src/common/unix.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
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   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
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _LGPL_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/common.h>
  31 #include <common/sessiond-comm/sessiond-comm.h>
  32
  33 #include "unix.h"
  34
  35 /*
  36  * Connect to unix socket using the path name.
  37  */
  38 LTTNG_HIDDEN
  39 int lttcomm_connect_unix_sock(const char *pathname)
  40 {
  41         struct sockaddr_un s_un;
  42         int fd, ret, closeret;
  43
  44         if (strlen(pathname) >= sizeof(s_un.sun_path)) {
  45                 ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
  46                                 pathname, strlen(pathname) + 1,
  47                                 sizeof(s_un.sun_path));
  48                 ret = -ENAMETOOLONG;
  49                 goto error;
  50         }
  51
  52         fd = socket(PF_UNIX, SOCK_STREAM, 0);
  53         if (fd < 0) {
  54                 PERROR("socket");
  55                 ret = fd;
  56                 goto error;
  57         }
  58
  59         memset(&s_un, 0, sizeof(s_un));
  60         s_un.sun_family = AF_UNIX;
  61         strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path));
  62         s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0';
  63
  64         ret = connect(fd, (struct sockaddr *) &s_un, sizeof(s_un));
  65         if (ret < 0) {
  66                 /*
  67                  * Don't print message on connect error, because connect is used in
  68                  * normal execution to detect if sessiond is alive.
  69                  */
  70                 goto error_connect;
  71         }
  72
  73         return fd;
  74
  75 error_connect:
  76         closeret = close(fd);
  77         if (closeret) {
  78                 PERROR("close");
  79         }
  80 error:
  81         return ret;
  82 }
  83
  84 /*
  85  * Do an accept(2) on the sock and return the new file descriptor. The socket
  86  * MUST be bind(2) before.
  87  */
  88 LTTNG_HIDDEN
  89 int lttcomm_accept_unix_sock(int sock)
  90 {
  91         int new_fd;
  92         struct sockaddr_un s_un;
  93         socklen_t len = sizeof(s_un);
  94
  95         /* Blocking call */
  96         new_fd = accept(sock, (struct sockaddr *) &s_un, &len);
  97         if (new_fd < 0) {
  98                 PERROR("accept");
  99         }
 100
 101         return new_fd;
 102 }
 103
 104 LTTNG_HIDDEN
 105 int lttcomm_create_anon_unix_socketpair(int *fds)
 106 {
 107         if (socketpair(PF_UNIX, SOCK_STREAM, 0, fds) < 0) {
 108                 PERROR("socketpair");
 109                 return -1;
 110         }
 111         return 0;
 112 }
 113
 114 /*
 115  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 116  * and return the fd.
 117  */
 118 LTTNG_HIDDEN
 119 int lttcomm_create_unix_sock(const char *pathname)
 120 {
 121         struct sockaddr_un s_un;
 122         int fd = -1;
 123         int ret = -1;
 124
 125         if (strlen(pathname) >= sizeof(s_un.sun_path)) {
 126                 ERR("unix socket address (\"%s\") is longer than the platform's limit (%zu > %zu).",
 127                                 pathname, strlen(pathname) + 1,
 128                                 sizeof(s_un.sun_path));
 129                 ret = -ENAMETOOLONG;
 130                 goto error;
 131         }
 132
 133         /* Create server socket */
 134         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 135                 PERROR("socket");
 136                 goto error;
 137         }
 138
 139         memset(&s_un, 0, sizeof(s_un));
 140         s_un.sun_family = AF_UNIX;
 141         strncpy(s_un.sun_path, pathname, sizeof(s_un.sun_path));
 142         s_un.sun_path[sizeof(s_un.sun_path) - 1] = '\0';
 143
 144         /* Unlink the old file if present */
 145         (void) unlink(pathname);
 146         ret = bind(fd, (struct sockaddr *) &s_un, sizeof(s_un));
 147         if (ret < 0) {
 148                 PERROR("bind");
 149                 goto error;
 150         }
 151
 152         return fd;
 153
 154 error:
 155         if (fd >= 0) {
 156                 if (close(fd) < 0) {
 157                         PERROR("close create unix sock");
 158                 }
 159         }
 160         return ret;
 161 }
 162
 163 /*
 164  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 165  */
 166 LTTNG_HIDDEN
 167 int lttcomm_listen_unix_sock(int sock)
 168 {
 169         int ret;
 170
 171         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 172         if (ret < 0) {
 173                 PERROR("listen");
 174         }
 175
 176         return ret;
 177 }
 178
 179 /*
 180  * Receive data of size len in put that data into the buf param. Using recvmsg
 181  * API.
