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Revision 1.208 by root, Mon Sep 26 20:19:08 2011 UTC vs.
Revision 1.272 by root, Fri Jun 23 22:09:50 2017 UTC

1=head1 NAME 1=head1 NAME
2 2
3IO::AIO - Asynchronous Input/Output 3IO::AIO - Asynchronous/Advanced Input/Output
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
58not well-supported or restricted (GNU/Linux doesn't allow them on normal 58not well-supported or restricted (GNU/Linux doesn't allow them on normal
59files currently, for example), and they would only support aio_read and 59files currently, for example), and they would only support aio_read and
60aio_write, so the remaining functionality would have to be implemented 60aio_write, so the remaining functionality would have to be implemented
61using threads anyway. 61using threads anyway.
62 62
63In addition to asynchronous I/O, this module also exports some rather
64arcane interfaces, such as C<madvise> or linux's C<splice> system call,
65which is why the C<A> in C<AIO> can also mean I<advanced>.
66
63Although the module will work in the presence of other (Perl-) threads, 67Although the module will work in the presence of other (Perl-) threads,
64it is currently not reentrant in any way, so use appropriate locking 68it is currently not reentrant in any way, so use appropriate locking
65yourself, always call C<poll_cb> from within the same thread, or never 69yourself, always call C<poll_cb> from within the same thread, or never
66call C<poll_cb> (or other C<aio_> functions) recursively. 70call C<poll_cb> (or other C<aio_> functions) recursively.
67 71
68=head2 EXAMPLE 72=head2 EXAMPLE
69 73
70This is a simple example that uses the EV module and loads 74This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously: 75F</etc/passwd> asynchronously:
72 76
73 use Fcntl;
74 use EV; 77 use EV;
75 use IO::AIO; 78 use IO::AIO;
76 79
77 # register the IO::AIO callback with EV 80 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 81 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
95 98
96 # file contents now in $contents 99 # file contents now in $contents
97 print $contents; 100 print $contents;
98 101
99 # exit event loop and program 102 # exit event loop and program
100 EV::unloop; 103 EV::break;
101 }; 104 };
102 }; 105 };
103 106
104 # possibly queue up other requests, or open GUI windows, 107 # possibly queue up other requests, or open GUI windows,
105 # check for sockets etc. etc. 108 # check for sockets etc. etc.
106 109
107 # process events as long as there are some: 110 # process events as long as there are some:
108 EV::loop; 111 EV::run;
109 112
110=head1 REQUEST ANATOMY AND LIFETIME 113=head1 REQUEST ANATOMY AND LIFETIME
111 114
112Every C<aio_*> function creates a request. which is a C data structure not 115Every C<aio_*> function creates a request. which is a C data structure not
113directly visible to Perl. 116directly visible to Perl.
168use common::sense; 171use common::sense;
169 172
170use base 'Exporter'; 173use base 'Exporter';
171 174
172BEGIN { 175BEGIN {
173 our $VERSION = '4.0'; 176 our $VERSION = 4.35;
174 177
175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 178 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 179 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 180 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate 181 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179 aio_pathsync aio_readahead 182 aio_pathsync aio_readahead aio_fiemap aio_allocate
180 aio_rename aio_link aio_move aio_copy aio_group 183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 184 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182 aio_chmod aio_utime aio_truncate 185 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 186 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 187 aio_statvfs
185 aio_wd); 188 aio_wd);
202 205
203=head1 FUNCTIONS 206=head1 FUNCTIONS
204 207
205=head2 QUICK OVERVIEW 208=head2 QUICK OVERVIEW
206 209
207This section simply lists the prototypes of the most important functions 210This section simply lists the prototypes most of the functions for
208for quick reference. See the following sections for function-by-function 211quick reference. See the following sections for function-by-function
209documentation. 212documentation.
210 213
211 aio_wd $pathname, $callback->($wd) 214 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh) 215 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status) 216 aio_close $fh, $callback->($status)
217 aio_seek $fh,$offset,$whence, $callback->($offs)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 218 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 219 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 220 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval) 221 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status) 222 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status) 223 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs) 224 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 225 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 226 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
227 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status) 228 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 229 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
230 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225 aio_unlink $pathname, $callback->($status) 231 aio_unlink $pathname, $callback->($status)
226 aio_mknod $path, $mode, $dev, $callback->($status) 232 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status) 233 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status) 234 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $path, $callback->($link) 235 aio_readlink $pathname, $callback->($link)
230 aio_realpath $path, $callback->($link) 236 aio_realpath $pathname, $callback->($path)
231 aio_rename $srcpath, $dstpath, $callback->($status) 237 aio_rename $srcpath, $dstpath, $callback->($status)
238 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status) 239 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status) 240 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries) 241 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 242 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 243 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 244 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
245 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238 aio_load $path, $data, $callback->($status) 246 aio_load $pathname, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status) 247 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status) 248 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $path, $callback->($status) 249 aio_rmtree $pathname, $callback->($status)
250 aio_fcntl $fh, $cmd, $arg, $callback->($status)
251 aio_ioctl $fh, $request, $buf, $callback->($status)
243 aio_sync $callback->($status) 252 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status) 253 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status) 254 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status) 255 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 256 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248 aio_pathsync $path, $callback->($status) 257 aio_pathsync $pathname, $callback->($status)
249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 258 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 260 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252 aio_mlockall $flags, $callback->($status) 261 aio_mlockall $flags, $callback->($status)
253 aio_group $callback->(...) 262 aio_group $callback->(...)
254 aio_nop $callback->() 263 aio_nop $callback->()
271 IO::AIO::nready 280 IO::AIO::nready
272 IO::AIO::npending 281 IO::AIO::npending
273 282
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count 283 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice 284 IO::AIO::fadvise $fh, $offset, $len, $advice
285 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
286 IO::AIO::munmap $scalar
276 IO::AIO::madvise $scalar, $offset, $length, $advice 287 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect 288 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef 289 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall 290 IO::AIO::munlockall
280 291
281=head2 AIO REQUEST FUNCTIONS 292=head2 API NOTES
282 293
283All the C<aio_*> calls are more or less thin wrappers around the syscall 294All the C<aio_*> calls are more or less thin wrappers around the syscall
284with the same name (sans C<aio_>). The arguments are similar or identical, 295with the same name (sans C<aio_>). The arguments are similar or identical,
285and they all accept an additional (and optional) C<$callback> argument 296and they all accept an additional (and optional) C<$callback> argument
286which must be a code reference. This code reference will get called with 297which must be a code reference. This code reference will be called after
287the syscall return code (e.g. most syscalls return C<-1> on error, unlike 298the syscall has been executed in an asynchronous fashion. The results
288perl, which usually delivers "false") as its sole argument after the given 299of the request will be passed as arguments to the callback (and, if an
289syscall has been executed asynchronously. 300error occured, in C<$!>) - for most requests the syscall return code (e.g.
