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|
//@ignore-target: windows # No pthreads on Windows
//@ignore-target: android # No pthread_{get,set}_name on Android
use std::ffi::{CStr, CString};
use std::thread;
const MAX_THREAD_NAME_LEN: usize = {
cfg_if::cfg_if! {
if #[cfg(any(target_os = "linux"))] {
16
} else if #[cfg(any(target_os = "illumos", target_os = "solaris"))] {
32
} else if #[cfg(target_os = "macos")] {
libc::MAXTHREADNAMESIZE // 64, at the time of writing
} else if #[cfg(target_os = "freebsd")] {
usize::MAX // as far as I can tell
} else {
panic!()
}
}
};
fn main() {
// The short name should be shorter than 16 bytes which POSIX promises
// for thread names. The length includes a null terminator.
let short_name = "test_named".to_owned();
let long_name = std::iter::once("test_named_thread_truncation")
.chain(std::iter::repeat(" yada").take(100))
.collect::<String>();
fn set_thread_name(name: &CStr) -> i32 {
cfg_if::cfg_if! {
if #[cfg(any(
target_os = "linux",
target_os = "freebsd",
target_os = "illumos",
target_os = "solaris"
))] {
unsafe { libc::pthread_setname_np(libc::pthread_self(), name.as_ptr().cast()) }
} else if #[cfg(target_os = "macos")] {
unsafe { libc::pthread_setname_np(name.as_ptr().cast()) }
} else {
compile_error!("set_thread_name not supported for this OS")
}
}
}
fn get_thread_name(name: &mut [u8]) -> i32 {
cfg_if::cfg_if! {
if #[cfg(any(
target_os = "linux",
target_os = "freebsd",
target_os = "illumos",
target_os = "solaris",
target_os = "macos"
))] {
unsafe {
libc::pthread_getname_np(libc::pthread_self(), name.as_mut_ptr().cast(), name.len())
}
} else {
compile_error!("get_thread_name not supported for this OS")
}
}
}
// Set name via Rust API, get it via pthreads.
let long_name2 = long_name.clone();
thread::Builder::new()
.name(long_name.clone())
.spawn(move || {
let mut buf = vec![0u8; long_name2.len() + 1];
assert_eq!(get_thread_name(&mut buf), 0);
let cstr = CStr::from_bytes_until_nul(&buf).unwrap();
let truncated_name = &long_name2[..long_name2.len().min(MAX_THREAD_NAME_LEN - 1)];
assert_eq!(cstr.to_bytes(), truncated_name.as_bytes());
})
.unwrap()
.join()
.unwrap();
// Set name via pthread and get it again (short name).
thread::Builder::new()
.spawn(move || {
// Set short thread name.
let cstr = CString::new(short_name.clone()).unwrap();
assert!(cstr.to_bytes_with_nul().len() <= MAX_THREAD_NAME_LEN); // this should fit
assert_eq!(set_thread_name(&cstr), 0);
// Now get it again, in various ways.
// POSIX seems to promise at least 15 chars excluding a null terminator.
let mut buf = vec![0u8; short_name.len().max(15) + 1];
assert_eq!(get_thread_name(&mut buf), 0);
let cstr = CStr::from_bytes_until_nul(&buf).unwrap();
assert_eq!(cstr.to_bytes(), short_name.as_bytes());
// Test what happens when the buffer is shorter than 16, but still long enough.
let res = get_thread_name(&mut buf[..15]);
cfg_if::cfg_if! {
if #[cfg(target_os = "linux")] {
// For glibc used by linux-gnu there should be a failue,
// if a shorter than 16 bytes buffer is provided, even if that would be
// large enough for the thread name.
assert_eq!(res, libc::ERANGE);
} else {
// Everywhere else, this should work.
assert_eq!(res, 0);
// POSIX seems to promise at least 15 chars excluding a null terminator.
let cstr = CStr::from_bytes_until_nul(&buf).unwrap();
assert_eq!(short_name.as_bytes(), cstr.to_bytes());
}
}
// Test what happens when the buffer is too short even for the short name.
