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Rust
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use alloc::sync::Arc;
use log::warn;
use system_error::SystemError;
use crate::{
driver::base::block::SeekFrom, process::ProcessManager,
syscall::user_access::check_and_clone_cstr,
};
use super::{
fcntl::AtFlags,
file::{File, FileMode},
syscall::{ModeType, OpenHow, OpenHowResolve},
utils::{rsplit_path, user_path_at},
FileType, IndexNode, MAX_PATHLEN, ROOT_INODE, VFS_MAX_FOLLOW_SYMLINK_TIMES,
};
pub(super) fn do_faccessat(
dirfd: i32,
path: *const u8,
mode: ModeType,
flags: u32,
) -> Result<usize, SystemError> {
if (mode.bits() & (!ModeType::S_IRWXO.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;
let path = check_and_clone_cstr(path, Some(MAX_PATHLEN))?;
let (inode, path) = user_path_at(&ProcessManager::current_pcb(), dirfd, &path)?;
// 如果找不到文件则返回错误码ENOENT
let _inode = inode.lookup_follow_symlink(path.as_str(), VFS_MAX_FOLLOW_SYMLINK_TIMES)?;
// todo: 接着完善可以借鉴linux 6.1.9的do_faccessat
return Ok(0);
}
pub fn do_fchmodat(dirfd: i32, path: *const u8, _mode: ModeType) -> Result<usize, SystemError> {
let path = check_and_clone_cstr(path, Some(MAX_PATHLEN))?;
let (inode, path) = user_path_at(&ProcessManager::current_pcb(), dirfd, &path)?;
// 如果找不到文件则返回错误码ENOENT
let _inode = inode.lookup_follow_symlink(path.as_str(), VFS_MAX_FOLLOW_SYMLINK_TIMES)?;
warn!("do_fchmodat: not implemented yet\n");
// todo: 真正去改变文件的权限
return Ok(0);
}
pub(super) fn do_sys_open(
dfd: i32,
path: &str,
o_flags: FileMode,
mode: ModeType,
follow_symlink: bool,
) -> Result<usize, SystemError> {
let how = OpenHow::new(o_flags, mode, OpenHowResolve::empty());
return do_sys_openat2(dfd, path, how, follow_symlink);
}
fn do_sys_openat2(
dirfd: i32,
path: &str,
how: OpenHow,
follow_symlink: bool,
) -> Result<usize, SystemError> {
// debug!("open path: {}, how: {:?}", path, how);
let path = path.trim();
let (inode_begin, path) = user_path_at(&ProcessManager::current_pcb(), dirfd, path)?;
let inode: Result<Arc<dyn IndexNode>, SystemError> = inode_begin.lookup_follow_symlink(
&path,
if follow_symlink {
VFS_MAX_FOLLOW_SYMLINK_TIMES
} else {
0
},
);
let inode: Arc<dyn IndexNode> = match inode {
Ok(inode) => inode,
Err(errno) => {
// 文件不存在,且需要创建
if how.o_flags.contains(FileMode::O_CREAT)
&& !how.o_flags.contains(FileMode::O_DIRECTORY)
&& errno == SystemError::ENOENT
{
let (filename, parent_path) = rsplit_path(&path);
// 查找父目录
let parent_inode: Arc<dyn IndexNode> =
ROOT_INODE().lookup(parent_path.unwrap_or("/"))?;
// 创建文件
let inode: Arc<dyn IndexNode> = parent_inode.create(
filename,
FileType::File,
ModeType::from_bits_truncate(0o755),
)?;
inode
} else {
// 不需要创建文件,因此返回错误码
return Err(errno);
}
}
};
let file_type: FileType = inode.metadata()?.file_type;
// 如果要打开的是文件夹,而目标不是文件夹
if how.o_flags.contains(FileMode::O_DIRECTORY) && file_type != FileType::Dir {
return Err(SystemError::ENOTDIR);
}
// 创建文件对象
let file: File = File::new(inode, how.o_flags)?;
// 打开模式为“追加”
if how.o_flags.contains(FileMode::O_APPEND) {
file.lseek(SeekFrom::SeekEnd(0))?;
}
// 如果O_TRUNC并且打开模式包含O_RDWR或O_WRONLY清空文件
if how.o_flags.contains(FileMode::O_TRUNC)
&& (how.o_flags.contains(FileMode::O_RDWR) || how.o_flags.contains(FileMode::O_WRONLY))
&& file_type == FileType::File
{
file.ftruncate(0)?;
}
// 把文件对象存入pcb
let r = ProcessManager::current_pcb()
.fd_table()
.write()
.alloc_fd(file, None)
.map(|fd| fd as usize);
return r;
}