| use crate::boxed::FnBox; |
| use crate::cmp; |
| use crate::ffi::CStr; |
| use crate::io; |
| use crate::mem; |
| use crate::ptr; |
| use crate::sys::os; |
| use crate::time::Duration; |
| |
| use crate::sys_common::thread::*; |
| |
| #[cfg(not(target_os = "l4re"))] |
| pub const DEFAULT_MIN_STACK_SIZE: usize = 2 * 1024 * 1024; |
| #[cfg(target_os = "l4re")] |
| pub const DEFAULT_MIN_STACK_SIZE: usize = 1024 * 1024; |
| |
| 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 {} |
| |
| // The pthread_attr_setstacksize symbol doesn't exist in the emscripten libc, |
| // so we have to not link to it to satisfy emcc's ERROR_ON_UNDEFINED_SYMBOLS. |
| #[cfg(not(target_os = "emscripten"))] |
| unsafe fn pthread_attr_setstacksize(attr: *mut libc::pthread_attr_t, |
| stack_size: libc::size_t) -> libc::c_int { |
| libc::pthread_attr_setstacksize(attr, stack_size) |
| } |
| |
| #[cfg(target_os = "emscripten")] |
| unsafe fn pthread_attr_setstacksize(_attr: *mut libc::pthread_attr_t, |
| _stack_size: libc::size_t) -> libc::c_int { |
| panic!() |
| } |
| |
| impl Thread { |
| // unsafe: see thread::Builder::spawn_unchecked for safety requirements |
| pub unsafe fn new(stack: usize, p: Box<dyn FnBox()>) |
| -> io::Result<Thread> { |
| let p = 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); |
| |
| let stack_size = cmp::max(stack, min_stack_size(&attr)); |
| |
| match 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 *const _ as *mut _); |
| assert_eq!(libc::pthread_attr_destroy(&mut attr), 0); |
| |
| return if ret != 0 { |
| Err(io::Error::from_raw_os_error(ret)) |
| } else { |
| mem::forget(p); // ownership passed to pthread_create |
| Ok(Thread { id: native }) |
| }; |
| |
| extern fn thread_start(main: *mut libc::c_void) -> *mut libc::c_void { |
| unsafe { start_thread(main as *mut u8); } |
| ptr::null_mut() |
| } |
| } |
| |
| pub fn yield_now() { |
| let ret = unsafe { libc::sched_yield() }; |
| debug_assert_eq!(ret, 0); |
| } |
| |
| #[cfg(any(target_os = "linux", |
| target_os = "android"))] |
| pub fn set_name(name: &CStr) { |
| const PR_SET_NAME: libc::c_int = 15; |
| // pthread wrapper only appeared in glibc 2.12, so we use syscall |
| // directly. |
| unsafe { |
| libc::prctl(PR_SET_NAME, name.as_ptr() as libc::c_ulong, 0, 0, 0); |
| } |
| } |
| |
| #[cfg(any(target_os = "freebsd", |
| target_os = "dragonfly", |
| target_os = "bitrig", |
| 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"))] |
| pub fn set_name(name: &CStr) { |
| unsafe { |
| libc::pthread_setname_np(name.as_ptr()); |
| } |
| } |
| |
| #[cfg(target_os = "netbsd")] |
| pub fn set_name(name: &CStr) { |
| use crate::ffi::CString; |
| let cname = CString::new(&b"%s"[..]).unwrap(); |
| unsafe { |
| libc::pthread_setname_np(libc::pthread_self(), cname.as_ptr(), |
| name.as_ptr() as *mut libc::c_void); |
| } |
| } |
| #[cfg(any(target_env = "newlib", |
| target_os = "solaris", |
| target_os = "haiku", |
| target_os = "l4re", |
| target_os = "emscripten", |
| target_os = "hermit"))] |
| pub fn set_name(_name: &CStr) { |
| // Newlib, Illumos, Haiku, and Emscripten have no way to set a thread name. |
| } |
| #[cfg(target_os = "fuchsia")] |
| pub fn set_name(_name: &CStr) { |
| // FIXME: determine whether Fuchsia has a way to set a thread name. |
| } |
| |
| 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_value() as u64, secs) as libc::time_t, |
| tv_nsec: nsecs, |
| }; |
| secs -= ts.tv_sec as u64; |
| if libc::nanosleep(&ts, &mut ts) == -1 { |
| assert_eq!(os::errno(), libc::EINTR); |
| secs += ts.tv_sec as u64; |
| nsecs = ts.tv_nsec; |
| } else { |
| nsecs = 0; |
| } |
| } |
| } |
| } |
| |
| 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(all(not(all(target_os = "linux", not(target_env = "musl"))), |
| not(target_os = "freebsd"), |
| not(target_os = "macos"), |
| not(target_os = "bitrig"), |
| not(all(target_os = "netbsd", not(target_vendor = "rumprun"))), |
| 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(all(target_os = "linux", not(target_env = "musl")), |
