13 our @ISA = qw(Exporter DynaLoader);
15 # Items to export into callers namespace by default. Note: do not export
16 # names by default without a very good reason. Use EXPORT_OK instead.
17 # Do not simply export all your public functions/methods/constants.
19 # This allows declaration use Fuse ':all';
20 # If you do not need this, moving things directly into @EXPORT or @EXPORT_OK
23 'all' => [ qw(XATTR_CREATE XATTR_REPLACE fuse_get_context fuse_version FUSE_IOCTL_COMPAT FUSE_IOCTL_UNRESTRICTED FUSE_IOCTL_RETRY FUSE_IOCTL_MAX_IOV notify_poll pollhandle_destroy) ],
24 'xattr' => [ qw(XATTR_CREATE XATTR_REPLACE) ],
25 'ioctl' => [ qw(FUSE_IOCTL_COMPAT FUSE_IOCTL_UNRESTRICTED FUSE_IOCTL_RETRY FUSE_IOCTL_MAX_IOV) ],
28 our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
31 our $VERSION = '0.14';
34 # This AUTOLOAD is used to 'autoload' constants from the constant()
35 # XS function. If a constant is not found then control is passed
36 # to the AUTOLOAD in AutoLoader.
40 ($constname = $AUTOLOAD) =~ s/.*:://;
41 croak "& not defined" if $constname eq 'constant';
42 my $val = constant($constname, @_ ? $_[0] : 0);
45 $AutoLoader::AUTOLOAD = $AUTOLOAD;
46 goto &AutoLoader::AUTOLOAD;
49 croak "Your vendor has not defined Fuse macro $constname";
54 # Fixed between 5.005_53 and 5.005_61
56 *$AUTOLOAD = sub () { $val };
59 *$AUTOLOAD = sub { $val };
65 bootstrap Fuse $VERSION;
67 use constant FUSE_IOCTL_COMPAT => (1 << 0);
68 use constant FUSE_IOCTL_UNRESTRICTED => (1 << 1);
69 use constant FUSE_IOCTL_RETRY => (1 << 2);
70 use constant FUSE_IOCTL_MAX_IOV => 256;
73 my @names = qw(getattr readlink getdir mknod mkdir unlink rmdir symlink
74 rename link chmod chown truncate utime open read write statfs
75 flush release fsync setxattr getxattr listxattr removexattr);
76 my $fuse_version = fuse_version();
77 if ($fuse_version >= 2.3) {
78 push(@names, qw/opendir readdir releasedir fsyncdir init destroy/);
80 if ($fuse_version >= 2.5) {
81 push(@names, qw/access create ftruncate fgetattr/);
83 if ($fuse_version >= 2.6) {
84 push(@names, qw/lock utimens bmap/);
86 if ($fuse_version >= 2.8) {
87 # junk doesn't contain a function pointer, and hopefully
88 # never will; it's a "dead" zone in the struct
89 # fuse_operations where a flag bit is declared. we don't
90 # need to concern ourselves with it, and it appears any
91 # arch with a 64 bit pointer will align everything to
92 # 8 bytes, making the question of pointer alignment for
93 # the last 2 wrapper functions no big thing.
94 push(@names, qw/junk ioctl poll/);
96 my @subs = map {undef} @names;
98 my %mapping = map { $_ => $tmp++ } @names;
99 my @otherargs = qw(debug threaded mountpoint mountopts nullpath_ok);
107 while(my $name = shift) {
108 my ($subref) = shift;
109 if(exists($otherargs{$name})) {
110 $otherargs{$name} = $subref;
112 croak "There is no function $name" unless exists($mapping{$name});
113 croak "Usage: Fuse::main(getattr => \"main::my_getattr\", ...)" unless $subref;
114 $subs[$mapping{$name}] = $subref;
117 if($otherargs{threaded}) {
118 # make sure threads are both available, and loaded.
119 if($Config{useithreads}) {
120 if(exists($threads::{VERSION})) {
121 if(exists($threads::shared::{VERSION})) {
124 carp("Thread support requires you to use threads::shared.\nThreads are disabled.\n");
125 $otherargs{threaded} = 0;
128 carp("Thread support requires you to use threads and threads::shared.\nThreads are disabled.\n");
129 $otherargs{threaded} = 0;
132 carp("Thread support was not compiled into this build of perl.\nThreads are disabled.\n");
133 $otherargs{threaded} = 0;
136 perl_fuse_main(@otherargs{@otherargs},@subs);
139 # Autoload methods go after =cut, and are processed by the autosplit program.
