Jeremy Soller
480 lines
16 KiB
Rust
480 lines
16 KiB
Rust
//! Filesystem syscalls
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use core::sync::atomic::Ordering;
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use alloc::arc::Arc;
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use spin::RwLock;
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use context;
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use scheme::{self, FileHandle};
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use syscall;
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use syscall::data::{Packet, Stat};
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use syscall::error::*;
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use syscall::flag::{F_GETFD, F_SETFD, F_GETFL, F_SETFL, F_DUPFD, O_ACCMODE, O_DIRECTORY, O_RDONLY, O_WRONLY, MODE_DIR, MODE_FILE, O_CLOEXEC};
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use context::file::{FileDescriptor, FileDescription};
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pub fn file_op(a: usize, fd: FileHandle, c: usize, d: usize) -> Result<usize> {
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let (file, pid, uid, gid) = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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let file = context.get_file(fd).ok_or(Error::new(EBADF))?;
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(file, context.id, context.euid, context.egid)
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};
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let scheme = {
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let schemes = scheme::schemes();
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let scheme = schemes.get(file.description.read().scheme).ok_or(Error::new(EBADF))?;
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Arc::clone(&scheme)
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};
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let mut packet = Packet {
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id: 0,
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pid: pid.into(),
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uid: uid,
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gid: gid,
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a: a,
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b: file.description.read().number,
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c: c,
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d: d
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};
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scheme.handle(&mut packet);
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Error::demux(packet.a)
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}
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pub fn file_op_slice(a: usize, fd: FileHandle, slice: &[u8]) -> Result<usize> {
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file_op(a, fd, slice.as_ptr() as usize, slice.len())
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}
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pub fn file_op_mut_slice(a: usize, fd: FileHandle, slice: &mut [u8]) -> Result<usize> {
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file_op(a, fd, slice.as_mut_ptr() as usize, slice.len())
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}
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/// Change the current working directory
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pub fn chdir(path: &[u8]) -> Result<usize> {
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let fd = open(path, O_RDONLY | O_DIRECTORY)?;
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let mut stat = Stat::default();
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let stat_res = file_op_mut_slice(syscall::number::SYS_FSTAT, fd, &mut stat);
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let _ = close(fd);
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stat_res?;
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if stat.st_mode & (MODE_FILE | MODE_DIR) == MODE_DIR {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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let canonical = context.canonicalize(path);
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*context.cwd.lock() = canonical;
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Ok(0)
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} else {
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Err(Error::new(ENOTDIR))
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}
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}
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/// Get the current working directory
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pub fn getcwd(buf: &mut [u8]) -> Result<usize> {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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let cwd = context.cwd.lock();
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let mut i = 0;
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while i < buf.len() && i < cwd.len() {
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buf[i] = cwd[i];
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i += 1;
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}
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Ok(i)
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}
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/// Open syscall
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pub fn open(path: &[u8], flags: usize) -> Result<FileHandle> {
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let (path_canon, uid, gid, scheme_ns) = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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(context.canonicalize(path), context.euid, context.egid, context.ens)
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};
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//println!("open {}", unsafe { ::core::str::from_utf8_unchecked(&path_canon) });
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let mut parts = path_canon.splitn(2, |&b| b == b':');
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let scheme_name_opt = parts.next();
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let reference_opt = parts.next();
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let (scheme_id, file_id) = {
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let scheme_name = scheme_name_opt.ok_or(Error::new(ENODEV))?;
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let (scheme_id, scheme) = {
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let schemes = scheme::schemes();
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let (scheme_id, scheme) = schemes.get_name(scheme_ns, scheme_name).ok_or(Error::new(ENODEV))?;
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(scheme_id, Arc::clone(&scheme))
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};
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let file_id = scheme.open(reference_opt.unwrap_or(b""), flags, uid, gid)?;
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(scheme_id, file_id)
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};
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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context.add_file(FileDescriptor {
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description: Arc::new(RwLock::new(FileDescription {
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scheme: scheme_id,
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number: file_id,
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flags: flags & !O_CLOEXEC,
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})),
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event: None,
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cloexec: flags & O_CLOEXEC == O_CLOEXEC,
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}).ok_or(Error::new(EMFILE))
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}
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pub fn pipe2(fds: &mut [usize], flags: usize) -> Result<usize> {
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if fds.len() >= 2 {
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let scheme_id = ::scheme::pipe::PIPE_SCHEME_ID.load(Ordering::SeqCst);
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let (read_id, write_id) = ::scheme::pipe::pipe(flags);
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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let read_fd = context.add_file(FileDescriptor {
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description: Arc::new(RwLock::new(FileDescription {
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scheme: scheme_id,
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number: read_id,
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flags: O_RDONLY | flags & !O_ACCMODE & !O_CLOEXEC,
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})),
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event: None,
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cloexec: flags & O_CLOEXEC == O_CLOEXEC,
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}).ok_or(Error::new(EMFILE))?;
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let write_fd = context.add_file(FileDescriptor {
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description: Arc::new(RwLock::new(FileDescription {
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scheme: scheme_id,
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number: write_id,
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flags: O_WRONLY | flags & !O_ACCMODE & !O_CLOEXEC,
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})),
