This patch merges the profiling functionality in the kernel with the
performance events mechanism. A profiler sample is now just another
perf event, rather than a dedicated thing.
Since perf events were already per-process, this now makes profiling
per-process as well.
Processes with perf events would already write out a perfcore.PID file
to the current directory on death, but since we may want to profile
a process and then let it continue running, recorded perf events can
now be accessed at any time via /proc/PID/perf_events.
This patch also adds information about process memory regions to the
perfcore JSON format. This removes the need to supply a core dump to
the Profiler app for symbolication, and so the "profiler coredump"
mechanism is removed entirely.
There's still a hard limit of 4MB worth of perf events per process,
so this is by no means a perfect final design, but it's a nice step
forward for both simplicity and stability.
Fixes#4848Fixes#4849
SystemServer now creates the /tmp/coredump and /tmp/profiler_coredumps
directories at startup, ensuring that they are owned by root, and with
basic 0755 permissions.
The kernel will also now refuse to put core dumps in a directory that
doesn't fulfill the following criteria:
- Owned by 0:0
- Directory with sticky bit not set
- 0755 permissions
Fixes#4435Fixes#4850
This doesn't solve half of the problems with /tmp/rpc, but this way we
can at least make it sticky instead of having it fully world-writable
and owned by whoever was the first to bind an RPC socket.
These changes are arbitrarily divided into multiple commits to make it
easier to find potentially introduced bugs with git bisect.Everything:
The modifications in this commit were automatically made using the
following command:
find . -name '*.cpp' -exec sed -i -E 's/dbg\(\) << ("[^"{]*");/dbgln\(\1\);/' {} \;
The DevFS along with DevPtsFS give a complete solution for populating
device nodes in /dev. The main purpose of DevFS is to eliminate the
need of device nodes generation when building the system.
Later on, DevFS will assist with exposing disk partition nodes.
We need to call waitpid until no more waitable children are available.
This is necessary because SIGCHLD signals may coalesce into one when
multiple children terminate almost simultaneously.
This fixes random zombie processes sticking around after e.g. closing
Browser.
Also, switch to EventLoop's asynchronous signal handling mechanism,
which allows more complex operations in the signal handler.
For this kind of services, there's no single PID of a running instance;
there may be multiple, or no instances of the service running at any time.
No keepalive functionality is available in this mode, since "alive" doesn't
make sense for multi-instance services.
At the moment, there's no way to actually create multiple instances of
a service; this is going to be added in the next commit.
* In some cases, we can first call sigaction()/signal(), then *not* pledge
sigaction.
* In other cases, we pledge sigaction at first, call sigaction()/signal()
second, then pledge again, this time without sigaction.
* In yet other cases, we keep the sigaction pledge. I suppose these could all be
migrated to drop it or not pledge it at all, if somebody is interested in
doing that.
It didn't feel right to have a "DHCPClient" in a "Servers" directory.
Rename this to Services to better reflect the type of programs we'll
be putting in there.
2020-05-08 21:57:44 +02:00
Renamed from Servers/SystemServer/main.cpp (Browse further)
