SYSLIB CHANGES:
- SEF framework now supports a new SEF Init request type from RS. 3 different
callbacks are available (init_fresh, init_lu, init_restart) to specify
initialization code when a service starts fresh, starts after a live update,
or restarts.
SYSTEM SERVICE CHANGES:
- Initialization code for system services is now enclosed in a callback SEF will
automatically call at init time. The return code of the callback will
tell RS whether the initialization completed successfully.
- Each init callback can access information passed by RS to initialize. As of
now, each system service has access to the public entries of RS's system process
table to gather all the information required to initialize. This design
eliminates many existing or potential races at boot time and provides a uniform
initialization interface to system services. The same interface will be reused
for the upcoming publish/subscribe model to handle dynamic
registration / deregistration of system services.
VM CHANGES:
- Uniform privilege management for all system services. Every service uses the
same call mask format. For boot services, VM copies the call mask from init
data. For dynamic services, VM still receives the call mask via rs_set_priv
call that will be soon replaced by the upcoming publish/subscribe model.
RS CHANGES:
- The system process table has been reorganized and split into private entries
and public entries. Only the latter ones are exposed to system services.
- VM call masks are now entirely configured in rs/table.c
- RS has now its own slot in the system process table. Only kernel tasks and
user processes not included in the boot image are now left out from the system
process table.
- RS implements the initialization protocol for system services.
- For services in the boot image, RS blocks till initialization is complete and
panics when failure is reported back. Services are initialized in their order of
appearance in the boot image priv table and RS blocks to implements synchronous
initialization for every system service having the flag SF_SYNCH_BOOT set.
- For services started dynamically, the initialization protocol is implemented
as though it were the first ping for the service. In this case, if the
system service fails to report back (or reports failure), RS brings the service
down rather than trying to restart it.
SYSLIB CHANGES:
- SEF must be used by every system process and is thereby part of the system
library.
- The framework provides a receive() interface (sef_receive) for system
processes to automatically catch known system even messages and process them.
- SEF provides a default behavior for each type of system event, but allows
system processes to register callbacks to override the default behavior.
- Custom (local to the process) or predefined (provided by SEF) callback
implementations can be registered to SEF.
- SEF currently includes support for 2 types of system events:
1. SEF Ping. The event occurs every time RS sends a ping to figure out
whether a system process is still alive. The default callback implementation
provided by SEF is to notify RS back to let it know the process is alive
and kicking.
2. SEF Live update. The event occurs every time RS sends a prepare to update
message to let a system process know an update is available and to prepare
for it. The live update support is very basic for now. SEF only deals with
verifying if the prepare state can be supported by the process, dumping the
state for debugging purposes, and providing an event-driven programming
model to the process to react to state changes check-in when ready to update.
- SEF should be extended in the future to integrate support for more types of
system events. Ideally, all the cross-cutting concerns should be integrated into
SEF to avoid duplicating code and ease extensibility. Examples include:
* PM notify messages primarily used at shutdown.
* SYSTEM notify messages primarily used for signals.
* CLOCK notify messages used for system alarms.
* Debug messages. IS could still be in charge of fkey handling but would
forward the debug message to the target process (e.g. PM, if the user
requested debug information about PM). SEF would then catch the message and
do nothing unless the process has registered an appropriate callback to
deal with the event. This simplifies the programming model to print debug
information, avoids duplicating code, and reduces the effort to print
debug information.
SYSTEM PROCESSES CHANGES:
- Every system process registers SEF callbacks it needs to override the default
system behavior and calls sef_startup() right after being started.
- sef_startup() does almost nothing now, but will be extended in the future to
support callbacks of its own to let RS control and synchronize with every
system process at initialization time.
- Every system process calls sef_receive() now rather than receive() directly,
to let SEF handle predefined system events.
RS CHANGES:
- RS supports a basic single-component live update protocol now, as follows:
* When an update command is issued (via "service update *"), RS notifies the
target system process to prepare for a specific update state.
* If the process doesn't respond back in time, the update is aborted.
* When the process responds back, RS kills it and marks it for refreshing.
* The process is then automatically restarted as for a buggy process and can
start running again.
* Live update is currently prototyped as a controlled failure.
KERNEL CHANGES:
- The kernel only knows about privileges of kernel tasks and the root system
process (now RS).
- Kernel tasks and the root system process are the only processes that are made
schedulable by the kernel at startup. All the other processes in the boot image
don't get their privileges set at startup and are inhibited from running by the
RTS_NO_PRIV flag.
- Removed the assumption on the ordering of processes in the boot image table.
System processes can now appear in any order in the boot image table.
- Privilege ids can now be assigned both statically or dynamically. The kernel
assigns static privilege ids to kernel tasks and the root system process. Each
id is directly derived from the process number.
- User processes now all share the static privilege id of the root user
process (now INIT).
