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Replace use of boxes with global allocator
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@elichai
elichai committed Aug 28, 2020
1 parent a00cb2a commit b09494f
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Showing 2 changed files with 36 additions and 30 deletions.
54 changes: 30 additions & 24 deletions src/context.rs
View file
@@ -1,7 +1,6 @@
use core::marker::PhantomData;
use core::mem::ManuallyDrop;
use ptr;
use ffi::{self, CPtr};
use core::mem::{self, ManuallyDrop};
use ffi::{self, CPtr, types::AlignedType};
use ffi::types::{c_uint, c_void};
use Error;
use Secp256k1;
Expand Down Expand Up @@ -49,7 +48,7 @@ pub unsafe trait Context : private::Sealed {
/// A constant description of the context.
const DESCRIPTION: &'static str;
/// A function to deallocate the memory when the context is dropped.
unsafe fn deallocate(ptr: *mut [u8]);
unsafe fn deallocate(ptr: *mut u8, size: usize);
}

/// Marker trait for indicating that an instance of `Secp256k1` can be used for signing.
Expand Down Expand Up @@ -92,6 +91,8 @@ mod std_only {
impl private::Sealed for VerifyOnly {}

use super::*;
use std::alloc;
const ALIGN_TO: usize = mem::align_of::<AlignedType>();

/// Represents the set of capabilities needed for signing.
pub enum SignOnly {}
Expand All @@ -112,26 +113,29 @@ mod std_only {
const FLAGS: c_uint = ffi::SECP256K1_START_SIGN;
const DESCRIPTION: &'static str = "signing only";

unsafe fn deallocate(ptr: *mut [u8]) {
let _ = Box::from_raw(ptr);
unsafe fn deallocate(ptr: *mut u8, size: usize) {
let layout = alloc::Layout::from_size_align(size, ALIGN_TO).unwrap();
alloc::dealloc(ptr, layout);
}
}

unsafe impl Context for VerifyOnly {
const FLAGS: c_uint = ffi::SECP256K1_START_VERIFY;
const DESCRIPTION: &'static str = "verification only";

unsafe fn deallocate(ptr: *mut [u8]) {
let _ = Box::from_raw(ptr);
unsafe fn deallocate(ptr: *mut u8, size: usize) {
let layout = alloc::Layout::from_size_align(size, ALIGN_TO).unwrap();
alloc::dealloc(ptr, layout);
}
}

unsafe impl Context for All {
const FLAGS: c_uint = VerifyOnly::FLAGS | SignOnly::FLAGS;
const DESCRIPTION: &'static str = "all capabilities";

unsafe fn deallocate(ptr: *mut [u8]) {
let _ = Box::from_raw(ptr);
unsafe fn deallocate(ptr: *mut u8, size: usize) {
let layout = alloc::Layout::from_size_align(size, ALIGN_TO).unwrap();
alloc::dealloc(ptr, layout);
}
}

Expand All @@ -141,12 +145,13 @@ mod std_only {
#[cfg(target_arch = "wasm32")]
ffi::types::sanity_checks_for_wasm();

let buf = vec![0u8; Self::preallocate_size_gen()].into_boxed_slice();
let ptr = Box::into_raw(buf);
let size = unsafe { ffi::secp256k1_context_preallocated_size(C::FLAGS) };
let layout = alloc::Layout::from_size_align(size, ALIGN_TO).unwrap();
let ptr = unsafe {alloc::alloc(layout)};
Secp256k1 {
ctx: unsafe { ffi::secp256k1_context_preallocated_create(ptr as *mut c_void, C::FLAGS) },
phantom: PhantomData,
buf: ptr,
size,
}
}
}
Expand Down Expand Up @@ -180,12 +185,13 @@ mod std_only {

impl<C: Context> Clone for Secp256k1<C> {
fn clone(&self) -> Secp256k1<C> {
let clone_size = unsafe {ffi::secp256k1_context_preallocated_clone_size(self.ctx)};
let ptr_buf = Box::into_raw(vec![0u8; clone_size].into_boxed_slice());
let size = unsafe {ffi::secp256k1_context_preallocated_clone_size(self.ctx as _)};
let layout = alloc::Layout::from_size_align(size, ALIGN_TO).unwrap();
let ptr = unsafe {alloc::alloc(layout)};
Secp256k1 {
ctx: unsafe { ffi::secp256k1_context_preallocated_clone(self.ctx, ptr_buf as *mut c_void) },
ctx: unsafe { ffi::secp256k1_context_preallocated_clone(self.ctx, ptr as *mut c_void) },
phantom: PhantomData,
buf: ptr_buf,
size,
}
}
}
Expand All @@ -201,7 +207,7 @@ unsafe impl<'buf> Context for SignOnlyPreallocated<'buf> {
const FLAGS: c_uint = ffi::SECP256K1_START_SIGN;
const DESCRIPTION: &'static str = "signing only";

