liblttng-ust-comm/lttng-ust-comm.c

   1 /*
   2  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C)  2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; only
   8  * version 2.1 of the License.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #define _GNU_SOURCE
  21 #include <limits.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/socket.h>
  26 #include <sys/stat.h>
  27 #include <sys/types.h>
  28 #include <sys/un.h>
  29 #include <unistd.h>
  30 #include <assert.h>
  31 #include <errno.h>
  32
  33 #include <ust-comm.h>
  34
  35 /*
  36  * Human readable error message.
  37  */
  38 static const char *ustcomm_readable_code[] = {
  39         [ USTCOMM_ERR_INDEX(USTCOMM_ERR) ] = "Unknown error",
  40         [ USTCOMM_ERR_INDEX(USTCOMM_UND) ] = "Undefined command",
  41         [ USTCOMM_ERR_INDEX(USTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
  42         [ USTCOMM_ERR_INDEX(USTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
  43         [ USTCOMM_ERR_INDEX(USTCOMM_NO_SESSION) ] = "No session found",
  44         [ USTCOMM_ERR_INDEX(USTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
  45         [ USTCOMM_ERR_INDEX(USTCOMM_NO_APPS) ] = "No traceable apps found",
  46         [ USTCOMM_ERR_INDEX(USTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
  47         [ USTCOMM_ERR_INDEX(USTCOMM_NO_TRACE) ] = "No trace found",
  48         [ USTCOMM_ERR_INDEX(USTCOMM_FATAL) ] = "Fatal error of the session daemon",
  49         [ USTCOMM_ERR_INDEX(USTCOMM_CREATE_FAIL) ] = "Create trace failed",
  50         [ USTCOMM_ERR_INDEX(USTCOMM_START_FAIL) ] = "Start trace failed",
  51         [ USTCOMM_ERR_INDEX(USTCOMM_STOP_FAIL) ] = "Stop trace failed",
  52         [ USTCOMM_ERR_INDEX(USTCOMM_NO_TRACEABLE) ] = "App is not traceable",
  53         [ USTCOMM_ERR_INDEX(USTCOMM_SELECT_SESS) ] = "A session MUST be selected",
  54         [ USTCOMM_ERR_INDEX(USTCOMM_EXIST_SESS) ] = "Session name already exist",
  55         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_NA) ] = "UST tracer not available",
  56         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_EVENT_EXIST) ] = "UST event already exists",
  57         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_SESS_FAIL) ] = "UST create session failed",
  58         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CHAN_FAIL) ] = "UST create channel failed",
  59         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CHAN_NOT_FOUND) ] = "UST channel not found",
  60         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
  61         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
  62         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CONTEXT_FAIL) ] = "Add UST context failed",
  63         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_ENABLE_FAIL) ] = "Enable UST event failed",
  64         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_DISABLE_FAIL) ] = "Disable UST event failed",
  65         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  66         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_START_FAIL) ] = "Starting UST trace failed",
  67         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_STOP_FAIL) ] = "Stoping UST trace failed",
  68         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CONSUMER_FAIL) ] = "UST consumer start failed",
  69         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_STREAM_FAIL) ] = "UST create stream failed",
  70         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_DIR_FAIL) ] = "UST trace directory creation failed",
  71         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_DIR_EXIST) ] = "UST trace directory already exist",
  72         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_NO_SESSION) ] = "No UST session found",
  73         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_LIST_FAIL) ] = "Listing UST events failed",
  74         [ USTCOMM_ERR_INDEX(USTCONSUMER_COMMAND_SOCK_READY) ] = "UST consumer command socket ready",
  75         [ USTCOMM_ERR_INDEX(USTCONSUMER_SUCCESS_RECV_FD) ] = "UST consumer success on receiving fds",
  76         [ USTCOMM_ERR_INDEX(USTCONSUMER_ERROR_RECV_FD) ] = "UST consumer error on receiving fds",
  77         [ USTCOMM_ERR_INDEX(USTCONSUMER_POLL_ERROR) ] = "UST consumer error in polling thread",
  78         [ USTCOMM_ERR_INDEX(USTCONSUMER_POLL_NVAL) ] = "UST consumer polling on closed fd",
  79         [ USTCOMM_ERR_INDEX(USTCONSUMER_POLL_HUP) ] = "UST consumer all fd hung up",
  80         [ USTCOMM_ERR_INDEX(USTCONSUMER_EXIT_SUCCESS) ] = "UST consumer exiting normally",
  81         [ USTCOMM_ERR_INDEX(USTCONSUMER_EXIT_FAILURE) ] = "UST consumer exiting on error",
  82         [ USTCOMM_ERR_INDEX(USTCONSUMER_OUTFD_ERROR) ] = "UST consumer error opening the tracefile",
  83         [ USTCOMM_ERR_INDEX(USTCONSUMER_SPLICE_EBADF) ] = "UST consumer splice EBADF",
  84         [ USTCOMM_ERR_INDEX(USTCONSUMER_SPLICE_EINVAL) ] = "UST consumer splice EINVAL",
  85         [ USTCOMM_ERR_INDEX(USTCONSUMER_SPLICE_ENOMEM) ] = "UST consumer splice ENOMEM",
  86         [ USTCOMM_ERR_INDEX(USTCONSUMER_SPLICE_ESPIPE) ] = "UST consumer splice ESPIPE",
  87         [ USTCOMM_ERR_INDEX(USTCOMM_NO_EVENT) ] = "Event not found",
  88 };
  89
  90 /*
  91  *  lttcom_get_readable_code
  92  *
  93  *  Return ptr to string representing a human readable
  94  *  error code from the ustcomm_return_code enum.
