Use num_enum crate for try_from(..)

Switch from derive-try-from-primitive crate
to num_enum crate in order to handle and
propagate errors more efficiently.

Author: ntegan1

Cargo.lock

@@ -13,7 +13,7 @@ std = []
 [dependencies]
 arrayvec = { version = "0.5.1", default-features = false }
 byteorder = { version = "1", default-features = false }
-derive-try-from-primitive = "0.1.0"
+num_enum = { version = "0.5.0", default-features = false }
 x86 = "0.27.0"
 log = { version = "0.4.8", default-features = false }
 bitflags = "1.2.0"
@@ -27,4 +27,4 @@ default-features = false
 features = ["no_std", "decoder"]
 
 [build-dependencies]
-nasm-rs = "0.1.7"
+nasm-rs = "0.1.7"

mythril_core/Cargo.lock

@@ -1,10 +1,11 @@
 use super::rsdt::SDT;
 use super::GenericAddressStructure;
-use crate::error::{Error, Result};
+use crate::error::Result;
 use byteorder::{ByteOrder, NativeEndian};
+use core::convert::TryFrom;
 use core::fmt;
 use core::ops::Range;
-use derive_try_from_primitive::TryFromPrimitive;
+use num_enum::TryFromPrimitive;
 
 mod offsets {
     use super::*;
@@ -68,14 +69,9 @@ impl<'a> HPET<'a> {
         let minimum_tick =
             NativeEndian::read_u16(&sdt.table[offsets::MIN_CLOCK_TICK]);
 
-        let page_protection =
-            PageProtection::try_from(sdt.table[offsets::PAGE_PROTECTION] & 0xF)
-                .ok_or_else(|| {
-                    Error::InvalidValue(format!(
-                        "Invalid HPET Page Protection type: {}",
-                        sdt.table[offsets::PAGE_PROTECTION] & 0xF
-                    ))
-                })?;
+        let page_protection = PageProtection::try_from(
+            sdt.table[offsets::PAGE_PROTECTION] & 0xF,
+        )?;
 
         let hardware_rev_id = (event_timer_block_id & 0xFF) as u8;
         let comparator_count = ((event_timer_block_id >> 8) & 0x1F) as u8;

mythril_core/Cargo.toml

@@ -2,9 +2,10 @@ use super::rsdt::SDT;
 use crate::error::{Error, Result};
 use bitflags::bitflags;
 use byteorder::{ByteOrder, NativeEndian};
+use core::convert::TryFrom;
 use core::fmt;
 use core::ops::Range;
-use derive_try_from_primitive::TryFromPrimitive;
+use num_enum::TryFromPrimitive;
 
 /// See Table 5-43 in the ACPI spcification.
 ///
@@ -334,8 +335,8 @@ impl<'a> Iterator for IcsIterator<'a> {
         }
 
         let ty = match IcsType::try_from(self.bytes[0]) {
-            Some(ty) => ty,
-            None => {
+            Ok(ty) => ty,
+            _ => {
                 return Some(Err(Error::InvalidValue(format!(
                     "Invalid ICS type: {}",
                     self.bytes[0]

mythril_core/src/acpi/hpet.rs

@@ -10,7 +10,8 @@
 
 use crate::error::{Error, Result};
 use byteorder::{ByteOrder, NativeEndian};
-use derive_try_from_primitive::TryFromPrimitive;
+use core::convert::TryFrom;
+use num_enum::TryFromPrimitive;
 use raw_cpuid::CpuId;
 
 /// Support for the High Precision Event Timer (HPET)
@@ -132,24 +133,13 @@ impl GenericAddressStructure {
         }
 
         let address_space =
-            AddressSpaceID::try_from(bytes[offsets::GAS_ADDRESS_SPACE])
-                .ok_or_else(|| {
-                    Error::InvalidValue(format!(
-                        "Invalid Address Space ID: {}",
-                        bytes[offsets::GAS_ADDRESS_SPACE]
-                    ))
-                })?;
+            AddressSpaceID::try_from(bytes[offsets::GAS_ADDRESS_SPACE])?;
 
         let bit_width = bytes[offsets::GAS_BIT_WIDTH];
         let bit_offset = bytes[offsets::GAS_BIT_OFFSET];
 
