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 {
 808         ssize_t len;
 809         struct lttng_ust_ctl_reg_msg reg_msg;
 810
 811         reg_msg.magic = LTTNG_UST_ABI_COMM_MAGIC;
 812         reg_msg.major = LTTNG_UST_ABI_MAJOR_VERSION;
 813         reg_msg.minor = LTTNG_UST_ABI_MINOR_VERSION;
 814         reg_msg.pid = getpid();
 815         reg_msg.ppid = getppid();
 816         reg_msg.uid = getuid();
 817         reg_msg.gid = getgid();
 818         reg_msg.bits_per_long = bits_per_long;
 819         reg_msg.uint8_t_alignment = uint8_t_alignment;
 820         reg_msg.uint16_t_alignment = uint16_t_alignment;
 821         reg_msg.uint32_t_alignment = uint32_t_alignment;
 822         reg_msg.uint64_t_alignment = uint64_t_alignment;
 823         reg_msg.long_alignment = long_alignment;
 824         reg_msg.socket_type = type;
 825         lttng_pthread_getname_np(reg_msg.name, LTTNG_UST_ABI_PROCNAME_LEN);
 826         memset(reg_msg.padding, 0, sizeof(reg_msg.padding));
 827
 828         len = ustcomm_send_unix_sock(sock, &reg_msg, sizeof(reg_msg));
 829         if (len > 0 && len != sizeof(reg_msg))
 830                 return -EIO;
 831         if (len < 0)
 832                 return len;
 833         return 0;
 834 }
 835
 836 static
 837 ssize_t count_one_type(const struct lttng_ust_type_common *lt)
 838 {
 839         switch (lt->type) {
 840         case lttng_ust_type_integer:
 841         case lttng_ust_type_float:
 842         case lttng_ust_type_string:
 843                 return 1;
 844         case lttng_ust_type_enum:
 845                 return count_one_type(lttng_ust_get_type_enum(lt)->container_type) + 1;
 846         case lttng_ust_type_array:
 847                 return count_one_type(lttng_ust_get_type_array(lt)->elem_type) + 1;
 848         case lttng_ust_type_sequence:
 849                 return count_one_type(lttng_ust_get_type_sequence(lt)->elem_type) + 1;
 850         case lttng_ust_type_struct:
 851                 return count_fields_recursive(lttng_ust_get_type_struct(lt)->nr_fields,
 852                                 lttng_ust_get_type_struct(lt)->fields) + 1;
 853
 854         case lttng_ust_type_dynamic:
 855         {
 856                 const struct lttng_ust_event_field * const *choices;
 857                 size_t nr_choices;
 858                 int ret;
 859
 860                 ret = lttng_ust_dynamic_type_choices(&nr_choices,
 861                         &choices);
 862                 if (ret)
 863                         return ret;
 864                 /*
 865                  * Two fields for enum, one field for variant, and
 866                  * one field per choice.
 867                  */
 868                 return count_fields_recursive(nr_choices, choices) + 3;
 869         }
 870
 871         default:
 872                 return -EINVAL;
 873         }
 874         return 0;
 875 }
 876
 877 static
 878 ssize_t count_fields_recursive(size_t nr_fields,
 879                 const struct lttng_ust_event_field * const *lttng_fields)
 880 {
 881         int i;
 882         ssize_t ret, count = 0;
 883
 884         for (i = 0; i < nr_fields; i++) {
 885                 const struct lttng_ust_event_field *lf;
 886
 887                 lf = lttng_fields[i];
 888                 /* skip 'nowrite' fields */
 889                 if (lf->nowrite)
 890                         continue;
 891                 ret = count_one_type(lf->type);
 892                 if (ret < 0)
 893                         return ret;     /* error */
 894                 count += ret;
 895         }
 896         return count;
 897 }
 898
 899 static
 900 ssize_t count_ctx_fields_recursive(size_t nr_fields,
 901                 struct lttng_ust_ctx_field *lttng_fields)
 902 {
 903         int i;
 904         ssize_t ret, count = 0;
 905
 906         for (i = 0; i < nr_fields; i++) {
 907                 const struct lttng_ust_event_field *lf;
 908
 909                 lf = lttng_fields[i].event_field;
 910                 /* skip 'nowrite' fields */
 911                 if (lf->nowrite)
 912                         continue;
 913                 ret = count_one_type(lf->type);
 914                 if (ret < 0)
 915                         return ret;     /* error */
 916                 count += ret;
 917         }
 918         return count;
 919 }
 920
 921 static
