1 # This is a fork of the (for now) unmaintained Sys::Syscall 0.25,
2 # specifically the Debian libsys-syscall-perl 0.25-6 version to
3 # fix upstream regressions in 0.25.
5 # See devel/syscall-list in the public-inbox source tree for maintenance
6 # <https://80x24.org/public-inbox.git>, and machines from the GCC Farm:
7 # <https://cfarm.tetaneutral.net/>
9 # This license differs from the rest of public-inbox
11 # This module is Copyright (c) 2005 Six Apart, Ltd.
12 # Copyright (C) all contributors <meta@public-inbox.org>
14 # All rights reserved.
16 # You may distribute under the terms of either the GNU General Public
17 # License or the Artistic License, as specified in the Perl README file.
18 package PublicInbox::Syscall;
20 use parent qw(Exporter);
21 use POSIX qw(ENOENT ENOSYS EINVAL O_NONBLOCK);
22 use Socket qw(SOL_SOCKET SCM_RIGHTS);
24 our %SIGNUM = (WINCH => 28); # most Linux, {Free,Net,Open}BSD, *Darwin
26 # $VERSION = '0.25'; # Sys::Syscall version
27 our @EXPORT_OK = qw(epoll_ctl epoll_create epoll_wait
28 EPOLLIN EPOLLOUT EPOLLET
29 EPOLL_CTL_ADD EPOLL_CTL_DEL EPOLL_CTL_MOD
30 EPOLLONESHOT EPOLLEXCLUSIVE
31 signalfd rename_noreplace %SIGNUM);
32 our %EXPORT_TAGS = (epoll => [qw(epoll_ctl epoll_create epoll_wait
34 EPOLL_CTL_ADD EPOLL_CTL_DEL EPOLL_CTL_MOD
35 EPOLLONESHOT EPOLLEXCLUSIVE)],
44 EPOLLEXCLUSIVE => (1 << 28),
45 EPOLLONESHOT => (1 << 30),
50 SIZEOF_int => $Config{intsize},
51 SIZEOF_size_t => $Config{sizesize},
56 TMPL_size_t => SIZEOF_size_t == 8 ? 'Q' : 'L',
57 BYTES_4_hole => SIZEOF_size_t == 8 ? 'L' : '',
58 # cmsg_len, cmsg_level, cmsg_type
59 SIZEOF_cmsghdr => SIZEOF_int * 2 + SIZEOF_size_t,
62 my @BYTES_4_hole = BYTES_4_hole ? (0) : ();
72 my ($SYS_sendmsg, $SYS_recvmsg);
73 my $SYS_fstatfs; # don't need fstatfs64, just statfs.f_type
74 my ($FS_IOC_GETFLAGS, $FS_IOC_SETFLAGS);
75 my $SFD_CLOEXEC = 02000000; # Perl does not expose O_CLOEXEC
76 our $no_deprecated = 0;
79 my (undef, undef, $release, undef, $machine) = POSIX::uname();
80 my ($maj, $min) = ($release =~ /\A([0-9]+)\.([0-9]+)/);
81 $SYS_renameat2 = 0 if "$maj.$min" < 3.15;
82 # whether the machine requires 64-bit numbers to be on 8-byte
86 if ($Config{ptrsize} == 4) {
87 # if we're running on an x86_64 kernel, but a 32-bit process,
88 # we need to use the x32 or i386 syscall numbers.
