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  * Send buf data of size len. Using sendmsg API.
 221  *
 222  * Return the size of sent data.
 223  */
 224 LTTNG_HIDDEN
 225 ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
 226 {
 227         struct msghdr msg;
 228         struct iovec iov[1];
 229         ssize_t ret;
 230
 231         memset(&msg, 0, sizeof(msg));
 232
 233         iov[0].iov_base = (void *) buf;
 234         iov[0].iov_len = len;
 235         msg.msg_iov = iov;
 236         msg.msg_iovlen = 1;
 237
 238         while (iov[0].iov_len) {
 239                 ret = sendmsg(sock, &msg, 0);
 240                 if (ret < 0) {
 241                         if (errno == EINTR) {
 242                                 continue;
 243                         } else {
 244                                 /*
 245                                  * Only warn about EPIPE when quiet mode is
 246                                  * deactivated.
 247                                  * We consider EPIPE as expected.
 248                                  */
 249                                 if (errno != EPIPE || !lttng_opt_quiet) {
 250                                         PERROR("sendmsg");
 251                                 }
 252                                 goto end;
 253                         }
 254                 }
 255                 iov[0].iov_len -= ret;
 256                 iov[0].iov_base += ret;
 257         }
 258         ret = len;
 259 end:
 260         return ret;
 261 }
 262
 263 /*
 264  * Shutdown cleanly a unix socket.
 265  */
 266 LTTNG_HIDDEN
 267 int lttcomm_close_unix_sock(int sock)
 268 {
 269         int ret, closeret;
 270
 271         /* Shutdown receptions and transmissions */
 272         ret = shutdown(sock, SHUT_RDWR);
 273         if (ret < 0) {
 274                 PERROR("shutdown");
 275         }
 276
 277         closeret = close(sock);
 278         if (closeret) {
 279                 PERROR("close");
 280         }
 281
 282         return ret;
 283 }
 284
 285 /*
 286  * Send a message accompanied by fd(s) over a unix socket.
 287  *
 288  * Returns the size of data sent, or negative error value.
 289  */
 290 LTTNG_HIDDEN
 291 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 292 {
 293         struct msghdr msg;
 294         struct cmsghdr *cmptr;
 295         struct iovec iov[1];
 296         ssize_t ret = -1;
 297         unsigned int sizeof_fds = nb_fd * sizeof(int);
 298         char tmp[CMSG_SPACE(sizeof_fds)];
 299         char dummy = 0;
 300
 301         memset(&msg, 0, sizeof(msg));
 302         memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
 303
 304         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 305                 return -EINVAL;
 306
 307         msg.msg_control = (caddr_t)tmp;
 308         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 309
 310         cmptr = CMSG_FIRSTHDR(&msg);
 311         if (!cmptr) {
 312                 return -1;
 313         }
 314         cmptr->cmsg_level = SOL_SOCKET;
 315         cmptr->cmsg_type = SCM_RIGHTS;
 316         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 317         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 318         /* Sum of the length of all control messages in the buffer: */
 319         msg.msg_controllen = cmptr->cmsg_len;
 320
 321         iov[0].iov_base = &dummy;
 322         iov[0].iov_len = 1;
 323         msg.msg_iov = iov;
 324         msg.msg_iovlen = 1;
 325
 326         do {
 327                 ret = sendmsg(sock, &msg, 0);
 328         } while (ret < 0 && errno == EINTR);
 329         if (ret < 0) {
 330                 /*
 331                  * Only warn about EPIPE when quiet mode is deactivated.
 332                  * We consider EPIPE as expected.
 333                  */
 334                 if (errno != EPIPE || !lttng_opt_quiet) {
 335                         PERROR("sendmsg");
 336                 }
 337         }
 338         return ret;
 339 }
 340
 341 /*
 342  * Recv a message accompanied by fd(s) from a unix socket.
 343  *
 344  * Returns the size of received data, or negative error value.
