src/common/ustcomm.c

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   5  * Copyright (C) 2011-2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  */
   7
   8 #include <limits.h>
   9 #include <stdint.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/socket.h>
  14 #include <sys/stat.h>
  15 #include <sys/types.h>
  16 #include <sys/un.h>
  17 #include <unistd.h>
  18 #include <assert.h>
  19 #include <errno.h>
  20 #include <fcntl.h>
  21
  22 #include <lttng/ust-ctl.h>
  23 #include "common/ustcomm.h"
  24 #include "common/ust-fd.h"
  25 #include "common/macros.h"
  26 #include "common/dynamic-type.h"
  27 #include "common/logging.h"
  28
  29 #include "common/events.h"
  30 #include "common/compat/pthread.h"
  31
  32 #define USTCOMM_MAX_SEND_FDS    4
  33
  34 static
  35 ssize_t count_fields_recursive(size_t nr_fields,
  36                 const struct lttng_ust_event_field * const *lttng_fields);
  37 static
  38 int serialize_one_field(struct lttng_ust_session *session,
  39                 struct lttng_ust_ctl_field *fields, size_t *iter_output,
  40                 const struct lttng_ust_event_field *lf,
  41                 const char **prev_field_name);
  42 static
  43 int serialize_fields(struct lttng_ust_session *session,
  44                 struct lttng_ust_ctl_field *lttng_ust_ctl_fields,
  45                 size_t *iter_output, size_t nr_lttng_fields,
  46                 const struct lttng_ust_event_field * const *lttng_fields);
  47
  48 /*
  49  * ustcomm_connect_unix_sock
  50  *
  51  * Connect to unix socket using the path name.
  52  *
  53  * Caller handles FD tracker.
  54  */
  55 int ustcomm_connect_unix_sock(const char *pathname, long timeout)
  56 {
  57         struct sockaddr_un sun;
  58         int fd, ret;
  59
  60         /*
  61          * libust threads require the close-on-exec flag for all
  62          * resources so it does not leak file descriptors upon exec.
  63          * SOCK_CLOEXEC is not used since it is linux specific.
  64          */
  65         fd = socket(PF_UNIX, SOCK_STREAM, 0);
  66         if (fd < 0) {
  67                 PERROR("socket");
  68                 ret = -errno;
  69                 goto error;
  70         }
  71         if (timeout >= 0) {
  72                 /* Give at least 10ms. */
  73                 if (timeout < 10)
  74                         timeout = 10;
  75                 ret = ustcomm_setsockopt_snd_timeout(fd, timeout);
  76                 if (ret < 0) {
  77                         WARN("Error setting connect socket send timeout");
  78                 }
  79         }
  80         ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
  81         if (ret < 0) {
  82                 PERROR("fcntl");
  83                 ret = -errno;
  84                 goto error_fcntl;
  85         }
  86
  87         memset(&sun, 0, sizeof(sun));
  88         sun.sun_family = AF_UNIX;
  89         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
  90         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
  91
  92         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
  93         if (ret < 0) {
  94                 /*
  95                  * Don't print message on connect ENOENT error, because
  96                  * connect is used in normal execution to detect if
  97                  * sessiond is alive. ENOENT is when the unix socket
  98                  * file does not exist, and ECONNREFUSED is when the
  99                  * file exists but no sessiond is listening.
 100                  */
 101                 if (errno != ECONNREFUSED && errno != ECONNRESET
 102                                 && errno != ENOENT && errno != EACCES)
 103                         PERROR("connect");
 104                 ret = -errno;
 105                 if (ret == -ECONNREFUSED || ret == -ECONNRESET)
 106                         ret = -EPIPE;
 107                 goto error_connect;
 108         }
 109
 110         return fd;
 111
 112 error_connect:
 113 error_fcntl:
 114         {
 115                 int closeret;
 116
 117                 closeret = close(fd);
 118                 if (closeret)
 119                         PERROR("close");
 120         }
 121 error:
 122         return ret;
 123 }
 124
 125 /*
 126  * ustcomm_accept_unix_sock
 127  *
 128  * Do an accept(2) on the sock and return the
 129  * new file descriptor. The socket MUST be bind(2) before.
 130  */
 131 int ustcomm_accept_unix_sock(int sock)
 132 {
 133         int new_fd;
 134         struct sockaddr_un sun;
 135         socklen_t len = 0;
 136
 137         /* Blocking call */
 138         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 139         if (new_fd < 0) {
 140                 if (errno != ECONNABORTED)
 141                         PERROR("accept");
 142                 new_fd = -errno;
 143                 if (new_fd == -ECONNABORTED)
 144                         new_fd = -EPIPE;
 145         }
 146         return new_fd;
 147 }
 148
 149 /*
 150  * ustcomm_create_unix_sock
 151  *
 152  * Creates a AF_UNIX local socket using pathname
 153  * bind the socket upon creation and return the fd.
 154  */
 155 int ustcomm_create_unix_sock(const char *pathname)
 156 {
 157         struct sockaddr_un sun;
 158         int fd, ret;
 159
 160         /* Create server socket */
 161         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 162                 PERROR("socket");
 163                 ret = -errno;
 164                 goto error;
 165         }
 166
 167         memset(&sun, 0, sizeof(sun));
 168         sun.sun_family = AF_UNIX;
 169         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 170         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 171
 172         /* Unlink the old file if present */
 173         (void) unlink(pathname);
 174         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 175         if (ret < 0) {
 176                 PERROR("bind");
 177                 ret = -errno;
 178                 goto error_close;
 179         }
 180
 181         return fd;
 182
 183 error_close:
 184         {
 185                 int closeret;
 186
 187                 closeret = close(fd);
 188                 if (closeret) {
 189                         PERROR("close");
 190                 }
 191         }
 192 error:
 193         return ret;
 194 }
 195
 196 /*
 197  * ustcomm_listen_unix_sock
 198  *
 199  * Make the socket listen using LTTNG_UST_COMM_MAX_LISTEN.
 200  */
 201 int ustcomm_listen_unix_sock(int sock)
 202 {
 203         int ret;
 204
 205         ret = listen(sock, LTTNG_UST_COMM_MAX_LISTEN);
 206         if (ret < 0) {
 207                 ret = -errno;
 208                 PERROR("listen");
 209         }
 210
 211         return ret;
 212 }
 213
 214 /*
 215  * ustcomm_close_unix_sock
 216  *
 217  * Close unix socket.
 218  *
 219  * Handles fd tracker internally.
 220  */
 221 int ustcomm_close_unix_sock(int sock)
 222 {
 223         int ret;
 224
 225         lttng_ust_lock_fd_tracker();
 226         ret = close(sock);
 227         if (!ret) {
 228                 lttng_ust_delete_fd_from_tracker(sock);
 229         } else {
 230                 PERROR("close");
 231                 ret = -errno;
 232         }
 233         lttng_ust_unlock_fd_tracker();
 234
 235         return ret;
 236 }
 237
 238 /*
 239  * ustcomm_shutdown_unix_sock
 240  *
 241  * Shutdown unix socket. Keeps the file descriptor open, but shutdown
 242  * communication.
 243  */
 244 int ustcomm_shutdown_unix_sock(int sock)
 245 {
 246         int ret;
 247
 248         ret = shutdown(sock, SHUT_RDWR);
 249         if (ret) {
 250                 PERROR("Socket shutdown error");
 251                 ret = -errno;
 252         }
 253         return ret;
 254 }
 255
 256 /*
 257  * ustcomm_recv_unix_sock
 258  *
 259  * Receive data of size len in put that data into
 260  * the buf param. Using recvmsg API.
