| 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; either version 2 |
| 7 | * of the License, or (at your option) any later version. |
| 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 <errno.h> |
| 21 | #include <grp.h> |
| 22 | #include <stdio.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <string.h> |
| 25 | #include <unistd.h> |
| 26 | |
| 27 | #include <lttng/liblttngctl.h> |
| 28 | |
| 29 | #include "liblttsessiondcomm.h" |
| 30 | #include "lttngerr.h" |
| 31 | |
| 32 | /* Socket to session daemon for communication */ |
| 33 | static int sessiond_socket; |
| 34 | static char sessiond_sock_path[PATH_MAX]; |
| 35 | |
| 36 | /* Communication structure to ltt-sessiond */ |
| 37 | static struct lttcomm_lttng_msg llm; |
| 38 | static struct lttcomm_session_msg lsm; |
| 39 | |
| 40 | /* Prototypes */ |
| 41 | static int check_tracing_group(const char *grp_name); |
| 42 | static int ask_sessiond(void); |
| 43 | static int set_session_daemon_path(void); |
| 44 | static void reset_data_struct(void); |
| 45 | |
| 46 | int lttng_connect_sessiond(void); |
| 47 | int lttng_create_session(const char *name, char *session_id); |
| 48 | int lttng_check_session_daemon(void); |
| 49 | |
| 50 | /* Variables */ |
| 51 | static char *tracing_group; |
| 52 | static int connected; |
| 53 | |
| 54 | /* |
| 55 | * ask_sessiond |
| 56 | * |
| 57 | * Send lttcomm_session_msg to the daemon and wait |
| 58 | * for the reply. Data replied will be put in llm |
| 59 | * |
| 60 | * On success, return 0 |
| 61 | * On error, return error code |
| 62 | */ |
| 63 | static int ask_sessiond(void) |
| 64 | { |
| 65 | int ret; |
| 66 | |
| 67 | if (!connected) { |
| 68 | ret = -ECONNREFUSED; |
| 69 | goto error; |
| 70 | } |
| 71 | |
| 72 | ret = lttcomm_send_unix_sock(sessiond_socket, &lsm, sizeof(lsm)); |
| 73 | if (ret < 0) { |
| 74 | goto error; |
| 75 | } |
| 76 | |
| 77 | ret = lttcomm_recv_unix_sock(sessiond_socket, &llm, sizeof(llm)); |
| 78 | if (ret < 0) { |
| 79 | goto error; |
| 80 | } |
| 81 | |
| 82 | /* Check return code */ |
| 83 | if (llm.ret_code != LTTCOMM_OK) { |
| 84 | ret = -llm.ret_code; |
| 85 | goto error; |
| 86 | } |
| 87 | |
| 88 | return 0; |
| 89 | |
| 90 | error: |
| 91 | return ret; |
| 92 | } |
| 93 | |
| 94 | /* |
| 95 | * lttng_get_readable_code |
| 96 | * |
| 97 | * Return a human readable string of code |
| 98 | */ |
| 99 | const char *lttng_get_readable_code(int code) |
| 100 | { |
| 101 | if (code > -LTTCOMM_OK) { |
| 102 | return "Ended with errors"; |
| 103 | } |
| 104 | |
| 105 | return lttcomm_get_readable_code(code); |
| 106 | } |
| 107 | |
| 108 | /* |
| 109 | * lttng_create_session |
| 110 | * |
| 111 | * Create a tracing session using "name" to the session daemon. |
| 112 | * If no name is given, the auto session creation is set and |
| 113 | * the daemon will take care of finding a name. |
| 114 | * |
| 115 | * On success, return 0 and session_id point to the uuid str. |
| 116 | * On error, negative value is returned. |
| 117 | */ |
| 118 | int lttng_create_session(const char *name, char *session_id) |
| 119 | { |
| 120 | int ret; |
| 121 | |
| 122 | lsm.cmd_type = LTTNG_CREATE_SESSION; |
| 123 | if (name == NULL) { |
| 124 | lsm.u.create_session.auto_session = 1; |
| 125 | } else { |
| 126 | strncpy(lsm.session_name, name, strlen(name)); |
| 127 | lsm.u.create_session.auto_session = 0; |
| 128 | } |
| 129 | |
| 130 | /* Ask the session daemon */ |
| 131 | ret = ask_sessiond(); |
| 132 | if (ret < 0) { |
| 133 | goto end; |
| 134 | } |
| 135 | |
| 136 | /* Unparse session ID */ |
| 137 | uuid_unparse(llm.session_id, session_id); |
| 138 | |
| 139 | end: |
| 140 | reset_data_struct(); |
| 141 | |
| 142 | return ret; |
| 143 | } |
| 144 | |
| 145 | /* |
| 146 | * lttng_ust_list_apps |
| 147 | * |
| 148 | * Ask the session daemon for all UST traceable |
| 149 | * applications. |
| 150 | * |
| 151 | * Return the size of pids. |
| 152 | */ |
| 153 | size_t lttng_ust_list_apps(pid_t **pids) |
| 154 | { |
| 155 | int ret; |
| 156 | |
| 157 | lsm.cmd_type = UST_LIST_APPS; |
| 158 | |
| 159 | ret = ask_sessiond(); |
| 160 | if (ret < 0) { |
| 161 | goto error; |
| 162 | } |
| 163 | |
| 164 | *pids = llm.u.list_apps.pids; |
| 165 | |
| 166 | return llm.u.list_apps.size; |
| 167 | |
| 168 | error: |
| 169 | return ret; |
| 170 | } |
| 171 | |
| 172 | /* |
