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authorJack Sangdahl <[email protected]>2024-04-02 23:09:23 -0600
committerJack Sangdahl <[email protected]>2024-04-02 23:09:23 -0600
commitf3172b837cc728dec1daa74ce98a72548f204b21 (patch)
treeb4fc78be5291b985145f93bbe7ca2607115234ba
parent6312e34a350ede7a73906792a8ff5d5efcf2f534 (diff)
downloadcsci3753-f3172b837cc728dec1daa74ce98a72548f204b21.tar.gz
csci3753-f3172b837cc728dec1daa74ce98a72548f204b21.zip
pa5
-rw-r--r--hostname_data/names1.txt23
-rw-r--r--hostname_data/names11.txt23
-rw-r--r--hostname_data/names12.txt20
-rw-r--r--hostname_data/names13.txt20
-rw-r--r--hostname_data/names14.txt20
-rw-r--r--hostname_data/names15.txt20
-rw-r--r--hostname_data/names2.txt20
-rw-r--r--hostname_data/names21.txt23
-rw-r--r--hostname_data/names22.txt20
-rw-r--r--hostname_data/names23.txt20
-rw-r--r--hostname_data/names24.txt20
-rw-r--r--hostname_data/names25.txt20
-rw-r--r--hostname_data/names3.txt20
-rw-r--r--hostname_data/names31.txt23
-rw-r--r--hostname_data/names32.txt20
-rw-r--r--hostname_data/names33.txt20
-rw-r--r--hostname_data/names34.txt20
-rw-r--r--hostname_data/names35.txt20
-rw-r--r--hostname_data/names4.txt20
-rw-r--r--hostname_data/names41.txt23
-rw-r--r--hostname_data/names42.txt20
-rw-r--r--hostname_data/names43.txt20
-rw-r--r--hostname_data/names44.txt20
-rw-r--r--hostname_data/names45.txt20
-rw-r--r--hostname_data/names5.txt20
-rw-r--r--hostname_data/names51.txt23
-rw-r--r--hostname_data/names52.txt20
-rw-r--r--hostname_data/names53.txt20
-rw-r--r--hostname_data/names54.txt20
-rw-r--r--hostname_data/names55.txt20
-rw-r--r--pa5_dns_resolver/Makefile8
-rw-r--r--pa5_dns_resolver/lookup.c71
-rw-r--r--pa5_dns_resolver/readme.md37
33 files changed, 734 insertions, 0 deletions
diff --git a/hostname_data/names1.txt b/hostname_data/names1.txt
new file mode 100644
index 0000000..d43eb9d
--- /dev/null
+++ b/hostname_data/names1.txt
@@ -0,0 +1,23 @@
+facebook.com
+youtube.com
+yahoo.com
+live.com
+wikipedia.org
+msn.com
+baidu.com
+blogspot.com
+microsoft.com
+qq.com
+taobao.com
+bing.com
+sina.com.cn
+soso.com
+163.com
+ask.com
+adobe.com
+twitter.com
+mozilla.com
+youku.com
+sdjjdsaf.com
+andysayler.com
+wmfo.org
diff --git a/hostname_data/names11.txt b/hostname_data/names11.txt
new file mode 100644
index 0000000..d43eb9d
--- /dev/null
+++ b/hostname_data/names11.txt
@@ -0,0 +1,23 @@
+facebook.com
+youtube.com
+yahoo.com
+live.com
+wikipedia.org
+msn.com
+baidu.com
+blogspot.com
+microsoft.com
+qq.com
+taobao.com
+bing.com
+sina.com.cn
+soso.com
+163.com
+ask.com
+adobe.com
+twitter.com
+mozilla.com
+youku.com
+sdjjdsaf.com
+andysayler.com
+wmfo.org
diff --git a/hostname_data/names12.txt b/hostname_data/names12.txt
new file mode 100644
index 0000000..89943e7
--- /dev/null
+++ b/hostname_data/names12.txt
@@ -0,0 +1,20 @@
+amazon.com
+wordpress.com
+tudou.com
+yahoo.co.jp
+sohu.com
+apple.com
+hao123.com
+windows.com
+ebay.com
+pps.tv
+xunlei.com
+56.com
+fc2.com
+paypal.com
+sogou.com
+tmall.com
+ku6.com
+rakuten.co.jp
+about.com
+orkut.com.br
diff --git a/hostname_data/names13.txt b/hostname_data/names13.txt
new file mode 100644
index 0000000..1ec9d3f
