#!/usr/bin/env perl
# Copyright 2009 The Go Authors. All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.
# This program reads a file containing function prototypes
# (like syscall_darwin.go) and generates system call bodies.
# The prototypes are marked by lines beginning with "//sys"
# and read like func declarations if //sys is replaced by func, but:
# * The parameter lists must give a name for each argument.
# This includes return parameters.
# * The parameter lists must give a type for each argument:
# the (x, y, z int) shorthand is not allowed.
# * If the return parameter is an error number, it must be named errno.
# A line beginning with //sysnb is like //sys, except that the
# goroutine will not be suspended during the execution of the system
# call. This must only be used for system calls which can never
# block, as otherwise the system call could cause all goroutines to
# hang.
use strict;
my $cmdline = "mksyscall.pl " . join(' ', @ARGV);
my $errors = 0;
my $_32bit = "";
my $plan9 = 0;
my $openbsd = 0;
my $netbsd = 0;
my $dragonfly = 0;
my $arm = 0; # 64-bit value should use (even, odd)-pair
my $tags = ""; # build tags
if($ARGV[0] eq "-b32") {
$_32bit = "big-endian";
shift;
} elsif($ARGV[0] eq "-l32") {
$_32bit = "little-endian";
shift;
}
if($ARGV[0] eq "-plan9") {
$plan9 = 1;
shift;
}
if($ARGV[0] eq "-openbsd") {
$openbsd = 1;
shift;
}
if($ARGV[0] eq "-netbsd") {
$netbsd = 1;
shift;
}
if($ARGV[0] eq "-dragonfly") {
$dragonfly = 1;
shift;
}
if($ARGV[0] eq "-arm") {
$arm = 1;
shift;
}
if($ARGV[0] eq "-tags") {
shift;
$tags = $ARGV[0];
shift;
}
if($ARGV[0] =~ /^-/) {
print STDERR "usage: mksyscall.pl [-b32 | -l32] [-tags x,y] [file ...]\n";
exit 1;
}
# Check that we are using the new build system if we should
if($ENV{'GOOS'} eq "linux" && $ENV{'GOARCH'} ne "sparc64") {
if($ENV{'GOLANG_SYS_BUILD'} ne "docker") {
print STDERR "In the new build system, mksyscall should not be called directly.\n";
print STDERR "See README.md\n";
exit 1;
}
}
sub parseparamlist($) {
my ($list) = @_;
$list =~ s/^\s*//;
$list =~ s/\s*$//;
if($list eq "") {
return ();
}
return split(/\s*,\s*/, $list);
}
sub parseparam($) {
my ($p) = @_;
if($p !~ /^(\S*) (\S*)$/) {
print STDERR "$ARGV:$.: malformed parameter: $p\n";
$errors = 1;
return ("xx", "int");
}
return ($1, $2);
}
my $text = "";
while(<>) {
chomp;
s/\s+/ /g;
s/^\s+//;
s/\s+$//;
my $nonblock = /^\/\/sysnb /;
next if !/^\/\/sys / && !$nonblock;
# Line must be of the form
# func Open(path string, mode int, perm int) (fd int, errno error)
# Split into name, in params, out params.
if(!/^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*((?i)SYS_[A-Z0-9_]+))?$/) {
print STDERR "$ARGV:$.: malformed //sys declaration\n";
$errors = 1;
next;
}
my ($func, $in, $out, $sysname) = ($2, $3, $4, $5);
# Split argument lists on comma.
my @in = parseparamlist($in);
my @out = parseparamlist($out);
# Try in vain to keep people from editing this file.
# The theory is that they jump into the middle of the file
# without reading the header.
$text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n";
# Go function header.
my $out_decl = @out ? sprintf(" (%s)", join(', ', @out)) : "";
$text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out_decl;
# Check if err return available
my $errvar = "";
foreach my $p (@out) {
my ($name, $type) = parseparam($p);
if($type eq "error") {
$errvar = $name;
last;
}
}
# Prepare arguments to Syscall.
my @args = ();
my $n = 0;
foreach my $p (@in) {
my ($name, $type) = parseparam($p);
if($type =~ /^\*/) {
push @args, "uintptr(unsafe.Pointer($name))";
} elsif($type eq "string" && $errvar ne "") {
$text .= "\tvar _p$n *byte\n";
$text .= "\t_p$n, $errvar = BytePtrFromString($name)\n";
$text .= "\tif $errvar != nil {\n\t\treturn\n\t}\n";
push @args, "uintptr(unsafe.Pointer(_p$n))";
$n++;
} elsif($type eq "string") {
print STDERR "$ARGV:$.: $func uses string arguments, but has no error return\n";
$text .= "\tvar _p$n *byte\n";
$text .= "\t_p$n, _ = BytePtrFromString($name)\n";
push @args, "uintptr(unsafe.Pointer(_p$n))";
$n++;
