From 504e93d11b6b1a374c2da463bacccec59dac3feb Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jeremy@system76.com>
Date: Mon, 28 Jan 2019 19:27:20 -0700
Subject: [PATCH] Store file descriptor for mapped files until they are
unmapped
---
src/context/memory.rs | 33 ++++++++++++++++++++++-----------
src/scheme/user.rs | 32 ++++++++++++++++++++------------
2 files changed, 42 insertions(+), 23 deletions(-)
diff --git a/src/context/memory.rs b/src/context/memory.rs
index f41640ba..3aa5899a 100644
--- a/src/context/memory.rs
+++ b/src/context/memory.rs
@@ -4,6 +4,7 @@ use core::intrinsics;
use spin::Mutex;
use arch::paging::PAGE_SIZE;
+use context::file::FileDescriptor;
use ipi::{ipi, IpiKind, IpiTarget};
use memory::Frame;
use paging::{ActivePageTable, InactivePageTable, Page, PageIter, PhysicalAddress, VirtualAddress};
@@ -16,7 +17,9 @@ pub struct Grant {
start: VirtualAddress,
size: usize,
flags: EntryFlags,
- mapped: bool
+ mapped: bool,
+ //TODO: This is probably a very heavy way to keep track of fmap'd files, perhaps move to the context?
+ desc_opt: Option<FileDescriptor>,
}
impl Grant {
@@ -37,9 +40,10 @@ impl Grant {
Grant {
start: to,
- size: size,
- flags: flags,
- mapped: true
+ size,
+ flags,
+ mapped: true,
+ desc_opt: None,
}
}
@@ -59,13 +63,14 @@ impl Grant {
Grant {
start: to,
- size: size,
- flags: flags,
- mapped: true
+ size,
+ flags,
+ mapped: true,
+ desc_opt: None,
}
}
- pub fn map_inactive(from: VirtualAddress, to: VirtualAddress, size: usize, flags: EntryFlags, new_table: &mut InactivePageTable, temporary_page: &mut TemporaryPage) -> Grant {
+ pub fn map_inactive(from: VirtualAddress, to: VirtualAddress, size: usize, flags: EntryFlags, desc_opt: Option<FileDescriptor>, new_table: &mut InactivePageTable, temporary_page: &mut TemporaryPage) -> Grant {
let mut active_table = unsafe { ActivePageTable::new() };
//TODO: Do not allocate
@@ -93,9 +98,10 @@ impl Grant {
Grant {
start: to,
- size: size,
- flags: flags,
- mapped: true
+ size,
+ flags,
+ mapped: true,
+ desc_opt,
}
}
@@ -147,6 +153,11 @@ impl Grant {
ipi(IpiKind::Tlb, IpiTarget::Other);
+ if let Some(desc) = self.desc_opt.take() {
+ //TODO: This imposes a large cost on unmapping, but that cost cannot be avoided without modifying fmap and funmap
+ let _ = desc.close();
+ }
+
self.mapped = false;
}
}
diff --git a/src/scheme/user.rs b/src/scheme/user.rs
index 442c7650..df1c5560 100644
--- a/src/scheme/user.rs
+++ b/src/scheme/user.rs
@@ -6,12 +6,13 @@ use core::{mem, slice, usize};
use spin::{Mutex, RwLock};
use context::{self, Context};
+use context::file::FileDescriptor;
use context::memory::Grant;
use event;
use paging::{InactivePageTable, Page, VirtualAddress};
use paging::entry::EntryFlags;
use paging::temporary_page::TemporaryPage;
-use scheme::{AtomicSchemeId, ATOMIC_SCHEMEID_INIT, SchemeId};
+use scheme::{AtomicSchemeId, ATOMIC_SCHEMEID_INIT, SchemeId, FileHandle};
use sync::{WaitQueue, WaitMap};
use syscall::data::{Map, Packet, Stat, StatVfs, TimeSpec};
use syscall::error::*;
@@ -28,7 +29,7 @@ pub struct UserInner {
next_id: AtomicU64,
context: Weak<RwLock<Context>>,
todo: WaitQueue<Packet>,
- fmap: Mutex<BTreeMap<u64, (Weak<RwLock<Context>>, Map)>>,
+ fmap: Mutex<BTreeMap<u64, (Weak<RwLock<Context>>, FileDescriptor, Map)>>,
done: WaitMap<u64, usize>
}
@@ -78,14 +79,14 @@ impl UserInner {
}
pub fn capture(&self, buf: &[u8]) -> Result<usize> {
- UserInner::capture_inner(&self.context, buf.as_ptr() as usize, buf.len(), PROT_READ)
+ UserInner::capture_inner(&self.context, buf.as_ptr() as usize, buf.len(), PROT_READ, None)
}
pub fn capture_mut(&self, buf: &mut [u8]) -> Result<usize> {
- UserInner::capture_inner(&self.context, buf.as_mut_ptr() as usize, buf.len(), PROT_WRITE)
+ UserInner::capture_inner(&self.context, buf.as_mut_ptr() as usize, buf.len(), PROT_WRITE, None)
}
- fn capture_inner(context_weak: &Weak<RwLock<Context>>, address: usize, size: usize, flags: usize) -> Result<usize> {
+ fn capture_inner(context_weak: &Weak<RwLock<Context>>, address: usize, size: usize, flags: usize, desc_opt: Option<FileDescriptor>) -> Result<usize> {
//TODO: Abstract with other grant creation
if size == 0 {
Ok(0)
@@ -133,6 +134,7 @@ impl UserInner {
VirtualAddress::new(to_address),
full_size,
entry_flags,
+ desc_opt,
&mut new_table,
&mut temporary_page
));
@@ -187,9 +189,12 @@ impl UserInner {
_ => println!("Unknown scheme -> kernel message {}", packet.a)
}
} else {
- if let Some((context_weak, map)) = self.fmap.lock().remove(&packet.id) {
+ if let Some((context_weak, desc, map)) = self.fmap.lock().remove(&packet.id) {
if let Ok(address) = Error::demux(packet.a) {
- packet.a = Error::mux(UserInner::capture_inner(&context_weak, address, map.size, map.flags));
+ //TODO: Protect against sharing addresses that are not page aligned
+ packet.a = Error::mux(UserInner::capture_inner(&context_weak, address, map.size, map.flags, Some(desc)));
+ } else {
+ let _ = desc.close();
}
}
@@ -308,18 +313,21 @@ impl Scheme for UserScheme {
fn fmap(&self, file: usize, map: &Map) -> Result<usize> {
let inner = self.inner.upgrade().ok_or(Error::new(ENODEV))?;
- let address = inner.capture(map)?;
-
- let (pid, uid, gid, context_lock) = {
+ let (pid, uid, gid, context_lock, desc) = {
let contexts = context::contexts();
let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
let context = context_lock.read();
- (context.id, context.euid, context.egid, Arc::downgrade(&context_lock))
+ let desc = context.get_file(FileHandle(file))
+ .ok_or(Error::new(EBADF))?
+ .clone();
+ (context.id, context.euid, context.egid, Arc::downgrade(&context_lock), desc)
};
+ let address = inner.capture(map)?;
+
let id = inner.next_id.fetch_add(1, Ordering::SeqCst);
- inner.fmap.lock().insert(id, (context_lock, *map));
+ inner.fmap.lock().insert(id, (context_lock, desc, *map));
let result = inner.call_inner(Packet {
id: id,
--
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