1db9dbe390 2024-11-28 1: //! Simple SMTP-to-Telegram gateway. Can parse email and send them as telegram
1db9dbe390 2024-11-28 2: //! messages to specified chats, generally you specify which email address is
1db9dbe390 2024-11-28 3: //! available in configuration, everything else is sent to default address.
1db9dbe390 2024-11-28 4:
ac6ac8c108 2026-09-25 5: use std::{
ac6ac8c108 2026-09-25 6: os::unix::fs::PermissionsExt,
ac6ac8c108 2026-09-25 7: path::Path,
ac6ac8c108 2026-09-25 8: };
ac6ac8c108 2026-09-25 9:
ac6ac8c108 2026-09-25 10: use clap::Parser;
42ac4c7a9a 2026-10-28 11: use smol::fs::metadata;
ac6ac8c108 2026-09-25 12: use stacked_errors::{
ac6ac8c108 2026-09-25 13: Result,
ac6ac8c108 2026-09-25 14: StackableErr,
ac6ac8c108 2026-09-25 15: bail,
ac6ac8c108 2026-09-25 16: };
ac6ac8c108 2026-09-25 17:
ac6ac8c108 2026-09-25 18: use smtp2tg::mail::MailServer;
ac6ac8c108 2026-09-25 19:
ac6ac8c108 2026-09-25 20: /// SMTP-to-Telegram gateway
ac6ac8c108 2026-09-25 21: #[derive(Parser, Debug)]
ac6ac8c108 2026-09-25 22: #[command(name = "smtp2tg")]
ac6ac8c108 2026-09-25 23: #[command(about = format!("SMTP-to-Telegram gateway v{}, (C) 2024 - 2026", env!("CARGO_PKG_VERSION")), long_about = None)]
ac6ac8c108 2026-09-25 24: struct Args {
ac6ac8c108 2026-09-25 25: /// Set configuration file location
ac6ac8c108 2026-09-25 26: #[arg(short, long, default_value = "smtp2tg.toml")]
ac6ac8c108 2026-09-25 27: config: String,
ac6ac8c108 2026-09-25 28: }
3c858ed7c4 2026-07-31 29:
ac6ac8c108 2026-09-25 30: /// Main asynchronous entry point for the application. Runs the gateway using
ac6ac8c108 2026-09-25 31: /// the configuration selected on the command line.
ac6ac8c108 2026-09-25 32: ///
ac6ac8c108 2026-09-25 33: /// The configuration file must use owner-only permissions. Once configured,
ac6ac8c108 2026-09-25 34: /// the SMTP server runs until it stops or encounters an error.
ac6ac8c108 2026-09-25 35: ///
ac6ac8c108 2026-09-25 36: /// # Errors
ac6ac8c108 2026-09-25 37: /// Returns an error if the configuration file is missing, inaccessible,
ac6ac8c108 2026-09-25 38: /// insecure, malformed, or contains invalid required settings.
ec55d3e69e 2026-10-28 39: /// Also returns an error if the system hostname cannot be read or is not
ec55d3e69e 2026-10-28 40: /// valid UTF-8, or if mail server initialisation fails.
ac6ac8c108 2026-09-25 41: ///
ac6ac8c108 2026-09-25 42: /// # Panics
ac6ac8c108 2026-09-25 43: /// Panics if configuring or serving the SMTP server fails.
bdac638883 2026-11-01 44: fn main () -> Result<()> {
bdac638883 2026-11-01 45: smol::block_on(async move{
ac6ac8c108 2026-09-25 46: let args = Args::parse();
42ac4c7a9a 2026-10-28 47: let settings = {
42ac4c7a9a 2026-10-28 48: // Load configuration defaults and overrides after checking file permissions.
42ac4c7a9a 2026-10-28 49: let config_file = Path::new(&args.config);
42ac4c7a9a 2026-10-28 50: if !config_file.try_exists().stack()? {
42ac4c7a9a 2026-10-28 51: bail!("Configuration file not found: {config_file:?}\n\
42ac4c7a9a 2026-10-28 52: Hint: Ensure the file exists and the path is correct.");
42ac4c7a9a 2026-10-28 53: };
42ac4c7a9a 2026-10-28 54: {
42ac4c7a9a 2026-10-28 55: let meta = metadata(config_file).await.stack()?;
42ac4c7a9a 2026-10-28 56: if (!0o100600 & meta.permissions().mode()) > 0 {
42ac4c7a9a 2026-10-28 57: bail!("Configuration file permissions are insecure {config_file:?}\n\
42ac4c7a9a 2026-10-28 58: Current permissions: {:o}\n\
42ac4c7a9a 2026-10-28 59: Required: 0600 (owner read/write only).\n\
42ac4c7a9a 2026-10-28 60: Fix with: chmod 600 {config_file:?}",
42ac4c7a9a 2026-10-28 61: meta.permissions().mode());
42ac4c7a9a 2026-10-28 62: } }
42ac4c7a9a 2026-10-28 63: config::Config::builder()
42ac4c7a9a 2026-10-28 64: .set_default("api_gateway", "https://api.telegram.org").stack()?
42ac4c7a9a 2026-10-28 65: .set_default("fields", vec!["date", "from", "subject"]).stack()?
42ac4c7a9a 2026-10-28 66: .set_default("hostname", "smtp.2.tg").stack()?
42ac4c7a9a 2026-10-28 67: .set_default("listen_on", "0.0.0.0:1025").stack()?
42ac4c7a9a 2026-10-28 68: .set_default("domains", vec!["localhost",
42ac4c7a9a 2026-10-28 69: hostname::get().context("Failed to get current hostname")?
42ac4c7a9a 2026-10-28 70: .to_str().context("Can't convert hostname to string, bad UTF-8?")?]).stack()?
42ac4c7a9a 2026-10-28 71: .add_source(config::File::from(config_file))
42ac4c7a9a 2026-10-28 72: .build()
42ac4c7a9a 2026-10-28 73: .with_context(|| format!(
42ac4c7a9a 2026-10-28 74: "Failed to parse configuration file: {config_file:?}\n\
42ac4c7a9a 2026-10-28 75: Check syntax against smtp2tg.toml.example.\n\
42ac4c7a9a 2026-10-28 76: Common issues: missing quotes, trailing commas in inline tables, or invalid types."
42ac4c7a9a 2026-10-28 77: ))?
ac6ac8c108 2026-09-25 78: };
ac6ac8c108 2026-09-25 79:
ac6ac8c108 2026-09-25 80: let listen_on = settings.get_string("listen_on").stack()?;
ac6ac8c108 2026-09-25 81: let server_name = settings.get_string("hostname").stack()?;
ac6ac8c108 2026-09-25 82: let core = MailServer::new(settings)?;
ac6ac8c108 2026-09-25 83: let mut server = mailin_embedded::Server::new(core);
ac6ac8c108 2026-09-25 84:
ac6ac8c108 2026-09-25 85: // TODO: remove unwraps when mailin-embedded bumps with better error handling
ac6ac8c108 2026-09-25 86: server.with_name(server_name)
ac6ac8c108 2026-09-25 87: .with_ssl(mailin_embedded::SslConfig::None).unwrap()
bdac638883 2026-11-01 88: .with_addr(listen_on).unwrap()
bdac638883 2026-11-01 89: .with_num_threads(1);
ac6ac8c108 2026-09-25 90: server.serve().unwrap();
ac6ac8c108 2026-09-25 91:
ac6ac8c108 2026-09-25 92: Ok(())
bdac638883 2026-11-01 93: })
bdac638883 2026-11-01 94: }