Commit: 6550af1b2f12d5c0870c067710d4cca4c43f62a6
Parent: 684cc056787857ec61d9abebeaabdba776b4f6d4
Author: Vi Grey
Date: 2023-11-21 06:35 UTC
Summary: Add article and simplify repo for tmp.0ut vol 3

 .gitignore                     |   3 +
 31.txt                         |  78 ++++++++++++++++++++
 README.txt                     |  25 -------
 gopher-server.go               | 199 --------------------------------------------------
 gopher-server/gen-polyglot.sh  |  40 ++++++++++
 go.mod => gopher-server/go.mod |   0
 gopher-server/gopher-server.go | 313 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 index.gph                      |   6 --
 index.gph-example              |  20 -----
 polyglot-instructions.txt      |  38 ----------
 10 files changed, 434 insertions(+), 288 deletions(-)


diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a9c8fd3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+gopher-server/gopher-server
+gopher-server/cat.zip
+gopher-server/gopher-server-zip-polyglot.zip
diff --git a/31.txt b/31.txt
new file mode 100644
index 0000000..26cd37b
--- /dev/null
+++ b/31.txt
@@ -0,0 +1,78 @@
+
+          ████▓░░░░█░░░░░░░░░░█░░░█ 
+        █░██░░███░░░░█████░░░░░███░█
+        ░░░█░░  █░░░░░ ░█░█░░░░██░▒ 
+         ██░░ ███░░░░ ████░░░░░█    
+          █░▓ ▒██░░░█ █ ██░░░░░█    
+       ██░░█░░░░█░░▒█░░░░░█▒░░░█    
+     █░░░░░░░░░█ █  █░░░░░░░░░░░░█  
+    ▒░░░░░░░░░░░▒██▒█░░░░░░░░░█░░░█ 
+    █░░██░░░░░░░░█░░░░░░░░░░▓░░░░░█ 
+    ▓░░░░░▒███▓▒████░░░░██▒░░░░░░░█ 
+    ██░░░░░░█    █     ██░░░░░░░░░█ 
+    ██░░░░░░█    █     █░░░░░░░░░█▓ 
+      █░░░░░░█   ▓     █░░░░░░░░█   
+        █░░░░░░░░░░░░░░░░░░░░░█     
+          █░░░░░░░░░░░░░░░██        
+              ██░░░░░░█             
+                  ██                
+
+Long Live Gopher! This Zine Is Also A Gopher Server
+~Vi Grey
+-----------------------------------------------------------------------
+
+I was asked only a little bit before the release of this issue if I
+wanted to help make the ZIP file release of this issue a polyglot file.
+
+Making polyglot files where one part of the file is a ZIP file tends to
+be pretty simple.  Basically concatenate a file with the ZIP file to
+make a third file and adjust the ZIP file offsets in that third file so
+the ZIP file part works without throwing any errors.  The only problem
+though is that's pretty boring.  It's more fun to make sure the ZIP file
+part is as important to the polyglot file as anything else!
+
+My solution was making a Gopher Server (gopherhole) that can serve the
+content of the ZIP file.  There's already an HTTP version of the zine,
+so why not add a Gopher version?  Besides, I'm a Minnesotan and feel
+like I should rep the big competitor to the World Wide Web that came
+from this state, even if the University messed it all up by trying to
+monetize it...
+
+On Linux x86_64, you can make this ZIP file executable with `chmod +x`
+and run the file in a terminal.  It will start a Gopher Server at
+gopher://localhost:2311 (2311 was chosen because this zine issue's
+release date is in 2023-11) which can be visited with your gopher client
+of choice.
+
+If you want to use a different address or different port, you can use
+the flag options --host <name> and --port <num>, for instance
+`--host mappedhost --port 9070` if you wanted the gopherhole to listen
+at gopher://mappedhost:9070 instead of gopher:localhost:2311.  You can
+also specify a ZIP file instead of using the executable as the ZIP file
+by using the --zip <path> flag option, for instance `--zip test.zip` if
+you want the gopherhole to serve content from test.zip.
