feat:添加symlink系统调用 (#984)

* 添加symlink系统调用

* 修改FATInode的dname的获取逻辑

* 修改fat对Dname的处理,分离dname和inode缓存的key

---------

Co-authored-by: sparkzky <sparkhhhhhhhhh@outlook.com>
Co-authored-by: longjin <longjin@DragonOS.org>
This commit is contained in:
sparkzky 2024-10-20 20:56:11 +08:00 committed by GitHub
parent cae6182257
commit 01c18c64b1
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
14 changed files with 328 additions and 39 deletions

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@ -2,11 +2,11 @@ use alloc::string::ToString;
use core::cmp::Ordering;
use core::intrinsics::unlikely;
use core::{any::Any, fmt::Debug};
use hashbrown::HashMap;
use log::error;
use system_error::SystemError;
use alloc::{
collections::BTreeMap,
string::String,
sync::{Arc, Weak},
vec::Vec,
@ -36,6 +36,7 @@ use crate::{
};
use super::entry::FATFile;
use super::utils::{to_search_name, to_search_name_string};
use super::{
bpb::{BiosParameterBlock, FATType},
entry::{FATDir, FATDirEntry, FATDirIter, FATEntry},
@ -106,9 +107,9 @@ pub struct FATInode {
parent: Weak<LockedFATInode>,
/// 指向自身的弱引用
self_ref: Weak<LockedFATInode>,
/// 子Inode的B树. 该数据结构用作缓存区。其中它的key表示inode的名称。
/// 子Inode的map. 该数据结构用作缓存区。其中它的key表示inode的名称。
/// 请注意由于FAT的查询过程对大小写不敏感因此我们选择让key全部是大写的方便统一操作。
children: BTreeMap<DName, Arc<LockedFATInode>>,
children: HashMap<String, Arc<LockedFATInode>>,
/// 当前inode的元数据
metadata: Metadata,
/// 指向inode所在的文件系统对象的指针
@ -148,24 +149,25 @@ impl FATInode {
fn find(&mut self, name: &str) -> Result<Arc<LockedFATInode>, SystemError> {
match &self.inode_type {
FATDirEntry::Dir(d) => {
let dname = DName::from(name.to_uppercase());
let search_name = to_search_name(name);
// 尝试在缓存区查找
if let Some(entry) = self.children.get(&dname) {
if let Some(entry) = self.children.get(&search_name) {
return Ok(entry.clone());
}
// 在缓存区找不到
// 在磁盘查找
let fat_entry: FATDirEntry =
d.find_entry(name, None, None, self.fs.upgrade().unwrap())?;
let dname = DName::from(name);
// 创建新的inode
let entry_inode: Arc<LockedFATInode> = LockedFATInode::new(
dname.clone(),
dname,
self.fs.upgrade().unwrap(),
self.self_ref.clone(),
fat_entry,
);
// 加入缓存区, 由于FAT文件系统的大小写不敏感问题因此存入缓存区的key应当是全大写的
self.children.insert(dname, entry_inode.clone());
self.children.insert(search_name, entry_inode.clone());
return Ok(entry_inode);
}
FATDirEntry::UnInit => {
@ -197,7 +199,7 @@ impl LockedFATInode {
let inode: Arc<LockedFATInode> = Arc::new(LockedFATInode(SpinLock::new(FATInode {
parent,
self_ref: Weak::default(),
children: BTreeMap::new(),
children: HashMap::new(),
fs: Arc::downgrade(&fs),
inode_type,
metadata: Metadata {
@ -348,7 +350,7 @@ impl FATFileSystem {
let root_inode: Arc<LockedFATInode> = Arc::new(LockedFATInode(SpinLock::new(FATInode {
parent: Weak::default(),
self_ref: Weak::default(),
children: BTreeMap::new(),
children: HashMap::new(),
fs: Weak::default(),
inode_type: FATDirEntry::UnInit,
metadata: Metadata {
@ -1559,14 +1561,15 @@ impl IndexNode for LockedFATInode {
for ent in dir_iter {
ret.push(ent.name());
// ====== 生成inode缓存存入B树
let name = DName::from(ent.name().to_uppercase());
// ====== 生成inode缓存
let search_name = to_search_name_string(ent.name());
// debug!("name={name}");
if !guard.children.contains_key(&name)
&& name.as_ref() != "."
&& name.as_ref() != ".."
if !guard.children.contains_key(&search_name)
&& search_name != "."
