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

   1 /*
   2  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C)  2011-2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; only
   8  * version 2.1 of the License.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #define _GNU_SOURCE
  21 #include <limits.h>
  22 #include <stdint.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/socket.h>
  27 #include <sys/stat.h>
  28 #include <sys/types.h>
  29 #include <sys/un.h>
  30 #include <unistd.h>
  31 #include <assert.h>
  32 #include <errno.h>
  33 #include <fcntl.h>
  34
  35 #include <lttng/ust-ctl.h>
  36 #include <ust-comm.h>
  37 #include <ust-fd.h>
  38 #include <helper.h>
  39 #include <lttng/ust-error.h>
  40 #include <lttng/ust-events.h>
  41 #include <lttng/ust-dynamic-type.h>
  42 #include <usterr-signal-safe.h>
  43
  44 #include "../liblttng-ust/compat.h"
  45
  46 #define USTCOMM_CODE_OFFSET(code)       \
  47         (code == LTTNG_UST_OK ? 0 : (code - LTTNG_UST_ERR + 1))
  48
  49 #define USTCOMM_MAX_SEND_FDS    4
  50
  51 static
  52 ssize_t count_fields_recursive(size_t nr_fields,
  53                 const struct lttng_event_field *lttng_fields);
  54 static
  55 int serialize_one_field(struct lttng_session *session,
  56                 struct ustctl_field *fields, size_t *iter_output,
  57                 const struct lttng_event_field *lf);
  58
  59 /*
  60  * Human readable error message.
  61  */
  62 static const char *ustcomm_readable_code[] = {
  63         [ USTCOMM_CODE_OFFSET(LTTNG_UST_OK) ] = "Success",
  64         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR) ] = "Unknown error",
  65         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_NOENT) ] = "No entry",
  66         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_EXIST) ] = "Object already exists",
  67         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL) ] = "Invalid argument",
  68         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_PERM) ] = "Permission denied",
  69         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_NOSYS) ] = "Not implemented",
  70         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_EXITING) ] = "Process is exiting",
  71
  72         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL_MAGIC) ] = "Invalid magic number",
  73         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL_SOCKET_TYPE) ] = "Invalid socket type",
  74         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_UNSUP_MAJOR) ] = "Unsupported major version",
  75 };
  76
  77 /*
  78  * lttng_ust_strerror
  79  *
  80  * Receives positive error value.
  81  * Return ptr to string representing a human readable
  82  * error code from the ustcomm_return_code enum.
  83  */
  84 const char *lttng_ust_strerror(int code)
  85 {
  86         if (code == LTTNG_UST_OK)
  87                 return ustcomm_readable_code[USTCOMM_CODE_OFFSET(code)];
  88         if (code < LTTNG_UST_ERR)
  89                 return strerror(code);
  90         if (code >= LTTNG_UST_ERR_NR)
  91                 code = LTTNG_UST_ERR;
  92         return ustcomm_readable_code[USTCOMM_CODE_OFFSET(code)];
  93 }
  94
  95 /*
  96  * ustcomm_connect_unix_sock
  97  *
  98  * Connect to unix socket using the path name.
  99  *
 100  * Caller handles FD tracker.
 101  */
 102 int ustcomm_connect_unix_sock(const char *pathname, long timeout)
 103 {
 104         struct sockaddr_un sun;
 105         int fd, ret;
 106
 107         /*
 108          * libust threads require the close-on-exec flag for all
 109          * resources so it does not leak file descriptors upon exec.
 110          */
 111         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 112         if (fd < 0) {
 113                 PERROR("socket");
 114                 ret = -errno;
 115                 goto error;
 116         }
 117         if (timeout >= 0) {
 118                 /* Give at least 10ms. */
 119                 if (timeout < 10)
 120                         timeout = 10;
 121                 ret = ustcomm_setsockopt_snd_timeout(fd, timeout);
 122                 if (ret < 0) {
 123                         WARN("Error setting connect socket send timeout");
 124                 }
 125         }
 126         ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
 127         if (ret < 0) {
 128                 PERROR("fcntl");
 129                 ret = -errno;
 130                 goto error_fcntl;
 131         }
 132
 133         memset(&sun, 0, sizeof(sun));
 134         sun.sun_family = AF_UNIX;
 135         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 136         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 137
 138         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 139         if (ret < 0) {
 140                 /*
 141                  * Don't print message on connect ENOENT error, because
 142                  * connect is used in normal execution to detect if
 143                  * sessiond is alive. ENOENT is when the unix socket
 144                  * file does not exist, and ECONNREFUSED is when the
 145                  * file exists but no sessiond is listening.
 146                  */
 147                 if (errno != ECONNREFUSED && errno != ECONNRESET
 148                                 && errno != ENOENT && errno != EACCES)
 149                         PERROR("connect");
 150                 ret = -errno;
 151                 if (ret == -ECONNREFUSED || ret == -ECONNRESET)
 152                         ret = -EPIPE;
 153                 goto error_connect;
 154         }
 155
 156         return fd;
 157
 158 error_connect:
 159 error_fcntl:
 160         {
 161                 int closeret;
 162
 163                 closeret = close(fd);
 164                 if (closeret)
 165                         PERROR("close");
 166         }
 167 error:
 168         return ret;
 169 }
 170
 171 /*
 172  * ustcomm_accept_unix_sock
 173  *
 174  * Do an accept(2) on the sock and return the
 175  * new file descriptor. The socket MUST be bind(2) before.
 176  */
 177 int ustcomm_accept_unix_sock(int sock)
 178 {
 179         int new_fd;
 180         struct sockaddr_un sun;
 181         socklen_t len = 0;
 182
 183         /* Blocking call */
 184         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 185         if (new_fd < 0) {
 186                 if (errno != ECONNABORTED)
 187                         PERROR("accept");
 188                 new_fd = -errno;
 189                 if (new_fd == -ECONNABORTED)
 190                         new_fd = -EPIPE;
 191         }
 192         return new_fd;
 193 }
 194
 195 /*
 196  * ustcomm_create_unix_sock
 197  *
 198  * Creates a AF_UNIX local socket using pathname
 199  * bind the socket upon creation and return the fd.
 200  */
 201 int ustcomm_create_unix_sock(const char *pathname)
 202 {
 203         struct sockaddr_un sun;
 204         int fd, ret;
 205
 206         /* Create server socket */
 207         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 208                 PERROR("socket");
 209                 ret = -errno;
 210                 goto error;
 211         }
 212
 213         memset(&sun, 0, sizeof(sun));
 214         sun.sun_family = AF_UNIX;
 215         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 216         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 217
 218         /* Unlink the old file if present */
 219         (void) unlink(pathname);
 220         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 221         if (ret < 0) {
 222                 PERROR("bind");
 223                 ret = -errno;
 224                 goto error_close;
 225         }
 226
 227         return fd;
 228
 229 error_close:
 230         {
 231                 int closeret;
 232
 233                 closeret = close(fd);
 234                 if (closeret) {
 235                         PERROR("close");
 236                 }
 237         }
 238 error:
 239         return ret;
 240 }
 241
 242 /*
 243  * ustcomm_listen_unix_sock
 244  *
 245  * Make the socket listen using LTTNG_UST_COMM_MAX_LISTEN.