301most syscalls return C<-1> on error, unlike perl, which usually delivers
302"false").
303
304Some requests (such as C<aio_readdir>) pass the actual results and
305communicate failures by passing C<undef>.
290 306
291All functions expecting a filehandle keep a copy of the filehandle 307All functions expecting a filehandle keep a copy of the filehandle
292internally until the request has finished. 308internally until the request has finished.
293 309
294All functions return request objects of type L<IO::AIO::REQ> that allow 310All functions return request objects of type L<IO::AIO::REQ> that allow
295further manipulation of those requests while they are in-flight. 311further manipulation of those requests while they are in-flight.
296 312
297The pathnames you pass to these routines I<must> be absolute and 313The pathnames you pass to these routines I<should> be absolute. The
298encoded as octets. The reason for the former is that at the time the 314reason for this is that at the time the request is being executed, the
299request is being executed, the current working directory could have 315current working directory could have changed. Alternatively, you can
300changed. Alternatively, you can make sure that you never change the 316make sure that you never change the current working directory anywhere
301current working directory anywhere in the program and then use relative 317in the program and then use relative paths. You can also take advantage
302paths. 318of IO::AIOs working directory abstraction, that lets you specify paths
319relative to some previously-opened "working directory object" - see the
320description of the C<IO::AIO::WD> class later in this document.
303 321
304To encode pathnames as octets, either make sure you either: a) always pass 322To encode pathnames as octets, either make sure you either: a) always pass
305in filenames you got from outside (command line, readdir etc.) without 323in filenames you got from outside (command line, readdir etc.) without
306tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 324tinkering, b) are in your native filesystem encoding, c) use the Encode
307your pathnames to the locale (or other) encoding in effect in the user 325module and encode your pathnames to the locale (or other) encoding in
308environment, d) use Glib::filename_from_unicode on unicode filenames or e) 326effect in the user environment, d) use Glib::filename_from_unicode on
309use something else to ensure your scalar has the correct contents. 327unicode filenames or e) use something else to ensure your scalar has the
328correct contents.
310 329
311This works, btw. independent of the internal UTF-8 bit, which IO::AIO 330This works, btw. independent of the internal UTF-8 bit, which IO::AIO
312handles correctly whether it is set or not. 331handles correctly whether it is set or not.
332
333=head2 AIO REQUEST FUNCTIONS
313 334
314=over 4 335=over 4
315 336
316=item $prev_pri = aioreq_pri [$pri] 337=item $prev_pri = aioreq_pri [$pri]
317 338
347 368
348 369
349=item aio_open $pathname, $flags, $mode, $callback->($fh) 370=item aio_open $pathname, $flags, $mode, $callback->($fh)
350 371
351Asynchronously open or create a file and call the callback with a newly 372Asynchronously open or create a file and call the callback with a newly
352created filehandle for the file. 373created filehandle for the file (or C<undef> in case of an error).
353 374
354The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 375The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
355for an explanation. 376for an explanation.
356 377
357The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 378The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
380following POSIX and non-POSIX constants are available (missing ones on 401following POSIX and non-POSIX constants are available (missing ones on
381your system are, as usual, C<0>): 402your system are, as usual, C<0>):
382 403
383C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 404C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
384C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 405C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
385C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 406C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
386 407
387 408
388=item aio_close $fh, $callback->($status) 409=item aio_close $fh, $callback->($status)
389 410
390Asynchronously close a file and call the callback with the result 411Asynchronously close a file and call the callback with the result
400Or in other words: the file descriptor will be closed, but it will not be 421Or in other words: the file descriptor will be closed, but it will not be
401free for reuse until the perl filehandle is closed. 422free for reuse until the perl filehandle is closed.
402 423
403=cut 424=cut
404 425
426=item aio_seek $fh, $offset, $whence, $callback->($offs)
427
428Seeks the filehandle to the new C<$offset>, similarly to perl's
429C<sysseek>. The C<$whence> can use the traditional values (C<0> for
430C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
431C<IO::AIO::SEEK_END>).
432
433The resulting absolute offset will be passed to the callback, or C<-1> in
434case of an error.
435
436In theory, the C<$whence> constants could be different than the
437corresponding values from L<Fcntl>, but perl guarantees they are the same,
438so don't panic.
439
440As a GNU/Linux (and maybe Solaris) extension, also the constants
441C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
442could be found. No guarantees about suitability for use in C<aio_seek> or
443Perl's C<sysseek> can be made though, although I would naively assume they
444"just work".
445
405=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 446=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
406 447
407=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 448=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
408 449
409Reads or writes C<$length> bytes from or to the specified C<$fh> and 450Reads or writes C<$length> bytes from or to the specified C<$fh> and
410C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 451C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
411and calls the callback without the actual number of bytes read (or -1 on 452calls the callback with the actual number of bytes transferred (or -1 on
412error, just like the syscall). 453error, just like the syscall).
413 454
414C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 455C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
415offset plus the actual number of bytes read. 456offset plus the actual number of bytes read.
416 457
474As native sendfile syscalls (as practically any non-POSIX interface hacked 515As native sendfile syscalls (as practically any non-POSIX interface hacked
475together in a hurry to improve benchmark numbers) tend to be rather buggy 516together in a hurry to improve benchmark numbers) tend to be rather buggy
476on many systems, this implementation tries to work around some known bugs 517on many systems, this implementation tries to work around some known bugs
477in Linux and FreeBSD kernels (probably others, too), but that might fail, 518in Linux and FreeBSD kernels (probably others, too), but that might fail,
478so you really really should check the return value of C<aio_sendfile> - 519so you really really should check the return value of C<aio_sendfile> -
479fewre bytes than expected might have been transferred. 520fewer bytes than expected might have been transferred.