 261  * Return the size of received data.
 262  * Return 0 on orderly shutdown.
 263  */
 264 ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len)
 265 {
 266         struct msghdr msg;
 267         struct iovec iov[1];
 268         ssize_t ret = -1;
 269         size_t len_last;
 270
 271         memset(&msg, 0, sizeof(msg));
 272
 273         iov[0].iov_base = buf;
 274         iov[0].iov_len = len;
 275         msg.msg_iov = iov;
 276         msg.msg_iovlen = 1;
 277
 278         do {
 279                 len_last = iov[0].iov_len;
 280                 ret = recvmsg(sock, &msg, 0);
 281                 if (ret > 0) {
 282                         iov[0].iov_base += ret;
 283                         iov[0].iov_len -= ret;
 284                         assert(ret <= len_last);
 285                 }
 286         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 287
 288         if (ret < 0) {
 289                 if (errno != EPIPE && errno != ECONNRESET && errno != ECONNREFUSED)
 290                         PERROR("recvmsg");
 291                 ret = -errno;
 292                 if (ret == -ECONNRESET || ret == -ECONNREFUSED)
 293                         ret = -EPIPE;
 294
 295                 (void) ustcomm_shutdown_unix_sock(sock);
 296         } else if (ret > 0) {
 297                 ret = len;
 298         }
 299         /* ret = 0 means an orderly shutdown. */
 300
 301         return ret;
 302 }
 303
 304 /*
 305  * ustcomm_send_unix_sock
 306  *
 307  * Send buf data of size len. Using sendmsg API.
 308  * Return the size of sent data.
 309  */
 310 ssize_t ustcomm_send_unix_sock(int sock, const void *buf, size_t len)
 311 {
 312         struct msghdr msg;
 313         struct iovec iov[1];
 314         ssize_t ret;
 315
 316         memset(&msg, 0, sizeof(msg));
 317
 318         iov[0].iov_base = (void *) buf;
 319         iov[0].iov_len = len;
 320         msg.msg_iov = iov;
 321         msg.msg_iovlen = 1;
 322
 323         /*
 324          * Using the MSG_NOSIGNAL when sending data from sessiond to
 325          * libust, so libust does not receive an unhandled SIGPIPE or
 326          * SIGURG. The sessiond receiver side can be made more resilient
 327          * by ignoring SIGPIPE, but we don't have this luxury on the
 328          * libust side.
 329          */
 330         do {
 331                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 332         } while (ret < 0 && errno == EINTR);
 333
 334         if (ret < 0) {
 335                 if (errno != EPIPE && errno != ECONNRESET)
 336                         PERROR("sendmsg");
 337                 ret = -errno;
 338                 if (ret == -ECONNRESET)
 339                         ret = -EPIPE;
 340
 341                 (void) ustcomm_shutdown_unix_sock(sock);
 342         }
 343
 344         return ret;
 345 }
 346
 347 /*
 348  * Send a message accompanied by fd(s) over a unix socket.
 349  *
 350  * Returns the size of data sent, or negative error value.
 351  */
 352 ssize_t ustcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 353 {
 354         struct msghdr msg;
 355         struct cmsghdr *cmptr;
 356         struct iovec iov[1];
 357         ssize_t ret = -1;
 358         unsigned int sizeof_fds = nb_fd * sizeof(int);
 359         char tmp[CMSG_SPACE(sizeof_fds)];
 360         char dummy = 0;
 361
 362         memset(&msg, 0, sizeof(msg));
 363         memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
 364
 365         if (nb_fd > USTCOMM_MAX_SEND_FDS)
 366                 return -EINVAL;
 367
 368         msg.msg_control = (caddr_t)tmp;
 369         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 370
 371         cmptr = CMSG_FIRSTHDR(&msg);
 372         if (!cmptr)
 373                 return -EINVAL;
 374         cmptr->cmsg_level = SOL_SOCKET;
 375         cmptr->cmsg_type = SCM_RIGHTS;
 376         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 377         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 378         /* Sum of the length of all control messages in the buffer: */
 379         msg.msg_controllen = cmptr->cmsg_len;
 380
 381         iov[0].iov_base = &dummy;
 382         iov[0].iov_len = 1;
 383         msg.msg_iov = iov;
 384         msg.msg_iovlen = 1;
 385
 386         do {
 387                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 388         } while (ret < 0 && errno == EINTR);
 389         if (ret < 0) {
 390                 /*
 391                  * We consider EPIPE and ECONNRESET as expected.
 392                  */
 393                 if (errno != EPIPE && errno != ECONNRESET) {
 394                         PERROR("sendmsg");
 395                 }
 396                 ret = -errno;
 397                 if (ret == -ECONNRESET)
 398                         ret = -EPIPE;
 399         }
 400         return ret;
 401 }
 402
 403 /*
 404  * Recv a message accompanied by fd(s) from a unix socket.
 405  *
 406  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 407  * actually received in nb_fd.
 408  * Returns -EPIPE on orderly shutdown.
 409  */
 410 ssize_t ustcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 411 {
 412         struct iovec iov[1];
 413         ssize_t ret = 0;
 414         struct cmsghdr *cmsg;
 415         size_t sizeof_fds = nb_fd * sizeof(int);
 416         char recv_fd[CMSG_SPACE(sizeof_fds)];
 417         struct msghdr msg;
 418         char dummy;
 419         int i;
 420
 421         memset(&msg, 0, sizeof(msg));
 422
 423         /* Prepare to receive the structures */
 424         iov[0].iov_base = &dummy;
 425         iov[0].iov_len = 1;
 426         msg.msg_iov = iov;
 427         msg.msg_iovlen = 1;
 428         msg.msg_control = recv_fd;
 429         msg.msg_controllen = sizeof(recv_fd);
 430
 431         do {
 432                 ret = recvmsg(sock, &msg, 0);
 433         } while (ret < 0 && errno == EINTR);
 434         if (ret < 0) {
 435                 if (errno != EPIPE && errno != ECONNRESET) {
 436                         PERROR("recvmsg fds");
 437                 }
 438                 ret = -errno;
 439                 if (ret == -ECONNRESET)
 440                         ret = -EPIPE;
 441                 goto end;
 442         }
 443         if (ret == 0) {
 444                 /* orderly shutdown */
 445                 ret = -EPIPE;
 446                 goto end;
 447         }
 448         if (ret != 1) {
 449                 ERR("Error: Received %zd bytes, expected %d\n",
 450                                 ret, 1);
 451                 goto end;
 452         }
 453         if (msg.msg_flags & MSG_CTRUNC) {
 454                 ERR("Error: Control message truncated.\n");
 455                 ret = -1;
 456                 goto end;
 457         }
 458         cmsg = CMSG_FIRSTHDR(&msg);
 459         if (!cmsg) {
 460                 ERR("Error: Invalid control message header\n");
 461                 ret = -1;
 462                 goto end;
 463         }
 464         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 465                 ERR("Didn't received any fd\n");
