--- /dev/null
+#!/usr/bin/perl
+# $OpenBSD: gen_syscall_emulator.pl,v 1.1 2023/09/03 01:43:09 afresh1 Exp $ #
+use v5.36;
+use autodie;
+
+# Copyright (c) 2023 Andrew Hewus Fresh <afresh1@openbsd.org>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+my $includes = '/usr/include';
+
+# Because perl uses a long for every syscall argument,
+# if we are building a syscall_emulator for use by perl,
+# taking that into account make things work more consistently
+# across different OpenBSD architectures.
+# Unfortunately there doesn't appear to be an easy way
+# to make everything work "the way it was".
+use constant PERL_LONG_ARGS => 1;
+
+# See also /usr/src/sys/kern/syscalls.master
+my %syscalls = parse_syscalls(
+ "$includes/sys/syscall.h",
+ "$includes/sys/syscallargs.h",
+)->%*;
+delete $syscalls{MAXSYSCALL}; # not an actual function
+
+# The ordered list of all the headers we need
+my @headers = qw<
+ sys/syscall.h
+ stdarg.h
+ errno.h
+
+ sys/socket.h
+ sys/event.h
+ sys/futex.h
+ sys/ioctl.h
+ sys/ktrace.h
+ sys/mman.h
+ sys/mount.h
+ sys/msg.h
+ sys/poll.h
+ sys/ptrace.h
+ sys/resource.h
+ sys/select.h
+ sys/sem.h
+ sys/shm.h
+ sys/stat.h
+ sys/sysctl.h
+ sys/time.h
+ sys/uio.h
+ sys/wait.h
+
+ dirent.h
+ fcntl.h
+ sched.h
+ signal.h
+ stdlib.h
+ stdio.h
+ syslog.h
+ tib.h
+ time.h
+ unistd.h
+>;
+
+foreach my $header (@headers) {
+ my $filename = "$includes/$header";
+ open my $fh, '<', $filename;
+ my $content = do { local $/; readline $fh };
+ close $fh;
+
+ foreach my $name (sort keys %syscalls) {
+ my $s = $syscalls{$name};
+ my $func_sig = find_func_sig($content, $name, $s);
+
+ if (ref $func_sig) {
+ die "Multiple defs for $name <$header> <$s->{header}>"
+ if $s->{header};
+ $s->{func} = $func_sig;
+ $s->{header} = $header;
+ } elsif ($func_sig) {
+ $s->{mismatched_sig} = "$func_sig <$header>";
+ }
+ }
+}
+
+say "/*\n * Generated from gen_syscall_emulator.pl\n */";
+say "#include <$_>" for @headers;
+print <<"EOL";
+#include "syscall_emulator.h"
+
+long
+syscall_emulator(int syscall, ...)
+{
+ long ret = 0;
+ va_list args;
+ va_start(args, syscall);
+
+ switch(syscall) {
+EOL
+
+foreach my $name (
+ sort { $syscalls{$a}{id} <=> $syscalls{$b}{id} } keys %syscalls
+ ) {
+ my %s = %{ $syscalls{$name} };
+
+ # Some syscalls we can't emulate, so we comment those out.
+ $s{skip} //= "Indirect syscalls not supported"
+ if !$s{argtypes} && ($s{args}[-1] || '') eq '...';
+ $s{skip} //= "Mismatched func: $s{mismatched_sig}"
+ if $s{mismatched_sig} and not $s{func};
+ $s{skip} //= "No signature found in headers"
+ unless $s{header};
+
+ my $ret = $s{ret} eq 'void' ? '' : 'ret = ';
+ $ret .= '(long)' if $s{ret} eq 'void *';
+
+ my (@args, @defines);
+ my $argname = '';
+ if ($s{argtypes}) {
+ if (@{ $s{argtypes} } > 1) {
+ @defines = map {
+ my $t = $_->{type};
+ my $n = $_->{name};
+ $n = "_$n" if $n eq $name; # link :-/
+ push @args, $n;
+ PERL_LONG_ARGS
+ ? "$t $n = ($t)va_arg(args, long);"
+ : "$t $n = va_arg(args, $t);"
+ } @{ $s{argtypes} };
+ } else {
+ if (@{ $s{argtypes} }) {
+ $argname = " // " . join ', ',
+ map { $_->{name} }
+ @{ $s{argtypes} };
+ }
+ @args = map { "va_arg(args, $_->{type})" }
+ @{ $s{argtypes} };
+ }
+ } else {
+ @args = @{ $s{args} };
+
+ # If we didn't find args in syscallargs.h but have args
+ # we don't know how to write our function.
