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pax_global_header 0000666 0000000 0000000 00000000064 11205152243 0014505 g ustar 00root root 0000000 0000000 52 comment=7bdeaffcb57283afaa4a4bb6af7f2d43ede4468c
chunkfs-0.4/ 0000755 0000000 0000000 00000000000 11205152243 0013007 5 ustar 00root root 0000000 0000000 chunkfs-0.4/COPYING 0000644 0000000 0000000 00000043103 11205152243 0014043 0 ustar 00root root 0000000 0000000 GNU GENERAL PUBLIC LICENSE
Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
Preamble
The licenses for most software are designed to take away your
freedom to share and change it. By contrast, the GNU General Public
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software--to make sure the software is free for all its users. This
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the GNU Lesser General Public License instead.) You can apply it to
your programs, too.
When we speak of free software, we are referring to freedom, not
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To protect your rights, we need to make restrictions that forbid
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We protect your rights with two steps: (1) copyright the software, and
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GNU GENERAL PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License applies to any program or other work which contains
a notice placed by the copyright holder saying it may be distributed
under the terms of this General Public License. The "Program", below,
refers to any such program or work, and a "work based on the Program"
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either verbatim or with modifications and/or translated into another
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the term "modification".) Each licensee is addressed as "you".
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is covered only if its contents constitute a work based on the
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Whether that is true depends on what the Program does.
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and give any other recipients of the Program a copy of this License
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You may charge a fee for the physical act of transferring a copy, and
you may at your option offer warranty protection in exchange for a fee.
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c) If the modified program normally reads commands interactively
when run, you must cause it, when started running for such
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announcement including an appropriate copyright notice and a
notice that there is no warranty (or else, saying that you provide
a warranty) and that users may redistribute the program under
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License. (Exception: if the Program itself is interactive but
does not normally print such an announcement, your work based on
the Program is not required to print an announcement.)
These requirements apply to the modified work as a whole. If
identifiable sections of that work are not derived from the Program,
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In addition, mere aggregation of another work not based on the Program
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NO WARRANTY
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FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
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END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.
<one line to give the program's name and a brief idea of what it does.>
Copyright (C) <year> <name of author>
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
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
Also add information on how to contact you by electronic and paper mail.
If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) year name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License. Of course, the commands you use may
