4lDO2
576 lines
18 KiB
Rust
576 lines
18 KiB
Rust
use alloc::{
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boxed::Box,
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collections::VecDeque,
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string::{String, ToString},
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sync::Arc,
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vec::Vec,
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};
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use core::{
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alloc::GlobalAlloc,
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cmp::Ordering,
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mem,
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};
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use spin::RwLock;
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use crate::arch::{interrupt::InterruptStack, paging::{PAGE_SIZE, RmmA, RmmArch}};
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use crate::common::unique::Unique;
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use crate::context::arch;
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use crate::context::file::{FileDescriptor, FileDescription};
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use crate::context::memory::{AddrSpace, new_addrspace, UserGrants};
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use crate::ipi::{ipi, IpiKind, IpiTarget};
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use crate::memory::Enomem;
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use crate::scheme::{SchemeNamespace, FileHandle};
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use crate::sync::WaitMap;
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use crate::syscall::data::SigAction;
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use crate::syscall::error::{Result, Error, ENOMEM, ESRCH};
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use crate::syscall::flag::{SIG_DFL, SigActionFlags};
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/// Unique identifier for a context (i.e. `pid`).
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use ::core::sync::atomic::AtomicUsize;
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int_like!(ContextId, AtomicContextId, usize, AtomicUsize);
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/// The status of a context - used for scheduling
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/// See `syscall::process::waitpid` and the `sync` module for examples of usage
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#[derive(Copy, Clone, Debug, Eq, PartialEq)]
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pub enum Status {
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Runnable,
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Blocked,
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Stopped(usize),
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Exited(usize),
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}
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#[derive(Copy, Clone, Debug)]
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pub struct WaitpidKey {
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pub pid: Option<ContextId>,
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pub pgid: Option<ContextId>,
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}
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impl Ord for WaitpidKey {
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fn cmp(&self, other: &WaitpidKey) -> Ordering {
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// If both have pid set, compare that
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if let Some(s_pid) = self.pid {
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if let Some(o_pid) = other.pid {
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return s_pid.cmp(&o_pid);
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}
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}
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// If both have pgid set, compare that
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if let Some(s_pgid) = self.pgid {
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if let Some(o_pgid) = other.pgid {
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return s_pgid.cmp(&o_pgid);
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}
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}
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// If either has pid set, it is greater
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if self.pid.is_some() {
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return Ordering::Greater;
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}
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if other.pid.is_some() {
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return Ordering::Less;
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}
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// If either has pgid set, it is greater
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if self.pgid.is_some() {
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return Ordering::Greater;
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}
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if other.pgid.is_some() {
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return Ordering::Less;
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}
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// If all pid and pgid are None, they are equal
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Ordering::Equal
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}
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}
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impl PartialOrd for WaitpidKey {
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fn partial_cmp(&self, other: &WaitpidKey) -> Option<Ordering> {
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Some(self.cmp(other))
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}
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}
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impl PartialEq for WaitpidKey {
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fn eq(&self, other: &WaitpidKey) -> bool {
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self.cmp(other) == Ordering::Equal
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}
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}
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impl Eq for WaitpidKey {}
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pub struct ContextSnapshot {
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// Copy fields
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pub id: ContextId,
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pub pgid: ContextId,
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pub ppid: ContextId,
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pub ruid: u32,
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pub rgid: u32,
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pub rns: SchemeNamespace,
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pub euid: u32,
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pub egid: u32,
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pub ens: SchemeNamespace,
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pub sigmask: [u64; 2],
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pub umask: usize,
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pub status: Status,
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pub status_reason: &'static str,
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pub running: bool,
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pub cpu_id: Option<usize>,
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pub ticks: u64,
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pub syscall: Option<(usize, usize, usize, usize, usize, usize)>,
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// Clone fields
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//TODO: is there a faster way than allocation?
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pub name: Box<str>,
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pub files: Vec<Option<FileDescription>>,
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// pub cwd: Box<[u8]>,
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}
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impl ContextSnapshot {
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//TODO: Should this accept &mut Context to ensure name/files will not change?
