doc: More on what's special about the archive format.

* doc/guix.texi (Invoking guix archive): Expound on what sets the Nar
  format apart.
master
Ludovic Courtès 2014-02-21 20:22:57 +01:00
parent 96c7448f37
commit 0dbd88db39
1 changed files with 13 additions and 5 deletions

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@ -1095,11 +1095,19 @@ the target machine's store. The @code{--missing} option can help figure
out which items are missing from the target's store.
Archives are stored in the ``Nix archive'' or ``Nar'' format, which is
comparable in spirit to `tar'. When exporting, the daemon digitally
signs the contents of the archive, and that digital signature is
appended. When importing, the daemon verifies the signature and rejects
the import in case of an invalid signature or if the signing key is not
authorized.
comparable in spirit to `tar', but with a few noteworthy differences
that make it more appropriate for our purposes. First, rather than
recording all Unix meta-data for each file, the Nar format only mentions
the file type (regular, directory, or symbolic link); Unix permissions
and owner/group are dismissed. Second, the order in which directory
entries are stored always follows the order of file names according to
the C locale collation order. This makes archive production fully
deterministic.
When exporting, the daemon digitally signs the contents of the archive,
and that digital signature is appended. When importing, the daemon
verifies the signature and rejects the import in case of an invalid
signature or if the signing key is not authorized.
@c FIXME: Add xref to daemon doc about signatures.
The main options are: