lib/unixctl.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010 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 <ctype.h>
  21 #include <errno.h>
  22 #include <poll.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/socket.h>
  26 #include <sys/stat.h>
  27 #include <unistd.h>
  28 #include "coverage.h"
  29 #include "dirs.h"
  30 #include "dynamic-string.h"
  31 #include "fatal-signal.h"
  32 #include "list.h"
  33 #include "ofpbuf.h"
  34 #include "poll-loop.h"
  35 #include "shash.h"
  36 #include "socket-util.h"
  37 #include "util.h"
  38
  39 #ifndef SCM_CREDENTIALS
  40 #include <time.h>
  41 #endif
  42
  43 #define THIS_MODULE VLM_unixctl
  44 #include "vlog.h"
  45 \f
  46 struct unixctl_command {
  47     unixctl_cb_func *cb;
  48     void *aux;
  49 };
  50
  51 struct unixctl_conn {
  52     struct list node;
  53     int fd;
  54
  55     enum { S_RECV, S_PROCESS, S_SEND } state;
  56     struct ofpbuf in;
  57     struct ds out;
  58     size_t out_pos;
  59 };
  60
  61 /* Server for control connection. */
  62 struct unixctl_server {
  63     char *path;
  64     int fd;
  65     struct list conns;
  66 };
  67
  68 /* Client for control connection. */
  69 struct unixctl_client {
  70     char *connect_path;
  71     char *bind_path;
  72     FILE *stream;
  73 };
  74
  75 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
  76
  77 static struct shash commands = SHASH_INITIALIZER(&commands);
  78
  79 static void
  80 unixctl_help(struct unixctl_conn *conn, const char *args OVS_UNUSED,
  81              void *aux OVS_UNUSED)
  82 {
  83     struct ds ds = DS_EMPTY_INITIALIZER;
  84     struct shash_node *node;
  85
  86     ds_put_cstr(&ds, "The available commands are:\n");
  87     SHASH_FOR_EACH (node, &commands) {
  88         ds_put_format(&ds, "\t%s\n", node->name);
  89     }
  90     unixctl_command_reply(conn, 214, ds_cstr(&ds));
  91     ds_destroy(&ds);
  92 }
  93
  94 void
  95 unixctl_command_register(const char *name, unixctl_cb_func *cb, void *aux)
  96 {
  97     struct unixctl_command *command;
  98
  99     assert(!shash_find_data(&commands, name)
 100            || shash_find_data(&commands, name) == cb);
 101     command = xmalloc(sizeof *command);
 102     command->cb = cb;
 103     command->aux = aux;
 104     shash_add(&commands, name, command);
 105 }
 106
 107 static const char *
 108 translate_reply_code(int code)
 109 {
 110     switch (code) {
 111     case 200: return "OK";
 112     case 201: return "Created";
 113     case 202: return "Accepted";
 114     case 204: return "No Content";
 115     case 211: return "System Status";
 116     case 214: return "Help";
 117     case 400: return "Bad Request";
 118     case 401: return "Unauthorized";
 119     case 403: return "Forbidden";
 120     case 404: return "Not Found";
 121     case 500: return "Internal Server Error";
 122     case 501: return "Invalid Argument";
 123     case 503: return "Service Unavailable";
 124     default: return "Unknown";
 125     }
 126 }
 127
 128 void
 129 unixctl_command_reply(struct unixctl_conn *conn,
 130                       int code, const char *body)
 131 {
 132     struct ds *out = &conn->out;
 133
 134     COVERAGE_INC(unixctl_replied);
 135     assert(conn->state == S_PROCESS);
 136     conn->state = S_SEND;
 137     conn->out_pos = 0;
 138
 139     ds_clear(out);
 140     ds_put_format(out, "%03d %s\n", code, translate_reply_code(code));
 141     if (body) {
 142         const char *p;
 143         for (p = body; *p != '\0'; ) {
 144             size_t n = strcspn(p, "\n");
 145
 146             if (*p == '.') {
 147                 ds_put_char(out, '.');
 148             }
 149             ds_put_buffer(out, p, n);
 150             ds_put_char(out, '\n');
 151             p += n;
 152             if (*p == '\n') {
 153                 p++;
 154             }
 155         }
 156     }
 157     ds_put_cstr(out, ".\n");
 158 }
 159
 160 /* Creates a unixctl server listening on 'path', which may be:
 161  *
 162  *      - NULL, in which case <rundir>/<program>.<pid>.ctl is used.
 163  *
 164  *      - A name that does not start with '/', in which case it is put in
 165  *        <rundir>.