+
+If you want to make the ZIP file of this issue a Gopher server for your
+system, I have included the gopher-server source code and a shell
+script called `gen-polyglot.sh` to generate the polyglot file.  Just be
+sure to edit the goos and goarch variables in the shell script with the
+correct OS and architecture settings for your computer.  To use
+gen-polyglot.sh, you can run:
+
+```
+./gen-polyglot.sh /path/to/tmp.0ut.3.txt.zip
+```
+
+where `/path/to/tmp.0ut.3.txt.zip` is the path to the tmp.0ut volume 3
+ZIP file.
+
+The dependencies to compile the go-server source code and create the
+polyglot file are:
+- go >= 1.15
+- zip
+
+File List:
+gopher-server
+├── gen-polyglot.sh
+├── go.mod
+└── gopher-server.go
diff --git a/README.txt b/README.txt
deleted file mode 100644
index 6e8dcdc..0000000
--- a/README.txt
+++ /dev/null
@@ -1,25 +0,0 @@
-Gopher Server
---------------
-
-A gopher server for an executable+ZIP polyglot file that hosts the
-content in the ZIP file portion of the polyglot file.
-
-Instructions to produce the polyglot file are included in the file
-`polyglot-instructions.txt`.
-
-An `index.gph` file is included.  It is incredibly important that the
-tabs and the first character of each line be correct, as gophermap
-files are quite picky.  An example index gophermap file is included at
-`index.gph-example`, which is a gophermap for the tmp.0ut zine for
-Volume 1.
-
-The gopher server is expecting an index.gph file at the root of the
-ZIP file.
-
-Upon running the server, the Gopherhole will be listening at TCP
-"localhost:2311" unless specified using the --host and/or --port flag
-arguments.  For more details, you can run the server with -h or --help.
-
-Port 2311 was chosen for the 2023-11 release of tmp.0ut Volume 3 and
-because it's an unprivileged port, unlike port 70, which is used by
-default for Gopherholes.
diff --git a/gopher-server.go b/gopher-server.go
deleted file mode 100644
index 45a6ee4..0000000
--- a/gopher-server.go
+++ /dev/null
@@ -1,199 +0,0 @@
-/*
- +------------------------+
- |     Gopher Server      |
- | Programmed by Vi Grey  |
- +------------------------+
-
- This is meant to be compiled and prepended to a ZIP file to make it an
- Executable+ZIP polyglot file with the intention of the ZIP file
- hosting the content for the Gopherhole.  Please make sure an
- "index.gph" gophermap file is included in the root of the ZIP file.
- If run without any arguments, the ZIP file will be the executable
- itself, and the Gopherhole will be listening on localhost:2311 (2311
- chosen because 2023-11 for the release of tmp.0ut Volume 3)
-
- Do whatever the heck you want to with this code, just don't blame me
- if anything happens...
-
- GO GOLDEN GOPHERS!
-*/
-
-package main
-
-import (
-	"archive/zip"
-	"fmt"
-	"io"
-	"log"
-	"net"
-	"os"
-	"path/filepath"
-	"strconv"
-	"strings"
-	"time"
-)
-
-var (
-	port        = 2311
-	host        = "localhost"
-	zipFilePath string
-	zipReader   *zip.ReadCloser
-)
-
-// Print error log and close program with error code 1 if err not nil
-func handleErr(err error) {
-	if err != nil {
-		log.Fatalf("%s\nExiting...\n", err)
-	}
-}
-
-// Open ZIP file and get Reader
-func getZIPFileReader() {
-	var err error
-	zipReader, err = zip.OpenReader(zipFilePath)
-	handleErr(err)
-}
-
-// Get request from gopher client and serve page from ZIP file if path
-// exists inside of ZIP file
-func handleGopherConnection(conn net.Conn) {
-	var rBuf []byte
-	var request string
