forked from M-Labs/libfringe
separate all the libc interaction out per OS
We're now handling more of this ourselves, and leaving less to libstd. Hopefully, we'll eventually break free of libstd, leaving a highly-focused low-level library that retains all its conveniences in freestanding environments.
This commit is contained in:
parent
46b2a4007b
commit
7e0b126f42
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@ -1,6 +1,6 @@
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#![feature(no_std)]
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#![feature(no_std)]
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#![feature(asm, core)]
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#![feature(asm, core)]
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#![feature(libc, page_size)]
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#![feature(libc)]
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#![no_std]
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#![no_std]
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#[macro_use]
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#[macro_use]
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48
src/os.rs
48
src/os.rs
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@ -1,13 +1,12 @@
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extern crate libc;
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extern crate std;
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extern crate std;
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use self::std::prelude::v1::*;
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use core::prelude::*;
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use self::std::env;
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use self::std::io::Error as IoError;
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use self::std::io::Error as IoError;
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use self::libc::{c_void, size_t};
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use core::ptr;
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use stack;
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use stack;
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use valgrind;
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use valgrind;
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#[cfg(unix)]
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#[path = "os/unix.rs"] mod sys;
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#[allow(raw_pointer_derive)]
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#[allow(raw_pointer_derive)]
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#[derive(Debug)]
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#[derive(Debug)]
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pub struct Stack {
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pub struct Stack {
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@ -34,32 +33,27 @@ impl stack::Stack for Stack {
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fn limit(&self) -> *const u8 {
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fn limit(&self) -> *const u8 {
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unsafe {
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unsafe {
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self.ptr.offset(env::page_size() as isize)
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self.ptr.offset(sys::page_size() as isize)
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}
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}
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}
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}
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}
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}
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impl Stack {
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impl Stack {
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fn new(size: usize) -> Stack {
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fn new(size: usize) -> Stack {
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let page_size = env::page_size();
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let page_size = sys::page_size();
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// round the page size up,
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// round the page size up,
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// using the fact that it is a power of two
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// using the fact that it is a power of two
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let len = (size + page_size - 1) & !(page_size - 1);
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let len = (size + page_size - 1) & !(page_size - 1);
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const STACK_PROT: libc::c_int = libc::PROT_READ | libc::PROT_WRITE;
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const STACK_FLAGS: libc::c_int = libc::MAP_STACK
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| libc::MAP_PRIVATE
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| libc::MAP_ANON;
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let stack = unsafe {
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let stack = unsafe {
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let ptr = libc::mmap(ptr::null_mut(), len as size_t,
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let ptr = match sys::map_stack(size) {
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STACK_PROT, STACK_FLAGS, -1, 0);
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None => {
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panic!("mmap for stack of size {} failed: {:?}",
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if ptr == libc::MAP_FAILED {
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len, IoError::last_os_error())
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panic!("mmap for stack of size {} failed: {:?}",
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}
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len, IoError::last_os_error())
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Some(ptr) => ptr
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}
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};
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let valgrind_id =
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let valgrind_id =
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valgrind::stack_register(ptr as *const _,
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valgrind::stack_register(ptr as *const _,
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@ -68,20 +62,14 @@ impl Stack {
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Stack { ptr: ptr as *mut u8, len: len, valgrind_id: valgrind_id }
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Stack { ptr: ptr as *mut u8, len: len, valgrind_id: valgrind_id }
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};
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};
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stack.protect();
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stack
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}
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fn protect(&self) {
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unsafe {
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unsafe {
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if libc::mprotect(self.ptr as *mut c_void,
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if !sys::protect_stack(stack.ptr) {
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env::page_size() as libc::size_t,
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libc::PROT_NONE) != 0 {
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panic!("mprotect for guard page of stack {:p} failed: {:?}",
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panic!("mprotect for guard page of stack {:p} failed: {:?}",
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self.ptr, IoError::last_os_error());
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stack.ptr, IoError::last_os_error());
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}
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}
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}
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}
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stack
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}
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}
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}
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}
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@ -89,7 +77,7 @@ impl Drop for Stack {
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fn drop(&mut self) {
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fn drop(&mut self) {
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unsafe {
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unsafe {
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valgrind::stack_deregister(self.valgrind_id);
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valgrind::stack_deregister(self.valgrind_id);
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if libc::munmap(self.ptr as *mut c_void, self.len as size_t) != 0 {
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if !sys::unmap_stack(self.ptr, self.len) {
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panic!("munmap for stack {:p} of size {} failed: {:?}",
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panic!("munmap for stack {:p} of size {} failed: {:?}",
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self.ptr, self.len, IoError::last_os_error())
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self.ptr, self.len, IoError::last_os_error())
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}
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}
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@ -0,0 +1,39 @@
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extern crate libc;
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use core::prelude::*;
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pub use self::libc::{c_void, c_int, size_t};
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pub use self::libc::{mmap, mprotect, munmap};
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pub use self::libc::MAP_FAILED;
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use core::ptr;
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pub fn page_size() -> usize {
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unsafe {
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libc::sysconf(libc::_SC_PAGESIZE) as usize
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}
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}
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pub const GUARD_PROT: c_int = libc::PROT_NONE;
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pub const STACK_PROT: c_int = libc::PROT_READ
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| libc::PROT_WRITE;
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pub const STACK_FLAGS: c_int = libc::MAP_STACK
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| libc::MAP_PRIVATE
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| libc::MAP_ANON;
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pub unsafe fn map_stack(len: usize) -> Option<*mut u8> {
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let ptr = mmap(ptr::null_mut(), len as size_t,
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STACK_PROT, STACK_FLAGS, -1, 0);
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if ptr != MAP_FAILED {
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Some(ptr as *mut u8)
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}
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else {
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None
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}
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}
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pub unsafe fn protect_stack(ptr: *mut u8) -> bool {
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mprotect(ptr as *mut c_void, page_size() as size_t, GUARD_PROT) == 0
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}
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pub unsafe fn unmap_stack(ptr: *mut u8, len: usize) -> bool {
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munmap(ptr as *mut c_void, len as size_t) == 0
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}
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