freecalypso-tools: doc/TIFFS-old-description annotate

annotate doc/TIFFS-old-description @ 1013:bc4dc383ff4a default tip

doc/Loadtools-usage: list SE J110/120 pair properly These two Chi-Mei phones are variants of the same design with only minor diffs.

author	Mychaela Falconia <falcon@freecalypso.org>
date	Mon, 23 Sep 2024 12:28:57 +0000
parents	e7502631a0f9
children

rev	line source
0 e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	1 The description of TIFFS that follows was originally written in the summer of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	2 SE52 (A.D. 2013), before the major TI source discoveries which happened later
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	3 that year. The text following the dividing line below has not been edited in
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	4 content since it was written; for a newer write-up based on the current source-
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	5 enabled understanding and reflecting the current FreeCalypso plans with respect
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	6 to this FFS, see TIFFS-Overview.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	7
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	8 -------------------------------------------------------------------------------
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	9
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	10 This is a description, based on reverse engineering, of the flash file system
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	11 (FFS) implemented in Pirelli's original firmware for the DP-L10 GSM/WiFi dual
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	12 mode mobile phone, and in the Closedmoko GTA0x modem firmware. Not knowing the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	13 "proper" name for this FFS, and needing _some_ identifier to refer to it, I
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	14 have named it Mokopir-FFS, from "Moko" and "Pirelli" - sometimes abbreviated
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	15 further to MPFFS.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	16
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	17 (I have previously called the FFS in question MysteryFFS; but now that I've
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	18 successfully reverse-engineered it, it isn't as much of a mystery any more :-)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	19
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	20 At a high functional level, Mokopir-FFS presents the following features:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	21
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	22 * Has a directory tree structure like UNIX file systems;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	23
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	24 * The file system API that must be implemented inside the proprietary firmware
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	25 appears to use UNIX-style pathnames; doing strings on firmware images reveals
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	26 pathname strings like these:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	27
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	28 /var/dbg/dar
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	29 /gsm/l3/rr_white_list
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	30 /gsm/l3/rr_medium_rxlev_thr
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	31 /gsm/l3/rr_upper_rxlev_thr
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	32 /gsm/l3/shield
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	33
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	34 Parsing the corresponding FFS image with tools included in the present
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	35 package has confirmed that the directory structure implied by these pathnames
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	36 does indeed exist in the FFS.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	37
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	38 * Absolutely no DOS-ish semantics seen anywhere: no 8.3 filenames and no
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	39 colon-separated device names (seen in the TSM30 file system source, for
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	40 example) are visible in the Closedmoko/Pirelli FFS.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	41
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	42 * File contents are stored uncompressed, but not necessarily contiguous: one
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	43 could probably store a file in FFS which is bigger than the flash sector
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	44 size, it which case it can never be contiguous in a writable FFS (see below),
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	45 and the firmware implementation seems to limit chunk sizes to a fairly small
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	46 number: on the Pirelli phones all largish files are divided into chunks of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	47 8 KiB each, and on my GTA02 the largest observed chunk size is only 2 KiB.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	48
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	49 The smaller files, like the IMEI and the firmware ID strings in my GTA02 FFS,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	50 are contiguous.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	51
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	52 * The FFS structure is such that the length of "user" payload data stored in
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	53 each chunk (and consequently, in each file) can be known exactly in bytes,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	54 with the files/chunks able to contain arbitrary binary data. (This property
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	55 may seem obvious or trivial, as all familiar UNIX and DOS file systems have
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	56 it, but contrast with RT-11 for example.)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	57
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	58 * The flash file system is a writable one: the running firmware can create,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	59 delete and overwrite files (and possibly directories too) in the live FFS;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	60 thus the FFS design is such that allows these operations to be performed
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	61 within the physical constraints of NOR flash write operations.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	62
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	63 I have reverse-engineered this Mokopir-FFS on a read-only level. What it means
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	64 is that I, or anyone else who can read this document and the accompanying
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	65 source for the listing/extraction utilities, can take a Mokopir-FFS image read
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	66 out of a device and see/extract its full content: the complete directory tree
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	67 and the exact binary byte content of all files contained therein.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	68
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	69 However, the knowledge possessed by the present hacker (and conveyed in this
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	70 document and the accompanying source code) is NOT sufficient for constructing a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	71 valid Mokopir-FFS image "in vitro" given a tree of directories and files, or
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	72 for making modifications to the file or directory content of an existing image
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	73 and producing a content-modified image that is also valid; valid as in suitable
