blob: 79d19d0d0c630dedad96a497e25748132f10ac6f [file] [log] [blame]
#!/usr/bin/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_darwin.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 errno.
$cmdline = "mksyscall.sh " . join(' ', @ARGV);
$errors = 0;
$_32bit = "";
$nacl = 0;
if($ARGV[0] eq "-b32") {
$_32bit = "big-endian";
shift;
} elsif($ARGV[0] eq "-l32") {
$_32bit = "little-endian";
shift;
}
if($ARGV[0] eq "-nacl") {
$nacl = 1;
shift;
}
if($ARGV[0] =~ /^-/) {
print STDERR "usage: mksyscall.sh [-b32 | -l32] [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);
}
$text = "";
while(<>) {
chomp;
s/\s+/ /g;
s/^\s+//;
s/\s+$//;
next if !/^\/\/sys /;
# Line must be of the form
# func Open(path string, mode int, perm int) (fd int, errno int)
# Split into name, in params, out params.
if(!/^\/\/sys (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*(SYS_[A-Z0-9_]+))?$/) {
print STDERR "$ARGV:$.: malformed //sys declaration\n";
$errors = 1;
next;
}
my ($func, $in, $out, $sysname) = ($1, $2, $3, $4);
# Split argument lists on comma.
my @in = parseparamlist($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";
# Go function header.
my $out_decl = @out ? sprintf(" (%s)", join(', ', @out)) : "";
$text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out_decl;
# 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($type eq "string") {
push @args, "uintptr(unsafe.Pointer(StringBytePtr($name)))";
} 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 unsafe.Pointer\n";
$text .= "\tif len($name) > 0 {\n\t\t_p$n = unsafe.Pointer(\&${name}[0])\n\t}";
if($nacl) {
# NaCl rejects zero length write with nil pointer,
# so use non-nil pointer.
$text .= " else {\n\t\t_p$n = unsafe.Pointer(&_zero[0])\n\t}";
}
$text .= "\n";
push @args, "uintptr(_p$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)";
}
} else {
push @args, "uintptr($name)";
}
}
# Determine which form to use; pad args with zeros.
my $asm = "Syscall";
if(@args <= 3) {
while(@args < 3) {
push @args, "0";
}
} elsif(@args <= 6) {
$asm = "Syscall6";
while(@args < 6) {
push @args, "0";
}
} else {
print STDERR "$ARGV:$.: too many arguments to system call\n";
}
# System call number.
if($sysname eq "") {
$sysname = "SYS_$func";
$sysname =~ s/([a-z])([A-Z])/${1}_$2/g; # turn FooBar into Foo_Bar
$sysname =~ y/a-z/A-Z/;
}
# Actual call.
my $args = join(', ', @args);
my $call = "$asm($sysname, $args)";
# Assign return values.
my $body = "";
my @ret = ("_", "_", "_");
for(my $i=0; $i<@out; $i++) {
my $p = $out[$i];
my ($name, $type) = parseparam($p);
my $reg = "";
if($name eq "errno") {
$reg = "e1";
$ret[2] = $reg;
} 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);
}
$body .= "\t$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;
$text .= "\treturn\n";
$text .= "}\n\n";
}
chomp $text;
chomp $text;
if($errors) {
exit 1;
}
print <<EOF;
// $cmdline
// MACHINE GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
package syscall
import "unsafe"
$text
EOF
exit 0;