Module export 

APIs for creating container images from OSTree commits

Structs

ExportOptions

Configuration for tar export.

OstreeTarWriter 🔒

Constants

BARE_SPLIT_XATTRS_MODE

The repository mode generated by a tar export stream.

BUF_CAPACITY 🔒

A decently large buffer, as used by e.g. coreutils cat. System calls are expensive.

OSTREEDIR 🔒

OSTREEREF 🔒

REPO_CONFIG 🔒

The base repository configuration that identifies this is a tar export.

SECURITY_SELINUX_XATTR 🔒

Then derive a string version (without the NUL) from the above.

SECURITY_SELINUX_XATTR_C 🔒

The SELinux xattr. Because the ostree xattrs require an embedded NUL, we store that version as a constant.

SYSROOT 🔒

TAR_PATH_PREFIX_V0 🔒

In v0 format, we use this relative path prefix. I think I chose this by looking at the current Fedora base image tar stream. However, several others don’t do this and have paths be relative by simply omitting ./, i.e. the tar stream contains usr/bin/bash and not ./usr/bin/bash. The former looks cleaner to me, so in v1 we drop it.

Functions

append_pax_xattrs 🔒

Append xattrs to the tar stream as PAX extensions, excluding security.selinux which doesn’t become visible in container runtimes anyway. https://github.com/containers/storage/blob/0d4a8d2aaf293c9f0464b888d932ab5147a284b9/pkg/archive/archive.go#L85

export_chunk 🔒

Output a chunk to a tar stream.

export_commit

Export an ostree commit to an (uncompressed) tar archive stream.

export_final_chunk 🔒

Output the last chunk in a chunking.

impl_export 🔒

Recursively walk an OSTree commit and generate data into a [tar::Builder] which contains all of the metadata objects, as well as a hardlinked stream that looks like a checkout. Extended attributes are stored specially out of band of tar so that they can be reliably retrieved.

impl_raw_export 🔒

Export an ostree commit as a “raw” tar stream - just the filesystem content with /usr/etc -> /etc remapping, without ostree repository structure.

map_path 🔒

Convert /usr/etc back to /etc

map_path_inner 🔒

Convert from to to

map_path_v1 🔒

Convert usr/etc back to etc for the tar stream.

object_path 🔒

path_equivalent_for_tar 🔒

Given two paths, which may be absolute (starting with /) or start with ./, return true if they are equal after removing those prefixes. This is effectively “would these paths be equal” when processed as a tar entry.

path_for_tar_v1 🔒

Chunked (or version 1) tar streams don’t have a leading ./.

raw_export_dir 🔒

Recursively export a directory for raw export mode.

reinject_detached_metadata 🔒

Process an exported tar stream, and update the detached metadata.

symlink_is_denormal 🔒

Check for “denormal” symlinks which contain “//”

tar_append_default_data 🔒

unmap_path 🔒

Convert etc to usr/etc Note: no leading ‘/’ or ‘./’

update_detached_metadata

Replace the detached metadata in an tar stream which is an export of an OSTree commit.

v1_xattrs_object_path 🔒

write_chunk 🔒

Implementation of chunk writing, assumes that the preliminary structure has been written to the tar stream.