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