 345  *
 346  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 347  * actually received in nb_fd.
 348  */
 349 LTTNG_HIDDEN
 350 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 351 {
 352         struct iovec iov[1];
 353         ssize_t ret = 0;
 354         struct cmsghdr *cmsg;
 355         size_t sizeof_fds = nb_fd * sizeof(int);
 356         char recv_fd[CMSG_SPACE(sizeof_fds)];
 357         struct msghdr msg;
 358         char dummy;
 359
 360         memset(&msg, 0, sizeof(msg));
 361
 362         /* Prepare to receive the structures */
 363         iov[0].iov_base = &dummy;
 364         iov[0].iov_len = 1;
 365         msg.msg_iov = iov;
 366         msg.msg_iovlen = 1;
 367         msg.msg_control = recv_fd;
 368         msg.msg_controllen = sizeof(recv_fd);
 369
 370         do {
 371                 ret = recvmsg(sock, &msg, 0);
 372         } while (ret < 0 && errno == EINTR);
 373         if (ret < 0) {
 374                 PERROR("recvmsg fds");
 375                 goto end;
 376         }
 377         if (ret != 1) {
 378                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 379                                 ret, 1);
 380                 goto end;
 381         }
 382         if (msg.msg_flags & MSG_CTRUNC) {
 383                 fprintf(stderr, "Error: Control message truncated.\n");
 384                 ret = -1;
 385                 goto end;
 386         }
 387         cmsg = CMSG_FIRSTHDR(&msg);
 388         if (!cmsg) {
 389                 fprintf(stderr, "Error: Invalid control message header\n");
 390                 ret = -1;
 391                 goto end;
 392         }
 393         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 394                 fprintf(stderr, "Didn't received any fd\n");
 395                 ret = -1;
 396                 goto end;
 397         }
 398         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 399                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 400                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 401                 ret = -1;
 402                 goto end;
 403         }
 404         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 405         ret = sizeof_fds;
 406 end:
 407         return ret;
 408 }
 409
 410 /*
 411  * Send a message with credentials over a unix socket.
 412  *
 413  * Returns the size of data sent, or negative error value.
 414  */
 415 LTTNG_HIDDEN
 416 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 417 {
 418         struct msghdr msg;
 419         struct iovec iov[1];
 420         ssize_t ret = -1;
 421 #ifdef __linux__
 422         struct cmsghdr *cmptr;
 423         size_t sizeof_cred = sizeof(lttng_sock_cred);
 424         char anc_buf[CMSG_SPACE(sizeof_cred)];
 425         lttng_sock_cred *creds;
 426
 427         memset(anc_buf, 0, CMSG_SPACE(sizeof_cred) * sizeof(char));
 428 #endif /* __linux__ */
 429
 430         memset(&msg, 0, sizeof(msg));
 431
 432         iov[0].iov_base = buf;
 433         iov[0].iov_len = len;
 434         msg.msg_iov = iov;
 435         msg.msg_iovlen = 1;
 436
 437 #ifdef __linux__
 438         msg.msg_control = (caddr_t) anc_buf;
 439         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 440
 441         cmptr = CMSG_FIRSTHDR(&msg);
 442         if (!cmptr) {
 443                 return -1;
 444         }
 445         cmptr->cmsg_level = SOL_SOCKET;
 446         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 447         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 448
 449         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 450
 451         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 452         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 453         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 454 #endif /* __linux__ */
 455
 456         do {
 457                 ret = sendmsg(sock, &msg, 0);
 458         } while (ret < 0 && errno == EINTR);
 459         if (ret < 0) {
 460                 /*
 461                  * Only warn about EPIPE when quiet mode is deactivated.
 462                  * We consider EPIPE as expected.
 463                  */
 464                 if (errno != EPIPE || !lttng_opt_quiet) {
 465                         PERROR("sendmsg");
 466                 }
 467         }
 468         return ret;
 469 }
 470
 471 /*
 472  * Recv a message accompanied with credentials from a unix socket.
