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
  31 #include <lttng-sessiond-comm.h>
  32
  33 /*
  34  * Human readable error message.
  35  */
  36 static const char *lttcomm_readable_code[] = {
  37         [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
  38         [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
  39         [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
  40         [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
  41         [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
  42         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
  43         [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
  44         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
  45         [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
  46         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
  47         [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
  48         [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
  49         [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
  50         [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
  51         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
  52         [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
  53         [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
  54         [ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
  55         [ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
  56         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
  57         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
  58         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  59         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  60         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  73         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  74         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  75         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
  76         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
  77         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
  78         [ LTTCOMM_ERR_INDEX(KCONSUMERD_COMMAND_SOCK_READY) ] = "Kconsumerd command socket ready",
  79         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SUCCESS_RECV_FD) ] = "Kconsumerd success on receiving fds",
  80         [ LTTCOMM_ERR_INDEX(KCONSUMERD_ERROR_RECV_FD) ] = "Kconsumerd error on receiving fds",
  81         [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_ERROR) ] = "Kconsumerd error in polling thread",
  82         [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_NVAL) ] = "Kconsumerd polling on closed fd",
  83         [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_HUP) ] = "Kconsumerd all fd hung up",
  84         [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_SUCCESS) ] = "Kconsumerd exiting normally",
  85         [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_FAILURE) ] = "Kconsumerd exiting on error",
  86         [ LTTCOMM_ERR_INDEX(KCONSUMERD_OUTFD_ERROR) ] = "Kconsumerd error opening the tracefile",
  87         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EBADF) ] = "Kconsumerd splice EBADF",
  88         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EINVAL) ] = "Kconsumerd splice EINVAL",
  89         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ENOMEM) ] = "Kconsumerd splice ENOMEM",
  90         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ESPIPE) ] = "Kconsumerd splice ESPIPE",
  91         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
  92 };
  93
  94 /*
  95  * Return ptr to string representing a human readable error code from the
  96  * lttcomm_return_code enum.
  97  *
  98  * These code MUST be negative in other to treat that as an error value.
  99  */
 100 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 101 {
 102         int tmp_code = -code;
 103
 104         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 105                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 106         }
 107
 108         return "Unknown error code";
 109 }
 110
 111 /*
 112  * Connect to unix socket using the path name.
 113  */
 114 int lttcomm_connect_unix_sock(const char *pathname)
 115 {
 116         struct sockaddr_un sun;
 117         int fd;
 118         int ret;
 119
 120         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 121         if (fd < 0) {
 122                 perror("socket");
 123                 ret = fd;
 124                 goto error;
 125         }
 126
 127         memset(&sun, 0, sizeof(sun));
 128         sun.sun_family = AF_UNIX;
 129         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 130         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 131
 132         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 133         if (ret < 0) {
 134                 /*
 135                  * Don't print message on connect error, because connect is used in
 136                  * normal execution to detect if sessiond is alive.
 137                  */
 138                 goto error_connect;
 139         }
 140
 141         return fd;
 142
 143 error_connect:
 144         close(fd);
 145 error:
 146         return ret;
 147 }
 148
 149 /*
 150  * Do an accept(2) on the sock and return the new file descriptor. The socket
 151  * MUST be bind(2) before.
 152  */
 153 int lttcomm_accept_unix_sock(int sock)
 154 {
 155         int new_fd;
 156         struct sockaddr_un sun;
 157         socklen_t len = 0;
 158
 159         /* Blocking call */
 160         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 161         if (new_fd < 0) {
 162                 perror("accept");
 163                 goto error;
 164         }
 165
 166         return new_fd;
 167
 168 error:
 169         return -1;
 170 }
 171
 172 /*
 173  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 174  * and return the fd.
 175  */
 176 int lttcomm_create_unix_sock(const char *pathname)
 177 {
 178         struct sockaddr_un sun;
 179         int fd;
 180         int ret = -1;
 181
 182         /* Create server socket */
 183         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 184                 perror("socket");
 185                 goto error;
 186         }
 187
 188         memset(&sun, 0, sizeof(sun));
 189         sun.sun_family = AF_UNIX;
 190         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 191         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 192
 193         /* Unlink the old file if present */
 194         (void) unlink(pathname);
 195         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 196         if (ret < 0) {
 197                 perror("bind");
 198                 goto error;
 199         }
 200
 201         return fd;
 202
 203 error:
 204         return ret;
 205 }
 206
 207 /*
 208  * Make the socket listen using MAX_LISTEN.
 209  */
 210 int lttcomm_listen_unix_sock(int sock)
 211 {
 212         int ret;
 213
 214         ret = listen(sock, MAX_LISTEN);
 215         if (ret < 0) {
 216                 perror("listen");
 217         }
 218
 219         return ret;
 220 }
 221
 222 /*
 223  * Receive data of size len in put that data into the buf param. Using recvmsg
 224  * API.
 225  *
 226  * Return the size of received data.
