src/common/sessiond-comm/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 <common/defaults.h>
  32
  33 #include "sessiond-comm.h"
  34
  35 /*
  36  * Human readable error message.
  37  */
  38 static const char *lttcomm_readable_code[] = {
  39         [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
  40         [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
  41         [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
  42         [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
  43         [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
  44         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
  45         [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
  46         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
  47         [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
  48         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
  49         [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
  50         [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_DIR_FAIL) ] = "Create directory failed",
  51         [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
  52         [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
  53         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
  54         [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
  55         [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
  56         [ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
  57         [ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
  58         [ LTTCOMM_ERR_INDEX(LTTCOMM_EPERM) ] = "Permission denied",
  59         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
  60         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_VERSION) ] = "Kernel tracer version is not compatible",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  73         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  74         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  75         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  76         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  77         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  78         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  79         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CALIBRATE_FAIL) ] = "UST calibration failed",
  80         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_VERSION) ] = "UST tracer version is not compatible",
  81         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
  82         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
  83         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
  84         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
  85         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
  86         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
  87         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
  88         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
  89         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
  90         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
  91         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
  92         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
  93         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
  94         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
  95         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
  96         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
  97         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
  98         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
  99         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
 100         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
 101         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
 102         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
 103         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_INVAL)] = "UST invalid context",
 104         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
 105         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
 106         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
 107         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
 108         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 109         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 110         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 111         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 112         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 113         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 114         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 115         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 116         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 117         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 118         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 119 };
 120
 121 /*
 122  * Return ptr to string representing a human readable error code from the
 123  * lttcomm_return_code enum.
 124  *
 125  * These code MUST be negative in other to treat that as an error value.
 126  */
 127 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 128 {
 129         int tmp_code = -code;
 130
 131         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 132                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 133         }
 134
 135         return "Unknown error code";
 136 }
 137
 138 /*
 139  * Connect to unix socket using the path name.
 140  */
 141 int lttcomm_connect_unix_sock(const char *pathname)
 142 {
 143         struct sockaddr_un sun;
 144         int fd;
 145         int ret;
 146
 147         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 148         if (fd < 0) {
 149                 perror("socket");
 150                 ret = fd;
 151                 goto error;
 152         }
 153
 154         memset(&sun, 0, sizeof(sun));
 155         sun.sun_family = AF_UNIX;
 156         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 157         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 158
 159         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 160         if (ret < 0) {
 161                 /*
 162                  * Don't print message on connect error, because connect is used in
 163                  * normal execution to detect if sessiond is alive.
 164                  */
 165                 goto error_connect;
 166         }
 167
 168         return fd;
 169
 170 error_connect:
 171         close(fd);
 172 error:
 173         return ret;
 174 }
 175
 176 /*
 177  * Do an accept(2) on the sock and return the new file descriptor. The socket
 178  * MUST be bind(2) before.
 179  */
 180 int lttcomm_accept_unix_sock(int sock)
 181 {
 182         int new_fd;
 183         struct sockaddr_un sun;
 184         socklen_t len = 0;
 185
 186         /* Blocking call */
 187         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 188         if (new_fd < 0) {
 189                 perror("accept");
 190         }
 191
 192         return new_fd;
 193 }
 194
 195 /*
 196  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 197  * and return the fd.
 198  */
 199 int lttcomm_create_unix_sock(const char *pathname)
 200 {
 201         struct sockaddr_un sun;
 202         int fd;
 203         int ret = -1;
 204
 205         /* Create server socket */
 206         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 207                 perror("socket");
 208                 goto error;
 209         }
 210
 211         memset(&sun, 0, sizeof(sun));
 212         sun.sun_family = AF_UNIX;
 213         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 214         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 215
 216         /* Unlink the old file if present */
 217         (void) unlink(pathname);
 218         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 219         if (ret < 0) {
 220                 perror("bind");
 221                 goto error;
 222         }
 223
 224         return fd;
 225
 226 error:
 227         return ret;
 228 }
 229
 230 /*
 231  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 232  */
 233 int lttcomm_listen_unix_sock(int sock)
 234 {
 235         int ret;
 236
 237         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 238         if (ret < 0) {
 239                 perror("listen");
 240         }
 241
 242         return ret;
 243 }
 244
 245 /*
 246  * Receive data of size len in put that data into the buf param. Using recvmsg
 247  * API.
 248  *
 249  * Return the size of received data.