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pub fn new(context: &Context) -> Self {
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let name = context.name.read().clone();
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let mut files = Vec::new();
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for descriptor_opt in context.files.read().iter() {
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let description = if let Some(descriptor) = descriptor_opt {
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let description = descriptor.description.read();
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Some(FileDescription {
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namespace: description.namespace,
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scheme: description.scheme,
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number: description.number,
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flags: description.flags,
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})
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} else {
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None
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};
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files.push(description);
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}
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Self {
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id: context.id,
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pgid: context.pgid,
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ppid: context.ppid,
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ruid: context.ruid,
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rgid: context.rgid,
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rns: context.rns,
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euid: context.euid,
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egid: context.egid,
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ens: context.ens,
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sigmask: context.sigmask,
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umask: context.umask,
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status: context.status,
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status_reason: context.status_reason,
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running: context.running,
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cpu_id: context.cpu_id,
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ticks: context.ticks,
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syscall: context.syscall,
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name,
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files,
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}
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}
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}
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/// A context, which identifies either a process or a thread
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#[derive(Debug)]
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pub struct Context {
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/// The ID of this context
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pub id: ContextId,
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/// The group ID of this context
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pub pgid: ContextId,
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/// The ID of the parent context
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pub ppid: ContextId,
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/// The real user id
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pub ruid: u32,
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/// The real group id
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pub rgid: u32,
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/// The real namespace id
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pub rns: SchemeNamespace,
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/// The effective user id
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pub euid: u32,
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/// The effective group id
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pub egid: u32,
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/// The effective namespace id
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pub ens: SchemeNamespace,
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/// Signal mask
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pub sigmask: [u64; 2],
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/// Process umask
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pub umask: usize,
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/// Status of context
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pub status: Status,
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pub status_reason: &'static str,
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/// Context running or not
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pub running: bool,
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/// CPU ID, if locked
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pub cpu_id: Option<usize>,
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/// Number of timer ticks executed
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pub ticks: u64,
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/// Current system call
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pub syscall: Option<(usize, usize, usize, usize, usize, usize)>,
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/// Head buffer to use when system call buffers are not page aligned
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pub syscall_head: AlignedBox<[u8; PAGE_SIZE], PAGE_SIZE>,
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/// Tail buffer to use when system call buffers are not page aligned
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pub syscall_tail: AlignedBox<[u8; PAGE_SIZE], PAGE_SIZE>,
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/// Context is halting parent
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pub vfork: bool,
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/// Context is being waited on
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pub waitpid: Arc<WaitMap<WaitpidKey, (ContextId, usize)>>,
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/// Context should handle pending signals
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pub pending: VecDeque<u8>,
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/// Context should wake up at specified time
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pub wake: Option<(u64, u64)>,
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/// The architecture specific context
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pub arch: arch::Context,
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/// Kernel FX - used to store SIMD and FPU registers on context switch
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pub kfx: Option<AlignedBox<[u8; {arch::KFX_SIZE}], {arch::KFX_ALIGN}>>,
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/// Kernel stack
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pub kstack: Option<Box<[u8]>>,
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/// Kernel signal backup: Registers, Kernel FX, Kernel Stack, Signal number
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pub ksig: Option<(arch::Context, Option<AlignedBox<[u8; arch::KFX_SIZE], {arch::KFX_ALIGN}>>, Option<Box<[u8]>>, u8)>,
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/// Restore ksig context on next switch
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pub ksig_restore: bool,
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/// Address space containing a page table lock, and grants. Normally this will have a value,
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/// but can be None while the context is being reaped.
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pub addr_space: Option<Arc<RwLock<AddrSpace>>>,
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/// The name of the context
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pub name: Arc<RwLock<Box<str>>>,
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/// The current working directory
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pub cwd: Arc<RwLock<String>>,
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/// The open files in the scheme
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pub files: Arc<RwLock<Vec<Option<FileDescriptor>>>>,
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/// Signal actions
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pub actions: Arc<RwLock<Vec<(SigAction, usize)>>>,
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/// The pointer to the user-space registers, saved after certain
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/// interrupts. This pointer is somewhere inside kstack, and the
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/// kstack address at the time of creation is the first element in
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/// this tuple.
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pub regs: Option<(usize, Unique<InterruptStack>)>,
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/// A somewhat hacky way to initially stop a context when creating
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/// a new instance of the proc: scheme, entirely separate from
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/// signals or any other way to restart a process.
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pub ptrace_stop: bool,
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/// A pointer to the signal stack. If this is unset, none of the sigactions can be anything
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/// else than SIG_DFL, otherwise signals will not be delivered. Userspace is responsible for
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/// setting this.
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pub sigstack: Option<usize>,
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/// An even hackier way to pass the return entry point and stack pointer to new contexts while
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/// implementing clone. Before a context has returned to userspace, its IntRegisters cannot be
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/// set since there is no interrupt stack (unless the kernel stack is copied, but that is in my
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/// opinion hackier and less efficient than this (and UB to do in Rust)).
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pub clone_entry: Option<[usize; 2]>,
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}
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// Necessary because GlobalAlloc::dealloc requires the layout to be the same, and therefore Box
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// cannot be used for increased alignment directly.
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// TODO: move to common?
