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_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
  83         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
  84         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
  85         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
  86         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
  87         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
  88         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
  89         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
  90         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
  91         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
  92         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
  93         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
  94 };
  95
  96 /*
  97  * Return ptr to string representing a human readable error code from the
  98  * lttcomm_return_code enum.
  99  *
 100  * These code MUST be negative in other to treat that as an error value.
 101  */
 102 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 103 {
 104         int tmp_code = -code;
 105
 106         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 107                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 108         }
 109
 110         return "Unknown error code";
 111 }
 112
 113 /*
 114  * Connect to unix socket using the path name.
 115  */
 116 int lttcomm_connect_unix_sock(const char *pathname)
 117 {
 118         struct sockaddr_un sun;
 119         int fd;
 120         int ret;
 121
 122         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 123         if (fd < 0) {
 124                 perror("socket");
 125                 ret = fd;
 126                 goto error;
 127         }
 128
 129         memset(&sun, 0, sizeof(sun));
 130         sun.sun_family = AF_UNIX;
 131         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 132         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 133
 134         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 135         if (ret < 0) {
 136                 /*
 137                  * Don't print message on connect error, because connect is used in
 138                  * normal execution to detect if sessiond is alive.
 139                  */
 140                 goto error_connect;
 141         }
 142
 143         return fd;
 144
 145 error_connect:
 146         close(fd);
 147 error:
 148         return ret;
 149 }
 150
 151 /*
 152  * Do an accept(2) on the sock and return the new file descriptor. The socket
 153  * MUST be bind(2) before.
 154  */
 155 int lttcomm_accept_unix_sock(int sock)
 156 {
 157         int new_fd;
 158         struct sockaddr_un sun;
 159         socklen_t len = 0;
 160
 161         /* Blocking call */
 162         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 163         if (new_fd < 0) {
 164                 perror("accept");
 165                 goto error;
 166         }
 167
 168         return new_fd;
 169
 170 error:
 171         return -1;
 172 }
 173
 174 /*
 175  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 176  * and return the fd.
 177  */
 178 int lttcomm_create_unix_sock(const char *pathname)
 179 {
 180         struct sockaddr_un sun;
 181         int fd;
 182         int ret = -1;
 183
 184         /* Create server socket */
 185         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 186                 perror("socket");
 187                 goto error;
 188         }
 189
 190         memset(&sun, 0, sizeof(sun));
 191         sun.sun_family = AF_UNIX;
 192         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 193         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 194
 195         /* Unlink the old file if present */
 196         (void) unlink(pathname);
 197         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 198         if (ret < 0) {
 199                 perror("bind");
 200                 goto error;
 201         }
 202
 203         return fd;
 204
 205 error:
 206         return ret;
 207 }
 208
 209 /*
 210  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 211  */
 212 int lttcomm_listen_unix_sock(int sock)
 213 {
 214         int ret;
 215
 216         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 217         if (ret < 0) {
 218                 perror("listen");
 219         }
 220
 221         return ret;
 222 }
 223
 224 /*
 225  * Receive data of size len in put that data into the buf param. Using recvmsg
 226  * API.
 227  *
 228  * Return the size of received data.
 229  */
 230 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 231 {
 232         struct msghdr msg = { 0 };
 233         struct iovec iov[1];
 234         ssize_t ret = -1;
 235
 236         iov[0].iov_base = buf;
 237         iov[0].iov_len = len;
 238         msg.msg_iov = iov;
 239         msg.msg_iovlen = 1;
 240
 241         ret = recvmsg(sock, &msg, 0);
 242         if (ret < 0) {
 243                 perror("recvmsg");
 244         }
 245
 246         return ret;
 247 }
 248
 249 /*
 250  * Send buf data of size len. Using sendmsg API.
 251  *
 252  * Return the size of sent data.
