52 lines
2.0 KiB
Rust
52 lines
2.0 KiB
Rust
use std::{
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env::args,
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fs::File,
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io::{self, Write},
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path::Path,
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};
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const BLOCK_SIZE: u16 = 512;
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const MAX_NAME_LEN: u16 = BLOCK_SIZE - 8;
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fn main() {
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let mut archive = File::create("initrd").expect("Could not open initrd");
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for file_path in args().skip(1) {
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let file_path = Path::new(&file_path);
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let file_name = file_path.file_name().unwrap();
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let file_name_len =
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u16::try_from(file_name.len()).expect("File name length greater than 256 bytes");
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assert!(
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file_name_len <= MAX_NAME_LEN,
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"File {:?} has name longer than {} bytes",
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file_name,
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MAX_NAME_LEN
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);
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let mut file = File::open(file_path).expect("File did not exist");
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let length = u16::try_from(file.metadata().expect("Could not get file metadata").len())
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.expect("File size greater than 64 KiB");
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let file_num_blocks = (length / BLOCK_SIZE) + if length % BLOCK_SIZE == 0 { 0 } else { 1 };
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let mut header_block = Vec::new();
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header_block.extend_from_slice(&length.to_be_bytes());
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header_block.extend_from_slice(&file_num_blocks.to_be_bytes());
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header_block.extend_from_slice(&file_name_len.to_be_bytes());
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header_block.extend_from_slice(file_name.to_str().unwrap().as_bytes());
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header_block.push(0);
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header_block.resize(BLOCK_SIZE as usize, 0);
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archive
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.write_all(&header_block)
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.expect("Could not write to initrd");
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#[allow(clippy::cast_possible_truncation)]
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let bytes_written = io::copy(&mut file, &mut archive)
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.expect("Could not read from file/write to initrd") as u16;
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if (bytes_written % BLOCK_SIZE) != 0 {
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let bytes_padding = (BLOCK_SIZE) - (bytes_written % BLOCK_SIZE);
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for _ in 0..bytes_padding {
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archive.write_all(&[0]).expect("Could not write to initrd");
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}
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}
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}
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archive
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.write_all(&[0; BLOCK_SIZE as usize])
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.expect("Could not write to initrd");
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}
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