This patch adds support for the wait4 system call, and with that the
wait3 call as well. The implementation is absolutely minimal: only
user and system times of the exited child are returned (with all other
rusage fields left zero), and there is no support for tracers. Still,
this should cover the main use cases of wait4.
Change-Id: I7a04589a8423a23990ab39aa38e85d535556743a
- the userland call is now made to PM only, and PM relays the call to
other servers as appropriate; this is an ABI change that will
ultimately allow us to add proper support for wait3() and the like;
for the moment there is backward compatibility;
- the getrusage-specific kernel subcall has been removed, as it
provided only redundant functionality, and did not provide the means
to be extended correctly in the future - namely, allowing the kernel
to return different values depending on whether resource usage of
the caller (self) or its children was requested;
- VM is now told whether resource usage of the caller (self) or its
children is requested, and it refrains from filling in wrong values
for information it does not have;
- VM now uses the correct unit for the ru_maxrss values;
- VFS is cut out of the loop entirely, since it does not provide any
values at the moment; a comment explains how it should be readded.
Change-Id: I27b0f488437dec3d8e784721c67b03f2f853120f
The current values were both inaccurate (especially for dynamically
linked executables) and using the wrong unit (bytes, instead of
kilobytes times ticks-of-execution). For now we are better off not
populating these fields at all.
Change-Id: I195a8fa8db909e64a833eec25f59c9ee0b89bdc5
POSIX states that times() and getrusage() should only return child
user and system times of terminated children for which wait*() has
returned their PIDs.
Change-Id: I38e19ad71543a3b91e944bef8e4e1bd903de51bf
Currently, the userland ABI uses a single field ('user_sp') far
into the very large 'kinfo' structure on the shared kernel
information page. This precludes us from modifying or getting
rid of 'kinfo' in the future without breaking userland. This
patch adds a separate 'kuserinfo' structure to the kernel
information page, with only information that is part of the
userland ABI, in an extensible manner. Userland now uses this
field if it is present, and falls back to the old field if not.
Change-Id: Ib7b24b53a440f40a2edc28cdfa48447ac2179288
Please note that this information is for use by system services only!
The clock facility is not ready to be used directly by userland, and
thus, this kernel page extension is NOT part of the userland ABI.
For service programmers' convenience, change the prototype of the
getticks(3) to return the uptime clock value directly, since the call
can no longer fail.
Correct the sys_times(2) reply message to use the right field type
for the boot time.
Restructure the kernel internals a bit so as to have all the clock
stuff closer together.
Change-Id: Ifc050b7bd253aecbe46e3bd7d7cc75bd86e45555
Instead of importing an external _minix_kerninfo variable, any code
using the shared kernel page should now call get_minix_kerninfo(3).
Since this is the only logical name for such a function, rename the
previous get_minix_kerninfo call to ipc_minix_kerninfo.
Change-Id: I2e424b6fb55aa55d3da850187f1f7a0b7cbbf910
This commits adds a basic infrastructure to support Address Space
Randomization (ASR). In a nutshell, using the already imported ASR
LLVM pass, multiple versions can be generated for the same system
service, each with a randomized, different address space layout.
Combined with the magic instrumentation for state transfer, a system
service can be live updated into another ASR-randomized version at
runtime, thus providing live rerandomization.
Since MINIX3 is not yet capable of running LLVM linker passes, the
ASR-randomized service binaries have to be pregenerated during
crosscompilation. These pregenerated binaries can then be cycled
through at runtime. This patch provides the basic proof-of-concept
infrastructure for both these parts.
In order to support pregeneration, the clientctl host script has
been extended with a "buildasr" command. It is to be used after
building the entire system with bitcode and magic support, and will
produce a given number of ASR-randomized versions of all system
services. These services are placed in /usr/service/asr in the
image that is generated as final step by the "buildasr" command.
In order to support runtime updating, a new update_asr(8) command
has been added to MINIX3. This command attempts to live-update the
running system services into their next ASR-randomized versions.
