src/syscall/mksyscall_libc.pl - go - Git at Google

 #!/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_solaris.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 err.
 #	* If go func name needs to be different than its libc name,
 #	* or the function is not in libc, name could be specified
 #	* at the end, after "=" sign, like
 #	  //sys getsockopt(s int, level int, name int, val uintptr, vallen *_Socklen) (err error) = libsocket.getsockopt

 use strict;

 my $cmdline = "mksyscall_libc.pl " . join(' ', @ARGV);
 my $errors = 0;
 my $_32bit = "";
 my $tags = "";  # build tags
 my $newtags = ""; # new style build tags
 my $aix = 0;
 my $solaris = 0;

 binmode STDOUT;

 if($ARGV[0] eq "-b32") {
 	$_32bit = "big-endian";
 	shift;
 } elsif($ARGV[0] eq "-l32") {
 	$_32bit = "little-endian";
 	shift;
 }
 if($ARGV[0] eq "-aix") {
 	$aix = 1;
 	shift;
 }
 if($ARGV[0] eq "-solaris") {
 	$solaris = 1;
 	shift;
 }
 if($ARGV[0] eq "-tags") {
 	shift;
 	$tags = $ARGV[0];
 	shift;
 }


 if($ARGV[0] =~ /^-/) {
 	print STDERR "usage: mksyscall_libc.pl [-b32 | -l32] [-aix | -solaris] [-tags x,y] [file ...]\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 $package = "";
 my $text = "";
 my $dynimports = "";
 my $linknames = "";
 my @vars = ();
 while(<>) {
 	chomp;
 	s/\s+/ /g;
 	s/^\s+//;
 	s/\s+$//;
 	$package = $1 if !$package && /^package (\S+)$/;
 	my $nonblock = /^\/\/sysnb /;
 	next if !/^\/\/sys / && !$nonblock;

 	my $syscalldot = "";
 	$syscalldot = "syscall." if $package ne "syscall";

 	# Line must be of the form
 	#	func Open(path string, mode int, perm int) (fd int, err error)
 	# Split into name, in params, out params.
 	if(!/^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*(?:(\w*)\.)?(\w*))?$/) {
 		print STDERR "$ARGV:$.: malformed //sys declaration\n";
 		$errors = 1;
 		next;
 	}
 	my ($nb, $func, $in, $out, $modname, $sysname) = ($1, $2, $3, $4, $5, $6);

 	# 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";

 	# So file name.
 	if($aix) {
 		if($modname eq "") {
 			$modname = "libc.a/shr_64.o";
 		} else {
 			print STDERR "$func: only syscall using libc are available\n";
 			$errors = 1;
 			next;
 		}

 	}
 	if($solaris) {
 		if($modname eq "") {
 			$modname = "libc";
 		}
 		$modname .= ".so";

 	}

 	# System call name.
 	if($sysname eq "") {
 		$sysname = "$func";
 	}

 	# System call pointer variable name.
 	my $sysvarname = "libc_${sysname}";

 	my $strconvfunc = "BytePtrFromString";
 	my $strconvtype = "*byte";

 	$sysname =~ y/A-Z/a-z/; # All libc functions are lowercase.

 	# Runtime import of function to allow cross-platform builds.
 	$dynimports .= "//go:cgo_import_dynamic ${sysvarname} ${sysname} \"$modname\"\n";
 	# Link symbol to proc address variable.
 	$linknames .= "//go:linkname ${sysvarname} ${sysvarname}\n";
 	# Library proc address variable.
 	push @vars, $sysvarname;

 	# Go function header.
 	$out = join(', ', @out);
 	if($out ne "") {
 		$out = " ($out)";
 	}
 	if($text ne "") {
 		$text .= "\n"
 	}
 	$text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out;

 	# 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 $strconvtype\n";
 			$text .= "\t_p$n, $errvar = $strconvfunc($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 $strconvtype\n";
 			$text .= "\t_p$n, _ = $strconvfunc($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 nil in that case.
 			$text .= "\tvar _p$n *$1\n";
 			$text .= "\tif len($name) > 0 {\n\t\t_p$n = \&$name\[0]\n\t}\n";
 			push @args, "uintptr(unsafe.Pointer(_p$n))", "uintptr(len($name))";
 			$n++;
 		} elsif($type eq "int64" && $_32bit ne "") {
 			if($_32bit eq "big-endian") {
 				push @args, "uintptr($name >> 32)", "uintptr($name)";
 			} else {
 				push @args, "uintptr($name)", "uintptr($name >> 32)";
 			}
 		} elsif($type eq "bool") {
  			$text .= "\tvar _p$n uint32\n";
 			$text .= "\tif $name {\n\t\t_p$n = 1\n\t} else {\n\t\t_p$n = 0\n\t}\n";
 			push @args, "uintptr(_p$n)";
 			$n++;
 		} else {
 			push @args, "uintptr($name)";
 		}
 	}
 	my $nargs = @args;

 	my $asmfuncname="";
 	my $asmrawfuncname="";

 	if($aix){
 		$asmfuncname="syscall6";
 		$asmrawfuncname="rawSyscall6";
 	} else {
 		$asmfuncname="sysvicall6";
 		$asmrawfuncname="rawSysvicall6";
 	}

