liblttng-ust-comm/lttng-ust-comm.c

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   5  * Copyright (C) 2011-2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  */
   7
   8 #include <limits.h>
   9 #include <stdint.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/socket.h>
  14 #include <sys/stat.h>
  15 #include <sys/types.h>
  16 #include <sys/un.h>
  17 #include <unistd.h>
  18 #include <assert.h>
  19 #include <errno.h>
  20 #include <fcntl.h>
  21
  22 #include <lttng/ust-ctl.h>
  23 #include <ust-comm.h>
  24 #include <ust-fd.h>
  25 #include <ust-helper.h>
  26 #include <lttng/ust-error.h>
  27 #include <ust-dynamic-type.h>
  28 #include <usterr-signal-safe.h>
  29
  30 #include "../liblttng-ust/ust-events-internal.h"
  31 #include "../liblttng-ust/compat.h"
  32
  33 #define USTCOMM_CODE_OFFSET(code)       \
  34         (code == LTTNG_UST_OK ? 0 : (code - LTTNG_UST_ERR + 1))
  35
  36 #define USTCOMM_MAX_SEND_FDS    4
  37
  38 static
  39 ssize_t count_fields_recursive(size_t nr_fields,
  40                 const struct lttng_event_field *lttng_fields);
  41 static
  42 int serialize_one_field(struct lttng_session *session,
  43                 struct ustctl_field *fields, size_t *iter_output,
  44                 const struct lttng_event_field *lf);
  45 static
  46 int serialize_fields(struct lttng_session *session,
  47                 struct ustctl_field *ustctl_fields,
  48                 size_t *iter_output, size_t nr_lttng_fields,
  49                 const struct lttng_event_field *lttng_fields);
  50
  51 /*
  52  * Human readable error message.
  53  */
  54 static const char *ustcomm_readable_code[] = {
  55         [ USTCOMM_CODE_OFFSET(LTTNG_UST_OK) ] = "Success",
  56         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR) ] = "Unknown error",
  57         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_NOENT) ] = "No entry",
  58         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_EXIST) ] = "Object already exists",
  59         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL) ] = "Invalid argument",
  60         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_PERM) ] = "Permission denied",
  61         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_NOSYS) ] = "Not implemented",
  62         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_EXITING) ] = "Process is exiting",
  63
  64         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL_MAGIC) ] = "Invalid magic number",
  65         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL_SOCKET_TYPE) ] = "Invalid socket type",
  66         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_UNSUP_MAJOR) ] = "Unsupported major version",
  67         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_PEERCRED) ] = "Cannot get unix socket peer credentials",
  68         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_PEERCRED_PID) ] = "Peer credentials PID is invalid. Socket appears to belong to a distinct, non-nested pid namespace.",
  69 };
  70
  71 /*
  72  * lttng_ust_strerror
  73  *
  74  * Receives positive error value.
  75  * Return ptr to string representing a human readable
  76  * error code from the ustcomm_return_code enum.
  77  */
  78 const char *lttng_ust_strerror(int code)
  79 {
  80         if (code == LTTNG_UST_OK)
  81                 return ustcomm_readable_code[USTCOMM_CODE_OFFSET(code)];
  82         if (code < LTTNG_UST_ERR)
  83                 return strerror(code);
  84         if (code >= LTTNG_UST_ERR_NR)
  85                 code = LTTNG_UST_ERR;
  86         return ustcomm_readable_code[USTCOMM_CODE_OFFSET(code)];
  87 }
  88
  89 /*
  90  * ustcomm_connect_unix_sock
  91  *
  92  * Connect to unix socket using the path name.
  93  *
  94  * Caller handles FD tracker.
  95  */
  96 int ustcomm_connect_unix_sock(const char *pathname, long timeout)
  97 {
  98         struct sockaddr_un sun;
  99         int fd, ret;
 100
 101         /*
 102          * libust threads require the close-on-exec flag for all
 103          * resources so it does not leak file descriptors upon exec.
 104          * SOCK_CLOEXEC is not used since it is linux specific.
 105          */
 106         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 107         if (fd < 0) {
 108                 PERROR("socket");
 109                 ret = -errno;
 110                 goto error;
 111         }
 112         if (timeout >= 0) {
 113                 /* Give at least 10ms. */
 114                 if (timeout < 10)
 115                         timeout = 10;
 116                 ret = ustcomm_setsockopt_snd_timeout(fd, timeout);
 117                 if (ret < 0) {
 118                         WARN("Error setting connect socket send timeout");
 119                 }
 120         }
 121         ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
 122         if (ret < 0) {
 123                 PERROR("fcntl");
 124                 ret = -errno;
 125                 goto error_fcntl;
 126         }
 127
 128         memset(&sun, 0, sizeof(sun));
 129         sun.sun_family = AF_UNIX;
 130         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 131         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 132
 133         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 134         if (ret < 0) {
 135                 /*
 136                  * Don't print message on connect ENOENT error, because
 137                  * connect is used in normal execution to detect if
 138                  * sessiond is alive. ENOENT is when the unix socket
 139                  * file does not exist, and ECONNREFUSED is when the
 140                  * file exists but no sessiond is listening.
 141                  */
 142                 if (errno != ECONNREFUSED && errno != ECONNRESET
 143                                 && errno != ENOENT && errno != EACCES)
 144                         PERROR("connect");
 145                 ret = -errno;
 146                 if (ret == -ECONNREFUSED || ret == -ECONNRESET)
 147                         ret = -EPIPE;
 148                 goto error_connect;
 149         }
 150
 151         return fd;
 152
 153 error_connect:
 154 error_fcntl:
 155         {
 156                 int closeret;
 157
 158                 closeret = close(fd);
 159                 if (closeret)
 160                         PERROR("close");
 161         }
 162 error:
 163         return ret;
 164 }
 165
 166 /*
 167  * ustcomm_accept_unix_sock
 168  *
 169  * Do an accept(2) on the sock and return the
 170  * new file descriptor. The socket MUST be bind(2) before.
 171  */
 172 int ustcomm_accept_unix_sock(int sock)
 173 {
 174         int new_fd;
 175         struct sockaddr_un sun;
 176         socklen_t len = 0;
 177
 178         /* Blocking call */
 179         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 180         if (new_fd < 0) {
 181                 if (errno != ECONNABORTED)
 182                         PERROR("accept");
 183                 new_fd = -errno;
 184                 if (new_fd == -ECONNABORTED)
 185                         new_fd = -EPIPE;
 186         }
 187         return new_fd;
 188 }
 189
 190 /*
 191  * ustcomm_create_unix_sock
 192  *
 193  * Creates a AF_UNIX local socket using pathname
 194  * bind the socket upon creation and return the fd.
