userPasswords);
    if (rc != 0 || userPasswords == NULL) {
        rc = 1;
        goto fail2;
    }

    /* check password */
    rc |= slapi_pw_find(userPasswords, credentials);

fail2:
    ber_bvecfree(userPasswords);

fail1:
    slapi_entry_free(entry);

    return rc;
}

/** Check if the supplied credentials match the stored password of a given entry
 *  or the parent entry (if the given entry does not exists).
 *
 * This function tries to check the supplied credentials against the
 * \c userPassword attribute of the entry specified by the supplied DN.
 * If the supplied DN does not exists, it will try to authenticate agains
 * the direct parent of the specified DN. If the entry exists, but does not
 * have a \c userPassword attribute or the attribute is empty, the
 * authentication will fail.
 *
 * @param[in] dn The DN of the entry.
 * @param[in] credentials A \c berval with the supplied password.
 *
 * @return
 *   * 0 if the authentication was successfull
 *   * 1 otherwise
 */
static int auth_with_password_fallback(char *dn, struct berval *credentials)
{
    char *parent_dn = NULL;

    int rc = 0;
    char fn[] = "auth_with_password_fallback in service_passwords plug-in";

    slapi_log_error(
        SLAPI_LOG_PLUGIN, fn,
        "Try password fallback with dn: %s.\n", dn);

    rc = auth(dn, credentials);
    if (rc == 0) {
        /* auth success */
        return 0;
    }
    else if (rc == 1) {
        /* auth fail, but entry exists (no fallback) */
        return 1;
    }

    /* fallback to parent dn */
    parent_dn = slapi_dn_parent(dn);
    rc = auth(parent_dn, credentials);
    slapi_ch_free_string(&parent_dn);

    if (rc == 0) {
        /* auth success */
        return 0;
    }

    return 1;
}

/** Add an attribute to an entry.
 *
 * This function adds the given attribute to the given entry. The attribute is
 * copied and merged with all values that are already available for the type
 * of the attribute.
 *
 * @param[in,out] entry Entry to be modified.
 * @param[in] attr Attribute that should be added to the entry. The attribute
 *                 values are copied to the entry.
 */
static void entry_add_attr(Slapi_Entry *entry, Slapi_Attr *attr)
{
    struct berval **vals = NULL;
    char *type = NULL;

    slapi_attr_get_type(attr, &type);
    slapi_attr_get_values(attr, &vals);
    slapi_entry_attr_merge(entry, type, vals);
    ber_bvecfree(vals);
}

/** Copy all attributes from one \c Slapi_Entry to another.
 *
 * This function iterates over all attributes in \c from and adds the attributes
 * to \c to. Attributes already contained in \c to will be preserved.
 *
 * @param[in,out] to Target for the copy operation.
 * @param[in] from Source of the attribuutes to copy.
 */
static void entry_copy_attrs(Slapi_Entry *to, Slapi_Entry *from)
{
    Slapi_Attr *attr = NULL;

    slapi_entry_first_attr(from, &attr);
    while (attr) {
        entry_add_attr(to, attr);
        slapi_entry_next_attr(from, attr, &attr);
    }
}

/** Create a copy of an \c Slapi_Entry with a new DN.
 *
 * This function creates a copy of a \c Slapi_Entry without using
 * \c slapi_entry_dup because, that would copy the two internal values for the
 * DN, that cannot be free'd with slapi_* methods. So this creates a new
 * \c Slapi_Entry, set the new DN and copies all the attributes from the old
 * entry to the newly allocated entry. The caller has to ensure, that the
   returned \c Slapi_Entry get free'd.
 *
 * @param[in] entry Source entry to create a copy from.
 * @param[in] dn The new DN of the copied entry.
 * @return The newly allocated \c Slapi_Entry.
 */
static Slapi_Entry *entry_dup_new_dn(Slapi_Entry *entry, char *dn)
{
    Slapi_Entry *new_entry = NULL;

    new_entry = slapi_entry_alloc();
    slapi_entry_set_dn(new_entry, dn);
    entry_copy_attrs(new_entry, entry);

