backuppcExportOnUsbDisk/backuppcfs
2017-02-28 15:13:49 +01:00

762 lines
25 KiB
Perl
Executable file

#!/usr/bin/perl
# backuppcfs - a fuse module to access backuppc backups through the filesystem.
# Copyright (C) 2009 Pieter Wuille
# Based on the backuppc-fuse script by Stephen Day
#
# 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 3 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, see <http://www.gnu.org/licenses/>.
# Changelog:
# - 2009 Nov 10: default_permissions on by default
# - 2009 Jun 10: LRU cache to limit number of cached nodes
# - 2009 Jun 09: Correction of absolute symlinks
# - 2009 Jun 05: Errors propagate forced re-reads upwards
# - 2009 Jun 05: Support for type!=mode, hardlinks, empty files
# - 2009 Jun 03: Full directory merging (for share-directories)
# - 2009 Jun 02: Initial version
# Changes w.r.t. Stephen Day's version:
# - cached tree - huge speedup
# - support for character/blockdevices
# - correct linkcounts for directories
# - support for /'s in sharenames
# - daemonization
# - stateful open()'s to prevent seeking for every read
# - correct merged view for incremental backups
# - latest/oldest link in hosts to latest/oldest archive
# - getopt for somewhat more configurability
# - support for empty files
# - support for xfermethods that don't set filetype bits in mode, like tar
# - support for hardlinks (linkcount=1, however)
# TODO:
# - testing!
# - error output/logging
# - escaping of dangerous characters in host/sharenames
# - fsstats
# - mtime of root/hosts/links
# - forced uid/perms/umask of virtual dirs/all dirs
# - uid mapping
# - common getattr generation - a lot seems shared
# - mtime for virtual dirs (eg. most recent backup)
# - some way of finding the last/first backup before/after a given date/time?
use strict;
use Fuse;
use Fcntl ':mode';
use POSIX qw/EROFS EOPNOTSUPP ENOENT EINVAL setsid strftime/;
use Getopt::Long qw(:config permute bundling);
require Carp;
use lib "/usr/share/backuppc/lib";
use lib "/usr/share/BackupPC/lib";
use BackupPC::Lib;
use BackupPC::View;
use BackupPC::Attrib qw(:all);
my $TTL_ROOT = 80000; # don't expect new hosts within a day
my $TTL_HOST = 40000; # don't expect new archives within half a day
my $TTL_ARCHIVE = 1000000; # +- infinite timeout for archives/shares
my $TTL_SHARE = 1000000; # as as long as they exist, their content
my $TTL_REST = 1000000; # does not change
my $BLKSIZE = 512; # reasonable number - is it used for anything?
my $DEFDEV = 0;
my $DEFINODE = 1;
my $DEFUID = $<; # your uid
my ($DEFGID) = split(/ /,$(); # your gid
my $DEFPERM = 0755; # u=rwx,g=rx,o=rx (for directories)
my $CORLINKS = 0; # modify absolute symlinks to point to the archive root
my $MOUNTPOINT = undef;
my $MAXCACHE = 2048;
#my $CONF_REALINODES = 1;
#################################
########### LRU lib #############
#################################
# an LRU (least recently used) datastructure:
# a circular double-linked list, with one
# marker node (which initially refers to itself)
# the data of the marker node is a hash reference
# that maps data elements to the lru nodes containing them
# each node is [$prevRef,$data,$nextRef], while the
# marker node is [$lastRef,$hash,$firstRef]
# create a new lru data structure
sub lru_create {
my $x=[undef,{},undef];
$x->[0]=$x;
$x->[2]=$x;
return $x;
}