 466                 ret = -1;
 467                 goto end;
 468         }
 469         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 470                 ERR("Error: Received %zu bytes of ancillary data, expected %zu\n",
 471                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 472                 ret = -1;
 473                 goto end;
 474         }
 475
 476         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 477
 478         /* Set FD_CLOEXEC */
 479         for (i = 0; i < nb_fd; i++) {
 480                 ret = fcntl(fds[i], F_SETFD, FD_CLOEXEC);
 481                 if (ret < 0) {
 482                         PERROR("fcntl failed to set FD_CLOEXEC on fd %d",
 483                                fds[i]);
 484                 }
 485         }
 486
 487         ret = nb_fd;
 488 end:
 489         return ret;
 490 }
 491
 492 int ustcomm_send_app_msg(int sock, struct ustcomm_ust_msg *lum)
 493 {
 494         ssize_t len;
 495
 496         len = ustcomm_send_unix_sock(sock, lum, sizeof(*lum));
 497         switch (len) {
 498         case sizeof(*lum):
 499                 break;
 500         default:
 501                 if (len < 0) {
 502                         return len;
 503                 } else {
 504                         ERR("incorrect message size: %zd\n", len);
 505                         return -EINVAL;
 506                 }
 507         }
 508         return 0;
 509 }
 510
 511 int ustcomm_recv_app_reply(int sock, struct ustcomm_ust_reply *lur,
 512                           uint32_t expected_handle, uint32_t expected_cmd)
 513 {
 514         ssize_t len;
 515
 516         memset(lur, 0, sizeof(*lur));
 517         len = ustcomm_recv_unix_sock(sock, lur, sizeof(*lur));
 518         switch (len) {
 519         case 0: /* orderly shutdown */
 520                 return -EPIPE;
 521         case sizeof(*lur):
 522         {
 523                 int err = 0;
 524
 525                 if (lur->handle != expected_handle) {
 526                         ERR("Unexpected result message handle: "
 527                                 "expected: %u vs received: %u\n",
 528                                 expected_handle, lur->handle);
 529                         err = 1;
 530                 }
 531                 if (lur->cmd != expected_cmd) {
 532                         ERR("Unexpected result message command "
 533                                 "expected: %u vs received: %u\n",
 534                                 expected_cmd, lur->cmd);
 535                         err = 1;
 536                 }
 537                 if (err) {
 538                         return -EINVAL;
 539                 } else {
 540                         return lur->ret_code;
 541                 }
 542         }
 543         default:
 544                 if (len >= 0) {
 545                         ERR("incorrect message size: %zd\n", len);
 546                 }
 547                 return len;
 548         }
 549 }
 550
 551 int ustcomm_send_app_cmd(int sock,
 552                         struct ustcomm_ust_msg *lum,
 553                         struct ustcomm_ust_reply *lur)
 554 {
 555         int ret;
 556
 557         ret = ustcomm_send_app_msg(sock, lum);
 558         if (ret)
 559                 return ret;
 560         ret = ustcomm_recv_app_reply(sock, lur, lum->handle, lum->cmd);
 561         if (ret > 0)
 562                 return -EIO;
 563         return ret;
 564 }
 565
 566 /*
 567  * chan_data is allocated internally if this function returns the
 568  * expected var_len.
 569  */
 570 ssize_t ustcomm_recv_channel_from_sessiond(int sock,
 571                 void **_chan_data, uint64_t var_len,
 572                 int *_wakeup_fd)
 573 {
 574         void *chan_data;
 575         ssize_t len, nr_fd;
 576         int wakeup_fd, ret;
 577
 578         if (var_len > LTTNG_UST_ABI_CHANNEL_DATA_MAX_LEN) {
 579                 len = -EINVAL;
 580                 goto error_check;
 581         }
 582         /* Receive variable length data */
 583         chan_data = zmalloc(var_len);
 584         if (!chan_data) {
 585                 len = -ENOMEM;
 586                 goto error_alloc;
 587         }
 588         len = ustcomm_recv_unix_sock(sock, chan_data, var_len);
 589         if (len != var_len) {
 590                 goto error_recv;
 591         }
 592         /* recv wakeup fd */
 593         lttng_ust_lock_fd_tracker();
 594         nr_fd = ustcomm_recv_fds_unix_sock(sock, &wakeup_fd, 1);
 595         if (nr_fd <= 0) {
 596                 lttng_ust_unlock_fd_tracker();
 597                 if (nr_fd < 0) {
 598                         len = nr_fd;
 599                         goto error_recv;
 600                 } else {
 601                         len = -EIO;
 602                         goto error_recv;
 603                 }
 604         }
 605
 606         ret = lttng_ust_add_fd_to_tracker(wakeup_fd);
 607         if (ret < 0) {
 608                 ret = close(wakeup_fd);
 609                 if (ret) {
 610                         PERROR("close on wakeup_fd");
 611                 }
 612                 len = -EIO;
 613                 lttng_ust_unlock_fd_tracker();
 614                 goto error_recv;
 615         }
 616
 617         *_wakeup_fd = ret;
 618         lttng_ust_unlock_fd_tracker();
 619
 620         *_chan_data = chan_data;
 621         return len;
 622
 623 error_recv:
 624         free(chan_data);
 625 error_alloc:
 626 error_check:
 627         return len;
 628 }
 629
 630 ssize_t ustcomm_recv_event_notifier_notif_fd_from_sessiond(int sock,
 631                 int *_event_notifier_notif_fd)
 632 {
 633         ssize_t nr_fd;
 634         int event_notifier_notif_fd, ret;
 635
 636         /* Receive event_notifier notification fd */
 637         lttng_ust_lock_fd_tracker();
 638         nr_fd = ustcomm_recv_fds_unix_sock(sock, &event_notifier_notif_fd, 1);
 639         if (nr_fd <= 0) {
 640                 lttng_ust_unlock_fd_tracker();
 641                 if (nr_fd < 0) {
 642                         ret = nr_fd;
 643                         goto error;
 644                 } else {
 645                         ret = -EIO;
 646                         goto error;
 647                 }
 648         }
 649
 650         ret = lttng_ust_add_fd_to_tracker(event_notifier_notif_fd);
 651         if (ret < 0) {
 652                 ret = close(event_notifier_notif_fd);
 653                 if (ret) {
 654                         PERROR("close on event_notifier notif fd");
 655                 }
 656                 ret = -EIO;
 657                 lttng_ust_unlock_fd_tracker();
 658                 goto error;
 659         }
 660
 661         *_event_notifier_notif_fd = ret;
 662         lttng_ust_unlock_fd_tracker();
 663
 664         ret = nr_fd;
 665
 666 error:
 667         return ret;
 668 }
 669
 670 int ustcomm_recv_stream_from_sessiond(int sock,
 671                 uint64_t *memory_map_size __attribute__((unused)),