&& search_name != ".."
{
let name = DName::from(ent.name());
// 创建新的inode
let entry_inode: Arc<LockedFATInode> = LockedFATInode::new(
name.clone(),
@ -1575,7 +1578,7 @@ impl IndexNode for LockedFATInode {
ent,
);
// 加入缓存区, 由于FAT文件系统的大小写不敏感问题因此存入缓存区的key应当是全大写的
guard.children.insert(name, entry_inode.clone());
guard.children.insert(search_name, entry_inode.clone());
}
}
return Ok(ret);
@ -1611,7 +1614,7 @@ impl IndexNode for LockedFATInode {
// 对目标inode上锁以防更改
let target_guard: SpinLockGuard<FATInode> = target.0.lock();
// 先从缓存删除
let nod = guard.children.remove(&DName::from(name.to_uppercase()));
let nod = guard.children.remove(&to_search_name(name));
// 若删除缓存中为管道的文件,则不需要再到磁盘删除
if nod.is_some() {
@ -1646,7 +1649,7 @@ impl IndexNode for LockedFATInode {
// 对目标inode上锁以防更改
let target_guard: SpinLockGuard<FATInode> = target.0.lock();
// 先从缓存删除
guard.children.remove(&DName::from(name.to_uppercase()));
guard.children.remove(&to_search_name(name));
let dir = match &guard.inode_type {
FATDirEntry::File(_) | FATDirEntry::VolId(_) => {
@ -1669,9 +1672,7 @@ impl IndexNode for LockedFATInode {
Err(r) => {
if r == SystemError::ENOTEMPTY {
// 如果要删除的是目录,且不为空,则删除动作未发生,重新加入缓存
guard
.children
.insert(DName::from(name.to_uppercase()), target.clone());
guard.children.insert(to_search_name(name), target.clone());
drop(target_guard);
}
return Err(r);
@ -1695,7 +1696,6 @@ impl IndexNode for LockedFATInode {
let old_inode_guard: SpinLockGuard<FATInode> = old_inode.0.lock();
let fs = old_inode_guard.fs.upgrade().unwrap();
// 从缓存删除
let _nod = guard.children.remove(&DName::from(old_name.to_uppercase()));
let old_dir = match &guard.inode_type {
FATDirEntry::File(_) | FATDirEntry::VolId(_) => {
return Err(SystemError::ENOTDIR);
@ -1710,6 +1710,7 @@ impl IndexNode for LockedFATInode {
// old_dir.check_existence(old_name, Some(false), guard.fs.upgrade().unwrap())?;
old_dir.rename(fs, old_name, new_name)?;
let _nod = guard.children.remove(&to_search_name(old_name));
} else {
let mut old_guard = self.0.lock();
let other: &LockedFATInode = target
@ -1721,10 +1722,7 @@ impl IndexNode for LockedFATInode {
// 对目标inode上锁以防更改
let old_inode_guard: SpinLockGuard<FATInode> = old_inode.0.lock();
let fs = old_inode_guard.fs.upgrade().unwrap();
// 从缓存删除
let _nod = old_guard
.children
.remove(&DName::from(old_name.to_uppercase()));
let old_dir = match &old_guard.inode_type {
FATDirEntry::File(_) | FATDirEntry::VolId(_) => {
return Err(SystemError::ENOTDIR);
@ -1748,6 +1746,8 @@ impl IndexNode for LockedFATInode {
// 检查文件是否存在
old_dir.check_existence(old_name, Some(false), old_guard.fs.upgrade().unwrap())?;
old_dir.rename_across(fs, new_dir, old_name, new_name)?;
// 从缓存删除
let _nod = old_guard.children.remove(&to_search_name(old_name));
}
return Ok(());
@ -1806,9 +1806,9 @@ impl IndexNode for LockedFATInode {
return self.create(filename, FileType::File, mode);
}
let filename = DName::from(filename.to_uppercase());
let dname = DName::from(filename);
let nod = LockedFATInode::new(
filename.clone(),
dname,
inode.fs.upgrade().unwrap(),
inode.self_ref.clone(),
FATDirEntry::File(FATFile::default()),
@ -1830,7 +1830,7 @@ impl IndexNode for LockedFATInode {
return Err(SystemError::EINVAL);
}
inode.children.insert(filename, nod.clone());
inode.children.insert(to_search_name(filename), nod.clone());
Ok(nod)
}

