libustcomm/ustcomm.c

   1 /* Copyright (C) 2009  Pierre-Marc Fournier
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <sys/types.h>
  20 #include <signal.h>
  21 #include <errno.h>
  22 #include <sys/socket.h>
  23 #include <sys/un.h>
  24 #include <unistd.h>
  25 #include <poll.h>
  26
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <execinfo.h>
  31
  32 #include "ustcomm.h"
  33 #include "localerr.h"
  34
  35 #define UNIX_PATH_MAX 108
  36
  37 #define MSG_MAX 1000
  38
  39 /* FIXME: ustcomm blocks on message sending, which might be problematic in
  40  * some cases. Fix the poll() usage so sends are buffered until they don't
  41  * block.
  42  */
  43
  44 //static void bt(void)
  45 //{
  46 //      void *buffer[100];
  47 //      int result;
  48 //
  49 //      result = backtrace(&buffer, 100);
  50 //      backtrace_symbols_fd(buffer, result, STDERR_FILENO);
  51 //}
  52
  53 char *strdup_malloc(const char *s)
  54 {
  55         char *retval;
  56
  57         if(s == NULL)
  58                 return NULL;
  59
  60         retval = (char *) malloc(strlen(s)+1);
  61
  62         strcpy(retval, s);
  63
  64         return retval;
  65 }
  66
  67 static int signal_process(pid_t pid)
  68 {
  69         int result;
  70
  71         result = kill(pid, UST_SIGNAL);
  72         if(result == -1) {
  73                 PERROR("kill");
  74                 return -1;
  75         }
  76
  77         /* FIXME: should wait in a better way */
  78         //sleep(1);
  79
  80         return 0;
  81 }
  82
  83 int pid_is_online(pid_t pid) {
  84         return kill(pid, UST_SIGNAL) != -1;
  85 }
  86
  87 static int send_message_fd(int fd, const char *msg)
  88 {
  89         int result;
  90
  91         result = send(fd, msg, strlen(msg), 0);
  92         if(result == -1) {
  93                 PERROR("send");
  94                 return -1;
  95         }
  96         else if(result == 0) {
  97                 return 0;
  98         }
  99
 100         return 1;
 101 }
 102
 103 /* Called by an app to ask the consumer daemon to connect to it. */
 104
 105 int ustcomm_request_consumer(pid_t pid, const char *channel)
 106 {
 107         char path[UNIX_PATH_MAX];
 108         int result;
 109         char *msg=NULL;
 110         int retval = 0;
 111         struct ustcomm_connection conn;
 112         char *explicit_daemon_socket_path;
 113
 114         explicit_daemon_socket_path = getenv("UST_DAEMON_SOCKET");
 115         if(explicit_daemon_socket_path) {
 116                 /* user specified explicitly a socket path */
 117                 result = snprintf(path, UNIX_PATH_MAX, "%s", explicit_daemon_socket_path);
 118         }
 119         else {
 120                 /* just use the default path */
 121                 result = snprintf(path, UNIX_PATH_MAX, "%s/ustd", SOCK_DIR);
 122         }
 123
 124         if(result >= UNIX_PATH_MAX) {
 125                 ERR("string overflow allocating socket name");
 126                 return -1;
 127         }
 128
 129         asprintf(&msg, "collect %d %s", pid, channel);
 130
 131         /* don't signal it because it's the daemon */
 132         result = ustcomm_connect_path(path, &conn, -1);
 133         if(result == -1) {
 134                 WARN("ustcomm_connect_path failed");
 135                 retval = -1;
 136                 goto del_string;
 137         }
 138
 139         result = ustcomm_send_request(&conn, msg, NULL);
 140         if(result == -1) {
 141                 WARN("ustcomm_send_request failed");
 142                 retval = -1;
 143                 goto disconnect;
 144         }
 145
 146         disconnect:
 147         ustcomm_disconnect(&conn);
 148         del_string:
 149         free(msg);
 150
 151         return retval;
 152 }
 153
 154 /* returns 1 to indicate a message was received
 155  * returns 0 to indicate no message was received (cannot happen)
 156  * returns -1 to indicate an error
 157  */
 158
 159 static int recv_message_fd(int fd, char **msg, struct ustcomm_source *src)
 160 {
 161         int result;
 162
 163         *msg = (char *) malloc(MSG_MAX+1);
 164
 165         result = recv(fd, *msg, MSG_MAX, 0);
 166         if(result == -1) {
 167                 PERROR("recv");
 168                 return -1;
 169         }
 170
 171         (*msg)[result] = '\0';
 172
 173         DBG("ustcomm_app_recv_message: result is %d, message is %s", result, (*msg));
 174
 175         if(src)
 176                 src->fd = fd;
 177
 178         return 1;
 179 }
 180
 181 int ustcomm_send_reply(struct ustcomm_server *server, char *msg, struct ustcomm_source *src)
 182 {
 183         int result;
 184
 185         result = send_message_fd(src->fd, msg);
 186         if(result < 0) {
 187                 ERR("error in send_message_fd");
 188                 return -1;
 189         }
 190
 191         return 0;
