town/cmd/appendkeyfile/main.go

60 lines
1.2 KiB
Go

package main
/*
The purpose of this command is to be run via sudo as an arbitrary user by the "help" user. It is invoked as part of the "i need to add a new public key" flow from "ssh help@tilde.town".
It's based on the createkeyfile helper and heavily copy pasta'd. They should probably share code or be a single command but I wanted to keep things simple for now.
*/
import (
"fmt"
"os"
"os/user"
"path"
)
const keyfileName = "authorized_keys2"
func quit(msg string, code int) {
// TODO print to stderr
fmt.Println(msg)
os.Exit(code)
}
func main() {
u, err := user.Current()
if err != nil {
quit(err.Error(), 2)
}
sshPath := path.Join("/home", u.Username, ".ssh")
keyfilePath := path.Join(sshPath, keyfileName)
f, err := os.OpenFile(keyfilePath, os.O_APPEND|os.O_WRONLY, 0600)
if err != nil {
quit(fmt.Sprintf("failed to open %s: %s", keyfilePath, err.Error()), 5)
}
defer f.Close()
stdin := make([]byte, 90000) // arbitrary limit
n, err := os.Stdin.Read(stdin)
if err != nil {
quit(err.Error(), 6)
} else if n == 0 {
quit("nothing passed on STDIN", 7)
}
stdin = stdin[0:n]
n, err = f.Write(stdin)
if err != nil {
quit(err.Error(), 9)
} else if n == 0 {
quit("wrote nothing to keyfile", 10)
}
}