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	74 for the original proprietary firmware to make its normal read and write
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	75 operations without noticing anything amiss.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	76
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	77 Constructing "de novo" Mokopir-FFS images or modifying existing images in such
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	78 a way that they remain 100% valid for all read and write operations of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	79 original proprietary firmware would, at the very minimum, require an
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	80 understanding of the meaning of all fields of the on-media FFS format. Some
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	81 of these fields are still left as "non-understood" for now though: a read-only
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	82 implementation can get away with simply ignoring them, but a writer/generator
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	83 would have to put something in those fields.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	84
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	85 As you read the "read-only" description of the Mokopir-FFS on-media format in
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	86 the remainder of this document, it should become fairly obvious which pieces
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	87 are missing before our understanding of this FFS can be elevated to a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	88 "writable" level.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	89
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	90 However, when it comes to writing new code to run on the two Calypso phones in
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	91 question (Closedmoko and Pirelli), it seems, at least to the present hacker,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	92 that a read-only understanding of Mokopir-FFS should be sufficient:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	93
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	94 * In the case of Closedmoko GTA0x modems, the FFS is seen to contain the IMEI
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	95 and the RF calibration data. The format of the former is obvious; the latter
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	96 not so much - but in any case, the information of interest is clearly of a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	97 read-only nature. It's difficult to tell (or rather, I haven't bothered to
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	98 experiment enough) whether the Closedmoko firmware does any writes to FFS or
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	99 if the FFS is treated as read-only outside of the production line environment,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	100 but in any case, it seems to me that for any 3rd party replacement firmware,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	101 the best strategy would be to treat the FFS as a read-only source of IMEI and
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	102 RF calibration data, and nothing more.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	103
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	104 * In the case of Pirelli phones, the FFS is used to store user data: sent and
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	105 received SMS (and MMS/email/whatever), call history, UI settings, pictures
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	106 taken with the camera, and whatever else. It also stores a ton of files
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	107 which I can only presume were meant to be immutable except at the time of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	108 firmware updates: graphics for the UI, ringtones, i18n UI strings, and even
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	109 "helper" firmware images for the WiFi and VoIP processors. However, no IMEI
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	110 or RF calibration data are anywhere to be found in the FFS - instead this
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	111 information appears to be stored in the "factory block" at the end of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	112 flash (in its own sector) outside of the FFS.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	113
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	114 Being able to parse FFS images extracted out of Pirelli phones "in vitro"
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	115 allows us to steal some of these helper files (UI artwork, ringtones,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	116 WiFi/VoIP helpers), and some of these might even come useful to firmware
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	117 replacement projects, but it seems to me that a replacement firmware would
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	118 be better off using its own FFS design for storing user data, and as to
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	119 retrieving the original IMEI and RF calibration data, the original FFS isn't
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	120 of any use for that anyway.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	121
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	122 =======================
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	123 Moko/Pirelli FFS format
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	124 =======================
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	125
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	126 OK, now that I'm done with the introduction, we can get to the actual
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	127 Mokopir-FFS format.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	128
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	129 * On the GTA0x modem (or at least on my GTA02; my sample size is 1) the FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	130 occupies 7 flash sectors of 64 KiB each at offsets 0x380000 through 0x3E0000,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	131 inclusive.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	132
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	133 (The 4 MiB NOR flash chip used by Closedmoko has an independent R/W bank
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	134 division between the first 3 MiB and the last 1 MiB. The first 3 MiB are used
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	135 to hold the field-flashable closed firmware images distributed as *.m0 files;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	136 the independent last megabyte holds the FFS, and thus the FW could be
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	137 implemented to do FFS writes while running from flash in the main bank.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	138 Less than half of that last megabyte appears to be used for the FFS though;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	139 the rest appears to be unused - blank flash observed.)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	140
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	141 * On the Pirelli the FFS occupies 18 sectors of 256 KiB each at offsets 0
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	142 through 0x440000 (inclusive) of the 2nd flash chip select, the one wired to
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	143 nCS3 on the Calypso.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	144
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	145 Each flash sector allocated to FFS begins with the following signature:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	146
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	147 00000000: 46 66 73 23 10 02 xx yy zz FF FF FF FF FF FF FF Ffs#............
