diff --git a/apue.h b/apue.h
new file mode 100644
index 0000000000000000000000000000000000000000..3094d4428c30d3bb8f8b529c533655f14076d64f
--- /dev/null
+++ b/apue.h
@@ -0,0 +1,108 @@
+/* Our own header, to be included *after* all standard system headers */
+
+#ifndef	APUE_H
+#define	APUE_H
+
+#include	<sys/types.h>	/* required for some of our prototypes */
+#include	<stdio.h>		/* for convenience */
+#include	<stdlib.h>		/* for convenience */
+#include	<string.h>		/* for convenience */
+#include	<unistd.h>		/* for convenience */
+
+#define	MAXLINE	4096			/* max line length */
+
+#define	FILE_MODE	(S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
+					/* default file access permissions for new files */
+#define	DIR_MODE	(FILE_MODE | S_IXUSR | S_IXGRP | S_IXOTH)
+					/* default permissions for new directories */
+
+typedef	void	Sigfunc(int);	/* for signal handlers */
+
+					/* 4.3BSD Reno <signal.h> doesn't define SIG_ERR */
+#if	defined(SIG_IGN) && !defined(SIG_ERR)
+#define	SIG_ERR	((Sigfunc *)-1)
+#endif
+
+#define	min(a,b)	((a) < (b) ? (a) : (b))
+#define	max(a,b)	((a) > (b) ? (a) : (b))
+
+					/* prototypes for our own functions */
+char	*path_alloc(int *);			/* {Prog pathalloc} */
+int		 open_max(void);			/* {Prog openmax} */
+void	 clr_fl(int, int);			/* {Prog setfl} */
+void	 set_fl(int, int);			/* {Prog setfl} */
+void	 pr_exit(int);				/* {Prog prexit} */
+void	 pr_mask(const char *);		/* {Prog prmask} */
+Sigfunc	*signal_intr(int, Sigfunc *);/* {Prog signal_intr_function} */
+
+int		 tty_cbreak(int);			/* {Prog raw} */
+int		 tty_raw(int);				/* {Prog raw} */
+int		 tty_reset(int);			/* {Prog raw} */
+void	 tty_atexit(void);			/* {Prog raw} */
+#ifdef	ECHO	/* only if <termios.h> has been included */
+struct termios	*tty_termios(void);	/* {Prog raw} */
+#endif
+
+void	 sleep_us(unsigned int);	/* {Ex sleepus} */
+ssize_t	 readn(int, void *, size_t);/* {Prog readn} */
+ssize_t	 writen(int, const void *, size_t);/* {Prog writen} */
+int		 daemon_init(void);			/* {Prog daemoninit} */
+
+int		 s_pipe(int *);				/* {Progs svr4_spipe bsd_spipe} */
+int		 recv_fd(int, ssize_t (*func)(int, const void *, size_t));
+									/* {Progs recvfd_svr4 recvfd_43bsd} */
+int		 send_fd(int, int);			/* {Progs sendfd_svr4 sendfd_43bsd} */
+int		 send_err(int, int, const char *);/* {Prog senderr} */
+int		 serv_listen(const char *);	/* {Progs servlisten_svr4 servlisten_44bsd} */
+int		 serv_accept(int, uid_t *);	/* {Progs servaccept_svr4 servaccept_44bsd} */
+int		 cli_conn(const char *);	/* {Progs cliconn_svr4 cliconn_44bsd} */
+int		 buf_args(char *, int (*func)(int, char **));
+									/* {Prog bufargs} */
+
+int		 ptym_open(char *);			/* {Progs ptyopen_svr4 ptyopen_44bsd} */
+int		 ptys_open(int, char *);	/* {Progs ptyopen_svr4 ptyopen_44bsd} */
+#ifdef	TIOCGWINSZ
+pid_t	 pty_fork(int *, char *, const struct termios *,
+				  const struct winsize *);	/* {Prog ptyfork} */
+#endif
+
+int		lock_reg(int, int, int, off_t, int, off_t);
+									/* {Prog lockreg} */
+#define	read_lock(fd, offset, whence, len) \
+			lock_reg(fd, F_SETLK, F_RDLCK, offset, whence, len)
+#define	readw_lock(fd, offset, whence, len) \
+			lock_reg(fd, F_SETLKW, F_RDLCK, offset, whence, len)
+#define	write_lock(fd, offset, whence, len) \
