Refactor project structure

kernel/aster-nix/src/syscall/truncate.rs

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::{SyscallReturn, SYS_FTRUNCATE, SYS_TRUNCATE};
+use crate::{
+    fs::{
+        file_table::FileDescripter,
+        fs_resolver::{FsPath, AT_FDCWD},
+        utils::PATH_MAX,
+    },
+    log_syscall_entry,
+    prelude::*,
+    process::ResourceType,
+    util::read_cstring_from_user,
+};
+
+pub fn sys_ftruncate(fd: FileDescripter, len: isize) -> Result<SyscallReturn> {
+    log_syscall_entry!(SYS_FTRUNCATE);
+    debug!("fd = {}, lentgh = {}", fd, len);
+
+    check_length(len)?;
+
+    let current = current!();
+    let file_table = current.file_table().lock();
+    let file = file_table.get_file(fd)?;
+    file.resize(len as usize)?;
+    Ok(SyscallReturn::Return(0))
+}
+
+pub fn sys_truncate(path_ptr: Vaddr, len: isize) -> Result<SyscallReturn> {
+    log_syscall_entry!(SYS_TRUNCATE);
+    let path = read_cstring_from_user(path_ptr, PATH_MAX)?;
+    debug!("path = {:?}, length = {}", path, len);
+
+    check_length(len)?;
+
+    let current = current!();
+    let dentry = {
+        let path = path.to_string_lossy();
+        if path.is_empty() {
+            return_errno_with_message!(Errno::ENOENT, "path is empty");
+        }
+        let fs_path = FsPath::new(AT_FDCWD, path.as_ref())?;
+        current.fs().read().lookup(&fs_path)?
+    };
+    dentry.resize(len as usize)?;
+    Ok(SyscallReturn::Return(0))
+}
+
+#[inline]
+fn check_length(len: isize) -> Result<()> {
+    if len < 0 {
+        return_errno_with_message!(Errno::EINVAL, "length is negative");
+    }
+
+    let max_file_size = {
+        let current = current!();
+        let resource_limits = current.resource_limits().lock();
+        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(())
+}