 182  *
 183  * Return the size of received data.
 184  */
 185 LTTNG_HIDDEN
 186 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 187 {
 188         struct msghdr msg;
 189         struct iovec iov[1];
 190         ssize_t ret = -1;
 191         size_t len_last;
 192
 193         memset(&msg, 0, sizeof(msg));
 194
 195         iov[0].iov_base = buf;
 196         iov[0].iov_len = len;
 197         msg.msg_iov = iov;
 198         msg.msg_iovlen = 1;
 199
 200         do {
 201                 len_last = iov[0].iov_len;
 202                 ret = lttng_recvmsg_nosigpipe(sock, &msg);
 203                 if (ret > 0) {
 204                         iov[0].iov_base += ret;
 205                         iov[0].iov_len -= ret;
 206                         assert(ret <= len_last);
 207                 }
 208         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 209         if (ret < 0) {
 210                 PERROR("recvmsg");
 211         } else if (ret > 0) {
 212                 ret = len;
 213         }
 214         /* Else ret = 0 meaning an orderly shutdown. */
 215
 216         return ret;
 217 }
 218
 219 /*
 220  * Receive data of size len in put that data into the buf param. Using recvmsg
 221  * API. Only use with sockets set in non-blocking mode.
 222  *
 223  * Return the size of received data.
 224  */
 225 LTTNG_HIDDEN
 226 ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len)
 227 {
 228         struct msghdr msg;
 229         struct iovec iov[1];
 230         ssize_t ret;
 231
 232         memset(&msg, 0, sizeof(msg));
 233
 234         iov[0].iov_base = buf;
 235         iov[0].iov_len = len;
 236         msg.msg_iov = iov;
 237         msg.msg_iovlen = 1;
 238
 239 retry:
 240         ret = lttng_recvmsg_nosigpipe(sock, &msg);
 241         if (ret < 0) {
 242                 if (errno == EINTR) {
 243                         goto retry;
 244                 } else {
 245                         /*
 246                          * Only warn about EPIPE when quiet mode is
 247                          * deactivated.
 248                          * We consider EPIPE as expected.
 249                          */
 250                         if (errno != EPIPE || !lttng_opt_quiet) {
 251                                 PERROR("recvmsg");
 252                         }
 253                         goto end;
 254                 }
 255         }
 256         ret = len;
 257 end:
 258         return ret;
 259 }
 260
 261 /*
 262  * Send buf data of size len. Using sendmsg API.
 263  *
 264  * Return the size of sent data.
 265  */
 266 LTTNG_HIDDEN
 267 ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
 268 {
 269         struct msghdr msg;
 270         struct iovec iov[1];
 271         ssize_t ret;
 272
 273         memset(&msg, 0, sizeof(msg));
 274
 275         iov[0].iov_base = (void *) buf;
 276         iov[0].iov_len = len;
 277         msg.msg_iov = iov;
 278         msg.msg_iovlen = 1;
 279
 280         while (iov[0].iov_len) {
 281                 ret = sendmsg(sock, &msg, 0);
 282                 if (ret < 0) {
 283                         if (errno == EINTR) {
 284                                 continue;
 285                         } else {
 286                                 /*
 287                                  * Only warn about EPIPE when quiet mode is
 288                                  * deactivated.
