1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/NonnullRefPtr.h>
#include <AK/RefCounted.h>
#include <AK/String.h>
#include <AK/Types.h>
#include <AK/Weakable.h>
#include <Kernel/API/KResult.h>
#include <Kernel/Forward.h>
#include <Kernel/UnixTypes.h>
#include <Kernel/UserOrKernelBuffer.h>
#include <Kernel/VirtualAddress.h>
namespace Kernel {
class File;
class FileBlockerSet final : public Thread::BlockerSet {
public:
FileBlockerSet() { }
virtual bool should_add_blocker(Thread::Blocker& b, void* data) override
{
VERIFY(b.blocker_type() == Thread::Blocker::Type::File);
auto& blocker = static_cast<Thread::FileBlocker&>(b);
return !blocker.unblock_if_conditions_are_met(true, data);
}
void unblock_all_blockers_whose_conditions_are_met()
{
SpinlockLocker lock(m_lock);
BlockerSet::unblock_all_blockers_whose_conditions_are_met_locked([&](auto& b, void* data, bool&) {
VERIFY(b.blocker_type() == Thread::Blocker::Type::File);
auto& blocker = static_cast<Thread::FileBlocker&>(b);
return blocker.unblock_if_conditions_are_met(false, data);
});
}
};
// File is the base class for anything that can be referenced by a OpenFileDescription.
//
// The most important functions in File are:
//
// read() and write()
// - Implement reading and writing.
// - Return the number of bytes read/written, OR a negative error code.
//
// can_read() and can_write()
//
// - Used to implement blocking I/O, and the select() and poll() syscalls.
// - Return true if read() or write() would succeed, respectively.
// - Note that can_read() should return true in EOF conditions,
// and a subsequent call to read() should return 0.
//
// ioctl()
//
// - Optional. If unimplemented, ioctl() on this File will fail with -ENOTTY.
// - Can be overridden in subclasses to implement arbitrary functionality.
// - Subclasses should take care to validate incoming addresses before dereferencing.
//
// mmap()
//
// - Optional. If unimplemented, mmap() on this File will fail with -ENODEV.
// - Called by mmap() when userspace wants to memory-map this File somewhere.
// - Should create a Region in the Process and return it if successful.
class File
: public RefCountedBase
, public Weakable<File> {
public:
virtual bool unref() const;
virtual void before_removing() { }
virtual ~File();
virtual KResultOr<NonnullRefPtr<OpenFileDescription>> open(int options);
virtual KResult close();
virtual bool can_read(const OpenFileDescription&, size_t) const = 0;
virtual bool can_write(const OpenFileDescription&, size_t) const = 0;
virtual KResult attach(OpenFileDescription&);
virtual void detach(OpenFileDescription&);
virtual void did_seek(OpenFileDescription&, off_t) { }
virtual KResultOr<size_t> read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t) = 0;
virtual KResultOr<size_t> write(OpenFileDescription&, u64, const UserOrKernelBuffer&, size_t) = 0;
virtual KResult ioctl(OpenFileDescription&, unsigned request, Userspace<void*> arg);
virtual KResultOr<Memory::Region*> mmap(Process&, OpenFileDescription&, Memory::VirtualRange const&, u64 offset, int prot, bool shared);
virtual KResult stat(::stat&) const { return EBADF; }
// Although this might be better described "name" or "description", these terms already have other meanings.
virtual KResultOr<NonnullOwnPtr<KString>> pseudo_path(const OpenFileDescription&) const = 0;
virtual KResult truncate(u64) { return EINVAL; }
virtual KResult sync() { return EINVAL; }
virtual KResult chown(OpenFileDescription&, UserID, GroupID) { return EBADF; }
virtual KResult chmod(OpenFileDescription&, mode_t) { return EBADF; }
virtual StringView class_name() const = 0;
virtual bool is_seekable() const { return false; }
virtual bool is_inode() const { return false; }
virtual bool is_fifo() const { return false; }
virtual bool is_device() const { return false; }
virtual bool is_tty() const { return false; }
virtual bool is_master_pty() const { return false; }
virtual bool is_block_device() const { return false; }
virtual bool is_character_device() const { return false; }
virtual bool is_socket() const { return false; }
virtual bool is_inode_watcher() const { return false; }
virtual FileBlockerSet& blocker_set() { return m_blocker_set; }
size_t attach_count() const { return m_attach_count; }
protected:
File();
void evaluate_block_conditions()
{
if (Processor::current_in_irq()) {
// If called from an IRQ handler we need to delay evaluation
// and unblocking of waiting threads. Note that this File
// instance may be deleted until the deferred call is executed!
Processor::deferred_call_queue([self = make_weak_ptr()]() {
if (auto file = self.strong_ref())
file->do_evaluate_block_conditions();
});
} else {
do_evaluate_block_conditions();
}
}
private:
ALWAYS_INLINE void do_evaluate_block_conditions()
{
VERIFY(!Processor::current_in_irq());
blocker_set().unblock_all_blockers_whose_conditions_are_met();
}
FileBlockerSet m_blocker_set;
size_t m_attach_count { 0 };
};
}
|
