diff --git a/Kernel/include/interface/fcntl.h b/Kernel/include/interface/fcntl.h
new file mode 100644
index 00000000..587c4fda
--- /dev/null
+++ b/Kernel/include/interface/fcntl.h
@@ -0,0 +1,109 @@
+/*
+	This file is part of Fennix Kernel.
+
+	Fennix Kernel is free software: you can redistribute it and/or
+	modify it under the terms of the GNU General Public License as
+	published by the Free Software Foundation, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix Kernel is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#ifndef __FENNIX_API_FCNTL_H__
+#define __FENNIX_API_FCNTL_H__
+
+#ifdef __kernel__
+#include <types.h>
+#endif
+
+/* cmd */
+#define F_DUPFD 0x1
+#define F_DUPFD_CLOEXEC 0x101
+#define F_DUPFD_CLOFORK 0x201
+#define F_GETFD 0x2
+#define F_SETFD 0x3
+#define F_GETFL 0x4
+#define F_SETFL 0x5
+#define F_GETLK 0x6
+#define F_SETLK 0x7
+#define F_SETLKW 0x8
+#define F_OFD_GETLK 0x9
+#define F_OFD_SETLK 0xA
+#define F_OFD_SETLKW 0xB
+#define F_GETOWN 0xC
+#define F_GETOWN_EX 0xD
+#define F_SETOWN 0xE
+#define F_SETOWN_EX 0xF
+
+#define FD_CLOEXEC 0x1
+#define FD_CLOFORK 0x2
+
+/* l_type */
+#define F_RDLCK 0x1
+#define F_UNLCK 0x2
+#define F_WRLCK 0x3
+
+/* type */
+#define F_OWNER_PID 0
+#define F_OWNER_PGRP 1
+
+/* oflag */
+#define O_CLOEXEC 02000000
+#define O_CLOFORK 04000000
+#define O_CREAT 0x8
+#define O_DIRECTORY 0200000
+#define O_EXCL 0x20
+#define O_NOCTTY 0x40
+#define O_NOFOLLOW 0400000
+#define O_TRUNC 0x400
+#define O_TTY_INIT 0x800
+
+#define O_APPEND 0x4
+#define O_DSYNC 0x10
+#define O_NONBLOCK 0x80
+#define O_RSYNC 0x100
+#define O_SYNC 0x200
+
+#define O_ACCMODE 0x3
+
+#define O_EXEC 0x4
+#define O_RDONLY 0x1
+#define O_RDWR 0x3
+#define O_SEARCH 0x10
+#define O_WRONLY 0x2
+
+#define AT_FDCWD
+#define AT_EACCESS
+#define AT_SYMLINK_NOFOLLOW
+#define AT_SYMLINK_FOLLOW
+#define AT_REMOVEDIR
+
+#define POSIX_FADV_DONTNEED
+#define POSIX_FADV_NOREUSE
+#define POSIX_FADV_NORMAL
+#define POSIX_FADV_RANDOM
+#define POSIX_FADV_SEQUENTIAL
+#define POSIX_FADV_WILLNEED
+
+typedef struct f_owner_ex
+{
+	int type;  /* Discriminator for pid. */
+	pid_t pid; /* Process ID or process group ID. */
+} f_owner_ex;
+
+typedef struct flock
+{
+	short l_type;	/* Type of lock; F_RDLCK, F_WRLCK, F_UNLCK. */
+	short l_whence; /* Flag for starting offset. */
+	off_t l_start;	/* Relative offset in bytes. */
+	off_t l_len;	/* Size; if 0 then until EOF. */
+	pid_t l_pid;	/* For a process-owned file lock, ignored on input or the process ID of the owning process on output; for an OFD-owned file lock, zero on input or (pid_t)-1 on output. */
+} flock;
+
+#endif // !__FENNIX_API_FCNTL_H__
diff --git a/Kernel/include/interface/syscalls.h b/Kernel/include/interface/syscalls.h
index df4dcd43..3c0fbcc4 100644
--- a/Kernel/include/interface/syscalls.h
+++ b/Kernel/include/interface/syscalls.h
@@ -18,6 +18,16 @@
 #ifndef __FENNIX_API_SYSTEM_CALLS_LIST_H__
 #define __FENNIX_API_SYSTEM_CALLS_LIST_H__
 
