These symlinks' only purpose was to be copied into the rootfs along with
the rest of Base. Instead of storing symlinks to files that either
don't exist in the Base directory, or point to an absolute path outside
of the serenity folder, move these symlinks into the
build-root-filesystem.sh script.
Similar to the FontDatabase, this will be needed for Ladybird to find
emoji images. We now generate just the file name of emoji image in
LibUnicode, and look for that file in the specified path (defaulting to
/res/emoji) at runtime.
`consume_until(foo)` stops before foo, and so does
`ignore_until(Predicate)`, so let's make the other `ignore_until()`
overloads consistent with that so they're less confusing.
This commit moves the implementation of getopt into AK, and converts its
API to understand and use StringView instead of char*.
Everything else is caught in the crossfire of making
Option::accept_value() take a StringView instead of a char const*.
With this, we must now pass a Span<StringView> to ArgsParser::parse(),
applications using LibMain are unaffected, but anything not using that
or taking its own argc/argv has to construct a Vector<StringView> for
this method.
10ms (the default) is ridiculous and causes all kinds of glitches if we
actually want to have a low-latency queue.
<https://gitlab.com/qemu-project/qemu/-/issues/1076#note_996636777>
suggests 2ms (and no lower than 1ms). This improves audio glitch
resistance at our current 512 sample buffer size, but going lower is
still not possible.
Imported functions in Wasm may throw JS exceptions, and we need to
preserve these exceptions so we can pass them to the calling JS code.
This also adds a `assert_wasm_result()` API to Result for cases where
only Wasm traps or values are expected (e.g. internal uses) to avoid
making LibWasm (pointlessly) handle JS exceptions that will never show
up in reality.
This adds the condition member.type->is_string() to the if statement, so
that we now conditionally check the dictionary member is a new string
and associated with an optional constructor parameter.
The LibWeb fuzzer build is really slow, so for local builds it is useful
to disable it when you're not interested in running that fuzzer.
Co-authored-by: Andrew Kaster <akaster@serenityos.org>
At the moment, this processes the RIFF chunk structure and extracts
the ICCP chunk, so that `icc` can now print ICC profiles embedded
in webp files. (And are image files really more than containers
of icc profiles?)
It doesn't even decode image dimensions yet.
The lossy format is a VP8 video frame. Once we get to that, we
might want to move all the image decoders into a new LibImageDecoders
that depends on both LibGfx and LibVideo. (Other newer image formats
like heic and av1f also use video frames for image data.)
This picks up any upstream brew changes that haven't been pulled into
the default Azure VMs. For example, the ffmpeg dependency of qt is
currently broken in the 8 day old brew commit they are using.
Make sure that we set SERENITY_SOURCE_DIR in ctest, and make sure to
pass the test root to the CI job.
More overhaul of test-js 'test root' finding is needed however.
When a constructor has an optional dictionary as argument, and those
members are of type new string, make sure that we release_value()
setting the dictionary members.
The patch also contains modifications on several classes, functions or
files that are related to the `JPGLoader`.
Renaming include:
- JPGLoader{.h, .cpp}
- JPGImageDecoderPlugin
- JPGLoadingContext
- JPG_DEBUG
- decode_jpg
- FuzzJPGLoader.cpp
- Few string literals or texts
This makes use of the new [UseNewAKString] extended attribute. Using
Vector storage will make it easier to make this interface into an IDL
iterable. It seems the reason it didn't use Vector originally was due
to awkward DeprecatedString -> String conversions.
Adding the [UseNewAKString] extended attribute to an interface will
cause all IDL string types to use String instead of DeprecatedString.
This is done on an per interface level instead of per type/parameter
because:
- It's much simpler to implement, as the generators can already access
the interface's extended attributes. Doing it per type/parameter
would mean parsing and piping extended attributes for each type that
doesn't already take extended attributes, such as unions.
- Allows more incremental adoption of AK::String. For example, adding
[UseNewAKString] to BodyInit would require refactoring Request,
Response and XMLHttpRequest to AK::String in one swoop. Doing it on
the interface allows you to convert just XHR and its dependencies at
once, for example.
- Simple string return types (i.e. not parameterised or not in a union)
already accept any of the string types JS::PrimitiveString::create
accepts. For example, you can add [UseNewAKString] to DOMStringMap to
convert Element attributes to AK::String and still return AK::String
from get_attribute, without adding [UseNewAKString] to Element.