 166  *
 167  *      - An absolute path (starting with '/') that gives the exact name of
 168  *        the Unix domain socket to listen on.
 169  *
 170  * A program that (optionally) daemonizes itself should call this function
 171  * *after* daemonization, so that the socket name contains the pid of the
 172  * daemon instead of the pid of the program that exited.  (Otherwise,
 173  * "ovs-appctl --target=<program>" will fail.)
 174  *
 175  * Returns 0 if successful, otherwise a positive errno value.  If successful,
 176  * sets '*serverp' to the new unixctl_server, otherwise to NULL. */
 177 int
 178 unixctl_server_create(const char *path, struct unixctl_server **serverp)
 179 {
 180     struct unixctl_server *server;
 181     int error;
 182
 183     unixctl_command_register("help", unixctl_help, NULL);
 184
 185     server = xmalloc(sizeof *server);
 186     list_init(&server->conns);
 187
 188     if (path) {
 189         if (path[0] == '/') {
 190             server->path = xstrdup(path);
 191         } else {
 192             server->path = xasprintf("%s/%s", ovs_rundir, path);
 193         }
 194     } else {
 195         server->path = xasprintf("%s/%s.%ld.ctl", ovs_rundir,
 196                                  program_name, (long int) getpid());
 197     }
 198
 199     server->fd = make_unix_socket(SOCK_STREAM, true, false, server->path,
 200                                   NULL);
 201     if (server->fd < 0) {
 202         error = -server->fd;
 203         ovs_error(error, "could not initialize control socket %s",
 204                   server->path);
 205         goto error;
 206     }
 207
 208     if (chmod(server->path, S_IRUSR | S_IWUSR) < 0) {
 209         error = errno;
 210         ovs_error(error, "failed to chmod control socket %s", server->path);
 211         goto error;
 212     }
 213
 214     if (listen(server->fd, 10) < 0) {
 215         error = errno;
 216         ovs_error(error, "Failed to listen on control socket %s",
 217                   server->path);
 218         goto error;
 219     }
 220
 221     *serverp = server;
 222     return 0;
 223
 224 error:
 225     if (server->fd >= 0) {
 226         close(server->fd);
 227     }
 228     free(server->path);
 229     free(server);
 230     *serverp = NULL;
 231     return error;
 232 }
 233
 234 static void
 235 new_connection(struct unixctl_server *server, int fd)
 236 {
 237     struct unixctl_conn *conn;
 238
 239     set_nonblocking(fd);
 240
 241     conn = xmalloc(sizeof *conn);
 242     list_push_back(&server->conns, &conn->node);
 243     conn->fd = fd;
 244     conn->state = S_RECV;
 245     ofpbuf_init(&conn->in, 128);
 246     ds_init(&conn->out);
 247     conn->out_pos = 0;
 248 }
 249
 250 static int
 251 run_connection_output(struct unixctl_conn *conn)
 252 {
 253     while (conn->out_pos < conn->out.length) {
 254         size_t bytes_written;
 255         int error;
 256
 257         error = write_fully(conn->fd, conn->out.string + conn->out_pos,
 258                             conn->out.length - conn->out_pos, &bytes_written);
 259         conn->out_pos += bytes_written;
 260         if (error) {
 261             return error;
 262         }
 263     }
 264     conn->state = S_RECV;
 265     return 0;
 266 }
 267
 268 static void
 269 process_command(struct unixctl_conn *conn, char *s)
 270 {
 271     struct unixctl_command *command;
 272     size_t name_len;
 273     char *name, *args;
 274
 275     COVERAGE_INC(unixctl_received);
 276     conn->state = S_PROCESS;
 277
 278     name = s;
 279     name_len = strcspn(name, " ");
 280     args = name + name_len;
 281     args += strspn(args, " ");
 282     name[name_len] = '\0';
 283
 284     command = shash_find_data(&commands, name);
 285     if (command) {
 286         command->cb(conn, args, command->aux);
 287     } else {
 288         char *msg = xasprintf("\"%s\" is not a valid command", name);
 289         unixctl_command_reply(conn, 400, msg);
 290         free(msg);
 291     }
 292 }
 293
 294 static int
 295 run_connection_input(struct unixctl_conn *conn)
 296 {
 297     for (;;) {
 298         size_t bytes_read;
 299         char *newline;
 300         int error;
 301
 302         newline = memchr(conn->in.data, '\n', conn->in.size);
 303         if (newline) {
 304             char *command = conn->in.data;
 305             size_t n = newline - command + 1;
 306
