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

   1 /*
   2  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C)  2011-2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; only
   8  * version 2.1 of the License.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #define _GNU_SOURCE
  21 #include <limits.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/socket.h>
  26 #include <sys/stat.h>
  27 #include <sys/types.h>
  28 #include <sys/un.h>
  29 #include <unistd.h>
  30 #include <assert.h>
  31 #include <errno.h>
  32 #include <fcntl.h>
  33
  34 #include <lttng/ust-ctl.h>
  35 #include <ust-comm.h>
  36 #include <helper.h>
  37 #include <lttng/ust-error.h>
  38 #include <lttng/ust-events.h>
  39 #include <usterr-signal-safe.h>
  40
  41 #include "../liblttng-ust/compat.h"
  42
  43 #define USTCOMM_CODE_OFFSET(code)       \
  44         (code == LTTNG_UST_OK ? 0 : (code - LTTNG_UST_ERR + 1))
  45
  46 #define USTCOMM_MAX_SEND_FDS    4
  47
  48 /*
  49  * Human readable error message.
  50  */
  51 static const char *ustcomm_readable_code[] = {
  52         [ USTCOMM_CODE_OFFSET(LTTNG_UST_OK) ] = "Success",
  53         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR) ] = "Unknown error",
  54         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_NOENT) ] = "No entry",
  55         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_EXIST) ] = "Object already exists",
  56         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL) ] = "Invalid argument",
  57         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_PERM) ] = "Permission denied",
  58         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_NOSYS) ] = "Not implemented",
  59         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_EXITING) ] = "Process is exiting",
  60
  61         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL_MAGIC) ] = "Invalid magic number",
  62         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_INVAL_SOCKET_TYPE) ] = "Invalid socket type",
  63         [ USTCOMM_CODE_OFFSET(LTTNG_UST_ERR_UNSUP_MAJOR) ] = "Unsupported major version",
  64 };
  65
  66 /*
  67  * lttng_ust_strerror
  68  *
  69  * Receives positive error value.
  70  * Return ptr to string representing a human readable
  71  * error code from the ustcomm_return_code enum.
  72  */
  73 const char *lttng_ust_strerror(int code)
  74 {
  75         if (code == LTTNG_UST_OK)
  76                 return ustcomm_readable_code[USTCOMM_CODE_OFFSET(code)];
  77         if (code < LTTNG_UST_ERR)
  78                 return strerror(code);
  79         if (code >= LTTNG_UST_ERR_NR)
  80                 code = LTTNG_UST_ERR;
  81         return ustcomm_readable_code[USTCOMM_CODE_OFFSET(code)];
  82 }
  83
  84 /*
  85  * ustcomm_connect_unix_sock
  86  *
  87  * Connect to unix socket using the path name.
  88  */
  89 int ustcomm_connect_unix_sock(const char *pathname)
  90 {
  91         struct sockaddr_un sun;
  92         int fd, ret;
  93
  94         /*
  95          * libust threads require the close-on-exec flag for all
  96          * resources so it does not leak file descriptors upon exec.
  97          */
  98         fd = socket(PF_UNIX, SOCK_STREAM, 0);
  99         if (fd < 0) {
 100                 PERROR("socket");
 101                 ret = -errno;
 102                 goto error;
 103         }
 104         ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
 105         if (ret < 0) {
 106                 PERROR("fcntl");
 107                 ret = -errno;
 108                 goto error_fcntl;
 109         }
 110
 111         memset(&sun, 0, sizeof(sun));
 112         sun.sun_family = AF_UNIX;
 113         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 114         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 115
 116         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 117         if (ret < 0) {
 118                 /*
 119                  * Don't print message on connect ENOENT error, because
 120                  * connect is used in normal execution to detect if
 121                  * sessiond is alive. ENOENT is when the unix socket
 122                  * file does not exist, and ECONNREFUSED is when the
 123                  * file exists but no sessiond is listening.
 124                  */
 125                 if (errno != ECONNREFUSED && errno != ECONNRESET
 126                                 && errno != ENOENT && errno != EACCES)
 127                         PERROR("connect");
 128                 ret = -errno;
 129                 if (ret == -ECONNREFUSED || ret == -ECONNRESET)
 130                         ret = -EPIPE;
 131                 goto error_connect;
 132         }
 133
 134         return fd;
 135
 136 error_connect:
 137 error_fcntl:
 138         {
 139                 int closeret;
 140
 141                 closeret = close(fd);
 142                 if (closeret)
 143                         PERROR("close");
 144         }
 145 error:
 146         return ret;
 147 }
 148
 149 /*
 150  * ustcomm_accept_unix_sock
 151  *
 152  * Do an accept(2) on the sock and return the
 153  * new file descriptor. The socket MUST be bind(2) before.
