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few corrections for guess_os_stack_limit() on OpenBSD #34

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few corrections for guess_os_stack_limit() on OpenBSD #34

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0123ca9
few corrections for guess_os_stack_limit() on OpenBSD
semarie May 9, 2020
3e9830a
allocate stack with MAP_STACK on OpenBSD
semarie May 9, 2020
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17 changes: 15 additions & 2 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -177,11 +177,24 @@ psm_stack_manipulation! {
old_stack_limit: get_stack_limit(),
};
let above_guard_page = new_stack.add(page_size);
#[cfg(not(target_os = "openbsd"))]
let result = libc::mprotect(
above_guard_page,
stack_bytes - page_size,
libc::PROT_READ | libc::PROT_WRITE
);
#[cfg(target_os = "openbsd")]
let result = if libc::mmap(
above_guard_page,
stack_bytes - page_size,
libc::PROT_READ | libc::PROT_WRITE,
libc::MAP_FIXED | libc::MAP_PRIVATE | libc::MAP_ANON | libc::MAP_STACK,
-1,
0) == above_guard_page {
0
} else {
-1
};
if result == -1 {
drop(guard);
panic!("unable to set stack permissions")
Expand Down Expand Up @@ -372,8 +385,8 @@ cfg_if! {
} else if #[cfg(target_os = "openbsd")] {
unsafe fn guess_os_stack_limit() -> Option<usize> {
let mut stackinfo = std::mem::MaybeUninit::<libc::stack_t>::uninit();
assert_eq!(libc::pthread_stackseg_np(libc::pthread_self(), stackinfo.as_mut_ptr()));
Some(stackinfo.assume_init().ss_sp)
assert_eq!(libc::pthread_stackseg_np(libc::pthread_self(), stackinfo.as_mut_ptr()), 0);
Some(stackinfo.assume_init().ss_sp as usize - stackinfo.assume_init().ss_size)
}
} else if #[cfg(target_os = "macos")] {
unsafe fn guess_os_stack_limit() -> Option<usize> {
Expand Down