Problem:
- C functions with no arguments require a single `void` in the argument list.
Solution:
- Put the `void` in the argument list of functions in C header files.
This new flag controls two things:
- Whether the kernel will generate core dumps for the process
- Whether the EUID:EGID should own the process's files in /proc
Processes are automatically made non-dumpable when their EUID or EGID is
changed, either via syscalls that specifically modify those ID's, or via
sys$execve(), when a set-uid or set-gid program is executed.
A process can change its own dumpable flag at any time by calling the
new sys$prctl(PR_SET_DUMPABLE) syscall.
Fixes#4504.
Make it possible to bail out of ELF::Image::for_each_program_header()
and then do exactly that if something goes wrong during executable
loading in the kernel.
Also make the errors we return slightly more nuanced than just ENOEXEC.
POSIX says we can set errno EINVAL and return -1 if the action is not
supported. This is better than crashing, and fixes bash crashing
whenever you press ^C.
This commit gets rid of ELF::Loader entirely since its very ambiguous
purpose was actually to load executables for the kernel, and that is
now handled by the kernel itself.
This patch includes some drive-by cleanup in LibDebug and CrashDaemon
enabled by the fact that we no longer need to keep the ref-counted
ELF::Loader around.
It was really weird that ELF loading was performed by the ELF::Loader
class instead of just being done by the kernel itself. This patch moves
all the layout logic from ELF::Loader over to sys$execve().
The kernel no longer cares about ELF::Loader and instead only uses an
ELF::Image as an interpreting wrapper around executables.
Now that the CrashDaemon symbolicates crashes in userspace, let's take
this one step further and stop trying to symbolicate userspace programs
in the kernel at all.
Let's just say no to shenanigans by capping images at 16384 pixels both
wide and tall. If a day comes in the future where we need to handle
images larger than this, we can deal with it then.
We now configure the gcc spec files to use a different crt files for
static & PIE binaries.
This relieves us from the need to explicitly specify the desired crt0
file in cmake scripts.
I think this is okay, the main thing to protect against is new versions
of the format that we don't know about yet.
This happens because an .S file compiled into libc.so has version 2
instead of version 4 like everything else.
Fixes#4491.
POSIX allows the default streams (stdin, stdout and stderr) to be
macros, which means that on such systems (musl libc is one) building
Lagom will fail due to the File::std*() names.
Also fix any files that use these identifiers.
...and don't let them leak out of their evaluation contexts.
Also keep the exceptions separate from the actual values.
This greatly reduces the number of assertions hit while entering random
data into a sheet.
LibC stdlib `arc4random()` uses the `getrandom` system call which
uses `KernelRng::get_good_random_bytes`.
This ensures that filenames generated using functions such as
`mkstemp()` are suitably randomised and are no longer predictable.
It was possible to go outside the interlacing row strid/offset arrays.
Just fail the decode if this is about to happen. I've added a FIXME
about rejecting such images earlier, since it's a bit sad to only do
this once we realize the pass index is about to overflow.
Found by oss-fuzz: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28239
Problem:
- Functions are duplicated in [PBM,PGM,PPM]Loader class
implementations. They are functionally equivalent. This does not
follow the DRY (Don't Repeat Yourself) principle.
Solution:
- Factor out the common functions into a separate file.
- Refactor common code to generic functions.
- Change `PPM_DEBUG` macro to be `PORTABLE_IMAGE_LOADER_DEBUG` to work
with all the supported types. This requires adding the image type to
the debug log messages for easier debugging.
This implements a number of changes related to time:
* If a HPET is present, it is now used only as a system timer, unless
the Local APIC timer is used (in which case the HPET timer will not
trigger any interrupts at all).
* If a HPET is present, the current time can now be as accurate as the
chip can be, independently from the system timer. We now query the
HPET main counter for the current time in CPU #0's system timer
interrupt, and use that as a base line. If a high precision time is
queried, that base line is used in combination with quering the HPET
timer directly, which should give a much more accurate time stamp at
the expense of more overhead. For faster time stamps, the more coarse
value based on the last interrupt will be returned. This also means
that any missed interrupts should not cause the time to drift.
* The default system interrupt rate is reduced to about 250 per second.
* Fix calculation of Thread CPU usage by using the amount of ticks they
used rather than the number of times a context switch happened.
* Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it
for most cases where precise timestamps are not needed.
Problem:
- `Streamer` is the same in [PBM,PGM,PPM]Loader class implementations.
Solution:
- Extract it to its own header file to reduce maintenance burden.
- Implement `read` in terms of `read_bytes` to make the class "DRY".
- Decorate all functions with `constexpr`.