-        let access_size = AccessSize::try_from(bytes[offsets::GAS_ACCESS_SIZE])
-            .ok_or_else(|| {
-                Error::InvalidValue(format!(
-                    "Invalid Access Size: {}",
-                    bytes[offsets::GAS_ACCESS_SIZE]
-                ))
-            })?;
+        let access_size =
+            AccessSize::try_from(bytes[offsets::GAS_ACCESS_SIZE])?;
 
         let address = NativeEndian::read_u64(&bytes[offsets::GAS_ADDRESS]);
 

mythril_core/src/acpi/madt.rs

@@ -7,7 +7,7 @@ use alloc::boxed::Box;
 use alloc::collections::btree_map::BTreeMap;
 use alloc::vec::Vec;
 use core::convert::TryInto;
-use derive_try_from_primitive::TryFromPrimitive;
+use num_enum::TryFromPrimitive;
 use ux;
 
 #[derive(Clone, Copy, Debug, TryFromPrimitive)]

mythril_core/src/acpi/mod.rs

@@ -6,7 +6,7 @@ use crate::memory::GuestAddressSpaceViewMut;
 use alloc::boxed::Box;
 use alloc::vec::Vec;
 use core::convert::TryFrom;
-use derive_try_from_primitive::TryFromPrimitive;
+use num_enum::TryFromPrimitive;
 
 #[derive(Clone, Copy, Debug, TryFromPrimitive)]
 #[repr(u8)]

mythril_core/src/device/pci.rs

@@ -5,8 +5,8 @@ use crate::error::Result;
 use crate::memory::GuestAddressSpaceViewMut;
 use alloc::boxed::Box;
 use alloc::vec::Vec;
-use core::convert::TryInto;
-use derive_try_from_primitive::TryFromPrimitive;
+use core::convert::{TryFrom, TryInto};
+use num_enum::TryFromPrimitive;
 
 #[derive(Copy, Clone, Debug, TryFromPrimitive)]
 #[repr(u8)]

mythril_core/src/device/pit.rs

@@ -5,8 +5,8 @@ use crate::error::{Error, Result};
 use crate::memory::GuestAddressSpaceViewMut;
 use alloc::boxed::Box;
 use alloc::vec::Vec;
-use core::convert::TryInto;
-use derive_try_from_primitive::TryFromPrimitive;
+use core::convert::{TryFrom, TryInto};
+use num_enum::TryFromPrimitive;
 
 #[derive(Clone, Copy, Debug, TryFromPrimitive)]
 #[repr(u8)]
@@ -104,13 +104,7 @@ impl EmulatedDevice for VgaController {
         match port {
             Self::VGA_INDEX => match val {
                 PortWriteRequest::OneByte(b) => {
-                    self.index =
-                        VgaRegister::try_from(b[0]).ok_or_else(|| {
-                            Error::InvalidValue(format!(
-                                "Invalid vga register 0x{:x}",
-                                b[0]
-                            ))
-                        })?
+                    self.index = VgaRegister::try_from(b[0])?;
                 }
 
                 // The VGA controller allows a register update and data write
@@ -119,13 +113,7 @@ impl EmulatedDevice for VgaController {
                 PortWriteRequest::TwoBytes(bytes) => {
                     let index = bytes[1];
                     let data = bytes[0];
-                    self.index =
-                        VgaRegister::try_from(index).ok_or_else(|| {
-                            Error::InvalidValue(format!(
-                                "Invalid vga register 0x{:x}",
-                                index
-                            ))
-                        })?;
+                    self.index = VgaRegister::try_from(index)?;
                     self.registers[self.index as usize] = data;
                 }
                 _ => {