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Add VarArgs type

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This commit is contained in:
Lachlan Sneff 2018-11-23 00:13:01 -05:00
parent 0d23a173c4
commit 587fb92de6
3 changed files with 31 additions and 27 deletions
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1
src/apis/emscripten/mod.rs
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@ -7,6 +7,7 @@ mod memory;
mod process;
mod syscalls;
mod utils;
mod varargs;
// SYSCALLS
pub use self::utils::is_emscripten_module;

42
src/apis/emscripten/syscalls.rs
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@ -3,59 +3,47 @@
use libc::{c_int, c_void, ssize_t, write};
use crate::webassembly::Instance;
// A macro to retrieve variadic arguments given a varargs offset
macro_rules! vararg {
($name:ident, $type:ident, $instance:ident, $varargs:ident) => (
let ($name, $varargs) = unsafe {
use std::ptr;
let ptr = $instance.memory_offset_addr(0, $varargs as usize);
let ret = ptr::read(ptr as *const $type);
(ret, $varargs + 4)
};
)
}
use super::varargs::VarArgs;
/// sys_read
pub extern "C" fn ___syscall3(_which: c_int, _varargs: c_int, _instance: &mut Instance) -> ssize_t {
pub extern "C" fn ___syscall3(_which: c_int, mut _varargs: VarArgs, _instance: &mut Instance) -> ssize_t {
debug!("emscripten::___syscall3");
0
}
/// sys_write
pub extern "C" fn ___syscall4(_which: c_int, varargs: c_int, instance: &mut Instance) -> c_int {
debug!("emscripten::___syscall4");
vararg!(fd, i32, instance, varargs);
vararg!(buf_ptr, u32, instance, varargs);
vararg!(count, u32, instance, varargs);
pub extern "C" fn ___syscall4(_which: c_int, mut varargs: VarArgs, instance: &mut Instance) -> c_int {
let fd: i32 = varargs.get(instance);
let buf_ptr: u32 = varargs.get(instance);
let count: u32 = varargs.get(instance);
debug!("fd: {}, buf_ptr: {}, count: {}", fd, buf_ptr, count);
let buf = instance.memory_offset_addr(0, buf_ptr as usize) as *const c_void;
unsafe { write(fd, buf, count as usize) as i32 }
}
/// sys_open
pub extern "C" fn ___syscall5(_which: c_int, varargs: c_int, instance: &mut Instance) -> c_int {
pub extern "C" fn ___syscall5(_which: c_int, mut varargs: VarArgs, instance: &mut Instance) -> c_int {
debug!("emscripten::___syscall5");
vararg!(pathname, u32, instance, varargs);
vararg!(flags, u32, instance, varargs);
vararg!(mode, u32, instance, varargs);
let pathname: u32 = varargs.get(instance);
let flags: u32 = varargs.get(instance);
let mode: u32 = varargs.get(instance);
debug!("pathname: {}, flags: {}, mode: {}", pathname, flags, mode);
-2
}
// sys_ioctl
pub extern "C" fn ___syscall54(_which: c_int, varargs: c_int, instance: &mut Instance) -> c_int {
pub extern "C" fn ___syscall54(_which: c_int, mut varargs: VarArgs, instance: &mut Instance) -> c_int {
debug!("emscripten::___syscall54");
vararg!(stream, u32, instance, varargs);
vararg!(op, u32, instance, varargs);
let stream: u32 = varargs.get(instance);
let op: u32 = varargs.get(instance);
debug!("stream: {}, op: {}", stream, op);
0
}
// sys_newuname
pub extern "C" fn ___syscall122(_which: c_int, varargs: c_int, instance: &mut Instance) -> c_int {
pub extern "C" fn ___syscall122(_which: c_int, mut varargs: VarArgs, instance: &mut Instance) -> c_int {
debug!("emscripten::___syscall122");
vararg!(buf, u32, instance, varargs);
let buf: u32 = varargs.get(instance);
debug!("buf: {}", buf);
0
}

15
src/apis/emscripten/varargs.rs Normal file
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@ -0,0 +1,15 @@
use crate::webassembly::Instance;
use std::mem;
#[repr(transparent)]
pub struct VarArgs {
pointer: u32, // assuming 32bit wasm
}
impl VarArgs {
pub fn get<T: Copy>(&mut self, instance: &mut Instance) -> T {
let ptr = instance.memory_offset_addr(0, self.pointer as usize);
self.pointer += mem::size_of::<T>() as u32;
unsafe { (ptr as *const T).read() }
}
}