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@ -1,3 +1,4 @@
use alloc::string::String;
use core::char::REPLACEMENT_CHARACTER;
/// FAT文件系统保留开头的2个簇
@ -5,7 +6,7 @@ pub const RESERVED_CLUSTERS: u32 = 2;
/// @brief 将u8转为ascii字符。
/// 当转码成功时返回对应的ascii字符否则返回Unicode占位符
pub fn decode_u8_ascii(value: u8) -> char {
pub(super) fn decode_u8_ascii(value: u8) -> char {
if value <= 0x7f {
return value as char;
} else {
@ -13,3 +14,16 @@ pub fn decode_u8_ascii(value: u8) -> char {
return REPLACEMENT_CHARACTER;
}
}
/// 把名称转为inode缓存里面的key
#[inline(always)]
pub(super) fn to_search_name(name: &str) -> String {
name.to_ascii_uppercase()
}
/// 把名称转为inode缓存里面的key(输入为string原地替换)
#[inline(always)]
pub(super) fn to_search_name_string(mut name: String) -> String {
name.make_ascii_uppercase();
name
}

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@ -12,9 +12,13 @@ use crate::{
procfs::procfs_init,
ramfs::RamFS,
sysfs::sysfs_init,
vfs::{mount::MountFS, syscall::ModeType, AtomicInodeId, FileSystem, FileType},
vfs::{
mount::MountFS, syscall::ModeType, AtomicInodeId, FileSystem, FileType, MAX_PATHLEN,
},
},
libs::spinlock::SpinLock,
process::ProcessManager,
syscall::user_access::check_and_clone_cstr,
};
use super::{
@ -23,7 +27,7 @@ use super::{
mount::{init_mountlist, MOUNT_LIST},
syscall::UmountFlag,
utils::{rsplit_path, user_path_at},
IndexNode, InodeId, VFS_MAX_FOLLOW_SYMLINK_TIMES,
FilePrivateData, IndexNode, InodeId, VFS_MAX_FOLLOW_SYMLINK_TIMES,
};
/// 当没有指定根文件系统时,尝试的根文件系统列表
@ -248,6 +252,48 @@ pub fn do_unlink_at(dirfd: i32, path: &str) -> Result<u64, SystemError> {
return Ok(0);
}
pub fn do_symlinkat(from: *const u8, newdfd: i32, to: *const u8) -> Result<usize, SystemError> {
let oldname = check_and_clone_cstr(from, Some(MAX_PATHLEN))?
.into_string()
.map_err(|_| SystemError::EINVAL)?;
let newname = check_and_clone_cstr(to, Some(MAX_PATHLEN))?
.into_string()
.map_err(|_| SystemError::EINVAL)?;
let from = oldname.as_str().trim();
let to = newname.as_str().trim();
// TODO: 添加权限检查,确保进程拥有目标路径的权限
let pcb = ProcessManager::current_pcb();
let (old_begin_inode, old_remain_path) = user_path_at(&pcb, AtFlags::AT_FDCWD.bits(), from)?;
// info!("old_begin_inode={:?}", old_begin_inode.metadata());
let _ =
old_begin_inode.lookup_follow_symlink(&old_remain_path, VFS_MAX_FOLLOW_SYMLINK_TIMES)?;
// 得到新创建节点的父节点
let (new_begin_inode, new_remain_path) = user_path_at(&pcb, newdfd, to)?;
let (new_name, new_parent_path) = rsplit_path(&new_remain_path);
let new_parent = new_begin_inode
.lookup_follow_symlink(new_parent_path.unwrap_or("/"), VFS_MAX_FOLLOW_SYMLINK_TIMES)?;
// info!("new_parent={:?}", new_parent.metadata());
if new_parent.metadata()?.file_type != FileType::Dir {
return Err(SystemError::ENOTDIR);
}
let new_inode = new_parent.create_with_data(
new_name,
FileType::SymLink,
ModeType::from_bits_truncate(0o777),
0,
)?;
let buf = old_remain_path.as_bytes();
let len = buf.len();
new_inode.write_at(0, len, buf, SpinLock::new(FilePrivateData::Unused).lock())?;
return Ok(0);
}
/// # do_mount - 挂载文件系统
///
/// 将给定的文件系统挂载到指定的挂载点。