89 if ($machine eq 'x86_64') {
90 $machine = $Config{cppsymbols} =~ /\b__ILP32__=1\b/ ? 'x32' : 'i386'
91 } elsif ($machine eq 'mips64') { # similarly for mips64 vs mips
96 if ($machine =~ m/^i[3456]86$/) {
97 $SYS_epoll_create = 254;
99 $SYS_epoll_wait = 256;
100 $SYS_signalfd4 = 327;
101 $SYS_renameat2 //= 353;
105 $FS_IOC_GETFLAGS = 0x80046601;
106 $FS_IOC_SETFLAGS = 0x40046602;
107 } elsif ($machine eq "x86_64") {
108 $SYS_epoll_create = 213;
109 $SYS_epoll_ctl = 233;
110 $SYS_epoll_wait = 232;
111 $SYS_signalfd4 = 289;
112 $SYS_renameat2 //= 316;
116 $FS_IOC_GETFLAGS = 0x80086601;
117 $FS_IOC_SETFLAGS = 0x40086602;
118 } elsif ($machine eq 'x32') {
119 $SYS_epoll_create = 1073742037;
120 $SYS_epoll_ctl = 1073742057;
121 $SYS_epoll_wait = 1073742056;
122 $SYS_signalfd4 = 1073742113;
123 $SYS_renameat2 //= 0x40000000 + 316;
125 $SYS_sendmsg = 0x40000206;
126 $SYS_recvmsg = 0x40000207;
127 $FS_IOC_GETFLAGS = 0x80046601;
128 $FS_IOC_SETFLAGS = 0x40046602;
129 } elsif ($machine eq 'sparc64') {
130 $SYS_epoll_create = 193;
131 $SYS_epoll_ctl = 194;
132 $SYS_epoll_wait = 195;
134 $SYS_signalfd4 = 317;
135 $SYS_renameat2 //= 345;
136 $SFD_CLOEXEC = 020000000;
140 $FS_IOC_GETFLAGS = 0x40086601;
141 $FS_IOC_SETFLAGS = 0x80086602;
142 } elsif ($machine =~ m/^parisc/) {
143 $SYS_epoll_create = 224;
144 $SYS_epoll_ctl = 225;
145 $SYS_epoll_wait = 226;
147 $SYS_signalfd4 = 309;
149 } elsif ($machine =~ m/^ppc64/) {
150 $SYS_epoll_create = 236;
151 $SYS_epoll_ctl = 237;
152 $SYS_epoll_wait = 238;
154 $SYS_signalfd4 = 313;
155 $SYS_renameat2 //= 357;
159 $FS_IOC_GETFLAGS = 0x40086601;
160 $FS_IOC_SETFLAGS = 0x80086602;
161 } elsif ($machine eq "ppc") {
162 $SYS_epoll_create = 236;
163 $SYS_epoll_ctl = 237;
164 $SYS_epoll_wait = 238;
166 $SYS_signalfd4 = 313;
167 $SYS_renameat2 //= 357;
169 $FS_IOC_GETFLAGS = 0x40086601;
170 $FS_IOC_SETFLAGS = 0x80086602;
171 } elsif ($machine =~ m/^s390/) { # untested, no machine on cfarm
172 $SYS_epoll_create = 249;
173 $SYS_epoll_ctl = 250;
174 $SYS_epoll_wait = 251;
176 $SYS_signalfd4 = 322;
177 $SYS_renameat2 //= 347;
181 } elsif ($machine eq 'ia64') { # untested, no machine on cfarm
182 $SYS_epoll_create = 1243;
183 $SYS_epoll_ctl = 1244;
184 $SYS_epoll_wait = 1245;
186 $SYS_signalfd4 = 289;
187 } elsif ($machine eq "alpha") { # untested, no machine on cfarm
188 # natural alignment, ints are 32-bits
189 $SYS_epoll_create = 407;
190 $SYS_epoll_ctl = 408;
191 $SYS_epoll_wait = 409;
193 $SYS_signalfd4 = 484;
194 $SFD_CLOEXEC = 010000000;
195 } elsif ($machine =~ /\A(?:loong)?aarch64\z/ || $machine eq 'riscv64') {
196 $SYS_epoll_create = 20; # (sys_epoll_create1)
198 $SYS_epoll_wait = 22; # (sys_epoll_pwait)
202 $SYS_renameat2 //= 276;
206 $FS_IOC_GETFLAGS = 0x80086601;
207 $FS_IOC_SETFLAGS = 0x40086602;
208 } elsif ($machine =~ m/arm(v\d+)?.*l/) { # ARM OABI (untested on cfarm)
209 $SYS_epoll_create = 250;
210 $SYS_epoll_ctl = 251;
211 $SYS_epoll_wait = 252;
213 $SYS_signalfd4 = 355;
214 $SYS_renameat2 //= 382;
218 } elsif ($machine =~ m/^mips64/) { # cfarm only has 32-bit userspace
219 $SYS_epoll_create = 5207;
220 $SYS_epoll_ctl = 5208;
221 $SYS_epoll_wait = 5209;
223 $SYS_signalfd4 = 5283;
224 $SYS_renameat2 //= 5311;
228 $FS_IOC_GETFLAGS = 0x40046601;
229 $FS_IOC_SETFLAGS = 0x80046602;
230 } elsif ($machine =~ m/^mips/) { # 32-bit, tested on mips64 cfarm machine
231 $SYS_epoll_create = 4248;
232 $SYS_epoll_ctl = 4249;
233 $SYS_epoll_wait = 4250;
235 $SYS_signalfd4 = 4324;
236 $SYS_renameat2 //= 4351;
240 $FS_IOC_GETFLAGS = 0x40046601;
241 $FS_IOC_SETFLAGS = 0x80046602;
245 machine=$machine ptrsize=$Config{ptrsize} has no syscall definitions
246 git clone https://80x24.org/public-inbox.git and
247 Send the output of ./devel/syscall-list to meta\@public-inbox.org
251 *epoll_wait = \&epoll_wait_mod8;
252 *epoll_ctl = \&epoll_ctl_mod8;
254 *epoll_wait = \&epoll_wait_mod4;
255 *epoll_ctl = \&epoll_ctl_mod4;
258 # use Inline::C for *BSD-only or general POSIX stuff.
