4lDO2
353 lines
12 KiB
Rust
353 lines
12 KiB
Rust
//! # Schemes
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//! A scheme is a primitive for handling filesystem syscalls in Redox.
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//! Schemes accept paths from the kernel for `open`, and file descriptors that they generate
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//! are then passed for operations like `close`, `read`, `write`, etc.
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//!
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//! The kernel validates paths and file descriptors before they are passed to schemes,
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//! also stripping the scheme identifier of paths if necessary.
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use alloc::{
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boxed::Box,
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collections::BTreeMap,
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string::ToString,
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sync::Arc,
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vec::Vec,
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};
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use syscall::{CallerCtx, MunmapFlags};
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use core::sync::atomic::AtomicUsize;
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use spin::{Once, RwLock, RwLockReadGuard, RwLockWriteGuard};
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use crate::context::file::FileDescription;
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use crate::context::{memory::AddrSpace, file::FileDescriptor};
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use crate::syscall::error::*;
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use crate::syscall::scheme::Scheme;
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use crate::syscall::usercopy::{UserSliceRo, UserSliceWo};
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#[cfg(all(feature = "acpi", any(target_arch = "x86", target_arch = "x86_64")))]
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use self::acpi::AcpiScheme;
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use self::debug::DebugScheme;
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use self::event::EventScheme;
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use self::irq::IrqScheme;
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use self::itimer::ITimerScheme;
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use self::memory::MemoryScheme;
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use self::pipe::PipeScheme;
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use self::proc::ProcScheme;
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use self::root::RootScheme;
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use self::serio::SerioScheme;
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use self::sys::SysScheme;
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use self::time::TimeScheme;
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use self::user::UserInner;
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/// When compiled with the "acpi" feature - `acpi:` - allows drivers to read a limited set of ACPI tables.
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#[cfg(all(feature = "acpi", any(target_arch = "x86", target_arch = "x86_64")))]
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pub mod acpi;
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/// `debug:` - provides access to serial console
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pub mod debug;
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/// `event:` - allows reading of `Event`s which are registered using `fevent`
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pub mod event;
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/// `irq:` - allows userspace handling of IRQs
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pub mod irq;
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/// `itimer:` - support for getitimer and setitimer
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pub mod itimer;
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/// `memory:` - a scheme for accessing physical memory
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pub mod memory;
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/// `pipe:` - used internally by the kernel to implement `pipe`
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pub mod pipe;
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/// `proc:` - allows tracing processes and reading/writing their memory
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pub mod proc;
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/// `:` - allows the creation of userspace schemes, tightly dependent on `user`
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pub mod root;
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/// `serio:` - provides access to ps/2 devices
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pub mod serio;
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/// `sys:` - system information, such as the context list and scheme list
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pub mod sys;
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/// `time:` - allows reading time, setting timeouts and getting events when they are met
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pub mod time;
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/// A wrapper around userspace schemes, tightly dependent on `root`
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pub mod user;
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/// Limit on number of schemes
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pub const SCHEME_MAX_SCHEMES: usize = 65_536;
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// Unique identifier for a scheme namespace.
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int_like!(SchemeNamespace, AtomicSchemeNamespace, usize, AtomicUsize);
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// Unique identifier for a scheme.
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int_like!(SchemeId, usize);
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// Unique identifier for a file descriptor.
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int_like!(FileHandle, AtomicFileHandle, usize, AtomicUsize);
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pub struct SchemeIter<'a> {
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inner: Option<::alloc::collections::btree_map::Iter<'a, Box<str>, SchemeId>>
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}
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impl<'a> Iterator for SchemeIter<'a> {
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type Item = (&'a Box<str>, &'a SchemeId);
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fn next(&mut self) -> Option<Self::Item> {
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self.inner.as_mut().and_then(|iter| iter.next())
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}
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}
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/// Scheme list type
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pub struct SchemeList {
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map: BTreeMap<SchemeId, Arc<dyn KernelScheme>>,
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names: BTreeMap<SchemeNamespace, BTreeMap<Box<str>, SchemeId>>,
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next_ns: usize,
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next_id: usize
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}
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impl SchemeList {
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/// Create a new scheme list.