146 Fuse - write filesystems in Perl using FUSE
151 my ($mountpoint) = "";
152 $mountpoint = shift(@ARGV) if @ARGV;
153 Fuse::main(mountpoint=>$mountpoint, getattr=>"main::my_getattr", getdir=>"main::my_getdir", ...);
157 This lets you implement filesystems in perl, through the FUSE
158 (Filesystem in USErspace) kernel/lib interface.
160 FUSE expects you to implement callbacks for the various functions.
162 In the following definitions, "errno" can be 0 (for a success),
163 -EINVAL, -ENOENT, -EONFIRE, any integer less than 1 really.
165 You can import standard error constants by saying something like
166 "use POSIX qw(EDOTDOT ENOANO);".
168 Every constant you need (file types, open() flags, error values,
169 etc) can be imported either from POSIX or from Fcntl, often both.
170 See their respective documentations, for more information.
172 =head2 EXPORTED SYMBOLS
176 You can request all exportable symbols by using the tag ":all".
178 You can request the extended attribute symbols by using the tag ":xattr".
179 This will export XATTR_CREATE and XATTR_REPLACE.
185 Takes arguments in the form of hash key=>value pairs. There are
186 many valid keys. Most of them correspond with names of callback
187 functions, as described in section 'FUNCTIONS YOUR FILESYSTEM MAY IMPLEMENT'.
188 A few special keys also exist:
195 This turns FUSE call tracing on and off. Default is 0 (which means off).
203 The point at which to mount this filesystem. There is no default, you must
204 specify this. An example would be '/mnt'.
212 This is a comma separated list of mount options to pass to the FUSE kernel
215 At present, it allows the specification of the allow_other
216 argument when mounting the new FUSE filesystem. To use this, you will also
217 need 'user_allow_other' in /etc/fuse.conf as per the FUSE documention
219 mountopts => "allow_other" or
228 This turns FUSE multithreading on and off. The default is 0, meaning your FUSE
229 script will run in single-threaded mode. Note that single-threaded mode also
230 means that you will not have to worry about reentrancy, though you will have to
231 worry about recursive lookups. In single-threaded mode, FUSE holds a global
232 lock on your filesystem, and will wait for one callback to return before
233 calling another. This can lead to deadlocks, if your script makes any attempt
234 to access files or directories in the filesystem it is providing. (This
235 includes calling stat() on the mount-point, statfs() calls from the 'df'
236 command, and so on and so forth.) It is worth paying a little attention and
237 being careful about this.
239 Enabling multithreading will cause FUSE to make multiple simultaneous calls
240 into the various callback functions of your perl script. If you enable
241 threaded mode, you can enjoy all the parallel execution and interactive
242 response benefits of threads, and you get to enjoy all the benefits of race
243 conditions and locking bugs, too. Please also ensure any other perl modules
244 you're using are also thread-safe.
246 (If enabled, this option will cause a warning if your perl interpreter was not
247 built with USE_ITHREADS, or if you have failed to use threads or
252 nullpath_ok => boolean
256 This flag tells Fuse to not pass paths for functions that operate on file
257 or directory handles. This will yield empty path parameters for functions
258 including read, write, flush, release, fsync, readdir, releasedir,
259 fsyncdir, truncate, fgetattr and lock. If you use this, you must return
260 file/directory handles from open, opendir and create. Default is 0 (off).
261 Only effective on Fuse 2.8 and up; with earlier versions, this does nothing.
265 =head3 Fuse::fuse_get_context
267 use Fuse "fuse_get_context";
268 my $caller_uid = fuse_get_context()->{"uid"};
269 my $caller_gid = fuse_get_context()->{"gid"};
270 my $caller_pid = fuse_get_context()->{"pid"};
272 Access context information about the current Fuse operation.
274 =head3 Fuse::fuse_version
276 Indicates the Fuse version in use; more accurately, indicates the version
277 of the Fuse API in use at build time. Returned as a decimal value; i.e.,
278 for Fuse API v2.6, will return "2.6".
