kadm5: Add online kadm5_iter_principals()

kadm5_get_principals() is not online.  If you have... many principals,
it will be slow.  At least it's no longer quadratic, but it, it's still
slow.  Time to add a version that uses a callback:

    kadm5_ret_t
    kadm5_iter_principals(void *server_handle,
                          const char *expression,
                          int (*cb)(void *, const char *),
                          void *cbdata)

The callback gets called with the given callback data and one principal
name (unparsed).

Note that the callback MUST NOT re-enter the kadm5 library with the
*same* kadm handle.  For example, the kadmin protocol doesn't really
multiplex requests well, though it could pipeline them, but it can't
pipeline when LIST is running, not with the protocol implemented here,
so a separate connection is needed, and that requires a separate kadm
handle.  We add kadm5_dup_context() to deal with this.

lib/kadm5/ad.c

@@ -1065,6 +1065,33 @@ kadm5_ad_get_principals(void *server_handle,
 #endif
 }
 
+static kadm5_ret_t
+kadm5_ad_iter_principals(void *server_handle,
+			 const char *expression,
+			 int (*cb)(void *, const char *),
+			 void *cbdata)
+{
+    kadm5_ad_context *context = server_handle;
+
+#ifdef OPENLDAP
+    kadm5_ret_t ret;
+
+    ret = ad_get_cred(context, NULL);
+    if (ret)
+	return ret;
+
+    ret = _kadm5_ad_connect(server_handle);
+    if (ret)
+	return ret;
+
+    krb5_set_error_message(context->context, KADM5_RPC_ERROR, "Function not implemented");
+    return KADM5_RPC_ERROR;
+#else
+    krb5_set_error_message(context->context, KADM5_RPC_ERROR, "Function not implemented");
+    return KADM5_RPC_ERROR;
+#endif
+}
+
 static kadm5_ret_t
 kadm5_ad_get_privs(void *server_handle, uint32_t*privs)
 {
@@ -1388,6 +1415,9 @@ set_funcs(kadm5_ad_context *c)
     SET(c, lock);
     SET(c, unlock);
     SETNOTIMP(c, setkey_principal_3);
+    SETNOTIMP(c, prune_principal);
+    SET(c, iter_principals);
+    SET(c, dup_context);
 }
 
 kadm5_ret_t
@@ -1455,6 +1485,12 @@ kadm5_ad_init_with_password_ctx(krb5_context context,
     return 0;
 }
 
+kadm5_ret_t
+kadm5_ad_dup_context(void *in, void **out)
+{
+    return ENOTSUP;
+}
+
 kadm5_ret_t
 kadm5_ad_init_with_password(const char *client_name,
 			    const char *password,

lib/kadm5/common_glue.c

@@ -38,6 +38,12 @@ RCSID("$Id$");
 #define __CALL(F, P) (*((kadm5_common_context*)server_handle)->funcs.F)P
 #define __CALLABLE(F) (((kadm5_common_context*)server_handle)->funcs.F != 0)
 
+kadm5_ret_t
+kadm5_dup_context(void *server_handle, void **dup_server_handle)
+{
+    return __CALL(dup_context, (server_handle, dup_server_handle));
+}
+
 kadm5_ret_t
 kadm5_chpass_principal(void *server_handle,
 		       krb5_principal princ,
@@ -222,6 +228,15 @@ kadm5_get_principals(void *server_handle,
     return __CALL(get_principals, (server_handle, expression, princs, count));
 }
 
+kadm5_ret_t
+kadm5_iter_principals(void *server_handle,
+		      const char *expression,
+                      int (*cb)(void *, const char *),
+                      void *cbdata)
+{
+    return __CALL(iter_principals, (server_handle, expression, cb, cbdata));
+}
+
 kadm5_ret_t
 kadm5_get_privs(void *server_handle,
 		uint32_t *privs)

lib/kadm5/context_s.c

@@ -112,6 +112,8 @@ set_funcs(kadm5_server_context *c)
     SET(c, lock);
     SET(c, unlock);
     SET(c, setkey_principal_3);
+    SET(c, iter_principals);
+    SET(c, dup_context);
 }
 
 #ifndef NO_UNIX_SOCKETS
@@ -250,6 +252,8 @@ _kadm5_s_init_context(kadm5_server_context **ctx,
     krb5_add_et_list (context, initialize_kadm5_error_table_r);
 