- sys_privctl split: we have more calls now to let RS set privileges for system
processes. SYS_PRIV_ALLOW / SYS_PRIV_DISALLOW are only used to flip the
RTS_NO_PRIV flag and allow / disallow a process from running. SYS_PRIV_SET_SYS /
SYS_PRIV_SET_USER are used to set privileges for a system / user process.
- boot image table flags split: PROC_FULLVM is the only flag that has been
moved out of the privilege flags and is still maintained in the boot image
table. All the other privilege flags are out of the kernel now.
RS CHANGES:
- RS is the only user-space process who gets to run right after in-kernel
startup.
- RS uses the boot image table from the kernel and three additional boot image
info table (priv table, sys table, dev table) to complete the initialization
of the system.
- RS checks that the entries in the priv table match the entries in the boot
image table to make sure that every process in the boot image gets schedulable.
- RS only uses static privilege ids to set privileges for system services in
the boot image.
- RS includes basic memory management support to allocate the boot image buffer
dynamically during initialization. The buffer shall contain the executable
image of all the system services we would like to restart after a crash.
- First step towards decoupling between resource provisioning and resource
requirements in RS: RS must know what resources it needs to restart a process
and what resources it has currently available. This is useful to tradeoff
reliability and resource consumption. When required resources are missing, the
process cannot be restarted. In that case, in the future, a system flag will
tell RS what to do. For example, if CORE_PROC is set, RS should trigger a
system-wide panic because the system can no longer function correctly without
a core system process.
PM CHANGES:
- The process tree built at initialization time is changed to have INIT as root
with pid 0, RS child of INIT and all the system services children of RS. This
is required to make RS in control of all the system services.
- PM no longer registers labels for system services in the boot image. This is
now part of RS's initialization process.
- add new "control" config directive, to let drivers restart drivers
(by Jorrit Herder)
- fix bug causing system processes to be started twice sometimes
IS:
- do not use p_getfrom_e for a process that is sending
- register with TTY only function keys that are used
- various header and formatting fixes
- proper shutdown code
TTY:
- restore proper Ctrl+F1 dump contents
isofs:
- don't even try to call sys_exit()
. changed umount() and mount() to call 'service', so that it can include
a custom label, so that umount() works again (RS slot gets freed now).
merged umount() and mount() into one file to encode keep this label
knowledge in one file.
. removed obsolete RS_PID field and RS_RESCUE rescue command
. added label to RS_START struct
. vfs no longer does kill of fs process on unmount (which was failing
due to RS_PID request not working)
. don't assume that if error wasn't one of three errors, that no error
occured in vfs/request.c
mfs changes:
. added checks to copy statements to truncate copies at buffer sizes
(left in debug code for now)
. added checks for null-terminatedness, if less than NAME_MAX was copied
. added checks for copy function success
is changes:
. dump rs label
drivers.conf changes:
. added acl for mfs so that mfs can be started with 'service start',
so that a custom label can be provided
'who', indicating caller number in pm and fs and some other servers, has
been removed in favour of 'who_e' (endpoint) and 'who_p' (proc nr.).
In both PM and FS, isokendpt() convert endpoints to process slot
numbers, returning OK if it was a valid and consistent endpoint number.
okendpt() does the same but panic()s if it doesn't succeed. (In PM,
this is pm_isok..)
pm and fs keep their own records of process endpoints in their proc tables,
which are needed to make kernel calls about those processes.
message field names have changed.
fs drivers are endpoints.
fs now doesn't try to get out of driver deadlock, as the protocol isn't
supposed to let that happen any more. (A warning is printed if ELOCKED
is detected though.)
fproc[].fp_task (indicating which driver the process is suspended on)
became an int.
PM and FS now get endpoint numbers of initial boot processes from the
kernel. These happen to be the same as the old proc numbers, to let
user processes reach them with the old numbers, but FS and PM don't know
that. All new processes after INIT, even after the generation number
wraps around, get endpoint numbers with generation 1 and higher, so
the first instances of the boot processes are the only processes ever
to have endpoint numbers in the old proc number range.
More return code checks of sys_* functions have been added.
IS has become endpoint-aware. Ditched the 'text' and 'data' fields
in the kernel dump (which show locations, not sizes, so aren't terribly
useful) in favour of the endpoint number. Proc number is still visible.
Some other dumps (e.g. dmap, rs) show endpoint numbers now too which got
the formatting changed.
PM reading segments using rw_seg() has changed - it uses other fields
in the message now instead of encoding the segment and process number and
fd in the fd field. For that it uses _read_pm() and _write_pm() which to
_taskcall()s directly in pm/misc.c.
PM now sys_exit()s itself on panic(), instead of sys_abort().
RS also talks in endpoints instead of process numbers.
New Shift-F6 dump for RS server at IS.
New getnpid, getnproc, getpproc library calls at PM.
New reincarnation server (basic functionality is there now).
