liblttng-sessiond-comm/lttng-sessiond-comm.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the Free
   7  * Software Foundation; only version 2 of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  16  * Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <assert.h>
  21 #include <limits.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/stat.h>
  26 #include <sys/types.h>
  27 #include <sys/un.h>
  28 #include <unistd.h>
  29 #include <errno.h>
  30
  31 #include <lttng-sessiond-comm.h>
  32
  33 /*
  34  * Human readable error message.
  35  */
  36 static const char *lttcomm_readable_code[] = {
  37         [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
  38         [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
  39         [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
  40         [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
  41         [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
  42         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
  43         [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
  44         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
  45         [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
  46         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
  47         [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
  48         [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
  49         [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
  50         [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
  51         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
  52         [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
  53         [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
  54         [ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
  55         [ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
  56         [ LTTCOMM_ERR_INDEX(LTTCOMM_EPERM) ] = "Permission denied",
  57         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
  58         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
  59         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  60         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  73         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  74         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  75         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  76         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
  77         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
  78         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
  79         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
  80         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
  81         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
  82         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
  83         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
  84         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
  85         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
  86         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
  87         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
  88         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
  89         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
  90         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
  91         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
  92         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
  93         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
  94         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
  95         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
  96         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
  97         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
  98         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
  99         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
 100         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
 101         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
 102         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 103         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 104         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 105         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 106         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 107         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 108         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 109         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 110         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 111         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 112         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 113 };
 114
 115 /*
 116  * Return ptr to string representing a human readable error code from the
 117  * lttcomm_return_code enum.
 118  *
 119  * These code MUST be negative in other to treat that as an error value.
 120  */
 121 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 122 {
 123         int tmp_code = -code;
 124
 125         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 126                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 127         }
 128
 129         return "Unknown error code";
 130 }
 131
 132 /*
 133  * Connect to unix socket using the path name.
 134  */
 135 int lttcomm_connect_unix_sock(const char *pathname)
 136 {
 137         struct sockaddr_un sun;
 138         int fd;
 139         int ret;
 140
 141         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 142         if (fd < 0) {
 143                 perror("socket");
 144                 ret = fd;
 145                 goto error;
 146         }
 147
 148         memset(&sun, 0, sizeof(sun));
 149         sun.sun_family = AF_UNIX;
 150         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 151         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 152
 153         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 154         if (ret < 0) {
 155                 /*
 156                  * Don't print message on connect error, because connect is used in
 157                  * normal execution to detect if sessiond is alive.
 158                  */
 159                 goto error_connect;
 160         }
 161
 162         return fd;
 163
 164 error_connect:
 165         close(fd);
 166 error:
 167         return ret;
 168 }
 169
 170 /*
 171  * Do an accept(2) on the sock and return the new file descriptor. The socket
 172  * MUST be bind(2) before.
 173  */
 174 int lttcomm_accept_unix_sock(int sock)
 175 {
 176         int new_fd;
 177         struct sockaddr_un sun;
 178         socklen_t len = 0;
 179
 180         /* Blocking call */
 181         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 182         if (new_fd < 0) {
 183                 perror("accept");
 184         }
 185
 186         return new_fd;
 187 }
 188
 189 /*
 190  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 191  * and return the fd.
 192  */
 193 int lttcomm_create_unix_sock(const char *pathname)
 194 {
 195         struct sockaddr_un sun;
 196         int fd;
 197         int ret = -1;
 198
 199         /* Create server socket */
 200         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 201                 perror("socket");
 202                 goto error;
 203         }
 204
 205         memset(&sun, 0, sizeof(sun));
 206         sun.sun_family = AF_UNIX;
 207         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 208         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 209
 210         /* Unlink the old file if present */
 211         (void) unlink(pathname);
 212         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 213         if (ret < 0) {
 214                 perror("bind");
 215                 goto error;
 216         }
 217
 218         return fd;
 219
 220 error:
 221         return ret;
 222 }
 223
 224 /*
 225  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 226  */
 227 int lttcomm_listen_unix_sock(int sock)
 228 {
 229         int ret;
 230
 231         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 232         if (ret < 0) {
 233                 perror("listen");
 234         }
 235
 236         return ret;
 237 }
 238
 239 /*
 240  * Receive data of size len in put that data into the buf param. Using recvmsg
 241  * API.
 242  *
 243  * Return the size of received data.