 192 }
 193
 194 /* Called after a fork. */
 195
 196 int ustcomm_close_all_connections(struct ustcomm_server *server)
 197 {
 198         struct ustcomm_connection *conn;
 199         struct ustcomm_connection *deletable_conn = NULL;
 200
 201         list_for_each_entry(conn, &server->connections, list) {
 202                 free(deletable_conn);
 203                 deletable_conn = conn;
 204                 close(conn->fd);
 205                 list_del(&conn->list);
 206         }
 207
 208         return 0;
 209 }
 210
 211 /* @timeout: max blocking time in milliseconds, -1 means infinity
 212  *
 213  * returns 1 to indicate a message was received
 214  * returns 0 to indicate no message was received
 215  * returns -1 to indicate an error
 216  */
 217
 218 int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustcomm_source *src, int timeout)
 219 {
 220         struct pollfd *fds;
 221         struct ustcomm_connection *conn;
 222         int result;
 223         int retval;
 224
 225         for(;;) {
 226                 int idx = 0;
 227                 int n_fds = 1;
 228
 229                 list_for_each_entry(conn, &server->connections, list) {
 230                         n_fds++;
 231                 }
 232
 233                 fds = (struct pollfd *) malloc(n_fds * sizeof(struct pollfd));
 234                 if(fds == NULL) {
 235                         ERR("malloc returned NULL");
 236                         return -1;
 237                 }
 238
 239                 /* special idx 0 is for listening socket */
 240                 fds[idx].fd = server->listen_fd;
 241                 fds[idx].events = POLLIN;
 242                 idx++;
 243
 244                 list_for_each_entry(conn, &server->connections, list) {
 245                         fds[idx].fd = conn->fd;
 246                         fds[idx].events = POLLIN;
 247                         idx++;
 248                 }
 249
 250                 while((result = poll(fds, n_fds, timeout)) == -1 && errno == EINTR)
 251                         /* nothing */;
 252                 if(result == -1) {
 253                         PERROR("poll");
 254                         return -1;
 255                 }
 256
 257                 if(result == 0)
 258                         return 0;
 259
 260                 if(fds[0].revents) {
 261                         struct ustcomm_connection *newconn;
 262                         int newfd;
 263
 264                         result = newfd = accept(server->listen_fd, NULL, NULL);
 265                         if(result == -1) {
 266                                 PERROR("accept");
 267                                 return -1;
 268                         }
 269
 270                         newconn = (struct ustcomm_connection *) malloc(sizeof(struct ustcomm_connection));
 271                         if(newconn == NULL) {
 272                                 ERR("malloc returned NULL");
 273                                 return -1;
 274                         }
 275
 276                         newconn->fd = newfd;
 277
 278                         list_add(&newconn->list, &server->connections);
 279                 }
 280
 281                 for(idx=1; idx<n_fds; idx++) {
 282                         if(fds[idx].revents) {
 283                                 retval = recv_message_fd(fds[idx].fd, msg, src);
 284                                 if(**msg == 0) {
 285                                         /* connection finished */
 286                                         close(fds[idx].fd);
 287
 288                                         list_for_each_entry(conn, &server->connections, list) {
 289                                                 if(conn->fd == fds[idx].fd) {
 290                                                         list_del(&conn->list);
 291                                                         break;
 292                                                 }
 293                                         }
 294                                 }
 295                                 else {
 296                                         goto free_fds_return;
 297                                 }
 298                         }
 299                 }
 300
 301                 free(fds);
 302         }
 303
 304 free_fds_return:
 305         free(fds);
 306         return retval;
 307 }
 308
 309 int ustcomm_ustd_recv_message(struct ustcomm_ustd *ustd, char **msg, struct ustcomm_source *src, int timeout)
 310 {
 311         return ustcomm_recv_message(&ustd->server, msg, src, timeout);
 312 }
 313
 314 int ustcomm_app_recv_message(struct ustcomm_app *app, char **msg, struct ustcomm_source *src, int timeout)
 315 {
 316         return ustcomm_recv_message(&app->server, msg, src, timeout);
 317 }
 318
 319 /* This removes src from the list of active connections of app.
