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Revision 1.229 by root, Wed Jul 25 16:32:30 2012 UTC vs.
Revision 1.313 by root, Sat Sep 4 21:21:14 2021 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 = '4.15'; 176 our $VERSION = 4.76;
174 177
175 our @AIO_REQ = qw(aio_sendfile aio_seek 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 aio_fiemap 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
188 aio_slurp
185 aio_wd); 189 aio_wd);
186 190
187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 191 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
189 min_parallel max_parallel max_idle idle_timeout 193 min_parallel max_parallel max_idle idle_timeout
190 nreqs nready npending nthreads 194 nreqs nready npending nthreads
191 max_poll_time max_poll_reqs 195 max_poll_time max_poll_reqs
192 sendfile fadvise madvise 196 sendfile fadvise madvise
193 mmap munmap munlock munlockall); 197 mmap munmap mremap munlock munlockall);
194 198
195 push @AIO_REQ, qw(aio_busy); # not exported 199 push @AIO_REQ, qw(aio_busy); # not exported
196 200
197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 201 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
198 202
… …
202 206
203=head1 FUNCTIONS 207=head1 FUNCTIONS
204 208
205=head2 QUICK OVERVIEW 209=head2 QUICK OVERVIEW
206 210
207This section simply lists the prototypes of the most important functions 211This section simply lists the prototypes most of the functions for
208for quick reference. See the following sections for function-by-function 212quick reference. See the following sections for function-by-function
209documentation. 213documentation.
210 214
211 aio_wd $pathname, $callback->($wd) 215 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh) 216 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status) 217 aio_close $fh, $callback->($status)
… …
222 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 226 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
223 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 227 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 228 aio_chmod $fh_or_path, $mode, $callback->($status)
225 aio_truncate $fh_or_path, $offset, $callback->($status) 229 aio_truncate $fh_or_path, $offset, $callback->($status)
226 aio_allocate $fh, $mode, $offset, $len, $callback->($status) 230 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
231 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
227 aio_unlink $pathname, $callback->($status) 232 aio_unlink $pathname, $callback->($status)
228 aio_mknod $pathname, $mode, $dev, $callback->($status) 233 aio_mknod $pathname, $mode, $dev, $callback->($status)
229 aio_link $srcpath, $dstpath, $callback->($status) 234 aio_link $srcpath, $dstpath, $callback->($status)
230 aio_symlink $srcpath, $dstpath, $callback->($status) 235 aio_symlink $srcpath, $dstpath, $callback->($status)
231 aio_readlink $pathname, $callback->($link) 236 aio_readlink $pathname, $callback->($link)
232 aio_realpath $pathname, $callback->($link) 237 aio_realpath $pathname, $callback->($path)
233 aio_rename $srcpath, $dstpath, $callback->($status) 238 aio_rename $srcpath, $dstpath, $callback->($status)
239 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
234 aio_mkdir $pathname, $mode, $callback->($status) 240 aio_mkdir $pathname, $mode, $callback->($status)
235 aio_rmdir $pathname, $callback->($status) 241 aio_rmdir $pathname, $callback->($status)
236 aio_readdir $pathname, $callback->($entries) 242 aio_readdir $pathname, $callback->($entries)
237 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 243 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
238 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 244 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
… …
240 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 246 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
241 aio_load $pathname, $data, $callback->($status) 247 aio_load $pathname, $data, $callback->($status)
242 aio_copy $srcpath, $dstpath, $callback->($status) 248 aio_copy $srcpath, $dstpath, $callback->($status)
243 aio_move $srcpath, $dstpath, $callback->($status) 249 aio_move $srcpath, $dstpath, $callback->($status)
244 aio_rmtree $pathname, $callback->($status) 250 aio_rmtree $pathname, $callback->($status)
251 aio_fcntl $fh, $cmd, $arg, $callback->($status)
252 aio_ioctl $fh, $request, $buf, $callback->($status)
245 aio_sync $callback->($status) 253 aio_sync $callback->($status)
246 aio_syncfs $fh, $callback->($status) 254 aio_syncfs $fh, $callback->($status)
247 aio_fsync $fh, $callback->($status) 255 aio_fsync $fh, $callback->($status)
248 aio_fdatasync $fh, $callback->($status) 256 aio_fdatasync $fh, $callback->($status)
249 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 257 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
250 aio_pathsync $pathname, $callback->($status) 258 aio_pathsync $pathname, $callback->($status)
251 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
252 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 260 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
253 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 261 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
254 aio_mlockall $flags, $callback->($status) 262 aio_mlockall $flags, $callback->($status)
255 aio_group $callback->(...) 263 aio_group $callback->(...)
256 aio_nop $callback->() 264 aio_nop $callback->()
… …
270 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
271 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
272 IO::AIO::nreqs 280 IO::AIO::nreqs
273 IO::AIO::nready 281 IO::AIO::nready
274 IO::AIO::npending 282 IO::AIO::npending
283 IO::AIO::reinit
284
285 $nfd = IO::AIO::get_fdlimit
286 IO::AIO::min_fdlimit $nfd
275 287
276 IO::AIO::sendfile $ofh, $ifh, $offset, $count 288 IO::AIO::sendfile $ofh, $ifh, $offset, $count
277 IO::AIO::fadvise $fh, $offset, $len, $advice 289 IO::AIO::fadvise $fh, $offset, $len, $advice
290
278 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 291 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
279 IO::AIO::munmap $scalar 292 IO::AIO::munmap $scalar
293 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
280 IO::AIO::madvise $scalar, $offset, $length, $advice 294 IO::AIO::madvise $scalar, $offset, $length, $advice
281 IO::AIO::mprotect $scalar, $offset, $length, $protect 295 IO::AIO::mprotect $scalar, $offset, $length, $protect
282 IO::AIO::munlock $scalar, $offset = 0, $length = undef 296 IO::AIO::munlock $scalar, $offset = 0, $length = undef
283 IO::AIO::munlockall 297 IO::AIO::munlockall
298
299 # stat extensions
300 $counter = IO::AIO::st_gen
301 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
302 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
303 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
304 $seconds = IO::AIO::st_btimesec
305 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
306
307 # very much unportable syscalls
308 IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_len, $flags
309 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
310 IO::AIO::tee $r_fh, $w_fh, $length, $flags
311 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
312 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
313 $fh = IO::AIO::memfd_create $pathname[, $flags]
314 $fh = IO::AIO::eventfd [$initval, [$flags]]
315 $fh = IO::AIO::timerfd_create $clockid[, $flags]
316 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
317 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
284 318
285=head2 API NOTES 319=head2 API NOTES
286 320
287All the C<aio_*> calls are more or less thin wrappers around the syscall 321All the C<aio_*> calls are more or less thin wrappers around the syscall
288with the same name (sans C<aio_>). The arguments are similar or identical, 322with the same name (sans C<aio_>). The arguments are similar or identical,
… …
361 395
362 396
363=item aio_open $pathname, $flags, $mode, $callback->($fh) 397=item aio_open $pathname, $flags, $mode, $callback->($fh)
364 398
365Asynchronously open or create a file and call the callback with a newly 399Asynchronously open or create a file and call the callback with a newly
366created filehandle for the file. 400created filehandle for the file (or C<undef> in case of an error).
367 401
368The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 402The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
369for an explanation. 403for an explanation.
370 404
371The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 405The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
… …
394following POSIX and non-POSIX constants are available (missing ones on 428following POSIX and non-POSIX constants are available (missing ones on
395your system are, as usual, C<0>): 429your system are, as usual, C<0>):
396 430
397C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 431C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
398C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 432C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
399C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 433C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
400 434
401 435
402=item aio_close $fh, $callback->($status) 436=item aio_close $fh, $callback->($status)
403 437
404Asynchronously close a file and call the callback with the result 438Asynchronously close a file and call the callback with the result
… …
439=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 473=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
440 474
441=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 475=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
442 476
443Reads or writes C<$length> bytes from or to the specified C<$fh> and 477Reads or writes C<$length> bytes from or to the specified C<$fh> and
444C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 478C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
445and calls the callback without the actual number of bytes read (or -1 on 479calls the callback with the actual number of bytes transferred (or -1 on
446error, just like the syscall). 480error, just like the syscall).
447 481
448C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 482C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
449offset plus the actual number of bytes read. 483offset plus the actual number of bytes read.
