English fork of the Japanese RaSCSI project. RaSCSI allows a Raspberry Pi to function as emulated SCSI devices (hard disk, CD-ROM, and others) for vintage SCSI-based computers and devices.
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Klaus Kämpf ad5eae93e7
Multiple fixes for ModeSelect (#1405)
* Allow 'empty' ModeSelect6

tl;dr

Treat a computed length of 0 as `has_valid_page_code`.

Details:

The SRM console (aka 'BIOS') of DEC Alpha sends an empty
ModeSelect6 with the following data:
~~~
ModeSelect6, CDB $151000000c00
~~~

That makes 12 byte(s) as follows
~~~
  0  1  2  3   4   5  6  7   8   9 10 11
 00 00 00 08  00  00 00 00  00  00 02 00
~~~

decoding it (accoring to [1], Section 8.3.3, Table 94) gives us

Mode Data Length 0
Medium Type      0
Device-specific  0
Block desc len   8

Density Code     0
Number of blks   0
Reserved         0
Block length     512

`scsi_command_util::ModeSelect` computes
~~~
offset = 4 + buf[3];
~~~

giving 12 and

~~~
length -= offset;
~~~

giving 0.

Thus it never enters the `while` loop and `has_valid_page_code` stays
`false`, raising an error.

[1] [Small Computer System Interface - 2 rev 10L.pdf](https://dn790004.ca.archive.org/0/items/SCSISpecificationDocumentsSCSIDocuments/Small%20Computer%20System%20Interface%20-%202%20rev%2010L.pdf)

Signed-off-by: Klaus Kämpf <kkaempf@gmail.com>

* Allow ModeSelect with page code 1

OpenVMS Alpha (the operating system, not the SRM BIOS) uses
ModeSelect6 with a page code of 1.

The semantics are unknown, just accepting it works for me.

Signed-off-by: Klaus Kämpf <kkaempf@gmail.com>

* Fix page length computation in ModeSelect

tl;dr

The 'skip to next ModeSelect page' computation was off-by-one, either not
taking the page code itself into account or missing the fact that the
page length is given as `n - 1`.

Fix:

Add 1 to the computed length.

Details:

OpenVMS Alpha sends a ModeSelect6 as follows
~~~
command:

ModeSelect6, CDB $151000001900

payload:

 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
00 00 00 08 00 00 00 00 00 00 02 00 01 0a 24 00 00 00 00 00 00 00 00 00 00
~~~

This translates to (accoring to [1], Section 8.3.3)

~~~
Mode Data Length 0
Medium Type      0
Device-specific  0
Block desc len   8
~~~

with the following offset / length computation _before_ the `while` loop
~~~
offset = 12
length = 13
~~~

The first payload section is
~~~
 4  5  6  7  8  9 10 11
00 00 00 00 00 00 02 00
~~~

translating to

~~~
Density Code     0
Number of blks   0
Reserved         0
Block length   0x200 512
~~~

Then follows a pagecode 1 as
~~~
12 13 14 15 16 17 18 19 20 21 22 23 24
01 0a 24 00 00 00 00 00 00 00 00 00 00
~~~

translating to
~~~~
Page code        1
Page length -1  10
Mode parameters 24 00 00 00 00 00 00 00 00 00 00
~~~

computing (inside the `while` loop, as `// Advance to the next page`)

~~~
size =  10 + 2 = 12
~~~

followed by new `offset` and `length` values

~~~
offset = 25
length = 1
~~~

So it stays in the `while` loop (and has a larger-than-buffer `offset`
value)

Signed-off-by: Klaus Kämpf <kkaempf@gmail.com>
2024-01-07 15:06:35 +09:00
.github Remove fullspec/standard sub-folder (#1324) 2023-11-14 15:51:36 +01:00
cpp Multiple fixes for ModeSelect (#1405) 2024-01-07 15:06:35 +09:00
doc Revert "scsictl: Create files with binary/JSON or text format protobuf data (#1369)" 2023-11-27 09:11:43 +09:00
docker Merge pull request #1352 from benjamink/reset-venv-with-env-var 2023-11-17 05:53:20 -05:00
hw Moved hw directory to its own repository (#1011) 2022-12-01 19:20:52 -06:00
ide_setup Add initial IDE setup (#1326) 2023-11-14 15:13:45 +01:00
os_integration Move os_integration to root level (#1085) 2023-01-28 15:03:41 -08:00
python Control Board: Use Pillow 10 API for getting text size 2023-12-18 00:41:51 -08:00
_config.yml Set theme jekyll-theme-midnight 2020-07-04 20:39:04 -05:00
.dockerignore Move os_integration to root level (#1085) 2023-01-28 15:03:41 -08:00
.gitignore Rebrand project to PiSCSI (#1016) 2022-12-05 09:58:23 -08:00
easyinstall.sh Freeze Python requirements for the Control Board client 2023-12-16 01:32:32 -08:00
LICENSE Rebrand project to PiSCSI (#1016) 2022-12-05 09:58:23 -08:00
README.md Add web UI notification for under voltage/throttling events (#1203) 2023-08-31 23:23:12 -07:00

What is PiSCSI?

PiSCSI is a virtual SCSI device emulator that runs on a Raspberry Pi. It runs in userspace, and can emulate several SCSI devices at one time. There is a control interface to attach / detach drives during runtime, as well as insert and eject removable media. This project is aimed at users of vintage Macintosh and Atari computers and more (see compatibility list) from the 1980's and 1990's.

Please check out the full story with much more detail on the wiki!

How do I contribute?

PiSCSI is using the Gitflow Workflow. A quick overview:

  • The main branch should always reflect the contents of the last stable release
  • The develop branch should contain the latest tested & approved updates. Pull requests should be used to merge changes into develop.
  • The rest of the feature branches are for developing new features
  • A tag will be created for each "release". The releases will be named .. where the release number is incremented for each subsequent release tagged in the same calendar month. The first release of the month of January 2021 is called "21.01.01", the second one in the same month "21.01.02" and so on.

Typically, releases will only be planned every few months.

When you are ready to contribute code to PiSCSI, follow the GitHub Forking and Pull Request workflow to create your own fork where you can make changes, and then contribute it back to the project. Please remember to always make Pull Requests against the develop branch.

If you want to add a new translation, or improve upon an existing one, please follow the instructions in the Web Interface README. Once the translation is complete, please use the same workflow as above to contribute it to the project.

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