 	# Determine which form to use; pad args with zeros.
 	my $asm = "${syscalldot}${asmfuncname}";
 	if ($nonblock) {
 		$asm = "${syscalldot}${asmrawfuncname}";
 	}
 	if(@args <= 6) {
 		while(@args < 6) {
 			push @args, "0";
 		}
 	} else {
 		print STDERR "$ARGV:$.: too many arguments to system call\n";
 	}

 	# Actual call.
 	my $args = join(', ', @args);
 	my $call = "$asm(uintptr(unsafe.Pointer(&$sysvarname)), $nargs, $args)";

 	# Assign return values.
 	my $body = "";
 	my $failexpr = "";
 	my @ret = ("_", "_", "_");
 	my @pout= ();
 	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") {
 			$reg = "e1";
 			$ret[2] = $reg;
 			$do_errno = 1;
 		} 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") {
 			$body .= "\t$name = $type($reg)\n";
 		}
 	}
 	if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") {
 		$text .= "\t$call\n";
 	} else {
 		$text .= "\t$ret[0], $ret[1], $ret[2] := $call\n";
 	}
 	$text .= $body;

 	if ($do_errno) {
 		$text .= "\tif e1 != 0 {\n";
 		$text .= "\t\terr = errnoErr(e1)\n";
 		$text .= "\t}\n";
 	}
 	$text .= "\treturn\n";
 	$text .= "}\n";
 }

 if($errors) {
 	exit 1;
 }

 # TODO: this assumes tags are just simply comma separated. For now this is all the uses.
 $newtags = $tags =~ s/,/ && /r;

 print <<EOF;
 // $cmdline
 // Code generated by the command above; DO NOT EDIT.

 //go:build $newtags
 // +build $tags

 package $package

 import "unsafe"
 EOF

 print "import \"syscall\"\n" if $package ne "syscall";

 my $vardecls = "\t" . join(",\n\t", @vars);
 $vardecls .= " libcFunc";

 chomp($_=<<EOF);

 $dynimports
 $linknames
 type libcFunc uintptr

 var (
 $vardecls
 )

 $text
 EOF
 print $_;
 exit 0;
	#!/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_solaris.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 err.
	# * If go func name needs to be different than its libc name,
	# * or the function is not in libc, name could be specified
	# * at the end, after "=" sign, like
	# //sys getsockopt(s int, level int, name int, val uintptr, vallen *_Socklen) (err error) = libsocket.getsockopt

	use strict;

	my $cmdline = "mksyscall_libc.pl " . join(' ', @ARGV);
	my $errors = 0;
	my $_32bit = "";
	my $tags = ""; # build tags
	my $newtags = ""; # new style build tags
	my $aix = 0;
	my $solaris = 0;

	binmode STDOUT;

	if($ARGV[0] eq "-b32") {
	$_32bit = "big-endian";
	shift;
	} elsif($ARGV[0] eq "-l32") {
	$_32bit = "little-endian";
	shift;
	}
	if($ARGV[0] eq "-aix") {
	$aix = 1;
	shift;
	}
	if($ARGV[0] eq "-solaris") {
	$solaris = 1;
	shift;
	}
	if($ARGV[0] eq "-tags") {
	shift;
	$tags = $ARGV[0];
	shift;
	}


	if($ARGV[0] =~ /^-/) {
	print STDERR "usage: mksyscall_libc.pl [-b32 \| -l32] [-aix \| -solaris] [-tags x,y] [file ...]\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 $package = "";
	my $text = "";
	my $dynimports = "";
	my $linknames = "";
	my @vars = ();
	while(<>) {
	chomp;
	s/\s+/ /g;
	s/^\s+//;
	s/\s+$//;
	$package = $1 if !$package && /^package (\S+)$/;
	my $nonblock = /^\/\/sysnb /;
	next if !/^\/\/sys / && !$nonblock;

	my $syscalldot = "";
	$syscalldot = "syscall." if $package ne "syscall";

	# Line must be of the form
	# func Open(path string, mode int, perm int) (fd int, err error)
	# Split into name, in params, out params.
	if(!/^\/\/sys(nb)? (\w+)\(([^()])\)\s(?:\(([^()]+)\))?\s(?:=\s(?:(\w)\.)?(\w))?$/) {
	print STDERR "$ARGV:$.: malformed //sys declaration\n";
	$errors = 1;
	next;
	}
	my ($nb, $func, $in, $out, $modname, $sysname) = ($1, $2, $3, $4, $5, $6);