450 484
… …
508As native sendfile syscalls (as practically any non-POSIX interface hacked 542As native sendfile syscalls (as practically any non-POSIX interface hacked
509together in a hurry to improve benchmark numbers) tend to be rather buggy 543together in a hurry to improve benchmark numbers) tend to be rather buggy
510on many systems, this implementation tries to work around some known bugs 544on many systems, this implementation tries to work around some known bugs
511in Linux and FreeBSD kernels (probably others, too), but that might fail, 545in Linux and FreeBSD kernels (probably others, too), but that might fail,
512so you really really should check the return value of C<aio_sendfile> - 546so you really really should check the return value of C<aio_sendfile> -
513fewre bytes than expected might have been transferred. 547fewer bytes than expected might have been transferred.
514 548
515 549
516=item aio_readahead $fh,$offset,$length, $callback->($retval) 550=item aio_readahead $fh,$offset,$length, $callback->($retval)
517 551
518C<aio_readahead> populates the page cache with data from a file so that 552C<aio_readahead> populates the page cache with data from a file so that
… …
522whole pages, so that offset is effectively rounded down to a page boundary 556whole pages, so that offset is effectively rounded down to a page boundary
523and bytes are read up to the next page boundary greater than or equal to 557and bytes are read up to the next page boundary greater than or equal to
524(off-set+length). C<aio_readahead> does not read beyond the end of the 558(off-set+length). C<aio_readahead> does not read beyond the end of the
525file. The current file offset of the file is left unchanged. 559file. The current file offset of the file is left unchanged.
526 560
527If that syscall doesn't exist (likely if your OS isn't Linux) it will be 561If that syscall doesn't exist (likely if your kernel isn't Linux) it will
528emulated by simply reading the data, which would have a similar effect. 562be emulated by simply reading the data, which would have a similar effect.
529 563
530 564
531=item aio_stat $fh_or_path, $callback->($status) 565=item aio_stat $fh_or_path, $callback->($status)
532 566
533=item aio_lstat $fh, $callback->($status) 567=item aio_lstat $fh, $callback->($status)
534 568
535Works like perl's C<stat> or C<lstat> in void context. The callback will 569Works almost exactly like perl's C<stat> or C<lstat> in void context. The
536be called after the stat and the results will be available using C<stat _> 570callback will be called after the stat and the results will be available
537or C<-s _> etc... 571using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
572and C<-T>).
538 573
539The pathname passed to C<aio_stat> must be absolute. See API NOTES, above, 574The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
540for an explanation. 575for an explanation.
541 576
542Currently, the stats are always 64-bit-stats, i.e. instead of returning an 577Currently, the stats are always 64-bit-stats, i.e. instead of returning an
… …
549behaviour). 584behaviour).
550 585
551C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, 586C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
552C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, 587C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
553C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. 588C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
589
590To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
591ACCESS>.
554 592
555Example: Print the length of F</etc/passwd>: 593Example: Print the length of F</etc/passwd>:
556 594
557 aio_stat "/etc/passwd", sub { 595 aio_stat "/etc/passwd", sub {
558 $_[0] and die "stat failed: $!"; 596 $_[0] and die "stat failed: $!";
… …
602 namemax => 255, 640 namemax => 255,
603 frsize => 1024, 641 frsize => 1024,
604 fsid => 1810 642 fsid => 1810
605 } 643 }
606 644
607
608=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 645=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
609 646
610Works like perl's C<utime> function (including the special case of $atime 647Works like perl's C<utime> function (including the special case of $atime
611and $mtime being undef). Fractional times are supported if the underlying 648and $mtime being undef). Fractional times are supported if the underlying
612syscalls support them. 649syscalls support them.
613 650
614When called with a pathname, uses utimes(2) if available, otherwise 651When called with a pathname, uses utimensat(2) or utimes(2) if available,
615utime(2). If called on a file descriptor, uses futimes(2) if available, 652otherwise utime(2). If called on a file descriptor, uses futimens(2)
616otherwise returns ENOSYS, so this is not portable. 653or futimes(2) if available, otherwise returns ENOSYS, so this is not
654portable.
617 655
618Examples: 656Examples:
619 657
620 # set atime and mtime to current time (basically touch(1)): 658 # set atime and mtime to current time (basically touch(1)):
621 aio_utime "path", undef, undef; 659 aio_utime "path", undef, undef;
… …
641Works like truncate(2) or ftruncate(2). 679Works like truncate(2) or ftruncate(2).
642 680
643 681
644=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 682=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
645 683
646Allocates or freed disk space according to the C<$mode> argument. See the 684Allocates or frees disk space according to the C<$mode> argument. See the
647linux C<fallocate> docuemntation for details. 685linux C<fallocate> documentation for details.
648 686
649C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 687C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
650to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | 688space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
651IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range. 689to deallocate a file range.
690
691IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
692(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
693C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
694to unshare shared blocks (see your L<fallocate(2)> manpage).
652 695
653The file system block size used by C<fallocate> is presumably the 696The file system block size used by C<fallocate> is presumably the
654C<f_bsize> returned by C<statvfs>. 697C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
698can dictate other limitations.
655 699
656If C<fallocate> isn't available or cannot be emulated (currently no 700If C<fallocate> isn't available or cannot be emulated (currently no
657emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 701emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
658 702
659 703
… …
701 745
702 746
703=item aio_realpath $pathname, $callback->($path) 747=item aio_realpath $pathname, $callback->($path)
704 748
705Asynchronously make the path absolute and resolve any symlinks in 749Asynchronously make the path absolute and resolve any symlinks in
706C<$path>. The resulting path only consists of directories (Same as 750C<$path>. The resulting path only consists of directories (same as
707L<Cwd::realpath>). 751L<Cwd::realpath>).
708 752
709This request can be used to get the absolute path of the current working 753This request can be used to get the absolute path of the current working
710directory by passing it a path of F<.> (a single dot). 754directory by passing it a path of F<.> (a single dot).
711 755
712 756
713=item aio_rename $srcpath, $dstpath, $callback->($status) 757=item aio_rename $srcpath, $dstpath, $callback->($status)
714 758
715Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 759Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
716rename(2) and call the callback with the result code. 760rename(2) and call the callback with the result code.
761
762On systems that support the AIO::WD working directory abstraction
763natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
764of failing, C<rename> is called on the absolute path of C<$wd>.
765
766
767=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
768
769Basically a version of C<aio_rename> with an additional C<$flags>
770argument. Calling this with C<$flags=0> is the same as calling
771C<aio_rename>.
772
773Non-zero flags are currently only supported on GNU/Linux systems that
774support renameat2. Other systems fail with C<ENOSYS> in this case.
775
776The following constants are available (missing ones are, as usual C<0>),
777see renameat2(2) for details:
778
779C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
780and C<IO::AIO::RENAME_WHITEOUT>.
717 781
718 782
719=item aio_mkdir $pathname, $mode, $callback->($status) 783=item aio_mkdir $pathname, $mode, $callback->($status)
720 784
721Asynchronously mkdir (create) a directory and call the callback with 785Asynchronously mkdir (create) a directory and call the callback with
… …
726=item aio_rmdir $pathname, $callback->($status) 790=item aio_rmdir $pathname, $callback->($status)
727 791
728Asynchronously rmdir (delete) a directory and call the callback with the 792Asynchronously rmdir (delete) a directory and call the callback with the
729result code. 793result code.
730 794
795On systems that support the AIO::WD working directory abstraction
796natively, the case C<[$wd, "."]> is specialcased - instead of failing,
797C<rmdir> is called on the absolute path of C<$wd>.
798
731 799
732=item aio_readdir $pathname, $callback->($entries) 800=item aio_readdir $pathname, $callback->($entries)
733 801
734Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 802Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
735directory (i.e. opendir + readdir + closedir). The entries will not be 803directory (i.e. opendir + readdir + closedir). The entries will not be
… …
750 818
751=over 4 819=over 4
752 820
753=item IO::AIO::READDIR_DENTS 821=item IO::AIO::READDIR_DENTS
754 822
755When this flag is off, then the callback gets an arrayref consisting of 823Normally the callback gets an arrayref consisting of names only (as
756names only (as with C<aio_readdir>), otherwise it gets an arrayref with 824with C<aio_readdir>). If this flag is set, then the callback gets an
757C<[$name, $type, $inode]> arrayrefs, each describing a single directory 825arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
758entry in more detail. 826single directory entry in more detail:
759 827
760C<$name> is the name of the entry. 828C<$name> is the name of the entry.