480 521
481 522
482=item aio_readahead $fh,$offset,$length, $callback->($retval) 523=item aio_readahead $fh,$offset,$length, $callback->($retval)
483 524
484C<aio_readahead> populates the page cache with data from a file so that 525C<aio_readahead> populates the page cache with data from a file so that
488whole pages, so that offset is effectively rounded down to a page boundary 529whole pages, so that offset is effectively rounded down to a page boundary
489and bytes are read up to the next page boundary greater than or equal to 530and bytes are read up to the next page boundary greater than or equal to
490(off-set+length). C<aio_readahead> does not read beyond the end of the 531(off-set+length). C<aio_readahead> does not read beyond the end of the
491file. The current file offset of the file is left unchanged. 532file. The current file offset of the file is left unchanged.
492 533
493If that syscall doesn't exist (likely if your OS isn't Linux) it will be 534If that syscall doesn't exist (likely if your kernel isn't Linux) it will
494emulated by simply reading the data, which would have a similar effect. 535be emulated by simply reading the data, which would have a similar effect.
495 536
496 537
497=item aio_stat $fh_or_path, $callback->($status) 538=item aio_stat $fh_or_path, $callback->($status)
498 539
499=item aio_lstat $fh, $callback->($status) 540=item aio_lstat $fh, $callback->($status)
568 namemax => 255, 609 namemax => 255,
569 frsize => 1024, 610 frsize => 1024,
570 fsid => 1810 611 fsid => 1810
571 } 612 }
572 613
614Here is a (likely partial - send me updates!) list of fsid values used by
615Linux - it is safe to hardcode these when C<$^O> is C<linux>:
616
617 0x0000adf5 adfs
618 0x0000adff affs
619 0x5346414f afs
620 0x09041934 anon-inode filesystem
621 0x00000187 autofs
622 0x42465331 befs
623 0x1badface bfs
624 0x42494e4d binfmt_misc
625 0x9123683e btrfs
626 0x0027e0eb cgroupfs
627 0xff534d42 cifs
628 0x73757245 coda
629 0x012ff7b7 coh
630 0x28cd3d45 cramfs
631 0x453dcd28 cramfs-wend (wrong endianness)
632 0x64626720 debugfs
633 0x00001373 devfs
634 0x00001cd1 devpts
635 0x0000f15f ecryptfs
636 0x00414a53 efs
637 0x0000137d ext
638 0x0000ef53 ext2/ext3/ext4
639 0x0000ef51 ext2
640 0xf2f52010 f2fs
641 0x00004006 fat
642 0x65735546 fuseblk
643 0x65735543 fusectl
644 0x0bad1dea futexfs
645 0x01161970 gfs2
646 0x47504653 gpfs
647 0x00004244 hfs
648 0xf995e849 hpfs
649 0x00c0ffee hostfs
650 0x958458f6 hugetlbfs
651 0x2bad1dea inotifyfs
652 0x00009660 isofs
653 0x000072b6 jffs2
654 0x3153464a jfs
655 0x6b414653 k-afs
656 0x0bd00bd0 lustre
657 0x0000137f minix
658 0x0000138f minix 30 char names
659 0x00002468 minix v2
660 0x00002478 minix v2 30 char names
661 0x00004d5a minix v3
662 0x19800202 mqueue
663 0x00004d44 msdos
664 0x0000564c novell
665 0x00006969 nfs
666 0x6e667364 nfsd
667 0x00003434 nilfs
668 0x5346544e ntfs
669 0x00009fa1 openprom
670 0x7461636F ocfs2
671 0x00009fa0 proc
672 0x6165676c pstorefs
673 0x0000002f qnx4
674 0x68191122 qnx6
675 0x858458f6 ramfs
676 0x52654973 reiserfs
677 0x00007275 romfs
678 0x67596969 rpc_pipefs
679 0x73636673 securityfs
680 0xf97cff8c selinux
681 0x0000517b smb
682 0x534f434b sockfs
683 0x73717368 squashfs
684 0x62656572 sysfs
685 0x012ff7b6 sysv2
686 0x012ff7b5 sysv4
687 0x01021994 tmpfs
688 0x15013346 udf
689 0x00011954 ufs
690 0x54190100 ufs byteswapped
691 0x00009fa2 usbdevfs
692 0x01021997 v9fs
693 0xa501fcf5 vxfs
694 0xabba1974 xenfs
695 0x012ff7b4 xenix
696 0x58465342 xfs
697 0x012fd16d xia
573 698
574=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 699=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
575 700
576Works like perl's C<utime> function (including the special case of $atime 701Works like perl's C<utime> function (including the special case of $atime
577and $mtime being undef). Fractional times are supported if the underlying 702and $mtime being undef). Fractional times are supported if the underlying
605=item aio_truncate $fh_or_path, $offset, $callback->($status) 730=item aio_truncate $fh_or_path, $offset, $callback->($status)
606 731
607Works like truncate(2) or ftruncate(2). 732Works like truncate(2) or ftruncate(2).
608 733
609 734
735=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
736
737Allocates or frees disk space according to the C<$mode> argument. See the
738linux C<fallocate> documentation for details.
739
740C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
741space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
742to deallocate a file range.
743
744IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
745(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
746your L<fallocate(2)> manpage).
747
748The file system block size used by C<fallocate> is presumably the
749C<f_bsize> returned by C<statvfs>.
750
751If C<fallocate> isn't available or cannot be emulated (currently no
752emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
753
754
610=item aio_chmod $fh_or_path, $mode, $callback->($status) 755=item aio_chmod $fh_or_path, $mode, $callback->($status)
611 756
612Works like perl's C<chmod> function. 757Works like perl's C<chmod> function.
613 758
614 759
616 761
617Asynchronously unlink (delete) a file and call the callback with the 762Asynchronously unlink (delete) a file and call the callback with the
618result code. 763result code.
619 764
620 765
621=item aio_mknod $path, $mode, $dev, $callback->($status) 766=item aio_mknod $pathname, $mode, $dev, $callback->($status)
622 767
623[EXPERIMENTAL] 768[EXPERIMENTAL]
624 769
625Asynchronously create a device node (or fifo). See mknod(2). 770Asynchronously create a device node (or fifo). See mknod(2).
