From 04c7e52689effe1efe84a333ccee574c6cf2ad69 Mon Sep 17 00:00:00 2001
From: JJ <fidojj@hotmail.com>
Date: Sun, 31 Oct 2021 12:30:11 +1100
Subject: [PATCH] Kernel: Implement syscalls for epoll

---
 Kernel/include/Fs/EPoll.h                 | 31 +++++++++++++++++++++++
 Kernel/include/Fs/Filesystem.h            | 13 +++++-----
 Kernel/include/OnCleanup.h                | 18 +++++++++++++
 LibLemon/include/Lemon/System/ABI/EPoll.h | 31 +++++++++++++++++++++++
 4 files changed, 87 insertions(+), 6 deletions(-)
 create mode 100644 Kernel/include/Fs/EPoll.h
 create mode 100644 Kernel/include/OnCleanup.h
 create mode 100644 LibLemon/include/Lemon/System/ABI/EPoll.h

diff --git a/Kernel/include/Fs/EPoll.h b/Kernel/include/Fs/EPoll.h
new file mode 100644
index 00000000..fd9f968e
--- /dev/null
+++ b/Kernel/include/Fs/EPoll.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <ABI/EPoll.h>
+#include <Fs/Filesystem.h>
+#include <List.h>
+#include <Pair.h>
+
+namespace fs {
+
+class EPoll :
+    public FsNode {
+public:
+    EPoll() = default;
+
+    void Close() override {
+        handleCount--;
+
+        if(handleCount <= 0){
+            delete this;
+        }
+    }
+
+    bool IsEPoll() const override {
+        return true;
+    }
+
+    List<Pair<int, epoll_event>> fds;
+    lock_t epLock = 0;
+};
+
+}
diff --git a/Kernel/include/Fs/Filesystem.h b/Kernel/include/Fs/Filesystem.h
index 5a302ed7..89087e9c 100755
--- a/Kernel/include/Fs/Filesystem.h
+++ b/Kernel/include/Fs/Filesystem.h
@@ -39,12 +39,12 @@
 
 #define FS_NODE_TYPE 0xF000
 #define FS_NODE_FILE S_IFREG
-#define FS_NODE_DIRECTORY S_IFDIR  // 0x2
-#define FS_NODE_MOUNTPOINT S_IFDIR // 0x8
-#define FS_NODE_BLKDEVICE S_IFBLK  // 0x10
-#define FS_NODE_SYMLINK S_IFLNK    // 0x20
-#define FS_NODE_CHARDEVICE S_IFCHR // 0x40
-#define FS_NODE_SOCKET S_IFSOCK    // 0x80
+#define FS_NODE_DIRECTORY S_IFDIR 
+#define FS_NODE_MOUNTPOINT S_IFDIR
+#define FS_NODE_BLKDEVICE S_IFBLK 
+#define FS_NODE_SYMLINK S_IFLNK   
+#define FS_NODE_CHARDEVICE S_IFCHR
+#define FS_NODE_SOCKET S_IFSOCK   
 
 #define POLLIN 0x01
 #define POLLOUT 0x02
@@ -217,6 +217,7 @@ class FsNode {
     virtual inline bool IsSymlink() { return (flags & FS_NODE_TYPE) == FS_NODE_SYMLINK; }
     virtual inline bool IsCharDevice() { return (flags & FS_NODE_TYPE) == FS_NODE_CHARDEVICE; }
     virtual inline bool IsSocket() { return (flags & FS_NODE_TYPE) == FS_NODE_SOCKET; }
+    virtual inline bool IsEPoll() const { return false; }
 
     void UnblockAll();
 
diff --git a/Kernel/include/OnCleanup.h b/Kernel/include/OnCleanup.h
new file mode 100644
index 00000000..959f6831
--- /dev/null
+++ b/Kernel/include/OnCleanup.h
@@ -0,0 +1,18 @@
+#pragma once
+
+#include <Compiler.h>
+
+template <typename T>
+concept CleanupFunction = requires(T t) {
+    t();
+};
+
+template <CleanupFunction F> class OnCleanup {
+public:
+    ALWAYS_INLINE OnCleanup(F&& func) : m_func(func) {}
+
+    ALWAYS_INLINE ~OnCleanup() { m_func(); }
+
+private:
+    F m_func;
+};
diff --git a/LibLemon/include/Lemon/System/ABI/EPoll.h b/LibLemon/include/Lemon/System/ABI/EPoll.h
new file mode 100644
index 00000000..0f68f3bc
--- /dev/null
+++ b/LibLemon/include/Lemon/System/ABI/EPoll.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <stdint.h>
+
+#define EPOLL_CLOEXEC 1
+#define EPOLL_NONBLOCK 2
+
+#define EPOLLIN 0x001
+#define EPOLLPRI 0x002
+#define EPOLLOUT 0x004
+#define EPOLLRDNORM 0x040
+#define EPOLLRDBAND 0x080
+#define EPOLLWRNORM 0x100
+#define EPOLLWRBAND 0x200
+#define EPOLLMSG 0x400
+#define EPOLLERR 0x008
+#define EPOLLHUP 0x010
+#define EPOLLRDHUP 0x2000
+#define EPOLLEXCLUSIVE (1U << 28)
+#define EPOLLWAKEUP (1U << 29)
+#define EPOLLONESHOT (1U << 30)
+#define EPOLLET (1U << 31)
+
+#define EPOLL_CTL_ADD 1
+#define EPOLL_CTL_DEL 2
+#define EPOLL_CTL_MOD 3
+
+struct epoll_event {
+	uint32_t events;
+	uint64_t data;
+};