  95  */
  96 const char *ustcomm_get_readable_code(int code)
  97 {
  98         if (code == USTCOMM_OK) {
  99                 return "Success";
 100         }
 101         if (code >= USTCOMM_ERR && code < USTCOMM_NR) {
 102                 return ustcomm_readable_code[USTCOMM_ERR_INDEX(code)];
 103         }
 104         return strerror(code);
 105 }
 106
 107 /*
 108  *      ustcomm_connect_unix_sock
 109  *
 110  *      Connect to unix socket using the path name.
 111  */
 112 int ustcomm_connect_unix_sock(const char *pathname)
 113 {
 114         struct sockaddr_un sun;
 115         int fd;
 116         int ret;
 117
 118         /*
 119          * libust threads require the close-on-exec flag for all
 120          * resources so it does not leak file descriptors upon exec.
 121          */
 122         fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
 123         if (fd < 0) {
 124                 perror("socket");
 125                 ret = fd;
 126                 goto error;
 127         }
 128
 129         memset(&sun, 0, sizeof(sun));
 130         sun.sun_family = AF_UNIX;
 131         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 132         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 133
 134         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 135         if (ret < 0) {
 136                 /*
 137                  * Don't print message on connect error, because connect
 138                  * is used in normal execution to detect if sessiond is
 139                  * alive.
 140                  */
 141                 goto error_connect;
 142         }
 143
 144         return fd;
 145
 146 error_connect:
 147         close(fd);
 148 error:
 149         return ret;
 150 }
 151
 152 /*
 153  *      ustcomm_accept_unix_sock
 154  *
 155  *      Do an accept(2) on the sock and return the
 156  *      new file descriptor. The socket MUST be bind(2) before.
 157  */
 158 int ustcomm_accept_unix_sock(int sock)
 159 {
 160         int new_fd;
 161         struct sockaddr_un sun;
 162         socklen_t len = 0;
 163
 164         /* Blocking call */
 165         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 166         if (new_fd < 0) {
 167                 perror("accept");
 168                 goto error;
 169         }
 170
 171         return new_fd;
 172
 173 error:
 174         return -1;
 175 }
 176
 177 /*
 178  *      ustcomm_create_unix_sock
 179  *
 180  *      Creates a AF_UNIX local socket using pathname
 181  *      bind the socket upon creation and return the fd.
 182  */
 183 int ustcomm_create_unix_sock(const char *pathname)
 184 {
 185         struct sockaddr_un sun;
 186         int fd;
 187         int ret = -1;
 188
 189         /* Create server socket */
 190         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 191                 perror("socket");
 192                 goto error;
 193         }
 194
 195         memset(&sun, 0, sizeof(sun));
 196         sun.sun_family = AF_UNIX;
 197         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 198         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 199
 200         /* Unlink the old file if present */
 201         (void) unlink(pathname);
 202         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 203         if (ret < 0) {
 204                 perror("bind");
 205                 goto error;
 206         }
 207
 208         return fd;
 209
 210 error:
 211         return ret;
 212 }
 213
 214 /*
 215  *      ustcomm_listen_unix_sock
 216  *
 217  *      Make the socket listen using LTTNG_UST_COMM_MAX_LISTEN.
