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 *
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
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.
Quoting POSIX:
https://pubs.opengroup.org/onlinepubs/009695399/functions/tzset.html
The tzset() function also shall set the external variable daylight
to 0 if Daylight Savings Time conversions should never be applied
for the timezone in use; otherwise, non-zero.
We're already pretending to be in UTC+0 and setting timezone to 0
accordingly, we can also fake the absence of Daylight Savings Time.
Since tzset() itself pretends to succeed (it just sets timezone = 0 for
now), it seems unwise to leave tzname uninitialized. Since Serenity
already assumes UTC pretty much everywhere time is used, let's continue
that trend here. Quoting POSIX:
https://pubs.opengroup.org/onlinepubs/009695399/functions/tzset.html
The tzset() function shall use the value of the environment variable
TZ to set time conversion information used by ctime(), localtime(),
mktime(), and strftime(). If TZ is absent from the environment,
implementation-defined default timezone information shall be used.
So we still don't care about TZ at all, but the program doesn't need to
know! :^)
This matches what musl libc ("UTC") and glibc ("GMT") do, see:
- https://sourceware.org/git/?p=glibc.git;a=blob;f=time/tzset.c
- https://git.musl-libc.org/cgit/musl/tree/src/time/__tz.c
