| use crate::cmp; |
| use crate::ffi::CStr; |
| use crate::io; |
| use crate::mem; |
| use crate::num::NonZeroUsize; |
| use crate::ptr; |
| use crate::sys::{os, stack_overflow}; |
| use crate::time::Duration; |
| |
| #[cfg(all(target_os = "linux", target_env = "gnu"))] |
| use crate::sys::weak::dlsym; |
| #[cfg(any(target_os = "solaris", target_os = "illumos"))] |
| use crate::sys::weak::weak; |
| #[cfg(not(any(target_os = "l4re", target_os = "vxworks", target_os = "espidf")))] |
| pub const DEFAULT_MIN_STACK_SIZE: usize = 2 * 1024 * 1024; |
| #[cfg(target_os = "l4re")] |
| pub const DEFAULT_MIN_STACK_SIZE: usize = 1024 * 1024; |
| #[cfg(target_os = "vxworks")] |
| pub const DEFAULT_MIN_STACK_SIZE: usize = 256 * 1024; |
| #[cfg(target_os = "espidf")] |
| pub const DEFAULT_MIN_STACK_SIZE: usize = 0; // 0 indicates that the stack size configured in the ESP-IDF menuconfig system should be used |
| |
| #[cfg(target_os = "fuchsia")] |
| mod zircon { |
| type zx_handle_t = u32; |
| type zx_status_t = i32; |
| pub const ZX_PROP_NAME: u32 = 3; |
| |
| extern "C" { |
| pub fn zx_object_set_property( |
| handle: zx_handle_t, |
| property: u32, |
| value: *const libc::c_void, |
| value_size: libc::size_t, |
| ) -> zx_status_t; |
| pub fn zx_thread_self() -> zx_handle_t; |
| } |
| } |
| |
| pub struct Thread { |
| id: libc::pthread_t, |
| } |
| |
| // Some platforms may have pthread_t as a pointer in which case we still want |
| // a thread to be Send/Sync |
| unsafe impl Send for Thread {} |
| unsafe impl Sync for Thread {} |
| |
| impl Thread { |
| // unsafe: see thread::Builder::spawn_unchecked for safety requirements |
| pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> { |
| let p = Box::into_raw(box p); |
| let mut native: libc::pthread_t = mem::zeroed(); |
| let mut attr: libc::pthread_attr_t = mem::zeroed(); |
| assert_eq!(libc::pthread_attr_init(&mut attr), 0); |
| |
| #[cfg(target_os = "espidf")] |
| if stack > 0 { |
| // Only set the stack if a non-zero value is passed |
| // 0 is used as an indication that the default stack size configured in the ESP-IDF menuconfig system should be used |
| assert_eq!( |
| libc::pthread_attr_setstacksize(&mut attr, cmp::max(stack, min_stack_size(&attr))), |
| 0 |
| ); |
| } |
| |
| #[cfg(not(target_os = "espidf"))] |
| { |
| let stack_size = cmp::max(stack, min_stack_size(&attr)); |
| |
| match libc::pthread_attr_setstacksize(&mut attr, stack_size) { |
| 0 => {} |
| n => { |
| assert_eq!(n, libc::EINVAL); |
| // EINVAL means |stack_size| is either too small or not a |
| // multiple of the system page size. Because it's definitely |
| // >= PTHREAD_STACK_MIN, it must be an alignment issue. |
| // Round up to the nearest page and try again. |
| let page_size = os::page_size(); |
| let stack_size = |
| (stack_size + page_size - 1) & (-(page_size as isize - 1) as usize - 1); |
| assert_eq!(libc::pthread_attr_setstacksize(&mut attr, stack_size), 0); |
| } |
| }; |
| } |
| |
| let ret = libc::pthread_create(&mut native, &attr, thread_start, p as *mut _); |
| // Note: if the thread creation fails and this assert fails, then p will |
| // be leaked. However, an alternative design could cause double-free |
| // which is clearly worse. |
| assert_eq!(libc::pthread_attr_destroy(&mut attr), 0); |
| |
| return if ret != 0 { |
| // The thread failed to start and as a result p was not consumed. Therefore, it is |
| // safe to reconstruct the box so that it gets deallocated. |
| drop(Box::from_raw(p)); |
| Err(io::Error::from_raw_os_error(ret)) |
| } else { |
| Ok(Thread { id: native }) |
| }; |
| |
| extern "C" fn thread_start(main: *mut libc::c_void) -> *mut libc::c_void { |
| unsafe { |