 154  */
 155 int ustcomm_accept_unix_sock(int sock)
 156 {
 157         int new_fd;
 158         struct sockaddr_un sun;
 159         socklen_t len = 0;
 160
 161         /* Blocking call */
 162         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 163         if (new_fd < 0) {
 164                 if (errno != ECONNABORTED)
 165                         PERROR("accept");
 166                 new_fd = -errno;
 167                 if (new_fd == -ECONNABORTED)
 168                         new_fd = -EPIPE;
 169         }
 170         return new_fd;
 171 }
 172
 173 /*
 174  * ustcomm_create_unix_sock
 175  *
 176  * Creates a AF_UNIX local socket using pathname
 177  * bind the socket upon creation and return the fd.
 178  */
 179 int ustcomm_create_unix_sock(const char *pathname)
 180 {
 181         struct sockaddr_un sun;
 182         int fd, ret;
 183
 184         /* Create server socket */
 185         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 186                 PERROR("socket");
 187                 ret = -errno;
 188                 goto error;
 189         }
 190
 191         memset(&sun, 0, sizeof(sun));
 192         sun.sun_family = AF_UNIX;
 193         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 194         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 195
 196         /* Unlink the old file if present */
 197         (void) unlink(pathname);
 198         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 199         if (ret < 0) {
 200                 PERROR("bind");
 201                 ret = -errno;
 202                 goto error_close;
 203         }
 204
 205         return fd;
 206
 207 error_close:
 208         {
 209                 int closeret;
 210
 211                 closeret = close(fd);
 212                 if (closeret) {
 213                         PERROR("close");
 214                 }
 215         }
 216 error:
 217         return ret;
 218 }
 219
 220 /*
 221  * ustcomm_listen_unix_sock
 222  *
 223  * Make the socket listen using LTTNG_UST_COMM_MAX_LISTEN.
 224  */
 225 int ustcomm_listen_unix_sock(int sock)
 226 {
 227         int ret;
 228
 229         ret = listen(sock, LTTNG_UST_COMM_MAX_LISTEN);
 230         if (ret < 0) {
 231                 ret = -errno;
 232                 PERROR("listen");
 233         }
 234
 235         return ret;
 236 }
 237
 238 /*
 239  * ustcomm_close_unix_sock
 240  *
 241  * Shutdown cleanly a unix socket.
 242  */
 243 int ustcomm_close_unix_sock(int sock)
 244 {
 245         int ret;
 246
 247         ret = close(sock);
 248         if (ret < 0) {
 249                 PERROR("close");
 250                 ret = -errno;
 251         }
 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                 int shutret;
 290
 291                 if (errno != EPIPE && errno != ECONNRESET && errno != ECONNREFUSED)
 292                         PERROR("recvmsg");
 293                 ret = -errno;
 294                 if (ret == -ECONNRESET || ret == -ECONNREFUSED)
 295                         ret = -EPIPE;
 296
 297                 shutret = shutdown(sock, SHUT_RDWR);
 298                 if (shutret)
 299                         ERR("Socket shutdown error");
 300         } else if (ret > 0) {
 301                 ret = len;
 302         }
 303         /* ret = 0 means an orderly shutdown. */
 304
 305         return ret;
 306 }
 307
 308 /*
 309  * ustcomm_send_unix_sock
 310  *
 311  * Send buf data of size len. Using sendmsg API.
 312  * Return the size of sent data.
 313  */
 314 ssize_t ustcomm_send_unix_sock(int sock, const void *buf, size_t len)
 315 {
 316         struct msghdr msg;
 317         struct iovec iov[1];
 318         ssize_t ret;
 319
 320         memset(&msg, 0, sizeof(msg));
 321
 322         iov[0].iov_base = (void *) buf;
 323         iov[0].iov_len = len;
 324         msg.msg_iov = iov;
 325         msg.msg_iovlen = 1;
 326
 327         /*
 328          * Using the MSG_NOSIGNAL when sending data from sessiond to
 329          * libust, so libust does not receive an unhandled SIGPIPE or
 330          * SIGURG. The sessiond receiver side can be made more resilient
 331          * by ignoring SIGPIPE, but we don't have this luxury on the
 332          * libust side.
 333          */
 334         do {
 335                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 336         } while (ret < 0 && errno == EINTR);
 337
 338         if (ret < 0) {
 339                 int shutret;
 340
 341                 if (errno != EPIPE && errno != ECONNRESET)
 342                         PERROR("sendmsg");
 343                 ret = -errno;
 344                 if (ret == -ECONNRESET)
 345                         ret = -EPIPE;
 346
 347                 shutret = shutdown(sock, SHUT_RDWR);
 348                 if (shutret)
 349                         ERR("Socket shutdown error");
 350         }
 351
 352         return ret;
 353 }
 354
 355 /*
 356  * Send a message accompanied by fd(s) over a unix socket.
