lib/unixctl.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2016 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include "unixctl.h"
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include "coverage.h"
  22 #include "dirs.h"
  23 #include "openvswitch/dynamic-string.h"
  24 #include "json.h"
  25 #include "jsonrpc.h"
  26 #include "openvswitch/list.h"
  27 #include "poll-loop.h"
  28 #include "shash.h"
  29 #include "stream.h"
  30 #include "stream-provider.h"
  31 #include "svec.h"
  32 #include "openvswitch/vlog.h"
  33
  34 VLOG_DEFINE_THIS_MODULE(unixctl);
  35
  36 COVERAGE_DEFINE(unixctl_received);
  37 COVERAGE_DEFINE(unixctl_replied);
  38 \f
  39 struct unixctl_command {
  40     const char *usage;
  41     int min_args, max_args;
  42     unixctl_cb_func *cb;
  43     void *aux;
  44 };
  45
  46 struct unixctl_conn {
  47     struct ovs_list node;
  48     struct jsonrpc *rpc;
  49
  50     /* Only one request can be in progress at a time.  While the request is
  51      * being processed, 'request_id' is populated, otherwise it is null. */
  52     struct json *request_id;   /* ID of the currently active request. */
  53 };
  54
  55 /* Server for control connection. */
  56 struct unixctl_server {
  57     struct pstream *listener;
  58     struct ovs_list conns;
  59 };
  60
  61 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
  62
  63 static struct shash commands = SHASH_INITIALIZER(&commands);
  64
  65 static void
  66 unixctl_list_commands(struct unixctl_conn *conn, int argc OVS_UNUSED,
  67                       const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
  68 {
  69     struct ds ds = DS_EMPTY_INITIALIZER;
  70     const struct shash_node **nodes = shash_sort(&commands);
  71     size_t i;
  72
  73     ds_put_cstr(&ds, "The available commands are:\n");
  74
  75     for (i = 0; i < shash_count(&commands); i++) {
  76         const struct shash_node *node = nodes[i];
  77         const struct unixctl_command *command = node->data;
  78
  79         ds_put_format(&ds, "  %-23s %s\n", node->name, command->usage);
  80     }
  81     free(nodes);
  82
  83     unixctl_command_reply(conn, ds_cstr(&ds));
  84     ds_destroy(&ds);
  85 }
  86
  87 static void
  88 unixctl_version(struct unixctl_conn *conn, int argc OVS_UNUSED,
  89                 const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
  90 {
  91     unixctl_command_reply(conn, ovs_get_program_version());
  92 }
  93
  94 /* Registers a unixctl command with the given 'name'.  'usage' describes the
  95  * arguments to the command; it is used only for presentation to the user in
  96  * "list-commands" output.
  97  *
  98  * 'cb' is called when the command is received.  It is passed an array
  99  * containing the command name and arguments, plus a copy of 'aux'.  Normally
 100  * 'cb' should reply by calling unixctl_command_reply() or
 101  * unixctl_command_reply_error() before it returns, but if the command cannot
 102  * be handled immediately then it can defer the reply until later.  A given
 103  * connection can only process a single request at a time, so a reply must be
 104  * made eventually to avoid blocking that connection. */
 105 void
 106 unixctl_command_register(const char *name, const char *usage,
 107                          int min_args, int max_args,
 108                          unixctl_cb_func *cb, void *aux)
 109 {
 110     struct unixctl_command *command;
 111     struct unixctl_command *lookup = shash_find_data(&commands, name);
 112
 113     ovs_assert(!lookup || lookup->cb == cb);
 114
 115     if (lookup) {
 116         return;
 117     }
 118
 119     command = xmalloc(sizeof *command);
 120     command->usage = usage;
 121     command->min_args = min_args;
 122     command->max_args = max_args;
 123     command->cb = cb;
 124     command->aux = aux;
 125     shash_add(&commands, name, command);
 126 }
 127
 128 static void
 129 unixctl_command_reply__(struct unixctl_conn *conn,
 130                         bool success, const char *body)
 131 {
 132     struct json *body_json;
 133     struct jsonrpc_msg *reply;
 134
 135     COVERAGE_INC(unixctl_replied);
 136     ovs_assert(conn->request_id);
 137
 138     if (!body) {
 139         body = "";
 140     }
 141
 142     if (body[0] && body[strlen(body) - 1] != '\n') {
 143         body_json = json_string_create_nocopy(xasprintf("%s\n", body));
 144     } else {
 145         body_json = json_string_create(body);
 146     }
 147
 148     if (success) {
 149         reply = jsonrpc_create_reply(body_json, conn->request_id);
 150     } else {
 151         reply = jsonrpc_create_error(body_json, conn->request_id);
 152     }
 153
 154     if (VLOG_IS_DBG_ENABLED()) {
 155         char *id = json_to_string(conn->request_id, 0);
 156         VLOG_DBG("replying with %s, id=%s: \"%s\"",