be called something other than `show w' and `show c'; they could even be
mouse-clicks or menu items--whatever suits your program.
You should also get your employer (if you work as a programmer) or your
school, if any, to sign a "copyright disclaimer" for the program, if
necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.
<signature of Ty Coon>, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating your program into
proprietary programs. If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library. If this is what you want to do, use the GNU Lesser General
Public License instead of this License.
chunkfs-0.4/INSTALL 0000644 0000000 0000000 00000000247 11205152243 0014043 0 ustar 00root root 0000000 0000000
You need to have libfuse >= 2.5 installed, plus perl for the build process,
at least if you want to have a man page.
Then, a simple make && make install should do.
chunkfs-0.4/Makefile 0000644 0000000 0000000 00000001337 11205152243 0014453 0 ustar 00root root 0000000 0000000
PREFIX?=/usr/local
VERSION=0.4
CFLAGS=-std=c99 -O2 -Wall
LDFLAGS=-lfuse
all: chunkfs unchunkfs chunkfs.1.gz
install:
install chunkfs ${DESTDIR}${PREFIX}/bin/
install unchunkfs ${DESTDIR}${PREFIX}/bin/
install -d ${DESTDIR}${PREFIX}/share/doc/chunkfs/examples/
install writeoverlay.sh ${DESTDIR}${PREFIX}/share/doc/chunkfs/examples/
install -m 644 chunkfs.1.gz ${DESTDIR}${PREFIX}/share/man/man1/
ln -s chunkfs.1.gz ${DESTDIR}${PREFIX}/share/man/man1/unchunkfs.1.gz
clean:
-rm chunkfs.o unchunkfs.o utils.o chunkfs unchunkfs chunkfs.1.gz
chunkfs: chunkfs.o utils.o
unchunkfs: unchunkfs.o utils.o
chunkfs.1.gz: manpage.pod
pod2man -c '' -n CHUNKFS -r 'ChunkFS ${VERSION}' -s 1 $< | gzip > $@
.PHONY: all install clean
chunkfs-0.4/chunkfs.c 0000644 0000000 0000000 00000012411 11205152243 0014613 0 ustar 00root root 0000000 0000000 /*
* ChunkFS - mount arbitrary files via FUSE as a tree of chunk files
* Copyright (C) 2007 Florian Zumbiehl <florz@florz.de>
*
* 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
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#define _FILE_OFFSET_BITS 64
#define _XOPEN_SOURCE 500
#define FUSE_USE_VERSION 25
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <limits.h>
#include <stdint.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <syslog.h>
#include <stdbool.h>
#include <sys/ioctl.h>
#include <linux/fs.h>
#include <fuse.h>
#include "utils.h"
struct chunk_stat {
int level;
mode_t mode;
off_t chunk,offset,size;
};
static int image_fd;
static off_t chunk_size,image_size,image_chunks;
#define cons_hexdig(a,b,c) { \
uint64_t t; \
if((c)>='0'&&(c)<='9'){ \
t=(c)-'0'; \
}else if((c)>='a'&&(c)<='f'){ \
t=(c)-'a'+10; \
}else{ \
return -ENOENT; \
} \
a|=t<<(b); \
}
static int resolve_path(const char *path,struct chunk_stat *st){
size_t l;
uint64_t r;
l=strlen(path);
r=0;
if(l<3||l>8*3||l%3){
if(strcmp(path,"/"))return -ENOENT;
}else{
for(int x=0;x<l/3;x++){
if(path[x*3]!='/')return -ENOENT;
cons_hexdig(r,(8-x)*8-4,path[x*3+1]);
cons_hexdig(r,(8-x)*8-8,path[x*3+2]);
}
if(r>=(uint64_t)image_chunks)return -ENOENT;
}
st->level=l/3;
st->chunk=r;
st->offset=st->chunk*chunk_size;
if(st->level<8){
st->mode=S_IFDIR;
}else{
st->mode=S_IFREG;
st->size=min(image_size-st->offset,chunk_size);
}
return 0;
}
static int chunkfs_getattr(const char *path,struct stat *buf){
int r;
struct chunk_stat st;
if((r=resolve_path(path,&st))<0)return r;
if(fstat(image_fd,buf)<0)return -errno;
buf->st_mode=(buf->st_mode&~(S_IFMT|S_IXUSR|S_IXGRP|S_IXOTH))|(st.mode&S_IFMT);
if(S_ISDIR(st.mode)){
buf->st_mode=buf->st_mode
|((buf->st_mode&S_IRUSR)?S_IXUSR:0)
|((buf->st_mode&S_IRGRP)?S_IXGRP:0)
|((buf->st_mode&S_IROTH)?S_IXOTH:0);
buf->st_nlink=256+2;
buf->st_size=0;
}else{
buf->st_nlink=1;
buf->st_size=st.size;
}
buf->st_blocks=0;
return 0;
}
static int chunkfs_readdir(const char *path,void *buf,fuse_fill_dir_t filler,off_t offset,struct fuse_file_info *fi){
int r;
struct chunk_stat st;
uint64_t chunks_per_entry;
