src/libstd/sys/unix/thread.rs

   1 // Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use alloc::boxed::FnBox;
  12 use cmp;
  13 use ffi::CStr;
  14 use io;
  15 use libc;
  16 use mem;
  17 use ptr;
  18 use sys::os;
  19 use time::Duration;
  20
  21 use sys_common::thread::*;
  22
  23 pub struct Thread {
  24     id: libc::pthread_t,
  25 }
  26
  27 // Some platforms may have pthread_t as a pointer in which case we still want
  28 // a thread to be Send/Sync
  29 unsafe impl Send for Thread {}
  30 unsafe impl Sync for Thread {}
  31
  32 // The pthread_attr_setstacksize symbol doesn't exist in the emscripten libc,
  33 // so we have to not link to it to satisfy emcc's ERROR_ON_UNDEFINED_SYMBOLS.
  34 #[cfg(not(target_os = "emscripten"))]
  35 unsafe fn pthread_attr_setstacksize(attr: *mut libc::pthread_attr_t,
  36                                     stack_size: libc::size_t) -> libc::c_int {
  37     libc::pthread_attr_setstacksize(attr, stack_size)
  38 }
  39
  40 #[cfg(target_os = "emscripten")]
  41 unsafe fn pthread_attr_setstacksize(_attr: *mut libc::pthread_attr_t,
  42                                     _stack_size: libc::size_t) -> libc::c_int {
  43     panic!()
  44 }
  45
  46 impl Thread {
  47     pub unsafe fn new<'a>(stack: usize, p: Box<FnBox() + 'a>)
  48                           -> io::Result<Thread> {
  49         let p = box p;
  50         let mut native: libc::pthread_t = mem::zeroed();
  51         let mut attr: libc::pthread_attr_t = mem::zeroed();
  52         assert_eq!(libc::pthread_attr_init(&mut attr), 0);
  53
  54         let stack_size = cmp::max(stack, min_stack_size(&attr));
  55         match pthread_attr_setstacksize(&mut attr,
  56                                         stack_size) {
  57             0 => {}
  58             n => {
  59                 assert_eq!(n, libc::EINVAL);
  60                 // EINVAL means |stack_size| is either too small or not a
  61                 // multiple of the system page size.  Because it's definitely
  62                 // >= PTHREAD_STACK_MIN, it must be an alignment issue.
  63                 // Round up to the nearest page and try again.
  64                 let page_size = os::page_size();
  65                 let stack_size = (stack_size + page_size - 1) &
  66                                  (-(page_size as isize - 1) as usize - 1);
  67                 assert_eq!(libc::pthread_attr_setstacksize(&mut attr,
  68                                                            stack_size), 0);
  69             }
  70         };
  71
  72         let ret = libc::pthread_create(&mut native, &attr, thread_start,
  73                                        &*p as *const _ as *mut _);
  74         assert_eq!(libc::pthread_attr_destroy(&mut attr), 0);
  75
  76         return if ret != 0 {
  77             Err(io::Error::from_raw_os_error(ret))
  78         } else {
  79             mem::forget(p); // ownership passed to pthread_create
  80             Ok(Thread { id: native })
  81         };
  82
  83         extern fn thread_start(main: *mut libc::c_void) -> *mut libc::c_void {
  84             unsafe { start_thread(main); }
  85             ptr::null_mut()
  86         }
  87     }
  88
  89     pub fn yield_now() {
  90         let ret = unsafe { libc::sched_yield() };
  91         debug_assert_eq!(ret, 0);
  92     }
  93
  94     #[cfg(any(target_os = "linux",
  95               target_os = "android"))]
  96     pub fn set_name(name: &CStr) {
  97         const PR_SET_NAME: libc::c_int = 15;
  98         // pthread wrapper only appeared in glibc 2.12, so we use syscall
  99         // directly.
