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_darwin.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 errno.
15
16# A line beginning with //sysnb is like //sys, except that the
17# goroutine will not be suspended during the execution of the system
18# call.  This must only be used for system calls which can never
19# block, as otherwise the system call could cause all goroutines to
20# hang.
21
22use strict;
23
24my $cmdline = "mksyscall.pl " . join(' ', @ARGV);
25my $errors = 0;
26my $_32bit = "";
27my $plan9 = 0;
28my $openbsd = 0;
29my $netbsd = 0;
30my $dragonfly = 0;
31my $nacl = 0;
32my $arm = 0; # 64-bit value should use (even, odd)-pair
33
34if($ARGV[0] eq "-b32") {
35	$_32bit = "big-endian";
36	shift;
37} elsif($ARGV[0] eq "-l32") {
38	$_32bit = "little-endian";
39	shift;
40}
41if($ARGV[0] eq "-plan9") {
42	$plan9 = 1;
43	shift;
44}
45if($ARGV[0] eq "-openbsd") {
46	$openbsd = 1;
47	shift;
48}
49if($ARGV[0] eq "-netbsd") {
50	$netbsd = 1;
51	shift;
52}
53if($ARGV[0] eq "-dragonfly") {
54	$dragonfly = 1;
55	shift;
56}
57if($ARGV[0] eq "-nacl") {
58	$nacl = 1;
59	shift;
60}
61if($ARGV[0] eq "-arm") {
62	$arm = 1;
63	shift;
64}
65
66if($ARGV[0] =~ /^-/) {
67	print STDERR "usage: mksyscall.pl [-b32 | -l32] [file ...]\n";
68	exit 1;
69}
70
71sub parseparamlist($) {
72	my ($list) = @_;
73	$list =~ s/^\s*//;
74	$list =~ s/\s*$//;
75	if($list eq "") {
76		return ();
77	}
78	return split(/\s*,\s*/, $list);
79}
80
81sub parseparam($) {
82	my ($p) = @_;
83	if($p !~ /^(\S*) (\S*)$/) {
84		print STDERR "$ARGV:$.: malformed parameter: $p\n";
85		$errors = 1;
86		return ("xx", "int");
87	}
88	return ($1, $2);
89}
90
91my $text = "";
92while(<>) {
93	chomp;
94	s/\s+/ /g;
95	s/^\s+//;
96	s/\s+$//;
97	my $nonblock = /^\/\/sysnb /;
98	next if !/^\/\/sys / && !$nonblock;
99
100	# Line must be of the form
101	#	func Open(path string, mode int, perm int) (fd int, errno error)
102	# Split into name, in params, out params.
103	if(!/^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*((?i)_?SYS_[A-Z0-9_]+))?$/) {
104		print STDERR "$ARGV:$.: malformed //sys declaration\n";
105		$errors = 1;
106		next;
107	}
108	my ($func, $in, $out, $sysname) = ($2, $3, $4, $5);
109
110	# Split argument lists on comma.
111	my @in = parseparamlist($in);
112	my @out = parseparamlist($out);
113
114	# Try in vain to keep people from editing this file.
115	# The theory is that they jump into the middle of the file
116	# without reading the header.
117	$text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n";
118
119	# Go function header.
120	my $out_decl = @out ? sprintf(" (%s)", join(', ', @out)) : "";
121	$text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out_decl;
122
123	# Check if err return available
124	my $errvar = "";
125	foreach my $p (@out) {
126		my ($name, $type) = parseparam($p);
127		if($type eq "error") {
128			$errvar = $name;
129			last;
130		}
131	}
132
133	# Prepare arguments to Syscall.
134	my @args = ();
135	my @uses = ();
136	my $n = 0;
137	foreach my $p (@in) {
138		my ($name, $type) = parseparam($p);
139		if($type =~ /^\*/) {
140			push @args, "uintptr(unsafe.Pointer($name))";
141		} elsif($type eq "string" && $errvar ne "") {
142			$text .= "\tvar _p$n *byte\n";
143			$text .= "\t_p$n, $errvar = BytePtrFromString($name)\n";
144			$text .= "\tif $errvar != nil {\n\t\treturn\n\t}\n";
145			push @args, "uintptr(unsafe.Pointer(_p$n))";
146			push @uses, "use(unsafe.Pointer(_p$n))";
147			$n++;
148		} elsif($type eq "string") {
149			print STDERR "$ARGV:$.: $func uses string arguments, but has no error return\n";
150			$text .= "\tvar _p$n *byte\n";
151			$text .= "\t_p$n, _ = BytePtrFromString($name)\n";
152			push @args, "uintptr(unsafe.Pointer(_p$n))";
153			push @uses, "use(unsafe.Pointer(_p$n))";
154			$n++;
155		} elsif($type =~ /^\[\](.*)/) {
156			# Convert slice into pointer, length.
157			# Have to be careful not to take address of &a[0] if len == 0:
158			# pass dummy pointer in that case.
159			# Used to pass nil, but some OSes or simulators reject write(fd, nil, 0).
