From 9ae20db92e378c2ecd797350655a9bc2c946b1cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Busse?= <bj.rn@baerlin.eu>
Date: Mon, 2 Oct 2017 10:43:44 +0000
Subject: [PATCH] Initial commit

---
 main.go | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 main.go

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..4f432e3
--- /dev/null
+++ b/main.go
@@ -0,0 +1,107 @@
+package main
+
+import (
+	"container/ring"
+	"fmt"
+	"github.com/hpcloud/tail"
+	"encoding/json"
+	"net/http"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func fileHandler(w http.ResponseWriter, r *http.Request, s string) {
+    fn := r.URL.Path[5:len(r.URL.Path)]
+
+    for _, v := range whitelist {
+        if !strings.Contains(v, fn) {
+            sendFile(w, fn, "", "Permission denied")
+	    return
+        }
+    }
+
+    if _, err := os.Stat(fn); err != nil {
+       sendFile(w, fn, "", "No such file or directory")
+       return
+    }
+
+    if (watch == false) {
+        t, err := tail.TailFile(fn, tail.Config{Follow: false})
+	watch = true
+    }
+
+    if (err == nil) {
+       fmt.Println(err)
+    }
+
+    var m = ""
+
+    w.WriteHeader(http.StatusOK)
+    for line := range t.Lines {
+        m += fmt.Sprintf("%s\n", line.Text)
+        logring.Value = line.Text
+        logring = logring.Next()
+    }
+    if m != m_prev {
+        sendFile(w, fn, m, "")
+        m_prev = m
+    }
+}
+
+func sendFile(w http.ResponseWriter, fn string, m string, err string) {
+    json.NewEncoder(w).Encode(map[string]string{"time": strconv.FormatInt(t_ms(), 16), "Filename": fn, "Text": m, "error": err})
+}
+
+func t_ms() (int64) {
+    now := time.Now()
+    ns := now.UnixNano()
+    ms := ns / 1000000
+    return ms
+}
+
+func makeHandler(fn func(http.ResponseWriter, *http.Request, string)) http.HandlerFunc {
+    return func(w http.ResponseWriter, r *http.Request) {
+        m := validPath.FindStringSubmatch(r.URL.Path)
+        if m == nil {
+            http.NotFound(w, r)
+            return
+        }
+        fmt.Println("makeHandler::request::" + r.RequestURI)
+        fn(w, r, m[2])
+    }
+}
+
+var prj = "httptail"
+var version = "0.1.0"
+var server_inet6 = "[fdef:c181:4234:7978:6::1]:8080"
+var whitelist = map[int]string{
+	0: "/var/log",
+}
+
+var logring = ring.New(1000)
+var validPath = regexp.MustCompile("^/(tail*|auth)/(.*)$")
+var watch bool = false
+var m_prev = ""
+
+func main() {
+	uid := os.Getuid()
+	t.Filename = ""
+
+	if (uid == -1) {
+	    fmt.Println("Windows is unsupported")
+        }
+
+	if (uid == 0) {
+            fmt.Println("Refusing to run as root")
+	    return
+	}
+
+	http.HandleFunc("/tail/", makeHandler(fileHandler))
+
+        fmt.Println("Serving " + prj + " " + version + " on " + server_inet6)
+        http.ListenAndServe(server_inet6, nil)
+	t.Cleanup()
+}