# This license differs from the rest of public-inbox
#
# This module is Copyright (c) 2005 Six Apart, Ltd.
-# Copyright (C) 2019-2020 all contributors <meta@public-inbox.org>
+# Copyright (C) 2019-2021 all contributors <meta@public-inbox.org>
#
# All rights reserved.
#
# License or the Artistic License, as specified in the Perl README file.
package PublicInbox::Syscall;
use strict;
+use v5.10.1;
use parent qw(Exporter);
-use POSIX qw(ENOSYS O_NONBLOCK);
+use POSIX qw(ENOENT EEXIST ENOSYS O_NONBLOCK);
use Config;
# $VERSION = '0.25'; # Sys::Syscall version
EPOLLIN EPOLLOUT EPOLLET
EPOLL_CTL_ADD EPOLL_CTL_DEL EPOLL_CTL_MOD
EPOLLONESHOT EPOLLEXCLUSIVE
- signalfd $SFD_NONBLOCK);
+ signalfd rename_noreplace);
our %EXPORT_TAGS = (epoll => [qw(epoll_ctl epoll_create epoll_wait
EPOLLIN EPOLLOUT
EPOLL_CTL_ADD EPOLL_CTL_DEL EPOLL_CTL_MOD
$clean->(); # don't trust modules before us
my $rv = eval { require 'syscall.ph'; 1 } || eval { require 'sys/syscall.ph'; 1 };
$clean->(); # don't require modules after us trust us
- return $rv;
+ $rv;
}
$SYS_epoll_ctl,
$SYS_epoll_wait,
$SYS_signalfd4,
+ $SYS_renameat2,
);
my $SFD_CLOEXEC = 02000000; # Perl does not expose O_CLOEXEC
-our $SFD_NONBLOCK = O_NONBLOCK;
our $no_deprecated = 0;
if ($^O eq "linux") {
- my $machine = (POSIX::uname())[-1];
+ my (undef, undef, $release, undef, $machine) = POSIX::uname();
+ my ($maj, $min) = ($release =~ /\A([0-9]+)\.([0-9]+)/);
+ $SYS_renameat2 = 0 if "$maj.$min" < 3.15;
# whether the machine requires 64-bit numbers to be on 8-byte
# boundaries.
my $u64_mod_8 = 0;
$SYS_epoll_ctl = 255;
$SYS_epoll_wait = 256;
$SYS_signalfd4 = 327;
+ $SYS_renameat2 //= 353;
} elsif ($machine eq "x86_64") {
$SYS_epoll_create = 213;
$SYS_epoll_ctl = 233;
$SYS_epoll_wait = 232;
$SYS_signalfd4 = 289;
+ $SYS_renameat2 //= 316;
} elsif ($machine eq 'x32') {
$SYS_epoll_create = 1073742037;
$SYS_epoll_ctl = 1073742057;
$SYS_epoll_wait = 1073742056;
$SYS_signalfd4 = 1073742113;
+ $SYS_renameat2 //= 0x40000000 + 316;
} elsif ($machine eq 'sparc64') {
$SYS_epoll_create = 193;
$SYS_epoll_ctl = 194;
$SYS_epoll_wait = 195;
$u64_mod_8 = 1;
$SYS_signalfd4 = 317;
+ $SYS_renameat2 //= 345;
$SFD_CLOEXEC = 020000000;
} elsif ($machine =~ m/^parisc/) {
$SYS_epoll_create = 224;
$SYS_epoll_wait = 238;
$u64_mod_8 = 1;
$SYS_signalfd4 = 313;
+ $SYS_renameat2 //= 357;
} elsif ($machine eq "ppc") {
$SYS_epoll_create = 236;
$SYS_epoll_ctl = 237;
$SYS_epoll_wait = 238;
$u64_mod_8 = 1;
$SYS_signalfd4 = 313;
+ $SYS_renameat2 //= 357;
} elsif ($machine =~ m/^s390/) {
$SYS_epoll_create = 249;
$SYS_epoll_ctl = 250;
$SYS_epoll_wait = 251;
$u64_mod_8 = 1;
$SYS_signalfd4 = 322;
+ $SYS_renameat2 //= 347;
} elsif ($machine eq "ia64") {