 #define is_set(M) (params && params->mask & KADM5_CONFIG_ ## M)
+    if (params)
+        (*ctx)->config.mask = params->mask;
     if (is_set(REALM)) {
 	(*ctx)->config.realm = strdup(params->realm);
         if ((*ctx)->config.realm == NULL)
@@ -275,9 +279,9 @@ _kadm5_s_init_context(kadm5_server_context **ctx,
 	    return krb5_enomem(context);
     }
 
-    find_db_spec(*ctx);
-
-    ret = _kadm5_s_init_hooks(*ctx);
+    ret = find_db_spec(*ctx);
+    if (ret == 0)
+        ret = _kadm5_s_init_hooks(*ctx);
     if (ret != 0) {
 	kadm5_s_destroy(*ctx);
 	*ctx = NULL;

lib/kadm5/destroy_s.c

@@ -42,10 +42,12 @@ RCSID("$Id$");
 static void
 destroy_config (kadm5_config_params *c)
 {
-    free (c->realm);
-    free (c->dbname);
-    free (c->acl_file);
-    free (c->stash_file);
+    if (!c)
+        return;
+    free(c->realm);
+    free(c->dbname);
+    free(c->acl_file);
+    free(c->stash_file);
 }
 
 /*
@@ -55,6 +57,8 @@ destroy_config (kadm5_config_params *c)
 static void
 destroy_kadm5_log_context (kadm5_log_context *c)
 {
+    if (!c)
+        return;
     free(c->log_file);
     if (c->socket_fd != rk_INVALID_SOCKET)
         rk_closesocket(c->socket_fd);

lib/kadm5/get_princs_c.c

@@ -66,7 +66,7 @@ kadm5_c_get_principals(void *server_handle,
     ret = krb5_store_int32(sp, kadm_get_princs);
     if (ret)
 	goto out;
-    ret = krb5_store_int32(sp, expression != NULL);
+    ret = krb5_store_int32(sp, expression != NULL ? 1 : 0);
     if (ret)
 	goto out;
     if (expression) {
@@ -117,3 +117,179 @@ kadm5_c_get_principals(void *server_handle,
     krb5_data_free(&reply);
     return ret;
 }
+
+kadm5_ret_t
+kadm5_c_iter_principals(void *server_handle,
+			const char *expression,
+			int (*cb)(void *, const char *),
+			void *cbdata)
+{
+    kadm5_client_context *context = server_handle;
+    kadm5_ret_t ret;
+    krb5_storage *sp;
+    unsigned char buf[1024];
+    int32_t tmp;
+    krb5_data reply;
+    size_t i;
+
+    ret = _kadm5_connect(server_handle, 0 /* want_write */);
+    if (ret)
+	return ret;
+
+    krb5_data_zero(&reply);
+
+    sp = krb5_storage_from_mem(buf, sizeof(buf));
+    if (sp == NULL) {
+	ret = krb5_enomem(context->context);
+	goto out_keep_error;
+    }
+    ret = krb5_store_int32(sp, kadm_get_princs);
+    if (ret)
+	goto out;
+
+    /*
+     * Our protocol has an int boolean for this operation to indicate whether
+     * there's an expression.  What we'll do here is that instead of sending
+     * just false or trueish, for online iteration we'll send a number other
+     * than 0 or 1 -- a magic value > 0 and < INT_MAX.
+     *
+     * In response we'll expect multiple replies, each with up to some small
+     * number of principal names.  See kadmin/server.c.
+     */
+    ret = krb5_store_int32(sp, 0x55555555);
+    if (ret)
+	goto out;
+    ret = krb5_store_string(sp, expression ? expression : "");
+    if (ret)
+        goto out;
+    ret = _kadm5_client_send(context, sp);
+    if (ret)
+	goto out_keep_error;
+    ret = _kadm5_client_recv(context, &reply);
+    if (ret)
+	goto out_keep_error;
+    krb5_storage_free(sp);
+    sp = krb5_storage_from_data (&reply);
+    if (sp == NULL) {
+	ret = krb5_enomem(context->context);
+	goto out_keep_error;
+    }
+    ret = krb5_ret_int32(sp, &tmp);
+    if (ret == 0)
+	ret = tmp;
+
+    if (ret)
+	goto out;
+
+    ret = krb5_ret_int32(sp, &tmp);
+    if (ret)
+	goto out;
+
+    if (tmp < 0) {
+        size_t n = -tmp;
+        int more = 1;
+        int stop = 0;
+
+        /* The server supports online iteration, hooray! */
+
+        while (more) {
+            /*
+             * We expect any number of chunks, each having `n' names, except
+             * the last one would have fewer than `n' (possibly zero, even).
+             *
+             * After that we expect one more reply with just a final return
+             * code.
+             */
+            krb5_data_free(&reply);
+            krb5_storage_free(sp);
+            sp = NULL;
+            ret = _kadm5_client_recv(context, &reply);
+            if (ret == 0 && (sp = krb5_storage_from_data(&reply)) == NULL)
+                ret = krb5_enomem(context->context);
+            if (ret)
+                goto out;
+
+            /* Every chunk begins with a status code */
+            ret = krb5_ret_int32(sp, &tmp);
+            if (ret == 0)
+                ret = tmp;
+            if (ret)
+                goto out;
+
+            /* We expect up to -tmp principals per reply */
+            for (i = 0; i < n; i++) {
+                char *princ = NULL;
+
+                ret = krb5_ret_string(sp, &princ);
+                if (ret == HEIM_ERR_EOF) {
+                    /* This was the last reply */
+                    more = 0;
+                    ret = 0;
+                    break;
+                }
+                if (ret)
+                    goto out;
+                if (!stop) {
+                    stop = cb(cbdata, princ);
+                    if (stop) {
+                        /* Tell the server to stop */
+                        krb5_storage_free(sp);
+                        if ((sp = krb5_storage_emem()) &&
+                            krb5_store_int32(sp, kadm_nop) == 0)
+                            (void) _kadm5_client_send(context, sp);
+                    }
+                }
+                free(princ);
+            }
+
+            if (!more) {
+                if (ret == 0)
+                    ret = stop;
+                break;
+            }
+        }
+        /* Get the final result code */
+        krb5_data_free(&reply);
+        krb5_storage_free(sp);
+        sp = NULL;
+        ret = _kadm5_client_recv(context, &reply);
+        if (ret == 0 && (sp = krb5_storage_from_data(&reply)) == NULL)
+            ret = krb5_enomem(context->context);
+        if (ret)
+            goto out;
+        ret = krb5_ret_int32(sp, &tmp);
+        if (ret == 0)
+            ret = tmp;
+        if (!stop) {
+            /*
+             * Send our "interrupt" after the last chunk if we hand't
+             * interrupted already.
+             */
+            krb5_storage_free(sp);
+            if ((sp = krb5_storage_emem()) &&
+                krb5_store_int32(sp, kadm_nop) == 0)
+                (void) _kadm5_client_send(context, sp);
+        }
+    } else {
+        size_t n = tmp;
+
+        /* Old server -- listing not online */
+        for (i = 0; i < n; i++) {
+            char *princ = NULL;
+
+            ret = krb5_ret_string(sp, &princ);
+            if (ret)
+                goto out;
+            cb(cbdata, princ);
+            free(princ);
+        }
+    }
+
+  out:
+    krb5_clear_error_message(context->context);
+
+  out_keep_error:
+    krb5_storage_free(sp);
+    krb5_data_free(&reply);
+    return ret;
+}