761 829
762C<$type> is one of the C<IO::AIO::DT_xxx> constants: 830C<$type> is one of the C<IO::AIO::DT_xxx> constants:
763 831
764C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 832C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
765C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 833C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
766C<IO::AIO::DT_WHT>. 834C<IO::AIO::DT_WHT>.
767 835
768C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 836C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
769know, you have to run stat yourself. Also, for speed reasons, the C<$type> 837to know, you have to run stat yourself. Also, for speed/memory reasons,
770scalars are read-only: you can not modify them. 838the C<$type> scalars are read-only: you must not modify them.
771 839
772C<$inode> is the inode number (which might not be exact on systems with 64 840C<$inode> is the inode number (which might not be exact on systems with 64
773bit inode numbers and 32 bit perls). This field has unspecified content on 841bit inode numbers and 32 bit perls). This field has unspecified content on
774systems that do not deliver the inode information. 842systems that do not deliver the inode information.
775 843
… …
786short names are tried first. 854short names are tried first.
787 855
788=item IO::AIO::READDIR_STAT_ORDER 856=item IO::AIO::READDIR_STAT_ORDER
789 857
790When this flag is set, then the names will be returned in an order 858When this flag is set, then the names will be returned in an order
791suitable for stat()'ing each one. That is, when you plan to stat() 859suitable for stat()'ing each one. That is, when you plan to stat() most or
792all files in the given directory, then the returned order will likely 860all files in the given directory, then the returned order will likely be
793be fastest. 861faster.
794 862
795If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 863If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
796the likely dirs come first, resulting in a less optimal stat order. 864then the likely dirs come first, resulting in a less optimal stat order
865for stat'ing all entries, but likely a more optimal order for finding
866subdirectories.
797 867
798=item IO::AIO::READDIR_FOUND_UNKNOWN 868=item IO::AIO::READDIR_FOUND_UNKNOWN
799 869
800This flag should not be set when calling C<aio_readdirx>. Instead, it 870This flag should not be set when calling C<aio_readdirx>. Instead, it
801is being set by C<aio_readdirx>, when any of the C<$type>'s found were 871is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
803C<$type>'s are known, which can be used to speed up some algorithms. 873C<$type>'s are known, which can be used to speed up some algorithms.
804 874
805=back 875=back
806 876
807 877
878=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
879
880Opens, reads and closes the given file. The data is put into C<$data>,
881which is resized as required.
882
883If C<$offset> is negative, then it is counted from the end of the file.
884
885If C<$length> is zero, then the remaining length of the file is
886used. Also, in this case, the same limitations to modifying C<$data> apply
887as when IO::AIO::mmap is used, i.e. it must only be modified in-place
888with C<substr>. If the size of the file is known, specifying a non-zero
889C<$length> results in a performance advantage.
890
891This request is similar to the older C<aio_load> request, but since it is
892a single request, it might be more efficient to use.
893
894Example: load F</etc/passwd> into C<$passwd>.
895
896 my $passwd;
897 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
898 $_[0] >= 0
899 or die "/etc/passwd: $!\n";
900
901 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
902 print $passwd;
903 };
904 IO::AIO::flush;
905
906
808=item aio_load $pathname, $data, $callback->($status) 907=item aio_load $pathname, $data, $callback->($status)
809 908
810This is a composite request that tries to fully load the given file into 909This is a composite request that tries to fully load the given file into
811memory. Status is the same as with aio_read. 910memory. Status is the same as with aio_read.
911
912Using C<aio_slurp> might be more efficient, as it is a single request.
812 913
813=cut 914=cut
814 915
815sub aio_load($$;$) { 916sub aio_load($$;$) {
816 my ($path, undef, $cb) = @_; 917 my ($path, undef, $cb) = @_;
… …
836=item aio_copy $srcpath, $dstpath, $callback->($status) 937=item aio_copy $srcpath, $dstpath, $callback->($status)
837 938
838Try to copy the I<file> (directories not supported as either source or 939Try to copy the I<file> (directories not supported as either source or
839destination) from C<$srcpath> to C<$dstpath> and call the callback with 940destination) from C<$srcpath> to C<$dstpath> and call the callback with
840a status of C<0> (ok) or C<-1> (error, see C<$!>). 941a status of C<0> (ok) or C<-1> (error, see C<$!>).
942
943Existing destination files will be truncated.
841 944
842This is a composite request that creates the destination file with 945This is a composite request that creates the destination file with
843mode 0200 and copies the contents of the source file into it using 946mode 0200 and copies the contents of the source file into it using
844C<aio_sendfile>, followed by restoring atime, mtime, access mode and 947C<aio_sendfile>, followed by restoring atime, mtime, access mode and
845uid/gid, in that order. 948uid/gid, in that order.
… …
955Scans a directory (similar to C<aio_readdir>) but additionally tries to 1058Scans a directory (similar to C<aio_readdir>) but additionally tries to
956efficiently separate the entries of directory C<$path> into two sets of 1059efficiently separate the entries of directory C<$path> into two sets of
957names, directories you can recurse into (directories), and ones you cannot 1060names, directories you can recurse into (directories), and ones you cannot
958recurse into (everything else, including symlinks to directories). 1061recurse into (everything else, including symlinks to directories).
959 1062
960C<aio_scandir> is a composite request that creates of many sub requests_ 1063C<aio_scandir> is a composite request that generates many sub requests.
961C<$maxreq> specifies the maximum number of outstanding aio requests that 1064C<$maxreq> specifies the maximum number of outstanding aio requests that
962this function generates. If it is C<< <= 0 >>, then a suitable default 1065this function generates. If it is C<< <= 0 >>, then a suitable default
963will be chosen (currently 4). 1066will be chosen (currently 4).
964 1067
965On error, the callback is called without arguments, otherwise it receives 1068On error, the callback is called without arguments, otherwise it receives
… …
1029 aioreq_pri $pri; 1132 aioreq_pri $pri;
1030 add $grp aio_stat $wd, sub { 1133 add $grp aio_stat $wd, sub {
1031 return $grp->result () if $_[0]; 1134 return $grp->result () if $_[0];
1032 my $now = time; 1135 my $now = time;
1033 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1136 my $hash1 = join ":", (stat _)[0,1,3,7,9];
1137 my $rdxflags = READDIR_DIRS_FIRST;
1138
1139 if ((stat _)[3] < 2) {
1140 # at least one non-POSIX filesystem exists
1141 # that returns useful DT_type values: btrfs,
1142 # so optimise for this here by requesting dents
1143 $rdxflags |= READDIR_DENTS;
1144 }
1034 1145
1035 # read the directory entries 1146 # read the directory entries
1036 aioreq_pri $pri; 1147 aioreq_pri $pri;
1037 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1148 add $grp aio_readdirx $wd, $rdxflags, sub {
1038 my $entries = shift 1149 my ($entries, $flags) = @_
1039 or return $grp->result (); 1150 or return $grp->result ();
1151
1152 if ($rdxflags & READDIR_DENTS) {
1153 # if we requested type values, see if we can use them directly.
1154
1155 # if there were any DT_UNKNOWN entries then we assume we
1156 # don't know. alternatively, we could assume that if we get
1157 # one DT_DIR, then all directories are indeed marked with
1158 # DT_DIR, but this seems not required for btrfs, and this
1159 # is basically the "btrfs can't get it's act together" code
1160 # branch.
1161 unless ($flags & READDIR_FOUND_UNKNOWN) {
1162 # now we have valid DT_ information for all entries,
1163 # so use it as an optimisation without further stat's.
1164 # they must also all be at the beginning of @$entries
1165 # by now.
1166
1167 my $dirs;
1168
1169 if (@$entries) {
1170 for (0 .. $#$entries) {
1171 if ($entries->[$_][1] != DT_DIR) {
1172 # splice out directories
1173 $dirs = [splice @$entries, 0, $_];
1174 last;
1175 }
1176 }
1177
1178 # if we didn't find any non-dir, then all entries are dirs
1179 unless ($dirs) {
1180 ($dirs, $entries) = ($entries, []);
1181 }
1182 } else {
1183 # directory is empty, so there are no sbdirs
1184 $dirs = [];
1185 }
1186
1187 # either splice'd the directories out or the dir was empty.