 320  */
 321
 322 int ustcomm_app_detach_client(struct ustcomm_app *app, struct ustcomm_source *src)
 323 {
 324         struct ustcomm_server *server = (struct ustcomm_server *)app;
 325         struct ustcomm_connection *conn;
 326
 327         list_for_each_entry(conn, &server->connections, list) {
 328                 if(conn->fd == src->fd) {
 329                         list_del(&conn->list);
 330                         goto found;
 331                 }
 332         }
 333
 334         return -1;
 335 found:
 336         return src->fd;
 337 }
 338
 339 static int init_named_socket(const char *name, char **path_out)
 340 {
 341         int result;
 342         int fd;
 343
 344         struct sockaddr_un addr;
 345
 346         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 347         if(result == -1) {
 348                 PERROR("socket");
 349                 return -1;
 350         }
 351
 352         addr.sun_family = AF_UNIX;
 353
 354         strncpy(addr.sun_path, name, UNIX_PATH_MAX);
 355         addr.sun_path[UNIX_PATH_MAX-1] = '\0';
 356
 357         result = access(name, F_OK);
 358         if(result == 0) {
 359                 /* file exists */
 360                 result = unlink(name);
 361                 if(result == -1) {
 362                         PERROR("unlink of socket file");
 363                         goto close_sock;
 364                 }
 365                 WARN("socket already exists; overwriting");
 366         }
 367
 368         result = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
 369         if(result == -1) {
 370                 PERROR("bind");
 371                 goto close_sock;
 372         }
 373
 374         result = listen(fd, 1);
 375         if(result == -1) {
 376                 PERROR("listen");
 377                 goto close_sock;
 378         }
 379
 380         if(path_out) {
 381                 *path_out = "";
 382                 *path_out = strdupa(addr.sun_path);
 383         }
 384
 385         return fd;
 386
 387         close_sock:
 388         close(fd);
 389
 390         return -1;
 391 }
 392
 393 int ustcomm_send_request(struct ustcomm_connection *conn, const char *req, char **reply)
 394 {
 395         int result;
 396
 397         result = send(conn->fd, req, strlen(req), 0);
 398         if(result == -1) {
 399                 PERROR("send");
 400                 return -1;
 401         }
 402
 403         if(!reply)
 404                 return 1;
 405
 406         *reply = (char *) malloc(MSG_MAX+1);
 407         result = recv(conn->fd, *reply, MSG_MAX, 0);
 408         if(result == -1) {
 409                 PERROR("recv");
 410                 return -1;
 411         }
 412         else if(result == 0) {
 413                 return 0;
 414         }
 415
 416         (*reply)[result] = '\0';
 417
 418         return 1;
 419 }
 420
 421 int ustcomm_connect_path(const char *path, struct ustcomm_connection *conn, pid_t signalpid)
 422 {
 423         int fd;
 424         int result;
 425         struct sockaddr_un addr;
 426
 427         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 428         if(result == -1) {
 429                 PERROR("socket");
 430                 return -1;
 431         }
 432
 433         addr.sun_family = AF_UNIX;
 434
 435         result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s", path);
 436         if(result >= UNIX_PATH_MAX) {
 437                 ERR("string overflow allocating socket name");
 438                 return -1;
 439         }
 440
 441         if(signalpid >= 0) {
 442                 result = signal_process(signalpid);
 443                 if(result == -1) {
 444                         ERR("could not signal process");
 445                         return -1;
 446                 }
 447         }
 448
 449         result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
 450         if(result == -1) {
 451                 PERROR("connect");
 452                 return -1;
 453         }
 454
 455         conn->fd = fd;
 456
 457         return 0;
 458 }
 459
 460 int ustcomm_disconnect(struct ustcomm_connection *conn)
 461 {
 462         return close(conn->fd);
 463 }
 464
 465 int ustcomm_connect_app(pid_t pid, struct ustcomm_connection *conn)
 466 {
 467         int result;
 468         char path[UNIX_PATH_MAX];
 469
 470
 471         result = snprintf(path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
 472         if(result >= UNIX_PATH_MAX) {
 473                 ERR("string overflow allocating socket name");
 474                 return -1;
 475         }
 476
 477         return ustcomm_connect_path(path, conn, pid);
 478 }
 479
 480 /* Called by an application to initialize its server so daemons can
 481  * connect to it.