lib/kadm5/get_princs_s.c

@@ -94,7 +94,7 @@ kadm5_s_get_principals(void *server_handle,
 {
     struct foreach_data d;
     kadm5_server_context *context = server_handle;
-    kadm5_ret_t ret;
+    kadm5_ret_t ret = 0;
 
     if (!context->keep_open) {
 	ret = context->db->hdb_open(context->context, context->db, O_RDONLY, 0);
@@ -104,24 +104,25 @@ kadm5_s_get_principals(void *server_handle,
 	}
     }
     d.exp = expression;
-    {
+    d.exp2 = NULL;
+    if (expression) {
 	krb5_realm r;
 	int aret;
 
 	ret = krb5_get_default_realm(context->context, &r);
-        if (ret)
-            goto out;
-	aret = asprintf(&d.exp2, "%s@%s", expression, r);
-	free(r);
-	if (aret == -1 || d.exp2 == NULL) {
-	    ret = krb5_enomem(context->context);
-            goto out;
-	}
+        if (ret == 0) {
+            aret = asprintf(&d.exp2, "%s@%s", expression, r);
+            free(r);
+            if (aret == -1 || d.exp2 == NULL)
+                ret = krb5_enomem(context->context);
+        }
     }
     d.princs = NULL;
     d.nalloced = 0;
     d.count = 0;
-    ret = hdb_foreach(context->context, context->db, HDB_F_ADMIN_DATA, foreach, &d);
+    if (ret == 0)
+        ret = hdb_foreach(context->context, context->db, HDB_F_ADMIN_DATA,
+                          foreach, &d);
 