 253  */
 254 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 255 {
 256         struct msghdr msg = { 0 };
 257         struct iovec iov[1];
 258         ssize_t ret = -1;
 259
 260         iov[0].iov_base = buf;
 261         iov[0].iov_len = len;
 262         msg.msg_iov = iov;
 263         msg.msg_iovlen = 1;
 264
 265         ret = sendmsg(sock, &msg, 0);
 266         if (ret < 0) {
 267                 perror("sendmsg");
 268         }
 269
 270         return ret;
 271 }
 272
 273 /*
 274  * Shutdown cleanly a unix socket.
 275  */
 276 int lttcomm_close_unix_sock(int sock)
 277 {
 278         int ret;
 279
 280         /* Shutdown receptions and transmissions */
 281         ret = shutdown(sock, SHUT_RDWR);
 282         if (ret < 0) {
 283                 perror("shutdown");
 284         }
 285
 286         return ret;
 287 }
 288
 289 /*
 290  * Send a message accompanied by fd(s) over a unix socket.
 291  *
 292  * Returns the size of data sent, or negative error value.
 293  */
 294 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 295 {
 296         struct msghdr msg = { 0 };
 297         struct cmsghdr *cmptr;
 298         struct iovec iov[1];
 299         ssize_t ret = -1;
 300         unsigned int sizeof_fds = nb_fd * sizeof(int);
 301         char tmp[CMSG_SPACE(sizeof_fds)];
 302         char dummy = 0;
 303
 304         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 305                 return -EINVAL;
 306
 307         msg.msg_control = (caddr_t)tmp;
 308         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 309
 310         cmptr = CMSG_FIRSTHDR(&msg);
 311         cmptr->cmsg_level = SOL_SOCKET;
 312         cmptr->cmsg_type = SCM_RIGHTS;
 313         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 314         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 315         /* Sum of the length of all control messages in the buffer: */
 316         msg.msg_controllen = cmptr->cmsg_len;
 317
 318         iov[0].iov_base = &dummy;
 319         iov[0].iov_len = 1;
 320         msg.msg_iov = iov;
 321         msg.msg_iovlen = 1;
 322
 323         ret = sendmsg(sock, &msg, 0);
 324         if (ret < 0) {
 325                 perror("sendmsg");
 326         }
 327         return ret;
 328 }
 329
 330 /*
 331  * Recv a message accompanied by fd(s) from a unix socket.
 332  *
 333  * Returns the size of received data, or negative error value.
 334  *
 335  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 336  * actually received in nb_fd.
 337  */
 338 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 339 {
 340         struct iovec iov[1];
 341         ssize_t ret = 0;
 342         struct cmsghdr *cmsg;
 343         size_t sizeof_fds = nb_fd * sizeof(int);
 344         char recv_fd[CMSG_SPACE(sizeof_fds)];
 345         struct msghdr msg = { 0 };
 346         char dummy;
 347
 348         /* Prepare to receive the structures */
 349         iov[0].iov_base = &dummy;
 350         iov[0].iov_len = 1;
 351         msg.msg_iov = iov;
 352         msg.msg_iovlen = 1;
 353         msg.msg_control = recv_fd;
 354         msg.msg_controllen = sizeof(recv_fd);
 355
 356         ret = recvmsg(sock, &msg, 0);
 357         if (ret < 0) {
 358                 perror("recvmsg fds");
 359                 goto end;
 360         }
 361         if (ret != 1) {
 362                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 363                                 ret, 1);
 364                 goto end;
 365         }
 366         if (msg.msg_flags & MSG_CTRUNC) {
 367                 fprintf(stderr, "Error: Control message truncated.\n");
 368                 ret = -1;
 369                 goto end;
 370         }
 371         cmsg = CMSG_FIRSTHDR(&msg);
 372         if (!cmsg) {
 373                 fprintf(stderr, "Error: Invalid control message header\n");
 374                 ret = -1;
 375                 goto end;
 376         }
 377         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 378                 fprintf(stderr, "Didn't received any fd\n");
 379                 ret = -1;
 380                 goto end;
 381         }
 382         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 383                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 384                                 cmsg->cmsg_len, CMSG_LEN(sizeof_fds));
 385                 ret = -1;
 386                 goto end;
 387         }
 388         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 389         ret = sizeof_fds;
 390 end:
 391         return ret;
 392 }