Syslinux - Jan 2014 - [PATCH 03/05] utils/mkdiskimage.in: Replaced the partly linux-specific file size determination by a sysseek() experiment

utils/mkdiskimage.in: With option -s: Avoid zeroizing the partition even if
truncate() failed.

--- utils/mkdiskimage_patched_01.in	2014-01-30 20:43:02.000000000 +0100
+++ utils/mkdiskimage.in	2014-01-30 20:45:09.000000000 +0100
@@ -217,8 +217,11 @@ print OUTPUT "\x55\xaa";
 $totalsize = $c*$h*$s;
 $tracks    = $c*$h;
 
-# If -s is given, try to simply use truncate...
-unless ($opt{'s'} && truncate(OUTPUT, $totalsize * 512)) {
+# If -s is given, simply use truncate. Do not care for success. Failure is
+# normal with Linux block devices.
+if ($opt{'s'}) {
+    truncate(OUTPUT, $totalsize * 512);
+} else {
     $track = "\0" x (512*$s);
 
     # Print fractional track

utils/mkdiskimage.in: Replaced the partly linux-specific file size determination
by a sysseek() experiment.

--- utils/mkdiskimage_patched_02.in	2014-01-30 20:49:46.000000000 +0100
+++ utils/mkdiskimage.in	2014-01-30 20:50:59.000000000 +0100
@@ -19,6 +19,7 @@
 use bytes;
 use integer;
 use Fcntl;
+use Fcntl qw(:seek);
 use Errno;
 use Cwd;
 use IO::Handle;			# For flush()
@@ -116,15 +117,8 @@ if ( $c == 0 && $file ne '' ) {
     $len = 0;
     if ( sysopen(OUTPUT, $file, O_RDWR, 0666) ) {
 	$is_open = 1;
-
-	if ( (@filestat = stat(OUTPUT)) && S_ISREG($filestat[2]) ) {
-	    $len = $filestat[7] >> 9;
-	} elsif ( $is_linux && S_ISBLK($filestat[2]) ) {
-	    $blksize = pack("L!", 0);
-	    if ( ioctl(OUTPUT, $BLKGETSIZE, $blksize) == 0 ) {
-		$len = unpack("L!", $blksize); # In 512-byte sectors!
-	    }
-	}
+	$len = sysseek(OUTPUT, 0, SEEK_END) >> 9;
+	sysseek(OUTPUT, 0, SEEK_SET);
     }
 
     if ( !$len ) {

utils/mkdiskimage.in: New option -S to sync zeroizing after each cylinder and to
issue pacifier messages.

--- utils/mkdiskimage_patched_03.in	2014-01-30 20:54:27.000000000 +0100
+++ utils/mkdiskimage.in	2014-01-30 20:59:19.000000000 +0100
@@ -139,6 +139,7 @@ if ( $file eq '' || $c < 1 || $h < 1 || 
     print STDERR "    -4    use partition entry 4 (standard for
zipdisks)\n";
     print STDERR "    -i    specify the MBR ID\n";
     print STDERR "    -s    output a sparse file (don't allocate all
blocks)\n";
+    print STDERR "    -S    sync after each zeroized cylinder and show
count\n";
     exit 1;
 }
 
@@ -218,12 +219,24 @@ if ($opt{'s'}) {
 } else {
     $track = "\0" x (512*$s);
 
+    $show_pacifier = $opt{'S'};
+
     # Print fractional track
     print OUTPUT "\0" x (512 * ($s-1));
 
     for ( $i = 1 ; $i < $tracks ; $i++ ) {
+	if ( $show_pacifier && ( $i - 1 ) % $h == 0 ) {
+	    $cyl_to_write = ( $i - 1 ) / $h + 1;
+	    IO::Handle::sync(OUTPUT);
+	    print STDERR " zeroizing cylinder $cyl_to_write of $c\r";
+	}
 	print OUTPUT $track;
     }
+    if ( $show_pacifier ) {
+	IO::Handle::sync(OUTPUT);
+	$zeroized = $totalsize + $zero_tail - 1;
+	print STDERR " $zeroized blocks zeroized.              \n";
+    }
 }
 
 # Print mtools temp file