These interfaces are broken for about 9 months, maybe longer than that.
At this point, this is just a dead code nobody tests or tries to use, so
let's remove it instead of keeping a stale code just for the sake of
keeping it and hoping someone will fix it.
To better justify this, I read that OpenBSD removed loadable kernel
modules in 5.7 release (2014), mainly for the same reason we do -
nobody used it so they had no good reason to maintain it.
Still, OpenBSD had LKMs being effectively working, which is not the
current state in our project for a long time.
An arguably better approach to minimize the Kernel image size is to
allow dropping drivers and features while compiling a new image.
We are not using this for anything and it's just been sitting there
gathering dust for well over a year, so let's stop carrying all this
complexity around for no good reason.
This syscall allows userspace to register a keyed string that appears in
a new "strings" JSON object in profile output.
This will be used to add custom strings to profile signposts. :^)
This patch adds a vDSO-like mechanism for exposing the current time as
an array of per-clock-source timestamps.
LibC's clock_gettime() calls sys$map_time_page() to map the kernel's
"time page" into the process address space (at a random address, ofc.)
This is only done on first call, and from then on the timestamps are
fetched from the time page.
This first patch only adds support for CLOCK_REALTIME, but eventually
we should be able to support all clock sources this way and get rid of
sys$clock_gettime() in the kernel entirely. :^)
Accesses are synchronized using two atomic integers that are incremented
at the start and finish of the kernel's time page update cycle.
This syscall only reads from the shared m_space field, but that field
is only over written to by Process::attach_resources, before the
process was initialized (aka, before syscalls can happen), by
Process::finalize which is only called after all the process' threads
have exited (aka, syscalls can not happen anymore), and by
Process::do_exec which calls all other syscall-capable threads before
doing so. Space's find_region_containing already holds its own lock,
and as such there's no need to hold the big lock.
This syscall doesn't touch any intra-process shared resources and only
accesses the time via the atomic TimeManagement::now so there's no need
to hold the big lock.
This syscall doesn't touch any intra-process shared resources and only
accesses the time via the atomic TimeManagement::current_time so there's
no need to hold the big lock.
This syscall doesn't touch any intra-process shared resources and
reads the time via the atomic TimeManagement::current_time, so it
doesn't need to hold any lock.
Before we start disabling acquisition of the big process lock for
specific syscalls, make sure to document and assert that all the
lock is held during all syscalls.
Currently all syscalls run under the Process:m_big_lock, which is an
obvious bottleneck. Long term we would like to remove the big lock and
replace it with the required fine grained locking.
To facilitate this goal we need a way of gradually decomposing the big
lock into the all of the required fine grained locks. This commit
introduces instrumentation to the syscall table, allowing the big lock
requirement to be toggled on/off per syscall.
Eventually when we are finished, no syscall will required the big lock,
and we'll be able to remove all of this instrumentation.
This was an old SerenityOS-specific syscall for donating the remainder
of the calling thread's time-slice to another thread within the same
process.
Now that Threading::Lock uses a pthread_mutex_t internally, we no
longer need this syscall, which allows us to get rid of a surprising
amount of unnecessary scheduler logic. :^)
Unlike accept() the new accept4() system call lets the caller specify
flags for the newly accepted socket file descriptor, such as
SOCK_CLOEXEC and SOCK_NONBLOCK.
The function fstatat can do the same thing as the stat and lstat
functions. However, it can be passed the file descriptor of a directory
which will be used when as the starting point for relative paths. This
is contrary to stat and lstat which use the current working directory as
the starting for relative paths.
This patch modifies InodeWatcher to switch to a one watcher, multiple
watches architecture. The following changes have been made:
- The watch_file syscall is removed, and in its place the
create_iwatcher, iwatcher_add_watch and iwatcher_remove_watch calls
have been added.
- InodeWatcher now holds multiple WatchDescriptions for each file that
is being watched.
- The InodeWatcher file descriptor can be read from to receive events on
all watched files.
Co-authored-by: Gunnar Beutner <gunnar@beutner.name>
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
While profiling all processes the profile buffer lives forever.
Once you have copied the profile to disk, there's no need to keep it
in memory. This syscall surfaces the ability to clear that buffer.
This returns ENOSYS if you are running in the real kernel, and some
other result if you are running in UserspaceEmulator.
There are other ways we could check if we're inside an emulator, but
it seemed easier to just ask. :^)
Make more of the kernel compile in 64-bit mode, and make some things
pointer-size-agnostic (by using FlatPtr.)
There's a lot of work to do here before the kernel will even compile.
This achieves two things:
- Programs can now intentionally perform arbitrary syscalls by calling
syscall(). This allows us to work on things like syscall fuzzing.
- It restricts the ability of userspace to make syscalls to a single
4KB page of code. In order to call the kernel directly, an attacker
must now locate this page and call through it.
This patch adds sys$msyscall() which is loosely based on an OpenBSD
mechanism for preventing syscalls from non-blessed memory regions.
It works similarly to pledge and unveil, you can call it as many
times as you like, and when you're finished, you call it with a null
pointer and it will stop accepting new regions from then on.
If a syscall later happens and doesn't originate from one of the
previously blessed regions, the kernel will simply crash the process.
