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                 while((result = poll(fds, n_fds, timeout)) == -1 && errno == EINTR)
 276                         /* nothing */;
 277                 if(result == -1) {
 278                         PERROR("poll");
 279                         return -1;
 280                 }
 281
 282                 if(result == 0)
 283                         return 0;
 284
 285                 if(fds[0].revents) {
 286                         struct ustcomm_connection *newconn;
 287                         int newfd;
 288
 289                         result = newfd = accept(server->listen_fd, NULL, NULL);
 290                         if(result == -1) {
 291                                 PERROR("accept");
 292                                 return -1;
 293                         }
 294
 295                         newconn = (struct ustcomm_connection *) malloc(sizeof(struct ustcomm_connection));
 296                         if(newconn == NULL) {
 297                                 ERR("malloc returned NULL");
 298                                 return -1;
 299                         }
 300
 301                         newconn->fd = newfd;
 302
 303                         list_add(&newconn->list, &server->connections);
 304                 }
 305
 306                 for(idx=1; idx<n_fds; idx++) {
 307                         if(fds[idx].revents) {
 308                                 retval = recv_message_fd(fds[idx].fd, msg, src);
 309                                 if(**msg == 0) {
 310                                         /* connection finished */
 311                                         close(fds[idx].fd);
 312
 313                                         list_for_each_entry(conn, &server->connections, list) {
 314                                                 if(conn->fd == fds[idx].fd) {
 315                                                         list_del(&conn->list);
 316                                                         break;
 317                                                 }
 318                                         }
 319                                 }
 320                                 else {
 321                                         goto free_fds_return;
 322                                 }
 323                         }
 324                 }
 325
 326                 free(fds);
 327         }
 328
 329 free_fds_return:
 330         free(fds);
 331         return retval;
 332 }
 333
 334 int ustcomm_ustd_recv_message(struct ustcomm_ustd *ustd, char **msg, struct ustcomm_source *src, int timeout)
 335 {
 336         return ustcomm_recv_message(&ustd->server, msg, src, timeout);
 337 }
 338
 339 int ustcomm_app_recv_message(struct ustcomm_app *app, char **msg, struct ustcomm_source *src, int timeout)
 340 {
 341         return ustcomm_recv_message(&app->server, msg, src, timeout);
 342 }
 343
 344 /* This removes src from the list of active connections of app.
 345  */
 346
 347 int ustcomm_app_detach_client(struct ustcomm_app *app, struct ustcomm_source *src)
 348 {
 349         struct ustcomm_server *server = (struct ustcomm_server *)app;
 350         struct ustcomm_connection *conn;
 351
 352         list_for_each_entry(conn, &server->connections, list) {
 353                 if(conn->fd == src->fd) {
 354                         list_del(&conn->list);
 355                         goto found;
 356                 }
 357         }
 358
 359         return -1;
 360 found:
 361         return src->fd;
 362 }
 363
 364 static int init_named_socket(char *name, char **path_out)
 365 {
 366         int result;
 367         int fd;
 368
 369         struct sockaddr_un addr;
 370
 371         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 372         if(result == -1) {
 373                 PERROR("socket");
 374                 return -1;
 375         }
 376
 377         addr.sun_family = AF_UNIX;
 378
 379         strncpy(addr.sun_path, name, UNIX_PATH_MAX);
 380         addr.sun_path[UNIX_PATH_MAX-1] = '\0';
 381
 382         result = access(name, F_OK);
 383         if(result == 0) {
 384                 /* file exists */
 385                 result = unlink(name);
 386                 if(result == -1) {
 387                         PERROR("unlink of socket file");
 388                         goto close_sock;
 389                 }
 390                 WARN("socket already exists; overwriting");
 391         }
 392
 393         result = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
 394         if(result == -1) {
 395                 PERROR("bind");
 396                 goto close_sock;
 397         }
 398
 399         result = listen(fd, 1);
 400         if(result == -1) {
 401                 PERROR("listen");
 402                 goto close_sock;
 403         }
 404
 405         if(path_out) {
 406                 *path_out = "";
 407                 *path_out = strdupa(addr.sun_path);
 408         }
 409
 410         return fd;
 411
 412         close_sock:
 413         close(fd);
 414
 415         return -1;
 416 }
 417
 418 int ustcomm_send_request(struct ustcomm_connection *conn, char *req, char **reply)
 419 {
 420         int result;
 421
 422         result = send(conn->fd, req, strlen(req), 0);
 423         if(result == -1) {
 424                 PERROR("send");
 425                 return -1;
 426         }
 427
 428         if(!reply)
 429                 return 1;
 430
 431         *reply = (char *) malloc(MSG_MAX+1);
 432         result = recv(conn->fd, *reply, MSG_MAX, 0);
 433         if(result == -1) {
 434                 PERROR("recv");
 435                 return -1;
 436         }