 672                 int *shm_fd, int *wakeup_fd)
 673 {
 674         ssize_t len;
 675         int ret;
 676         int fds[2];
 677
 678         /* recv shm fd and wakeup fd */
 679         lttng_ust_lock_fd_tracker();
 680         len = ustcomm_recv_fds_unix_sock(sock, fds, 2);
 681         if (len <= 0) {
 682                 lttng_ust_unlock_fd_tracker();
 683                 if (len < 0) {
 684                         ret = len;
 685                         goto error;
 686                 } else {
 687                         ret = -EIO;
 688                         goto error;
 689                 }
 690         }
 691
 692         ret = lttng_ust_add_fd_to_tracker(fds[0]);
 693         if (ret < 0) {
 694                 ret = close(fds[0]);
 695                 if (ret) {
 696                         PERROR("close on received shm_fd");
 697                 }
 698                 ret = -EIO;
 699                 lttng_ust_unlock_fd_tracker();
 700                 goto error;
 701         }
 702         *shm_fd = ret;
 703
 704         ret = lttng_ust_add_fd_to_tracker(fds[1]);
 705         if (ret < 0) {
 706                 ret = close(*shm_fd);
 707                 if (ret) {
 708                         PERROR("close on shm_fd");
 709                 }
 710                 *shm_fd = -1;
 711                 ret = close(fds[1]);
 712                 if (ret) {
 713                         PERROR("close on received wakeup_fd");
 714                 }
 715                 ret = -EIO;
 716                 lttng_ust_unlock_fd_tracker();
 717                 goto error;
 718         }
 719         *wakeup_fd = ret;
 720         lttng_ust_unlock_fd_tracker();
 721         return 0;
 722
 723 error:
 724         return ret;
 725 }
 726
 727 ssize_t ustcomm_recv_counter_from_sessiond(int sock,
 728                 void **_counter_data, uint64_t var_len)
 729 {
 730         void *counter_data;
 731         ssize_t len;
 732
 733         if (var_len > LTTNG_UST_ABI_COUNTER_DATA_MAX_LEN) {
 734                 len = -EINVAL;
 735                 goto error_check;
 736         }
 737         /* Receive variable length data */
 738         counter_data = zmalloc(var_len);
 739         if (!counter_data) {
 740                 len = -ENOMEM;
 741                 goto error_alloc;
 742         }
 743         len = ustcomm_recv_unix_sock(sock, counter_data, var_len);
 744         if (len != var_len) {
 745                 goto error_recv;
 746         }
 747         *_counter_data = counter_data;
 748         return len;
 749
 750 error_recv:
 751         free(counter_data);
 752 error_alloc:
 753 error_check:
 754         return len;
 755 }
 756
 757 int ustcomm_recv_counter_shm_from_sessiond(int sock,
 758                 int *shm_fd)
 759 {
 760         ssize_t len;
 761         int ret;
 762         int fds[1];
 763
 764         /* recv shm fd fd */
 765         lttng_ust_lock_fd_tracker();
 766         len = ustcomm_recv_fds_unix_sock(sock, fds, 1);
 767         if (len <= 0) {
 768                 lttng_ust_unlock_fd_tracker();
 769                 if (len < 0) {
 770                         ret = len;
 771                         goto error;
 772                 } else {
 773                         ret = -EIO;
 774                         goto error;
 775                 }
 776         }
 777
 778         ret = lttng_ust_add_fd_to_tracker(fds[0]);
 779         if (ret < 0) {
 780                 ret = close(fds[0]);
 781                 if (ret) {
 782                         PERROR("close on received shm_fd");
 783                 }
 784                 ret = -EIO;
 785                 lttng_ust_unlock_fd_tracker();
 786                 goto error;
 787         }
 788         *shm_fd = ret;
 789         lttng_ust_unlock_fd_tracker();
 790         return 0;
 791
 792 error:
 793         return ret;
 794 }
 795
 796 /*
 797  * Returns 0 on success, negative error value on error.
 798  */
 799 int ustcomm_send_reg_msg(int sock,
 800                 enum lttng_ust_ctl_socket_type type,
 801                 uint32_t bits_per_long,
 802                 uint32_t uint8_t_alignment,
 803                 uint32_t uint16_t_alignment,
 804                 uint32_t uint32_t_alignment,
 805                 uint32_t uint64_t_alignment,
 806                 uint32_t long_alignment,
 807                 const char *procname)
 808 {
 809         ssize_t len;
 810         struct lttng_ust_ctl_reg_msg reg_msg;
 811
 812         reg_msg.magic = LTTNG_UST_ABI_COMM_MAGIC;
 813         reg_msg.major = LTTNG_UST_ABI_MAJOR_VERSION;
 814         reg_msg.minor = LTTNG_UST_ABI_MINOR_VERSION;
 815         reg_msg.pid = getpid();
 816         reg_msg.ppid = getppid();
 817         reg_msg.uid = getuid();
 818         reg_msg.gid = getgid();
 819         reg_msg.bits_per_long = bits_per_long;
 820         reg_msg.uint8_t_alignment = uint8_t_alignment;
 821         reg_msg.uint16_t_alignment = uint16_t_alignment;
 822         reg_msg.uint32_t_alignment = uint32_t_alignment;
 823         reg_msg.uint64_t_alignment = uint64_t_alignment;
 824         reg_msg.long_alignment = long_alignment;
 825         reg_msg.socket_type = type;
 826         memset(reg_msg.name, 0, sizeof(reg_msg.name));
 827         strncpy(reg_msg.name, procname, sizeof(reg_msg.name) - 1);
 828         memset(reg_msg.padding, 0, sizeof(reg_msg.padding));
 829
 830         len = ustcomm_send_unix_sock(sock, &reg_msg, sizeof(reg_msg));
 831         if (len > 0 && len != sizeof(reg_msg))
 832                 return -EIO;
 833         if (len < 0)
 834                 return len;
 835         return 0;
 836 }
 837
 838 static
 839 ssize_t count_one_type(const struct lttng_ust_type_common *lt)
 840 {
 841         switch (lt->type) {
 842         case lttng_ust_type_integer:
 843         case lttng_ust_type_float:
 844         case lttng_ust_type_string:
 845                 return 1;
 846         case lttng_ust_type_enum:
 847                 return count_one_type(lttng_ust_get_type_enum(lt)->container_type) + 1;
 848         case lttng_ust_type_array:
 849                 return count_one_type(lttng_ust_get_type_array(lt)->elem_type) + 1;
 850         case lttng_ust_type_sequence:
 851                 return count_one_type(lttng_ust_get_type_sequence(lt)->elem_type) + 1;
 852         case lttng_ust_type_struct:
 853                 return count_fields_recursive(lttng_ust_get_type_struct(lt)->nr_fields,
 854                                 lttng_ust_get_type_struct(lt)->fields) + 1;
 855
 856         case lttng_ust_type_dynamic:
 857         {
 858                 const struct lttng_ust_event_field * const *choices;
 859                 size_t nr_choices;
 860                 int ret;
 861
 862                 ret = lttng_ust_dynamic_type_choices(&nr_choices,
 863                         &choices);
 864                 if (ret)
 865                         return ret;
 866                 /*
 867                  * Two fields for enum, one field for variant, and
 868                  * one field per choice.