 157                  success ? "success" : "error", id, body);
 158         free(id);
 159     }
 160
 161     /* If jsonrpc_send() returns an error, the run loop will take care of the
 162      * problem eventually. */
 163     jsonrpc_send(conn->rpc, reply);
 164     json_destroy(conn->request_id);
 165     conn->request_id = NULL;
 166 }
 167
 168 /* Replies to the active unixctl connection 'conn'.  'result' is sent to the
 169  * client indicating the command was processed successfully.  Only one call to
 170  * unixctl_command_reply() or unixctl_command_reply_error() may be made per
 171  * request. */
 172 void
 173 unixctl_command_reply(struct unixctl_conn *conn, const char *result)
 174 {
 175     unixctl_command_reply__(conn, true, result);
 176 }
 177
 178 /* Replies to the active unixctl connection 'conn'. 'error' is sent to the
 179  * client indicating an error occurred processing the command.  Only one call to
 180  * unixctl_command_reply() or unixctl_command_reply_error() may be made per
 181  * request. */
 182 void
 183 unixctl_command_reply_error(struct unixctl_conn *conn, const char *error)
 184 {
 185     unixctl_command_reply__(conn, false, error);
 186 }
 187
 188 /* Creates a unixctl server listening on 'path', which for POSIX may be:
 189  *
 190  *      - NULL, in which case <rundir>/<program>.<pid>.ctl is used.
 191  *
 192  *      - A name that does not start with '/', in which case it is put in
 193  *        <rundir>.
 194  *
 195  *      - An absolute path (starting with '/') that gives the exact name of
 196  *        the Unix domain socket to listen on.
 197  *
 198  * For Windows, a kernel assigned TCP port is used and written in 'path'
 199  * which may be:
 200  *
 201  *      - NULL, in which case <rundir>/<program>.ctl is used.
 202  *
 203  *      - An absolute path that gives the name of the file.
 204  *
 205  * For both POSIX and Windows, if the path is "none", the function will
 206  * return successfully but no socket will actually be created.
 207  *
 208  * A program that (optionally) daemonizes itself should call this function
 209  * *after* daemonization, so that the socket name contains the pid of the
 210  * daemon instead of the pid of the program that exited.  (Otherwise,
 211  * "ovs-appctl --target=<program>" will fail.)
 212  *
 213  * Returns 0 if successful, otherwise a positive errno value.  If successful,
 214  * sets '*serverp' to the new unixctl_server (or to NULL if 'path' was "none"),
 215  * otherwise to NULL. */
 216 int
 217 unixctl_server_create(const char *path, struct unixctl_server **serverp)
 218 {
 219     struct unixctl_server *server;
 220     struct pstream *listener;
 221     char *punix_path;
 222     int error;
 223
 224     *serverp = NULL;
 225     if (path && !strcmp(path, "none")) {
 226         return 0;
 227     }
 228
 229     if (path) {
 230         char *abs_path;
 231 #ifndef _WIN32
 232         abs_path = abs_file_name(ovs_rundir(), path);
 233 #else
 234         abs_path = xstrdup(path);
 235 #endif
 236         punix_path = xasprintf("punix:%s", abs_path);
 237         free(abs_path);
 238     } else {
 239 #ifndef _WIN32
 240         punix_path = xasprintf("punix:%s/%s.%ld.ctl", ovs_rundir(),
 241                                program_name, (long int) getpid());
 242 #else
 243         punix_path = xasprintf("punix:%s/%s.ctl", ovs_rundir(), program_name);
 244 #endif
 245     }
 246
 247     error = pstream_open(punix_path, &listener, 0);
 248     if (error) {
 249         ovs_error(error, "could not initialize control socket %s", punix_path);
 250         goto exit;
 251     }
 252
 253     unixctl_command_register("list-commands", "", 0, 0, unixctl_list_commands,
 254                              NULL);
 255     unixctl_command_register("version", "", 0, 0, unixctl_version, NULL);
 256
 257     server = xmalloc(sizeof *server);
 258     server->listener = listener;
 259     list_init(&server->conns);
 260     *serverp = server;
 261
 262 exit:
 263     free(punix_path);
 264     return error;
 265 }
 266
 267 static void
 268 process_command(struct unixctl_conn *conn, struct jsonrpc_msg *request)
 269 {
 270     char *error = NULL;
 271
 272     struct unixctl_command *command;
 273     struct json_array *params;
 274
 275     COVERAGE_INC(unixctl_received);
 276     conn->request_id = json_clone(request->id);
 277
 278     if (VLOG_IS_DBG_ENABLED()) {
 279         char *params_s = json_to_string(request->params, 0);
 280         char *id_s = json_to_string(request->id, 0);
 281         VLOG_DBG("received request %s%s, id=%s",
 282                  request->method, params_s, id_s);
 283         free(params_s);
 284         free(id_s);
 285     }
 286
 287     params = json_array(request->params);
 288     command = shash_find_data(&commands, request->method);
 289     if (!command) {
 290         error = xasprintf("\"%s\" is not a valid command", request->method);
