Initial commit

Author: topscoder

go.mod

@@ -0,0 +1,3 @@
+module github.com/topscoder/oldhost
+
+go 1.20

oldhost.go

@@ -0,0 +1,109 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"net/http"
+	"os"
+	"sync"
+	"time"
+)
+
+func main() {
+	ipsArg := flag.String("ips", "", "IPs (string or filename)")
+	hostsArg := flag.String("hosts", "", "Hosts (string or filename)")
+	silent := flag.Bool("silent", false, "Silent mode")
+	flag.Parse()
+
+	ips, err := readLines(*ipsArg)
+	if err != nil {
+		fmt.Println("Error reading IP addresses:", err)
+		return
+	}
+
+	hosts, err := readLines(*hostsArg)
+	if err != nil {
+		fmt.Println("Error reading hosts:", err)
+		return
+	}
+
+	client := http.Client{
+		Timeout: 1 * time.Second,
+	}
+
+	var wg sync.WaitGroup
+	semaphore := make(chan struct{}, 5) // Limit concurrent calls to 5
+
+	for _, ip := range ips {
+		for _, host := range hosts {
+			wg.Add(1)
+			go func(ip, host string) {
+				defer wg.Done()
+
+				semaphore <- struct{}{} // Acquire a slot from the semaphore
+				defer func() {
+					<-semaphore // Release the slot back to the semaphore
+				}()
+
+				url := fmt.Sprintf("http://%s", ip)
+				req, err := http.NewRequest("GET", url, nil)
+				if err != nil {
+					if !*silent {
+						fmt.Printf("Error creating request for IP %s and host %s: %s\n", ip, host, err)
+					}
+					return
+				}
+				req.Host = host
+
+				resp, err := client.Do(req)
+				if err != nil {
+					if !*silent {
+						fmt.Printf("Error making request for IP %s and host %s: %s\n", ip, host, err)
+					}
+					return
+				}
+				defer resp.Body.Close()
+
+				if *silent && resp.StatusCode != http.StatusOK {
+					return
+				}
+
+				if resp.StatusCode == http.StatusOK {
+					fmt.Printf("%s\t%s\n", ip, host)
+				}
+			}(ip, host)
+		}
+	}
+
+	wg.Wait()
+}
+
+func readLines(arg string) ([]string, error) {
+	lines := []string{}
+
+	if fileExists(arg) {
+		file, err := os.Open(arg)
+		if err != nil {
+			return lines, err
+		}
+		defer file.Close()
+
+		scanner := bufio.NewScanner(file)
+		for scanner.Scan() {
+			lines = append(lines, scanner.Text())
+		}
+	} else {
+		lines = append(lines, arg)
+	}
+
+	return lines, nil
+}
+
+func fileExists(path string) bool {
+	_, err := os.Stat(path)
+	if os.IsNotExist(err) {
+		return false
+	}
+	return err == nil
+}