# delete an entry from an lru
sub lru_delete {
my ($lru,$data) = @_;
my $x = $lru->[1];
if (exists $x->{$data}) {
my $n = $x->{$data};
my $prev = $n->[0];
my $next = $n->[2];
$prev->[2] = $next;
$next->[0] = $prev;
@{$n} = ();
delete $x->{$data};
}
}
# move an entry to the end of the structure, creating it if necessary
sub lru_access {
my ($lru,$data) = @_;
my $x = $lru->[1];
my $n;
my $last;
if (defined $x->{$data}) {
$n = $x->{$data}; # find existing node
my $prev = $n->[0]; # find its predecessor/successor
my $next = $n->[2];
$prev->[2] = $next; # make them point to eachother
$next->[0] = $prev;
$last = $lru->[0];
$n->[0] = $last; # make the reused node know its new predecessor/successor
$n->[2] = $lru;
} else {
$last = $lru->[0];
$n = [$last,$data,$lru]; # create new node
$x->{$data} = $n; # add it to the hashtable
}
$last->[2] = $n; # insert the entry itself
$lru->[0] = $n;
}
# destroy a complete lru structure
sub lru_destroy {
my ($lru) = @_;
my $x = $lru;
while (defined $x->[2]) {
my $nx = $x->[2];
undef @{$x};
$x = $nx;
}
}
# retrieve the element least recently lru_access'ed
sub lru_lru {
my ($lru) = @_;
my $x = $lru->[2];
return undef if ($x == $lru);
return $x->[1];
}
# calculate the size of the lru
sub lru_size {
my ($lru) = @_;
return (0+(keys %{$lru->[1]}));
}
#################################
########## cache lib ############
#################################
# a cached array is represented as an array reference containing:
# - a function reference to call when the data has expired
# - a scalar to pass to the function
# - a ttl value (in seconds)
# - an expiration time (seconds sinds epoch when current value expires, -1 if certainly/already expired)
# - ref to the cached array
# if a cache has subentries, these must be the values of a hash, referenced by the first value returned
my $cachelru = lru_create();
my %cachefn;
# create a cached value (function ref,data,ttl)
sub cache_create {
my ($fn,$data,$ttl) = @_;
my @ret = ($fn,$data,$ttl,-1,undef);
return \@ret;
}
sub cache_evict {
my ($cache) = @_;
if (defined $cache->[2] && defined $cache->[4]) {
lru_delete($cachelru,$cache);
}
if (defined $cache->[4]) {
my $d = $cache->[4];
if (defined $d->[0]) {
foreach my $x (values %{$d->[0]}) {
cache_evict($x);
}
}
}
}
sub cache_purge {
while (lru_size($cachelru) > $MAXCACHE) {
my $old = lru_lru($cachelru);
cache_evict($old);
$old->[3] = -1;
$old->[4] = undef;
}
}
# read data from cache (refreshing it if necessary)
sub cache_read {
my ($cache,$force) = @_;
cache_purge;
my $nt = time;
if (defined($cache->[2]) && (defined($force) || ($cache->[3] < $nt))) {
cache_evict($cache);
my @ret;
@ret = $cachefn{$cache->[0]}->($cache->[1]);
$cache->[4] = \@ret;
$cache->[3] = $nt+$cache->[2];
}
lru_access($cachelru,$cache) if (defined($cache->[2]));
return (@{$cache->[4]});
}
# create a cached object that returns a constant array
sub cache_const {
my @val = @_;
my @ret = (undef,undef,undef,undef,\@val);
return \@ret;
}
#################################
######## tree functions #########
#################################
# the filesystem is internally represented by a (cached, see above) tree
# each node is a cached array containing these elements:
# - ref to hash containing [filename -> cached array] mappings
# - attributes (corresponding to getinfo)
# - backuppc attributes object
# - actual data (currently: link data for symlinks)
# reuse the same backuppc Lib object
my $bpc;