 922 int serialize_string_encoding(int32_t *ue,
 923                 enum lttng_ust_string_encoding le)
 924 {
 925         switch (le) {
 926         case lttng_ust_string_encoding_none:
 927                 *ue = lttng_ust_ctl_encode_none;
 928                 break;
 929         case lttng_ust_string_encoding_UTF8:
 930                 *ue = lttng_ust_ctl_encode_UTF8;
 931                 break;
 932         case lttng_ust_string_encoding_ASCII:
 933                 *ue = lttng_ust_ctl_encode_ASCII;
 934                 break;
 935         default:
 936                 return -EINVAL;
 937         }
 938         return 0;
 939 }
 940
 941 static
 942 int serialize_integer_type(struct lttng_ust_ctl_integer_type *uit,
 943                 const struct lttng_ust_type_integer *lit,
 944                 enum lttng_ust_string_encoding lencoding)
 945 {
 946         int32_t encoding;
 947
 948         uit->size = lit->size;
 949         uit->signedness = lit->signedness;
 950         uit->reverse_byte_order = lit->reverse_byte_order;
 951         uit->base = lit->base;
 952         if (serialize_string_encoding(&encoding, lencoding))
 953                 return -EINVAL;
 954         uit->encoding = encoding;
 955         uit->alignment = lit->alignment;
 956         return 0;
 957 }
 958
 959 static
 960 int serialize_dynamic_type(struct lttng_ust_session *session,
 961                 struct lttng_ust_ctl_field *fields, size_t *iter_output,
 962                 const char *field_name)
 963 {
 964         const struct lttng_ust_event_field * const *choices;
 965         char tag_field_name[LTTNG_UST_ABI_SYM_NAME_LEN];
 966         const struct lttng_ust_type_common *tag_type;
 967         const struct lttng_ust_event_field *tag_field_generic;
 968         struct lttng_ust_event_field tag_field = {
 969                 .name = tag_field_name,
 970                 .nowrite = 0,
 971         };
 972         struct lttng_ust_ctl_field *uf;
 973         size_t nr_choices, i;
 974         int ret;
 975
 976         tag_field_generic = lttng_ust_dynamic_type_tag_field();
 977         tag_type = tag_field_generic->type;
 978
 979         /* Serialize enum field. */
 980         strncpy(tag_field_name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
 981         tag_field_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
 982         strncat(tag_field_name,
 983                 "_tag",
 984                 LTTNG_UST_ABI_SYM_NAME_LEN - strlen(tag_field_name) - 1);
 985         tag_field.type = tag_type;
 986         ret = serialize_one_field(session, fields, iter_output,
 987                 &tag_field, NULL);
 988         if (ret)
 989                 return ret;
 990
 991         /* Serialize variant field. */
 992         uf = &fields[*iter_output];
 993         ret = lttng_ust_dynamic_type_choices(&nr_choices, &choices);
 994         if (ret)
 995                 return ret;
 996
 997         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
 998         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
 999         uf->type.atype = lttng_ust_ctl_atype_variant;
1000         uf->type.u.variant_nestable.nr_choices = nr_choices;
1001         strncpy(uf->type.u.variant_nestable.tag_name,
1002                 tag_field_name,
1003                 LTTNG_UST_ABI_SYM_NAME_LEN);
1004         uf->type.u.variant_nestable.tag_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1005         uf->type.u.variant_nestable.alignment = 0;
1006         (*iter_output)++;
1007
1008         /* Serialize choice fields after variant. */
1009         for (i = 0; i < nr_choices; i++) {
1010                 ret = serialize_one_field(session, fields,
1011                         iter_output, choices[i], NULL);
1012                 if (ret)
1013                         return ret;
1014         }
1015         return 0;
1016 }
1017
1018 static
1019 int serialize_one_type(struct lttng_ust_session *session,
1020                 struct lttng_ust_ctl_field *fields, size_t *iter_output,
1021                 const char *field_name, const struct lttng_ust_type_common *lt,
1022                 enum lttng_ust_string_encoding parent_encoding,
1023                 const char *prev_field_name)
1024 {
1025         int ret;
1026
1027         /*
1028          * Serializing a type (rather than a field) generates a lttng_ust_ctl_field
1029          * entry with 0-length name.