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@ -8,6 +8,7 @@ use alloc::{
collections::BTreeMap,
string::{String, ToString},
sync::{Arc, Weak},
vec::Vec,
};
use system_error::SystemError;
@ -215,12 +216,29 @@ impl MountFSInode {
.ok_or(SystemError::ENOENT);
}
fn do_absolute_path(&self, len: usize) -> Result<String, SystemError> {
if self.metadata()?.inode_id == ROOT_INODE().metadata()?.inode_id {
return Ok(String::with_capacity(len));
fn do_absolute_path(&self) -> Result<String, SystemError> {
let mut path_parts = Vec::new();
let mut current = self.self_ref.upgrade().unwrap();
while current.metadata()?.inode_id != ROOT_INODE().metadata()?.inode_id {
let name = current.dname()?;
path_parts.push(name.0);
current = current.do_parent()?;
}
let name = self.dname()?;
return Ok(self.do_parent()?.do_absolute_path(len + name.0.len() + 1)? + "/" + &name.0);
// 由于我们从叶子节点向上遍历到根节点,所以需要反转路径部分
path_parts.reverse();
// 构建最终的绝对路径字符串
let mut absolute_path = String::with_capacity(
path_parts.iter().map(|s| s.len()).sum::<usize>() + path_parts.len(),
);
for part in path_parts {
absolute_path.push('/');
absolute_path.push_str(&part);
}
Ok(absolute_path)
}
}
@ -469,7 +487,7 @@ impl IndexNode for MountFSInode {
}
fn absolute_path(&self) -> Result<String, SystemError> {
self.do_absolute_path(0)
self.do_absolute_path()
}
#[inline]

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@ -20,6 +20,7 @@ use crate::{
time::{syscall::PosixTimeval, PosixTimeSpec},
};
use super::core::do_symlinkat;
use super::{
core::{do_mkdir_at, do_remove_dir, do_unlink_at},
fcntl::{AtFlags, FcntlCommand, FD_CLOEXEC},
@ -980,6 +981,18 @@ impl Syscall {
return do_unlink_at(AtFlags::AT_FDCWD.bits(), &path).map(|v| v as usize);
}
pub fn symlink(oldname: *const u8, newname: *const u8) -> Result<usize, SystemError> {
return do_symlinkat(oldname, AtFlags::AT_FDCWD.bits(), newname);
}
pub fn symlinkat(
oldname: *const u8,
newdfd: i32,
newname: *const u8,
) -> Result<usize, SystemError> {
return do_symlinkat(oldname, newdfd, newname);
}
/// # 修改文件名
///
///

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@ -346,6 +346,20 @@ impl Syscall {
Self::unlinkat(dirfd, path, flags)
}
#[cfg(target_arch = "x86_64")]
SYS_SYMLINK => {
let oldname = args[0] as *const u8;
let newname = args[1] as *const u8;
Self::symlink(oldname, newname)
}
SYS_SYMLINKAT => {
let oldname = args[0] as *const u8;
let newdfd = args[1] as i32;
let newname = args[2] as *const u8;
Self::symlinkat(oldname, newdfd, newname)
}
#[cfg(target_arch = "x86_64")]
SYS_RMDIR => {
let path = args[0] as *const u8;

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@ -8,4 +8,5 @@ authors = [ "xiaolin2004 <1553367438@qq.com>" ]
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
libc="0.2"
errno = "0.3.9"
libc="0.2"

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@ -1,8 +1,10 @@
use core::ffi::{c_char, c_void};
use errno::errno;
use libc::{mount, MS_BIND};
use std::fs;
use std::path::Path;
use std::time;
fn main() {
let path = Path::new("mnt/tmp");
let dir = fs::create_dir_all(path);
@ -26,7 +28,8 @@ fn main() {
if result == 0 {
println!("Mount successful");
} else {
println!("Mount failed");
let err = errno();
println!("Mount failed with error code: {}", err.0);
}
let dur = clock.elapsed();
println!("mount costing time: {} ns", dur.as_nanos());

3
user/apps/test-symlink/.gitignore vendored Normal file
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@ -0,0 +1,3 @@
/target
Cargo.lock
/install/

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@ -0,0 +1,13 @@
[package]
name = "test-symlink"
version = "0.1.0"
edition = "2021"
description = "测试symlink系统调用"
authors = [ "sparkzky <sparkhhhhhhhhh@outlook.com>" ]
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
errno = "0.3.9"
libc="0.2"
nix = "0.23"

