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 #define SOCK_DIR "/tmp/socks"
  37 #define UST_SIGNAL SIGIO
  38
  39 #define MSG_MAX 1000
  40
  41 /* FIXME: ustcomm blocks on message sending, which might be problematic in
  42  * some cases. Fix the poll() usage so sends are buffered until they don't
  43  * block.
  44  */
  45
  46 //static void bt(void)
  47 //{
  48 //      void *buffer[100];
  49 //      int result;
  50 //
  51 //      result = backtrace(&buffer, 100);
  52 //      backtrace_symbols_fd(buffer, result, STDERR_FILENO);
  53 //}
  54
  55 char *strdup_malloc(const char *s)
  56 {
  57         char *retval;
  58
  59         if(s == NULL)
  60                 return NULL;
  61
  62         retval = (char *) malloc(strlen(s)+1);
  63
  64         strcpy(retval, s);
  65
  66         return retval;
  67 }
  68
  69 static int signal_process(pid_t pid)
  70 {
  71         int result;
  72
  73         result = kill(pid, UST_SIGNAL);
  74         if(result == -1) {
  75                 PERROR("kill");
  76                 return -1;
  77         }
  78
  79         /* FIXME: should wait in a better way */
  80         //sleep(1);
  81
  82         return 0;
  83 }
  84
  85 static int send_message_fd(int fd, const char *msg)
  86 {
  87         int result;
  88
  89         result = send(fd, msg, strlen(msg), 0);
  90         if(result == -1) {
  91                 PERROR("send");
  92                 return -1;
  93         }
  94         else if(result == 0) {
  95                 return 0;
  96         }
  97
  98         return 1;
  99
 100 //      *reply = (char *) malloc(MSG_MAX+1);
 101 //      result = recv(fd, *reply, MSG_MAX, 0);
 102 //      if(result == -1) {
 103 //              PERROR("recv");
 104 //              return -1;
 105 //      }
 106 //      else if(result == 0) {
 107 //              return 0;
 108 //      }
 109 //
 110 //      (*reply)[result] = '\0';
 111 //
 112 //      return 1;
 113 }
 114
 115 static int send_message_path(const char *path, const char *msg, int signalpid)
 116 {
 117         int fd;
 118         int result;
 119         struct sockaddr_un addr;
 120
 121         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 122         if(result == -1) {
 123                 PERROR("socket");
 124                 return -1;
 125         }
 126
 127         addr.sun_family = AF_UNIX;
 128
 129         result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s", path);
 130         if(result >= UNIX_PATH_MAX) {
 131                 ERR("string overflow allocating socket name");
 132                 return -1;
 133         }
 134
 135         if(signalpid >= 0) {
 136                 result = signal_process(signalpid);
 137                 if(result == -1) {
 138                         ERR("could not signal process");
 139                         return -1;
 140                 }
 141         }
 142
 143         result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
 144         if(result == -1) {
 145                 PERROR("connect");
 146                 return -1;
 147         }
 148
 149         return send_message_fd(fd, msg);
 150 }
 151
 152 ///* pid: the pid of the trace process that must receive the msg
 153 //   msg: pointer to a null-terminated message to send
 154 //   reply: location where to put the null-terminated string of the reply;
 155 //        it must be free'd after usage
 156 // */
 157 //
 158 //int send_message_pid(pid_t pid, const char *msg, char **reply)
 159 //{
 160 //      int result;
 161 //      char path[UNIX_PATH_MAX];
 162 //
 163 //      result = snprintf(path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
 164 //      if(result >= UNIX_PATH_MAX) {
 165 //              fprintf(stderr, "string overflow allocating socket name");
 166 //              return -1;
 167 //      }
 168 //
 169 //      send_message_path(path, msg, reply, pid);
 170 //
 171 //      return 0;
 172 //}
 173
 174 /* Called by an app to ask the consumer daemon to connect to it. */
 175
 176 int ustcomm_request_consumer(pid_t pid, const char *channel)
 177 {
 178         char path[UNIX_PATH_MAX];
 179         int result;
 180         char *msg;
 181
 182         result = snprintf(path, UNIX_PATH_MAX, "%s/ustd", SOCK_DIR);
 183         if(result >= UNIX_PATH_MAX) {
 184                 fprintf(stderr, "string overflow allocating socket name");
 185                 return -1;
 186         }
 187
 188         asprintf(&msg, "collect %d %s", pid, channel);
 189
 190         send_message_path(path, msg, -1);
 191         free(msg);
 192
 193         return 0;
 194 }
 195
 196 /* returns 1 to indicate a message was received
 197  * returns 0 to indicate no message was received (cannot happen)
 198  * returns -1 to indicate an error
 199  */
 200
 201 static int recv_message_fd(int fd, char **msg, struct ustcomm_source *src)
 202 {
 203         int result;
 204
 205         *msg = (char *) malloc(MSG_MAX+1);
 206
 207         result = recv(fd, *msg, MSG_MAX, 0);
