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) ],
24 'xattr' => [ qw(XATTR_CREATE XATTR_REPLACE) ]
27 our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
30 our $VERSION = '0.13';
33 # This AUTOLOAD is used to 'autoload' constants from the constant()
34 # XS function. If a constant is not found then control is passed
35 # to the AUTOLOAD in AutoLoader.
39 ($constname = $AUTOLOAD) =~ s/.*:://;
40 croak "& not defined" if $constname eq 'constant';
41 my $val = constant($constname, @_ ? $_[0] : 0);
44 $AutoLoader::AUTOLOAD = $AUTOLOAD;
45 goto &AutoLoader::AUTOLOAD;
48 croak "Your vendor has not defined Fuse macro $constname";
53 # Fixed between 5.005_53 and 5.005_61
55 *$AUTOLOAD = sub () { $val };
58 *$AUTOLOAD = sub { $val };
64 bootstrap Fuse $VERSION;
67 my @names = qw(getattr readlink getdir mknod mkdir unlink rmdir symlink
68 rename link chmod chown truncate utime open read write statfs
69 flush release fsync setxattr getxattr listxattr removexattr);
70 my $fuse_version = fuse_version();
71 if ($fuse_version >= 2.3) {
72 push(@names, qw/opendir readdir releasedir fsyncdir init destroy/);
74 if ($fuse_version >= 2.5) {
75 push(@names, qw/access create ftruncate fgetattr/);
77 if ($fuse_version >= 2.6) {
78 push(@names, qw/lock utimens bmap/);
80 # if ($fuse_version >= 2.8) {
81 # # junk doesn't contain a function pointer, and hopefully
82 # # never will; it's a "dead" zone in the struct
83 # # fuse_operations where a flag bit is declared. we don't
84 # # need to concern ourselves with it, and it appears any
85 # # arch with a 64 bit pointer will align everything to
86 # # 8 bytes, making the question of pointer alignment for
87 # # the last 2 wrapper functions no big thing.
88 # push(@names, qw/junk ioctl poll/);
90 my @subs = map {undef} @names;
92 my %mapping = map { $_ => $tmp++ } @names;
93 my @otherargs = qw(debug threaded mountpoint mountopts nullpath_ok);
101 while(my $name = shift) {
102 my ($subref) = shift;
103 if(exists($otherargs{$name})) {
104 $otherargs{$name} = $subref;
106 croak "There is no function $name" unless exists($mapping{$name});
107 croak "Usage: Fuse::main(getattr => \"main::my_getattr\", ...)" unless $subref;
108 $subs[$mapping{$name}] = $subref;
111 if($otherargs{threaded}) {
112 # make sure threads are both available, and loaded.
113 if($Config{useithreads}) {
114 if(exists($threads::{VERSION})) {
115 if(exists($threads::shared::{VERSION})) {
118 carp("Thread support requires you to use threads::shared.\nThreads are disabled.\n");
119 $otherargs{threaded} = 0;
122 carp("Thread support requires you to use threads and threads::shared.\nThreads are disabled.\n");
123 $otherargs{threaded} = 0;
126 carp("Thread support was not compiled into this build of perl.\nThreads are disabled.\n");
127 $otherargs{threaded} = 0;
130 perl_fuse_main(@otherargs{@otherargs},@subs);
133 # Autoload methods go after =cut, and are processed by the autosplit program.
140 Fuse - write filesystems in Perl using FUSE
145 my ($mountpoint) = "";
146 $mountpoint = shift(@ARGV) if @ARGV;
147 Fuse::main(mountpoint=>$mountpoint, getattr=>"main::my_getattr", getdir=>"main::my_getdir", ...);
151 This lets you implement filesystems in perl, through the FUSE
152 (Filesystem in USErspace) kernel/lib interface.
154 FUSE expects you to implement callbacks for the various functions.
156 In the following definitions, "errno" can be 0 (for a success),
157 -EINVAL, -ENOENT, -EONFIRE, any integer less than 1 really.
159 You can import standard error constants by saying something like
160 "use POSIX qw(EDOTDOT ENOANO);".
162 Every constant you need (file types, open() flags, error values,
163 etc) can be imported either from POSIX or from Fcntl, often both.