+ $s{skip} //= "Not found in sys/syscallargs.h"
+ if @args;
+ }
+
+ #my $header = $s{header} ? " <$s{header}>" : '';
+
+ my $indent = "\t";
+ say "$indent/* $s{skip}" if $s{skip};
+
+ $indent .= ' *' if $s{skip};
+ say "${indent} $s{signature} <sys/syscall.h>"
+ if $s{skip} && $s{skip} =~ /Mismatch/;
+
+ my $brace = @defines ? " {" : "";
+ say "${indent}case $s{define}:$brace"; # // $s{id}";
+ say "${indent}\t$_" for @defines;
+ #say "${indent}\t// $s{signature}$header";
+ say "${indent}\t$ret$name(" . join(', ', @args) . ");$argname";
+ say "${indent}\tbreak;";
+ say "${indent}}" if $brace;
+
+ say "\t */" if $s{skip};
+}
+
+print <<"EOL";
+ default:
+ ret = -1;
+ errno = ENOSYS;
+ }
+ va_end(args);
+
+ return ret;
+}
+EOL
+
+
+sub parse_syscalls($syscall, $args)
+{
+ my %s = parse_syscall_h($syscall)->%*;
+
+ my %a = parse_syscallargs_h($args)->%*;
+ $s{$_}{argtypes} = $a{$_} for grep { $a{$_} } keys %s;
+
+ return \%s;
+}
+
+sub parse_syscall_h($filename)
+{
+ my %s;
+ open my $fh, '<', $filename;
+ while (readline $fh) {
+ if (m{^/\*
+ \s+ syscall: \s+ "(?<name>[^"]+)"
+ \s+ ret: \s+ "(?<ret> [^"]+)"
+ \s+ args: \s+ (?<args>.*?)
+ \s* \*/
+ |
+ ^\#define \s+ (?<define>SYS_(?<name>\S+)) \s+ (?<id>\d+)
+ }x)
+ {
+ my $name = $+{name};
+ $s{$name}{$_} = $+{$_} for keys %+;
+ $s{$name}{args} = [ $+{args} =~ /"(.*?)"/g ]
+ if exists $+{args};
+ }
+ }
+ close $fh;
+
+ foreach my $name (keys %s) {
+ my %d = %{ $s{$name} };
+ next unless $d{ret}; # the MAXSYSCALL
+
+ my $ret = $d{ret};
+ my @args = @{ $d{args} || [] };
+ @args = 'void' unless @args;
+
+ if ($args[-1] ne '...') {
+ my @a;
+ for (@args) {
+ push @a, $_;
+ last if $_ eq '...';
+ }
+ @args = @a;
+ }
+
+ my $args = join ", ", @args;
+ $s{$name}{signature} = "$ret\t$name($args);" =~ s/\s+/ /gr;
+ #print " $s{$name}{signature}\n";
+ }
+
+ return \%s;
+}
+
+sub parse_syscallargs_h($filename)
+{
+ my %args;
+
+ open my $fh, '<', $filename;
+ while (readline $fh) {
+ if (my ($syscall) = /^struct \s+ sys_(\w+)_args \s+ \{/x) {
+ $args{$syscall} = [];
+ while (readline $fh) {
+ last if /^\s*\};\s*$/;
+ if (/syscallarg
+ \( (?<type> [^)]+ ) \)
+ \s+ (?<name> \w+ ) \s* ;
+ /x) {
+ push @{$args{$syscall}}, {%+};
+ }
+ }
+ }
+ }
+ close $fh;
+
+ return \%args;
+}
+
+sub find_func_sig($content, $name, $s)
+{
+ my $re = $s->{re} //= qr{^
+ (?<ret> \S+ (?: [^\S\n]+ \S+)? ) [^\S\n]* \n?