| // Next, set up our stack overflow handler which may get triggered if we run |
| // out of stack. |
| let _handler = stack_overflow::Handler::new(); |
| // Finally, let's run some code. |
| Box::from_raw(main as *mut Box<dyn FnOnce()>)(); |
| } |
| ptr::null_mut() |
| } |
| } |
| |
| pub fn yield_now() { |
| let ret = unsafe { libc::sched_yield() }; |
| debug_assert_eq!(ret, 0); |
| } |
| |
| #[cfg(target_os = "android")] |
| pub fn set_name(name: &CStr) { |
| const PR_SET_NAME: libc::c_int = 15; |
| unsafe { |
| libc::prctl( |
| PR_SET_NAME, |
| name.as_ptr(), |
| 0 as libc::c_ulong, |
| 0 as libc::c_ulong, |
| 0 as libc::c_ulong, |
| ); |
| } |
| } |
| |
| #[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); |
| let res = libc::pthread_setname_np(libc::pthread_self(), name.as_ptr()); |
| // We have no good way of propagating errors here, but in debug-builds let's check that this actually worked. |
| debug_assert_eq!(res, 0); |
| } |
| } |
| |
| #[cfg(any(target_os = "freebsd", target_os = "dragonfly", target_os = "openbsd"))] |
| pub fn set_name(name: &CStr) { |
| unsafe { |
| libc::pthread_set_name_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); |
| let res = libc::pthread_setname_np(name.as_ptr()); |
| // We have no good way of propagating errors here, but in debug-builds let's check that this actually worked. |
| debug_assert_eq!(res, 0); |
| } |
| } |
| |
| #[cfg(target_os = "netbsd")] |
| pub fn set_name(name: &CStr) { |
| unsafe { |
| let cname = CStr::from_bytes_with_nul_unchecked(b"%s\0".as_slice()); |
| let res = libc::pthread_setname_np( |
| libc::pthread_self(), |
| cname.as_ptr(), |
| name.as_ptr() as *mut libc::c_void, |
| ); |
| debug_assert_eq!(res, 0); |
| } |
| } |
| |
| #[cfg(any(target_os = "solaris", target_os = "illumos"))] |
| pub fn set_name(name: &CStr) { |
| weak! { |
| fn pthread_setname_np( |
| libc::pthread_t, *const libc::c_char |
| ) -> libc::c_int |
| } |
| |
| if let Some(f) = pthread_setname_np.get() { |
| let res = unsafe { f(libc::pthread_self(), name.as_ptr()) }; |
| debug_assert_eq!(res, 0); |
| } |
| } |
| |
| #[cfg(target_os = "fuchsia")] |
| pub fn set_name(name: &CStr) { |
| use self::zircon::*; |
| unsafe { |
| zx_object_set_property( |
| zx_thread_self(), |
| ZX_PROP_NAME, |
| name.as_ptr() as *const libc::c_void, |
| name.to_bytes().len(), |
| ); |
| } |
| } |
| |
| #[cfg(target_os = "haiku")] |
| pub fn set_name(name: &CStr) { |
| unsafe { |
| let thread_self = libc::find_thread(ptr::null_mut()); |
| libc::rename_thread(thread_self, name.as_ptr()); |
| } |
| } |
| |
| #[cfg(any( |
| target_env = "newlib", |
| target_os = "l4re", |
| target_os = "emscripten", |
| target_os = "redox", |
| target_os = "vxworks" |
| ))] |
| pub fn set_name(_name: &CStr) { |
| // Newlib, Emscripten, and VxWorks have no way to set a thread name. |
| } |
| |
| #[cfg(not(target_os = "espidf"))] |
| pub fn sleep(dur: Duration) { |
| let mut secs = dur.as_secs(); |
| let mut nsecs = dur.subsec_nanos() as _; |
| |
| // If we're awoken with a signal then the return value will be -1 and |
| // nanosleep will fill in `ts` with the remaining time. |
| unsafe { |
| while secs > 0 || nsecs > 0 { |
| let mut ts = libc::timespec { |
| tv_sec: cmp::min(libc::time_t::MAX as u64, secs) as libc::time_t, |
| tv_nsec: nsecs, |
| }; |
| secs -= ts.tv_sec as u64; |
| let ts_ptr = &mut ts as *mut _; |
| if libc::nanosleep(ts_ptr, ts_ptr) == -1 { |
| assert_eq!(os::errno(), libc::EINTR); |
| secs += ts.tv_sec as u64; |
| nsecs = ts.tv_nsec; |
| } else { |
| nsecs = 0; |
| } |
| } |
| } |
| } |
| |
| #[cfg(target_os = "espidf")] |
| pub fn sleep(dur: Duration) { |
| let mut micros = dur.as_micros(); |
| unsafe { |
