DragonOS-Community/DragonOS
1
1
Fork 0
mirror of https://github.com/DragonOS-Community/DragonOS.git synced 2025-06-10 08:06:48 +00:00
Code Issues Releases Wiki Activity

添加access、faccessat、faccessat2 (#439)

Browse Source
This commit is contained in:
LoGin 2023-11-12 21:23:48 +08:00 committed by GitHub
parent 0d9b7d9240
commit 9b0abe6da7
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
7 changed files with 164 additions and 79 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
kernel/src/arch/x86_64/syscall.rs
View File

@ -13,7 +13,10 @@ use alloc::string::String;
use super::{interrupt::TrapFrame, mm::barrier::mfence};
pub const SYS_ACCESS: usize = 21;
pub const SYS_PRLIMIT64: usize = 302;
pub const SYS_FACCESSAT: usize = 269;
pub const SYS_FACCESSAT2: usize = 439;
/// ### 存储PCB系统调用栈以及在syscall过程中暂存用户态rsp的结构体
///

87
kernel/src/filesystem/vfs/fcntl.rs
View File

@ -58,55 +58,48 @@ pub enum FcntlCommand {
SetFileRwHint = F_LINUX_SPECIFIC_BASE + 14,
}
/// The constants AT_REMOVEDIR and AT_EACCESS have the same value. AT_EACCESS is
/// meaningful only to faccessat, while AT_REMOVEDIR is meaningful only to
/// unlinkat. The two functions do completely different things and therefore,
/// the flags can be allowed to overlap. For example, passing AT_REMOVEDIR to
/// faccessat would be undefined behavior and thus treating it equivalent to
/// AT_EACCESS is valid undefined behavior.
#[derive(Debug, Copy, Clone, Eq, PartialEq, FromPrimitive, ToPrimitive)]
#[allow(non_camel_case_types)]
pub enum AtFlags {
/// 特殊值，用于指示openat应使用当前工作目录。
AtFdCwd = -100,
/// 不要跟随符号链接。
/// AT_SYMLINK_NOFOLLOW: 0x100
AtSymlinkNoFollow = 0x100,
/// AtEAccess: 使用有效ID进行访问测试，而不是实际ID。
/// AtRemoveDir: 删除目录而不是取消链接文件。
/// AT_EACCESS: 0x200
/// AT_REMOVEDIR: 0x200
AtEAccess_OR_AtRemoveDir = 0x200,
bitflags! {
/// 跟随符号链接。
/// AT_SYMLINK_FOLLOW: 0x400
AtSymlinkFollow = 0x400,
/// 禁止终端自动挂载遍历。
/// AT_NO_AUTOMOUNT: 0x800
AtNoAutomount = 0x800,
/// 允许空的相对路径名。
/// AT_EMPTY_PATH: 0x1000
AtEmptyPath = 0x1000,
/// statx()所需的同步类型。
/// AT_STATX_SYNC_TYPE: 0x6000
AtStatxSyncType = 0x6000,
/// 执行与stat()相同的操作。
/// AT_STATX_SYNC_AS_STAT: 0x0000
AtStatxSyncAsStat = 0x0000,
/// 强制将属性与服务器同步。
/// AT_STATX_FORCE_SYNC: 0x2000
AtStatxForceSync = 0x2000,
/// 不要将属性与服务器同步。
/// AT_STATX_DONT_SYNC: 0x4000
AtStatxDontSync = 0x4000,
/// 应用于整个子树。
/// AT_RECURSIVE: 0x8000
AtRecursive = 0x8000,
}
/// The constants AT_REMOVEDIR and AT_EACCESS have the same value. AT_EACCESS is
/// meaningful only to faccessat, while AT_REMOVEDIR is meaningful only to
/// unlinkat. The two functions do completely different things and therefore,
/// the flags can be allowed to overlap. For example, passing AT_REMOVEDIR to
/// faccessat would be undefined behavior and thus treating it equivalent to
/// AT_EACCESS is valid undefined behavior.
pub struct AtFlags: i32 {
/// 特殊值，用于指示openat应使用当前工作目录。
const AT_FDCWD = -100;
/// 不要跟随符号链接。
const AT_SYMLINK_NOFOLLOW = 0x100;
/// AtEAccess: 使用有效ID进行访问测试，而不是实际ID。
const AT_EACCESS = 0x200;
/// AtRemoveDir: 删除目录而不是取消链接文件。
const AT_REMOVEDIR = 0x200;
impl Into<i32> for AtFlags {
fn into(self) -> i32 {
self as i32
/// 跟随符号链接。
/// AT_SYMLINK_FOLLOW: 0x400
const AT_SYMLINK_FOLLOW = 0x400;
/// 禁止终端自动挂载遍历。
/// AT_NO_AUTOMOUNT: 0x800
const AT_NO_AUTOMOUNT = 0x800;
/// 允许空的相对路径名。
/// AT_EMPTY_PATH: 0x1000
const AT_EMPTY_PATH = 0x1000;
/// statx()所需的同步类型。
/// AT_STATX_SYNC_TYPE: 0x6000
const AT_STATX_SYNC_TYPE = 0x6000;
/// 执行与stat()相同的操作。
/// AT_STATX_SYNC_AS_STAT: 0x0000
const AT_STATX_SYNC_AS_STAT = 0x0000;
/// 强制将属性与服务器同步。
/// AT_STATX_FORCE_SYNC: 0x2000
const AT_STATX_FORCE_SYNC = 0x2000;
/// 不要将属性与服务器同步。
/// AT_STATX_DONT_SYNC: 0x4000
const AT_STATX_DONT_SYNC = 0x4000;
/// 应用于整个子树。
/// AT_RECURSIVE: 0x8000
const AT_RECURSIVE = 0x8000;
}
}