259 # Linux guarantees stable syscall numbering, BSDs only offer a stable libc
260 # use devel/syscall-list on Linux to detect new syscall numbers
262 ############################################################################
264 ############################################################################
267 syscall($SYS_epoll_create, $no_deprecated ? 0 : 100);
271 # ARGS: (epfd, op, fd, events_mask)
273 syscall($SYS_epoll_ctl, $_[0]+0, $_[1]+0, $_[2]+0, pack("LLL", $_[3], $_[2], 0));
276 syscall($SYS_epoll_ctl, $_[0]+0, $_[1]+0, $_[2]+0, pack("LLLL", $_[3], 0, $_[2], 0));
280 # ARGS: (epfd, maxevents, timeout (milliseconds), arrayref)
281 # arrayref: values modified to be [$fd, $event]
282 our $epoll_wait_events = '';
283 our $epoll_wait_size = 0;
284 sub epoll_wait_mod4 {
285 my ($epfd, $maxevents, $timeout_msec, $events) = @_;
286 # resize our static buffer if maxevents bigger than we've ever done
287 if ($maxevents > $epoll_wait_size) {
288 $epoll_wait_size = $maxevents;
289 vec($epoll_wait_events, $maxevents * 12 * 8 - 1, 1) = 0;
292 my $ct = syscall($SYS_epoll_wait, $epfd, $epoll_wait_events,
293 $maxevents, $timeout_msec);
295 # 12-byte struct epoll_event
296 # 4 bytes uint32_t events mask (skipped, useless to us)
297 # 8 bytes: epoll_data_t union (first 4 bytes are the fd)
298 # So we skip the first 4 bytes and take the middle 4:
299 $events->[$_] = unpack('L', substr($epoll_wait_events,
304 sub epoll_wait_mod8 {
305 my ($epfd, $maxevents, $timeout_msec, $events) = @_;
307 # resize our static buffer if maxevents bigger than we've ever done
308 if ($maxevents > $epoll_wait_size) {
309 $epoll_wait_size = $maxevents;
310 vec($epoll_wait_events, $maxevents * 16 * 8 - 1, 1) = 0;
313 my $ct = syscall($SYS_epoll_wait, $epfd, $epoll_wait_events,
314 $maxevents, $timeout_msec,
315 $no_deprecated ? undef : ());
317 # 16-byte struct epoll_event
318 # 4 bytes uint32_t events mask (skipped, useless to us)
319 # 4 bytes padding (skipped, useless)
320 # 8 bytes epoll_data_t union (first 4 bytes are the fd)
321 # So skip the first 8 bytes, take 4, and ignore the last 4:
322 $events->[$_] = unpack('L', substr($epoll_wait_events,
328 my ($signos, $nonblock) = @_;
329 if ($SYS_signalfd4) {
330 my $set = POSIX::SigSet->new(@$signos);
331 syscall($SYS_signalfd4, -1, "$$set",
332 # $Config{sig_count} is NSIG, so this is NSIG/8:
333 int($Config{sig_count}/8),
334 # SFD_NONBLOCK == O_NONBLOCK for every architecture
335 ($nonblock ? O_NONBLOCK : 0) |$SFD_CLOEXEC);
342 sub _rename_noreplace_racy ($$) {
343 my ($old, $new) = @_;
344 if (link($old, $new)) {
345 warn "unlink $old: $!\n" if !unlink($old) && $! != ENOENT;
352 # TODO: support FD args?