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pub struct AlignedBox<T, const ALIGN: usize> {
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inner: Unique<T>,
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}
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pub unsafe trait ValidForZero {}
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unsafe impl<const N: usize> ValidForZero for [u8; N] {}
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impl<T, const ALIGN: usize> AlignedBox<T, ALIGN> {
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const LAYOUT: core::alloc::Layout = {
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const fn max(a: usize, b: usize) -> usize {
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if a > b { a } else { b }
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}
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match core::alloc::Layout::from_size_align(mem::size_of::<T>(), max(mem::align_of::<T>(), ALIGN)) {
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Ok(l) => l,
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Err(_) => panic!("layout validation failed at compile time"),
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}
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};
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#[inline(always)]
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pub fn try_zeroed() -> Result<Self, Enomem>
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where
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T: ValidForZero,
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{
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Ok(unsafe {
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let ptr = crate::ALLOCATOR.alloc_zeroed(Self::LAYOUT);
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if ptr.is_null() {
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return Err(Enomem)?;
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}
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Self {
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inner: Unique::new_unchecked(ptr.cast()),
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}
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})
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}
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}
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impl<T, const ALIGN: usize> core::fmt::Debug for AlignedBox<T, ALIGN> {
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fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
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write!(f, "[aligned box at {:p}, size {} alignment {}]", self.inner.as_ptr(), mem::size_of::<T>(), mem::align_of::<T>())
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}
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}
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impl<T, const ALIGN: usize> Drop for AlignedBox<T, ALIGN> {
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fn drop(&mut self) {
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unsafe {
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core::ptr::drop_in_place(self.inner.as_ptr());
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crate::ALLOCATOR.dealloc(self.inner.as_ptr().cast(), Self::LAYOUT);
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}
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}
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}
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impl<T, const ALIGN: usize> core::ops::Deref for AlignedBox<T, ALIGN> {
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type Target = T;
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fn deref(&self) -> &Self::Target {
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unsafe { &*self.inner.as_ptr() }
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}
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}
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impl<T, const ALIGN: usize> core::ops::DerefMut for AlignedBox<T, ALIGN> {
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fn deref_mut(&mut self) -> &mut Self::Target {
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unsafe { &mut *self.inner.as_ptr() }
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}
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}
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impl<T: Clone + ValidForZero, const ALIGN: usize> Clone for AlignedBox<T, ALIGN> {
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fn clone(&self) -> Self {
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let mut new = Self::try_zeroed().unwrap_or_else(|_| alloc::alloc::handle_alloc_error(Self::LAYOUT));
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T::clone_from(&mut new, self);
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new
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}
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}
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impl Context {
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pub fn new(id: ContextId) -> Result<Context> {
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let syscall_head = AlignedBox::try_zeroed()?;
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let syscall_tail = AlignedBox::try_zeroed()?;
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let mut this = Context {
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id,
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pgid: id,
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ppid: ContextId::from(0),
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ruid: 0,
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rgid: 0,
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rns: SchemeNamespace::from(0),
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euid: 0,
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egid: 0,
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ens: SchemeNamespace::from(0),
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sigmask: [0; 2],
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umask: 0o022,
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status: Status::Blocked,
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status_reason: "",
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running: false,
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cpu_id: None,
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ticks: 0,
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syscall: None,
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syscall_head,
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syscall_tail,
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vfork: false,
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waitpid: Arc::new(WaitMap::new()),
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pending: VecDeque::new(),
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wake: None,
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arch: arch::Context::new(),
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kfx: None,
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kstack: None,
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ksig: None,
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ksig_restore: false,
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addr_space: None,
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name: Arc::new(RwLock::new(String::new().into_boxed_str())),
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cwd: Arc::new(RwLock::new(String::new())),
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files: Arc::new(RwLock::new(Vec::new())),
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actions: Arc::new(RwLock::new(vec![(
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SigAction {
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sa_handler: unsafe { mem::transmute(SIG_DFL) },
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sa_mask: [0; 2],
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sa_flags: SigActionFlags::empty(),
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},
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0
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); 128])),
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regs: None,
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ptrace_stop: false,
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sigstack: None,
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clone_entry: None,
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};
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let _ = this.set_addr_space(new_addrspace()?);
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Ok(this)
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}
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/// Make a relative path absolute
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/// Given a cwd of "scheme:/path"
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/// This function will turn "foo" into "scheme:/path/foo"
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/// "/foo" will turn into "scheme:/foo"
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/// "bar:/foo" will be used directly, as it is already absolute
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pub fn canonicalize(&self, path: &str) -> String {
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let mut canon = if path.find(':').is_none() {
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let cwd = self.cwd.read();
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let mut canon = if !path.starts_with('/') {
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let mut c = cwd.clone();