 246  */
 247 int ustcomm_listen_unix_sock(int sock)
 248 {
 249         int ret;
 250
 251         ret = listen(sock, LTTNG_UST_COMM_MAX_LISTEN);
 252         if (ret < 0) {
 253                 ret = -errno;
 254                 PERROR("listen");
 255         }
 256
 257         return ret;
 258 }
 259
 260 /*
 261  * ustcomm_close_unix_sock
 262  *
 263  * Shutdown cleanly a unix socket.
 264  *
 265  * Handles fd tracker internally.
 266  */
 267 int ustcomm_close_unix_sock(int sock)
 268 {
 269         int ret;
 270
 271         lttng_ust_lock_fd_tracker();
 272         ret = close(sock);
 273         if (!ret) {
 274                 lttng_ust_delete_fd_from_tracker(sock);
 275         } else {
 276                 PERROR("close");
 277                 ret = -errno;
 278         }
 279         lttng_ust_unlock_fd_tracker();
 280
 281         return ret;
 282 }
 283
 284 /*
 285  * ustcomm_recv_unix_sock
 286  *
 287  * Receive data of size len in put that data into
 288  * the buf param. Using recvmsg API.
 289  * Return the size of received data.
 290  * Return 0 on orderly shutdown.
 291  */
 292 ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len)
 293 {
 294         struct msghdr msg;
 295         struct iovec iov[1];
 296         ssize_t ret = -1;
 297         size_t len_last;
 298
 299         memset(&msg, 0, sizeof(msg));
 300
 301         iov[0].iov_base = buf;
 302         iov[0].iov_len = len;
 303         msg.msg_iov = iov;
 304         msg.msg_iovlen = 1;
 305
 306         do {
 307                 len_last = iov[0].iov_len;
 308                 ret = recvmsg(sock, &msg, 0);
 309                 if (ret > 0) {
 310                         iov[0].iov_base += ret;
 311                         iov[0].iov_len -= ret;
 312                         assert(ret <= len_last);
 313                 }
 314         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 315
 316         if (ret < 0) {
 317                 int shutret;
 318
 319                 if (errno != EPIPE && errno != ECONNRESET && errno != ECONNREFUSED)
 320                         PERROR("recvmsg");
 321                 ret = -errno;
 322                 if (ret == -ECONNRESET || ret == -ECONNREFUSED)
 323                         ret = -EPIPE;
 324
 325                 shutret = shutdown(sock, SHUT_RDWR);
 326                 if (shutret)
 327                         ERR("Socket shutdown error");
 328         } else if (ret > 0) {
 329                 ret = len;
 330         }
 331         /* ret = 0 means an orderly shutdown. */
 332
 333         return ret;
 334 }
 335
 336 /*
 337  * ustcomm_send_unix_sock
 338  *
 339  * Send buf data of size len. Using sendmsg API.
 340  * Return the size of sent data.
 341  */
 342 ssize_t ustcomm_send_unix_sock(int sock, const void *buf, size_t len)
 343 {
 344         struct msghdr msg;
 345         struct iovec iov[1];
 346         ssize_t ret;
 347
 348         memset(&msg, 0, sizeof(msg));
 349
 350         iov[0].iov_base = (void *) buf;
 351         iov[0].iov_len = len;
 352         msg.msg_iov = iov;
 353         msg.msg_iovlen = 1;
 354
 355         /*
 356          * Using the MSG_NOSIGNAL when sending data from sessiond to
 357          * libust, so libust does not receive an unhandled SIGPIPE or
 358          * SIGURG. The sessiond receiver side can be made more resilient
 359          * by ignoring SIGPIPE, but we don't have this luxury on the
 360          * libust side.
 361          */
 362         do {
 363                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 364         } while (ret < 0 && errno == EINTR);
 365
 366         if (ret < 0) {
 367                 int shutret;
 368
 369                 if (errno != EPIPE && errno != ECONNRESET)
 370                         PERROR("sendmsg");
 371                 ret = -errno;
 372                 if (ret == -ECONNRESET)
 373                         ret = -EPIPE;
 374
 375                 shutret = shutdown(sock, SHUT_RDWR);
 376                 if (shutret)
 377                         ERR("Socket shutdown error");
 378         }
 379
 380         return ret;
 381 }
 382
 383 /*
 384  * Send a message accompanied by fd(s) over a unix socket.
 385  *
 386  * Returns the size of data sent, or negative error value.
 387  */
 388 ssize_t ustcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 389 {
 390         struct msghdr msg;
 391         struct cmsghdr *cmptr;
 392         struct iovec iov[1];
 393         ssize_t ret = -1;
 394         unsigned int sizeof_fds = nb_fd * sizeof(int);
 395         char tmp[CMSG_SPACE(sizeof_fds)];
 396         char dummy = 0;
 397
 398         memset(&msg, 0, sizeof(msg));
 399         memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
 400
 401         if (nb_fd > USTCOMM_MAX_SEND_FDS)
 402                 return -EINVAL;
 403
 404         msg.msg_control = (caddr_t)tmp;
 405         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 406
 407         cmptr = CMSG_FIRSTHDR(&msg);
 408         if (!cmptr)
 409                 return -EINVAL;
 410         cmptr->cmsg_level = SOL_SOCKET;
 411         cmptr->cmsg_type = SCM_RIGHTS;
 412         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 413         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 414         /* Sum of the length of all control messages in the buffer: */
 415         msg.msg_controllen = cmptr->cmsg_len;
 416
 417         iov[0].iov_base = &dummy;
 418         iov[0].iov_len = 1;
 419         msg.msg_iov = iov;
 420         msg.msg_iovlen = 1;
 421
 422         do {
 423                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 424         } while (ret < 0 && errno == EINTR);
 425         if (ret < 0) {
 426                 /*
 427                  * We consider EPIPE and ECONNRESET as expected.
 428                  */
 429                 if (errno != EPIPE && errno != ECONNRESET) {
 430                         PERROR("sendmsg");
 431                 }
 432                 ret = -errno;
 433                 if (ret == -ECONNRESET)
 434                         ret = -EPIPE;
 435         }
 436         return ret;
 437 }
 438
 439 /*
 440  * Recv a message accompanied by fd(s) from a unix socket.
