45 lines
1.6 KiB
Rust
45 lines
1.6 KiB
Rust
use core::{mem, slice};
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use arch::paging::{ActivePageTable, Page, VirtualAddress, entry};
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use syscall::error::*;
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fn validate(address: usize, size: usize, flags: entry::EntryFlags) -> Result<()> {
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let active_table = unsafe { ActivePageTable::new() };
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let start_page = Page::containing_address(VirtualAddress::new(address));
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let end_page = Page::containing_address(VirtualAddress::new(address + size - 1));
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for page in Page::range_inclusive(start_page, end_page) {
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if let Some(page_flags) = active_table.translate_page_flags(page) {
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if ! page_flags.contains(flags) {
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//println!("{:X}: Not {:?}", page.start_address().get(), flags);
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return Err(Error::new(EFAULT));
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}
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} else {
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//println!("{:X}: Not found", page.start_address().get());
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return Err(Error::new(EFAULT));
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}
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}
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Ok(())
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}
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/// Convert a pointer and length to slice, if valid
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pub fn validate_slice<T>(ptr: *const T, len: usize) -> Result<&'static [T]> {
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if len == 0 {
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Ok(&[])
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} else {
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validate(ptr as usize, len * mem::size_of::<T>(), entry::PRESENT /* TODO | entry::USER_ACCESSIBLE */)?;
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Ok(unsafe { slice::from_raw_parts(ptr, len) })
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}
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}
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/// Convert a pointer and length to slice, if valid
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pub fn validate_slice_mut<T>(ptr: *mut T, len: usize) -> Result<&'static mut [T]> {
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if len == 0 {
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Ok(&mut [])
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} else {
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validate(ptr as usize, len * mem::size_of::<T>(), entry::PRESENT | entry::WRITABLE /* TODO | entry::USER_ACCESSIBLE */)?;
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Ok(unsafe { slice::from_raw_parts_mut(ptr, len) })
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}
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}
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