1030          */
1031
1032         switch (lt->type) {
1033         case lttng_ust_type_integer:
1034         {
1035                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1036                 struct lttng_ust_ctl_type *ut = &uf->type;
1037
1038                 if (field_name) {
1039                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1040                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1041                 } else {
1042                         uf->name[0] = '\0';
1043                 }
1044                 ret = serialize_integer_type(&ut->u.integer, lttng_ust_get_type_integer(lt),
1045                                 parent_encoding);
1046                 if (ret)
1047                         return ret;
1048                 ut->atype = lttng_ust_ctl_atype_integer;
1049                 (*iter_output)++;
1050                 break;
1051         }
1052         case lttng_ust_type_float:
1053         {
1054                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1055                 struct lttng_ust_ctl_type *ut = &uf->type;
1056                 struct lttng_ust_ctl_float_type *uft;
1057                 const struct lttng_ust_type_float *lft;
1058
1059                 if (field_name) {
1060                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1061                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1062                 } else {
1063                         uf->name[0] = '\0';
1064                 }
1065                 uft = &ut->u._float;
1066                 lft = lttng_ust_get_type_float(lt);
1067                 uft->exp_dig = lft->exp_dig;
1068                 uft->mant_dig = lft->mant_dig;
1069                 uft->alignment = lft->alignment;
1070                 uft->reverse_byte_order = lft->reverse_byte_order;
1071                 ut->atype = lttng_ust_ctl_atype_float;
1072                 (*iter_output)++;
1073                 break;
1074         }
1075         case lttng_ust_type_string:
1076         {
1077                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1078                 struct lttng_ust_ctl_type *ut = &uf->type;
1079                 int32_t encoding;
1080
1081                 if (field_name) {
1082                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1083                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1084                 } else {
1085                         uf->name[0] = '\0';
1086                 }
1087                 ret = serialize_string_encoding(&encoding, lttng_ust_get_type_string(lt)->encoding);
1088                 if (ret)
1089                         return ret;
1090                 ut->u.string.encoding = encoding;
1091                 ut->atype = lttng_ust_ctl_atype_string;
1092                 (*iter_output)++;
1093                 break;
1094         }
1095         case lttng_ust_type_array:
1096         {
1097                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1098                 struct lttng_ust_ctl_type *ut = &uf->type;
1099
1100                 if (field_name) {
1101                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1102                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1103                 } else {
1104                         uf->name[0] = '\0';
1105                 }
1106                 ut->atype = lttng_ust_ctl_atype_array_nestable;
1107                 ut->u.array_nestable.length = lttng_ust_get_type_array(lt)->length;
1108                 ut->u.array_nestable.alignment = lttng_ust_get_type_array(lt)->alignment;
1109                 (*iter_output)++;
1110
1111                 ret = serialize_one_type(session, fields, iter_output, NULL,
1112                                 lttng_ust_get_type_array(lt)->elem_type,
1113                                 lttng_ust_get_type_array(lt)->encoding, NULL);
1114                 if (ret)
1115                         return -EINVAL;
1116                 break;
1117         }
1118         case lttng_ust_type_sequence:
1119         {
1120                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1121                 struct lttng_ust_ctl_type *ut = &uf->type;
1122                 const char *length_name = lttng_ust_get_type_sequence(lt)->length_name;
1123
1124                 if (field_name) {
1125                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1126                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1127                 } else {
1128                         uf->name[0] = '\0';
1129                 }
1130                 ut->atype = lttng_ust_ctl_atype_sequence_nestable;
1131                 /*
1132                  * If length_name field is NULL, use the previous field
1133                  * as length.
