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 $VERSION = '0.14';
33 # This AUTOLOAD is used to 'autoload' constants from the constant()
34 # XS function. If a constant is not found then control is passed
35 # to the AUTOLOAD in AutoLoader.
39 ($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/);
89 # push(@names, qw/junk ioctl poll/);
91 my @subs = map {undef} @names;
93 my %mapping = map { $_ => $tmp++ } @names;
94 my @otherargs = qw(debug threaded mountpoint mountopts nullpath_ok);
102 while(my $name = shift) {
103 my ($subref) = shift;
104 if(exists($otherargs{$name})) {
105 $otherargs{$name} = $subref;
107 croak "There is no function $name" unless exists($mapping{$name});
108 croak "Usage: Fuse::main(getattr => \"main::my_getattr\", ...)" unless $subref;
109 $subs[$mapping{$name}] = $subref;
112 if($otherargs{threaded}) {
113 # make sure threads are both available, and loaded.
114 if($Config{useithreads}) {
115 if(exists($threads::{VERSION})) {
116 if(exists($threads::shared::{VERSION})) {
119 carp("Thread support requires you to use threads::shared.\nThreads are disabled.\n");
120 $otherargs{threaded} = 0;
123 carp("Thread support requires you to use threads and threads::shared.\nThreads are disabled.\n");
124 $otherargs{threaded} = 0;
127 carp("Thread support was not compiled into this build of perl.\nThreads are disabled.\n");
128 $otherargs{threaded} = 0;
131 perl_fuse_main(@otherargs{@otherargs},@subs);
134 # Autoload methods go after =cut, and are processed by the autosplit program.
141 Fuse - write filesystems in Perl using FUSE
146 my ($mountpoint) = "";
147 $mountpoint = shift(@ARGV) if @ARGV;
148 Fuse::main(mountpoint=>$mountpoint, getattr=>"main::my_getattr", getdir=>"main::my_getdir", ...);
152 This lets you implement filesystems in perl, through the FUSE
153 (Filesystem in USErspace) kernel/lib interface.
155 FUSE expects you to implement callbacks for the various functions.
157 In the following definitions, "errno" can be 0 (for a success),
158 -EINVAL, -ENOENT, -EONFIRE, any integer less than 1 really.
160 You can import standard error constants by saying something like
161 "use POSIX qw(EDOTDOT ENOANO);".
163 Every constant you need (file types, open() flags, error values,
164 etc) can be imported either from POSIX or from Fcntl, often both.
165 See their respective documentations, for more information.
167 =head2 EXPORTED SYMBOLS
171 You can request all exportable symbols by using the tag ":all".
173 You can request the extended attribute symbols by using the tag ":xattr".
174 This will export XATTR_CREATE and XATTR_REPLACE.
180 Takes arguments in the form of hash key=>value pairs. There are
181 many valid keys. Most of them correspond with names of callback
182 functions, as described in section 'FUNCTIONS YOUR FILESYSTEM MAY IMPLEMENT'.
183 A few special keys also exist:
190 This turns FUSE call tracing on and off. Default is 0 (which means off).
198 The point at which to mount this filesystem. There is no default, you must
199 specify this. An example would be '/mnt'.
207 This is a comma seperated list of mount options to pass to the FUSE kernel
210 At present, it allows the specification of the allow_other
211 argument when mounting the new FUSE filesystem. To use this, you will also
212 need 'user_allow_other' in /etc/fuse.conf as per the FUSE documention
214 mountopts => "allow_other" or
223 This turns FUSE multithreading on and off. The default is 0, meaning your FUSE
224 script will run in single-threaded mode. Note that single-threaded mode also
225 means that you will not have to worry about reentrancy, though you will have to
226 worry about recursive lookups. In single-threaded mode, FUSE holds a global
227 lock on your filesystem, and will wait for one callback to return before
228 calling another. This can lead to deadlocks, if your script makes any attempt
229 to access files or directories in the filesystem it is providing. (This
230 includes calling stat() on the mount-point, statfs() calls from the 'df'
231 command, and so on and so forth.) It is worth paying a little attention and
232 being careful about this.