| while micros > 0 { |
| let st = if micros > u32::MAX as u128 { u32::MAX } else { micros as u32 }; |
| libc::usleep(st); |
| |
| micros -= st as u128; |
| } |
| } |
| } |
| |
| pub fn join(self) { |
| unsafe { |
| let ret = libc::pthread_join(self.id, ptr::null_mut()); |
| mem::forget(self); |
| assert!(ret == 0, "failed to join thread: {}", io::Error::from_raw_os_error(ret)); |
| } |
| } |
| |
| pub fn id(&self) -> libc::pthread_t { |
| self.id |
| } |
| |
| pub fn into_id(self) -> libc::pthread_t { |
| let id = self.id; |
| mem::forget(self); |
| id |
| } |
| } |
| |
| impl Drop for Thread { |
| fn drop(&mut self) { |
| let ret = unsafe { libc::pthread_detach(self.id) }; |
| debug_assert_eq!(ret, 0); |
| } |
| } |
| |
| #[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( |
| target_os = "android", |
| target_os = "emscripten", |
| target_os = "fuchsia", |
| target_os = "ios", |
| target_os = "linux", |
| target_os = "macos", |
| target_os = "solaris", |
| target_os = "illumos", |
| ))] { |
| #[cfg(any(target_os = "android", target_os = "linux"))] |
| { |
| let quota = cgroups::quota().max(1); |
| let mut set: libc::cpu_set_t = unsafe { mem::zeroed() }; |
| unsafe { |
| if libc::sched_getaffinity(0, mem::size_of::<libc::cpu_set_t>(), &mut set) == 0 { |
| let count = libc::CPU_COUNT(&set) as usize; |
| let count = count.min(quota); |
| // SAFETY: affinity mask can't be empty and the quota gets clamped to a minimum of 1 |
| return Ok(NonZeroUsize::new_unchecked(count)); |
| } |
| } |
| } |
| match unsafe { libc::sysconf(libc::_SC_NPROCESSORS_ONLN) } { |
| -1 => Err(io::Error::last_os_error()), |
| 0 => Err(io::const_io_error!(io::ErrorKind::NotFound, "The number of hardware threads is not known for the target platform")), |
| cpus => Ok(unsafe { NonZeroUsize::new_unchecked(cpus as usize) }), |
| } |
| } else if #[cfg(any(target_os = "freebsd", target_os = "dragonfly", target_os = "netbsd"))] { |
| use crate::ptr; |
| |
| let mut cpus: libc::c_uint = 0; |
| let mut cpus_size = crate::mem::size_of_val(&cpus); |
| |
| unsafe { |
| cpus = libc::sysconf(libc::_SC_NPROCESSORS_ONLN) as libc::c_uint; |
| } |
| |
| // Fallback approach in case of errors or no hardware threads. |
| if cpus < 1 { |
| let mut mib = [libc::CTL_HW, libc::HW_NCPU, 0, 0]; |
| let res = unsafe { |
| libc::sysctl( |
| mib.as_mut_ptr(), |
| 2, |
| &mut cpus as *mut _ as *mut _, |
| &mut cpus_size as *mut _ as *mut _, |
| ptr::null_mut(), |
| 0, |
| ) |
| }; |
| |
| // Handle errors if any. |
| if res == -1 { |
| return Err(io::Error::last_os_error()); |
| } else if cpus == 0 { |
| return Err(io::const_io_error!(io::ErrorKind::NotFound, "The number of hardware threads is not known for the target platform")); |
| } |
| } |
| Ok(unsafe { NonZeroUsize::new_unchecked(cpus as usize) }) |
| } else if #[cfg(target_os = "openbsd")] { |
| use crate::ptr; |
| |
| let mut cpus: libc::c_uint = 0; |
| let mut cpus_size = crate::mem::size_of_val(&cpus); |
| let mut mib = [libc::CTL_HW, libc::HW_NCPU, 0, 0]; |
| |
| let res = unsafe { |
| libc::sysctl( |
| mib.as_mut_ptr(), |
| 2, |
| &mut cpus as *mut _ as *mut _, |
| &mut cpus_size as *mut _ as *mut _, |
| ptr::null_mut(), |
| 0, |
| ) |
| }; |
| |
| // Handle errors if any. |
| if res == -1 { |
| return Err(io::Error::last_os_error()); |
| } else if cpus == 0 { |
| return Err(io::const_io_error!(io::ErrorKind::NotFound, "The number of hardware threads is not known for the target platform")); |
| } |
| |
| Ok(unsafe { NonZeroUsize::new_unchecked(cpus as usize) }) |
| } else if #[cfg(target_os = "haiku")] { |
| // system_info cpu_count field gets the static data set at boot time with `smp_set_num_cpus` |
