util.c

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/*
 * Some small functions.
 *
 * Copyright (c) 2004, by:      Jian Shen
 *    All rights reserved.      Peking University, China
 *                             <[e-mail]>
 *
 * This file may be used subject to the terms and conditions of the
 * GNU Library General Public License Version 2, or any later version
 * at your option, as published by the Free Software Foundation.
 * 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 Library General Public License for more details.
 *
 */

#include "util.h"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <netdb.h>
#include <pwd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/select.h>
#include <netinet/in.h>
#include <arpa/inet.h>

/* get host's ip address by its alias according to /etc/hosts */
char* get_host_ip(const char* hostname)
{
	char* hostIP;
	struct hostent * h;
	struct in_addr* in;

	hostIP = (char*)malloc(20*sizeof(char));

	/* get host structure by host name */
	h = gethostbyname(hostname);
	if(h != NULL) {
		in = (struct in_addr*)h->h_addr;
		sprintf(hostIP,"%s", inet_ntoa(*in));

		return hostIP;			/* caller free */

	}else {
		fprintf(stderr, "gethostbyname failed.\n");
		return NULL;
	}
}

/* get current process's real user name */
char* get_user_name()
{
	uid_t uid;
	struct passwd* ppw;

	uid = getuid();
	ppw = getpwuid(uid);
	
	if( ppw == NULL)
		return NULL;
	else
		return ppw->pw_name;

}

int nonb_connect(int sockfd, struct sockaddr* sa, int sec)
{
	int flags;
	int status;
	fd_set mask;
	struct timeval timeout;

	flags = fcntl(sockfd, F_GETFL, 0);
	if(flags < 0)
		return -1;

	flags |= O_NONBLOCK;
	if(fcntl(sockfd, F_SETFL, flags) < 0) {
		perror("fcntl in nonb_connect");
		return -1;
	}

	if(connect(sockfd,sa,sizeof(struct sockaddr)) == 0) {
		flags &= ~O_NONBLOCK;
		fcntl(sockfd, F_SETFL, flags);
		return sockfd;
	}   

	FD_ZERO(&mask);
	FD_SET(sockfd,&mask);
	timeout.tv_sec = sec;
	timeout.tv_usec = 0;

	status = select(sockfd+1, NULL, &mask, NULL, &timeout);

	switch(status){
		case -1:
			perror("select");
			flags &= ~O_NONBLOCK;
			fcntl(sockfd, F_SETFL, flags);

			return -1;

		case 0:
			fprintf(stderr, "Connection Timeout.\n");
			flags &= ~O_NONBLOCK;
			fcntl(sockfd, F_SETFL, flags);

			return -2;

		default:
			FD_CLR(sockfd, &mask);
			flags &= ~O_NONBLOCK;
			fcntl(sockfd, F_SETFL, flags);

			return 0;
	}
}

void print_load(system_load_info* sysload)
{
	int i;
/* 	for(i=0; i<sysload->num_of_cpu; i++) { */
/* 		printf("CPU%d (%.3fMHZ): %.2f%s\n", i,  */
/* 				sysload->cpu_freq[i], sysload->cpu_util[i]*100, "%"); */
/* 	} */

/* 	printf("Total memory : %ld KB\n", sysload->total_mem); */
/* 	printf("Free memory : %ld KB\n", sysload->free_mem); */
/* 	printf("Load Avarage(1,5,15min) : %.2f %.2f %.2f\n",  */
/* 			sysload->loadavg[0], sysload->loadavg[1], sysload->loadavg[2]); */

	for(i=0; i<sysload->num_of_cpu; i++) {
		printf("CPU%d (%sMHZ): %s%s\n", i, 
				sysload->cpu_freq[i], sysload->cpu_util[i], "%");
	}

	printf("Total memory : %d KB\n", sysload->total_mem);
	printf("Free memory : %d KB\n", sysload->free_mem);
	printf("Load Avarage(1,5,15min) : %s %s %s\n", 
			sysload->loadavg[0], sysload->loadavg[1], sysload->loadavg[2]);

}

int xread(int sd, void *buf, size_t len)
{
	char *p = (char *)buf;
	size_t nrecv = 0;
	ssize_t rv;
	
	while (nrecv < len) {
		rv = read(sd, p, len - nrecv);
		if (rv < 0 && errno == EINTR)
			continue;
		if (rv < 0)
			return -1;
		if (rv == 0)
			return 0;			/* remote close the socket */
		nrecv += rv;
		p += rv;
	}
	return nrecv;
}