-	// Continue reading from connection until first \r\n is found
-	for {
-		rBuf = make([]byte, 2048)
-		n, err := conn.Read(rBuf)
-		if err != nil || n == 0 {
-			break
-		}
-		request += string(rBuf[:n])
-		// Gopher path request ends at first instance of \r\n
-		nlIndex := strings.Index(request, "\r\n")
-		if nlIndex > -1 {
-			reqPath := request[:nlIndex] // Gopher path request
-			if reqPath == "" || reqPath == "/" {
-				// Set path to index.gph if request is root path
-				reqPath = "index.gph"
-			}
-			for _, zipFile := range zipReader.File {
-				if filepath.Join("/", reqPath) == filepath.Join("/", zipFile.Name) {
-					// /reqPath is in zip directory root
-					f, err := zipFile.Open()
-					handleErr(err)
-					defer f.Close()
-					// Write file content from zip file to connection
-					io.Copy(conn, f)
-					conn.Write([]byte("\r\n.\r\n"))
-					return
-				}
-			}
-			// Send error to gopher client.  Essentially the same as HTTP 404
-			conn.Write([]byte("3The selected resource does not exist\t\t" +
-				"fake\tfake\t0\r\n.\r\n"))
-			return
-		}
-	}
-	// Send error to gopher client.  Essentially the same as HTTP 400
-	conn.Write([]byte("3Invalid Request\t\tfake\tfake\t0\r\n.\r\n"))
-}
-
-// Start the gopher server at specified host and port (default
-// localhost:2311)
-func startGopherServer() {
-	listener, err := net.Listen("tcp",
-		fmt.Sprintf("%s:%d", host, port))
-	handleErr(err)
-	for {
-		if conn, err := listener.Accept(); err == nil {
-			go func() {
-				defer conn.Close()
-				// Close connection when request handled or after 30 seconds
-				conn.SetReadDeadline(time.Now().Add(30 * time.Second))
-				handleGopherConnection(conn)
-			}()
-		}
-	}
-}
-
-// Display help message and close program
-func displayHelp() {
-	fmt.Printf(`Usage %s [OPTIONS]...
-
-Options:
-  -h, --help              Print Help (this message) and exit
-      --host <name>       TCP address for gopher server to listen on
-                          (default: "localhost")
-      --port <num>        TCP port to listen on (default: 2311)
-      --zip <path>        Path to ZIP file that hosts the content
-                          (default: this executable file itself)
-`, os.Args[0])
-}
-
-// Get a string value from args[x+1]
-func getFlagStrValue(args []string, x, argsLen int) (string, error) {
-	if x+1 >= argsLen {
-		err := fmt.Errorf("%s: flag `%s` missing value\n Use `%s --help` for "+
-			"details", os.Args[0], args[x], os.Args[0])
-		return "", err
-	}
-	return args[x+1], nil
-}
-
-// Get an integer value of 1-65535 from args[x+1]
-func getFlagPortValue(args []string, x, argsLen int) (int, error) {
-	strVal, err := getFlagStrValue(args, x, argsLen)
-	if err != nil {
-		return 0, err
-	}
-	portVal, _ := strconv.Atoi(strVal)
-	if portVal < 1 || portVal > 65535 {
-		err = fmt.Errorf("%s: flag `%s` value must be a number value of "+
-			"1-65535\nUse `%s --help` for details",
-			os.Args[0], args[x], os.Args[0])
-		return 0, err
-	}
-	return portVal, nil
-}
-
-func init() {
-	var err error
-	// Get executable path in case --zip flag not used
-	zipFilePath, err = os.Executable()
-	handleErr(err)
-	args := os.Args[1:]
-	argsLen := len(args)
-	// Flag checking (--host, -h, --help, --port, and --zip)
-	for x := 0; x < argsLen; x++ {
-		switch strings.ToLower(args[x]) {
-		case "-h", "--help":
-			displayHelp()
-			os.Exit(0)
-		case "--host":
-			// User specified TCP listening address
-			hostVal, err := getFlagStrValue(args, x, argsLen)
-			x++
-			handleErr(err)
