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.
`lseek(x, 0, SEEK_CUR)` has no effect other than to return the current
file offset. The patch here uses a macro with `__builtin_constant_p` to
recognize this case and rewrite it to a library call that uses `fd_tell`
rather than `fd_seek`, so that programs that don't need actual seeking
don't end up importing `fd_seek`.
This is also the first usage of `__wasi_fd_tell` in WASI libc, so this
adds it to undefined-symbols.txt.
Some systems, such as Darwin, only declare getentropy in <sys/random.h>,
so declare it there on WASI too for compatibility.
Also, give getentropy the underscore-prefix/weak-symbol treatment, as
it's not a standard-reserved identifier.
Previously, FD_SET and friends were missing their actual definitions.
This provides definitions, entirely within the system headers in a
way that doesn't need instantiated out-of-line definitions.
* Provide a public interface to preopened directory lookups.
For users of especially non-C compilers, provide an API for looking up
preopened directories. This is used internally in WASI libc to translate
from eg. `open` to `openat`, but it can now also be used by user code.