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	148
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	149 The bytes shown as xx and yy above serve a non-understood purpose; as a guess,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	150 they may hold some info for the flash wear leveling algorithm: in a "virgin"
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	151 FFS image like that found in my GTA02 (which never had a SIM card in it and
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	152 never made or received a call) or read out of a "virgin" Pirelli phone that
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	153 hasn't seen any active use yet, both of these bytes are FFs, but when I look at
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	154 FFS images read out of the Pirelli which I currently use as my everyday-use
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	155 cellphone, I see other values in sectors which must have been erased and
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	156 rewritten. A read-only implementation can ignore these bytes, as mine does.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	157
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	158 The byte shown as zz is more important though, even to a read-only
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	159 implementation. The 3 values I've encountered in this byte so far are AB, BD
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	160 and BF. Per my current understanding, in a "healthy" FFS exactly one sector
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	161 will have AB in its header, exactly one will have BF, and the rest will have
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	162 BD. The meanings are (or appear to be):
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	163
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	164 AB: the sector holds a vital data structure which I have called the active
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	165 index block;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	166 BD: the sector holds regular data;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	167 BF: the sector is blank except for the header, can be turned into a new AB or
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	168 BD.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	169
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	170 (Note that a flash program operation, which can turn 1s into 0s but not the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	171 other way around, can turn BF into either AB or BD - but neither AB nor BD can
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	172 be turned into any other valid value.)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	173
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	174 In a "virgin" FFS image (as explained above) the first FFS sector is AB, the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	175 last one is BF, and the ones in between are BDs.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	176
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	177 An FFS read operation (a search for a given pathname, or a listing of all
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	178 present directories and files) needs to start with locating the active index
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	179 block - the FFS sector with AB in the header. Following this header, which is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	180 treated as being 16 bytes long (almost everything in Mokopir-FFS is aligned on
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	181 16-byte boundaries), the active index block contains a linear array of 16-byte
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	182 records, each record describing an FFS object: directory, file or file
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	183 continuation chunk.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	184
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	185 Here is my current understanding of the 16-byte index block record structure:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	186
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	187 2 bytes: Length of the described chunk in bytes
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	188 1 byte: Purpose/meaning not understood, ignored by my current code
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	189 1 byte: Object type
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	190 2 bytes: Descendant pointer
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	191 2 bytes: Sibling pointer
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	192 4 bytes: Data pointer
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	193 4 bytes: Purpose/meaning not understood, ignored by my current code
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	194
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	195 (On the Calypso phones of interest, all multibyte fields are in the native
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	196 little-endian byte order of the ARM7TDMI processor.)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	197
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	198 The active index block gets filled with these records as objects are created;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	199 the first record goes right after the 'Ffs#'...AB header (padded to 16 bytes);
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	200 the last record (at any given moment) is followed by blank flash for the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	201 remainder of the sector. Records thus appear in the order in which they are
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	202 created, which bears no direct relation to the directory tree structure.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	203
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	204 The objects, each described by a record in the index block, are organized into
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	205 a tree structure by the descendant and sibling pointers, plus the object type
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	206 indicator byte. Let's start with the latter; the following objtype byte values
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	207 have been observed:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	208
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	209 00: deleted object - a read-only implementation should ignore everything except
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	210 the descendant and sibling pointers. (A write-capable implementation would
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	211 need more care - it would need a way of reclaiming dirty flash space taken
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	212 up by deleted/overwritten files.)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	213
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	214 E1: a special file - see the description of the /.journal file further down
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	215 F1: a regular file (head chunk thereof)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	216 F2: a directory
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	217 F4: file continuation chunk (explained below)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	218
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	219 Each record in the index block has an associated chunk in one of the data
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	220 sectors; the index record contains fields giving the address and length of this
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	221 chunk. The length of a chunk is always a nonzero multiple of 16 bytes, and is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	222 stored (as a number in bytes) in the first 16-bit field of the 16-byte index
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	223 entry. The address of each chunk is given by the data pointer field of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	224 index record, and it is reckoned in 16-byte units (thereby 16-byte alignment is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	225 required) from the beginning of the FFS sector group in the flash address space.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	226
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	227 For objects of type F1 and F2 (regular files and directories) the just-described
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	228 chunk begins with the name of the file or subdirectory as a NUL-terminated ASCII
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	229 string. This name is just for the current level of the directory tree, just
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	230 like in UNIX directories, thus one will have chunk names like gsm, l3, eplmn
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	231 etc, rather than /gsm/l3/eplmn. One practical effect is that one can't readily
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	232 see pathnames or any of the directory structure by looking at an FFS image as a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	233 raw hex dump; the structure is only revealed when one uses a parsing program
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	234 like those which accompany this document.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	235
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	236 In the case of directories, the "chunk" part of the object contains only the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	237 name of the directory itself, padded with FFs to a 16-byte boundary. For
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	238 example, an FFS directory named /gsm would be represented by an object
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	239 consisting of two flash writes: a 16-byte entry in the active index block, with
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	240 the object type byte set to F2, and a corresponding 16-byte chunk in one of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	241 data sectors, with the 16 bytes containing "gsm", a terminating NUL byte, and
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	242 12 FF bytes to pad up to 16. In the case of files, this name may be followed
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	243 by the first chunk of file data content, as explained further down.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	244
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	245 In order to parse the FFS directory tree (whether the objective is to dump the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	246 whole thing recursively or to find a specific file given a pathname), one needs
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	247 to first (well, after finding the active AB block) find the root directory node.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	248 The root directory object is similar to other directory objects: it has a type
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	249 of F2, and an associated chunk of 16 bytes in one of the data sectors. The
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	250 latter contains the name of the root node: on the Pirelli it is "/", whereas on
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	251 my GTA02 it is "/ffs-root".