    return new_entry;
}

/** Creates a copy of the entry and prepend the service prefix to the DN.
 *
 * This function creates a copy of the supplied entry and prepend its DN with
 * the "cn=<service>" prefix. The caller is responsible for freeing the memory
 * of the returned new \c Slapi_Entry.
 *
 * @param[in] entry The source entry for the copy with the original DN
 *                  value. All attributes will be in the newly created entry,
 *                  too.
 * @param[in] service The name of the service, that should be contained in the
 *                    prefix for the new DN. The service name should be not
 *                    longer than 251 chars (longer values will be truncated).
 * @return A new \c Slapi_Entry with the modified DN.
 */
static Slapi_Entry *prepend_service_prefix(Slapi_Entry *entry, char *service)
{
    Slapi_Entry *new_entry = NULL;
    Slapi_RDN *rdn = NULL;
    char *old_dn = NULL;
    char *new_dn = NULL;

    old_dn = slapi_entry_get_dn(entry);

    rdn = slapi_rdn_new();
    slapi_rdn_add(rdn, "cn", service);
    new_dn = slapi_dn_plus_rdn(old_dn, slapi_rdn_get_rdn(rdn));
    slapi_rdn_free(&rdn);

    new_entry = entry_dup_new_dn(entry, new_dn);
    slapi_ch_free_string(&new_dn);

    return new_entry;
}

/** The the name of the service specified by the virtual entry for a user.
 *
 * This function splits the DN in single RDN values, get the first and returns
 * the value if the type is "cn" (aka. commonName).
 *
 * @param[in] dn The dn of the virtual entry.
 * @return Pointer to the service name or NULL if the type of the first RDN is
 *         not "cn". If a pointer is returned the caller is responsible for
 *         freeing it with \c slapi_ch_free_string.
 */
static char *get_virtual_service(const char *dn)
{
    Slapi_RDN *rdn = NULL;
    char *service = NULL;
    char *type = NULL;
    char *value = NULL;

    rdn = slapi_rdn_new();
    slapi_rdn_set_dn(rdn, dn);
    slapi_rdn_get_first(rdn, &type, &value);

    if (strcmp(type, "cn") == 0) {
        service = slapi_ch_strdup(value);
    }

    slapi_rdn_free(&rdn);

    return service;
}

/** The DN of the service specified by name.
 *
 * This function builds the \c DN of a service from the service name and
 * the base dn for the services.
 *
 * @param[in] service The name of the service.
 * @return Pointer to the service dn. The caller is responsible for freeing
 *         it with \c slapi_ch_free_string.
 */
static char *get_service_dn(const char *service)
{
    char *new_dn = NULL;
    Slapi_RDN *rdn = NULL;

    rdn = slapi_rdn_new();
    slapi_rdn_add(rdn, "cn", service);
    new_dn = slapi_dn_plus_rdn(private.service_base_dn,
                               slapi_rdn_get_rdn(rdn));
    slapi_rdn_free(&rdn);

    return new_dn;
}


/** Save the information from a successful bind in the connection data.
 *
 * This method saves the verified data after a bind into the connection
 * structure. The bind dn is set as the connection dn and the service name
 * and the gold status is saved into the extension object of the connection
 * data.
 *
 * The method directly stores the pointer to the service name in the
 * extension data, so that the caller should not be free it anymore after a
 * successful call to this method. Instead the destructor of the extension
 * data (or the \c POST_UNBIND hook) will take care of the memory.
 *
 * @param[in,out] pb Parameter block of the operation.
 * @param[in] dn The bind dn.
 * @param[in] service_name The service name found in the bind dn. (The pointer
 *                         is saved inside the extensions data, so that the caller
 *                         should not free the memory.)
 * @param[in] gold_service Whether the service (found in the bind dn) is a
 *                         gold service.
 * @return
 *   * <tt>0</tt> on success
 *   * <tt>!= 0</tt> in case of any error
 */
static int save_connection_info(Slapi_PBlock *pb, char *dn, char *service_name, int gold_service)
{
    Slapi_Connection *conn;

    private_connection_data *conn_ext;

    int rc = 0;
    char fn[] = "save_connection_info in service_passwords plug-in";

    rc |= slapi_pblock_get(pb, SLAPI_CONNECTION, &conn);
    rc |= slapi_pblock_set(pb, SLAPI_CONN_DN, dn);
    if (rc != 0) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Failed to get/set connection info.\n");
        return -1;
    }