1134                  */
1135                 if (!length_name)
1136                         length_name = prev_field_name;
1137                 if (!length_name)
1138                         return -EINVAL;
1139                 strncpy(ut->u.sequence_nestable.length_name,
1140                         length_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1141                 ut->u.sequence_nestable.length_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1142                 ut->u.sequence_nestable.alignment = lttng_ust_get_type_sequence(lt)->alignment;
1143                 (*iter_output)++;
1144
1145                 ret = serialize_one_type(session, fields, iter_output, NULL,
1146                                 lttng_ust_get_type_sequence(lt)->elem_type,
1147                                 lttng_ust_get_type_sequence(lt)->encoding, NULL);
1148                 if (ret)
1149                         return -EINVAL;
1150                 break;
1151         }
1152         case lttng_ust_type_dynamic:
1153         {
1154                 ret = serialize_dynamic_type(session, fields, iter_output,
1155                                 field_name);
1156                 if (ret)
1157                         return -EINVAL;
1158                 break;
1159         }
1160         case lttng_ust_type_struct:
1161         {
1162                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1163
1164                 if (field_name) {
1165                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1166                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1167                 } else {
1168                         uf->name[0] = '\0';
1169                 }
1170                 uf->type.atype = lttng_ust_ctl_atype_struct_nestable;
1171                 uf->type.u.struct_nestable.nr_fields = lttng_ust_get_type_struct(lt)->nr_fields;
1172                 uf->type.u.struct_nestable.alignment = lttng_ust_get_type_struct(lt)->alignment;
1173                 (*iter_output)++;
1174
1175                 ret = serialize_fields(session, fields, iter_output,
1176                                 lttng_ust_get_type_struct(lt)->nr_fields,
1177                                 lttng_ust_get_type_struct(lt)->fields);
1178                 if (ret)
1179                         return -EINVAL;
1180                 break;
1181         }
1182         case lttng_ust_type_enum:
1183         {
1184                 struct lttng_ust_ctl_field *uf = &fields[*iter_output];
1185                 struct lttng_ust_ctl_type *ut = &uf->type;
1186
1187                 if (field_name) {
1188                         strncpy(uf->name, field_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1189                         uf->name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1190                 } else {
1191                         uf->name[0] = '\0';
1192                 }
1193                 strncpy(ut->u.enum_nestable.name, lttng_ust_get_type_enum(lt)->desc->name,
1194                                 LTTNG_UST_ABI_SYM_NAME_LEN);
1195                 ut->u.enum_nestable.name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1196                 ut->atype = lttng_ust_ctl_atype_enum_nestable;
1197                 (*iter_output)++;
1198
1199                 ret = serialize_one_type(session, fields, iter_output, NULL,
1200                                 lttng_ust_get_type_enum(lt)->container_type,
1201                                 lttng_ust_string_encoding_none, NULL);
1202                 if (ret)
1203                         return -EINVAL;
1204                 if (session) {
1205                         const struct lttng_enum *_enum;
1206
1207                         _enum = lttng_ust_enum_get_from_desc(session, lttng_ust_get_type_enum(lt)->desc);
1208                         if (!_enum)
1209                                 return -EINVAL;
1210                         ut->u.enum_nestable.id = _enum->id;
1211                 } else {
1212                         ut->u.enum_nestable.id = -1ULL;
1213                 }
1214                 break;
1215         }
1216         default:
1217                 return -EINVAL;
1218         }
1219         return 0;
1220 }
1221
1222 static
1223 int serialize_one_field(struct lttng_ust_session *session,
1224                 struct lttng_ust_ctl_field *fields, size_t *iter_output,
1225                 const struct lttng_ust_event_field *lf,
1226                 const char **prev_field_name_p)
1227 {
1228         const char *prev_field_name = NULL;
1229         int ret;
1230
1231         /* skip 'nowrite' fields */
1232         if (lf->nowrite)
1233                 return 0;
1234
1235         if (prev_field_name_p)
1236                 prev_field_name = *prev_field_name_p;
1237         ret = serialize_one_type(session, fields, iter_output, lf->name, lf->type,
1238                         lttng_ust_string_encoding_none, prev_field_name);
1239         if (prev_field_name_p)