1188 # convert dents to filenames
1189 $_ = $_->[0] for @$dirs;
1190 $_ = $_->[0] for @$entries;
1191
1192 return $grp->result ($dirs, $entries);
1193 }
1194
1195 # cannot use, so return to our old ways
1196 # by pretending we only scanned for names.
1197 $_ = $_->[0] for @$entries;
1198 }
1040 1199
1041 # stat the dir another time 1200 # stat the dir another time
1042 aioreq_pri $pri; 1201 aioreq_pri $pri;
1043 add $grp aio_stat $wd, sub { 1202 add $grp aio_stat $wd, sub {
1044 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1203 my $hash2 = join ":", (stat _)[0,1,3,7,9];
… …
1099} 1258}
1100 1259
1101=item aio_rmtree $pathname, $callback->($status) 1260=item aio_rmtree $pathname, $callback->($status)
1102 1261
1103Delete a directory tree starting (and including) C<$path>, return the 1262Delete a directory tree starting (and including) C<$path>, return the
1104status of the final C<rmdir> only. This is a composite request that 1263status of the final C<rmdir> only. This is a composite request that
1105uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1264uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1106everything else. 1265everything else.
1107 1266
1108=cut 1267=cut
1109 1268
… …
1130 add $grp $dirgrp; 1289 add $grp $dirgrp;
1131 }; 1290 };
1132 1291
1133 $grp 1292 $grp
1134} 1293}
1294
1295=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1296
1297=item aio_ioctl $fh, $request, $buf, $callback->($status)
1298
1299These work just like the C<fcntl> and C<ioctl> built-in functions, except
1300they execute asynchronously and pass the return value to the callback.
1301
1302Both calls can be used for a lot of things, some of which make more sense
1303to run asynchronously in their own thread, while some others make less
1304sense. For example, calls that block waiting for external events, such
1305as locking, will also lock down an I/O thread while it is waiting, which
1306can deadlock the whole I/O system. At the same time, there might be no
1307alternative to using a thread to wait.
1308
1309So in general, you should only use these calls for things that do
1310(filesystem) I/O, not for things that wait for other events (network,
1311other processes), although if you are careful and know what you are doing,
1312you still can.
1313
1314The following constants are available and can be used for normal C<ioctl>
1315and C<fcntl> as well (missing ones are, as usual C<0>):
1316
1317C<F_DUPFD_CLOEXEC>,
1318
1319C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1320
1321C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1322
1323C<F_ADD_SEALS>, C<F_GET_SEALS>, C<F_SEAL_SEAL>, C<F_SEAL_SHRINK>, C<F_SEAL_GROW> and
1324C<F_SEAL_WRITE>.
1325
1326C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1327C<FS_IOC_FIEMAP>.
1328
1329C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1330C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1331
1332C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1333C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1334C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1335C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1336C<FS_FL_USER_MODIFIABLE>.
1337
1338C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1339C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1340C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1341C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1135 1342
1136=item aio_sync $callback->($status) 1343=item aio_sync $callback->($status)
1137 1344
1138Asynchronously call sync and call the callback when finished. 1345Asynchronously call sync and call the callback when finished.
1139 1346
… …
1208 }; 1415 };
1209 1416
1210 $grp 1417 $grp
1211} 1418}
1212 1419
1213=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1420=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1214 1421
1215This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1422This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1216scalars (see the C<IO::AIO::mmap> function, although it also works on data 1423scalars (see the C<IO::AIO::mmap> function, although it also works on data
1217scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1424scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1218scalar must only be modified in-place while an aio operation is pending on 1425scalar must only be modified in-place while an aio operation is pending on
… …
1220 1427
1221It calls the C<msync> function of your OS, if available, with the memory 1428It calls the C<msync> function of your OS, if available, with the memory
1222area starting at C<$offset> in the string and ending C<$length> bytes 1429area starting at C<$offset> in the string and ending C<$length> bytes
1223later. If C<$length> is negative, counts from the end, and if C<$length> 1430later. If C<$length> is negative, counts from the end, and if C<$length>
1224is C<undef>, then it goes till the end of the string. The flags can be 1431is C<undef>, then it goes till the end of the string. The flags can be
1225a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1432either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1226C<IO::AIO::MS_SYNC>. 1433C<IO::AIO::MS_INVALIDATE>.
1227 1434
1228=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1435=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1229 1436
1230This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1437This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1231scalars. 1438scalars.
1232 1439
1233It touches (reads or writes) all memory pages in the specified 1440It touches (reads or writes) all memory pages in the specified
1234range inside the scalar. All caveats and parameters are the same 1441range inside the scalar. All caveats and parameters are the same
1235as for C<aio_msync>, above, except for flags, which must be either 1442as for C<aio_msync>, above, except for flags, which must be either
1236C<0> (which reads all pages and ensures they are instantiated) or 1443C<0> (which reads all pages and ensures they are instantiated) or
1237C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1444C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1238writing an octet from it, which dirties the page). 1445writing an octet from it, which dirties the page).
1239 1446
1240=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1447=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1241 1448
1242This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1449This is a rather advanced IO::AIO call, which works best on mmap(2)ed
… …
1261 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1468 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1262 aio_mlock $data; # mlock in background 1469 aio_mlock $data; # mlock in background
1263 1470
1264=item aio_mlockall $flags, $callback->($status) 1471=item aio_mlockall $flags, $callback->($status)
1265 1472
1266Calls the C<mlockall> function with the given C<$flags> (a combination of 1473Calls the C<mlockall> function with the given C<$flags> (a
1267C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1474combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1475C<IO::AIO::MCL_ONFAULT>).
1268 1476
1269On systems that do not implement C<mlockall>, this function returns C<-1> 1477On systems that do not implement C<mlockall>, this function returns C<-1>
1270and sets errno to C<ENOSYS>. 1478and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1479by the system result in a return value of C<-1> with errno being set to
1480C<EINVAL>.
1271 1481
1272Note that the corresponding C<munlockall> is synchronous and is 1482Note that the corresponding C<munlockall> is synchronous and is
1273documented under L<MISCELLANEOUS FUNCTIONS>. 1483documented under L<MISCELLANEOUS FUNCTIONS>.
1274 1484
1275Example: asynchronously lock all current and future pages into memory. 1485Example: asynchronously lock all current and future pages into memory.
1276 1486
1277 aio_mlockall IO::AIO::MCL_FUTURE; 1487 aio_mlockall IO::AIO::MCL_FUTURE;
1278 1488
1279=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) 1489=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1280 1490
1281Queries the extents of the given file (by calling the Linux FIEMAP ioctl, 1491Queries the extents of the given file (by calling the Linux C<FIEMAP>
1282see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the 1492ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1283C<ioctl> is not available on your OS, then this rquiest will fail with 1493the ioctl is not available on your OS, then this request will fail with
1284C<ENOSYS>. 1494C<ENOSYS>.
1285 1495
1286C<$start> is the starting offset to query extents for, C<$length> is the 1496C<$start> is the starting offset to query extents for, C<$length> is the
1287size of the range to query - if it is C<undef>, then the whole file will 1497size of the range to query - if it is C<undef>, then the whole file will
1288be queried. 1498be queried.
… …
1291C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also 1501C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1292exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query 1502exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1293the data portion. 1503the data portion.
1294 1504
1295C<$count> is the maximum number of extent records to return. If it is 1505C<$count> is the maximum number of extent records to return. If it is
1296C<undef>, then IO::AIO queries all extents of the file. As a very special 1506C<undef>, then IO::AIO queries all extents of the range. As a very special
1297case, if it is C<0>, then the callback receives the number of extents 1507case, if it is C<0>, then the callback receives the number of extents
1298instead of the extents themselves. 1508instead of the extents themselves (which is unreliable, see below).