    /* set the connection private data */
    conn_ext = (private_connection_data*)slapi_get_object_extension(
        private.conn_ext.obj_type, conn, private.conn_ext.handle);
    if (conn_ext == NULL) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Failed to get connection private data.\n");
        return -1;
    }

    conn_ext->gold_service = gold_service;
    conn_ext->service_name = service_name;
    slapi_log_error(
        SLAPI_LOG_PLUGIN, fn,
        "Setting connection data: %d %s.\n",
        gold_service, service_name);

    return 0;
}

/** \c PRE_BIND plugin to allow password fallback.
 *
 * This function is called before a bind operation. If the BIND_DN is a user
 * entry with a \c cn=<service> prefix we try to authenticate against the
 * service password entry or fallback to the user entry if the serice password
 * does not exist.
 *
 * @param[in,out] pb Parameter block of the operation.
 * @return
 *   * SLAPI_BIND_SUCCESS: \b CONFUSING! This does not force the bind to
 *     succeed. This simply means to continue the processing and handle the bind
 *     in the backend.
 *   * SLAPI_BIND_FAIL: This force the bind to fail and send
 *     LDAP_INVALID_CREDENTIALS back to the client.
 *   * All other values causes special handling. If no error is set and
 *     LDAP_CONN_DN in the pb is set to a value the bind succeed. Otherwise the
 *     bind will fail. But in both cases this method is responsible for sending
 *     the response to the client.
 */
static int pre_bind(Slapi_PBlock *pb)
{
    char *dn = NULL;
    int method = 0;
    struct berval *credentials = NULL;
    int is_replication = 0;
    int is_internal = 0;

    char *parent_dn = NULL;
    char *service = NULL;
    char *service_dn = NULL;
    int gold_account = 0;
    int gold_service = 0;

    int rc = 0;
    char fn[] = "pre_bind in service_passwords plug-in";

    /* Obtain the bind information from the parameter block. */
    rc |= slapi_pblock_get(pb, SLAPI_BIND_TARGET, &dn);
    rc |= slapi_pblock_get(pb, SLAPI_BIND_METHOD, &method);
    rc |= slapi_pblock_get(pb, SLAPI_BIND_CREDENTIALS, &credentials);
    rc |= slapi_pblock_get(pb, SLAPI_IS_REPLICATED_OPERATION, &is_replication);
    rc |= slapi_pblock_get(pb, SLAPI_IS_INTERNAL_OPERATION, &is_internal);

    if (rc != 0) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Could not get parameters (error %d).\n", rc);

        /* Cancel bind */
        slapi_send_ldap_result(
            pb, LDAP_OPERATIONS_ERROR, NULL, NULL, 0, NULL);
        return LDAP_OPERATIONS_ERROR;
    }

    if (is_replication || is_internal) {
        return SLAPI_BIND_SUCCESS;
    }

    if (method != LDAP_AUTH_SIMPLE) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "The service_passwords plug-in does not handle this bind "
                "(method %d).\n",
            method);

        return SLAPI_BIND_SUCCESS;
    }

    if (is_service(dn, &service, &gold_service) != 0) {
        parent_dn = slapi_dn_parent(dn);
        rc |= is_user(parent_dn, &gold_account);
        slapi_ch_free_string(&parent_dn);

        if (rc != 0) {
            /* parent_dn is not an user, so we ignore this bind request. */
            return SLAPI_BIND_SUCCESS;
        }

        service = get_virtual_service(dn);

        service_dn = get_service_dn(service);
        rc |= is_service(service_dn, NULL, &gold_service);
        slapi_ch_free_string(&service_dn);

        if (rc != 0) {
            slapi_log_error(
                SLAPI_LOG_PLUGIN, fn,
                "Invalid service '%s' in bind dn '%s'.\n",
                service, dn);
            rc = SLAPI_BIND_FAIL;
            goto fail1;
        }

        if (gold_service != 0 && gold_account == 0) {
            /* This is a bind for a gold_service, but it's not a gold account. */
            rc = SLAPI_BIND_FAIL;
            goto fail1;
        }

        if (auth_with_password_fallback(dn, credentials) == 0) {
            /* auth success: set connection info */
            if (save_connection_info(pb, dn, service, gold_service) == 0) {
                slapi_send_ldap_result(pb, LDAP_SUCCESS, NULL, NULL, 0, NULL);
                return 1;
            }
            else {
                rc = LDAP_OPERATIONS_ERROR;
                slapi_send_ldap_result(pb, rc, NULL, NULL, 0, NULL);
                goto fail1;
            }
        }
    }
    else {
        /* service: simple auth, no fallback */
        if (auth(dn, credentials) == 0) {
            if (save_connection_info(pb, dn, service, gold_service) == 0) {
                slapi_send_ldap_result(pb, LDAP_SUCCESS, NULL, NULL, 0, NULL);
                return 1;
            }
            else {
                rc = LDAP_OPERATIONS_ERROR;
                slapi_send_ldap_result(pb, rc, NULL, NULL, 0, NULL);
                goto fail1;
            }
        }
    }