	# 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";

	# So file name.
	if($aix) {
	if($modname eq "") {
	$modname = "libc.a/shr_64.o";
	} else {
	print STDERR "$func: only syscall using libc are available\n";
	$errors = 1;
	next;
	}

	}
	if($solaris) {
	if($modname eq "") {
	$modname = "libc";
	}
	$modname .= ".so";

	}

	# System call name.
	if($sysname eq "") {
	$sysname = "$func";
	}

	# System call pointer variable name.
	my $sysvarname = "libc_${sysname}";

	my $strconvfunc = "BytePtrFromString";
	my $strconvtype = "*byte";

	$sysname =~ y/A-Z/a-z/; # All libc functions are lowercase.

	# Runtime import of function to allow cross-platform builds.
	$dynimports .= "//go:cgo_import_dynamic ${sysvarname} ${sysname} \"$modname\"\n";
	# Link symbol to proc address variable.
	$linknames .= "//go:linkname ${sysvarname} ${sysvarname}\n";
	# Library proc address variable.
	push @vars, $sysvarname;

	# Go function header.
	$out = join(', ', @out);
	if($out ne "") {
	$out = " ($out)";
	}
	if($text ne "") {
	$text .= "\n"
	}
	$text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out;

	# 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 $strconvtype\n";
	$text .= "\t_p$n, $errvar = $strconvfunc($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 $strconvtype\n";
	$text .= "\t_p$n, _ = $strconvfunc($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 nil in that case.
	$text .= "\tvar _p$n *$1\n";
	$text .= "\tif len($name) > 0 {\n\t\t_p$n = \&$name\[0]\n\t}\n";
	push @args, "uintptr(unsafe.Pointer(_p$n))", "uintptr(len($name))";
	$n++;
	} elsif($type eq "int64" && $_32bit ne "") {
	if($_32bit eq "big-endian") {
	push @args, "uintptr($name >> 32)", "uintptr($name)";
	} else {
	push @args, "uintptr($name)", "uintptr($name >> 32)";
	}
	} elsif($type eq "bool") {
	$text .= "\tvar _p$n uint32\n";
	$text .= "\tif $name {\n\t\t_p$n = 1\n\t} else {\n\t\t_p$n = 0\n\t}\n";
	push @args, "uintptr(_p$n)";
	$n++;
	} else {
	push @args, "uintptr($name)";
	}
	}
	my $nargs = @args;

	my $asmfuncname="";
	my $asmrawfuncname="";

	if($aix){
	$asmfuncname="syscall6";
	$asmrawfuncname="rawSyscall6";
	} else {
	$asmfuncname="sysvicall6";
	$asmrawfuncname="rawSysvicall6";
	}

	# Determine which form to use; pad args with zeros.
	my $asm = "${syscalldot}${asmfuncname}";
	if ($nonblock) {
	$asm = "${syscalldot}${asmrawfuncname}";
	}
	if(@args <= 6) {
	while(@args < 6) {
	push @args, "0";
	}
	} else {
	print STDERR "$ARGV:$.: too many arguments to system call\n";
	}

	# Actual call.
	my $args = join(', ', @args);
	my $call = "$asm(uintptr(unsafe.Pointer(&$sysvarname)), $nargs, $args)";

	# Assign return values.
	my $body = "";
	my $failexpr = "";
	my @ret = ("_", "_", "_");
	my @pout= ();
	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") {
	$reg = "e1";
	$ret[2] = $reg;
	$do_errno = 1;
	} 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") {
	$body .= "\t$name = $type($reg)\n";
	}
	}
	if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") {
	$text .= "\t$call\n";
	} else {
	$text .= "\t$ret[0], $ret[1], $ret[2] := $call\n";
	}
	$text .= $body;

	if ($do_errno) {
	$text .= "\tif e1 != 0 {\n";
	$text .= "\t\terr = errnoErr(e1)\n";
	$text .= "\t}\n";
	}
	$text .= "\treturn\n";
	$text .= "}\n";
	}

	if($errors) {
	exit 1;
	}

	# TODO: this assumes tags are just simply comma separated. For now this is all the uses.
	$newtags = $tags =~ s/,/ && /r;

	print <<EOF;
	// $cmdline
	// Code generated by the command above; DO NOT EDIT.

	//go:build $newtags
	// +build $tags

	package $package

	import "unsafe"
	EOF

	print "import \"syscall\"\n" if $package ne "syscall";

	my $vardecls = "\t" . join(",\n\t", @vars);
	$vardecls .= " libcFunc";

	chomp($_=<<EOF);

	$dynimports
	$linknames
	type libcFunc uintptr

	var (
	$vardecls
	)

	$text
	EOF
	print $_;
	exit 0;