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Add experimental struct with views memory and ctxs

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This struct is heavily taking from Lucet's Vmctx struct.
This commit is contained in:
Jakub Konka
2019-05-10 20:13:50 +02:00
parent 328b8f3d91
commit 751a1a1f7b
5 changed files with 202 additions and 103 deletions
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63
src/memory.rs
View File

@@ -9,7 +9,7 @@
//!
//! This sort of manual encoding will hopefully be obsolete once the IDL is developed.
use crate::ctx::VmContext;
use crate::vmctx::VmContextView;
use crate::{host, wasm32};
use cast;
@@ -23,26 +23,47 @@ macro_rules! bail_errno {
};
}
pub unsafe fn dec_ptr(
vmctx: &VmContextView,
ptr: wasm32::uintptr_t,
len: usize,
) -> Result<*mut u8, host::__wasi_errno_t> {
let mut heap = vmctx.memory_mut();
// check that `len` fits in the wasm32 address space
if len > wasm32::UINTPTR_MAX as usize {
bail_errno!(__WASI_EOVERFLOW);
}
// check that `ptr` and `ptr + len` are both within the guest heap
if ptr as usize > heap.len() || ptr as usize + len > heap.len() {
bail_errno!(__WASI_EFAULT);
}
// translate the pointer
Ok(heap.as_mut_ptr().offset(ptr as isize))
}
pub unsafe fn dec_ptr_to<T>(
vmctx: *mut VmContext,
vmctx: &VmContextView,
ptr: wasm32::uintptr_t,
) -> Result<*mut T, host::__wasi_errno_t> {
// check that the ptr is aligned
if ptr as usize % align_of::<T>() != 0 {
bail_errno!(__WASI_EINVAL);
}
(*vmctx).dec_ptr(ptr, size_of::<T>()).map(|p| p as *mut T)
dec_ptr(vmctx, ptr, size_of::<T>()).map(|p| p as *mut T)
}
pub unsafe fn dec_pointee<T>(
vmctx: *mut VmContext,
vmctx: &VmContextView,
ptr: wasm32::uintptr_t,
) -> Result<T, host::__wasi_errno_t> {
dec_ptr_to::<T>(vmctx, ptr).map(|p| p.read())
}
pub unsafe fn enc_pointee<T>(
vmctx: *mut VmContext,
vmctx: &VmContextView,
ptr: wasm32::uintptr_t,
t: T,
) -> Result<(), host::__wasi_errno_t> {
@@ -50,7 +71,7 @@ pub unsafe fn enc_pointee<T>(
}
pub unsafe fn dec_slice_of<T>(
vmctx: *mut VmContext,
vmctx: &VmContextView,
ptr: wasm32::uintptr_t,
len: wasm32::size_t,
) -> Result<(*mut T, usize), host::__wasi_errno_t> {
@@ -65,13 +86,13 @@ pub unsafe fn dec_slice_of<T>(
return Err(host::__WASI_EOVERFLOW);
};
let ptr = (*vmctx).dec_ptr(ptr, len_bytes)? as *mut T;
let ptr = dec_ptr(vmctx, ptr, len_bytes)? as *mut T;
Ok((ptr, len))
}
pub unsafe fn enc_slice_of<T>(
vmctx: *mut VmContext,
vmctx: &VmContextView,
slice: &[T],
ptr: wasm32::uintptr_t,
) -> Result<(), host::__wasi_errno_t> {
@@ -87,7 +108,7 @@ pub unsafe fn enc_slice_of<T>(
};
// get the pointer into guest memory, and copy the bytes
let ptr = (*vmctx).dec_ptr(ptr, len_bytes)? as *mut libc::c_void;
let ptr = dec_ptr(vmctx, ptr, len_bytes)? as *mut libc::c_void;
libc::memcpy(ptr, slice.as_ptr() as *const libc::c_void, len_bytes);
Ok(())
@@ -100,7 +121,7 @@ macro_rules! dec_enc_scalar {
}
pub unsafe fn $dec_byref(
vmctx: *mut VmContext,
vmctx: &VmContextView,
