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