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package Fuse; |
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|
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use 5.006; |
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use strict; |
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use warnings; |
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use Errno; |
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use Carp; |
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use Config; |
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|
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require Exporter; |
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require DynaLoader; |
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use AutoLoader; |
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use Data::Dumper; |
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our @ISA = qw(Exporter DynaLoader); |
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|
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# Items to export into callers namespace by default. Note: do not export |
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# names by default without a very good reason. Use EXPORT_OK instead. |
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# Do not simply export all your public functions/methods/constants. |
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|
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# This allows declaration use Fuse ':all'; |
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# If you do not need this, moving things directly into @EXPORT or @EXPORT_OK |
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# will save memory. |
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our %EXPORT_TAGS = ( |
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'all' => [ qw(XATTR_CREATE XATTR_REPLACE) ], |
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'xattr' => [ qw(XATTR_CREATE XATTR_REPLACE) ] |
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); |
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|
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our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } ); |
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|
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our @EXPORT = (); |
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our $VERSION = '0.07_4'; |
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|
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sub AUTOLOAD { |
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# This AUTOLOAD is used to 'autoload' constants from the constant() |
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# XS function. If a constant is not found then control is passed |
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# to the AUTOLOAD in AutoLoader. |
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|
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my $constname; |
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our $AUTOLOAD; |
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($constname = $AUTOLOAD) =~ s/.*:://; |
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croak "& not defined" if $constname eq 'constant'; |
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my $val = constant($constname, @_ ? $_[0] : 0); |
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if ($! != 0) { |
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if ($!{EINVAL}) { |
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$AutoLoader::AUTOLOAD = $AUTOLOAD; |
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goto &AutoLoader::AUTOLOAD; |
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} |
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else { |
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croak "Your vendor has not defined Fuse macro $constname"; |
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} |
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} |
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{ |
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no strict 'refs'; |
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# Fixed between 5.005_53 and 5.005_61 |
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if ($] >= 5.00561) { |
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*$AUTOLOAD = sub () { $val }; |
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} |
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else { |
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*$AUTOLOAD = sub { $val }; |
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} |
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} |
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goto &$AUTOLOAD; |
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} |
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|
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sub XATTR_CREATE { |
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# See <sys/xattr.h>. |
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return 1; |
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} |
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|
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sub XATTR_REPLACE { |
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# See <sys/xattr.h>. |
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return 2; |
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} |
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|
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bootstrap Fuse $VERSION; |
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|
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sub main { |
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my @names = qw(getattr readlink getdir mknod mkdir unlink rmdir symlink |
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rename link chmod chown truncate utime open read write statfs |
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flush release fsync setxattr getxattr listxattr removexattr); |
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my @subs = map {undef} @names; |
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my @validOpts = qw(ro allow_other default_permissions fsname use_ino nonempty); |
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my $tmp = 0; |
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my %mapping = map { $_ => $tmp++ } @names; |
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my %optmap = map { $_ => 1 } @validOpts; |
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my @otherargs = qw(debug threaded mountpoint mountopts); |
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my %otherargs = (debug=>0, threaded=>0, mountpoint=>"", mountopts=>""); |
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while(my $name = shift) { |
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my ($subref) = shift; |
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if(exists($otherargs{$name})) { |
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$otherargs{$name} = $subref; |
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} else { |
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croak "There is no function $name" unless exists($mapping{$name}); |
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croak "Usage: Fuse::main(getattr => \"main::my_getattr\", ...)" unless $subref; |
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$subs[$mapping{$name}] = $subref; |
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} |
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} |
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foreach my $opt ( map {m/^([^=]*)/; $1} split(/,/,$otherargs{mountopts}) ) { |
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next if exists($optmap{$opt}); |
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croak "Fuse::main: invalid '$opt' argument in mountopts"; |
