nodelist.c

linux/unix下c/s形式的资源监视,客户端负责搜集机器,再传送到服务端.

/*
 *  Monitor-Server/nodelist.c
 *
 *  Copyright (C) 2004 Jian Shen <[e-mail]>
 */

#include "nodelist.h"
#include "statfile.h"

#include <linux/time.h>
#include <linux/slab.h>
#include <asm/semaphore.h>

static struct node_entry* nlist_head = NULL;
static struct node_entry* nlist_tail = NULL;

struct semaphore nlist_mutex;

void nlist_init()
{
	sema_init(&nlist_mutex, 1);
}

static void nlist_lock()
{
	down(&nlist_mutex);
}

static void nlist_unlock()
{
	up(&nlist_mutex);
}

static void add(const char* host_ip, system_load_info* sysload)
{
	struct node_entry* p;
	struct timeval tm;

	if(nlist_head == NULL) {
		nlist_head = (struct node_entry*)kmalloc(sizeof(struct node_entry), GFP_KERNEL);
		if(nlist_head == NULL) {
			printk(KERN_ERR "kmalloc failed.\n");
			return;
		}

		strcpy(nlist_head->host, host_ip);

		nlist_head->sysload = (system_load_info*)kmalloc(sizeof(system_load_info), GFP_KERNEL);
		if(nlist_head->sysload == NULL) {
			kfree(nlist_head);
			nlist_head = NULL;
			return;
		}
		memcpy(nlist_head->sysload, sysload, sizeof(system_load_info));

		do_gettimeofday(&tm);
		nlist_head->timestamp = tm.tv_sec;

		nlist_head->prev = NULL;
		nlist_head->next = NULL;

		nlist_tail = nlist_head;

		p = nlist_head;
	}else {
		p = (struct node_entry*)kmalloc(sizeof(struct node_entry), GFP_KERNEL);
		if(p == NULL) {
			printk(KERN_ERR "kmalloc failed.\n");
			return;
		}

		strcpy(p->host, host_ip);

		p->sysload = (system_load_info*)kmalloc(sizeof(system_load_info), GFP_KERNEL);
		if(p->sysload == NULL) {
			kfree(p);
			return;
		}
		memcpy(p->sysload, sysload, sizeof(system_load_info));

		do_gettimeofday(&tm);
		p->timestamp = tm.tv_sec;

		p->prev = nlist_tail;
		p->next = NULL;
		nlist_tail->next = p;
		nlist_tail = p;
	}

	/* add a entry in the cluster information directory */
	if(create_file(p->host, &(p->dir)) < 0) {
		printk(KERN_ERR "Create new entry failed.\n");
//		exit(1);
	}
}

static void delete(struct node_entry* p)
{
	if(p == NULL)
		return;

	if(p == nlist_head) {
		nlist_head = p->next;
		if(p->next == NULL)
			nlist_tail = NULL;	/* only one entry */
		else
			p->next->prev = NULL;
		
	}else if(p == nlist_tail) {
		nlist_tail = p->prev;
		if(p->prev == NULL)
			nlist_head = NULL;	/* only one entry */
		else
			p->prev->next = NULL;

	}else {
		p->prev->next = p->next;
		p->next->prev = p->prev;

	}

	remove_file(p->host, p->dir); 

	kfree(p->sysload);
	kfree(p);
}

system_load_info* nlist_get(const char* host_ip)
{
	struct node_entry* p;

	p = nlist_head;

	nlist_lock();
	
	while(p != NULL) {
		if(strcmp(p->host, host_ip) == 0) {
			nlist_unlock();
			return p->sysload;
		}
		p = p->next;
	}

	nlist_unlock();

	return NULL;
}

/* update the node list */
void nlist_update(const char* host_ip, system_load_info* sysload)
{
	struct node_entry* p = nlist_head;
	struct timeval tm;

	nlist_lock();

	while(p != NULL) {
		if(strcmp(p->host, host_ip) == 0) {
			memcpy(p->sysload, sysload, sizeof(system_load_info));

			do_gettimeofday(&tm);
			p->timestamp = tm.tv_sec; /* last modified */

//			update_content(p->addr, p->sysload);

			nlist_unlock();
			return;
		}
		p = p->next;
	}

	/* this is a package from a new host */
	add(host_ip, sysload);

	nlist_unlock();
}

void nlist_check()
{
	struct node_entry* p;
	struct timeval tm;

	p = nlist_head;

	do_gettimeofday(&tm);

	nlist_lock();
	
	while(p != NULL) {
		if(tm.tv_sec - p->timestamp < OBSOLETE_INTERVAL) {
			p = p->next;
		}else {
			if(p->next == NULL) { /* this is the last host */
				delete(p);
				break;
			} else {
				p = p->next;
				delete(p->prev);	/* it is obsolete now. */
			}
		}
	}

	nlist_unlock();
}

void nlist_removeall()
{
	struct node_entry* p;
	p = nlist_head;

	nlist_lock();

	/* delete all nodes */
	while(p != NULL) {
		if(p->next == NULL) {
			delete(p);
			break;
		} else {
			p = p->next;
			delete(p->prev);
		}
	}

	nlist_unlock();
}