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author | H. Peter Anvin <hpa@zytor.com> | 2010-02-01 15:41:43 -0800 |
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committer | H. Peter Anvin <hpa@zytor.com> | 2010-02-01 15:41:43 -0800 |
commit | 1e96e9cc1c3549c86dbf4e7caf880477e16e93e0 (patch) | |
tree | 7993bfc3c81f4253247e07587d61399466c69880 /utils | |
parent | b8a9a8c9c928fe76feb2ed0cd0eee6275623fa5a (diff) | |
download | syslinux-1e96e9cc1c3549c86dbf4e7caf880477e16e93e0.tar.gz |
mkdiskimage: add option -s to make a sparse imagesyslinux-3.85-pre4
It is often fine to have a sparse file for the output image, so add an
-s option to generate a sparse image.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'utils')
-rw-r--r-- | utils/mkdiskimage.in | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/utils/mkdiskimage.in b/utils/mkdiskimage.in index 9231fa21..533193a1 100644 --- a/utils/mkdiskimage.in +++ b/utils/mkdiskimage.in @@ -2,7 +2,7 @@ ## ----------------------------------------------------------------------- ## ## Copyright 2002-2008 H. Peter Anvin - All Rights Reserved -## Copyright 2009 Intel Corporation; author: H. Peter Anvin +## Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin ## ## This program is free software; you can redistribute it and/or modify ## it under the terms of the GNU General Public License as published by @@ -144,6 +144,7 @@ if ( $file eq '' || $c < 1 || $h < 1 || $h > 256 || $s < 1 || $s > 63 ) { print STDERR " -z use zipdisk geometry (h=64 s=32)\n"; 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"; exit 1; } @@ -216,13 +217,16 @@ print OUTPUT "\x55\xaa"; $totalsize = $c*$h*$s; $tracks = $c*$h; -$track = "\0" x (512*$s); +# If -s is given, try to simply use truncate... +unless ($opt{'s'} && truncate(OUTPUT, $totalsize)) { + $track = "\0" x (512*$s); -# Print fractional track -print OUTPUT "\0" x (512 * ($s-1)); + # Print fractional track + print OUTPUT "\0" x (512 * ($s-1)); -for ( $i = 1 ; $i < $tracks ; $i++ ) { - print OUTPUT $track; + for ( $i = 1 ; $i < $tracks ; $i++ ) { + print OUTPUT $track; + } } # Print mtools temp file |