 437         else if(result == 0) {
 438                 return 0;
 439         }
 440
 441         (*reply)[result] = '\0';
 442
 443         return 1;
 444 }
 445
 446 int ustcomm_connect_path(char *path, struct ustcomm_connection *conn, pid_t signalpid)
 447 {
 448         int fd;
 449         int result;
 450         struct sockaddr_un addr;
 451
 452         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 453         if(result == -1) {
 454                 PERROR("socket");
 455                 return -1;
 456         }
 457
 458         addr.sun_family = AF_UNIX;
 459
 460         result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s", path);
 461         if(result >= UNIX_PATH_MAX) {
 462                 ERR("string overflow allocating socket name");
 463                 return -1;
 464         }
 465
 466         if(signalpid >= 0) {
 467                 result = signal_process(signalpid);
 468                 if(result == -1) {
 469                         ERR("could not signal process");
 470                         return -1;
 471                 }
 472         }
 473
 474         result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
 475         if(result == -1) {
 476                 PERROR("connect");
 477                 return -1;
 478         }
 479
 480         conn->fd = fd;
 481
 482         return 0;
 483 }
 484
 485 int ustcomm_disconnect(struct ustcomm_connection *conn)
 486 {
 487         return close(conn->fd);
 488 }
 489
 490 int ustcomm_connect_app(pid_t pid, struct ustcomm_connection *conn)
 491 {
 492         int result;
 493         char path[UNIX_PATH_MAX];
 494
 495
 496         result = snprintf(path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
 497         if(result >= UNIX_PATH_MAX) {
 498                 fprintf(stderr, "string overflow allocating socket name");
 499                 return -1;
 500         }
 501
 502         return ustcomm_connect_path(path, conn, pid);
 503 }
 504
 505 int ustcomm_disconnect_app(struct ustcomm_connection *conn)
 506 {
 507         close(conn->fd);
 508         return 0;
 509 }
 510
 511 int ustcomm_init_app(pid_t pid, struct ustcomm_app *handle)
 512 {
 513         int result;
 514         char *name;
 515
 516         result = asprintf(&name, "%s/%d", SOCK_DIR, (int)pid);
 517         if(result >= UNIX_PATH_MAX) {
 518                 ERR("string overflow allocating socket name");
 519                 return -1;
 520         }
 521
 522         handle->server.listen_fd = init_named_socket(name, &(handle->server.socketpath));
 523         if(handle->server.listen_fd < 0) {
 524                 ERR("error initializing named socket");
 525                 goto free_name;
 526         }
 527         free(name);
 528
 529         INIT_LIST_HEAD(&handle->server.connections);
 530
 531         return 0;
 532
 533 free_name:
 534         free(name);
 535         return -1;
 536 }
 537
 538 int ustcomm_init_ustd(struct ustcomm_ustd *handle)
 539 {
 540         int result;
 541         char *name;
 542
 543         result = asprintf(&name, "%s/%s", SOCK_DIR, "ustd");
 544         if(result >= UNIX_PATH_MAX) {
 545                 ERR("string overflow allocating socket name");
 546                 return -1;
 547         }
 548
 549         handle->server.listen_fd = init_named_socket(name, &handle->server.socketpath);
 550         if(handle->server.listen_fd < 0) {
 551                 ERR("error initializing named socket at %s", name);
 552                 goto free_name;
 553         }
 554         free(name);
 555
 556         INIT_LIST_HEAD(&handle->server.connections);
 557
 558         return 0;
 559
 560 free_name:
 561         free(name);
 562         return -1;
 563 }
 564
 565 static char *find_tok(char *str)
 566 {
 567         while(*str == ' ') {
 568                 str++;
 569
 570                 if(*str == 0)
 571                         return NULL;
 572         }
 573
 574         return str;
 575 }
 576
 577 static char *find_sep(char *str)
 578 {
 579         while(*str != ' ') {
 580                 str++;
 581
 582                 if(*str == 0)
 583                         break;
 584         }
 585
 586         return str;
 587 }
 588
 589 int nth_token_is(char *str, char *token, int tok_no)
 590 {
 591         int i;
 592         char *start;
 593         char *end;
 594
 595         for(i=0; i<=tok_no; i++) {
 596                 str = find_tok(str);
 597                 if(str == NULL)
 598                         return -1;
 599
 600                 start = str;
 601
 602                 str = find_sep(str);
 603                 if(str == NULL)
 604                         return -1;
 605
 606                 end = str;
 607         }
 608
 609         if(end-start != strlen(token))
 610                 return 0;
 611
 612         if(strncmp(start, token, end-start))
 613                 return 0;
 614
 615         return 1;
 616 }
 617
 618 char *nth_token(char *str, int tok_no)
 619 {
 620         static char *retval = NULL;
 621         int i;
 622         char *start;
 623         char *end;
 624
 625         for(i=0; i<=tok_no; i++) {
 626                 str = find_tok(str);
 627                 if(str == NULL)
 628                         return NULL;
 629
 630                 start = str;
 631
 632                 str = find_sep(str);
 633                 if(str == NULL)
 634                         return NULL;
 635
 636                 end = str;
 637         }
 638
 639         if(retval) {
 640                 free(retval);
 641                 retval = NULL;
 642         }
 643
 644         asprintf(&retval, "%.*s", (int)(end-start), start);
 645
 646         return retval;
 647 }
 648