Kernel/LibC: add dup() syscall and function

libc/include/sys/syscall.h

@@ -40,13 +40,14 @@ __BEGIN_DECLS
 #define SYS_SET_PWD 33
 #define SYS_CLOCK_GETTIME 34
 #define SYS_PIPE 35
-#define SYS_DUP2 36
-#define SYS_RAISE 37
-#define SYS_KILL 38
-#define SYS_SIGNAL 39
-#define SYS_SIGNAL_DONE 40
-#define SYS_TCSETPGRP 41
-#define SYS_GET_PID 42
+#define SYS_DUP 36
+#define SYS_DUP2 37
+#define SYS_RAISE 38
+#define SYS_KILL 39
+#define SYS_SIGNAL 40
+#define SYS_SIGNAL_DONE 41
+#define SYS_TCSETPGRP 42
+#define SYS_GET_PID 43
 
 __END_DECLS
 

libc/unistd.cpp

@@ -61,6 +61,11 @@ ssize_t write(int fildes, const void* buf, size_t nbyte)
 	return syscall(SYS_WRITE, fildes, buf, nbyte);
 }
 
+int dup(int fildes)
+{
+	return syscall(SYS_DUP, fildes);
+}
+
 int dup2(int fildes, int fildes2)
 {
 	return syscall(SYS_DUP2, fildes, fildes2);