160			$text .= "\tvar _p$n unsafe.Pointer\n";
161			$text .= "\tif len($name) > 0 {\n\t\t_p$n = unsafe.Pointer(\&${name}[0])\n\t}";
162			$text .= " else {\n\t\t_p$n = unsafe.Pointer(&_zero)\n\t}";
163			$text .= "\n";
164			push @args, "uintptr(_p$n)", "uintptr(len($name))";
165			$n++;
166		} elsif($type eq "int64" && ($openbsd || $netbsd)) {
167			push @args, "0";
168			if($_32bit eq "big-endian") {
169				push @args, "uintptr($name>>32)", "uintptr($name)";
170			} elsif($_32bit eq "little-endian") {
171				push @args, "uintptr($name)", "uintptr($name>>32)";
172			} else {
173				push @args, "uintptr($name)";
174			}
175		} elsif($type eq "int64" && $dragonfly) {
176			if ($func !~ /^extp(read|write)/i) {
177				push @args, "0";
178			}
179			if($_32bit eq "big-endian") {
180				push @args, "uintptr($name>>32)", "uintptr($name)";
181			} elsif($_32bit eq "little-endian") {
182				push @args, "uintptr($name)", "uintptr($name>>32)";
183			} else {
184				push @args, "uintptr($name)";
185			}
186		} elsif($type eq "int64" && $_32bit ne "") {
187			if(@args % 2 && $arm) {
188				# arm abi specifies 64-bit argument uses
189				# (even, odd) pair
190				push @args, "0"
191			}
192			if($_32bit eq "big-endian") {
193				push @args, "uintptr($name>>32)", "uintptr($name)";
194			} else {
195				push @args, "uintptr($name)", "uintptr($name>>32)";
196			}
197		} else {
198			push @args, "uintptr($name)";
199		}
200	}
201
202	# Determine which form to use; pad args with zeros.
203	my $asm = "Syscall";
204	if ($nonblock) {
205		$asm = "RawSyscall";
206	}
207	if(@args <= 3) {
208		while(@args < 3) {
209			push @args, "0";
210		}
211	} elsif(@args <= 6) {
212		$asm .= "6";
213		while(@args < 6) {
214			push @args, "0";
215		}
216	} elsif(@args <= 9) {
217		$asm .= "9";
218		while(@args < 9) {
219			push @args, "0";
220		}
221	} else {
222		print STDERR "$ARGV:$.: too many arguments to system call\n";
223	}
224
225	# System call number.
226	if($sysname eq "") {
227		$sysname = "SYS_$func";
228		$sysname =~ s/([a-z])([A-Z])/${1}_$2/g;	# turn FooBar into Foo_Bar
229		$sysname =~ y/a-z/A-Z/;
230		if($nacl) {
231			$sysname =~ y/A-Z/a-z/;
232		}
233	}
234
235	# Actual call.
236	my $args = join(', ', @args);
237	my $call = "$asm($sysname, $args)";
238
239	# Assign return values.
240	my $body = "";
241	my @ret = ("_", "_", "_");
242	my $do_errno = 0;
243	for(my $i=0; $i<@out; $i++) {
244		my $p = $out[$i];
245		my ($name, $type) = parseparam($p);
246		my $reg = "";
247		if($name eq "err" && !$plan9) {
248			$reg = "e1";
249			$ret[2] = $reg;
250			$do_errno = 1;
251		} elsif($name eq "err" && $plan9) {
252			$ret[0] = "r0";
253			$ret[2] = "e1";
254			next;
255		} else {
256			$reg = sprintf("r%d", $i);
257			$ret[$i] = $reg;
258		}
259		if($type eq "bool") {
260			$reg = "$reg != 0";
261		}
262		if($type eq "int64" && $_32bit ne "") {
263			# 64-bit number in r1:r0 or r0:r1.
264			if($i+2 > @out) {
265				print STDERR "$ARGV:$.: not enough registers for int64 return\n";
266			}
267			if($_32bit eq "big-endian") {
268				$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i, $i+1);
269			} else {
270				$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i+1, $i);
271			}
272			$ret[$i] = sprintf("r%d", $i);
273			$ret[$i+1] = sprintf("r%d", $i+1);
274		}
275		if($reg ne "e1" || $plan9) {
276			$body .= "\t$name = $type($reg)\n";
277		}
278	}
279	if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") {
280		$text .= "\t$call\n";
281	} else {
282		$text .= "\t$ret[0], $ret[1], $ret[2] := $call\n";
283	}
284	foreach my $use (@uses) {
285		$text .= "\t$use\n";
286	}
287	$text .= $body;
288
289	if ($plan9 && $ret[2] eq "e1") {
290		$text .= "\tif int32(r0) == -1 {\n";
291		$text .= "\t\terr = e1\n";
292		$text .= "\t}\n";
293	} elsif ($do_errno) {
294		$text .= "\tif e1 != 0 {\n";
295		$text .= "\t\terr = errnoErr(e1)\n";
296		$text .= "\t}\n";
297	}
298	$text .= "\treturn\n";
299	$text .= "}\n\n";
300}
301
302chomp $text;
303chomp $text;
304
305if($errors) {
306	exit 1;
307}
308
309print <<EOF;
310// $cmdline
311// MACHINE GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
312
313package syscall
314
315import "unsafe"
316
317$text
318EOF
319exit 0;
320