| // `get_system_info` calls then `smp_get_num_cpus` |
| unsafe { |
| let mut sinfo: libc::system_info = crate::mem::zeroed(); |
| let res = libc::get_system_info(&mut sinfo); |
| |
| if res != libc::B_OK { |
| return Err(io::const_io_error!(io::ErrorKind::NotFound, "The number of hardware threads is not known for the target platform")); |
| } |
| |
| Ok(NonZeroUsize::new_unchecked(sinfo.cpu_count as usize)) |
| } |
| } else { |
| // FIXME: implement on vxWorks, Redox, l4re |
| Err(io::const_io_error!(io::ErrorKind::Unsupported, "Getting the number of hardware threads is not supported on the target platform")) |
| } |
| } |
| } |
| |
| #[cfg(any(target_os = "android", target_os = "linux"))] |
| mod cgroups { |
| //! Currently not covered |
| //! * cgroup v2 in non-standard mountpoints |
| //! * paths containing control characters or spaces, since those would be escaped in procfs |
| //! output and we don't unescape |
| use crate::borrow::Cow; |
| use crate::ffi::OsString; |
| use crate::fs::{try_exists, File}; |
| use crate::io::Read; |
| use crate::io::{BufRead, BufReader}; |
| use crate::os::unix::ffi::OsStringExt; |
| use crate::path::Path; |
| use crate::path::PathBuf; |
| use crate::str::from_utf8; |
| |
| #[derive(PartialEq)] |
| enum Cgroup { |
| V1, |
| V2, |
| } |
| |
| /// Returns cgroup CPU quota in core-equivalents, rounded down or usize::MAX if the quota cannot |
| /// be determined or is not set. |
| pub(super) fn quota() -> usize { |
| let mut quota = usize::MAX; |
| if cfg!(miri) { |
| // Attempting to open a file fails under default flags due to isolation. |
| // And Miri does not have parallelism anyway. |
| return quota; |
| } |
| |
| let _: Option<()> = try { |
| let mut buf = Vec::with_capacity(128); |
| // find our place in the cgroup hierarchy |
| File::open("/proc/self/cgroup").ok()?.read_to_end(&mut buf).ok()?; |
| let (cgroup_path, version) = |
| buf.split(|&c| c == b'\n').fold(None, |previous, line| { |
| let mut fields = line.splitn(3, |&c| c == b':'); |
| // 2nd field is a list of controllers for v1 or empty for v2 |
| let version = match fields.nth(1) { |
| Some(b"") => Cgroup::V2, |
| Some(controllers) |
| if from_utf8(controllers) |
| .is_ok_and(|c| c.split(',').any(|c| c == "cpu")) => |
| { |
| Cgroup::V1 |
| } |
| _ => return previous, |
| }; |
| |
| // already-found v1 trumps v2 since it explicitly specifies its controllers |
| if previous.is_some() && version == Cgroup::V2 { |
| return previous; |
| } |
| |
| let path = fields.last()?; |
| // skip leading slash |
| Some((path[1..].to_owned(), version)) |
| })?; |
| let cgroup_path = PathBuf::from(OsString::from_vec(cgroup_path)); |
| |
| quota = match version { |
| Cgroup::V1 => quota_v1(cgroup_path), |
| Cgroup::V2 => quota_v2(cgroup_path), |
| }; |
| }; |
| |
| quota |
| } |
| |
| fn quota_v2(group_path: PathBuf) -> usize { |
| let mut quota = usize::MAX; |
| |
| let mut path = PathBuf::with_capacity(128); |
| let mut read_buf = String::with_capacity(20); |
| |
| // standard mount location defined in file-hierarchy(7) manpage |
| let cgroup_mount = "/sys/fs/cgroup"; |
| |
| path.push(cgroup_mount); |
| path.push(&group_path); |
| |
| path.push("cgroup.controllers"); |
| |
| // skip if we're not looking at cgroup2 |
| if matches!(try_exists(&path), Err(_) | Ok(false)) { |
| return usize::MAX; |
| }; |
| |
| path.pop(); |
| |
| let _: Option<()> = try { |
| while path.starts_with(cgroup_mount) { |
| path.push("cpu.max"); |
| |
| read_buf.clear(); |
| |
| if File::open(&path).and_then(|mut f| f.read_to_string(&mut read_buf)).is_ok() { |
| let raw_quota = read_buf.lines().next()?; |
| let mut raw_quota = raw_quota.split(' '); |
| let limit = raw_quota.next()?; |
