1 files changed, 336 insertions, 0 deletions
diff --git a/src/syscall/mksyscall_libc.pl b/src/syscall/mksyscall_libc.pl
new file mode 100755
index 0000000..3731476
--- /dev/null
+++ b/src/syscall/mksyscall_libc.pl
@@ -0,0 +1,336 @@
+#!/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
+
+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;