49 lines
1.3 KiB
Rust
49 lines
1.3 KiB
Rust
// SPDX-License-Identifier: MPL-2.0
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use super::SyscallReturn;
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use crate::{
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fs,
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fs::file_table::{get_file_fast, FileDesc},
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prelude::*,
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};
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pub fn sys_pread64(
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fd: FileDesc,
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user_buf_ptr: Vaddr,
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user_buf_len: usize,
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offset: i64,
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ctx: &Context,
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) -> Result<SyscallReturn> {
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debug!(
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"fd = {}, buf = 0x{:x}, user_buf_len = 0x{:x}, offset = 0x{:x}",
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fd, user_buf_ptr, user_buf_len, offset
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);
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if offset < 0 {
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return_errno_with_message!(Errno::EINVAL, "offset cannot be negative");
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}
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let mut file_table = ctx.thread_local.borrow_file_table_mut();
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let file = get_file_fast!(&mut file_table, fd);
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// TODO: Check (f.file->f_mode & FMODE_PREAD); We don't have f_mode in our FileLike trait
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if user_buf_len == 0 {
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return Ok(SyscallReturn::Return(0));
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}
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if offset.checked_add(user_buf_len as i64).is_none() {
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return_errno_with_message!(Errno::EINVAL, "offset + user_buf_len overflow");
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}
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let read_len = {
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let user_space = ctx.user_space();
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let mut writer = user_space.writer(user_buf_ptr, user_buf_len)?;
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file.read_at(offset as usize, &mut writer)?
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};
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if read_len > 0 {
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fs::notify::on_access(&file);
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}
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Ok(SyscallReturn::Return(read_len as _))
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}
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