} elsif($type =~ /^\[\](.*)/) {
# Convert slice into pointer, length.
# Have to be careful not to take address of &a[0] if len == 0:
# pass dummy pointer in that case.
# Used to pass nil, but some OSes or simulators reject write(fd, nil, 0).
$text .= "\tvar _p$n unsafe.Pointer\n";
$text .= "\tif len($name) > 0 {\n\t\t_p$n = unsafe.Pointer(\&${name}[0])\n\t}";
$text .= " else {\n\t\t_p$n = unsafe.Pointer(&_zero)\n\t}";
$text .= "\n";
push @args, "uintptr(_p$n)", "uintptr(len($name))";
$n++;
} elsif($type eq "int64" && ($openbsd || $netbsd)) {
push @args, "0";
if($_32bit eq "big-endian") {
push @args, "uintptr($name>>32)", "uintptr($name)";
} elsif($_32bit eq "little-endian") {
push @args, "uintptr($name)", "uintptr($name>>32)";
} else {
push @args, "uintptr($name)";
}
} elsif($type eq "int64" && $dragonfly) {
if ($func !~ /^extp(read|write)/i) {
push @args, "0";
}
if($_32bit eq "big-endian") {
push @args, "uintptr($name>>32)", "uintptr($name)";
} elsif($_32bit eq "little-endian") {
push @args, "uintptr($name)", "uintptr($name>>32)";
} else {
push @args, "uintptr($name)";
}
} elsif($type eq "int64" && $_32bit ne "") {
if(@args % 2 && $arm) {
# arm abi specifies 64-bit argument uses
# (even, odd) pair
push @args, "0"
}
if($_32bit eq "big-endian") {
push @args, "uintptr($name>>32)", "uintptr($name)";
} else {
push @args, "uintptr($name)", "uintptr($name>>32)";
}
} else {
push @args, "uintptr($name)";
}
}
# Determine which form to use; pad args with zeros.
my $asm = "Syscall";
if ($nonblock) {
if ($errvar eq "" && $ENV{'GOOS'} eq "linux") {
$asm = "RawSyscallNoError";
} else {
$asm = "RawSyscall";
}
} else {
if ($errvar eq "" && $ENV{'GOOS'} eq "linux") {
$asm = "SyscallNoError";
}
}
if(@args <= 3) {
while(@args < 3) {
push @args, "0";
}
} elsif(@args <= 6) {
$asm .= "6";
while(@args < 6) {
push @args, "0";
}
} elsif(@args <= 9) {
$asm .= "9";
while(@args < 9) {
push @args, "0";
}
} else {
print STDERR "$ARGV:$.: too many arguments to system call\n";
}
# System call number.
if($sysname eq "") {
$sysname = "SYS_$func";
$sysname =~ s/([a-z])([A-Z])/${1}_$2/g; # turn FooBar into Foo_Bar
$sysname =~ y/a-z/A-Z/;
}
# Actual call.
my $args = join(', ', @args);
my $call = "$asm($sysname, $args)";
# Assign return values.
my $body = "";
my @ret = ("_", "_", "_");
my $do_errno = 0;
for(my $i=0; $i<@out; $i++) {
my $p = $out[$i];
my ($name, $type) = parseparam($p);
my $reg = "";
if($name eq "err" && !$plan9) {
$reg = "e1";
$ret[2] = $reg;
$do_errno = 1;
} elsif($name eq "err" && $plan9) {
$ret[0] = "r0";
$ret[2] = "e1";
next;
} else {
$reg = sprintf("r%d", $i);
$ret[$i] = $reg;
}
if($type eq "bool") {
$reg = "$reg != 0";
}
if($type eq "int64" && $_32bit ne "") {
# 64-bit number in r1:r0 or r0:r1.
if($i+2 > @out) {
print STDERR "$ARGV:$.: not enough registers for int64 return\n";
}
if($_32bit eq "big-endian") {
$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i, $i+1);
} else {
$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i+1, $i);
}
$ret[$i] = sprintf("r%d", $i);
$ret[$i+1] = sprintf("r%d", $i+1);
}
if($reg ne "e1" || $plan9) {
$body .= "\t$name = $type($reg)\n";
}
}
if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") {
$text .= "\t$call\n";
} else {
if ($errvar eq "" && $ENV{'GOOS'} eq "linux") {
# raw syscall without error on Linux, see golang.org/issue/22924
$text .= "\t$ret[0], $ret[1] := $call\n";
} else {
$text .= "\t$ret[0], $ret[1], $ret[2] := $call\n";
}
}
$text .= $body;
if ($plan9 && $ret[2] eq "e1") {
$text .= "\tif int32(r0) == -1 {\n";
$text .= "\t\terr = e1\n";
$text .= "\t}\n";
} elsif ($do_errno) {
$text .= "\tif e1 != 0 {\n";
$text .= "\t\terr = errnoErr(e1)\n";
$text .= "\t}\n";
}
$text .= "\treturn\n";
$text .= "}\n\n";
}
chomp $text;
chomp $text;
if($errors) {
exit 1;
}
print <<EOF;
// $cmdline
// Code generated by the command above; see README.md. DO NOT EDIT.
// +build $tags
package unix
import (
"syscall"
"unsafe"
)
var _ syscall.Errno
$text
EOF
exit 0;