 244  */
 245 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 246 {
 247         struct msghdr msg = { 0 };
 248         struct iovec iov[1];
 249         ssize_t ret = -1;
 250
 251         iov[0].iov_base = buf;
 252         iov[0].iov_len = len;
 253         msg.msg_iov = iov;
 254         msg.msg_iovlen = 1;
 255
 256         ret = recvmsg(sock, &msg, 0);
 257         if (ret < 0) {
 258                 perror("recvmsg");
 259         }
 260
 261         return ret;
 262 }
 263
 264 /*
 265  * Send buf data of size len. Using sendmsg API.
 266  *
 267  * Return the size of sent data.
 268  */
 269 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 270 {
 271         struct msghdr msg = { 0 };
 272         struct iovec iov[1];
 273         ssize_t ret = -1;
 274
 275         iov[0].iov_base = buf;
 276         iov[0].iov_len = len;
 277         msg.msg_iov = iov;
 278         msg.msg_iovlen = 1;
 279
 280         ret = sendmsg(sock, &msg, 0);
 281         if (ret < 0) {
 282                 perror("sendmsg");
 283         }
 284
 285         return ret;
 286 }
 287
 288 /*
 289  * Shutdown cleanly a unix socket.
 290  */
 291 int lttcomm_close_unix_sock(int sock)
 292 {
 293         int ret;
 294
 295         /* Shutdown receptions and transmissions */
 296         ret = shutdown(sock, SHUT_RDWR);
 297         if (ret < 0) {
 298                 perror("shutdown");
 299         }
 300
 301         return ret;
 302 }
 303
 304 /*
 305  * Send a message accompanied by fd(s) over a unix socket.
 306  *
 307  * Returns the size of data sent, or negative error value.
 308  */
 309 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 310 {
 311         struct msghdr msg = { 0 };
 312         struct cmsghdr *cmptr;
 313         struct iovec iov[1];
 314         ssize_t ret = -1;
 315         unsigned int sizeof_fds = nb_fd * sizeof(int);
 316         char tmp[CMSG_SPACE(sizeof_fds)];
 317         char dummy = 0;
 318
 319         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 320                 return -EINVAL;
 321
 322         msg.msg_control = (caddr_t)tmp;
 323         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 324
 325         cmptr = CMSG_FIRSTHDR(&msg);
 326         cmptr->cmsg_level = SOL_SOCKET;
 327         cmptr->cmsg_type = SCM_RIGHTS;
 328         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 329         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 330         /* Sum of the length of all control messages in the buffer: */
 331         msg.msg_controllen = cmptr->cmsg_len;
 332
 333         iov[0].iov_base = &dummy;
 334         iov[0].iov_len = 1;
 335         msg.msg_iov = iov;
 336         msg.msg_iovlen = 1;
 337
 338         ret = sendmsg(sock, &msg, 0);
 339         if (ret < 0) {
 340                 perror("sendmsg");
 341         }
 342         return ret;
 343 }
 344
 345 /*
 346  * Recv a message accompanied by fd(s) from a unix socket.
 347  *
 348  * Returns the size of received data, or negative error value.
 349  *
 350  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 351  * actually received in nb_fd.
 352  */
 353 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 354 {
 355         struct iovec iov[1];
 356         ssize_t ret = 0;
 357         struct cmsghdr *cmsg;
 358         size_t sizeof_fds = nb_fd * sizeof(int);
 359         char recv_fd[CMSG_SPACE(sizeof_fds)];
 360         struct msghdr msg = { 0 };
 361         char dummy;
 362
 363         /* Prepare to receive the structures */
 364         iov[0].iov_base = &dummy;
 365         iov[0].iov_len = 1;
 366         msg.msg_iov = iov;
 367         msg.msg_iovlen = 1;
 368         msg.msg_control = recv_fd;
 369         msg.msg_controllen = sizeof(recv_fd);
 370
 371         ret = recvmsg(sock, &msg, 0);
 372         if (ret < 0) {
 373                 perror("recvmsg fds");
 374                 goto end;
 375         }
 376         if (ret != 1) {
 377                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 378                                 ret, 1);
 379                 goto end;
 380         }
 381         if (msg.msg_flags & MSG_CTRUNC) {
 382                 fprintf(stderr, "Error: Control message truncated.\n");
 383                 ret = -1;
 384                 goto end;
 385         }
 386         cmsg = CMSG_FIRSTHDR(&msg);
 387         if (!cmsg) {
 388                 fprintf(stderr, "Error: Invalid control message header\n");
 389                 ret = -1;
 390                 goto end;
 391         }
 392         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 393                 fprintf(stderr, "Didn't received any fd\n");
 394                 ret = -1;
 395                 goto end;
 396         }
 397         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 398                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 399                                 cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
 400                 ret = -1;
 401                 goto end;
 402         }
 403         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 404         ret = sizeof_fds;
 405 end:
 406         return ret;
 407 }
 408
 409 /*
 410  * Send a message with credentials over a unix socket.
