Currently, LibELF uses the host's page size for validation (even on
Lagom), which causes issues with PrekernelPEImageGenerator, since that
always uses 4 KiB pages for cross-compilation purposes.
The LibELF validate_program_headers method tried to do too many things
at once, and as a result, we had an awkward return type from it.
To be able to simplify it, we no longer allow passing a StringBuilder*
but instead we require to pass an Optional<Elf_Phdr> by reference so
it could be filled with actual ELF program header that corresponds to
an INTERP header if such found.
As a result, we ensure that only certain implementations that actually
care about the ELF interpreter path will actually try to load it on
their own and if they fail, they can have better diagnostics for an
invalid INTERP header.
This change also fixes a bug that on which we failed to execute an ELF
program if the INTERP header is located outside the first 4KiB page of
the ELF file, as the kernel previously didn't have support for looking
beyond that for that header.
Previously, we started parsing the ELF file again in a completely
different place, and without the partial mapping that we do while
validating.
Instead of doing manual parsing in two places, just capture the
requested stack size right after we validated it.
This is needed to avoid including LibC headers in Lagom builds.
Unfortunately, we cannot rely on the build machine to provide a
fully POSIX-compatible ELF header for Lagom builds, so we have to
use our own.
A lot of places were relying on AK/Traits.h to give it strnlen, memcmp,
memcpy and other related declarations.
In the quest to remove inclusion of LibC headers from Kernel files, deal
with all the fallout of this included-everywhere header including less
things.
Some programs explicitly ask for a different initial stack size than
what the OS provides. This is implemented in ELF by having a
PT_GNU_STACK header which has its p_memsz set to the amount that the
program requires. This commit implements this policy by reading the
p_memsz of the header and setting the main thread stack size to that.
ELF::Image::validate_program_headers ensures that the size attribute is
a reasonable value.
This check is here to make sure we only try to load serenity binaries.
However, with -fprofile-instr-generate -fcoverage-mapping, clang
sets the EI_OSABI field to 3, for GNU. The instrumentation uses a lot of
retained COMDAT sections for coverage instrumentation that get the
SHF_GNU_RETAINED section header flag set on them, forcing llvm to set
the ABI to GNU.
GNU ld sometimes generates zero-sized PT_LOAD headers when running with
the "-z separate-code" option. Let's not choke on such headers, we can
just ignore them and move along.
This was causing CrashDaemon to choke on our coredumps. Note that we
didn't care about the validation failures before this change either,
this patch simply reorders the checks to avoid divide-by-zero when
validating an ET_CORE file.
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.
implicitfield