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wasi: Load arguments via syscalls

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This commit switches the wasi target to loading CLI arguments via the
syscalls provided by wasi rather than through the argc/argv passed to
the main function. While serving the same purpose it's hoped that using
syscalls will make us a bit more portable (less reliance from libstd on
an external C library) as well as avoiding the need for a lock!
This commit is contained in:
Alex Crichton 2019-03-31 14:39:03 -07:00
parent eab3eb38df
commit 382f9a7a3d
1 changed files with 25 additions and 27 deletions
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52
src/libstd/sys/wasi/args.rs
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@ -1,30 +1,15 @@
use crate::any::Any;
use crate::ffi::CStr;
use crate::io;
use crate::sys::cvt_wasi;
use crate::ffi::OsString;
use crate::marker::PhantomData;
use crate::os::wasi::ffi::OsStringExt;
use crate::ptr;
use crate::vec;
static mut ARGC: isize = 0;
static mut ARGV: *const *const u8 = ptr::null();
#[cfg(not(target_feature = "atomics"))]
pub unsafe fn args_lock() -> impl Any {
// No need for a lock if we're single-threaded, but this function will need
// to get implemented for multi-threaded scenarios
}
pub unsafe fn init(argc: isize, argv: *const *const u8) {
let _guard = args_lock();
ARGC = argc;
ARGV = argv;
pub unsafe fn init(_argc: isize, _argv: *const *const u8) {
}
pub unsafe fn cleanup() {
let _guard = args_lock();
ARGC = 0;
ARGV = ptr::null();
}
pub struct Args {
@ -34,18 +19,31 @@ pub struct Args {
/// Returns the command line arguments
pub fn args() -> Args {
unsafe {
let _guard = args_lock();
let args = (0..ARGC)
.map(|i| {
let cstr = CStr::from_ptr(*ARGV.offset(i) as *const libc::c_char);
OsStringExt::from_vec(cstr.to_bytes().to_vec())
})
.collect::<Vec<_>>();
maybe_args().unwrap_or_else(|_| {
Args {
iter: Vec::new().into_iter(),
_dont_send_or_sync_me: PhantomData
}
})
}
fn maybe_args() -> io::Result<Args> {
unsafe {
let (mut argc, mut argv_buf_size) = (0, 0);
cvt_wasi(libc::__wasi_args_sizes_get(&mut argc, &mut argv_buf_size))?;
let mut argc = vec![0 as *mut libc::c_char; argc];
let mut argv_buf = vec![0; argv_buf_size];
cvt_wasi(libc::__wasi_args_get(argc.as_mut_ptr(), argv_buf.as_mut_ptr()))?;
let args = argc.into_iter()
.map(|ptr| CStr::from_ptr(ptr).to_bytes().to_vec())
.map(|bytes| OsString::from_vec(bytes))
.collect::<Vec<_>>();
Ok(Args {
iter: args.into_iter(),
_dont_send_or_sync_me: PhantomData,
}
})
}
}