 291     } else if (params->n < command->min_args) {
 292         error = xasprintf("\"%s\" command requires at least %d arguments",
 293                           request->method, command->min_args);
 294     } else if (params->n > command->max_args) {
 295         error = xasprintf("\"%s\" command takes at most %d arguments",
 296                           request->method, command->max_args);
 297     } else {
 298         struct svec argv = SVEC_EMPTY_INITIALIZER;
 299         int  i;
 300
 301         svec_add(&argv, request->method);
 302         for (i = 0; i < params->n; i++) {
 303             if (params->elems[i]->type != JSON_STRING) {
 304                 error = xasprintf("\"%s\" command has non-string argument",
 305                                   request->method);
 306                 break;
 307             }
 308             svec_add(&argv, json_string(params->elems[i]));
 309         }
 310         svec_terminate(&argv);
 311
 312         if (!error) {
 313             command->cb(conn, argv.n, (const char **) argv.names,
 314                         command->aux);
 315         }
 316
 317         svec_destroy(&argv);
 318     }
 319
 320     if (error) {
 321         unixctl_command_reply_error(conn, error);
 322         free(error);
 323     }
 324 }
 325
 326 static int
 327 run_connection(struct unixctl_conn *conn)
 328 {
 329     int error, i;
 330
 331     jsonrpc_run(conn->rpc);
 332     error = jsonrpc_get_status(conn->rpc);
 333     if (error || jsonrpc_get_backlog(conn->rpc)) {
 334         return error;
 335     }
 336
 337     for (i = 0; i < 10; i++) {
 338         struct jsonrpc_msg *msg;
 339
 340         if (error || conn->request_id) {
 341             break;
 342         }
 343
 344         jsonrpc_recv(conn->rpc, &msg);
 345         if (msg) {
 346             if (msg->type == JSONRPC_REQUEST) {
 347                 process_command(conn, msg);
 348             } else {
 349                 VLOG_WARN_RL(&rl, "%s: received unexpected %s message",
 350                              jsonrpc_get_name(conn->rpc),
 351                              jsonrpc_msg_type_to_string(msg->type));
 352                 error = EINVAL;
 353             }
 354             jsonrpc_msg_destroy(msg);
 355         }
 356         error = error ? error : jsonrpc_get_status(conn->rpc);
 357     }
 358
 359     return error;
 360 }
 361
 362 static void
 363 kill_connection(struct unixctl_conn *conn)
 364 {
 365     list_remove(&conn->node);
 366     jsonrpc_close(conn->rpc);
 367     json_destroy(conn->request_id);
 368     free(conn);
 369 }
 370
 371 void
 372 unixctl_server_run(struct unixctl_server *server)
 373 {
 374     struct unixctl_conn *conn, *next;
 375     int i;
 376
 377     if (!server) {
 378         return;
 379     }
 380
 381     for (i = 0; i < 10; i++) {
 382         struct stream *stream;
 383         int error;
 384
 385         error = pstream_accept(server->listener, &stream);
 386         if (!error) {
 387             struct unixctl_conn *conn = xzalloc(sizeof *conn);
 388             list_push_back(&server->conns, &conn->node);
 389             conn->rpc = jsonrpc_open(stream);
 390         } else if (error == EAGAIN) {
 391             break;
 392         } else {
 393             VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 394                          pstream_get_name(server->listener),
 395                          ovs_strerror(error));
 396         }
 397     }
 398
 399     LIST_FOR_EACH_SAFE (conn, next, node, &server->conns) {
 400         int error = run_connection(conn);
 401         if (error && error != EAGAIN) {
 402             kill_connection(conn);
 403         }
 404     }
 405 }
 406
 407 void
 408 unixctl_server_wait(struct unixctl_server *server)
 409 {
 410     struct unixctl_conn *conn;
 411
 412     if (!server) {
 413         return;
 414     }
 415
 416     pstream_wait(server->listener);
 417     LIST_FOR_EACH (conn, node, &server->conns) {
 418         jsonrpc_wait(conn->rpc);
 419         if (!jsonrpc_get_backlog(conn->rpc)) {
 420             jsonrpc_recv_wait(conn->rpc);
 421         }
 422     }
 423 }
 424
 425 /* Destroys 'server' and stops listening for connections. */
 426 void
 427 unixctl_server_destroy(struct unixctl_server *server)
 428 {
 429     if (server) {
 430         struct unixctl_conn *conn, *next;
 431
 432         LIST_FOR_EACH_SAFE (conn, next, node, &server->conns) {
 433             kill_connection(conn);
 434         }
 435
 436         pstream_close(server->listener);
 437         free(server);
 438     }
 439 }
 440 \f
 441 /* On POSIX based systems, connects to a unixctl server socket.  'path' should
 442  * be the name of a unixctl server socket.  If it does not start with '/', it
 443  * will be prefixed with the rundir (e.g. /usr/local/var/run/openvswitch).