 482  */
 483
 484 int ustcomm_init_app(pid_t pid, struct ustcomm_app *handle)
 485 {
 486         int result;
 487         char *name;
 488
 489         result = asprintf(&name, "%s/%d", SOCK_DIR, (int)pid);
 490         if(result >= UNIX_PATH_MAX) {
 491                 ERR("string overflow allocating socket name");
 492                 return -1;
 493         }
 494
 495         handle->server.listen_fd = init_named_socket(name, &(handle->server.socketpath));
 496         if(handle->server.listen_fd < 0) {
 497                 ERR("error initializing named socket");
 498                 goto free_name;
 499         }
 500         free(name);
 501
 502         INIT_LIST_HEAD(&handle->server.connections);
 503
 504         return 0;
 505
 506 free_name:
 507         free(name);
 508         return -1;
 509 }
 510
 511 /* Used by the daemon to initialize its server so applications
 512  * can connect to it.
 513  */
 514
 515 int ustcomm_init_ustd(struct ustcomm_ustd *handle, const char *sock_path)
 516 {
 517         char *name;
 518         int retval = 0;
 519
 520         if(sock_path) {
 521                 asprintf(&name, "%s", sock_path);
 522         }
 523         else {
 524                 asprintf(&name, "%s/%s", SOCK_DIR, "ustd");
 525         }
 526
 527         handle->server.listen_fd = init_named_socket(name, &handle->server.socketpath);
 528         if(handle->server.listen_fd < 0) {
 529                 ERR("error initializing named socket at %s", name);
 530                 retval = -1;
 531                 goto free_name;
 532         }
 533
 534         INIT_LIST_HEAD(&handle->server.connections);
 535
 536 free_name:
 537         free(name);
 538
 539         return retval;
 540 }
 541
 542 static char *find_tok(char *str)
 543 {
 544         while(*str == ' ') {
 545                 str++;
 546
 547                 if(*str == 0)
 548                         return NULL;
 549         }
 550
 551         return str;
 552 }
 553
 554 static char *find_sep(char *str)
 555 {
 556         while(*str != ' ') {
 557                 str++;
 558
 559                 if(*str == 0)
 560                         break;
 561         }
 562
 563         return str;
 564 }
 565
 566 int nth_token_is(char *str, char *token, int tok_no)
 567 {
 568         int i;
 569         char *start;
 570         char *end;
 571
 572         for(i=0; i<=tok_no; i++) {
 573                 str = find_tok(str);
 574                 if(str == NULL)
 575                         return -1;
 576
 577                 start = str;
 578
 579                 str = find_sep(str);
 580                 if(str == NULL)
 581                         return -1;
 582
 583                 end = str;
 584         }
 585
 586         if(end-start != strlen(token))
 587                 return 0;
 588
 589         if(strncmp(start, token, end-start))
 590                 return 0;
 591
 592         return 1;
 593 }
 594
 595 char *nth_token(char *str, int tok_no)
 596 {
 597         static char *retval = NULL;
 598         int i;
 599         char *start;
 600         char *end;
 601
 602         for(i=0; i<=tok_no; i++) {
 603                 str = find_tok(str);
 604                 if(str == NULL)
 605                         return NULL;
 606
 607                 start = str;
 608
 609                 str = find_sep(str);
 610                 if(str == NULL)
 611                         return NULL;
 612
 613                 end = str;
 614         }
 615
 616         if(retval) {
 617                 free(retval);
 618                 retval = NULL;
 619         }
 620
 621         asprintf(&retval, "%.*s", (int)(end-start), start);
 622
 623         return retval;
 624 }
 625