if((r=resolve_path(path,&st))<0)return r;
if(!S_ISDIR(st.mode))return -ENOTDIR;
chunks_per_entry=1ULL<<((8-1-st.level)*8);
filler(buf,".",NULL,0);
filler(buf,"..",NULL,0);
for(uint64_t x=0;x<256&&(uint64_t)st.chunk+x*chunks_per_entry<(uint64_t)image_chunks;x++){
char nbuf[3];
sprintf(nbuf,"%02llx",x);
filler(buf,nbuf,NULL,0);
}
return 0;
}
static int chunkfs_open(const char *path,struct fuse_file_info *fi){
int r;
struct chunk_stat st;
if((r=resolve_path(path,&st))<0)return r;
if((fi->flags&O_ACCMODE)!=O_RDONLY)return -EROFS;
return 0;
}
static int chunkfs_read(const char *path,char *buf,size_t count,off_t offset,struct fuse_file_info *fi){
int r;
struct chunk_stat st;
ssize_t bufpos,r2;
if((r=resolve_path(path,&st))<0)return r;
if(S_ISDIR(st.mode))return -EISDIR;
if(count>INT_MAX)die(false,"read request larger than can be represented in an int");
if(count>SSIZE_MAX)die(false,"read request larger than can be represented in an ssize_t");
count=min((off_t)count,max(st.size-offset,(off_t)0));
for(bufpos=0;bufpos<count;){
if((r2=pread(image_fd,buf+bufpos,count-bufpos,st.offset+offset+(off_t)bufpos))<0)return -errno;
if(!r2)return -EIO;
bufpos+=r2;
}
return bufpos;
}
static struct fuse_operations chunkfs_ops={
.getattr=chunkfs_getattr,
.readdir=chunkfs_readdir,
.open=chunkfs_open,
.read=chunkfs_read
};
int main(int argc,char **argv){
struct stat st;
char opt,*end;
char *helpargv[2]={NULL,"-h"};
openlog("chunkfs",LOG_CONS|LOG_NDELAY|LOG_PERROR|LOG_PID,LOG_DAEMON);
opterr=0;
while((opt=getopt(argc,argv,"ho:"))!=-1)
if(opt=='h'){
helpargv[0]=argv[0];
return fuse_main(2,helpargv,NULL);
}
if(argc-optind!=3)die(false,"Usage: %s [options] <chunk size> <image file> <mount point>",*argv);
errno=0;
chunk_size=strtoll(argv[optind],&end,10);
if(errno||*end||chunk_size<1)die(false,"Specified invalid chunk size");
if((image_fd=open(argv[optind+1],O_RDONLY))<0)die(true,"open(image)");
if(fstat(image_fd,&st)<0)die(true,"stat(image)");
if(S_ISBLK(st.st_mode)){
uint64_t blksize;
if(ioctl(image_fd,BLKGETSIZE64,&blksize)<0)die(true,"ioctl(image,BLKGETSIZE64)");
if(blksize>(uint64_t)INT64_MAX)die(false,"block device too large");
image_size=blksize;
}else{
image_size=st.st_size;
}
image_chunks=image_size/chunk_size;
if(image_size%chunk_size)image_chunks++;
argv[optind]=argv[optind+2];
argc-=2;
return fuse_main(argc,argv,&chunkfs_ops);
}
chunkfs-0.4/debian/ 0000755 0000000 0000000 00000000000 11205152243 0014231 5 ustar 00root root 0000000 0000000 chunkfs-0.4/debian/changelog 0000644 0000000 0000000 00000001127 11205152243 0016104 0 ustar 00root root 0000000 0000000 chunkfs (0.4) unstable; urgency=low
* fixed read errors being ignored because of size_t being used where
ssize_t should be
-- Florian Zumbiehl <florz@florz.de> Wed, 23 Jul 2008 10:18:36 +0200
chunkfs (0.3) unstable; urgency=low
* Added writeoverlay.sh
-- Florian Zumbiehl <florz@florz.de> Thu, 5 Jul 2007 03:48:03 +0200
chunkfs (0.2) unstable; urgency=low
* Added UnChunkFS
-- Florian Zumbiehl <florz@florz.de> Wed, 27 Jun 2007 00:08:38 +0200
chunkfs (0.1) unstable; urgency=low
* Initial release
-- Florian Zumbiehl <florz@florz.de> Mon, 20 Jun 2007 18:29:09 +0200
chunkfs-0.4/debian/compat 0000644 0000000 0000000 00000000002 11205152243 0015427 0 ustar 00root root 0000000 0000000 5
chunkfs-0.4/debian/control 0000644 0000000 0000000 00000001467 11205152243 0015644 0 ustar 00root root 0000000 0000000 Source: chunkfs
Section: unknown
Priority: extra
Maintainer: Florian Zumbiehl <florz@florz.de>
Build-Depends: debhelper (>= 5), libfuse-dev (>= 2.5), perl
Standards-Version: 3.7.2
Package: chunkfs
Architecture: any
Depends: ${shlibs:Depends}, fuse-utils
Description: Mount arbitrary files via FUSE as a tree of chunk files.
ChunkFS allows you to mount an arbitrary file or block device as a directory
tree of read-only files that each represent a chunk of user-specified size
of the mounted file.
.
A possible use for this is space-efficient incremental backups of
encrypted filesystem images using rsync's --link-dest option.