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event: None,
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cloexec: flags & O_CLOEXEC == O_CLOEXEC,
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}).ok_or(Error::new(EMFILE))?;
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fds[0] = read_fd.into();
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fds[1] = write_fd.into();
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Ok(0)
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} else {
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Err(Error::new(EFAULT))
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}
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}
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/// chmod syscall
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pub fn chmod(path: &[u8], mode: u16) -> Result<usize> {
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let (path_canon, uid, gid, scheme_ns) = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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(context.canonicalize(path), context.euid, context.egid, context.ens)
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};
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let mut parts = path_canon.splitn(2, |&b| b == b':');
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let scheme_name_opt = parts.next();
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let reference_opt = parts.next();
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let scheme_name = scheme_name_opt.ok_or(Error::new(ENODEV))?;
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let scheme = {
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let schemes = scheme::schemes();
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let (_scheme_id, scheme) = schemes.get_name(scheme_ns, scheme_name).ok_or(Error::new(ENODEV))?;
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Arc::clone(&scheme)
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};
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scheme.chmod(reference_opt.unwrap_or(b""), mode, uid, gid)
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}
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/// rmdir syscall
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pub fn rmdir(path: &[u8]) -> Result<usize> {
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let (path_canon, uid, gid, scheme_ns) = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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(context.canonicalize(path), context.euid, context.egid, context.ens)
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};
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let mut parts = path_canon.splitn(2, |&b| b == b':');
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let scheme_name_opt = parts.next();
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let reference_opt = parts.next();
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let scheme_name = scheme_name_opt.ok_or(Error::new(ENODEV))?;
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let scheme = {
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let schemes = scheme::schemes();
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let (_scheme_id, scheme) = schemes.get_name(scheme_ns, scheme_name).ok_or(Error::new(ENODEV))?;
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Arc::clone(&scheme)
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};
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scheme.rmdir(reference_opt.unwrap_or(b""), uid, gid)
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}
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/// Unlink syscall
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pub fn unlink(path: &[u8]) -> Result<usize> {
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let (path_canon, uid, gid, scheme_ns) = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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(context.canonicalize(path), context.euid, context.egid, context.ens)
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};
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let mut parts = path_canon.splitn(2, |&b| b == b':');
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let scheme_name_opt = parts.next();
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let reference_opt = parts.next();
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let scheme_name = scheme_name_opt.ok_or(Error::new(ENODEV))?;
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let scheme = {
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let schemes = scheme::schemes();
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let (_scheme_id, scheme) = schemes.get_name(scheme_ns, scheme_name).ok_or(Error::new(ENODEV))?;
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Arc::clone(&scheme)
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};
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scheme.unlink(reference_opt.unwrap_or(b""), uid, gid)
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}
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/// Close syscall
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pub fn close(fd: FileHandle) -> Result<usize> {
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let file = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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context.remove_file(fd).ok_or(Error::new(EBADF))?
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};
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file.close(fd)
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}
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fn duplicate_file(fd: FileHandle, buf: &[u8]) -> Result<FileDescriptor> {
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let file = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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context.get_file(fd).ok_or(Error::new(EBADF))?
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};
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if buf.is_empty() {
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Ok(FileDescriptor {
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description: Arc::clone(&file.description),
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event: None,
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cloexec: false,
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})
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} else {
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let description = file.description.read();
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let new_id = {
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let scheme = {
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let schemes = scheme::schemes();
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let scheme = schemes.get(description.scheme).ok_or(Error::new(EBADF))?;
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Arc::clone(&scheme)
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};
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scheme.dup(description.number, buf)?
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};
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Ok(FileDescriptor {
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description: Arc::new(RwLock::new(FileDescription {
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scheme: description.scheme,
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number: new_id,
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flags: description.flags,
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})),
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event: None,
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cloexec: false,
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})
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}
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}
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/// Duplicate file descriptor
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pub fn dup(fd: FileHandle, buf: &[u8]) -> Result<FileHandle> {
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let new_file = duplicate_file(fd, buf)?;
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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context.add_file(new_file).ok_or(Error::new(EMFILE))
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}
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/// Duplicate file descriptor, replacing another
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pub fn dup2(fd: FileHandle, new_fd: FileHandle, buf: &[u8]) -> Result<FileHandle> {
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if fd == new_fd {
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Ok(new_fd)
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} else {
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let _ = close(new_fd);
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let new_file = duplicate_file(fd, buf)?;
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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context.insert_file(new_fd, new_file).ok_or(Error::new(EMFILE))
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}
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}
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/// File descriptor controls
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pub fn fcntl(fd: FileHandle, cmd: usize, arg: usize) -> Result<usize> {
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let file = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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context.get_file(fd).ok_or(Error::new(EBADF))?