1240                 *prev_field_name_p = lf->name;
1241         return ret;
1242 }
1243
1244 static
1245 int serialize_fields(struct lttng_ust_session *session,
1246                 struct lttng_ust_ctl_field *lttng_ust_ctl_fields,
1247                 size_t *iter_output, size_t nr_lttng_fields,
1248                 const struct lttng_ust_event_field * const *lttng_fields)
1249 {
1250         const char *prev_field_name = NULL;
1251         int ret;
1252         size_t i;
1253
1254         for (i = 0; i < nr_lttng_fields; i++) {
1255                 ret = serialize_one_field(session, lttng_ust_ctl_fields,
1256                                 iter_output, lttng_fields[i],
1257                                 &prev_field_name);
1258                 if (ret)
1259                         return ret;
1260         }
1261         return 0;
1262 }
1263
1264 static
1265 int alloc_serialize_fields(struct lttng_ust_session *session,
1266                 size_t *_nr_write_fields,
1267                 struct lttng_ust_ctl_field **lttng_ust_ctl_fields,
1268                 size_t nr_fields,
1269                 const struct lttng_ust_event_field * const *lttng_fields)
1270 {
1271         struct lttng_ust_ctl_field *fields;
1272         int ret;
1273         size_t iter_output = 0;
1274         ssize_t nr_write_fields;
1275
1276         nr_write_fields = count_fields_recursive(nr_fields, lttng_fields);
1277         if (nr_write_fields < 0) {
1278                 return (int) nr_write_fields;
1279         }
1280
1281         fields = zmalloc(nr_write_fields * sizeof(*fields));
1282         if (!fields)
1283                 return -ENOMEM;
1284
1285         ret = serialize_fields(session, fields, &iter_output, nr_fields,
1286                         lttng_fields);
1287         if (ret)
1288                 goto error_type;
1289
1290         *_nr_write_fields = nr_write_fields;
1291         *lttng_ust_ctl_fields = fields;
1292         return 0;
1293
1294 error_type:
1295         free(fields);
1296         return ret;
1297 }
1298
1299 static
1300 int serialize_entries(struct lttng_ust_ctl_enum_entry **_entries,
1301                 size_t nr_entries,
1302                 const struct lttng_ust_enum_entry * const *lttng_entries)
1303 {
1304         struct lttng_ust_ctl_enum_entry *entries;
1305         int i;
1306
1307         /* Serialize the entries */
1308         entries = zmalloc(nr_entries * sizeof(*entries));
1309         if (!entries)
1310                 return -ENOMEM;
1311         for (i = 0; i < nr_entries; i++) {
1312                 struct lttng_ust_ctl_enum_entry *uentry;
1313                 const struct lttng_ust_enum_entry *lentry;
1314
1315                 uentry = &entries[i];
1316                 lentry = lttng_entries[i];
1317
1318                 uentry->start.value = lentry->start.value;
1319                 uentry->start.signedness = lentry->start.signedness;
1320                 uentry->end.value = lentry->end.value;
1321                 uentry->end.signedness = lentry->end.signedness;
1322                 strncpy(uentry->string, lentry->string, LTTNG_UST_ABI_SYM_NAME_LEN);
1323                 uentry->string[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1324
1325                 if (lentry->options & LTTNG_UST_ENUM_ENTRY_OPTION_IS_AUTO) {
1326                         uentry->u.extra.options |=
1327                                 LTTNG_UST_CTL_UST_ENUM_ENTRY_OPTION_IS_AUTO;
1328                 }
1329         }
1330         *_entries = entries;
1331         return 0;
1332 }
1333
1334 static
1335 int serialize_ctx_fields(struct lttng_ust_session *session,
1336                 size_t *_nr_write_fields,
1337                 struct lttng_ust_ctl_field **lttng_ust_ctl_fields,
1338                 size_t nr_fields,
1339                 struct lttng_ust_ctx_field *lttng_fields)
1340 {
1341         struct lttng_ust_ctl_field *fields;
1342         const char *prev_field_name = NULL;
1343         size_t i, iter_output = 0;
1344         ssize_t nr_write_fields;
1345         int ret;
1346
1347         nr_write_fields = count_ctx_fields_recursive(nr_fields,
1348                         lttng_fields);
1349         if (nr_write_fields < 0) {
1350                 return (int) nr_write_fields;
1351         }
1352
1353         fields = zmalloc(nr_write_fields * sizeof(*fields));
1354         if (!fields)
1355                 return -ENOMEM;
1356
1357         for (i = 0; i < nr_fields; i++) {
1358                 ret = serialize_one_field(session, fields, &iter_output,
1359                                 lttng_fields[i].event_field, &prev_field_name);
1360                 if (ret)
1361                         goto error_type;
1362         }
1363
1364         *_nr_write_fields = nr_write_fields;
1365         *lttng_ust_ctl_fields = fields;
1366         return 0;
1367
1368 error_type:
1369         free(fields);
1370         return ret;
1371 }
1372
1373 /*
1374  * Returns 0 on success, negative error value on error.