- Adding [UseNewAKString] to one function typically means adding it to
a bunch of other functions, if not the rest of them. For example,
adding [UseNewAKString] to the parameters FormData.append would
either mean converting AK::String to AK::DeprecatedString or storing
the AK::String as-is, making the other functions of FormData have to
convert back from AK::String or also support AK::String.
This includes an Error::create overload to create an Error from a UTF-8
StringView. If creating a String from that view fails, the factory will
return an OOM InternalError instead. VM::throw_completion can also make
use of this overload via its perfect forwarding.
The aarch64 processor is set up to trap on unaligned memory accesses, so
to enforce that the compiler correctly generates aligned accesses, the
-mstrict-align flag is needed. We also need the -Wno-cast-align as there
are some files in AK that don't build without the flag.
The parser is still very much a work-in-progress, but it can currently
parse most of the basic bits, the only *completely* unimplemented things
in the parser are:
- heredocs (io_here)
- alias expansion
- arithmetic expansion
There are a whole suite of bugs, and syntax highlighting is unreliable
at best.
For now, this is not attached anywhere, a future commit will enable it
for /bin/sh or a `Shell --posix` invocation.
For example, consider cases where we want to propagate errors only in
specific instances:
auto result = read_data(); // something like ErrorOr<ByteBuffer>
if (result.is_error() && result.error().code() != EINTR)
continue;
auto bytes = TRY(result);
The TRY invocation will currently copy the byte buffer when the
expression (in this case, just a local variable) is stored into
_temporary_result.
This patch binds the expression to a reference to prevent such copies.
In less trival invocations (such as TRY(some_function()), this will
incur only temporary lifetime extensions, i.e. no functional change.
First, this adds an overload of PrimitiveString::create for StringView.
This overload will throw an OOM completion if creating a String fails.
This is not only a bit more convenient, but it also ensures at compile
time that all PrimitiveString::create(string_view) invocations will be
handled as String and OOM-aware.
Next, this wraps all invocations to PrimitiveString::create(string_view)
with MUST_OR_THROW_OOM.
A small PrimitiveString::create(DeprecatedFlyString) overload also had
to be added to disambiguate between the StringView and DeprecatedString
overloads.
This reverts commit b0606d90f0.
This seems to prevent libegl-mesa0 from being installed (which for some
reason isn't failing the Azure jobs - the failure seen later is that
ccache is not installed).
Previously the tool was removing the Root directory after configuring
cmake which was breaking the build, as some cmake rules put some
necessary files there.
Moving the cmake command to be the last one makes it regenerate those
files automatically. :^)
Setting the DWARF version after having selected which level of debug
information to generate apparently undoes some settings again.
Doing the reverse apparently keeps both the version and the debug level
setting, resulting in a significantly smaller disk image size.
Some tests, such as those under LibGL, try to load shared libraries at
runtime which are stored in Build/lagom. Because all tests' working
directory is that of their CMakeLists.txt file, they fail to find those
shared libraries at runtime.
Set LD_LIBRARY_PATH to Build/lagom so the tests may find the shared
libraries. This fixes, for example, both of these commands:
./Meta/serenity.sh test lagom TestAPI
./Meta/serenity.sh run lagom TestAPI
When we call add_test() from each test's CMakeLists.txt, we specify the
working directory to be that of the CMakeList.txt file itself. Create a
property to store that directory and reference it when run-lagom-target
is invoked by serenity.sh.
Note that for non-test Lagom targets which do not set this property, the
working directory will be Build/lagom (because the property will be the
empty string, which CMake resolves relative to the current build path).
The current config on GitHub Actions does not use ccache, so it takes
quite a while to build. Instead, let's just run these tests on Azure
where we already build Ladybird and have ccache enabled. This also lets
us sanitize LibWeb on both Linux and macOS.
The script changes here are to A) handle differences between Azure and
GitHub Actions and B) to support running on macOS.
They can be run using
Meta/serenity.sh test lagom TestFontHandling
which will build _all_ test binaries and then run TestFontHandling.
There's also
Meta/serenity.sh run lagom TestFontHandling
which will build just TestFontHandling and run it, but currently
in a way that it doesn't pass.
Finally, manually doing
Meta/serenity.sh build lagom TestFontHandling
followed by
(cd Tests/LibGfx; ../../Build/lagom/Tests/LibGfx/TestFontHandling)
will build and then run just that one test in a way that makes the test
pass.