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pub fn new() -> Self {
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let mut list = SchemeList {
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map: BTreeMap::new(),
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names: BTreeMap::new(),
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// Scheme namespaces always start at 1. 0 is a reserved namespace, the null namespace
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next_ns: 1,
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next_id: 1
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};
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list.new_null();
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list.new_root();
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list
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}
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/// Initialize the null namespace
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fn new_null(&mut self) {
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let ns = SchemeNamespace(0);
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self.names.insert(ns, BTreeMap::new());
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//TODO: Only memory: is in the null namespace right now. It should be removed when
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//anonymous mmap's are implemented
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self.insert(ns, "memory", |_| Arc::new(MemoryScheme::new())).unwrap();
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self.insert(ns, "thisproc", |_| Arc::new(ProcScheme::restricted())).unwrap();
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self.insert(ns, "pipe", |scheme_id| PipeScheme::new(scheme_id)).unwrap();
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}
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/// Initialize a new namespace
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fn new_ns(&mut self) -> SchemeNamespace {
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let ns = SchemeNamespace(self.next_ns);
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self.next_ns += 1;
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self.names.insert(ns, BTreeMap::new());
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self.insert(ns, "", |scheme_id| Arc::new(RootScheme::new(ns, scheme_id))).unwrap();
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self.insert(ns, "event", |_| Arc::new(EventScheme)).unwrap();
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self.insert(ns, "itimer", |_| Arc::new(ITimerScheme::new())).unwrap();
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self.insert(ns, "memory", |_| Arc::new(MemoryScheme::new())).unwrap();
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self.insert(ns, "pipe", |scheme_id| PipeScheme::new(scheme_id)).unwrap();
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self.insert(ns, "sys", |_| Arc::new(SysScheme::new())).unwrap();
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self.insert(ns, "time", |scheme_id| Arc::new(TimeScheme::new(scheme_id))).unwrap();
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ns
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}
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/// Initialize the root namespace
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fn new_root(&mut self) {
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// Do common namespace initialization
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let ns = self.new_ns();
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// These schemes should only be available on the root
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#[cfg(all(feature = "acpi", any(target_arch = "x86", target_arch = "x86_64")))] {
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self.insert(ns, "kernel/acpi", |scheme_id| Arc::new(AcpiScheme::new(scheme_id))).unwrap();
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}
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self.insert(ns, "debug", |scheme_id| Arc::new(DebugScheme::new(scheme_id))).unwrap();
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self.insert(ns, "irq", |scheme_id| Arc::new(IrqScheme::new(scheme_id))).unwrap();
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self.insert(ns, "proc", |scheme_id| Arc::new(ProcScheme::new(scheme_id))).unwrap();
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self.insert(ns, "thisproc", |_| Arc::new(ProcScheme::restricted())).unwrap();
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self.insert(ns, "serio", |scheme_id| Arc::new(SerioScheme::new(scheme_id))).unwrap();
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}
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pub fn make_ns(&mut self, from: SchemeNamespace, names: impl IntoIterator<Item = Box<str>>) -> Result<SchemeNamespace> {
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// Create an empty namespace
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let to = self.new_ns();
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// Copy requested scheme IDs
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for name in names {
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let Some((id, _scheme)) = self.get_name(from, &name) else {
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return Err(Error::new(ENODEV));
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};
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if let Some(ref mut names) = self.names.get_mut(&to) {
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assert!(names.insert(name.to_string().into_boxed_str(), id).is_none());
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} else {
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panic!("scheme namespace not found");
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}
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}
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Ok(to)
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}
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pub fn iter(&self) -> ::alloc::collections::btree_map::Iter<SchemeId, Arc<dyn KernelScheme>> {
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self.map.iter()
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}
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pub fn iter_name(&self, ns: SchemeNamespace) -> SchemeIter {
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SchemeIter {
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inner: self.names.get(&ns).map(|names| names.iter())
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}
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}
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/// Get the nth scheme.
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pub fn get(&self, id: SchemeId) -> Option<&Arc<dyn KernelScheme>> {
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self.map.get(&id)
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}
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pub fn get_name(&self, ns: SchemeNamespace, name: &str) -> Option<(SchemeId, &Arc<dyn KernelScheme>)> {
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if let Some(names) = self.names.get(&ns) {
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if let Some(&id) = names.get(name) {
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return self.get(id).map(|scheme| (id, scheme));
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}
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}
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None
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}
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/// Create a new scheme.
