gistfile1.c

/*
 * tlook.c - [email protected] based on mlook.c
 * threaded mass resolver
 * 
 * ./tlook <file> Accepts stdin if no arguments are given resolves both hostname
 * and IPs
 * 
 * grep new.cgi access.log | awk '{print $1}' | sort |uniq |tlook > resolved
 * 
 */

/*
 * TODO: rewrite using reentrant versions of appropriate functions, rather
 * than with mutex locking (should improve performance)
 */

#include <stdio.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <pthread.h>

#define MAXCHILD 200

char            buffers[MAXCHILD][1024];
pthread_mutex_t mutex_IP;
pthread_mutex_t mutex_HOST;

void           *
lookitup(void *tid)
{
	char            ipstr[1024];
	struct in_addr  ip;
	struct hostent *he;
	int             tnid = *((int *)(tid));

	strncpy(ipstr, buffers[tnid], sizeof(ipstr) - 1);

	if ((ip.s_addr = inet_addr(ipstr)) == -1) {
		if ((he = gethostbyname(ipstr)) == NULL) {
			printf("%s   ->   invalid\n", ipstr);
		} else {
			pthread_mutex_lock(&mutex_IP);
			memcpy(&ip.s_addr, he->h_addr, he->h_length);
			printf("%s   ->   %s\n", ipstr, inet_ntoa(ip));
			pthread_mutex_unlock(&mutex_IP);
		}

	} else {
		pthread_mutex_lock(&mutex_HOST);
		if ((he = gethostbyaddr((char *)&ip, sizeof(ip), AF_INET)) == NULL) {
			printf("%s   ->   N/A\n", ipstr);

		} else
			printf("%s   ->   %s\n", ipstr, he->h_name);
		pthread_mutex_unlock(&mutex_HOST);
	}
	pthread_exit((void *)0);
}

int 
main(int argc, char *argv[])
{
	int             mchild = MAXCHILD, children = 0, i;
	char            buffer[1024];
	FILE           *fh;
	pthread_t       threads[MAXCHILD];
	pthread_attr_t  attr;
	int             rc, status;
	int            *taskids[MAXCHILD];

	pthread_mutex_init(&mutex_IP, NULL);
	pthread_mutex_init(&mutex_HOST, NULL);
	pthread_attr_init(&attr);
	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
	if (argc < 2) {
		fh = stdin;
	} else if ((fh = fopen(argv[1], "r")) == NULL) {
		printf("file not found: %s\n", argv[1]);
		exit(-1);
	}
	while (fgets(buffer, sizeof(buffer), fh) != NULL) {
		for (i = 0; i < strlen(buffer); i++) {
			if (buffer[i] == '\n') {
				memset(&buffer[i], 0, 1);
			}
		}
		taskids[children] = (int *)malloc(sizeof(int));
		*taskids[children] = children;
		strncpy(buffers[children], buffer, sizeof(buffers[children]) - 1);
		rc = pthread_create(&threads[children], &attr, lookitup, (void *)taskids[children]);
		children++;
		if (children == MAXCHILD) {
			for (children = 0; children < MAXCHILD; children++) {
				pthread_join(threads[children], (void **)&status);
			}
			children = 0;
		}
	}
	for (i = 0; i < children; i++) {
		pthread_join(threads[i], (void **)&status);
	}
	pthread_mutex_destroy(&mutex_IP);
	pthread_mutex_destroy(&mutex_HOST);
	pthread_exit(NULL);
	return 0;
}