-			host = hostVal
-		case "--port":
-			// User specified TCP listening port
-			portVal, err := getFlagPortValue(args, x, argsLen)
-			x++
-			handleErr(err)
-			port = portVal
-		case "--zip":
-			// User specified ZIP file path
-			zipFilePathVal, err := getFlagStrValue(args, x, argsLen)
-			x++
-			handleErr(err)
-			zipFilePath = zipFilePathVal
-		}
-	}
-}
-
-func main() {
-	getZIPFileReader()
-	defer zipReader.Close()
-	fmt.Printf("Starting Gopherhole at gopher://%s:%d\n",
-		host, port)
-	startGopherServer()
-}
diff --git a/gopher-server/gen-polyglot.sh b/gopher-server/gen-polyglot.sh
new file mode 100755
index 0000000..955d5d0
--- /dev/null
+++ b/gopher-server/gen-polyglot.sh
@@ -0,0 +1,40 @@
+#!/bin/bash
+
+# This program builds gopher-server and generates an executable+ZIP
+# polyglot file.  A file called "cat.zip" will be created as a
+# byproduct and can be removed after.  The resulting polyglot file
+# will be called "gopher-server-zip-polyglot.zip"
+
+# Be sure to set the Go OS and Go Arch to what system you want the
+# compiled Go program to be for
+goos="linux"
+goarch="amd64"
+
+# Possible GOOS/GOARCH options
+# aix/ppc64        freebsd/amd64   linux/mipsle   openbsd/386
+# android/386      freebsd/arm     linux/ppc64    openbsd/amd64
+# android/amd64    illumos/amd64   linux/ppc64le  openbsd/arm
+# android/arm      js/wasm         linux/s390x    openbsd/arm64
+# android/arm64    linux/386       nacl/386       plan9/386
+# darwin/386       linux/amd64     nacl/amd64p32  plan9/amd64
+# darwin/amd64     linux/arm       nacl/arm       plan9/arm
+# darwin/arm       linux/arm64     netbsd/386     solaris/amd64
+# darwin/arm64     linux/mips      netbsd/amd64   windows/386
+# dragonfly/amd64  linux/mips64    netbsd/arm     windows/amd64
+# freebsd/386      linux/mips64le  netbsd/arm64   windows/arm
+
+if [ -z "$1" ]; then
+	echo "Must include path to ZIP file"
+else
+	# Build the gopher server executable
+	# Concatenate executable with ZIP file to make polyglot file
+	# Realign offsets of ZIP file so ZIP file works again
+	echo "Building for gopher-server for $goos/$goarch" && \
+		GOOS="$goos" GOARCH="$goarch" go build -ldflags="-s -w" -o "./gopher-server" && \
+		cat "./gopher-server" "$1" > "cat.zip" && \
+		zip -F "cat.zip" --out "gopher-server-zip-polyglot.zip" && \
+		echo "gopher-server-zip-polyglot.zip Created for $goos/$goarch." && \
+		echo "You can make gopher-server-zip-polyglot.zip executable with:" && \
+		echo "  chmod +x gopher-server-zip-polyglot.zip"
+	echo "You can delete cat.zip."
+fi
diff --git a/go.mod b/gopher-server/go.mod
similarity index 100%
rename from go.mod
rename to gopher-server/go.mod
diff --git a/gopher-server/gopher-server.go b/gopher-server/gopher-server.go
new file mode 100644
index 0000000..654d308
--- /dev/null
+++ b/gopher-server/gopher-server.go
@@ -0,0 +1,313 @@
+/*
+ +------------------------+
+ |     Gopher Server      |
+ | Programmed by Vi Grey  |
+ +------------------------+
+
+ This is meant to be compiled and prepended to a ZIP file to make it an
+ Executable+ZIP polyglot file with the intention of the ZIP file
+ hosting the content for the Gopherhole.
+
+ If run without any arguments, the ZIP file will be the executable
+ itself, and the Gopherhole will be listening on localhost:2311 (2311
+ chosen because 2023-11 for the release of tmp.0ut Volume 3)
+
+ Do whatever the heck you want to with this code, just don't blame me
+ if anything happens...
+
+ GO GOLDEN GOPHERS!
