Add lttng-kernel header
[lttng-tools.git] / ltt-sessiond / traceable-app.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; 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 <pthread.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <urcu/list.h>
25
26 #include "lttngerr.h"
27 #include "traceable-app.h"
28
29 /* Number of element for the list below. */
30 static unsigned int traceable_app_count;
31
32 /* Init ust traceabl application's list */
33 struct ltt_traceable_app_list ltt_traceable_app_list = {
34 .head = CDS_LIST_HEAD_INIT(ltt_traceable_app_list.head),
35 };
36
37 /* List mutex */
38 pthread_mutex_t ltt_traceable_app_list_mutex;
39
40 /* Internal function */
41 static void add_traceable_app(struct ltt_traceable_app *lta);
42 static void del_traceable_app(struct ltt_traceable_app *lta);
43
44 /*
45 * add_traceable_app
46 *
47 * Add a traceable application structure to the global
48 * list protected by a mutex.
49 */
50 static void add_traceable_app(struct ltt_traceable_app *lta)
51 {
52 pthread_mutex_lock(&ltt_traceable_app_list_mutex);
53 cds_list_add(&lta->list, &ltt_traceable_app_list.head);
54 traceable_app_count++;
55 pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
56 }
57
58 /*
59 * del_traceable_app
60 *
61 * Delete a traceable application structure from the
62 * global list protected by a mutex.
63 */
64 static void del_traceable_app(struct ltt_traceable_app *lta)
65 {
66 pthread_mutex_lock(&ltt_traceable_app_list_mutex);
67 cds_list_del(&lta->list);
68 /* Sanity check */
69 if (traceable_app_count != 0) {
70 traceable_app_count--;
71 }
72 pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
73 }
74
75 /*
76 * register_traceable_app
77 *
78 * Using pid and uid (of the app), allocate
79 * a new ltt_traceable_app struct and add it
80 * to the global traceable app list.
81 *
82 * On success, return 0, else return malloc ENOMEM.
83 */
84 int register_traceable_app(pid_t pid, uid_t uid)
85 {
86 struct ltt_traceable_app *lta;
87
88 lta = malloc(sizeof(struct ltt_traceable_app));
89 if (lta == NULL) {
90 perror("malloc");
91 return -ENOMEM;
92 }
93
94 lta->uid = uid;
95 lta->pid = pid;
96 add_traceable_app(lta);
97 DBG("Application %d registered with UID %d", pid, uid);
98
99 return 0;
100 }
101
102 /*
103 * unregister_traceable_app
104 *
105 * Unregister app by removing it from the global
106 * traceable app list and freeing the data struct.
107 */
108 void unregister_traceable_app(pid_t pid)
109 {
110 struct ltt_traceable_app *lta;
111
112 lta = find_app_by_pid(pid);
113 if (lta != NULL) {
114 del_traceable_app(lta);
115 free(lta);
116 DBG("PID %d unregistered", pid);
117 }
118 }
119
120 /*
121 * get_app_count
122 *
123 * Return traceable_app_count
124 */
125 unsigned int get_app_count(void)
126 {
127 return traceable_app_count;
128 }
129
130 /*
131 * find_app_by_pid
132 *
133 * Iterate over the traceable apps list and
134 * return a pointer or NULL if not found.
135 */
136 struct ltt_traceable_app *find_app_by_pid(pid_t pid)
137 {
138 struct ltt_traceable_app *iter;
139
140 pthread_mutex_lock(&ltt_traceable_app_list_mutex);
141 cds_list_for_each_entry(iter, &ltt_traceable_app_list.head, list) {
142 if (iter->pid == pid) {
143 pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
144 /* Found */
145 return iter;
146 }
147 }
148 pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
149
150 return NULL;
151 }
152
153 /*
154 * get_app_list_pids
155 *
156 * List traceable user-space application and fill an
157 * array of pids.
158 */
159 void get_app_list_pids(pid_t *pids)
160 {
161 int i = 0;
162 struct ltt_traceable_app *iter;
163
164 /* Protected by a mutex here because the threads manage_client
165 * and manage_apps can access this list.
166 */
167 pthread_mutex_lock(&ltt_traceable_app_list_mutex);
168 cds_list_for_each_entry(iter, &ltt_traceable_app_list.head, list) {
169 pids[i] = iter->pid;
170 i++;
171 }
172 pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
173 }
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