 218  */
 219 int ustcomm_listen_unix_sock(int sock)
 220 {
 221         int ret;
 222
 223         ret = listen(sock, LTTNG_UST_COMM_MAX_LISTEN);
 224         if (ret < 0) {
 225                 perror("listen");
 226         }
 227
 228         return ret;
 229 }
 230
 231 /*
 232  *      ustcomm_recv_unix_sock
 233  *
 234  *  Receive data of size len in put that data into
 235  *  the buf param. Using recvmsg API.
 236  *  Return the size of received data.
 237  */
 238 ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len)
 239 {
 240         struct msghdr msg;
 241         struct iovec iov[1];
 242         ssize_t ret = -1;
 243
 244         memset(&msg, 0, sizeof(msg));
 245
 246         iov[0].iov_base = buf;
 247         iov[0].iov_len = len;
 248         msg.msg_iov = iov;
 249         msg.msg_iovlen = 1;
 250
 251         do {
 252                 ret = recvmsg(sock, &msg, 0);
 253         } while (ret < 0 && errno == EINTR);
 254         if (ret < 0 && errno != EPIPE) {
 255                 perror("recvmsg");
 256         }
 257
 258         return ret;
 259 }
 260
 261 /*
 262  *      ustcomm_send_unix_sock
 263  *
 264  *      Send buf data of size len. Using sendmsg API.
 265  *      Return the size of sent data.
 266  */
 267 ssize_t ustcomm_send_unix_sock(int sock, void *buf, size_t len)
 268 {
 269         struct msghdr msg;
 270         struct iovec iov[1];
 271         ssize_t ret = -1;
 272
 273         memset(&msg, 0, sizeof(msg));
 274
 275         iov[0].iov_base = buf;
 276         iov[0].iov_len = len;
 277         msg.msg_iov = iov;
 278         msg.msg_iovlen = 1;
 279
 280         /*
 281          * Using the MSG_NOSIGNAL when sending data from sessiond to
 282          * libust, so libust does not receive an unhandled SIGPIPE or
 283          * SIGURG. The sessiond receiver side can be made more resilient
 284          * by ignoring SIGPIPE, but we don't have this luxury on the
 285          * libust side.
 286          */
 287         do {
 288                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 289         } while (ret < 0 && errno == EINTR);
 290         if (ret < 0 && errno != EPIPE) {
 291                 perror("sendmsg");
 292         }
 293
 294         return ret;
 295 }
 296
 297 /*
 298  *  ustcomm_close_unix_sock
 299  *
 300  *  Shutdown cleanly a unix socket.
 301  */
 302 int ustcomm_close_unix_sock(int sock)
 303 {
 304         int ret;
 305
 306         ret = close(sock);
 307         if (ret < 0) {
 308                 perror("close");
 309         }
 310
 311         return ret;
 312 }
 313
 314 /*
 315  *  ustcomm_send_fds_unix_sock
 316  *
 317  *  Send multiple fds on a unix socket.
 318  */
 319 ssize_t ustcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len)
 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
 328         memset(&msg, 0, sizeof(msg));
 329
 330         /*
 331          * Note: the consumerd receiver only supports receiving one FD per
 332          * message.
 333          */
 334         assert(nb_fd == 1);
 335
 336         msg.msg_control = (caddr_t)tmp;
 337         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 338
 339         cmptr = CMSG_FIRSTHDR(&msg);
 340         cmptr->cmsg_level = SOL_SOCKET;
 341         cmptr->cmsg_type = SCM_RIGHTS;
 342         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 343         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 344         /* Sum of the length of all control messages in the buffer: */
 345         msg.msg_controllen = cmptr->cmsg_len;
 346
 347         iov[0].iov_base = buf;
 348         iov[0].iov_len = len;
 349         msg.msg_iov = iov;
 350         msg.msg_iovlen = 1;
 351
 352         do {
 353                 ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 354         } while (ret < 0 && errno == EINTR);
 355         if (ret < 0 && errno != EPIPE) {
 356                 perror("sendmsg");
 357         }
 358
 359         return ret;
 360 }
 361
 362 int ustcomm_send_app_msg(int sock, struct ustcomm_ust_msg *lum)
 363 {
 364         ssize_t len;
 365
 366         len = ustcomm_send_unix_sock(sock, lum, sizeof(*lum));
 367         switch (len) {
 368         case sizeof(*lum):
 369                 break;
 370         case -1:
 371                 if (errno == ECONNRESET) {
 372                         fprintf(stderr, "remote end closed connection\n");
 373                         return 0;
 374                 }
 375                 return -1;
 376         default:
 377                 fprintf(stderr, "incorrect message size: %zd\n", len);
 378                 return -1;
 379         }
 380         return 0;
 381 }
 382
 383 int ustcomm_recv_app_reply(int sock, struct ustcomm_ust_reply *lur,
 384                           uint32_t expected_handle, uint32_t expected_cmd)
 385 {
 386         ssize_t len;
 387
 388         memset(lur, 0, sizeof(*lur));
 389         len = ustcomm_recv_unix_sock(sock, lur, sizeof(*lur));
 390         switch (len) {
 391         case 0: /* orderly shutdown */
 392                 return -EINVAL;
 393         case sizeof(*lur):
 394                 if (lur->handle != expected_handle) {
 395                         fprintf(stderr, "Unexpected result message handle\n");
 396                         return -EINVAL;
 397                 }
 398
 399                 if (lur->cmd != expected_cmd) {
 400                         fprintf(stderr, "Unexpected result message command\n");
 401                         return -EINVAL;
 402                 }
 403                 if (lur->ret_code != USTCOMM_OK) {
 404                         /*
 405                          * Some errors are normal.. we should put this
 406                          * in a debug level message...