+			lock_reg(fd, F_SETLK, F_WRLCK, offset, whence, len)
+#define	writew_lock(fd, offset, whence, len) \
+			lock_reg(fd, F_SETLKW, F_WRLCK, offset, whence, len)
+#define	un_lock(fd, offset, whence, len) \
+			lock_reg(fd, F_SETLK, F_UNLCK, offset, whence, len)
+
+pid_t	lock_test(int, int, off_t, int, off_t);
+									/* {Prog locktest} */
+
+#define	is_readlock(fd, offset, whence, len) \
+			lock_test(fd, F_RDLCK, offset, whence, len)
+#define	is_writelock(fd, offset, whence, len) \
+			lock_test(fd, F_WRLCK, offset, whence, len)
+
+void	err_dump(const char *, ...);	/* {App misc_source} */
+void	err_msg(const char *, ...);
+void	err_quit(const char *, ...);
+void	err_ret(const char *, ...);
+void	err_sys(const char *, ...);
+
+void	log_msg(const char *, ...);		/* {App misc_source} */
+void	log_open(const char *, int, int);
+void	log_quit(const char *, ...);
+void	log_ret(const char *, ...);
+void	log_sys(const char *, ...);
+
+void	TELL_WAIT(void);		/* parent/child from {Sec race_conditions} */
+void	TELL_PARENT(pid_t);
+void	TELL_CHILD(pid_t);
+void	WAIT_PARENT(void);
+void	WAIT_CHILD(void);
+
+#endif	/* __ourhdr_h */
diff --git a/error.c b/error.c
new file mode 100644
index 0000000000000000000000000000000000000000..775cdb25b7ecf2dc626c0e6f1843ba4c21f8eeee
--- /dev/null
+++ b/error.c
@@ -0,0 +1,98 @@
+#include	<errno.h>		/* for definition of errno */
+#include	<stdarg.h>		/* ANSI C header file */
+#include	"apue.h"
+
+static void	err_doit(int, const char *, va_list);
+
+char	*pname = NULL;		/* caller can set this from argv[0] */
+
+/* Nonfatal error related to a system call.
+ * Print a message and return. */
+
+void
+err_ret(const char *fmt, ...)
+{
+	va_list		ap;
+
+	va_start(ap, fmt);
+	err_doit(1, fmt, ap);
+	va_end(ap);
+	return;
+}
+
+/* Fatal error related to a system call.
+ * Print a message and terminate. */
+
+void
+err_sys(const char *fmt, ...)
+{
+	va_list		ap;
+
+	va_start(ap, fmt);
+	err_doit(1, fmt, ap);
+	va_end(ap);
+	exit(1);
+}
+
+/* Fatal error related to a system call.
+ * Print a message, dump core, and terminate. */
+
+void
+err_dump(const char *fmt, ...)
+{
+	va_list		ap;
+
+	va_start(ap, fmt);
+	err_doit(1, fmt, ap);
+	va_end(ap);
+	abort();		/* dump core and terminate */
+	exit(1);		/* shouldn't get here */
+}
+
+/* Nonfatal error unrelated to a system call.
+ * Print a message and return. */
+
+void
+err_msg(const char *fmt, ...)
+{
+	va_list		ap;
+
+	va_start(ap, fmt);
+	err_doit(0, fmt, ap);
+	va_end(ap);
+	return;
+}
+
+/* Fatal error unrelated to a system call.
+ * Print a message and terminate. */
+
+void
+err_quit(const char *fmt, ...)
+{
+	va_list		ap;
+
+	va_start(ap, fmt);
+	err_doit(0, fmt, ap);
+	va_end(ap);
+	exit(1);
+}
+
+/* Print a message and return to caller.
+ * Caller specifies "errnoflag". */
+
+static void
+err_doit(int errnoflag, const char *fmt, va_list ap)
+{
+	int		errno_save;
+	char	buf[MAXLINE];
+
+	errno_save = errno;		/* value caller might want printed */
+	vsprintf(buf, fmt, ap);
+	if (errnoflag)
+		sprintf(buf+strlen(buf), ": %s", strerror(errno_save));
+	strcat(buf, "\n");
+	fflush(stdout);		/* in case stdout and stderr are the same */
+	fputs(buf, stderr);
+	fflush(stderr);		/* SunOS 4.1.* doesn't grok NULL argument */
+	return;
+}