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pub fn insert(&mut self, ns: SchemeNamespace, name: &str, scheme_fn: impl FnOnce(SchemeId) -> Arc<dyn KernelScheme>) -> Result<SchemeId> {
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self.insert_and_pass(ns, name, |id| (scheme_fn(id), ())).map(|(id, ())| id)
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}
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pub fn insert_and_pass<T>(&mut self, ns: SchemeNamespace, name: &str, scheme_fn: impl FnOnce(SchemeId) -> (Arc<dyn KernelScheme>, T)) -> Result<(SchemeId, T)> {
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if let Some(names) = self.names.get(&ns) {
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if names.contains_key(name) {
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return Err(Error::new(EEXIST));
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}
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}
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if self.next_id >= SCHEME_MAX_SCHEMES {
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self.next_id = 1;
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}
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while self.map.contains_key(&SchemeId(self.next_id)) {
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self.next_id += 1;
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}
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/* Allow scheme list to grow if required
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if self.next_id >= SCHEME_MAX_SCHEMES {
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return Err(Error::new(EAGAIN));
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}
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*/
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let id = SchemeId(self.next_id);
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self.next_id += 1;
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let (new_scheme, t) = scheme_fn(id);
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assert!(self.map.insert(id, new_scheme).is_none());
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if let Some(ref mut names) = self.names.get_mut(&ns) {
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assert!(names.insert(name.to_string().into_boxed_str(), id).is_none());
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} else {
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// Nonexistent namespace, posssibly null namespace
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return Err(Error::new(ENODEV));
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}
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Ok((id, t))
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}
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/// Remove a scheme
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pub fn remove(&mut self, id: SchemeId) {
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assert!(self.map.remove(&id).is_some());
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for (_ns, names) in self.names.iter_mut() {
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let mut remove = Vec::with_capacity(1);
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for (name, name_id) in names.iter() {
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if name_id == &id {
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remove.push(name.clone());
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}
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}
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for name in remove {
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assert!(names.remove(&name).is_some());
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}
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}
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}
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}
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/// Schemes list
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static SCHEMES: Once<RwLock<SchemeList>> = Once::new();
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/// Initialize schemes, called if needed
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fn init_schemes() -> RwLock<SchemeList> {
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RwLock::new(SchemeList::new())
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}
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/// Get the global schemes list, const
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pub fn schemes() -> RwLockReadGuard<'static, SchemeList> {
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SCHEMES.call_once(init_schemes).read()
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}
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/// Get the global schemes list, mutable
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pub fn schemes_mut() -> RwLockWriteGuard<'static, SchemeList> {
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SCHEMES.call_once(init_schemes).write()
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}
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#[allow(unused_variables)]
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pub trait KernelScheme: Scheme + Send + Sync + 'static {
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fn as_filetable(&self, number: usize) -> Result<Arc<RwLock<Vec<Option<FileDescriptor>>>>> {
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Err(Error::new(EBADF))
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}
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fn as_addrspace(&self, number: usize) -> Result<Arc<RwLock<AddrSpace>>> {
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Err(Error::new(EBADF))
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}
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fn as_sigactions(&self, number: usize) -> Result<Arc<RwLock<Vec<(crate::syscall::data::SigAction, usize)>>>> {
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Err(Error::new(EBADF))
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}
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fn kfmap(&self, number: usize, addr_space: &Arc<RwLock<AddrSpace>>, map: &crate::syscall::data::Map, consume: bool) -> Result<usize> {
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Err(Error::new(EOPNOTSUPP))
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}
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fn kfunmap(&self, number: usize, offset: usize, size: usize, flags: MunmapFlags) -> Result<()> {
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Err(Error::new(EOPNOTSUPP))
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}
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fn kopen(&self, path: &str, flags: usize, caller: CallerCtx) -> Result<OpenResult> {
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self.open(path, flags, caller.uid, caller.gid).map(OpenResult::SchemeLocal)
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}
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fn kdup(&self, old_id: usize, buf: UserSliceRo, _caller: CallerCtx) -> Result<OpenResult> {
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Err(Error::new(EOPNOTSUPP))
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}
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fn kwrite(&self, id: usize, buf: UserSliceRo) -> Result<usize> {
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Err(Error::new(EBADF))
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}
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fn kread(&self, id: usize, buf: UserSliceWo) -> Result<usize> {
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Err(Error::new(EBADF))
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}
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fn kfpath(&self, id: usize, buf: UserSliceWo) -> Result<usize> {
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Err(Error::new(EBADF))
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}
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fn kfutimens(&self, id: usize, buf: UserSliceRo) -> Result<usize> {
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Err(Error::new(EBADF))
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}
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fn kfstat(&self, id: usize, buf: UserSliceWo) -> Result<usize> {
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Err(Error::new(EBADF))
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}
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fn kfstatvfs(&self, id: usize, buf: UserSliceWo) -> Result<usize> {
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Err(Error::new(EBADF))
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}
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// TODO: This demonstrates why we need to transition away from a dyn trait.
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fn as_user_inner(&self) -> Option<Result<Arc<UserInner>>> { None }
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}
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#[derive(Debug)]
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pub enum OpenResult {
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SchemeLocal(usize),
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External(Arc<RwLock<FileDescription>>),
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}
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pub fn current_caller_ctx() -> Result<CallerCtx> {
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match crate::context::current()?.read() {
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ref context => Ok(CallerCtx { pid: context.id.into(), uid: context.euid, gid: context.egid }),
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}
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}
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