 307             if (n > 0 && newline[-1] == '\r') {
 308                 newline--;
 309             }
 310             *newline = '\0';
 311
 312             process_command(conn, command);
 313
 314             ofpbuf_pull(&conn->in, n);
 315             if (!conn->in.size) {
 316                 ofpbuf_clear(&conn->in);
 317             }
 318             return 0;
 319         }
 320
 321         ofpbuf_prealloc_tailroom(&conn->in, 128);
 322         error = read_fully(conn->fd, ofpbuf_tail(&conn->in),
 323                            ofpbuf_tailroom(&conn->in), &bytes_read);
 324         conn->in.size += bytes_read;
 325         if (conn->in.size > 65536) {
 326             VLOG_WARN_RL(&rl, "excess command length, killing connection");
 327             return EPROTO;
 328         }
 329         if (error) {
 330             if (error == EAGAIN || error == EWOULDBLOCK) {
 331                 if (!bytes_read) {
 332                     return EAGAIN;
 333                 }
 334             } else {
 335                 if (error != EOF || conn->in.size != 0) {
 336                     VLOG_WARN_RL(&rl, "read failed: %s",
 337                                  (error == EOF
 338                                   ? "connection dropped mid-command"
 339                                   : strerror(error)));
 340                 }
 341                 return error;
 342             }
 343         }
 344     }
 345 }
 346
 347 static int
 348 run_connection(struct unixctl_conn *conn)
 349 {
 350     int old_state;
 351     do {
 352         int error;
 353
 354         old_state = conn->state;
 355         switch (conn->state) {
 356         case S_RECV:
 357             error = run_connection_input(conn);
 358             break;
 359
 360         case S_PROCESS:
 361             error = 0;
 362             break;
 363
 364         case S_SEND:
 365             error = run_connection_output(conn);
 366             break;
 367
 368         default:
 369             NOT_REACHED();
 370         }
 371         if (error) {
 372             return error;
 373         }
 374     } while (conn->state != old_state);
 375     return 0;
 376 }
 377
 378 static void
 379 kill_connection(struct unixctl_conn *conn)
 380 {
 381     list_remove(&conn->node);
 382     ofpbuf_uninit(&conn->in);
 383     ds_destroy(&conn->out);
 384     close(conn->fd);
 385     free(conn);
 386 }
 387
 388 void
 389 unixctl_server_run(struct unixctl_server *server)
 390 {
 391     struct unixctl_conn *conn, *next;
 392     int i;
 393
 394     for (i = 0; i < 10; i++) {
 395         int fd = accept(server->fd, NULL, NULL);
 396         if (fd < 0) {
 397             if (errno != EAGAIN && errno != EWOULDBLOCK) {
 398                 VLOG_WARN_RL(&rl, "accept failed: %s", strerror(errno));
 399             }
 400             break;
 401         }
 402         new_connection(server, fd);
 403     }
 404
 405     LIST_FOR_EACH_SAFE (conn, next,
 406                         struct unixctl_conn, node, &server->conns) {
 407         int error = run_connection(conn);
 408         if (error && error != EAGAIN) {
 409             kill_connection(conn);
 410         }
 411     }
 412 }
 413
 414 void
 415 unixctl_server_wait(struct unixctl_server *server)
 416 {
 417     struct unixctl_conn *conn;
 418
 419     poll_fd_wait(server->fd, POLLIN);
 420     LIST_FOR_EACH (conn, struct unixctl_conn, node, &server->conns) {
 421         if (conn->state == S_RECV) {
 422             poll_fd_wait(conn->fd, POLLIN);
 423         } else if (conn->state == S_SEND) {
 424             poll_fd_wait(conn->fd, POLLOUT);
 425         }
 426     }
 427 }
 428
 429 /* Destroys 'server' and stops listening for connections. */
 430 void
 431 unixctl_server_destroy(struct unixctl_server *server)
 432 {
 433     if (server) {
 434         struct unixctl_conn *conn, *next;
 435
 436         LIST_FOR_EACH_SAFE (conn, next,
 437                             struct unixctl_conn, node, &server->conns) {
 438             kill_connection(conn);
 439         }
 440
 441         close(server->fd);
 442         fatal_signal_unlink_file_now(server->path);
 443         free(server->path);
 444         free(server);
 445     }
 446 }
 447 \f
 448 /* Connects to a Vlog server socket.  'path' should be the name of a Vlog
 449  * server socket.  If it does not start with '/', it will be prefixed with
 450  * ovs_rundir (e.g. /var/run).