 100         unsafe {
 101             libc::prctl(PR_SET_NAME, name.as_ptr() as libc::c_ulong, 0, 0, 0);
 102         }
 103     }
 104
 105     #[cfg(any(target_os = "freebsd",
 106               target_os = "dragonfly",
 107               target_os = "bitrig",
 108               target_os = "openbsd"))]
 109     pub fn set_name(name: &CStr) {
 110         unsafe {
 111             libc::pthread_set_name_np(libc::pthread_self(), name.as_ptr());
 112         }
 113     }
 114
 115     #[cfg(any(target_os = "macos", target_os = "ios"))]
 116     pub fn set_name(name: &CStr) {
 117         unsafe {
 118             libc::pthread_setname_np(name.as_ptr());
 119         }
 120     }
 121
 122     #[cfg(target_os = "netbsd")]
 123     pub fn set_name(name: &CStr) {
 124         use ffi::CString;
 125         let cname = CString::new(&b"%s"[..]).unwrap();
 126         unsafe {
 127             libc::pthread_setname_np(libc::pthread_self(), cname.as_ptr(),
 128                                      name.as_ptr() as *mut libc::c_void);
 129         }
 130     }
 131     #[cfg(any(target_env = "newlib",
 132               target_os = "solaris",
 133               target_os = "haiku",
 134               target_os = "emscripten"))]
 135     pub fn set_name(_name: &CStr) {
 136         // Newlib, Illumos, Haiku, and Emscripten have no way to set a thread name.
 137     }
 138     #[cfg(target_os = "fuchsia")]
 139     pub fn set_name(_name: &CStr) {
 140         // FIXME: determine whether Fuchsia has a way to set a thread name.
 141     }
 142
 143     pub fn sleep(dur: Duration) {
 144         let mut secs = dur.as_secs();
 145         let mut nsecs = dur.subsec_nanos() as libc::c_long;
 146
 147         // If we're awoken with a signal then the return value will be -1 and
 148         // nanosleep will fill in `ts` with the remaining time.
 149         unsafe {
 150             while secs > 0 || nsecs > 0 {
 151                 let mut ts = libc::timespec {
 152                     tv_sec: cmp::min(libc::time_t::max_value() as u64, secs) as libc::time_t,
 153                     tv_nsec: nsecs,
 154                 };
 155                 secs -= ts.tv_sec as u64;
 156                 if libc::nanosleep(&ts, &mut ts) == -1 {
 157                     assert_eq!(os::errno(), libc::EINTR);
 158                     secs += ts.tv_sec as u64;
 159                     nsecs = ts.tv_nsec;
 160                 } else {
 161                     nsecs = 0;
 162                 }
 163             }
 164         }
 165     }
 166
 167     pub fn join(self) {
 168         unsafe {
 169             let ret = libc::pthread_join(self.id, ptr::null_mut());
 170             mem::forget(self);
 171             debug_assert_eq!(ret, 0);
 172         }
 173     }
 174
 175     pub fn id(&self) -> libc::pthread_t { self.id }
 176
 177     pub fn into_id(self) -> libc::pthread_t {
 178         let id = self.id;
 179         mem::forget(self);
 180         id
 181     }
 182 }
 183
 184 impl Drop for Thread {
 185     fn drop(&mut self) {
 186         let ret = unsafe { libc::pthread_detach(self.id) };
 187         debug_assert_eq!(ret, 0);
 188     }
 189 }
 190
 191 #[cfg(all(not(all(target_os = "linux", not(target_env = "musl"))),
 192           not(target_os = "freebsd"),
 193           not(target_os = "macos"),
