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(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
  97         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
  98         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
  99         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
 100         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
 101         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
 102         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 103         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 104         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 105         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 106         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 107         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 108         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 109         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 110         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 111         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 112         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 113 };
 114
 115 /*
 116  * Return ptr to string representing a human readable error code from the
 117  * lttcomm_return_code enum.
 118  *
 119  * These code MUST be negative in other to treat that as an error value.
 120  */
 121 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 122 {
 123         int tmp_code = -code;
 124
 125         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 126                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 127         }
 128
 129         return "Unknown error code";
 130 }
 131
 132 /*
 133  * Connect to unix socket using the path name.
 134  */
 135 int lttcomm_connect_unix_sock(const char *pathname)
 136 {
 137         struct sockaddr_un sun;
 138         int fd;
 139         int ret;
 140
 141         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 142         if (fd < 0) {
 143                 perror("socket");
 144                 ret = fd;
 145                 goto error;
 146         }
 147
 148         memset(&sun, 0, sizeof(sun));
 149         sun.sun_family = AF_UNIX;
 150         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 151         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 152
 153         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 154         if (ret < 0) {
 155                 /*
 156                  * Don't print message on connect error, because connect is used in
 157                  * normal execution to detect if sessiond is alive.
 158                  */
 159                 goto error_connect;
 160         }
 161
 162         return fd;
 163
 164 error_connect:
 165         close(fd);
 166 error:
 167         return ret;
 168 }
 169
 170 /*
 171  * Do an accept(2) on the sock and return the new file descriptor. The socket
 172  * MUST be bind(2) before.
 173  */
 174 int lttcomm_accept_unix_sock(int sock)
 175 {
 176         int new_fd;
 177         struct sockaddr_un sun;
 178         socklen_t len = 0;
 179
 180         /* Blocking call */
 181         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 182         if (new_fd < 0) {
 183                 perror("accept");
 184                 goto error;
 185         }
 186
 187         return new_fd;
 188
 189 error:
 190         return -1;
 191 }
 192
 193 /*
 194  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 195  * and return the fd.
 196  */
 197 int lttcomm_create_unix_sock(const char *pathname)
 198 {
 199         struct sockaddr_un sun;
 200         int fd;
 201         int ret = -1;
 202
 203         /* Create server socket */
 204         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 205                 perror("socket");
 206                 goto error;
 207         }
 208
 209         memset(&sun, 0, sizeof(sun));
 210         sun.sun_family = AF_UNIX;
 211         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 212         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 213
 214         /* Unlink the old file if present */
 215         (void) unlink(pathname);
 216         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 217         if (ret < 0) {
 218                 perror("bind");
 219                 goto error;
 220         }
 221
 222         return fd;
 223
 224 error:
 225         return ret;
 226 }
 227
 228 /*
 229  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 230  */
 231 int lttcomm_listen_unix_sock(int sock)
 232 {
 233         int ret;
 234
 235         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 236         if (ret < 0) {
 237                 perror("listen");
 238         }
 239
 240         return ret;
 241 }
 242
 243 /*
 244  * Receive data of size len in put that data into the buf param. Using recvmsg
 245  * API.
 246  *
 247  * Return the size of received data.
 248  */
 249 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 250 {
 251         struct msghdr msg = { 0 };
 252         struct iovec iov[1];
 253         ssize_t ret = -1;
 254
 255         iov[0].iov_base = buf;
 256         iov[0].iov_len = len;
 257         msg.msg_iov = iov;
 258         msg.msg_iovlen = 1;
 259
 260         ret = recvmsg(sock, &msg, 0);
 261         if (ret < 0) {
 262                 perror("recvmsg");
 263         }
 264
 265         return ret;
 266 }
 267
 268 /*
 269  * Send buf data of size len. Using sendmsg API.
 270  *
 271  * Return the size of sent data.