 451  *
 452  * Returns 0 if successful, otherwise a positive errno value.  If successful,
 453  * sets '*clientp' to the new unixctl_client, otherwise to NULL. */
 454 int
 455 unixctl_client_create(const char *path, struct unixctl_client **clientp)
 456 {
 457     static int counter;
 458     struct unixctl_client *client;
 459     int error;
 460     int fd = -1;
 461
 462     /* Determine location. */
 463     client = xmalloc(sizeof *client);
 464     if (path[0] == '/') {
 465         client->connect_path = xstrdup(path);
 466     } else {
 467         client->connect_path = xasprintf("%s/%s", ovs_rundir, path);
 468     }
 469     client->bind_path = xasprintf("/tmp/vlog.%ld.%d",
 470                                   (long int) getpid(), counter++);
 471
 472     /* Open socket. */
 473     fd = make_unix_socket(SOCK_STREAM, false, false,
 474                           client->bind_path, client->connect_path);
 475     if (fd < 0) {
 476         error = -fd;
 477         goto error;
 478     }
 479
 480     /* Bind socket to stream. */
 481     client->stream = fdopen(fd, "r+");
 482     if (!client->stream) {
 483         error = errno;
 484         VLOG_WARN("%s: fdopen failed (%s)",
 485                   client->connect_path, strerror(error));
 486         goto error;
 487     }
 488     *clientp = client;
 489     return 0;
 490
 491 error:
 492     if (fd >= 0) {
 493         close(fd);
 494     }
 495     free(client->connect_path);
 496     free(client->bind_path);
 497     free(client);
 498     *clientp = NULL;
 499     return error;
 500 }
 501
 502 /* Destroys 'client'. */
 503 void
 504 unixctl_client_destroy(struct unixctl_client *client)
 505 {
 506     if (client) {
 507         fatal_signal_unlink_file_now(client->bind_path);
 508         free(client->bind_path);
 509         free(client->connect_path);
 510         fclose(client->stream);
 511         free(client);
 512     }
 513 }
 514
 515 /* Sends 'request' to the server socket and waits for a reply.  Returns 0 if
 516  * successful, otherwise to a positive errno value.  If successful, sets
 517  * '*reply' to the reply, which the caller must free, otherwise to NULL. */
 518 int
 519 unixctl_client_transact(struct unixctl_client *client,
 520                         const char *request,
 521                         int *reply_code, char **reply_body)
 522 {
 523     struct ds line = DS_EMPTY_INITIALIZER;
 524     struct ds reply = DS_EMPTY_INITIALIZER;
 525     int error;
 526
 527     /* Send 'request' to server.  Add a new-line if 'request' didn't end in
 528      * one. */
 529     fputs(request, client->stream);
 530     if (request[0] == '\0' || request[strlen(request) - 1] != '\n') {
 531         putc('\n', client->stream);
 532     }
 533     if (ferror(client->stream)) {
 534         VLOG_WARN("error sending request to %s: %s",
 535                   client->connect_path, strerror(errno));
 536         return errno;
 537     }
 538
 539     /* Wait for response. */
 540     *reply_code = -1;
 541     for (;;) {
 542         const char *s;
 543
 544         error = ds_get_line(&line, client->stream);
 545         if (error) {
 546             VLOG_WARN("error reading reply from %s: %s",
 547                       client->connect_path,
 548                       (error == EOF ? "unexpected end of file"
 549                        : strerror(error)));
 550             goto error;
 551         }
 552
 553         s = ds_cstr(&line);
 554         if (*reply_code == -1) {
 555             if (!isdigit((unsigned char)s[0])
 556                     || !isdigit((unsigned char)s[1])
 557                     || !isdigit((unsigned char)s[2])) {
 558                 VLOG_WARN("reply from %s does not start with 3-digit code",
 559                           client->connect_path);
 560                 error = EPROTO;
 561                 goto error;
 562             }
 563             sscanf(s, "%3d", reply_code);
 564         } else {
 565             if (s[0] == '.') {
 566                 if (s[1] == '\0') {
 567                     break;
 568                 }
 569                 s++;
 570             }
 571             ds_put_cstr(&reply, s);
 572             ds_put_char(&reply, '\n');
 573         }
 574     }
 575     *reply_body = ds_cstr(&reply);
 576     ds_destroy(&line);
 577     return 0;
 578
 579 error:
 580     ds_destroy(&line);
 581     ds_destroy(&reply);
 582     *reply_code = 0;
 583     *reply_body = NULL;
 584     return error == EOF ? EPROTO : error;
 585 }
 586
 587 /* Returns the path of the server socket to which 'client' is connected.  The
 588  * caller must not modify or free the returned string. */
 589 const char *
 590 unixctl_client_target(const struct unixctl_client *client)
 591 {
 592     return client->connect_path;
 593 }