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//! Select functionality from [assuan-socket.c].
//!
//! [assuan-socket.c]: https://github.com/gpg/libassuan/blob/master/src/assuan-socket.c
use std::io;
use std::path::Path;
use crate::Result;
#[derive(Debug)]
pub(crate) struct Rendezvous {
port: u16,
socket_kind: SocketKind,
nonce: [u8; 16],
}
#[derive(Debug)]
pub(crate) enum SocketKind {
Cygwin,
Emulated
}
pub(crate) fn read_port_and_nonce(fname: &Path) -> Result<Rendezvous> {
let contents = std::fs::read_to_string(fname)?;
read_port_and_nonce_from_string(&contents)
}
fn read_port_and_nonce_from_string(contents: &str) -> Result<Rendezvous> {
match contents.strip_prefix("!<socket >") {
// libassuan's Cygwin compatible socket emulation.
// Format: "!<socket >%u %c %08x-%08x-%08x-%08x\x00" (scanf-like)
Some(buf) => {
let opt_skip_nul = buf.strip_suffix("\x00").unwrap_or(buf);
// Split into parts: port, kind of socket and nonce
let mut iter = opt_skip_nul.split_terminator(' ');
match (iter.next(), iter.next(), iter.next()) {
(Some(port), Some("s"), Some(nonce)) => {
let port = port.parse()?;
let socket_kind = SocketKind::Cygwin;
// This is wasteful but an allocation-free alternative is even
// more verbose and it's not enough to pull a hex parser dep.
let nonce_chunks = nonce.split_terminator('-')
.map(|dword| u32::from_str_radix(dword, 16).map_err(Into::into))
.collect::<Result<Vec<_>>>();
let nonce = match nonce_chunks.ok().as_deref() {
Some(&[d0, d1, d2, d3, ..]) => {
let mut nonce = [0u8; 16];
nonce[0..4].copy_from_slice(&d0.to_ne_bytes());
nonce[4..8].copy_from_slice(&d1.to_ne_bytes());
nonce[8..12].copy_from_slice(&d2.to_ne_bytes());
nonce[12..16].copy_from_slice(&d3.to_ne_bytes());
nonce
},
_ => return Err(anyhow::anyhow!("Couldn't parse Cygwin socket nonce: {}", contents)),
};
Ok(Rendezvous { port, nonce, socket_kind })
},
_ => return Err(anyhow::anyhow!("Couldn't parse Cygwin socket: {}", contents)),
}
},
// libassuan's own socket emulation
// Format: [<whitespace>?, port, .., '\n', <16 byte nonce>]
None => {
let pos = match contents.as_bytes().iter().position(|&x| x == b'\n') {
// Also ensure that there are exactly 16 bytes following
Some(pos) if pos + 1 + 16 == contents.len() => pos,
_ => return Err(anyhow::anyhow!("Malformed socket description: {}", contents)),
};
let port = contents[..pos].trim().parse()?;
let mut nonce = [0u8; 16];
nonce[..].copy_from_slice(&contents.as_bytes()[pos + 1..]);
let socket_kind = SocketKind::Emulated;
Ok(Rendezvous { port, nonce, socket_kind: SocketKind::Emulated })
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn read_port_and_nonce_from_files() -> Result<()> {
let test_fn = read_port_and_nonce_from_string;
assert!(test_fn("\t 12 \n1234567890123456").is_ok());
assert!(test_fn("\t 12 \n123456789012345").is_err());
assert!(test_fn("\t 12 \n12345678901234567").is_err());
assert!(matches!(
test_fn(" 12345\n\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F"),
Ok(Rendezvous {
port: 12345,
socket_kind: SocketKind::Emulated,
nonce: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15],
})
));
assert!(matches!(
test_fn(" -152\n\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F"),
Err(..)
));
assert!(matches!(
test_fn("!<socket >12345 s AABBCCDD-DDCCBBAA-01234567-890ABCDE\x00"),
Ok(Rendezvous {
port: 12345,
socket_kind: SocketKind::Cygwin,
nonce: [
0xDD, 0xCC, 0xBB, 0xAA,
0xAA, 0xBB, 0xCC, 0xDD,
0x67, 0x45, 0x23, 0x01,
0xDE, 0xBC, 0x0A, 0x89,
]
})
));
assert!(matches!(
test_fn("!<socket >12345 s AABBCCDD-DDCCBBAA-01234567-890ABCDE"),
Ok(Rendezvous {
port: 12345,
socket_kind: SocketKind::Cygwin,
nonce: [
0xDD, 0xCC, 0xBB, 0xAA,
0xAA, 0xBB, 0xCC, 0xDD,
0x67, 0x45, 0x23, 0x01,
0xDE, 0xBC, 0x0A, 0x89,
]
})
));
Ok(())
}
}
|
