1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/* queue.c --
* Copyright 2007,2013,2015 Red Hat Inc., Durham, North Carolina.
* All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors:
* Steve Grubb <sgrubb@redhat.com>
*/
#include "config.h"
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include "queue.h"
static volatile event_t **q;
static pthread_mutex_t queue_lock;
static pthread_cond_t queue_nonempty;
static unsigned int q_next, q_last, q_depth, processing_suspended;
static const char *SINGLE = "1";
static const char *HALT = "0";
static int queue_full_warning = 0;
extern volatile int hup;
#define QUEUE_FULL_LIMIT 5
void reset_suspended(void)
{
processing_suspended = 0;
queue_full_warning = 0;
}
int init_queue(unsigned int size)
{
unsigned int i;
processing_suspended = 0;
q_next = 0;
q_last = 0;
q_depth = size;
q = malloc(q_depth * sizeof(event_t *));
if (q == NULL)
return -1;
for (i=0; i<q_depth; i++)
q[i] = NULL;
/* Setup IPC mechanisms */
pthread_mutex_init(&queue_lock, NULL);
pthread_cond_init(&queue_nonempty, NULL);
return 0;
}
static void change_runlevel(const char *level)
{
char *argv[3];
int pid;
static const char *init_pgm = "/sbin/init";
pid = fork();
if (pid < 0) {
syslog(LOG_ALERT, "Audispd failed to fork switching runlevels");
return;
}
if (pid) /* Parent */
return;
/* Child */
argv[0] = (char *)init_pgm;
argv[1] = (char *)level;
argv[2] = NULL;
execve(init_pgm, argv, NULL);
syslog(LOG_ALERT, "Audispd failed to exec %s", init_pgm);
exit(1);
}
static void do_overflow_action(struct daemon_conf *config)
{
switch (config->overflow_action)
{
case O_IGNORE:
break;
case O_SYSLOG:
if (queue_full_warning < QUEUE_FULL_LIMIT) {
syslog(LOG_ERR,
"queue is full - dropping event");
queue_full_warning++;
if (queue_full_warning == QUEUE_FULL_LIMIT)
syslog(LOG_ERR,
"audispd queue full reporting "
"limit reached - ending "
"dropped event notifications");
}
break;
case O_SUSPEND:
syslog(LOG_ALERT,
"Audispd is suspending event processing due to overflowing its queue.");
processing_suspended = 1;
break;
case O_SINGLE:
syslog(LOG_ALERT,
"Audisp is now changing the system to single user mode due to overflowing its queue");
change_runlevel(SINGLE);
break;
case O_HALT:
syslog(LOG_ALERT,
"Audispd is now halting the system due to overflowing its queue");
change_runlevel(HALT);
break;
default:
syslog(LOG_ALERT, "Unknown overflow action requested");
break;
}
}
void enqueue(event_t *e, struct daemon_conf *config)
{
unsigned int n, retry_cnt = 0;
if (processing_suspended) {
free(e);
return;
}
retry:
// We allow 3 retries and then its over
if (retry_cnt > 3) {
do_overflow_action(config);
free(e);
return;
}
pthread_mutex_lock(&queue_lock);
// OK, have lock add event
n = q_next%q_depth;
if (q[n] == NULL) {
q[n] = e;
q_next = (n+1) % q_depth;
pthread_cond_signal(&queue_nonempty);
pthread_mutex_unlock(&queue_lock);
} else {
pthread_mutex_unlock(&queue_lock);
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = 2 * 1000 * 1000; // 2 milliseconds
nanosleep(&ts, NULL); /* Let other thread try to log it. */
retry_cnt++;
goto retry;
}
}
event_t *dequeue(void)
{
event_t *e;
unsigned int n;
// Wait until its got something in it
pthread_mutex_lock(&queue_lock);
if (hup) {
pthread_mutex_unlock(&queue_lock);
return NULL;
}
n = q_last%q_depth;
if (q[n] == NULL) {
pthread_cond_wait(&queue_nonempty, &queue_lock);
n = q_last%q_depth;
}
// OK, grab the next event
if (q[n] != NULL) {
e = (event_t *)q[n];
q[n] = NULL;
q_last = (n+1) % q_depth;
} else
e = NULL;
pthread_mutex_unlock(&queue_lock);
// Process the event
return e;
}
void nudge_queue(void)
{
pthread_cond_signal(&queue_nonempty);
}
void increase_queue_depth(unsigned int size)
{
pthread_mutex_lock(&queue_lock);
if (size > q_depth) {
int i;
void *tmp_q;
tmp_q = realloc(q, size * sizeof(event_t *));
q = tmp_q;
for (i=q_depth; i<size; i++)
q[i] = NULL;
q_depth = size;
}
pthread_mutex_unlock(&queue_lock);
}
void destroy_queue(void)
{
unsigned int i;
for (i=0; i<q_depth; i++)
free((void *)q[i]);
free(q);
}
|
