diff --git a/Kernel.config b/Kernel.config
new file mode 100644
index 0000000..cfd0c60
--- /dev/null
+++ b/Kernel.config
@@ -0,0 +1,2 @@
+ENABLE_UNIX=0
+ENABLE_NET=0
diff --git a/etc/Kernel.makefile b/etc/Kernel.makefile
index a6bfe51..8f2c048 100644
--- a/etc/Kernel.makefile
+++ b/etc/Kernel.makefile
@@ -7,6 +7,7 @@ ACPICA_OBJ=$(ACPICA_SRC:%.c=$(O)/%.o)
 
 KERNEL_USER_HDR=$(shell find include/user -type f -name "*.h")
 
+KERNEL_DEF=
 KERNEL_OBJ=$(O)/arch/amd64/entry.o \
 		   $(O)/arch/amd64/kernel.o \
 		   $(O)/arch/amd64/acpi_osl_mem.o \
@@ -107,12 +108,6 @@ KERNEL_OBJ=$(O)/arch/amd64/entry.o \
 		   $(O)/drivers/usb/device.o \
 		   $(O)/drivers/usb/usbkbd.o \
 		   $(O)/drivers/usb/hub.o \
-		   $(O)/arch/amd64/hw/vesa.o \
-		   $(O)/net/if.o \
-		   $(O)/net/net.o \
-		   $(O)/net/socket.o \
-		   $(O)/net/unix.o \
-		   $(O)/sys/sys_net.o
 
 KERNEL_LDS=arch/amd64/link.ld
 KERNEL_HDR=$(shell find include -type f -name "*.h")
@@ -133,8 +128,11 @@ DIRS+=$(O)/arch/amd64/hw \
 	  $(O)/include \
 	  $(ACPICA_DIR)
 
+include etc/KernelOptions.makefile
+
 ### Compiler
 
+KERNEL_GIT_VERSION=$(shell git describe --always --tags)
 KERNEL_CFLAGS=-Iinclude \
 			  -Iinclude/arch/amd64/acpica \
 			  -I$(O)/include \
@@ -143,7 +141,7 @@ KERNEL_CFLAGS=-Iinclude \
 			  -fno-plt \
 			  -fno-pic \
 			  -DARCH_AMD64 \
-			  -DKERNEL_VERSION_STR=\"testing\" \
+			  -DKERNEL_VERSION_STR=\"$(KERNEL_GIT_VERSION)\" \
 			  -D__KERNEL__ \
 			  -mcmodel=large \
 			  -mno-sse \
@@ -156,13 +154,7 @@ KERNEL_CFLAGS=-Iinclude \
 			  -Wno-unused \
 			  -O0 \
 			  -ggdb \
-			  -Werror \
-			  -DENABLE_UNIX=1 \
-			  -DENABLE_NET=1 \
-			  -DVESA_ENABLE=1 \
-			  -DVESA_WIDTH=640 \
-			  -DVESA_HEIGHT=480 \
-			  -DVESA_DEPTH=32
+			  -Werror $(KERNEL_DEF)
 KERNEL_LDFLAGS=-nostdlib \
 			   -fPIE \
 			   -fno-plt \
@@ -182,11 +174,11 @@ $(O)/include/config.h: config.h.in
 	@echo " CONFIG $@"
 	@cp $< $@
 
-$(O)/%.o: %.c $(O)/include/config.h $(KERNEL_HDR)
+$(O)/%.o: %.c $(O)/include/config.h $(KERNEL_HDR) Kernel.config
 	@echo " CC  $@"
 	@$(CC) $(KERNEL_CFLAGS) -c -o $@ $<
 