| target_os = "freebsd", |
| target_os = "macos", |
| target_os = "bitrig", |
| all(target_os = "netbsd", not(target_vendor = "rumprun")), |
| target_os = "openbsd", |
| target_os = "solaris"))] |
| #[cfg_attr(test, allow(dead_code))] |
| pub mod guard { |
| use libc::{mmap, mprotect}; |
| use libc::{PROT_NONE, PROT_READ, PROT_WRITE, MAP_PRIVATE, MAP_ANON, MAP_FAILED, MAP_FIXED}; |
| |
| use crate::ops::Range; |
| use crate::sys::os; |
| |
| // This is initialized in init() and only read from after |
| static mut PAGE_SIZE: usize = 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 stackaddr = libc::pthread_get_stackaddr_np(libc::pthread_self()) as usize - |
| libc::pthread_get_stacksize_np(libc::pthread_self()); |
| Some(stackaddr as *mut libc::c_void) |
| } |
| |
| #[cfg(any(target_os = "openbsd", target_os = "bitrig"))] |
| 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 extra = if cfg!(target_os = "bitrig") {3} else {1} * PAGE_SIZE; |
| let stackaddr = if libc::pthread_main_np() == 1 { |
| // main thread |
| current_stack.ss_sp as usize - current_stack.ss_size + extra |
| } else { |
| // new thread |
| current_stack.ss_sp as usize - current_stack.ss_size |
| }; |
| Some(stackaddr as *mut libc::c_void) |
| } |
| |
| #[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(); |
| 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); |
| } |
| 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> { |
| assert!(PAGE_SIZE != 0); |
| let stackaddr = get_stack_start()?; |
| |
| // 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 as usize) % PAGE_SIZE; |
| Some(if remainder == 0 { |
| stackaddr |
| } else { |
| ((stackaddr as usize) + PAGE_SIZE - remainder) as *mut libc::c_void |
| }) |
| } |
| |
| pub unsafe fn init() -> Option<Guard> { |
| PAGE_SIZE = os::page_size(); |
| |
| let stackaddr = get_stack_start_aligned()?; |
| |
| if cfg!(target_os = "linux") { |
| // 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 stackaddr = stackaddr as usize; |
| 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 result = mmap(stackaddr, PAGE_SIZE, PROT_READ | PROT_WRITE, |
| MAP_PRIVATE | MAP_ANON | MAP_FIXED, -1, 0); |
| if result != stackaddr || result == MAP_FAILED { |
| panic!("failed to allocate a guard page"); |
| } |
| |
| let result = mprotect(stackaddr, PAGE_SIZE, PROT_NONE); |
| if result != 0 { |
| panic!("failed to protect the guard page"); |
| } |
| |
| let guardaddr = stackaddr as usize; |
| let offset = if cfg!(target_os = "freebsd") { |
| 2 |
| } else { |
| 1 |
| }; |
| |
| Some(guardaddr..guardaddr + offset * PAGE_SIZE) |
| } |
| } |
| |
| #[cfg(any(target_os = "macos", |
| target_os = "bitrig", |
| target_os = "openbsd", |
| target_os = "solaris"))] |
| pub unsafe fn current() -> Option<Guard> { |
| let stackaddr = get_stack_start()? as usize; |
| Some(stackaddr - PAGE_SIZE..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(); |
| 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 { |
| panic!("there is no guard page"); |
| } |
| let mut stackaddr = crate::ptr::null_mut(); |
| let mut size = 0; |
| assert_eq!(libc::pthread_attr_getstack(&attr, &mut stackaddr, |
| &mut size), 0); |
| |
| let stackaddr = stackaddr as usize; |
| ret = if cfg!(target_os = "freebsd") { |
| // FIXME does freebsd really fault *below* the guard addr? |
| let guardaddr = stackaddr - guardsize; |
| Some(guardaddr - PAGE_SIZE..guardaddr) |
| } else if cfg!(target_os = "netbsd") { |
| Some(stackaddr - guardsize..stackaddr) |
| } else if cfg!(all(target_os = "linux", target_env = "gnu")) { |
| // 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) |
| }; |
| } |
| 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 however many bytes are 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(target_os = "linux")] |
| #[allow(deprecated)] |
| fn min_stack_size(attr: *const libc::pthread_attr_t) -> usize { |
| weak!(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(target_os = "linux"), |
| 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 |
| } |
