1 //@ignore-target-windows: No libc on Windows
2 //! Test that pthread_key destructors are run in the right order.
3 //! Note that these are *not* used by actual `thread_local!` on Linux! Those use
4 //! `thread_local_dtor::register_dtor` from the stdlib instead. In Miri this hits the fallback path
5 //! in `register_dtor_fallback`, which uses a *single* pthread_key to manage a thread-local list of
11 pub type Key = libc::pthread_key_t;
13 static mut RECORD: usize = 0;
14 static mut KEYS: [Key; 2] = [0; 2];
15 static mut GLOBALS: [u64; 2] = [1, 0];
17 static mut CANNARY: *mut u64 = ptr::null_mut(); // this serves as a cannary: if TLS dtors are not run properly, this will not get deallocated, making the test fail.
19 pub unsafe fn create(dtor: Option<unsafe extern "C" fn(*mut u8)>) -> Key {
21 assert_eq!(libc::pthread_key_create(&mut key, mem::transmute(dtor)), 0);
25 pub unsafe fn set(key: Key, value: *mut u8) {
26 let r = libc::pthread_setspecific(key, value as *mut _);
30 pub fn record(r: usize) {
32 unsafe { RECORD = RECORD * 10 + r };
35 unsafe extern "C" fn dtor(ptr: *mut u64) {
36 assert!(CANNARY != ptr::null_mut()); // make sure we do not get run too often
40 GLOBALS.iter().position(|global| global as *const _ == ptr).expect("Should find my global");
45 set(KEYS[which_key], ptr as *mut _);
48 // Check if the records matches what we expect. If yes, clear the cannary.
49 // If the record is wrong, the cannary will never get cleared, leading to a leak -> test fails.
50 // If the record is incomplete (i.e., more dtor calls happen), the check at the beginning of this function will fail -> test fails.
51 // The correct sequence is: First key 0, then key 1, then key 0.
52 // Note that this relies on dtor order, which is not specified by POSIX, but seems to be
53 // consistent between Miri and Linux currently (as of Aug 2022).
55 drop(Box::from_raw(CANNARY));
56 CANNARY = ptr::null_mut();
62 create(None); // check that the no-dtor case works
64 // Initialize the keys we use to check destructor ordering
65 for (key, global) in KEYS.iter_mut().zip(GLOBALS.iter_mut()) {
66 *key = create(Some(mem::transmute(dtor as unsafe extern "C" fn(*mut u64))));
67 set(*key, global as *mut _ as *mut u8);
71 CANNARY = Box::into_raw(Box::new(0u64));