 208         if(result == -1) {
 209                 PERROR("recv");
 210                 return -1;
 211         }
 212
 213         (*msg)[result] = '\0';
 214
 215         DBG("ustcomm_app_recv_message: result is %d, message is %s", result, (*msg));
 216
 217         if(src)
 218                 src->fd = fd;
 219
 220         return 1;
 221 }
 222
 223 int ustcomm_send_reply(struct ustcomm_server *server, char *msg, struct ustcomm_source *src)
 224 {
 225         int result;
 226
 227         result = send_message_fd(src->fd, msg);
 228         if(result < 0) {
 229                 ERR("error in send_message_fd");
 230                 return -1;
 231         }
 232
 233         return 0;
 234 }
 235
 236 /* @timeout: max blocking time in milliseconds, -1 means infinity
 237  *
 238  * returns 1 to indicate a message was received
 239  * returns 0 to indicate no message was received
 240  * returns -1 to indicate an error
 241  */
 242
 243 int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustcomm_source *src, int timeout)
 244 {
 245         struct pollfd *fds;
 246         struct ustcomm_connection *conn;
 247         int result;
 248         int retval;
 249
 250         for(;;) {
 251                 int idx = 0;
 252                 int n_fds = 1;
 253
 254                 list_for_each_entry(conn, &server->connections, list) {
 255                         n_fds++;
 256                 }
 257
 258                 fds = (struct pollfd *) malloc(n_fds * sizeof(struct pollfd));
 259                 if(fds == NULL) {
 260                         ERR("malloc returned NULL");
 261                         return -1;
 262                 }
 263
 264                 /* special idx 0 is for listening socket */
 265                 fds[idx].fd = server->listen_fd;
 266                 fds[idx].events = POLLIN;
 267                 idx++;
 268
 269                 list_for_each_entry(conn, &server->connections, list) {
 270                         fds[idx].fd = conn->fd;
 271                         fds[idx].events = POLLIN;
 272                         idx++;
 273                 }
 274
 275                 result = poll(fds, n_fds, timeout);
 276                 if(result == -1) {
 277                         PERROR("poll");
 278                         return -1;
 279                 }
 280
 281                 if(result == 0)
 282                         return 0;
 283
 284                 if(fds[0].revents) {
 285                         struct ustcomm_connection *newconn;
 286                         int newfd;
 287
 288                         result = newfd = accept(server->listen_fd, NULL, NULL);
 289                         if(result == -1) {
 290                                 PERROR("accept");
 291                                 return -1;
 292                         }
 293
 294                         newconn = (struct ustcomm_connection *) malloc(sizeof(struct ustcomm_connection));
 295                         if(newconn == NULL) {
 296                                 ERR("malloc returned NULL");
 297                                 return -1;
 298                         }
 299
 300                         newconn->fd = newfd;
 301
 302                         list_add(&newconn->list, &server->connections);
 303                 }
 304
 305                 for(idx=1; idx<n_fds; idx++) {
 306                         if(fds[idx].revents) {
 307                                 retval = recv_message_fd(fds[idx].fd, msg, src);
 308                                 if(**msg == 0) {
 309                                         /* connection finished */
 310                                         close(fds[idx].fd);
 311
 312                                         list_for_each_entry(conn, &server->connections, list) {
 313                                                 if(conn->fd == fds[idx].fd) {
 314                                                         list_del(&conn->list);
 315                                                         break;
 316                                                 }
 317                                         }
 318                                 }
 319                                 else {
 320                                         goto free_fds_return;
 321                                 }
 322                         }
 323                 }
 324
 325                 free(fds);
 326         }
 327
 328 free_fds_return:
 329         free(fds);
 330         return retval;
 331 }
 332
 333 int ustcomm_ustd_recv_message(struct ustcomm_ustd *ustd, char **msg, struct ustcomm_source *src, int timeout)
 334 {
 335         return ustcomm_recv_message(&ustd->server, msg, src, timeout);
 336 }
 337
 338 int ustcomm_app_recv_message(struct ustcomm_app *app, char **msg, struct ustcomm_source *src, int timeout)
 339 {
 340         return ustcomm_recv_message(&app->server, msg, src, timeout);
 341 }
 342
 343 /* This removes src from the list of active connections of app.