--- /dev/null
+++ b/hostname_data/names13.txt
@@ -0,0 +1,20 @@
+ifeng.com
+goo.ne.jp
+bbc.co.uk
+yandex.ru
+myspace.com
+mail.ru
+cnet.com
+go.com
+4399.com
+orkut.com
+skype.com
+ameblo.jp
+naver.com
+flickr.com
+4shared.com
+amazon.co.jp
+linkedin.com
+dailymotion.com
+imdb.com
+aol.com
diff --git a/hostname_data/names14.txt b/hostname_data/names14.txt
new file mode 100644
index 0000000..940a57c
--- /dev/null
+++ b/hostname_data/names14.txt
@@ -0,0 +1,20 @@
+hotmail.com
+360.cn
+craigslist.org
+weather.com
+soku.com
+alibaba.com
+megaupload.com
+renren.com
+livedoor.jp
+blogger.com
+vkontakte.ru
+answers.com
+rapidshare.com
+daum.net
+7k7k.com
+2345.com
+photobucket.com
+mediafire.com
+ehow.com
+seesaa.net
diff --git a/hostname_data/names15.txt b/hostname_data/names15.txt
new file mode 100644
index 0000000..e7f8366
--- /dev/null
+++ b/hostname_data/names15.txt
@@ -0,0 +1,20 @@
+paipai.com
+alipay.com
+softonic.com
+nifty.com
+imageshack.us
+cnn.com
+tianya.cn
+mywebsearch.com
+zynga.com
+partypoker.com
+hp.com
+walmart.com
+kugou.com
+ebay.de
+youdao.com
+hotfile.com
+qiyi.com
+pconline.com.cn
+odnoklassniki.ru
+jp.msn.com
diff --git a/hostname_data/names2.txt b/hostname_data/names2.txt
new file mode 100644
index 0000000..89943e7
--- /dev/null
+++ b/hostname_data/names2.txt
@@ -0,0 +1,20 @@
+amazon.com
+wordpress.com
+tudou.com
+yahoo.co.jp
+sohu.com
+apple.com
+hao123.com
+windows.com
+ebay.com
+pps.tv
+xunlei.com
+56.com
+fc2.com
+paypal.com
+sogou.com
+tmall.com
+ku6.com
+rakuten.co.jp
+about.com
+orkut.com.br
diff --git a/hostname_data/names21.txt b/hostname_data/names21.txt
new file mode 100644
index 0000000..d43eb9d
--- /dev/null
+++ b/hostname_data/names21.txt
@@ -0,0 +1,23 @@
+facebook.com
+youtube.com
+yahoo.com
+live.com
+wikipedia.org
+msn.com
+baidu.com
+blogspot.com
+microsoft.com
+qq.com
+taobao.com
+bing.com
+sina.com.cn
+soso.com
+163.com
+ask.com
+adobe.com
+twitter.com
+mozilla.com
+youku.com
+sdjjdsaf.com
+andysayler.com
+wmfo.org
diff --git a/hostname_data/names22.txt b/hostname_data/names22.txt
new file mode 100644
index 0000000..89943e7
--- /dev/null
+++ b/hostname_data/names22.txt
@@ -0,0 +1,20 @@
+amazon.com
+wordpress.com
+tudou.com
+yahoo.co.jp
+sohu.com
+apple.com
+hao123.com
+windows.com
+ebay.com
+pps.tv
+xunlei.com
+56.com
+fc2.com
+paypal.com
+sogou.com
+tmall.com
+ku6.com
+rakuten.co.jp
+about.com
+orkut.com.br
diff --git a/hostname_data/names23.txt b/hostname_data/names23.txt
new file mode 100644
index 0000000..1ec9d3f
--- /dev/null
+++ b/hostname_data/names23.txt
@@ -0,0 +1,20 @@
+ifeng.com
+goo.ne.jp
+bbc.co.uk
+yandex.ru
+myspace.com
+mail.ru
+cnet.com
+go.com
+4399.com
+orkut.com
+skype.com
+ameblo.jp
+naver.com
+flickr.com
+4shared.com
+amazon.co.jp
+linkedin.com
+dailymotion.com
+imdb.com
+aol.com
diff --git a/hostname_data/names24.txt b/hostname_data/names24.txt
new file mode 100644
index 0000000..940a57c
--- /dev/null
+++ b/hostname_data/names24.txt
@@ -0,0 +1,20 @@
+hotmail.com
+360.cn
+craigslist.org
+weather.com
+soku.com
+alibaba.com
+megaupload.com
+renren.com
+livedoor.jp
+blogger.com
+vkontakte.ru
+answers.com
+rapidshare.com
+daum.net
+7k7k.com
+2345.com
