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7 changed files with 243 additions and 75 deletions
+26 -8
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@@ -1,12 +1,30 @@
all: client server
server_clean:
rm server
re: clean client server
client_clean:
rm client
clean:
rm client.o server.o
client:
go build -o client.o client.go
clean: server_clean client_clean
server:
go build -o server.o server.go
go build server.go
client:
go build client.go
build: server client
ins_server:
go build -o ekho_server server.go
mv ekho_server /usr/local/bin/
cp ekho.service /etc/systemd/system/ekho.service
mkdir -p ~/.config/ekho
ln -s -r ./list.q ~/.config/ekho/list.q
systemctl daemon-reload
systemctl enable ekho
systemctl start ekho
systemctl status ekho
ins_client:
go build -o ekho client.go
mv ekho /usr/local/bin/
+50 -46
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@@ -3,80 +3,84 @@
## Why?
To test my abilities to develop networked programs, and to enhance my skills in writing such.
## Requirements
### Hardware
- Client machine
- Server machine (not required to be distinct from Client)
### Software
- [Golang]
- Linux distro (highly recommened)
- ```make``` is also used in this guide, but the makefile is incredibly simple, and can be skipped entirely by running ```go build``` instead
- Tested with [golang] v1.26
- Installation has only been tested with [just] v1.53
- Server installation assumes systemd (tested with v260.2)
### Installation
Golang can be installed on Mac with
``` sh
brew install golang
```
Clone the repo
``` sh
git clone https://github.com/alexander-the-alright/ekho
cd ekho
```
Using your favorite text editor, change the destination IP and Port to whatever works for you. This is defined on line 247 in client.go as 127.0.0.1:1300.
Now the server file needs to be run on the preferred port, as specified in the client file. This is defined on line 257 in server.go.
#### Justfile
It is recommended to use ```just``` for installation, as it has more
capabilities than ```make```, however, there is a makefile included.
To install the server with ```just```, run ```sudo just ins_server```.
You will be prompted to enter a new port number to run the server on (
or leave blank to use 1300). The port will be changed in the source
file before compilation.
To install the client with ```just```, run ```sudo just ins_client```.
You will be prompted to enter the IP (or URL) and port of the server
(or leave blank to use localhost:1300). The IP/URL and port will be
changed in the source file before compilation.
#### Makefile
If you are unable or willing to use ```just```, the included makefile
still has most of the functionality, but it does not change any
important parameters. The following changes are advised before
installation.
The binary(s) can be obtained using the makefile
If the server is being run on a separate machine, only run make with client flag
``` sh
make client
```
If both binaries are being run on the same machine, ```make all``` will suffice. Although, both of these commands can be bypassed with ```go build```, as this is all ```make``` does anyway.
``` sh
make all
```
1. On the client machine, change the IP/URL and port in the client source file. This can be
done quickly with ```sed -i -e "s/127.0.0.1:1300/YOUR.IP.GOES.HERE:PORT/" client.go```
2. On the server machine, change the port in the server source file. This can be done with a
similar command: ```sed -i -e "s/1300/PORT/" server.go```. (note: this
should match the port from bullet 1)
3. On the server machine, change the user referenced in the systemd service file. This can be
done with another sed command, ```sed -e -i "s/USER/YOUR_USERNAME/" ekho.service```
#### NOTE
In previous versions, the suggested method of installation involved placing bash scripts in ```/etc/update-motd.d/```, however, there have been issues getting that installation method working (namely, having MOTD run user-defined commands), and the current quick and extremely dirty suggested installation method is to just append the user's shell config files (```.bashrc```, ```.bash_profile```, ```.zshrc```, etc) with the paths to the executables.
After making these changes on the respective machines, run either
```sudo make ins_client``` or ```sudo make ins_server``` to compile and install the client
and/or server binaries.
For example, if the server used zsh, the installation could look something like this:
``` sh
echo "~/abs/path/to/server.o &" >> ~/.zshrc
```
Similarly for a client using Bash:
``` sh
echo "~/abs/path/to/client.o" >> ~/.bashrc
```
Any help figuring out the issue with MOTD would be appreciated.
#### After Installation
After installation of the server binary, systemd will display the
status of the new service. It should be ```enabled``` and
```running```.
Finally done!
### Usage
The client uses the following flags
``` sh
-h - display help message
-a <s> - adds required argument <s> as a quote to server
-l - list all quotes
-r [i] - remove; may be run with or without argument
-ip - specify alternate server destination
-s - specify the size of the receipt buffer
-h - display help message
-a <string> - adds required argument <s> as a quote to server
-ip <ip:port> - specify alternate server destination
-l - list all quotes
-r [i] - remove; may be run with or without argument
-s <i> - specify the size of the receipt buffer
```
The server uses the following flags
``` sh
-h - display help message
-s - specify the size of the receipt buffer
-s <i> - specify the size of the receipt buffer
-v - display version and exit
-vv - display version and about info and exit
```
### How It Works
The sequence diagram can be viewed in ```diag``` folder, which shows the sequence of networked messages for each usage of ekho.