 195  */
 196 int ustcomm_create_unix_sock(const char *pathname)
 197 {
 198         struct sockaddr_un sun;
 199         int fd, ret;
 200
 201         /* Create server socket */
 202         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 203                 PERROR("socket");
 204                 ret = -errno;
 205                 goto error;
 206         }
 207
 208         memset(&sun, 0, sizeof(sun));
 209         sun.sun_family = AF_UNIX;
 210         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 211         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 212
 213         /* Unlink the old file if present */
 214         (void) unlink(pathname);
 215         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 216         if (ret < 0) {
 217                 PERROR("bind");
 218                 ret = -errno;
 219                 goto error_close;
 220         }
 221
 222         return fd;
 223
 224 error_close:
 225         {
 226                 int closeret;
 227
 228                 closeret = close(fd);
 229                 if (closeret) {
 230                         PERROR("close");
 231                 }
 232         }
 233 error:
 234         return ret;
 235 }
 236
 237 /*
 238  * ustcomm_listen_unix_sock
 239  *
 240  * Make the socket listen using LTTNG_UST_COMM_MAX_LISTEN.
 241  */
 242 int ustcomm_listen_unix_sock(int sock)
 243 {
 244         int ret;
 245
 246         ret = listen(sock, LTTNG_UST_COMM_MAX_LISTEN);
 247         if (ret < 0) {
 248                 ret = -errno;
 249                 PERROR("listen");
 250         }
 251
 252         return ret;
 253 }
 254
 255 /*
 256  * ustcomm_close_unix_sock
 257  *
 258  * Shutdown cleanly a unix socket.
 259  *
 260  * Handles fd tracker internally.
 261  */
 262 int ustcomm_close_unix_sock(int sock)
 263 {
 264         int ret;
 265
 266         lttng_ust_lock_fd_tracker();
 267         ret = close(sock);
 268         if (!ret) {
 269                 lttng_ust_delete_fd_from_tracker(sock);
 270         } else {
 271                 PERROR("close");
 272                 ret = -errno;
 273         }
 274         lttng_ust_unlock_fd_tracker();
 275
 276         return ret;
 277 }
 278
 279 /*
 280  * ustcomm_recv_unix_sock
 281  *
 282  * Receive data of size len in put that data into
 283  * the buf param. Using recvmsg API.
 284  * Return the size of received data.
 285  * Return 0 on orderly shutdown.
 286  */
 287 ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len)
 288 {
 289         struct msghdr msg;
 290         struct iovec iov[1];
 291         ssize_t ret = -1;
 292         size_t len_last;
 293
 294         memset(&msg, 0, sizeof(msg));
 295
 296         iov[0].iov_base = buf;
 297         iov[0].iov_len = len;
 298         msg.msg_iov = iov;
 299         msg.msg_iovlen = 1;
 300
 301         do {
 302                 len_last = iov[0].iov_len;
 303                 ret = recvmsg(sock, &msg, 0);
 304                 if (ret > 0) {
 305                         iov[0].iov_base += ret;
 306                         iov[0].iov_len -= ret;
 307                         assert(ret <= len_last);
 308                 }
 309         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 310
 311         if (ret < 0) {
 312                 int shutret;
 313
 314                 if (errno != EPIPE && errno != ECONNRESET && errno != ECONNREFUSED)
 315                         PERROR("recvmsg");
 316                 ret = -errno;
 317                 if (ret == -ECONNRESET || ret == -ECONNREFUSED)
 318                         ret = -EPIPE;
 319
 320                 shutret = shutdown(sock, SHUT_RDWR);
 321                 if (shutret)
 322                         ERR("Socket shutdown error");
 323         } else if (ret > 0) {
 324                 ret = len;
 325         }
 326         /* ret = 0 means an orderly shutdown. */
 327
 328         return ret;
 329 }
 330
 331 /*
 332  * ustcomm_send_unix_sock
 333  *
 334  * Send buf data of size len. Using sendmsg API.
 335  * Return the size of sent data.
 336  */
 337 ssize_t ustcomm_send_unix_sock(int sock, const void *buf, size_t len)
 338 {
 339         struct msghdr msg;
 340         struct iovec iov[1];
 341         ssize_t ret;
 342
 343         memset(&msg, 0, sizeof(msg));
 344
 345         iov[0].iov_base = (void *) buf;
 346         iov[0].iov_len = len;
 347         msg.msg_iov = iov;
 348         msg.msg_iovlen = 1;
 349
 350         /*
 351          * Using the MSG_NOSIGNAL when sending data from sessiond to
 352          * libust, so libust does not receive an unhandled SIGPIPE or
 353          * SIGURG. The sessiond receiver side can be made more resilient
 354          * by ignoring SIGPIPE, but we don't have this luxury on the
 355          * libust side.
 356          */
 357         do {
 358                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 359         } while (ret < 0 && errno == EINTR);
 360
 361         if (ret < 0) {
 362                 int shutret;
 363
 364                 if (errno != EPIPE && errno != ECONNRESET)
 365                         PERROR("sendmsg");
 366                 ret = -errno;
 367                 if (ret == -ECONNRESET)
 368                         ret = -EPIPE;
 369
 370                 shutret = shutdown(sock, SHUT_RDWR);
 371                 if (shutret)
 372                         ERR("Socket shutdown error");
 373         }
 374
 375         return ret;
 376 }
 377
 378 /*
 379  * Send a message accompanied by fd(s) over a unix socket.
 380  *
 381  * Returns the size of data sent, or negative error value.
 382  */
 383 ssize_t ustcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 384 {
 385         struct msghdr msg;
 386         struct cmsghdr *cmptr;
 387         struct iovec iov[1];
 388         ssize_t ret = -1;
 389         unsigned int sizeof_fds = nb_fd * sizeof(int);
 390         char tmp[CMSG_SPACE(sizeof_fds)];
 391         char dummy = 0;
 392
 393         memset(&msg, 0, sizeof(msg));
 394         memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
 395
 396         if (nb_fd > USTCOMM_MAX_SEND_FDS)
 397                 return -EINVAL;
 398
 399         msg.msg_control = (caddr_t)tmp;
 400         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 401
 402         cmptr = CMSG_FIRSTHDR(&msg);
 403         if (!cmptr)
 404                 return -EINVAL;
 405         cmptr->cmsg_level = SOL_SOCKET;
 406         cmptr->cmsg_type = SCM_RIGHTS;
 407         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 408         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 409         /* Sum of the length of all control messages in the buffer: */
 410         msg.msg_controllen = cmptr->cmsg_len;
 411
 412         iov[0].iov_base = &dummy;
 413         iov[0].iov_len = 1;
 414         msg.msg_iov = iov;
 415         msg.msg_iovlen = 1;
 416
 417         do {
 418                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 419         } while (ret < 0 && errno == EINTR);
 420         if (ret < 0) {
 421                 /*
 422                  * We consider EPIPE and ECONNRESET as expected.
 423                  */
 424                 if (errno != EPIPE && errno != ECONNRESET) {
 425                         PERROR("sendmsg");
 426                 }
 427                 ret = -errno;
 428                 if (ret == -ECONNRESET)
 429                         ret = -EPIPE;
 430         }
 431         return ret;
 432 }
 433
 434 /*
 435  * Recv a message accompanied by fd(s) from a unix socket.
 436  *
 437  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 438  * actually received in nb_fd.
 439  * Returns -EPIPE on orderly shutdown.