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} |
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if($otherargs{threaded}) { |
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# make sure threads are both available, and loaded. |
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if($Config{useithreads}) { |
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if(exists($threads::{VERSION})) { |
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if(exists($threads::shared::{VERSION})) { |
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# threads will work. |
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} else { |
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carp("Thread support requires you to use threads::shared.\nThreads are disabled.\n"); |
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$otherargs{threaded} = 0; |
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} |
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} else { |
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carp("Thread support requires you to use threads and threads::shared.\nThreads are disabled.\n"); |
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$otherargs{threaded} = 0; |
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} |
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} else { |
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carp("Thread support was not compiled into this build of perl.\nThreads are disabled.\n"); |
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$otherargs{threaded} = 0; |
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} |
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} |
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perl_fuse_main(@otherargs{@otherargs},@subs); |
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} |
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|
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# Autoload methods go after =cut, and are processed by the autosplit program. |
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|
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1; |
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__END__ |
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|
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=head1 NAME |
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|
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Fuse - write filesystems in Perl using FUSE |
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|
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=head1 SYNOPSIS |
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|
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use Fuse; |
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my ($mountpoint) = ""; |
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$mountpoint = shift(@ARGV) if @ARGV; |
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Fuse::main(mountpoint=>$mountpoint, getattr=>"main::my_getattr", getdir=>"main::my_getdir", ...); |
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|
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=head1 DESCRIPTION |
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|
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This lets you implement filesystems in perl, through the FUSE |
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(Filesystem in USErspace) kernel/lib interface. |
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|
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FUSE expects you to implement callbacks for the various functions. |
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|
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In the following definitions, "errno" can be 0 (for a success), |
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-EINVAL, -ENOENT, -EONFIRE, any integer less than 1 really. |
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|
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You can import standard error constants by saying something like |
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"use POSIX qw(EDOTDOT ENOANO);". |
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|
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Every constant you need (file types, open() flags, error values, |
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etc) can be imported either from POSIX or from Fcntl, often both. |
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See their respective documentations, for more information. |
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|
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=head2 EXPORTED SYMBOLS |
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|
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None by default. |
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|
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You can request all exportable symbols by using the tag ":all". |
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|
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You can request the extended attribute symbols by using the tag ":xattr". |
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This will export XATTR_CREATE and XATTR_REPLACE. |
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|
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=head2 FUNCTIONS |
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|
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=head3 Fuse::main |
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|
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Takes arguments in the form of hash key=>value pairs. There are |
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many valid keys. Most of them correspond with names of callback |
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functions, as described in section 'FUNCTIONS YOUR FILESYSTEM MAY IMPLEMENT'. |
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A few special keys also exist: |
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|
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|
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debug => boolean |
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|
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=over 1 |
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|
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This turns FUSE call tracing on and off. Default is 0 (which means off). |
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|
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=back |
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|
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mountpoint => string |
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|
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=over 1 |
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|
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The point at which to mount this filesystem. There is no default, you must |
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specify this. An example would be '/mnt'. |
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|
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=back |
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|
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mountopts => string |
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|
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=over 1 |
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|
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This is a comma seperated list of mount options to pass to the FUSE kernel |
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module. |
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|
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At present, it allows the specification of the allow_other |
