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