+photobucket.com
+mediafire.com
+ehow.com
+seesaa.net
diff --git a/hostname_data/names25.txt b/hostname_data/names25.txt
new file mode 100644
index 0000000..e7f8366
--- /dev/null
+++ b/hostname_data/names25.txt
@@ -0,0 +1,20 @@
+paipai.com
+alipay.com
+softonic.com
+nifty.com
+imageshack.us
+cnn.com
+tianya.cn
+mywebsearch.com
+zynga.com
+partypoker.com
+hp.com
+walmart.com
+kugou.com
+ebay.de
+youdao.com
+hotfile.com
+qiyi.com
+pconline.com.cn
+odnoklassniki.ru
+jp.msn.com
diff --git a/hostname_data/names3.txt b/hostname_data/names3.txt
new file mode 100644
index 0000000..1ec9d3f
--- /dev/null
+++ b/hostname_data/names3.txt
@@ -0,0 +1,20 @@
+ifeng.com
+goo.ne.jp
+bbc.co.uk
+yandex.ru
+myspace.com
+mail.ru
+cnet.com
+go.com
+4399.com
+orkut.com
+skype.com
+ameblo.jp
+naver.com
+flickr.com
+4shared.com
+amazon.co.jp
+linkedin.com
+dailymotion.com
+imdb.com
+aol.com
diff --git a/hostname_data/names31.txt b/hostname_data/names31.txt
new file mode 100644
index 0000000..d43eb9d
--- /dev/null
+++ b/hostname_data/names31.txt
@@ -0,0 +1,23 @@
+facebook.com
+youtube.com
+yahoo.com
+live.com
+wikipedia.org
+msn.com
+baidu.com
+blogspot.com
+microsoft.com
+qq.com
+taobao.com
+bing.com
+sina.com.cn
+soso.com
+163.com
+ask.com
+adobe.com
+twitter.com
+mozilla.com
+youku.com
+sdjjdsaf.com
+andysayler.com
+wmfo.org
diff --git a/hostname_data/names32.txt b/hostname_data/names32.txt
new file mode 100644
index 0000000..89943e7
--- /dev/null
+++ b/hostname_data/names32.txt
@@ -0,0 +1,20 @@
+amazon.com
+wordpress.com
+tudou.com
+yahoo.co.jp
+sohu.com
+apple.com
+hao123.com
+windows.com
+ebay.com
+pps.tv
+xunlei.com
+56.com
+fc2.com
+paypal.com
+sogou.com
+tmall.com
+ku6.com
+rakuten.co.jp
+about.com
+orkut.com.br
diff --git a/hostname_data/names33.txt b/hostname_data/names33.txt
new file mode 100644
index 0000000..1ec9d3f
--- /dev/null
+++ b/hostname_data/names33.txt
@@ -0,0 +1,20 @@
+ifeng.com
+goo.ne.jp
+bbc.co.uk
+yandex.ru
+myspace.com
+mail.ru
+cnet.com
+go.com
+4399.com
+orkut.com
+skype.com
+ameblo.jp
+naver.com
+flickr.com
+4shared.com
+amazon.co.jp
+linkedin.com
+dailymotion.com
+imdb.com
+aol.com
diff --git a/hostname_data/names34.txt b/hostname_data/names34.txt
new file mode 100644
index 0000000..940a57c
--- /dev/null
+++ b/hostname_data/names34.txt
@@ -0,0 +1,20 @@
+hotmail.com
+360.cn
+craigslist.org
+weather.com
+soku.com
+alibaba.com
+megaupload.com
+renren.com
+livedoor.jp
+blogger.com
+vkontakte.ru
+answers.com
+rapidshare.com
+daum.net
+7k7k.com
+2345.com
+photobucket.com
+mediafire.com
+ehow.com
+seesaa.net
diff --git a/hostname_data/names35.txt b/hostname_data/names35.txt
new file mode 100644
index 0000000..e7f8366
--- /dev/null
+++ b/hostname_data/names35.txt
@@ -0,0 +1,20 @@
+paipai.com
+alipay.com
+softonic.com
+nifty.com
+imageshack.us
+cnn.com
+tianya.cn
+mywebsearch.com
+zynga.com
+partypoker.com
+hp.com
+walmart.com
+kugou.com
+ebay.de
+youdao.com
+hotfile.com
+qiyi.com
+pconline.com.cn
+odnoklassniki.ru
+jp.msn.com
diff --git a/hostname_data/names4.txt b/hostname_data/names4.txt
new file mode 100644
index 0000000..940a57c
--- /dev/null
+++ b/hostname_data/names4.txt
@@ -0,0 +1,20 @@
+hotmail.com