| 173 | * lttng_connect_sessiond |
| 174 | * |
| 175 | * Connect to the LTTng session daemon. |
| 176 | * On success, return 0 |
| 177 | * On error, return a negative value |
| 178 | */ |
| 179 | int lttng_connect_sessiond(void) |
| 180 | { |
| 181 | int ret; |
| 182 | |
| 183 | ret = set_session_daemon_path(); |
| 184 | if (ret < 0) { |
| 185 | return ret; |
| 186 | } |
| 187 | |
| 188 | /* Connect to the sesssion daemon */ |
| 189 | ret = lttcomm_connect_unix_sock(sessiond_sock_path); |
| 190 | if (ret < 0) { |
| 191 | return ret; |
| 192 | } |
| 193 | |
| 194 | sessiond_socket = ret; |
| 195 | connected = 1; |
| 196 | |
| 197 | return 0; |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * lttng_set_tracing_group |
| 202 | * |
| 203 | * Set tracing group variable with name. This function |
| 204 | * allocate memory pointed by tracing_group. |
| 205 | */ |
| 206 | int lttng_set_tracing_group(const char *name) |
| 207 | { |
| 208 | if (asprintf(&tracing_group, "%s", name) < 0) { |
| 209 | return -ENOMEM; |
| 210 | } |
| 211 | |
| 212 | return 0; |
| 213 | } |
| 214 | |
| 215 | /* |
| 216 | * lttng_check_session_daemon |
| 217 | * |
| 218 | * Return 0 if a sesssion daemon is available |
| 219 | * else return -1 |
| 220 | */ |
| 221 | int lttng_check_session_daemon(void) |
| 222 | { |
| 223 | int ret; |
| 224 | |
| 225 | ret = set_session_daemon_path(); |
| 226 | if (ret < 0) { |
| 227 | return ret; |
| 228 | } |
| 229 | |
| 230 | /* If socket exist, we consider the daemon started */ |
| 231 | ret = access(sessiond_sock_path, F_OK); |
| 232 | if (ret < 0) { |
| 233 | return ret; |
| 234 | } |
| 235 | |
| 236 | return 0; |
| 237 | } |
| 238 | |
| 239 | /* |
| 240 | * reset_data_struct |
| 241 | * |
| 242 | * Reset session daemon structures. |
| 243 | */ |
| 244 | static void reset_data_struct(void) |
| 245 | { |
| 246 | memset(&lsm, 0, sizeof(lsm)); |
| 247 | memset(&llm, 0, sizeof(llm)); |
| 248 | } |
| 249 | |
| 250 | /* |
| 251 | * set_session_daemon_path |
| 252 | * |
| 253 | * Set sessiond socket path by putting it in |
| 254 | * the global sessiond_sock_path variable. |
| 255 | */ |
| 256 | static int set_session_daemon_path(void) |
| 257 | { |
| 258 | int ret; |
| 259 | |
| 260 | /* Are we in the tracing group ? */ |
| 261 | ret = check_tracing_group(tracing_group); |
| 262 | if (ret < 0) { |
| 263 | if (sprintf(sessiond_sock_path, DEFAULT_HOME_CLIENT_UNIX_SOCK, |
| 264 | getenv("HOME")) < 0) { |
| 265 | return -ENOMEM; |
| 266 | } |
| 267 | } else { |
| 268 | strncpy(sessiond_sock_path, DEFAULT_GLOBAL_CLIENT_UNIX_SOCK, |
| 269 | sizeof(DEFAULT_GLOBAL_CLIENT_UNIX_SOCK)); |
| 270 | } |
| 271 | |
| 272 | return 0; |
| 273 | } |
| 274 | |
| 275 | /* |
| 276 | * check_tracing_group |
| 277 | * |
| 278 | * Check if the specified group name exist. |
| 279 | * If yes, 0, else -1 |
| 280 | */ |
| 281 | static int check_tracing_group(const char *grp_name) |
| 282 | { |
| 283 | struct group *grp_tracing; /* no free(). See getgrnam(3) */ |
| 284 | gid_t *grp_list; |
| 285 | int grp_list_size, grp_id, i; |
| 286 | int ret = -1; |
| 287 | |
| 288 | /* Get GID of group 'tracing' */ |
| 289 | grp_tracing = getgrnam(grp_name); |
| 290 | if (grp_tracing == NULL) { |
| 291 | /* NULL means not found also. getgrnam(3) */ |
| 292 | if (errno != 0) { |
| 293 | perror("getgrnam"); |
| 294 | } |
| 295 | goto end; |
| 296 | } |
| 297 | |
| 298 | /* Get number of supplementary group IDs */ |
| 299 | grp_list_size = getgroups(0, NULL); |
| 300 | if (grp_list_size < 0) { |
| 301 | perror("getgroups"); |
| 302 | goto end; |
| 303 | } |
| 304 | |
| 305 | /* Alloc group list of the right size */ |
| 306 | grp_list = malloc(grp_list_size * sizeof(gid_t)); |
| 307 | grp_id = getgroups(grp_list_size, grp_list); |
| 308 | if (grp_id < -1) { |
| 309 | perror("getgroups"); |
| 310 | goto free_list; |
| 311 | } |
| 312 | |
| 313 | for (i = 0; i < grp_list_size; i++) { |
| 314 | if (grp_list[i] == grp_tracing->gr_gid) { |
| 315 | ret = 0; |
| 316 | break; |
| 317 | } |
| 318 | } |
| 319 | |
| 320 | free_list: |
| 321 | free(grp_list); |
| 322 | |
| 323 | end: |
| 324 | return ret; |
| 325 | } |
| 326 | |
| 327 | /* |
| 328 | * lib constructor |
| 329 | */ |
| 330 | static void __attribute__((constructor)) init() |
| 331 | { |
| 332 | /* Set default session group */ |
| 333 | lttng_set_tracing_group(DEFAULT_TRACING_GROUP); |
| 334 | } |