| 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 <ust/lttng-ust-abi.h> |
| 27 | #include <lttng-ust-comm.h> |
| 28 | #include <ust/usterr-signal-safe.h> |
| 29 | #include <pthread.h> |
| 30 | |
| 31 | /* Socket from app (connect) to session daemon (listen) for communication */ |
| 32 | static char global_apps_sock_path[PATH_MAX] = DEFAULT_GLOBAL_APPS_UNIX_SOCK; |
| 33 | static pthread_t global_ust_listener; |
| 34 | |
| 35 | /* TODO: allow global_apps_sock_path override */ |
| 36 | |
| 37 | static char local_apps_sock_path[PATH_MAX]; |
| 38 | static pthread_t local_ust_listener; |
| 39 | |
| 40 | static |
| 41 | int setup_local_apps_socket(void) |
| 42 | { |
| 43 | const char *home_dir; |
| 44 | |
| 45 | home_dir = (const char *) getenv("HOME"); |
| 46 | if (!home_dir) |
| 47 | return -ENOENT; |
| 48 | snprintf(local_apps_sock_path, PATH_MAX, |
| 49 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
| 50 | return 0; |
| 51 | } |
| 52 | |
| 53 | static |
| 54 | int register_app_to_sessiond(int socket) |
| 55 | { |
| 56 | ssize_t ret; |
| 57 | struct { |
| 58 | uint32_t major; |
| 59 | uint32_t minor; |
| 60 | pid_t pid; |
| 61 | uid_t uid; |
| 62 | } reg_msg; |
| 63 | |
| 64 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
| 65 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; |
| 66 | reg_msg.pid = getpid(); |
| 67 | reg_msg.uid = getuid(); |
| 68 | |
| 69 | ret = lttcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); |
| 70 | if (ret >= 0 && ret != sizeof(reg_msg)) |
| 71 | return -EIO; |
| 72 | return ret; |
| 73 | } |
| 74 | |
| 75 | |
| 76 | static |
| 77 | int handle_message(int sock, struct lttcomm_ust_msg *lum) |
| 78 | { |
| 79 | ssize_t len; |
| 80 | int ret; |
| 81 | |
| 82 | switch (lum->cmd_type) { |
| 83 | case UST_CREATE_SESSION: |
| 84 | { |
| 85 | struct lttcomm_ust_reply lur; |
| 86 | |
| 87 | DBG("Handling create session message"); |
| 88 | memset(&lur, 0, sizeof(lur)); |
| 89 | lur.cmd_type = UST_CREATE_SESSION; |
| 90 | |
| 91 | /* ... */ |
| 92 | ret = 0; |
| 93 | |
| 94 | if (!ret) |
| 95 | lur.ret_code = LTTCOMM_OK; |
| 96 | else |
| 97 | lur.ret_code = LTTCOMM_SESSION_FAIL; |
| 98 | lur.ret_val = 42; |
| 99 | len = lttcomm_send_unix_sock(sock, &lur, sizeof(lur)); |
| 100 | switch (len) { |
| 101 | case sizeof(lur): |
| 102 | printf("message successfully sent\n"); |
| 103 | break; |
| 104 | case -1: |
| 105 | if (errno == ECONNRESET) { |
| 106 | printf("remote end closed connection\n"); |
| 107 | return 0; |
| 108 | } |
| 109 | return -1; |
| 110 | default: |
| 111 | printf("incorrect message size: %zd\n", len); |
| 112 | return -1; |
| 113 | } |
| 114 | break; |
| 115 | } |
| 116 | default: |
| 117 | ERR("Unimplemented command %d", (int) lum->cmd_type); |
| 118 | return -1; |
| 119 | } |
| 120 | return 0; |
| 121 | } |
| 122 | |
| 123 | static |
| 124 | void *ust_listener_thread(void *arg) |
| 125 | { |
| 126 | const char *sock_path = (const char *) arg; |
| 127 | int sock; |
| 128 | int ret; |
| 129 | |
| 130 | /* Restart trying to connect to the session daemon */ |
