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解决userbufferwriter的长度错误问题，并修复gettimeofday的pagefault问题 (#349)

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* 解决userbufferwriter的长度错误问题，并修复gettimeofday的pagefault问题
This commit is contained in:
LoGin
2023-08-28 15:29:00 +08:00
committed by GitHub
parent ddb9d91712
commit f5df0e79c6
3 changed files with 27 additions and 48 deletions
kernel/src
syscall
mod.rsuser_access.rs
time
syscall.rs

30
kernel/src/syscall/mod.rs

@ -435,7 +435,7 @@ impl Syscall {
let fd = args[0] as i32;
let buf_vaddr = args[1];
let len = args[2];
let virt_addr = VirtAddr::new(buf_vaddr);
let virt_addr: VirtAddr = VirtAddr::new(buf_vaddr);
// 判断缓冲区是否来自用户态，进行权限校验
let res = if from_user && verify_area(virt_addr, len as usize).is_err() {
// 来自用户态，而buffer在内核态，这样的操作不被允许
@ -545,7 +545,7 @@ impl Syscall {
let fd = args[0] as i32;
let buf_vaddr = args[1];
let len = args[2];
let virt_addr = VirtAddr::new(buf_vaddr);
let virt_addr: VirtAddr = VirtAddr::new(buf_vaddr);
// 判断缓冲区是否来自用户态，进行权限校验
let res = if from_user && verify_area(virt_addr, len as usize).is_err() {
// 来自用户态，而buffer在内核态，这样的操作不被允许
@ -653,11 +653,7 @@ impl Syscall {
SYS_CLOCK => Self::clock(),
SYS_PIPE => {
let pipefd = args[0] as *mut c_int;
match UserBufferWriter::new(
pipefd,
core::mem::size_of::<[c_int; 2]>() as usize,
from_user,
) {
match UserBufferWriter::new(pipefd, core::mem::size_of::<[c_int; 2]>(), from_user) {
Err(e) => Err(e),
Ok(mut user_buffer) => match user_buffer.buffer::<i32>(0) {
Err(e) => Err(e),
@ -884,25 +880,7 @@ impl Syscall {
SYS_GETTIMEOFDAY => {
let timeval = args[0] as *mut PosixTimeval;
let timezone_ptr = args[1] as *mut PosixTimeZone;
match UserBufferWriter::new(timeval, core::mem::size_of::<PosixTimeval>(), true) {
Err(e) => Err(e),
Ok(_) => {
match UserBufferWriter::new(
timezone_ptr,
core::mem::size_of::<PosixTimeZone>(),
true,
) {
Err(e) => Err(e),
Ok(_) => {
if !timeval.is_null() {
Self::gettimeofday(timeval, timezone_ptr)
} else {
Err(SystemError::EFAULT)
}
}
}
}
}
Self::gettimeofday(timeval, timezone_ptr)
}
SYS_MMAP => {
let len = page_align_up(args[1]);

12
kernel/src/syscall/user_access.rs

@ -258,19 +258,11 @@ impl<'a> UserBufferWriter<'a> {
/// @return 构造成功返回UserbufferWriter实例，否则返回错误码
///
pub fn new<U>(addr: *mut U, len: usize, from_user: bool) -> Result<Self, SystemError> {
if from_user
&& verify_area(
VirtAddr::new(addr as usize),
(len * core::mem::size_of::<U>()) as usize,
)
.is_err()
{
if from_user && verify_area(VirtAddr::new(addr as usize), len).is_err() {
return Err(SystemError::EFAULT);
}
return Ok(Self {
buffer: unsafe {
core::slice::from_raw_parts_mut(addr as *mut u8, len * core::mem::size_of::<U>())
},
buffer: unsafe { core::slice::from_raw_parts_mut(addr as *mut u8, len) },
});
}