script: Correct -F in man page and usage string.

Sponsored by:	Klara, Inc.
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D37138

(cherry picked from commit 8e096e24d4)

script: Add usage string for playback mode.

Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D37138

(cherry picked from commit e7c13cf438)

script: Use size_t / ssize_t where needed.

Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D37177

(cherry picked from commit 3276866f40)

script: Further usage string nits.

Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D37177

(cherry picked from commit 6ac087cf8f)

script: Handle a missing 's' stamp gracefully.

Sponsored by:	Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D37182

(cherry picked from commit 473e9fcab4)

usr.bin/script/script.1

@@ -28,7 +28,7 @@
 .\"	@(#)script.1	8.1 (Berkeley) 6/6/93
 .\" $FreeBSD$
 .\"
-.Dd March 9, 2022
+.Dd October 26, 2022
 .Dt SCRIPT 1
 .Os
 .Sh NAME
@@ -36,8 +36,7 @@
 .Nd make typescript of terminal session
 .Sh SYNOPSIS
 .Nm
-.Op Fl aefkqr
-.Op Fl F Ar pipe
+.Op Fl aeFfkqr
 .Op Fl t Ar time
 .Op Ar file Op Ar command ...
 .Nm
@@ -88,7 +87,7 @@ Accepted for compatibility with
 .Nm .
 The child command exit status is always the exit status of
 .Nm .
-.It Fl F Ar pipe
+.It Fl F
 Immediately flush output after each write.
 This will allow a user to create a named pipe using
 .Xr mkfifo 1

usr.bin/script/script.c

@@ -73,8 +73,8 @@ struct stamp {
 
 struct buf_elm {
 	TAILQ_ENTRY(buf_elm) link;
-	int rpos;
-	int len;
+	size_t rpos;
+	size_t len;
 	char ibuf[];
 };
 
@@ -107,7 +107,6 @@ static void usage(void);
 int
 main(int argc, char *argv[])
 {
-	int cc;
 	struct termios rtt, stt;
 	struct winsize win;
 	struct timeval tv, *tvp;
@@ -116,6 +115,7 @@ main(int argc, char *argv[])
 	char ibuf[BUFSIZ];
 	fd_set rfd, wfd;
 	struct buf_elm *be;
+	ssize_t cc;
 	int aflg, Fflg, kflg, pflg, ch, k, n, fcm;
 	int flushtime, readstdin;
 	int fm_fd, fm_log;
@@ -366,7 +366,9 @@ static void
 usage(void)
 {
 	(void)fprintf(stderr,
-	    "usage: script [-adfkpqr] [-t time] [file [command ...]]\n");
+	    "usage: script [-aeFfkpqr] [-t time] [file [command ...]]\n");
+	(void)fprintf(stderr,
+	    "       script -p [-deq] [-T fmt] [file]\n");
 	exit(1);
 }
 
@@ -550,6 +552,8 @@ playback(FILE *fp)
 		tclock = stamp.scr_sec;
 		tso.tv_sec = stamp.scr_sec;
 		tso.tv_nsec = stamp.scr_usec * 1000;
+		if (nread == 0)
+			tsi = tso;
 
 		switch (stamp.scr_direction) {
 		case 's':