-$(O)/%.o: %.S $(O)/include/config.h $(KERNEL_HDR)
+$(O)/%.o: %.S $(O)/include/config.h $(KERNEL_HDR) Kernel.config
 	@echo " AS  $@"
 	@$(CC) $(KERNEL_CFLAGS) -D__ASM__ -c -o $@ $<
 
diff --git a/etc/KernelOptions.makefile b/etc/KernelOptions.makefile
new file mode 100644
index 0000000..17b364b
--- /dev/null
+++ b/etc/KernelOptions.makefile
@@ -0,0 +1,22 @@
+include Kernel.config
+
+ifeq ($(ENABLE_UNIX),1)
+KERNEL_DEF+=-DENABLE_UNIX=1
+KERNEL_OBJ+=$(O)/net/unix.o
+endif
+
+ifeq ($(ENABLE_NET),1)
+KERNEL_DEF+=-DENABLE_NET=1
+KERNEL_OBJ+=$(O)/net/if.o \
+		    $(O)/net/net.o \
+		    $(O)/net/socket.o \
+		    $(O)/sys/sys_net.o
+endif
+
+ifeq ($(ENABLE_VESA),1)
+KERNEL_DEF+=-DVESA_ENABLE=1 \
+			-DVESA_WIDTH=$(VESA_WIDTH) \
+			-DVESA_HEIGHT=$(VESA_HEIGHT) \
+			-DVESA_DEPTH=$(VESA_DEPTH)
+KERNEL_OBJ+=$(O)/arch/amd64/hw/vesa.o
+endif
diff --git a/fs/vfs_ops.c b/fs/vfs_ops.c
index f857be3..168389c 100644
--- a/fs/vfs_ops.c
+++ b/fs/vfs_ops.c
@@ -59,7 +59,7 @@ static const char *vfs_path_parent(const char *input, char *dst) {
 static int vfs_opendir(struct vfs_ioctx *ctx, struct ofile *fd) {
     _assert(ctx);
     _assert(fd);
-    _assert(!(fd->flags & OF_SOCKET));
+    _assert(!ofile_is_socket(fd));
 
     struct vnode *node = fd->file.vnode;
 
@@ -97,7 +97,7 @@ static int vfs_opendir(struct vfs_ioctx *ctx, struct ofile *fd) {
 int vfs_readdir(struct vfs_ioctx *ctx, struct ofile *fd, struct dirent *ent) {
     _assert(ctx);
     _assert(fd);
-    _assert(!(fd->flags & OF_SOCKET));
+    _assert(!ofile_is_socket(fd));
 
     if (!(fd->flags & OF_DIRECTORY)) {
         return -ENOTDIR;
@@ -183,7 +183,10 @@ int vfs_open_vnode(struct vfs_ioctx *ctx, struct ofile *fd, struct vnode *node,
     _assert(ctx);
     _assert(fd);
     _assert(node);
+#if defined(ENABLE_NET)
+    // ??
     fd->flags &= ~OF_SOCKET;
+#endif
 
     if (node->type == VN_SOCK) {
         return -ENODEV;
@@ -480,7 +483,7 @@ int vfs_openat(struct vfs_ioctx *ctx,
 void vfs_close(struct vfs_ioctx *ctx, struct ofile *fd) {
     _assert(ctx);
     _assert(fd);
-    _assert(!(fd->flags & OF_SOCKET));
+    _assert(!ofile_is_socket(fd));
     _assert(!(fd->refcount));
     _assert(fd->file.vnode);
 
@@ -563,7 +566,7 @@ ssize_t vfs_write(struct vfs_ioctx *ctx, struct ofile *fd, const void *buf, size
     ssize_t b;
 
     _assert(fd);
-    _assert(!(fd->flags & OF_SOCKET));
+    _assert(!ofile_is_socket(fd));
 
     if (!(fd->flags & OF_WRITABLE) || (fd->flags & OF_DIRECTORY)) {
         return -EINVAL;
@@ -601,7 +604,7 @@ ssize_t vfs_read(struct vfs_ioctx *ctx, struct ofile *fd, void *buf, size_t coun
     }
 
