* Lazy-initialize the environment variables.
This is the first in a series of PRs to make it easier to use WASI libc
in Wasm modules that don't have a `main` function. By initializing the
environment on demand, we avoid depending on having `__wasm_call_ctors`
run.
This uses weak symbols strategically to ensure that if `environ` is
used, it is initialized eagerly, but if only `getenv` and friends
are used, the environment is initialized lazily.
Eventually, I expect we'll have a convention for wasm modules without
main functions which will allow the `__wasm_call_ctors` function to be
called automatically, but this helps in simple cases for now.
Fixes#180.
* Add comments explaining the libc-environ-compat.h header usage.
This adds support for the `__main_argc_argv` change, while preserving
compatibility with `__original_main`. This is needed by the LTO build
because the `__original_main` hack works in LLVM codegen, which is after
LTO. The `__main_argc_argv` change is implemented in clang, which makes
it properly visible to LTO.
See the WHATSNEW file for details; this doesn't have any major changes
for wasi-libc; in particular, the new catgets and GLOB_TILDE features
are disabled.
we decided to abandon the upstream code guarded by
#ifdef __wasilibc_unmodified_upstream // non-anonymous unions
because these changes are sprawling and those guards are of diminishing
importance
* use pch/layout branch for witx; generate assertions of layout
* address review comments, add asserts for handle
* change wasm32 support comment to a preprocessor error
* expose `to_c_header` in wasi-headers crate for use in external test harness
* main.rs: inputs and output arguments are optional
so that generate-libc command works
* regen header
The header api.h was update using the following command:
$ cd tools/wasi-headers
$ cargo run -- WASI/phases/snapshot/witx/typenames.witx \
WASI/phases/snapshot/witx/wasi_snapshot_preview1.witx \
--output ../../libc-bottom-half/headers/public/wasi/api.h
This should probably have been part of #140 but we don't actually
support signals so this doesn't get much testing I imagine.
The old names like `__WASI_SIGBUS` no longer exist and the new names
look like `__WASI_SIGNAL_BUS`.
* Use constructor functions for optional init routines.
Instead of using weak symbols, use constructor function attributes for the
environment and preopen initialization routines. This is simpler, uses
less code, and is more LTO-friendly.
* Change the constructor priorities to start at 50.
We don't currently have specific plans for other levels in the reserved
range (0-100), so leave room for both lower and higher priorities.
* Add the WASI repo as a submodule.
Also, add the witx filenames to the generated output, and just have
`cargo run` auto-generate the api.h header, rather than using clap.
* Switch witx to a path dependency.
* Add a test.
* Add a test that the generated file is in sync with the generator.
* Enable CI testing with Github Actions.
* Fix the name of the wasi-headers directory.
* Enable submodules.
* Add a diff mechanism to help explain failures.
* Sort the inputs for display.
* More debugging.
* More debugging.
* Add a .gitattributes file forcing text files to be eol=lf.
Most editors these days can deal with eof=lf files, even on Windows, and
this avoids trouble with headers and other generated files differing in
line endings.
* Make __wasi_linkcount_t a uint64_t (#134)
Refs: https://github.com/WebAssembly/WASI/pull/127
* Generate the WASI interface from witx.
This replaces the hand-maintained <wasi/core.h> header with a
<wasi/api.h> generated from witx.
Most of the churn here is caused by upstream WASI renamings; hopefully
in the future ABI updates will be less noisy.
Don't ignore paths which don't have the required rights. This means
that if the lookup finds a path that doesn't have the required
rights, it'll just proceed to the actual operation which will fail
with `ENOTCAPABLE`.
Intuitively, use cases which would depend on having multiple
overlapping matching paths for a given lookup and intelligently
picking the one with the required rights seems like they should
be uncommon.
This is simpler overall, and requires less code.
Rely on the WASI implementation to check capabilities flags, rather
than also checking them in the userspace `openat` implementation.
This code is admittedly getting fairly dense with `#ifdef`s, so it
may soon make sense to move this file out of the `cloudlibc`
directory and removing the upstream change markers.
For now, this means using `//`-style comments in .c source files (though
not public header files), and spaces rather than tabs. No strong opinion
here; this is just what the majority of the current code is using.
This also synchronizes basics/crt/crt1.c with libc-bottom-half's
version, though this is just a cleanup as the former isn't currently used
by the main wasi-libc build.
* Avoid a `strdup` call in `__wasilibc_populate_libpreopen`.
Optimize `__wasilibc_populate_libpreopen` to avoid calling `strdup` in
the common case where it's called from `__wasilibc_populate_libpreopen`.
* Convert an if into a ?:.
wasi-libc's copy of libpreopen has evolved so many local changes that
it's no longer worth keeping the upstream code structure and marking
changes with __wasilibc_unmodified_upstream.
This PR merges the source files into a single file, removes all
__wasilibc_unmodified_upstream code, eliminates the ability to
allocate multiple preopen lists, eliminates the need for
__wasilibc_init_preopen, eliminates the non-standard eaccess, and
makes several other cleanups. It also enables NDEBUG so that internal
assertions are disabled in release builds.
POSIX requires `environ` to be a pointer to a NULL-terminated array of
pointers, so it itself can't be NULL.
This fixes a regression in src/functional/env.c in wasi-libc-test.
* Link `populate_args` only if we actually need command-line arguments.
This avoids linking in the argv/argc initialization code,
and the __wasi_args_sizes_get and __wasi_args_get imports, in
programs that don't use command-line arguments. The way this works is,
if the user writes `int main(int argc, char *argv[])`, the argument
initialization code is loaded, and if they write `int main(void)`,
it's not loaded.
This promotes the `__original_main` mechanism into an effective contract
between the compiler and libc, which wasn't its original purpose,
however it seems to fit this purpose quite well.
* Document that `__original_main` may be the user's zero-arg `main`.
* Link `populate_environ` only if we actually need environment variables.
This avoids linking in the environment variable initialization code,
and the __wasi_environ_sizes_get and __wasi_environ_get imports, in
programs that don't use environment variables.
This also removes the "___environ" (three underscores) alias symbol,
which is only in musl for backwards compatibility.
* Switch to //-style comments.
* If malloc fails, don't leave `__environ` pointing to an uninitialized buffer.
* Fix a memory leak if one malloc succeeds and the other fails.
* Use calloc to handle multiplication overflow.
This also handles the NULL terminator.
* Don't initialize __environ until everything has succeeded.
* Avoid leaking in case __wasi_environ_get fails.
* Handle overflow in the add too.
* Add #include <stdlib.h> for malloc etc.
* If the environment is empty, don't allocate any memory.
This replaces our custom `unlink` wrapper with an upstream one. We still
end up replacing the entire body with local changes, but this makes it
easier to see what those changes are.
The other change here is a fix to ignore repeated '/'s in paths.
POSIX requires fcntl.h to define the SEEK_* macros, so this satisfies
that requirement. Also, this allows <stdio.h> to avoid including as much
unnecessary content.
This fixes one issue with src/api/fcntl.c.
These functions aren't specific to the underlying system call interface,
so they don't need to be in the "bottom half".
This also fixes src/functional/inet_pton.c and
src/regression/inet_pton-empty-last-field.c in musl's libc-test.
Initialize `environ` even if there are no environment variables, so that
it alwasy points to a NULL-terminated array even if that array just
contains the NULL. This fixes src/functional/env.c.