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argument when mounting the new FUSE filesystem. To use this, you will also |
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need 'user_allow_other' in /etc/fuse.conf as per the FUSE documention |
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|
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mountopts => "allow_other" or |
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mountopts => "" |
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|
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=back |
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|
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threaded => boolean |
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|
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=over 1 |
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|
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This turns FUSE multithreading on and off. The default is 0, meaning your FUSE |
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script will run in single-threaded mode. Note that single-threaded mode also |
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means that you will not have to worry about reentrancy, though you will have to |
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worry about recursive lookups. In single-threaded mode, FUSE holds a global |
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lock on your filesystem, and will wait for one callback to return before |
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calling another. This can lead to deadlocks, if your script makes any attempt |
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to access files or directories in the filesystem it is providing. (This |
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includes calling stat() on the mount-point, statfs() calls from the 'df' |
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command, and so on and so forth.) It is worth paying a little attention and |
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being careful about this. |
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|
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Enabling multithreading will cause FUSE to make multiple simultaneous calls |
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into the various callback functions of your perl script. If you enable |
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threaded mode, you can enjoy all the parallel execution and interactive |
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response benefits of threads, and you get to enjoy all the benefits of race |
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conditions and locking bugs, too. Please also ensure any other perl modules |
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you're using are also thread-safe. |
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|
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(If enabled, this option will cause a warning if your perl interpreter was not |
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built with USE_ITHREADS, or if you have failed to use threads or |
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threads::shared.) |
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|
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=back |
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|
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=head2 FUNCTIONS YOUR FILESYSTEM MAY IMPLEMENT |
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|
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=head3 getattr |
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|
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Arguments: filename. |
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Returns a list, very similar to the 'stat' function (see |
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perlfunc). On error, simply return a single numeric scalar |
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value (e.g. "return -ENOENT();"). |
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|
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FIXME: the "ino" field is currently ignored. I tried setting it to 0 |
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in an example script, which consistently caused segfaults. |
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|
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Fields (the following was stolen from perlfunc(1) with apologies): |
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|
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($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size, |
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$atime,$mtime,$ctime,$blksize,$blocks) |
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= getattr($filename); |
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|
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Here are the meaning of the fields: |
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|
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0 dev device number of filesystem |
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1 ino inode number |
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2 mode file mode (type and permissions) |
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3 nlink number of (hard) links to the file |
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4 uid numeric user ID of file's owner |
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5 gid numeric group ID of file's owner |
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6 rdev the device identifier (special files only) |
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7 size total size of file, in bytes |
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8 atime last access time in seconds since the epoch |
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9 mtime last modify time in seconds since the epoch |
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10 ctime inode change time (NOT creation time!) in seconds |
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since the epoch |
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11 blksize preferred block size for file system I/O |
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12 blocks actual number of blocks allocated |
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|
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(The epoch was at 00:00 January 1, 1970 GMT.) |
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|
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=head3 readlink |
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|
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Arguments: link pathname. |
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Returns a scalar: either a numeric constant, or a text string. |
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|
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This is called when dereferencing symbolic links, to learn the target. |
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|
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example rv: return "/proc/self/fd/stdin"; |
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|
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=head3 getdir |
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|
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Arguments: Containing directory name. |
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Returns a list: 0 or more text strings (the filenames), followed by a numeric errno (usually 0). |
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|
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This is used to obtain directory listings. Its opendir(), readdir(), filldir() and closedir() all in one call. |
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|
