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