forked from M-Labs/libfringe
99 lines
2.2 KiB
Rust
99 lines
2.2 KiB
Rust
use libc;
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use std::ptr;
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use std::os::{errno, page_size, MemoryMap, MapReadable, MapWritable,
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MapNonStandardFlags};
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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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pub enum Stack {
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Native {
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sp_limit: *const u8
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},
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Managed {
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buf: MemoryMap,
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valgrind_id: libc::c_uint
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}
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}
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extern "C" {
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fn lwut_stack_register(start: *const u8, end: *const u8) -> libc::c_uint;
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fn lwut_stack_deregister(id: libc::c_uint);
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}
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impl Stack {
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pub fn new(size: uint) -> Stack {
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let buf = match MemoryMap::new(size, &[MapReadable, MapWritable,
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MapNonStandardFlags(STACK_FLAGS)]) {
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Ok(map) => map,
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Err(e) => panic!("mmap for stack of size {} failed: {}", size, e)
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};
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if !protect_last_page(&buf) {
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panic!("Could not memory-protect guard page. stack={}, errno={}",
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buf.data(), errno());
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}
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let valgrind_id = unsafe {
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lwut_stack_register(buf.data().offset(buf.len() as int) as *const _,
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buf.data() as *const _)
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};
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let stk = Stack::Managed {
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buf: buf,
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valgrind_id: valgrind_id
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};
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stk
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}
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pub unsafe fn native(limit: *const u8) -> Stack {
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Stack::Native {
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sp_limit: limit
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}
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}
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pub fn top(&self) -> *const u8 {
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unsafe {
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match *self {
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Stack::Native { .. } => ptr::null(),
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Stack::Managed { ref buf, .. } => {
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buf.data().offset(buf.len() as int) as *const _
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}
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}
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}
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}
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pub fn limit(&self) -> *const u8 {
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unsafe {
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match *self {
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Stack::Native { sp_limit, .. } => sp_limit,
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Stack::Managed { ref buf, .. } => {
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buf.data().offset(page_size() as int) as *const _
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}
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}
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}
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}
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}
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fn protect_last_page(stack: &MemoryMap) -> bool {
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unsafe {
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let last_page = stack.data() as *mut libc::c_void;
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libc::mprotect(last_page, page_size() as libc::size_t,
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libc::PROT_NONE) != -1
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}
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}
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impl Drop for Stack {
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fn drop(&mut self) {
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match *self {
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Stack::Native { .. } => {},
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Stack::Managed { valgrind_id, .. } => unsafe {
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lwut_stack_deregister(valgrind_id);
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}
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}
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}
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}
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