sub bpc {
if (!defined $bpc) {
$bpc = BackupPC::Lib->new(undef,undef,"",1);
}
return $bpc;
}
# a cache refresher that builds on top of another (directory) node, and adds some static subentries to it
sub fs_dirmerge {
my ($data) = @_;
my ($type,$sdata,$ndir,$ent) = @{$data}; # nodetype name, data for node, number of added subentries that are dirs, hashref of subentries
my ($sub,$attr,$a) = $cachefn{$type}->($sdata);
return undef if (!defined $attr);
if (S_ISDIR($attr->[2])) {
my %nsub = %{$sub};
my @nattr = @{$attr};
foreach my $k (keys %{$ent}) {
if (exists $nsub{$k}) { # a collision occurred
my ($s1sub,$s1attr,$s1a) = cache_read($ent->{$k}); # check whether entry to add is a directory
if (S_ISDIR($s1attr->[2])) {
my ($s2sub,$s2attr,$s2a) = cache_read($nsub{$k}); # check whether entry in original dir is a directory
if (S_ISDIR($s2attr->[2])) { # if so, substitute it with a new merge node
$nsub{$k} = cache_create('dirmerge',[$nsub{$k}->[0],$nsub{$k}->[1],$s1attr->[3]-2,$s1sub],$nsub{$k}->[2]);
next;
}
}
if (!exists $nsub{$k.'_'}) { # try adding '_' otherwise
$nsub{$k.'_'} = $ent->{$k};
next;
}
my $i=1;
$i++ while (exists $nsub{$k.'_'.$i}); # try adding subsequent '_<num>' otherwise
$nsub{$k.'_'.$i} = $ent->{$k};
} else {
$nsub{$k} = $ent->{$k};
}
}
$nattr[3] += $ndir;
return (\%nsub,\@nattr,$a);
} else {
Carp::croak "Unable to add subentries to a non-directory"
}
}
# the root cache refresher, no arguments
sub fs_root {
my $bpc=bpc();
return undef if (!defined $bpc);
my $hosts = $bpc->HostInfoRead();
return undef if (!defined $hosts);
my %hlist = map { ($_,cache_create('host',$_,$TTL_HOST)) } (keys %{$hosts});
return (\%hlist,[$DEFDEV,$DEFINODE,S_IFDIR | $DEFPERM,2 + keys %hlist,$DEFUID,$DEFGID,0,1024,0,0,0,$BLKSIZE,2],undef);
}
sub fmtTime {
my ($ut) = @_;
return (strftime "%Y-%m-%d %H:%M:%S", localtime $ut);
}
# the host cache refresher, arguments (host)
sub fs_host {
my ($host) = @_;
my @archives = (bpc()->BackupInfoRead($host));
return undef if ($#archives<0);
my $lnum = undef;
my $onum = undef;
my $view = BackupPC::View->new(bpc(), $host, \@archives);
return undef if (!defined $view);
my %alist = map {
$lnum=$_->{num} if (!defined($lnum) || $_->{num}>$lnum);
$onum=$_->{num} if (!defined($onum) || $_->{num}<$onum);
(
$_->{num},cache_create('archive',[$_,$view],$TTL_ARCHIVE),
fmtTime($_->{startTime}),cache_const(undef,[$DEFDEV,$DEFINODE,S_IFLNK | $DEFPERM,1,$DEFUID,$DEFGID,0,length($_->{num}),0,0,0,$BLKSIZE,0],undef,$_->{num})
)
} (@archives);
$alist{latest} = cache_const(undef,[$DEFDEV,$DEFINODE,S_IFLNK | $DEFPERM,1,$DEFUID,$DEFGID,0,length($lnum),0,0,0,$BLKSIZE,0],undef,"$lnum") if (defined($lnum));
$alist{oldest} = cache_const(undef,[$DEFDEV,$DEFINODE,S_IFLNK | $DEFPERM,1,$DEFUID,$DEFGID,0,length($onum),0,0,0,$BLKSIZE,0],undef,"$onum") if (defined($onum));
return (\%alist,[$DEFDEV,$DEFINODE,S_IFDIR | $DEFPERM,2 + @archives,$DEFUID,$DEFGID,0,1024,0,0,0,$BLKSIZE,2],undef);
}
# recursive helper function to build a tree containing all shares
sub buildtree {
my ($node,$view,$archive) = @_;
my %sub; # hash for all subdirectories
foreach my $se (keys %{$node}) {
$sub{$se} = buildtree($node->{$se},$view,$archive) if ($se ne '');
}
if (exists $node->{''}) {