 344  */
 345
 346 int ustcomm_app_detach_client(struct ustcomm_app *app, struct ustcomm_source *src)
 347 {
 348         struct ustcomm_server *server = (struct ustcomm_server *)app;
 349         struct ustcomm_connection *conn;
 350
 351         list_for_each_entry(conn, &server->connections, list) {
 352                 if(conn->fd == src->fd) {
 353                         list_del(&conn->list);
 354                         goto found;
 355                 }
 356         }
 357
 358         return -1;
 359 found:
 360         return src->fd;
 361 }
 362
 363 static int init_named_socket(char *name, char **path_out)
 364 {
 365         int result;
 366         int fd;
 367
 368         struct sockaddr_un addr;
 369
 370         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 371         if(result == -1) {
 372                 PERROR("socket");
 373                 return -1;
 374         }
 375
 376         addr.sun_family = AF_UNIX;
 377
 378         strncpy(addr.sun_path, name, UNIX_PATH_MAX);
 379         addr.sun_path[UNIX_PATH_MAX-1] = '\0';
 380
 381         result = access(name, F_OK);
 382         if(result == 0) {
 383                 /* file exists */
 384                 result = unlink(name);
 385                 if(result == -1) {
 386                         PERROR("unlink of socket file");
 387                         goto close_sock;
 388                 }
 389                 WARN("socket already exists; overwriting");
 390         }
 391
 392         result = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
 393         if(result == -1) {
 394                 PERROR("bind");
 395                 goto close_sock;
 396         }
 397
 398         result = listen(fd, 1);
 399         if(result == -1) {
 400                 PERROR("listen");
 401                 goto close_sock;
 402         }
 403
 404         if(path_out) {
 405                 *path_out = "";
 406                 *path_out = strdupa(addr.sun_path);
 407         }
 408
 409         return fd;
 410
 411         close_sock:
 412         close(fd);
 413
 414         return -1;
 415 }
 416
 417 int ustcomm_send_request(struct ustcomm_connection *conn, char *req, char **reply)
 418 {
 419         int result;
 420
 421         result = send(conn->fd, req, strlen(req), 0);
 422         if(result == -1) {
 423                 PERROR("send");
 424                 return -1;
 425         }
 426
 427         if(!reply)
 428                 return 1;
 429
 430         *reply = (char *) malloc(MSG_MAX+1);
 431         result = recv(conn->fd, *reply, MSG_MAX, 0);
 432         if(result == -1) {
 433                 PERROR("recv");
 434                 return -1;
 435         }
 436         else if(result == 0) {
 437                 return 0;
 438         }
 439
 440         (*reply)[result] = '\0';
 441
 442         return 1;
 443 }
 444
 445 int ustcomm_connect_path(char *path, struct ustcomm_connection *conn, pid_t signalpid)
 446 {
 447         int fd;
 448         int result;
 449         struct sockaddr_un addr;
 450
 451         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 452         if(result == -1) {
 453                 PERROR("socket");
 454                 return -1;
 455         }
 456
 457         addr.sun_family = AF_UNIX;
 458
 459         result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s", path);
 460         if(result >= UNIX_PATH_MAX) {
 461                 ERR("string overflow allocating socket name");
 462                 return -1;
 463         }
 464
 465         if(signalpid >= 0) {
 466                 result = signal_process(signalpid);
 467                 if(result == -1) {
 468                         ERR("could not signal process");
 469                         return -1;
 470                 }
 471         }
 472
 473         result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
 474         if(result == -1) {