    /* wrong password */
    rc = SLAPI_BIND_FAIL;

fail1:
    slapi_ch_free_string(&service);

    /* auth fail */
    return rc;
}

/** \c POST_UNBIND plugin to reset the connection data after unbind.
 *
 * @param[in,out] pb Parameter block of the operation.
 * @return
 *   * <tt>0</tt> on success
 *   * <tt>!= 0</tt> in case of error
 */
static int post_unbind(Slapi_PBlock *pb)
{
    Slapi_Connection *conn;

    private_connection_data *conn_ext = NULL;

    int rc = 0;
    char fn[] = "post_unbind in service_passwords plug-in";

    rc |= slapi_pblock_get(pb, SLAPI_CONNECTION, &conn);

    if (rc != 0) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Could not get parameters (error %d).\n", rc);
        return rc;
    }

    conn_ext = (private_connection_data*)slapi_get_object_extension(
        private.conn_ext.obj_type, conn, private.conn_ext.handle);
    if (conn_ext == NULL) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Failed to get connection private data.\n");
        return -1;
    }

    conn_ext->gold_service = 0;

    if (conn_ext->service_name != NULL) {
        slapi_ch_free_string(&conn_ext->service_name);
        conn_ext->service_name = NULL;
    }

    return rc;
}

/** \c PRE_ENTRY plugin to rewrite returned search results to keep the service
 * name until bind.
 *
 * We want to have optional service specific password. Therefore we need to know
 * the service during bind of the user. To keep this information, we add a
 * simple (virtual) service prefix to the user DN. If a service search for
 * users, it has to do a bind with a service account before. The service name is
 * extracted from this bind and the dn of the found entries is extended to
 * \c cn=<service>,<user_dn>. During a bind the plugin can extract the service
 * name and do magic stuff.
 *
 * This function is called for each search result entry before sending it back
 * to the client and the result can be change by updating the parameter block.
 *
 * @param[in,out] pb Parameter block of the operation.
 * @return
 *   * <tt>>= 0</tt> send the result to the client and continue
 *   * <tt>< 0</tt> do not send this result, but continue with the other results
 */
static int pre_entry(Slapi_PBlock *pb)
{
    Slapi_Connection *conn;
    char *bind_dn;
    Slapi_Entry *entry;
    Slapi_Operation *op;
    int is_replication;
    int is_internal;

    private_connection_data *conn_ext = NULL;
    int gold_account = 0;
    char *parent_dn = NULL;
    const char *result_dn = NULL;
    Slapi_Entry *new_entry;

    int rc = 0;
    char fn[] = "pre_entry in service_passwords plug-in";

    rc |= slapi_pblock_get(pb, SLAPI_CONNECTION, &conn);
    rc |= slapi_pblock_get(pb, SLAPI_CONN_DN, &bind_dn);
    rc |= slapi_pblock_get(pb, SLAPI_SEARCH_RESULT_ENTRY, &entry);
    rc |= slapi_pblock_get(pb, SLAPI_OPERATION, &op);
    rc |= slapi_pblock_get(pb, SLAPI_IS_REPLICATED_OPERATION, &is_replication);
    rc |= slapi_pblock_get(pb, SLAPI_IS_INTERNAL_OPERATION, &is_internal);

    if (rc != 0) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Could not get parameters (error %d).\n",
            rc);

        slapi_send_ldap_result(
            pb, LDAP_OPERATIONS_ERROR, NULL, NULL, 0, NULL);
        return LDAP_OPERATIONS_ERROR;
    }

    if (is_replication || is_internal) {
        return 0;
    }

    if (bind_dn == NULL) {
        /* only handle authenticated searches */
        return 0;
    }

    if (slapi_op_get_type(op) != SLAPI_OPERATION_SEARCH) {
        return 0;
    }

    conn_ext = (private_connection_data*)slapi_get_object_extension(
        private.conn_ext.obj_type, conn, private.conn_ext.handle);
    if (conn_ext == NULL) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Failed to get connection private data.\n");
        return -1;
    }

    result_dn = slapi_entry_get_dn(entry);

