not(target_os = "solaris")))]
#[cfg_attr(test, allow(dead_code))]
pub mod guard {
- pub unsafe fn current() -> Option<usize> { None }
- pub unsafe fn init() -> Option<usize> { None }
+ use ops::Range;
+ pub type Guard = Range<usize>;
+ pub unsafe fn current() -> Option<Guard> { None }
+ pub unsafe fn init() -> Option<Guard> { None }
}
use libc;
use libc::mmap;
use libc::{PROT_NONE, MAP_PRIVATE, MAP_ANON, MAP_FAILED, MAP_FIXED};
+ use ops::Range;
use sys::os;
- #[cfg(any(target_os = "macos",
- target_os = "bitrig",
- target_os = "openbsd",
- target_os = "solaris"))]
+ // 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 = ::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> {
- current().map(|s| s as *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 = ::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",
ret
}
- pub unsafe fn init() -> Option<usize> {
- let psize = os::page_size();
+ pub unsafe fn init() -> Option<Guard> {
+ PAGE_SIZE = os::page_size();
+
let mut stackaddr = get_stack_start()?;
// Ensure stackaddr is page aligned! A parent process might
// 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) % psize;
+ let remainder = (stackaddr as usize) % PAGE_SIZE;
if remainder != 0 {
- stackaddr = ((stackaddr as usize) + psize - remainder)
+ stackaddr = ((stackaddr as usize) + PAGE_SIZE - remainder)
as *mut libc::c_void;
}
// 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.
- Some(stackaddr as usize)
+ 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.
- let result = mmap(stackaddr, psize, PROT_NONE,
+ let result = mmap(stackaddr, PAGE_SIZE, PROT_NONE,
MAP_PRIVATE | MAP_ANON | MAP_FIXED, -1, 0);
if result != stackaddr || result == MAP_FAILED {
panic!("failed to allocate a guard page");
}
+ let guardaddr = stackaddr as usize;
let offset = if cfg!(target_os = "freebsd") {
2
} else {
1
};
- Some(stackaddr as usize + offset * psize)
+ Some(guardaddr..guardaddr + offset * PAGE_SIZE)
}
}
- #[cfg(target_os = "solaris")]
- pub unsafe fn current() -> Option<usize> {
- let mut current_stack: libc::stack_t = ::mem::zeroed();
- assert_eq!(libc::stack_getbounds(&mut current_stack), 0);
- Some(current_stack.ss_sp as usize)
- }
-
- #[cfg(target_os = "macos")]
- pub unsafe fn current() -> Option<usize> {
- Some((libc::pthread_get_stackaddr_np(libc::pthread_self()) as usize -
- libc::pthread_get_stacksize_np(libc::pthread_self())))
- }
-
- #[cfg(any(target_os = "openbsd", target_os = "bitrig"))]
- pub unsafe fn current() -> Option<usize> {
- let mut current_stack: libc::stack_t = ::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} * os::page_size();
- Some(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
- })
+ #[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<usize> {
+ pub unsafe fn current() -> Option<Guard> {
let mut ret = None;
let mut attr: libc::pthread_attr_t = ::mem::zeroed();
assert_eq!(libc::pthread_attr_init(&mut attr), 0);
assert_eq!(libc::pthread_attr_getstack(&attr, &mut stackaddr,
&mut size), 0);
+ let stackaddr = stackaddr as usize;
ret = if cfg!(target_os = "freebsd") {
- Some(stackaddr as usize - guardsize)
+ // 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 as usize)
+ 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 as usize + guardsize)
+ Some(stackaddr..stackaddr + guardsize)
};
}
assert_eq!(libc::pthread_attr_destroy(&mut attr), 0);
projects / rustc.git / commitdiff