.
The package also contains UnChunkFs, which allows you to mount a
ChunkFS tree as an image file that mirrors the contents of whatever
file or device the ChunkFS tree was created from.
chunkfs-0.4/debian/copyright 0000644 0000000 0000000 00000001734 11205152243 0016171 0 ustar 00root root 0000000 0000000
ChunkFS - mount arbitrary files via FUSE as a tree of chunk files
Copyright (C) 2007 Florian Zumbiehl <florz@florz.de>
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
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
On Debian systems, the complete text of the GNU General Public
License, version 2, can be found in /usr/share/common-licenses/GPL-2.
chunkfs-0.4/debian/dirs 0000644 0000000 0000000 00000000033 11205152243 0015111 0 ustar 00root root 0000000 0000000 usr/bin
usr/share/man/man1
chunkfs-0.4/debian/rules 0000755 0000000 0000000 00000002372 11205152243 0015315 0 ustar 00root root 0000000 0000000 #!/usr/bin/make -f
# -*- makefile -*-
# Sample debian/rules that uses debhelper.
# This file was originally written by Joey Hess and Craig Small.
# As a special exception, when this file is copied by dh-make into a
# dh-make output file, you may use that output file without restriction.
# This special exception was added by Craig Small in version 0.37 of dh-make.
# Uncomment this to turn on verbose mode.
#export DH_VERBOSE=1
configure: configure-stamp
configure-stamp:
dh_testdir
touch configure-stamp
build: build-stamp
build-stamp: configure-stamp
dh_testdir
$(MAKE)
touch $@
clean:
dh_testdir
dh_testroot
rm -f build-stamp configure-stamp
-$(MAKE) clean
dh_clean
install: build
dh_testdir
dh_testroot
dh_clean -k
dh_installdirs
$(MAKE) DESTDIR=$(CURDIR)/debian/chunkfs PREFIX=/usr install
# Build architecture-independent files here.
binary-indep: build install
# We have nothing to do by default.
# Build architecture-dependent files here.
binary-arch: build install
dh_testdir
dh_testroot
dh_installchangelogs
dh_installdocs
dh_strip
dh_compress
dh_fixperms
dh_installdeb
dh_shlibdeps
dh_gencontrol
dh_md5sums
dh_builddeb
binary: binary-indep binary-arch
.PHONY: build clean binary-indep binary-arch binary install configure
chunkfs-0.4/manpage.pod 0000644 0000000 0000000 00000012646 11205152243 0015134 0 ustar 00root root 0000000 0000000
=head1 NAME
chunkfs - mount arbitrary files via FUSE as a tree of chunk files
=head1 SYNOPSIS
B<chunkfs> { B<-h> | <I<chunk size>> <I<image file>> <I<mount point>> }
B<unchunkfs> { B<-h> | <I<chunk dir>> <I<mount point>> }
=head1 DESCRIPTION
ChunkFS allows you to mount an arbitrary file or block device as a directory
tree of read-only files that each represent a chunk of user-specified size
of the mounted file.
A possible use for this is space-efficient incremental backups of encrypted
filesystem images using rsync's --link-dest option. That way you can create
incremental backups from the ChunkFS-mounted image where any chunk that hasn't
changed since the last backup will be a hard link to the corresponding chunk
from the previous backup. In order to restore a revision, you simply have to
concatenate all the chunks from the backup. Or you could use UnCunkFS to mount
a ChunkFS tree (or a copy of one) as an image file.
<I<chunk size>> is the size of the chunks into which <I<image file>> is to be
divided when mounted at <I<mount point>>, specified in bytes. If the mounted
file's size is not a multiple of the <I<chunk size>>, the last file in the tree
simply will be smaller than the chunk size.
In case of UnChunkFS, <I<chunk dir>> is the directory that contains a ChunkFS
tree (or a copy of one) that is to be mounted at <I<mount point>>.
The chunk files of a ChunkFS are always at the eightth level of the mounted
directory tree, if there are any (that is: if the image file is at least one
byte in size). The concatenation of the path components from the root of the
filesystem to a file gives you the hexadecimal representation of the number
of the chunk that can be found in that respective file. This layout allows
you to even incrementally backup files that have changed in size, as long
as you do mount the ChunkFS with the same chunk size.