 441  *
 442  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 443  * actually received in nb_fd.
 444  * Returns -EPIPE on orderly shutdown.
 445  */
 446 ssize_t ustcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 447 {
 448         struct iovec iov[1];
 449         ssize_t ret = 0;
 450         struct cmsghdr *cmsg;
 451         size_t sizeof_fds = nb_fd * sizeof(int);
 452         char recv_fd[CMSG_SPACE(sizeof_fds)];
 453         struct msghdr msg;
 454         char dummy;
 455
 456         memset(&msg, 0, sizeof(msg));
 457
 458         /* Prepare to receive the structures */
 459         iov[0].iov_base = &dummy;
 460         iov[0].iov_len = 1;
 461         msg.msg_iov = iov;
 462         msg.msg_iovlen = 1;
 463         msg.msg_control = recv_fd;
 464         msg.msg_controllen = sizeof(recv_fd);
 465
 466         do {
 467                 ret = recvmsg(sock, &msg, 0);
 468         } while (ret < 0 && errno == EINTR);
 469         if (ret < 0) {
 470                 if (errno != EPIPE && errno != ECONNRESET) {
 471                         PERROR("recvmsg fds");
 472                 }
 473                 ret = -errno;
 474                 if (ret == -ECONNRESET)
 475                         ret = -EPIPE;
 476                 goto end;
 477         }
 478         if (ret == 0) {
 479                 /* orderly shutdown */
 480                 ret = -EPIPE;
 481                 goto end;
 482         }
 483         if (ret != 1) {
 484                 ERR("Error: Received %zd bytes, expected %d\n",
 485                                 ret, 1);
 486                 goto end;
 487         }
 488         if (msg.msg_flags & MSG_CTRUNC) {
 489                 ERR("Error: Control message truncated.\n");
 490                 ret = -1;
 491                 goto end;
 492         }
 493         cmsg = CMSG_FIRSTHDR(&msg);
 494         if (!cmsg) {
 495                 ERR("Error: Invalid control message header\n");
 496                 ret = -1;
 497                 goto end;
 498         }
 499         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 500                 ERR("Didn't received any fd\n");
 501                 ret = -1;
 502                 goto end;
 503         }
 504         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 505                 ERR("Error: Received %zu bytes of ancillary data, expected %zu\n",
 506                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 507                 ret = -1;
 508                 goto end;
 509         }
 510         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 511         ret = nb_fd;
 512 end:
 513         return ret;
 514 }
 515
 516 int ustcomm_send_app_msg(int sock, struct ustcomm_ust_msg *lum)
 517 {
 518         ssize_t len;
 519
 520         len = ustcomm_send_unix_sock(sock, lum, sizeof(*lum));
 521         switch (len) {
 522         case sizeof(*lum):
 523                 break;
 524         default:
 525                 if (len < 0) {
 526                         return len;
 527                 } else {
 528                         ERR("incorrect message size: %zd\n", len);
 529                         return -EINVAL;
 530                 }
 531         }
 532         return 0;
 533 }
 534
 535 int ustcomm_recv_app_reply(int sock, struct ustcomm_ust_reply *lur,
 536                           uint32_t expected_handle, uint32_t expected_cmd)
 537 {
 538         ssize_t len;
 539
 540         memset(lur, 0, sizeof(*lur));
 541         len = ustcomm_recv_unix_sock(sock, lur, sizeof(*lur));
 542         switch (len) {
 543         case 0: /* orderly shutdown */
 544                 return -EPIPE;
 545         case sizeof(*lur):
 546         {
 547                 int err = 0;
 548
 549                 if (lur->handle != expected_handle) {
 550                         ERR("Unexpected result message handle: "
 551                                 "expected: %u vs received: %u\n",
 552                                 expected_handle, lur->handle);
 553                         err = 1;
 554                 }
 555                 if (lur->cmd != expected_cmd) {
 556                         ERR("Unexpected result message command "
 557                                 "expected: %u vs received: %u\n",
 558                                 expected_cmd, lur->cmd);
 559                         err = 1;
 560                 }
 561                 if (err) {
 562                         return -EINVAL;
 563                 } else {
 564                         return lur->ret_code;
 565                 }
 566         }
 567         default:
 568                 if (len >= 0) {
 569                         ERR("incorrect message size: %zd\n", len);
 570                 }
 571                 return len;
 572         }
 573 }
 574
 575 int ustcomm_send_app_cmd(int sock,
 576                         struct ustcomm_ust_msg *lum,
 577                         struct ustcomm_ust_reply *lur)
 578 {
 579         int ret;
 580
 581         ret = ustcomm_send_app_msg(sock, lum);
 582         if (ret)
 583                 return ret;
 584         ret = ustcomm_recv_app_reply(sock, lur, lum->handle, lum->cmd);
 585         if (ret > 0)
 586                 return -EIO;
 587         return ret;
 588 }
 589
 590 /*
 591  * chan_data is allocated internally if this function returns the
 592  * expected var_len.
