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Kernel: Move device lookup to Device class itself

Browse source 
Previously, VFS stored a list of all devices, and devices had to
register and unregister themselves with it. This cleans up things
a bit.
This commit is contained in:
Sergey Bugaev 2019-08-18 14:48:15 +03:00 • committed by Andreas Kling
parent d5352b87b7
commit acccf9ccda
6 changed files with 38 additions and 32 deletions
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29
Kernel/Devices/Device.cpp
View file

@ -1,17 +1,40 @@
#include <Kernel/Devices/Device.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/FileSystem/InodeMetadata.h>
#include <LibC/errno_numbers.h>
static HashMap<u32, Device*>* s_all_devices;
HashMap<u32, Device*>& Device::all_devices()
{
if (s_all_devices == nullptr)
s_all_devices = new HashMap<u32, Device*>;
return *s_all_devices;
}
void Device::for_each(Function<void(Device&)> callback)
{
for (auto& entry : all_devices())
callback(*entry.value);
}
Device* Device::get_device(unsigned major, unsigned minor)
{
auto it = all_devices().find(encoded_device(major, minor));
if (it == all_devices().end())
return nullptr;
return it->value;
}
Device::Device(unsigned major, unsigned minor)
: m_major(major)
, m_minor(minor)
{
VFS::the().register_device({}, *this);
all_devices().set(encoded_device(m_major, m_minor), this);
}
Device::~Device()
{
VFS::the().unregister_device({}, *this);
all_devices().remove(encoded_device(m_major, m_minor));
}
String Device::absolute_path() const

8
Kernel/Devices/Device.h
View file

@ -2,13 +2,14 @@
// Device is the base class of everything that lives in the /dev directory.
//
// All Devices will automatically register with the VFS.
// To expose a Device to the filesystem, simply pass two unique numbers to the constructor,
// and then mknod a file in /dev with those numbers.
//
// There are two main subclasses:
// - BlockDevice (random access)
// - CharacterDevice (sequential)
#include <AK/Function.h>
#include <AK/HashMap.h>
#include <Kernel/FileSystem/File.h>
#include <Kernel/UnixTypes.h>
@ -28,11 +29,16 @@ public:
virtual bool is_device() const override { return true; }
virtual bool is_disk_device() const { return false; }
static void for_each(Function<void(Device&)>);
static Device* get_device(unsigned major, unsigned minor);
protected:
Device(unsigned major, unsigned minor);
void set_uid(uid_t uid) { m_uid = uid; }
void set_gid(gid_t gid) { m_gid = gid; }
static HashMap<u32, Device*>& all_devices();
private:
unsigned m_major { 0 };
unsigned m_minor { 0 };