1
kernel/src/filesystem/vfs/mod.rs
View File

@ -4,6 +4,7 @@ pub mod core;
pub mod fcntl;
pub mod file;
pub mod mount;
pub mod open;
pub mod syscall;
mod utils;

27
kernel/src/filesystem/vfs/open.rs Normal file
View File

@ -0,0 +1,27 @@
use crate::syscall::SystemError;
use super::{fcntl::AtFlags, syscall::ModeType};
pub(super) fn do_faccessat(
_dirfd: i32,
_pathname: *const u8,
mode: ModeType,
flags: u32,
) -> Result<usize, SystemError> {
if (mode.bits() & (!ModeType::S_IXUGO.bits())) != 0 {
return Err(SystemError::EINVAL);
}
if (flags
& (!((AtFlags::AT_EACCESS | AtFlags::AT_SYMLINK_NOFOLLOW | AtFlags::AT_EMPTY_PATH).bits()
as u32)))
!= 0
{
return Err(SystemError::EINVAL);
}
// let follow_symlink = flags & AtFlags::AT_SYMLINK_NOFOLLOW.bits() as u32 == 0;
// todo: 接着完善（可以借鉴linux 6.1.9的do_faccessat）
return Ok(0);
}

54
kernel/src/filesystem/vfs/syscall.rs
View File

@ -25,7 +25,8 @@ use super::{
core::{do_mkdir, do_remove_dir, do_unlink_at},
fcntl::{AtFlags, FcntlCommand, FD_CLOEXEC},
file::{File, FileMode},
utils::rsplit_path,
open::do_faccessat,
utils::{rsplit_path, user_path_at},
Dirent, FileType, IndexNode, MAX_PATHLEN, ROOT_INODE, VFS_MAX_FOLLOW_SYMLINK_TIMES,
};
// use crate::kdebug;
@ -804,41 +805,14 @@ impl Syscall {
user_buf: *mut u8,
buf_size: usize,
) -> Result<usize, SystemError> {
let mut path = check_and_clone_cstr(path, Some(MAX_PATHLEN))?;
let path = check_and_clone_cstr(path, Some(MAX_PATHLEN))?;
let mut user_buf = UserBufferWriter::new(user_buf, buf_size, true)?;
if path.len() == 0 {
return Err(SystemError::EINVAL);
}
let mut inode = ROOT_INODE();
// 如果path不是绝对路径，则需要拼接
if path.as_bytes()[0] != b'/' {
// 如果dirfd不是AT_FDCWD，则需要检查dirfd是否是目录
if dirfd != AtFlags::AtFdCwd.into() {
let binding = ProcessManager::current_pcb().fd_table();
let fd_table_guard = binding.read();
let file = fd_table_guard
.get_file_by_fd(dirfd)
.ok_or(SystemError::EBADF)?;
// drop guard 以避免无法调度的问题
drop(fd_table_guard);
let file_guard = file.lock();
// 如果dirfd不是目录，则返回错误码ENOTDIR
if file_guard.file_type() != FileType::Dir {
return Err(SystemError::ENOTDIR);
}
inode = file_guard.inode();
} else {
let mut cwd = ProcessManager::current_pcb().basic().cwd();
cwd.push('/');
cwd.push_str(path.as_str());
path = cwd;
}
}
let (inode, path) = user_path_at(&ProcessManager::current_pcb(), dirfd, path)?;
let inode = inode.lookup(path.as_str())?;
if inode.metadata()?.file_type != FileType::SymLink {
@ -859,7 +833,25 @@ impl Syscall {
user_buf: *mut u8,
buf_size: usize,
) -> Result<usize, SystemError> {
return Self::readlink_at(AtFlags::AtFdCwd.into(), path, user_buf, buf_size);
return Self::readlink_at(AtFlags::AT_FDCWD.bits(), path, user_buf, buf_size);
}
pub fn access(pathname: *const u8, mode: u32) -> Result<usize, SystemError> {
return do_faccessat(
AtFlags::AT_FDCWD.bits(),
pathname,
ModeType::from_bits_truncate(mode),
0,
);
}
pub fn faccessat2(
dirfd: i32,
pathname: *const u8,
mode: u32,
flags: u32,
) -> Result<usize, SystemError> {
return do_faccessat(dirfd, pathname, ModeType::from_bits_truncate(mode), flags);
}
}