1299 1509
1300If an error occurs, the callback receives no arguments. The special 1510If an error occurs, the callback receives no arguments. The special
1301C<errno> value C<IO::AIO::EBADR> is available to test for flag errors. 1511C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1302 1512
1303Otherwise, the callback receives an array reference with extent 1513Otherwise, the callback receives an array reference with extent
… …
1305following members: 1515following members:
1306 1516
1307 [$logical, $physical, $length, $flags] 1517 [$logical, $physical, $length, $flags]
1308 1518
1309Flags is any combination of the following flag values (typically either C<0> 1519Flags is any combination of the following flag values (typically either C<0>
1310or C<IO::AIO::FIEMAP_EXTENT_LAST>): 1520or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1311 1521
1312C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>, 1522C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1313C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>, 1523C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1314C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1524C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1315C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1525C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1316C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1526C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1317C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1527C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1318 1528
1529At the time of this writing (Linux 3.2), this request is unreliable unless
1530C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1531it to return all extents of a range for files with a large number of
1532extents. The code (only) works around all these issues if C<$count> is
1533C<undef>.
1534
1319=item aio_group $callback->(...) 1535=item aio_group $callback->(...)
1320 1536
1321This is a very special aio request: Instead of doing something, it is a 1537This is a very special aio request: Instead of doing something, it is a
1322container for other aio requests, which is useful if you want to bundle 1538container for other aio requests, which is useful if you want to bundle
1323many requests into a single, composite, request with a definite callback 1539many requests into a single, composite, request with a definite callback
… …
1406 aio_stat [$etcdir, "passwd"], sub { 1622 aio_stat [$etcdir, "passwd"], sub {
1407 # yay 1623 # yay
1408 }; 1624 };
1409 }; 1625 };
1410 1626
1411That C<aio_wd> is a request and not a normal function shows that creating 1627The fact that C<aio_wd> is a request and not a normal function shows that
1412an IO::AIO::WD object is itself a potentially blocking operation, which is 1628creating an IO::AIO::WD object is itself a potentially blocking operation,
1413why it is done asynchronously. 1629which is why it is done asynchronously.
1414 1630
1415To stat the directory obtained with C<aio_wd> above, one could write 1631To stat the directory obtained with C<aio_wd> above, one could write
1416either of the following three request calls: 1632either of the following three request calls:
1417 1633
1418 aio_lstat "/etc" , sub { ... # pathname as normal string 1634 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1435There are some caveats: when directories get renamed (or deleted), the 1651There are some caveats: when directories get renamed (or deleted), the
1436pathname string doesn't change, so will point to the new directory (or 1652pathname string doesn't change, so will point to the new directory (or
1437nowhere at all), while the directory fd, if available on the system, 1653nowhere at all), while the directory fd, if available on the system,
1438will still point to the original directory. Most functions accepting a 1654will still point to the original directory. Most functions accepting a
1439pathname will use the directory fd on newer systems, and the string on 1655pathname will use the directory fd on newer systems, and the string on
1440older systems. Some functions (such as realpath) will always rely on the 1656older systems. Some functions (such as C<aio_realpath>) will always rely on
1441string form of the pathname. 1657the string form of the pathname.
1442 1658
1443So this fucntionality is mainly useful to get some protection against 1659So this functionality is mainly useful to get some protection against
1444C<chdir>, to easily get an absolute path out of a relative path for future 1660C<chdir>, to easily get an absolute path out of a relative path for future
1445reference, and to speed up doing many operations in the same directory 1661reference, and to speed up doing many operations in the same directory
1446(e.g. when stat'ing all files in a directory). 1662(e.g. when stat'ing all files in a directory).
1447 1663
1448The following functions implement this working directory abstraction: 1664The following functions implement this working directory abstraction:
… …
1461passing C<undef> as working directory component of a pathname fails the 1677passing C<undef> as working directory component of a pathname fails the
1462request with C<ENOENT>, there is often no need for error checking in the 1678request with C<ENOENT>, there is often no need for error checking in the
1463C<aio_wd> callback, as future requests using the value will fail in the 1679C<aio_wd> callback, as future requests using the value will fail in the
1464expected way. 1680expected way.
1465 1681
1466If this call isn't available because your OS lacks it or it couldn't be
1467detected, it will be emulated by calling C<fsync> instead.
1468
1469=item IO::AIO::CWD 1682=item IO::AIO::CWD
1470 1683
1471This is a compiletime constant (object) that represents the process 1684This is a compile time constant (object) that represents the process
1472current working directory. 1685current working directory.
1473 1686
1474Specifying this object as working directory object for a pathname is as 1687Specifying this object as working directory object for a pathname is as if
1475if the pathname would be specified directly, without a directory object, 1688the pathname would be specified directly, without a directory object. For
1476e.g., these calls are functionally identical: 1689example, these calls are functionally identical:
1477 1690
1478 aio_stat "somefile", sub { ... }; 1691 aio_stat "somefile", sub { ... };
1479 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1692 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1480 1693
1481=back 1694=back
1482 1695
1696To recover the path associated with an IO::AIO::WD object, you can use
1697C<aio_realpath>:
1698
1699 aio_realpath $wd, sub {
1700 warn "path is $_[0]\n";
1701 };
1702
1703Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1704sometimes, fall back to using an absolue path.
1483 1705
1484=head2 IO::AIO::REQ CLASS 1706=head2 IO::AIO::REQ CLASS
1485 1707
1486All non-aggregate C<aio_*> functions return an object of this class when 1708All non-aggregate C<aio_*> functions return an object of this class when
1487called in non-void context. 1709called in non-void context.
… …
1648The default value for the limit is C<0>, but note that setting a feeder 1870The default value for the limit is C<0>, but note that setting a feeder
1649automatically bumps it up to C<2>. 1871automatically bumps it up to C<2>.
1650 1872
1651=back 1873=back
1652 1874
1875
1653=head2 SUPPORT FUNCTIONS 1876=head2 SUPPORT FUNCTIONS
1654 1877
1655=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1878=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1656 1879
1657=over 4 1880=over 4
… …
1665 1888
1666See C<poll_cb> for an example. 1889See C<poll_cb> for an example.
1667 1890
1668=item IO::AIO::poll_cb 1891=item IO::AIO::poll_cb
1669 1892
1670Process some outstanding events on the result pipe. You have to call 1893Process some requests that have reached the result phase (i.e. they have
1894been executed but the results are not yet reported). You have to call
1895this "regularly" to finish outstanding requests.
1896
1671this regularly. Returns C<0> if all events could be processed (or there 1897Returns C<0> if all events could be processed (or there were no
1672were no events to process), or C<-1> if it returned earlier for whatever 1898events to process), or C<-1> if it returned earlier for whatever
1673reason. Returns immediately when no events are outstanding. The amount of 1899reason. Returns immediately when no events are outstanding. The amount
1674events processed depends on the settings of C<IO::AIO::max_poll_req> and 1900of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1675C<IO::AIO::max_poll_time>. 1901C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1676 1902
1677If not all requests were processed for whatever reason, the filehandle 1903If not all requests were processed for whatever reason, the poll file
1678will still be ready when C<poll_cb> returns, so normally you don't have to 1904descriptor will still be ready when C<poll_cb> returns, so normally you
1679do anything special to have it called later. 1905don't have to do anything special to have it called later.
1680 1906
1681Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1907Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1682ready, it can be beneficial to call this function from loops which submit 1908ready, it can be beneficial to call this function from loops which submit
1683a lot of requests, to make sure the results get processed when they become 1909a lot of requests, to make sure the results get processed when they become
1684available and not just when the loop is finished and the event loop takes 1910available and not just when the loop is finished and the event loop takes
… …
1693 poll => 'r', async => 1, 1919 poll => 'r', async => 1,
1694 cb => \&IO::AIO::poll_cb); 1920 cb => \&IO::AIO::poll_cb);
1695 1921
1696=item IO::AIO::poll_wait 1922=item IO::AIO::poll_wait
1697 1923
1698If there are any outstanding requests and none of them in the result 1924Wait until either at least one request is in the result phase or no
1699phase, wait till the result filehandle becomes ready for reading (simply 1925requests are outstanding anymore.
1700does a C<select> on the filehandle. This is useful if you want to 1926
1701synchronously wait for some requests to finish). 1927This is useful if you want to synchronously wait for some requests to
1928become ready, without actually handling them.
1702 1929
1703See C<nreqs> for an example. 1930See C<nreqs> for an example.