let res = get_thread_name(&mut buf[..4]);
cfg_if::cfg_if! {
if #[cfg(any(target_os = "freebsd", target_os = "macos"))] {
// On macOS and FreeBSD it's not an error for the buffer to be
// too short for the thread name -- they truncate instead.
assert_eq!(res, 0);
let cstr = CStr::from_bytes_until_nul(&buf).unwrap();
assert_eq!(cstr.to_bytes_with_nul().len(), 4);
assert!(short_name.as_bytes().starts_with(cstr.to_bytes()));
} else {
// The rest should give an error.
assert_eq!(res, libc::ERANGE);
}
}
// Test zero-sized buffer.
let res = get_thread_name(&mut []);
cfg_if::cfg_if! {
if #[cfg(any(target_os = "freebsd", target_os = "macos"))] {
// On macOS and FreeBSD it's not an error for the buffer to be
// too short for the thread name -- even with size 0.
assert_eq!(res, 0);
} else {
// The rest should give an error.
assert_eq!(res, libc::ERANGE);
}
}
})
.unwrap()
.join()
.unwrap();
// Set name via pthread and get it again (long name).
thread::Builder::new()
.spawn(move || {
// Set full thread name.
let cstr = CString::new(long_name.clone()).unwrap();
let res = set_thread_name(&cstr);
cfg_if::cfg_if! {
if #[cfg(target_os = "freebsd")] {
// Names of all size are supported.
assert!(cstr.to_bytes_with_nul().len() <= MAX_THREAD_NAME_LEN);
assert_eq!(res, 0);
} else if #[cfg(target_os = "macos")] {
// Name is too long.
assert!(cstr.to_bytes_with_nul().len() > MAX_THREAD_NAME_LEN);
assert_eq!(res, libc::ENAMETOOLONG);
} else {
// Name is too long.
assert!(cstr.to_bytes_with_nul().len() > MAX_THREAD_NAME_LEN);
assert_eq!(res, libc::ERANGE);
}
}
// Set the longest name we can.
let truncated_name = &long_name[..long_name.len().min(MAX_THREAD_NAME_LEN - 1)];
let cstr = CString::new(truncated_name).unwrap();
assert_eq!(set_thread_name(&cstr), 0);
// Now get it again, in various ways.
// This name should round-trip properly.
let mut buf = vec![0u8; long_name.len() + 1];
assert_eq!(get_thread_name(&mut buf), 0);
let cstr = CStr::from_bytes_until_nul(&buf).unwrap();
assert_eq!(cstr.to_bytes(), truncated_name.as_bytes());
// Test what happens when our buffer is just one byte too small.
let res = get_thread_name(&mut buf[..truncated_name.len()]);
cfg_if::cfg_if! {
if #[cfg(any(target_os = "freebsd", target_os = "macos"))] {
// On macOS and FreeBSD it's not an error for the buffer to be
// too short for the thread name -- they truncate instead.
assert_eq!(res, 0);
let cstr = CStr::from_bytes_until_nul(&buf).unwrap();
assert_eq!(cstr.to_bytes(), &truncated_name.as_bytes()[..(truncated_name.len() - 1)]);
} else {
// The rest should give an error.
assert_eq!(res, libc::ERANGE);
}
}
})
.unwrap()
.join()
.unwrap();
// Now set the name for a non-existing thread and verify error codes.
let invalid_thread = 0xdeadbeef;
let error = {
cfg_if::cfg_if! {
if #[cfg(target_os = "linux")] {
libc::ENOENT
} else {
libc::ESRCH
}
}
};
#[cfg(not(target_os = "macos"))]
{
// macOS has no `setname` function accepting a thread id as the first argument.
let res = unsafe { libc::pthread_setname_np(invalid_thread, [0].as_ptr()) };
assert_eq!(res, error);
}
let mut buf = [0; 64];
let res = unsafe { libc::pthread_getname_np(invalid_thread, buf.as_mut_ptr(), buf.len()) };
assert_eq!(res, error);
}
|