 593  */
 594 ssize_t ustcomm_recv_channel_from_sessiond(int sock,
 595                 void **_chan_data, uint64_t var_len,
 596                 int *_wakeup_fd)
 597 {
 598         void *chan_data;
 599         ssize_t len, nr_fd;
 600         int wakeup_fd, ret;
 601
 602         if (var_len > LTTNG_UST_CHANNEL_DATA_MAX_LEN) {
 603                 len = -EINVAL;
 604                 goto error_check;
 605         }
 606         /* Receive variable length data */
 607         chan_data = zmalloc(var_len);
 608         if (!chan_data) {
 609                 len = -ENOMEM;
 610                 goto error_alloc;
 611         }
 612         len = ustcomm_recv_unix_sock(sock, chan_data, var_len);
 613         if (len != var_len) {
 614                 goto error_recv;
 615         }
 616         /* recv wakeup fd */
 617         lttng_ust_lock_fd_tracker();
 618         nr_fd = ustcomm_recv_fds_unix_sock(sock, &wakeup_fd, 1);
 619         if (nr_fd <= 0) {
 620                 lttng_ust_unlock_fd_tracker();
 621                 if (nr_fd < 0) {
 622                         len = nr_fd;
 623                         goto error_recv;
 624                 } else {
 625                         len = -EIO;
 626                         goto error_recv;
 627                 }
 628         }
 629
 630         ret = lttng_ust_add_fd_to_tracker(wakeup_fd);
 631         if (ret < 0) {
 632                 ret = close(wakeup_fd);
 633                 if (ret) {
 634                         PERROR("close on wakeup_fd");
 635                 }
 636                 len = -EIO;
 637                 lttng_ust_unlock_fd_tracker();
 638                 goto error_recv;
 639         }
 640
 641         *_wakeup_fd = ret;
 642         lttng_ust_unlock_fd_tracker();
 643
 644         *_chan_data = chan_data;
 645         return len;
 646
 647 error_recv:
 648         free(chan_data);
 649 error_alloc:
 650 error_check:
 651         return len;
 652 }
 653
 654 int ustcomm_recv_stream_from_sessiond(int sock,
 655                 uint64_t *memory_map_size,
 656                 int *shm_fd, int *wakeup_fd)
 657 {
 658         ssize_t len;
 659         int ret;
 660         int fds[2];
 661
 662         /* recv shm fd and wakeup fd */
 663         lttng_ust_lock_fd_tracker();
 664         len = ustcomm_recv_fds_unix_sock(sock, fds, 2);
 665         if (len <= 0) {
 666                 lttng_ust_unlock_fd_tracker();
 667                 if (len < 0) {
 668                         ret = len;
 669                         goto error;
 670                 } else {
 671                         ret = -EIO;
 672                         goto error;
 673                 }
 674         }
 675
 676         ret = lttng_ust_add_fd_to_tracker(fds[0]);
 677         if (ret < 0) {
 678                 ret = close(fds[0]);
 679                 if (ret) {
 680                         PERROR("close on received shm_fd");
 681                 }
 682                 ret = -EIO;
 683                 lttng_ust_unlock_fd_tracker();
 684                 goto error;
 685         }
 686         *shm_fd = ret;
 687
 688         ret = lttng_ust_add_fd_to_tracker(fds[1]);
 689         if (ret < 0) {
 690                 ret = close(*shm_fd);
 691                 if (ret) {
 692                         PERROR("close on shm_fd");
 693                 }
 694                 *shm_fd = -1;
 695                 ret = close(fds[1]);
 696                 if (ret) {
 697                         PERROR("close on received wakeup_fd");
 698                 }
 699                 ret = -EIO;
 700                 lttng_ust_unlock_fd_tracker();
 701                 goto error;
 702         }
 703         *wakeup_fd = ret;
 704         lttng_ust_unlock_fd_tracker();
 705         return 0;
 706
 707 error:
 708         return ret;
 709 }
 710
 711 /*
 712  * Returns 0 on success, negative error value on error.
 713  */
 714 int ustcomm_send_reg_msg(int sock,
 715                 enum ustctl_socket_type type,
 716                 uint32_t bits_per_long,
 717                 uint32_t uint8_t_alignment,
 718                 uint32_t uint16_t_alignment,
 719                 uint32_t uint32_t_alignment,
 720                 uint32_t uint64_t_alignment,
 721                 uint32_t long_alignment)
 722 {
 723         ssize_t len;
 724         struct ustctl_reg_msg reg_msg;
 725
 726         reg_msg.magic = LTTNG_UST_COMM_MAGIC;
 727         reg_msg.major = LTTNG_UST_ABI_MAJOR_VERSION;
 728         reg_msg.minor = LTTNG_UST_ABI_MINOR_VERSION;
 729         reg_msg.pid = getpid();
 730         reg_msg.ppid = getppid();
 731         reg_msg.uid = getuid();
 732         reg_msg.gid = getgid();
 733         reg_msg.bits_per_long = bits_per_long;
 734         reg_msg.uint8_t_alignment = uint8_t_alignment;
 735         reg_msg.uint16_t_alignment = uint16_t_alignment;
 736         reg_msg.uint32_t_alignment = uint32_t_alignment;
 737         reg_msg.uint64_t_alignment = uint64_t_alignment;
 738         reg_msg.long_alignment = long_alignment;
 739         reg_msg.socket_type = type;
 740         lttng_ust_getprocname(reg_msg.name);
 741         memset(reg_msg.padding, 0, sizeof(reg_msg.padding));
 742
 743         len = ustcomm_send_unix_sock(sock, &reg_msg, sizeof(reg_msg));
 744         if (len > 0 && len != sizeof(reg_msg))
 745                 return -EIO;
 746         if (len < 0)
 747                 return len;
 748         return 0;
 749 }
 750
 751 static
 752 ssize_t count_one_type(const struct lttng_type *lt)
 753 {
 754         switch (lt->atype) {
 755         case atype_integer:
 756         case atype_float:
 757         case atype_string:
 758         case atype_enum:
 759         case atype_array:
 760         case atype_sequence:
 761                 return 1;
 762         case atype_struct:
 763                 //TODO: implement non-empty struct.
 764                 return 1;
 765         case atype_dynamic:
 766         {
 767                 const struct lttng_event_field *choices;
 768                 size_t nr_choices;
 769                 int ret;
 770
 771                 ret = lttng_ust_dynamic_type_choices(&nr_choices,
 772                         &choices);
 773                 if (ret)
 774                         return ret;
 775                 /*
 776                  * One field for enum, one field for variant, and
 777                  * one field per choice.