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example rv: return ('.', 'a', 'b', 0); |
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|
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=head3 mknod |
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|
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Arguments: Filename, numeric modes, numeric device |
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Returns an errno (0 upon success, as usual). |
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|
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This function is called for all non-directory, non-symlink nodes, |
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not just devices. |
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|
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=head3 mkdir |
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|
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Arguments: New directory pathname, numeric modes. |
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Returns an errno. |
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|
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Called to create a directory. |
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|
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=head3 unlink |
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|
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Arguments: Filename. |
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Returns an errno. |
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|
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Called to remove a file, device, or symlink. |
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|
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=head3 rmdir |
315 |
|
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Arguments: Pathname. |
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Returns an errno. |
318 |
|
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Called to remove a directory. |
320 |
|
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=head3 symlink |
322 |
|
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Arguments: Existing filename, symlink name. |
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Returns an errno. |
325 |
|
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Called to create a symbolic link. |
327 |
|
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=head3 rename |
329 |
|
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Arguments: old filename, new filename. |
331 |
Returns an errno. |
332 |
|
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Called to rename a file, and/or move a file from one directory to another. |
334 |
|
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=head3 link |
336 |
|
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Arguments: Existing filename, hardlink name. |
338 |
Returns an errno. |
339 |
|
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Called to create hard links. |
341 |
|
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=head3 chmod |
343 |
|
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Arguments: Pathname, numeric modes. |
345 |
Returns an errno. |
346 |
|
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Called to change permissions on a file/directory/device/symlink. |
348 |
|
349 |
=head3 chown |
350 |
|
351 |
Arguments: Pathname, numeric uid, numeric gid. |
352 |
Returns an errno. |
353 |
|
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Called to change ownership of a file/directory/device/symlink. |
355 |
|
356 |
=head3 truncate |
357 |
|
358 |
Arguments: Pathname, numeric offset. |
359 |
Returns an errno. |
360 |
|
361 |
Called to truncate a file, at the given offset. |
362 |
|
363 |
=head3 utime |
364 |
|
365 |
Arguments: Pathname, numeric actime, numeric modtime. |
366 |
Returns an errno. |
367 |
|
368 |
Called to change access/modification times for a file/directory/device/symlink. |
369 |
|
370 |
=head3 open |
371 |
|
372 |
Arguments: Pathname, numeric flags (which is an OR-ing of stuff like O_RDONLY |
373 |
and O_SYNC, constants you can import from POSIX). |
374 |
Returns an errno. |
375 |
|
376 |
No creation, or trunctation flags (O_CREAT, O_EXCL, O_TRUNC) will be passed to open(). |
377 |
Your open() method needs only check if the operation is permitted for the given flags, and return 0 for success. |
378 |
|
379 |
=head3 read |
380 |
|
381 |
Arguments: Pathname, numeric requestedsize, numeric offset. |
382 |
Returns a numeric errno, or a string scalar with up to $requestedsize bytes of data. |
383 |
|
384 |
Called in an attempt to fetch a portion of the file. |
385 |
|
386 |
=head3 write |
387 |
|
388 |
Arguments: Pathname, scalar buffer, numeric offset. You can use length($buffer) to |
389 |
find the buffersize. |
390 |
Returns an errno. |
391 |
|
392 |
Called in an attempt to write (or overwrite) a portion of the file. Be prepared because $buffer could contain random binary data with NULLs and all sorts of other wonderful stuff. |
393 |
|
394 |
=head3 statfs |
395 |
|
396 |
Arguments: none |
397 |
Returns any of the following: |
398 |
|
399 |
-ENOANO() |
400 |
|
401 |
or |
402 |
|
403 |
$namelen, $files, $files_free, $blocks, $blocks_avail, $blocksize |
404 |
|
405 |
or |
406 |
|
407 |
-ENOANO(), $namelen, $files, $files_free, $blocks, $blocks_avail, $blocksize |
408 |
|
409 |
=head3 flush |
410 |
|
411 |
Arguments: Pathname |
412 |
Returns an errno or 0 on success. |
413 |
|
414 |
Called to synchronise any cached data. This is called before the file |
415 |
is closed. It may be called multiple times before a file is closed. |
416 |
|
417 |
=head3 release |
418 |
|
419 |
Arguments: Pathname, numeric flags passed to open |
420 |
Returns an errno or 0 on success. |
421 |
|
422 |
Called to indicate that there are no more references to the file. Called once |
423 |
for every file with the same pathname and flags as were passed to open. |
424 |
|
425 |
=head3 fsync |
426 |
|
427 |
Arguments: Pathname, numeric flags |
428 |
Returns an errno or 0 on success. |
429 |
|
430 |
Called to synchronise the file's contents. If flags is non-zero, |
431 |
only synchronise the user data. Otherwise synchronise the user and meta data. |
432 |
|
433 |
=head3 setxattr |
434 |
|
435 |
Arguments: Pathname, extended attribute's name, extended attribute's value, numeric flags (which is an OR-ing of XATTR_CREATE and XATTR_REPLACE |
436 |
Returns an errno or 0 on success. |
437 |
|
438 |
Called to set the value of the named extended attribute. |
439 |
|
440 |
If you wish to reject setting of a particular form of extended attribute name |
441 |
(e.g.: regexps matching user\..* or security\..*), then return - EOPNOTSUPP. |
442 |
|
443 |
If flags is set to XATTR_CREATE and the extended attribute already exists, |
444 |
this should fail with - EEXIST. If flags is set to XATTR_REPLACE |
445 |
and the extended attribute doesn't exist, this should fail with - ENOATTR. |
446 |
|
447 |
XATTR_CREATE and XATTR_REPLACE are provided by this module, but not exported |
448 |
by default. To import them: |
449 |
|
450 |
use Fuse ':xattr'; |
451 |
|
452 |
or: |
453 |
|
454 |
use Fuse ':all'; |
455 |
|
456 |
=head3 getxattr |
457 |
|
458 |
Arguments: Pathname, extended attribute's name |
459 |
Returns an errno, 0 if there was no value, or the extended attribute's value. |
460 |
|
461 |
Called to get the value of the named extended attribute. |
462 |
|
463 |
=head3 listxattr |
464 |
|
465 |
Arguments: Pathname |
466 |
Returns a list: 0 or more text strings (the extended attribute names), followed by a numeric errno (usually 0). |
467 |
|
468 |
=head3 removexattr |
469 |
|
470 |
Arguments: Pathname, extended attribute's name |
471 |
Returns an errno or 0 on success. |
472 |
|
473 |
=head1 AUTHOR |
474 |
|
475 |
Mark Glines, E<lt>mark@glines.orgE<gt> |
476 |
|
477 |
=head1 SEE ALSO |
478 |
|
479 |
L<perl>, the FUSE documentation. |
480 |
|
481 |
=cut |