626 771
627The only (POSIX-) portable way of calling this function is: 772The only (POSIX-) portable way of calling this function is:
628 773
629 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 774 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
630 775
631See C<aio_stat> for info about some potentially helpful extra constants 776See C<aio_stat> for info about some potentially helpful extra constants
632and functions. 777and functions.
633 778
634=item aio_link $srcpath, $dstpath, $callback->($status) 779=item aio_link $srcpath, $dstpath, $callback->($status)
641 786
642Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 787Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
643the path C<$dstpath> and call the callback with the result code. 788the path C<$dstpath> and call the callback with the result code.
644 789
645 790
646=item aio_readlink $path, $callback->($link) 791=item aio_readlink $pathname, $callback->($link)
647 792
648Asynchronously read the symlink specified by C<$path> and pass it to 793Asynchronously read the symlink specified by C<$path> and pass it to
649the callback. If an error occurs, nothing or undef gets passed to the 794the callback. If an error occurs, nothing or undef gets passed to the
650callback. 795callback.
651 796
652 797
653=item aio_realpath $path, $callback->($path) 798=item aio_realpath $pathname, $callback->($path)
654 799
655Asynchronously make the path absolute and resolve any symlinks in 800Asynchronously make the path absolute and resolve any symlinks in
656C<$path>. The resulting path only consists of directories (Same as 801C<$path>. The resulting path only consists of directories (same as
657L<Cwd::realpath>). 802L<Cwd::realpath>).
658 803
659This request can be used to get the absolute path of the current working 804This request can be used to get the absolute path of the current working
660directory by passing it a path of F<.> (a single dot). 805directory by passing it a path of F<.> (a single dot).
661 806
662 807
663=item aio_rename $srcpath, $dstpath, $callback->($status) 808=item aio_rename $srcpath, $dstpath, $callback->($status)
664 809
665Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 810Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
666rename(2) and call the callback with the result code. 811rename(2) and call the callback with the result code.
812
813On systems that support the AIO::WD working directory abstraction
814natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
815of failing, C<rename> is called on the absolute path of C<$wd>.
816
817
818=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
819
820Basically a version of C<aio_rename> with an additional C<$flags>
821argument. Calling this with C<$flags=0> is the same as calling
822C<aio_rename>.
823
824Non-zero flags are currently only supported on GNU/Linux systems that
825support renameat2. Other systems fail with C<ENOSYS> in this case.
826
827The following constants are available (missing ones are, as usual C<0>),
828see renameat2(2) for details:
829
830C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
831and C<IO::AIO::RENAME_WHITEOUT>.
667 832
668 833
669=item aio_mkdir $pathname, $mode, $callback->($status) 834=item aio_mkdir $pathname, $mode, $callback->($status)
670 835
671Asynchronously mkdir (create) a directory and call the callback with 836Asynchronously mkdir (create) a directory and call the callback with
675 840
676=item aio_rmdir $pathname, $callback->($status) 841=item aio_rmdir $pathname, $callback->($status)
677 842
678Asynchronously rmdir (delete) a directory and call the callback with the 843Asynchronously rmdir (delete) a directory and call the callback with the
679result code. 844result code.
845
846On systems that support the AIO::WD working directory abstraction
847natively, the case C<[$wd, "."]> is specialcased - instead of failing,
848C<rmdir> is called on the absolute path of C<$wd>.
680 849
681 850
682=item aio_readdir $pathname, $callback->($entries) 851=item aio_readdir $pathname, $callback->($entries)
683 852
684Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 853Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
753C<$type>'s are known, which can be used to speed up some algorithms. 922C<$type>'s are known, which can be used to speed up some algorithms.
754 923
755=back 924=back
756 925
757 926
758=item aio_load $path, $data, $callback->($status) 927=item aio_load $pathname, $data, $callback->($status)
759 928
760This is a composite request that tries to fully load the given file into 929This is a composite request that tries to fully load the given file into
761memory. Status is the same as with aio_read. 930memory. Status is the same as with aio_read.
762 931
763=cut 932=cut
898 }; 1067 };
899 1068
900 $grp 1069 $grp
901} 1070}
902 1071
903=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 1072=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
904 1073
905Scans a directory (similar to C<aio_readdir>) but additionally tries to 1074Scans a directory (similar to C<aio_readdir>) but additionally tries to
906efficiently separate the entries of directory C<$path> into two sets of 1075efficiently separate the entries of directory C<$path> into two sets of
907names, directories you can recurse into (directories), and ones you cannot 1076names, directories you can recurse into (directories), and ones you cannot
908recurse into (everything else, including symlinks to directories). 1077recurse into (everything else, including symlinks to directories).