Note, however, that ChunkFS does not cope well with image files that change
their size while they are mounted. It shouldn't crash, but you will not be able
to access any newly-allocated space and you will immediately hit end of file,
or maybe even get other errors, if you try to read from a chunk file for which
there is no data in the image file anymore.
With UnChunkFS, you will always have exactly one file below the mount point,
named B<image>.
The permissions of the files within the ChunkFS are derived from the
permissions of the image file. Owner and group are simply inherited.
The mode of all objects is the same as that of the image file, except that
any executable bits are cleared for files, while directories have their
executable bits set for exactly those entities (owner, group, others)
that also have read permission. In the same way, UnChunkFS derives
ownership and permissions for its root directory and the image file
from the root of the mounted ChunkFS tree. But see below for what all
these permissions actually effect.
=head1 OPTIONS
Actually, there are quite a few options provided by the FUSE
library. For most of those, I don't even know what they do and there doesn't
seem to be any documentation. If you run chunkfs with the B<-h> option,
you will get a list of those options. Don't get confused by the fact
that the FUSE library also tells you a synopsis that contradicts what's
stated in this man page--I simply don't know how to stop libfuse from
telling you that nonsense.
Note that, by default, the permissions described above are used for
presentation only, not for actual permission checking. You might
want to use B<╜o default_permissions> to change that, and maybe
B<-o allow_other> to actually allow others to access your ChunkFS
mount.
=head1 EXAMPLES
chunkfs 1048576 supersecretcryptoimage forbackup
This gives you 1 MiB chunks of supersecretcryptoimage mounted below
forbackup.
unchunkfs forbackup forrestore
mount -o loop forrestore/image gimmebackmydata
When it's time for a restore.
chunkfs 1 /dev/hda myharddiskinpieces
You always wanted to examine every byte on your hard disk individually,
right?
If you want to use (Un)ChunkFS with block device snapshots, you
might anticipate the problem that the snapshot of a journalling filesystem
usually will need a log replay before it can be mounted--but you can't
do any log replay on a read-only image like that provided by UnChunkFS,
of course. As a possible solution, there is a B<writeoverlay.sh> script
included in this package's documentation directory that allows you to
create from an arbitrary read-only block device a writable one by the
means of the Linux device mapper's snapshot facility. Any writes to that
device will be redirected to a temporary file. Make sure you read at the
very least the comments within the script before you use it, as I
wouldn't consider it production quality.
=head1 COPYRIGHT
Copyright (C) 2007 Florian Zumbiehl <florz@florz.de>
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
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
chunkfs-0.4/unchunkfs.c 0000644 0000000 0000000 00000012705 11205152243 0015164 0 ustar 00root root 0000000 0000000 /*
* ChunkFS - mount arbitrary files via FUSE as a tree of chunk files
* Copyright (C) 2007 Florian Zumbiehl <florz@florz.de>
*
* 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
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#define _FILE_OFFSET_BITS 64
#define _XOPEN_SOURCE 500
#define FUSE_USE_VERSION 25
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <limits.h>