 869                  */
 870                 return count_fields_recursive(nr_choices, choices) + 3;
 871         }
 872
 873         default:
 874                 return -EINVAL;
 875         }
 876         return 0;
 877 }
 878
 879 static
 880 ssize_t count_fields_recursive(size_t nr_fields,
 881                 const struct lttng_ust_event_field * const *lttng_fields)
 882 {
 883         int i;
 884         ssize_t ret, count = 0;
 885
 886         for (i = 0; i < nr_fields; i++) {
 887                 const struct lttng_ust_event_field *lf;
 888
 889                 lf = lttng_fields[i];
 890                 /* skip 'nowrite' fields */
 891                 if (lf->nowrite)
 892                         continue;
 893                 ret = count_one_type(lf->type);
 894                 if (ret < 0)
 895                         return ret;     /* error */
 896                 count += ret;
 897         }
 898         return count;
 899 }
 900
 901 static
 902 ssize_t count_ctx_fields_recursive(size_t nr_fields,
 903                 struct lttng_ust_ctx_field *lttng_fields)
 904 {
 905         int i;
 906         ssize_t ret, count = 0;
 907
 908         for (i = 0; i < nr_fields; i++) {
 909                 const struct lttng_ust_event_field *lf;
 910
 911                 lf = lttng_fields[i].event_field;
 912                 /* skip 'nowrite' fields */
 913                 if (lf->nowrite)
 914                         continue;
 915                 ret = count_one_type(lf->type);
 916                 if (ret < 0)
 917                         return ret;     /* error */
 918                 count += ret;
 919         }
 920         return count;
 921 }
 922
 923 static
 924 int serialize_string_encoding(int32_t *ue,
 925                 enum lttng_ust_string_encoding le)
 926 {
 927         switch (le) {
 928         case lttng_ust_string_encoding_none:
 929                 *ue = lttng_ust_ctl_encode_none;
 930                 break;
 931         case lttng_ust_string_encoding_UTF8:
 932                 *ue = lttng_ust_ctl_encode_UTF8;
 933                 break;
 934         case lttng_ust_string_encoding_ASCII:
 935                 *ue = lttng_ust_ctl_encode_ASCII;
 936                 break;
 937         default:
 938                 return -EINVAL;
 939         }
 940         return 0;
 941 }
 942
 943 static
 944 int serialize_integer_type(struct lttng_ust_ctl_integer_type *uit,
 945                 const struct lttng_ust_type_integer *lit,
 946                 enum lttng_ust_string_encoding lencoding)
 947 {
 948         int32_t encoding;
 949
 950         uit->size = lit->size;
 951         uit->signedness = lit->signedness;
 952         uit->reverse_byte_order = lit->reverse_byte_order;
 953         uit->base = lit->base;
 954         if (serialize_string_encoding(&encoding, lencoding))
 955                 return -EINVAL;
 956         uit->encoding = encoding;
 957         uit->alignment = lit->alignment;
 958         return 0;
 959 }
 960
 961 static
 962 int serialize_dynamic_type(struct lttng_ust_session *session,
 963                 struct lttng_ust_ctl_field *fields, size_t *iter_output,
 964                 const char *field_name)
 965 {
 966         const struct lttng_ust_event_field * const *choices;
 967         char tag_field_name[LTTNG_UST_ABI_SYM_NAME_LEN];
 968         const struct lttng_ust_type_common *tag_type;
 969         const struct lttng_ust_event_field *tag_field_generic;
 970         struct lttng_ust_event_field tag_field = {
 971                 .name = tag_field_name,
 972                 .nowrite = 0,
 973         };
 974         struct lttng_ust_ctl_field *uf;
 975         size_t nr_choices, i;
 976         int ret;
 977
 978         tag_field_generic = lttng_ust_dynamic_type_tag_field();
 979         tag_type = tag_field_generic->type;
 980
 981         /* Serialize enum field. */
 982         strncpy(tag_field_name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
 983         tag_field_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
 984         strncat(tag_field_name,
 985                 "_tag",
 986                 LTTNG_UST_ABI_SYM_NAME_LEN - strlen(tag_field_name) - 1);
 987         tag_field.type = tag_type;
 988         ret = serialize_one_field(session, fields, iter_output,
 989                 &tag_field, NULL);
 990         if (ret)
 991                 return ret;
 992
 993         /* Serialize variant field. */
 994         uf = &fields[*iter_output];
 995         ret = lttng_ust_dynamic_type_choices(&nr_choices, &choices);
 996         if (ret)
 997                 return ret;
 998
 999         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1000         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1001         uf->type.atype = lttng_ust_ctl_atype_variant;
1002         uf->type.u.variant_nestable.nr_choices = nr_choices;
1003         strncpy(uf->type.u.variant_nestable.tag_name,
1004                 tag_field_name,
1005                 LTTNG_UST_ABI_SYM_NAME_LEN);
1006         uf->type.u.variant_nestable.tag_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1007         uf->type.u.variant_nestable.alignment = 0;
1008         (*iter_output)++;
1009
1010         /* Serialize choice fields after variant. */
1011         for (i = 0; i < nr_choices; i++) {
1012                 ret = serialize_one_field(session, fields,
1013                         iter_output, choices[i], NULL);
1014                 if (ret)
1015                         return ret;
1016         }
1017         return 0;
1018 }
1019
1020 static
1021 int serialize_one_type(struct lttng_ust_session *session,
1022                 struct lttng_ust_ctl_field *fields, size_t *iter_output,
1023                 const char *field_name, const struct lttng_ust_type_common *lt,
1024                 enum lttng_ust_string_encoding parent_encoding,
1025                 const char *prev_field_name)
1026 {
1027         int ret;
1028
1029         /*
1030          * Serializing a type (rather than a field) generates a lttng_ust_ctl_field
1031          * entry with 0-length name.
1032          */
1033
1034         switch (lt->type) {
1035         case lttng_ust_type_integer:
1036         {
1037                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1038                 struct lttng_ust_ctl_type *ut = &uf->type;
1039
1040                 if (field_name) {
1041                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1042                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1043                 } else {
1044                         uf->name[0] = '\0';
1045                 }
1046                 ret = serialize_integer_type(&ut->u.integer, lttng_ust_get_type_integer(lt),
1047                                 parent_encoding);
1048                 if (ret)
1049                         return ret;
1050                 ut->atype = lttng_ust_ctl_atype_integer;
1051                 (*iter_output)++;
1052                 break;
1053         }
1054         case lttng_ust_type_float:
1055         {
1056                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1057                 struct lttng_ust_ctl_type *ut = &uf->type;
1058                 struct lttng_ust_ctl_float_type *uft;
1059                 const struct lttng_ust_type_float *lft;
1060
1061                 if (field_name) {
1062                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1063                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1064                 } else {
1065                         uf->name[0] = '\0';
1066                 }
1067                 uft = &ut->u._float;
1068                 lft = lttng_ust_get_type_float(lt);
1069                 uft->exp_dig = lft->exp_dig;
1070                 uft->mant_dig = lft->mant_dig;
1071                 uft->alignment = lft->alignment;
1072                 uft->reverse_byte_order = lft->reverse_byte_order;
1073                 ut->atype = lttng_ust_ctl_atype_float;
1074                 (*iter_output)++;
1075                 break;
1076         }
1077         case lttng_ust_type_string:
1078         {
1079                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1080                 struct lttng_ust_ctl_type *ut = &uf->type;
1081                 int32_t encoding;
1082
1083                 if (field_name) {
1084                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1085                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1086                 } else {
1087                         uf->name[0] = '\0';
1088                 }
1089                 ret = serialize_string_encoding(&encoding, lttng_ust_get_type_string(lt)->encoding);
1090                 if (ret)
1091                         return ret;
1092                 ut->u.string.encoding = encoding;
1093                 ut->atype = lttng_ust_ctl_atype_string;
1094                 (*iter_output)++;
1095                 break;
1096         }
1097         case lttng_ust_type_array:
1098         {
1099                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1100                 struct lttng_ust_ctl_type *ut = &uf->type;
1101
1102                 if (field_name) {
1103                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1104                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1105                 } else {
1106                         uf->name[0] = '\0';
1107                 }
1108                 ut->atype = lttng_ust_ctl_atype_array_nestable;
1109                 ut->u.array_nestable.length = lttng_ust_get_type_array(lt)->length;
1110                 ut->u.array_nestable.alignment = lttng_ust_get_type_array(lt)->alignment;
1111                 (*iter_output)++;
1112
1113                 ret = serialize_one_type(session, fields, iter_output, NULL,
1114                                 lttng_ust_get_type_array(lt)->elem_type,
1115                                 lttng_ust_get_type_array(lt)->encoding, NULL);
1116                 if (ret)
1117                         return -EINVAL;
1118                 break;
1119         }
1120         case lttng_ust_type_sequence:
1121         {
1122                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1123                 struct lttng_ust_ctl_type *ut = &uf->type;
1124                 const char *length_name = lttng_ust_get_type_sequence(lt)->length_name;
1125
1126                 if (field_name) {
1127                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1128                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1129                 } else {
1130                         uf->name[0] = '\0';
1131                 }
1132                 ut->atype = lttng_ust_ctl_atype_sequence_nestable;
1133                 /*
1134                  * If length_name field is NULL, use the previous field
1135                  * as length.
