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_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         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
 136                  * is used in normal execution to detect if sessiond is
 137                  * 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  *      lttcomm_accept_unix_sock
 152  *
 153  *      Do an accept(2) on the sock and return the
 154  *      new file descriptor. The socket MUST be bind(2) before.
 155  */
 156 int lttcomm_accept_unix_sock(int sock)
 157 {
 158         int new_fd;
 159         struct sockaddr_un sun;
 160         socklen_t len = 0;
 161
 162         /* Blocking call */
 163         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 164         if (new_fd < 0) {
 165                 perror("accept");
 166                 goto error;
 167         }
 168
 169         return new_fd;
 170
 171 error:
 172         return -1;
 173 }
 174
 175 /*
 176  *      lttcomm_create_unix_sock
 177  *
 178  *      Creates a AF_UNIX local socket using pathname
 179  *      bind the socket upon creation and return the fd.
 180  */
 181 int lttcomm_create_unix_sock(const char *pathname)
 182 {
 183         struct sockaddr_un sun;
 184         int fd;
 185         int ret = -1;
 186
 187         /* Create server socket */
 188         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 189                 perror("socket");
 190                 goto error;
 191         }
 192
 193         memset(&sun, 0, sizeof(sun));
 194         sun.sun_family = AF_UNIX;
 195         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 196         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 197
 198         /* Unlink the old file if present */
 199         (void) unlink(pathname);
 200         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 201         if (ret < 0) {
 202                 perror("bind");
 203                 goto error;
 204         }
 205
 206         return fd;
 207
 208 error:
 209         return ret;
 210 }
 211
 212 /*
 213  *      lttcomm_listen_unix_sock
 214  *
 215  *      Make the socket listen using MAX_LISTEN.
 216  */
 217 int lttcomm_listen_unix_sock(int sock)
 218 {
 219         int ret;
 220
 221         ret = listen(sock, MAX_LISTEN);
 222         if (ret < 0) {
 223                 perror("listen");
 224         }
 225
 226         return ret;
 227 }
 228
 229 /*
 230  *      lttcomm_recv_unix_sock
 231  *
 232  *  Receive data of size len in put that data into
 233  *  the buf param. Using recvmsg API.
 234  *  Return the size of received data.
 235  */
 236 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 237 {
 238         struct msghdr msg = { 0 };
 239         struct iovec iov[1];
 240         ssize_t ret = -1;
 241
 242         iov[0].iov_base = buf;
 243         iov[0].iov_len = len;
 244         msg.msg_iov = iov;
 245         msg.msg_iovlen = 1;
 246
 247         ret = recvmsg(sock, &msg, 0);
 248         if (ret < 0) {
 249                 perror("recvmsg");
 250         }
 251
 252         return ret;
 253 }
 254
 255 /*
 256  *      lttcomm_send_unix_sock
 257  *
 258  *      Send buf data of size len. Using sendmsg API.
 259  *      Return the size of sent data.
 260  */
 261 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 262 {
 263         struct msghdr msg = { 0 };
 264         struct iovec iov[1];
 265         ssize_t ret = -1;
 266
 267         iov[0].iov_base = buf;
 268         iov[0].iov_len = len;
 269         msg.msg_iov = iov;
 270         msg.msg_iovlen = 1;
 271
 272         ret = sendmsg(sock, &msg, 0);
 273         if (ret < 0) {
 274                 perror("sendmsg");
 275         }
 276
 277         return ret;
 278 }
 279
 280 /*
 281  *  lttcomm_close_unix_sock
 282  *
 283  *  Shutdown cleanly a unix socket.
 284  */
 285 int lttcomm_close_unix_sock(int sock)
 286 {
 287         int ret;
 288
 289         /* Shutdown receptions and transmissions */
 290         ret = shutdown(sock, SHUT_RDWR);
 291         if (ret < 0) {
 292                 perror("shutdown");
 293         }
 294
 295         return ret;
 296 }
 297
 298 /*
 299  *  lttcomm_send_fds_unix_sock
 300  *
 301  *  Send multiple fds on a unix socket.
 302  */
 303 ssize_t lttcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len)
 304 {
 305         struct msghdr msg = { 0 };
 306         struct cmsghdr *cmptr;
 307         struct iovec iov[1];
 308         ssize_t ret = -1;
 309         unsigned int sizeof_fds = nb_fd * sizeof(int);
 310         char tmp[CMSG_SPACE(sizeof_fds)];
 311
 312         /*
 313          * Note: the consumerd receiver only supports receiving one FD per
 314          * message.
 315          */
 316         assert(nb_fd == 1);
 317
 318         msg.msg_control = (caddr_t)tmp;
 319         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 320
 321         cmptr = CMSG_FIRSTHDR(&msg);
 322         cmptr->cmsg_level = SOL_SOCKET;
 323         cmptr->cmsg_type = SCM_RIGHTS;
 324         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 325         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 326         /* Sum of the length of all control messages in the buffer: */
 327         msg.msg_controllen = cmptr->cmsg_len;
 328
 329         iov[0].iov_base = buf;
 330         iov[0].iov_len = len;
 331         msg.msg_iov = iov;
 332         msg.msg_iovlen = 1;
 333
 334         ret = sendmsg(sock, &msg, 0);
 335         if (ret < 0) {
 336                 perror("sendmsg");
 337         }
 338
 339         return ret;
 340 }