164 See their respective documentations, for more information.
166 =head2 EXPORTED SYMBOLS
170 You can request all exportable symbols by using the tag ":all".
172 You can request the extended attribute symbols by using the tag ":xattr".
173 This will export XATTR_CREATE and XATTR_REPLACE.
179 Takes arguments in the form of hash key=>value pairs. There are
180 many valid keys. Most of them correspond with names of callback
181 functions, as described in section 'FUNCTIONS YOUR FILESYSTEM MAY IMPLEMENT'.
182 A few special keys also exist:
189 This turns FUSE call tracing on and off. Default is 0 (which means off).
197 The point at which to mount this filesystem. There is no default, you must
198 specify this. An example would be '/mnt'.
206 This is a comma seperated list of mount options to pass to the FUSE kernel
209 At present, it allows the specification of the allow_other
210 argument when mounting the new FUSE filesystem. To use this, you will also
211 need 'user_allow_other' in /etc/fuse.conf as per the FUSE documention
213 mountopts => "allow_other" or
222 This turns FUSE multithreading on and off. The default is 0, meaning your FUSE
223 script will run in single-threaded mode. Note that single-threaded mode also
224 means that you will not have to worry about reentrancy, though you will have to
225 worry about recursive lookups. In single-threaded mode, FUSE holds a global
226 lock on your filesystem, and will wait for one callback to return before
227 calling another. This can lead to deadlocks, if your script makes any attempt
228 to access files or directories in the filesystem it is providing. (This
229 includes calling stat() on the mount-point, statfs() calls from the 'df'
230 command, and so on and so forth.) It is worth paying a little attention and
231 being careful about this.
233 Enabling multithreading will cause FUSE to make multiple simultaneous calls
234 into the various callback functions of your perl script. If you enable
235 threaded mode, you can enjoy all the parallel execution and interactive
236 response benefits of threads, and you get to enjoy all the benefits of race
237 conditions and locking bugs, too. Please also ensure any other perl modules
238 you're using are also thread-safe.
240 (If enabled, this option will cause a warning if your perl interpreter was not
241 built with USE_ITHREADS, or if you have failed to use threads or
246 nullpath_ok => boolean
250 This flag tells Fuse to not pass paths for functions that operate on file
251 or directory handles. This will yield empty path parameters for functions
252 including read, write, flush, release, fsync, readdir, releasedir,
253 fsyncdir, truncate, fgetattr and lock. If you use this, you must return
254 file/directory handles from open, opendir and create. Default is 0 (off).
255 Only effective on Fuse 2.8 and up; with earlier versions, this does nothing.
259 =head3 Fuse::fuse_get_context
261 use Fuse "fuse_get_context";
262 my $caller_uid = fuse_get_context()->{"uid"};
263 my $caller_gid = fuse_get_context()->{"gid"};
264 my $caller_pid = fuse_get_context()->{"pid"};
266 Access context information about the current Fuse operation.
268 =head3 Fuse::fuse_version
270 Indicates the Fuse version in use; more accurately, indicates the version
271 of the Fuse API in use at build time. Returned as a decimal value; i.e.,
272 for Fuse API v2.6, will return "2.6".
274 =head2 FUNCTIONS YOUR FILESYSTEM MAY IMPLEMENT
279 Returns a list, very similar to the 'stat' function (see
280 perlfunc). On error, simply return a single numeric scalar
281 value (e.g. "return -ENOENT();").
283 FIXME: the "ino" field is currently ignored. I tried setting it to 0
284 in an example script, which consistently caused segfaults.
286 Fields (the following was stolen from perlfunc(1) with apologies):
288 ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
289 $atime,$mtime,$ctime,$blksize,$blocks)
290 = getattr($filename);
292 Here are the meaning of the fields:
294 0 dev device number of filesystem
296 2 mode file mode (type and permissions)
297 3 nlink number of (hard) links to the file
298 4 uid numeric user ID of file's owner
299 5 gid numeric group ID of file's owner
300 6 rdev the device identifier (special files only)
301 7 size total size of file, in bytes
302 8 atime last access time in seconds since the epoch
303 9 mtime last modify time in seconds since the epoch
304 10 ctime inode change time (NOT creation time!) in seconds
306 11 blksize preferred block size for file system I/O
307 12 blocks actual number of blocks allocated
309 (The epoch was at 00:00 January 1, 1970 GMT.)