unsafe fn deallocate(_ptr: *mut [u8]) {
unsafe fn deallocate(_ptr: *mut u8, _size: usize) {
// Allocated by the user
}
}
Expand All @@ -210,7 +216,7 @@ unsafe impl<'buf> Context for VerifyOnlyPreallocated<'buf> {
const FLAGS: c_uint = ffi::SECP256K1_START_VERIFY;
const DESCRIPTION: &'static str = "verification only";

unsafe fn deallocate(_ptr: *mut [u8]) {
unsafe fn deallocate(_ptr: *mut u8, _size: usize) {
// Allocated by the user
}
}
Expand All @@ -219,7 +225,7 @@ unsafe impl<'buf> Context for AllPreallocated<'buf> {
const FLAGS: c_uint = SignOnlyPreallocated::FLAGS | VerifyOnlyPreallocated::FLAGS;
const DESCRIPTION: &'static str = "all capabilities";

unsafe fn deallocate(_ptr: *mut [u8]) {
unsafe fn deallocate(_ptr: *mut u8, _size: usize) {
// Allocated by the user
}
}
Expand All @@ -240,7 +246,7 @@ impl<'buf, C: Context + 'buf> Secp256k1<C> {
C::FLAGS)
},
phantom: PhantomData,
buf: buf as *mut [u8],
size: 0, // We don't care about the size because it's the caller responsibility to deallocate.
})
}
}
Expand Down Expand Up @@ -270,7 +276,7 @@ impl<'buf> Secp256k1<AllPreallocated<'buf>> {
ManuallyDrop::new(Secp256k1 {
ctx: raw_ctx,
phantom: PhantomData,
buf: ptr::null_mut::<[u8;0]>() as *mut [u8] ,
size: 0, // We don't care about the size because it's the caller responsibility to deallocate.
})
}
}
Expand Down Expand Up @@ -302,7 +308,7 @@ impl<'buf> Secp256k1<SignOnlyPreallocated<'buf>> {
ManuallyDrop::new(Secp256k1 {
ctx: raw_ctx,
phantom: PhantomData,
buf: ptr::null_mut::<[u8;0]>() as *mut [u8] ,
size: 0, // We don't care about the size because it's the caller responsibility to deallocate.
})
}
}
Expand Down Expand Up @@ -334,7 +340,7 @@ impl<'buf> Secp256k1<VerifyOnlyPreallocated<'buf>> {
ManuallyDrop::new(Secp256k1 {
ctx: raw_ctx,
phantom: PhantomData,
buf: ptr::null_mut::<[u8;0]>() as *mut [u8] ,
size: 0, // We don't care about the size because it's the caller responsibility to deallocate.
})
}
}
12 changes: 6 additions & 6 deletions src/lib.rs
View file
Expand Up @@ -584,7 +584,7 @@ impl std::error::Error for Error {
pub struct Secp256k1<C: Context> {
ctx: *mut ffi::Context,
phantom: PhantomData<C>,
buf: *mut [u8],
size: usize,
}

// The underlying secp context does not contain any references to memory it does not own
Expand Down Expand Up @@ -633,7 +633,7 @@ impl<C: Context> Drop for Secp256k1<C> {
fn drop(&mut self) {
unsafe {
ffi::secp256k1_context_preallocated_destroy(self.ctx);
C::deallocate(self.buf);
C::deallocate(self.ctx as _, self.size);
}
}
}
Expand Down Expand Up @@ -813,10 +813,10 @@ mod tests {
let ctx_sign = unsafe { ffi::secp256k1_context_create(SignOnlyPreallocated::FLAGS) };
let ctx_vrfy = unsafe { ffi::secp256k1_context_create(VerifyOnlyPreallocated::FLAGS) };

let buf: *mut [u8] = &mut [0u8;0] as _;
let full: Secp256k1<AllPreallocated> = Secp256k1{ctx: ctx_full, phantom: PhantomData, buf};
let sign: Secp256k1<SignOnlyPreallocated> = Secp256k1{ctx: ctx_sign, phantom: PhantomData, buf};
let vrfy: Secp256k1<VerifyOnlyPreallocated> = Secp256k1{ctx: ctx_vrfy, phantom: PhantomData, buf};
let size = 0;
let full: Secp256k1<AllPreallocated> = Secp256k1{ctx: ctx_full, phantom: PhantomData, size};
let sign: Secp256k1<SignOnlyPreallocated> = Secp256k1{ctx: ctx_sign, phantom: PhantomData, size};
let vrfy: Secp256k1<VerifyOnlyPreallocated> = Secp256k1{ctx: ctx_vrfy, phantom: PhantomData, size};

let (sk, pk) = full.generate_keypair(&mut thread_rng());
let msg = Message::from_slice(&[2u8; 32]).unwrap();
Expand Down

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