965 1134
966 my $grp = aio_group $cb; 1135 my $grp = aio_group $cb;
967 1136
968 $maxreq = 4 if $maxreq <= 0; 1137 $maxreq = 4 if $maxreq <= 0;
969 1138
970 # stat once 1139 # get a wd object
971 aioreq_pri $pri; 1140 aioreq_pri $pri;
972 add $grp aio_stat $path, sub { 1141 add $grp aio_wd $path, sub {
1142 $_[0]
973 return $grp->result () if $_[0]; 1143 or return $grp->result ();
974 my $now = time;
975 my $hash1 = join ":", (stat _)[0,1,3,7,9];
976 1144
977 # read the directory entries 1145 my $wd = [shift, "."];
1146
1147 # stat once
978 aioreq_pri $pri; 1148 aioreq_pri $pri;
979 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 1149 add $grp aio_stat $wd, sub {
980 my $entries = shift
981 or return $grp->result (); 1150 return $grp->result () if $_[0];
1151 my $now = time;
1152 my $hash1 = join ":", (stat _)[0,1,3,7,9];
982 1153
983 # stat the dir another time 1154 # read the directory entries
984 aioreq_pri $pri; 1155 aioreq_pri $pri;
1156 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
1157 my $entries = shift
1158 or return $grp->result ();
1159
1160 # stat the dir another time
1161 aioreq_pri $pri;
985 add $grp aio_stat $path, sub { 1162 add $grp aio_stat $wd, sub {
986 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1163 my $hash2 = join ":", (stat _)[0,1,3,7,9];
987 1164
988 my $ndirs; 1165 my $ndirs;
989 1166
990 # take the slow route if anything looks fishy 1167 # take the slow route if anything looks fishy
991 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1168 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
992 $ndirs = -1; 1169 $ndirs = -1;
993 } else { 1170 } else {
994 # if nlink == 2, we are finished 1171 # if nlink == 2, we are finished
995 # for non-posix-fs's, we rely on nlink < 2 1172 # for non-posix-fs's, we rely on nlink < 2
996 $ndirs = (stat _)[3] - 2 1173 $ndirs = (stat _)[3] - 2
997 or return $grp->result ([], $entries); 1174 or return $grp->result ([], $entries);
998 } 1175 }
999 1176
1000 my (@dirs, @nondirs); 1177 my (@dirs, @nondirs);
1001 1178
1002 my $statgrp = add $grp aio_group sub { 1179 my $statgrp = add $grp aio_group sub {
1003 $grp->result (\@dirs, \@nondirs); 1180 $grp->result (\@dirs, \@nondirs);
1004 }; 1181 };
1005 1182
1006 limit $statgrp $maxreq; 1183 limit $statgrp $maxreq;
1007 feed $statgrp sub { 1184 feed $statgrp sub {
1008 return unless @$entries; 1185 return unless @$entries;
1009 my $entry = shift @$entries; 1186 my $entry = shift @$entries;
1010 1187
1011 aioreq_pri $pri; 1188 aioreq_pri $pri;
1189 $wd->[1] = "$entry/.";
1012 add $statgrp aio_stat "$path/$entry/.", sub { 1190 add $statgrp aio_stat $wd, sub {
1013 if ($_[0] < 0) { 1191 if ($_[0] < 0) {
1014 push @nondirs, $entry; 1192 push @nondirs, $entry;
1015 } else { 1193 } else {
1016 # need to check for real directory 1194 # need to check for real directory
1017 aioreq_pri $pri; 1195 aioreq_pri $pri;
1196 $wd->[1] = $entry;
1018 add $statgrp aio_lstat "$path/$entry", sub { 1197 add $statgrp aio_lstat $wd, sub {
1019 if (-d _) { 1198 if (-d _) {
1020 push @dirs, $entry; 1199 push @dirs, $entry;
1021 1200
1022 unless (--$ndirs) { 1201 unless (--$ndirs) {
1023 push @nondirs, @$entries; 1202 push @nondirs, @$entries;
1024 feed $statgrp; 1203 feed $statgrp;
1204 }
1205 } else {
1206 push @nondirs, $entry;
1025 } 1207 }
1026 } else {
1027 push @nondirs, $entry;
1028 } 1208 }
1029 } 1209 }
1030 } 1210 };
1031 }; 1211 };
1032 }; 1212 };
1033 }; 1213 };
1034 }; 1214 };
1035 }; 1215 };
1036 1216
1037 $grp 1217 $grp
1038} 1218}
1039 1219
1040=item aio_rmtree $path, $callback->($status) 1220=item aio_rmtree $pathname, $callback->($status)
1041 1221
1042Delete a directory tree starting (and including) C<$path>, return the 1222Delete a directory tree starting (and including) C<$path>, return the
1043status of the final C<rmdir> only. This is a composite request that 1223status of the final C<rmdir> only. This is a composite request that
1044uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1224uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1045everything else. 1225everything else.
1046 1226
1047=cut 1227=cut
1048 1228
1070 }; 1250 };
1071 1251
1072 $grp 1252 $grp
1073} 1253}
1074 1254
1255=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1256
1257=item aio_ioctl $fh, $request, $buf, $callback->($status)
1258
1259These work just like the C<fcntl> and C<ioctl> built-in functions, except
1260they execute asynchronously and pass the return value to the callback.
1261
1262Both calls can be used for a lot of things, some of which make more sense
1263to run asynchronously in their own thread, while some others make less
1264sense. For example, calls that block waiting for external events, such
1265as locking, will also lock down an I/O thread while it is waiting, which
1266can deadlock the whole I/O system. At the same time, there might be no
1267alternative to using a thread to wait.
1268
1269So in general, you should only use these calls for things that do
1270(filesystem) I/O, not for things that wait for other events (network,
1271other processes), although if you are careful and know what you are doing,
1272you still can.
1273
1274The following constants are available (missing ones are, as usual C<0>):
1275
1276C<F_DUPFD_CLOEXEC>,
1277
1278C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1279
1280C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1281
1282C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1283C<FS_IOC_FIEMAP>.
1284
1285C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1286C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1287
1288C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1289C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1290C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1291C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1292C<FS_FL_USER_MODIFIABLE>.
1293
1294C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1295C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1296C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1297C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1298
1075=item aio_sync $callback->($status) 1299=item aio_sync $callback->($status)
1076 1300
1077Asynchronously call sync and call the callback when finished. 1301Asynchronously call sync and call the callback when finished.
1078 1302
1079=item aio_fsync $fh, $callback->($status) 1303=item aio_fsync $fh, $callback->($status)
1106C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, 1330C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1107C<IO::AIO::SYNC_FILE_RANGE_WRITE> and 1331C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1108C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range 1332C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1109manpage for details. 1333manpage for details.
1110 1334
1111=item aio_pathsync $path, $callback->($status) 1335=item aio_pathsync $pathname, $callback->($status)
1112 1336
1113This request tries to open, fsync and close the given path. This is a 1337This request tries to open, fsync and close the given path. This is a
1114composite request intended to sync directories after directory operations 1338composite request intended to sync directories after directory operations
1115(E.g. rename). This might not work on all operating systems or have any 1339(E.g. rename). This might not work on all operating systems or have any
1116specific effect, but usually it makes sure that directory changes get 1340specific effect, but usually it makes sure that directory changes get
1147 }; 1371 };
1148 1372
1149 $grp 1373 $grp
1150} 1374}
1151 1375
1152=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1376=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1153 1377
1154This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1378This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1155scalars (see the C<IO::AIO::mmap> function, although it also works on data 1379scalars (see the C<IO::AIO::mmap> function, although it also works on data
1156scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1380scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1157scalar must only be modified in-place while an aio operation is pending on 1381scalar must only be modified in-place while an aio operation is pending on
1159 1383
1160It calls the C<msync> function of your OS, if available, with the memory 1384It calls the C<msync> function of your OS, if available, with the memory
1161area starting at C<$offset> in the string and ending C<$length> bytes 1385area starting at C<$offset> in the string and ending C<$length> bytes
1162later. If C<$length> is negative, counts from the end, and if C<$length> 1386later. If C<$length> is negative, counts from the end, and if C<$length>
1163is C<undef>, then it goes till the end of the string. The flags can be 1387is C<undef>, then it goes till the end of the string. The flags can be
1164a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1388either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1165C<IO::AIO::MS_SYNC>. 1389C<IO::AIO::MS_INVALIDATE>.