$SYS_epoll_create = 1243;
$SYS_epoll_ctl = 1244;
$u64_mod_8 = 1;
$no_deprecated = 1;
$SYS_signalfd4 = 74;
+ $SYS_renameat2 //= 276;
} elsif ($machine =~ m/arm(v\d+)?.*l/) {
# ARM OABI
$SYS_epoll_create = 250;
$SYS_epoll_wait = 252;
$u64_mod_8 = 1;
$SYS_signalfd4 = 355;
+ $SYS_renameat2 //= 382;
} elsif ($machine =~ m/^mips64/) {
$SYS_epoll_create = 5207;
$SYS_epoll_ctl = 5208;
$SYS_epoll_wait = 5209;
$u64_mod_8 = 1;
$SYS_signalfd4 = 5283;
+ $SYS_renameat2 //= 5311;
} elsif ($machine =~ m/^mips/) {
$SYS_epoll_create = 4248;
$SYS_epoll_ctl = 4249;
$SYS_epoll_wait = 4250;
$u64_mod_8 = 1;
$SYS_signalfd4 = 4324;
+ $SYS_renameat2 //= 4351;
} else {
# as a last resort, try using the *.ph files which may not
# exist or may be wrong
*epoll_ctl = \&epoll_ctl_mod4;
}
}
-
-elsif ($^O eq "freebsd") {
- if ($ENV{FREEBSD_SENDFILE}) {
- # this is still buggy and in development
- }
-}
+# use Inline::C for *BSD-only or general POSIX stuff.
+# Linux guarantees stable syscall numbering, BSDs only offer a stable libc
+# use scripts/syscall-list on Linux to detect new syscall numbers
############################################################################
# epoll functions
############################################################################
-sub epoll_defined { return $SYS_epoll_create ? 1 : 0; }
+sub epoll_defined { $SYS_epoll_create ? 1 : 0; }
sub epoll_create {
- syscall($SYS_epoll_create, $no_deprecated ? 0 : ($_[0]||100)+0);
+ syscall($SYS_epoll_create, $no_deprecated ? 0 : 100);
}
# epoll_ctl wrapper
# epoll_wait wrapper
# ARGS: (epfd, maxevents, timeout (milliseconds), arrayref)
# arrayref: values modified to be [$fd, $event]
-our $epoll_wait_events;
+our $epoll_wait_events = '';
our $epoll_wait_size = 0;
sub epoll_wait_mod4 {
- # resize our static buffer if requested size is bigger than we've ever done
- if ($_[1] > $epoll_wait_size) {
- $epoll_wait_size = $_[1];
- $epoll_wait_events = "\0" x 12 x $epoll_wait_size;
- }
- my $ct = syscall($SYS_epoll_wait, $_[0]+0, $epoll_wait_events, $_[1]+0, $_[2]+0);
- for (0..$ct-1) {
- @{$_[3]->[$_]}[1,0] = unpack("LL", substr($epoll_wait_events, 12*$_, 8));
- }
- return $ct;
+ my ($epfd, $maxevents, $timeout_msec, $events) = @_;
+ # resize our static buffer if maxevents bigger than we've ever done
+ if ($maxevents > $epoll_wait_size) {
+ $epoll_wait_size = $maxevents;
+ vec($epoll_wait_events, $maxevents * 12 * 8 - 1, 1) = 0;
+ }
+ @$events = ();
+ my $ct = syscall($SYS_epoll_wait, $epfd, $epoll_wait_events,
+ $maxevents, $timeout_msec);
+ for (0..$ct - 1) {
+ # 12-byte struct epoll_event
+ # 4 bytes uint32_t events mask (skipped, useless to us)
+ # 8 bytes: epoll_data_t union (first 4 bytes are the fd)