 357  *
 358  * Returns the size of data sent, or negative error value.
 359  */
 360 ssize_t ustcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 361 {
 362         struct msghdr msg;
 363         struct cmsghdr *cmptr;
 364         struct iovec iov[1];
 365         ssize_t ret = -1;
 366         unsigned int sizeof_fds = nb_fd * sizeof(int);
 367         char tmp[CMSG_SPACE(sizeof_fds)];
 368         char dummy = 0;
 369
 370         memset(&msg, 0, sizeof(msg));
 371         memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
 372
 373         if (nb_fd > USTCOMM_MAX_SEND_FDS)
 374                 return -EINVAL;
 375
 376         msg.msg_control = (caddr_t)tmp;
 377         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 378
 379         cmptr = CMSG_FIRSTHDR(&msg);
 380         cmptr->cmsg_level = SOL_SOCKET;
 381         cmptr->cmsg_type = SCM_RIGHTS;
 382         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 383         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 384         /* Sum of the length of all control messages in the buffer: */
 385         msg.msg_controllen = cmptr->cmsg_len;
 386
 387         iov[0].iov_base = &dummy;
 388         iov[0].iov_len = 1;
 389         msg.msg_iov = iov;
 390         msg.msg_iovlen = 1;
 391
 392         do {
 393                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 394         } while (ret < 0 && errno == EINTR);
 395         if (ret < 0) {
 396                 /*
 397                  * We consider EPIPE and ECONNRESET as expected.
 398                  */
 399                 if (errno != EPIPE && errno != ECONNRESET) {
 400                         PERROR("sendmsg");
 401                 }
 402                 ret = -errno;
 403                 if (ret == -ECONNRESET)
 404                         ret = -EPIPE;
 405         }
 406         return ret;
 407 }
 408
 409 /*
 410  * Recv a message accompanied by fd(s) from a unix socket.
 411  *
 412  * Returns the size of received data, or negative error value.
 413  *
 414  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 415  * actually received in nb_fd.
 416  * Returns -EPIPE on orderly shutdown.
 417  */
 418 ssize_t ustcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 419 {
 420         struct iovec iov[1];
 421         ssize_t ret = 0;
 422         struct cmsghdr *cmsg;
 423         size_t sizeof_fds = nb_fd * sizeof(int);
 424         char recv_fd[CMSG_SPACE(sizeof_fds)];
 425         struct msghdr msg;
 426         char dummy;
 427
 428         memset(&msg, 0, sizeof(msg));
 429
 430         /* Prepare to receive the structures */
 431         iov[0].iov_base = &dummy;
 432         iov[0].iov_len = 1;
 433         msg.msg_iov = iov;
 434         msg.msg_iovlen = 1;
 435         msg.msg_control = recv_fd;
 436         msg.msg_controllen = sizeof(recv_fd);
 437
 438         do {
 439                 ret = recvmsg(sock, &msg, 0);
 440         } while (ret < 0 && errno == EINTR);
 441         if (ret < 0) {
 442                 if (errno != EPIPE && errno != ECONNRESET) {
 443                         PERROR("recvmsg fds");
 444                 }
 445                 ret = -errno;
 446                 if (ret == -ECONNRESET)
 447                         ret = -EPIPE;
 448                 goto end;
 449         }
 450         if (ret == 0) {
 451                 /* orderly shutdown */
 452                 ret = -EPIPE;
 453                 goto end;
 454         }
 455         if (ret != 1) {
 456                 ERR("Error: Received %zd bytes, expected %d\n",
 457                                 ret, 1);
 458                 goto end;
 459         }
 460         if (msg.msg_flags & MSG_CTRUNC) {
 461                 ERR("Error: Control message truncated.\n");
 462                 ret = -1;
 463                 goto end;
 464         }
 465         cmsg = CMSG_FIRSTHDR(&msg);
 466         if (!cmsg) {
 467                 ERR("Error: Invalid control message header\n");
 468                 ret = -1;
 469                 goto end;
 470         }
 471         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 472                 ERR("Didn't received any fd\n");
 473                 ret = -1;
 474                 goto end;
 475         }
 476         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 477                 ERR("Error: Received %zu bytes of ancillary data, expected %zu\n",
 478                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 479                 ret = -1;
 480                 goto end;
 481         }
 482         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 483         ret = sizeof_fds;
 484 end:
 485         return ret;
 486 }
 487
 488 int ustcomm_send_app_msg(int sock, struct ustcomm_ust_msg *lum)