1166 1390
1167=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1391=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1168 1392
1169This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1393This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1170scalars. 1394scalars.
1171 1395
1172It touches (reads or writes) all memory pages in the specified 1396It touches (reads or writes) all memory pages in the specified
1173range inside the scalar. All caveats and parameters are the same 1397range inside the scalar. All caveats and parameters are the same
1174as for C<aio_msync>, above, except for flags, which must be either 1398as for C<aio_msync>, above, except for flags, which must be either
1175C<0> (which reads all pages and ensures they are instantiated) or 1399C<0> (which reads all pages and ensures they are instantiated) or
1176C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1400C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1177writing an octet from it, which dirties the page). 1401writing an octet from it, which dirties the page).
1178 1402
1179=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1403=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1180 1404
1181This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1405This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1212documented under L<MISCELLANEOUS FUNCTIONS>. 1436documented under L<MISCELLANEOUS FUNCTIONS>.
1213 1437
1214Example: asynchronously lock all current and future pages into memory. 1438Example: asynchronously lock all current and future pages into memory.
1215 1439
1216 aio_mlockall IO::AIO::MCL_FUTURE; 1440 aio_mlockall IO::AIO::MCL_FUTURE;
1441
1442=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1443
1444Queries the extents of the given file (by calling the Linux C<FIEMAP>
1445ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1446the ioctl is not available on your OS, then this request will fail with
1447C<ENOSYS>.
1448
1449C<$start> is the starting offset to query extents for, C<$length> is the
1450size of the range to query - if it is C<undef>, then the whole file will
1451be queried.
1452
1453C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1454C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1455exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1456the data portion.
1457
1458C<$count> is the maximum number of extent records to return. If it is
1459C<undef>, then IO::AIO queries all extents of the range. As a very special
1460case, if it is C<0>, then the callback receives the number of extents
1461instead of the extents themselves (which is unreliable, see below).
1462
1463If an error occurs, the callback receives no arguments. The special
1464C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1465
1466Otherwise, the callback receives an array reference with extent
1467structures. Each extent structure is an array reference itself, with the
1468following members:
1469
1470 [$logical, $physical, $length, $flags]
1471
1472Flags is any combination of the following flag values (typically either C<0>
1473or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1474
1475C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1476C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1477C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1478C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1479C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1480C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1481
1482At the time of this writing (Linux 3.2), this requets is unreliable unless
1483C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1484it to return all extents of a range for files with large number of
1485extents. The code works around all these issues if C<$count> is undef.
1217 1486
1218=item aio_group $callback->(...) 1487=item aio_group $callback->(...)
1219 1488
1220This is a very special aio request: Instead of doing something, it is a 1489This is a very special aio request: Instead of doing something, it is a
1221container for other aio requests, which is useful if you want to bundle 1490container for other aio requests, which is useful if you want to bundle
1258like sleep and file handle readable/writable, the overhead this creates is 1527like sleep and file handle readable/writable, the overhead this creates is
1259immense (it blocks a thread for a long time) so do not use this function 1528immense (it blocks a thread for a long time) so do not use this function
1260except to put your application under artificial I/O pressure. 1529except to put your application under artificial I/O pressure.
1261 1530
1262=back 1531=back
1532
1533
1534=head2 IO::AIO::WD - multiple working directories
1535
1536Your process only has one current working directory, which is used by all
1537threads. This makes it hard to use relative paths (some other component
1538could call C<chdir> at any time, and it is hard to control when the path
1539will be used by IO::AIO).
1540
1541One solution for this is to always use absolute paths. This usually works,
1542but can be quite slow (the kernel has to walk the whole path on every
1543access), and can also be a hassle to implement.
1544
1545Newer POSIX systems have a number of functions (openat, fdopendir,
1546futimensat and so on) that make it possible to specify working directories
1547per operation.
1548
1549For portability, and because the clowns who "designed", or shall I write,
1550perpetrated this new interface were obviously half-drunk, this abstraction
1551cannot be perfect, though.
1552
1553IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1554object. This object stores the canonicalised, absolute version of the
1555path, and on systems that allow it, also a directory file descriptor.
1556
1557Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1558or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1559object and a pathname instead (or the IO::AIO::WD object alone, which
1560gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1561IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1562to that IO::AIO::WD object.
1563
1564For example, to get a wd object for F</etc> and then stat F<passwd>
1565inside, you would write:
1566
1567 aio_wd "/etc", sub {
1568 my $etcdir = shift;
1569
1570 # although $etcdir can be undef on error, there is generally no reason
1571 # to check for errors here, as aio_stat will fail with ENOENT
1572 # when $etcdir is undef.
1573
1574 aio_stat [$etcdir, "passwd"], sub {
1575 # yay
1576 };
1577 };
1578
1579The fact that C<aio_wd> is a request and not a normal function shows that
1580creating an IO::AIO::WD object is itself a potentially blocking operation,
1581which is why it is done asynchronously.
1582
1583To stat the directory obtained with C<aio_wd> above, one could write
1584either of the following three request calls:
1585
1586 aio_lstat "/etc" , sub { ... # pathname as normal string
1587 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1588 aio_lstat $wd , sub { ... # shorthand for the previous
1589
1590As with normal pathnames, IO::AIO keeps a copy of the working directory
1591object and the pathname string, so you could write the following without
1592causing any issues due to C<$path> getting reused:
1593
1594 my $path = [$wd, undef];
1595
1596 for my $name (qw(abc def ghi)) {
1597 $path->[1] = $name;
1598 aio_stat $path, sub {
1599 # ...
1600 };
1601 }
1602
1603There are some caveats: when directories get renamed (or deleted), the
1604pathname string doesn't change, so will point to the new directory (or
1605nowhere at all), while the directory fd, if available on the system,
1606will still point to the original directory. Most functions accepting a
1607pathname will use the directory fd on newer systems, and the string on
1608older systems. Some functions (such as realpath) will always rely on the
1609string form of the pathname.