+#if __has_include(<interface/fcntl.h>)
+#include <interface/fcntl.h>
+#else
+#include <fcntl.h>
+#endif
+
+#ifndef __fennix__
+#error "__fennix__ not defined"
+#endif
+
 #pragma region Syscall Wrappers
 
 #define scarg __UINTPTR_TYPE__
@@ -393,18 +403,18 @@ typedef enum
 
 typedef enum
 {
-	__SYS_O_RDONLY = 0x1,
-	__SYS_O_WRONLY = 0x2,
-	__SYS_O_RDWR = 0x3,
-	__SYS_O_APPEND = 0x4,
-	__SYS_O_CREAT = 0x8,
-	__SYS_O_DSYNC = 0x10,
-	__SYS_O_EXCL = 0x20,
-	__SYS_O_NOCTTY = 0x40,
-	__SYS_O_NONBLOCK = 0x80,
-	__SYS_O_RSYNC = 0x100,
-	__SYS_O_SYNC = 0x200,
-	__SYS_O_TRUNC = 0x400
+	__SYS_O_RDONLY = O_RDONLY,
+	__SYS_O_WRONLY = O_WRONLY,
+	__SYS_O_RDWR = O_RDWR,
+	__SYS_O_APPEND = O_APPEND,
+	__SYS_O_CREAT = O_CREAT,
+	__SYS_O_DSYNC = O_DSYNC,
+	__SYS_O_EXCL = O_EXCL,
+	__SYS_O_NOCTTY = O_NOCTTY,
+	__SYS_O_NONBLOCK = O_NONBLOCK,
+	__SYS_O_RSYNC = O_RSYNC,
+	__SYS_O_SYNC = O_SYNC,
+	__SYS_O_TRUNC = O_TRUNC
 } syscall_open_flags_t;
 
 typedef enum
diff --git a/Userspace/Makefile b/Userspace/Makefile
index 68d0b17c..9fd1e563 100644
--- a/Userspace/Makefile
+++ b/Userspace/Makefile
@@ -49,9 +49,14 @@ build_coreutils:
 	make -j$(shell nproc) && \
 	make install
 