 475                 PERROR("connect");
 476                 return -1;
 477         }
 478
 479         conn->fd = fd;
 480
 481         return 0;
 482 }
 483
 484 int ustcomm_disconnect(struct ustcomm_connection *conn)
 485 {
 486         return close(conn->fd);
 487 }
 488
 489 int ustcomm_connect_app(pid_t pid, struct ustcomm_connection *conn)
 490 {
 491         int result;
 492         char path[UNIX_PATH_MAX];
 493
 494
 495         result = snprintf(path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
 496         if(result >= UNIX_PATH_MAX) {
 497                 fprintf(stderr, "string overflow allocating socket name");
 498                 return -1;
 499         }
 500
 501         return ustcomm_connect_path(path, conn, pid);
 502 }
 503
 504 int ustcomm_disconnect_app(struct ustcomm_connection *conn)
 505 {
 506         close(conn->fd);
 507         return 0;
 508 }
 509
 510 int ustcomm_init_app(pid_t pid, struct ustcomm_app *handle)
 511 {
 512         int result;
 513         char *name;
 514
 515         result = asprintf(&name, "%s/%d", SOCK_DIR, (int)pid);
 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 int ustcomm_init_ustd(struct ustcomm_ustd *handle)
 538 {
 539         int result;
 540         char *name;
 541
 542         result = asprintf(&name, "%s/%s", SOCK_DIR, "ustd");
 543         if(result >= UNIX_PATH_MAX) {
 544                 ERR("string overflow allocating socket name");
 545                 return -1;
 546         }
 547
 548         handle->server.listen_fd = init_named_socket(name, &handle->server.socketpath);
 549         if(handle->server.listen_fd < 0) {
 550                 ERR("error initializing named socket at %s", name);
 551                 goto free_name;
 552         }
 553         free(name);
 554
 555         INIT_LIST_HEAD(&handle->server.connections);
 556
 557         return 0;
 558
 559 free_name:
 560         free(name);
 561         return -1;
 562 }
 563
 564 static char *find_tok(char *str)
 565 {
 566         while(*str == ' ') {
 567                 str++;
 568
 569                 if(*str == 0)
 570                         return NULL;
 571         }
 572
 573         return str;
 574 }
 575
 576 static char *find_sep(char *str)
 577 {
 578         while(*str != ' ') {
 579                 str++;
 580
 581                 if(*str == 0)
 582                         break;
 583         }
 584
 585         return str;
 586 }
 587
 588 int nth_token_is(char *str, char *token, int tok_no)
 589 {
 590         int i;
 591         char *start;
 592         char *end;
 593
 594         for(i=0; i<=tok_no; i++) {
 595                 str = find_tok(str);
 596                 if(str == NULL)
 597                         return -1;
 598
 599                 start = str;
 600
 601                 str = find_sep(str);
 602                 if(str == NULL)
 603                         return -1;
 604
 605                 end = str;
 606         }
 607
 608         if(end-start != strlen(token))
 609                 return 0;
 610
 611         if(strncmp(start, token, end-start))
 612                 return 0;
 613
 614         return 1;
 615 }
 616
 617 char *nth_token(char *str, int tok_no)
 618 {
 619         static char *retval = NULL;
 620         int i;
 621         char *start;
 622         char *end;
 623
 624         for(i=0; i<=tok_no; i++) {
 625                 str = find_tok(str);
 626                 if(str == NULL)
 627                         return NULL;
 628
 629                 start = str;
 630
 631                 str = find_sep(str);
 632                 if(str == NULL)
 633                         return NULL;
 634
 635                 end = str;
 636         }
 637
 638         if(retval) {
 639                 free(retval);
 640                 retval = NULL;
 641         }
 642
 643         asprintf(&retval, "%.*s", (int)(end-start), start);
 644
 645         return retval;
 646 }
 647