| let period = raw_quota.next()?; |
| match (limit.parse::<usize>(), period.parse::<usize>()) { |
| (Ok(limit), Ok(period)) => { |
| quota = quota.min(limit / period); |
| } |
| _ => {} |
| } |
| } |
| |
| path.pop(); // pop filename |
| path.pop(); // pop dir |
| } |
| }; |
| |
| quota |
| } |
| |
| fn quota_v1(group_path: PathBuf) -> usize { |
| let mut quota = usize::MAX; |
| let mut path = PathBuf::with_capacity(128); |
| let mut read_buf = String::with_capacity(20); |
| |
| // Hardcode commonly used locations mentioned in the cgroups(7) manpage |
| // if that doesn't work scan mountinfo and adjust `group_path` for bind-mounts |
| let mounts: &[fn(&Path) -> Option<(_, &Path)>] = &[ |
| |p| Some((Cow::Borrowed("/sys/fs/cgroup/cpu"), p)), |
| |p| Some((Cow::Borrowed("/sys/fs/cgroup/cpu,cpuacct"), p)), |
| // this can be expensive on systems with tons of mountpoints |
| // but we only get to this point when /proc/self/cgroups explicitly indicated |
| // this process belongs to a cpu-controller cgroup v1 and the defaults didn't work |
| find_mountpoint, |
| ]; |
| |
| for mount in mounts { |
| let Some((mount, group_path)) = mount(&group_path) else { continue }; |
| |
| path.clear(); |
| path.push(mount.as_ref()); |
| path.push(&group_path); |
| |
| // skip if we guessed the mount incorrectly |
| if matches!(try_exists(&path), Err(_) | Ok(false)) { |
| continue; |
| } |
| |
| while path.starts_with(mount.as_ref()) { |
| let mut parse_file = |name| { |
| path.push(name); |
| read_buf.clear(); |
| |
| let f = File::open(&path); |
| path.pop(); // restore buffer before any early returns |
| f.ok()?.read_to_string(&mut read_buf).ok()?; |
| let parsed = read_buf.trim().parse::<usize>().ok()?; |
| |
| Some(parsed) |
| }; |
| |
| let limit = parse_file("cpu.cfs_quota_us"); |
| let period = parse_file("cpu.cfs_period_us"); |
| |
| match (limit, period) { |
| (Some(limit), Some(period)) => quota = quota.min(limit / period), |
| _ => {} |
| } |
| |
| path.pop(); |
| } |
| |
| // we passed the try_exists above so we should have traversed the correct hierarchy |
| // when reaching this line |
| break; |
| } |
| |
| quota |
| } |
| |
| /// Scan mountinfo for cgroup v1 mountpoint with a cpu controller |
| /// |
| /// If the cgroupfs is a bind mount then `group_path` is adjusted to skip |
| /// over the already-included prefix |
| fn find_mountpoint(group_path: &Path) -> Option<(Cow<'static, str>, &Path)> { |
| let mut reader = BufReader::new(File::open("/proc/self/mountinfo").ok()?); |
| let mut line = String::with_capacity(256); |
| loop { |
| line.clear(); |
| if reader.read_line(&mut line).ok()? == 0 { |
| break; |
| } |
| |
| let line = line.trim(); |
| let mut items = line.split(' '); |
| |
| let sub_path = items.nth(3)?; |
| let mount_point = items.next()?; |
| let mount_opts = items.next_back()?; |
| let filesystem_type = items.nth_back(1)?; |
| |
| if filesystem_type != "cgroup" || !mount_opts.split(',').any(|opt| opt == "cpu") { |
| // not a cgroup / not a cpu-controller |
| continue; |
| } |
| |
| let sub_path = Path::new(sub_path).strip_prefix("/").ok()?; |
| |
| if !group_path.starts_with(sub_path) { |
| // this is a bind-mount and the bound subdirectory |
| // does not contain the cgroup this process belongs to |
| continue; |
| } |
| |
| let trimmed_group_path = group_path.strip_prefix(sub_path).ok()?; |
| |
| return Some((Cow::Owned(mount_point.to_owned()), trimmed_group_path)); |
| } |
| |
| None |
| } |
| } |
| |
| #[cfg(all( |
| not(target_os = "linux"), |
| not(target_os = "freebsd"), |
| not(target_os = "macos"), |
| not(target_os = "netbsd"), |
| not(target_os = "openbsd"), |
| not(target_os = "solaris") |
| ))] |