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	252
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	253 The astute reader should notice that it really makes no sense to store a name
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	254 for the root node, and indeed, this name plays no part in the traversal of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	255 directory tree given an absolute pathname. But instead this name, or rather
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	256 its first character, appears to be used for the purpose of locating the root
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	257 node itself. At first I had assumed that the index record for the root node is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	258 always the first record in the active index block right after the signature
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	259 header - that is how it is in "virgin" FFS images, and also in some quite non-
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	260 virgin ones I have pulled from my daily-use Pirelli. Naturally my first version
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	261 of the Mokopir-FFS (then called MysteryFFS) extraction utility expected the root
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	262 node to always be at index #1. But then I got some additional Pirelli phones,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	263 and discovered that in certain cases, index record #1 is a deleted object (the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	264 original root node which has been deleted), and the new active root node is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	265 somewhere in the middle of the index!
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	266
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	267 Thus it appears that in order to find the active root node, one needs to scan
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	268 the active index block linearly from the beginning (disregarding the tree
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	269 structure pointers in this initial pass), looking for a non-deleted object of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	270 type F2 (a directory) whose corresponding name chunk sports a name beginning
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	271 with the '/' character. (Anyone who's been raised in UNIX will immediately
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	272 know that the path separator character '/' is the only character other than NUL
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	273 that's absolutely forbidden in the individual filenames - so this special
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	274 "root node name" is the only case of a '/' character appearing in what would
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	275 otherwise be a regular filename.)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	276
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	277 [What causes the root node to be somewhere other than at index #1? I assume it
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	278 has to do with the dirty space reclamation / data movement algorithm. In a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	279 "virgin" FFS image the very first sector is the active index block, and the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	280 following sector is the first to hold chunks, beginning with the name chunk of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	281 the root node. Now what happens if all data in that sector aside from the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	282 root node name and some other mostly-static directory names becomes dirty,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	283 i.e., belonging to deleted or overwritten files? How would that flash space
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	284 get reclaimed? I assume that the FFS firmware algorithm moves all still-active
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	285 chunks to a new flash sector, invalidating the old copies - turning the latter
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	286 into deleted objects. The root node will be among them. Then at some point
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	287 the active index block is going to fill up too, and will need to be rewritten
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	288 into a new sector - at which point the previously-deleted index entries are
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	289 omitted and the root node becomes #1 again...]