 489 {
 490         ssize_t len;
 491
 492         len = ustcomm_send_unix_sock(sock, lum, sizeof(*lum));
 493         switch (len) {
 494         case sizeof(*lum):
 495                 break;
 496         default:
 497                 if (len < 0) {
 498                         return len;
 499                 } else {
 500                         ERR("incorrect message size: %zd\n", len);
 501                         return -EINVAL;
 502                 }
 503         }
 504         return 0;
 505 }
 506
 507 int ustcomm_recv_app_reply(int sock, struct ustcomm_ust_reply *lur,
 508                           uint32_t expected_handle, uint32_t expected_cmd)
 509 {
 510         ssize_t len;
 511
 512         memset(lur, 0, sizeof(*lur));
 513         len = ustcomm_recv_unix_sock(sock, lur, sizeof(*lur));
 514         switch (len) {
 515         case 0: /* orderly shutdown */
 516                 return -EPIPE;
 517         case sizeof(*lur):
 518                 if (lur->handle != expected_handle) {
 519                         ERR("Unexpected result message handle: "
 520                                 "expected: %u vs received: %u\n",
 521                                 expected_handle, lur->handle);
 522                         return -EINVAL;
 523                 }
 524                 if (lur->cmd != expected_cmd) {
 525                         ERR("Unexpected result message command "
 526                                 "expected: %u vs received: %u\n",
 527                                 expected_cmd, lur->cmd);
 528                         return -EINVAL;
 529                 }
 530                 return lur->ret_code;
 531         default:
 532                 if (len >= 0) {
 533                         ERR("incorrect message size: %zd\n", len);
 534                 }
 535                 return len;
 536         }
 537 }
 538
 539 int ustcomm_send_app_cmd(int sock,
 540                         struct ustcomm_ust_msg *lum,
 541                         struct ustcomm_ust_reply *lur)
 542 {
 543         int ret;
 544
 545         ret = ustcomm_send_app_msg(sock, lum);
 546         if (ret)
 547                 return ret;
 548         ret = ustcomm_recv_app_reply(sock, lur, lum->handle, lum->cmd);
 549         if (ret > 0)
 550                 return -EIO;
 551         return ret;
 552 }
 553
 554 /*
 555  * chan_data is allocated internally if this function returns the
 556  * expected var_len.
 557  */
 558 ssize_t ustcomm_recv_channel_from_sessiond(int sock,
 559                 void **_chan_data, uint64_t var_len,
 560                 int *_wakeup_fd)
 561 {
 562         void *chan_data;
 563         ssize_t len, nr_fd;
 564         int wakeup_fd;
 565
 566         if (var_len > LTTNG_UST_CHANNEL_DATA_MAX_LEN) {
 567                 len = -EINVAL;
 568                 goto error_check;
 569         }
 570         /* Receive variable length data */
 571         chan_data = zmalloc(var_len);
 572         if (!chan_data) {
 573                 len = -ENOMEM;
 574                 goto error_alloc;
 575         }
 576         len = ustcomm_recv_unix_sock(sock, chan_data, var_len);
 577         if (len != var_len) {
 578                 goto error_recv;
 579         }
 580         /* recv wakeup fd */
 581         nr_fd = ustcomm_recv_fds_unix_sock(sock, &wakeup_fd, 1);
 582         if (nr_fd <= 0) {
 583                 if (nr_fd < 0) {
 584                         len = nr_fd;
 585                         goto error_recv;
 586                 } else {
 587                         len = -EIO;
 588                         goto error_recv;
 589                 }
 590         }
 591         *_wakeup_fd = wakeup_fd;
 592         *_chan_data = chan_data;
 593         return len;
 594
 595 error_recv:
 596         free(chan_data);
 597 error_alloc:
 598 error_check:
 599         return len;
 600 }
 601
 602 int ustcomm_recv_stream_from_sessiond(int sock,
 603                 uint64_t *memory_map_size,
 604                 int *shm_fd, int *wakeup_fd)
 605 {
 606         ssize_t len;
 607         int ret;
 608         int fds[2];
 609
 610         /* recv shm fd and wakeup fd */
 611         len = ustcomm_recv_fds_unix_sock(sock, fds, 2);
 612         if (len <= 0) {
 613                 if (len < 0) {
 614                         ret = len;
 615                         goto error;
 616                 } else {
 617                         ret = -EIO;
 618                         goto error;
 619                 }
 620         }
 621         *shm_fd = fds[0];
 622         *wakeup_fd = fds[1];
 623         return 0;
 624
 625 error:
 626         return ret;
 627 }
 628
 629 /*
 630  * Returns 0 on success, negative error value on error.