 444  *
 445  * On Windows, connects to a localhost TCP port as written inside 'path'.
 446  * 'path' should be an absolute path of the file.
 447  *
 448  * Returns 0 if successful, otherwise a positive errno value.  If successful,
 449  * sets '*client' to the new jsonrpc, otherwise to NULL. */
 450 int
 451 unixctl_client_create(const char *path, struct jsonrpc **client)
 452 {
 453     char *abs_path, *unix_path;
 454     struct stream *stream;
 455     int error;
 456
 457 #ifdef _WIN32
 458     abs_path = xstrdup(path);
 459 #else
 460     abs_path = abs_file_name(ovs_rundir(), path);
 461 #endif
 462     unix_path = xasprintf("unix:%s", abs_path);
 463
 464     *client = NULL;
 465
 466     error = stream_open_block(stream_open(unix_path, &stream, DSCP_DEFAULT),
 467                               &stream);
 468     free(unix_path);
 469     free(abs_path);
 470
 471     if (error) {
 472         VLOG_WARN("failed to connect to %s", path);
 473         return error;
 474     }
 475
 476     *client = jsonrpc_open(stream);
 477     return 0;
 478 }
 479
 480 /* Executes 'command' on the server with an argument vector 'argv' containing
 481  * 'argc' elements.  If successfully communicated with the server, returns 0
 482  * and sets '*result', or '*err' (not both) to the result or error the server
 483  * returned.  Otherwise, sets '*result' and '*err' to NULL and returns a
 484  * positive errno value.  The caller is responsible for freeing '*result' or
 485  * '*err' if not NULL. */
 486 int
 487 unixctl_client_transact(struct jsonrpc *client, const char *command, int argc,
 488                         char *argv[], char **result, char **err)
 489 {
 490     struct jsonrpc_msg *request, *reply;
 491     struct json **json_args, *params;
 492     int error, i;
 493
 494     *result = NULL;
 495     *err = NULL;
 496
 497     json_args = xmalloc(argc * sizeof *json_args);
 498     for (i = 0; i < argc; i++) {
 499         json_args[i] = json_string_create(argv[i]);
 500     }
 501     params = json_array_create(json_args, argc);
 502     request = jsonrpc_create_request(command, params, NULL);
 503
 504     error = jsonrpc_transact_block(client, request, &reply);
 505     if (error) {
 506         VLOG_WARN("error communicating with %s: %s", jsonrpc_get_name(client),
 507                   ovs_retval_to_string(error));
 508         return error;
 509     }
 510
 511     if (reply->error) {
 512         if (reply->error->type == JSON_STRING) {
 513             *err = xstrdup(json_string(reply->error));
 514         } else {
 515             VLOG_WARN("%s: unexpected error type in JSON RPC reply: %s",
 516                       jsonrpc_get_name(client),
 517                       json_type_to_string(reply->error->type));
 518             error = EINVAL;
 519         }
 520     } else if (reply->result) {
 521         if (reply->result->type == JSON_STRING) {
 522             *result = xstrdup(json_string(reply->result));
 523         } else {
 524             VLOG_WARN("%s: unexpected result type in JSON rpc reply: %s",
 525                       jsonrpc_get_name(client),
 526                       json_type_to_string(reply->result->type));
 527             error = EINVAL;
 528         }
 529     }
 530
 531     jsonrpc_msg_destroy(reply);
 532     return error;
 533 }