From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate001.proxmox.com (gate001.proxmox.com [45.144.208.40]) by lore.proxmox.com (Postfix) with ESMTPS id 7C12F1FF0E4 for ; Tue, 14 Jul 2026 16:20:11 +0200 (CEST) Received: from gate001.proxmox.com (localhost.localdomain [127.0.0.1]) by gate001.proxmox.com (Proxmox) with ESMTP id E9A63213E9; Tue, 14 Jul 2026 16:20:10 +0200 (CEST) Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Tue, 14 Jul 2026 16:19:35 +0200 Message-Id: From: "Shan Shaji" To: =?utf-8?q?Fabian_Gr=C3=BCnbichler?= , Subject: Re: [PATCH proxmox-backup] fix #5748: docs: add `catalog.pcat1` format specification X-Mailer: aerc 0.20.0 References: <20260702115115.195035-1-s.shaji@proxmox.com> <1784019611.wtdtzouh6v.astroid@yuna.none> In-Reply-To: <1784019611.wtdtzouh6v.astroid@yuna.none> X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1784038759693 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.205 Adjusted score from AWL reputation of From: address DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment (newer systems) RCVD_IN_DNSWL_LOW -0.7 Sender listed at https://www.dnswl.org/, low trust SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Message-ID-Hash: N5ICHPSWOS6RQOUJEM6DLIPR7RDXOBGO X-Message-ID-Hash: N5ICHPSWOS6RQOUJEM6DLIPR7RDXOBGO X-MailFrom: s.shaji@proxmox.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list List-Id: Proxmox Backup Server development discussion List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Tue Jul 14, 2026 at 11:38 AM CEST, Fabian Gr=C3=BCnbichler wrote: > On July 2, 2026 1:51 pm, Shan Shaji wrote: >> Earlier proxmox catalog file format specification was not present >> inside the docs. fixed it by adding format specification under file >> formats. >>=20 >> Fixes: https://bugzilla.proxmox.com/show_bug.cgi?id=3D5748 >> Signed-off-by: Shan Shaji >> --- >> changes since RFC: Thanks @Christian Ebner >> - Changed from graph to table layout. >> - Explicity mention about the variable length types.=20 >> - Denoted the root start offset as u64. >> - Add text description for each field. >> =20 >> docs/file-formats.rst | 65 +++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 65 insertions(+) >>=20 >> diff --git a/docs/file-formats.rst b/docs/file-formats.rst >> index ed3250d11..52cb20ee0 100644 >> --- a/docs/file-formats.rst >> +++ b/docs/file-formats.rst >> @@ -23,6 +23,71 @@ overhead introduced by the file payloads. >> =20 >> .. graphviz:: meta-format-overview.dot >> =20 >> +.. _pcat1-format: >> + >> +Proxmox Catalog File Format (``.pcat1``) >> +---------------------------------------- > > this should go between pxar and mpxar, or below ppxar. there's arguments > for both, but between mpxar and ppxar which always form a pair and never > use catalog files is the wrong place ;) makes sense, I will update it.=20 >> + >> +The asterisk notation indicates variable-length encoding: u64* denotes = an unsigned variable-length encoded integer, while i64* >> +denotes a signed variable-length encoded integer. > > it would be nice to describe the encoding here as well, after all this > part of the docs is supposed to help understand how to parse such a > file. I will add that, thank you! Do you think a description explaining how we en= code it would be enough? >> + >> +.. list-table:: >> + :widths: auto >> + >> + * - ``MAGIC: [u8; 8]`` >> + - ``[145, 253, 96, 249, 196, 103, 88, 213]``. >> + * - ``TABLE_LENGTH: u64*`` >> + - Total length of the contents inside the Directory. >> + * - ``ENTRY_COUNT: u64*`` >> + - Count of entries present inside the Directory. >> + * - ``ENTRIES`` >> + - Concatinated ``ENTRY`` structures (see the ``ENTRY`` :ref:`layou= t ` .) Repeated ``ENTRY_COUNT`` times. > > concatenated Thank you, I will update it. >> + * - ... >> + - Further concatination of sequential directory blocks (Table Leng= th, Entry Count and Entries). > > concatenation > > what makes directory blocks "sequential"? What I meant was like, the table length, number of entries and the data byt= es are written sequentially. Now that I think about it, I think it is wrong. The reader could misinterpret it and think that the file can be read sequential= ly. Thank you! |foo2_info|dir3_info|dir2_info|dir1_info|/ > >> + * - ``ROOT_START_OFFSET: u64`` >> + - Root marker (/) start offset. Stored as **little-endian** > > the root marker is very important, as it points at the offset of the > directory where somebody parsing this file needs to start doing > recursive lookups.. > > so maybe this should actually be > > MAGIC > [catalog data] > ROOT_START_OFFSET > > where ROOT_START_OFFSET points at the start of the '/' catalog entry > > and then we have > > catalog entry: Did you meant catalog data here? In the above suggestion you mentioned catalog data between the MAGIC and the root start offset. =20 >> + * - ``TABLE_LENGTH: u64*`` >> + - Total length of the catalog contents of this Directory. >> + * - ``ENTRY_COUNT: u64*`` >> + - Count of directory entries >> + * - ``ENTRIES`` >> + - Concatenated ``ENTRY`` structures (see the ``ENTRY`` :ref:`layou= t ` .), repeated ``ENTRY_COUNT`` times. > >> + >> +.. _entry-layout: >> + >> +Except for files and directories, no additional payload is stored beyon= d the name and its length inside an ENTRY. >> + >> +.. list-table:: >> + :widths: auto >> + >> + * - ``ENTRY_TYPE: u8`` >> + - The type of entry (see entry :ref:`types `). >> + * - ``NAME_LENGTH: u64*`` >> + - Length of file or directory name. Stored as variable length enco= ded u64. >> + * - ``NAME: [u8]`` >> + - The raw UTF-8 string bytes of the name. >> + * - ``PAYLOAD`` >> + - Bytes based on ``ENTRY_TYPE`` >> + >> + * **Directory ('d')**: ``offset_back: u64*`` (Child-to-Parent of= fset distance) > > the offset back probably requires more explanation I will update it. Thank you! >> + * **File ('f')**: ``size: u64*`` followed by ``mtime: i64*`` >> +.. _entry-types: >> + >> +Entry Types: >> + >> +.. list-table:: >> + :widths: auto >> + >> + * - ``d`` >> + - Directory >> + * - ``f`` >> + - File >> + * - ``l`` >> + - Symlink >> + * - ``h`` >> + - Hardlink >> + * - ``b`` >> + - Block device >> + * - ``c`` >> + - Char device >> + * - ``p`` >> + - FIFO >> + * - ``s`` >> + - Socket >> .. _ppxar-format: >> =20 >> Proxmox File Archive Format - Payload (``.ppxar``) >> --=20 >> 2.47.3 >>=20 >>=20 >>=20 >>=20 >>=20 >>=20