 778                  */
 779                 return count_fields_recursive(nr_choices, choices) + 2;
 780         }
 781         default:
 782                 return -EINVAL;
 783         }
 784         return 0;
 785 }
 786
 787 static
 788 ssize_t count_fields_recursive(size_t nr_fields,
 789                 const struct lttng_event_field *lttng_fields)
 790 {
 791         int i;
 792         ssize_t ret, count = 0;
 793
 794         for (i = 0; i < nr_fields; i++) {
 795                 const struct lttng_event_field *lf;
 796
 797                 lf = &lttng_fields[i];
 798                 /* skip 'nowrite' fields */
 799                 if (lf->nowrite)
 800                         continue;
 801                 ret = count_one_type(&lf->type);
 802                 if (ret < 0)
 803                         return ret;     /* error */
 804                 count += ret;
 805         }
 806         return count;
 807 }
 808
 809 static
 810 ssize_t count_ctx_fields_recursive(size_t nr_fields,
 811                 const struct lttng_ctx_field *lttng_fields)
 812 {
 813         int i;
 814         ssize_t ret, count = 0;
 815
 816         for (i = 0; i < nr_fields; i++) {
 817                 const struct lttng_event_field *lf;
 818
 819                 lf = &lttng_fields[i].event_field;
 820                 /* skip 'nowrite' fields */
 821                 if (lf->nowrite)
 822                         continue;
 823                 ret = count_one_type(&lf->type);
 824                 if (ret < 0)
 825                         return ret;     /* error */
 826                 count += ret;
 827         }
 828         return count;
 829 }
 830
 831 static
 832 int serialize_string_encoding(int32_t *ue,
 833                 enum lttng_string_encodings le)
 834 {
 835         switch (le) {
 836         case lttng_encode_none:
 837                 *ue = ustctl_encode_none;
 838                 break;
 839         case lttng_encode_UTF8:
 840                 *ue = ustctl_encode_UTF8;
 841                 break;
 842         case lttng_encode_ASCII:
 843                 *ue = ustctl_encode_ASCII;
 844                 break;
 845         default:
 846                 return -EINVAL;
 847         }
 848         return 0;
 849 }
 850
 851 static
 852 int serialize_integer_type(struct ustctl_integer_type *uit,
 853                 const struct lttng_integer_type *lit)
 854 {
 855         int32_t encoding;
 856
 857         uit->size = lit->size;
 858         uit->signedness = lit->signedness;
 859         uit->reverse_byte_order = lit->reverse_byte_order;
 860         uit->base = lit->base;
 861         if (serialize_string_encoding(&encoding, lit->encoding))
 862                 return -EINVAL;
 863         uit->encoding = encoding;
 864         uit->alignment = lit->alignment;
 865         return 0;
 866 }
 867
 868 static
 869 int serialize_basic_type(struct lttng_session *session,
 870                 enum ustctl_abstract_types *uatype,
 871                 enum lttng_abstract_types atype,
 872                 union _ustctl_basic_type *ubt,
 873                 const union _lttng_basic_type *lbt)
 874 {
 875         switch (atype) {
 876         case atype_integer:
 877         {
 878                 if (serialize_integer_type(&ubt->integer, &lbt->integer))
 879                         return -EINVAL;
 880                 *uatype = ustctl_atype_integer;
 881                 break;
 882         }
 883         case atype_string:
 884         {
 885                 int32_t encoding;
 886
 887                 if (serialize_string_encoding(&encoding, lbt->string.encoding))
 888                         return -EINVAL;
 889                 ubt->string.encoding = encoding;
 890                 *uatype = ustctl_atype_string;
 891                 break;
 892         }
 893         case atype_float:
 894         {
 895                 struct ustctl_float_type *uft;
 896                 const struct lttng_float_type *lft;
 897
 898                 uft = &ubt->_float;
 899                 lft = &lbt->_float;
 900                 uft->exp_dig = lft->exp_dig;
 901                 uft->mant_dig = lft->mant_dig;
 902                 uft->alignment = lft->alignment;
 903                 uft->reverse_byte_order = lft->reverse_byte_order;
 904                 *uatype = ustctl_atype_float;
 905                 break;
 906         }
 907         case atype_enum:
 908         {
 909                 strncpy(ubt->enumeration.name, lbt->enumeration.desc->name,
 910                                 LTTNG_UST_SYM_NAME_LEN);
 911                 ubt->enumeration.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 912                 if (serialize_integer_type(&ubt->enumeration.container_type,
 913                                 &lbt->enumeration.container_type))
 914                         return -EINVAL;
 915                 if (session) {
 916                         const struct lttng_enum *_enum;
 917
 918                         _enum = lttng_ust_enum_get_from_desc(session, lbt->enumeration.desc);
 919                         if (!_enum)
 920                                 return -EINVAL;
 921                         ubt->enumeration.id = _enum->id;
 922                 } else {
 923                         ubt->enumeration.id = -1ULL;
 924                 }
 925                 *uatype = ustctl_atype_enum;
 926                 break;
 927         }
 928         case atype_array:
 929         case atype_sequence:
 930         default:
 931                 return -EINVAL;
 932         }
 933         return 0;
 934 }
 935
 936 static
 937 int serialize_dynamic_type(struct lttng_session *session,
 938                 struct ustctl_field *fields, size_t *iter_output,
 939                 const struct lttng_event_field *lf)
 940 {
 941         const struct lttng_event_field *choices;
 942         char tag_field_name[LTTNG_UST_SYM_NAME_LEN];
 943         const struct lttng_type *tag_type;
 944         const struct lttng_event_field *tag_field_generic;
 945         struct lttng_event_field tag_field = {
 946                 .name = tag_field_name,
 947                 .nowrite = 0,
 948         };
 949         struct ustctl_field *uf;
 950         size_t nr_choices, i;
 951         int ret;
 952
 953         tag_field_generic = lttng_ust_dynamic_type_tag_field();
 954         tag_type = &tag_field_generic->type;
 955
 956         /* Serialize enum field. */
 957         strncpy(tag_field_name, lf->name, LTTNG_UST_SYM_NAME_LEN);
 958         tag_field_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 959         strncat(tag_field_name,
 960                 "_tag",
 961                 LTTNG_UST_SYM_NAME_LEN - strlen(tag_field_name) - 1);
 962         tag_field.type = *tag_type;
 963         ret = serialize_one_field(session, fields, iter_output,
 964                 &tag_field);
 965         if (ret)
 966                 return ret;
 967
 968         /* Serialize variant field. */
 969         uf = &fields[*iter_output];
 970         ret = lttng_ust_dynamic_type_choices(&nr_choices, &choices);
 971         if (ret)
 972                 return ret;
 973
 974         strncpy(uf->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
 975         uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 976         uf->type.atype = ustctl_atype_variant;
 977         uf->type.u.variant.nr_choices = nr_choices;
 978         strncpy(uf->type.u.variant.tag_name,
 979                 tag_field_name,
 980                 LTTNG_UST_SYM_NAME_LEN);
 981         uf->type.u.variant.tag_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 982         (*iter_output)++;
 983
 984         /* Serialize choice fields after variant. */
 985         for (i = 0; i < nr_choices; i++) {
 986                 ret = serialize_one_field(session, fields,
 987                         iter_output, &choices[i]);
 988                 if (ret)
 989                         return ret;
 990         }
 991         return 0;
 992 }
 993
 994 static
 995 int serialize_one_field(struct lttng_session *session,
 996                 struct ustctl_field *fields, size_t *iter_output,
 997                 const struct lttng_event_field *lf)
 998 {
 999         const struct lttng_type *lt = &lf->type;
1000         int ret;
1001
1002         /* skip 'nowrite' fields */
1003         if (lf->nowrite)
1004                 return 0;
1005
1006         switch (lt->atype) {
1007         case atype_integer:
1008         case atype_float:
1009         case atype_string:
1010         case atype_enum:
1011         {
1012                 struct ustctl_field *uf = &fields[*iter_output];
1013                 struct ustctl_type *ut = &uf->type;
1014                 enum ustctl_abstract_types atype;
1015
1016                 strncpy(uf->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
1017                 uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1018                 ret = serialize_basic_type(session, &atype, lt->atype,
1019                         &ut->u.basic, &lt->u.basic);
1020                 if (ret)
1021                         return ret;
1022                 ut->atype = atype;
1023                 (*iter_output)++;
1024                 break;
1025         }
1026         case atype_array:
1027         {
1028                 struct ustctl_field *uf = &fields[*iter_output];
1029                 struct ustctl_type *ut = &uf->type;
1030                 struct ustctl_basic_type *ubt;
1031                 const struct lttng_basic_type *lbt;
1032                 enum ustctl_abstract_types atype;
1033
1034                 strncpy(uf->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
1035                 uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1036                 uf->type.atype = ustctl_atype_array;
1037                 ubt = &ut->u.array.elem_type;
1038                 lbt = &lt->u.array.elem_type;
1039                 ut->u.array.length = lt->u.array.length;
1040                 ret = serialize_basic_type(session, &atype, lbt->atype,
1041                         &ubt->u.basic, &lbt->u.basic);
1042                 if (ret)
1043                         return -EINVAL;
1044                 ubt->atype = atype;
1045                 ut->atype = ustctl_atype_array;
1046                 (*iter_output)++;
1047                 break;
1048         }
1049         case atype_sequence:
1050         {
1051                 struct ustctl_field *uf = &fields[*iter_output];
1052                 struct ustctl_type *ut = &uf->type;
1053                 struct ustctl_basic_type *ubt;
1054                 const struct lttng_basic_type *lbt;
1055                 enum ustctl_abstract_types atype;
1056                 int ret;
1057
1058                 strncpy(uf->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
1059                 uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1060                 uf->type.atype = ustctl_atype_sequence;
1061                 ubt = &ut->u.sequence.length_type;
1062                 lbt = &lt->u.sequence.length_type;
1063                 ret = serialize_basic_type(session, &atype, lbt->atype,
1064                         &ubt->u.basic, &lbt->u.basic);
1065                 if (ret)
1066                         return -EINVAL;
1067                 ubt->atype = atype;
1068                 ubt = &ut->u.sequence.elem_type;
1069                 lbt = &lt->u.sequence.elem_type;
1070                 ret = serialize_basic_type(session, &atype, lbt->atype,
1071                         &ubt->u.basic, &lbt->u.basic);
1072                 if (ret)
1073                         return -EINVAL;
1074                 ubt->atype = atype;
1075                 ut->atype = ustctl_atype_sequence;
1076                 (*iter_output)++;
1077                 break;
1078         }
1079         case atype_dynamic:
1080         {
1081                 ret = serialize_dynamic_type(session, fields, iter_output, lf);
1082                 if (ret)
1083                         return -EINVAL;
1084                 break;
1085         }
1086         case atype_struct:
1087         {
1088                 struct ustctl_field *uf = &fields[*iter_output];
1089
1090                 /*
1091                  * TODO: add support for non-empty struct.
1092                  */
1093                 if (lf->type.u._struct.nr_fields != 0) {
1094                         return -EINVAL;
1095                 }
1096                 strncpy(uf->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
1097                 uf->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1098                 uf->type.atype = ustctl_atype_struct;
1099                 uf->type.u._struct.nr_fields = 0;
1100                 (*iter_output)++;
1101                 break;
1102         }
1103         default:
1104                 return -EINVAL;
1105         }
1106         return 0;
1107 }
1108
1109 static
1110 int serialize_fields(struct lttng_session *session,
1111                 size_t *_nr_write_fields,
1112                 struct ustctl_field **ustctl_fields,
1113                 size_t nr_fields,
1114                 const struct lttng_event_field *lttng_fields)
1115 {
1116         struct ustctl_field *fields;
1117         int ret;
1118         size_t i, iter_output = 0;
1119         ssize_t nr_write_fields;
1120
1121         nr_write_fields = count_fields_recursive(nr_fields, lttng_fields);
1122         if (nr_write_fields < 0) {
1123                 return (int) nr_write_fields;
1124         }
1125
1126         fields = zmalloc(nr_write_fields * sizeof(*fields));
1127         if (!fields)
1128                 return -ENOMEM;
1129
1130         for (i = 0; i < nr_fields; i++) {
1131                 ret = serialize_one_field(session, fields, &iter_output,
1132                                 &lttng_fields[i]);
1133                 if (ret)
1134                         goto error_type;
1135         }
1136
1137         *_nr_write_fields = nr_write_fields;
1138         *ustctl_fields = fields;
1139         return 0;
1140
1141 error_type:
1142         free(fields);
1143         return ret;
1144 }
1145
1146 static
1147 int serialize_entries(struct ustctl_enum_entry **_entries,
1148                 size_t nr_entries,
1149                 const struct lttng_enum_entry *lttng_entries)
1150 {
1151         struct ustctl_enum_entry *entries;
1152         int i;
1153
1154         /* Serialize the entries */
1155         entries = zmalloc(nr_entries * sizeof(*entries));
1156         if (!entries)
1157                 return -ENOMEM;
1158         for (i = 0; i < nr_entries; i++) {
1159                 struct ustctl_enum_entry *uentry;
1160                 const struct lttng_enum_entry *lentry;
1161
1162                 uentry = &entries[i];
1163                 lentry = &lttng_entries[i];
1164
1165                 uentry->start.value = lentry->start.value;
1166                 uentry->start.signedness = lentry->start.signedness;
1167                 uentry->end.value = lentry->end.value;
1168                 uentry->end.signedness = lentry->end.signedness;
1169                 strncpy(uentry->string, lentry->string, LTTNG_UST_SYM_NAME_LEN);
1170                 uentry->string[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1171
1172                 if (lentry->u.extra.options & LTTNG_ENUM_ENTRY_OPTION_IS_AUTO) {
1173                         uentry->u.extra.options |=
1174                                 USTCTL_UST_ENUM_ENTRY_OPTION_IS_AUTO;
1175                 }
1176         }
1177         *_entries = entries;
1178         return 0;
1179 }
1180
1181 static
1182 int serialize_ctx_fields(struct lttng_session *session,
1183                 size_t *_nr_write_fields,
1184                 struct ustctl_field **ustctl_fields,
1185                 size_t nr_fields,
1186                 const struct lttng_ctx_field *lttng_fields)
1187 {
1188         struct ustctl_field *fields;
1189         int ret;
1190         size_t i, iter_output = 0;
1191         ssize_t nr_write_fields;
1192
1193         nr_write_fields = count_ctx_fields_recursive(nr_fields,
1194                         lttng_fields);
1195         if (nr_write_fields < 0) {
1196                 return (int) nr_write_fields;
1197         }
1198
1199         fields = zmalloc(nr_write_fields * sizeof(*fields));
1200         if (!fields)
1201                 return -ENOMEM;
1202
1203         for (i = 0; i < nr_fields; i++) {
1204                 ret = serialize_one_field(session, fields, &iter_output,
1205                                 &lttng_fields[i].event_field);
1206                 if (ret)
1207                         goto error_type;
1208         }
1209
1210         *_nr_write_fields = nr_write_fields;
1211         *ustctl_fields = fields;
1212         return 0;
1213
1214 error_type:
1215         free(fields);
1216         return ret;
1217 }
1218
1219 /*
1220  * Returns 0 on success, negative error value on error.
1221  */
1222 int ustcomm_register_event(int sock,
1223         struct lttng_session *session,
1224         int session_objd,               /* session descriptor */
1225         int channel_objd,               /* channel descriptor */
1226         const char *event_name,         /* event name (input) */
1227         int loglevel,
1228         const char *signature,          /* event signature (input) */
1229         size_t nr_fields,               /* fields */
1230         const struct lttng_event_field *lttng_fields,
1231         const char *model_emf_uri,
1232         uint32_t *id)                   /* event id (output) */
1233 {
1234         ssize_t len;
1235         struct {
1236                 struct ustcomm_notify_hdr header;
1237                 struct ustcomm_notify_event_msg m;
1238         } msg;
1239         struct {
1240                 struct ustcomm_notify_hdr header;
1241                 struct ustcomm_notify_event_reply r;
1242         } reply;
1243         size_t signature_len, fields_len, model_emf_uri_len;
1244         struct ustctl_field *fields = NULL;
1245         size_t nr_write_fields = 0;
1246         int ret;
1247
1248         memset(&msg, 0, sizeof(msg));
1249         msg.header.notify_cmd = USTCTL_NOTIFY_CMD_EVENT;
1250         msg.m.session_objd = session_objd;
1251         msg.m.channel_objd = channel_objd;
1252         strncpy(msg.m.event_name, event_name, LTTNG_UST_SYM_NAME_LEN);
1253         msg.m.event_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1254         msg.m.loglevel = loglevel;
1255         signature_len = strlen(signature) + 1;
1256         msg.m.signature_len = signature_len;
1257
1258         /* Calculate fields len, serialize fields. */
1259         if (nr_fields > 0) {
1260                 ret = serialize_fields(session, &nr_write_fields, &fields,
1261                                 nr_fields, lttng_fields);
1262                 if (ret)
1263                         return ret;
1264         }
1265
1266         fields_len = sizeof(*fields) * nr_write_fields;
1267         msg.m.fields_len = fields_len;
1268         if (model_emf_uri) {
1269                 model_emf_uri_len = strlen(model_emf_uri) + 1;
1270         } else {
1271                 model_emf_uri_len = 0;
1272         }
1273         msg.m.model_emf_uri_len = model_emf_uri_len;
1274
1275         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1276         if (len > 0 && len != sizeof(msg)) {
1277                 ret = -EIO;
1278                 goto error_fields;
1279         }
1280         if (len < 0) {
1281                 ret = len;
1282                 goto error_fields;
1283         }
1284
1285         /* send signature */
1286         len = ustcomm_send_unix_sock(sock, signature, signature_len);
1287         if (len > 0 && len != signature_len) {
1288                 ret = -EIO;
1289                 goto error_fields;
1290         }
1291         if (len < 0) {
1292                 ret = len;
1293                 goto error_fields;
1294         }
1295
1296         /* send fields */
1297         if (fields_len > 0) {
1298                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
1299                 if (len > 0 && len != fields_len) {
1300                         ret = -EIO;
1301                         goto error_fields;
1302                 }
1303                 if (len < 0) {
1304                         ret = len;
1305                         goto error_fields;
1306                 }
1307         }
1308         free(fields);
1309
1310         if (model_emf_uri_len) {
1311                 /* send model_emf_uri */
1312                 len = ustcomm_send_unix_sock(sock, model_emf_uri,
1313                                 model_emf_uri_len);
1314                 if (len > 0 && len != model_emf_uri_len) {
1315                         return -EIO;
1316                 }
1317                 if (len < 0) {
1318                         return len;
1319                 }
1320         }
1321
1322         /* receive reply */
1323         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1324         switch (len) {
1325         case 0: /* orderly shutdown */
1326                 return -EPIPE;
1327         case sizeof(reply):
1328                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1329                         ERR("Unexpected result message command "
1330                                 "expected: %u vs received: %u\n",
1331                                 msg.header.notify_cmd, reply.header.notify_cmd);
1332                         return -EINVAL;
1333                 }
1334                 if (reply.r.ret_code > 0)
1335                         return -EINVAL;
1336                 if (reply.r.ret_code < 0)
1337                         return reply.r.ret_code;
1338                 *id = reply.r.event_id;
1339                 DBG("Sent register event notification for name \"%s\": ret_code %d, event_id %u\n",
1340                         event_name, reply.r.ret_code, reply.r.event_id);
1341                 return 0;
1342         default:
1343                 if (len < 0) {
1344                         /* Transport level error */
1345                         if (errno == EPIPE || errno == ECONNRESET)
1346                                 len = -errno;
1347                         return len;
1348                 } else {
1349                         ERR("incorrect message size: %zd\n", len);
1350                         return len;
1351                 }
1352         }
1353         /* Unreached. */
1354
1355         /* Error path only. */
1356 error_fields:
1357         free(fields);
1358         return ret;
1359 }
1360
1361 /*
1362  * Returns 0 on success, negative error value on error.
1363  * Returns -EPIPE or -ECONNRESET if other end has hung up.