`Stream` will be qualified as `AK::Stream` until we remove the
`Core::Stream` namespace. `IODevice` now reuses the `SeekMode` that is
defined by `SeekableStream`, since defining its own would require us to
qualify it with `AK::SeekMode` everywhere.
Note that as of this commit, there aren't any such throwers, and the
call site in Heap::allocate will drop exceptions on the floor. This
commit only serves to change the declaration of the overrides, make sure
they return an empty value, and to propagate OOM errors frm their base
initialize invocations.
Having an alias function that only wraps another one is silly, and
keeping the more obvious name should flush out more uses of deprecated
strings.
No behavior change.
After 5ac57f9, we could no longer run "serenity.sh run lagom TestString"
because the TestString binary now lives in a subdirectory under
Build/lagom. Thus the existing method of running "$BUILD_DIR/TestString"
could not work.
This adds a "run-lagom-target" custom target to Lagom, to run a command
and pass arguments to that invocation. It turns out there really isn't a
"pretty" way of doing this with CMake or Ninja. But we can pass these as
environment variables for CMake to interpret. We just must be careful to
massage arguments into a CMake list.
This makes sure that the aarch64 disk image also contains the correct
dynamic shared objects, specifically libgcc_s.so.1, as that one is a
dynamic dependency of every aarch64 executable.
To unify the x86_64 and aarch64 code paths, this commit just installs
everything from the compilers lib directory into the disk image lib
directory. This also happens for the Clang toolchain. This copies a few
extra files related to libsupc++ and libstdc++, increasing the size of
the disk image by 1.6MB. However, we were already copying libstdc++.a
manually anyway.
For now, this is limited to strings that are 3 bytes or less. We can use
7 bytes on 64-bit platforms, but we do not yet assume 64-bit for Lagom
hosts (e.g. wasm).
When trying to figure out the correct implementation, we now have a very
strong distinction on plugins that are well suited for sniffing, and
plugins that need a MIME type to be chosen.
Instead of having multiple calls to non-static virtual sniff methods for
each Image decoding plugin, we have 2 static methods for each
implementation:
1. The sniff method, which in contrast to the old method, gets a
ReadonlyBytes parameter and ensures we can figure out the result
with zero heap allocations for most implementations.
2. The create method, which just creates a new instance so we don't
expose the constructor to everyone anymore.
In addition to that, we have a new virtual method called initialize,
which has a per-implementation initialization pattern to actually ensure
each implementation can construct a decoder object, and then have a
correct context being applied to it for the actual decoding.
In order to prevent this commit from having to refactor almost all of
Intl, the goal here is to update the internal parsing/canonicalization
of locales within LibLocale only. Call sites which are already equiped
to handle String and OOM errors do so, however.
...mostly.
This creates and uses an override for the `serenity_test()` function, so
that Lagom can make use of the existing `Tests/LibFoo/CMakeLists.txt`
files instead of having to GLOB for test source files and manually copy
any data files.
Some GLOBs remain but this is most of them.
Co-authored-by: Andrew Kaster <akaster@serenityos.org>
The macOS FileWatcher depends on macOS dispatch queues, which run on a
different thread than the Core::EventLoop. This implementation handles
filesystem events on its dispatch queue, then forwards the event back to
the main Core::EventLoop for notifying the FileWatcher owner.
This includes:
- Moving it from Bindings/ to HTML/
- Renaming it from LocationObject to Location
- Removing the manual definitions of the constructor and prototype
- Removing special handling of the Location interface from the bindings
generator
- Converting the JS_DEFINE_NATIVE_FUNCTIONs to regular functions
returning DeprecatedString instead of PrimitiveString
- Adding missing (no-op) setters for the various attributes, which are
expected to exist by the bindings generator
Case folding rules have a similar mapping style as special casing rules,
where one code point may map to zero or more case folding rules. These
will be used for case-insensitive string comparisons. To see how case
folding can differ from other casing rules, consider "ß" (U+00DF):
>>> "ß".lower()
'ß'
>>> "ß".upper()
'SS'
>>> "ß".title()
'Ss'
>>> "ß".casefold()
'ss'
And remove links that aren't adding much value but will often get out of
date (i.e. links to UCD files, which are already all listed in
unicode_data.cmake).
This implements FileWatcher using inotify filesystem events. Serenity's
InodeWatcher is remarkably similar to inotify, so this is almost an
identical implementation.
