scriptreplay: rewrite in C

The dependence on Perl sucks...

Co-Author: James Youngman <jay@gnu.org>
Signed-off-by: Karel Zak <kzak@redhat.com>
Signed-off-by: James Youngman <jay@gnu.org>

4 files changed, 215 insertions, 93 deletions

diff --git a/misc-utils/Makefile.am b/misc-utils/Makefile.am
index 5441b0157..40610c142 100644
--- a/misc-utils/Makefile.am
+++ b/misc-utils/Makefile.am
@@ -5,14 +5,14 @@ EXTRA_DIST = README.flushb
 bin_PROGRAMS =
 
 usrbinexec_PROGRAMS = cal ddate logger look mcookie \
-	namei script whereis
+	namei script whereis scriptreplay
 EXTRA_DIST += README.cal README.ddate README.namei README.namei2
 
 mcookie_SOURCES = mcookie.c ../lib/md5.c
 
-usrbinexec_SCRIPTS = chkdupexe scriptreplay
+usrbinexec_SCRIPTS = chkdupexe
 
-CLEANFILES = chkdupexe scriptreplay
+CLEANFILES = chkdupexe
 
 dist_man_MANS = cal.1 chkdupexe.1 ddate.1 logger.1 look.1 mcookie.1 \
 	namei.1 script.1 whereis.1 scriptreplay.1
diff --git a/misc-utils/scriptreplay.1 b/misc-utils/scriptreplay.1
index 98129fb4a..b2a03a242 100644
--- a/misc-utils/scriptreplay.1
+++ b/misc-utils/scriptreplay.1
@@ -149,8 +149,18 @@ scriptreplay timingfile [typescript [divisor]]
 .IX Header "DESCRIPTION"
 This program replays a typescript, using timing information to ensure that
 output happens at the same speed as it originally appeared when the script
-was recorded. It is only guaranteed to work properly if run on the same
-terminal the script was recorded on.
+was recorded.
+.PP
+The replay simply displays the information again; the programs
+that were run when the typescript was being recorded are not run again.
+Since the same information is simply being displayed,
+.B scriptreplay
+is only guaranteed to work properly if run on the same type of
+terminal the typescript was recorded on.  Otherwise, any escape characters
+in the typescript may be interpreted differently by the terminal to
+which
+.B scriptreplay
+is sending its output.
 .PP
 The timings information is what script outputs to standard error if it is
 run with the \-t parameter.
@@ -158,8 +168,11 @@ run with the \-t parameter.
 By default, the typescript to display is assumed to be named \*(L"typescript\*(R",
 but other filenames may be specified, as the second parameter.
 .PP
-If the third parameter exits, it is used as a time divisor. For example,
-specifying a divisor of 2 makes the script be replayed twice as fast.
+If the third parameter is specified, it is used as a speed-up multiplier. For
+example, a speed-up of 2 makes
+.B scriptreplay
+go twice as fast and a speed-up of 0.1 makes it go ten times slower
+than the original session.
 .SH "EXAMPLE"
 .IX Header "EXAMPLE"
 .Vb 7
@@ -176,10 +189,23 @@ specifying a divisor of 2 makes the script be replayed twice as fast.
 .BR script (1)
 .SH "COPYRIGHT"
 .IX Header "COPYRIGHT"
-This program is in the public domain.
+Copyright \(co 2008 James Youngman
+.PP
+Copyright \(co 2008 Karel Zak
+.PP
+This is free software; see the source for copying conditions.  There is NO
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
+PURPOSE.
+.PP
+Released under the GNU General Public License version 2 or later.
 .SH "AUTHOR"
 .IX Header "AUTHOR"
-Joey Hess <joey@kitenet.net>
+The original
+.B scriptreplay
+program was written by Joey Hess <joey@kitenet.net>.