The source code is in the same folder, ```ekho-seq.txt```, and can be uploaded to [sequencediagram.org][seqdiag] to rerender the diagram and view any updates.
### To Be Implemented
- Log all uses/transaction data each day
- Request, send, and receive the logfile for any day
- Request, send, and receive the logfile
- User-specific quotes/quotefiles
- Installation (client-side, at least) via MOTD
- Colored printing and coloring quotes
- Edit quotes
[golang]: <https://go.dev/doc/install>
[seqdiag]: <sequencediagram.org>
[just]: <https://github.com/casey/just>
+1 -1
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@@ -339,7 +339,7 @@ func main() {
flag.BoolVar( &add, "a", false, "add quote to list" )
flag.BoolVar( &remove, "r", false, "remove quote from list" )
flag.BoolVar( &list, "l", false, "print quote list" )
flag.StringVar( &dest, "ip", ":1300", "ip:port of server" )
flag.StringVar( &dest, "ip", "127.0.0.1:1300", "ip:port of server" )
flag.IntVar( &tsize, "s", 256, "transmission size ( bytes )" )
flag.Parse() // process flags
+14
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@@ -0,0 +1,14 @@
[Unit]
Description=Ekho MOTD Server
After=network.target
[Service]
Type=simple
Restart=always
RestartSec=5
User=USER
ExecStart=/usr/local/bin/ekho_server
WorkingDirectory=/home/USER/.config/ekho
[Install]
WantedBy=multi-user.target
+69
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@@ -0,0 +1,69 @@
# delete server bin
[private]
server_clean:
rm server
# delete client bin
[private]
client_clean:
rm client
# delete binaries
clean: server_clean client_clean
# build server bin
server:
go build server.go
# build client bin
client:
go build client.go
# build both bins
build: client server
# delete binaries and make them again
rebuild: clean build
# install server
ins_server:
#!/usr/bin/bash
echo "enter port of server or leave blank to use default (1300)"
read PORT
if [[ $PORT -ne "" ]]; then
sed -i -e "s/1300/$PORT/" server.go
fi
echo "go build -o ekho_server server.go"
go build -o ekho_server server.go
echo "mv ekho_server /usr/local/bin/"
mv ekho_server /usr/local/bin/
USER=($(users))
sed -i -e "s/USER/${USER[0]}/" ekho.service
echo "cp ekho.service /etc/systemd/system/"
cp ekho.service /etc/systemd/system/
mkdir -p ~/.config/ekho
echo "ln -s -r ./list.q ~/.config/ekho/list.q"
ln -s -r ./list.q ~/.config/ekho/list.q
echo "systemctl daemon-reload"
systemctl daemon-reload
echo "systemctl enable ekho"
systemctl enable ekho
echo "systemctl start ekho"
systemctl start ekho
echo "systemctl status ekho"
systemctl status ekho
# install client
ins_client:
#!/usr/bin/bash
echo "enter url or ip and port of server, 'aaa.bbb.ccc.ddd:port"
read IP_PORT
sed -i -e "s/:1300/$IP_PORT/" client.go
echo "go build -o ekho client.go"
go build -o ekho client.go
sed -i -e "s/$IP_PORT/:1300/" client.go
echo "mv ekho /usr/local/bin/"
mv ekho /usr/local/bin/
echo "add 'ekho' to shell config (config.fish, .bashrc, etc)"
+8
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@@ -1 +1,9 @@
@user:
shmuley
floglin
@all:
blingo
no but like actually blingo shmingo
i would prefer not to
@default:
thank you for using ekho
+75 -20
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@@ -1,14 +1,17 @@
// =============================================================================
// Auth: alex
// File: server.go
// Revn: 01-09-2025 5.0
// Revn: 05-12-2026 2.1.2
// Func: host MOTD connection
//
// TODO: remove ioutil import
// add more /codes/ to handle
// add flags, like specify port
// TODO:
// add user-specific prints
// write usage and errors to logfile
// remove ioutil import
// send logfile to client on request
// add color printing to qfile
// add flags?
// add more /codes/ to handle
// =============================================================================
// CHANGE LOG
// -----------------------------------------------------------------------------
@@ -31,7 +34,7 @@
// fixed bug in /r2/ where removing quote at final
// position would break
// removed deadcode from /r2/, unused "quit" bool?