+*/
+
+package main
+
+import (
+	"archive/zip"
+	"fmt"
+	"io"
+	"log"
+	"mime"
+	"net"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	DEFAULT_CONTENT = `itmp.0ut #003 - 2023-11		fake	0
+i		fake	0
+001 Intro ~ t0	/txt/1.txt	{ADDR}	{PORT}
+002 Second Part To Hell Interview ~ t0	/txt/2.txt	{ADDR}	{PORT}
+003 UNIX VIRUSES 25th Anniversary ~ silvio	/txt/3.txt	{ADDR}	{PORT}
+004 Hijacking __cxa_finalize to achieve entry point obscuring ~ vrzh	/txt/4.txt	{ADDR}	{PORT}
+005 Linux.ElizaCanFix.asm ~ vrzh	/txt/5.txt	{ADDR}	{PORT}
+006 Concealing Namespaces Within a File Descriptor ~ Fanda Uchytil	/txt/Linux.ElizaCanFix.asm	{ADDR}	{PORT}
+007 Dumping libc memory space to bypass ASLR ~ jonaslyk	/txt/7.txt	{ADDR}	{PORT}
+008 ARM32 ELF Sizecoding ~ deater	/txt/8.txt	{ADDR}	{PORT}
+009 A Silver Bullet To ELF Projects ~ echel0n	/txt/9.txt	{ADDR}	{PORT}
+010 in-memory-only fd-less ELF execution (with Perl) ~ isra	/txt/10.txt	{ADDR}	{PORT}
+011 isra_exec_elf64.pl ~ isra	/txt/isra_exec_elf64.pl	{ADDR}	{PORT}
+012 u used 2 call me on my polymorphic shell phone ~ ic3qu33n	/txt/12.txt	{ADDR}	{PORT}
+013 Weird ELFs, or a tale of breaking parsers once again ~ g1inko	/txt/13.txt	{ADDR}	{PORT}
+014 inspect0rGadget.asm - x64 ROP Gadget Finder ~ s01den	/txt/14.txt	{ADDR}	{PORT}
+015 Reverse Text Disinfector ~ qkumba	/txt/15.test-1.c	{ADDR}	{PORT}
+016 RE of Linux.Nasty.asm ~ qkumba	/txt/16.txt	{ADDR}	{PORT}
+017 Linux.Anansi.c ~ sad0p	/txt/Linux.Anansi.c	{ADDR}	{PORT}
+018 Linux.Slinger.asm ~ lvti	/txt/Linux.Slinger.asm	{ADDR}	{PORT}
+019 LKM Golf ~ rqu & netspooky	/txt/19.txt	{ADDR}	{PORT}
+020 easylkb: Easy Linux Kernel Builder ~ ackmage & netspooky	/txt/20.txt	{ADDR}	{PORT}
+021 23 Open Problems for Digital Self-Replicators ~ Second Part To Hell	/txt/21.txt	{ADDR}	{PORT}
+022 Cramming a Tiny Program into a Tiny ELF File: A Case Study ~ lm978	/txt/22.txt	{ADDR}	{PORT}
+023 silent syscall hooking on arm64 linux by patching svc handler ~ wintermute	/txt/23.txt	{ADDR}	{PORT}
+024 HVice - HyperVisor intrusion countermeasure electronics ~ wintermute	/txt/24.txt	{ADDR}	{PORT}
+025 BGGP4 Recap ~ Binary Golf Association	/txt/25.txt	{ADDR}	{PORT}
+026 LLMorpher ~ Second Part To Hell	/txt/26.txt	{ADDR}	{PORT}
+027 QRLog Malware Analysis ~ mauro	/txt/27.txt	{ADDR}	{PORT}
+028 HandJar.B ~ r3s1stanc3	/txt/28.txt	{ADDR}	{PORT}
+029 ClassWar ~ r3s1stanc3	/txt/29.txt	{ADDR}	{PORT}
+030 linkin.pl ~ isra	/txt/linkin.pl	{ADDR}	{PORT}
+031 Long Live Gopher! This Zine Is Also A Gopher Server ~ Vi Grey	/txt/31.txt	{ADDR}	{PORT}
+i		fake	0
+iFor the html version of this zine, please visit		fake	0
+hhttps://tmpout.sh/3/	URL:https://tmpout.sh/3/	fake	0`
+)
+
+var (
+	port        = 2311
+	host        = "localhost"
+	zipFlag     bool
+	zipFilePath string
+	zipReader   *zip.ReadCloser
+)
+
+// Print error log and close program with error code 1 if err not nil
+func handleErr(err error) {
+	if err != nil {
+		log.Fatalf("%s\nExiting...\n", err)
+	}
+}
+
+// Return MIME type based on file extension of path
+func getMIMEType(path string) string {
+	return mime.TypeByExtension(strings.ToLower(filepath.Ext(path)))