1704 1931
1705=item IO::AIO::poll 1932=item IO::AIO::poll
1706 1933
… …
1717 1944
1718Strictly equivalent to: 1945Strictly equivalent to:
1719 1946
1720 IO::AIO::poll_wait, IO::AIO::poll_cb 1947 IO::AIO::poll_wait, IO::AIO::poll_cb
1721 while IO::AIO::nreqs; 1948 while IO::AIO::nreqs;
1949
1950This function can be useful at program aborts, to make sure outstanding
1951I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1952this function on normal exits), or when you are merely using C<IO::AIO>
1953for its more advanced functions, rather than for async I/O, e.g.:
1954
1955 my ($dirs, $nondirs);
1956 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1957 IO::AIO::flush;
1958 # $dirs, $nondirs are now set
1722 1959
1723=item IO::AIO::max_poll_reqs $nreqs 1960=item IO::AIO::max_poll_reqs $nreqs
1724 1961
1725=item IO::AIO::max_poll_time $seconds 1962=item IO::AIO::max_poll_time $seconds
1726 1963
… …
1753 poll => 'r', nice => 1, 1990 poll => 'r', nice => 1,
1754 cb => &IO::AIO::poll_cb); 1991 cb => &IO::AIO::poll_cb);
1755 1992
1756=back 1993=back
1757 1994
1995
1758=head3 CONTROLLING THE NUMBER OF THREADS 1996=head3 CONTROLLING THE NUMBER OF THREADS
1759 1997
1760=over 1998=over
1761 1999
1762=item IO::AIO::min_parallel $nthreads 2000=item IO::AIO::min_parallel $nthreads
… …
1823longer exceeded. 2061longer exceeded.
1824 2062
1825In other words, this setting does not enforce a queue limit, but can be 2063In other words, this setting does not enforce a queue limit, but can be
1826used to make poll functions block if the limit is exceeded. 2064used to make poll functions block if the limit is exceeded.
1827 2065
1828This is a very bad function to use in interactive programs because it 2066This is a bad function to use in interactive programs because it blocks,
1829blocks, and a bad way to reduce concurrency because it is inexact: Better 2067and a bad way to reduce concurrency because it is inexact. If you need to
2068issue many requests without being able to call a poll function on demand,
1830use an C<aio_group> together with a feed callback. 2069it is better to use an C<aio_group> together with a feed callback.
1831 2070
1832It's main use is in scripts without an event loop - when you want to stat 2071Its main use is in scripts without an event loop - when you want to stat a
1833a lot of files, you can write somehting like this: 2072lot of files, you can write something like this:
1834 2073
1835 IO::AIO::max_outstanding 32; 2074 IO::AIO::max_outstanding 32;
1836 2075
1837 for my $path (...) { 2076 for my $path (...) {
1838 aio_stat $path , ...; 2077 aio_stat $path , ...;
1839 IO::AIO::poll_cb; 2078 IO::AIO::poll_cb;
1840 } 2079 }
1841 2080
1842 IO::AIO::flush; 2081 IO::AIO::flush;
1843 2082
1844The call to C<poll_cb> inside the loop will normally return instantly, but 2083The call to C<poll_cb> inside the loop will normally return instantly,
1845as soon as more thna C<32> reqeusts are in-flight, it will block until 2084allowing the loop to progress, but as soon as more than C<32> requests
1846some requests have been handled. This keeps the loop from pushing a large 2085are in-flight, it will block until some requests have been handled. This
1847number of C<aio_stat> requests onto the queue. 2086keeps the loop from pushing a large number of C<aio_stat> requests onto
2087the queue (which, with many paths to stat, can use up a lot of memory).
1848 2088
1849The default value for C<max_outstanding> is very large, so there is no 2089The default value for C<max_outstanding> is very large, so there is no
1850practical limit on the number of outstanding requests. 2090practical limit on the number of outstanding requests.
1851 2091
1852=back 2092=back
1853 2093
2094
1854=head3 STATISTICAL INFORMATION 2095=head3 STATISTICAL INFORMATION
1855 2096
1856=over 2097=over
1857 2098
1858=item IO::AIO::nreqs 2099=item IO::AIO::nreqs
… …
1875Returns the number of requests currently in the pending state (executed, 2116Returns the number of requests currently in the pending state (executed,
1876but not yet processed by poll_cb). 2117but not yet processed by poll_cb).
1877 2118
1878=back 2119=back
1879 2120
2121
2122=head3 SUBSECOND STAT TIME ACCESS
2123
2124Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2125generally find access/modification and change times with subsecond time
2126accuracy of the system supports it, but perl's built-in functions only
2127return the integer part.
2128
2129The following functions return the timestamps of the most recent
2130stat with subsecond precision on most systems and work both after
2131C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2132value is only meaningful after a successful C<stat>/C<lstat> call, or
2133during/after a successful C<aio_stat>/C<aio_lstat> callback.
2134
2135This is similar to the L<Time::HiRes> C<stat> functions, but can return
2136full resolution without rounding and work with standard perl C<stat>,
2137alleviating the need to call the special C<Time::HiRes> functions, which
2138do not act like their perl counterparts.
2139
2140On operating systems or file systems where subsecond time resolution is
2141not supported or could not be detected, a fractional part of C<0> is
2142returned, so it is always safe to call these functions.
2143
2144=over 4
2145
2146=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2147
2148Return the access, modication, change or birth time, respectively,
2149including fractional part. Due to the limited precision of floating point,
2150the accuracy on most platforms is only a bit better than milliseconds
2151for times around now - see the I<nsec> function family, below, for full
2152accuracy.
2153
2154File birth time is only available when the OS and perl support it (on
2155FreeBSD and NetBSD at the time of this writing, although support is
2156adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
2157it). On systems where it isn't available, C<0> is currently returned, but
2158this might change to C<undef> in a future version.
2159
2160=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2161
2162Returns access, modification, change and birth time all in one go, and
2163maybe more times in the future version.
2164
2165=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2166
2167Return the fractional access, modifcation, change or birth time, in nanoseconds,
2168as an integer in the range C<0> to C<999999999>.
2169
2170Note that no accessors are provided for access, modification and
2171change times - you need to get those from C<stat _> if required (C<int
2172IO::AIO::st_atime> and so on will I<not> generally give you the correct
2173value).
2174
2175=item $seconds = IO::AIO::st_btimesec
2176
2177The (integral) seconds part of the file birth time, if available.
2178
2179=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2180
2181Like the functions above, but returns all four times in one go (and maybe
2182more in future versions).
2183
2184=item $counter = IO::AIO::st_gen
2185
2186Returns the generation counter (in practice this is just a random number)
2187of the file. This is only available on platforms which have this member in
2188their C<struct stat> (most BSDs at the time of this writing) and generally
2189only to the root usert. If unsupported, C<0> is returned, but this might
2190change to C<undef> in a future version.
2191
2192=back
2193
2194Example: print the high resolution modification time of F</etc>, using
2195C<stat>, and C<IO::AIO::aio_stat>.
2196
2197 if (stat "/etc") {
2198 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2199 }
2200
2201 IO::AIO::aio_stat "/etc", sub {
2202 $_[0]
2203 and return;
2204
2205 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2206 };
2207
2208 IO::AIO::flush;
2209
2210Output of the awbove on my system, showing reduced and full accuracy:
2211
2212 stat(/etc) mtime: 1534043702.020808
2213 aio_stat(/etc) mtime: 1534043702.020807792
2214
2215
1880=head3 MISCELLANEOUS FUNCTIONS 2216=head3 MISCELLANEOUS FUNCTIONS
1881 2217
1882IO::AIO implements some functions that might be useful, but are not 2218IO::AIO implements some functions that are useful when you want to use
1883asynchronous. 2219some "Advanced I/O" function not available to in Perl, without going the
2220"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2221counterpart.
1884 2222
1885=over 4 2223=over 4
2224
2225=item $numfd = IO::AIO::get_fdlimit
2226
2227Tries to find the current file descriptor limit and returns it, or
2228C<undef> and sets C<$!> in case of an error. The limit is one larger than
2229the highest valid file descriptor number.
2230
2231=item IO::AIO::min_fdlimit [$numfd]
2232
2233Try to increase the current file descriptor limit(s) to at least C<$numfd>
2234by changing the soft or hard file descriptor resource limit. If C<$numfd>
2235is missing, it will try to set a very high limit, although this is not
2236recommended when you know the actual minimum that you require.
