src/catar/format_definition.rs

   1 //! *catar* binary format definition
   2 //!
   3 //! Please note the all values are stored in little endian ordering.
   4 //!
   5 //! The Archive contains a list of items. Each item starts with a
   6 //! `CaFormatHeader`, followed by the item data.
   7
   8 use failure::*;
   9
  10 use siphasher::sip::SipHasher24;
  11
  12 pub const CA_FORMAT_ENTRY: u64 = 0x1396fabcea5bbb51;
  13 pub const CA_FORMAT_FILENAME: u64 = 0x6dbb6ebcb3161f0b;
  14 pub const CA_FORMAT_SYMLINK: u64 = 0x664a6fb6830e0d6c;
  15 pub const CA_FORMAT_PAYLOAD: u64 = 0x8b9e1d93d6dcffc9;
  16
  17 pub const CA_FORMAT_GOODBYE: u64 = 0xdfd35c5e8327c403;
  18 /* The end marker used in the GOODBYE object */
  19 pub const CA_FORMAT_GOODBYE_TAIL_MARKER: u64 = 0x57446fa533702943;
  20
  21 pub const CA_FORMAT_FEATURE_FLAGS_MAX: u64 = 0xb000_0001_ffef_fe26; // fixme: ?
  22
  23 #[repr(C)]
  24 pub struct CaFormatHeader {
  25     /// The size of the item, including the size of `CaFormatHeader`.
  26     pub size: u64,
  27     /// The item type (see `CA_FORMAT_` constants).
  28     pub htype: u64,
  29 }
  30
  31 #[repr(C)]
  32 pub struct CaFormatEntry {
  33     pub feature_flags: u64,
  34     pub mode: u64,
  35     pub flags: u64,
  36     pub uid: u64,
  37     pub gid: u64,
  38     pub mtime: u64,
  39 }
  40
  41 #[repr(C)]
  42 pub struct CaFormatGoodbyeItem {
  43     /// The offset from the start of the GOODBYE object to the start
  44     /// of the matching directory item (point to a FILENAME). The last
  45     /// GOODBYE item points to the start of the matching ENTRY
  46     /// object. repeats the `size`
  47     pub offset: u64,
  48     /// The overall size of the directory item. The last GOODBYE item
  49     /// repeats the size of the GOODBYE item.
  50     pub size: u64,
  51     /// SipHash24 of the directory item name. The last GOODBYE item
  52     /// uses the special hash value `CA_FORMAT_GOODBYE_TAIL_MARKER`.
  53     pub hash: u64,
  54 }
  55
  56
  57 /// Helper function to extract file names from binary archive.
  58 pub fn read_os_string(buffer: &[u8]) -> std::ffi::OsString {
  59     let len = buffer.len();
  60
  61     use std::os::unix::ffi::OsStrExt;
  62
  63     let name = if len > 0 && buffer[len-1] == 0 {
  64         std::ffi::OsStr::from_bytes(&buffer[0..len-1])
  65     } else {
  66         std::ffi::OsStr::from_bytes(&buffer)
  67     };
  68
  69     name.into()
  70 }
  71
  72 /// Create SipHash values for goodby tables.
  73 //pub fn compute_goodbye_hash(name: &std::ffi::CStr) -> u64 {
  74 pub fn compute_goodbye_hash(name: &[u8]) -> u64 {
  75
  76     use std::hash::Hasher;
  77     let mut hasher = SipHasher24::new_with_keys(0x8574442b0f1d84b3, 0x2736ed30d1c22ec1);
  78     hasher.write(name);
  79     hasher.finish()
  80 }