The existing TestLibCoreFileWatcher test is added to Lagom (currently
just for Linux).
This does not implement BlockingFileWatcher as that is currently not
used anywhere but on Serenity.
If USING_AK_GLOBALLY is not defined, the name IsLvalueReference might
not be available in the global namespace. Follow the pattern established
in LibTest to fully qualify AK types in macros to avoid this problem.
The old approach was basically a linear scan, which is slower than a
hash map for the currently 303 elements, as evidenced by the new
benchmark in TestCSSIDSpeed.
Before: Completed benchmark 'value_id_from_string' in 3238ms
After: Completed benchmark 'value_id_from_string' in 193ms
This starts moving code equally shared between the OOPWV and Ladybird
WebContentView implementations to WebView::ViewImplementation, beginning
with the client state.
This utility when given a .tff font provides options for disassembling:
- The 'fpgm' table, this a program that's run once when the font is
loaded. It's used to define instructions and functions used by used
by other programs.
- The 'prep' table, this is a general program that's run when ever
the font size (or other properties) changes.
- And the programs associated with any individual glyph.
The disassembly is printed in a format that matches the examples from:
https://learn.microsoft.com/en-us/typography/opentype/spec/tt_instructions
I'm mainly adding this because I think it's neat to be able to look
at these things, and think it'll be helpful for debugging an
interpreter.
With this you can see that all of the LiberationSerif-XXX.tff fonts in
Serenity have these programs ready to go.
Currently, for each exposed interface, we generate one massive function
to create every Web constructor and prototype. In an effort to lazily
create these instead, this first step is to extract the creation of each
of these into its own method.
First, this generates a forwarding header for all IDL types. This is to
allow callers to remain unchanged without forcing them to include the
(very heavy) generated IDL headers. This header is included by LibWeb's
forwarding header.
Next, this defines a base template method on Web::Bindings::Intrinsics
to create a prototype/constructor pair. Specializations of this template
are now generated in a new .cpp file, IntrinsicDefinitions.cpp. The base
Intrinsics class is updated to use this new method, and will continue to
cache the result.
Last, some WebAssembly classes are updated to use this new mechanism.
They were using some ad hoc cache keys that are now in line with the
generated specializations.
That one massive function is still used to invoke these specializations,
so they are not lazy as of this commit.
Since AK can't refer to LibUnicode directly, the strategy here is that
if you need case transformations, you can link LibUnicode and receive
them. If you try to use either of these methods without linking it, then
you'll of course get a linker error (note we don't do any fallbacks to
e.g. ASCII case transformations). If you don't need these methods, you
don't have to link LibUnicode.
Nobody tests this network card as the person who added it, Jean-Baptiste
Boric (known as boricj) is not an active contributor in the project now.
After a discussion with him on the Discord server, we agreed it's for
the best to remove the driver, as for two reasons:
- The original author (boricj) agreed to do this, stating that he will
not be able to test the driver anymore after his Athlon XP machine is
no longer supported after the removal of the i686 port.
- It was agreed that the NE2000 network card family is far from the
ideal hardware we would want to support, similarly to the RTL8139 that
got removed recently for almost the same reason.
Previously, we had some broken cross-manpage links on the website after
the introduction of subsections. This is fixed by simply always using an
absolute path (leading '/') for links, making all images, icons and page
links work in all subsections.
Unfortunately, this change means that navigating the website build while
opening the files in the browser directly will no longer work. However,
a local static server such as `python -m http.server 8080` in the
output/ directory will work just fine for testing.
This will allow using images in manpages elsewhere in the future without
adjusting the PNG copying command.
rsync unfortunately cannot place all files into the root folder when
receiving a list of files via --files-from=-.
Nobody tests this network card, and the driver has bugs (see the issue
https://github.com/SerenityOS/serenity/issues/10198 for more details),
so it's almost certain that this happened due to code being rotting when
there's simply no testing of it.
Essentially this has been determined to be dead-code so this is the most
important reason to drop this code. Another good reason to do so is
because the RTL8139 only supports Fast Ethernet connections (10/100
Megabits per second), and is considered obsolete even for bare metal
setups.
This is required for me to be able to build both Serenity and
Ladybird from the same repo. Without this the two builds seem to
stomp on each other, then fail to link.
