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
|
/***************************************************************************
* Copyright (C) 2007 International Business Machines Corp. *
* All Rights Reserved. *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program 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 General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
* *
* Authors: *
* Klaus Heinrich Kiwi <klausk@br.ibm.com> *
* based on code by Steve Grubb <sgrubb@redhat.com> *
***************************************************************************/
#include "zos-remote-queue.h"
#include <stdlib.h>
#include <pthread.h>
#include <syslog.h>
#include "zos-remote-log.h"
static volatile BerElement **q;
static pthread_mutex_t queue_lock;
static pthread_cond_t queue_nonempty;
static unsigned int q_next, q_last, q_depth;
int init_queue(unsigned int size)
{
unsigned int i;
q_next = 0;
q_last = 0;
q_depth = size;
q = malloc(q_depth * sizeof(BerElement *));
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;
}
void enqueue(BerElement *ber)
{
unsigned int n, retry_cnt = 0;
retry:
/* We allow 3 retries and then its over */
if (retry_cnt > 3) {
log_err("queue is full - dropping event");
return;
}
pthread_mutex_lock(&queue_lock);
/* OK, have lock add event */
n = q_next%q_depth;
if (q[n] == NULL) {
q[n] = ber;
q_next = (n+1) % q_depth;
pthread_cond_signal(&queue_nonempty);
pthread_mutex_unlock(&queue_lock);
} else {
pthread_mutex_unlock(&queue_lock);
pthread_yield(); /* Let dequeue thread run to clear queue */
retry_cnt++;
goto retry;
}
}
BerElement *dequeue(void)
{
BerElement *ber;
unsigned int n;
/* Wait until its got something in it */
pthread_mutex_lock(&queue_lock);
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) {
ber = (BerElement *) q[n];
q[n] = NULL;
q_last = (n+1) % q_depth;
} else
ber = NULL;
pthread_mutex_unlock(&queue_lock);
/* Process the event */
return ber;
}
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) {
unsigned int i;
void *tmp_q;
tmp_q = realloc(q, size * sizeof(BerElement *));
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++) {
ber_free(q[i], 1);
}
free(q);
}
|