 250  */
 251 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 252 {
 253         struct msghdr msg;
 254         struct iovec iov[1];
 255         ssize_t ret = -1;
 256
 257         memset(&msg, 0, sizeof(msg));
 258
 259         iov[0].iov_base = buf;
 260         iov[0].iov_len = len;
 261         msg.msg_iov = iov;
 262         msg.msg_iovlen = 1;
 263
 264         ret = recvmsg(sock, &msg, MSG_WAITALL);
 265         if (ret < 0) {
 266                 perror("recvmsg");
 267         }
 268
 269         return ret;
 270 }
 271
 272 /*
 273  * Send buf data of size len. Using sendmsg API.
 274  *
 275  * Return the size of sent data.
 276  */
 277 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 278 {
 279         struct msghdr msg;
 280         struct iovec iov[1];
 281         ssize_t ret = -1;
 282
 283         memset(&msg, 0, sizeof(msg));
 284
 285         iov[0].iov_base = buf;
 286         iov[0].iov_len = len;
 287         msg.msg_iov = iov;
 288         msg.msg_iovlen = 1;
 289
 290         ret = sendmsg(sock, &msg, 0);
 291         if (ret < 0) {
 292                 perror("sendmsg");
 293         }
 294
 295         return ret;
 296 }
 297
 298 /*
 299  * Shutdown cleanly a unix socket.
 300  */
 301 int lttcomm_close_unix_sock(int sock)
 302 {
 303         int ret;
 304
 305         /* Shutdown receptions and transmissions */
 306         ret = shutdown(sock, SHUT_RDWR);
 307         if (ret < 0) {
 308                 perror("shutdown");
 309         }
 310
 311         return ret;
 312 }
 313
 314 /*
 315  * Send a message accompanied by fd(s) over a unix socket.
 316  *
 317  * Returns the size of data sent, or negative error value.
 318  */
 319 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 320 {
 321         struct msghdr msg;
 322         struct cmsghdr *cmptr;
 323         struct iovec iov[1];
 324         ssize_t ret = -1;
 325         unsigned int sizeof_fds = nb_fd * sizeof(int);
 326         char tmp[CMSG_SPACE(sizeof_fds)];
 327         char dummy = 0;
 328
 329         memset(&msg, 0, sizeof(msg));
 330
 331         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 332                 return -EINVAL;
 333
 334         msg.msg_control = (caddr_t)tmp;
 335         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 336
 337         cmptr = CMSG_FIRSTHDR(&msg);
 338         cmptr->cmsg_level = SOL_SOCKET;
 339         cmptr->cmsg_type = SCM_RIGHTS;
 340         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 341         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 342         /* Sum of the length of all control messages in the buffer: */
 343         msg.msg_controllen = cmptr->cmsg_len;
 344
 345         iov[0].iov_base = &dummy;
 346         iov[0].iov_len = 1;
 347         msg.msg_iov = iov;
 348         msg.msg_iovlen = 1;
 349
 350         ret = sendmsg(sock, &msg, 0);
 351         if (ret < 0) {
 352                 perror("sendmsg");
 353         }
 354         return ret;
 355 }
 356
 357 /*
 358  * Recv a message accompanied by fd(s) from a unix socket.
 359  *
 360  * Returns the size of received data, or negative error value.
 361  *
 362  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 363  * actually received in nb_fd.
 364  */
 365 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 366 {
 367         struct iovec iov[1];
 368         ssize_t ret = 0;
 369         struct cmsghdr *cmsg;
 370         size_t sizeof_fds = nb_fd * sizeof(int);
 371         char recv_fd[CMSG_SPACE(sizeof_fds)];
 372         struct msghdr msg;
 373         char dummy;
 374
 375         memset(&msg, 0, sizeof(msg));
 376
 377         /* Prepare to receive the structures */
 378         iov[0].iov_base = &dummy;
 379         iov[0].iov_len = 1;
 380         msg.msg_iov = iov;
 381         msg.msg_iovlen = 1;
 382         msg.msg_control = recv_fd;
 383         msg.msg_controllen = sizeof(recv_fd);
 384
 385         ret = recvmsg(sock, &msg, 0);
 386         if (ret < 0) {
 387                 perror("recvmsg fds");
 388                 goto end;
 389         }
 390         if (ret != 1) {
 391                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 392                                 ret, 1);
 393                 goto end;
 394         }
 395         if (msg.msg_flags & MSG_CTRUNC) {
 396                 fprintf(stderr, "Error: Control message truncated.\n");
 397                 ret = -1;
 398                 goto end;
 399         }
 400         cmsg = CMSG_FIRSTHDR(&msg);
 401         if (!cmsg) {
 402                 fprintf(stderr, "Error: Invalid control message header\n");
 403                 ret = -1;
 404                 goto end;
 405         }
 406         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 407                 fprintf(stderr, "Didn't received any fd\n");
 408                 ret = -1;
 409                 goto end;
 410         }
 411         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 412                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 413                                 cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
 414                 ret = -1;
 415                 goto end;
 416         }
 417         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 418         ret = sizeof_fds;
 419 end:
 420         return ret;
 421 }
 422
 423 /*
 424  * Send a message with credentials over a unix socket.
