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(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
  96         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
  97         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
  98         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
  99         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 100         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 101         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 102         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 103         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 104         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 105         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 106         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 107         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 108         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 109         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 110 };
 111
 112 /*
 113  * Return ptr to string representing a human readable error code from the
 114  * lttcomm_return_code enum.
 115  *
 116  * These code MUST be negative in other to treat that as an error value.
 117  */
 118 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 119 {
 120         int tmp_code = -code;
 121
 122         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 123                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 124         }
 125
 126         return "Unknown error code";
 127 }
 128
 129 /*
 130  * Connect to unix socket using the path name.
 131  */
 132 int lttcomm_connect_unix_sock(const char *pathname)
 133 {
 134         struct sockaddr_un sun;
 135         int fd;
 136         int ret;
 137
 138         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 139         if (fd < 0) {
 140                 perror("socket");
 141                 ret = fd;
 142                 goto error;
 143         }
 144
 145         memset(&sun, 0, sizeof(sun));
 146         sun.sun_family = AF_UNIX;
 147         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 148         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 149
 150         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 151         if (ret < 0) {
 152                 /*
 153                  * Don't print message on connect error, because connect is used in
 154                  * normal execution to detect if sessiond is alive.
 155                  */
 156                 goto error_connect;
 157         }
 158
 159         return fd;
 160
 161 error_connect:
 162         close(fd);
 163 error:
 164         return ret;
 165 }
 166
 167 /*
 168  * Do an accept(2) on the sock and return the new file descriptor. The socket
 169  * MUST be bind(2) before.
 170  */
 171 int lttcomm_accept_unix_sock(int sock)
 172 {
 173         int new_fd;
 174         struct sockaddr_un sun;
 175         socklen_t len = 0;
 176
 177         /* Blocking call */
 178         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 179         if (new_fd < 0) {
 180                 perror("accept");
 181                 goto error;
 182         }
 183
 184         return new_fd;
 185
 186 error:
 187         return -1;
 188 }
 189
 190 /*
 191  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 192  * and return the fd.
 193  */
 194 int lttcomm_create_unix_sock(const char *pathname)
 195 {
 196         struct sockaddr_un sun;
 197         int fd;
 198         int ret = -1;
 199
 200         /* Create server socket */
 201         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 202                 perror("socket");
 203                 goto error;
 204         }
 205
 206         memset(&sun, 0, sizeof(sun));
 207         sun.sun_family = AF_UNIX;
 208         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 209         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 210
 211         /* Unlink the old file if present */
 212         (void) unlink(pathname);
 213         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 214         if (ret < 0) {
 215                 perror("bind");
 216                 goto error;
 217         }
 218
 219         return fd;
 220
 221 error:
 222         return ret;
 223 }
 224
 225 /*
 226  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 227  */
 228 int lttcomm_listen_unix_sock(int sock)
 229 {
 230         int ret;
 231
 232         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 233         if (ret < 0) {
 234                 perror("listen");
 235         }
 236
 237         return ret;
 238 }
 239
 240 /*
 241  * Receive data of size len in put that data into the buf param. Using recvmsg
 242  * API.
 243  *
 244  * Return the size of received data.
 245  */
 246 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 247 {
 248         struct msghdr msg = { 0 };
 249         struct iovec iov[1];
 250         ssize_t ret = -1;
 251
 252         iov[0].iov_base = buf;
 253         iov[0].iov_len = len;
 254         msg.msg_iov = iov;
 255         msg.msg_iovlen = 1;
 256
 257         ret = recvmsg(sock, &msg, 0);
 258         if (ret < 0) {
 259                 perror("recvmsg");
 260         }
 261
 262         return ret;
 263 }
 264
 265 /*
 266  * Send buf data of size len. Using sendmsg API.
 267  *
 268  * Return the size of sent data.
 269  */
 270 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 271 {
 272         struct msghdr msg = { 0 };
 273         struct iovec iov[1];
 274         ssize_t ret = -1;
 275
 276         iov[0].iov_base = buf;
 277         iov[0].iov_len = len;
 278         msg.msg_iov = iov;
 279         msg.msg_iovlen = 1;
 280
 281         ret = sendmsg(sock, &msg, 0);
 282         if (ret < 0) {
 283                 perror("sendmsg");
 284         }
 285
 286         return ret;
 287 }
 288
 289 /*
 290  * Shutdown cleanly a unix socket.
 291  */
 292 int lttcomm_close_unix_sock(int sock)
 293 {
 294         int ret;
 295
 296         /* Shutdown receptions and transmissions */
 297         ret = shutdown(sock, SHUT_RDWR);
 298         if (ret < 0) {
 299                 perror("shutdown");
 300         }
 301
 302         return ret;
 303 }
 304
 305 /*
 306  * Send a message accompanied by fd(s) over a unix socket.
 307  *
 308  * Returns the size of data sent, or negative error value.
 309  */
 310 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 311 {
 312         struct msghdr msg = { 0 };
 313         struct cmsghdr *cmptr;
 314         struct iovec iov[1];
 315         ssize_t ret = -1;
 316         unsigned int sizeof_fds = nb_fd * sizeof(int);
 317         char tmp[CMSG_SPACE(sizeof_fds)];
 318         char dummy = 0;
 319
 320         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 321                 return -EINVAL;
 322
 323         msg.msg_control = (caddr_t)tmp;
 324         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 325
 326         cmptr = CMSG_FIRSTHDR(&msg);
 327         cmptr->cmsg_level = SOL_SOCKET;
 328         cmptr->cmsg_type = SCM_RIGHTS;
 329         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 330         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 331         /* Sum of the length of all control messages in the buffer: */
 332         msg.msg_controllen = cmptr->cmsg_len;
 333
 334         iov[0].iov_base = &dummy;
 335         iov[0].iov_len = 1;
 336         msg.msg_iov = iov;
 337         msg.msg_iovlen = 1;
 338
 339         ret = sendmsg(sock, &msg, 0);
 340         if (ret < 0) {
 341                 perror("sendmsg");
 342         }
 343         return ret;
 344 }
 345
 346 /*
 347  * Recv a message accompanied by fd(s) from a unix socket.
 348  *
 349  * Returns the size of received data, or negative error value.
 350  *
 351  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 352  * actually received in nb_fd.
 353  */
 354 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 355 {
 356         struct iovec iov[1];
 357         ssize_t ret = 0;
 358         struct cmsghdr *cmsg;
 359         size_t sizeof_fds = nb_fd * sizeof(int);
 360         char recv_fd[CMSG_SPACE(sizeof_fds)];
 361         struct msghdr msg = { 0 };
 362         char dummy;
 363
 364         /* Prepare to receive the structures */
 365         iov[0].iov_base = &dummy;
 366         iov[0].iov_len = 1;
 367         msg.msg_iov = iov;
 368         msg.msg_iovlen = 1;
 369         msg.msg_control = recv_fd;
 370         msg.msg_controllen = sizeof(recv_fd);
 371
 372         ret = recvmsg(sock, &msg, 0);
 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                                 cmsg->cmsg_len, 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 }