234 Enabling multithreading will cause FUSE to make multiple simultaneous calls
235 into the various callback functions of your perl script. If you enable
236 threaded mode, you can enjoy all the parallel execution and interactive
237 response benefits of threads, and you get to enjoy all the benefits of race
238 conditions and locking bugs, too. Please also ensure any other perl modules
239 you're using are also thread-safe.
241 (If enabled, this option will cause a warning if your perl interpreter was not
242 built with USE_ITHREADS, or if you have failed to use threads or
247 nullpath_ok => boolean
251 This flag tells Fuse to not pass paths for functions that operate on file
252 or directory handles. This will yield empty path parameters for functions
253 including read, write, flush, release, fsync, readdir, releasedir,
254 fsyncdir, truncate, fgetattr and lock. If you use this, you must return
255 file/directory handles from open, opendir and create. Default is 0 (off).
256 Only effective on Fuse 2.8 and up; with earlier versions, this does nothing.
260 =head3 Fuse::fuse_get_context
262 use Fuse "fuse_get_context";
263 my $caller_uid = fuse_get_context()->{"uid"};
264 my $caller_gid = fuse_get_context()->{"gid"};
265 my $caller_pid = fuse_get_context()->{"pid"};
267 Access context information about the current Fuse operation.
269 =head3 Fuse::fuse_version
271 Indicates the Fuse version in use; more accurately, indicates the version
272 of the Fuse API in use at build time. Returned as a decimal value; i.e.,
273 for Fuse API v2.6, will return "2.6".
275 =head2 FUNCTIONS YOUR FILESYSTEM MAY IMPLEMENT
281 Returns a list, very similar to the 'stat' function (see
282 perlfunc). On error, simply return a single numeric scalar
283 value (e.g. "return -ENOENT();").
285 FIXME: the "ino" field is currently ignored. I tried setting it to 0
286 in an example script, which consistently caused segfaults.
288 Fields (the following was stolen from perlfunc(1) with apologies):
290 ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
291 $atime,$mtime,$ctime,$blksize,$blocks)
292 = getattr($filename);
294 Here are the meaning of the fields:
296 0 dev device number of filesystem
298 2 mode file mode (type and permissions)
299 3 nlink number of (hard) links to the file
300 4 uid numeric user ID of file's owner
301 5 gid numeric group ID of file's owner
302 6 rdev the device identifier (special files only)
303 7 size total size of file, in bytes
304 8 atime last access time in seconds since the epoch
305 9 mtime last modify time in seconds since the epoch
306 10 ctime inode change time (NOT creation time!) in seconds
308 11 blksize preferred block size for file system I/O
309 12 blocks actual number of blocks allocated
311 (The epoch was at 00:00 January 1, 1970 GMT.)
315 Arguments: link pathname.
317 Returns a scalar: either a numeric constant, or a text string.
319 This is called when dereferencing symbolic links, to learn the target.
321 example rv: return "/proc/self/fd/stdin";
325 Arguments: Containing directory name.
327 Returns a list: 0 or more text strings (the filenames), followed by a numeric errno (usually 0).
329 This is used to obtain directory listings. It's opendir(), readdir(), filldir() and closedir() all in one call.
331 example rv: return ('.', 'a', 'b', 0);