     _assert(fd);
-    _assert(!(fd->flags & OF_SOCKET));
+    _assert(!ofile_is_socket(fd));
 
     node = fd->file.vnode;
 
@@ -635,12 +638,12 @@ ssize_t vfs_read(struct vfs_ioctx *ctx, struct ofile *fd, void *buf, size_t coun
 
 off_t vfs_lseek(struct vfs_ioctx *ctx, struct ofile *fd, off_t offset, int whence) {
     _assert(fd);
-    _assert(!(fd->flags & OF_SOCKET));
+    _assert(!ofile_is_socket(fd));
     struct vnode *node = fd->file.vnode;
     _assert(node);
 
     if (node->type != VN_REG) {
-        return -EINVAL;
+        return -ESPIPE;
     }
 
     if (!node->op || !node->op->lseek) {
@@ -723,7 +726,7 @@ int vfs_chown(struct vfs_ioctx *ctx, const char *path, uid_t uid, gid_t gid) {
 int vfs_ioctl(struct vfs_ioctx *ctx, struct ofile *fd, unsigned int cmd, void *arg) {
     _assert(ctx);
     _assert(fd);
-    _assert(!(fd->flags & OF_SOCKET));
+    _assert(!ofile_is_socket(fd));
     struct vnode *node = fd->file.vnode;
     _assert(node);
 
diff --git a/include/fs/ofile.h b/include/fs/ofile.h
index 44833c4..094b548 100644
--- a/include/fs/ofile.h
+++ b/include/fs/ofile.h
@@ -9,7 +9,6 @@
 #define OF_MEMDIR           (1 << 3)
 #define OF_MEMDIR_DOT       (1 << 4)
 #define OF_MEMDIR_DOTDOT    (1 << 5)
-#define OF_SOCKET           (1 << 6)
 #define OF_CLOEXEC          (1 << 7)
 
 struct vfs_ioctx;
@@ -27,6 +26,16 @@ struct ofile {
     };
 };
 
+#if defined(ENABLE_NET)
+#define OF_SOCKET                   (1 << 6)
+
+static inline int ofile_is_socket(struct ofile *of) {
+    return !!(of->flags & OF_SOCKET);
+}
+#else
+#define ofile_is_socket(of)         0
+#endif
+
 struct ofile *ofile_create(void);
 struct ofile *ofile_dup(struct ofile *of);
 void ofile_destroy(struct ofile *of);
diff --git a/sys/char/pipe.c b/sys/char/pipe.c
index f458f21..b2c170c 100644
--- a/sys/char/pipe.c
+++ b/sys/char/pipe.c
@@ -115,7 +115,6 @@ static void pipe_vnode_close(struct ofile *of) {
 }
 
 static int pipe_vnode_open(struct ofile *of, int opt) {
-    _assert(!(of->flags & OF_SOCKET));
     _assert(of->file.vnode);
     // TODO: allow only one reader and many writers
     of->file.pos = 0;
diff --git a/sys/mem/shmem.c b/sys/mem/shmem.c
index 2d28cd7..6f9ec0e 100644
--- a/sys/mem/shmem.c
+++ b/sys/mem/shmem.c
@@ -116,7 +116,7 @@ void *sys_mmap(void *hint, size_t length, int prot, int flags, int fd, off_t off
             return (void *) -EBADF;
         }
 
-        if (of->flags & OF_SOCKET) {
+        if (ofile_is_socket(of)) {
             return (void *) -EINVAL;
         }
 
diff --git a/sys/sys_file.c b/sys/sys_file.c
index e3c0850..b7ea98a 100644
--- a/sys/sys_file.c
+++ b/sys/sys_file.c
@@ -51,7 +51,7 @@ ssize_t sys_read(int fd, void *data, size_t lim) {
         return -EBADF;
     }
 