48
kernel/src/filesystem/vfs/utils.rs
View File

@ -1,3 +1,9 @@
use alloc::{string::String, sync::Arc};
use crate::{process::ProcessControlBlock, syscall::SystemError};
use super::{fcntl::AtFlags, FileType, IndexNode, ROOT_INODE};
/// @brief 切分路径字符串，返回最左侧那一级的目录名和剩余的部分。
///
/// 举例：对于 /123/456/789/ 本函数返回的第一个值为123, 第二个值为456/789
@ -19,3 +25,45 @@ pub fn rsplit_path(path: &str) -> (&str, Option<&str>) {
return (comp, rest_opt);
}
/// 根据dirfd和path，计算接下来开始lookup的inode和剩余的path
///
/// ## 返回值
///
/// 返回值为(需要lookup的inode, 剩余的path)
pub fn user_path_at(
pcb: &Arc<ProcessControlBlock>,
dirfd: i32,
mut path: String,
) -> Result<(Arc<dyn IndexNode>, String), SystemError> {
let mut inode = ROOT_INODE();
// 如果path不是绝对路径，则需要拼接
if path.as_bytes()[0] != b'/' {
// 如果dirfd不是AT_FDCWD，则需要检查dirfd是否是目录
if dirfd != AtFlags::AT_FDCWD.bits() {
let binding = pcb.fd_table();
let fd_table_guard = binding.read();
let file = fd_table_guard
.get_file_by_fd(dirfd)
.ok_or(SystemError::EBADF)?;
// drop guard 以避免无法调度的问题
drop(fd_table_guard);
let file_guard = file.lock();
// 如果dirfd不是目录，则返回错误码ENOTDIR
if file_guard.file_type() != FileType::Dir {
return Err(SystemError::ENOTDIR);
}
inode = file_guard.inode();
} else {
let mut cwd = pcb.basic().cwd();
cwd.push('/');
cwd.push_str(path.as_str());
path = cwd;
}
}
return Ok((inode, path));
}

23
kernel/src/syscall/mod.rs
View File

@ -4,7 +4,7 @@ use core::{
};
use crate::{
arch::syscall::SYS_PRLIMIT64,
arch::syscall::{SYS_ACCESS, SYS_FACCESSAT, SYS_FACCESSAT2, SYS_PRLIMIT64},
libs::{futex::constant::FutexFlag, rand::GRandFlags},
process::{
fork::KernelCloneArgs,
@ -1204,6 +1204,27 @@ impl Syscall {
Self::prlimit64(pid, resource, new_limit, old_limit)
}
SYS_ACCESS => {
let pathname = args[0] as *const u8;
let mode = args[1] as u32;
Self::access(pathname, mode)
}
SYS_FACCESSAT => {
let dirfd = args[0] as i32;
let pathname = args[1] as *const u8;
let mode = args[2] as u32;
Self::faccessat2(dirfd, pathname, mode, 0)
}
SYS_FACCESSAT2 => {
let dirfd = args[0] as i32;
let pathname = args[1] as *const u8;
let mode = args[2] as u32;
let flags = args[3] as u32;
Self::faccessat2(dirfd, pathname, mode, flags)
}
_ => panic!("Unsupported syscall ID: {}", syscall_num),
};
return r;