my $se = [$view,$archive,$node->{''},undef,''];
return cache_create('dirmerge',['share',$se,0+(keys %sub),\%sub],$TTL_SHARE) if ((keys %sub)>0); # both a share and virtual sharename-dirs
return cache_create('share',$se,$TTL_SHARE); # only a real share
} else { # only a virtual sharename dir
my $archivetime = $archive->{startTime};
return cache_const(\%sub,[$DEFDEV,$DEFINODE,S_IFDIR | $DEFPERM,2 + keys %sub,$DEFUID,$DEFGID,0,1024,$archivetime,$archivetime,$archivetime,$BLKSIZE,2],undef);
}
}
# the archive cache refresher, arguments [archiveref,view]
sub fs_archive {
my ($data) = @_;
my ($archive,$view) = @{$data};
my $archivenum = $archive->{num};
my @shares = $view->shareList($archivenum);
return undef if ($#shares<0);
my %tree; # abstract tree - each node can have some name->subnode mappings for subdirs, and/or a '' entry referring to a share
foreach my $share (@shares) { # loop over all shares
my @path = grep { $_ ne '' && $_ ne '.' && $_ ne '..' } (split(/[\\\/]+/,$share)); # split them in pieces (both / and \ seen as separators)
my $node = \%tree; # start at the root - node is a hashref to the current treenode
while ($#path >= 0) { # while there are path components left
my $ent = shift @path; # get a component
$node->{$ent}={} if (!exists $node->{$ent}); # create empty subnode if it doesn't exist yet
$node = $node->{$ent}; # travel down
}
$node->{''} = $share; # finally make the reached leaf node point to the share (full, original share name)
}
return cache_read(buildtree(\%tree,$view,$archive)); # now call helper funtion to turn it into a tree of cached arrays and evaluate it
}
# mapping from backuppc file types to stat() file type modes
my %iftype = (
BPC_FTYPE_FILE, S_IFREG,
BPC_FTYPE_HARDLINK, S_IFLNK,
BPC_FTYPE_SYMLINK, S_IFLNK,
BPC_FTYPE_CHARDEV, S_IFCHR,
BPC_FTYPE_DIR, S_IFDIR,
BPC_FTYPE_FIFO, S_IFIFO,
BPC_FTYPE_SOCKET, S_IFSOCK,
BPC_FTYPE_UNKNOWN, 0,
BPC_FTYPE_DELETED, 0
);
# the share/backupdata cache refresher, arguments [view,archive,share,fileattr,path]
sub fs_share {
my ($data) = @_;
my ($view,$archive,$share,$a,$path) = @{$data};
my $archivenum = $archive->{num};
my $ino = $DEFINODE;
my $dev = $DEFDEV;
# if (defined($a) && $CONF_REALINODES) {
# ($dev,$ino) = stat($a->{fullPath});
# }
if (!defined($a) || $a->{type}==BPC_FTYPE_DIR) { # directory (root dir which has no $a, or subdir which does)
my $nattr = $view->dirAttrib($archivenum,$share,$path); # get attributes/list of directory entries
return undef if (!defined $nattr);
my $sdirs = 0; # number of subdirectories
my %sub = map {
my $key=$_;
my $val = $nattr->{$key};
$sdirs++ if ($val->{type}==BPC_FTYPE_DIR); # count subdirs
($key,cache_create('share',[$view,$archive,$share,$val,$path.'/'.$key],$TTL_REST))
} (keys %{$nattr});
if (!defined($a)) { # root of share
my $archivetime = $archive->{startTime};
return (\%sub,[$dev,$ino,S_IFDIR | $DEFPERM,2 + $sdirs,$DEFUID,$DEFGID,0,1024,$archivetime,$archivetime,$archivetime,$BLKSIZE,2],undef);
} else { # subdir in share
my $mtime = $a->{mtime};
my $size = ( $a->{sizeDiv4GB} * 1024 * 1024 * 1024 * 4 ) + $a->{sizeMod4GB};
my $blocks = int ( $size / 512 );
if ($size==0) { # some xfermethods don't store a meaningful size for directories
$size = 1024;
$blocks = 2;
}
return (\%sub,[$dev,$ino,S_IFDIR | ($a->{mode} & ~S_IFMT),2 + $sdirs,$a->{uid},$a->{gid},0,$size,$mtime,$mtime,$mtime,$BLKSIZE,$blocks],$a);