 194           not(target_os = "bitrig"),
 195           not(all(target_os = "netbsd", not(target_vendor = "rumprun"))),
 196           not(target_os = "openbsd"),
 197           not(target_os = "solaris")))]
 198 #[cfg_attr(test, allow(dead_code))]
 199 pub mod guard {
 200     pub unsafe fn current() -> Option<usize> { None }
 201     pub unsafe fn init() -> Option<usize> { None }
 202 }
 203
 204
 205 #[cfg(any(all(target_os = "linux", not(target_env = "musl")),
 206           target_os = "freebsd",
 207           target_os = "macos",
 208           target_os = "bitrig",
 209           all(target_os = "netbsd", not(target_vendor = "rumprun")),
 210           target_os = "openbsd",
 211           target_os = "solaris"))]
 212 #[cfg_attr(test, allow(dead_code))]
 213 pub mod guard {
 214     use libc;
 215     use libc::mmap;
 216     use libc::{PROT_NONE, MAP_PRIVATE, MAP_ANON, MAP_FAILED, MAP_FIXED};
 217     use sys::os;
 218
 219     #[cfg(any(target_os = "macos",
 220               target_os = "bitrig",
 221               target_os = "openbsd",
 222               target_os = "solaris"))]
 223     unsafe fn get_stack_start() -> Option<*mut libc::c_void> {
 224         current().map(|s| s as *mut libc::c_void)
 225     }
 226
 227     #[cfg(any(target_os = "android", target_os = "freebsd",
 228               target_os = "linux", target_os = "netbsd"))]
 229     unsafe fn get_stack_start() -> Option<*mut libc::c_void> {
 230         let mut ret = None;
 231         let mut attr: libc::pthread_attr_t = ::mem::zeroed();
 232         assert_eq!(libc::pthread_attr_init(&mut attr), 0);
 233         #[cfg(target_os = "freebsd")]
 234             let e = libc::pthread_attr_get_np(libc::pthread_self(), &mut attr);
 235         #[cfg(not(target_os = "freebsd"))]
 236             let e = libc::pthread_getattr_np(libc::pthread_self(), &mut attr);
 237         if e == 0 {
 238             let mut stackaddr = ::ptr::null_mut();
 239             let mut stacksize = 0;
 240             assert_eq!(libc::pthread_attr_getstack(&attr, &mut stackaddr,
 241                                                    &mut stacksize), 0);
 242             ret = Some(stackaddr);
 243         }
 244         assert_eq!(libc::pthread_attr_destroy(&mut attr), 0);
 245         ret
 246     }
 247
 248     pub unsafe fn init() -> Option<usize> {
 249         let psize = os::page_size();
 250         let mut stackaddr = match get_stack_start() {
 251             Some(addr) => addr,
 252             None => return None,
 253         };
 254
 255         // Ensure stackaddr is page aligned! A parent process might
 256         // have reset RLIMIT_STACK to be non-page aligned. The
 257         // pthread_attr_getstack() reports the usable stack area
 258         // stackaddr < stackaddr + stacksize, so if stackaddr is not
 259         // page-aligned, calculate the fix such that stackaddr <
 260         // new_page_aligned_stackaddr < stackaddr + stacksize
 261         let remainder = (stackaddr as usize) % psize;
 262         if remainder != 0 {
 263             stackaddr = ((stackaddr as usize) + psize - remainder)
 264                 as *mut libc::c_void;
 265         }
 266
 267         // Rellocate the last page of the stack.
 268         // This ensures SIGBUS will be raised on
 269         // stack overflow.