+360.cn
+craigslist.org
+weather.com
+soku.com
+alibaba.com
+megaupload.com
+renren.com
+livedoor.jp
+blogger.com
+vkontakte.ru
+answers.com
+rapidshare.com
+daum.net
+7k7k.com
+2345.com
+photobucket.com
+mediafire.com
+ehow.com
+seesaa.net
diff --git a/hostname_data/names41.txt b/hostname_data/names41.txt
new file mode 100644
index 0000000..d43eb9d
--- /dev/null
+++ b/hostname_data/names41.txt
@@ -0,0 +1,23 @@
+facebook.com
+youtube.com
+yahoo.com
+live.com
+wikipedia.org
+msn.com
+baidu.com
+blogspot.com
+microsoft.com
+qq.com
+taobao.com
+bing.com
+sina.com.cn
+soso.com
+163.com
+ask.com
+adobe.com
+twitter.com
+mozilla.com
+youku.com
+sdjjdsaf.com
+andysayler.com
+wmfo.org
diff --git a/hostname_data/names42.txt b/hostname_data/names42.txt
new file mode 100644
index 0000000..89943e7
--- /dev/null
+++ b/hostname_data/names42.txt
@@ -0,0 +1,20 @@
+amazon.com
+wordpress.com
+tudou.com
+yahoo.co.jp
+sohu.com
+apple.com
+hao123.com
+windows.com
+ebay.com
+pps.tv
+xunlei.com
+56.com
+fc2.com
+paypal.com
+sogou.com
+tmall.com
+ku6.com
+rakuten.co.jp
+about.com
+orkut.com.br
diff --git a/hostname_data/names43.txt b/hostname_data/names43.txt
new file mode 100644
index 0000000..1ec9d3f
--- /dev/null
+++ b/hostname_data/names43.txt
@@ -0,0 +1,20 @@
+ifeng.com
+goo.ne.jp
+bbc.co.uk
+yandex.ru
+myspace.com
+mail.ru
+cnet.com
+go.com
+4399.com
+orkut.com
+skype.com
+ameblo.jp
+naver.com
+flickr.com
+4shared.com
+amazon.co.jp
+linkedin.com
+dailymotion.com
+imdb.com
+aol.com
diff --git a/hostname_data/names44.txt b/hostname_data/names44.txt
new file mode 100644
index 0000000..940a57c
--- /dev/null
+++ b/hostname_data/names44.txt
@@ -0,0 +1,20 @@
+hotmail.com
+360.cn
+craigslist.org
+weather.com
+soku.com
+alibaba.com
+megaupload.com
+renren.com
+livedoor.jp
+blogger.com
+vkontakte.ru
+answers.com
+rapidshare.com
+daum.net
+7k7k.com
+2345.com
+photobucket.com
+mediafire.com
+ehow.com
+seesaa.net
diff --git a/hostname_data/names45.txt b/hostname_data/names45.txt
new file mode 100644
index 0000000..e7f8366
--- /dev/null
+++ b/hostname_data/names45.txt
@@ -0,0 +1,20 @@
+paipai.com
+alipay.com
+softonic.com
+nifty.com
+imageshack.us
+cnn.com
+tianya.cn
+mywebsearch.com
+zynga.com
+partypoker.com
+hp.com
+walmart.com
+kugou.com
+ebay.de
+youdao.com
+hotfile.com
+qiyi.com
+pconline.com.cn
+odnoklassniki.ru
+jp.msn.com
diff --git a/hostname_data/names5.txt b/hostname_data/names5.txt
new file mode 100644
index 0000000..e7f8366
--- /dev/null
+++ b/hostname_data/names5.txt
@@ -0,0 +1,20 @@
+paipai.com
+alipay.com
+softonic.com
+nifty.com
+imageshack.us
+cnn.com
+tianya.cn
+mywebsearch.com
+zynga.com
+partypoker.com
+hp.com
+walmart.com
+kugou.com
+ebay.de
+youdao.com
+hotfile.com
+qiyi.com
+pconline.com.cn
+odnoklassniki.ru
+jp.msn.com
diff --git a/hostname_data/names51.txt b/hostname_data/names51.txt
new file mode 100644
index 0000000..d43eb9d
--- /dev/null
+++ b/hostname_data/names51.txt
@@ -0,0 +1,23 @@
+facebook.com
+youtube.com
+yahoo.com
+live.com
+wikipedia.org
+msn.com
+baidu.com
+blogspot.com
+microsoft.com
+qq.com
+taobao.com
+bing.com
+sina.com.cn
+soso.com
+163.com
+ask.com
+adobe.com
+twitter.com
+mozilla.com
+youku.com