| #[cfg_attr(test, allow(dead_code))] |
| pub mod guard { |
| use crate::ops::Range; |
| pub type Guard = Range<usize>; |
| pub unsafe fn current() -> Option<Guard> { |
| None |
| } |
| pub unsafe fn init() -> Option<Guard> { |
| None |
| } |
| } |
| |
| #[cfg(any( |
| target_os = "linux", |
| target_os = "freebsd", |
| target_os = "macos", |
| target_os = "netbsd", |
| target_os = "openbsd", |
| target_os = "solaris" |
| ))] |
| #[cfg_attr(test, allow(dead_code))] |
| pub mod guard { |
| use libc::{mmap, mprotect}; |
| use libc::{MAP_ANON, MAP_FAILED, MAP_FIXED, MAP_PRIVATE, PROT_NONE, PROT_READ, PROT_WRITE}; |
| |
| use crate::io; |
| use crate::ops::Range; |
| use crate::sync::atomic::{AtomicUsize, Ordering}; |
| use crate::sys::os; |
| |
| // This is initialized in init() and only read from after |
| static PAGE_SIZE: AtomicUsize = AtomicUsize::new(0); |
| |
| pub type Guard = Range<usize>; |
| |
| #[cfg(target_os = "solaris")] |
| unsafe fn get_stack_start() -> Option<*mut libc::c_void> { |
| let mut current_stack: libc::stack_t = crate::mem::zeroed(); |
| assert_eq!(libc::stack_getbounds(&mut current_stack), 0); |
| Some(current_stack.ss_sp) |
| } |
| |
| #[cfg(target_os = "macos")] |
| unsafe fn get_stack_start() -> Option<*mut libc::c_void> { |
| let th = libc::pthread_self(); |
| let stackptr = libc::pthread_get_stackaddr_np(th); |
| Some(stackptr.map_addr(|addr| addr - libc::pthread_get_stacksize_np(th))) |
| } |
| |
| #[cfg(target_os = "openbsd")] |
| unsafe fn get_stack_start() -> Option<*mut libc::c_void> { |
| let mut current_stack: libc::stack_t = crate::mem::zeroed(); |
| assert_eq!(libc::pthread_stackseg_np(libc::pthread_self(), &mut current_stack), 0); |
| |
| let stack_ptr = current_stack.ss_sp; |
| let stackaddr = if libc::pthread_main_np() == 1 { |
| // main thread |
| stack_ptr.addr() - current_stack.ss_size + PAGE_SIZE.load(Ordering::Relaxed) |
| } else { |
| // new thread |
| stack_ptr.addr() - current_stack.ss_size |
| }; |
| Some(stack_ptr.with_addr(stackaddr)) |
| } |
| |
| #[cfg(any( |
| target_os = "android", |
| target_os = "freebsd", |
| target_os = "linux", |
| target_os = "netbsd", |
| target_os = "l4re" |
| ))] |
| unsafe fn get_stack_start() -> Option<*mut libc::c_void> { |
| let mut ret = None; |
| let mut attr: libc::pthread_attr_t = crate::mem::zeroed(); |
| #[cfg(target_os = "freebsd")] |
| assert_eq!(libc::pthread_attr_init(&mut attr), 0); |
| #[cfg(target_os = "freebsd")] |
| let e = libc::pthread_attr_get_np(libc::pthread_self(), &mut attr); |
| #[cfg(not(target_os = "freebsd"))] |
| let e = libc::pthread_getattr_np(libc::pthread_self(), &mut attr); |
| if e == 0 { |
| let mut stackaddr = crate::ptr::null_mut(); |
| let mut stacksize = 0; |
| assert_eq!(libc::pthread_attr_getstack(&attr, &mut stackaddr, &mut stacksize), 0); |
| ret = Some(stackaddr); |
| } |
| if e == 0 || cfg!(target_os = "freebsd") { |
| assert_eq!(libc::pthread_attr_destroy(&mut attr), 0); |
| } |
| ret |
| } |
| |
| // Precondition: PAGE_SIZE is initialized. |
| unsafe fn get_stack_start_aligned() -> Option<*mut libc::c_void> { |
| let page_size = PAGE_SIZE.load(Ordering::Relaxed); |
| assert!(page_size != 0); |
| let stackptr = get_stack_start()?; |
| let stackaddr = stackptr.addr(); |
| |
| // Ensure stackaddr is page aligned! A parent process might |
| // have reset RLIMIT_STACK to be non-page aligned. The |
| // pthread_attr_getstack() reports the usable stack area |
| // stackaddr < stackaddr + stacksize, so if stackaddr is not |
| // page-aligned, calculate the fix such that stackaddr < |
| // new_page_aligned_stackaddr < stackaddr + stacksize |
| let remainder = stackaddr % page_size; |
| Some(if remainder == 0 { |