 473  *
 474  * Returns the size of received data, or negative error value.
 475  */
 476 LTTNG_HIDDEN
 477 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 478                 lttng_sock_cred *creds)
 479 {
 480         struct msghdr msg;
 481         struct iovec iov[1];
 482         ssize_t ret;
 483         size_t len_last;
 484 #ifdef __linux__
 485         struct cmsghdr *cmptr;
 486         size_t sizeof_cred = sizeof(lttng_sock_cred);
 487         char anc_buf[CMSG_SPACE(sizeof_cred)];
 488 #endif  /* __linux__ */
 489
 490         memset(&msg, 0, sizeof(msg));
 491
 492         /* Not allowed */
 493         if (creds == NULL) {
 494                 ret = -1;
 495                 goto end;
 496         }
 497
 498         /* Prepare to receive the structures */
 499         iov[0].iov_base = buf;
 500         iov[0].iov_len = len;
 501         msg.msg_iov = iov;
 502         msg.msg_iovlen = 1;
 503
 504 #ifdef __linux__
 505         msg.msg_control = anc_buf;
 506         msg.msg_controllen = sizeof(anc_buf);
 507 #endif /* __linux__ */
 508
 509         do {
 510                 len_last = iov[0].iov_len;
 511                 ret = recvmsg(sock, &msg, 0);
 512                 if (ret > 0) {
 513                         iov[0].iov_base += ret;
 514                         iov[0].iov_len -= ret;
 515                         assert(ret <= len_last);
 516                 }
 517         } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
 518         if (ret < 0) {
 519                 PERROR("recvmsg fds");
 520                 goto end;
 521         } else if (ret > 0) {
 522                 ret = len;
 523         }
 524         /* Else ret = 0 meaning an orderly shutdown. */
 525
 526 #ifdef __linux__
 527         if (msg.msg_flags & MSG_CTRUNC) {
 528                 fprintf(stderr, "Error: Control message truncated.\n");
 529                 ret = -1;
 530                 goto end;
 531         }
 532
 533         cmptr = CMSG_FIRSTHDR(&msg);
 534         if (cmptr == NULL) {
 535                 fprintf(stderr, "Error: Invalid control message header\n");
 536                 ret = -1;
 537                 goto end;
 538         }
 539
 540         if (cmptr->cmsg_level != SOL_SOCKET ||
 541                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 542                 fprintf(stderr, "Didn't received any credentials\n");
 543                 ret = -1;
 544                 goto end;
 545         }
 546
 547         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 548                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 549                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 550                 ret = -1;
 551                 goto end;
 552         }
 553
 554         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 555 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 556         {
 557                 int peer_ret;
 558
 559                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 560                 if (peer_ret != 0) {
 561                         return peer_ret;
 562                 }
 563         }
 564 #else
 565 #error "Please implement credential support for your OS."
 566 #endif  /* __linux__ */
 567
 568 end:
 569         return ret;
 570 }
 571
 572 /*
 573  * Set socket option to use credentials passing.
 574  */
 575 #ifdef __linux__
 576 LTTNG_HIDDEN
 577 int lttcomm_setsockopt_creds_unix_sock(int sock)
 578 {
 579         int ret, on = 1;
 580
 581         /* Set socket for credentials retrieval */
 582         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 583         if (ret < 0) {
 584                 PERROR("setsockopt creds unix sock");
 585         }
 586         return ret;
 587 }
 588 #elif (defined(__FreeBSD__) || defined(__CYGWIN__) || defined(__sun__) || defined(__APPLE__))
 589 LTTNG_HIDDEN
 590 int lttcomm_setsockopt_creds_unix_sock(int sock)
 591 {
 592         return 0;
 593 }
 594 #else
 595 #error "Please implement credential support for your OS."
 596 #endif /* __linux__ */