syscalls: linkat

kernel-src/include/kernel/syscalls.h

@@ -3,10 +3,41 @@
 
 #include <stdint.h>
 #include <arch/context.h>
+#include <kernel/vfs.h>
+#include <kernel/file.h>
+#include <kernel/scheduler.h>
 
 typedef struct {
 	uint64_t ret;
 	uint64_t errno;
 } syscallret_t;
 
+static inline int dirfd_enter(char *path, int dirfd, file_t **file, vnode_t **dirnode) {
+	if (*path == '/') {
+		*dirnode = sched_getroot();
+	} else if (dirfd == AT_FDCWD) {
+		*dirnode = sched_getcwd();
+	} else {
+		*file = fd_get(dirfd);
+		if (file == NULL) {
+			return EBADF;
+		}
+
+		*dirnode = (*file)->vnode;
+
+		if ((*dirnode)->type != V_TYPE_DIR) {
+			fd_release(*file);
+			return ENOTDIR;
+		}
+	}
+	return 0;
+}
+
+static inline void dirfd_leave(vnode_t *dirnode, file_t *file) {
+	if (file)
+		fd_release(file);
+	else
+		VOP_RELEASE(dirnode);
+}
+
 #endif