genode

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History

Norman Feske 6609aafb05 Replace Quota_exceeded by Insufficient_ram_quota This patch replaces the 'Parent::Quota_exceeded', 'Service::Quota_exceeded', and 'Root::Quota_exceeded' exceptions by the single 'Insufficient_ram_quota' exception type. Furthermore, the 'Parent' interface distinguished now between 'Out_of_ram' (the child's RAM is exhausted) from 'Insufficient_ram_quota' (the child's RAM donation does not suffice to establish the session). This eliminates ambiguities and removes the need to convert exception types along the path of the session creation. Issue #2398		2017-05-31 13:16:05 +02:00
..
component.h	Replace Quota_exceeded by Insufficient_ram_quota	2017-05-31 13:16:05 +02:00
driver.h	Adjust file headers to refer to the AGPLv3	2017-02-28 12:59:29 +01:00
gpt.h	Adjust file headers to refer to the AGPLv3	2017-02-28 12:59:29 +01:00
main.cc	Adjust file headers to refer to the AGPLv3	2017-02-28 12:59:29 +01:00
mbr.h	Adjust file headers to refer to the AGPLv3	2017-02-28 12:59:29 +01:00
partition_table.h	Adjust file headers to refer to the AGPLv3	2017-02-28 12:59:29 +01:00
README	Make label prefixing more strict	2016-11-30 13:37:07 +01:00
target.mk	Move repositories to 'repos/' subdirectory	2014-05-14 16:08:00 +02:00

README

This directory contains an implementation of a block-device-partition server.

Behavior
--------

The server uses Genode's block-session interfaces as both front and back end,
leading to the most common use case where this server will reside "between" a
block-driver server and a higher level component like a file-system server.

At startup, the partition server will try to parse the master boot record (MBR)
of its back-end block session. If no partition table is found, the whole block
device is exported as partition '0'. In the other case, the MBR and possible
extended boot records (EBRs) are parsed and offered as separate block sessions
to the front-end clients. The four primary partitions will receive partition
numbers '1' to '4' whereas the first logical partition will be assigned to '5'.

The partition server also understands the GUID partition table (GPT). If the
config attribute 'use_gpt' is set to 'yes' it will first try to parse any
existing GPT. In case there is no GPT it will fall back to parsing the MBR.

In order to route a client to the right partition, the server parses its
configuration section looking for 'policy' tags.

XML Syntax:
! <policy labal="<program name>" parition="<partition number>" />

Usage
-----

Configuration snippet with two clients and an (hypothetical) IDE driver:
!<start name="ata_driver">
!  <resource name="RAM" quantum="1M" />
!  <provides><service name="Block"/></provides>
!  <config ata="yes" />
!</start>
!
!<start name="part_blk">
!  <resource name="RAM" quantum="10M" />
!  <provides><service name="Block" /></provides>
!
!  <!-- route part_blk to the ata_driver -->
!  <route>
!    <any-service><child name="ata_driver"/> <parent/><any-child/></any-service>
!  </route>
!
!  <!-- allow program 'test-part1' to access logical partition '6', while program
!      'test-part2' receives access to primary partition 1 -->
!  <config>
!    <policy label_prefix="test-part1" partition="6"/>
!    <policy label_prefix="test-part2" partition="1"/>
!  </config>
!</start>
!
!<!-- part_blk clients -->
!<start name="test-part1">
!  <binary name="test-part"/>
!  <resource name="RAM" quantum="10M" />
!  <route>
!    <any-service> <child name="part_blk" /> <parent/> <any-child/> </any-service>
!  </route>
!</start>
!
!<start name="test-part2">
!  <binary name="test-part"/>
!  <resource name="RAM" quantum="10M" />
!  <route>
!    <any-service> <child name="part_blk" /> <parent/> <any-child/> </any-service>
!  </route>
!</start>