+}
+
+// Open ZIP file and get Reader
+func getZIPFileReader() {
+	var err error
+	zipReader, err = zip.OpenReader(zipFilePath)
+	handleErr(err)
+}
+
+func sendGeneratedGophermap(reqPath string, conn net.Conn) {
+	reqPathFull := filepath.Join("/", reqPath)
+	if reqPathFull != "/" {
+		// Add slash to reqPath if it's not root path
+		reqPathFull += "/"
+	}
+	conn.Write([]byte(fmt.Sprintf("i%s Gophermap\t\tfake\t0\r\n", reqPathFull)))
+	for _, zipFile := range zipReader.File {
+		filename := filepath.Join("/", zipFile.Name)
+		if strings.Index(filename, reqPathFull) == 0 {
+			//zipFile exists inside reqPath
+			// Get path name without reqPath
+			p := filename[len(reqPathFull):]
+			if filepath.Dir(p) == "." {
+				// Path is a is in the base directory of reqPath
+				itemType := "0"
+				mimeType := getMIMEType(p)
+				switch {
+				case zipFile.FileInfo().IsDir():
+					// Path is a directory
+					// Add "/" to end of file name to show it's a directory
+					itemType = "1"
+					p = filepath.Join(p) + "/"
+					conn.Write([]byte(fmt.Sprintf("1%s\t%s\t%s\t%d\r\n",
+						filepath.Join(p)+"/", filename, host, port)))
+				case strings.Contains(mimeType, "image/"):
+					// Path is an image
+					if strings.Contains(mimeType, "image/gif") {
+						itemType = "g"
+					} else {
+						itemType = "I"
+					}
+				case strings.Contains(mimeType, "audio/"):
+					// Path is audio
+					itemType = "s"
+				}
+				// so line is txt file line
+				conn.Write([]byte(fmt.Sprintf("%s%s\t%s\t%s\t%d\r\n",
+					itemType, p, filename, host, port)))
+			}
+		}
+	}
+	conn.Write([]byte(".\r\n"))
+}
+
+// Get request from gopher client and serve page from ZIP file if path
+// exists inside of ZIP file
+func handleGopherConnection(conn net.Conn) {
+	var rBuf []byte
+	var request string
+	// Continue reading from connection until first \r\n is found
+	for {
+		rBuf = make([]byte, 2048)
+		n, err := conn.Read(rBuf)
+		if err != nil || n == 0 {
+			break
+		}
+		request += string(rBuf[:n])
+		// Gopher path request ends at first instance of \r\n
+		nlIndex := strings.Index(request, "\r\n")
+		if nlIndex > -1 {
+			reqPath := request[:nlIndex] // Gopher path request
+			if reqPath == "" || reqPath == "/" {
+				// reqPath is the root gophermap
+				if !zipFlag {
+					// zipFlag was not specified, so should be polyglot ZIP
+					// Replace {PORT} and {ADDR} of DEFAULT_CONTENT to specified
+					// values
+					gophermap := strings.Replace(DEFAULT_CONTENT, "{PORT}",
+						strconv.Itoa(port), -1)
+					gophermap = strings.Replace(gophermap, "{ADDR}",
+						host, -1)
+					conn.Write([]byte(gophermap))
+					conn.Write([]byte("\r\n.\r\n"))
+					return
+				} else {
+					sendGeneratedGophermap(reqPath, conn)
+					return
+				}
+			} else {
+				for _, zipFile := range zipReader.File {
+					if filepath.Join("/", reqPath) == filepath.Join("/", zipFile.Name) {
+						// /reqPath is in zip directory root
+						if zipFile.FileInfo().IsDir() {
+							// reqPath is directory
+							sendGeneratedGophermap(reqPath, conn)
+							return
+						} else {
+							// reqPath is file