}
} else { # non-directory
my $mtime = $a->{mtime};
my $size = ( $a->{sizeDiv4GB} * 1024 * 1024 * 1024 * 4 ) + $a->{sizeMod4GB};
my $blocks = int ( $size / 512 );
my $rdev = 0;
my $fdata;
my $mode = ($a->{mode} & (~S_IFMT)) | $iftype{$a->{type}};
if (S_ISLNK($mode) || S_ISCHR($mode) || S_ISBLK($mode)) { # link, character or block device: read real backup data
my $f = BackupPC::FileZIO->open($a->{fullPath}, 0, $a->{compress});
return undef if (!defined $f);
$f->read(\$fdata,65536);
$f->close;
}
if ((S_ISCHR($mode) || S_ISBLK($mode)) && $fdata =~ /(\d+),(\d+)/) {
$rdev = $1*256 + $2;
}
if ($a->{type} == BPC_FTYPE_HARDLINK) {
my $sa = $view->fileAttrib($archivenum,$share,'/'.$fdata);
return undef if (!defined $sa);
return fs_share([$view,$archive,$share,$sa,$fdata]);
}
if ($a->{type} == BPC_FTYPE_SYMLINK) {
if ($CORLINKS && ((substr $fdata,0,1) eq '/')) {
$fdata = $MOUNTPOINT . '/' . $view->{host} . '/' . $archivenum . '/' . $fdata;
}
}
return (undef,[$dev,$ino,$mode,1,$a->{uid},$a->{gid},$rdev,$size,$mtime,$mtime,$mtime,$BLKSIZE,$blocks],$a,$fdata);
}
}
my $root = cache_create('root',undef,$TTL_ROOT);
%cachefn = (
root => \&fs_root,
host => \&fs_host,
archive => \&fs_archive,
share => \&fs_share,
dirmerge => \&fs_dirmerge,
);
# lookup a node in the tree
sub get_data {
my ($path) = @_;
my @path = grep { $_ ne '' && $_ ne '.' && $_ ne '..' } (split(/\/+/,$path));
my $done="";
my $node = $root;
foreach my $ent (@path) {
my ($sub,$attr) = (cache_read($node));
if (!defined $attr) { # entry itself doesn't seem te exist - cache tree is wrong
prop_failure($done);
return undef;
}
($sub)=(cache_read($node,1)) if (!defined $sub || !defined $sub->{$ent}); # requested subnode does not seem te exist - force re-read
return undef if (!defined $sub || !defined $sub->{$ent}); # it really doesn't exist
$done .= '/'.$ent;
$node = $sub->{$ent};
}
return cache_read($node);
}
# called when a particular path doesn't seem to exist anymore - forces re-evaluations until
# it finds what caused the failure
sub prop_failure {
my ($path) = @_;
my @path = grep { $_ ne '' && $_ ne '.' && $_ ne '..' } (split(/\/+/,$path)); # path components
my @node = ($root); # subsequent nodes in the (currently cached) tree
my @ent = (); # entries we'd like to exist
while (@path) {
my $ent = shift @path;
push @ent,$ent;
my ($sub,$attr) = (cache_read($node[$#node]));
last if (!defined $attr);
return if (!defined $sub);
return if (!exists $sub->{$ent});
last if (!@path);
push @node,$sub->{$ent};
}
while (@node) {
my $node = pop @node;
my $ent = pop @ent;
my ($sub,$attr) = (cache_read($node,1));
last if (!defined $ent || (defined $attr && (!defined $sub || !exists $sub->{$ent})));
}
}
#################################
######## Fuse functions #########
#################################
sub bpc_getattr {
my ($path) = @_;
my ($sub,$attr) = get_data($path);
return -ENOENT() if (!defined $attr);
return (@{$attr});
}
sub bpc_readlink {
my ($path) = @_;
my ($sub,$attr,$a,$fd) = get_data($path);
return -ENOENT() if (!defined $attr);
return -EINVAL() if (!defined $fd);
return $fd;
}
sub bpc_getdir {
my ($path) = @_;
my ($sub) = get_data($path);
return -ENOENT() if (!defined $sub);
my @list = keys %{$sub};
return ( '.', '..', @list, 0 );
}
sub bpc_rwop {
return -EROFS();
}
sub bpc_unsupp {
