63 lines
1.6 KiB
Rust
63 lines
1.6 KiB
Rust
use std::thread;
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use std::path::PathBuf;
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use std::io::Write;
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use anyhow::{bail, Error};
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// tar handle files that shrink during backup, by simply padding with zeros.
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//
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// this binary run multiple thread which writes some large files, then truncates
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// them in a loop.
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// # tar cf test.tar ./dyntest1/
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// tar: dyntest1/testfile0.dat: File shrank by 2768972800 bytes; padding with zeros
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// tar: dyntest1/testfile17.dat: File shrank by 2899853312 bytes; padding with zeros
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// tar: dyntest1/testfile2.dat: File shrank by 3093422080 bytes; padding with zeros
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// tar: dyntest1/testfile7.dat: File shrank by 2833252864 bytes; padding with zeros
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// # pxar create test.pxar ./dyntest1/
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// Error: detected shrunk file "./dyntest1/testfile0.dat" (22020096 < 12679380992)
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fn create_large_file(path: PathBuf) {
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println!("TEST {:?}", path);
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let mut file = std::fs::OpenOptions::new()
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.write(true)
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.create_new(true)
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.open(&path).unwrap();
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let buffer = vec![0u8; 64*1024];
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loop {
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for _ in 0..64 {
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file.write_all(&buffer).unwrap();
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}
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file.sync_all().unwrap();
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//println!("TRUNCATE {:?}", path);
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file.set_len(0).unwrap();
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}
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}
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fn main() -> Result<(), Error> {
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let base = PathBuf::from("dyntest1");
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let _ = std::fs::create_dir(&base);
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let mut handles = vec![];
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for i in 0..20 {
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let base = base.clone();
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handles.push(thread::spawn(move || {
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create_large_file(base.join(format!("testfile{}.dat", i)));
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}));
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}
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for h in handles {
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if h.join().is_err() {
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bail!("join failed");
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}
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}
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Ok(())
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}
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