libustcomm/ustcomm.c

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