+The program was re-written in C by James Youngman <jay@gnu.org> and Karel Zak <kzak@redhat.com>.
 .SH AVAILABILITY
-The scriptreplay command is part of the util-linux-ng package and is available from
+The
+.B scriptreplay
+command is part of the util-linux-ng package and is available from
 ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
diff --git a/misc-utils/scriptreplay.c b/misc-utils/scriptreplay.c
new file mode 100644
index 000000000..2ae31a2a7
--- /dev/null
+++ b/misc-utils/scriptreplay.c
@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2008, Karel Zak <kzak@redhat.com>
+ * Copyright (C) 2008, James Youngman <jay@gnu.org>
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This file is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ *
+ * Based on scriptreplay.pl by Joey Hess <joey@kitenet.net>
+ */
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+#include <limits.h>
+#include <math.h>
+#include <sys/select.h>
+#include <unistd.h>
+#include <err.h>
+
+#include "nls.h"
+
+#define SCRIPT_MIN_DELAY 0.0001		/* from original sripreplay.pl */
+
+void __attribute__((__noreturn__))
+usage(int rc)
+{
+	printf("%s <timingfile> [<typescript> [<divisor>]]\n",
+			program_invocation_short_name);
+	exit(rc);
+}
+
+static double
+getnum(const char *s)
+{
+	double d;
+	char *end;
+
+	errno = 0;
+	d = strtod(s, &end);
+
+	if (end && *end != '\0')
+		errx(EXIT_FAILURE, _("expected a number, but got '%s'"), s);
+
+	if ((d == HUGE_VAL || d == -HUGE_VAL) && ERANGE == errno)
+		err(EXIT_FAILURE, _("divisor '%s'"), s);
+
+	if (!(d==d)) { /* did they specify "nan"? */
+		errno = EINVAL;
+		err(EXIT_FAILURE, _("divisor '%s'"), s);
+	}
+	return d;
+}
+
+static void
+delay_for(double delay)
+{
+#ifdef HAVE_NANOSLEEP
+	struct timespec ts, remainder;
+	ts.tv_sec = (time_t) delay;
+	ts.tv_nsec = (delay - ts.tv_sec) * 1.0e9;
+
+	while (-1 == nanosleep(&ts, &remainder)) {
+		if (EINTR == errno)
+			ts = remainder;
+		else
+			break;
+	}
+#else
+	struct timeval tv;
+	tv.tv_sec = (long) delay;
+	tv.tv_usec = (delay - tv.tv_sec) * 1.0e6;
+	select(0, NULL, NULL, NULL, &tv);
+#endif
+}
+
+static void
+emit(FILE *fd, const char *filename, size_t ct)
+{
+	char buf[BUFSIZ];
+
+	while(ct) {
+		size_t len, cc;
+
+		cc = ct > sizeof(buf) ? sizeof(buf) : ct;
+		len = fread(buf, 1, cc, fd);
+
+		if (!len)
+		       break;
+
+		ct -= len;
+		cc = write(STDOUT_FILENO, buf, len);
+		if (cc != len)
+			err(EXIT_FAILURE, "write to stdout failed");
+	}
+
+	if (!ct)
+		return;
+	if (feof(fd))
+		errx(EXIT_FAILURE, _("unexpected end of file on %s"), filename);
+
+	err(EXIT_FAILURE, _("failed to read typescript file %s"), filename);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+	FILE *tfile, *sfile;
+	const char *sname, *tname;
+	double divi;
+	int c;
+	unsigned long line;
+
+	/* Because we use space as a separator, we can't afford to use any
+	 * locale which tolerates a space in a number.  In any case, script.c
+	 * sets the LC_NUMERIC locale to C, anyway.
+	 */
+	setlocale(LC_ALL, "");
+	setlocale(LC_NUMERIC, "C");
+
+	bindtextdomain(PACKAGE, LOCALEDIR);
+	textdomain(PACKAGE);
+
+	if (argc < 2 && argc > 4)
+		usage(EXIT_FAILURE);
+
+	tname = argv[1];
+	sname = argc > 2 ? argv[2] : "typescript";
+	divi = argc == 4 ? getnum(argv[3]) : 1;
