asterinas/kernel/src/syscall/truncate.rs

64 lines
1.8 KiB
Rust

// SPDX-License-Identifier: MPL-2.0
use super::SyscallReturn;
use crate::{
fs,
fs::{
file_table::{FileDesc, get_file_fast},
path::{AT_FDCWD, FsPath},
utils::PATH_MAX,
},
prelude::*,
process::ResourceType,
};
pub fn sys_ftruncate(fd: FileDesc, len: isize, ctx: &Context) -> Result<SyscallReturn> {
debug!("fd = {}, length = {}", fd, len);
check_length(len, ctx)?;
let mut file_table = ctx.thread_local.borrow_file_table_mut();
let file = get_file_fast!(&mut file_table, fd);
file.resize(len as usize)?;
fs::notify::on_change(file.path());
Ok(SyscallReturn::Return(0))
}
pub fn sys_truncate(path_ptr: Vaddr, len: isize, ctx: &Context) -> Result<SyscallReturn> {
let path_name = ctx.user_space().read_cstring(path_ptr, PATH_MAX)?;
debug!("path = {:?}, length = {}", path_name, len);
check_length(len, ctx)?;
let dir_path = {
let path_name = path_name.to_string_lossy();
let fs_path = FsPath::from_fd_and_path(AT_FDCWD, &path_name)?;
ctx.thread_local
.borrow_fs()
.resolver()
.read()
.lookup(&fs_path)?
};
dir_path.resize(len as usize)?;
fs::notify::on_change(&dir_path);
Ok(SyscallReturn::Return(0))
}
#[inline]
fn check_length(len: isize, ctx: &Context) -> Result<()> {
if len < 0 {
return_errno_with_message!(Errno::EINVAL, "length is negative");
}
let max_file_size = {
let resource_limits = ctx.process.resource_limits();
resource_limits
.get_rlimit(ResourceType::RLIMIT_FSIZE)
.get_cur() as usize
};
if len as usize > max_file_size {
return_errno_with_message!(Errno::EFBIG, "length is larger than the maximum file size");
}
Ok(())
}