313 Arguments: link pathname.
314 Returns a scalar: either a numeric constant, or a text string.
316 This is called when dereferencing symbolic links, to learn the target.
318 example rv: return "/proc/self/fd/stdin";
322 Arguments: Containing directory name.
323 Returns a list: 0 or more text strings (the filenames), followed by a numeric errno (usually 0).
325 This is used to obtain directory listings. It's opendir(), readdir(), filldir() and closedir() all in one call.
327 example rv: return ('.', 'a', 'b', 0);
331 Arguments: Filename, numeric modes, numeric device
332 Returns an errno (0 upon success, as usual).
334 This function is called for all non-directory, non-symlink nodes,
339 Arguments: New directory pathname, numeric modes.
342 Called to create a directory.
349 Called to remove a file, device, or symlink.
356 Called to remove a directory.
360 Arguments: Existing filename, symlink name.
363 Called to create a symbolic link.
367 Arguments: old filename, new filename.
370 Called to rename a file, and/or move a file from one directory to another.
374 Arguments: Existing filename, hardlink name.
377 Called to create hard links.
381 Arguments: Pathname, numeric modes.
384 Called to change permissions on a file/directory/device/symlink.
388 Arguments: Pathname, numeric uid, numeric gid.
391 Called to change ownership of a file/directory/device/symlink.
395 Arguments: Pathname, numeric offset.
398 Called to truncate a file, at the given offset.
402 Arguments: Pathname, numeric actime, numeric modtime.
405 Called to change access/modification times for a file/directory/device/symlink.
409 Arguments: Pathname, numeric flags (which is an OR-ing of stuff like O_RDONLY
410 and O_SYNC, constants you can import from POSIX), fileinfo hash reference.
411 Returns an errno, a file handle (optional).
413 No creation, or trunctation flags (O_CREAT, O_EXCL, O_TRUNC) will be passed to open().
414 The fileinfo hash reference contains flags from the Fuse open call which may be modified by the module. The only fields presently supported are:
415 direct_io (version 2.4 onwards)
416 keep_cache (version 2.4 onwards)
417 nonseekable (version 2.9 onwards)
418 Your open() method needs only check if the operation is permitted for the given flags, and return 0 for success.
419 Optionally a file handle may be returned, which will be passed to subsequent read, write, flush, fsync and release calls.
423 Arguments: Pathname, numeric requested size, numeric offset, file handle
424 Returns a numeric errno, or a string scalar with up to $requestedsize bytes of data.
426 Called in an attempt to fetch a portion of the file.
430 Arguments: Pathname, scalar buffer, numeric offset, file handle. You can use length($buffer) to
432 Returns length($buffer) if successful (number of bytes written).
434 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.
439 Returns any of the following:
445 $namelen, $files, $files_free, $blocks, $blocks_avail, $blocksize
449 -ENOANO(), $namelen, $files, $files_free, $blocks, $blocks_avail, $blocksize
453 Arguments: Pathname, file handle
454 Returns an errno or 0 on success.
456 Called to synchronise any cached data. This is called before the file
457 is closed. It may be called multiple times before a file is closed.
461 Arguments: Pathname, numeric flags passed to open, file handle
462 Returns an errno or 0 on success.
464 Called to indicate that there are no more references to the file. Called once
465 for every file with the same pathname and flags as were passed to open.
469 Arguments: Pathname, numeric flags
470 Returns an errno or 0 on success.
472 Called to synchronise the file's contents. If flags is non-zero,
473 only synchronise the user data. Otherwise synchronise the user and meta data.
477 Arguments: Pathname, extended attribute's name, extended attribute's value, numeric flags (which is an OR-ing of XATTR_CREATE and XATTR_REPLACE
478 Returns an errno or 0 on success.
480 Called to set the value of the named extended attribute.
482 If you wish to reject setting of a particular form of extended attribute name
483 (e.g.: regexps matching user\..* or security\..*), then return - EOPNOTSUPP.
485 If flags is set to XATTR_CREATE and the extended attribute already exists,
486 this should fail with - EEXIST. If flags is set to XATTR_REPLACE
487 and the extended attribute doesn't exist, this should fail with - ENOATTR.
