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cp: fix possible OOM and partial write with large files

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Szabó Attila 2024-09-13 08:14:14 +02:00 • committed by Ben Wiederhake
parent 6935a0d67e
commit 1781c3e07d
1 changed files with 14 additions and 18 deletions
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32
src/uu/cp/src/platform/linux.rs
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@ -141,6 +141,10 @@ where
} }
let src_fd = src_file.as_raw_fd(); let src_fd = src_file.as_raw_fd();
let mut current_offset: isize = 0; let mut current_offset: isize = 0;
// Maximize the data read at once to 16 MiB to avoid memory hogging with large files
// 16 MiB chunks should saturate an SSD
let step = std::cmp::min(size, 16 * 1024 * 1024) as usize;
let mut buf: Vec<u8> = vec![0x0; step];
loop { loop {
let result = unsafe { libc::lseek(src_fd, current_offset.try_into().unwrap(), SEEK_DATA) } let result = unsafe { libc::lseek(src_fd, current_offset.try_into().unwrap(), SEEK_DATA) }
.try_into() .try_into()
@ -158,16 +162,14 @@ where
return Err(std::io::Error::last_os_error()); return Err(std::io::Error::last_os_error());
} }
let len: isize = hole - current_offset; let len: isize = hole - current_offset;
let mut buf: Vec<u8> = vec![0x0; len as usize]; // Read and write data in chunks of `step` while reusing the same buffer
src_file.read_exact_at(&mut buf, current_offset as u64)?; for i in (0..len).step_by(step) {
unsafe { // Ensure we don't read past the end of the file or the start of the next hole
libc::pwrite( let read_len = std::cmp::min((len - i) as usize, step);
dst_fd, let buf = &mut buf[..read_len];
buf.as_ptr() as *const libc::c_void, src_file.read_exact_at(buf, (current_offset + i) as u64)?;
len as usize, dst_file.write_all_at(buf, (current_offset + i) as u64)?;
current_offset.try_into().unwrap(), }
)
};
current_offset = hole; current_offset = hole;
} }
Ok(()) Ok(())
@ -197,15 +199,9 @@ where
// https://www.kernel.org/doc/html/latest/filesystems/fiemap.html // https://www.kernel.org/doc/html/latest/filesystems/fiemap.html
while current_offset < size { while current_offset < size {
let this_read = src_file.read(&mut buf)?; let this_read = src_file.read(&mut buf)?;
let buf = &buf[..this_read];
if buf.iter().any(|&x| x != 0) { if buf.iter().any(|&x| x != 0) {
unsafe { dst_file.write_all_at(buf, current_offset.try_into().unwrap())?;
libc::pwrite(
dst_fd,
buf.as_ptr() as *const libc::c_void,
this_read,
current_offset.try_into().unwrap(),
)
};
} }
current_offset += this_read; current_offset += this_read;
} }