liblttng-sessiond-comm/lttng-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/socket.h>
  26 #include <sys/stat.h>
  27 #include <sys/types.h>
  28 #include <sys/un.h>
  29 #include <unistd.h>
  30 #include <errno.h>
  31
  32 #include <lttng-sessiond-comm.h>
  33
  34 /*
  35  * Human readable error message.
  36  */
  37 static const char *lttcomm_readable_code[] = {
  38         [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
  39         [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
  40         [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
  41         [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
  42         [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
  43         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
  44         [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
  45         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
  46         [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
  47         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
  48         [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
  49         [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
  50         [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
  51         [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
  52         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
  53         [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
  54         [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
  55         [ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
  56         [ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
  57         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
  58         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
  59         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  60         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  73         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  74         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  75         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  76         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
  77         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
  78         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
  79         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
  80         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
  81         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
  82         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
  83         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
  84         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
  85         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
  86         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
  87         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
  88         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
  89         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
  90         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
  91         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
  92         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
  93         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
  94         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
  95         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
  96         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
  97         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
  98         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
  99         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
 100         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 101         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 102         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 103         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 104         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 105         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 106         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 107         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 108         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 109         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 110         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 111 };
 112
 113 /*
 114  * Return ptr to string representing a human readable error code from the
 115  * lttcomm_return_code enum.
 116  *
 117  * These code MUST be negative in other to treat that as an error value.
 118  */
 119 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 120 {
 121         int tmp_code = -code;
 122
 123         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 124                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 125         }
 126
 127         return "Unknown error code";
 128 }
 129
 130 /*
 131  * Connect to unix socket using the path name.
 132  */
 133 int lttcomm_connect_unix_sock(const char *pathname)
 134 {
 135         struct sockaddr_un sun;
 136         int fd;
 137         int ret;
 138
 139         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 140         if (fd < 0) {
 141                 perror("socket");
 142                 ret = fd;
 143                 goto error;
 144         }
 145
 146         memset(&sun, 0, sizeof(sun));
 147         sun.sun_family = AF_UNIX;
 148         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 149         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 150
 151         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 152         if (ret < 0) {
 153                 /*
 154                  * Don't print message on connect error, because connect is used in
 155                  * normal execution to detect if sessiond is alive.
 156                  */
 157                 goto error_connect;
 158         }
 159
 160         return fd;
 161
 162 error_connect:
 163         close(fd);
 164 error:
 165         return ret;
 166 }
 167
 168 /*
 169  * Do an accept(2) on the sock and return the new file descriptor. The socket
 170  * MUST be bind(2) before.
 171  */
 172 int lttcomm_accept_unix_sock(int sock)
 173 {
 174         int new_fd;
 175         struct sockaddr_un sun;
 176         socklen_t len = 0;
 177
 178         /* Blocking call */
 179         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 180         if (new_fd < 0) {
 181                 perror("accept");
 182                 goto error;
 183         }
 184
 185         return new_fd;
 186
 187 error:
 188         return -1;
 189 }
 190
 191 /*
 192  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 193  * and return the fd.
 194  */
 195 int lttcomm_create_unix_sock(const char *pathname)
 196 {
 197         struct sockaddr_un sun;
 198         int fd;
 199         int ret = -1;
 200
 201         /* Create server socket */
 202         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 203                 perror("socket");
 204                 goto error;
 205         }
 206
 207         memset(&sun, 0, sizeof(sun));
 208         sun.sun_family = AF_UNIX;
 209         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 210         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 211
 212         /* Unlink the old file if present */
 213         (void) unlink(pathname);
 214         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 215         if (ret < 0) {
 216                 perror("bind");
 217                 goto error;
 218         }
 219
 220         return fd;
 221
 222 error:
 223         return ret;
 224 }
 225
 226 /*
 227  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 228  */
 229 int lttcomm_listen_unix_sock(int sock)
 230 {
 231         int ret;
 232
 233         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 234         if (ret < 0) {
 235                 perror("listen");
 236         }
 237
 238         return ret;
 239 }
 240
 241 /*
 242  * Receive data of size len in put that data into the buf param. Using recvmsg
 243  * API.
 244  *
 245  * Return the size of received data.
 246  */
 247 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 248 {
 249         struct msghdr msg = { 0 };
 250         struct iovec iov[1];
 251         ssize_t ret = -1;
 252
 253         iov[0].iov_base = buf;
 254         iov[0].iov_len = len;
 255         msg.msg_iov = iov;
 256         msg.msg_iovlen = 1;
 257
 258         ret = recvmsg(sock, &msg, 0);
 259         if (ret < 0) {
 260                 perror("recvmsg");
 261         }
 262
 263         return ret;
 264 }
 265
 266 /*
 267  * Send buf data of size len. Using sendmsg API.