 227  */
 228 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 229 {
 230         struct msghdr msg = { 0 };
 231         struct iovec iov[1];
 232         ssize_t ret = -1;
 233
 234         iov[0].iov_base = buf;
 235         iov[0].iov_len = len;
 236         msg.msg_iov = iov;
 237         msg.msg_iovlen = 1;
 238
 239         ret = recvmsg(sock, &msg, 0);
 240         if (ret < 0) {
 241                 perror("recvmsg");
 242         }
 243
 244         return ret;
 245 }
 246
 247 /*
 248  * Send buf data of size len. Using sendmsg API.
 249  *
 250  * Return the size of sent data.
 251  */
 252 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 253 {
 254         struct msghdr msg = { 0 };
 255         struct iovec iov[1];
 256         ssize_t ret = -1;
 257
 258         iov[0].iov_base = buf;
 259         iov[0].iov_len = len;
 260         msg.msg_iov = iov;
 261         msg.msg_iovlen = 1;
 262
 263         ret = sendmsg(sock, &msg, 0);
 264         if (ret < 0) {
 265                 perror("sendmsg");
 266         }
 267
 268         return ret;
 269 }
 270
 271 /*
 272  * Shutdown cleanly a unix socket.
 273  */
 274 int lttcomm_close_unix_sock(int sock)
 275 {
 276         int ret;
 277
 278         /* Shutdown receptions and transmissions */
 279         ret = shutdown(sock, SHUT_RDWR);
 280         if (ret < 0) {
 281                 perror("shutdown");
 282         }
 283
 284         return ret;
 285 }
 286
 287 /*
 288  * Send multiple fds on a unix socket.
 289  */
 290 ssize_t lttcomm_send_fds_unix_sock(int sock, void *buf, int *fds,
 291                 size_t nb_fd, size_t len)
 292 {
 293         struct msghdr msg = { 0 };
 294         struct cmsghdr *cmptr;
 295         struct iovec iov[1];
 296         ssize_t ret = -1;
 297         unsigned int sizeof_fds = nb_fd * sizeof(int);
 298         char tmp[CMSG_SPACE(sizeof_fds)];
 299
 300         /*
 301          * Note: the consumerd receiver only supports receiving one FD per message.
 302          */
 303         assert(nb_fd == 1);
 304
 305         msg.msg_control = (caddr_t)tmp;
 306         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 307
 308         cmptr = CMSG_FIRSTHDR(&msg);
 309         cmptr->cmsg_level = SOL_SOCKET;
 310         cmptr->cmsg_type = SCM_RIGHTS;
 311         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 312         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 313         /* Sum of the length of all control messages in the buffer: */
 314         msg.msg_controllen = cmptr->cmsg_len;
 315
 316         iov[0].iov_base = buf;
 317         iov[0].iov_len = len;
 318         msg.msg_iov = iov;
 319         msg.msg_iovlen = 1;
 320
 321         ret = sendmsg(sock, &msg, 0);
 322         if (ret < 0) {
 323                 perror("sendmsg");
 324         }
 325
 326         return ret;
 327 }
 328
 329 /*
 330  * Receives a single fd from socket.
 331  *
 332  * Returns the size of received data
 333  */
 334 ssize_t lttcomm_recv_fds_unix_sock(int sock, void *buf, int *fds,
 335                 size_t nb_fd, size_t len)
 336 {
 337         struct iovec iov[1];
 338         int data_fd, i, ret = 0;
 339         struct cmsghdr *cmsg;
 340         char recv_fd[CMSG_SPACE(sizeof(int))];
 341         struct msghdr msg = { 0 };
 342         union {
 343                 unsigned char vc[4];
 344                 int vi;
 345         } tmp;
 346
 347         /* Prepare to receive the structures */
 348         iov[0].iov_base = &data_fd;
 349         iov[0].iov_len = sizeof(data_fd);
 350         msg.msg_iov = iov;
 351         msg.msg_iovlen = 1;
 352         msg.msg_control = recv_fd;
 353         msg.msg_controllen = sizeof(recv_fd);
 354
 355         ret = recvmsg(sock, &msg, 0);
 356         if (ret < 0) {
 357                 perror("recvmsg fds");
 358                 goto end;
 359         }
 360
 361         if (ret != sizeof(data_fd)) {
 362                 fprintf(stderr, "Error: Received %d bytes, expected %ld",
 363                                 ret, sizeof(data_fd));
 364                 goto end;
 365         }
 366
 367         cmsg = CMSG_FIRSTHDR(&msg);
 368         if (!cmsg) {
 369                 fprintf(stderr, "Error: Invalid control message header");
 370                 ret = -1;
 371                 goto end;
 372         }
 373
 374         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 375                 fprintf(stderr, "Didn't received any fd");
 376                 ret = -1;
 377                 goto end;
 378         }
 379
 380         /* this is our fd */
 381         for (i = 0; i < sizeof(int); i++) {
 382                 tmp.vc[i] = CMSG_DATA(cmsg)[i];
 383         }
 384
 385         ret = tmp.vi;
 386
 387 end:
 388         return ret;
 389 }