280 =head3 Fuse::notify_poll
282 Only available if the Fuse module is built against libfuse 2.8 or later.
283 Use fuse_version() to determine if this is the case. Calling this function
284 with a pollhandle argument (as provided to the C<poll> operation
285 implementation) will send a notification to the caller poll()ing for
286 I/O operation availability. If more than one pollhandle is provided for
287 the same filehandle, only use the latest; you *can* send notifications
288 to them all, but it is unnecessary and decreases performance.
290 ONLY supply poll handles fed to you through C<poll> to this function.
291 Due to thread safety requirements, we can't currently package the pointer
292 up in an object the way we'd like to to prevent this situation, but your
293 filesystem server program may segfault, or worse, if you feed things to
294 this function which it is not supposed to receive. If you do anyway, we
295 take no responsibility for whatever Bad Things(tm) may happen.
297 =head3 Fuse::pollhandle_destroy
299 Only available if the Fuse module is built against libfuse 2.8 or later.
300 Use fuse_version() to determine if this is the case. This function destroys
301 a poll handle (fed to your program through C<poll>). When you are done
302 with a poll handle, either because it has been replaced, or because a
303 notification has been sent to it, pass it to this function to dispose of
306 ONLY supply poll handles fed to you through C<poll> to this function.
307 Due to thread safety requirements, we can't currently package the pointer
308 up in an object the way we'd like to to prevent this situation, but your
309 filesystem server program may segfault, or worse, if you feed things to
310 this function which it is not supposed to receive. If you do anyway, we
311 take no responsibility for whatever Bad Things(tm) may happen.
313 =head2 FUNCTIONS YOUR FILESYSTEM MAY IMPLEMENT
319 Returns a list, very similar to the 'stat' function (see
320 perlfunc). On error, simply return a single numeric scalar
321 value (e.g. "return -ENOENT();").
323 FIXME: the "ino" field is currently ignored. I tried setting it to 0
324 in an example script, which consistently caused segfaults.
326 Fields (the following was stolen from perlfunc(1) with apologies):
328 ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
329 $atime,$mtime,$ctime,$blksize,$blocks)
330 = getattr($filename);
332 Here are the meaning of the fields:
334 0 dev device number of filesystem
336 2 mode file mode (type and permissions)
337 3 nlink number of (hard) links to the file
338 4 uid numeric user ID of file's owner
339 5 gid numeric group ID of file's owner
340 6 rdev the device identifier (special files only)
341 7 size total size of file, in bytes
342 8 atime last access time in seconds since the epoch
343 9 mtime last modify time in seconds since the epoch
344 10 ctime inode change time (NOT creation time!) in seconds
346 11 blksize preferred block size for file system I/O
347 12 blocks actual number of blocks allocated
349 (The epoch was at 00:00 January 1, 1970 GMT.)
353 Arguments: link pathname.
355 Returns a scalar: either a numeric constant, or a text string.
357 This is called when dereferencing symbolic links, to learn the target.
359 example rv: return "/proc/self/fd/stdin";
363 Arguments: Containing directory name.
365 Returns a list: 0 or more text strings (the filenames), followed by a numeric errno (usually 0).
367 This is used to obtain directory listings. It's opendir(), readdir(), filldir() and closedir() all in one call.
369 example rv: return ('.', 'a', 'b', 0);
373 Arguments: Filename, numeric modes, numeric device
375 Returns an errno (0 upon success, as usual).
377 This function is called for all non-directory, non-symlink nodes,
382 Arguments: New directory pathname, numeric modes.
386 Called to create a directory.
394 Called to remove a file, device, or symlink.
402 Called to remove a directory.
406 Arguments: Existing filename, symlink name.
410 Called to create a symbolic link.
414 Arguments: old filename, new filename.
418 Called to rename a file, and/or move a file from one directory to another.
422 Arguments: Existing filename, hardlink name.
426 Called to create hard links.
430 Arguments: Pathname, numeric modes.
434 Called to change permissions on a file/directory/device/symlink.
438 Arguments: Pathname, numeric uid, numeric gid.
442 Called to change ownership of a file/directory/device/symlink.
446 Arguments: Pathname, numeric offset.
450 Called to truncate a file, at the given offset.
454 Arguments: Pathname, numeric actime, numeric modtime.
458 Called to change access/modification times for a file/directory/device/symlink.
462 Arguments: Pathname, numeric flags (which is an OR-ing of stuff like O_RDONLY
463 and O_SYNC, constants you can import from POSIX), fileinfo hash reference.