 440  */
 441 ssize_t ustcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 442 {
 443         struct iovec iov[1];
 444         ssize_t ret = 0;
 445         struct cmsghdr *cmsg;
 446         size_t sizeof_fds = nb_fd * sizeof(int);
 447         char recv_fd[CMSG_SPACE(sizeof_fds)];
 448         struct msghdr msg;
 449         char dummy;
 450         int i;
 451
 452         memset(&msg, 0, sizeof(msg));
 453
 454         /* Prepare to receive the structures */
 455         iov[0].iov_base = &dummy;
 456         iov[0].iov_len = 1;
 457         msg.msg_iov = iov;
 458         msg.msg_iovlen = 1;
 459         msg.msg_control = recv_fd;
 460         msg.msg_controllen = sizeof(recv_fd);
 461
 462         do {
 463                 ret = recvmsg(sock, &msg, 0);
 464         } while (ret < 0 && errno == EINTR);
 465         if (ret < 0) {
 466                 if (errno != EPIPE && errno != ECONNRESET) {
 467                         PERROR("recvmsg fds");
 468                 }
 469                 ret = -errno;
 470                 if (ret == -ECONNRESET)
 471                         ret = -EPIPE;
 472                 goto end;
 473         }
 474         if (ret == 0) {
 475                 /* orderly shutdown */
 476                 ret = -EPIPE;
 477                 goto end;
 478         }
 479         if (ret != 1) {
 480                 ERR("Error: Received %zd bytes, expected %d\n",
 481                                 ret, 1);
 482                 goto end;
 483         }
 484         if (msg.msg_flags & MSG_CTRUNC) {
 485                 ERR("Error: Control message truncated.\n");
 486                 ret = -1;
 487                 goto end;
 488         }
 489         cmsg = CMSG_FIRSTHDR(&msg);
 490         if (!cmsg) {
 491                 ERR("Error: Invalid control message header\n");
 492                 ret = -1;
 493                 goto end;
 494         }
 495         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 496                 ERR("Didn't received any fd\n");
 497                 ret = -1;
 498                 goto end;
 499         }
 500         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 501                 ERR("Error: Received %zu bytes of ancillary data, expected %zu\n",
 502                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 503                 ret = -1;
 504                 goto end;
 505         }
 506
 507         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 508
 509         /* Set FD_CLOEXEC */
 510         for (i = 0; i < nb_fd; i++) {
 511                 ret = fcntl(fds[i], F_SETFD, FD_CLOEXEC);
 512                 if (ret < 0) {
 513                         PERROR("fcntl failed to set FD_CLOEXEC on fd %d",
 514                                fds[i]);
 515                 }
 516         }
 517
 518         ret = nb_fd;
 519 end:
 520         return ret;
 521 }
 522
 523 int ustcomm_send_app_msg(int sock, struct ustcomm_ust_msg *lum)
 524 {
 525         ssize_t len;
 526
 527         len = ustcomm_send_unix_sock(sock, lum, sizeof(*lum));
 528         switch (len) {
 529         case sizeof(*lum):
 530                 break;
 531         default:
 532                 if (len < 0) {
 533                         return len;
 534                 } else {
 535                         ERR("incorrect message size: %zd\n", len);
 536                         return -EINVAL;
 537                 }
 538         }
 539         return 0;
 540 }
 541
 542 int ustcomm_recv_app_reply(int sock, struct ustcomm_ust_reply *lur,
 543                           uint32_t expected_handle, uint32_t expected_cmd)
 544 {
 545         ssize_t len;
 546
 547         memset(lur, 0, sizeof(*lur));
 548         len = ustcomm_recv_unix_sock(sock, lur, sizeof(*lur));
 549         switch (len) {
 550         case 0: /* orderly shutdown */
 551                 return -EPIPE;
 552         case sizeof(*lur):
 553         {
 554                 int err = 0;
 555
 556                 if (lur->handle != expected_handle) {
 557                         ERR("Unexpected result message handle: "
 558                                 "expected: %u vs received: %u\n",
 559                                 expected_handle, lur->handle);
 560                         err = 1;
 561                 }
 562                 if (lur->cmd != expected_cmd) {
 563                         ERR("Unexpected result message command "
 564                                 "expected: %u vs received: %u\n",
 565                                 expected_cmd, lur->cmd);
 566                         err = 1;
 567                 }
 568                 if (err) {
 569                         return -EINVAL;
 570                 } else {
 571                         return lur->ret_code;
 572                 }
 573         }
 574         default:
 575                 if (len >= 0) {
 576                         ERR("incorrect message size: %zd\n", len);
 577                 }
 578                 return len;
 579         }
 580 }
 581
 582 int ustcomm_send_app_cmd(int sock,
 583                         struct ustcomm_ust_msg *lum,
 584                         struct ustcomm_ust_reply *lur)
 585 {
 586         int ret;
 587
 588         ret = ustcomm_send_app_msg(sock, lum);
 589         if (ret)
 590                 return ret;
 591         ret = ustcomm_recv_app_reply(sock, lur, lum->handle, lum->cmd);
 592         if (ret > 0)
 593                 return -EIO;
 594         return ret;
 595 }
 596
 597 /*
 598  * chan_data is allocated internally if this function returns the
 599  * expected var_len.
