The original loader service was primarily motivated by the
browser-plugin scenario presented on our live CD. The new version
implements a more general session interface, which widens the
application scope of the service and, at the same time, reduces its
implementation complexity.
The complexity reduction is achieved by removing the original limitation
of supplying the new sub system as a single binary blob only. The server
used to implement heuristics and functionality for dealing with
different kinds of blobs such as ELF images or TAR archives. This has
been replaced by a session-local ROM service, which can be equipped with
an arbitrary number of ROM modules supplied by the loader client prior
starting the new sub system. Even though the TAR support has been
removed, a separate instance of the 'tar_rom' service can be used within
the subsystem to provide the formerly built-in functionality.
The new 'chroot' tool at 'os/src/app/chroot' allows for executing
subsystems within chroot jails on Linux. For using the tool, please
refer to the test case 'os/run/chroot.run'. Fixes#37
This patch reads program arguments from the config file and makes them
available to the application via the 'argc' and 'argv' arguments of the
'main()' function. The configuration syntax looks like this:
<config>
<arg value="...">
<arg value="...">
...
</config>
The 'value' attribute of the first <arg> node becomes 'argv[0]' and so on.
Fixes#184.
This patch introduces support for ROM sessions that update their
provided data during the lifetime of the session. The 'Rom_session'
interface had been extended with the new 'release()' and 'sigh()'
functions, which are needed to support the new protocol. All ROM
services have been updated to the new interface.
Furthermore, the patch changes the child policy of init
with regard to the handling of configuration files. The 'Init::Child'
used to always provide the ROM dataspace with the child's config file
via a locally implemented ROM service. However, for dynamic ROM
sessions, we need to establish a session to the real supplier of the ROM
data. This is achieved by using a new 'Child_policy_redirect_rom_file'
policy to handle the 'configfile' rather than handling the 'configfile'
case entirely within 'Child_config'.
To see the new facility in action, the new 'os/run/dynamic_config.run'
script provides a simple scenario. The config file of the test program
is provided by a service, which generates and updates the config data
at regular intervals.
In addition, new support has been added to let slaves use dynamic
reconfiguration. By using the new 'Child_policy_dynamic_rom_file', the
configuration of a slave can be changed dynamically at runtime via the
new 'configure()' function.
The config is provided as plain null-terminated string (instead of a
dataspace capability) because we need to buffer the config data anyway.
So there is no benefit of using a dataspace. For buffering configuration
data, a 'Ram_session' must be supplied. If no 'Ram_session' is specified
at construction time of a 'Slave_policy', no config is supplied to the
slave (which is still a common case).
An example for dynamically reconfiguring a slave is provided by
'os/run/dynamic_config_slave.run'.