     if (ret == 0)
 	ret = add_princ(context->context, &d, NULL);
@@ -134,7 +135,72 @@ kadm5_s_get_principals(void *server_handle,
     else
 	kadm5_free_name_list(context, d.princs, count);
     free(d.exp2);
- out:
+    if (!context->keep_open)
+	context->db->hdb_close(context->context, context->db);
+    return _kadm5_error_code(ret);
+}
+
+struct foreach_online_data {
+    const char *exp;
+    char *exp2;
+    int (*cb)(void *, const char *);
+    void *cbdata;
+};
+
+static krb5_error_code
+foreach_online(krb5_context context, HDB *db, hdb_entry *ent, void *data)
+{
+    struct foreach_online_data *d = data;
+    krb5_error_code ret;
+    char *princ = NULL;
+
+    ret = krb5_unparse_name(context, ent->principal, &princ);
+    if (ret == 0) {
+        if (!d->exp ||
+            fnmatch(d->exp, princ, 0) == 0 || fnmatch(d->exp2, princ, 0) == 0)
+            ret = d->cb(d->cbdata, princ);
+        free(princ);
+    }
+    return ret;
+}
+
+kadm5_ret_t
+kadm5_s_iter_principals(void *server_handle,
+			const char *expression,
+			int (*cb)(void *, const char *),
+			void *cbdata)
+{
+    struct foreach_online_data d;
+    kadm5_server_context *context = server_handle;
+    kadm5_ret_t ret = 0;
+
+    if (!context->keep_open) {
+	ret = context->db->hdb_open(context->context, context->db, O_RDONLY, 0);
+	if (ret) {
+	    krb5_warn(context->context, ret, "opening database");
+	    return ret;
+	}
+    }
+    d.exp = expression;
+    d.exp2 = NULL;
+    d.cb = cb;
+    d.cbdata = cbdata;
+    if (expression) {
+	krb5_realm r;
+	int aret;
+
+	ret = krb5_get_default_realm(context->context, &r);
+        if (ret == 0) {
+            aret = asprintf(&d.exp2, "%s@%s", expression, r);
+            free(r);
+            if (aret == -1 || d.exp2 == NULL)
+                ret = krb5_enomem(context->context);
+        }
+    }
+    if (ret == 0)
+        ret = hdb_foreach(context->context, context->db, HDB_F_ADMIN_DATA,
+                          foreach_online, &d);
+    free(d.exp2);
     if (!context->keep_open)
 	context->db->hdb_close(context->context, context->db);
     return _kadm5_error_code(ret);

lib/kadm5/init_c.c

@@ -78,6 +78,8 @@ set_funcs(kadm5_client_context *c)
     SET(c, lock);
     SET(c, unlock);
     SETNOTIMP(c, setkey_principal_3);
+    SET(c, iter_principals);
+    SET(c, dup_context);
 }
 
 kadm5_ret_t
@@ -192,6 +194,53 @@ _kadm5_c_init_context(kadm5_client_context **ctx,
     return 0;
 }
 
+kadm5_ret_t
+kadm5_c_dup_context(void *vin, void **out)
+{
+    krb5_error_code ret;
+    kadm5_client_context *in = vin;
+    krb5_context context = in->context;
+    kadm5_client_context *ctx;
+
+    *out = NULL;
+    ctx = malloc(sizeof(*ctx));
+    if (ctx == NULL)
+	return krb5_enomem(in->context);
+
+
+    memset(ctx, 0, sizeof(*ctx));
+    set_funcs(ctx);
+    ctx->readonly_kadmind_port = in->readonly_kadmind_port;
+    ctx->kadmind_port = in->kadmind_port;
+
+    ret = krb5_copy_context(context, &(ctx->context));
+    if (ret == 0)
+        ret = krb5_add_et_list(ctx->context, initialize_kadm5_error_table_r);
+    if (ret == 0 && (ctx->realm = strdup(in->realm)) == NULL)
+        ret = krb5_enomem(context);
+    if (ret == 0 &&
+        (ctx->admin_server = strdup(in->admin_server)) == NULL)
+        ret = krb5_enomem(context);
+    if (in->readonly_admin_server &&
+	(ctx->readonly_admin_server = strdup(in->readonly_admin_server)) == NULL)
+        ret = krb5_enomem(context);
+    if (in->keytab && (ctx->keytab = strdup(in->keytab)) == NULL)
+        ret = krb5_enomem(context);
+    if (in->ccache) {
+        char *fullname = NULL;
+
+        ret = krb5_cc_get_full_name(context, in->ccache, &fullname);
+        if (ret == 0)
+            ret = krb5_cc_resolve(context, fullname, &ctx->ccache);
+        free(fullname);
+    }
+    if (ret == 0)
+        *out = ctx;
+    else
+        kadm5_c_destroy(ctx);
+    return ret;
+}
+
 static krb5_error_code
 get_kadm_ticket(krb5_context context,
 		krb5_ccache id,

lib/kadm5/init_s.c

@@ -108,6 +108,21 @@ kadm5_s_init_with_context(krb5_context context,
     return ret;
 }
 