 631  */
 632 int ustcomm_send_reg_msg(int sock,
 633                 enum ustctl_socket_type type,
 634                 uint32_t bits_per_long,
 635                 uint32_t uint8_t_alignment,
 636                 uint32_t uint16_t_alignment,
 637                 uint32_t uint32_t_alignment,
 638                 uint32_t uint64_t_alignment,
 639                 uint32_t long_alignment)
 640 {
 641         ssize_t len;
 642         struct ustctl_reg_msg reg_msg;
 643
 644         reg_msg.magic = LTTNG_UST_COMM_MAGIC;
 645         reg_msg.major = LTTNG_UST_ABI_MAJOR_VERSION;
 646         reg_msg.minor = LTTNG_UST_ABI_MINOR_VERSION;
 647         reg_msg.pid = getpid();
 648         reg_msg.ppid = getppid();
 649         reg_msg.uid = getuid();
 650         reg_msg.gid = getgid();
 651         reg_msg.bits_per_long = bits_per_long;
 652         reg_msg.uint8_t_alignment = uint8_t_alignment;
 653         reg_msg.uint16_t_alignment = uint16_t_alignment;
 654         reg_msg.uint32_t_alignment = uint32_t_alignment;
 655         reg_msg.uint64_t_alignment = uint64_t_alignment;
 656         reg_msg.long_alignment = long_alignment;
 657         reg_msg.socket_type = type;
 658         lttng_ust_getprocname(reg_msg.name);
 659         memset(reg_msg.padding, 0, sizeof(reg_msg.padding));
 660
 661         len = ustcomm_send_unix_sock(sock, &reg_msg, sizeof(reg_msg));
 662         if (len > 0 && len != sizeof(reg_msg))
 663                 return -EIO;
 664         if (len < 0)
 665                 return len;
 666         return 0;
 667 }
 668
 669 static
 670 int serialize_string_encoding(enum ustctl_string_encodings *ue,
 671                 enum lttng_string_encodings le)
 672 {
 673         switch (le) {
 674         case lttng_encode_none:
 675                 *ue = ustctl_encode_none;
 676                 break;
 677         case lttng_encode_UTF8:
 678                 *ue = ustctl_encode_UTF8;
 679                 break;
 680         case lttng_encode_ASCII:
 681                 *ue = ustctl_encode_ASCII;
 682                 break;
 683         default:
 684                 return -EINVAL;
 685         }
 686         return 0;
 687 }
 688
 689 static
 690 int serialize_basic_type(enum ustctl_abstract_types *uatype,
 691                 enum lttng_abstract_types atype,
 692                 union _ustctl_basic_type *ubt,
 693                 const union _lttng_basic_type *lbt)
 694 {
 695         switch (atype) {
 696         case atype_integer:
 697         {
 698                 struct ustctl_integer_type *uit;
 699                 const struct lttng_integer_type *lit;
 700
 701                 uit = &ubt->integer;
 702                 lit = &lbt->integer;
 703                 uit->size = lit->size;
 704                 uit->signedness = lit->signedness;
 705                 uit->reverse_byte_order = lit->reverse_byte_order;
 706                 uit->base = lit->base;
 707                 if (serialize_string_encoding(&uit->encoding, lit->encoding))
 708                         return -EINVAL;
 709                 uit->alignment = lit->alignment;
 710                 *uatype = ustctl_atype_integer;
 711                 break;
 712         }
 713         case atype_string:
 714         {
 715                 if (serialize_string_encoding(&ubt->string.encoding,
 716                                 lbt->string.encoding))
 717                         return -EINVAL;
 718                 *uatype = ustctl_atype_string;
 719                 break;
 720         }
 721         case atype_float:
 722         {
 723                 struct ustctl_float_type *uft;
 724                 const struct lttng_float_type *lft;
 725
 726                 uft = &ubt->_float;
 727                 lft = &lbt->_float;
 728                 uft->exp_dig = lft->exp_dig;
 729                 uft->mant_dig = lft->mant_dig;
 730                 uft->alignment = lft->alignment;
 731                 uft->reverse_byte_order = lft->reverse_byte_order;
 732                 *uatype = ustctl_atype_float;
 733                 break;
 734         }
 735         case atype_enum:
 736         case atype_array:
 737         case atype_sequence:
 738         default:
 739                 return -EINVAL;
 740         }
 741         return 0;
 742 }
 743
 744 static
 745 int serialize_one_type(struct ustctl_type *ut, const struct lttng_type *lt)
 746 {
 747         int ret;
 748
 749         switch (lt->atype) {
 750         case atype_integer:
 751         case atype_float:
 752         case atype_string:
 753                 ret = serialize_basic_type(&ut->atype, lt->atype,
 754                         &ut->u.basic, &lt->u.basic);
 755                 if (ret)