//*10-17-2023: fixed bug where quotes are read from and saved to two
//#10-17-2023: fixed bug where quotes are read from and saved to two
// different files
// removed implicit newline at end of qfile to stop ghost
// line bug in /la/
@@ -43,7 +46,11 @@
// commented
//*06-14-2024: byte count-based PWFT rewrite
//*06-17-2024: catch keyboard interrupts with os/signal and syscall
//*01-09-2025: copied lr/la PWFT updates into r1/r2
//#01-09-2025: copied lr/la PWFT updates into r1/r2
//*04-28-2026: removed implicit newline at end of qfile to stop ghost
// line bug in /la/ AGAIN
// 05-11-2026: updated fread() to handle users in qfile
// 05-12-2026: added v and vv input flags
//
// =============================================================================
@@ -114,10 +121,15 @@ func fread() string {
// bugs where a blank item was introduced into qlist and calling
// /la/ would produce a blank line on the client side that didn't
// really exist
//qfile = qfile[:len( qfile ) - 1]
qfile = qfile[:len( qfile ) - 1]
// cast bytes to string, split string over newline into array
qlist = strings.Split( string( qfile ), "\n" )
// deal with the trailing
//qlist = strings.Split( string( qfile ), "\n" )
profiles := strings.Split( string( qfile ), "@" )
for _, p := range profiles {
quotes := strings.Split( p, ":" )
qlist[quotes[0]] = strings.Split( quotes[1], "\n" )
}
return string( qfile ) // return file as string
}
@@ -143,6 +155,17 @@ func handle( conn net.Conn ) {
n, err := conn.Read( buffer[:] )
checkN( err, conn ) // make sure read worked
// message anatomy
// command@number[@user]
// @ @ delimiter
// command command, like list request or quote request
// number sequence or quote number
// user quote username if applicable, default if not give
// add request message anatomy
// command@quote[@user]
// quote quote to be added
// user quote username, default if not given
// cast message to string, take first n bytes, split over @
command := strings.Split( string( buffer[:n] ), "@" )
@@ -156,9 +179,20 @@ func handle( conn net.Conn ) {
// concat and send
resp = "sa@" + num // size answer
case "qr": // /qr/, quote request
// see if user was sent
subcommands := strings.Split( command[1], ":" )
// keep track of name, or default if need be
var name string
if len( subcommands ) == 1 {
name = "default"
} else {
name = subcommands[1]
}
// convert message argument to string to make sure it's a
// valid number
num, nerr := strconv.Atoi( command[1] )
num, nerr := strconv.Atoi( subcommands[0] )
// nerr will not be nil if comm[1] is not a number
if nerr != nil {
// formulate an error message
@@ -166,7 +200,7 @@ func handle( conn net.Conn ) {
resp = "ba@qr@!" // bad answer
} else { // comm[1] was a number, but...
switch { // how do we know it's a valid number
case num > len( qlist ):
case num > len( qlist[name] ):
// bad answer in quote request
resp = "ba@qr@>"
// why bad? num is >
@@ -176,7 +210,7 @@ func handle( conn net.Conn ) {
// why bad? num is -
default:
// good num, get quote, send off
resp = "qa@" + qlist[num] // quote answer
resp = "qa@" + qlist[name][num] // quote answer
}
}
case "lr": // /lr/, list request
@@ -218,7 +252,7 @@ func handle( conn net.Conn ) {
}
case "ar": // /ar/, add request
// append new quote to list
qlist = append( qlist, command[1] )
qlist["f"] = append( qlist["f"], command[1] )
// also append new quote to file variable
qfile = qfile + "\n" + command[1]
writeFile( qfile )
@@ -285,14 +319,14 @@ func handle( conn net.Conn ) {
default:
// replace the quote at that position with
// final quote
qlist[num] = qlist[len( qlist ) - 1]
qlist["f"][num] = qlist["f"][len( qlist ) - 1]
// remove second copy of quote
qlist = qlist[:len( qlist ) - 1]
qlist["f"] = qlist["f"][:len( qlist ) - 1]
// O(1) remove from list at any position
// must entirely recreate quote string
var f string = "" // init empty string
// iterate over list, disregard index
for _, v := range qlist {
for _, v := range qlist["f"] {
// add next quote to file and separate
// quotes with newline
f = f + v + "\n"
@@ -332,10 +366,11 @@ func handle( conn net.Conn ) {
// globals
var qlist []string // list of quotes
//var qlist []string // list of quotes
var qlist = make( map[string][]string )
var qfile string // file object
var tsize int // size of transmission buffer
var VERS string // version
// main, create port and wait for connection
func main() {
@@ -345,12 +380,32 @@ func main() {
// set interrupt and terminate signals to notify channel
signal.Notify( sigs, syscall.SIGINT, syscall.SIGTERM )
// flag vars
var v bool // simple version
var vv bool // verbose version
// flag for default transmission size
flag.IntVar( &tsize, "s", 256, "transmission size ( bytes )" )
flag.IntVar( &tsize, "s", 256, "transmission size ( bytes )" )
flag.BoolVar( &v, "v", false, "display version and exit" )
flag.BoolVar( &vv, "vv", false, "display version and about info and exit" )
flag.Parse()
qfile = fread() // read quote file, init ( global ) list of quotes
// FIXME get better versioning method
VERS = "2.1.2"
if vv { // display info and exit
fmt.Println( "ekho server v" + VERS )
fmt.Println( "ekho is named after Echo the Oread" )
fmt.Println( "in Greek mythology, Echo was cursed by Hera to only be able to say the last words spoken to her" )
fmt.Println( "i found this to be quite fitting for a MOTD server" )
return
} else if v { // display info and exit
fmt.Println( VERS )
return
}
qfile = fread() // read quote file, init ( global ) list of quotes
service := ":1300" // create service on ip and port
// resolve ip address and port