#include <stdint.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <syslog.h>
#include <stdbool.h>
#include <sys/ioctl.h>
#include <linux/fs.h>
#include <fuse.h>
#include "utils.h"
static int chunkdir_fd;
static off_t chunk_size,image_size;
static int ensure_chunkdir_is_cwd(){
static bool done;
if(!done){
if(fchdir(chunkdir_fd)<0)return -errno;
done=true;
}
return 0;
}
static int resolve_path(const char *path,mode_t *mode){
if(!strcmp(path,"/")){
*mode=S_IFDIR;
}else if(!strcmp(path,"/image")){
*mode=S_IFREG;
}else{
return -ENOENT;
}
return 0;
}
static void gen_chunk_name(char *buf,off_t num){
sprintf(buf+7,"%016llx",num);
for(int x=0;x<7;x++){
memmove(buf+x*3,buf+7+x*2,2);
buf[x*3+2]='/';
}
}
static int unchunkfs_getattr(const char *path,struct stat *buf){
int r;
mode_t mode;
if((r=resolve_path(path,&mode))<0)return r;
if(fstat(chunkdir_fd,buf)<0)return -errno;
buf->st_mode=(buf->st_mode&~(S_IFMT|S_IXUSR|S_IXGRP|S_IXOTH))|(mode&S_IFMT);
if(S_ISDIR(mode)){
buf->st_mode=buf->st_mode
|((buf->st_mode&S_IRUSR)?S_IXUSR:0)
|((buf->st_mode&S_IRGRP)?S_IXGRP:0)
|((buf->st_mode&S_IROTH)?S_IXOTH:0);
buf->st_nlink=2;
buf->st_size=0;
}else{
buf->st_nlink=1;
buf->st_size=image_size;
}
buf->st_blocks=0;
return 0;
}
static int unchunkfs_readdir(const char *path,void *buf,fuse_fill_dir_t filler,off_t offset,struct fuse_file_info *fi){
int r;
mode_t mode;
if((r=resolve_path(path,&mode))<0)return r;
if(!S_ISDIR(mode))return -ENOTDIR;
filler(buf,".",NULL,0);
filler(buf,"..",NULL,0);
filler(buf,"image",NULL,0);
return 0;
}
static int unchunkfs_open(const char *path,struct fuse_file_info *fi){
int r;
mode_t mode;
if((r=resolve_path(path,&mode))<0)return r;
if((fi->flags&O_ACCMODE)!=O_RDONLY)return -EROFS;
return 0;
}
static int unchunkfs_read(const char *path,char *buf,size_t count,off_t offset,struct fuse_file_info *fi){
int r,chunk_fd;
mode_t mode;
off_t chunk_num,chunk_offset;
char chunk_name[24];
ssize_t bufpos,r2;
if(ensure_chunkdir_is_cwd()<0)return -EIO;
if((r=resolve_path(path,&mode))<0)return r;
if(S_ISDIR(mode))return -EISDIR;
if(count>INT_MAX)die(false,"read request larger than can be represented in an int");
if(count>SSIZE_MAX)die(false,"read request larger than can be represented in an ssize_t");
count=min((off_t)count,max(image_size-offset,(off_t)0));
for(bufpos=0;bufpos<count;){
chunk_num=(offset+(off_t)bufpos)/chunk_size;
chunk_offset=(offset+(off_t)bufpos)%chunk_size;
gen_chunk_name(chunk_name,chunk_num);
if((chunk_fd=open(chunk_name,O_RDONLY))<0)return -EIO;
if((r2=pread(chunk_fd,buf+bufpos,count-bufpos,chunk_offset))<0)return -errno;
if(!r2)return -EIO;
bufpos+=r2;
if(close(chunk_fd)<0)die(true,"close(chunk_fd)");
}
return bufpos;
}
static struct fuse_operations unchunkfs_ops={
.getattr=unchunkfs_getattr,
.readdir=unchunkfs_readdir,
.open=unchunkfs_open,
.read=unchunkfs_read
};
int main(int argc,char **argv){
char opt;
char *helpargv[2]={NULL,"-h"};
int cwd_fd;
struct stat st;
off_t last_chunk,last_chunk_size;
openlog("unchunkfs",LOG_CONS|LOG_NDELAY|LOG_PERROR|LOG_PID,LOG_DAEMON);
opterr=0;
while((opt=getopt(argc,argv,"ho:"))!=-1)
if(opt=='h'){
helpargv[0]=argv[0];
return fuse_main(2,helpargv,NULL);
}
if(argc-optind!=2)die(false,"Usage: %s [options] <chunk dir> <mount point>",*argv);
if((cwd_fd=open(".",O_RDONLY))<0)die(true,"open(.)");
if((chunkdir_fd=open(argv[optind],O_RDONLY))<0)die(true,"open(<chunk dir>)");
if(fchdir(chunkdir_fd)<0)die(true,"fchdir(<chunk dir>)");
last_chunk=0;
last_chunk_size=0;
for(int x=64;x--;){
off_t new_last_chunk;
char chunk_name[24];