1610
1611So this functionality is mainly useful to get some protection against
1612C<chdir>, to easily get an absolute path out of a relative path for future
1613reference, and to speed up doing many operations in the same directory
1614(e.g. when stat'ing all files in a directory).
1615
1616The following functions implement this working directory abstraction:
1617
1618=over 4
1619
1620=item aio_wd $pathname, $callback->($wd)
1621
1622Asynchonously canonicalise the given pathname and convert it to an
1623IO::AIO::WD object representing it. If possible and supported on the
1624system, also open a directory fd to speed up pathname resolution relative
1625to this working directory.
1626
1627If something goes wrong, then C<undef> is passwd to the callback instead
1628of a working directory object and C<$!> is set appropriately. Since
1629passing C<undef> as working directory component of a pathname fails the
1630request with C<ENOENT>, there is often no need for error checking in the
1631C<aio_wd> callback, as future requests using the value will fail in the
1632expected way.
1633
1634=item IO::AIO::CWD
1635
1636This is a compiletime constant (object) that represents the process
1637current working directory.
1638
1639Specifying this object as working directory object for a pathname is as if
1640the pathname would be specified directly, without a directory object. For
1641example, these calls are functionally identical:
1642
1643 aio_stat "somefile", sub { ... };
1644 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1645
1646=back
1647
1648To recover the path associated with an IO::AIO::WD object, you can use
1649C<aio_realpath>:
1650
1651 aio_realpath $wd, sub {
1652 warn "path is $_[0]\n";
1653 };
1654
1655Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1656sometimes, fall back to using an absolue path.
1263 1657
1264=head2 IO::AIO::REQ CLASS 1658=head2 IO::AIO::REQ CLASS
1265 1659
1266All non-aggregate C<aio_*> functions return an object of this class when 1660All non-aggregate C<aio_*> functions return an object of this class when
1267called in non-void context. 1661called in non-void context.
1385 1779
1386Sets a feeder/generator on this group: every group can have an attached 1780Sets a feeder/generator on this group: every group can have an attached
1387generator that generates requests if idle. The idea behind this is that, 1781generator that generates requests if idle. The idea behind this is that,
1388although you could just queue as many requests as you want in a group, 1782although you could just queue as many requests as you want in a group,
1389this might starve other requests for a potentially long time. For example, 1783this might starve other requests for a potentially long time. For example,
1390C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1784C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1391delaying any later requests for a long time. 1785requests, delaying any later requests for a long time.
1392 1786
1393To avoid this, and allow incremental generation of requests, you can 1787To avoid this, and allow incremental generation of requests, you can
1394instead a group and set a feeder on it that generates those requests. The 1788instead a group and set a feeder on it that generates those requests. The
1395feed callback will be called whenever there are few enough (see C<limit>, 1789feed callback will be called whenever there are few enough (see C<limit>,
1396below) requests active in the group itself and is expected to queue more 1790below) requests active in the group itself and is expected to queue more
1445 1839
1446See C<poll_cb> for an example. 1840See C<poll_cb> for an example.
1447 1841
1448=item IO::AIO::poll_cb 1842=item IO::AIO::poll_cb
1449 1843
1450Process some outstanding events on the result pipe. You have to call 1844Process some requests that have reached the result phase (i.e. they have
1845been executed but the results are not yet reported). You have to call
1846this "regularly" to finish outstanding requests.
1847
1451this regularly. Returns C<0> if all events could be processed (or there 1848Returns C<0> if all events could be processed (or there were no
1452were no events to process), or C<-1> if it returned earlier for whatever 1849events to process), or C<-1> if it returned earlier for whatever
1453reason. Returns immediately when no events are outstanding. The amount of 1850reason. Returns immediately when no events are outstanding. The amount
1454events processed depends on the settings of C<IO::AIO::max_poll_req> and 1851of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1455C<IO::AIO::max_poll_time>. 1852C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1456 1853
1457If not all requests were processed for whatever reason, the filehandle 1854If not all requests were processed for whatever reason, the poll file
1458will still be ready when C<poll_cb> returns, so normally you don't have to 1855descriptor will still be ready when C<poll_cb> returns, so normally you
1459do anything special to have it called later. 1856don't have to do anything special to have it called later.
1460 1857
1461Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1858Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1462ready, it can be beneficial to call this function from loops which submit 1859ready, it can be beneficial to call this function from loops which submit
1463a lot of requests, to make sure the results get processed when they become 1860a lot of requests, to make sure the results get processed when they become
1464available and not just when the loop is finished and the event loop takes 1861available and not just when the loop is finished and the event loop takes
1473 poll => 'r', async => 1, 1870 poll => 'r', async => 1,
1474 cb => \&IO::AIO::poll_cb); 1871 cb => \&IO::AIO::poll_cb);
1475 1872
1476=item IO::AIO::poll_wait 1873=item IO::AIO::poll_wait
1477 1874
1478If there are any outstanding requests and none of them in the result 1875Wait until either at least one request is in the result phase or no
1479phase, wait till the result filehandle becomes ready for reading (simply 1876requests are outstanding anymore.
1480does a C<select> on the filehandle. This is useful if you want to 1877
1481synchronously wait for some requests to finish). 1878This is useful if you want to synchronously wait for some requests to
1879become ready, without actually handling them.
1482 1880
1483See C<nreqs> for an example. 1881See C<nreqs> for an example.
1484 1882
1485=item IO::AIO::poll 1883=item IO::AIO::poll
1486 1884
1607 2005
1608This is a very bad function to use in interactive programs because it 2006This is a very bad function to use in interactive programs because it
1609blocks, and a bad way to reduce concurrency because it is inexact: Better 2007blocks, and a bad way to reduce concurrency because it is inexact: Better
1610use an C<aio_group> together with a feed callback. 2008use an C<aio_group> together with a feed callback.
1611 2009
1612It's main use is in scripts without an event loop - when you want to stat 2010Its main use is in scripts without an event loop - when you want to stat
1613a lot of files, you can write somehting like this: 2011a lot of files, you can write somehting like this:
1614 2012
1615 IO::AIO::max_outstanding 32; 2013 IO::AIO::max_outstanding 32;
1616 2014
1617 for my $path (...) { 2015 for my $path (...) {
1657 2055
1658=back 2056=back
1659 2057
1660=head3 MISCELLANEOUS FUNCTIONS 2058=head3 MISCELLANEOUS FUNCTIONS
1661 2059
1662IO::AIO implements some functions that might be useful, but are not 2060IO::AIO implements some functions that are useful when you want to use
1663asynchronous. 2061some "Advanced I/O" function not available to in Perl, without going the
2062"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2063counterpart.
