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 <unistd.h>
  28 #include <errno.h>
  29
  30 #include <common/defaults.h>
  31 #include <common/error.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, ret, closeret;
 145
 146         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 147         if (fd < 0) {
 148                 PERROR("socket");
 149                 ret = fd;
 150                 goto error;
 151         }
 152
 153         memset(&sun, 0, sizeof(sun));
 154         sun.sun_family = AF_UNIX;
 155         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 156         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 157
 158         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 159         if (ret < 0) {
 160                 /*
 161                  * Don't print message on connect error, because connect is used in
 162                  * normal execution to detect if sessiond is alive.
 163                  */
 164                 goto error_connect;
 165         }
 166
 167         return fd;
 168
 169 error_connect:
 170         closeret = close(fd);
 171         if (closeret) {
 172                 PERROR("close");
 173         }
 174 error:
 175         return ret;
 176 }
 177
 178 /*
 179  * Do an accept(2) on the sock and return the new file descriptor. The socket
 180  * MUST be bind(2) before.
 181  */
 182 int lttcomm_accept_unix_sock(int sock)
 183 {
 184         int new_fd;
 185         struct sockaddr_un sun;
 186         socklen_t len = 0;
 187
 188         /* Blocking call */
 189         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 190         if (new_fd < 0) {
 191                 PERROR("accept");
 192         }
 193
 194         return new_fd;
 195 }
 196
 197 /*
 198  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 199  * and return the fd.
 200  */
 201 int lttcomm_create_unix_sock(const char *pathname)
 202 {
 203         struct sockaddr_un sun;
 204         int fd;
 205         int ret = -1;
 206
 207         /* Create server socket */
 208         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 209                 PERROR("socket");
 210                 goto error;
 211         }
 212
 213         memset(&sun, 0, sizeof(sun));
 214         sun.sun_family = AF_UNIX;
 215         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 216         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 217
 218         /* Unlink the old file if present */
 219         (void) unlink(pathname);
 220         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 221         if (ret < 0) {
 222                 PERROR("bind");
 223                 goto error;
 224         }
 225
 226         return fd;
 227
 228 error:
 229         return ret;
 230 }
 231
 232 /*
 233  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 234  */
 235 int lttcomm_listen_unix_sock(int sock)
 236 {
 237         int ret;
 238
 239         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 240         if (ret < 0) {
 241                 PERROR("listen");
 242         }
 243
 244         return ret;
 245 }
 246
 247 /*
 248  * Receive data of size len in put that data into the buf param. Using recvmsg
 249  * API.
 250  *
 251  * Return the size of received data.
 252  */
 253 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 254 {
 255         struct msghdr msg;
 256         struct iovec iov[1];
 257         ssize_t ret = -1;
 258
 259         memset(&msg, 0, sizeof(msg));
 260
 261         iov[0].iov_base = buf;
 262         iov[0].iov_len = len;
 263         msg.msg_iov = iov;
 264         msg.msg_iovlen = 1;
 265
 266         ret = recvmsg(sock, &msg, MSG_WAITALL);
 267         if (ret < 0) {
 268                 PERROR("recvmsg");
 269         }
 270
 271         return ret;
 272 }
 273
 274 /*
 275  * Send buf data of size len. Using sendmsg API.
 276  *
 277  * Return the size of sent data.
 278  */
 279 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 280 {
 281         struct msghdr msg;
 282         struct iovec iov[1];
 283         ssize_t ret = -1;
 284
 285         memset(&msg, 0, sizeof(msg));
 286
 287         iov[0].iov_base = buf;
 288         iov[0].iov_len = len;
 289         msg.msg_iov = iov;
 290         msg.msg_iovlen = 1;
 291
 292         ret = sendmsg(sock, &msg, 0);
 293         if (ret < 0) {
 294                 PERROR("sendmsg");
 295         }
 296
 297         return ret;
 298 }
 299
 300 /*
 301  * Shutdown cleanly a unix socket.