+define copy_generic_header
+	cp -f $(WORKSPACE_DIR)/../Kernel/include/interface/$(1) $(WORKSPACE_DIR)/libc/abis/fennix/generic/bits/$(1)
+endef
+
 build_libc:
-	cp -f $(WORKSPACE_DIR)/../Kernel/include/interface/errno.h $(WORKSPACE_DIR)/libc/abis/fennix/generic/bits/errno.h
-	cp -f $(WORKSPACE_DIR)/../Kernel/include/interface/syscalls.h $(WORKSPACE_DIR)/libc/abis/fennix/generic/bits/syscalls.h
+	$(call copy_generic_header,errno.h)
+	$(call copy_generic_header,syscalls.h)
+	$(call copy_generic_header,fcntl.h)
 	mkdir -p cache/libc
 	cd cache/libc && \
 	cmake $(WORKSPACE_DIR)/libc \
diff --git a/Userspace/libc/abis/fennix/generic/bits/fcntl.h b/Userspace/libc/abis/fennix/generic/bits/fcntl.h
new file mode 100644
index 00000000..587c4fda
--- /dev/null
+++ b/Userspace/libc/abis/fennix/generic/bits/fcntl.h
@@ -0,0 +1,109 @@
+/*
+	This file is part of Fennix Kernel.
+
+	Fennix Kernel is free software: you can redistribute it and/or
+	modify it under the terms of the GNU General Public License as
+	published by the Free Software Foundation, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix Kernel is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#ifndef __FENNIX_API_FCNTL_H__
+#define __FENNIX_API_FCNTL_H__
+
+#ifdef __kernel__
+#include <types.h>
+#endif
+
+/* cmd */
+#define F_DUPFD 0x1
+#define F_DUPFD_CLOEXEC 0x101
+#define F_DUPFD_CLOFORK 0x201
+#define F_GETFD 0x2
+#define F_SETFD 0x3
+#define F_GETFL 0x4
+#define F_SETFL 0x5
+#define F_GETLK 0x6
+#define F_SETLK 0x7
+#define F_SETLKW 0x8
+#define F_OFD_GETLK 0x9
+#define F_OFD_SETLK 0xA
+#define F_OFD_SETLKW 0xB
+#define F_GETOWN 0xC
+#define F_GETOWN_EX 0xD
+#define F_SETOWN 0xE
+#define F_SETOWN_EX 0xF
+
+#define FD_CLOEXEC 0x1
+#define FD_CLOFORK 0x2
+
+/* l_type */
+#define F_RDLCK 0x1
+#define F_UNLCK 0x2
+#define F_WRLCK 0x3
+
+/* type */
+#define F_OWNER_PID 0
+#define F_OWNER_PGRP 1
+
+/* oflag */
+#define O_CLOEXEC 02000000
+#define O_CLOFORK 04000000
+#define O_CREAT 0x8
+#define O_DIRECTORY 0200000
+#define O_EXCL 0x20
+#define O_NOCTTY 0x40
+#define O_NOFOLLOW 0400000
+#define O_TRUNC 0x400
+#define O_TTY_INIT 0x800
+
+#define O_APPEND 0x4
+#define O_DSYNC 0x10
+#define O_NONBLOCK 0x80
+#define O_RSYNC 0x100
+#define O_SYNC 0x200
+
+#define O_ACCMODE 0x3
+
+#define O_EXEC 0x4
+#define O_RDONLY 0x1
+#define O_RDWR 0x3
+#define O_SEARCH 0x10
+#define O_WRONLY 0x2
+
+#define AT_FDCWD
+#define AT_EACCESS
+#define AT_SYMLINK_NOFOLLOW
+#define AT_SYMLINK_FOLLOW
+#define AT_REMOVEDIR
+
+#define POSIX_FADV_DONTNEED
+#define POSIX_FADV_NOREUSE
+#define POSIX_FADV_NORMAL
+#define POSIX_FADV_RANDOM
+#define POSIX_FADV_SEQUENTIAL
+#define POSIX_FADV_WILLNEED
+
+typedef struct f_owner_ex
+{
+	int type;  /* Discriminator for pid. */
+	pid_t pid; /* Process ID or process group ID. */
+} f_owner_ex;
+
+typedef struct flock
+{
+	short l_type;	/* Type of lock; F_RDLCK, F_WRLCK, F_UNLCK. */
+	short l_whence; /* Flag for starting offset. */
+	off_t l_start;	/* Relative offset in bytes. */
+	off_t l_len;	/* Size; if 0 then until EOF. */
+	pid_t l_pid;	/* For a process-owned file lock, ignored on input or the process ID of the owning process on output; for an OFD-owned file lock, zero on input or (pid_t)-1 on output. */
+} flock;
+
+#endif // !__FENNIX_API_FCNTL_H__
diff --git a/Userspace/libc/abis/fennix/generic/bits/syscalls.h b/Userspace/libc/abis/fennix/generic/bits/syscalls.h
index df4dcd43..3c0fbcc4 100644
--- a/Userspace/libc/abis/fennix/generic/bits/syscalls.h
+++ b/Userspace/libc/abis/fennix/generic/bits/syscalls.h
@@ -18,6 +18,16 @@
 #ifndef __FENNIX_API_SYSTEM_CALLS_LIST_H__
 #define __FENNIX_API_SYSTEM_CALLS_LIST_H__
 
+#if __has_include(<interface/fcntl.h>)
+#include <interface/fcntl.h>
+#else
+#include <fcntl.h>
+#endif
+
+#ifndef __fennix__
+#error "__fennix__ not defined"
+#endif
+
 #pragma region Syscall Wrappers
 