 600  */
 601 ssize_t ustcomm_recv_channel_from_sessiond(int sock,
 602                 void **_chan_data, uint64_t var_len,
 603                 int *_wakeup_fd)
 604 {
 605         void *chan_data;
 606         ssize_t len, nr_fd;
 607         int wakeup_fd, ret;
 608
 609         if (var_len > LTTNG_UST_CHANNEL_DATA_MAX_LEN) {
 610                 len = -EINVAL;
 611                 goto error_check;
 612         }
 613         /* Receive variable length data */
 614         chan_data = zmalloc(var_len);
 615         if (!chan_data) {
 616                 len = -ENOMEM;
 617                 goto error_alloc;
 618         }
 619         len = ustcomm_recv_unix_sock(sock, chan_data, var_len);
 620         if (len != var_len) {
 621                 goto error_recv;
 622         }
 623         /* recv wakeup fd */
 624         lttng_ust_lock_fd_tracker();
 625         nr_fd = ustcomm_recv_fds_unix_sock(sock, &wakeup_fd, 1);
 626         if (nr_fd <= 0) {
 627                 lttng_ust_unlock_fd_tracker();
 628                 if (nr_fd < 0) {
 629                         len = nr_fd;
 630                         goto error_recv;
 631                 } else {
 632                         len = -EIO;
 633                         goto error_recv;
 634                 }
 635         }
 636
 637         ret = lttng_ust_add_fd_to_tracker(wakeup_fd);
 638         if (ret < 0) {
 639                 ret = close(wakeup_fd);
 640                 if (ret) {
 641                         PERROR("close on wakeup_fd");
 642                 }
 643                 len = -EIO;
 644                 lttng_ust_unlock_fd_tracker();
 645                 goto error_recv;
 646         }
 647
 648         *_wakeup_fd = ret;
 649         lttng_ust_unlock_fd_tracker();
 650
 651         *_chan_data = chan_data;
 652         return len;
 653
 654 error_recv:
 655         free(chan_data);
 656 error_alloc:
 657 error_check:
 658         return len;
 659 }
 660
 661 ssize_t ustcomm_recv_event_notifier_notif_fd_from_sessiond(int sock,
 662                 int *_event_notifier_notif_fd)
 663 {
 664         ssize_t nr_fd;
 665         int event_notifier_notif_fd, ret;
 666
 667         /* Receive event_notifier notification fd */
 668         lttng_ust_lock_fd_tracker();
 669         nr_fd = ustcomm_recv_fds_unix_sock(sock, &event_notifier_notif_fd, 1);
 670         if (nr_fd <= 0) {
 671                 lttng_ust_unlock_fd_tracker();
 672                 if (nr_fd < 0) {
 673                         ret = nr_fd;
 674                         goto error;
 675                 } else {
 676                         ret = -EIO;
 677                         goto error;
 678                 }
 679         }
 680
 681         ret = lttng_ust_add_fd_to_tracker(event_notifier_notif_fd);
 682         if (ret < 0) {
 683                 ret = close(event_notifier_notif_fd);
 684                 if (ret) {
 685                         PERROR("close on event_notifier notif fd");
 686                 }
 687                 ret = -EIO;
 688                 lttng_ust_unlock_fd_tracker();
 689                 goto error;
 690         }
 691
 692         *_event_notifier_notif_fd = ret;
 693         lttng_ust_unlock_fd_tracker();
 694
 695         ret = nr_fd;
 696
 697 error:
 698         return ret;
 699 }
 700
 701 int ustcomm_recv_stream_from_sessiond(int sock,
 702                 uint64_t *memory_map_size,
 703                 int *shm_fd, int *wakeup_fd)
 704 {
 705         ssize_t len;
 706         int ret;
 707         int fds[2];
 708
 709         /* recv shm fd and wakeup fd */
 710         lttng_ust_lock_fd_tracker();
 711         len = ustcomm_recv_fds_unix_sock(sock, fds, 2);
 712         if (len <= 0) {
 713                 lttng_ust_unlock_fd_tracker();
 714                 if (len < 0) {
 715                         ret = len;
 716                         goto error;
 717                 } else {
 718                         ret = -EIO;
 719                         goto error;
 720                 }
 721         }
 722
 723         ret = lttng_ust_add_fd_to_tracker(fds[0]);
 724         if (ret < 0) {
 725                 ret = close(fds[0]);
 726                 if (ret) {
 727                         PERROR("close on received shm_fd");
 728                 }
 729                 ret = -EIO;
 730                 lttng_ust_unlock_fd_tracker();
 731                 goto error;
 732         }
 733         *shm_fd = ret;
 734
 735         ret = lttng_ust_add_fd_to_tracker(fds[1]);
 736         if (ret < 0) {
 737                 ret = close(*shm_fd);
 738                 if (ret) {
 739                         PERROR("close on shm_fd");
 740                 }
 741                 *shm_fd = -1;
 742                 ret = close(fds[1]);
 743                 if (ret) {
 744                         PERROR("close on received wakeup_fd");
 745                 }
 746                 ret = -EIO;
 747                 lttng_ust_unlock_fd_tracker();
 748                 goto error;
 749         }
 750         *wakeup_fd = ret;
 751         lttng_ust_unlock_fd_tracker();
 752         return 0;
 753
 754 error:
 755         return ret;
 756 }
 757
 758 ssize_t ustcomm_recv_counter_from_sessiond(int sock,
 759                 void **_counter_data, uint64_t var_len)
 760 {
 761         void *counter_data;
 762         ssize_t len;
 763
 764         if (var_len > LTTNG_UST_COUNTER_DATA_MAX_LEN) {
 765                 len = -EINVAL;
 766                 goto error_check;
 767         }
 768         /* Receive variable length data */
 769         counter_data = zmalloc(var_len);
 770         if (!counter_data) {
 771                 len = -ENOMEM;
 772                 goto error_alloc;
 773         }
 774         len = ustcomm_recv_unix_sock(sock, counter_data, var_len);
 775         if (len != var_len) {
 776                 goto error_recv;
 777         }
 778         *_counter_data = counter_data;
 779         return len;
 780
 781 error_recv:
 782         free(counter_data);
 783 error_alloc:
 784 error_check:
 785         return len;
 786 }
 787
 788 int ustcomm_recv_counter_shm_from_sessiond(int sock,
 789                 int *shm_fd)
 790 {
 791         ssize_t len;
 792         int ret;
 793         int fds[1];
 794
 795         /* recv shm fd fd */
 796         lttng_ust_lock_fd_tracker();
 797         len = ustcomm_recv_fds_unix_sock(sock, fds, 1);
 798         if (len <= 0) {
 799                 lttng_ust_unlock_fd_tracker();
 800                 if (len < 0) {
 801                         ret = len;
 802                         goto error;
 803                 } else {
 804                         ret = -EIO;
 805                         goto error;
 806                 }
 807         }
 808
 809         ret = lttng_ust_add_fd_to_tracker(fds[0]);
 810         if (ret < 0) {
 811                 ret = close(fds[0]);
 812                 if (ret) {
 813                         PERROR("close on received shm_fd");
 814                 }
 815                 ret = -EIO;
 816                 lttng_ust_unlock_fd_tracker();
 817                 goto error;
 818         }
 819         *shm_fd = ret;
 820         lttng_ust_unlock_fd_tracker();
 821         return 0;
 822
 823 error:
 824         return ret;
 825 }
 826
 827 /*
 828  * Returns 0 on success, negative error value on error.
 829  */
 830 int ustcomm_send_reg_msg(int sock,
 831                 enum ustctl_socket_type type,
 832                 uint32_t bits_per_long,
 833                 uint32_t uint8_t_alignment,
 834                 uint32_t uint16_t_alignment,
 835                 uint32_t uint32_t_alignment,
 836                 uint32_t uint64_t_alignment,
 837                 uint32_t long_alignment)
 838 {
 839         ssize_t len;
 840         struct ustctl_reg_msg reg_msg;
 841
 842         reg_msg.magic = LTTNG_UST_COMM_MAGIC;
 843         reg_msg.major = LTTNG_UST_ABI_MAJOR_VERSION;
 844         reg_msg.minor = LTTNG_UST_ABI_MINOR_VERSION;
 845         reg_msg.pid = getpid();
 846         reg_msg.ppid = getppid();
 847         reg_msg.uid = getuid();
 848         reg_msg.gid = getgid();
 849         reg_msg.bits_per_long = bits_per_long;
 850         reg_msg.uint8_t_alignment = uint8_t_alignment;
 851         reg_msg.uint16_t_alignment = uint16_t_alignment;
 852         reg_msg.uint32_t_alignment = uint32_t_alignment;
 853         reg_msg.uint64_t_alignment = uint64_t_alignment;
 854         reg_msg.long_alignment = long_alignment;
 855         reg_msg.socket_type = type;
 856         lttng_pthread_getname_np(reg_msg.name, LTTNG_UST_ABI_PROCNAME_LEN);
 857         memset(reg_msg.padding, 0, sizeof(reg_msg.padding));
 858
 859         len = ustcomm_send_unix_sock(sock, &reg_msg, sizeof(reg_msg));
 860         if (len > 0 && len != sizeof(reg_msg))
 861                 return -EIO;
 862         if (len < 0)
 863                 return len;
 864         return 0;
 865 }
 866
 867 static
 868 ssize_t count_one_type(const struct lttng_type *lt)
 869 {
 870         switch (lt->atype) {
 871         case atype_integer:
 872         case atype_float:
 873         case atype_string:
 874                 return 1;
 875         case atype_enum_nestable:
 876                 return count_one_type(lt->u.enum_nestable.container_type) + 1;
 877         case atype_array_nestable:
 878                 return count_one_type(lt->u.array_nestable.elem_type) + 1;
 879         case atype_sequence_nestable:
 880                 return count_one_type(lt->u.sequence_nestable.elem_type) + 1;
 881         case atype_struct_nestable:
 882                 return count_fields_recursive(lt->u.struct_nestable.nr_fields,
 883                                 lt->u.struct_nestable.fields) + 1;
 884
 885         case atype_dynamic:
 886         {
 887                 const struct lttng_event_field *choices;
 888                 size_t nr_choices;
 889                 int ret;
 890
 891                 ret = lttng_ust_dynamic_type_choices(&nr_choices,
 892                         &choices);
 893                 if (ret)
 894                         return ret;
 895                 /*
 896                  * Two fields for enum, one field for variant, and
 897                  * one field per choice.