 302  */
 303 int lttcomm_close_unix_sock(int sock)
 304 {
 305         int ret, closeret;
 306
 307         /* Shutdown receptions and transmissions */
 308         ret = shutdown(sock, SHUT_RDWR);
 309         if (ret < 0) {
 310                 PERROR("shutdown");
 311         }
 312
 313         closeret = close(sock);
 314         if (closeret) {
 315                 PERROR("close");
 316         }
 317
 318         return ret;
 319 }
 320
 321 /*
 322  * Send a message accompanied by fd(s) over a unix socket.
 323  *
 324  * Returns the size of data sent, or negative error value.
 325  */
 326 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 327 {
 328         struct msghdr msg;
 329         struct cmsghdr *cmptr;
 330         struct iovec iov[1];
 331         ssize_t ret = -1;
 332         unsigned int sizeof_fds = nb_fd * sizeof(int);
 333         char tmp[CMSG_SPACE(sizeof_fds)];
 334         char dummy = 0;
 335
 336         memset(&msg, 0, sizeof(msg));
 337
 338         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 339                 return -EINVAL;
 340
 341         msg.msg_control = (caddr_t)tmp;
 342         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 343
 344         cmptr = CMSG_FIRSTHDR(&msg);
 345         cmptr->cmsg_level = SOL_SOCKET;
 346         cmptr->cmsg_type = SCM_RIGHTS;
 347         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 348         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 349         /* Sum of the length of all control messages in the buffer: */
 350         msg.msg_controllen = cmptr->cmsg_len;
 351
 352         iov[0].iov_base = &dummy;
 353         iov[0].iov_len = 1;
 354         msg.msg_iov = iov;
 355         msg.msg_iovlen = 1;
 356
 357         ret = sendmsg(sock, &msg, 0);
 358         if (ret < 0) {
 359                 PERROR("sendmsg");
 360         }
 361         return ret;
 362 }
 363
 364 /*
 365  * Recv a message accompanied by fd(s) from a unix socket.
 366  *
 367  * Returns the size of received data, or negative error value.
 368  *
 369  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 370  * actually received in nb_fd.
 371  */
 372 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 373 {
 374         struct iovec iov[1];
 375         ssize_t ret = 0;
 376         struct cmsghdr *cmsg;
 377         size_t sizeof_fds = nb_fd * sizeof(int);
 378         char recv_fd[CMSG_SPACE(sizeof_fds)];
 379         struct msghdr msg;
 380         char dummy;
 381
 382         memset(&msg, 0, sizeof(msg));
 383
 384         /* Prepare to receive the structures */
 385         iov[0].iov_base = &dummy;
 386         iov[0].iov_len = 1;
 387         msg.msg_iov = iov;
 388         msg.msg_iovlen = 1;
 389         msg.msg_control = recv_fd;
 390         msg.msg_controllen = sizeof(recv_fd);
 391
 392         ret = recvmsg(sock, &msg, 0);
 393         if (ret < 0) {
 394                 PERROR("recvmsg fds");
 395                 goto end;
 396         }
 397         if (ret != 1) {
 398                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 399                                 ret, 1);
 400                 goto end;
 401         }
 402         if (msg.msg_flags & MSG_CTRUNC) {
 403                 fprintf(stderr, "Error: Control message truncated.\n");
 404                 ret = -1;
 405                 goto end;
 406         }
 407         cmsg = CMSG_FIRSTHDR(&msg);
 408         if (!cmsg) {
 409                 fprintf(stderr, "Error: Invalid control message header\n");
 410                 ret = -1;
 411                 goto end;
 412         }
 413         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 414                 fprintf(stderr, "Didn't received any fd\n");
 415                 ret = -1;
 416                 goto end;
 417         }
 418         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 419                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 420                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 421                 ret = -1;
 422                 goto end;
 423         }
 424         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 425         ret = sizeof_fds;
 426 end:
 427         return ret;
 428 }
 429
 430 /*
 431  * Send a message with credentials over a unix socket.
 432  *
 433  * Returns the size of data sent, or negative error value.