1136                  */
1137                 if (!length_name)
1138                         length_name = prev_field_name;
1139                 if (!length_name)
1140                         return -EINVAL;
1141                 strncpy(ut->u.sequence_nestable.length_name,
1142                         length_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1143                 ut->u.sequence_nestable.length_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1144                 ut->u.sequence_nestable.alignment = lttng_ust_get_type_sequence(lt)->alignment;
1145                 (*iter_output)++;
1146
1147                 ret = serialize_one_type(session, fields, iter_output, NULL,
1148                                 lttng_ust_get_type_sequence(lt)->elem_type,
1149                                 lttng_ust_get_type_sequence(lt)->encoding, NULL);
1150                 if (ret)
1151                         return -EINVAL;
1152                 break;
1153         }
1154         case lttng_ust_type_dynamic:
1155         {
1156                 ret = serialize_dynamic_type(session, fields, iter_output,
1157                                 field_name);
1158                 if (ret)
1159                         return -EINVAL;
1160                 break;
1161         }
1162         case lttng_ust_type_struct:
1163         {
1164                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1165
1166                 if (field_name) {
1167                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1168                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1169                 } else {
1170                         uf->name[0] = '\0';
1171                 }
1172                 uf->type.atype = lttng_ust_ctl_atype_struct_nestable;
1173                 uf->type.u.struct_nestable.nr_fields = lttng_ust_get_type_struct(lt)->nr_fields;
1174                 uf->type.u.struct_nestable.alignment = lttng_ust_get_type_struct(lt)->alignment;
1175                 (*iter_output)++;
1176
1177                 ret = serialize_fields(session, fields, iter_output,
1178                                 lttng_ust_get_type_struct(lt)->nr_fields,
1179                                 lttng_ust_get_type_struct(lt)->fields);
1180                 if (ret)
1181                         return -EINVAL;
1182                 break;
1183         }
1184         case lttng_ust_type_enum:
1185         {
1186                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1187                 struct lttng_ust_ctl_type *ut = &uf->type;
1188
1189                 if (field_name) {
1190                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1191                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1192                 } else {
1193                         uf->name[0] = '\0';
1194                 }
1195                 strncpy(ut->u.enum_nestable.name, lttng_ust_get_type_enum(lt)->desc->name,
1196                                 LTTNG_UST_ABI_SYM_NAME_LEN);
1197                 ut->u.enum_nestable.name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1198                 ut->atype = lttng_ust_ctl_atype_enum_nestable;
1199                 (*iter_output)++;
1200
1201                 ret = serialize_one_type(session, fields, iter_output, NULL,
1202                                 lttng_ust_get_type_enum(lt)->container_type,
1203                                 lttng_ust_string_encoding_none, NULL);
1204                 if (ret)
1205                         return -EINVAL;
1206                 if (session) {
1207                         const struct lttng_enum *_enum;
1208
1209                         _enum = lttng_ust_enum_get_from_desc(session, lttng_ust_get_type_enum(lt)->desc);
1210                         if (!_enum)
1211                                 return -EINVAL;
1212                         ut->u.enum_nestable.id = _enum->id;
1213                 } else {
1214                         ut->u.enum_nestable.id = -1ULL;
1215                 }
1216                 break;
1217         }
1218         default:
1219                 return -EINVAL;
1220         }
1221         return 0;
1222 }
1223
1224 static
1225 int serialize_one_field(struct lttng_ust_session *session,
1226                 struct lttng_ust_ctl_field *fields, size_t *iter_output,
1227                 const struct lttng_ust_event_field *lf,
1228                 const char **prev_field_name_p)
1229 {
1230         const char *prev_field_name = NULL;
1231         int ret;
1232
1233         /* skip 'nowrite' fields */
1234         if (lf->nowrite)
1235                 return 0;
1236
1237         if (prev_field_name_p)
1238                 prev_field_name = *prev_field_name_p;
1239         ret = serialize_one_type(session, fields, iter_output, lf->name, lf->type,
1240                         lttng_ust_string_encoding_none, prev_field_name);
1241         if (prev_field_name_p)
1242                 *prev_field_name_p = lf->name;
1243         return ret;
1244 }
1245
1246 static
1247 int serialize_fields(struct lttng_ust_session *session,
1248                 struct lttng_ust_ctl_field *lttng_ust_ctl_fields,
1249                 size_t *iter_output, size_t nr_lttng_fields,
1250                 const struct lttng_ust_event_field * const *lttng_fields)
1251 {
1252         const char *prev_field_name = NULL;
1253         int ret;
1254         size_t i;
1255
1256         for (i = 0; i < nr_lttng_fields; i++) {
1257                 ret = serialize_one_field(session, lttng_ust_ctl_fields,
1258                                 iter_output, lttng_fields[i],
1259                                 &prev_field_name);
1260                 if (ret)
1261                         return ret;
1262         }
1263         return 0;
1264 }
1265
1266 static
1267 int alloc_serialize_fields(struct lttng_ust_session *session,
1268                 size_t *_nr_write_fields,
1269                 struct lttng_ust_ctl_field **lttng_ust_ctl_fields,
1270                 size_t nr_fields,
1271                 const struct lttng_ust_event_field * const *lttng_fields)
1272 {
1273         struct lttng_ust_ctl_field *fields;
1274         int ret;
1275         size_t iter_output = 0;
1276         ssize_t nr_write_fields;
1277
1278         nr_write_fields = count_fields_recursive(nr_fields, lttng_fields);
1279         if (nr_write_fields < 0) {
1280                 return (int) nr_write_fields;
1281         }
1282
1283         fields = zmalloc(nr_write_fields * sizeof(*fields));
1284         if (!fields)
1285                 return -ENOMEM;
1286
1287         ret = serialize_fields(session, fields, &iter_output, nr_fields,
1288                         lttng_fields);
1289         if (ret)
1290                 goto error_type;
1291
1292         *_nr_write_fields = nr_write_fields;
1293         *lttng_ust_ctl_fields = fields;
1294         return 0;
1295
1296 error_type:
1297         free(fields);
1298         return ret;
1299 }
1300
1301 static
1302 int serialize_entries(struct lttng_ust_ctl_enum_entry **_entries,
1303                 size_t nr_entries,
1304                 const struct lttng_ust_enum_entry * const *lttng_entries)
1305 {
1306         struct lttng_ust_ctl_enum_entry *entries;
1307         int i;
1308
1309         /* Serialize the entries */
1310         entries = zmalloc(nr_entries * sizeof(*entries));
1311         if (!entries)
1312                 return -ENOMEM;
1313         for (i = 0; i < nr_entries; i++) {
1314                 struct lttng_ust_ctl_enum_entry *uentry;
1315                 const struct lttng_ust_enum_entry *lentry;
1316
1317                 uentry = &entries[i];
1318                 lentry = lttng_entries[i];
1319
1320                 uentry->start.value = lentry->start.value;
1321                 uentry->start.signedness = lentry->start.signedness;
1322                 uentry->end.value = lentry->end.value;
1323                 uentry->end.signedness = lentry->end.signedness;
1324                 strncpy(uentry->string, lentry->string, LTTNG_UST_ABI_SYM_NAME_LEN);
1325                 uentry->string[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1326
1327                 if (lentry->options & LTTNG_UST_ENUM_ENTRY_OPTION_IS_AUTO) {
1328                         uentry->u.extra.options |=
1329                                 LTTNG_UST_CTL_UST_ENUM_ENTRY_OPTION_IS_AUTO;
1330                 }
1331         }
1332         *_entries = entries;
1333         return 0;
1334 }
1335
1336 static
1337 int serialize_ctx_fields(struct lttng_ust_session *session,
1338                 size_t *_nr_write_fields,
1339                 struct lttng_ust_ctl_field **lttng_ust_ctl_fields,
1340                 size_t nr_fields,
1341                 struct lttng_ust_ctx_field *lttng_fields)
1342 {
1343         struct lttng_ust_ctl_field *fields;
1344         const char *prev_field_name = NULL;
1345         size_t i, iter_output = 0;
1346         ssize_t nr_write_fields;
1347         int ret;
1348
1349         nr_write_fields = count_ctx_fields_recursive(nr_fields,
1350                         lttng_fields);
1351         if (nr_write_fields < 0) {
1352                 return (int) nr_write_fields;
1353         }
1354
1355         fields = zmalloc(nr_write_fields * sizeof(*fields));
1356         if (!fields)
1357                 return -ENOMEM;
1358
1359         for (i = 0; i < nr_fields; i++) {
1360                 ret = serialize_one_field(session, fields, &iter_output,
1361                                 lttng_fields[i].event_field, &prev_field_name);
1362                 if (ret)
1363                         goto error_type;
1364         }
1365
1366         *_nr_write_fields = nr_write_fields;
1367         *lttng_ust_ctl_fields = fields;
1368         return 0;
1369
1370 error_type:
1371         free(fields);
1372         return ret;
1373 }
1374
1375 /*
1376  * Returns 0 on success, negative error value on error.