1375  */
1376 int ustcomm_register_event(int sock,
1377         struct lttng_ust_session *session,
1378         int session_objd,               /* session descriptor */
1379         int channel_objd,               /* channel descriptor */
1380         const char *event_name,         /* event name (input) */
1381         int loglevel,
1382         const char *signature,          /* event signature (input) */
1383         size_t nr_fields,               /* fields */
1384         const struct lttng_ust_event_field * const *lttng_fields,
1385         const char *model_emf_uri,
1386         uint32_t *id)                   /* event id (output) */
1387 {
1388         ssize_t len;
1389         struct {
1390                 struct ustcomm_notify_hdr header;
1391                 struct ustcomm_notify_event_msg m;
1392         } msg;
1393         struct {
1394                 struct ustcomm_notify_hdr header;
1395                 struct ustcomm_notify_event_reply r;
1396         } reply;
1397         size_t signature_len, fields_len, model_emf_uri_len;
1398         struct lttng_ust_ctl_field *fields = NULL;
1399         size_t nr_write_fields = 0;
1400         int ret;
1401
1402         memset(&msg, 0, sizeof(msg));
1403         msg.header.notify_cmd = LTTNG_UST_CTL_NOTIFY_CMD_EVENT;
1404         msg.m.session_objd = session_objd;
1405         msg.m.channel_objd = channel_objd;
1406         strncpy(msg.m.event_name, event_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1407         msg.m.event_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1408         msg.m.loglevel = loglevel;
1409         signature_len = strlen(signature) + 1;
1410         msg.m.signature_len = signature_len;
1411
1412         /* Calculate fields len, serialize fields. */
1413         if (nr_fields > 0) {
1414                 ret = alloc_serialize_fields(session, &nr_write_fields, &fields,
1415                                 nr_fields, lttng_fields);
1416                 if (ret)
1417                         return ret;
1418         }
1419
1420         fields_len = sizeof(*fields) * nr_write_fields;
1421         msg.m.fields_len = fields_len;
1422         if (model_emf_uri) {
1423                 model_emf_uri_len = strlen(model_emf_uri) + 1;
1424         } else {
1425                 model_emf_uri_len = 0;
1426         }
1427         msg.m.model_emf_uri_len = model_emf_uri_len;
1428
1429         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1430         if (len > 0 && len != sizeof(msg)) {
1431                 ret = -EIO;
1432                 goto error_fields;
1433         }
1434         if (len < 0) {
1435                 ret = len;
1436                 goto error_fields;
1437         }
1438
1439         /* send signature */
1440         len = ustcomm_send_unix_sock(sock, signature, signature_len);
1441         if (len > 0 && len != signature_len) {
1442                 ret = -EIO;
1443                 goto error_fields;
1444         }
1445         if (len < 0) {
1446                 ret = len;
1447                 goto error_fields;
1448         }
1449
1450         /* send fields */
1451         if (fields_len > 0) {
1452                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
1453                 if (len > 0 && len != fields_len) {
1454                         ret = -EIO;
1455                         goto error_fields;
1456                 }
1457                 if (len < 0) {
1458                         ret = len;
1459                         goto error_fields;
1460                 }
1461         }
1462         free(fields);
1463
1464         if (model_emf_uri_len) {
1465                 /* send model_emf_uri */
1466                 len = ustcomm_send_unix_sock(sock, model_emf_uri,
1467                                 model_emf_uri_len);
1468                 if (len > 0 && len != model_emf_uri_len) {
1469                         return -EIO;
1470                 }
1471                 if (len < 0) {
1472                         return len;
1473                 }
1474         }
1475
1476         /* receive reply */
1477         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1478         switch (len) {
1479         case 0: /* orderly shutdown */
1480                 return -EPIPE;
1481         case sizeof(reply):
1482                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1483                         ERR("Unexpected result message command "
1484                                 "expected: %u vs received: %u\n",
1485                                 msg.header.notify_cmd, reply.header.notify_cmd);
1486                         return -EINVAL;
1487                 }
1488                 if (reply.r.ret_code > 0)
1489                         return -EINVAL;
1490                 if (reply.r.ret_code < 0)
1491                         return reply.r.ret_code;
1492                 *id = reply.r.event_id;
1493                 DBG("Sent register event notification for name \"%s\": ret_code %d, event_id %u\n",
1494                         event_name, reply.r.ret_code, reply.r.event_id);
1495                 return 0;
1496         default:
1497                 if (len < 0) {
1498                         /* Transport level error */
1499                         if (errno == EPIPE || errno == ECONNRESET)
1500                                 len = -errno;
1501                         return len;
1502                 } else {
1503                         ERR("incorrect message size: %zd\n", len);
1504                         return len;
1505                 }
1506         }
1507         /* Unreached. */
1508
1509         /* Error path only. */
1510 error_fields:
1511         free(fields);
1512         return ret;
1513 }
1514
1515 /*
1516  * Returns 0 on success, negative error value on error.
