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move src/pxar.rs -> src/pxar/mod.rs

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Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
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Wolfgang Bumiller
2020-06-09 10:49:43 +02:00
parent 9bb161c881
commit 2179359f40
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src/pxar/mod.rs Normal file
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//! *pxar* Implementation (proxmox file archive format)
//!
//! This code implements a slightly modified version of the *catar*
//! format used in the [casync](https://github.com/systemd/casync)
//! toolkit (we are not 100\% binary compatible). It is a file archive
//! format defined by 'Lennart Poettering', specially defined for
//! efficient deduplication.
//! Every archive contains items in the following order:
//! * `ENTRY` -- containing general stat() data and related bits
//! * `USER` -- user name as text, if enabled
//! * `GROUP` -- group name as text, if enabled
//! * `XATTR` -- one extended attribute
//! * ... -- more of these when there are multiple defined
//! * `ACL_USER` -- one `USER ACL` entry
//! * ... -- more of these when there are multiple defined
//! * `ACL_GROUP` -- one `GROUP ACL` entry
//! * ... -- more of these when there are multiple defined
//! * `ACL_GROUP_OBJ` -- The `ACL_GROUP_OBJ`
//! * `ACL_DEFAULT` -- The various default ACL fields if there's one defined
//! * `ACL_DEFAULT_USER` -- one USER ACL entry
//! * ... -- more of these when multiple are defined
//! * `ACL_DEFAULT_GROUP` -- one GROUP ACL entry
//! * ... -- more of these when multiple are defined
//! * `FCAPS` -- file capability in Linux disk format
//! * `QUOTA_PROJECT_ID` -- the ext4/xfs quota project ID
//! * `PAYLOAD` -- file contents, if it is one
//! * `SYMLINK` -- symlink target, if it is one
//! * `DEVICE` -- device major/minor, if it is a block/char device
//!
//! If we are serializing a directory, then this is followed by:
//!
//! * `FILENAME` -- name of the first directory entry (strictly ordered!)
//! * `<archive>` -- serialization of the first directory entry's metadata and contents,
//! following the exact same archive format
//! * `FILENAME` -- name of the second directory entry (strictly ordered!)
//! * `<archive>` -- serialization of the second directory entry
//! * ...
//! * `GOODBYE` -- lookup table at the end of a list of directory entries
//!
//! The original format has no way to deal with hardlinks, so we
//! extended the format by a special `HARDLINK` tag, which can replace
//! an `ENTRY` tag. The `HARDLINK` tag contains an 64bit offset which
//! points to the linked `ENTRY` inside the archive, followed by the
//! full path name of that `ENTRY`. `HARDLINK`s may not have further data
//! (user, group, acl, ...) because this is already defined by the
//! linked `ENTRY`.
pub mod catalog;
pub(crate) mod create;
pub(crate) mod dir_stack;
pub(crate) mod extract;
pub(crate) mod metadata;
pub mod flags;
pub mod fuse;
pub(crate) mod tools;
pub use create::create_archive;
pub use extract::extract_archive;
/// The format requires to build sorted directory lookup tables in
/// memory, so we restrict the number of allowed entries to limit
/// maximum memory usage.
pub const ENCODER_MAX_ENTRIES: usize = 1024 * 1024;
pub use tools::{format_multi_line_entry, format_single_line_entry};