 407                          * fprintf(stderr, "remote operation failed with code %d.\n",
 408                          *      lur->ret_code);
 409                          */
 410                         return lur->ret_code;
 411                 }
 412                 return 0;
 413         case -1:
 414                 if (errno == ECONNRESET) {
 415                         fprintf(stderr, "remote end closed connection\n");
 416                         return -EINVAL;
 417                 }
 418                 return -1;
 419         default:
 420                 fprintf(stderr, "incorrect message size: %zd\n", len);
 421                 return len > 0 ? -1 : len;
 422         }
 423 }
 424
 425 int ustcomm_send_app_cmd(int sock,
 426                         struct ustcomm_ust_msg *lum,
 427                         struct ustcomm_ust_reply *lur)
 428 {
 429         int ret;
 430
 431         ret = ustcomm_send_app_msg(sock, lum);
 432         if (ret)
 433                 return ret;
 434         ret = ustcomm_recv_app_reply(sock, lur, lum->handle, lum->cmd);
 435         if (ret)
 436                 return ret;
 437         return 0;
 438 }
 439
 440
 441 /*
 442  * Receives a single fd from socket.
 443  *
 444  * Returns the size of received data
 445  */
 446 int ustcomm_recv_fd(int sock)
 447 {
 448         struct iovec iov[1];
 449         int ret = 0;
 450         int data_fd;
 451         struct cmsghdr *cmsg;
 452         char recv_fd[CMSG_SPACE(sizeof(int))];
 453         struct msghdr msg;
 454         union {
 455                 unsigned char vc[4];
 456                 int vi;
 457         } tmp;
 458         int i;
 459
 460         memset(&msg, 0, sizeof(msg));
 461
 462         /* Prepare to receive the structures */
 463         iov[0].iov_base = &data_fd;
 464         iov[0].iov_len = sizeof(data_fd);
 465         msg.msg_iov = iov;
 466         msg.msg_iovlen = 1;
 467         msg.msg_control = recv_fd;
 468         msg.msg_controllen = sizeof(recv_fd);
 469
 470         do {
 471                 ret = recvmsg(sock, &msg, 0);
 472         } while (ret < 0 && errno == EINTR);
 473         if (ret < 0) {
 474                 if (errno != EPIPE) {
 475                         perror("recvmsg");
 476                 }
 477                 goto end;
 478         }
 479         if (ret != sizeof(data_fd)) {
 480                 fprintf(stderr, "Received %d bytes, expected %zd", ret, sizeof(data_fd));
 481                 goto end;
 482         }
 483         cmsg = CMSG_FIRSTHDR(&msg);
 484         if (!cmsg) {
 485                 fprintf(stderr, "Invalid control message header\n");
 486                 ret = -1;
 487                 goto end;
 488         }
 489         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 490                 fprintf(stderr, "Didn't received any fd\n");
 491                 ret = -1;
 492                 goto end;
 493         }
 494         /* this is our fd */
 495         for (i = 0; i < sizeof(int); i++)
 496                 tmp.vc[i] = CMSG_DATA(cmsg)[i];
 497         ret = tmp.vi;
 498         /*
 499          * Useful for fd leak debug.
 500          * fprintf(stderr, "received fd %d\n", ret);
 501          */
 502 end:
 503         return ret;
 504 }