465 Returns an errno, a file handle (optional).
467 No creation, or truncation flags (O_CREAT, O_EXCL, O_TRUNC) will be passed to open().
468 The fileinfo hash reference contains flags from the Fuse open call which may be modified by the module. The only fields presently supported are:
469 direct_io (version 2.4 onwards)
470 keep_cache (version 2.4 onwards)
471 nonseekable (version 2.9 onwards)
472 Your open() method needs only check if the operation is permitted for the given flags, and return 0 for success.
473 Optionally a file handle may be returned, which will be passed to subsequent read, write, flush, fsync and release calls.
477 Arguments: Pathname, numeric requested size, numeric offset, file handle
479 Returns a numeric errno, or a string scalar with up to $requestedsize bytes of data.
481 Called in an attempt to fetch a portion of the file.
485 Arguments: Pathname, scalar buffer, numeric offset, file handle. You can use length($buffer) to
487 Returns length($buffer) if successful (number of bytes written).
489 Called in an attempt to write (or overwrite) a portion of the file. Be prepared because $buffer could contain random binary data with NULs and all sorts of other wonderful stuff.
495 Returns any of the following:
501 $namelen, $files, $files_free, $blocks, $blocks_avail, $blocksize
505 -ENOANO(), $namelen, $files, $files_free, $blocks, $blocks_avail, $blocksize
509 Arguments: Pathname, file handle
511 Returns an errno or 0 on success.
513 Called to synchronise any cached data. This is called before the file
514 is closed. It may be called multiple times before a file is closed.
518 Arguments: Pathname, numeric flags passed to open, file handle
519 Returns an errno or 0 on success.
521 Called to indicate that there are no more references to the file. Called once
522 for every file with the same pathname and flags as were passed to open.
526 Arguments: Pathname, numeric flags
528 Returns an errno or 0 on success.
530 Called to synchronise the file's contents. If flags is non-zero,
531 only synchronise the user data. Otherwise synchronise the user and meta data.
535 Arguments: Pathname, extended attribute's name, extended attribute's value, numeric flags (which is an OR-ing of XATTR_CREATE and XATTR_REPLACE
537 Returns an errno or 0 on success.
539 Called to set the value of the named extended attribute.
541 If you wish to reject setting of a particular form of extended attribute name
542 (e.g.: regexps matching user\..* or security\..*), then return - EOPNOTSUPP.
544 If flags is set to XATTR_CREATE and the extended attribute already exists,
545 this should fail with - EEXIST. If flags is set to XATTR_REPLACE
546 and the extended attribute doesn't exist, this should fail with - ENOATTR.
548 XATTR_CREATE and XATTR_REPLACE are provided by this module, but not exported
549 by default. To import them:
559 Arguments: Pathname, extended attribute's name
561 Returns an errno, 0 if there was no value, or the extended attribute's value.
563 Called to get the value of the named extended attribute.
569 Returns a list: 0 or more text strings (the extended attribute names), followed by a numeric errno (usually 0).
573 Arguments: Pathname, extended attribute's name
575 Returns an errno or 0 on success.
579 Arguments: Pathname of a directory
580 Returns an errno, and a directory handle (optional)
582 Called when opening a directory for reading. If special handling is
583 required to open a directory, this operation can be implemented to handle
588 Arguments: Pathname of a directory, numeric offset, (optional) directory handle
590 Returns a list of 0 or more entries, followed by a numeric errno (usually 0).
591 The entries can be simple strings (filenames), or arrays containing an
592 offset number, the filename, and optionally an array ref containing the
593 stat values (as would be returned from getattr()).
595 This is used to read entries from a directory. It can be used to return just
596 entry names like getdir(), or can get a segment of the available entries,
597 which requires using array refs and the 2- or 3-item form, with offset values
598 starting from 1. If you wish to return the parameters to fill each entry's
599 struct stat, but do not wish to do partial entry lists/entry counting, set
600 the first element of each array to 0 always.