 411  *
 412  * Returns the size of data sent, or negative error value.
 413  */
 414 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 415 {
 416         struct msghdr msg = { 0 };
 417         struct cmsghdr *cmptr;
 418         struct iovec iov[1];
 419         ssize_t ret = -1;
 420         struct ucred *creds;
 421         size_t sizeof_cred = sizeof(struct ucred);
 422         char anc_buf[CMSG_SPACE(sizeof_cred)];
 423
 424         iov[0].iov_base = buf;
 425         iov[0].iov_len = len;
 426         msg.msg_iov = iov;
 427         msg.msg_iovlen = 1;
 428
 429         msg.msg_control = (caddr_t) anc_buf;
 430         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 431
 432         cmptr = CMSG_FIRSTHDR(&msg);
 433         cmptr->cmsg_level = SOL_SOCKET;
 434         cmptr->cmsg_type = SCM_CREDENTIALS;
 435         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 436
 437         creds = (struct ucred *) CMSG_DATA(cmptr);
 438
 439         creds->uid = geteuid();
 440         creds->gid = getegid();
 441         creds->pid = getpid();
 442
 443         ret = sendmsg(sock, &msg, 0);
 444         if (ret < 0) {
 445                 perror("sendmsg");
 446         }
 447
 448         return ret;
 449 }
 450
 451 /*
 452  * Recv a message accompanied with credentials from a unix socket.
 453  *
 454  * Returns the size of received data, or negative error value.
 455  */
 456 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 457                 struct ucred *creds)
 458 {
 459         struct msghdr msg = { 0 };
 460         struct cmsghdr *cmptr;
 461         struct iovec iov[1];
 462         ssize_t ret;
 463         size_t sizeof_cred = sizeof(struct ucred);
 464         char anc_buf[CMSG_SPACE(sizeof_cred)];
 465
 466         /* Not allowed */
 467         if (creds == NULL) {
 468                 ret = -1;
 469                 goto end;
 470         }
 471
 472         /* Prepare to receive the structures */
 473         iov[0].iov_base = buf;
 474         iov[0].iov_len = len;
 475         msg.msg_iov = iov;
 476         msg.msg_iovlen = 1;
 477
 478         msg.msg_control = anc_buf;
 479         msg.msg_controllen = sizeof(anc_buf);
 480
 481         ret = recvmsg(sock, &msg, 0);
 482         if (ret < 0) {
 483                 perror("recvmsg fds");
 484                 goto end;
 485         }
 486
 487         if (msg.msg_flags & MSG_CTRUNC) {
 488                 fprintf(stderr, "Error: Control message truncated.\n");
 489                 ret = -1;
 490                 goto end;
 491         }
 492
 493         cmptr = CMSG_FIRSTHDR(&msg);
 494         if (cmptr == NULL) {
 495                 fprintf(stderr, "Error: Invalid control message header\n");
 496                 ret = -1;
 497                 goto end;
 498         }
 499
 500         if (cmptr->cmsg_level != SOL_SOCKET ||
 501                         cmptr->cmsg_type != SCM_CREDENTIALS) {
 502                 fprintf(stderr, "Didn't received any credentials\n");
 503                 ret = -1;
 504                 goto end;
 505         }
 506
 507         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 508                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 509                                 cmptr->cmsg_len, CMSG_LEN(sizeof_cred));
 510                 ret = -1;
 511                 goto end;
 512         }
 513
 514         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 515
 516 end:
 517         return ret;
 518 }
 519
 520 /*
 521  * Set socket option to use credentials passing.
 522  */
 523 int lttcomm_setsockopt_creds_unix_sock(int sock)
 524 {
 525         int ret, on = 1;
 526
 527         /* Set socket for credentials retrieval */
 528         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 529         if (ret < 0) {
 530                 perror("setsockopt creds unix sock");
 531         }
 532
 533         return ret;
 534 }