 289                                  * We consider EPIPE as expected.
 290                                  */
 291                                 if (errno != EPIPE || !lttng_opt_quiet) {
 292                                         PERROR("sendmsg");
 293                                 }
 294                                 goto end;
 295                         }
 296                 }
 297                 iov[0].iov_len -= ret;
 298                 iov[0].iov_base += ret;
 299         }
 300         ret = len;
 301 end:
 302         return ret;
 303 }
 304
 305 /*
 306  * Send buf data of size len. Using sendmsg API.
 307  * Only use with non-blocking sockets. The difference with the blocking version
 308  * of the function is that this one does not retry to send on partial sends,
 309  * except if the interruption was caused by a signal (EINTR).
 310  *
 311  * Return the size of sent data.
 312  */
 313 LTTNG_HIDDEN
 314 ssize_t lttcomm_send_unix_sock_non_block(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 retry:
 328         ret = sendmsg(sock, &msg, 0);
 329         if (ret < 0) {
 330                 if (errno == EINTR) {
 331                         goto retry;
 332                 } else {
 333                         /*
 334                          * Only warn about EPIPE when quiet mode is
 335                          * deactivated.
 336                          * We consider EPIPE as expected.
 337                          */
 338                         if (errno != EPIPE || !lttng_opt_quiet) {
 339                                 PERROR("sendmsg");
 340                         }
 341                         goto end;
 342                 }
 343         }
 344         ret = len;
 345 end:
 346         return ret;
 347 }
 348
 349 /*
 350  * Shutdown cleanly a unix socket.
 351  */
 352 LTTNG_HIDDEN
 353 int lttcomm_close_unix_sock(int sock)
 354 {
 355         int ret, closeret;
 356
 357         /* Shutdown receptions and transmissions */
 358         ret = shutdown(sock, SHUT_RDWR);
 359         if (ret < 0) {
 360                 PERROR("shutdown");
 361         }
 362
 363         closeret = close(sock);
 364         if (closeret) {
 365                 PERROR("close");
 366         }
 367
 368         return ret;
 369 }
 370
 371 /*
 372  * Send a message accompanied by fd(s) over a unix socket.
 373  *
 374  * Returns the size of data sent, or negative error value.
 375  */
 376 LTTNG_HIDDEN
 377 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 378 {
 379         struct msghdr msg;
 380         struct cmsghdr *cmptr;
 381         struct iovec iov[1];
 382         ssize_t ret = -1;
 383         unsigned int sizeof_fds = nb_fd * sizeof(int);
 384         char tmp[CMSG_SPACE(sizeof_fds)];
 385         char dummy = 0;
 386
 387         memset(&msg, 0, sizeof(msg));
 388         memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
 389
 390         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 391                 return -EINVAL;
 392
 393         msg.msg_control = (caddr_t)tmp;
 394         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 395
 396         cmptr = CMSG_FIRSTHDR(&msg);
 397         if (!cmptr) {
 398                 return -1;
 399         }
 400         cmptr->cmsg_level = SOL_SOCKET;
 401         cmptr->cmsg_type = SCM_RIGHTS;
 402         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 403         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 404         /* Sum of the length of all control messages in the buffer: */
 405         msg.msg_controllen = cmptr->cmsg_len;
 406
 407         iov[0].iov_base = &dummy;
 408         iov[0].iov_len = 1;
 409         msg.msg_iov = iov;
 410         msg.msg_iovlen = 1;
 411
 412         do {
 413                 ret = sendmsg(sock, &msg, 0);
 414         } while (ret < 0 && errno == EINTR);
 415         if (ret < 0) {
 416                 /*
 417                  * Only warn about EPIPE when quiet mode is deactivated.
 418                  * We consider EPIPE as expected.