For now, this command is not run automatically, and thus must be
invoked manually.
Technical notes:
- For various reasons, magic instrumentation is x86-only for now,
and ASR functionality is therefore to be used on x86 only as well.
- The ASR-randomized binaries are placed in numbered subdirectories
so as not to have to change their actual program names, which are
assumed to be static in various places (system.conf, procfs).
- The root partition is typically too small to contain all the
produced binaries, which is why we introduce /usr/service. There
is a symlink from /service/asr to /usr/service/asr for no other
reason than to let userland continue to assume that all services
are reachable through /service.
- The ASR count field (r_asr_count/ASRcount) maintained by RS is not
used within RS in any way; it is only passed through procfs to
userland in order to allow update_asr(8) to keep track of which
version is currently loaded without having to maintain own state.
- Ideally, pre-instrumentation linking of a service would remove all
its randomized versions. Currently, the user is assumed not to
perform ASR instrumentation and then recompile system services
without performing ASR instrumentation again, as the randomized
binaries included in the image would then be stale. This aspect
has to be improved later.
- Various other issues are flagged in the comments of the various
parts of this patch.
Change-Id: I093ad57f31c18305591f64b2d491272288aa0937
Lack of alignment causes minix_stack_fill to produce an incorrect
frame layout, subsequently resulting in a crash of the started
process. For now, we assume that the other callers of
minix_stack_fill do get an aligned buffer through sbrk(3), but this
may have to be changed later as well.
Change-Id: I1575bd62b050749d1a1aae7417310c91713462c3
The libexec ELF parser expects to be given a word-aligned buffer,
but the ASR pass may cause VM and VFS to pass it an arbitrarily
aligned buffer, causing libexec to refuse loading the executable.
This patch aligns the buffers explicitly.
Change-Id: Ic2d5fd3a8f204c3e4f000cffdb7ac71c8339257a
- do not allow live update for request and protocol free states if
there are any worker threads that have pending or active work;
- destroy all worker threads before such live updates and recreate
them afterwards, because transferring (the contents of) the
thread stacks is not an option at this time;
- recreate worker threads in the new instance only if they were
shut down before the state transfer, by letting RS provide the
original preparation state as initialization information.
Change-Id: I846225f5b7281f19e69175485f2c88a4b4891dc2
The bitcode file given to the instrumentation pass does not include
certain weak symbols, in particular regcomp and regfree, which are
required to be visible to the magic pass for state transfer to work
correctly. This patch forces DS to make the calls using their actual
symbol names (with leading underscore), thus resolving the issue, but
this issue should really be solved in a cleaner and more generic way.
Change-Id: Iebee4341cc30ddabcf7593afb5c49d41c0839863
That way, these pages are transferred during live update, as they
should. This resolves a mfs crash after a number of live updates.
Change-Id: Ia53bec2692b2114c29b96a453beb0f915f56453a
This patch changes the VM makefile to specify that the magic pass is
to skip memory function instrumentation, and to transfer the data
variables of the malloc code (thus overriding the exception we made
for all other system services). We add two magic pass flags to
achieve this. Since the magic pass is a big bowl of spaghetti code,
ignoring whitespace changes while viewing this patch is recommended.
Change-Id: I5ab83b23d8437b37c44dea99537bc202469c9df6
Due to changed VM internals, more elaborate preparation is required
before a live update with multiple components including VM can take
place. This patch adds the essential preparation infrastructure to
VM and adapts RS to make use of it. As a side effect, it is no
longer necessary to supply RS as the last component (if at all)
during the set-up of a multicomponent live update operation.
Change-Id: If069fd3f93f96f9d5433998e4615f861465ef448
During live update, the new instance of VM may make changes that,
after a rollback, have to be undone by the old instance of VM, in
particular because both instances share (read-write) all dynamically
allocated pages.
