* Add basic emulation of getcwd/chdir
This commit adds basic emulation of a current working directory to
wasi-libc. The `getcwd` and `chdir` symbols are now implemented and
available for use. The `getcwd` implementation is pretty simple in that
it just copies out of a new global, `__wasilibc_cwd`, which defaults to
`"/"`. The `chdir` implementation is much more involved and has more
ramification, however.
A new function, `make_absolute`, was added to the preopens object. Paths
stored in the preopen table are now always stored as absolute paths
instead of relative paths, and initial relative paths are interpreted as
being relative to `/`. Looking up a path to preopen now always turns it
into an absolute path, relative to the current working directory, and an
appropriate path is then returned.
The signature of `__wasilibc_find_relpath` has changed as well. It now
returns two path components, one for the absolute part and one for the
relative part. Additionally the relative part is always dynamically
allocated since it may no longer be a substring of the original input
path.
This has been tested lightly against the Rust standard library so far,
but I'm not a regular C developer so there's likely a few things to
improve!
* Amortize mallocs made in syscalls
* Avoid size bloat on programs that don't use `chdir`
* Add threading compat
* Collect `link`/`renameat` second path lookup
* Update comments about chdir.c in makefile
* Move definition of `__wasilibc_find_relpath_alloc` to header
* Expand comments
* Document the format of strings a bit more
* Fixup a few issues in path logic
* Fix GitHub Actions
This adds a new crt1-command.c startup file, which uses
[new-style command support]. Instead of calling `__wasm_call_ctors`
and `__wasm_call_dtors` directly, this lets wasm-ld automatically call
them.
This preserves the existing crt1.c, so that the same wasi-libc build
can support old-style and new-style commands, for compatibility during
the transition.
[new-style command support]: https://reviews.llvm.org/D81689
Co-authored-by: Dan Gohman <sunfish@mozilla.com>
Normally bits like this would be considered implementation details, but
in this case, `X_OK`, `W_OK`, and `R_OK` line up with `S_IXOTH`,
`S_IWOTH`, and `S_IROTH` on other systems, and those bits do have
well-known values.
This comments out a use of "protected" visibility, since
[WebAssembly doesn't support it].
[WebAssembly doesn't support it]: https://reviews.llvm.org/D81688
This emphasizes the relationship with `__wasm_call_ctors`. Note however
that while `__wasm_call_ctors` is synthesized by the linker,
`__wasm_call_dtors` is still defined by libc.
Static constructors are registered statically, but static destructors
need to be registered dynamically so that they only run if their
corresponding static constructors have run, and so that they're
ordered with respect to interleaved `atexit` calls.
* Avoid calling `poll_oneoff` with zero subscriptions.
With https://github.com/WebAssembly/WASI/pull/193 merged, WASI is moving
to make `poll_oneoff` with no arguments an error. Even though that's in
ephemeral and not yet in a snapshot, we can start to anticipate it in
libc:
- Remove the `pause` function, since WASI has no signals and thus no
way to ever wake it up short of having the host terminate it.
- Make `poll` and `pselect` return `ENOTSUP` in the case of having no
events to wait for.
* Remove `pause` from the defined-symbols.txt list.
* Fix __wasilibc_unmodified_upstream markers.
* Check for zero subscriptions, rather than zero events.
Make `poll` and `pselect` return `ENOTSUP` when asked to poll on zero
subscriptions, rather than when the systerm returns zero events.
While here, drop the `__wasilibc_unmodified_upstream` markers, which
were already pretty noisy here, and would be significantly worse with
this change.
* Add comments about the subtle relationship between nfds and nsubscriptions.
* Rewrite the comment.
* Fix code quotes.
* Rewrite the preopen functionality.
Rewrite the preopen functionality to be simpler, better organized,
and better integrated into WASI libc. Preopen support has diverged so
much from libpreopen that it no longer makes sense to track libpreopen
as an explicit upstream. And add more documentation.
* Fix missing #include.
* Fix a compilation error.
* Add support for the Reactor model.
* Mark _activate and _start as wasm exports.
* Rename _activate to _initialize.
* Don't define `_fini`.
* Rename reactor-crt1.c to crt1-reactor.c.
Before this commit, he header of a mapped area, `struct map`, was
defined as follows:
struct map {
int prot;
int flags;
off_t offset;
size_t length;
char body[];
};
Because the size and alignment of an `off_t` is 8 bytes, the entire
structure was padded to 24 bytes. However, the offset of `body` into
`struct map` was only 20 bytes. Therefore the code in mmap() and
munmap() did not agree on the offset from header to body.
This commit changes mmap() to skip the entire header, which is what
munmap() expects and what the size calculation uses.
* CI: use llvm 10.0.0 release
* ci: download mac over https, add -L flag to curl
* llvm 10 is shipping for ubuntu 18.04, which is reasonable
* llvm releases are now served from github! 🎉
* oops
* one of these days ill get it right
* love too program in yml
* missed the other spot to convert to 18.04
* mac ci: fix clang_dir
* Added utime.h
* Changes after code review
* Auto-generated expected files instead of manually editing
* Fix libpreopoen stat and utime not following symlinks correctly
* Use ?= for variables intended to be overridable.
* Use `override` consistently for variables not meant to be overridden.
* Omit miscellaneous comments from the build output.
* Tidy up some comments.
* Use `addprefix` to factor out a common prefix.
* Add a comment.
* Reorganize.
* Adjust indentation.
* Simplify the logic for the `check` rule.
* Remove the `override` keywords.
They theoretically protect what the Makefile considers to be
implementation details from being overridden on the command-line,
but in practice this isn't super important, and they add a lot of
clutter.
* Put source file names on their own lines.
* 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.
* Fix -std=gnu11 when generating predefined_macros.txt
The default recently changed in upstream clang:
https://reviews.llvm.org/D75383
We want to be immune to such things when generating this list so that
we can build wasi-libc with any recent clang version.
* 17
Update the description, point users to wasi-sdk as a simpler place to
get started using this library, and remove old text about being a
"reference" implementation.
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. The biggest change in musl is the
switch to 64-bit time_t for 32-bit targets, however WASI libc was already
using 64-bit time_t. The main change affecting WASI is an update to
Unicode 12.1.0.
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
Alex Crichton
Pat Hickey
Dan Gohman
vms
Dan Gohman
whitequark
Pat Hickey
Olaf Tomalka
Gabor Greif
Sam Clegg