libust/lttng-ust-comm.c

   1 /*
   2  * lttng-ust-comm.c
   3  *
   4  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   5  * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; only
  10  * version 2.1 of the License.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <sys/types.h>
  23 #include <sys/socket.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <lttng-sessiond-comm.h>
  27 #include <ust/usterr-signal-safe.h>
  28
  29 /* Socket from app (connect) to session daemon (listen) for communication */
  30 static int global_apps_socket = -1;
  31 static char global_apps_sock_path[PATH_MAX] = DEFAULT_GLOBAL_APPS_UNIX_SOCK;
  32
  33 /* TODO: allow global_apps_sock_path override */
  34
  35 static int local_apps_socket = -1;
  36 static char local_apps_sock_path[PATH_MAX];
  37
  38 static
  39 int connect_global_apps_socket(void)
  40 {
  41         int ret;
  42
  43         ret = lttcomm_connect_unix_sock(global_apps_sock_path);
  44         if (ret < 0)
  45                 return ret;
  46         global_apps_socket = ret;
  47
  48         return 0;
  49 }
  50
  51 static
  52 int connect_local_apps_socket(void)
  53 {
  54         const char *home_dir;
  55         int ret;
  56
  57         home_dir = (const char *) getenv("HOME");
  58         if (!home_dir)
  59                 return -ENOENT;
  60         snprintf(local_apps_sock_path, PATH_MAX,
  61                  DEFAULT_HOME_APPS_UNIX_SOCK, home_dir);
  62
  63         ret = lttcomm_connect_unix_sock(local_apps_sock_path);
  64         if (ret < 0)
  65                 return ret;
  66         local_apps_socket = ret;
  67
  68
  69         return 0;
  70 }
  71
  72 static
  73 int register_app_to_sessiond(int socket)
  74 {
  75         ssize_t ret;
  76         struct {
  77                 pid_t pid;
  78                 uid_t uid;
  79         } reg_msg;
  80
  81         reg_msg.pid = getpid();
  82         reg_msg.uid = getuid();
  83
  84         ret = lttcomm_send_unix_sock(socket, &reg_msg, sizeof(reg_msg));
  85         if (ret >= 0 && ret != sizeof(reg_msg))
  86                 return -EIO;
  87         return ret;
  88 }
  89
  90 /*
  91  * sessiond monitoring thread: monitor presence of global and per-user
  92  * sessiond by polling the application common named pipe.
  93  */
  94 /* TODO */
  95
  96 void __attribute__((constructor)) lttng_ust_comm_init(void)
  97 {
  98         int ret;
  99
 100         init_usterr();
 101
 102 #if 0
 103         /* Connect to the global sessiond apps socket */
 104         ret = connect_global_apps_socket();
 105         if (ret) {
 106                 ERR("Error connecting to global apps socket");
 107         }
 108 #endif //0
 109
 110         /* Connect to the per-user (local) sessiond apps socket */
 111         ret = connect_local_apps_socket();
 112         if (ret) {
 113                 ERR("Error connecting to local apps socket");
 114         }
 115
 116         if (global_apps_socket >= 0) {
 117                 ret = register_app_to_sessiond(global_apps_socket);
 118                 if (ret < 0) {
 119                         ERR("Error registering app to global apps socket");
 120                 }
 121         }
 122         if (local_apps_socket >= 0) {
 123                 ret = register_app_to_sessiond(local_apps_socket);
 124                 if (ret < 0) {
 125                         ERR("Error registering app to local apps socket");
 126                 }
 127         }
 128 }
 129
 130 void __attribute__((destructor)) lttng_ust_comm_exit(void)
 131 {
 132         int ret;
 133
 134 #if 0
 135         ERR("dest %d", global_apps_socket);
 136         if (global_apps_socket >= 0) {
 137                 ret = unregister_app_to_sessiond(global_apps_socket);
 138                 if (ret < 0) {
 139                         ERR("Error registering app to global apps socket");
 140                 }
 141                 ret = close(global_apps_socket);
 142                 if (ret) {
 143                         ERR("Error closing global apps socket");
 144                 }
 145         }
 146 #endif
 147         if (local_apps_socket >= 0) {
 148                 ret = close(local_apps_socket);
 149                 if (ret) {
 150                         ERR("Error closing local apps socket");
 151                 }
 152         }
 153 }