lib/unixctl.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira Networks.
   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 <assert.h>
  20 #include <errno.h>
  21 #include <unistd.h>
  22 #include "coverage.h"
  23 #include "dirs.h"
  24 #include "dynamic-string.h"
  25 #include "json.h"
  26 #include "jsonrpc.h"
  27 #include "list.h"
  28 #include "poll-loop.h"
  29 #include "shash.h"
  30 #include "stream.h"
  31 #include "svec.h"
  32 #include "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 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 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_help(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, 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  * "help" output.
  97  *
  98  * 'cb' is called when the command is received.  It is passed the actual set of
  99  * arguments, as a text string, plus a copy of 'aux'.  Normally 'cb' should
 100  * reply by calling unixctl_command_reply() or unixctl_command_reply_error()
 101  * before it returns, but if the command cannot be handled immediately then it
 102  * can defer the reply until later.  A given connection can only process a
 103  * single request at a time, so a reply must be made eventually to avoid
 104  * 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     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     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 jsonrpc_send() returns an error, the run loop will take care of the
 155      * problem eventually. */
 156     jsonrpc_send(conn->rpc, reply);
 157     json_destroy(conn->request_id);
 158     conn->request_id = NULL;
 159 }
 160
 161 /* Replies to the active unixctl connection 'conn'.  'result' is sent to the
 162  * client indicating the command was processed successfully.  Only one call to
 163  * unixctl_command_reply() or unixctl_command_reply_error() may be made per
 164  * request. */
 165 void
 166 unixctl_command_reply(struct unixctl_conn *conn, const char *result)
 167 {
 168     unixctl_command_reply__(conn, true, result);
 169 }
 170
 171 /* Replies to the active unixctl connection 'conn'. 'error' is sent to the
 172  * client indicating an error occured processing the command.  Only one call to
 173  * unixctl_command_reply() or unixctl_command_reply_error() may be made per
 174  * request. */
 175 void
 176 unixctl_command_reply_error(struct unixctl_conn *conn, const char *error)
 177 {
 178     unixctl_command_reply__(conn, false, error);
 179 }
 180
 181 /* Creates a unixctl server listening on 'path', which may be:
 182  *
 183  *      - NULL, in which case <rundir>/<program>.<pid>.ctl is used.
 184  *
 185  *      - "none", in which case the function will return successfully but
 186  *        no socket will actually be created.
 187  *
 188  *      - A name that does not start with '/', in which case it is put in
 189  *        <rundir>.
 190  *
 191  *      - An absolute path (starting with '/') that gives the exact name of
 192  *        the Unix domain socket to listen on.
 193  *
 194  * A program that (optionally) daemonizes itself should call this function
 195  * *after* daemonization, so that the socket name contains the pid of the
 196  * daemon instead of the pid of the program that exited.  (Otherwise,
 197  * "ovs-appctl --target=<program>" will fail.)
 198  *
 199  * Returns 0 if successful, otherwise a positive errno value.  If successful,
 200  * sets '*serverp' to the new unixctl_server (or to NULL if 'path' was "none"),
 201  * otherwise to NULL. */
 202 int
 203 unixctl_server_create(const char *path, struct unixctl_server **serverp)
 204 {
 205     struct unixctl_server *server;
 206     struct pstream *listener;
 207     char *punix_path;
 208     int error;
 209
 210     *serverp = NULL;
 211     if (path && !strcmp(path, "none")) {
 212         return 0;
 213     }
 214
 215     if (path) {
 216         char *abs_path = abs_file_name(ovs_rundir(), path);
 217         punix_path = xasprintf("punix:%s", abs_path);
 218         free(abs_path);
 219     } else {
 220         punix_path = xasprintf("punix:%s/%s.%ld.ctl", ovs_rundir(),
 221                                program_name, (long int) getpid());
 222     }
 223
 224     error = pstream_open(punix_path, &listener, DSCP_INVALID);
 225     if (error) {
 226         ovs_error(error, "could not initialize control socket %s", punix_path);
 227         goto exit;
 228     }
 229
 230     unixctl_command_register("help", "", 0, 0, unixctl_help, NULL);
 231     unixctl_command_register("version", "", 0, 0, unixctl_version, NULL);
 232
 233     server = xmalloc(sizeof *server);
 234     server->listener = listener;
 235     list_init(&server->conns);
 236     *serverp = server;
 237
 238 exit:
 239     free(punix_path);
 240     return error;
 241 }
 242
 243 static void
 244 process_command(struct unixctl_conn *conn, struct jsonrpc_msg *request)
 245 {
 246     char *error = NULL;
 247
 248     struct unixctl_command *command;
 249     struct json_array *params;
 250
 251     COVERAGE_INC(unixctl_received);
