1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
#!/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;
|