2237
2238If the limit cannot be raised enough, the function makes a best-effort
2239attempt to increase the limit as much as possible, using various
2240tricks, while still failing. You can query the resulting limit using
2241C<IO::AIO::get_fdlimit>.
2242
2243If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2244true.
1886 2245
1887=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2246=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1888 2247
1889Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2248Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1890but is blocking (this makes most sense if you know the input data is 2249but is blocking (this makes most sense if you know the input data is
… …
1907=item IO::AIO::madvise $scalar, $offset, $len, $advice 2266=item IO::AIO::madvise $scalar, $offset, $len, $advice
1908 2267
1909Simply calls the C<posix_madvise> function (see its 2268Simply calls the C<posix_madvise> function (see its
1910manpage for details). The following advice constants are 2269manpage for details). The following advice constants are
1911available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2270available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1912C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2271C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2272C<IO::AIO::MADV_DONTNEED>.
2273
2274If C<$offset> is negative, counts from the end. If C<$length> is negative,
2275the remaining length of the C<$scalar> is used. If possible, C<$length>
2276will be reduced to fit into the C<$scalar>.
1913 2277
1914On systems that do not implement C<posix_madvise>, this function returns 2278On systems that do not implement C<posix_madvise>, this function returns
1915ENOSYS, otherwise the return value of C<posix_madvise>. 2279ENOSYS, otherwise the return value of C<posix_madvise>.
1916 2280
1917=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2281=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
1919Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2283Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1920$scalar (see its manpage for details). The following protect 2284$scalar (see its manpage for details). The following protect
1921constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2285constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1922C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2286C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1923 2287
2288If C<$offset> is negative, counts from the end. If C<$length> is negative,
2289the remaining length of the C<$scalar> is used. If possible, C<$length>
2290will be reduced to fit into the C<$scalar>.
2291
1924On systems that do not implement C<mprotect>, this function returns 2292On systems that do not implement C<mprotect>, this function returns
1925ENOSYS, otherwise the return value of C<mprotect>. 2293ENOSYS, otherwise the return value of C<mprotect>.
1926 2294
1927=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2295=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1928 2296
1929Memory-maps a file (or anonymous memory range) and attaches it to the 2297Memory-maps a file (or anonymous memory range) and attaches it to the
1930given C<$scalar>, which will act like a string scalar. Returns true on 2298given C<$scalar>, which will act like a string scalar. Returns true on
1931success, and false otherwise. 2299success, and false otherwise.
1932 2300
2301The scalar must exist, but its contents do not matter - this means you
2302cannot use a nonexistant array or hash element. When in doubt, C<undef>
2303the scalar first.
2304
1933The only operations allowed on the scalar are C<substr>/C<vec> that don't 2305The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1934change the string length, and most read-only operations such as copying it 2306which don't change the string length, and most read-only operations such
1935or searching it with regexes and so on. 2307as copying it or searching it with regexes and so on.
1936 2308
1937Anything else is unsafe and will, at best, result in memory leaks. 2309Anything else is unsafe and will, at best, result in memory leaks.
1938 2310
1939The memory map associated with the C<$scalar> is automatically removed 2311The memory map associated with the C<$scalar> is automatically removed
1940when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2312when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1941C<IO::AIO::munmap> functions are called. 2313or C<IO::AIO::munmap> functions are called on it.
1942 2314
1943This calls the C<mmap>(2) function internally. See your system's manual 2315This calls the C<mmap>(2) function internally. See your system's manual
1944page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2316page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1945 2317
1946The C<$length> must be larger than zero and smaller than the actual 2318The C<$length> must be larger than zero and smaller than the actual
1947filesize. 2319filesize.
1948 2320
1949C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2321C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1950C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2322C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1951 2323
1952C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2324C<$flags> can be a combination of
1953C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2325C<IO::AIO::MAP_SHARED> or
1954not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2326C<IO::AIO::MAP_PRIVATE>,
2327or a number of system-specific flags (when not available, the are C<0>):
1955(which is set to C<MAP_ANON> if your system only provides this 2328C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1956constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2329C<IO::AIO::MAP_LOCKED>,
1957C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2330C<IO::AIO::MAP_NORESERVE>,
2331C<IO::AIO::MAP_POPULATE>,
1958C<IO::AIO::MAP_NONBLOCK> 2332C<IO::AIO::MAP_NONBLOCK>,
2333C<IO::AIO::MAP_FIXED>,
2334C<IO::AIO::MAP_GROWSDOWN>,
2335C<IO::AIO::MAP_32BIT>,
2336C<IO::AIO::MAP_HUGETLB>,
2337C<IO::AIO::MAP_STACK>,
2338C<IO::AIO::MAP_FIXED_NOREPLACE>,
2339C<IO::AIO::MAP_SHARED_VALIDATE>,
2340C<IO::AIO::MAP_SYNC> or
2341C<IO::AIO::MAP_UNINITIALIZED>.
1959 2342
1960If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2343If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1961 2344
1962C<$offset> is the offset from the start of the file - it generally must be 2345C<$offset> is the offset from the start of the file - it generally must be
1963a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2346a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
1977 2360
1978=item IO::AIO::munmap $scalar 2361=item IO::AIO::munmap $scalar
1979 2362
1980Removes a previous mmap and undefines the C<$scalar>. 2363Removes a previous mmap and undefines the C<$scalar>.
1981 2364
2365=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2366
2367Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2368been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2369C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2370
2371Returns true if successful, and false otherwise. If the underlying mmapped
2372region has changed address, then the true value has the numerical value
2373C<1>, otherwise it has the numerical value C<0>:
2374
2375 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2376 or die "mremap: $!";
2377
2378 if ($success*1) {
2379 warn "scalar has chanegd address in memory\n";
2380 }
2381
2382C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2383implemented, but not supported and might go away in a future version.
2384
2385On systems where this call is not supported or is not emulated, this call
2386returns falls and sets C<$!> to C<ENOSYS>.
2387
2388=item IO::AIO::mlockall $flags
2389
2390Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
2391but is blocking.
2392
1982=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2393=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1983 2394
1984Calls the C<munlock> function, undoing the effects of a previous 2395Calls the C<munlock> function, undoing the effects of a previous
1985C<aio_mlock> call (see its description for details). 2396C<aio_mlock> call (see its description for details).
1986 2397
… …
1988 2399
1989Calls the C<munlockall> function. 2400Calls the C<munlockall> function.
1990 2401
1991On systems that do not implement C<munlockall>, this function returns 2402On systems that do not implement C<munlockall>, this function returns
1992ENOSYS, otherwise the return value of C<munlockall>. 2403ENOSYS, otherwise the return value of C<munlockall>.
2404
2405=item $fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
2406
2407Uses the GNU/Linux C<accept4(2)> syscall, if available, to accept a socket
2408and return the new file handle on success, or sets C<$!> and returns
2409C<undef> on error.
2410
2411The remote name of the new socket will be stored in C<$sockaddr>, which
2412will be extended to allow for at least C<$sockaddr_maxlen> octets. If the
2413socket name does not fit into C<$sockaddr_maxlen> octets, this is signaled
2414by returning a longer string in C<$sockaddr>, which might or might not be
2415truncated.
2416
2417To accept name-less sockets, use C<undef> for C<$sockaddr> and C<0> for
2418C<$sockaddr_maxlen>.
2419
2420The main reasons to use this syscall rather than portable C<accept(2)>
2421are that you can specify C<SOCK_NONBLOCK> and/or C<SOCK_CLOEXEC>
2422flags and you can accept name-less sockets by specifying C<0> for
2423C<$sockaddr_maxlen>, which is sadly not possible with perl's interface to
2424C<accept>.
1993 2425
1994=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags 2426=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1995 2427
1996Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or 2428Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
1997C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they 2429C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
… …
2006 2438
2007See the C<splice(2)> manpage for details. 2439See the C<splice(2)> manpage for details.
2008 2440
2009=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2441=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2010 2442
2011Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2443Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2012description for C<IO::AIO::splice> above for details. 2444description for C<IO::AIO::splice> above for details.
2445
2446=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2447
2448Attempts to query or change the pipe buffer size. Obviously works only
2449on pipes, and currently works only on GNU/Linux systems, and fails with
2450C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2451size on other systems, drop me a note.
