liblttng-ust-comm/lttng-ust-comm.c

   1 /*
   2  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; only version 2
   7  * of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <limits.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/socket.h>
  25 #include <sys/stat.h>
  26 #include <sys/types.h>
  27 #include <sys/un.h>
  28 #include <unistd.h>
  29 #include <assert.h>
  30
  31 #include <lttng-ust-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_KERN_NA) ] = "Kernel tracer not available",
  55         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
  56         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  57         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  58         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  59         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  60         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  73         [ LTTCOMM_ERR_INDEX(KCONSUMERD_COMMAND_SOCK_READY) ] = "Kconsumerd command socket ready",
  74         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SUCCESS_RECV_FD) ] = "Kconsumerd success on receiving fds",
  75         [ LTTCOMM_ERR_INDEX(KCONSUMERD_ERROR_RECV_FD) ] = "Kconsumerd error on receiving fds",
  76         [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_ERROR) ] = "Kconsumerd error in polling thread",
  77         [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_NVAL) ] = "Kconsumerd polling on closed fd",
  78         [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_HUP) ] = "Kconsumerd all fd hung up",
  79         [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_SUCCESS) ] = "Kconsumerd exiting normally",
  80         [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_FAILURE) ] = "Kconsumerd exiting on error",
  81         [ LTTCOMM_ERR_INDEX(KCONSUMERD_OUTFD_ERROR) ] = "Kconsumerd error opening the tracefile",
  82         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EBADF) ] = "Kconsumerd splice EBADF",
  83         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EINVAL) ] = "Kconsumerd splice EINVAL",
  84         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ENOMEM) ] = "Kconsumerd splice ENOMEM",
  85         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ESPIPE) ] = "Kconsumerd splice ESPIPE",
  86         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
  87 };
  88
  89 /*
  90  *  lttcom_get_readable_code
  91  *
  92  *  Return ptr to string representing a human readable
  93  *  error code from the lttcomm_return_code enum.
  94  *
  95  *  These code MUST be negative in other to treat that
  96  *  as an error value.
  97  */
  98 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
  99 {
 100         int tmp_code = -code;
 101
 102         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 103                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 104         }
 105
 106         return "Unknown error code";
 107 }
 108
 109 /*
 110  *      lttcomm_connect_unix_sock
 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         /*
 121          * libust threads require the close-on-exec flag for all
 122          * resources so it does not leak file descriptors upon exec.
 123          */
 124         fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
 125         if (fd < 0) {
 126                 perror("socket");
 127                 ret = fd;
 128                 goto error;
 129         }
 130
 131         memset(&sun, 0, sizeof(sun));
 132         sun.sun_family = AF_UNIX;
 133         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 134         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 135
 136         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 137         if (ret < 0) {
 138                 /*
 139                  * Don't print message on connect error, because connect
 140                  * is used in normal execution to detect if sessiond is
 141                  * alive.
 142                  */
 143                 goto error_connect;
 144         }
 145
 146         return fd;
 147
 148 error_connect:
 149         close(fd);
 150 error:
 151         return ret;
 152 }
 153
 154 /*
 155  *      lttcomm_accept_unix_sock
 156  *
 157  *      Do an accept(2) on the sock and return the
 158  *      new file descriptor. The socket MUST be bind(2) before.
 159  */
 160 int lttcomm_accept_unix_sock(int sock)
 161 {
 162         int new_fd;
 163         struct sockaddr_un sun;
 164         socklen_t len = 0;
 165
 166         /* Blocking call */
 167         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 168         if (new_fd < 0) {
 169                 perror("accept");
 170                 goto error;
 171         }
 172
 173         return new_fd;
 174
 175 error:
 176         return -1;
 177 }
 178
 179 /*
 180  *      lttcomm_create_unix_sock
 181  *
 182  *      Creates a AF_UNIX local socket using pathname
 183  *      bind the socket upon creation and return the fd.
 184  */
 185 int lttcomm_create_unix_sock(const char *pathname)
 186 {
 187         struct sockaddr_un sun;
 188         int fd;
 189         int ret = -1;
 190
 191         /* Create server socket */
 192         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 193                 perror("socket");
 194                 goto error;
 195         }
 196
 197         memset(&sun, 0, sizeof(sun));
 198         sun.sun_family = AF_UNIX;
 199         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 200         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 201
 202         /* Unlink the old file if present */
 203         (void) unlink(pathname);
 204         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 205         if (ret < 0) {
 206                 perror("bind");
 207                 goto error;
 208         }
 209
 210         return fd;
 211
 212 error:
 213         return ret;
 214 }
 215
 216 /*
 217  *      lttcomm_listen_unix_sock
 218  *
 219  *      Make the socket listen using MAX_LISTEN.
