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 int send_message_fd(int fd, const char *msg, char **reply)
  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         if(!reply)
  79                 return 1;
  80
  81         *reply = (char *) malloc(MSG_MAX+1);
  82         result = recv(fd, *reply, MSG_MAX, 0);
  83         if(result == -1) {
  84                 PERROR("recv");
  85                 return -1;
  86         }
  87         else if(result == 0) {
  88                 return 0;
  89         }
  90
  91         (*reply)[result] = '\0';
  92
  93         return 1;
  94 }
  95
  96 int send_message_path(const char *path, const char *msg, char **reply, int signalpid)
  97 {
  98         int fd;
  99         int result;
 100         struct sockaddr_un addr;
 101
 102         result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
 103         if(result == -1) {
 104                 PERROR("socket");
 105                 return -1;
 106         }
 107
 108         addr.sun_family = AF_UNIX;
 109
 110         result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s", path);
 111         if(result >= UNIX_PATH_MAX) {
 112                 ERR("string overflow allocating socket name");
 113                 return -1;
 114         }
 115
 116         if(signalpid >= 0)
 117                 signal_process(signalpid);
 118
 119         result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
 120         if(result == -1) {
 121                 PERROR("connect");
 122                 return -1;
 123         }
 124
 125         return send_message_fd(fd, msg, reply);
 126 }
 127
 128 /* pid: the pid of the trace process that must receive the msg
 129    msg: pointer to a null-terminated message to send
 130    reply: location where to put the null-terminated string of the reply;
 131           it must be free'd after usage
 132  */
 133
 134 int send_message(pid_t pid, const char *msg, char **reply)
 135 {
 136         int result;
 137         char path[UNIX_PATH_MAX];
 138
 139         result = snprintf(path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
 140         if(result >= UNIX_PATH_MAX) {
 141                 fprintf(stderr, "string overflow allocating socket name");
 142                 return -1;
 143         }
 144
 145         send_message_path(path, msg, reply, pid);
 146
 147         return 0;
 148 }
 149
 150 /* Called by an app to ask the consumer daemon to connect to it. */
 151
 152 int ustcomm_request_consumer(pid_t pid, const char *channel)
 153 {
 154         char path[UNIX_PATH_MAX];
 155         int result;
 156         char *msg;
 157
 158         result = snprintf(path, UNIX_PATH_MAX, "%s/ustd", SOCK_DIR);
 159         if(result >= UNIX_PATH_MAX) {
 160                 fprintf(stderr, "string overflow allocating socket name");
 161                 return -1;
 162         }
 163
 164         asprintf(&msg, "collect %d %s", pid, channel);
 165
 166         send_message_path(path, msg, NULL, -1);
 167         free(msg);
 168
 169         return 0;
 170 }
 171
 172 /* returns 1 to indicate a message was received
 173  * returns 0 to indicate no message was received (cannot happen)
 174  * returns -1 to indicate an error
 175  */
 176
 177 static int recv_message_fd(int fd, char **msg, struct ustcomm_source *src)
 178 {
 179         int result;
 180
 181         *msg = (char *) malloc(MSG_MAX+1);
 182
 183         result = recv(fd, *msg, MSG_MAX, 0);
 184         if(result == -1) {
 185                 PERROR("recv");
 186                 return -1;
 187         }
 188
 189         (*msg)[result] = '\0';
 190
 191         DBG("ustcomm_app_recv_message: result is %d, message is %s", result, (*msg));
 192
 193         if(src)
 194                 src->fd = fd;
 195
 196         return 1;
 197 }
 198
 199 int ustcomm_send_reply(struct ustcomm_server *server, char *msg, struct ustcomm_source *src)
 200 {
 201         int result;
 202
 203         result = send_message_fd(src->fd, msg, NULL);
 204         if(result) {
 205                 ERR("error in send_message_fd");
 206                 return -1;
 207         }
 208
 209         return 0;
 210 }
 211
 212 /* @timeout: max blocking time in milliseconds, -1 means infinity
 213  *
 214  * returns 1 to indicate a message was received
 215  * returns 0 to indicate no message was received
 216  * returns -1 to indicate an error
 217  */
 218
 219 int ustcomm_recv_message(struct ustcomm_server *server, char **msg, struct ustcomm_source *src, int timeout)
 220 {
 221         struct pollfd *fds;
 222         struct ustcomm_connection *conn;
 223         int result;
 224         int retval;
 225