1517  * Returns -EPIPE or -ECONNRESET if other end has hung up.
1518  */
1519 int ustcomm_register_enum(int sock,
1520         int session_objd,               /* session descriptor */
1521         const char *enum_name,          /* enum name (input) */
1522         size_t nr_entries,              /* entries */
1523         const struct lttng_ust_enum_entry * const *lttng_entries,
1524         uint64_t *id)
1525 {
1526         ssize_t len;
1527         struct {
1528                 struct ustcomm_notify_hdr header;
1529                 struct ustcomm_notify_enum_msg m;
1530         } msg;
1531         struct {
1532                 struct ustcomm_notify_hdr header;
1533                 struct ustcomm_notify_enum_reply r;
1534         } reply;
1535         size_t entries_len;
1536         struct lttng_ust_ctl_enum_entry *entries = NULL;
1537         int ret;
1538
1539         memset(&msg, 0, sizeof(msg));
1540         msg.header.notify_cmd = LTTNG_UST_CTL_NOTIFY_CMD_ENUM;
1541         msg.m.session_objd = session_objd;
1542         strncpy(msg.m.enum_name, enum_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1543         msg.m.enum_name[LTTNG_UST_ABI_SYM_NAME_LEN - 1] = '\0';
1544
1545         /* Calculate entries len, serialize entries. */
1546         if (nr_entries > 0) {
1547                 ret = serialize_entries(&entries,
1548                                 nr_entries, lttng_entries);
1549                 if (ret)
1550                         return ret;
1551         }
1552
1553         entries_len = sizeof(*entries) * nr_entries;
1554         msg.m.entries_len = entries_len;
1555
1556         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1557         if (len > 0 && len != sizeof(msg)) {
1558                 ret = -EIO;
1559                 goto error_entries;
1560         }
1561         if (len < 0) {
1562                 ret = len;
1563                 goto error_entries;
1564         }
1565
1566         /* send entries */
1567         if (entries_len > 0) {
1568                 len = ustcomm_send_unix_sock(sock, entries, entries_len);
1569                 if (len > 0 && len != entries_len) {
1570                         ret = -EIO;
1571                         goto error_entries;
1572                 }
1573                 if (len < 0) {
1574                         ret = len;
1575                         goto error_entries;
1576                 }
1577         }
1578         free(entries);
1579         entries = NULL;
1580
1581         /* receive reply */
1582         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1583         switch (len) {
1584         case 0: /* orderly shutdown */
1585                 return -EPIPE;
1586         case sizeof(reply):
1587                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1588                         ERR("Unexpected result message command "
1589                                 "expected: %u vs received: %u\n",
1590                                 msg.header.notify_cmd, reply.header.notify_cmd);
1591                         return -EINVAL;
1592                 }
1593                 if (reply.r.ret_code > 0)
1594                         return -EINVAL;
1595                 if (reply.r.ret_code < 0)
1596                         return reply.r.ret_code;
1597                 *id = reply.r.enum_id;
1598                 DBG("Sent register enum notification for name \"%s\": ret_code %d\n",
1599                         enum_name, reply.r.ret_code);
1600                 return 0;
1601         default:
1602                 if (len < 0) {
1603                         /* Transport level error */
1604                         if (errno == EPIPE || errno == ECONNRESET)
1605                                 len = -errno;
1606                         return len;
1607                 } else {
1608                         ERR("incorrect message size: %zd\n", len);
1609                         return len;
1610                 }
1611         }
1612         return ret;
1613
1614 error_entries:
1615         free(entries);
1616         return ret;
1617 }
1618
1619 /*
1620  * Returns 0 on success, negative error value on error.
1621  * Returns -EPIPE or -ECONNRESET if other end has hung up.
