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_NOT_FOUND) ] = "UST channel not found",
  78         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
  79         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
  80         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
  81         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
  82         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
  83         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
  84         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
  85         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
  86         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
  87         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
  88         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
  89         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
  90         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
  91         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
  92         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
  93 };
  94
  95 /*
  96  * Return ptr to string representing a human readable error code from the
  97  * lttcomm_return_code enum.
  98  *
  99  * These code MUST be negative in other to treat that as an error value.
 100  */
 101 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 102 {
 103         int tmp_code = -code;
 104
 105         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 106                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 107         }
 108
 109         return "Unknown error code";
 110 }
 111
 112 /*
 113  * Connect to unix socket using the path name.
 114  */
 115 int lttcomm_connect_unix_sock(const char *pathname)
 116 {
 117         struct sockaddr_un sun;
 118         int fd;
 119         int ret;
 120
 121         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 122         if (fd < 0) {
 123                 perror("socket");
 124                 ret = fd;
 125                 goto error;
 126         }
 127
 128         memset(&sun, 0, sizeof(sun));
 129         sun.sun_family = AF_UNIX;
 130         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 131         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 132
 133         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 134         if (ret < 0) {
 135                 /*
 136                  * Don't print message on connect error, because connect is used in
 137                  * normal execution to detect if sessiond is alive.
 138                  */
 139                 goto error_connect;
 140         }
 141
 142         return fd;
 143
 144 error_connect:
 145         close(fd);
 146 error:
 147         return ret;
 148 }
 149
 150 /*
 151  * Do an accept(2) on the sock and return the new file descriptor. The socket
 152  * MUST be bind(2) before.
 153  */
 154 int lttcomm_accept_unix_sock(int sock)
 155 {
 156         int new_fd;
 157         struct sockaddr_un sun;
 158         socklen_t len = 0;
 159
 160         /* Blocking call */
 161         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 162         if (new_fd < 0) {
 163                 perror("accept");
 164                 goto error;
 165         }
 166
 167         return new_fd;
 168
 169 error:
 170         return -1;
 171 }
 172
 173 /*
 174  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 175  * and return the fd.
 176  */
 177 int lttcomm_create_unix_sock(const char *pathname)
 178 {
 179         struct sockaddr_un sun;
 180         int fd;
 181         int ret = -1;
 182
 183         /* Create server socket */
 184         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 185                 perror("socket");
 186                 goto error;
 187         }
 188
 189         memset(&sun, 0, sizeof(sun));
 190         sun.sun_family = AF_UNIX;
 191         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 192         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 193
 194         /* Unlink the old file if present */
 195         (void) unlink(pathname);
 196         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 197         if (ret < 0) {
 198                 perror("bind");
 199                 goto error;
 200         }
 201
 202         return fd;
 203
 204 error:
 205         return ret;
 206 }
 207
 208 /*
 209  * Make the socket listen using MAX_LISTEN.
 210  */
 211 int lttcomm_listen_unix_sock(int sock)
 212 {
 213         int ret;
 214
 215         ret = listen(sock, MAX_LISTEN);
 216         if (ret < 0) {
 217                 perror("listen");
 218         }
 219
 220         return ret;
 221 }
 222
 223 /*
 224  * Receive data of size len in put that data into the buf param. Using recvmsg
 225  * API.
 226  *
 227  * Return the size of received data.
 228  */
 229 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 230 {
 231         struct msghdr msg = { 0 };
 232         struct iovec iov[1];
 233         ssize_t ret = -1;
 234
 235         iov[0].iov_base = buf;
 236         iov[0].iov_len = len;
 237         msg.msg_iov = iov;
 238         msg.msg_iovlen = 1;
 239
 240         ret = recvmsg(sock, &msg, 0);
 241         if (ret < 0) {
 242                 perror("recvmsg");
 243         }
 244
 245         return ret;
 246 }
 247
 248 /*
 249  * Send buf data of size len. Using sendmsg API.