489 XATTR_CREATE and XATTR_REPLACE are provided by this module, but not exported
490 by default. To import them:
500 Arguments: Pathname, extended attribute's name
501 Returns an errno, 0 if there was no value, or the extended attribute's value.
503 Called to get the value of the named extended attribute.
508 Returns a list: 0 or more text strings (the extended attribute names), followed by a numeric errno (usually 0).
512 Arguments: Pathname, extended attribute's name
513 Returns an errno or 0 on success.
517 Arguments: Pathname of a directory
518 Returns an errno, and a directory handle (optional)
520 Called when opening a directory for reading. If special handling is
521 required to open a directory, this operation can be implemented to handle
526 Arguments: Pathname of a directory, numeric offset, (optional) directory handle
527 Returns a list of 0 or more entries, followed by a numeric errno (usually 0).
528 The entries can be simple strings (filenames), or arrays containing an
529 offset number, the filename, and optionally an array ref containing the
530 stat values (as would be returned from getattr()).
532 This is used to read entries from a directory. It can be used to return just
533 entry names like getdir(), or can get a segment of the available entries,
534 which requires using array refs and the 2- or 3-item form, with offset values
535 starting from 1. If you wish to return the parameters to fill each entry's
536 struct stat, but do not wish to do partial entry lists/entry counting, set
537 the first element of each array to 0 always.
539 Note that if this call is implemented, it overrides getdir() ALWAYS.
543 Arguments: Pathname of a directory, (optional) directory handle
544 Returns an errno or 0 on success
546 Called when there are no more references to an opened directory. Called once
547 for each pathname or handle passed to opendir(). Similar to release(), but
548 for directories. Accepts a return value, but like release(), the response
549 code will not propagate to any corresponding closedir() calls.
553 Arguments: Pathname of a directory, numeric flags, (optional) directory handle
554 Returns an errno or 0 on success.
556 Called to synchronize any changes to a directory's contents. If flag is
557 non-zero, only synchronize user data, otherwise synchronize user data and
563 Returns (optionally) an SV to be passed as private_data via fuse_get_context().
567 Arguments: (optional) private data SV returned from init(), if any.
572 Arguments: Pathname, access mode flags
573 Returns an errno or 0 on success.
575 Determine if the user attempting to access the indicated file has access to
576 perform the requested actions. The user ID can be determined by calling
577 fuse_get_context(). See access(2) for more information.
581 Arguments: Pathname, create mask, open mode flags
582 Returns errno or 0 on success, and (optional) file handle.
584 Create a file with the path indicated, then open a handle for reading and/or
585 writing with the supplied mode flags. Can also return a file handle like
586 open() as part of the call.
590 Arguments: Pathname, numeric offset, (optional) file handle
591 Returns errno or 0 on success
593 Like truncate(), but on an opened file.
597 Arguments: Pathname, (optional) file handle
598 Returns a list, very similar to the 'stat' function (see
599 perlfunc). On error, simply return a single numeric scalar
600 value (e.g. "return -ENOENT();").
602 Like getattr(), but on an opened file.
606 Arguments: Pathname, numeric command code, hashref containing lock parameters, (optional) file handle
607 Returns errno or 0 on success
609 Used to lock or unlock regions of a file. Locking is handled locally, but this
610 allows (especially for networked file systems) for protocol-level locking
611 semantics to also be employed, if any are available.
613 See the Fuse documentation for more explanation of lock(). The needed symbols
614 for the lock constants can be obtained by importing Fcntl.
618 Arguments: Pathname, last accessed time, last modified time
619 Returns errno or 0 on success
621 Like utime(), but allows time resolution down to the nanosecond. Currently
622 times are passed as "numeric" (internally I believe these are represented
623 typically as "long double"), so the sub-second portion is represented as
624 fractions of a second.
626 Note that if this call is implemented, it overrides utime() ALWAYS.
630 Arguments: Pathname, numeric blocksize, numeric block number
631 Returns errno or 0 on success, and physical block number if successful
633 Used to map a block number offset in a file to the physical block offset
634 on the block device backing the file system. This is intended for
635 filesystems that are stored on an actual block device, with the 'blkdev'
640 Mark Glines, E<lt>mark@glines.orgE<gt>
644 L<perl>, the FUSE documentation.