 434  */
 435 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 436 {
 437         struct msghdr msg;
 438         struct iovec iov[1];
 439         ssize_t ret = -1;
 440 #ifdef __linux__
 441         struct cmsghdr *cmptr;
 442         size_t sizeof_cred = sizeof(lttng_sock_cred);
 443         char anc_buf[CMSG_SPACE(sizeof_cred)];
 444         lttng_sock_cred *creds;
 445 #endif /* __linux__ */
 446
 447         memset(&msg, 0, sizeof(msg));
 448
 449         iov[0].iov_base = buf;
 450         iov[0].iov_len = len;
 451         msg.msg_iov = iov;
 452         msg.msg_iovlen = 1;
 453
 454 #ifdef __linux__
 455         msg.msg_control = (caddr_t) anc_buf;
 456         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 457
 458         cmptr = CMSG_FIRSTHDR(&msg);
 459         cmptr->cmsg_level = SOL_SOCKET;
 460         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 461         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 462
 463         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 464
 465         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 466         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 467         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 468 #endif /* __linux__ */
 469
 470         ret = sendmsg(sock, &msg, 0);
 471         if (ret < 0) {
 472                 PERROR("sendmsg");
 473         }
 474
 475         return ret;
 476 }
 477
 478 /*
 479  * Recv a message accompanied with credentials from a unix socket.
 480  *
 481  * Returns the size of received data, or negative error value.
 482  */
 483 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 484                 lttng_sock_cred *creds)
 485 {
 486         struct msghdr msg;
 487         struct iovec iov[1];
 488         ssize_t ret;
 489 #ifdef __linux__
 490         struct cmsghdr *cmptr;
 491         size_t sizeof_cred = sizeof(lttng_sock_cred);
 492         char anc_buf[CMSG_SPACE(sizeof_cred)];
 493 #endif  /* __linux__ */
 494
 495         memset(&msg, 0, sizeof(msg));
 496
 497         /* Not allowed */
 498         if (creds == NULL) {
 499                 ret = -1;
 500                 goto end;
 501         }
 502
 503         /* Prepare to receive the structures */
 504         iov[0].iov_base = buf;
 505         iov[0].iov_len = len;
 506         msg.msg_iov = iov;
 507         msg.msg_iovlen = 1;
 508
 509 #ifdef __linux__
 510         msg.msg_control = anc_buf;
 511         msg.msg_controllen = sizeof(anc_buf);
 512 #endif /* __linux__ */
 513
 514         ret = recvmsg(sock, &msg, 0);
 515         if (ret < 0) {
 516                 PERROR("recvmsg fds");
 517                 goto end;
 518         }
 519
 520 #ifdef __linux__
 521         if (msg.msg_flags & MSG_CTRUNC) {
 522                 fprintf(stderr, "Error: Control message truncated.\n");
 523                 ret = -1;
 524                 goto end;
 525         }
 526
 527         cmptr = CMSG_FIRSTHDR(&msg);
 528         if (cmptr == NULL) {
 529                 fprintf(stderr, "Error: Invalid control message header\n");
 530                 ret = -1;
 531                 goto end;
 532         }
 533
 534         if (cmptr->cmsg_level != SOL_SOCKET ||
 535                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 536                 fprintf(stderr, "Didn't received any credentials\n");
 537                 ret = -1;
 538                 goto end;
 539         }
 540
 541         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 542                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 543                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 544                 ret = -1;
 545                 goto end;
 546         }
 547
 548         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 549 #elif defined(__FreeBSD__)
 550         {
 551                 int peer_ret;
 552
 553                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 554                 if (peer_ret != 0) {
 555                         return peer_ret;
 556                 }
 557         }
 558 #else
 559 #error "Please implement credential support for your OS."
 560 #endif  /* __linux__ */
 561
 562 end:
 563         return ret;
 564 }
 565
 566 /*
 567  * Set socket option to use credentials passing.
 568  */
 569 #ifdef __linux__
 570 int lttcomm_setsockopt_creds_unix_sock(int sock)
 571 {
 572         int ret, on = 1;
 573
 574         /* Set socket for credentials retrieval */
 575         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 576         if (ret < 0) {
 577                 PERROR("setsockopt creds unix sock");
 578         }
 579         return ret;
 580 }
 581 #elif defined(__FreeBSD__)
 582 int lttcomm_setsockopt_creds_unix_sock(int sock)
 583 {
 584         return 0;
 585 }
 586 #else
 587 #error "Please implement credential support for your OS."
 588 #endif /* __linux__ */