 250  *
 251  * Return the size of sent data.
 252  */
 253 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 254 {
 255         struct msghdr msg = { 0 };
 256         struct iovec iov[1];
 257         ssize_t ret = -1;
 258
 259         iov[0].iov_base = buf;
 260         iov[0].iov_len = len;
 261         msg.msg_iov = iov;
 262         msg.msg_iovlen = 1;
 263
 264         ret = sendmsg(sock, &msg, 0);
 265         if (ret < 0) {
 266                 perror("sendmsg");
 267         }
 268
 269         return ret;
 270 }
 271
 272 /*
 273  * Shutdown cleanly a unix socket.
 274  */
 275 int lttcomm_close_unix_sock(int sock)
 276 {
 277         int ret;
 278
 279         /* Shutdown receptions and transmissions */
 280         ret = shutdown(sock, SHUT_RDWR);
 281         if (ret < 0) {
 282                 perror("shutdown");
 283         }
 284
 285         return ret;
 286 }
 287
 288 /*
 289  * Send a message accompanied by fd(s) over a unix socket.
 290  *
 291  * Returns the size of data sent, or negative error value.
 292  */
 293 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 294 {
 295         struct msghdr msg = { 0 };
 296         struct cmsghdr *cmptr;
 297         struct iovec iov[1];
 298         ssize_t ret = -1;
 299         unsigned int sizeof_fds = nb_fd * sizeof(int);
 300         char tmp[CMSG_SPACE(sizeof_fds)];
 301         char dummy = 0;
 302
 303         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 304                 return -EINVAL;
 305
 306         msg.msg_control = (caddr_t)tmp;
 307         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 308
 309         cmptr = CMSG_FIRSTHDR(&msg);
 310         cmptr->cmsg_level = SOL_SOCKET;
 311         cmptr->cmsg_type = SCM_RIGHTS;
 312         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 313         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 314         /* Sum of the length of all control messages in the buffer: */
 315         msg.msg_controllen = cmptr->cmsg_len;
 316
 317         iov[0].iov_base = &dummy;
 318         iov[0].iov_len = 1;
 319         msg.msg_iov = iov;
 320         msg.msg_iovlen = 1;
 321
 322         ret = sendmsg(sock, &msg, 0);
 323         if (ret < 0) {
 324                 perror("sendmsg");
 325         }
 326         return ret;
 327 }
 328
 329 /*
 330  * Recv a message accompanied by fd(s) from a unix socket.
 331  *
 332  * Returns the size of received data, or negative error value.
 333  *
 334  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 335  * actually received in nb_fd.
 336  */
 337 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 338 {
 339         struct iovec iov[1];
 340         ssize_t ret = 0;
 341         struct cmsghdr *cmsg;
 342         size_t sizeof_fds = nb_fd * sizeof(int);
 343         char recv_fd[CMSG_SPACE(sizeof_fds)];
 344         struct msghdr msg = { 0 };
 345         char dummy;
 346
 347         /* Prepare to receive the structures */
 348         iov[0].iov_base = &dummy;
 349         iov[0].iov_len = 1;
 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         if (ret != 1) {
 361                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 362                                 ret, 1);
 363                 goto end;
 364         }
 365         if (msg.msg_flags & MSG_CTRUNC) {
 366                 fprintf(stderr, "Error: Control message truncated.\n");
 367                 ret = -1;
 368                 goto end;
 369         }
 370         cmsg = CMSG_FIRSTHDR(&msg);
 371         if (!cmsg) {
 372                 fprintf(stderr, "Error: Invalid control message header\n");
 373                 ret = -1;
 374                 goto end;
 375         }
 376         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 377                 fprintf(stderr, "Didn't received any fd\n");
 378                 ret = -1;
 379                 goto end;
 380         }
 381         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 382                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 383                                 cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
 384                 ret = -1;
 385                 goto end;
 386         }
 387         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 388         ret = sizeof_fds;
 389 end:
 390         return ret;
 391 }