Generic PR actions include opening a PR, submit review comments, adding
new commits, etc. This prevents the reviewer and PR submitter from
having to manually bounce the labels back and forth in the general
case. The reviewer also may not have permission to set labels, meaning
the reviewer won't be able to update the labels accordingly themselves.
This does not handle more subjective labels such as pr-is-blocked and
pr-unclear. Unfortunately, there does not seem to be a GitHub Actions
trigger for when a PR has merge conflicts, so the pr-has-conflicts
label cannot be automatically applied.
Co-authored-by: kleines Filmröllchen <filmroellchen@serenityos.org>
The main point is to bring this in line with all the other file copying,
which is always done via rsync.
On my machine this leads to very little speedup, but I'm also on WSL, so
🤷
Timings:
Before:
Time (abs ≡): 20.440 s [User: 133.928 s, System: 12.290 s]
After:
Time (abs ≡): 20.346 s [User: 135.534 s, System: 11.207 s]
pandoc is a single-threaded and pretty slow application, so we can run
it in the background and "synchronize" before generating section
indices.
Timing results:
Before:
Time (abs ≡): 59.833 s [User: 49.541 s, System: 6.943 s]
After:
Time (abs ≡): 20.440 s [User: 133.928 s, System: 12.290 s]
(both generated with hyperfine -p "rm -r output || true" -r 1
Meta/build-manpages-website.sh )
For now, we create simple but complete indices and actually generate the
HTML for the manpages in subsections. For these purposes, switch to
using "find" as a file finding tool everywhere, instead of the very
limited globs from before.
This propagates errors from user-defined encoders up to IPC::Connection.
There, we currently just log the error, as we aren't in a position to
propagate it further (i.e. we are inside a deferred invocation).
These instances were detected by searching for files that include
AK/Format.h, but don't match the regex:
\\b(CheckedFormatString|critical_dmesgln|dbgln|dbgln_if|dmesgln|FormatBu
ilder|__FormatIfSupported|FormatIfSupported|FormatParser|FormatString|Fo
rmattable|Formatter|__format_value|HasFormatter|max_format_arguments|out
|outln|set_debug_enabled|StandardFormatter|TypeErasedFormatParams|TypeEr
asedParameter|VariadicFormatParams|v_critical_dmesgln|vdbgln|vdmesgln|vf
ormat|vout|warn|warnln|warnln_if)\\b
(Without the linebreaks.)
This regex is pessimistic, so there might be more files that don't
actually use any formatting functions.
Observe that this revealed that Userland/Libraries/LibC/signal.cpp is
missing an include.
In theory, one might use LibCPP to detect things like this
automatically, but let's do this one step after another.
This was useful when building both i686 and x86_64 SerenityOS targets as
we could use a single toolchain build for both targets. But now all this
extra job does is create the opportunity for the toolchain to need to be
built twice (i.e. if the pipelines are backed up and the toolchain cache
is busted between these jobs while the x86_64 step is waiting for a VM).
We currently don't support DWARF revision 5 and LLVM/Clang might create
such debug info into our binaries in x86_64, which will lead to a crash
in CrashReporter that is unable to parse that information correctly.
Currently, the generated IPC decoders will default-construct the type to
be decoded, then pass that value by reference to the concrete decoder.
This, of course, requires that the type is default-constructible. This
was an issue for decoding Variants, which had to require the first type
in the Variant list is Empty, to ensure it is default constructible.
Further, this made it possible for values to become uninitialized in
user-defined decoders.
This patch makes the decoder interface such that the concrete decoders
themselves contruct the decoded type upon return from the decoder. To do
so, the default decoders in IPC::Decoder had to be moved to the IPC
namespace scope, as these decoders are now specializations instead of
overloaded methods (C++ requires specializations to be in a namespace
scope).
This means that Ladybird can be built with either Meta/Lagom or Ladybird
as the top-level source directory. This setup is a bit awkward, but will
preserve the packaging story for Ladybird until we come up with a more
permanent solution.
They currently reside under Build/<arch>, meaning that they would be
redownloaded for each architecture/toolchain build combo. Move them to a
location that can be re-used for all builds.
The non-www domain does not appear to be available now. We use the www
domain for UCD.zip already.
Co-authored-by: Stephan Unverwerth <s.unverwerth@serenityos.org>
* `chmod -x` as it's for sourcing, not for executing
* Remove run line, for the same reason
* Rename it from .shell_include.sh to shell_include.sh, since e.g.
`rg` doesn't search in hidden files by default
No behavior change.