2452
2453=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2454
2455This is a direct interface to the Linux L<pipe2(2)> system call. If
2456C<$flags> is missing or C<0>, then this should be the same as a call to
2457perl's built-in C<pipe> function and create a new pipe, and works on
2458systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2459(..., 4096, O_BINARY)>.
2460
2461If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2462the given flags (Linux 2.6.27, glibc 2.9).
2463
2464On success, the read and write file handles are returned.
2465
2466On error, nothing will be returned. If the pipe2 syscall is missing and
2467C<$flags> is non-zero, fails with C<ENOSYS>.
2468
2469Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2470time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2471C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2472
2473Example: create a pipe race-free w.r.t. threads and fork:
2474
2475 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2476 or die "pipe2: $!\n";
2477
2478=item $fh = IO::AIO::memfd_create $pathname[, $flags]
2479
2480This is a direct interface to the Linux L<memfd_create(2)> system
2481call. The (unhelpful) default for C<$flags> is C<0>, but your default
2482should be C<IO::AIO::MFD_CLOEXEC>.
2483
2484On success, the new memfd filehandle is returned, otherwise returns
2485C<undef>. If the memfd_create syscall is missing, fails with C<ENOSYS>.
2486
2487Please refer to L<memfd_create(2)> for more info on this call.
2488
2489The following C<$flags> values are available: C<IO::AIO::MFD_CLOEXEC>,
2490C<IO::AIO::MFD_ALLOW_SEALING> and C<IO::AIO::MFD_HUGETLB>.
2491
2492Example: create a new memfd.
2493
2494 my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
2495 or die "memfd_create: $!\n";
2496
2497=item $fh = IO::AIO::pidfd_open $pid[, $flags]
2498
2499This is an interface to the Linux L<pidfd_open(2)> system call. The
2500default for C<$flags> is C<0>.
2501
2502On success, a new pidfd filehandle is returned (that is already set to
2503close-on-exec), otherwise returns C<undef>. If the syscall is missing,
2504fails with C<ENOSYS>.
2505
2506Example: open pid 6341 as pidfd.
2507
2508 my $fh = IO::AIO::pidfd_open 6341
2509 or die "pidfd_open: $!\n";
2510
2511=item $status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[, $flags]]
2512
2513This is an interface to the Linux L<pidfd_send_signal> system call. The
2514default for C<$siginfo> is C<undef> and the default for C<$flags> is C<0>.
2515
2516Returns the system call status. If the syscall is missing, fails with
2517C<ENOSYS>.
2518
2519When specified, C<$siginfo> must be a reference to a hash with one or more
2520of the following members:
2521
2522=over
2523
2524=item code - the C<si_code> member
2525
2526=item pid - the C<si_pid> member
2527
2528=item uid - the C<si_uid> member
2529
2530=item value_int - the C<si_value.sival_int> member
2531
2532=item value_ptr - the C<si_value.sival_ptr> member, specified as an integer
2533
2534=back
2535
2536Example: send a SIGKILL to the specified process.
2537
2538 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, undef
2539 and die "pidfd_send_signal: $!\n";
2540
2541Example: send a SIGKILL to the specified process with extra data.
2542
2543 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, { code => -1, value_int => 7 }
2544 and die "pidfd_send_signal: $!\n";
2545
2546=item $fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
2547
2548This is an interface to the Linux L<pidfd_getfd> system call. The default
2549for C<$flags> is C<0>.
2550
2551On success, returns a dup'ed copy of the target file descriptor (specified
2552as an integer) returned (that is already set to close-on-exec), otherwise
2553returns C<undef>. If the syscall is missing, fails with C<ENOSYS>.
2554
2555Example: get a copy of standard error of another process and print soemthing to it.
2556
2557 my $errfh = IO::AIO::pidfd_getfd $pidfh, 2
2558 or die "pidfd_getfd: $!\n";
2559 print $errfh "stderr\n";
2560
2561=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2562
2563This is a direct interface to the Linux L<eventfd(2)> system call. The
2564(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2565
2566On success, the new eventfd filehandle is returned, otherwise returns
2567C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2568
2569Please refer to L<eventfd(2)> for more info on this call.
2570
2571The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2572C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2573
2574Example: create a new eventfd filehandle:
2575
2576 $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
2577 or die "eventfd: $!\n";
2578
2579=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2580
2581This is a direct interface to the Linux L<timerfd_create(2)> system
2582call. The (unhelpful) default for C<$flags> is C<0>, but your default
2583should be C<IO::AIO::TFD_CLOEXEC>.
2584
2585On success, the new timerfd filehandle is returned, otherwise returns
2586C<undef>. If the timerfd_create syscall is missing, fails with C<ENOSYS>.
2587
2588Please refer to L<timerfd_create(2)> for more info on this call.
2589
2590The following C<$clockid> values are
2591available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2592C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2593C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2594C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2595
2596The following C<$flags> values are available (Linux
25972.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2598
2599Example: create a new timerfd and set it to one-second repeated alarms,
2600then wait for two alarms:
2601
2602 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2603 or die "timerfd_create: $!\n";
2604
2605 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2606 or die "timerfd_settime: $!\n";
2607
2608 for (1..2) {
2609 8 == sysread $fh, my $buf, 8
2610 or die "timerfd read failure\n";
2611
2612 printf "number of expirations (likely 1): %d\n",
2613 unpack "Q", $buf;
2614 }
2615
2616=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2617
2618This is a direct interface to the Linux L<timerfd_settime(2)> system
2619call. Please refer to its manpage for more info on this call.
2620
2621The new itimerspec is specified using two (possibly fractional) second
2622values, C<$new_interval> and C<$new_value>).
2623
2624On success, the current interval and value are returned (as per
2625C<timerfd_gettime>). On failure, the empty list is returned.
2626
2627The following C<$flags> values are
2628available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2629C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2630
2631See C<IO::AIO::timerfd_create> for a full example.
2632
2633=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2634
2635This is a direct interface to the Linux L<timerfd_gettime(2)> system
2636call. Please refer to its manpage for more info on this call.
2637
2638On success, returns the current values of interval and value for the given
2639timerfd (as potentially fractional second values). On failure, the empty
2640list is returned.
2013 2641
2014=back 2642=back
2015 2643
2016=cut 2644=cut
2017 2645
… …
2083the process will result in undefined behaviour. Calling it at any time 2711the process will result in undefined behaviour. Calling it at any time
2084will also result in any undefined (by POSIX) behaviour. 2712will also result in any undefined (by POSIX) behaviour.
2085 2713
2086=back 2714=back
2087 2715
2716=head2 LINUX-SPECIFIC CALLS
2717
2718When a call is documented as "linux-specific" then this means it
2719originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2720availability and compatibility of such calls regardless of the platform
2721it is compiled on, so platforms such as FreeBSD which often implement
2722these calls will work. When in doubt, call them and see if they fail wth
2723C<ENOSYS>.
2724
2088=head2 MEMORY USAGE 2725=head2 MEMORY USAGE
2089 2726
2090Per-request usage: 2727Per-request usage:
2091 2728
2092Each aio request uses - depending on your architecture - around 100-200 2729Each aio request uses - depending on your architecture - around 100-200
… …
2104temporary buffers, and each thread requires a stack and other data 2741temporary buffers, and each thread requires a stack and other data
2105structures (usually around 16k-128k, depending on the OS). 2742structures (usually around 16k-128k, depending on the OS).
2106 2743
2107=head1 KNOWN BUGS 2744=head1 KNOWN BUGS
2108 2745
2109Known bugs will be fixed in the next release. 2746Known bugs will be fixed in the next release :)
2747
2748=head1 KNOWN ISSUES
2749
2750Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2751or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2752non-created hash slots or other scalars I didn't think of. It's best to
2753avoid such and either use scalar variables or making sure that the scalar
2754exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2755
2756I am not sure anything can be done about this, so this is considered a
2757known issue, rather than a bug.
2110 2758
2111=head1 SEE ALSO 2759=head1 SEE ALSO
2112 2760
2113L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2761L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2114more natural syntax. 2762more natural syntax and L<IO::FDPass> for file descriptor passing.
2115 2763
2116=head1 AUTHOR 2764=head1 AUTHOR
2117 2765
2118 Marc Lehmann <schmorp@schmorp.de> 2766 Marc Lehmann <schmorp@schmorp.de>
2119 http://home.schmorp.de/ 2767 http://home.schmorp.de/

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