    /* ignore service_password entries */
    parent_dn = slapi_dn_parent(result_dn);
    rc |= is_user(parent_dn, NULL);
    slapi_ch_free_string(&parent_dn);

    if (rc == 0) {
        return -1;
    }

    /* modify the dn of the returned entry */
    if (is_user(result_dn, &gold_account) == 0) {
        if (conn_ext->gold_service != 0 && gold_account == 0) {
            /* ignore non-gold account for gold services */
            return -1;
        }
        else {
            new_entry = prepend_service_prefix(entry, conn_ext->service_name);

            /* Set the new entry as the new result in the pblock and also set the
               the REP_ENTRY_MUSTBEFREED flag, so that the entry gets free'd when
               ready. */
            slapi_pblock_set(pb, SLAPI_SEARCH_RESULT_ENTRY, new_entry);
        }
    }

    return rc;
}

/** \c PRE_SEARCH plugin to rewrite the search base if it is set to the virtual
 * service entry.
 *
 * Most applications want to get the user information of a user. Some might get
 * this information by searching with the user DN as base DN. This does not work
 * for the virtual service DNs, because this entries might not exists.
 *
 * So for all searches that are executed in an authenticated connection
 * (authenticated as service account or user) the virtual prefix is dropped, if
 * the base DN is the virtual user entry. The \c PRE_ENTRY hook rewrites the
 * found user entry to the requested virtual user entry. This does nocht work,
 * if the client explicitly searches with a search filter for \c cn, but it is
 * sufficient.
 *
 * @param[in,out] pb Parameter block of the operation.
 * @return The return value do not have influence on the search operation by
 *         itself. It only stops further plugin processing (other plguins), if
 *         it is not equal 0.
 */
static int pre_search(Slapi_PBlock *pb)
{
    Slapi_Connection *conn;
    char *bind_dn;
    char *base;
    Slapi_Filter *search_filter = NULL;
    int is_replication;
    int is_internal;

    private_connection_data *conn_ext = NULL;
    char *parent_dn = NULL;
    Slapi_Filter *gold_filter = NULL;
    Slapi_Filter *joined_filter = NULL;

    int rc = 0;
    char fn[] = "pre_search in service_passwords plug-in";

    rc |= slapi_pblock_get(pb, SLAPI_CONNECTION, &conn);
    rc |= slapi_pblock_get(pb, SLAPI_CONN_DN, &bind_dn);
    rc |= slapi_pblock_get(pb, SLAPI_TARGET_DN, &base);
    rc |= slapi_pblock_get(pb, SLAPI_SEARCH_FILTER, &search_filter);
    rc |= slapi_pblock_get(pb, SLAPI_IS_REPLICATED_OPERATION, &is_replication);
    rc |= slapi_pblock_get(pb, SLAPI_IS_INTERNAL_OPERATION, &is_internal);

    if (rc != 0) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Could not get parameters (error %d).\n",
            rc);

        slapi_send_ldap_result(
            pb, LDAP_OPERATIONS_ERROR, NULL, NULL, 0, NULL);
        return LDAP_OPERATIONS_ERROR;
    }

    if (is_replication || is_internal) {
        return 0;
    }

    if (bind_dn == NULL) {
        /* only handle authenticated searches */
        return 0;
    }

    conn_ext = (private_connection_data*)slapi_get_object_extension(
        private.conn_ext.obj_type, conn, private.conn_ext.handle);
    if (conn_ext == NULL) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Failed to get connection private data.\n");
        return -1;
    }

    if (conn_ext->service_name == NULL) {
        /* ignore searches without a service in the bind_dn */
        return 0;
    }

    if (conn_ext->gold_service) {
        /* modify search filter, to only get the gold accounts */
        gold_filter = slapi_str2filter("(|(objectClass=splineGoldAccount)(!(objectClass=splineAccount)))");

        if (gold_filter == NULL) {
            slapi_log_error(
                SLAPI_LOG_PLUGIN, fn,
                "Could not build search filter\n");

            slapi_send_ldap_result(
                pb, LDAP_OPERATIONS_ERROR, NULL, NULL, 0, NULL);
            return LDAP_OPERATIONS_ERROR;
        }

        joined_filter = slapi_filter_join(LDAP_FILTER_AND, gold_filter, search_filter);

        if (joined_filter == NULL) {
            slapi_log_error(
                SLAPI_LOG_PLUGIN, fn,
                "Could not join search filters\n");

            slapi_send_ldap_result(
                pb, LDAP_OPERATIONS_ERROR, NULL, NULL, 0, NULL);
            return LDAP_OPERATIONS_ERROR;
        }