+ \b \Q$name\E \( (?<args> [^)]* ) \)
+ [^;]*;
+ }xms;
+
+ $content =~ /$re/ || return !!0;
+ my $ret = $+{ret};
+ my $args = $+{args};
+
+ for ($ret, $args) {
+ s/^\s+//;
+ s/\s+$//;
+ s/\s+/ /g;
+ }
+
+ # The actual functions may have this extra annotation
+ $args =~ s/\*\s*__restrict/*/g;
+
+ my %func_sig = ( ret => $ret, args => [ split /\s*,\s*/, $args ] );
+
+ return "$ret $name($args);" =~ s/\s+/ /gr
+ unless sigs_match($s, \%func_sig);
+
+ return \%func_sig;
+}
+
+# Tests whether two types are equivalent.
+# Sometimes there are two ways to represent the same thing
+# and it seems the functions and the syscalls
+# differ a fair amount.
+sub types_match($l, $r)
+{
+ state %m = (
+ caddr_t => 'char *',
+ idtype_t => 'int',
+ nfds_t => 'u_int',
+ __off_t => 'off_t',
+ pid_t => 'int',
+ __size_t => 'u_long',
+ size_t => 'u_long',
+ 'unsigned int' => 'u_int',
+ 'unsigned long' => 'u_long',
+ );
+
+ $l //= '__undef__';
+ $r //= '__undef__';
+
+ s/\b volatile \s+//x for $l, $r;
+ s/\b const \s+//x for $l, $r;
+ s/\s* \[\d*\] $/ \*/x for $l, $r;
+
+ my ($f, $s) = sort { length($a) <=> length($b) } $l, $r;
+ if (index($s, $f) == 0) {
+ $s =~ s/^\Q$f\E\s*//;
+ if ( $s && $s =~ /^\w+$/ ) {
+ #warn "prefix ['$f', '$s']\n";
+ s/\s*\Q$s\E$// for $l, $r;
+ }
+ }
+
+ $l = $m{$l} //= $l;
+ $r = $m{$r} //= $r;
+
+ return $l eq $r;
+}
+
+
+# Tests whether two function signatures match,
+# expected to be left from syscall.h, right from the appopriate header.