-    if (of->flags & OF_SOCKET) {
+    if (ofile_is_socket(of)) {
         kwarn("Invalid operation on socket\n");
         return -EINVAL;
     }
@@ -67,7 +67,7 @@ ssize_t sys_write(int fd, const void *data, size_t lim) {
         return -EBADF;
     }
 
-    if (of->flags & OF_SOCKET) {
+    if (ofile_is_socket(of)) {
         kwarn("Invalid operation on socket\n");
         return -EINVAL;
     }
@@ -123,7 +123,7 @@ int sys_ftruncate(int fd, off_t length) {
     if (!of) {
         return -EBADF;
     }
-    if (of->flags & OF_SOCKET) {
+    if (ofile_is_socket(of)) {
         kwarn("truncate() on socket\n");
         return -EINVAL;
     }
@@ -197,7 +197,7 @@ int sys_openat(int dfd, const char *filename, int flags, int mode) {
 
     // Set controlling terminal if none present and TTY is opened
     // TODO: O_NOCTTY
-    if (!proc->ctty && !(ofile->flags & OF_SOCKET)) {
+    if (!proc->ctty && !ofile_is_socket(ofile)) {
         struct vnode *node = ofile->file.vnode;
         _assert(node);
 
@@ -352,7 +352,7 @@ off_t sys_lseek(int fd, off_t offset, int whence) {
         return -EBADF;
     }
 
-    if (ofile->flags & OF_SOCKET) {
+    if (ofile_is_socket(ofile)) {
         kwarn("Invalid operation on socket\n");
         return -EINVAL;
     }
@@ -366,7 +366,7 @@ int sys_ioctl(int fd, unsigned int cmd, void *arg) {
         return -EBADF;
     }
 
-    if (of->flags & OF_SOCKET) {
+    if (ofile_is_socket(of)) {
         kwarn("Invalid operation on socket\n");
         return -EINVAL;
     }
@@ -382,7 +382,7 @@ ssize_t sys_readdir(int fd, struct dirent *ent) {
         return -EBADF;
     }
 
-    if (of->flags & OF_SOCKET) {
+    if (ofile_is_socket(of)) {
         kwarn("Invalid operation on socket\n");
         return -EINVAL;
     }
@@ -413,7 +413,7 @@ int sys_mknod(const char *filename, int mode, unsigned int dev) {
 
 static int sys_select_get_ready(struct ofile *fd) {
 #if defined(ENABLE_NET)
-    if (fd->flags & OF_SOCKET) {
+    if (ofile_is_socket(fd)) {
         return socket_has_data(&fd->socket);
     } else
 #endif
@@ -440,11 +440,14 @@ static int sys_select_get_ready(struct ofile *fd) {
 }
 
 static struct io_notify *sys_select_get_wait(struct ofile *fd) {
-    if (fd->flags & OF_SOCKET) {
+#if defined(ENABLE_NET)
+    if (ofile_is_socket(fd)) {
         struct io_notify *res = socket_get_rx_notify(&fd->socket);
         _assert(res);
         return res;
-    } else {
+    } else
+#endif
+    {
         struct vnode *vn = fd->file.vnode;
         _assert(vn);
 
diff --git a/sys/thread.c b/sys/thread.c
index 40cf844..2c76b73 100644
--- a/sys/thread.c
+++ b/sys/thread.c
@@ -996,7 +996,7 @@ pid_t sys_setsid(void) {
     if (proc->ctty) {
         // Close current tty filedes
         for (size_t i = 0; i < THREAD_MAX_FDS; ++i) {
-            if (proc->fds[i] && !(proc->fds[i]->flags & OF_SOCKET)) {
+            if (proc->fds[i] && !ofile_is_socket(proc->fds[i])) {
                 if (proc->fds[i]->file.vnode == proc->ctty) {
                     kdebug("setsid: detaching fd %d from #%d (%s)\n", i, proc->pid, proc->name);
                     ofile_close(&proc->ioctx, proc->fds[i]);