 252     conn->request_id = json_clone(request->id);
 253
 254     params = json_array(request->params);
 255     command = shash_find_data(&commands, request->method);
 256     if (!command) {
 257         error = xasprintf("\"%s\" is not a valid command", request->method);
 258     } else if (params->n < command->min_args) {
 259         error = xasprintf("\"%s\" command requires at least %d arguments",
 260                           request->method, command->min_args);
 261     } else if (params->n > command->max_args) {
 262         error = xasprintf("\"%s\" command takes at most %d arguments",
 263                           request->method, command->max_args);
 264     } else {
 265         struct svec argv = SVEC_EMPTY_INITIALIZER;
 266         int  i;
 267
 268         svec_add(&argv, request->method);
 269         for (i = 0; i < params->n; i++) {
 270             if (params->elems[i]->type != JSON_STRING) {
 271                 error = xasprintf("\"%s\" command has non-string argument",
 272                                   request->method);
 273                 break;
 274             }
 275             svec_add(&argv, json_string(params->elems[i]));
 276         }
 277         svec_terminate(&argv);
 278
 279         if (!error) {
 280             command->cb(conn, argv.n, (const char **) argv.names,
 281                         command->aux);
 282         }
 283
 284         svec_destroy(&argv);
 285     }
 286
 287     if (error) {
 288         unixctl_command_reply_error(conn, error);
 289         free(error);
 290     }
 291 }
 292
 293 static int
 294 run_connection(struct unixctl_conn *conn)
 295 {
 296     int error, i;
 297
 298     jsonrpc_run(conn->rpc);
 299     error = jsonrpc_get_status(conn->rpc);
 300     if (error || jsonrpc_get_backlog(conn->rpc)) {
 301         return error;
 302     }
 303
 304     for (i = 0; i < 10; i++) {
 305         struct jsonrpc_msg *msg;
 306
 307         if (error || conn->request_id) {
 308             break;
 309         }
 310
 311         jsonrpc_recv(conn->rpc, &msg);
 312         if (msg) {
 313             if (msg->type == JSONRPC_REQUEST) {
 314                 process_command(conn, msg);
 315             } else {
 316                 VLOG_WARN_RL(&rl, "%s: received unexpected %s message",
 317                              jsonrpc_get_name(conn->rpc),
 318                              jsonrpc_msg_type_to_string(msg->type));
 319                 error = EINVAL;
 320             }
 321             jsonrpc_msg_destroy(msg);
 322         }
 323         error = error ? error : jsonrpc_get_status(conn->rpc);
 324     }
 325
 326     return error;
 327 }
 328
 329 static void
 330 kill_connection(struct unixctl_conn *conn)
 331 {
 332     list_remove(&conn->node);
 333     jsonrpc_close(conn->rpc);
 334     json_destroy(conn->request_id);
 335     free(conn);
 336 }
 337
 338 void
 339 unixctl_server_run(struct unixctl_server *server)
 340 {
 341     struct unixctl_conn *conn, *next;
 342     int i;
 343
 344     if (!server) {
 345         return;
 346     }
 347
 348     for (i = 0; i < 10; i++) {
 349         struct stream *stream;
 350         int error;
 351
 352         error = pstream_accept(server->listener, &stream);
 353         if (!error) {
 354             struct unixctl_conn *conn = xzalloc(sizeof *conn);
 355             list_push_back(&server->conns, &conn->node);
 356             conn->rpc = jsonrpc_open(stream);
 357         } else if (error == EAGAIN) {
 358             break;
 359         } else {
 360             VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 361                          pstream_get_name(server->listener),
 362                          strerror(error));
 363         }
 364     }
 365
 366     LIST_FOR_EACH_SAFE (conn, next, node, &server->conns) {
 367         int error = run_connection(conn);
 368         if (error && error != EAGAIN) {
 369             kill_connection(conn);
 370         }
 371     }
 372 }
 373
 374 void
 375 unixctl_server_wait(struct unixctl_server *server)
 376 {
 377     struct unixctl_conn *conn;
 378
 379     if (!server) {
 380         return;
 381     }
 382
 383     pstream_wait(server->listener);
 384     LIST_FOR_EACH (conn, node, &server->conns) {
 385         jsonrpc_wait(conn->rpc);
 386         if (!jsonrpc_get_backlog(conn->rpc)) {
 387             jsonrpc_recv_wait(conn->rpc);
 388         }
 389     }
 390 }
 391
 392 /* Destroys 'server' and stops listening for connections. */
 393 void
 394 unixctl_server_destroy(struct unixctl_server *server)
 395 {
 396     if (server) {
 397         struct unixctl_conn *conn, *next;
 398
 399         LIST_FOR_EACH_SAFE (conn, next, node, &server->conns) {
 400             kill_connection(conn);
 401         }
 402
 403         pstream_close(server->listener);
 404         free(server);
 405     }
 406 }
 407 \f
 408 /* Connects to a unixctl server socket.  'path' should be the name of a unixctl
 409  * server socket.  If it does not start with '/', it will be prefixed with the
 410  * rundir (e.g. /usr/local/var/run/openvswitch).
