#[cfg(target_os = "linux")]
pub fn set_name(name: &CStr) {
+ const TASK_COMM_LEN: usize = 16;
+
unsafe {
// Available since glibc 2.12, musl 1.1.16, and uClibc 1.0.20.
+ let name = truncate_cstr(name, TASK_COMM_LEN);
libc::pthread_setname_np(libc::pthread_self(), name.as_ptr());
}
}
#[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
pub fn set_name(name: &CStr) {
unsafe {
+ let name = truncate_cstr(name, libc::MAXTHREADNAMESIZE);
libc::pthread_setname_np(name.as_ptr());
}
}
}
}
+#[cfg(any(target_os = "linux", target_os = "macos", target_os = "ios", target_os = "watchos"))]
+fn truncate_cstr(cstr: &CStr, max_with_nul: usize) -> crate::borrow::Cow<'_, CStr> {
+ use crate::{borrow::Cow, ffi::CString};
+
+ if cstr.to_bytes_with_nul().len() > max_with_nul {
+ let bytes = cstr.to_bytes()[..max_with_nul - 1].to_vec();
+ // SAFETY: the non-nul bytes came straight from a CStr.
+ // (CString will add the terminating nul.)
+ Cow::Owned(unsafe { CString::from_vec_unchecked(bytes) })
+ } else {
+ Cow::Borrowed(cstr)
+ }
+}
+
pub fn available_parallelism() -> io::Result<NonZeroUsize> {
cfg_if::cfg_if! {
if #[cfg(any(
fn min_stack_size(_: *const libc::pthread_attr_t) -> usize {
2048 // just a guess
}
+
+#[test]
+#[cfg(any(target_os = "linux", target_os = "macos", target_os = "ios", target_os = "watchos"))]
+fn test_named_thread_truncation() {
+ use crate::thread::{self, Builder};
+
+ let long_name = crate::iter::once("test_named_thread_truncation")
+ .chain(crate::iter::repeat(" yada").take(100))
+ .collect::<String>();
+
+ let result = Builder::new().name(long_name.clone()).spawn(move || {
+ // Rust remembers the full thread name itself.
+ assert_eq!(thread::current().name(), Some(long_name.as_str()));
+
+ // But the kernel is limited -- make sure we successfully set a truncation.
+ let mut buf = vec![0u8; long_name.len() + 1];
+ unsafe {
+ libc::pthread_getname_np(libc::pthread_self(), buf.as_mut_ptr().cast(), buf.len());
+ }
+ let cstr = CStr::from_bytes_until_nul(&buf).unwrap();
+ assert!(cstr.to_bytes().len() > 0);
+ assert!(long_name.as_bytes().starts_with(cstr.to_bytes()));
+ });
+ result.unwrap().join().unwrap();
+}