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@ -0,0 +1,56 @@
TOOLCHAIN=
RUSTFLAGS=
ifdef DADK_CURRENT_BUILD_DIR
# 如果是在dadk中编译那么安装到dadk的安装目录中
INSTALL_DIR = $(DADK_CURRENT_BUILD_DIR)
else
# 如果是在本地编译那么安装到当前目录下的install目录中
INSTALL_DIR = ./install
endif
ifeq ($(ARCH), x86_64)
export RUST_TARGET=x86_64-unknown-linux-musl
else ifeq ($(ARCH), riscv64)
export RUST_TARGET=riscv64gc-unknown-linux-gnu
else
# 默认为x86_86用于本地编译
export RUST_TARGET=x86_64-unknown-linux-musl
endif
run:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) run --target $(RUST_TARGET)
build:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) build --target $(RUST_TARGET)
clean:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) clean --target $(RUST_TARGET)
test:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) test --target $(RUST_TARGET)
doc:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) doc --target $(RUST_TARGET)
fmt:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) fmt
fmt-check:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) fmt --check
run-release:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) run --target $(RUST_TARGET) --release
build-release:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) build --target $(RUST_TARGET) --release
clean-release:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) clean --target $(RUST_TARGET) --release
test-release:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) test --target $(RUST_TARGET) --release
.PHONY: install
install:
RUSTFLAGS=$(RUSTFLAGS) cargo $(TOOLCHAIN) install --target $(RUST_TARGET) --path . --no-track --root $(INSTALL_DIR) --force

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@ -0,0 +1 @@
# 测试Symlink系统调用的程序

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@ -0,0 +1,78 @@
extern crate libc;
use core::ffi::{c_char, c_void};
use libc::{mount, umount};
use nix::errno::Errno;
use std::fs;
use std::os::unix::fs::symlink;
use std::path::Path;
fn main() {
mount_test_ramfs();
let target = "/mnt/myramfs/target_file.txt";
let symlink_path = "/mnt/myramfs/another/symlink_file.txt";
let dir = "/mnt/myramfs/another";
fs::write(target, "This is the content of the target file.")
.expect("Failed to create target file");
fs::create_dir(dir).expect("Failed to create target dir");
assert!(Path::new(target).exists(), "Target file was not created");
assert!(Path::new(dir).exists(), "Target dir was not created");
symlink(target, symlink_path).expect("Failed to create symlink");
assert!(Path::new(symlink_path).exists(), "Symlink was not created");
let symlink_content = fs::read_link(symlink_path).expect("Failed to read symlink");
assert_eq!(
symlink_content.display().to_string(),
target,
"Symlink points to the wrong target"
);
fs::remove_file(symlink_path).expect("Failed to remove symlink");
fs::remove_file(target).expect("Failed to remove target file");
fs::remove_dir(dir).expect("Failed to remove test_dir");
assert!(!Path::new(symlink_path).exists(), "Symlink was not deleted");
assert!(!Path::new(target).exists(), "Target file was not deleted");
assert!(!Path::new(dir).exists(), "Directory was not deleted");
umount_test_ramfs();
println!("All tests passed!");
}
fn mount_test_ramfs() {
let path = Path::new("mnt/myramfs");
let dir = fs::create_dir_all(path);
assert!(dir.is_ok(), "mkdir /mnt/myramfs failed");
let source = b"\0".as_ptr() as *const c_char;
let target = b"/mnt/myramfs\0".as_ptr() as *const c_char;
let fstype = b"ramfs\0".as_ptr() as *const c_char;
// let flags = MS_BIND;
let flags = 0;
let data = std::ptr::null() as *const c_void;
let result = unsafe { mount(source, target, fstype, flags, data) };
assert_eq!(
result,
0,
"Mount myramfs failed, errno: {}",
Errno::last().desc()
);
println!("Mount myramfs success!");
}
fn umount_test_ramfs() {
let path = b"/mnt/myramfs\0".as_ptr() as *const c_char;
let result = unsafe { umount(path) };
if result != 0 {
let err = Errno::last();
println!("Errno: {}", err);
println!("Infomation: {}", err.desc());
}
assert_eq!(result, 0, "Umount myramfs failed");
}

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@ -0,0 +1,29 @@
{
"name": "test-symlink",
"version": "0.1.0",
"description": "测试symlink系统调用",
"rust_target": "x86_64-unknown-dragonos",
"task_type": {
"BuildFromSource": {
"Local": {
"path": "apps/test-symlink"
}
}
},
"depends": [],
"build": {
"build_command": "make install"
},
"install": {
"in_dragonos_path": "/"
},
"clean": {
"clean_command": "make clean"
},
"envs": [],
"build_once": false,
"install_once": false,
"target_arch": [
"x86_64"
]
}