 898                  */
 899                 return count_fields_recursive(nr_choices, choices) + 3;
 900         }
 901
 902         default:
 903                 return -EINVAL;
 904         }
 905         return 0;
 906 }
 907
 908 static
 909 ssize_t count_fields_recursive(size_t nr_fields,
 910                 const struct lttng_event_field *lttng_fields)
 911 {
 912         int i;
 913         ssize_t ret, count = 0;
 914
 915         for (i = 0; i < nr_fields; i++) {
 916                 const struct lttng_event_field *lf;
 917
 918                 lf = &lttng_fields[i];
 919                 /* skip 'nowrite' fields */
 920                 if (lf->nowrite)
 921                         continue;
 922                 ret = count_one_type(&lf->type);
 923                 if (ret < 0)
 924                         return ret;     /* error */
 925                 count += ret;
 926         }
 927         return count;
 928 }
 929
 930 static
 931 ssize_t count_ctx_fields_recursive(size_t nr_fields,
 932                 const struct lttng_ctx_field *lttng_fields)
 933 {
 934         int i;
 935         ssize_t ret, count = 0;
 936
 937         for (i = 0; i < nr_fields; i++) {
 938                 const struct lttng_event_field *lf;
 939
 940                 lf = &lttng_fields[i].event_field;
 941                 /* skip 'nowrite' fields */
 942                 if (lf->nowrite)
 943                         continue;
 944                 ret = count_one_type(&lf->type);
 945                 if (ret < 0)
 946                         return ret;     /* error */
 947                 count += ret;
 948         }
 949         return count;
 950 }
 951
 952 static
 953 int serialize_dynamic_type(struct lttng_session *session,
 954                 struct ustctl_field *fields, size_t *iter_output,
 955                 const char *field_name)
 956 {
 957         const struct lttng_event_field *choices;
 958         char tag_field_name[LTTNG_UST_SYM_NAME_LEN];
 959         const struct lttng_type *tag_type;
 960         const struct lttng_event_field *tag_field_generic;
 961         struct lttng_event_field tag_field = {
 962                 .name = tag_field_name,
 963                 .nowrite = 0,
 964         };
 965         struct ustctl_field *uf;
 966         size_t nr_choices, i;
 967         int ret;
 968
 969         tag_field_generic = lttng_ust_dynamic_type_tag_field();
 970         tag_type = &tag_field_generic->type;
 971
 972         /* Serialize enum field. */
 973         strncpy(tag_field_name, field_name, LTTNG_UST_SYM_NAME_LEN);
 974         tag_field_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 975         strncat(tag_field_name,
 976                 "_tag",
 977                 LTTNG_UST_SYM_NAME_LEN - strlen(tag_field_name) - 1);
 978         tag_field.type = *tag_type;
 979         ret = serialize_one_field(session, fields, iter_output,
 980                 &tag_field);
 981         if (ret)
 982                 return ret;
 983
 984         /* Serialize variant field. */
 985         uf = &fields[*iter_output];
 986         ret = lttng_ust_dynamic_type_choices(&nr_choices, &choices);
 987         if (ret)
 988                 return ret;
 989
 990         strncpy(uf->name, field_name, LTTNG_UST_SYM_NAME_LEN);
 991         uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 992         uf->type.atype = ustctl_atype_variant;
 993         uf->type.u.variant_nestable.nr_choices = nr_choices;
 994         strncpy(uf->type.u.variant_nestable.tag_name,
 995                 tag_field_name,
 996                 LTTNG_UST_SYM_NAME_LEN);
 997         uf->type.u.variant_nestable.tag_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 998         uf->type.u.variant_nestable.alignment = 0;
 999         (*iter_output)++;
1000
1001         /* Serialize choice fields after variant. */
1002         for (i = 0; i < nr_choices; i++) {
1003                 ret = serialize_one_field(session, fields,
1004                         iter_output, &choices[i]);
1005                 if (ret)
1006                         return ret;
1007         }
1008         return 0;
1009 }
1010
1011 static
1012 int serialize_one_type(struct lttng_session *session,
1013                 struct ustctl_field *fields, size_t *iter_output,
1014                 const char *field_name, const struct lttng_type *lt)
1015 {
1016         int ret;
1017
1018         /*
1019          * Serializing a type (rather than a field) generates a ustctl_field
1020          * entry with 0-length name.