 756                         return ret;
 757                 break;
 758         case atype_array:
 759         {
 760                 struct ustctl_basic_type *ubt;
 761                 const struct lttng_basic_type *lbt;
 762                 int ret;
 763
 764                 ubt = &ut->u.array.elem_type;
 765                 lbt = &lt->u.array.elem_type;
 766                 ut->u.array.length = lt->u.array.length;
 767                 ret = serialize_basic_type(&ubt->atype, lbt->atype,
 768                         &ubt->u.basic, &lbt->u.basic);
 769                 if (ret)
 770                         return -EINVAL;
 771                 ut->atype = ustctl_atype_array;
 772                 break;
 773         }
 774         case atype_sequence:
 775         {
 776                 struct ustctl_basic_type *ubt;
 777                 const struct lttng_basic_type *lbt;
 778                 int ret;
 779
 780                 ubt = &ut->u.sequence.length_type;
 781                 lbt = &lt->u.sequence.length_type;
 782                 ret = serialize_basic_type(&ubt->atype, lbt->atype,
 783                         &ubt->u.basic, &lbt->u.basic);
 784                 if (ret)
 785                         return -EINVAL;
 786                 ubt = &ut->u.sequence.elem_type;
 787                 lbt = &lt->u.sequence.elem_type;
 788                 ret = serialize_basic_type(&ubt->atype, lbt->atype,
 789                         &ubt->u.basic, &lbt->u.basic);
 790                 if (ret)
 791                         return -EINVAL;
 792                 ut->atype = ustctl_atype_sequence;
 793                 break;
 794         }
 795         case atype_enum:
 796         default:
 797                 return -EINVAL;
 798         }
 799         return 0;
 800 }
 801
 802 static
 803 int serialize_fields(size_t *_nr_write_fields,
 804                 struct ustctl_field **ustctl_fields,
 805                 size_t nr_fields,
 806                 const struct lttng_event_field *lttng_fields)
 807 {
 808         struct ustctl_field *fields;
 809         int i, ret;
 810         size_t nr_write_fields = 0;
 811
 812         fields = zmalloc(nr_fields * sizeof(*fields));
 813         if (!fields)
 814                 return -ENOMEM;
 815
 816         for (i = 0; i < nr_fields; i++) {
 817                 struct ustctl_field *f;
 818                 const struct lttng_event_field *lf;
 819
 820                 f = &fields[nr_write_fields];
 821                 lf = &lttng_fields[i];
 822
 823                 /* skip 'nowrite' fields */
 824                 if (lf->nowrite)
 825                         continue;
 826                 strncpy(f->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
 827                 f->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 828                 ret = serialize_one_type(&f->type, &lf->type);
 829                 if (ret)
 830                         goto error_type;
 831                 nr_write_fields++;
 832         }
 833
 834         *_nr_write_fields = nr_write_fields;
 835         *ustctl_fields = fields;
 836         return 0;
 837
 838 error_type:
 839         free(fields);
 840         return ret;
 841 }
 842
 843 static
 844 int serialize_ctx_fields(size_t *_nr_write_fields,
 845                 struct ustctl_field **ustctl_fields,
 846                 size_t nr_fields,
 847                 const struct lttng_ctx_field *lttng_fields)
 848 {
 849         struct ustctl_field *fields;
 850         int i, ret;
 851         size_t nr_write_fields = 0;
 852
 853         fields = zmalloc(nr_fields * sizeof(*fields));
 854         if (!fields)
 855                 return -ENOMEM;
 856
 857         for (i = 0; i < nr_fields; i++) {
 858                 struct ustctl_field *f;
 859                 const struct lttng_event_field *lf;
 860
 861                 f = &fields[nr_write_fields];
 862                 lf = &lttng_fields[i].event_field;
 863
 864                 /* skip 'nowrite' fields */
 865                 if (lf->nowrite)
 866                         continue;
 867                 strncpy(f->name, lf->name, LTTNG_UST_SYM_NAME_LEN);
 868                 f->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 869                 ret = serialize_one_type(&f->type, &lf->type);
 870                 if (ret)
 871                         goto error_type;
 872                 nr_write_fields++;
 873         }
 874
 875         *_nr_write_fields = nr_write_fields;
 876         *ustctl_fields = fields;
 877         return 0;
 878
 879 error_type:
 880         free(fields);
 881         return ret;
 882 }
 883
 884 /*
 885  * Returns 0 on success, negative error value on error.
