pbs-datastore/src/checksum_writer.rs

   1 use std::sync::Arc;
   2 use std::io::Write;
   3
   4 use anyhow::{Error};
   5
   6 use proxmox_borrow::Tied;
   7
   8 use pbs_tools::crypt_config::CryptConfig;
   9
  10 pub struct ChecksumWriter<W> {
  11     writer: W,
  12     hasher: crc32fast::Hasher,
  13     signer: Option<Tied<Arc<CryptConfig>, openssl::sign::Signer<'static>>>,
  14 }
  15
  16 impl <W: Write> ChecksumWriter<W> {
  17
  18     pub fn new(writer: W, config: Option<Arc<CryptConfig>>) -> Self {
  19         let hasher = crc32fast::Hasher::new();
  20         let signer = match config {
  21             Some(config) => {
  22                 let tied_signer = Tied::new(config, |config| {
  23                     Box::new(unsafe { (*config).data_signer() })
  24                 });
  25                 Some(tied_signer)
  26             }
  27             None => None,
  28         };
  29         Self { writer, hasher, signer }
  30     }
  31
  32     pub fn finish(mut self) -> Result<(W, u32, Option<[u8; 32]>), Error> {
  33         let crc = self.hasher.finalize();
  34
  35         if let Some(ref mut signer) = self.signer {
  36             let mut tag = [0u8; 32];
  37             signer.sign(&mut tag)?;
  38             Ok((self.writer, crc, Some(tag)))
  39         } else {
  40             Ok((self.writer, crc, None))
  41         }
  42     }
  43 }
  44
  45 impl <W: Write> Write for ChecksumWriter<W> {
  46
  47     fn write(&mut self, buf: &[u8]) -> Result<usize, std::io::Error> {
  48         self.hasher.update(buf);
  49         if let Some(ref mut signer) = self.signer {
  50             signer.update(buf)
  51                 .map_err(|err| {
  52                     std::io::Error::new(
  53                         std::io::ErrorKind::Other,
  54                         format!("hmac update failed - {}", err))
  55                 })?;
  56         }
  57         self.writer.write(buf)
  58     }
  59
  60     fn flush(&mut self) -> Result<(), std::io::Error> {
  61         self.writer.flush()
  62     }
  63 }