1021          */
1022
1023         switch (lt->atype) {
1024         case atype_integer:
1025         case atype_float:
1026         case atype_string:
1027         case atype_array_nestable:
1028         {
1029                 struct ustctl_field *uf = &fields[*iter_output];
1030                 struct ustctl_type *ut = &uf->type;
1031
1032                 if (field_name) {
1033                         strncpy(uf->name, field_name, LTTNG_UST_SYM_NAME_LEN);
1034                         uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1035                 } else {
1036                         uf->name[0] = '\0';
1037                 }
1038                 ut->atype = ustctl_atype_array_nestable;
1039                 ut->u.array_nestable.length = lt->u.array_nestable.length;
1040                 ut->u.array_nestable.alignment = lt->u.array_nestable.alignment;
1041                 (*iter_output)++;
1042
1043                 ret = serialize_one_type(session, fields, iter_output, NULL,
1044                                 lt->u.array_nestable.elem_type);
1045                 if (ret)
1046                         return -EINVAL;
1047                 break;
1048         }
1049         case atype_sequence_nestable:
1050         {
1051                 struct ustctl_field *uf = &fields[*iter_output];
1052                 struct ustctl_type *ut = &uf->type;
1053
1054                 if (field_name) {
1055                         strncpy(uf->name, field_name, LTTNG_UST_SYM_NAME_LEN);
1056                         uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1057                 } else {
1058                         uf->name[0] = '\0';
1059                 }
1060                 ut->atype = ustctl_atype_sequence_nestable;
1061                 strncpy(ut->u.sequence_nestable.length_name,
1062                         lt->u.sequence_nestable.length_name,
1063                         LTTNG_UST_SYM_NAME_LEN);
1064                 ut->u.sequence_nestable.length_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1065                 ut->u.sequence_nestable.alignment = lt->u.sequence_nestable.alignment;
1066                 (*iter_output)++;
1067
1068                 ret = serialize_one_type(session, fields, iter_output, NULL,
1069                                 lt->u.sequence_nestable.elem_type);
1070                 if (ret)
1071                         return -EINVAL;
1072                 break;
1073         }
1074         case atype_dynamic:
1075         {
1076                 ret = serialize_dynamic_type(session, fields, iter_output,
1077                                 field_name);
1078                 if (ret)
1079                         return -EINVAL;
1080                 break;
1081         }
1082         case atype_struct_nestable:
1083         {
1084                 struct ustctl_field *uf = &fields[*iter_output];
1085
1086                 if (field_name) {
1087                         strncpy(uf->name, field_name, LTTNG_UST_SYM_NAME_LEN);
1088                         uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1089                 } else {
1090                         uf->name[0] = '\0';
1091                 }
1092                 uf->type.atype = ustctl_atype_struct_nestable;
1093                 uf->type.u.struct_nestable.nr_fields = lt->u.struct_nestable.nr_fields;
1094                 uf->type.u.struct_nestable.alignment = lt->u.struct_nestable.alignment;
1095                 (*iter_output)++;
1096
1097                 ret = serialize_fields(session, fields, iter_output,
1098                                 lt->u.struct_nestable.nr_fields,
1099                                 lt->u.struct_nestable.fields);
1100                 if (ret)
1101                         return -EINVAL;
1102                 break;
1103         }
1104         case atype_enum_nestable:
1105         {
1106                 struct ustctl_field *uf = &fields[*iter_output];
1107                 struct ustctl_type *ut = &uf->type;
1108
1109                 if (field_name) {
1110                         strncpy(uf->name, field_name, LTTNG_UST_SYM_NAME_LEN);
1111                         uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1112                 } else {
1113                         uf->name[0] = '\0';
1114                 }
1115                 strncpy(ut->u.enum_nestable.name, lt->u.enum_nestable.desc->name,
1116                                 LTTNG_UST_SYM_NAME_LEN);
1117                 ut->u.enum_nestable.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1118                 ut->atype = ustctl_atype_enum_nestable;
1119                 (*iter_output)++;
1120
1121                 ret = serialize_one_type(session, fields, iter_output, NULL,
1122                                 lt->u.enum_nestable.container_type);
1123                 if (ret)
1124                         return -EINVAL;
1125                 if (session) {
1126                         const struct lttng_enum *_enum;
1127
1128                         _enum = lttng_ust_enum_get_from_desc(session, lt->u.enum_nestable.desc);
1129                         if (!_enum)
1130                                 return -EINVAL;
1131                         ut->u.enum_nestable.id = _enum->id;
1132                 } else {
1133                         ut->u.enum_nestable.id = -1ULL;
1134                 }
1135                 break;
1136         }
1137         default:
1138                 return -EINVAL;
1139         }
1140         return 0;
1141 }
1142
1143 static
1144 int serialize_one_field(struct lttng_session *session,
1145                 struct ustctl_field *fields, size_t *iter_output,
1146                 const struct lttng_event_field *lf)
1147 {
1148         /* skip 'nowrite' fields */
1149         if (lf->nowrite)
1150                 return 0;
1151
1152         return serialize_one_type(session, fields, iter_output, lf->name, &lf->type);
1153 }
1154
1155 static
1156 int serialize_fields(struct lttng_session *session,
1157                 struct ustctl_field *ustctl_fields,
1158                 size_t *iter_output, size_t nr_lttng_fields,
1159                 const struct lttng_event_field *lttng_fields)
1160 {
1161         int ret;
1162         size_t i;
1163
1164         for (i = 0; i < nr_lttng_fields; i++) {
1165                 ret = serialize_one_field(session, ustctl_fields,
1166                                 iter_output, &lttng_fields[i]);
1167                 if (ret)
1168                         return ret;
1169         }
1170         return 0;
1171 }
1172
1173 static
1174 int alloc_serialize_fields(struct lttng_session *session,
1175                 size_t *_nr_write_fields,
1176                 struct ustctl_field **ustctl_fields,
1177                 size_t nr_fields,
1178                 const struct lttng_event_field *lttng_fields)
1179 {
1180         struct ustctl_field *fields;
1181         int ret;
1182         size_t iter_output = 0;
1183         ssize_t nr_write_fields;
1184
1185         nr_write_fields = count_fields_recursive(nr_fields, lttng_fields);
1186         if (nr_write_fields < 0) {
1187                 return (int) nr_write_fields;
1188         }
1189
1190         fields = zmalloc(nr_write_fields * sizeof(*fields));
1191         if (!fields)
1192                 return -ENOMEM;
1193
1194         ret = serialize_fields(session, fields, &iter_output, nr_fields,
1195                         lttng_fields);
1196         if (ret)
1197                 goto error_type;
1198
1199         *_nr_write_fields = nr_write_fields;
1200         *ustctl_fields = fields;
1201         return 0;
1202
1203 error_type:
1204         free(fields);
1205         return ret;
1206 }
1207
1208 static
1209 int serialize_entries(struct ustctl_enum_entry **_entries,
1210                 size_t nr_entries,
1211                 const struct lttng_enum_entry *lttng_entries)
1212 {
1213         struct ustctl_enum_entry *entries;
1214         int i;
1215
1216         /* Serialize the entries */
1217         entries = zmalloc(nr_entries * sizeof(*entries));
1218         if (!entries)
1219                 return -ENOMEM;
1220         for (i = 0; i < nr_entries; i++) {
1221                 struct ustctl_enum_entry *uentry;
1222                 const struct lttng_enum_entry *lentry;
1223
1224                 uentry = &entries[i];
1225                 lentry = &lttng_entries[i];
1226
1227                 uentry->start.value = lentry->start.value;
1228                 uentry->start.signedness = lentry->start.signedness;
1229                 uentry->end.value = lentry->end.value;
1230                 uentry->end.signedness = lentry->end.signedness;
1231                 strncpy(uentry->string, lentry->string, LTTNG_UST_SYM_NAME_LEN);
1232                 uentry->string[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1233
1234                 if (lentry->u.extra.options & LTTNG_ENUM_ENTRY_OPTION_IS_AUTO) {
1235                         uentry->u.extra.options |=
1236                                 USTCTL_UST_ENUM_ENTRY_OPTION_IS_AUTO;
1237                 }
1238         }
1239         *_entries = entries;
1240         return 0;
1241 }
1242
1243 static
1244 int serialize_ctx_fields(struct lttng_session *session,
1245                 size_t *_nr_write_fields,
1246                 struct ustctl_field **ustctl_fields,
1247                 size_t nr_fields,
1248                 const struct lttng_ctx_field *lttng_fields)
1249 {
1250         struct ustctl_field *fields;
1251         int ret;
1252         size_t i, iter_output = 0;
1253         ssize_t nr_write_fields;
1254
1255         nr_write_fields = count_ctx_fields_recursive(nr_fields,
1256                         lttng_fields);
1257         if (nr_write_fields < 0) {
1258                 return (int) nr_write_fields;
1259         }
1260
1261         fields = zmalloc(nr_write_fields * sizeof(*fields));
1262         if (!fields)
1263                 return -ENOMEM;
1264
1265         for (i = 0; i < nr_fields; i++) {
1266                 ret = serialize_one_field(session, fields, &iter_output,
1267                                 &lttng_fields[i].event_field);
1268                 if (ret)
1269                         goto error_type;
1270         }
1271
1272         *_nr_write_fields = nr_write_fields;
1273         *ustctl_fields = fields;
1274         return 0;
1275
1276 error_type:
1277         free(fields);
1278         return ret;
1279 }
1280
1281 /*
1282  * Returns 0 on success, negative error value on error.