 268  *
 269  * Return the size of sent data.
 270  */
 271 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 272 {
 273         struct msghdr msg = { 0 };
 274         struct iovec iov[1];
 275         ssize_t ret = -1;
 276
 277         iov[0].iov_base = buf;
 278         iov[0].iov_len = len;
 279         msg.msg_iov = iov;
 280         msg.msg_iovlen = 1;
 281
 282         ret = sendmsg(sock, &msg, 0);
 283         if (ret < 0) {
 284                 perror("sendmsg");
 285         }
 286
 287         return ret;
 288 }
 289
 290 /*
 291  * Shutdown cleanly a unix socket.
 292  */
 293 int lttcomm_close_unix_sock(int sock)
 294 {
 295         int ret;
 296
 297         /* Shutdown receptions and transmissions */
 298         ret = shutdown(sock, SHUT_RDWR);
 299         if (ret < 0) {
 300                 perror("shutdown");
 301         }
 302
 303         return ret;
 304 }
 305
 306 /*
 307  * Send a message accompanied by fd(s) over a unix socket.
 308  *
 309  * Returns the size of data sent, or negative error value.
 310  */
 311 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 312 {
 313         struct msghdr msg = { 0 };
 314         struct cmsghdr *cmptr;
 315         struct iovec iov[1];
 316         ssize_t ret = -1;
 317         unsigned int sizeof_fds = nb_fd * sizeof(int);
 318         char tmp[CMSG_SPACE(sizeof_fds)];
 319         char dummy = 0;
 320
 321         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 322                 return -EINVAL;
 323
 324         msg.msg_control = (caddr_t)tmp;
 325         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 326
 327         cmptr = CMSG_FIRSTHDR(&msg);
 328         cmptr->cmsg_level = SOL_SOCKET;
 329         cmptr->cmsg_type = SCM_RIGHTS;
 330         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 331         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 332         /* Sum of the length of all control messages in the buffer: */
 333         msg.msg_controllen = cmptr->cmsg_len;
 334
 335         iov[0].iov_base = &dummy;
 336         iov[0].iov_len = 1;
 337         msg.msg_iov = iov;
 338         msg.msg_iovlen = 1;
 339
 340         ret = sendmsg(sock, &msg, 0);
 341         if (ret < 0) {
 342                 perror("sendmsg");
 343         }
 344         return ret;
 345 }
 346
 347 /*
 348  * Recv a message accompanied by fd(s) from a unix socket.
 349  *
 350  * Returns the size of received data, or negative error value.
 351  *
 352  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 353  * actually received in nb_fd.
 354  */
 355 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 356 {
 357         struct iovec iov[1];
 358         ssize_t ret = 0;
 359         struct cmsghdr *cmsg;
 360         size_t sizeof_fds = nb_fd * sizeof(int);
 361         char recv_fd[CMSG_SPACE(sizeof_fds)];
 362         struct msghdr msg = { 0 };
 363         char dummy;
 364
 365         /* Prepare to receive the structures */
 366         iov[0].iov_base = &dummy;
 367         iov[0].iov_len = 1;
 368         msg.msg_iov = iov;
 369         msg.msg_iovlen = 1;
 370         msg.msg_control = recv_fd;
 371         msg.msg_controllen = sizeof(recv_fd);
 372
 373         ret = recvmsg(sock, &msg, 0);
 374         if (ret < 0) {
 375                 perror("recvmsg fds");
 376                 goto end;
 377         }
 378         if (ret != 1) {
 379                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 380                                 ret, 1);
 381                 goto end;
 382         }
 383         if (msg.msg_flags & MSG_CTRUNC) {
 384                 fprintf(stderr, "Error: Control message truncated.\n");
 385                 ret = -1;
 386                 goto end;
 387         }
 388         cmsg = CMSG_FIRSTHDR(&msg);
 389         if (!cmsg) {
 390                 fprintf(stderr, "Error: Invalid control message header\n");
 391                 ret = -1;
 392                 goto end;
 393         }
 394         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 395                 fprintf(stderr, "Didn't received any fd\n");
 396                 ret = -1;
 397                 goto end;
 398         }
 399         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 400                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 401                                 cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
 402                 ret = -1;
 403                 goto end;
 404         }
 405         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 406         ret = sizeof_fds;
 407 end:
 408         return ret;
 409 }