1377  */
1378 int ustcomm_register_event(int sock,
1379         struct lttng_ust_session *session,
1380         int session_objd,               /* session descriptor */
1381         int channel_objd,               /* channel descriptor */
1382         const char *event_name,         /* event name (input) */
1383         int loglevel,
1384         const char *signature,          /* event signature (input) */
1385         size_t nr_fields,               /* fields */
1386         const struct lttng_ust_event_field * const *lttng_fields,
1387         const char *model_emf_uri,
1388         uint32_t *id)                   /* event id (output) */
1389 {
1390         ssize_t len;
1391         struct {
1392                 struct ustcomm_notify_hdr header;
1393                 struct ustcomm_notify_event_msg m;
1394         } msg;
1395         struct {
1396                 struct ustcomm_notify_hdr header;
1397                 struct ustcomm_notify_event_reply r;
1398         } reply;
1399         size_t signature_len, fields_len, model_emf_uri_len;
1400         struct lttng_ust_ctl_field *fields = NULL;
1401         size_t nr_write_fields = 0;
1402         int ret;
1403
1404         memset(&msg, 0, sizeof(msg));
1405         msg.header.notify_cmd = LTTNG_UST_CTL_NOTIFY_CMD_EVENT;
1406         msg.m.session_objd = session_objd;
1407         msg.m.channel_objd = channel_objd;
1408         strncpy(msg.m.event_name, event_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1409         msg.m.event_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1410         msg.m.loglevel = loglevel;
1411         signature_len = strlen(signature) + 1;
1412         msg.m.signature_len = signature_len;
1413
1414         /* Calculate fields len, serialize fields. */
1415         if (nr_fields > 0) {
1416                 ret = alloc_serialize_fields(session, &nr_write_fields, &fields,
1417                                 nr_fields, lttng_fields);
1418                 if (ret)
1419                         return ret;
1420         }
1421
1422         fields_len = sizeof(*fields) * nr_write_fields;
1423         msg.m.fields_len = fields_len;
1424         if (model_emf_uri) {
1425                 model_emf_uri_len = strlen(model_emf_uri) + 1;
1426         } else {
1427                 model_emf_uri_len = 0;
1428         }
1429         msg.m.model_emf_uri_len = model_emf_uri_len;
1430
1431         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1432         if (len > 0 && len != sizeof(msg)) {
1433                 ret = -EIO;
1434                 goto error_fields;
1435         }
1436         if (len < 0) {
1437                 ret = len;
1438                 goto error_fields;
1439         }
1440
1441         /* send signature */
1442         len = ustcomm_send_unix_sock(sock, signature, signature_len);
1443         if (len > 0 && len != signature_len) {
1444                 ret = -EIO;
1445                 goto error_fields;
1446         }
1447         if (len < 0) {
1448                 ret = len;
1449                 goto error_fields;
1450         }
1451
1452         /* send fields */
1453         if (fields_len > 0) {
1454                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
1455                 if (len > 0 && len != fields_len) {
1456                         ret = -EIO;
1457                         goto error_fields;
1458                 }
1459                 if (len < 0) {
1460                         ret = len;
1461                         goto error_fields;
1462                 }
1463         }
1464         free(fields);
1465
1466         if (model_emf_uri_len) {
1467                 /* send model_emf_uri */
1468                 len = ustcomm_send_unix_sock(sock, model_emf_uri,
1469                                 model_emf_uri_len);
1470                 if (len > 0 && len != model_emf_uri_len) {
1471                         return -EIO;
1472                 }
1473                 if (len < 0) {
1474                         return len;
1475                 }
1476         }
1477
1478         /* receive reply */
1479         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1480         switch (len) {
1481         case 0: /* orderly shutdown */
1482                 return -EPIPE;
1483         case sizeof(reply):
1484                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1485                         ERR("Unexpected result message command "
1486                                 "expected: %u vs received: %u\n",
1487                                 msg.header.notify_cmd, reply.header.notify_cmd);
1488                         return -EINVAL;
1489                 }
1490                 if (reply.r.ret_code > 0)
1491                         return -EINVAL;
1492                 if (reply.r.ret_code < 0)
1493                         return reply.r.ret_code;
1494                 *id = reply.r.event_id;
1495                 DBG("Sent register event notification for name \"%s\": ret_code %d, event_id %u\n",
1496                         event_name, reply.r.ret_code, reply.r.event_id);
1497                 return 0;
1498         default:
1499                 if (len < 0) {
1500                         /* Transport level error */
1501                         if (errno == EPIPE || errno == ECONNRESET)
1502                                 len = -errno;
1503                         return len;
1504                 } else {
1505                         ERR("incorrect message size: %zd\n", len);
1506                         return len;
1507                 }
1508         }
1509         /* Unreached. */
1510
1511         /* Error path only. */
1512 error_fields:
1513         free(fields);
1514         return ret;
1515 }
1516
1517 /*
1518  * Returns 0 on success, negative error value on error.
1519  * Returns -EPIPE or -ECONNRESET if other end has hung up.