return -EOPNOTSUPP();
}
my %files; # pathname -> [(zio,pos)] # zio==undef means file is empty
sub bpc_open {
my ($path,$mode) = @_;
my ($sub,$attr,$a) = get_data($path);
return -ENOENT() if (!defined $attr);
my $zio;
if ($attr->[7]!=0) { # non-empty file
$zio = BackupPC::FileZIO->open($a->{fullPath}, 0, $a->{compress}); # create zio object
if (!defined $zio) {
my $err = 0-$!;
prop_failure($path);
return $err;
}
}
push @{$files{$path}},[$zio,0]; # add the zio (which now has position 0) to the list of zio's for the requested file
return 0;
}
sub bpc_release {
my ($path,$mode) = @_;
my $lastpos=-1;
my $lasti=undef;
my $lst = $files{$path};
# find zio with highest pos
foreach my $i (0..$#{$lst}) {
my $ent = $lst->[$i];
my ($zio,$pos) = @{$ent};
if ($pos>$lastpos) {
$lastpos = $pos;
$lasti = $i;
}
}
if (!defined $lasti) { # fail miserably when nothing found - this means a fuse 'release' call happened without corresponding 'open' call
Carp::croak "Closing unopened file '$path'";
}
my ($zio) = @{$lst->[$lasti]}; # retrieve that 'best' zio
$zio->close() if (defined $zio); # close it
if ($#{$lst}==0) { # remove it from the hash
delete $files{$path};
} else {
splice @{$files{$path}},$lasti,1;
}
}
sub bpc_read {
my ($path,$size,$offset) = @_;
my $bestpos=-1;
my $besti=undef;
my $lst = $files{$path};
# find zio with highest pos - if possible highest pos <= offset, otherwise highest pos whatsoever
foreach my $i (0..$#{$lst}) {
my $ent = $lst->[$i];
my ($zio,$pos) = @{$ent};
if (($pos<=$offset && ($pos>$bestpos || $bestpos>$offset)) || ($pos>$offset && $pos>$bestpos && ($bestpos>$offset || $bestpos<0))) {
$bestpos = $pos;
$besti = $i;
}
}
if (!defined $besti) { # fail miserable when nothing was found - it means fuse requested a read from an unopened file
Carp::croak "Reading from unopened file '$path'";
}
my ($zio,$pos) = @{$lst->[$besti]}; # retrieve zio object and its file position
return '' if (!defined $zio);
if ($pos>$offset) {
$zio->rewind; # rewind the zio object if it already passed the requested start position for the read
$pos=0;
}
my $data;
while ($pos<$offset) { # as long a there is unrequested data left, seek
my $do = $offset-$pos;
$do=65536 if ($do>65536);
my $ret = $zio->read(\$data,$do);
if ($ret<=0) { # upon eof, return nothing; upon error, return failure
$lst->[$besti]->[1]=$pos;
if ($ret<0) {
my $err = 0 - $!;
prop_failure($path);
return $ret;
}
return '';
}
$pos += $ret;
}
my $ret = $zio->read(\$data,$size); # do the actual read request
if ($ret<=0) { # upon eof, return nothing, upon error, return failure
$lst->[$besti]->[1]=$pos;
if ($ret<0) {
my $err = 0 - $!;
prop_failure($path);
return $ret;
}
return '';
}
$pos += $ret; # update position
$lst->[$besti]->[1]=$pos; # update position in hash
return $data; # return data
}
sub bpc_statfs {
return 0;
}
sub bpc_flush {
return 0;
}
sub bpc_fsync {
return 0;
}
#################################
############# Main ##############
#################################
my $showhelp = 0;
my $foreground = 0;
my %fuseopts = ('default_permissions');
my $ok = GetOptions(
'foreground|f!' => \$foreground,
'uid|u=i' => sub { $DEFUID = $_[1]; die "uid out of range: $_[1]" if ($DEFUID<0 || $DEFUID>65535) },
'gid|g=i' => sub { $DEFGID = $_[1]; die "gid out of range: $_[1]" if ($DEFGID<0 || $DEFGID>65535) },