Change-Id: I2bcfa8e627ca6084b1991e0af7cccecc683894a2
A missing check to see whether the range being transferred is sane
(with a starting address lower than an ending address) caused extra
memory to be marked erroneously as copy-on-write for some processes,
ultimately resulting in pagefaults on the stack during live update
rollback.
Change-Id: I1516b509b485379606d8df05b8a0f514896a0f19
If the stack is not mapped at the VM_DATATOP (e.g. booted with
ac_layout = 1), there might be some more regions hiding above
the stack. We also have to transfer those.
Change-Id: Idf3b94a36fcec8a10ace2f6dffe816faf0a88f60
. make sure the priv id etc is maintained so
future privctl talk about the right thing
. solves broken IPC after update
Change-Id: I17ed0212c22d634e6db1e80f8dcb2fb8bffe82c6
The 'memory' service has holes in its data section, which causes
problems during state transfer. Since VM cannot handle page faults
during a multicomponent-with-VM live update, the state transfer must
ensure that no page faults occur during copying. Therefore, we now
query VM about the regions to copy, thus skipping holes. While the
solution is not ideal, it is sufficiently generic that it can be used
for the data section state transfer of all processes, and possibly
for state transfer of other regions in the future as well.
Change-Id: I2a71383a18643ebd36956c396fbd22c8fd137202
Two bugs fixed wrt vm restartability.
. make sure pagetable data is only allocated
using dynamic data instead of static spare pages
(bootstrap pages). They are needed for bootstrap
but now repeat some of the initialization so only
dynamic data remains. This solves the problem of
physical addresses changing (as static pages are
re-allocated for the new instance) after update.
. pt_ptalloc has to be specified in bytes instead of
pde slot numbers. leaving pt_pt NULL causes mapping
transfers to fail because NULL happens to be mapped in
then and updates then happen there.
. added some sanity checks against the above happening.
The new state is that VM can update many times, but the system
isn't fully reliable afterwards yet.
Change-Id: I7313602c740cdae8590589132291116ed921aed7
Allow extra space for in-band metadata when allocating cache blocks.
Edited by David van Moolenbroek: since this effectively halves the
potential size of the typical file system cache, do this only when
compiling with instrumentation.
Change-Id: I0840af6420899ede2d5bb7539e79c0a456b5128d
VM used to call sendrec to send a boot-time RS_INIT reply to RS, but
RS could run into a pagefault at the same time, thus spawning a
message to VM, resulting in a deadlock. We resolve this situation by
making VM acknowledge RS_INIT asynchronously at boot time, while
retaining the synchronous sendrec for subsequent RS_INIT responses.
Change-Id: I3cb72d7f8d6b9bfdc59a85958ada739c37fa3bde
The following services have been updated to support stateful restarts:
- Drivers: tty
- Filesystems: isofs, mfs, pfs, libvtreefs-based file servers
- System servers: tty, ds, pm, vfs, vm
Change-Id: Ie84baa3ba1774047b3ae519808fe4116928edabb
Previously, RS would clean up dead services only when it is idle.
During shutdown, all services are marked with the 'exiting' flag,
and these flags lead RS to conclude it is not idle. Therefore, at
shutdown time, no services were cleaned up anymore, leading to
deadlock situations. For example, VFS could end up waiting for a
service that was already dead, or one driver could end up waiting
for an interrupt on a line shared with another dead driver.
While it may be possible to ignore RS_EXITING when checking idle
status, other flags may have the same ultimate effect. Therefore,
this patch skips the idle check altogether when in shutdown mode.
Change-Id: I071fa9545da1d43c5e5c2e0bc2b6c173e3bb57c3
While in a multicomponent live update that includes RS, the new RS
instance may receive heartbeat replies which, after a rollback, the
old RS instance will then never see. As a result, the rolled-back
RS instance may end up killing well-behaving services.
Change-Id: I0f0af283c33502d5d55b27e353b62aec2e301285
Add support for compact address layout. This feature can be enabled
through the ac_layout=1 boot option.
Change-Id: Ie20b808fce32b5c54d0a7e7210e0084a540e9613