 220  */
 221 int lttcomm_listen_unix_sock(int sock)
 222 {
 223         int ret;
 224
 225         ret = listen(sock, MAX_LISTEN);
 226         if (ret < 0) {
 227                 perror("listen");
 228         }
 229
 230         return ret;
 231 }
 232
 233 /*
 234  *      lttcomm_recv_unix_sock
 235  *
 236  *  Receive data of size len in put that data into
 237  *  the buf param. Using recvmsg API.
 238  *  Return the size of received data.
 239  */
 240 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 241 {
 242         struct msghdr msg = { 0 };
 243         struct iovec iov[1];
 244         ssize_t ret = -1;
 245
 246         iov[0].iov_base = buf;
 247         iov[0].iov_len = len;
 248         msg.msg_iov = iov;
 249         msg.msg_iovlen = 1;
 250
 251         ret = recvmsg(sock, &msg, 0);
 252         if (ret < 0) {
 253                 perror("recvmsg");
 254         }
 255
 256         return ret;
 257 }
 258
 259 /*
 260  *      lttcomm_send_unix_sock
 261  *
 262  *      Send buf data of size len. Using sendmsg API.
 263  *      Return the size of sent data.
 264  */
 265 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 266 {
 267         struct msghdr msg = { 0 };
 268         struct iovec iov[1];
 269         ssize_t ret = -1;
 270
 271         iov[0].iov_base = buf;
 272         iov[0].iov_len = len;
 273         msg.msg_iov = iov;
 274         msg.msg_iovlen = 1;
 275
 276         /*
 277          * Using the MSG_NOSIGNAL when sending data from sessiond to
 278          * libust, so libust does not receive an unhandled SIGPIPE or
 279          * SIGURG. The sessiond receiver side can be made more resilient
 280          * by ignoring SIGPIPE, but we don't have this luxury on the
 281          * libust side.
 282          */
 283         ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 284         if (ret < 0) {
 285                 perror("sendmsg");
 286         }
 287
 288         return ret;
 289 }
 290
 291 /*
 292  *  lttcomm_close_unix_sock
 293  *
 294  *  Shutdown cleanly a unix socket.
 295  */
 296 int lttcomm_close_unix_sock(int sock)
 297 {
 298         int ret;
 299
 300         /* Shutdown receptions and transmissions */
 301         ret = shutdown(sock, SHUT_RDWR);
 302         if (ret < 0) {
 303                 perror("shutdown");
 304         }
 305
 306         return ret;
 307 }
 308
 309 /*
 310  *  lttcomm_send_fds_unix_sock
 311  *
 312  *  Send multiple fds on a unix socket.
 313  */
 314 ssize_t lttcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len)
 315 {
 316         struct msghdr msg = { 0 };
 317         struct cmsghdr *cmptr;
 318         struct iovec iov[1];
 319         ssize_t ret = -1;
 320         unsigned int sizeof_fds = nb_fd * sizeof(int);
 321         char tmp[CMSG_SPACE(sizeof_fds)];
 322
 323         /*
 324          * Note: the consumerd receiver only supports receiving one FD per
 325          * message.
 326          */
 327         assert(nb_fd == 1);
 328
 329         msg.msg_control = (caddr_t)tmp;
 330         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 331
 332         cmptr = CMSG_FIRSTHDR(&msg);
 333         cmptr->cmsg_level = SOL_SOCKET;
 334         cmptr->cmsg_type = SCM_RIGHTS;
 335         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 336         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 337         /* Sum of the length of all control messages in the buffer: */
 338         msg.msg_controllen = cmptr->cmsg_len;
 339
 340         iov[0].iov_base = buf;
 341         iov[0].iov_len = len;
 342         msg.msg_iov = iov;
 343         msg.msg_iovlen = 1;
 344
 345         ret = sendmsg(sock, &msg, 0);
 346         if (ret < 0) {
 347                 perror("sendmsg");
 348         }
 349
 350         return ret;
 351 }