+							f, err := zipFile.Open()
+							handleErr(err)
+							defer f.Close()
+							// Write file content from zip file to connection
+							io.Copy(conn, f)
+							conn.Write([]byte("\r\n.\r\n"))
+							return
+						}
+					}
+				}
+			}
+			// Send error to gopher client.  Essentially the same as HTTP 404
+			conn.Write([]byte("3The selected resource does not exist\tfake\t" +
+				"fake\t0\r\n.\r\n"))
+			return
+		}
+	}
+	// Send error to gopher client.  Essentially the same as HTTP 400
+	conn.Write([]byte("3Invalid Request\tfake\tfake\t0\r\n.\r\n"))
+}
+
+// Start the gopher server at specified host and port (default
+// localhost:2311)
+func startGopherServer() {
+	listener, err := net.Listen("tcp",
+		fmt.Sprintf("%s:%d", host, port))
+	handleErr(err)
+	for {
+		if conn, err := listener.Accept(); err == nil {
+			go func() {
+				defer conn.Close()
+				// Close connection when request handled or after 30 seconds
+				conn.SetReadDeadline(time.Now().Add(30 * time.Second))
+				handleGopherConnection(conn)
+			}()
+		}
+	}
+}
+
+// Display help message and close program
+func displayHelp() {
+	fmt.Printf(`Usage %s [OPTIONS]...
+
+Options:
+  -h, --help              Print Help (this message) and exit
+      --host <name>       TCP address for gopher server to listen on
+                          (default: "localhost")
+      --port <num>        TCP port to listen on (default: 2311)
+      --zip <path>        Path to ZIP file that hosts the content
+                          (default: this executable file itself)
+`, os.Args[0])
+}
+
+// Get a string value from args[x+1]
+func getFlagStrValue(args []string, x, argsLen int) (string, error) {
+	if x+1 >= argsLen {
+		err := fmt.Errorf("%s: flag `%s` missing value\n Use `%s --help` for "+
+			"details", os.Args[0], args[x], os.Args[0])
+		return "", err
+	}
+	return args[x+1], nil
+}
+
+// Get an integer value of 1-65535 from args[x+1]
+func getFlagPortValue(args []string, x, argsLen int) (int, error) {
+	strVal, err := getFlagStrValue(args, x, argsLen)
+	if err != nil {
+		return 0, err
+	}
+	portVal, _ := strconv.Atoi(strVal)
+	if portVal < 1 || portVal > 65535 {
+		err = fmt.Errorf("%s: flag `%s` value must be a number value of "+
+			"1-65535\nUse `%s --help` for details",
+			os.Args[0], args[x], os.Args[0])
+		return 0, err
+	}
+	return portVal, nil
+}
+
+func init() {
+	var err error
+	// Get executable path in case --zip flag not used
+	zipFilePath, err = os.Executable()
+	handleErr(err)
+	args := os.Args[1:]
+	argsLen := len(args)
+	// Flag checking (--host, -h, --help, --port, and --zip)
+	for x := 0; x < argsLen; x++ {
+		switch strings.ToLower(args[x]) {
+		case "-h", "--help":
+			displayHelp()
+			os.Exit(0)
+		case "--host":
+			// User specified TCP listening address
+			hostVal, err := getFlagStrValue(args, x, argsLen)
+			x++
+			handleErr(err)
+			host = hostVal
+		case "--port":
+			// User specified TCP listening port
+			portVal, err := getFlagPortValue(args, x, argsLen)
+			x++
+			handleErr(err)
+			port = portVal
+		case "--zip":
+			// User specified ZIP file path