1283  */
1284 int ustcomm_register_event(int sock,
1285         struct lttng_session *session,
1286         int session_objd,               /* session descriptor */
1287         int channel_objd,               /* channel descriptor */
1288         const char *event_name,         /* event name (input) */
1289         int loglevel,
1290         const char *signature,          /* event signature (input) */
1291         size_t nr_fields,               /* fields */
1292         const struct lttng_event_field *lttng_fields,
1293         const char *model_emf_uri,
1294         uint32_t *id)                   /* event id (output) */
1295 {
1296         ssize_t len;
1297         struct {
1298                 struct ustcomm_notify_hdr header;
1299                 struct ustcomm_notify_event_msg m;
1300         } msg;
1301         struct {
1302                 struct ustcomm_notify_hdr header;
1303                 struct ustcomm_notify_event_reply r;
1304         } reply;
1305         size_t signature_len, fields_len, model_emf_uri_len;
1306         struct ustctl_field *fields = NULL;
1307         size_t nr_write_fields = 0;
1308         int ret;
1309
1310         memset(&msg, 0, sizeof(msg));
1311         msg.header.notify_cmd = USTCTL_NOTIFY_CMD_EVENT;
1312         msg.m.session_objd = session_objd;
1313         msg.m.channel_objd = channel_objd;
1314         strncpy(msg.m.event_name, event_name, LTTNG_UST_SYM_NAME_LEN);
1315         msg.m.event_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1316         msg.m.loglevel = loglevel;
1317         signature_len = strlen(signature) + 1;
1318         msg.m.signature_len = signature_len;
1319
1320         /* Calculate fields len, serialize fields. */
1321         if (nr_fields > 0) {
1322                 ret = alloc_serialize_fields(session, &nr_write_fields, &fields,
1323                                 nr_fields, lttng_fields);
1324                 if (ret)
1325                         return ret;
1326         }
1327
1328         fields_len = sizeof(*fields) * nr_write_fields;
1329         msg.m.fields_len = fields_len;
1330         if (model_emf_uri) {
1331                 model_emf_uri_len = strlen(model_emf_uri) + 1;
1332         } else {
1333                 model_emf_uri_len = 0;
1334         }
1335         msg.m.model_emf_uri_len = model_emf_uri_len;
1336
1337         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1338         if (len > 0 && len != sizeof(msg)) {
1339                 ret = -EIO;
1340                 goto error_fields;
1341         }
1342         if (len < 0) {
1343                 ret = len;
1344                 goto error_fields;
1345         }
1346
1347         /* send signature */
1348         len = ustcomm_send_unix_sock(sock, signature, signature_len);
1349         if (len > 0 && len != signature_len) {
1350                 ret = -EIO;
1351                 goto error_fields;
1352         }
1353         if (len < 0) {
1354                 ret = len;
1355                 goto error_fields;
1356         }
1357
1358         /* send fields */
1359         if (fields_len > 0) {
1360                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
1361                 if (len > 0 && len != fields_len) {
1362                         ret = -EIO;
1363                         goto error_fields;
1364                 }
1365                 if (len < 0) {
1366                         ret = len;
1367                         goto error_fields;
1368                 }
1369         }
1370         free(fields);
1371
1372         if (model_emf_uri_len) {
1373                 /* send model_emf_uri */
1374                 len = ustcomm_send_unix_sock(sock, model_emf_uri,
1375                                 model_emf_uri_len);
1376                 if (len > 0 && len != model_emf_uri_len) {
1377                         return -EIO;
1378                 }
1379                 if (len < 0) {
1380                         return len;
1381                 }
1382         }
1383
1384         /* receive reply */
1385         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1386         switch (len) {
1387         case 0: /* orderly shutdown */
1388                 return -EPIPE;
1389         case sizeof(reply):
1390                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1391                         ERR("Unexpected result message command "
1392                                 "expected: %u vs received: %u\n",
1393                                 msg.header.notify_cmd, reply.header.notify_cmd);
1394                         return -EINVAL;
1395                 }
1396                 if (reply.r.ret_code > 0)
1397                         return -EINVAL;
1398                 if (reply.r.ret_code < 0)
1399                         return reply.r.ret_code;
1400                 *id = reply.r.event_id;
1401                 DBG("Sent register event notification for name \"%s\": ret_code %d, event_id %u\n",
1402                         event_name, reply.r.ret_code, reply.r.event_id);
1403                 return 0;
1404         default:
1405                 if (len < 0) {
1406                         /* Transport level error */
1407                         if (errno == EPIPE || errno == ECONNRESET)
1408                                 len = -errno;
1409                         return len;
1410                 } else {
1411                         ERR("incorrect message size: %zd\n", len);
1412                         return len;
1413                 }
1414         }
1415         /* Unreached. */
1416
1417         /* Error path only. */
1418 error_fields:
1419         free(fields);
1420         return ret;
1421 }
1422
1423 /*
1424  * Returns 0 on success, negative error value on error.
1425  * Returns -EPIPE or -ECONNRESET if other end has hung up.
