From d3ecedefd98eae77fc69eef17e4019711ccd6b92 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Wed, 12 Jul 2023 15:33:18 +0200
Subject: [PATCH] Notify schemes when mmaps are unmapped.
---
src/context/memory.rs | 2 --
src/scheme/proc.rs | 6 ++----
src/scheme/user.rs | 21 ++++++++++++++++++++-
src/syscall/fs.rs | 12 +++++++++++-
syscall | 2 +-
5 files changed, 34 insertions(+), 9 deletions(-)
diff --git a/src/context/memory.rs b/src/context/memory.rs
index 09e0f402..36b447b7 100644
--- a/src/context/memory.rs
+++ b/src/context/memory.rs
@@ -34,8 +34,6 @@ pub fn map_flags(page_flags: PageFlags<RmmA>) -> MapFlags {
let mut flags = MapFlags::PROT_READ;
if page_flags.has_write() { flags |= MapFlags::PROT_WRITE; }
if page_flags.has_execute() { flags |= MapFlags::PROT_EXEC; }
- // TODO: MAP_SHARED/MAP_PRIVATE (requires that grants keep track of what they borrow and if
- // they borrow shared or CoW).
flags
}
diff --git a/src/scheme/proc.rs b/src/scheme/proc.rs
index 41537b5a..74aff40c 100644
--- a/src/scheme/proc.rs
+++ b/src/scheme/proc.rs
@@ -592,7 +592,7 @@ impl Scheme for ProcScheme {
match handle.info.operation {
Operation::AwaitingAddrSpaceChange { new, new_sp, new_ip } => {
- stop_context(handle.info.pid, |context: &mut Context| unsafe {
+ let prev_addr_space = stop_context(handle.info.pid, |context: &mut Context| unsafe {
if let Some(saved_regs) = ptrace::regs_for_mut(context) {
#[cfg(target_arch = "aarch64")]
{
@@ -615,9 +615,7 @@ impl Scheme for ProcScheme {
context.clone_entry = Some([new_ip, new_sp]);
}
- let _prev_addr_space = context.set_addr_space(new);
-
- Ok(())
+ Ok(context.set_addr_space(new))
})?;
let _ = ptrace::send_event(crate::syscall::ptrace_event!(PTRACE_EVENT_ADDRSPACE_SWITCH, 0));
}
diff --git a/src/scheme/user.rs b/src/scheme/user.rs
index 62db1810..b0a1c090 100644
--- a/src/scheme/user.rs
+++ b/src/scheme/user.rs
@@ -543,10 +543,15 @@ impl UserInner {
};
let page_count_nz = NonZeroUsize::new(page_count).expect("already validated map.size != 0");
- let dst_base = dst_addr_space.write().mmap(dst_base, page_count_nz, map.flags | MAP_FIXED_NOREPLACE, &mut Vec::new(), |dst_base, flags, mapper, flusher| {
+ let mut notify_files = Vec::new();
+ let dst_base = dst_addr_space.write().mmap(dst_base, page_count_nz, map.flags | MAP_FIXED_NOREPLACE, &mut notify_files, |dst_base, flags, mapper, flusher| {
Grant::borrow_fmap(PageSpan::new(dst_base, page_count), page_flags(map.flags), file_ref, src, mapper, flusher)
})?;
+ for map in notify_files {
+ let _ = map.unmap();
+ }
+
Ok(dst_base.start_address().data())
}
}
@@ -829,6 +834,20 @@ impl KernelScheme for UserScheme {
inner.fmap_inner(Arc::clone(addr_space), file, map)
}
+ fn kfunmap(&self, number: usize, offset: usize, size: usize) -> Result<()> {
+ let inner = self.inner.upgrade().ok_or(Error::new(ENODEV))?;
+
+ let res = inner.call_extended(CallerCtx {
+ pid: context::context_id().into(),
+ uid: offset as u32,
+ gid: (offset >> 32) as u32,
+ }, [KSMSG_MUNMAP, number, size, 0])?;
+
+ match res {
+ Response::Regular(_) => Ok(()),
+ Response::Fd(_) => Err(Error::new(EIO)),
+ }
+ }
fn as_user_inner(&self) -> Option<Result<Arc<UserInner>>> {
Some(self.inner.upgrade().ok_or(Error::new(ENODEV)))
diff --git a/src/syscall/fs.rs b/src/syscall/fs.rs
index 68e399c1..cc97aee3 100644
--- a/src/syscall/fs.rs
+++ b/src/syscall/fs.rs
@@ -387,6 +387,12 @@ pub fn fstat(fd: FileHandle, user_buf: UserSliceWo) -> Result<usize> {
}
pub fn funmap(virtual_address: usize, length: usize) -> Result<usize> {
+ // Partial lengths in funmap are allowed according to POSIX, but not particularly meaningful;
+ // since the memory needs to SIGSEGV if later read, the entire page needs to disappear.
+ //
+ // Thus, while (temporarily) allowing unaligned lengths for compatibility, aligning the length
+ // should be done by libc.
+
let length_aligned = length.next_multiple_of(PAGE_SIZE);
if length != length_aligned {
log::warn!("funmap passed length {:#x} instead of {:#x}", length, length_aligned);
@@ -395,7 +401,11 @@ pub fn funmap(virtual_address: usize, length: usize) -> Result<usize> {
let addr_space = Arc::clone(context::current()?.read().addr_space()?);
let span = PageSpan::validate_nonempty(VirtualAddress::new(virtual_address), length_aligned).ok_or(Error::new(EINVAL))?;
let unpin = false;
- addr_space.write().munmap(span, unpin)?;
+ let notify = addr_space.write().munmap(span, unpin)?;
+
+ for map in notify {
+ let _ = map.unmap();
+ }
Ok(0)
}
diff --git a/syscall b/syscall
index ff149946..ed28083b 160000
--- a/syscall
+++ b/syscall
@@ -1 +1 @@
-Subproject commit ff149946c07628dde39db05997e221b5024ccb95
+Subproject commit ed28083b73ed2b163e2d64ee3753f1d6ff6c94d1
--
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