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826d496d MD |
1 | /* |
2 | * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca> | |
fac6795d DG |
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. | |
fac6795d DG |
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 | } |