1426  */
1427 int ustcomm_register_enum(int sock,
1428         int session_objd,               /* session descriptor */
1429         const char *enum_name,          /* enum name (input) */
1430         size_t nr_entries,              /* entries */
1431         const struct lttng_enum_entry *lttng_entries,
1432         uint64_t *id)
1433 {
1434         ssize_t len;
1435         struct {
1436                 struct ustcomm_notify_hdr header;
1437                 struct ustcomm_notify_enum_msg m;
1438         } msg;
1439         struct {
1440                 struct ustcomm_notify_hdr header;
1441                 struct ustcomm_notify_enum_reply r;
1442         } reply;
1443         size_t entries_len;
1444         struct ustctl_enum_entry *entries = NULL;
1445         int ret;
1446
1447         memset(&msg, 0, sizeof(msg));
1448         msg.header.notify_cmd = USTCTL_NOTIFY_CMD_ENUM;
1449         msg.m.session_objd = session_objd;
1450         strncpy(msg.m.enum_name, enum_name, LTTNG_UST_SYM_NAME_LEN);
1451         msg.m.enum_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1452
1453         /* Calculate entries len, serialize entries. */
1454         if (nr_entries > 0) {
1455                 ret = serialize_entries(&entries,
1456                                 nr_entries, lttng_entries);
1457                 if (ret)
1458                         return ret;
1459         }
1460
1461         entries_len = sizeof(*entries) * nr_entries;
1462         msg.m.entries_len = entries_len;
1463
1464         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1465         if (len > 0 && len != sizeof(msg)) {
1466                 ret = -EIO;
1467                 goto error_entries;
1468         }
1469         if (len < 0) {
1470                 ret = len;
1471                 goto error_entries;
1472         }
1473
1474         /* send entries */
1475         if (entries_len > 0) {
1476                 len = ustcomm_send_unix_sock(sock, entries, entries_len);
1477                 if (len > 0 && len != entries_len) {
1478                         ret = -EIO;
1479                         goto error_entries;
1480                 }
1481                 if (len < 0) {
1482                         ret = len;
1483                         goto error_entries;
1484                 }
1485         }
1486         free(entries);
1487         entries = NULL;
1488
1489         /* receive reply */
1490         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1491         switch (len) {
1492         case 0: /* orderly shutdown */
1493                 return -EPIPE;
1494         case sizeof(reply):
1495                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1496                         ERR("Unexpected result message command "
1497                                 "expected: %u vs received: %u\n",
1498                                 msg.header.notify_cmd, reply.header.notify_cmd);
1499                         return -EINVAL;
1500                 }
1501                 if (reply.r.ret_code > 0)
1502                         return -EINVAL;
1503                 if (reply.r.ret_code < 0)
1504                         return reply.r.ret_code;
1505                 *id = reply.r.enum_id;
1506                 DBG("Sent register enum notification for name \"%s\": ret_code %d\n",
1507                         enum_name, reply.r.ret_code);
1508                 return 0;
1509         default:
1510                 if (len < 0) {
1511                         /* Transport level error */
1512                         if (errno == EPIPE || errno == ECONNRESET)
1513                                 len = -errno;
1514                         return len;
1515                 } else {
1516                         ERR("incorrect message size: %zd\n", len);
1517                         return len;
1518                 }
1519         }
1520         return ret;
1521
1522 error_entries:
1523         free(entries);
1524         return ret;
1525 }
1526
1527 /*
1528  * Returns 0 on success, negative error value on error.
1529  * Returns -EPIPE or -ECONNRESET if other end has hung up.
1530  */
1531 int ustcomm_register_channel(int sock,
1532         struct lttng_session *session,
1533         int session_objd,               /* session descriptor */
1534         int channel_objd,               /* channel descriptor */
1535         size_t nr_ctx_fields,
1536         const struct lttng_ctx_field *ctx_fields,
1537         uint32_t *chan_id,              /* channel id (output) */
1538         int *header_type)               /* header type (output) */
1539 {
1540         ssize_t len;
1541         struct {
1542                 struct ustcomm_notify_hdr header;
1543                 struct ustcomm_notify_channel_msg m;
1544         } msg;
1545         struct {
1546                 struct ustcomm_notify_hdr header;
1547                 struct ustcomm_notify_channel_reply r;
1548         } reply;
1549         size_t fields_len;
1550         struct ustctl_field *fields = NULL;
1551         int ret;
1552         size_t nr_write_fields = 0;
1553
1554         memset(&msg, 0, sizeof(msg));
1555         msg.header.notify_cmd = USTCTL_NOTIFY_CMD_CHANNEL;
1556         msg.m.session_objd = session_objd;
1557         msg.m.channel_objd = channel_objd;
1558
1559         /* Calculate fields len, serialize fields. */
1560         if (nr_ctx_fields > 0) {
1561                 ret = serialize_ctx_fields(session, &nr_write_fields, &fields,
1562                                 nr_ctx_fields, ctx_fields);
1563                 if (ret)
1564                         return ret;
1565         }
1566
1567         fields_len = sizeof(*fields) * nr_write_fields;
1568         msg.m.ctx_fields_len = fields_len;
1569         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1570         if (len > 0 && len != sizeof(msg)) {
1571                 free(fields);
1572                 return -EIO;
1573         }
1574         if (len < 0) {
1575                 free(fields);
1576                 return len;
1577         }
1578
1579         /* send fields */
1580         if (fields_len > 0) {
1581                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
1582                 free(fields);
1583                 if (len > 0 && len != fields_len) {
1584                         return -EIO;
1585                 }
1586                 if (len < 0) {
1587                         return len;
1588                 }
1589         } else {
1590                 free(fields);
1591         }
1592
1593         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1594         switch (len) {
1595         case 0: /* orderly shutdown */
1596                 return -EPIPE;
1597         case sizeof(reply):
1598                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1599                         ERR("Unexpected result message command "
1600                                 "expected: %u vs received: %u\n",
1601                                 msg.header.notify_cmd, reply.header.notify_cmd);
1602                         return -EINVAL;
1603                 }
1604                 if (reply.r.ret_code > 0)
1605                         return -EINVAL;
1606                 if (reply.r.ret_code < 0)
1607                         return reply.r.ret_code;
1608                 *chan_id = reply.r.chan_id;
1609                 switch (reply.r.header_type) {
1610                 case 1:
1611                 case 2:
1612                         *header_type = reply.r.header_type;
1613                         break;
1614                 default:
1615                         ERR("Unexpected channel header type %u\n",
1616                                 reply.r.header_type);
1617                         return -EINVAL;
1618                 }
1619                 DBG("Sent register channel notification: chan_id %d, header_type %d\n",
1620                         reply.r.chan_id, reply.r.header_type);
1621                 return 0;
1622         default:
1623                 if (len < 0) {
1624                         /* Transport level error */
1625                         if (errno == EPIPE || errno == ECONNRESET)
1626                                 len = -errno;
1627                         return len;
1628                 } else {
1629                         ERR("incorrect message size: %zd\n", len);
1630                         return len;
1631                 }
1632         }
1633 }
1634
1635 /*
1636  * Set socket reciving timeout.
1637  */
1638 int ustcomm_setsockopt_rcv_timeout(int sock, unsigned int msec)
1639 {
1640         int ret;
1641         struct timeval tv;
1642
1643         tv.tv_sec = msec / 1000;
1644         tv.tv_usec = (msec * 1000 % 1000000);
1645
1646         ret = setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
1647         if (ret < 0) {
1648                 PERROR("setsockopt SO_RCVTIMEO");
1649                 ret = -errno;
1650         }
1651
1652         return ret;
1653 }
1654
1655 /*
1656  * Set socket sending timeout.
1657  */
1658 int ustcomm_setsockopt_snd_timeout(int sock, unsigned int msec)
1659 {
1660         int ret;
1661         struct timeval tv;
1662
1663         tv.tv_sec = msec / 1000;
1664         tv.tv_usec = (msec * 1000) % 1000000;
1665
1666         ret = setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
1667         if (ret < 0) {
1668                 PERROR("setsockopt SO_SNDTIMEO");
1669                 ret = -errno;
1670         }
1671
1672         return ret;
1673 }