+sdjjdsaf.com
+andysayler.com
+wmfo.org
diff --git a/hostname_data/names52.txt b/hostname_data/names52.txt
new file mode 100644
index 0000000..89943e7
--- /dev/null
+++ b/hostname_data/names52.txt
@@ -0,0 +1,20 @@
+amazon.com
+wordpress.com
+tudou.com
+yahoo.co.jp
+sohu.com
+apple.com
+hao123.com
+windows.com
+ebay.com
+pps.tv
+xunlei.com
+56.com
+fc2.com
+paypal.com
+sogou.com
+tmall.com
+ku6.com
+rakuten.co.jp
+about.com
+orkut.com.br
diff --git a/hostname_data/names53.txt b/hostname_data/names53.txt
new file mode 100644
index 0000000..1ec9d3f
--- /dev/null
+++ b/hostname_data/names53.txt
@@ -0,0 +1,20 @@
+ifeng.com
+goo.ne.jp
+bbc.co.uk
+yandex.ru
+myspace.com
+mail.ru
+cnet.com
+go.com
+4399.com
+orkut.com
+skype.com
+ameblo.jp
+naver.com
+flickr.com
+4shared.com
+amazon.co.jp
+linkedin.com
+dailymotion.com
+imdb.com
+aol.com
diff --git a/hostname_data/names54.txt b/hostname_data/names54.txt
new file mode 100644
index 0000000..940a57c
--- /dev/null
+++ b/hostname_data/names54.txt
@@ -0,0 +1,20 @@
+hotmail.com
+360.cn
+craigslist.org
+weather.com
+soku.com
+alibaba.com
+megaupload.com
+renren.com
+livedoor.jp
+blogger.com
+vkontakte.ru
+answers.com
+rapidshare.com
+daum.net
+7k7k.com
+2345.com
+photobucket.com
+mediafire.com
+ehow.com
+seesaa.net
diff --git a/hostname_data/names55.txt b/hostname_data/names55.txt
new file mode 100644
index 0000000..e7f8366
--- /dev/null
+++ b/hostname_data/names55.txt
@@ -0,0 +1,20 @@
+paipai.com
+alipay.com
+softonic.com
+nifty.com
+imageshack.us
+cnn.com
+tianya.cn
+mywebsearch.com
+zynga.com
+partypoker.com
+hp.com
+walmart.com
+kugou.com
+ebay.de
+youdao.com
+hotfile.com
+qiyi.com
+pconline.com.cn
+odnoklassniki.ru
+jp.msn.com
diff --git a/pa5_dns_resolver/Makefile b/pa5_dns_resolver/Makefile
new file mode 100644
index 0000000..d256f8e
--- /dev/null
+++ b/pa5_dns_resolver/Makefile
@@ -0,0 +1,8 @@
+OBJS = lookup.o
+CFLAGS = -Wall
+
+all: $(OBJS)
+ cc $(CFLAGS) -o lookup $(OBJS)
+
+clean:
+ rm *.o *lookup hostnames.log
diff --git a/pa5_dns_resolver/lookup.c b/pa5_dns_resolver/lookup.c
new file mode 100644
index 0000000..5b8e4cd
--- /dev/null
+++ b/pa5_dns_resolver/lookup.c
@@ -0,0 +1,71 @@
+// Jack Sangdahl
+// CSCI3753 SP24
+// PA5 DNS infoolver
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#define MAX_NAME_LENGTH 16 // longest string in data/
+#define MAX_NAME_COUNT 24 // longest file by lines in data/
+struct addrinfo hints;
+
+char *domain_ip(char *domain) {
+ char *res = (char *)malloc(sizeof(char) * INET_ADDRSTRLEN);
+ struct addrinfo *info, *i;
+ if (getaddrinfo(domain, NULL, &hints, &info))
+ return (char *)"NOT_RESOLVED";
+ for (i = info; i != NULL; i = i->ai_next) {
+ struct sockaddr_in *ipv4 = (struct sockaddr_in *)i->ai_addr;
+ char ipstr[INET_ADDRSTRLEN]; // INET_ADDRSTRLEN translates to 16
+ inet_ntop(AF_INET, &(ipv4->sin_addr), ipstr, INET_ADDRSTRLEN);
+ strcpy(res, ipstr);
+ break;
+ }
+ freeaddrinfo(info);
+ return res;
+}
+
+int main(int argc, char **argv) {
+ if (argc < 3) {
+ fprintf(stdout, "usage: %s <log_file> [ <datafile> ...]\n", argv[0]);
+ return EXIT_FAILURE;
+ }
+ struct timeval begin, end;
+ gettimeofday(&begin, NULL);