1520  */
1521 int ustcomm_register_enum(int sock,
1522         int session_objd,               /* session descriptor */
1523         const char *enum_name,          /* enum name (input) */
1524         size_t nr_entries,              /* entries */
1525         const struct lttng_ust_enum_entry * const *lttng_entries,
1526         uint64_t *id)
1527 {
1528         ssize_t len;
1529         struct {
1530                 struct ustcomm_notify_hdr header;
1531                 struct ustcomm_notify_enum_msg m;
1532         } msg;
1533         struct {
1534                 struct ustcomm_notify_hdr header;
1535                 struct ustcomm_notify_enum_reply r;
1536         } reply;
1537         size_t entries_len;
1538         struct lttng_ust_ctl_enum_entry *entries = NULL;
1539         int ret;
1540
1541         memset(&msg, 0, sizeof(msg));
1542         msg.header.notify_cmd = LTTNG_UST_CTL_NOTIFY_CMD_ENUM;
1543         msg.m.session_objd = session_objd;
1544         strncpy(msg.m.enum_name, enum_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1545         msg.m.enum_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1546
1547         /* Calculate entries len, serialize entries. */
1548         if (nr_entries > 0) {
1549                 ret = serialize_entries(&entries,
1550                                 nr_entries, lttng_entries);
1551                 if (ret)
1552                         return ret;
1553         }
1554
1555         entries_len = sizeof(*entries) * nr_entries;
1556         msg.m.entries_len = entries_len;
1557
1558         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1559         if (len > 0 && len != sizeof(msg)) {
1560                 ret = -EIO;
1561                 goto error_entries;
1562         }
1563         if (len < 0) {
1564                 ret = len;
1565                 goto error_entries;
1566         }
1567
1568         /* send entries */
1569         if (entries_len > 0) {
1570                 len = ustcomm_send_unix_sock(sock, entries, entries_len);
1571                 if (len > 0 && len != entries_len) {
1572                         ret = -EIO;
1573                         goto error_entries;
1574                 }
1575                 if (len < 0) {
1576                         ret = len;
1577                         goto error_entries;
1578                 }
1579         }
1580         free(entries);
1581         entries = NULL;
1582
1583         /* receive reply */
1584         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1585         switch (len) {
1586         case 0: /* orderly shutdown */
1587                 return -EPIPE;
1588         case sizeof(reply):
1589                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1590                         ERR("Unexpected result message command "
1591                                 "expected: %u vs received: %u\n",
1592                                 msg.header.notify_cmd, reply.header.notify_cmd);
1593                         return -EINVAL;
1594                 }
1595                 if (reply.r.ret_code > 0)
1596                         return -EINVAL;
1597                 if (reply.r.ret_code < 0)
1598                         return reply.r.ret_code;
1599                 *id = reply.r.enum_id;
1600                 DBG("Sent register enum notification for name \"%s\": ret_code %d\n",
1601                         enum_name, reply.r.ret_code);
1602                 return 0;
1603         default:
1604                 if (len < 0) {
1605                         /* Transport level error */
1606                         if (errno == EPIPE || errno == ECONNRESET)
1607                                 len = -errno;
1608                         return len;
1609                 } else {
1610                         ERR("incorrect message size: %zd\n", len);
1611                         return len;
1612                 }
1613         }
1614         return ret;
1615
1616 error_entries:
1617         free(entries);
1618         return ret;
1619 }
1620
1621 /*
1622  * Returns 0 on success, negative error value on error.
1623  * Returns -EPIPE or -ECONNRESET if other end has hung up.
1624  */
1625 int ustcomm_register_channel(int sock,
1626         struct lttng_ust_session *session,
1627         int session_objd,               /* session descriptor */
1628         int channel_objd,               /* channel descriptor */
1629         size_t nr_ctx_fields,
1630         struct lttng_ust_ctx_field *ctx_fields,
1631         uint32_t *chan_id,              /* channel id (output) */
1632         int *header_type)               /* header type (output) */
1633 {
1634         ssize_t len;
1635         struct {
1636                 struct ustcomm_notify_hdr header;
1637                 struct ustcomm_notify_channel_msg m;
1638         } msg;
1639         struct {
1640                 struct ustcomm_notify_hdr header;
1641                 struct ustcomm_notify_channel_reply r;
1642         } reply;
1643         size_t fields_len;
1644         struct lttng_ust_ctl_field *fields = NULL;
1645         int ret;
1646         size_t nr_write_fields = 0;
1647
1648         memset(&msg, 0, sizeof(msg));
1649         msg.header.notify_cmd = LTTNG_UST_CTL_NOTIFY_CMD_CHANNEL;
1650         msg.m.session_objd = session_objd;
1651         msg.m.channel_objd = channel_objd;
1652
1653         /* Calculate fields len, serialize fields. */
1654         if (nr_ctx_fields > 0) {
1655                 ret = serialize_ctx_fields(session, &nr_write_fields, &fields,
1656                                 nr_ctx_fields, ctx_fields);
1657                 if (ret)
1658                         return ret;
1659         }
1660
1661         fields_len = sizeof(*fields) * nr_write_fields;
1662         msg.m.ctx_fields_len = fields_len;
1663         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1664         if (len > 0 && len != sizeof(msg)) {
1665                 free(fields);
1666                 return -EIO;
1667         }
1668         if (len < 0) {
1669                 free(fields);
1670                 return len;
1671         }
1672
1673         /* send fields */
1674         if (fields_len > 0) {
1675                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
1676                 free(fields);
1677                 if (len > 0 && len != fields_len) {
1678                         return -EIO;
1679                 }
1680                 if (len < 0) {
1681                         return len;
1682                 }
1683         } else {
1684                 free(fields);
1685         }
1686
1687         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1688         switch (len) {
1689         case 0: /* orderly shutdown */
1690                 return -EPIPE;
1691         case sizeof(reply):
1692                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1693                         ERR("Unexpected result message command "
1694                                 "expected: %u vs received: %u\n",
1695                                 msg.header.notify_cmd, reply.header.notify_cmd);
1696                         return -EINVAL;
1697                 }
1698                 if (reply.r.ret_code > 0)
1699                         return -EINVAL;
1700                 if (reply.r.ret_code < 0)
1701                         return reply.r.ret_code;
1702                 *chan_id = reply.r.chan_id;
1703                 switch (reply.r.header_type) {
1704                 case 1:
1705                 case 2:
1706                         *header_type = reply.r.header_type;
1707                         break;
1708                 default:
1709                         ERR("Unexpected channel header type %u\n",
1710                                 reply.r.header_type);
1711                         return -EINVAL;
1712                 }
1713                 DBG("Sent register channel notification: chan_id %d, header_type %d\n",
1714                         reply.r.chan_id, reply.r.header_type);
1715                 return 0;
1716         default:
1717                 if (len < 0) {
1718                         /* Transport level error */
1719                         if (errno == EPIPE || errno == ECONNRESET)
1720                                 len = -errno;
1721                         return len;
1722                 } else {
1723                         ERR("incorrect message size: %zd\n", len);
1724                         return len;
1725                 }
1726         }
1727 }
1728
1729 /*
1730  * Set socket reciving timeout.
1731  */
1732 int ustcomm_setsockopt_rcv_timeout(int sock, unsigned int msec)
1733 {
1734         int ret;
1735         struct timeval tv;
1736
1737         tv.tv_sec = msec / 1000;
1738         tv.tv_usec = (msec * 1000 % 1000000);
1739
1740         ret = setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
1741         if (ret < 0) {
1742                 PERROR("setsockopt SO_RCVTIMEO");
1743                 ret = -errno;
1744         }
1745
1746         return ret;
1747 }
1748
1749 /*
1750  * Set socket sending timeout.
1751  */
1752 int ustcomm_setsockopt_snd_timeout(int sock, unsigned int msec)
1753 {
1754         int ret;
1755         struct timeval tv;
1756
1757         tv.tv_sec = msec / 1000;
1758         tv.tv_usec = (msec * 1000) % 1000000;
1759
1760         ret = setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
1761         if (ret < 0) {
1762                 PERROR("setsockopt SO_SNDTIMEO");
1763                 ret = -errno;
1764         }
1765
1766         return ret;
1767 }