1#!/usr/bin/env perl
2# Copyright 2009 The Go Authors. All rights reserved.
3# Use of this source code is governed by a BSD-style
4# license that can be found in the LICENSE file.
5
6# This program reads a file containing function prototypes
7# (like syscall_solaris.go) and generates system call bodies.
8# The prototypes are marked by lines beginning with "//sys"
9# and read like func declarations if //sys is replaced by func, but:
10#	* The parameter lists must give a name for each argument.
11#	  This includes return parameters.
12#	* The parameter lists must give a type for each argument:
13#	  the (x, y, z int) shorthand is not allowed.
14#	* If the return parameter is an error number, it must be named err.
15#	* If go func name needs to be different than its libc name,
16#	* or the function is not in libc, name could be specified
17#	* at the end, after "=" sign, like
18#	  //sys getsockopt(s int, level int, name int, val uintptr, vallen *_Socklen) (err error) = libsocket.getsockopt
19
20use strict;
21
22my $cmdline = "mksyscall_solaris.pl " . join(' ', @ARGV);
23my $errors = 0;
24my $_32bit = "";
25my $tags = "";  # build tags
26
27binmode STDOUT;
28
29if($ARGV[0] eq "-b32") {
30	$_32bit = "big-endian";
31	shift;
32} elsif($ARGV[0] eq "-l32") {
33	$_32bit = "little-endian";
34	shift;
35}
36if($ARGV[0] eq "-tags") {
37	shift;
38	$tags = $ARGV[0];
39	shift;
40}
41
42if($ARGV[0] =~ /^-/) {
43	print STDERR "usage: mksyscall_solaris.pl [-b32 | -l32] [-tags x,y] [file ...]\n";
44	exit 1;
45}
46
47sub parseparamlist($) {
48	my ($list) = @_;
49	$list =~ s/^\s*//;
50	$list =~ s/\s*$//;
51	if($list eq "") {
52		return ();
53	}
54	return split(/\s*,\s*/, $list);
55}
56
57sub parseparam($) {
58	my ($p) = @_;
59	if($p !~ /^(\S*) (\S*)$/) {
60		print STDERR "$ARGV:$.: malformed parameter: $p\n";
61		$errors = 1;
62		return ("xx", "int");
63	}
64	return ($1, $2);
65}
66
67my $package = "";
68my $text = "";
69my $dynimports = "";
70my $linknames = "";
71my @vars = ();
72while(<>) {
73	chomp;
74	s/\s+/ /g;
75	s/^\s+//;
76	s/\s+$//;
77	$package = $1 if !$package && /^package (\S+)$/;
78	my $nonblock = /^\/\/sysnb /;
79	next if !/^\/\/sys / && !$nonblock;
80
81	# Line must be of the form
82	#	func Open(path string, mode int, perm int) (fd int, err error)
83	# Split into name, in params, out params.
84	if(!/^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*(?:(\w*)\.)?(\w*))?$/) {
85		print STDERR "$ARGV:$.: malformed //sys declaration\n";
86		$errors = 1;
87		next;
88	}
89	my ($nb, $func, $in, $out, $modname, $sysname) = ($1, $2, $3, $4, $5, $6);
90
91	# Split argument lists on comma.
92	my @in = parseparamlist($in);
93	my @out = parseparamlist($out);
94
95	# Try in vain to keep people from editing this file.
96	# The theory is that they jump into the middle of the file
97	# without reading the header.
98	$text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n";
99
100	# So file name.
101	if($modname eq "") {
102		$modname = "libc";
103	}
104
105	# System call name.
106	if($sysname eq "") {
107		$sysname = "$func";
108	}
109
110	# System call pointer variable name.
111	my $sysvarname = "proc$sysname";
112
113	my $strconvfunc = "BytePtrFromString";
114	my $strconvtype = "*byte";
115
116	$sysname =~ y/A-Z/a-z/; # All libc functions are lowercase.
117
118	# Runtime import of function to allow cross-platform builds.
119	$dynimports .= "//go:cgo_import_dynamic libc_${sysname} ${sysname} \"$modname.so\"\n";
120	# Link symbol to proc address variable.
121	$linknames .= "//go:linkname ${sysvarname} libc_${sysname}\n";
122	# Library proc address variable.
123	push @vars, $sysvarname;
124
125	# Go function header.
126	$out = join(', ', @out);
127	if($out ne "") {
128		$out = " ($out)";
129	}
130	if($text ne "") {
131		$text .= "\n"
132	}
133	$text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out;
134
135	# Check if err return available
136	my $errvar = "";
137	foreach my $p (@out) {
138		my ($name, $type) = parseparam($p);
139		if($type eq "error") {
140			$errvar = $name;
141			last;
142		}
143	}
144
145	# Prepare arguments to Syscall.