 886  */
 887 int ustcomm_register_event(int sock,
 888         int session_objd,               /* session descriptor */
 889         int channel_objd,               /* channel descriptor */
 890         const char *event_name,         /* event name (input) */
 891         int loglevel,
 892         const char *signature,          /* event signature (input) */
 893         size_t nr_fields,               /* fields */
 894         const struct lttng_event_field *lttng_fields,
 895         const char *model_emf_uri,
 896         uint32_t *id)                   /* event id (output) */
 897 {
 898         ssize_t len;
 899         struct {
 900                 struct ustcomm_notify_hdr header;
 901                 struct ustcomm_notify_event_msg m;
 902         } msg;
 903         struct {
 904                 struct ustcomm_notify_hdr header;
 905                 struct ustcomm_notify_event_reply r;
 906         } reply;
 907         size_t signature_len, fields_len, model_emf_uri_len;
 908         struct ustctl_field *fields = NULL;
 909         size_t nr_write_fields = 0;
 910         int ret;
 911
 912         memset(&msg, 0, sizeof(msg));
 913         msg.header.notify_cmd = USTCTL_NOTIFY_CMD_EVENT;
 914         msg.m.session_objd = session_objd;
 915         msg.m.channel_objd = channel_objd;
 916         strncpy(msg.m.event_name, event_name, LTTNG_UST_SYM_NAME_LEN);
 917         msg.m.event_name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 918         msg.m.loglevel = loglevel;
 919         signature_len = strlen(signature) + 1;
 920         msg.m.signature_len = signature_len;
 921
 922         /* Calculate fields len, serialize fields. */
 923         if (nr_fields > 0) {
 924                 ret = serialize_fields(&nr_write_fields, &fields,
 925                                 nr_fields, lttng_fields);
 926                 if (ret)
 927                         return ret;
 928         }
 929
 930         fields_len = sizeof(*fields) * nr_write_fields;
 931         msg.m.fields_len = fields_len;
 932         if (model_emf_uri) {
 933                 model_emf_uri_len = strlen(model_emf_uri) + 1;
 934         } else {
 935                 model_emf_uri_len = 0;
 936         }
 937         msg.m.model_emf_uri_len = model_emf_uri_len;
 938         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
 939         if (len > 0 && len != sizeof(msg)) {
 940                 free(fields);
 941                 return -EIO;
 942         }
 943         if (len < 0) {
 944                 free(fields);
 945                 return len;
 946         }
 947
 948         /* send signature */
 949         len = ustcomm_send_unix_sock(sock, signature, signature_len);
 950         if (len > 0 && len != signature_len) {
 951                 free(fields);
 952                 return -EIO;
 953         }
 954         if (len < 0) {
 955                 free(fields);
 956                 return len;
 957         }
 958
 959         /* send fields */
 960         if (fields_len > 0) {
 961                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
 962                 free(fields);
 963                 if (len > 0 && len != fields_len) {
 964                         return -EIO;
 965                 }
 966                 if (len < 0) {
 967                         return len;
 968                 }
 969         } else {
 970                 free(fields);
 971         }
 972
 973         if (model_emf_uri_len) {
 974                 /* send model_emf_uri */
 975                 len = ustcomm_send_unix_sock(sock, model_emf_uri,
 976                                 model_emf_uri_len);
 977                 if (len > 0 && len != model_emf_uri_len)
 978                         return -EIO;
 979                 if (len < 0)
 980                         return len;
 981         }
 982
 983         /* receive reply */
 984         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
 985         switch (len) {
 986         case 0: /* orderly shutdown */
 987                 return -EPIPE;
 988         case sizeof(reply):
 989                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
 990                         ERR("Unexpected result message command "
 991                                 "expected: %u vs received: %u\n",
 992                                 msg.header.notify_cmd, reply.header.notify_cmd);
 993                         return -EINVAL;
 994                 }
 995                 if (reply.r.ret_code > 0)
 996                         return -EINVAL;
 997                 if (reply.r.ret_code < 0)
 998                         return reply.r.ret_code;
 999                 *id = reply.r.event_id;
1000                 DBG("Sent register event notification for name \"%s\": ret_code %d, event_id %u\n",
1001                         event_name, reply.r.ret_code, reply.r.event_id);
1002                 return 0;
1003         default:
1004                 if (len < 0) {
1005                         /* Transport level error */
1006                         if (errno == EPIPE || errno == ECONNRESET)
1007                                 len = -errno;
1008                         return len;
1009                 } else {
1010                         ERR("incorrect message size: %zd\n", len);
1011                         return len;
1012                 }
1013         }
1014 }
1015
1016 /*
1017  * Returns 0 on success, negative error value on error.
1018  * Returns -EPIPE or -ECONNRESET if other end has hung up.
