lix/nix-rust/src/lib.rs
Eelco Dolstra 045708db43 Make <nix/unpack-channel.nix> a builtin builder
This was the last function using a shell script, so this allows us to
get rid of tar, coreutils, bash etc.
2019-11-26 22:07:28 +01:00

67 lines
1.9 KiB
Rust

extern crate libc;
extern crate tar;
use std::fs;
use std::io;
use std::os::unix::fs::OpenOptionsExt;
use std::path::Path;
use tar::Archive;
/// A wrapper around Nix's Source class that provides the Read trait.
#[repr(C)]
pub struct Source {
fun: extern "C" fn(this: *mut libc::c_void, data: &mut [u8]) -> usize,
this: *mut libc::c_void,
}
impl std::io::Read for Source {
fn read(&mut self, buf: &mut [u8]) -> std::result::Result<usize, std::io::Error> {
let n = (self.fun)(self.this, buf);
assert!(n <= buf.len());
Ok(n)
}
}
#[no_mangle]
pub extern "C" fn unpack_tarfile(source: Source, dest_dir: &str) -> bool {
// FIXME: handle errors.
let dest_dir = Path::new(dest_dir);
let mut tar = Archive::new(source);
for file in tar.entries().unwrap() {
let mut file = file.unwrap();
let dest_file = dest_dir.join(file.path().unwrap());
fs::create_dir_all(dest_file.parent().unwrap()).unwrap();
match file.header().entry_type() {
tar::EntryType::Directory => {
fs::create_dir(dest_file).unwrap();
}
tar::EntryType::Regular => {
let mode = if file.header().mode().unwrap() & libc::S_IXUSR == 0 {
0o666
} else {
0o777
};
let mut f = fs::OpenOptions::new()
.create(true)
.write(true)
.mode(mode)
.open(dest_file)
.unwrap();
io::copy(&mut file, &mut f).unwrap();
}
tar::EntryType::Symlink => {
std::os::unix::fs::symlink(file.header().link_name().unwrap().unwrap(), dest_file).unwrap();
}
t => panic!("Unsupported tar entry type '{:?}'.", t),
}
}
true
}