 226         for(;;) {
 227                 int idx = 0;
 228                 int n_fds = 1;
 229
 230                 list_for_each_entry(conn, &server->connections, list) {
 231                         n_fds++;
 232                 }
 233
 234                 fds = (struct pollfd *) malloc(n_fds * sizeof(struct pollfd));
 235                 if(fds == NULL) {
 236                         ERR("malloc returned NULL");
 237                         return -1;
 238                 }
 239
 240                 /* special idx 0 is for listening socket */
 241                 fds[idx].fd = server->listen_fd;
 242                 fds[idx].events = POLLIN;
 243                 idx++;
 244
 245                 list_for_each_entry(conn, &server->connections, list) {
 246                         fds[idx].fd = conn->fd;
 247                         fds[idx].events = POLLIN;
 248                         idx++;
 249                 }
 250
 251                 result = poll(fds, n_fds, timeout);
 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(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_init_app(pid_t pid, struct ustcomm_app *handle)
 394 {
 395         int result;
 396         char *name;
 397
 398         result = asprintf(&name, "%s/%d", SOCK_DIR, (int)pid);
 399         if(result >= UNIX_PATH_MAX) {
 400                 ERR("string overflow allocating socket name");
 401                 return -1;
 402         }
 403
 404         handle->server.listen_fd = init_named_socket(name, &(handle->server.socketpath));
 405         if(handle->server.listen_fd < 0) {
 406                 ERR("error initializing named socket");
 407                 goto free_name;
 408         }
 409         free(name);
 410
 411         INIT_LIST_HEAD(&handle->server.connections);
 412
 413         return 0;
 414
 415 free_name:
 416         free(name);
 417         return -1;
 418 }
 419
 420 int ustcomm_init_ustd(struct ustcomm_ustd *handle)
 421 {
 422         int result;
 423         char *name;
 424
 425         result = asprintf(&name, "%s/%s", SOCK_DIR, "ustd");
 426         if(result >= UNIX_PATH_MAX) {
 427                 ERR("string overflow allocating socket name");
 428                 return -1;
 429         }
 430
 431         handle->server.listen_fd = init_named_socket(name, &handle->server.socketpath);
 432         if(handle->server.listen_fd < 0) {
 433                 ERR("error initializing named socket");
 434                 goto free_name;
 435         }
 436         free(name);
 437
 438         INIT_LIST_HEAD(&handle->server.connections);
 439
 440         return 0;
 441
 442 free_name:
 443         free(name);
 444         return -1;
 445 }
 446
 447 static char *find_tok(char *str)
 448 {
 449         while(*str == ' ') {
 450                 str++;
 451
 452                 if(*str == 0)
 453                         return NULL;
 454         }
 455
 456         return str;
 457 }
 458
 459 static char *find_sep(char *str)
 460 {
 461         while(*str != ' ') {
 462                 str++;
 463
 464                 if(*str == 0)
 465                         break;
 466         }
 467
 468         return str;
 469 }
 470
 471 int nth_token_is(char *str, char *token, int tok_no)
 472 {
 473         int i;
 474         char *start;
 475         char *end;
 476
 477         for(i=0; i<=tok_no; i++) {
 478                 str = find_tok(str);
 479                 if(str == NULL)
 480                         return -1;
 481
 482                 start = str;
 483
 484                 str = find_sep(str);
 485                 if(str == NULL)
 486                         return -1;
 487
 488                 end = str;
 489         }
 490
 491         if(end-start != strlen(token))
 492                 return 0;
 493
 494         if(strncmp(start, token, end-start))
 495                 return 0;
 496
 497         return 1;
 498 }
 499
 500 char *nth_token(char *str, int tok_no)
 501 {
 502         static char *retval = NULL;
 503         int i;
 504         char *start;
 505         char *end;
 506
 507         for(i=0; i<=tok_no; i++) {
 508                 str = find_tok(str);
 509                 if(str == NULL)
 510                         return NULL;
 511
 512                 start = str;
 513
 514                 str = find_sep(str);
 515                 if(str == NULL)
 516                         return NULL;
 517
 518                 end = str;
 519         }
 520
 521         if(retval) {
 522                 free(retval);
 523                 retval = NULL;
 524         }
 525
 526         asprintf(&retval, "%.*s", (int)(end-start), start);
 527
 528         return retval;
 529 }
 530