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	290
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	291 Tree structure
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	292
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	293 Once the root node has been found, the descendant and sibling pointers are used
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	294 to traverse the tree structure. For each directory object, including the root
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	295 node, the descendant pointer points to the first child object of this directory:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	296 the first file or subdirectory contained therein. (Descendant and sibling
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	297 pointers take the form of index numbers in the active index block. A "nil"
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	298 pointer is indicated by all 1s (FFFF) - the usual all-0s NULL pointer convention
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	299 couldn't be used because it's flash, where the blank state is all 1s.) If the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	300 descendant pointer of a directory object is nil, that means an empty directory.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	301 The sibling pointer of each file or directory points to its next sibling, i.e.,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	302 the next member of the same parent directory. The sibling pointer of the root
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	303 node is nil.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	304
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	305 Data content of files
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	306
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	307 Objects of type F1 are the head chunks of files. Each file has a head chunk,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	308 and may or may not have continuation chunks. More precisely, the head chunk
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	309 may contain only the name (or viewed alternatively, 0 bytes of data), or it may
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	310 contain a nonzero number of payload bytes; orthogonally to this variability,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	311 there may or may not be continuation chunk(s) present.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	312
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	313 Continuation chunks
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	314
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	315 The descendant pointer of each file head object (the object of type F1, the one
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	316 reached by traversing the directory tree) indicates whether or not there are
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	317 any continuation chunks present. If this descendant pointer is nil, there are
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	318 no continuation chunks; otherwise it points to the first continuation chunk
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	319 object. File continuation objects have type F4, don't have any siblings (the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	320 sibling pointer is nil - but see below regarding relocated chunks), and the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	321 descendant pointer of each continuation object points to the next continuation
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	322 object, if there is one - nil otherwise.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	323
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	324 Payload data delineation
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	325
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	326 Each chunk, whether head or continuation, always has a length that is a nonzero
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	327 multiple of 16 bytes. The length of the chunk here means the amount of flash
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	328 space it occupies in its data sector - which is NOT equal to the payload data
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	329 length.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	330
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	331 The head chunk of each file begins with the filename, terminated by a NUL byte.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	332 If there are any payload data bytes present in this head chunk (I'll explain
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	333 momentarily how you would tell), the byte immediately after the NUL that
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	334 terminates the filename is the first byte of the payload. In the case of a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	335 continuation chunk, there is no filename and the first byte of the chunk is the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	336 first byte of that chunk's portion of the user data payload.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	337
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	338 Each data-containing chunk (head or continuation) has the following termination
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	339 after the last byte of that chunk's payload data: one byte of 00, followed by
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	340 however many bytes are needed ([0,15] range) of FFs to pad to a 16-byte
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	341 boundary. A file head chunk that has no payload data has the same format as a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	342 directory name chunk: filename followed by its terminating NUL followed by
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	343 [0,15] bytes of FFs to pad to the next 16-byte boundary.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	344
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	345 When working with a head chunk, find the beginning of possible payload data (1
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	346 byte after the filename terminating NUL) and find the end per the standard
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	347 termination logic: scanning from the end of the chunk, skip FFs until 00 is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	348 found (encountering anything else is an error). If the head chunk has no data,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	349 the effective data length (end_pointer - start_pointer) will be 0 or -1. (The
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	350 latter possibility is the most likely, as there will normally be a "shared" 00
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	351 byte, serving as both the filename terminator and the 00 before the padding
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	352 FF bytes.)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	353
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	354 Relocated chunks
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	355
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	356 Let's go back to the scenario in which a particular data sector is full (no more
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	357 usable free space left) and contains a mixture of active and dirty (deleted or
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	358 invalidated) data. How does the dirty flash space get reclaimed, so that the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	359 amount of available space (blank flash ready to hold new data) becomes equal to
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	360 the total FFS size minus the total size of active files and overhead? It can
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	361 only be done by relocating the still-active objects from the full sector to a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	362 new one, invalidating the old copies, and once the old sector consists of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	363 nothing but invalidated data, subjecting it to flash erasure.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	364
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	365 So how do the active FFS objects get relocated from a "condemned" sector to a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	366 new one? If the object is a directory, a new index entry is created, pointing
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	367 to the newly relocated name chunk, but it is then made to fit into the old tree
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	368 structure without disrupting the latter: the new index entry is added at the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	369 tail of the sibling-chain of the parent directory's descendants, the old index
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	370 entry for the same directory is invalidated (as if the directory were rmdir'ed),
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	371 and the descendant pointer of the newly written index entry is set to a copy of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	372 the descendant pointer from the old index entry for the same directory. The
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	373 same approach is used when the head chunk of a file needs to be relocated; in
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	374 both cases a read-only FFS implementation doesn't need to do anything special to
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	375 support reading file and directory objects that have been relocated in this
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	376 manner.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	377
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	378 However, if the relocated object is a file continuation chunk, then the manner
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	379 in which such objects get relocated does affect file reading code. What if a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	380 chunk in the middle of a chain linked by "descend" pointers needs to be moved?