602 Note that if this call is implemented, it overrides getdir() ALWAYS.
606 Arguments: Pathname of a directory, (optional) directory handle
608 Returns an errno or 0 on success
610 Called when there are no more references to an opened directory. Called once
611 for each pathname or handle passed to opendir(). Similar to release(), but
612 for directories. Accepts a return value, but like release(), the response
613 code will not propagate to any corresponding closedir() calls.
617 Arguments: Pathname of a directory, numeric flags, (optional) directory handle
619 Returns an errno or 0 on success.
621 Called to synchronize any changes to a directory's contents. If flag is
622 non-zero, only synchronize user data, otherwise synchronize user data and
629 Returns (optionally) an SV to be passed as private_data via fuse_get_context().
633 Arguments: (optional) private data SV returned from init(), if any.
639 Arguments: Pathname, access mode flags
641 Returns an errno or 0 on success.
643 Determine if the user attempting to access the indicated file has access to
644 perform the requested actions. The user ID can be determined by calling
645 fuse_get_context(). See access(2) for more information.
649 Arguments: Pathname, create mask, open mode flags
651 Returns errno or 0 on success, and (optional) file handle.
653 Create a file with the path indicated, then open a handle for reading and/or
654 writing with the supplied mode flags. Can also return a file handle like
655 open() as part of the call.
659 Arguments: Pathname, numeric offset, (optional) file handle
661 Returns errno or 0 on success
663 Like truncate(), but on an opened file.
667 Arguments: Pathname, (optional) file handle
669 Returns a list, very similar to the 'stat' function (see
670 perlfunc). On error, simply return a single numeric scalar
671 value (e.g. "return -ENOENT();").
673 Like getattr(), but on an opened file.
677 Arguments: Pathname, numeric command code, hashref containing lock parameters, (optional) file handle
679 Returns errno or 0 on success
681 Used to lock or unlock regions of a file. Locking is handled locally, but this
682 allows (especially for networked file systems) for protocol-level locking
683 semantics to also be employed, if any are available.
685 See the Fuse documentation for more explanation of lock(). The needed symbols
686 for the lock constants can be obtained by importing Fcntl.
690 Arguments: Pathname, last accessed time, last modified time
692 Returns errno or 0 on success
694 Like utime(), but allows time resolution down to the nanosecond. Currently
695 times are passed as "numeric" (internally I believe these are represented
696 typically as "long double"), so the sub-second portion is represented as
697 fractions of a second.
699 Note that if this call is implemented, it overrides utime() ALWAYS.
703 Arguments: Pathname, numeric blocksize, numeric block number
705 Returns errno or 0 on success, and physical block number if successful
707 Used to map a block number offset in a file to the physical block offset
708 on the block device backing the file system. This is intended for
709 filesystems that are stored on an actual block device, with the 'blkdev'
714 Arguments: Pathname, (signed) ioctl command code, flags, data if ioctl op is a write, (optional) file handle
716 Returns errno or 0 on success, and data if ioctl op is a read
718 Used to handle ioctl() operations on files. See ioctl(2) for more
719 information on the fine details of ioctl operation numbers. May need to
720 h2ph system headers to get the necessary macros; keep in mind the macros
721 are highly OS-dependent.
723 Keep in mind that read and write are from the client perspective, so
724 read from our end means data is going *out*, and write means data is
725 coming *in*. It can be slightly confusing.
729 Arguments: Pathname, poll handle ID (or undef if none), event mask, (optional) file handle
731 Returns errno or 0 on success, and updated event mask on success
733 Used to handle poll() operations on files. See poll(2) to learn more about
734 event polling. Use IO::Poll to get the POLLIN, POLLOUT, and other symbols
735 to describe the events which can happen on the filehandle. Save the poll
736 handle ID to be passed to C<notify_poll> and C<pollhandle_destroy>
737 functions, if it is not undef. Threading will likely be necessary for this
740 There is not an "out of band" data transfer channel provided as part of
741 FUSE, so POLLPRI/POLLRDBAND/POLLWRBAND won't work.
743 Poll handle is currently a read-only scalar; we are investigating a way
744 to make this an object instead.
748 Mark Glines, E<lt>mark@glines.orgE<gt>
752 L<perl>, the FUSE documentation.