new_last_chunk=last_chunk|(x<63?(off_t)1<<x:0);
gen_chunk_name(chunk_name,new_last_chunk);
if(stat(chunk_name,&st)<0){
if(errno!=ENOENT)die(true,"stat(<chunk dir>/%s)",chunk_name);
}else{
if(st.st_size<1)die(false,"<chunk dir>/%s is smaller than one byte",chunk_name);
if(!chunk_size)chunk_size=st.st_size;
last_chunk=new_last_chunk;
last_chunk_size=st.st_size;
}
}
if(chunk_size<1)chunk_size=1;
if(last_chunk>ANYSINT_MAX(off_t)/chunk_size)die(false,"the sum of the chunks is too large");
image_size=last_chunk*chunk_size;
if(last_chunk_size>ANYSINT_MAX(off_t)-image_size)die(false,"the sum of the chunks is too large");
image_size+=last_chunk_size;
argv[optind]=argv[optind+1];
argc--;
if(fchdir(cwd_fd)<0)die(true,"fchdir(<start cwd>)");
return fuse_main(argc,argv,&unchunkfs_ops);
}
chunkfs-0.4/utils.c 0000644 0000000 0000000 00000000546 11205152243 0014320 0 ustar 00root root 0000000 0000000
#include <stdio.h>
#include <stdarg.h>
#include <syslog.h>
#include <stdlib.h>
#include "utils.h"
void die(bool syserr,const char *fmt,...){
va_list ap;
char buf[1024];
va_start(ap,fmt);
vsnprintf(buf,sizeof(buf),fmt,ap);
buf[sizeof(buf)-1]=0;
if(syserr)syslog(LOG_ERR,"%s: %m, exiting",buf);
else syslog(LOG_ERR,"%s, exiting",buf);
exit(1);
}
chunkfs-0.4/utils.h 0000644 0000000 0000000 00000000420 11205152243 0014314 0 ustar 00root root 0000000 0000000
#include <limits.h>
#include <stdbool.h>
#define min(a,b) (((a)<(b))?(a):(b))
#define max(a,b) (((a)>(b))?(a):(b))
#define ANYSINT_MAX(t) ((((t)1<<(sizeof(t)*CHAR_BIT-2))-(t)1)*(t)2+(t)1)
void die(bool,const char *,...) __attribute__ ((noreturn,format (printf,2,3)));
chunkfs-0.4/writeoverlay.sh 0000755 0000000 0000000 00000004502 11205152243 0016103 0 ustar 00root root 0000000 0000000 #!/bin/sh
#
# Copyright (C) 2007 Florian Zumbiehl <florz@florz.de>
#
# 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
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program 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.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
#
# !!! Be warned that this script isn't very sophisticated in terms of !!!
# !!! error handling and the handling of special characters in arguments! !!!
#
# This script allows you to create from an arbitrary block device a
# writable clone by the means of the Linux device mapper's snapshot
# facilities. Any writes to the clone will be stored in a temporary file.
#
# The primary intended use for this is to allow for read-only filesystem
# images (like from backups) to be mounted, even if they need some form
# of recovery, like a log replay in case of a journalling filesystem.
# That's a common problem if the image was created from a block device
# snapshot of a live filesystem.
#
# If the image is a regular file, you'll first have to create a loop
# device from that, and then use this script on that loop device.
#
set -e
#set -x
usage(){
echo usage: $0 '[ create <origdev> <cowsize> <cow_sect_per_chunk> <mapper_dev_name> | remove <mapper_dev_name> ]'
exit 1
}
case "$1" in
create)
[ $# -eq 5 ] || usage
ORIGDEV=$2
COWSIZE=$3
SECT_PER_CHUNK=$4
OVERLAYDEV=$5
COWFILE=`mktemp -t writeoverlay.XXXXXXXXXX`
dd if=/dev/zero bs=1 seek=$COWSIZE count=1 of=$COWFILE > /dev/null
LOOPDEV=`losetup -f`
losetup $LOOPDEV $COWFILE
rm $COWFILE
echo "0 `blockdev --getsz $ORIGDEV` snapshot $ORIGDEV $LOOPDEV n $SECT_PER_CHUNK" | dmsetup create $OVERLAYDEV
;;
remove)
[ $# -eq 2 ] || usage
OVERLAYDEV=$2
LOOPDEV=/dev/loop`dmsetup table $OVERLAYDEV | cut '-d ' -f5 | cut -d: -f2`
dmsetup remove $OVERLAYDEV
losetup -d $LOOPDEV
;;
*)
usage
;;
esac