liblttng-sessiond-comm/lttng-sessiond-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-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_KERN_NA) ] = "Kernel tracer not available",
  56         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
  57         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  58         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  59         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  60         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  73         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  74         [ LTTCOMM_ERR_INDEX(KCONSUMERD_COMMAND_SOCK_READY) ] = "Kconsumerd command socket ready",
  75         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SUCCESS_RECV_FD) ] = "Kconsumerd success on receiving fds",
  76         [ LTTCOMM_ERR_INDEX(KCONSUMERD_ERROR_RECV_FD) ] = "Kconsumerd error on receiving fds",
  77         [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_ERROR) ] = "Kconsumerd error in polling thread",
  78         [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_NVAL) ] = "Kconsumerd polling on closed fd",
  79         [ LTTCOMM_ERR_INDEX(KCONSUMERD_POLL_HUP) ] = "Kconsumerd all fd hung up",
  80         [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_SUCCESS) ] = "Kconsumerd exiting normally",
  81         [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_FAILURE) ] = "Kconsumerd exiting on error",
  82         [ LTTCOMM_ERR_INDEX(KCONSUMERD_OUTFD_ERROR) ] = "Kconsumerd error opening the tracefile",
  83         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EBADF) ] = "Kconsumerd splice EBADF",
  84         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EINVAL) ] = "Kconsumerd splice EINVAL",
  85         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ENOMEM) ] = "Kconsumerd splice ENOMEM",
  86         [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ESPIPE) ] = "Kconsumerd splice ESPIPE",
  87         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
  88 };
  89
  90 /*
  91  *  lttcom_get_readable_code
  92  *
  93  *  Return ptr to string representing a human readable
  94  *  error code from the lttcomm_return_code enum.
  95  *
  96  *  These code MUST be negative in other to treat that
  97  *  as an error value.
  98  */
  99 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 100 {
 101         int tmp_code = -code;
 102
 103         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 104                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 105         }
 106
 107         return "Unknown error code";
 108 }
 109
 110 /*
 111  *      lttcomm_connect_unix_sock
 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
 137                  * is used in normal execution to detect if sessiond is
 138                  * 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  *      lttcomm_accept_unix_sock
 153  *
 154  *      Do an accept(2) on the sock and return the
 155  *      new file descriptor. The socket MUST be bind(2) before.
 156  */
 157 int lttcomm_accept_unix_sock(int sock)
 158 {
 159         int new_fd;
 160         struct sockaddr_un sun;
 161         socklen_t len = 0;
 162
 163         /* Blocking call */
 164         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 165         if (new_fd < 0) {
 166                 perror("accept");
 167                 goto error;
 168         }
 169
 170         return new_fd;
 171
 172 error:
 173         return -1;
 174 }
 175
 176 /*
 177  *      lttcomm_create_unix_sock
 178  *
 179  *      Creates a AF_UNIX local socket using pathname
 180  *      bind the socket upon creation and return the fd.
 181  */
 182 int lttcomm_create_unix_sock(const char *pathname)
 183 {
 184         struct sockaddr_un sun;
 185         int fd;
 186         int ret = -1;
 187
 188         /* Create server socket */
 189         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 190                 perror("socket");
 191                 goto error;
 192         }
 193
 194         memset(&sun, 0, sizeof(sun));
 195         sun.sun_family = AF_UNIX;
 196         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 197         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 198
 199         /* Unlink the old file if present */
 200         (void) unlink(pathname);
 201         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 202         if (ret < 0) {
 203                 perror("bind");
 204                 goto error;
 205         }
 206
 207         return fd;
 208
 209 error:
 210         return ret;
 211 }
 212
 213 /*
 214  *      lttcomm_listen_unix_sock
 215  *
 216  *      Make the socket listen using MAX_LISTEN.
 217  */
 218 int lttcomm_listen_unix_sock(int sock)
 219 {
 220         int ret;
 221
 222         ret = listen(sock, MAX_LISTEN);
 223         if (ret < 0) {
 224                 perror("listen");
 225         }
 226
 227         return ret;
 228 }
 229
 230 /*
 231  *      lttcomm_recv_unix_sock
 232  *
 233  *  Receive data of size len in put that data into
 234  *  the buf param. Using recvmsg API.
 235  *  Return the size of received data.
 236  */
 237 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 238 {
 239         struct msghdr msg = { 0 };
 240         struct iovec iov[1];
 241         ssize_t ret = -1;
 242
 243         iov[0].iov_base = buf;
 244         iov[0].iov_len = len;
 245         msg.msg_iov = iov;
 246         msg.msg_iovlen = 1;
 247
 248         ret = recvmsg(sock, &msg, 0);
 249         if (ret < 0) {
 250                 perror("recvmsg");
 251         }
 252
 253         return ret;
 254 }
 255
 256 /*
 257  *      lttcomm_send_unix_sock
 258  *
 259  *      Send buf data of size len. Using sendmsg API.
 260  *      Return the size of sent data.
 261  */
 262 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 263 {
 264         struct msghdr msg = { 0 };
 265         struct iovec iov[1];
 266         ssize_t ret = -1;
 267
 268         iov[0].iov_base = buf;
 269         iov[0].iov_len = len;
 270         msg.msg_iov = iov;
 271         msg.msg_iovlen = 1;
 272
 273         ret = sendmsg(sock, &msg, 0);
 274         if (ret < 0) {
 275                 perror("sendmsg");
 276         }
 277
 278         return ret;
 279 }
 280
 281 /*
 282  *  lttcomm_close_unix_sock
 283  *
 284  *  Shutdown cleanly a unix socket.
 285  */
 286 int lttcomm_close_unix_sock(int sock)
 287 {
 288         int ret;
 289
 290         /* Shutdown receptions and transmissions */
 291         ret = shutdown(sock, SHUT_RDWR);
 292         if (ret < 0) {
 293                 perror("shutdown");
 294         }
 295
 296         return ret;
 297 }
 298
 299 /*
 300  *  lttcomm_send_fds_unix_sock
 301  *
 302  *  Send multiple fds on a unix socket.
 303  */
 304 ssize_t lttcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len)
 305 {
 306         struct msghdr msg = { 0 };
 307         struct cmsghdr *cmptr;
 308         struct iovec iov[1];
 309         ssize_t ret = -1;
 310         unsigned int sizeof_fds = nb_fd * sizeof(int);
 311         char tmp[CMSG_SPACE(sizeof_fds)];
 312
 313         /*
 314          * Note: the consumerd receiver only supports receiving one FD per
 315          * message.
 316          */
 317         assert(nb_fd == 1);
 318
 319         msg.msg_control = (caddr_t)tmp;
 320         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 321
 322         cmptr = CMSG_FIRSTHDR(&msg);
 323         cmptr->cmsg_level = SOL_SOCKET;
 324         cmptr->cmsg_type = SCM_RIGHTS;
 325         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 326         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 327         /* Sum of the length of all control messages in the buffer: */
 328         msg.msg_controllen = cmptr->cmsg_len;
 329
 330         iov[0].iov_base = buf;
 331         iov[0].iov_len = len;
 332         msg.msg_iov = iov;
 333         msg.msg_iovlen = 1;
 334
 335         ret = sendmsg(sock, &msg, 0);
 336         if (ret < 0) {
 337                 perror("sendmsg");
 338         }
 339
 340         return ret;
 341 }