Skip to content
Permalink
Browse files

wasi: Load arguments via syscalls

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!
  • Loading branch information...
alexcrichton committed Mar 31, 2019
1 parent eab3eb3 commit 382f9a7a3d15580c15531428f39bf47f55093d42
Showing with 24 additions and 26 deletions.
  1. +24 −26 src/libstd/sys/wasi/args.rs
@@ -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 {
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 _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())
})
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<_>>();
Args {
Ok(Args {
iter: args.into_iter(),
_dont_send_or_sync_me: PhantomData,
}
})
}
}

0 comments on commit 382f9a7

Please sign in to comment.
You can’t perform that action at this time.