+
+	tfile = fopen(tname, "r");
+	if (!tfile)
+		err(EXIT_FAILURE, _("cannot open timing file %s"), tname);
+	sfile = fopen(sname, "r");
+	if (!sfile)
+		err(EXIT_FAILURE, _("cannot open typescript file %s"), sname);
+
+	/* ignore the first typescript line */
+	while((c = fgetc(sfile)) != EOF && c != '\n');
+
+	for(line = 0; ; line++) {
+		double delay;
+		size_t blk;
+		char nl;
+
+		if ((fscanf(tfile, "%lf %zd%[\n]\n", &delay, &blk, &nl) != 3) ||
+							(nl != '\n')) {
+			if (feof(tfile))
+				break;
+			if (ferror(tfile))
+				err(EXIT_FAILURE,
+					"failed to read timing file %s", tname);
+			errx(EXIT_FAILURE,
+				_("timings file %s: %lu: expected format"),
+				tname, line);
+		}
+		delay /= divi;
+
+		if (delay > SCRIPT_MIN_DELAY)
+			delay_for(delay);
+
+		emit(sfile, sname, blk);
+	}
+
+	fclose(sfile);
+	fclose(tfile);
+	exit(EXIT_SUCCESS);
+}
diff --git a/misc-utils/scriptreplay.pl b/misc-utils/scriptreplay.pl
deleted file mode 100755
index b445f6d61..000000000
--- a/misc-utils/scriptreplay.pl
+++ /dev/null
@@ -1,83 +0,0 @@
-#!@PERL@ -w
-
-# "script -t" will output a typescript with timings
-# this script "scriptreplay" replays it
-# run pod2man on it to get a man page
-
-=head1 NAME
-
-scriptreplay - play back typescripts, using timing information
-
-=head1 SYNOPSIS
-
-scriptreplay timingfile [typescript [divisor]]
-
-=head1 DESCRIPTION
-
-This program replays a typescript, using timing information to ensure that
-output happens at the same speed as it originally appeared when the script
-was recorded. It is only guaranteed to work properly if run on the same
-terminal the script was recorded on.
-
-The timings information is what script outputs to standard error if it is
-run with the -t parameter.
-
-By default, the typescript to display is assumed to be named "typescript",
-but other filenames may be specified, as the second parameter.
-
-If the third parameter exits, it is used as a time divisor. For example,
-specifying a divisor of 2 makes the script be replayed twice as fast.
-
-=head1 EXAMPLE
-
- % script -t 2> timingfile
- Script started, file is typescript
- % ls
- <etc, etc>
- % exit
- Script done, file is typescript
- % scriptreplay timingfile
-
-=cut
-
-use strict;
-$|=1;
-open (TIMING, shift)
-        or die "cannot read timing info: $!";
-open (TYPESCRIPT, shift || 'typescript')
-        or die "cannot read typescript: $!";
-my $divisor=shift || 1;
-
-# Read starting timestamp line and ignore.
-<TYPESCRIPT>;
-
-my $block;
-my $oldblock='';
-while (<TIMING>) {
-        my ($delay, $blocksize)=split ' ', $_, 2;
-        # Sleep, unless the delay is really tiny. Really tiny delays cannot
-        # be accurately done, because the system calls in this loop will
-        # have more overhead. The 0.0001 is arbitrary, but works fairly well.
-        if ($delay / $divisor > 0.0001) {
-                select(undef, undef, undef, $delay / $divisor - 0.0001);
-        }
-
-        read(TYPESCRIPT, $block, $blocksize)
-                or die "read failure on typescript: $!";
-        print $oldblock;
-        $oldblock=$block;
-}
-print $oldblock;
-
-=head1 SEE ALSO
-
-script(1)
-
-=head1 COPYRIGHT
-
-This program is in the public domain.
-
-=head1 AUTHOR
-
-Joey Hess <joey@kitenet.net>
-