353 sub rename_noreplace ($$) {
354 my ($old, $new) = @_;
355 if ($SYS_renameat2) { # RENAME_NOREPLACE = 1, AT_FDCWD = -100
356 my $ret = syscall($SYS_renameat2, -100, $old, -100, $new, 1);
358 1; # like rename() perlop
359 } elsif ($! == ENOSYS || $! == EINVAL) {
360 undef $SYS_renameat2;
361 _rename_noreplace_racy($old, $new);
366 _rename_noreplace_racy($old, $new);
370 sub nodatacow_fh ($) {
372 my $buf = "\0" x 120;
373 syscall($SYS_fstatfs // return, fileno($fh), $buf) == 0 or
374 return warn("fstatfs: $!\n");
375 my $f_type = unpack('l!', $buf); # statfs.f_type is a signed word
376 return if $f_type != 0x9123683E; # BTRFS_SUPER_MAGIC
379 return warn('FS_IOC_GETFLAGS undefined for platform');
380 ioctl($fh, $FS_IOC_GETFLAGS, $buf) //
381 return warn("FS_IOC_GETFLAGS: $!\n");
382 my $attr = unpack('l!', $buf);
383 return if ($attr & 0x00800000); # FS_NOCOW_FL;
384 ioctl($fh, $FS_IOC_SETFLAGS, pack('l', $attr | 0x00800000)) //
385 warn("FS_IOC_SETFLAGS: $!\n");
389 if (open my $fh, '<', $_[0]) { nodatacow_fh($fh) }
392 sub CMSG_ALIGN ($) { ($_[0] + SIZEOF_size_t - 1) & ~(SIZEOF_size_t - 1) }
393 use constant CMSG_ALIGN_SIZEOF_cmsghdr => CMSG_ALIGN(SIZEOF_cmsghdr);
394 sub CMSG_SPACE ($) { CMSG_ALIGN($_[0]) + CMSG_ALIGN_SIZEOF_cmsghdr }
395 sub CMSG_LEN ($) { CMSG_ALIGN_SIZEOF_cmsghdr + $_[0] }
396 use constant msg_controllen => CMSG_SPACE(10 * SIZEOF_int) + 16; # 10 FDs
398 if (defined($SYS_sendmsg) && defined($SYS_recvmsg)) {
400 *send_cmd4 = sub ($$$$) {
401 my ($sock, $fds, undef, $flags) = @_;
402 my $iov = pack('P'.TMPL_size_t,
403 $_[2] // NUL, length($_[2] // NUL) || 1);
404 my $cmsghdr = pack(TMPL_size_t . # cmsg_len
405 'LL' . # cmsg_level, cmsg_type,
406 ('i' x scalar(@$fds)),
407 CMSG_LEN(scalar(@$fds) * SIZEOF_int), # cmsg_len
408 SOL_SOCKET, SCM_RIGHTS, # cmsg_{level,type}
410 my $mh = pack('PL' . # msg_name, msg_namelen (socklen_t (U32))
411 BYTES_4_hole . # 4-byte padding on 64-bit
412 'P'.TMPL_size_t . # msg_iov, msg_iovlen,
413 'P'.TMPL_size_t . # msg_control, msg_controllen,
415 NUL, 0, # msg_name, msg_namelen (unused)
417 $iov, 1, # msg_iov, msg_iovlen
418 $cmsghdr, # msg_control
419 CMSG_SPACE(scalar(@$fds) * SIZEOF_int), # msg_controllen
424 $sent = syscall($SYS_sendmsg, fileno($sock), $mh, $flags);
425 } while ($sent < 0 &&
426 ($!{ENOBUFS} || $!{ENOMEM} || $!{ETOOMANYREFS}) &&
428 warn "sleeping on sendmsg: $! (#$try)\n" &&
429 select(undef, undef, undef, 0.1) == 0);
430 $sent >= 0 ? $sent : undef;
433 *recv_cmd4 = sub ($$$) {
434 my ($sock, undef, $len) = @_;
435 vec($_[1] //= '', ($len + 1) * 8, 1) = 0;
436 my $cmsghdr = "\0" x msg_controllen; # 10 * sizeof(int)
437 my $iov = pack('P'.TMPL_size_t, $_[1], $len);
438 my $mh = pack('PL' . # msg_name, msg_namelen (socklen_t (U32))
439 BYTES_4_hole . # 4-byte padding on 64-bit
440 'P'.TMPL_size_t . # msg_iov, msg_iovlen,
441 'P'.TMPL_size_t . # msg_control, msg_controllen,
443 NUL, 0, # msg_name, msg_namelen (unused)
445 $iov, 1, # msg_iov, msg_iovlen
446 $cmsghdr, # msg_control
449 my $r = syscall($SYS_recvmsg, fileno($sock), $mh, 0);
450 return (undef) if $r < 0; # $! set
451 substr($_[1], $r, length($_[1]), '');
454 my ($len, $lvl, $type, @fds) = unpack(TMPL_size_t . # cmsg_len
455 'LLi*', # cmsg_level, cmsg_type, @fds
457 if ($lvl == SOL_SOCKET && $type == SCM_RIGHTS) {
458 $len -= CMSG_ALIGN_SIZEOF_cmsghdr;
459 @ret = @fds[0..(($len / SIZEOF_int) - 1)];
470 This is free software. IT COMES WITHOUT WARRANTY OF ANY KIND.
474 Brad Fitzpatrick <brad@danga.com>