| stackptr |
| } else { |
| stackptr.with_addr(stackaddr + page_size - remainder) |
| }) |
| } |
| |
| pub unsafe fn init() -> Option<Guard> { |
| let page_size = os::page_size(); |
| PAGE_SIZE.store(page_size, Ordering::Relaxed); |
| |
| if cfg!(all(target_os = "linux", not(target_env = "musl"))) { |
| // Linux doesn't allocate the whole stack right away, and |
| // the kernel has its own stack-guard mechanism to fault |
| // when growing too close to an existing mapping. If we map |
| // our own guard, then the kernel starts enforcing a rather |
| // large gap above that, rendering much of the possible |
| // stack space useless. See #43052. |
| // |
| // Instead, we'll just note where we expect rlimit to start |
| // faulting, so our handler can report "stack overflow", and |
| // trust that the kernel's own stack guard will work. |
| let stackptr = get_stack_start_aligned()?; |
| let stackaddr = stackptr.addr(); |
| Some(stackaddr - page_size..stackaddr) |
| } else if cfg!(all(target_os = "linux", target_env = "musl")) { |
| // For the main thread, the musl's pthread_attr_getstack |
| // returns the current stack size, rather than maximum size |
| // it can eventually grow to. It cannot be used to determine |
| // the position of kernel's stack guard. |
| None |
| } else if cfg!(target_os = "freebsd") { |
| // FreeBSD's stack autogrows, and optionally includes a guard page |
| // at the bottom. If we try to remap the bottom of the stack |
| // ourselves, FreeBSD's guard page moves upwards. So we'll just use |
| // the builtin guard page. |
| let stackptr = get_stack_start_aligned()?; |
| let guardaddr = stackptr.addr(); |
| // Technically the number of guard pages is tunable and controlled |
| // by the security.bsd.stack_guard_page sysctl, but there are |
| // few reasons to change it from the default. The default value has |
| // been 1 ever since FreeBSD 11.1 and 10.4. |
| const GUARD_PAGES: usize = 1; |
| let guard = guardaddr..guardaddr + GUARD_PAGES * page_size; |
| Some(guard) |
| } else if cfg!(target_os = "openbsd") { |
| // OpenBSD stack already includes a guard page, and stack is |
| // immutable. |
| // |
| // We'll just note where we expect rlimit to start |
| // faulting, so our handler can report "stack overflow", and |
| // trust that the kernel's own stack guard will work. |
| let stackptr = get_stack_start_aligned()?; |
| let stackaddr = stackptr.addr(); |
| Some(stackaddr - page_size..stackaddr) |
| } else { |
| // Reallocate the last page of the stack. |
| // This ensures SIGBUS will be raised on |
| // stack overflow. |
| // Systems which enforce strict PAX MPROTECT do not allow |
| // to mprotect() a mapping with less restrictive permissions |
| // than the initial mmap() used, so we mmap() here with |
| // read/write permissions and only then mprotect() it to |
| // no permissions at all. See issue #50313. |
| let stackptr = get_stack_start_aligned()?; |
| let result = mmap( |
| stackptr, |
| page_size, |
| PROT_READ | PROT_WRITE, |
| MAP_PRIVATE | MAP_ANON | MAP_FIXED, |
| -1, |
| 0, |
| ); |
| if result != stackptr || result == MAP_FAILED { |
| panic!("failed to allocate a guard page: {}", io::Error::last_os_error()); |
| } |
| |
| let result = mprotect(stackptr, page_size, PROT_NONE); |
| if result != 0 { |
| panic!("failed to protect the guard page: {}", io::Error::last_os_error()); |
| } |
| |
| let guardaddr = stackptr.addr(); |
| |
| Some(guardaddr..guardaddr + page_size) |
| } |
| } |
| |
| #[cfg(any(target_os = "macos", target_os = "openbsd", target_os = "solaris"))] |
| pub unsafe fn current() -> Option<Guard> { |
| let stackptr = get_stack_start()?; |
| let stackaddr = stackptr.addr(); |