 425  *
 426  * Returns the size of data sent, or negative error value.
 427  */
 428 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 429 {
 430         struct msghdr msg;
 431         struct cmsghdr *cmptr;
 432         struct iovec iov[1];
 433         ssize_t ret = -1;
 434         struct ucred *creds;
 435         size_t sizeof_cred = sizeof(struct ucred);
 436         char anc_buf[CMSG_SPACE(sizeof_cred)];
 437
 438         memset(&msg, 0, sizeof(msg));
 439
 440         iov[0].iov_base = buf;
 441         iov[0].iov_len = len;
 442         msg.msg_iov = iov;
 443         msg.msg_iovlen = 1;
 444
 445         msg.msg_control = (caddr_t) anc_buf;
 446         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 447
 448         cmptr = CMSG_FIRSTHDR(&msg);
 449         cmptr->cmsg_level = SOL_SOCKET;
 450         cmptr->cmsg_type = SCM_CREDENTIALS;
 451         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 452
 453         creds = (struct ucred *) CMSG_DATA(cmptr);
 454
 455         creds->uid = geteuid();
 456         creds->gid = getegid();
 457         creds->pid = getpid();
 458
 459         ret = sendmsg(sock, &msg, 0);
 460         if (ret < 0) {
 461                 perror("sendmsg");
 462         }
 463
 464         return ret;
 465 }
 466
 467 /*
 468  * Recv a message accompanied with credentials from a unix socket.
 469  *
 470  * Returns the size of received data, or negative error value.
 471  */
 472 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 473                 struct ucred *creds)
 474 {
 475         struct msghdr msg;
 476         struct cmsghdr *cmptr;
 477         struct iovec iov[1];
 478         ssize_t ret;
 479         size_t sizeof_cred = sizeof(struct ucred);
 480         char anc_buf[CMSG_SPACE(sizeof_cred)];
 481
 482         memset(&msg, 0, sizeof(msg));
 483
 484         /* Not allowed */
 485         if (creds == NULL) {
 486                 ret = -1;
 487                 goto end;
 488         }
 489
 490         /* Prepare to receive the structures */
 491         iov[0].iov_base = buf;
 492         iov[0].iov_len = len;
 493         msg.msg_iov = iov;
 494         msg.msg_iovlen = 1;
 495
 496         msg.msg_control = anc_buf;
 497         msg.msg_controllen = sizeof(anc_buf);
 498
 499         ret = recvmsg(sock, &msg, 0);
 500         if (ret < 0) {
 501                 perror("recvmsg fds");
 502                 goto end;
 503         }
 504
 505         if (msg.msg_flags & MSG_CTRUNC) {
 506                 fprintf(stderr, "Error: Control message truncated.\n");
 507                 ret = -1;
 508                 goto end;
 509         }
 510
 511         cmptr = CMSG_FIRSTHDR(&msg);
 512         if (cmptr == NULL) {
 513                 fprintf(stderr, "Error: Invalid control message header\n");
 514                 ret = -1;
 515                 goto end;
 516         }
 517
 518         if (cmptr->cmsg_level != SOL_SOCKET ||
 519                         cmptr->cmsg_type != SCM_CREDENTIALS) {
 520                 fprintf(stderr, "Didn't received any credentials\n");
 521                 ret = -1;
 522                 goto end;
 523         }
 524
 525         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 526                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 527                                 cmptr->cmsg_len, CMSG_LEN(sizeof_cred));
 528                 ret = -1;
 529                 goto end;
 530         }
 531
 532         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 533
 534 end:
 535         return ret;
 536 }
 537
 538 /*
 539  * Set socket option to use credentials passing.
 540  */
 541 int lttcomm_setsockopt_creds_unix_sock(int sock)
 542 {
 543         int ret, on = 1;
 544
 545         /* Set socket for credentials retrieval */
 546         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 547         if (ret < 0) {
 548                 perror("setsockopt creds unix sock");
 549         }
 550
 551         return ret;
 552 }