'user|U=s' => sub { $DEFUID = getpwnam($_[1]); die "unknown user '$_[1]'" if (!defined $DEFUID) },
'group|G=s' => sub { $DEFGID = getgrnam($_[1]); die "unknown group '$_[1]'" if (!defined $DEFGID) },
'mode|m=o' => sub { $DEFPERM = $_[1]; die "mode out of range: $_[1]" if ($DEFPERM<0 || $DEFPERM>32767) },
'cache|c=i' => sub { $MAXCACHE = $_[1]; die "cache out of range: $_[1]" if ($MAXCACHE<32 || $MAXCACHE>1048576) },
'correct-links|l!' => \$CORLINKS,
'help|h|?' => \$showhelp,
'o=s' => sub { foreach my $opt (split /,+/,$_[1]) { if (substr($opt,0,3) eq 'no_') { delete $fuseopts{lc $opt} } else { $fuseopts{lc $opt}=1; } } },
);
if ($ok && !$showhelp) {
if ($#ARGV>=0) {
$MOUNTPOINT = shift(@ARGV) if ($#ARGV>=0);
}
$ok = 0 if (!defined $MOUNTPOINT);
}
if ($ok && !$showhelp) {
die "mountpoint '$MOUNTPOINT' if not valid" if (! -d $MOUNTPOINT);
}
if (!$ok || $showhelp) {
print "Usage: $0 [options] mountpoint\n";
print "\n";
print "Options:\n";
print " -u,--uid UID Use UID as owner of the mounted filesystem\n";
print " -U,--user USER Use USER as owner of the mounted filesystem\n";
print " -g,--gid GID Use GID as owner of the mounted filesystem\n";
print " -G,--group GROUP Use GROUP as owner of the mounted filesystem\n";
print " -m,--mode MODE Use MODE as permissions of the filesystem\n";
print " -h,--help Show this help text\n";
print " -f,--foreground Do not daemonize\n";
print " -l,--correct-links Correct absolute symlinks - mountpoint must be absolute\n";
print " -c,--cache SIZE Keep directory cache smaller than SIZE nodes\n";
print " -o OPT1[,OPT2[,...]] Fuse options\n";
print "\n";
print "FUSE options (may or may not work, depending on fuse version):\n";
print " -o allow_other allow access to other users\n";
print " -o nonempty allow mounts over non-empty file/dir\n";
print " -o no_default_permissions disable permission checking by kernel\n";
print " -o fsname=NAME set filesystem name\n";
print "\n";
print "By default you/your primary group are owners of the filesystem\n";
print "directories, using mode 0755 (owner rwx, others rx).\n";
print "Use 'fusermount -u mountpoint' to unmount.\n";
print "By daemonizing (default), no errors will be shown.\n";
exit (!$ok);
}
# daemonize
sub daemonize {
umask 0;
open STDIN, '</dev/null' or die "Can't read /dev/null: $!";
open STDOUT, '>/dev/null' or die "Can't write to /dev/null: $!";
open STDERR, '>/dev/null' or die "Can't write to /dev/null: $!";
defined(my $pid = fork) or die "Can't fork: $!";
exit if $pid;
setsid or die "Can't start a new session: $!";
}
daemonize if (!$foreground);
# run fuse
Fuse::main(
mountopts => join(',',keys %fuseopts),
mountpoint => $MOUNTPOINT,
threaded => 0,
debug => 0,
# supported operations
open=> \&bpc_open,
release=> \&bpc_release,
getattr=> \&bpc_getattr,
readlink=> \&bpc_readlink,
getdir=> \&bpc_getdir,
read=> \&bpc_read,
flush=> \&bpc_flush,
statfs=> \&bpc_statfs,
# not meaningful for read-only view
write=> \&bpc_rwop,
mknod=> \&bpc_rwop,
mkdir=> \&bpc_rwop,
unlink=> \&bpc_rwop,
rmdir=> \&bpc_rwop,
symlink=> \&bpc_rwop,
rename=> \&bpc_rwop,
link=> \&bpc_rwop,
chmod=> \&bpc_rwop,
chown=> \&bpc_rwop,
truncate=> \&bpc_rwop,
utime=> \&bpc_rwop,
fsync=> \&bpc_fsync,
# not supported
setxattr=> \&bpc_unsupp,
getxattr=> \&bpc_unsupp,
listxattr=> \&bpc_unsupp,
removexattr=> \&bpc_unsupp
);
lru_destroy($cachelru);