 419                  */
 420                 if (errno != EPIPE || !lttng_opt_quiet) {
 421                         PERROR("sendmsg");
 422                 }
 423         }
 424         return ret;
 425 }
 426
 427 /*
 428  * Recv a message accompanied by fd(s) from a unix socket.
 429  *
 430  * Returns the size of received data, or negative error value.
 431  *
 432  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 433  * actually received in nb_fd.
 434  */
 435 LTTNG_HIDDEN
 436 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 437 {
 438         struct iovec iov[1];
 439         ssize_t ret = 0;
 440         struct cmsghdr *cmsg;
 441         size_t sizeof_fds = nb_fd * sizeof(int);
 442         char recv_fd[CMSG_SPACE(sizeof_fds)];
 443         struct msghdr msg;
 444         char dummy;
 445
 446         memset(&msg, 0, sizeof(msg));
 447
 448         /* Prepare to receive the structures */
 449         iov[0].iov_base = &dummy;
 450         iov[0].iov_len = 1;
 451         msg.msg_iov = iov;
 452         msg.msg_iovlen = 1;
 453         msg.msg_control = recv_fd;
 454         msg.msg_controllen = sizeof(recv_fd);
 455
 456         do {
 457                 ret = recvmsg(sock, &msg, 0);
 458         } while (ret < 0 && errno == EINTR);
 459         if (ret < 0) {
 460                 PERROR("recvmsg fds");
 461                 goto end;
 462         }
 463         if (ret != 1) {
 464                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 465                                 ret, 1);
 466                 goto end;
 467         }
 468         if (msg.msg_flags & MSG_CTRUNC) {
 469                 fprintf(stderr, "Error: Control message truncated.\n");
 470                 ret = -1;
 471                 goto end;
 472         }
 473         cmsg = CMSG_FIRSTHDR(&msg);
 474         if (!cmsg) {
 475                 fprintf(stderr, "Error: Invalid control message header\n");
 476                 ret = -1;
 477                 goto end;
 478         }
 479         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 480                 fprintf(stderr, "Didn't received any fd\n");
 481                 ret = -1;
 482                 goto end;
 483         }
 484         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 485                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 486                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 487                 ret = -1;
 488                 goto end;
 489         }
 490         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 491         ret = sizeof_fds;
 492 end:
 493         return ret;
 494 }
 495
 496 /*
 497  * Send a message with credentials over a unix socket.
 498  *
 499  * Returns the size of data sent, or negative error value.
 500  */
 501 LTTNG_HIDDEN
 502 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 503 {
 504         struct msghdr msg;
 505         struct iovec iov[1];
 506         ssize_t ret = -1;
 507 #ifdef __linux__
 508         struct cmsghdr *cmptr;
 509         size_t sizeof_cred = sizeof(lttng_sock_cred);
 510         char anc_buf[CMSG_SPACE(sizeof_cred)];
 511         lttng_sock_cred *creds;
 512
 513         memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
 514 #endif /* __linux__ */
 515
 516         memset(&msg, 0, sizeof(msg));
 517
 518         iov[0].iov_base = buf;
 519         iov[0].iov_len = len;
 520         msg.msg_iov = iov;
 521         msg.msg_iovlen = 1;
 522
 523 #ifdef __linux__
 524         msg.msg_control = (caddr_t) anc_buf;
 525         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 526
 527         cmptr = CMSG_FIRSTHDR(&msg);
 528         if (!cmptr) {
 529                 return -1;
 530         }
 531         cmptr->cmsg_level = SOL_SOCKET;
 532         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 533         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 534
 535         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 536
 537         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 538         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 539         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 540 #endif /* __linux__ */
 541
 542         do {
 543                 ret = sendmsg(sock, &msg, 0);
 544         } while (ret < 0 && errno == EINTR);
 545         if (ret < 0) {
 546                 /*
 547                  * Only warn about EPIPE when quiet mode is deactivated.
 548                  * We consider EPIPE as expected.