| 131 | restart: |
| 132 | |
| 133 | /* Check for sessiond availability with pipe TODO */ |
| 134 | |
| 135 | /* Register */ |
| 136 | ret = lttcomm_connect_unix_sock(sock_path); |
| 137 | if (ret < 0) { |
| 138 | ERR("Error connecting to global apps socket"); |
| 139 | } |
| 140 | sock = ret; |
| 141 | ret = register_app_to_sessiond(sock); |
| 142 | if (ret < 0) { |
| 143 | ERR("Error registering app to local apps socket"); |
| 144 | sleep(5); |
| 145 | goto restart; |
| 146 | } |
| 147 | for (;;) { |
| 148 | ssize_t len; |
| 149 | struct lttcomm_ust_msg lum; |
| 150 | |
| 151 | /* Receive session handle */ |
| 152 | len = lttcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
| 153 | switch (len) { |
| 154 | case 0: /* orderly shutdown */ |
| 155 | DBG("ltt-sessiond has performed an orderly shutdown\n"); |
| 156 | goto end; |
| 157 | case sizeof(lum): |
| 158 | DBG("message received\n"); |
| 159 | ret = handle_message(sock, &lum); |
| 160 | if (ret) { |
| 161 | ERR("Error handling message\n"); |
| 162 | } |
| 163 | continue; |
| 164 | case -1: |
| 165 | if (errno == ECONNRESET) { |
| 166 | ERR("remote end closed connection\n"); |
| 167 | goto end; |
| 168 | } |
| 169 | goto end; |
| 170 | default: |
| 171 | ERR("incorrect message size: %zd\n", len); |
| 172 | continue; |
| 173 | } |
| 174 | |
| 175 | } |
| 176 | end: |
| 177 | ret = close(sock); |
| 178 | if (ret) { |
| 179 | ERR("Error closing local apps socket"); |
| 180 | } |
| 181 | goto restart; /* try to reconnect */ |
| 182 | return NULL; |
| 183 | } |
| 184 | |
| 185 | |
| 186 | /* |
| 187 | * sessiond monitoring thread: monitor presence of global and per-user |
| 188 | * sessiond by polling the application common named pipe. |
| 189 | */ |
| 190 | /* TODO */ |
| 191 | |
| 192 | void __attribute__((constructor)) lttng_ust_comm_init(void) |
| 193 | { |
| 194 | int ret; |
| 195 | |
| 196 | init_usterr(); |
| 197 | |
| 198 | /* Connect to the per-user (local) sessiond apps socket */ |
| 199 | ret = setup_local_apps_socket(); |
| 200 | if (ret) { |
| 201 | ERR("Error setting up to local apps socket"); |
| 202 | } |
| 203 | #if 0 |
| 204 | ret = pthread_create(&global_ust_listener, NULL, |
| 205 | ust_listener_thread, global_apps_sock_path); |
| 206 | #endif //0 |
| 207 | ret = pthread_create(&local_ust_listener, NULL, |
| 208 | ust_listener_thread, local_apps_sock_path); |
| 209 | } |
| 210 | |
| 211 | void __attribute__((destructor)) lttng_ust_comm_exit(void) |
| 212 | { |
| 213 | int ret; |
| 214 | |
| 215 | /* |
| 216 | * Using pthread_cancel here because: |
| 217 | * A) we don't want to hang application teardown. |
| 218 | * B) the thread is not allocating any resource. |
| 219 | */ |
| 220 | ret = pthread_cancel(global_ust_listener); |
| 221 | if (ret) { |
| 222 | ERR("Error cancelling global ust listener thread"); |
| 223 | } |
| 224 | ret = pthread_cancel(local_ust_listener); |
| 225 | if (ret) { |
| 226 | ERR("Error cancelling local ust listener thread"); |
| 227 | } |
| 228 | lttng_ust_abi_exit(); |
| 229 | } |