        rc |= slapi_pblock_set(pb, SLAPI_SEARCH_FILTER, joined_filter);

        if (rc != 0) {
            slapi_log_error(
                SLAPI_LOG_PLUGIN, fn,
                "Could not set new search filter (error %d).\n",
                rc);

            slapi_send_ldap_result(
                pb, LDAP_OPERATIONS_ERROR, NULL, NULL, 0, NULL);
            return LDAP_OPERATIONS_ERROR;
        }
    }

    parent_dn = slapi_dn_parent(base);

    if (is_user(parent_dn, NULL) == 0) {
        rc |= slapi_pblock_set(pb, SLAPI_TARGET_DN, parent_dn);
    }

    slapi_ch_free_string(&parent_dn);

    return rc;
}

/** Check the supplied argument list.
 *
 * The \c base_dn for service accounts is the only argument that is required.
 *
 * @param[in] pb Parameter block of the plugin initialization.
 * @return
 *   * 0 if the argument could be found
 *   * not 0 on any error
 */
static int check_arguments(Slapi_PBlock *pb)
{
    int rc = 0;

    int argc = 0;
    char **argv;

    rc |= slapi_pblock_get(pb, SLAPI_PLUGIN_ARGC, &argc);
    rc |= slapi_pblock_get(pb, SLAPI_PLUGIN_ARGV, &argv);

    if (rc != 0 || argc < 1) {
        return -1;
    }

    private.service_base_dn = slapi_ch_strdup(argv[0]);
    return 0;
}

void *create_connection_data(__attribute__((unused)) void *object,
                             __attribute__((unused)) void *parent)
{
    private_connection_data* ext;
    char fn[] = "create_connection_data in service_passwords plug-in";

    ext = (private_connection_data*)slapi_ch_malloc(sizeof(private_connection_data));
    if (ext == NULL) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Could not allocate memory.\n");
        return NULL;
    }

    ext->service_name = NULL;
    ext->gold_service = 0;
    return ext;
}

void free_connection_data(void *extension,
                          __attribute__((unused)) void *object,
                          __attribute__((unused)) void *parent)
{
    private_connection_data* ext;

    if (extension == NULL) {
        return;
    }

    ext = (private_connection_data*)extension;

    if (ext->service_name != NULL) {
        slapi_ch_free_string(&ext->service_name);
    }

    slapi_ch_free((void **)&ext);
}

Slapi_PluginDesc bindpdesc = {
    .spd_id = "service_passwords",
    .spd_vendor = "spline",
    .spd_version = "0.6",
    .spd_description = "plugin to authenticate a bind "
        "against different passwords"
};

int service_passwords_init(Slapi_PBlock *pb)
{
    int rc = 0;
    char fn[] = "service_passwords_init in service_passwords plug-in";

    rc |= check_arguments(pb);
    if (rc != 0) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Could not get arguments (error %d).\n",
            rc);
        return rc;
    }

    rc |= slapi_pblock_set(pb, SLAPI_PLUGIN_VERSION, SLAPI_PLUGIN_CURRENT_VERSION);
    rc |= slapi_pblock_set(pb, SLAPI_PLUGIN_DESCRIPTION, (void *) &bindpdesc);
    rc |= slapi_pblock_set(pb, SLAPI_PLUGIN_PRE_BIND_FN, (void *) pre_bind);
    rc |= slapi_pblock_set(pb, SLAPI_PLUGIN_PRE_ENTRY_FN, (void *) pre_entry);
    rc |= slapi_pblock_set(pb, SLAPI_PLUGIN_PRE_SEARCH_FN, (void *) pre_search);
    rc |= slapi_pblock_set(pb, SLAPI_PLUGIN_POST_UNBIND_FN, (void *) post_unbind);
    rc |= slapi_pblock_get(pb, SLAPI_PLUGIN_IDENTITY, &private.plugin_id);
    if (rc != 0) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Could not set plugin parameters (error %d).\n",
            rc);
        return rc;
    }

    rc |= slapi_register_object_extension(
        bindpdesc.spd_id, SLAPI_EXT_CONNECTION,
        create_connection_data, free_connection_data,
        &private.conn_ext.obj_type, &private.conn_ext.handle);
    if (rc != 0) {
        slapi_log_error(
            SLAPI_LOG_PLUGIN, fn,
            "Could not register connection extension (error %d).\n",
            rc);
        return rc;
    }

    return rc;
}