 549                  */
 550                 if (errno != EPIPE || !lttng_opt_quiet) {
 551                         PERROR("sendmsg");
 552                 }
 553         }
 554         return ret;
 555 }
 556
 557 /*
 558  * Recv a message accompanied with credentials from a unix socket.
 559  *
 560  * Returns the size of received data, or negative error value.
 561  */
 562 LTTNG_HIDDEN
 563 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 564                 lttng_sock_cred *creds)
 565 {
 566         struct msghdr msg;
 567         struct iovec iov[1];
 568         ssize_t ret;
 569         size_t len_last;
 570 #ifdef __linux__
 571         struct cmsghdr *cmptr;
 572         size_t sizeof_cred = sizeof(lttng_sock_cred);
 573         char anc_buf[CMSG_SPACE(sizeof_cred)];
 574 #endif  /* __linux__ */
 575
 576         memset(&msg, 0, sizeof(msg));
 577
 578         /* Not allowed */
 579         if (creds == NULL) {
 580                 ret = -1;
 581                 goto end;
 582         }
 583
 584         /* Prepare to receive the structures */
 585         iov[0].iov_base = buf;
 586         iov[0].iov_len = len;
 587         msg.msg_iov = iov;
 588         msg.msg_iovlen = 1;
 589
 590 #ifdef __linux__
 591         msg.msg_control = anc_buf;
 592         msg.msg_controllen = sizeof(anc_buf);
 593 #endif /* __linux__ */
 594
 595         do {
 596                 len_last = iov[0].iov_len;
 597                 ret = recvmsg(sock, &msg, 0);
 598                 if (ret > 0) {
 599                         iov[0].iov_base += ret;
 600                         iov[0].iov_len -= ret;
 601                         assert(ret <= len_last);
 602                 }
 603         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 604         if (ret < 0) {
 605                 PERROR("recvmsg fds");
 606                 goto end;
 607         } else if (ret > 0) {
 608                 ret = len;
 609         }
 610         /* Else ret = 0 meaning an orderly shutdown. */
 611
 612 #ifdef __linux__
 613         if (msg.msg_flags & MSG_CTRUNC) {
 614                 fprintf(stderr, "Error: Control message truncated.\n");
 615                 ret = -1;
 616                 goto end;
 617         }
 618
 619         cmptr = CMSG_FIRSTHDR(&msg);
 620         if (cmptr == NULL) {
 621                 fprintf(stderr, "Error: Invalid control message header\n");
 622                 ret = -1;
 623                 goto end;
 624         }
 625
 626         if (cmptr->cmsg_level != SOL_SOCKET ||
 627                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 628                 fprintf(stderr, "Didn't received any credentials\n");
 629                 ret = -1;
 630                 goto end;
 631         }
 632
 633         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 634                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 635                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 636                 ret = -1;
 637                 goto end;
 638         }
 639
 640         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 641 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 642         {
 643                 int peer_ret;
 644
 645                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 646                 if (peer_ret != 0) {
 647                         return peer_ret;
 648                 }
 649         }
 650 #else
 651 #error "Please implement credential support for your OS."
 652 #endif  /* __linux__ */
 653
 654 end:
 655         return ret;
 656 }
 657
 658 /*
 659  * Set socket option to use credentials passing.
 660  */
 661 #ifdef __linux__
 662 LTTNG_HIDDEN
 663 int lttcomm_setsockopt_creds_unix_sock(int sock)
 664 {
 665         int ret, on = 1;
 666
 667         /* Set socket for credentials retrieval */
 668         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 669         if (ret < 0) {
 670                 PERROR("setsockopt creds unix sock");
 671         }
 672         return ret;
 673 }
 674 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 675 LTTNG_HIDDEN
 676 int lttcomm_setsockopt_creds_unix_sock(int sock)
 677 {
 678         return 0;
 679 }
 680 #else
 681 #error "Please implement credential support for your OS."
 682 #endif /* __linux__ */