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if ! c.ends_with('/') {
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c.push('/');
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}
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c
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} else {
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cwd[..cwd.find(':').map_or(1, |i| i + 1)].to_string()
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};
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canon.push_str(&path);
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canon
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} else {
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path.to_string()
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};
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// NOTE: assumes the scheme does not include anything like "../" or "./"
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let mut result = {
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let parts = canon.split('/')
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.rev()
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.scan(0, |nskip, part| {
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if part == "." {
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Some(None)
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} else if part == ".." {
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*nskip += 1;
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Some(None)
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} else if *nskip > 0 {
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*nskip -= 1;
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Some(None)
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} else {
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Some(Some(part))
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}
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})
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.filter_map(|x| x)
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.filter(|x| !x.is_empty())
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.collect::<Vec<_>>();
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parts
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.iter()
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.rev()
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.fold(String::new(), |mut string, &part| {
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string.push_str(part);
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string.push('/');
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string
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})
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};
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result.pop(); // remove extra '/'
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// replace with the root of the scheme if it's empty
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if result.is_empty() {
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let pos = canon.find(':')
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.map_or(canon.len(), |p| p + 1);
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canon.truncate(pos);
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canon
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} else {
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result
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}
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}
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/// Block the context, and return true if it was runnable before being blocked
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pub fn block(&mut self, reason: &'static str) -> bool {
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if self.status == Status::Runnable {
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self.status = Status::Blocked;
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self.status_reason = reason;
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true
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} else {
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false
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}
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}
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/// Unblock context, and return true if it was blocked before being marked runnable
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pub fn unblock(&mut self) -> bool {
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if self.status == Status::Blocked {
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self.status = Status::Runnable;
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self.status_reason = "";
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if let Some(cpu_id) = self.cpu_id {
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if cpu_id != crate::cpu_id() {
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// Send IPI if not on current CPU
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ipi(IpiKind::Wakeup, IpiTarget::Other);
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}
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}
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true
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} else {
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false
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}
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}
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/// Add a file to the lowest available slot.
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/// Return the file descriptor number or None if no slot was found
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pub fn add_file(&self, file: FileDescriptor) -> Option<FileHandle> {
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self.add_file_min(file, 0)
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}
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/// Add a file to the lowest available slot greater than or equal to min.
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/// Return the file descriptor number or None if no slot was found
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pub fn add_file_min(&self, file: FileDescriptor, min: usize) -> Option<FileHandle> {
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let mut files = self.files.write();
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for (i, file_option) in files.iter_mut().enumerate() {
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if file_option.is_none() && i >= min {
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*file_option = Some(file);
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return Some(FileHandle::from(i));
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}
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}
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let len = files.len();
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if len < super::CONTEXT_MAX_FILES {
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if len >= min {
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files.push(Some(file));
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Some(FileHandle::from(len))
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} else {
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drop(files);
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self.insert_file(FileHandle::from(min), file)
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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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/// Get a file
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pub fn get_file(&self, i: FileHandle) -> Option<FileDescriptor> {
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let files = self.files.read();
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if i.into() < files.len() {
|
|
files[i.into()].clone()
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
/// Insert a file with a specific handle number. This is used by dup2
|
|
/// Return the file descriptor number or None if the slot was not empty, or i was invalid
|
|
pub fn insert_file(&self, i: FileHandle, file: FileDescriptor) -> Option<FileHandle> {
|
|
let mut files = self.files.write();
|
|
if i.into() < super::CONTEXT_MAX_FILES {
|
|
while i.into() >= files.len() {
|
|
files.push(None);
|
|
}
|
|
if files[i.into()].is_none() {
|
|
files[i.into()] = Some(file);
|
|
Some(i)
|
|
} else {
|
|
None
|
|
}
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
/// Remove a file
|
|
// TODO: adjust files vector to smaller size if possible
|
|
pub fn remove_file(&self, i: FileHandle) -> Option<FileDescriptor> {
|
|
let mut files = self.files.write();
|
|
if i.into() < files.len() {
|
|
files[i.into()].take()
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
pub fn addr_space(&self) -> Result<&Arc<RwLock<AddrSpace>>> {
|
|
self.addr_space.as_ref().ok_or(Error::new(ESRCH))
|
|
}
|
|
#[must_use = "grants must be manually unmapped, otherwise it WILL panic!"]
|
|
pub fn set_addr_space(&mut self, addr_space: Arc<RwLock<AddrSpace>>) -> Option<Arc<RwLock<AddrSpace>>> {
|
|
let physaddr = addr_space.read().frame.utable.start_address();
|
|
if self.id == super::context_id() {
|
|
unsafe {
|
|
RmmA::set_table(physaddr);
|
|
}
|
|
}
|
|
|
|
self.arch.set_page_utable(physaddr.data());
|
|
self.addr_space.replace(addr_space)
|
|
}
|
|
|
|
pub fn init_fx(&mut self) -> Result<(), Enomem> {
|
|
let mut fx = AlignedBox::<[u8; arch::KFX_SIZE], {arch::KFX_ALIGN}>::try_zeroed()?;
|
|
self.arch.set_fx(fx.as_mut_ptr() as usize);
|
|
self.kfx = Some(fx);
|
|
Ok(())
|
|
}
|
|
}
|