+ # So we skip the first 4 bytes and take the middle 4:
+ $events->[$_] = unpack('L', substr($epoll_wait_events,
+ 12 * $_ + 4, 4));
+ }
}
sub epoll_wait_mod8 {
- # resize our static buffer if requested size is bigger than we've ever done
- if ($_[1] > $epoll_wait_size) {
- $epoll_wait_size = $_[1];
- $epoll_wait_events = "\0" x 16 x $epoll_wait_size;
- }
- my $ct;
- if ($no_deprecated) {
- $ct = syscall($SYS_epoll_wait, $_[0]+0, $epoll_wait_events, $_[1]+0, $_[2]+0, undef);
- } else {
- $ct = syscall($SYS_epoll_wait, $_[0]+0, $epoll_wait_events, $_[1]+0, $_[2]+0);
- }
- for (0..$ct-1) {
- # 16 byte epoll_event structs, with format:
- # 4 byte mask [idx 1]
- # 4 byte padding (we put it into idx 2, useless)
- # 8 byte data (first 4 bytes are fd, into idx 0)
- @{$_[3]->[$_]}[1,2,0] = unpack("LLL", substr($epoll_wait_events, 16*$_, 12));
- }
- return $ct;
+ my ($epfd, $maxevents, $timeout_msec, $events) = @_;
+
+ # resize our static buffer if maxevents bigger than we've ever done
+ if ($maxevents > $epoll_wait_size) {
+ $epoll_wait_size = $maxevents;
+ vec($epoll_wait_events, $maxevents * 16 * 8 - 1, 1) = 0;
+ }
+ @$events = ();
+ my $ct = syscall($SYS_epoll_wait, $epfd, $epoll_wait_events,
+ $maxevents, $timeout_msec,
+ $no_deprecated ? undef : ());
+ for (0..$ct - 1) {
+ # 16-byte struct epoll_event
+ # 4 bytes uint32_t events mask (skipped, useless to us)
+ # 4 bytes padding (skipped, useless)
+ # 8 bytes epoll_data_t union (first 4 bytes are the fd)
+ # So skip the first 8 bytes, take 4, and ignore the last 4:
+ $events->[$_] = unpack('L', substr($epoll_wait_events,
+ 16 * $_ + 8, 4));
+ }
}
-sub signalfd ($$$) {
- my ($fd, $signos, $flags) = @_;
+sub signalfd ($$) {
+ my ($signos, $nonblock) = @_;
if ($SYS_signalfd4) {
my $set = POSIX::SigSet->new(@$signos);
- syscall($SYS_signalfd4, $fd, "$$set",
+ syscall($SYS_signalfd4, -1, "$$set",
# $Config{sig_count} is NSIG, so this is NSIG/8:
int($Config{sig_count}/8),
- $flags|$SFD_CLOEXEC);
+ # SFD_NONBLOCK == O_NONBLOCK for every architecture
+ ($nonblock ? O_NONBLOCK : 0) |$SFD_CLOEXEC);
} else {
$! = ENOSYS;
undef;
}
}
+sub _rename_noreplace_racy ($$) {
+ my ($old, $new) = @_;
+ if (link($old, $new)) {
+ warn "unlink $old: $!\n" if !unlink($old) && $! != ENOENT;
+ 1
+ } else {
+ undef;
+ }
+}
+
+# TODO: support FD args?
+sub rename_noreplace ($$) {
+ my ($old, $new) = @_;
+ if ($SYS_renameat2) { # RENAME_NOREPLACE = 1, AT_FDCWD = -100
+ my $ret = syscall($SYS_renameat2, -100, $old, -100, $new, 1);
+ if ($ret == 0) {
+ 1; # like rename() perlop
+ } elsif ($! == ENOSYS) {
+ undef $SYS_renameat2;
+ _rename_noreplace_racy($old, $new);
+ } else {
+ undef
+ }
+ } else {
+ _rename_noreplace_racy($old, $new);
+ }
+}
+
1;
=head1 WARRANTY