+sub sigs_match($l, $r)
+{
+ return !!0 unless types_match( $l->{ret}, $l->{ret} );
+
+ my @l_args = @{ $l->{args} || [] };
+ my @r_args = @{ $r->{args} || [] };
+
+ for (\@l_args, \@r_args) {
+ @{$_} = 'void' unless @{$_};
+ }
+
+ for my $i ( 0 .. $#l_args ) {
+ return !!0 unless types_match($l_args[$i], $r_args[$i]);
+ last if $l_args[$i] eq '...';
+ }
+
+ return !!1;
+}
--- /dev/null
+#!/usr/bin/perl
+# $OpenBSD: syscall_emulator.t,v 1.1 2023/09/03 01:43:09 afresh1 Exp $ #
+
+# Copyright (c) 2023 Andrew Hewus Fresh <afresh1@openbsd.org>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+BEGIN {
+ chdir 't' if -d 't';
+ require "./test.pl";
+ set_up_inc( qw(. ../lib lib ../dist/base/lib) );
+}
+
+use v5.36;
+
+use File::Temp;
+use POSIX qw< S_IRUSR S_IWUSR S_IRGRP S_IROTH O_CREAT O_WRONLY O_RDONLY >;
+
+use constant {
+ PROT_READ => 0x01,
+ MAP_PRIVATE => 0x0002,
+ MAP_FAILED => -1,
+};
+
+my $dir = File::Temp->newdir("syscall_emulator-XXXXXXXXX");
+{
+ local $ENV{PERL5LIB} = join ':', @INC;
+ open(my $fh, '-|', $^X, "../utils/h2ph", '-d', $dir,
+ "/usr/include/sys/syscall.h") or die "h2ph: $!";
+ note <$fh>;
+ close($fh) or die $! ? "h2ph: $!" : "h2ph: $?";
+ local @INC = ("$dir/usr/include", "$dir");
+ require 'sys/syscall.ph';
+}
+
+my $filename = "test.txt";
+my $file = "$dir/$filename";
+my $fd;
+my $out = "Hello World\n";
+my $in = "\0" x 32;
+my ($in_p, $in_v);
+my $sb = "\0" x 4096;
+my $st_mode;
+
+my $perms = S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH;
+
+plan tests => 17;
+
+ok(!
+ (($fd = syscall(SYS_open(), $file, O_CREAT|O_WRONLY, $perms)) < 0),
+ "Opened $filename for write/create"
+);
+ok(!
+ (syscall(SYS_write(), $fd, $out, length $out) <= 0),
+ "Wrote out to $filename"
+);
+ok(!
+ (syscall(SYS_close(), $fd) != 0),
+ "closed $filename"
+);
+
+
+ok(!
+ (syscall(SYS_stat(), $file, $sb) != 0),
+ "stat $filename"
+);
+
+# fortunately st_mode is the first unsigned long in stat struct
+$st_mode = unpack "L", $sb;
+
+ok( ($st_mode & 0777) == ($perms & 0777),
+ sprintf "new file %s has correct permissions (%o)",
+ $filename, $st_mode & 0777
+);
+
+ok(!
+ (($fd = syscall(SYS_open(), $file, O_RDONLY)) < 0),
+ "Opened $filename for read"
+);
+ok(!
+ (syscall(SYS_read(), $fd, $in, length $in) <= 0),
+ "read from $filename"
+);
+
+$in = unpack 'Z*', $in;
+
+ok( length($in) == length($out) && ($in eq $out),
+ "Read written content from $filename"
+);
+
+ok(!
+ (syscall(SYS_lseek(), $fd, 0, SEEK_SET) < 0),
+ "lseek on fd"
+);
+
+ok(!
+ (syscall(SYS_pread(), $fd, $in = "\0" x 32, 5, 3) < 0),
+ "pread on fd"
+);
+
+$in = unpack 'Z*', $in;
+
+ok( length($in) == 5 && ($in eq substr $out, 3, 5),
+ "Read written content from $filename ($in)"
+);
+
+ok(!
+ (syscall(SYS_lseek(), $fd, 0, SEEK_SET) < 0),
+ "lseek on fd"
+);
+
+ok(!
+ (syscall(SYS_lseek(), $fd, 0, SEEK_SET) < 0),
+ "lseek on fd"
+);
+
+ok(!
+ (($in_p = syscall(SYS_mmap(), undef, length($out), PROT_READ, MAP_PRIVATE,
+ $fd, 0)) == MAP_FAILED),
+ "mmap fd"
+);
+
+# From ingy's Pointer module
+$in_v = unpack "p*", pack "L!", $in_p;
+
+ok( length($in_v) == length($out) && ($in_v eq $out),
+ "Read written content from $filename"
+);
+
+ok(!
+ (syscall(SYS_munmap(), $in_p, length($out)) != 0),
+ "munmap fd"
+);
+
+ok(!
+ (syscall(SYS_close(), $fd) != 0),
+ "closed $filename"
+);
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