int fork(void); int exit(void) __attribute__((noreturn)); int wait(void); int cons_putc(int); int pipe(int*); int write(int, void*, int); int read(int, void*, int); int close(int); int block(void); int kill(int); int panic(char*); int cons_puts(char*); int exec(char *, char **); int open(char *, int); int mknod (char*,short,short,short); int unlink (char*); int puts(char*); int puts1(char*); char* strcpy(char*, char*); void printf(int fd, char *fmt, ...);