146	my @args = ();
147	my $n = 0;
148	foreach my $p (@in) {
149		my ($name, $type) = parseparam($p);
150		if($type =~ /^\*/) {
151			push @args, "uintptr(unsafe.Pointer($name))";
152		} elsif($type eq "string" && $errvar ne "") {
153			$text .= "\tvar _p$n $strconvtype\n";
154			$text .= "\t_p$n, $errvar = $strconvfunc($name)\n";
155			$text .= "\tif $errvar != nil {\n\t\treturn\n\t}\n";
156			push @args, "uintptr(unsafe.Pointer(_p$n))";
157			$n++;
158		} elsif($type eq "string") {
159			print STDERR "$ARGV:$.: $func uses string arguments, but has no error return\n";
160			$text .= "\tvar _p$n $strconvtype\n";
161			$text .= "\t_p$n, _ = $strconvfunc($name)\n";
162			push @args, "uintptr(unsafe.Pointer(_p$n))";
163			$n++;
164		} elsif($type =~ /^\[\](.*)/) {
165			# Convert slice into pointer, length.
166			# Have to be careful not to take address of &a[0] if len == 0:
167			# pass nil in that case.
168			$text .= "\tvar _p$n *$1\n";
169			$text .= "\tif len($name) > 0 {\n\t\t_p$n = \&$name\[0]\n\t}\n";
170			push @args, "uintptr(unsafe.Pointer(_p$n))", "uintptr(len($name))";
171			$n++;
172		} elsif($type eq "int64" && $_32bit ne "") {
173			if($_32bit eq "big-endian") {
174				push @args, "uintptr($name >> 32)", "uintptr($name)";
175			} else {
176				push @args, "uintptr($name)", "uintptr($name >> 32)";
177			}
178		} elsif($type eq "bool") {
179 			$text .= "\tvar _p$n uint32\n";
180			$text .= "\tif $name {\n\t\t_p$n = 1\n\t} else {\n\t\t_p$n = 0\n\t}\n";
181			push @args, "uintptr(_p$n)";
182			$n++;
183		} else {
184			push @args, "uintptr($name)";
185		}
186	}
187	my $nargs = @args;
188
189	# Determine which form to use; pad args with zeros.
190	my $asm = "sysvicall6";
191	if ($nonblock) {
192		$asm = "rawSysvicall6";
193	}
194	if(@args <= 6) {
195		while(@args < 6) {
196			push @args, "0";
197		}
198	} else {
199		print STDERR "$ARGV:$.: too many arguments to system call\n";
200	}
201
202	# Actual call.
203	my $args = join(', ', @args);
204	my $call = "$asm(uintptr(unsafe.Pointer(&$sysvarname)), $nargs, $args)";
205
206	# Assign return values.
207	my $body = "";
208	my $failexpr = "";
209	my @ret = ("_", "_", "_");
210	my @pout= ();
211	my $do_errno = 0;
212	for(my $i=0; $i<@out; $i++) {
213		my $p = $out[$i];
214		my ($name, $type) = parseparam($p);
215		my $reg = "";
216		if($name eq "err") {
217			$reg = "e1";
218			$ret[2] = $reg;
219			$do_errno = 1;
220		} else {
221			$reg = sprintf("r%d", $i);
222			$ret[$i] = $reg;
223		}
224		if($type eq "bool") {
225			$reg = "$reg != 0";
226		}
227		if($type eq "int64" && $_32bit ne "") {
228			# 64-bit number in r1:r0 or r0:r1.
229			if($i+2 > @out) {
230				print STDERR "$ARGV:$.: not enough registers for int64 return\n";
231			}
232			if($_32bit eq "big-endian") {
233				$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i, $i+1);
234			} else {
235				$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i+1, $i);
236			}
237			$ret[$i] = sprintf("r%d", $i);
238			$ret[$i+1] = sprintf("r%d", $i+1);
239		}
240		if($reg ne "e1") {
241			$body .= "\t$name = $type($reg)\n";
242		}
243	}
244	if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") {
245		$text .= "\t$call\n";
246	} else {
247		$text .= "\t$ret[0], $ret[1], $ret[2] := $call\n";
248	}
249	$text .= $body;
250
251	if ($do_errno) {
252		$text .= "\tif e1 != 0 {\n";
253		$text .= "\t\terr = e1\n";
254		$text .= "\t}\n";
255	}
256	$text .= "\treturn\n";
257	$text .= "}\n";
258}
259
260if($errors) {
261	exit 1;
262}
263
264print <<EOF;
265// $cmdline
266// Code generated by the command above; see README.md. DO NOT EDIT.
267
268// +build $tags
269
270package $package
271
272import (
273	"syscall"
274	"unsafe"
275)
276EOF
277
278print "import \"golang.org/x/sys/unix\"\n" if $package ne "unix";
279
280my $vardecls = "\t" . join(",\n\t", @vars);
281$vardecls .= " syscallFunc";
282
283chomp($_=<<EOF);
284
285$dynimports
286$linknames
287var (
288$vardecls
289)
290
291$text
292EOF
293print $_;
294exit 0;
295