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	381 What happens in this case is that the old copy of the chunk gets invalidated
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	382 (the object type byte turned to 00) like in the other object relocating cases,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	383 and the sibling pointer of that old index entry (which was originally FFFF as
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	384 continuation objects have no siblings) is set to point to the new index entry
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	385 for the same chunk. The "descend" pointer in the new index entry is a copy of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	386 that pointer from the old index entry.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	387
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	388 The manner of chunk relocation just described has been observed in the FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	389 images read out of my most recent batch of Pirelli phones - the same ones in
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	390 which the root directory object is not at index #1. Thinking about it as I
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	391 write this, I've realized that the way in which continuation objects get
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	392 relocated is exactly the same as for other object types - thus the compaction
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	393 code in the firmware doesn't need to examine what object type it is moving.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	394 However, the case of continuation chunk relocation deserves special attention
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	395 because it affects a read-only implementation like ours - the utilities whose
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	396 source accompanies this document used to fail on these FFS images until I
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	397 implemented the following additional handling:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	398
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	399 When following the chunk chain of a file, normally the only object type that's
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	400 expected is F4 - any other object type is an error. However, as a result of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	401 chunk relocation, one can also encounter deleted objects, i.e., type == 00.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	402 If such a deleted object is encountered, follow its sibling pointer, which must
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	403 be non-nil.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	404
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	405 Journal file
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	406
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	407 Every Mokopir-FFS image I've seen so far contains a special file named
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	408 /.journal; this file is special in the following ways:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	409
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	410 * The object type byte is E1 instead of F1;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	411 * Unlike regular files, this special file is internally-writable.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	412
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	413 What I mean by the above is that regular files are mostly immutable: once a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	414 file has been created with some data content in the head chunk, it can only be
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	415 either appended to (one or more continuation chunks added), or overwritten by
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	416 creating a new file with the same name at the same level in the tree hierarchy
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	417 and invalidating the old one. But the special /.journal file is different: I
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	418 have never observed it to consist of more than the head chunk, and this head
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	419 chunk is pre-allocated with some largish and apparently fixed length (4 KiB on
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	420 my GTA02, 16 KiB on the Pirelli). This pre-allocated chunk contains what look
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	421 like 16-byte records at the beginning (on the first 4-byte boundary after the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	422 NUL terminating the ".journal" name), followed by blank flash for the remainder
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	423 of the pre-allocated chunk - so it surely looks like new flash writes happen
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	424 within this chunk.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	425
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	426 I do not currently know the purpose of this /.journal file or the meaning of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	427 records it seems to contain. This understanding would surely be needed if one
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	428 wanted to create FFS images from scratch or to implement FFS write operations,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	429 but I reason that a read-only implementation can get away with simply ignoring
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	430 this file. I reason that this file can't be necessary in order to parse an FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	431 image for reading because one needs to parse the tree structure first in order
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	432 to locate this journal file itself.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	433
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	434 -------------------------------------------------------------------------------
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	435
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	436 That's all I can think of right now. If anything is unclear, see the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	437 accompanying source code for the listing/extraction utilities: with the general
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	438 explanation given by this document, it should be clear what my code does and
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	439 why. And if a given piece of knowledge is found neither in this document nor
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	440 in my source code, then I don't know it myself either, and my read-only
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	441 Mokopir-FFS implementation makes do without it.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	442
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	443 All knowledge contained herein has been recovered by reverse engineering.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	444 Believe it or not, I have figured it out by staring at the hex dump of FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	445 sectors, reasoning about how one could possibly implement an FFS given the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	446 requirement of dynamic writability and the physical constraints of flash memory,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	447 and writing listing/extraction test code iteratively until I got something that
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	448 appears to correctly parse all FFS images available to me - the result is the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	449 code in this package.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	450
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	451 I never got as far as attempting to locate the FFS implementation routines
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	452 within the proprietary firmware binary code images, and I haven't found an
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	453 implementation of this particular FFS in any of the leaked sources yet either.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	454 The TSM30 code doesn't seem to be of any use as its FFS appears to be totally
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	455 different. As to the more recently found LoCosto code leak, I found that one a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	456 few days after I got the Moko/Pirelli "MysteryFFS" reverse-engineered on my
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	457 own, and when I did look at the FFS in the LoCosto code later, I saw what seems
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	458 to be a different FFS as well.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	459
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	460 Michael Spacefalcon
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7 Mychaela Falconia <falcon@freecalypso.org> parents: diff changeset	461 SE 52 Mes 16

FreeCalypso > hg > freecalypso-tools

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