335 Arguments: Filename, numeric modes, numeric device
337 Returns an errno (0 upon success, as usual).
339 This function is called for all non-directory, non-symlink nodes,
344 Arguments: New directory pathname, numeric modes.
348 Called to create a directory.
356 Called to remove a file, device, or symlink.
364 Called to remove a directory.
368 Arguments: Existing filename, symlink name.
372 Called to create a symbolic link.
376 Arguments: old filename, new filename.
380 Called to rename a file, and/or move a file from one directory to another.
384 Arguments: Existing filename, hardlink name.
388 Called to create hard links.
392 Arguments: Pathname, numeric modes.
396 Called to change permissions on a file/directory/device/symlink.
400 Arguments: Pathname, numeric uid, numeric gid.
404 Called to change ownership of a file/directory/device/symlink.
408 Arguments: Pathname, numeric offset.
412 Called to truncate a file, at the given offset.
416 Arguments: Pathname, numeric actime, numeric modtime.
420 Called to change access/modification times for a file/directory/device/symlink.
424 Arguments: Pathname, numeric flags (which is an OR-ing of stuff like O_RDONLY
425 and O_SYNC, constants you can import from POSIX), fileinfo hash reference.
427 Returns an errno, a file handle (optional).
429 No creation, or trunctation flags (O_CREAT, O_EXCL, O_TRUNC) will be passed to open().
430 The fileinfo hash reference contains flags from the Fuse open call which may be modified by the module. The only fields presently supported are:
431 direct_io (version 2.4 onwards)
432 keep_cache (version 2.4 onwards)
433 nonseekable (version 2.9 onwards)
434 Your open() method needs only check if the operation is permitted for the given flags, and return 0 for success.
435 Optionally a file handle may be returned, which will be passed to subsequent read, write, flush, fsync and release calls.
439 Arguments: Pathname, numeric requested size, numeric offset, file handle
441 Returns a numeric errno, or a string scalar with up to $requestedsize bytes of data.
443 Called in an attempt to fetch a portion of the file.
447 Arguments: Pathname, scalar buffer, numeric offset, file handle. You can use length($buffer) to
449 Returns length($buffer) if successful (number of bytes written).
451 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.
457 Returns any of the following:
463 $namelen, $files, $files_free, $blocks, $blocks_avail, $blocksize
467 -ENOANO(), $namelen, $files, $files_free, $blocks, $blocks_avail, $blocksize
471 Arguments: Pathname, file handle
473 Returns an errno or 0 on success.
475 Called to synchronise any cached data. This is called before the file
476 is closed. It may be called multiple times before a file is closed.
480 Arguments: Pathname, numeric flags passed to open, file handle
481 Returns an errno or 0 on success.
483 Called to indicate that there are no more references to the file. Called once
484 for every file with the same pathname and flags as were passed to open.
488 Arguments: Pathname, numeric flags
490 Returns an errno or 0 on success.
492 Called to synchronise the file's contents. If flags is non-zero,
493 only synchronise the user data. Otherwise synchronise the user and meta data.
497 Arguments: Pathname, extended attribute's name, extended attribute's value, numeric flags (which is an OR-ing of XATTR_CREATE and XATTR_REPLACE
499 Returns an errno or 0 on success.
501 Called to set the value of the named extended attribute.
503 If you wish to reject setting of a particular form of extended attribute name
504 (e.g.: regexps matching user\..* or security\..*), then return - EOPNOTSUPP.
506 If flags is set to XATTR_CREATE and the extended attribute already exists,
507 this should fail with - EEXIST. If flags is set to XATTR_REPLACE
508 and the extended attribute doesn't exist, this should fail with - ENOATTR.
510 XATTR_CREATE and XATTR_REPLACE are provided by this module, but not exported
511 by default. To import them:
521 Arguments: Pathname, extended attribute's name
523 Returns an errno, 0 if there was no value, or the extended attribute's value.
525 Called to get the value of the named extended attribute.
531 Returns a list: 0 or more text strings (the extended attribute names), followed by a numeric errno (usually 0).
535 Arguments: Pathname, extended attribute's name
537 Returns an errno or 0 on success.
541 Arguments: Pathname of a directory
542 Returns an errno, and a directory handle (optional)
544 Called when opening a directory for reading. If special handling is
545 required to open a directory, this operation can be implemented to handle
550 Arguments: Pathname of a directory, numeric offset, (optional) directory handle
552 Returns a list of 0 or more entries, followed by a numeric errno (usually 0).
553 The entries can be simple strings (filenames), or arrays containing an
554 offset number, the filename, and optionally an array ref containing the
555 stat values (as would be returned from getattr()).
