MRCI/docs/shared_data.md

6.1 Session/Host Shared Memory

The host use shared shared memory segments to share data with the module processes so the modules can be made aware of various session data points like the currently logged in user id, user name, display name, etc. A shared memory segment is basically a block of memory where multiple processes have access to reading/writing data. The use of shared memory segments is entirely optional so it does not need to be implemented to have a fully functional module.

The session object creates the shared memory segment and assigns a text key unique to just the session. When the session object calls a new module process, it will pass the -mem_ses option with the shared memory key that the module can then use to attach to the segment. The session will also pass the -mem_host option unique to the TCPServer object to get data relevant to the sever object.

As mentioned before, the share memory segments are just blocks of memory. sections 6.2 and 6.3 describes the format of the shared memory and where to find the data based on the memory offset.

Also note, depending on the API used, lock and unlock functions must be used when reading/writing data with the shared memory segments as a way to prevent multiple process from reading/writing the shared data at the same time. Consider reading your API's documentation before attempting to use shared memory segments.

6.2 Session Shared Memory Offsets

Offset	Data	Type	Bytes	Descrition
0	Session ID	Hash	28	a unique hash for the current session.
28	User ID	Hash	32	a unique hash for the currently logged in user account.
60	Client IP	String	78	the ip address of user's client in string form.
138	Client App	String	134	the name of the application the user is currently using.
272	User Name	String	48	current user name.
320	Disp Name	String	64	current display name.
384	Host Rank	uint32	4	current host rank.
388	Active Update	uint8	1	a bool value 0x00 or 0x01 if the session has an active update sub-ch open.
389	Owner Override	uint8	1	also a bool value if the session has the channel owner override flag active.
390	Channel List	uint64 (x200)	1600	a list of up to 200 channel ids that the current user is a member of.
1990	Open Sub-channels	5.3	54	a list of sub-channels the session currently have open.
2044	Writeable Sub-channels	5.3	54	same as the list above except the sub-channels do not have read-only flags.
2098	Pending P2P Request	Hash (x100)	2800	a list of up to 100 session ids that have pending p2p request.
4898	Accepted P2P Request	Hash (x100)	2800	same as above except this list p2p request that was accepted.

notes:

• The "String" data type is TEXT padded with 0x00.
• The list data types are also padded to strings of 0x00 based on the size of each sub-unit.

6.3 Host Shared Memory Offsets

Offset	Data	Type	Bytes	Descrition
0	Number Of Sessions	uint32	4	the number of active concurrent sessions.

6.4 Data Constraints Table

Data	Type	Vaild Size Range	Forbidden Chars	Must Contain
Module Executable Path	String	1-512	|*:"?<>
User Name	String	2-24	spaces or newlines
Email Address	String	4-64	spaces or newlines	@ and .
Password	String	8-200		special chars, numbers, capital letters and common letters.
Command Name	String	1-64	spaces or newlines
Common Name	String	1-136	spaces or newlines
Display Name	String	0-32	newlines
Channel Name	String	4-32	spaces or newlines
Sub-channel Name	String	4-32	spaces or newlines
Client App Name	String	0-67
Command Lib Name	String	0-64
IP Address (string)	String	3-39	spaces or newlines	numbers and . or numbers, A-F and :
User ID	Hash	32-32
Session ID	Hash	28-28
Host Rank	int32	1-4x10^9	non-numeric chars
Max Sessions	int32	1-4x10^9	non-numeric chars
Channel ID	int64	1-18x10^18	non-numeric chars
Command ID	int16	256-65535	non-numeric chars
Async Command ID	int16	1-255	non-numeric chars
Sub-channel ID	int8	0-255	non-numeric chars
Channel Level	int8	1-5	non-numeric chars