+ if (!memset(&hints, 0, sizeof(hints))) {
+ fprintf(stderr, "ERROR: memset failed\n");
+ return EXIT_FAILURE;
+ }
+ hints.ai_family = AF_INET; // limit to only ipv4
+ hints.ai_socktype = SOCK_STREAM; // limit to tcp ports
+ FILE *log_file = fopen(argv[1], "w");
+ for (uint8_t i = 1; i < argc; i++) {
+ FILE *data_file = fopen(argv[i], "r");
+ if (!data_file) {
+ fprintf(stdout, "ERROR: %s\n", strerror(errno));
+ return EXIT_FAILURE;
+ }
+ char buffer[MAX_NAME_LENGTH];
+ char **hostnames = (char **)malloc(sizeof(char *) * MAX_NAME_COUNT);
+ uint8_t name_cnt = 0;
+ while (fgets(buffer, sizeof(buffer), data_file)) {
+ hostnames[name_cnt] = (char *)malloc(sizeof(char) * (strlen(buffer) + 1));
+ buffer[strcspn(buffer, "\n")] = 0;
+ strcpy(hostnames[name_cnt], buffer);
+ name_cnt++;
+ }
+ for (uint8_t i = 0; i < name_cnt; i++)
+ fprintf(log_file, "%s, %s\n", hostnames[i], domain_ip(hostnames[i]));
+ free(hostnames);
+ fclose(data_file);
+ }
+ fclose(log_file);
+ gettimeofday(&end, NULL);
+ double runtime = (double)(end.tv_usec - begin.tv_usec) / 1000000 +
+ (double)(end.tv_sec - begin.tv_sec);
+ fprintf(stdout, "%s: total time is %f seconds\n", argv[0], runtime);
+ return EXIT_SUCCESS;
+}
diff --git a/pa5_dns_resolver/readme.md b/pa5_dns_resolver/readme.md
new file mode 100644
index 0000000..c213c9b
--- /dev/null
+++ b/pa5_dns_resolver/readme.md
@@ -0,0 +1,37 @@
+## PA5 - DNS Resolver
+### overview
+this assignment will develop an application that resolves domain names
+to ip addresses. this is similar to the operation performed each time
+you access a new website in your browser. provided are a set of input
+files that contain one hostname per line. your program will process each
+of these files by reading the file line by line, look up the ip address
+for that hostname, and then write the hostname and ip address to the
+specified log file using the following format:
+```
+google.com, 74.125.224.81
+```
+if the resolved is unable to fid the ip address for a hostname, it
+should leave `NOT_RESOLVED` instead of an ip address. the program must
+end after all names in each input file have been serviced by the
+application. prior to exiting, the program should print the total time
+taken to stdout
+```
+./lookup: total time is 2.420237 seconds
+```
+`gettimeofday()` library function is recommended for this purpose.
+
+### error handling
+program should deal with the following conditions
+* missing arguments - terminate with a usage synopsis to stdout
+* arguments that are out of range (ie. too many input files) should
+terminate with an error message to stderr
+* if a log file exists and is writeable, it should be overwritten
+* if a log file does not exist, it should be created by the program
+* missing or unreadable input files should print `invalid file <filename>`
+to stderr, then move onto next file
+
+all system and library calls should be checked for errors. if you
+encounter errors not listed above, you should print an appropriate
+message to stderr, and then either exit or continue depending up
+whether or not you can recover from the error gracefully. make sure
+your program returns an appropriate exit status.