+			zipFilePathVal, err := getFlagStrValue(args, x, argsLen)
+			x++
+			handleErr(err)
+			zipFilePath = zipFilePathVal
+			zipFlag = true
+		}
+	}
+}
+
+func main() {
+	getZIPFileReader()
+	defer zipReader.Close()
+	fmt.Printf("Starting Gopherhole at gopher://%s:%d\n",
+		host, port)
+	startGopherServer()
+}
diff --git a/index.gph b/index.gph
deleted file mode 100644
index 44987f2..0000000
--- a/index.gph
+++ /dev/null
@@ -1,6 +0,0 @@
-itmp.0ut Volume 3 - November 2023		fake	0
-i		fake	0
-03.0 Intro (tmp.0ut Staff)	/txt/0.txt	localhost	2311
-03.X Title (Author)	/txt/path.txt	localhost	2311
-03.X Title (Author)	/txt/path.txt	localhost	2311
-03.X Title (Author)	/txt/path.txt	localhost	2311
diff --git a/index.gph-example b/index.gph-example
deleted file mode 100644
index ff92070..0000000
--- a/index.gph-example
+++ /dev/null
@@ -1,20 +0,0 @@
-itmp.0ut Volume 1 - April 2021		fake	0
-i		fake	0
-01.0 Intro (tmp.0ut Staff)	/txt/0.txt	localhost	2311
-01.1 Dead Bytes (xcellerator)	/txt/1.txt	localhost	2311
-01.2 Implementing the PT_NOTE Infection Method In x64 Assembly (sblip)	/txt/2.txt	localhost	2311
-01.3 PT_NOTE To PT_LOAD ELF Injector In Rust (d3npa)	/txt/3.txt	localhost	2311
-01.4 PT_NOTE Disinfector In Python (manizzle)	/txt/4.txt	localhost	2311
-01.5 Fuzzing Radare2 For 0days In About 30 Lines Of Code (Architect, s01den)	/txt/5.txt	localhost	2311
-01.6 The Polymorphic False-Disassembly Technique (s01den)	/txt/6.txt	localhost	2311
-01.7 Lin64.Eng3ls: Some Anti-RE Techniques In A Linux Virus (s01den, sblip)	/txt/7.txt	localhost	2311
-01.8 Linux.Midrashim.asm (TMZ)	/txt/Linux.Midrashim.asm	localhost	2311
-01.9 In-Memory LKM Loading (netspooky)	/txt/9.txt	localhost	2311
-01.10 Linux SHELF Loading (ulexec, Anonymous_)	/txt/10.txt	localhost	2311
-01.11 Return To Original Entry Point Despite PIE (s01den)	/txt/11.txt	localhost	2311
-01.12 Writing Viruses In MIPS Assembly For Fun (And No Profit) (s01den)	/txt/12.txt	localhost	2311
-01.13 Interview: herm1t (tmp.0ut Staff)	/txt/13.txt	localhost	2311
-01.14 GONE IN 360 SECONDS - Linux/Retaliation (qkumba)	/txt/14.txt	localhost	2311
-01.15 Linux.Nasty.asm (TMZ)	/txt/Linux.Nasty.asm	localhost	2311
-01.16 Linux.Precinct3.asm (netspooky)	/txt/Linux.Precinct3.asm	localhost	2311
-01.17 Underground Worlds (s01den)	/txt/17.txt	localhost	2311
diff --git a/polyglot-instructions.txt b/polyglot-instructions.txt
deleted file mode 100644
index c618125..0000000
--- a/polyglot-instructions.txt
+++ /dev/null
@@ -1,38 +0,0 @@
-Dependencies:
-
-* go >= 1.15
-* zip
-
-
-1.) Compile go program:
-
-```
-go build
-```
-
-if you want to make the resulting binary file smaller, you can compile with:
-
-```
-go build -ldflags="-s -w"
-```
-
-2.) Concatenate the compiled program and ZIP file:
-
-```
-cat gopher-server zip-file.zip > cat.zip
-```
-
-3.) Fix ZIP file offsets:
-
-```
-zip -F cat.zip --out out.zip
-```
-
-4.) Make polyglot file executable if you want to run the file:
-
-```
-chmod +x out.zip
-```
-
-If you want to use --port or --host flags, please make sure index.gph
-file at root of ZIP file has the matching port and host information.