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 #include <common/error.h>
  33
  34 #include "sessiond-comm.h"
  35
  36 /*
  37  * Human readable error message.
  38  */
  39 static const char *lttcomm_readable_code[] = {
  40         [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
  41         [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
  42         [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
  43         [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
  44         [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
  45         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
  46         [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
  47         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
  48         [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
  49         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
  50         [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
  51         [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_DIR_FAIL) ] = "Create directory failed",
  52         [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
  53         [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
  54         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
  55         [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
  56         [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
  57         [ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
  58         [ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
  59         [ LTTCOMM_ERR_INDEX(LTTCOMM_EPERM) ] = "Permission denied",
  60         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_VERSION) ] = "Kernel tracer version is not compatible",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  73         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  74         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  75         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  76         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  77         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  78         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  79         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  80         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CALIBRATE_FAIL) ] = "UST calibration failed",
  81         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_VERSION) ] = "UST tracer version is not compatible",
  82         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
  83         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
  84         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
  85         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
  86         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
  87         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
  88         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
  89         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
  90         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
  91         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
  92         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
  93         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
  94         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
  95         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
  96         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
  97         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
  98         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
  99         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
 100         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
 101         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
 102         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
 103         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
 104         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_INVAL)] = "UST invalid context",
 105         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
 106         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
 107         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
 108         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
 109         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 110         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 111         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 112         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 113         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 114         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 115         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 116         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 117         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 118         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 119         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 120         [ LTTCOMM_ERR_INDEX(LTTCOMM_NEED_ROOT_SESSIOND) ] = "A root lttng-sessiond needs to be running, and client user part of the \"tracing\" group, to interact with kernel tracing",
 121 };
 122
 123 /*
 124  * Return ptr to string representing a human readable error code from the
 125  * lttcomm_return_code enum.
 126  *
 127  * These code MUST be negative in other to treat that as an error value.
 128  */
 129 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 130 {
 131         int tmp_code = -code;
 132
 133         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 134                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 135         }
 136
 137         return "Unknown error code";
 138 }
 139
 140 /*
 141  * Connect to unix socket using the path name.
 142  */
 143 int lttcomm_connect_unix_sock(const char *pathname)
 144 {
 145         struct sockaddr_un sun;
 146         int fd, ret, closeret;
 147
 148         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 149         if (fd < 0) {
 150                 PERROR("socket");
 151                 ret = fd;
 152                 goto error;
 153         }
 154
 155         memset(&sun, 0, sizeof(sun));
 156         sun.sun_family = AF_UNIX;
 157         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 158         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 159
 160         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 161         if (ret < 0) {
 162                 /*
 163                  * Don't print message on connect error, because connect is used in
 164                  * normal execution to detect if sessiond is alive.
 165                  */
 166                 goto error_connect;
 167         }
 168
 169         return fd;
 170
 171 error_connect:
 172         closeret = close(fd);
 173         if (closeret) {
 174                 PERROR("close");
 175         }
 176 error:
 177         return ret;
 178 }
 179
 180 /*
 181  * Do an accept(2) on the sock and return the new file descriptor. The socket
 182  * MUST be bind(2) before.
 183  */
 184 int lttcomm_accept_unix_sock(int sock)
 185 {
 186         int new_fd;
 187         struct sockaddr_un sun;
 188         socklen_t len = 0;
 189
 190         /* Blocking call */
 191         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 192         if (new_fd < 0) {
 193                 PERROR("accept");
 194         }
 195
 196         return new_fd;
 197 }
 198
 199 /*
 200  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 201  * and return the fd.
 202  */
 203 int lttcomm_create_unix_sock(const char *pathname)
 204 {
 205         struct sockaddr_un sun;
 206         int fd;
 207         int ret = -1;
 208
 209         /* Create server socket */
 210         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 211                 PERROR("socket");
 212                 goto error;
 213         }
 214
 215         memset(&sun, 0, sizeof(sun));
 216         sun.sun_family = AF_UNIX;
 217         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 218         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 219
 220         /* Unlink the old file if present */
 221         (void) unlink(pathname);
 222         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 223         if (ret < 0) {
 224                 PERROR("bind");
 225                 goto error;
 226         }
 227
 228         return fd;
 229
 230 error:
 231         return ret;
 232 }
 233
 234 /*
 235  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 236  */
 237 int lttcomm_listen_unix_sock(int sock)
 238 {
 239         int ret;
 240
 241         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 242         if (ret < 0) {
 243                 PERROR("listen");
 244         }
 245
 246         return ret;
 247 }
 248
 249 /*
 250  * Receive data of size len in put that data into the buf param. Using recvmsg
 251  * API.
 252  *
 253  * Return the size of received data.