557 This is used to read entries from a directory. It can be used to return just
558 entry names like getdir(), or can get a segment of the available entries,
559 which requires using array refs and the 2- or 3-item form, with offset values
560 starting from 1. If you wish to return the parameters to fill each entry's
561 struct stat, but do not wish to do partial entry lists/entry counting, set
562 the first element of each array to 0 always.
564 Note that if this call is implemented, it overrides getdir() ALWAYS.
568 Arguments: Pathname of a directory, (optional) directory handle
570 Returns an errno or 0 on success
572 Called when there are no more references to an opened directory. Called once
573 for each pathname or handle passed to opendir(). Similar to release(), but
574 for directories. Accepts a return value, but like release(), the response
575 code will not propagate to any corresponding closedir() calls.
579 Arguments: Pathname of a directory, numeric flags, (optional) directory handle
581 Returns an errno or 0 on success.
583 Called to synchronize any changes to a directory's contents. If flag is
584 non-zero, only synchronize user data, otherwise synchronize user data and
591 Returns (optionally) an SV to be passed as private_data via fuse_get_context().
595 Arguments: (optional) private data SV returned from init(), if any.
601 Arguments: Pathname, access mode flags
603 Returns an errno or 0 on success.
605 Determine if the user attempting to access the indicated file has access to
606 perform the requested actions. The user ID can be determined by calling
607 fuse_get_context(). See access(2) for more information.
611 Arguments: Pathname, create mask, open mode flags
613 Returns errno or 0 on success, and (optional) file handle.
615 Create a file with the path indicated, then open a handle for reading and/or
616 writing with the supplied mode flags. Can also return a file handle like
617 open() as part of the call.
621 Arguments: Pathname, numeric offset, (optional) file handle
623 Returns errno or 0 on success
625 Like truncate(), but on an opened file.
629 Arguments: Pathname, (optional) file handle
631 Returns a list, very similar to the 'stat' function (see
632 perlfunc). On error, simply return a single numeric scalar
633 value (e.g. "return -ENOENT();").
635 Like getattr(), but on an opened file.
639 Arguments: Pathname, numeric command code, hashref containing lock parameters, (optional) file handle
641 Returns errno or 0 on success
643 Used to lock or unlock regions of a file. Locking is handled locally, but this
644 allows (especially for networked file systems) for protocol-level locking
645 semantics to also be employed, if any are available.
647 See the Fuse documentation for more explanation of lock(). The needed symbols
648 for the lock constants can be obtained by importing Fcntl.
652 Arguments: Pathname, last accessed time, last modified time
654 Returns errno or 0 on success
656 Like utime(), but allows time resolution down to the nanosecond. Currently
657 times are passed as "numeric" (internally I believe these are represented
658 typically as "long double"), so the sub-second portion is represented as
659 fractions of a second.
661 Note that if this call is implemented, it overrides utime() ALWAYS.
665 Arguments: Pathname, numeric blocksize, numeric block number
667 Returns errno or 0 on success, and physical block number if successful
669 Used to map a block number offset in a file to the physical block offset
670 on the block device backing the file system. This is intended for
671 filesystems that are stored on an actual block device, with the 'blkdev'
676 Arguments: Pathname, (signed) ioctl command code, flags, data if ioctl op is a write, (optional) file handle
678 Returns errno or 0 on success, and data if ioctl op is a read
680 Used to handle ioctl() operations on files. See ioctl(2) for more
681 information on the fine details of ioctl operation numbers. May need to
682 h2ph system headers to get the necessary macros; keep in mind the macros
683 are highly OS-dependent.
685 Keep in mind that read and write are from the client perspective, so
686 read from our end means data is going *out*, and write means data is
687 coming *in*. It can be slightly confusing.
691 Mark Glines, E<lt>mark@glines.orgE<gt>
695 L<perl>, the FUSE documentation.