 #define scarg __UINTPTR_TYPE__
@@ -393,18 +403,18 @@ typedef enum
 
 typedef enum
 {
-	__SYS_O_RDONLY = 0x1,
-	__SYS_O_WRONLY = 0x2,
-	__SYS_O_RDWR = 0x3,
-	__SYS_O_APPEND = 0x4,
-	__SYS_O_CREAT = 0x8,
-	__SYS_O_DSYNC = 0x10,
-	__SYS_O_EXCL = 0x20,
-	__SYS_O_NOCTTY = 0x40,
-	__SYS_O_NONBLOCK = 0x80,
-	__SYS_O_RSYNC = 0x100,
-	__SYS_O_SYNC = 0x200,
-	__SYS_O_TRUNC = 0x400
+	__SYS_O_RDONLY = O_RDONLY,
+	__SYS_O_WRONLY = O_WRONLY,
+	__SYS_O_RDWR = O_RDWR,
+	__SYS_O_APPEND = O_APPEND,
+	__SYS_O_CREAT = O_CREAT,
+	__SYS_O_DSYNC = O_DSYNC,
+	__SYS_O_EXCL = O_EXCL,
+	__SYS_O_NOCTTY = O_NOCTTY,
+	__SYS_O_NONBLOCK = O_NONBLOCK,
+	__SYS_O_RSYNC = O_RSYNC,
+	__SYS_O_SYNC = O_SYNC,
+	__SYS_O_TRUNC = O_TRUNC
 } syscall_open_flags_t;
 
 typedef enum
diff --git a/Userspace/libc/include/fcntl.h b/Userspace/libc/include/fcntl.h
index e76907d1..f77ad800 100644
--- a/Userspace/libc/include/fcntl.h
+++ b/Userspace/libc/include/fcntl.h
@@ -24,77 +24,7 @@ extern "C"
 #endif // __cplusplus
 
 #include <sys/types.h>
-
-	typedef struct f_owner_ex
-	{
-		int type;  /* Discriminator for pid. */
-		pid_t pid; /* Process ID or process group ID. */
-	} f_owner_ex;
-
-	typedef struct flock
-	{
-		short l_type;	/* Type of lock; F_RDLCK, F_WRLCK, F_UNLCK. */
-		short l_whence; /* Flag for starting offset. */
-		off_t l_start;	/* Relative offset in bytes. */
-		off_t l_len;	/* Size; if 0 then until EOF. */
-		pid_t l_pid;	/* For a process-owned file lock, ignored on input or the process ID of the owning process on output; for an OFD-owned file lock, zero on input or (pid_t)-1 on output. */
-	} flock;
-
-#define F_DUPFD
-#define F_DUPFD_CLOEXEC
-#define F_DUPFD_CLOFORK
-#define F_GETFD
-#define F_SETFD
-#define F_GETFL
-#define F_SETFL
-#define F_GETLK
-#define F_SETLK
-#define F_SETLKW
-#define F_OFD_GETLK
-#define F_OFD_SETLK
-#define F_OFD_SETLKW
-#define F_GETOWN
-#define F_GETOWN_EX
-#define F_SETOWN
-#define F_SETOWN_EX
-#define FD_CLOEXEC
-#define FD_CLOFORK
-#define F_RDLCK
-#define F_UNLCK
-#define F_WRLCK
-#define F_OWNER_PID
-#define F_OWNER_PGRP
-#define O_CLOEXEC 02000000
-#define O_CLOFORK
-#define O_CREAT 0100
-#define O_DIRECTORY
-#define O_EXCL 0200
-#define O_NOCTTY
-#define O_NOFOLLOW 0400000
-#define O_TRUNC 01000
-#define O_TTY_INIT
-#define O_APPEND 02000
-#define O_DSYNC
-#define O_NONBLOCK
-#define O_RSYNC
-#define O_SYNC
-#define O_ACCMODE
-#define O_EXEC
-#define O_RDONLY 00
-#define O_RDWR 02
-#define O_SEARCH
-#define O_WRONLY 01
-#define AT_FDCWD
-#define AT_EACCESS
-#define AT_SYMLINK_NOFOLLOW
-#define AT_SYMLINK_FOLLOW
-#define AT_REMOVEDIR
-#define POSIX_FADV_DONTNEED
-#define POSIX_FADV_NOREUSE
-#define POSIX_FADV_NORMAL
-#define POSIX_FADV_RANDOM
-#define POSIX_FADV_SEQUENTIAL
-#define POSIX_FADV_WILLNEED
+#include <bits/fcntl.h>
 
 	int creat(const char *path, mode_t mode);
 	int fcntl(int fildes, int cmd, ...);