 272  */
 273 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 274 {
 275         struct msghdr msg = { 0 };
 276         struct iovec iov[1];
 277         ssize_t ret = -1;
 278
 279         iov[0].iov_base = buf;
 280         iov[0].iov_len = len;
 281         msg.msg_iov = iov;
 282         msg.msg_iovlen = 1;
 283
 284         ret = sendmsg(sock, &msg, 0);
 285         if (ret < 0) {
 286                 perror("sendmsg");
 287         }
 288
 289         return ret;
 290 }
 291
 292 /*
 293  * Shutdown cleanly a unix socket.
 294  */
 295 int lttcomm_close_unix_sock(int sock)
 296 {
 297         int ret;
 298
 299         /* Shutdown receptions and transmissions */
 300         ret = shutdown(sock, SHUT_RDWR);
 301         if (ret < 0) {
 302                 perror("shutdown");
 303         }
 304
 305         return ret;
 306 }
 307
 308 /*
 309  * Send a message accompanied by fd(s) over a unix socket.
 310  *
 311  * Returns the size of data sent, or negative error value.
 312  */
 313 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 314 {
 315         struct msghdr msg = { 0 };
 316         struct cmsghdr *cmptr;
 317         struct iovec iov[1];
 318         ssize_t ret = -1;
 319         unsigned int sizeof_fds = nb_fd * sizeof(int);
 320         char tmp[CMSG_SPACE(sizeof_fds)];
 321         char dummy = 0;
 322
 323         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 324                 return -EINVAL;
 325
 326         msg.msg_control = (caddr_t)tmp;
 327         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 328
 329         cmptr = CMSG_FIRSTHDR(&msg);
 330         cmptr->cmsg_level = SOL_SOCKET;
 331         cmptr->cmsg_type = SCM_RIGHTS;
 332         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 333         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 334         /* Sum of the length of all control messages in the buffer: */
 335         msg.msg_controllen = cmptr->cmsg_len;
 336
 337         iov[0].iov_base = &dummy;
 338         iov[0].iov_len = 1;
 339         msg.msg_iov = iov;
 340         msg.msg_iovlen = 1;
 341
 342         ret = sendmsg(sock, &msg, 0);
 343         if (ret < 0) {
 344                 perror("sendmsg");
 345         }
 346         return ret;
 347 }
 348
 349 /*
 350  * Recv a message accompanied by fd(s) from a unix socket.
 351  *
 352  * Returns the size of received data, or negative error value.
 353  *
 354  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 355  * actually received in nb_fd.
 356  */
 357 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 358 {
 359         struct iovec iov[1];
 360         ssize_t ret = 0;
 361         struct cmsghdr *cmsg;
 362         size_t sizeof_fds = nb_fd * sizeof(int);
 363         char recv_fd[CMSG_SPACE(sizeof_fds)];
 364         struct msghdr msg = { 0 };
 365         char dummy;
 366
 367         /* Prepare to receive the structures */
 368         iov[0].iov_base = &dummy;
 369         iov[0].iov_len = 1;
 370         msg.msg_iov = iov;
 371         msg.msg_iovlen = 1;
 372         msg.msg_control = recv_fd;
 373         msg.msg_controllen = sizeof(recv_fd);
 374
 375         ret = recvmsg(sock, &msg, 0);
 376         if (ret < 0) {
 377                 perror("recvmsg fds");
 378                 goto end;
 379         }
 380         if (ret != 1) {
 381                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 382                                 ret, 1);
 383                 goto end;
 384         }
 385         if (msg.msg_flags & MSG_CTRUNC) {
 386                 fprintf(stderr, "Error: Control message truncated.\n");
 387                 ret = -1;
 388                 goto end;
 389         }
 390         cmsg = CMSG_FIRSTHDR(&msg);
 391         if (!cmsg) {
 392                 fprintf(stderr, "Error: Invalid control message header\n");
 393                 ret = -1;
 394                 goto end;
 395         }
 396         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 397                 fprintf(stderr, "Didn't received any fd\n");
 398                 ret = -1;
 399                 goto end;
 400         }
 401         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 402                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 403                                 cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
 404                 ret = -1;
 405                 goto end;
 406         }
 407         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 408         ret = sizeof_fds;
 409 end:
 410         return ret;
 411 }