1664 2064
1665=over 4 2065=over 4
1666 2066
1667=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2067=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1668 2068
1687=item IO::AIO::madvise $scalar, $offset, $len, $advice 2087=item IO::AIO::madvise $scalar, $offset, $len, $advice
1688 2088
1689Simply calls the C<posix_madvise> function (see its 2089Simply calls the C<posix_madvise> function (see its
1690manpage for details). The following advice constants are 2090manpage for details). The following advice constants are
1691available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2091available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1692C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2092C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2093C<IO::AIO::MADV_DONTNEED>.
2094
2095If C<$offset> is negative, counts from the end. If C<$length> is negative,
2096the remaining length of the C<$scalar> is used. If possible, C<$length>
2097will be reduced to fit into the C<$scalar>.
1693 2098
1694On systems that do not implement C<posix_madvise>, this function returns 2099On systems that do not implement C<posix_madvise>, this function returns
1695ENOSYS, otherwise the return value of C<posix_madvise>. 2100ENOSYS, otherwise the return value of C<posix_madvise>.
1696 2101
1697=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2102=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1699Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2104Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1700$scalar (see its manpage for details). The following protect 2105$scalar (see its manpage for details). The following protect
1701constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2106constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1702C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2107C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1703 2108
2109If C<$offset> is negative, counts from the end. If C<$length> is negative,
2110the remaining length of the C<$scalar> is used. If possible, C<$length>
2111will be reduced to fit into the C<$scalar>.
2112
1704On systems that do not implement C<mprotect>, this function returns 2113On systems that do not implement C<mprotect>, this function returns
1705ENOSYS, otherwise the return value of C<mprotect>. 2114ENOSYS, otherwise the return value of C<mprotect>.
1706 2115
1707=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2116=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1708 2117
1709Memory-maps a file (or anonymous memory range) and attaches it to the 2118Memory-maps a file (or anonymous memory range) and attaches it to the
1710given C<$scalar>, which will act like a string scalar. 2119given C<$scalar>, which will act like a string scalar. Returns true on
2120success, and false otherwise.
1711 2121
2122The scalar must exist, but its contents do not matter - this means you
2123cannot use a nonexistant array or hash element. When in doubt, C<undef>
2124the scalar first.
2125
1712The only operations allowed on the scalar are C<substr>/C<vec> that don't 2126The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1713change the string length, and most read-only operations such as copying it 2127which don't change the string length, and most read-only operations such
1714or searching it with regexes and so on. 2128as copying it or searching it with regexes and so on.
1715 2129
1716Anything else is unsafe and will, at best, result in memory leaks. 2130Anything else is unsafe and will, at best, result in memory leaks.
1717 2131
1718The memory map associated with the C<$scalar> is automatically removed 2132The memory map associated with the C<$scalar> is automatically removed
1719when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2133when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1720C<IO::AIO::munmap> functions are called. 2134or C<IO::AIO::munmap> functions are called on it.
1721 2135
1722This calls the C<mmap>(2) function internally. See your system's manual 2136This calls the C<mmap>(2) function internally. See your system's manual
1723page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2137page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1724 2138
1725The C<$length> must be larger than zero and smaller than the actual 2139The C<$length> must be larger than zero and smaller than the actual
1726filesize. 2140filesize.
1727 2141
1728C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2142C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1729C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2143C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1730 2144
1731C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2145C<$flags> can be a combination of
1732C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2146C<IO::AIO::MAP_SHARED> or
1733not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2147C<IO::AIO::MAP_PRIVATE>,
2148or a number of system-specific flags (when not available, the are C<0>):
1734(which is set to C<MAP_ANON> if your system only provides this 2149C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1735constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2150C<IO::AIO::MAP_LOCKED>,
1736C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2151C<IO::AIO::MAP_NORESERVE>,
2152C<IO::AIO::MAP_POPULATE>,
1737C<IO::AIO::MAP_NONBLOCK> 2153C<IO::AIO::MAP_NONBLOCK>,
2154C<IO::AIO::MAP_FIXED>,
2155C<IO::AIO::MAP_GROWSDOWN>,
2156C<IO::AIO::MAP_32BIT>,
2157C<IO::AIO::MAP_HUGETLB> or
2158C<IO::AIO::MAP_STACK>.
1738 2159
1739If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2160If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1740 2161
1741C<$offset> is the offset from the start of the file - it generally must be 2162C<$offset> is the offset from the start of the file - it generally must be
1742a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2163a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1767 2188
1768Calls the C<munlockall> function. 2189Calls the C<munlockall> function.
1769 2190
1770On systems that do not implement C<munlockall>, this function returns 2191On systems that do not implement C<munlockall>, this function returns
1771ENOSYS, otherwise the return value of C<munlockall>. 2192ENOSYS, otherwise the return value of C<munlockall>.
2193
2194=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2195
2196Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2197C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2198should be the file offset.
2199
2200C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2201silently corrupt the data in this case.
2202
2203The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2204C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2205C<IO::AIO::SPLICE_F_GIFT>.
2206
2207See the C<splice(2)> manpage for details.
2208
2209=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2210
2211Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2212description for C<IO::AIO::splice> above for details.
2213
2214=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2215
2216Attempts to query or change the pipe buffer size. Obviously works only
2217on pipes, and currently works only on GNU/Linux systems, and fails with
2218C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2219size on other systems, drop me a note.
2220
2221=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2222
2223This is a direct interface to the Linux L<pipe2(2)> system call. If
2224C<$flags> is missing or C<0>, then this should be the same as a call to
2225perl's built-in C<pipe> function and create a new pipe, and works on
2226systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2227(..., 4096, O_BINARY)>.
2228
2229If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2230the given flags (Linux 2.6.27, glibc 2.9).
2231
2232On success, the read and write file handles are returned.
2233
2234On error, nothing will be returned. If the pipe2 syscall is missing and
2235C<$flags> is non-zero, fails with C<ENOSYS>.
2236
2237Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2238time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2239C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1772 2240
1773=back 2241=back
1774 2242
1775=cut 2243=cut
1776 2244

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