 254  */
 255 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 256 {
 257         struct msghdr msg;
 258         struct iovec iov[1];
 259         ssize_t ret = -1;
 260
 261         memset(&msg, 0, sizeof(msg));
 262
 263         iov[0].iov_base = buf;
 264         iov[0].iov_len = len;
 265         msg.msg_iov = iov;
 266         msg.msg_iovlen = 1;
 267
 268         ret = recvmsg(sock, &msg, MSG_WAITALL);
 269         if (ret < 0) {
 270                 PERROR("recvmsg");
 271         }
 272
 273         return ret;
 274 }
 275
 276 /*
 277  * Send buf data of size len. Using sendmsg API.
 278  *
 279  * Return the size of sent data.
 280  */
 281 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 282 {
 283         struct msghdr msg;
 284         struct iovec iov[1];
 285         ssize_t ret = -1;
 286
 287         memset(&msg, 0, sizeof(msg));
 288
 289         iov[0].iov_base = buf;
 290         iov[0].iov_len = len;
 291         msg.msg_iov = iov;
 292         msg.msg_iovlen = 1;
 293
 294         ret = sendmsg(sock, &msg, 0);
 295         if (ret < 0) {
 296                 /*
 297                  * Only warn about EPIPE when quiet mode is deactivated.
 298                  * We consider EPIPE as expected.
 299                  */
 300                 if (errno != EPIPE || !opt_quiet) {
 301                         PERROR("sendmsg");
 302                 }
 303         }
 304
 305         return ret;
 306 }
 307
 308 /*
 309  * Shutdown cleanly a unix socket.
 310  */
 311 int lttcomm_close_unix_sock(int sock)
 312 {
 313         int ret, closeret;
 314
 315         /* Shutdown receptions and transmissions */
 316         ret = shutdown(sock, SHUT_RDWR);
 317         if (ret < 0) {
 318                 PERROR("shutdown");
 319         }
 320
 321         closeret = close(sock);
 322         if (closeret) {
 323                 PERROR("close");
 324         }
 325
 326         return ret;
 327 }
 328
 329 /*
 330  * Send a message accompanied by fd(s) over a unix socket.
 331  *
 332  * Returns the size of data sent, or negative error value.
 333  */
 334 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 335 {
 336         struct msghdr msg;
 337         struct cmsghdr *cmptr;
 338         struct iovec iov[1];
 339         ssize_t ret = -1;
 340         unsigned int sizeof_fds = nb_fd * sizeof(int);
 341         char tmp[CMSG_SPACE(sizeof_fds)];
 342         char dummy = 0;
 343
 344         memset(&msg, 0, sizeof(msg));
 345
 346         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 347                 return -EINVAL;
 348
 349         msg.msg_control = (caddr_t)tmp;
 350         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 351
 352         cmptr = CMSG_FIRSTHDR(&msg);
 353         cmptr->cmsg_level = SOL_SOCKET;
 354         cmptr->cmsg_type = SCM_RIGHTS;
 355         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 356         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 357         /* Sum of the length of all control messages in the buffer: */
 358         msg.msg_controllen = cmptr->cmsg_len;
 359
 360         iov[0].iov_base = &dummy;
 361         iov[0].iov_len = 1;
 362         msg.msg_iov = iov;
 363         msg.msg_iovlen = 1;
 364
 365         ret = sendmsg(sock, &msg, 0);
 366         if (ret < 0) {
 367                 /*
 368                  * Only warn about EPIPE when quiet mode is deactivated.
 369                  * We consider EPIPE as expected.
 370                  */
 371                 if (errno != EPIPE || !opt_quiet) {
 372                         PERROR("sendmsg");
 373                 }
 374         }
 375         return ret;
 376 }
 377
 378 /*
 379  * Recv a message accompanied by fd(s) from a unix socket.
 380  *
 381  * Returns the size of received data, or negative error value.
 382  *
 383  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 384  * actually received in nb_fd.
 385  */
 386 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 387 {
 388         struct iovec iov[1];
 389         ssize_t ret = 0;
 390         struct cmsghdr *cmsg;
 391         size_t sizeof_fds = nb_fd * sizeof(int);
 392         char recv_fd[CMSG_SPACE(sizeof_fds)];
 393         struct msghdr msg;
 394         char dummy;
 395
 396         memset(&msg, 0, sizeof(msg));
 397
 398         /* Prepare to receive the structures */
 399         iov[0].iov_base = &dummy;
 400         iov[0].iov_len = 1;
 401         msg.msg_iov = iov;
 402         msg.msg_iovlen = 1;
 403         msg.msg_control = recv_fd;
 404         msg.msg_controllen = sizeof(recv_fd);
 405
 406         ret = recvmsg(sock, &msg, 0);
 407         if (ret < 0) {
 408                 PERROR("recvmsg fds");
 409                 goto end;
 410         }
 411         if (ret != 1) {
 412                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 413                                 ret, 1);
 414                 goto end;
 415         }
 416         if (msg.msg_flags & MSG_CTRUNC) {
 417                 fprintf(stderr, "Error: Control message truncated.\n");
 418                 ret = -1;
 419                 goto end;
 420         }
 421         cmsg = CMSG_FIRSTHDR(&msg);
 422         if (!cmsg) {
 423                 fprintf(stderr, "Error: Invalid control message header\n");
 424                 ret = -1;
 425                 goto end;
 426         }
 427         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 428                 fprintf(stderr, "Didn't received any fd\n");
 429                 ret = -1;
 430                 goto end;
 431         }
 432         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 433                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 434                                 cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
 435                 ret = -1;
 436                 goto end;
 437         }
 438         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 439         ret = sizeof_fds;
 440 end:
 441         return ret;
 442 }
 443
 444 /*
 445  * Send a message with credentials over a unix socket.
