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https://github.com/bspeice/qadapt
synced 2024-11-21 13:28:11 -05:00
Docs updates and thread_id crate
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@ -12,5 +12,6 @@ repository = "https://github.com/bspeice/qadapt.git"
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libc = "0.2"
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log = "0.4"
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spin = "0.4"
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thread-id = "3.3"
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qadapt-macro = { path = "./qadapt-macro" }
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42
src/lib.rs
42
src/lib.rs
@ -9,10 +9,15 @@
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//! recommended that QADAPT (the allocator) be used only in code tests. Functions annotated with
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//! `#[allocate_panic]` will have no side effects if the QADAPT allocator is not being used,
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//! so the attribute is safe to leave everywhere.
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//!
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//! Currently this crate is Nightly-only, but will work once `const fn` is in Stable.
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#![deny(missing_docs)]
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extern crate libc;
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extern crate qadapt_macro;
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extern crate spin;
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// thread_id is necessary because `std::thread::current()` panics if we have not yet
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// allocated a `thread_local!{}` it depends on.
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extern crate thread_id;
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// Re-export the proc macros to use by other code
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pub use qadapt_macro::*;
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@ -20,14 +25,13 @@ pub use qadapt_macro::*;
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use libc::c_void;
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use libc::free;
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use libc::malloc;
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use libc::pthread_self;
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use spin::RwLock;
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use std::alloc::Layout;
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use std::alloc::GlobalAlloc;
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use std::thread;
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thread_local! {
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static PROTECTION_LEVEL: RwLock<u32> = RwLock::new(0);
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static PROTECTION_LEVEL: RwLock<usize> = RwLock::new(0);
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}
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/// The QADAPT allocator itself
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@ -63,37 +67,29 @@ pub fn exit_protected() {
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}).unwrap_or_else(|_e| ());
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}
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static INTERNAL_ALLOCATION: RwLock<u64> = RwLock::new(u64::max_value());
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static INTERNAL_ALLOCATION: RwLock<usize> = RwLock::new(usize::max_value());
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unsafe fn claim_internal_alloc() -> u64 {
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// std::thread::current() isn't safe because of thread-local allocations
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let tid = pthread_self();
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unsafe fn claim_internal_alloc() {
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loop {
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match INTERNAL_ALLOCATION.write() {
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ref mut lock if **lock == u64::max_value() => {
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**lock = tid;
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ref mut lock if **lock == usize::max_value() => {
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**lock = thread_id::get();
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break
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},
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_ => ()
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}
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}
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tid
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}
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unsafe fn release_internal_alloc() -> u64 {
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let tid = pthread_self();
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// TODO: Potential issues with releasing lock too early?
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unsafe fn release_internal_alloc() {
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match INTERNAL_ALLOCATION.write() {
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ref mut lock if **lock == tid => **lock = u64::max_value(),
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ref mut lock if **lock == thread_id::get() => **lock = usize::max_value(),
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_ => panic!("Internal allocation tracking error")
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}
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tid
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}
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unsafe fn alloc_immediate() -> bool {
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thread::panicking() || *INTERNAL_ALLOCATION.read() == pthread_self()
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thread::panicking() || *INTERNAL_ALLOCATION.read() == thread_id::get()
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}
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unsafe impl GlobalAlloc for QADAPT {
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@ -107,21 +103,18 @@ unsafe impl GlobalAlloc for QADAPT {
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// Because accessing PROTECTION_LEVEL has the potential to trigger an allocation,
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// we need to spin until we can claim the INTERNAL_ALLOCATION lock for our thread.
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claim_internal_alloc();
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let protection_level: Result<u32, ()> = PROTECTION_LEVEL.try_with(|v| *v.read()).or(Ok(0));
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let protection_level: Result<usize, ()> = PROTECTION_LEVEL.try_with(|v| *v.read()).or(Ok(0));
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release_internal_alloc();
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match protection_level {
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Ok(v) if v == 0 => malloc(layout.size()) as *mut u8,
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Ok(v) => {
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// Tripped a bad allocation, but make sure further allocation/deallocation during unwind
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// Tripped a bad allocation, but make sure further memory access during unwind
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// doesn't have issues
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PROTECTION_LEVEL.with(|v| *v.write() = 0);
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panic!("Unexpected allocation for size {}, protection level: {}", layout.size(), v)
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},
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Err(_) => {
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// Shouldn't be possible to get here
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panic!("Unexpected error checking protection level")
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}
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Err(_) => unreachable!()
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}
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}
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@ -131,9 +124,10 @@ unsafe impl GlobalAlloc for QADAPT {
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}
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claim_internal_alloc();
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let protection_level: Result<u32, ()> = PROTECTION_LEVEL.try_with(|v| *v.read()).or(Ok(0));
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let protection_level: Result<usize, ()> = PROTECTION_LEVEL.try_with(|v| *v.read()).or(Ok(0));
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release_internal_alloc();
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// Free before checking panic to make sure we avoid leaks
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free(ptr as *mut c_void);
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match protection_level {
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Ok(v) if v > 0 => {
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@ -86,4 +86,12 @@ fn test_vec_new() {
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fn test_vec_with_one() {
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enter_protected();
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let _v: Vec<u8> = Vec::with_capacity(1);
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}
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#[test]
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#[should_panic]
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fn exit_too_often() {
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enter_protected();
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exit_protected();
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exit_protected();
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}
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