Rather than trying to assume the only two C libraries on Linux are musl
and glibc, this solution fixes musl builds by explicitly checking for
the one C library function we are overwriting.
That being said, we should find another solution to retrieving this
error information from crashing tests. Possibly just overriding the
SIGABRT handler would work. The full solution might require checking
stderr as well as stdout in the test driver though.
We now generate all LibGL API wrappers from a single API method
definition list stored in `GLAPI.json`. Since a significant portion of
the OpenGL API methods are relatively consistent variants, we take
advantage of this to generate a lot of these variants at once.
The autogenerated methods check for the non-nullness of the current
`GLContext`, and only perform an action if a `GLContext` is present.
This prevents a crash in ports like GLTron, who assume you can still
call the OpenGL API without an active context.
This increases our API wrapper method count from 211 to 356.
Fixes#15814.
...as long as `brew` is on the path and `brew --prefix e2fsprogs`
tells us where it is.
This is for people who don't have `"$(brew shellenv)"` in their .zshrc.
We previously disregarded Apple clang entirely, since no released
version was able to succesfully build Lagom. Xcode 14 seems to have
all the features we need, as we haven't added any code that needs
trunk clang features in quite a while.
This is to differentiate between the upcoming `AllocatingMemoryStream`,
which automatically allocates memory as needed instead of operating on a
static memory area.
Clean up the Wasm spec tests CMake rules to extract and compile the wat
files into wasm files in the LibWasm binary directory instead of its
source directory. Also make the rules more robust to missing host tools,
and use more CMake install rules for the test files rather than relying
on build-root-filesystem.sh. Add some FIXMEs for later, we really
shouldn't be doing installation of test files into /home/anon at the
build-root-filesystem stage in $CURRENT_YEAR. Tests go in /usr/Tests
This patch adds the `find_executable()` function that will hopefully
find executables in a distro-agnostic way and that is (hopefully as
well) easily upgradable.
The function uses some bash functionalities. So, we now require bash
for each script that includes `.shell_include.sh`.
We previously depended on sudo's specific -E flag to keep all the
environment variables when performing a privilege escalation. We now
incorporate the -E flag into the $SUDO variable, allowing for other
privilege escalation binaries (such as doas) to be used (as long as
they preserve the current environment variables).
This constructor was easily confused with a copy constructor, and it was
possible to accidentally copy-construct Objects in at least one way that
we dicovered (via generic ThrowCompletionOr construction).
This patch adds a mandatory ConstructWithPrototypeTag parameter to the
constructor to disambiguate it.
Tell CMake to not create a new policy scope for the
(lagom|serenity|common)_options.cmake helpers, and lets us set common
policies for both projects in common_options.cmake that actually apply
to the rest of the project, instead of just common_options.cmake itself.
Since we upstreamed CMake support for Serenity, we can use the Platform
files from upstream instead of keeping our local copy. While not added
in this commit, we can add patching capabilities for the platform files
similar to what we do for gdb, llvm, gcc, and binutils later.
This commit teaches BindingsGenerator to generate depfiles, which can be
used by CMake to ensure that bindings are properly regenerated when
imported IDL files change.
Two new options, `--depfile` and `--depfile-target` are added.
- `--depfile` sets the path for the dependency file.
- `--depfile-target` lets us set a target name different than the output
file in the depfile. This option is needed because generated files are
first written to a temporary file, but depfiles have to refer to the
final location.
These are analogous to GCC's `-MF` and `-MT` options respectively. The
depfile's syntax matches the ones generated by GCC.
Note: This changes the minimal required CMake version to 3.20 if the
Make generator is used, and to 3.21 for the Xcode generator. Ninja is
not affected.
This generally seems like a better name, especially if we somehow also
need a better name for "read the entire buffer, but not the entire file"
somewhere down the line.
Next to functions like `is_eof` these were really confusing to use, and
the `read`/`write` functions should fail anyways if a stream is not
readable/writable.
LibFuzzer documentation [1] states that all return values except for 0
and -1 are currently reserved for future use. -1 is a special return
value that causes LibFuzzer to not add a testing input to the testing
corpus, regardless of the code coverage that it causes.
[1] https://llvm.org/docs/LibFuzzer.html
This confused quite a number of people in the past, and it is still
slightly annoying to always switch the directory when testing both the
OS and the fuzzer build. Instead, let's just switch to the correct
directory automatically.