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};
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let description = file.description.read();
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// Communicate fcntl with scheme
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if cmd != F_DUPFD && cmd != F_GETFD && cmd != F_SETFD {
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let scheme = {
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let schemes = scheme::schemes();
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let scheme = schemes.get(description.scheme).ok_or(Error::new(EBADF))?;
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Arc::clone(&scheme)
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};
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scheme.fcntl(description.number, cmd, arg)?;
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};
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// Perform kernel operation if scheme agrees
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{
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if cmd == F_DUPFD {
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// Not in match because 'files' cannot be locked
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let new_file = duplicate_file(fd, &[])?;
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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return context.add_file_min(new_file, arg)
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.ok_or(Error::new(EMFILE))
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.map(FileHandle::into);
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}
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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let mut files = context.files.lock();
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match *files.get_mut(fd.into()).ok_or(Error::new(EBADF))? {
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Some(ref mut file) => match cmd {
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F_GETFD => {
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if file.cloexec {
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Ok(O_CLOEXEC)
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} else {
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Ok(0)
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}
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},
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F_SETFD => {
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file.cloexec = arg & O_CLOEXEC == O_CLOEXEC;
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Ok(0)
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},
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F_GETFL => {
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Ok(description.flags)
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},
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F_SETFL => {
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let new_flags = (description.flags & O_ACCMODE) | (arg & ! O_ACCMODE);
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drop(description);
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file.description.write().flags = new_flags;
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Ok(0)
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},
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_ => {
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Err(Error::new(EINVAL))
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}
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},
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None => Err(Error::new(EBADF))
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}
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}
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}
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/// Register events for file
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pub fn fevent(fd: FileHandle, flags: usize) -> Result<usize> {
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let file = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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let mut files = context.files.lock();
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match *files.get_mut(fd.into()).ok_or(Error::new(EBADF))? {
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Some(ref mut file) => {
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let description = file.description.read();
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if let Some(event_id) = file.event.take() {
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println!("{:?}: {:?}:{}: events already registered: {}", fd, description.scheme, description.number, event_id);
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context::event::unregister(fd, description.scheme, event_id);
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}
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file.clone()
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},
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None => return Err(Error::new(EBADF))
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}
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};
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let description = file.description.read();
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let scheme = {
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let schemes = scheme::schemes();
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let scheme = schemes.get(description.scheme).ok_or(Error::new(EBADF))?;
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Arc::clone(&scheme)
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};
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let event_id = scheme.fevent(description.number, flags)?;
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{
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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let mut files = context.files.lock();
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match *files.get_mut(fd.into()).ok_or(Error::new(EBADF))? {
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Some(ref mut file) => file.event = Some(event_id),
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None => return Err(Error::new(EBADF)),
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}
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}
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context::event::register(fd, description.scheme, event_id);
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Ok(0)
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}
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pub fn frename(fd: FileHandle, path: &[u8]) -> Result<usize> {
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let file = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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let file = context.get_file(fd).ok_or(Error::new(EBADF))?;
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file
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};
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let (path_canon, uid, gid, scheme_ns) = {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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(context.canonicalize(path), context.euid, context.egid, context.ens)
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};
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let mut parts = path_canon.splitn(2, |&b| b == b':');
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let scheme_name_opt = parts.next();
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let reference_opt = parts.next();
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let scheme_name = scheme_name_opt.ok_or(Error::new(ENODEV))?;
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let (scheme_id, scheme) = {
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let schemes = scheme::schemes();
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let (scheme_id, scheme) = schemes.get_name(scheme_ns, scheme_name).ok_or(Error::new(ENODEV))?;
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(scheme_id, scheme.clone())
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};
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let description = file.description.read();
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if scheme_id == description.scheme {
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scheme.frename(description.number, reference_opt.unwrap_or(b""), uid, gid)
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} else {
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Err(Error::new(EXDEV))
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}
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}
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pub fn funmap(virtual_address: usize) -> Result<usize> {
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if virtual_address == 0 {
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Ok(0)
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} else {
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let contexts = context::contexts();
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let context_lock = contexts.current().ok_or(Error::new(ESRCH))?;
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let context = context_lock.read();
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let mut grants = context.grants.lock();
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for i in 0 .. grants.len() {
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let start = grants[i].start_address().get();
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let end = start + grants[i].size();
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if virtual_address >= start && virtual_address < end {
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grants.remove(i).unmap();
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return Ok(0);
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}
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}
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Err(Error::new(EFAULT))
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}
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}
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