+kadm5_ret_t
+kadm5_s_dup_context(void *vin, void **out)
+{
+    kadm5_server_context *in = vin;
+    kadm5_ret_t ret;
+    char *p = NULL;
+
+    ret = krb5_unparse_name(in->context, in->caller, &p);
+    if (ret == 0)
+        ret = kadm5_s_init_with_context(in->context, p, NULL,
+                                        &in->config, 0, 0, out);
+    free(p);
+    return ret;
+}
+
 kadm5_ret_t
 kadm5_s_init_with_password_ctx(krb5_context context,
 			       const char *client_name,

lib/kadm5/libkadm5srv-exports.def

@@ -15,6 +15,7 @@ EXPORTS
         kadm5_delete_policy
 	kadm5_delete_principal
 	kadm5_destroy
+	kadm5_dup_context
 	kadm5_flush
 	kadm5_free_key_data
 	kadm5_free_name_list
@@ -32,6 +33,7 @@ EXPORTS
 	kadm5_init_with_password_ctx
 	kadm5_init_with_skey
 	kadm5_init_with_skey_ctx
+	kadm5_iter_principals
         kadm5_lock
         kadm5_modify_policy
 	kadm5_modify_principal

lib/kadm5/private.h

@@ -68,6 +68,8 @@ struct kadm_func {
 				       int, krb5_key_salt_tuple *,
 				       krb5_keyblock *, int);
     kadm5_ret_t (*prune_principal) (void *, krb5_principal, int);
+    kadm5_ret_t (*iter_principals) (void*, const char*, int (*)(void *, const char *), void *);
+    kadm5_ret_t (*dup_context) (void*, void **);
 };
 
 typedef struct kadm5_hook_context {

lib/kadm5/version-script-client.map

@@ -11,6 +11,7 @@ HEIMDAL_KADM5_CLIENT_1.0 {
 		kadm5_c_create_principal;
 		kadm5_c_delete_principal;
 		kadm5_c_destroy;
+		kadm5_c_dup_context;
 		kadm5_c_flush;
 		kadm5_c_get_principal;
 		kadm5_c_get_principals;
@@ -21,6 +22,8 @@ HEIMDAL_KADM5_CLIENT_1.0 {
 		kadm5_c_init_with_password_ctx;
 		kadm5_c_init_with_skey;
 		kadm5_c_init_with_skey_ctx;
+		kadm5_c_iter_principals;
+		kadm5_c_get_privs;
 		kadm5_c_modify_principal;
 		kadm5_c_prune_principal;
 		kadm5_c_randkey_principal;
@@ -30,6 +33,7 @@ HEIMDAL_KADM5_CLIENT_1.0 {
 		kadm5_create_principal;
 		kadm5_delete_principal;
 		kadm5_destroy;
+		kadm5_dup_context;
 		kadm5_flush;
 		kadm5_free_key_data;
 		kadm5_free_name_list;
@@ -43,6 +47,7 @@ HEIMDAL_KADM5_CLIENT_1.0 {
 		kadm5_init_with_password_ctx;
 		kadm5_init_with_skey;
 		kadm5_init_with_skey_ctx;
+		kadm5_iter_principals;
 		kadm5_modify_principal;
 		kadm5_randkey_principal;
 		kadm5_randkey_principal_3;

lib/kadm5/version-script.map

@@ -16,6 +16,7 @@ HEIMDAL_KAMD5_SERVER_1.0 {
 		kadm5_create_principal_3;
 		kadm5_delete_principal;
 		kadm5_destroy;
+		kadm5_dup_context;
 		kadm5_decrypt_key;
 		kadm5_delete_policy;
 		kadm5_flush;
@@ -35,6 +36,7 @@ HEIMDAL_KAMD5_SERVER_1.0 {
 		kadm5_init_with_password_ctx;
 		kadm5_init_with_skey;
 		kadm5_init_with_skey_ctx;
+		kadm5_iter_principals;
 		kadm5_lock;
 		kadm5_modify_principal;
 		kadm5_modify_policy;