jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include <Kernel/Debug.h>
8#include <Kernel/FileSystem/OpenFileDescription.h>
9#include <Kernel/Process.h>
10
11namespace Kernel {
12
13ErrorOr<FlatPtr> Process::sys$fcntl(int fd, int cmd, uintptr_t arg)
14{
15 VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
16 TRY(require_promise(Pledge::stdio));
17 dbgln_if(IO_DEBUG, "sys$fcntl: fd={}, cmd={}, arg={}", fd, cmd, arg);
18 auto description = TRY(open_file_description(fd));
19 // NOTE: The FD flags are not shared between OpenFileDescription objects.
20 // This means that dup() doesn't copy the FD_CLOEXEC flag!
21 switch (cmd) {
22 case F_DUPFD_CLOEXEC:
23 case F_DUPFD: {
24 int arg_fd = (int)arg;
25 if (arg_fd < 0)
26 return EINVAL;
27 return m_fds.with_exclusive([&](auto& fds) -> ErrorOr<FlatPtr> {
28 auto fd_allocation = TRY(fds.allocate(arg_fd));
29 fds[fd_allocation.fd].set(*description, (cmd == F_DUPFD_CLOEXEC) ? FD_CLOEXEC : 0);
30 return fd_allocation.fd;
31 });
32 }
33 case F_GETFD:
34 return m_fds.with_exclusive([fd](auto& fds) { return fds[fd].flags(); });
35 case F_SETFD:
36 m_fds.with_exclusive([fd, arg](auto& fds) { fds[fd].set_flags(arg); });
37 break;
38 case F_GETFL:
39 return description->file_flags();
40 case F_SETFL:
41 description->set_file_flags(arg);
42 break;
43 case F_ISTTY:
44 return description->is_tty();
45 case F_GETLK:
46 TRY(description->get_flock(Userspace<flock*>(arg)));
47 return 0;
48 case F_SETLK:
49 TRY(description->apply_flock(Process::current(), Userspace<flock const*>(arg), ShouldBlock::No));
50 return 0;
51 case F_SETLKW:
52 TRY(description->apply_flock(Process::current(), Userspace<flock const*>(arg), ShouldBlock::Yes));
53 return 0;
54 default:
55 return EINVAL;
56 }
57 return 0;
58}
59
60}