| Some(stackaddr - PAGE_SIZE.load(Ordering::Relaxed)..stackaddr) |
| } |
| |
| #[cfg(any( |
| target_os = "android", |
| target_os = "freebsd", |
| target_os = "linux", |
| target_os = "netbsd", |
| target_os = "l4re" |
| ))] |
| pub unsafe fn current() -> Option<Guard> { |
| let mut ret = None; |
| let mut attr: libc::pthread_attr_t = crate::mem::zeroed(); |
| #[cfg(target_os = "freebsd")] |
| assert_eq!(libc::pthread_attr_init(&mut attr), 0); |
| #[cfg(target_os = "freebsd")] |
| let e = libc::pthread_attr_get_np(libc::pthread_self(), &mut attr); |
| #[cfg(not(target_os = "freebsd"))] |
| let e = libc::pthread_getattr_np(libc::pthread_self(), &mut attr); |
| if e == 0 { |
| let mut guardsize = 0; |
| assert_eq!(libc::pthread_attr_getguardsize(&attr, &mut guardsize), 0); |
| if guardsize == 0 { |
| if cfg!(all(target_os = "linux", target_env = "musl")) { |
| // musl versions before 1.1.19 always reported guard |
| // size obtained from pthread_attr_get_np as zero. |
| // Use page size as a fallback. |
| guardsize = PAGE_SIZE.load(Ordering::Relaxed); |
| } else { |
| panic!("there is no guard page"); |
| } |
| } |
| let mut stackptr = crate::ptr::null_mut::<libc::c_void>(); |
| let mut size = 0; |
| assert_eq!(libc::pthread_attr_getstack(&attr, &mut stackptr, &mut size), 0); |
| |
| let stackaddr = stackptr.addr(); |
| ret = if cfg!(any(target_os = "freebsd", target_os = "netbsd")) { |
| Some(stackaddr - guardsize..stackaddr) |
| } else if cfg!(all(target_os = "linux", target_env = "musl")) { |
| Some(stackaddr - guardsize..stackaddr) |
| } else if cfg!(all(target_os = "linux", any(target_env = "gnu", target_env = "uclibc"))) |
| { |
| // glibc used to include the guard area within the stack, as noted in the BUGS |
| // section of `man pthread_attr_getguardsize`. This has been corrected starting |
| // with glibc 2.27, and in some distro backports, so the guard is now placed at the |
| // end (below) the stack. There's no easy way for us to know which we have at |
| // runtime, so we'll just match any fault in the range right above or below the |
| // stack base to call that fault a stack overflow. |
| Some(stackaddr - guardsize..stackaddr + guardsize) |
| } else { |
| Some(stackaddr..stackaddr + guardsize) |
| }; |
| } |
| if e == 0 || cfg!(target_os = "freebsd") { |
| assert_eq!(libc::pthread_attr_destroy(&mut attr), 0); |
| } |
| ret |
| } |
| } |
| |
| // glibc >= 2.15 has a __pthread_get_minstack() function that returns |
| // PTHREAD_STACK_MIN plus bytes needed for thread-local storage. |
| // We need that information to avoid blowing up when a small stack |
| // is created in an application with big thread-local storage requirements. |
| // See #6233 for rationale and details. |
| #[cfg(all(target_os = "linux", target_env = "gnu"))] |
| fn min_stack_size(attr: *const libc::pthread_attr_t) -> usize { |
| // We use dlsym to avoid an ELF version dependency on GLIBC_PRIVATE. (#23628) |
| // We shouldn't really be using such an internal symbol, but there's currently |
| // no other way to account for the TLS size. |
| dlsym!(fn __pthread_get_minstack(*const libc::pthread_attr_t) -> libc::size_t); |
| |
| match __pthread_get_minstack.get() { |
| None => libc::PTHREAD_STACK_MIN, |
| Some(f) => unsafe { f(attr) }, |
| } |
| } |
| |
| // No point in looking up __pthread_get_minstack() on non-glibc platforms. |
| #[cfg(all(not(all(target_os = "linux", target_env = "gnu")), not(target_os = "netbsd")))] |
| fn min_stack_size(_: *const libc::pthread_attr_t) -> usize { |
| libc::PTHREAD_STACK_MIN |
| } |
| |
| #[cfg(target_os = "netbsd")] |
| fn min_stack_size(_: *const libc::pthread_attr_t) -> usize { |
| 2048 // just a guess |
| } |