 411  *
 412  * Returns 0 if successful, otherwise a positive errno value.  If successful,
 413  * sets '*client' to the new jsonrpc, otherwise to NULL. */
 414 int
 415 unixctl_client_create(const char *path, struct jsonrpc **client)
 416 {
 417     char *abs_path, *unix_path;
 418     struct stream *stream;
 419     int error;
 420
 421     *client = NULL;
 422
 423     abs_path = abs_file_name(ovs_rundir(), path);
 424     unix_path = xasprintf("unix:%s", abs_path);
 425     error = stream_open_block(stream_open(unix_path, &stream, DSCP_DEFAULT),
 426                               &stream);
 427     free(unix_path);
 428     free(abs_path);
 429
 430     if (error) {
 431         VLOG_WARN("failed to connect to %s", path);
 432         return error;
 433     }
 434
 435     *client = jsonrpc_open(stream);
 436     return 0;
 437 }
 438
 439 /* Executes 'command' on the server with an argument vector 'argv' containing
 440  * 'argc' elements.  If successfully communicated with the server, returns 0
 441  * and sets '*result', or '*err' (not both) to the result or error the server
 442  * returned.  Otherwise, sets '*result' and '*err' to NULL and returns a
 443  * positive errno value.  The caller is responsible for freeing '*result' or
 444  * '*err' if not NULL. */
 445 int
 446 unixctl_client_transact(struct jsonrpc *client, const char *command, int argc,
 447                         char *argv[], char **result, char **err)
 448 {
 449     struct jsonrpc_msg *request, *reply;
 450     struct json **json_args, *params;
 451     int error, i;
 452
 453     *result = NULL;
 454     *err = NULL;
 455
 456     json_args = xmalloc(argc * sizeof *json_args);
 457     for (i = 0; i < argc; i++) {
 458         json_args[i] = json_string_create(argv[i]);
 459     }
 460     params = json_array_create(json_args, argc);
 461     request = jsonrpc_create_request(command, params, NULL);
 462
 463     error = jsonrpc_transact_block(client, request, &reply);
 464     if (error) {
 465         VLOG_WARN("error communicating with %s: %s", jsonrpc_get_name(client),
 466                   strerror(error));
 467         return error;
 468     }
 469
 470     if (reply->error) {
 471         if (reply->error->type == JSON_STRING) {
 472             *err = xstrdup(json_string(reply->error));
 473         } else {
 474             VLOG_WARN("%s: unexpected error type in JSON RPC reply: %s",
 475                       jsonrpc_get_name(client),
 476                       json_type_to_string(reply->error->type));
 477             error = EINVAL;
 478         }
 479     } else if (reply->result) {
 480         if (reply->result->type == JSON_STRING) {
 481             *result = xstrdup(json_string(reply->result));
 482         } else {
 483             VLOG_WARN("%s: unexpected result type in JSON rpc reply: %s",
 484                       jsonrpc_get_name(client),
 485                       json_type_to_string(reply->result->type));
 486             error = EINVAL;
 487         }
 488     }
 489
 490     jsonrpc_msg_destroy(reply);
 491     return error;
 492 }