 270         let result = mmap(stackaddr, psize, PROT_NONE,
 271                           MAP_PRIVATE | MAP_ANON | MAP_FIXED, -1, 0);
 272
 273         if result != stackaddr || result == MAP_FAILED {
 274             panic!("failed to allocate a guard page");
 275         }
 276
 277         let offset = if cfg!(any(target_os = "linux", target_os = "freebsd")) {
 278             2
 279         } else {
 280             1
 281         };
 282
 283         Some(stackaddr as usize + offset * psize)
 284     }
 285
 286     #[cfg(target_os = "solaris")]
 287     pub unsafe fn current() -> Option<usize> {
 288         let mut current_stack: libc::stack_t = ::mem::zeroed();
 289         assert_eq!(libc::stack_getbounds(&mut current_stack), 0);
 290         Some(current_stack.ss_sp as usize)
 291     }
 292
 293     #[cfg(target_os = "macos")]
 294     pub unsafe fn current() -> Option<usize> {
 295         Some((libc::pthread_get_stackaddr_np(libc::pthread_self()) as usize -
 296               libc::pthread_get_stacksize_np(libc::pthread_self())))
 297     }
 298
 299     #[cfg(any(target_os = "openbsd", target_os = "bitrig"))]
 300     pub unsafe fn current() -> Option<usize> {
 301         let mut current_stack: libc::stack_t = ::mem::zeroed();
 302         assert_eq!(libc::pthread_stackseg_np(libc::pthread_self(),
 303                                              &mut current_stack), 0);
 304
 305         let extra = if cfg!(target_os = "bitrig") {3} else {1} * os::page_size();
 306         Some(if libc::pthread_main_np() == 1 {
 307             // main thread
 308             current_stack.ss_sp as usize - current_stack.ss_size + extra
 309         } else {
 310             // new thread
 311             current_stack.ss_sp as usize - current_stack.ss_size
 312         })
 313     }
 314
 315     #[cfg(any(target_os = "android", target_os = "freebsd",
 316               target_os = "linux", target_os = "netbsd"))]
 317     pub unsafe fn current() -> Option<usize> {
 318         let mut ret = None;
 319         let mut attr: libc::pthread_attr_t = ::mem::zeroed();
 320         assert_eq!(libc::pthread_attr_init(&mut attr), 0);
 321         #[cfg(target_os = "freebsd")]
 322             let e = libc::pthread_attr_get_np(libc::pthread_self(), &mut attr);
 323         #[cfg(not(target_os = "freebsd"))]
 324             let e = libc::pthread_getattr_np(libc::pthread_self(), &mut attr);
 325         if e == 0 {
 326             let mut guardsize = 0;
 327             assert_eq!(libc::pthread_attr_getguardsize(&attr, &mut guardsize), 0);
 328             if guardsize == 0 {
 329                 panic!("there is no guard page");
 330             }
 331             let mut stackaddr = ::ptr::null_mut();
 332             let mut size = 0;
 333             assert_eq!(libc::pthread_attr_getstack(&attr, &mut stackaddr,
 334                                                    &mut size), 0);
 335
 336             ret = if cfg!(target_os = "freebsd") {
 337                 Some(stackaddr as usize - guardsize)
 338             } else if cfg!(target_os = "netbsd") {
 339                 Some(stackaddr as usize)
 340             } else {
 341                 Some(stackaddr as usize + guardsize)
 342             };
 343         }
 344         assert_eq!(libc::pthread_attr_destroy(&mut attr), 0);
 345         ret
 346     }
 347 }
 348
 349 // glibc >= 2.15 has a __pthread_get_minstack() function that returns
 350 // PTHREAD_STACK_MIN plus however many bytes are needed for thread-local
 351 // storage.  We need that information to avoid blowing up when a small stack
 352 // is created in an application with big thread-local storage requirements.
 353 // See #6233 for rationale and details.
 354 #[cfg(target_os = "linux")]
 355 #[allow(deprecated)]
 356 fn min_stack_size(attr: *const libc::pthread_attr_t) -> usize {
 357     weak!(fn __pthread_get_minstack(*const libc::pthread_attr_t) -> libc::size_t);
 358
 359     match __pthread_get_minstack.get() {
 360         None => libc::PTHREAD_STACK_MIN,
 361         Some(f) => unsafe { f(attr) },
 362     }
 363 }
 364
 365 // No point in looking up __pthread_get_minstack() on non-glibc
 366 // platforms.
 367 #[cfg(all(not(target_os = "linux"),
 368           not(target_os = "netbsd")))]
 369 fn min_stack_size(_: *const libc::pthread_attr_t) -> usize {
 370     libc::PTHREAD_STACK_MIN
 371 }
 372
 373 #[cfg(target_os = "netbsd")]
 374 fn min_stack_size(_: *const libc::pthread_attr_t) -> usize {
 375     2048 // just a guess
 376 }