1622  */
1623 int ustcomm_register_channel(int sock,
1624         struct lttng_ust_session *session,
1625         int session_objd,               /* session descriptor */
1626         int channel_objd,               /* channel descriptor */
1627         size_t nr_ctx_fields,
1628         struct lttng_ust_ctx_field *ctx_fields,
1629         uint32_t *chan_id,              /* channel id (output) */
1630         int *header_type)               /* header type (output) */
1631 {
1632         ssize_t len;
1633         struct {
1634                 struct ustcomm_notify_hdr header;
1635                 struct ustcomm_notify_channel_msg m;
1636         } msg;
1637         struct {
1638                 struct ustcomm_notify_hdr header;
1639                 struct ustcomm_notify_channel_reply r;
1640         } reply;
1641         size_t fields_len;
1642         struct lttng_ust_ctl_field *fields = NULL;
1643         int ret;
1644         size_t nr_write_fields = 0;
1645
1646         memset(&msg, 0, sizeof(msg));
1647         msg.header.notify_cmd = LTTNG_UST_CTL_NOTIFY_CMD_CHANNEL;
1648         msg.m.session_objd = session_objd;
1649         msg.m.channel_objd = channel_objd;
1650
1651         /* Calculate fields len, serialize fields. */
1652         if (nr_ctx_fields > 0) {
1653                 ret = serialize_ctx_fields(session, &nr_write_fields, &fields,
1654                                 nr_ctx_fields, ctx_fields);
1655                 if (ret)
1656                         return ret;
1657         }
1658
1659         fields_len = sizeof(*fields) * nr_write_fields;
1660         msg.m.ctx_fields_len = fields_len;
1661         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1662         if (len > 0 && len != sizeof(msg)) {
1663                 free(fields);
1664                 return -EIO;
1665         }
1666         if (len < 0) {
1667                 free(fields);
1668                 return len;
1669         }
1670
1671         /* send fields */
1672         if (fields_len > 0) {
1673                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
1674                 free(fields);
1675                 if (len > 0 && len != fields_len) {
1676                         return -EIO;
1677                 }
1678                 if (len < 0) {
1679                         return len;
1680                 }
1681         } else {
1682                 free(fields);
1683         }
1684
1685         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1686         switch (len) {
1687         case 0: /* orderly shutdown */
1688                 return -EPIPE;
1689         case sizeof(reply):
1690                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1691                         ERR("Unexpected result message command "
1692                                 "expected: %u vs received: %u\n",
1693                                 msg.header.notify_cmd, reply.header.notify_cmd);
1694                         return -EINVAL;
1695                 }
1696                 if (reply.r.ret_code > 0)
1697                         return -EINVAL;
1698                 if (reply.r.ret_code < 0)
1699                         return reply.r.ret_code;
1700                 *chan_id = reply.r.chan_id;
1701                 switch (reply.r.header_type) {
1702                 case 1:
1703                 case 2:
1704                         *header_type = reply.r.header_type;
1705                         break;
1706                 default:
1707                         ERR("Unexpected channel header type %u\n",
1708                                 reply.r.header_type);
1709                         return -EINVAL;
1710                 }
1711                 DBG("Sent register channel notification: chan_id %d, header_type %d\n",
1712                         reply.r.chan_id, reply.r.header_type);
1713                 return 0;
1714         default:
1715                 if (len < 0) {
1716                         /* Transport level error */
1717                         if (errno == EPIPE || errno == ECONNRESET)
1718                                 len = -errno;
1719                         return len;
1720                 } else {
1721                         ERR("incorrect message size: %zd\n", len);
1722                         return len;
1723                 }
1724         }
1725 }
1726
1727 /*
1728  * Set socket reciving timeout.
1729  */
1730 int ustcomm_setsockopt_rcv_timeout(int sock, unsigned int msec)
1731 {
1732         int ret;
1733         struct timeval tv;
1734
1735         tv.tv_sec = msec / 1000;
1736         tv.tv_usec = (msec * 1000 % 1000000);
1737
1738         ret = setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
1739         if (ret < 0) {
1740                 PERROR("setsockopt SO_RCVTIMEO");
1741                 ret = -errno;
1742         }
1743
1744         return ret;
1745 }
1746
1747 /*
1748  * Set socket sending timeout.
1749  */
1750 int ustcomm_setsockopt_snd_timeout(int sock, unsigned int msec)
1751 {
1752         int ret;
1753         struct timeval tv;
1754
1755         tv.tv_sec = msec / 1000;
1756         tv.tv_usec = (msec * 1000) % 1000000;
1757
1758         ret = setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
1759         if (ret < 0) {
1760                 PERROR("setsockopt SO_SNDTIMEO");
1761                 ret = -errno;
1762         }
1763
1764         return ret;
1765 }