Kernel: Add procfs that contains only pids

kernel/kernel/FS/ProcFS/FileSystem.cpp

@@ -0,0 +1,46 @@
+#include <kernel/FS/ProcFS/FileSystem.h>
+#include <kernel/FS/ProcFS/Inode.h>
+#include <kernel/FS/RamFS/Inode.h>
+#include <kernel/LockGuard.h>
+
+namespace Kernel
+{
+
+	static ProcFileSystem* s_instance = nullptr;
+
+	void ProcFileSystem::initialize()
+	{
+		ASSERT(s_instance == nullptr);
+		s_instance = new ProcFileSystem(1024 * 1024);
+		ASSERT(s_instance);
+
+		s_instance->m_root_inode = MUST(RamDirectoryInode::create(*s_instance, 0, 0555, 0, 0));
+		MUST(s_instance->set_root_inode(s_instance->m_root_inode));
+	}
+
+	ProcFileSystem& ProcFileSystem::get()
+	{
+		ASSERT(s_instance);
+		return *s_instance;
+	}
+
+	ProcFileSystem::ProcFileSystem(size_t size)
+		: RamFileSystem(size)
+	{
+	}
+
+	BAN::ErrorOr<void> ProcFileSystem::on_process_create(Process& process)
+	{
+		auto path = BAN::String::formatted("{}", process.pid());
+		auto inode = TRY(ProcPidInode::create(process, *this, 0555, 0, 0));
+		TRY(m_root_inode->add_inode(path, inode));
+		return {};
+	}
+
+	void ProcFileSystem::on_process_delete(Process& process)
+	{
+		auto path = BAN::String::formatted("{}", process.pid());
+		MUST(m_root_inode->delete_inode(path));
+	}
+
+}

kernel/kernel/FS/ProcFS/Inode.cpp

@@ -0,0 +1,26 @@
+#include <kernel/FS/ProcFS/Inode.h>
+
+namespace Kernel
+{
+
+	BAN::ErrorOr<BAN::RefPtr<ProcPidInode>> ProcPidInode::create(Process& process, RamFileSystem& fs, mode_t mode, uid_t uid, gid_t gid)
+	{
+		FullInodeInfo inode_info(fs, mode, uid, gid);
+
+		auto* inode_ptr = new ProcPidInode(process, fs, inode_info);
+		if (inode_ptr == nullptr)
+			return BAN::Error::from_errno(ENOMEM);
+		auto inode = BAN::RefPtr<ProcPidInode>::adopt(inode_ptr);
+
+		TRY(inode->add_inode("meminfo"sv, MUST(ProcMemInode::create(process, fs, 0755, 0, 0))));
+
+		return inode;
+	}
+
+	ProcPidInode::ProcPidInode(Process& process, RamFileSystem& fs, const FullInodeInfo& inode_info)
+		: RamDirectoryInode(fs, inode_info, fs.root_inode()->ino())
+		, m_process(process)
+	{
+	}
+
+}