 446  *
 447  * Returns the size of data sent, or negative error value.
 448  */
 449 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 450 {
 451         struct msghdr msg;
 452         struct cmsghdr *cmptr;
 453         struct iovec iov[1];
 454         ssize_t ret = -1;
 455         struct ucred *creds;
 456         size_t sizeof_cred = sizeof(struct ucred);
 457         char anc_buf[CMSG_SPACE(sizeof_cred)];
 458
 459         memset(&msg, 0, sizeof(msg));
 460
 461         iov[0].iov_base = buf;
 462         iov[0].iov_len = len;
 463         msg.msg_iov = iov;
 464         msg.msg_iovlen = 1;
 465
 466         msg.msg_control = (caddr_t) anc_buf;
 467         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 468
 469         cmptr = CMSG_FIRSTHDR(&msg);
 470         cmptr->cmsg_level = SOL_SOCKET;
 471         cmptr->cmsg_type = SCM_CREDENTIALS;
 472         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 473
 474         creds = (struct ucred *) CMSG_DATA(cmptr);
 475
 476         creds->uid = geteuid();
 477         creds->gid = getegid();
 478         creds->pid = getpid();
 479
 480         ret = sendmsg(sock, &msg, 0);
 481         if (ret < 0) {
 482                 /*
 483                  * Only warn about EPIPE when quiet mode is deactivated.
 484                  * We consider EPIPE as expected.
 485                  */
 486                 if (errno != EPIPE || !opt_quiet) {
 487                         PERROR("sendmsg");
 488                 }
 489         }
 490         return ret;
 491 }
 492
 493 /*
 494  * Recv a message accompanied with credentials from a unix socket.
 495  *
 496  * Returns the size of received data, or negative error value.
 497  */
 498 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 499                 struct ucred *creds)
 500 {
 501         struct msghdr msg;
 502         struct cmsghdr *cmptr;
 503         struct iovec iov[1];
 504         ssize_t ret;
 505         size_t sizeof_cred = sizeof(struct ucred);
 506         char anc_buf[CMSG_SPACE(sizeof_cred)];
 507
 508         memset(&msg, 0, sizeof(msg));
 509
 510         /* Not allowed */
 511         if (creds == NULL) {
 512                 ret = -1;
 513                 goto end;
 514         }
 515
 516         /* Prepare to receive the structures */
 517         iov[0].iov_base = buf;
 518         iov[0].iov_len = len;
 519         msg.msg_iov = iov;
 520         msg.msg_iovlen = 1;
 521
 522         msg.msg_control = anc_buf;
 523         msg.msg_controllen = sizeof(anc_buf);
 524
 525         ret = recvmsg(sock, &msg, 0);
 526         if (ret < 0) {
 527                 PERROR("recvmsg fds");
 528                 goto end;
 529         }
 530
 531         if (msg.msg_flags & MSG_CTRUNC) {
 532                 fprintf(stderr, "Error: Control message truncated.\n");
 533                 ret = -1;
 534                 goto end;
 535         }
 536
 537         cmptr = CMSG_FIRSTHDR(&msg);
 538         if (cmptr == NULL) {
 539                 fprintf(stderr, "Error: Invalid control message header\n");
 540                 ret = -1;
 541                 goto end;
 542         }
 543
 544         if (cmptr->cmsg_level != SOL_SOCKET ||
 545                         cmptr->cmsg_type != SCM_CREDENTIALS) {
 546                 fprintf(stderr, "Didn't received any credentials\n");
 547                 ret = -1;
 548                 goto end;
 549         }
 550
 551         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 552                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 553                                 cmptr->cmsg_len, CMSG_LEN(sizeof_cred));
 554                 ret = -1;
 555                 goto end;
 556         }
 557
 558         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 559
 560 end:
 561         return ret;
 562 }
 563
 564 /*
 565  * Set socket option to use credentials passing.
 566  */
 567 int lttcomm_setsockopt_creds_unix_sock(int sock)
 568 {
 569         int ret, on = 1;
 570
 571         /* Set socket for credentials retrieval */
 572         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 573         if (ret < 0) {
 574                 PERROR("setsockopt creds unix sock");
 575         }
 576
 577         return ret;
 578 }