1019  */
1020 int ustcomm_register_channel(int sock,
1021         int session_objd,               /* session descriptor */
1022         int channel_objd,               /* channel descriptor */
1023         size_t nr_ctx_fields,
1024         const struct lttng_ctx_field *ctx_fields,
1025         uint32_t *chan_id,              /* channel id (output) */
1026         int *header_type)               /* header type (output) */
1027 {
1028         ssize_t len;
1029         struct {
1030                 struct ustcomm_notify_hdr header;
1031                 struct ustcomm_notify_channel_msg m;
1032         } msg;
1033         struct {
1034                 struct ustcomm_notify_hdr header;
1035                 struct ustcomm_notify_channel_reply r;
1036         } reply;
1037         size_t fields_len;
1038         struct ustctl_field *fields = NULL;
1039         int ret;
1040         size_t nr_write_fields = 0;
1041
1042         memset(&msg, 0, sizeof(msg));
1043         msg.header.notify_cmd = USTCTL_NOTIFY_CMD_CHANNEL;
1044         msg.m.session_objd = session_objd;
1045         msg.m.channel_objd = channel_objd;
1046
1047         /* Calculate fields len, serialize fields. */
1048         if (nr_ctx_fields > 0) {
1049                 ret = serialize_ctx_fields(&nr_write_fields, &fields,
1050                                 nr_ctx_fields, ctx_fields);
1051                 if (ret)
1052                         return ret;
1053         }
1054
1055         fields_len = sizeof(*fields) * nr_write_fields;
1056         msg.m.ctx_fields_len = fields_len;
1057         len = ustcomm_send_unix_sock(sock, &msg, sizeof(msg));
1058         if (len > 0 && len != sizeof(msg)) {
1059                 free(fields);
1060                 return -EIO;
1061         }
1062         if (len < 0) {
1063                 free(fields);
1064                 return len;
1065         }
1066
1067         /* send fields */
1068         if (fields_len > 0) {
1069                 len = ustcomm_send_unix_sock(sock, fields, fields_len);
1070                 free(fields);
1071                 if (len > 0 && len != fields_len) {
1072                         return -EIO;
1073                 }
1074                 if (len < 0) {
1075                         return len;
1076                 }
1077         } else {
1078                 free(fields);
1079         }
1080
1081         len = ustcomm_recv_unix_sock(sock, &reply, sizeof(reply));
1082         switch (len) {
1083         case 0: /* orderly shutdown */
1084                 return -EPIPE;
1085         case sizeof(reply):
1086                 if (reply.header.notify_cmd != msg.header.notify_cmd) {
1087                         ERR("Unexpected result message command "
1088                                 "expected: %u vs received: %u\n",
1089                                 msg.header.notify_cmd, reply.header.notify_cmd);
1090                         return -EINVAL;
1091                 }
1092                 if (reply.r.ret_code > 0)
1093                         return -EINVAL;
1094                 if (reply.r.ret_code < 0)
1095                         return reply.r.ret_code;
1096                 *chan_id = reply.r.chan_id;
1097                 switch (reply.r.header_type) {
1098                 case 1:
1099                 case 2:
1100                         *header_type = reply.r.header_type;
1101                         break;
1102                 default:
1103                         ERR("Unexpected channel header type %u\n",
1104                                 reply.r.header_type);
1105                         return -EINVAL;
1106                 }
1107                 DBG("Sent register channel notification: chan_id %d, header_type %d\n",
1108                         reply.r.chan_id, reply.r.header_type);
1109                 return 0;
1110         default:
1111                 if (len < 0) {
1112                         /* Transport level error */
1113                         if (errno == EPIPE || errno == ECONNRESET)
1114                                 len = -errno;
1115                         return len;
1116                 } else {
1117                         ERR("incorrect message size: %zd\n", len);
1118                         return len;
1119                 }
1120         }
1121 }
1122
1123 /*
1124  * Set socket reciving timeout.
1125  */
1126 int ustcomm_setsockopt_rcv_timeout(int sock, unsigned int msec)
1127 {
1128         int ret;
1129         struct timeval tv;
1130
1131         tv.tv_sec = msec / 1000;
1132         tv.tv_usec = (msec * 1000 % 1000000);
1133
1134         ret = setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
1135         if (ret < 0) {
1136                 PERROR("setsockopt SO_RCVTIMEO");
1137                 ret = -errno;
1138         }
1139
1140         return ret;
1141 }
1142
1143 /*
1144  * Set socket sending timeout.
1145  */
1146 int ustcomm_setsockopt_snd_timeout(int sock, unsigned int msec)
1147 {
1148         int ret;
1149         struct timeval tv;
1150
1151         tv.tv_sec = msec / 1000;
1152         tv.tv_usec = (msec * 1000) % 1000000;
1153
1154         ret = setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
1155         if (ret < 0) {
1156                 PERROR("setsockopt SO_SNDTIMEO");
1157                 ret = -errno;
1158         }
1159
1160         return ret;
1161 }