1364  */
1365 int ustcomm_register_enum(int sock,
1366         int session_objd,               /* session descriptor */
1367         const char *enum_name,          /* enum name (input) */
1368         size_t nr_entries,              /* entries */
1369         const struct lttng_enum_entry *lttng_entries,
1370         uint64_t *id)
1371 {
1372         ssize_t len;
1373         struct {
1374                 struct ustcomm_notify_hdr header;
1375                 struct ustcomm_notify_enum_msg m;
1376         } msg;
1377         struct {
1378                 struct ustcomm_notify_hdr header;
1379                 struct ustcomm_notify_enum_reply r;
1380         } reply;
1381         size_t entries_len;
1382         struct ustctl_enum_entry *entries = NULL;
1383         int ret;
1384
1385         memset(&msg, 0, sizeof(msg));
1386         msg.header.notify_cmd = USTCTL_NOTIFY_CMD_ENUM;
1387         msg.m.session_objd = session_objd;
1388         strncpy(msg.m.enum_name, enum_name, LTTNG_UST_SYM_NAME_LEN);
1389         msg.m.enum_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
1390
1391         /* Calculate entries len, serialize entries. */
1392         if (nr_entries > 0) {
1393                 ret = serialize_entries(&entries,
1394                                 nr_entries, lttng_entries);
1395                 if (ret)
1396                         return ret;
1397         }
1398
1399         entries_len = sizeof(*entries) * nr_entries;
1400         msg.m.entries_len = entries_len;
1401
1402         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1403         if (len > 0 && len != sizeof(msg)) {
1404                 ret = -EIO;
1405                 goto error_entries;
1406         }
1407         if (len < 0) {
1408                 ret = len;
1409                 goto error_entries;
1410         }
1411
1412         /* send entries */
1413         if (entries_len > 0) {
1414                 len = ustcomm_send_unix_sock(sock, entries, entries_len);
1415                 if (len > 0 && len != entries_len) {
1416                         ret = -EIO;
1417                         goto error_entries;
1418                 }
1419                 if (len < 0) {
1420                         ret = len;
1421                         goto error_entries;
1422                 }
1423         }
1424         free(entries);
1425         entries = NULL;
1426
1427         /* receive reply */
1428         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1429         switch (len) {
1430         case 0: /* orderly shutdown */
1431                 return -EPIPE;
1432         case sizeof(reply):
1433                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1434                         ERR("Unexpected result message command "
1435                                 "expected: %u vs received: %u\n",
1436                                 msg.header.notify_cmd, reply.header.notify_cmd);
1437                         return -EINVAL;
1438                 }
1439                 if (reply.r.ret_code > 0)
1440                         return -EINVAL;
1441                 if (reply.r.ret_code < 0)
1442                         return reply.r.ret_code;
1443                 *id = reply.r.enum_id;
1444                 DBG("Sent register enum notification for name \"%s\": ret_code %d\n",
1445                         enum_name, reply.r.ret_code);
1446                 return 0;
1447         default:
1448                 if (len < 0) {
1449                         /* Transport level error */
1450                         if (errno == EPIPE || errno == ECONNRESET)
1451                                 len = -errno;
1452                         return len;
1453                 } else {
1454                         ERR("incorrect message size: %zd\n", len);
1455                         return len;
1456                 }
1457         }
1458         return ret;
1459
1460 error_entries:
1461         free(entries);
1462         return ret;
1463 }
1464
1465 /*
1466  * Returns 0 on success, negative error value on error.
1467  * Returns -EPIPE or -ECONNRESET if other end has hung up.
1468  */
1469 int ustcomm_register_channel(int sock,
1470         struct lttng_session *session,
1471         int session_objd,               /* session descriptor */
1472         int channel_objd,               /* channel descriptor */
1473         size_t nr_ctx_fields,
1474         const struct lttng_ctx_field *ctx_fields,
1475         uint32_t *chan_id,              /* channel id (output) */
1476         int *header_type)               /* header type (output) */
1477 {
1478         ssize_t len;
1479         struct {
1480                 struct ustcomm_notify_hdr header;
1481                 struct ustcomm_notify_channel_msg m;
1482         } msg;
1483         struct {
1484                 struct ustcomm_notify_hdr header;
1485                 struct ustcomm_notify_channel_reply r;
1486         } reply;
1487         size_t fields_len;
1488         struct ustctl_field *fields = NULL;
1489         int ret;
1490         size_t nr_write_fields = 0;
1491
1492         memset(&msg, 0, sizeof(msg));
1493         msg.header.notify_cmd = USTCTL_NOTIFY_CMD_CHANNEL;
1494         msg.m.session_objd = session_objd;
1495         msg.m.channel_objd = channel_objd;
1496
1497         /* Calculate fields len, serialize fields. */
1498         if (nr_ctx_fields > 0) {
1499                 ret = serialize_ctx_fields(session, &nr_write_fields, &fields,
1500                                 nr_ctx_fields, ctx_fields);
1501                 if (ret)
1502                         return ret;
1503         }
1504
1505         fields_len = sizeof(*fields) * nr_write_fields;
1506         msg.m.ctx_fields_len = fields_len;
1507         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1508         if (len > 0 && len != sizeof(msg)) {
1509                 free(fields);
1510                 return -EIO;
1511         }
1512         if (len < 0) {
1513                 free(fields);
1514                 return len;
1515         }
1516
1517         /* send fields */
1518         if (fields_len > 0) {
1519                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
1520                 free(fields);
1521                 if (len > 0 && len != fields_len) {
1522                         return -EIO;
1523                 }
1524                 if (len < 0) {
1525                         return len;
1526                 }
1527         } else {
1528                 free(fields);
1529         }
1530
1531         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1532         switch (len) {
1533         case 0: /* orderly shutdown */
1534                 return -EPIPE;
1535         case sizeof(reply):
1536                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1537                         ERR("Unexpected result message command "
1538                                 "expected: %u vs received: %u\n",
1539                                 msg.header.notify_cmd, reply.header.notify_cmd);
1540                         return -EINVAL;
1541                 }
1542                 if (reply.r.ret_code > 0)
1543                         return -EINVAL;
1544                 if (reply.r.ret_code < 0)
1545                         return reply.r.ret_code;
1546                 *chan_id = reply.r.chan_id;
1547                 switch (reply.r.header_type) {
1548                 case 1:
1549                 case 2:
1550                         *header_type = reply.r.header_type;
1551                         break;
1552                 default:
1553                         ERR("Unexpected channel header type %u\n",
1554                                 reply.r.header_type);
1555                         return -EINVAL;
1556                 }
1557                 DBG("Sent register channel notification: chan_id %d, header_type %d\n",
1558                         reply.r.chan_id, reply.r.header_type);
1559                 return 0;
1560         default:
1561                 if (len < 0) {
1562                         /* Transport level error */
1563                         if (errno == EPIPE || errno == ECONNRESET)
1564                                 len = -errno;
1565                         return len;
1566                 } else {
1567                         ERR("incorrect message size: %zd\n", len);
1568                         return len;
1569                 }
1570         }
1571 }
1572
1573 /*
1574  * Set socket reciving timeout.
1575  */
1576 int ustcomm_setsockopt_rcv_timeout(int sock, unsigned int msec)
1577 {
1578         int ret;
1579         struct timeval tv;
1580
1581         tv.tv_sec = msec / 1000;
1582         tv.tv_usec = (msec * 1000 % 1000000);
1583
1584         ret = setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
1585         if (ret < 0) {
1586                 PERROR("setsockopt SO_RCVTIMEO");
1587                 ret = -errno;
1588         }
1589
1590         return ret;
1591 }
1592
1593 /*
1594  * Set socket sending timeout.
1595  */
1596 int ustcomm_setsockopt_snd_timeout(int sock, unsigned int msec)
1597 {
1598         int ret;
1599         struct timeval tv;
1600
1601         tv.tv_sec = msec / 1000;
1602         tv.tv_usec = (msec * 1000) % 1000000;
1603
1604         ret = setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
1605         if (ret < 0) {
1606                 PERROR("setsockopt SO_SNDTIMEO");
1607                 ret = -errno;
1608         }
1609
1610         return ret;
1611 }