ptr: wasm32::uintptr_t,
) -> Result<host::$ty, host::__wasi_errno_t> {
dec_pointee::<wasm32::$ty>(vmctx, ptr).map($dec)
@@ -111,7 +132,7 @@ macro_rules! dec_enc_scalar {
}
pub unsafe fn $enc_byref(
vmctx: *mut VmContext,
vmctx: &VmContextView,
ptr: wasm32::uintptr_t,
x: host::$ty,
) -> Result<(), host::__wasi_errno_t> {
@@ -121,18 +142,18 @@ macro_rules! dec_enc_scalar {
}
pub unsafe fn dec_ciovec(
vmctx: *mut VmContext,
vmctx: &VmContextView,
ciovec: &wasm32::__wasi_ciovec_t,
) -> Result<host::__wasi_ciovec_t, host::__wasi_errno_t> {
let len = dec_usize(ciovec.buf_len);
Ok(host::__wasi_ciovec_t {
buf: (*vmctx).dec_ptr(ciovec.buf, len)? as *const host::void,
buf: dec_ptr(vmctx, ciovec.buf, len)? as *const host::void,
buf_len: len,
})
}
pub unsafe fn dec_ciovec_slice(
vmctx: *mut VmContext,
vmctx: &VmContextView,
ptr: wasm32::uintptr_t,
len: wasm32::size_t,
) -> Result<Vec<host::__wasi_ciovec_t>, host::__wasi_errno_t> {
@@ -206,7 +227,7 @@ pub fn dec_filestat(filestat: wasm32::__wasi_filestat_t) -> host::__wasi_filesta
}
pub unsafe fn dec_filestat_byref(
vmctx: *mut VmContext,
vmctx: &VmContextView,
filestat_ptr: wasm32::uintptr_t,
) -> Result<host::__wasi_filestat_t, host::__wasi_errno_t> {
dec_pointee::<wasm32::__wasi_filestat_t>(vmctx, filestat_ptr).map(dec_filestat)
@@ -226,7 +247,7 @@ pub fn enc_filestat(filestat: host::__wasi_filestat_t) -> wasm32::__wasi_filesta
}
pub unsafe fn enc_filestat_byref(
vmctx: *mut VmContext,
vmctx: &VmContextView,
filestat_ptr: wasm32::uintptr_t,
host_filestat: host::__wasi_filestat_t,
) -> Result<(), host::__wasi_errno_t> {
@@ -244,7 +265,7 @@ pub fn dec_fdstat(fdstat: wasm32::__wasi_fdstat_t) -> host::__wasi_fdstat_t {
}
pub unsafe fn dec_fdstat_byref(
vmctx: *mut VmContext,
vmctx: &VmContextView,
fdstat_ptr: wasm32::uintptr_t,
) -> Result<host::__wasi_fdstat_t, host::__wasi_errno_t> {
dec_pointee::<wasm32::__wasi_fdstat_t>(vmctx, fdstat_ptr).map(dec_fdstat)
@@ -261,7 +282,7 @@ pub fn enc_fdstat(fdstat: host::__wasi_fdstat_t) -> wasm32::__wasi_fdstat_t {
}
pub unsafe fn enc_fdstat_byref(
vmctx: *mut VmContext,
vmctx: &VmContextView,
fdstat_ptr: wasm32::uintptr_t,
host_fdstat: host::__wasi_fdstat_t,
) -> Result<(), host::__wasi_errno_t> {
@@ -328,7 +349,7 @@ pub fn dec_prestat(
}
pub unsafe fn dec_prestat_byref(
vmctx: *mut VmContext,
vmctx: &VmContextView,
prestat_ptr: wasm32::uintptr_t,
) -> Result<host::__wasi_prestat_t, host::__wasi_errno_t> {
dec_pointee::<wasm32::__wasi_prestat_t>(vmctx, prestat_ptr).and_then(dec_prestat)
@@ -354,7 +375,7 @@ pub fn enc_prestat(
}
pub unsafe fn enc_prestat_byref(
vmctx: *mut VmContext,
vmctx: &VmContextView,
prestat_ptr: wasm32::uintptr_t,
host_prestat: host::__wasi_prestat_t,
) -> Result<(), host::__wasi_errno_t> {
@@ -386,7 +407,7 @@ pub fn enc_usize(size: usize) -> wasm32::size_t {
}
pub unsafe fn enc_usize_byref(
vmctx: *mut VmContext,
vmctx: &VmContextView,
usize_ptr: wasm32::uintptr_t,
host_usize: usize,
) -> Result<(), host::__wasi_errno_t> {