1#!/usr/local/bin/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_libc.pl " . join(' ', @ARGV); 23my $errors = 0; 24my $_32bit = ""; 25my $tags = ""; # build tags 26my $newtags = ""; # new style build tags 27my $aix = 0; 28my $solaris = 0; 29 30binmode STDOUT; 31 32if($ARGV[0] eq "-b32") { 33 $_32bit = "big-endian"; 34 shift; 35} elsif($ARGV[0] eq "-l32") { 36 $_32bit = "little-endian"; 37 shift; 38} 39if($ARGV[0] eq "-aix") { 40 $aix = 1; 41 shift; 42} 43if($ARGV[0] eq "-solaris") { 44 $solaris = 1; 45 shift; 46} 47if($ARGV[0] eq "-tags") { 48 shift; 49 $tags = $ARGV[0]; 50 shift; 51} 52 53 54if($ARGV[0] =~ /^-/) { 55 print STDERR "usage: mksyscall_libc.pl [-b32 | -l32] [-aix | -solaris] [-tags x,y] [file ...]\n"; 56 exit 1; 57} 58 59sub parseparamlist($) { 60 my ($list) = @_; 61 $list =~ s/^\s*//; 62 $list =~ s/\s*$//; 63 if($list eq "") { 64 return (); 65 } 66 return split(/\s*,\s*/, $list); 67} 68 69sub parseparam($) { 70 my ($p) = @_; 71 if($p !~ /^(\S*) (\S*)$/) { 72 print STDERR "$ARGV:$.: malformed parameter: $p\n"; 73 $errors = 1; 74 return ("xx", "int"); 75 } 76 return ($1, $2); 77} 78 79my $package = ""; 80my $text = ""; 81my $dynimports = ""; 82my $linknames = ""; 83my @vars = (); 84while(<>) { 85 chomp; 86 s/\s+/ /g; 87 s/^\s+//; 88 s/\s+$//; 89 $package = $1 if !$package && /^package (\S+)$/; 90 my $nonblock = /^\/\/sysnb /; 91 next if !/^\/\/sys / && !$nonblock; 92 93 my $syscalldot = ""; 94 $syscalldot = "syscall." if $package ne "syscall"; 95 96 # Line must be of the form 97 # func Open(path string, mode int, perm int) (fd int, err error) 98 # Split into name, in params, out params. 99 if(!/^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*(?:(\w*)\.)?(\w*))?$/) { 100 print STDERR "$ARGV:$.: malformed //sys declaration\n"; 101 $errors = 1; 102 next; 103 } 104 my ($nb, $func, $in, $out, $modname, $sysname) = ($1, $2, $3, $4, $5, $6); 105 106 # Split argument lists on comma. 107 my @in = parseparamlist($in); 108 my @out = parseparamlist($out); 109 110 # Try in vain to keep people from editing this file. 111 # The theory is that they jump into the middle of the file 112 # without reading the header. 113 $text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n"; 114 115 # So file name. 116 if($aix) { 117 if($modname eq "") { 118 $modname = "libc.a/shr_64.o"; 119 } else { 120 print STDERR "$func: only syscall using libc are available\n"; 121 $errors = 1; 122 next; 123 } 124 125 } 126 if($solaris) { 127 if($modname eq "") { 128 $modname = "libc"; 129 } 130 $modname .= ".so"; 131 132 } 133 134 # System call name. 135 if($sysname eq "") { 136 $sysname = "$func"; 137 } 138 139 # System call pointer variable name. 140 my $sysvarname = "libc_${sysname}"; 141 142 my $strconvfunc = "BytePtrFromString"; 143 my $strconvtype = "*byte"; 144 145 $sysname =~ y/A-Z/a-z/; # All libc functions are lowercase. 146 147 # Runtime import of function to allow cross-platform builds. 148 $dynimports .= "//go:cgo_import_dynamic ${sysvarname} ${sysname} \"$modname\"\n"; 149 # Link symbol to proc address variable. 150 $linknames .= "//go:linkname ${sysvarname} ${sysvarname}\n"; 151 # Library proc address variable. 152 push @vars, $sysvarname; 153 154 # Go function header. 155 $out = join(', ', @out); 156 if($out ne "") { 157 $out = " ($out)"; 158 } 159 if($text ne "") { 160 $text .= "\n" 161 } 162 $text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out; 163 164 # Check if err return available 165 my $errvar = ""; 166 foreach my $p (@out) { 167 my ($name, $type) = parseparam($p); 168 if($type eq "error") { 169 $errvar = $name; 170 last; 171 } 172 } 173 174 # Prepare arguments to Syscall. 175 my @args = (); 176 my $n = 0; 177 foreach my $p (@in) { 178 my ($name, $type) = parseparam($p); 179 if($type =~ /^\*/) { 180 push @args, "uintptr(unsafe.Pointer($name))"; 181 } elsif($type eq "string" && $errvar ne "") { 182 $text .= "\tvar _p$n $strconvtype\n"; 183 $text .= "\t_p$n, $errvar = $strconvfunc($name)\n"; 184 $text .= "\tif $errvar != nil {\n\t\treturn\n\t}\n"; 185 push @args, "uintptr(unsafe.Pointer(_p$n))"; 186 $n++; 187 } elsif($type eq "string") { 188 print STDERR "$ARGV:$.: $func uses string arguments, but has no error return\n"; 189 $text .= "\tvar _p$n $strconvtype\n"; 190 $text .= "\t_p$n, _ = $strconvfunc($name)\n"; 191 push @args, "uintptr(unsafe.Pointer(_p$n))"; 192 $n++; 193 } elsif($type =~ /^\[\](.*)/) { 194 # Convert slice into pointer, length. 195 # Have to be careful not to take address of &a[0] if len == 0: 196 # pass nil in that case. 197 $text .= "\tvar _p$n *$1\n"; 198 $text .= "\tif len($name) > 0 {\n\t\t_p$n = \&$name\[0]\n\t}\n"; 199 push @args, "uintptr(unsafe.Pointer(_p$n))", "uintptr(len($name))"; 200 $n++; 201 } elsif($type eq "int64" && $_32bit ne "") { 202 if($_32bit eq "big-endian") { 203 push @args, "uintptr($name >> 32)", "uintptr($name)"; 204 } else { 205 push @args, "uintptr($name)", "uintptr($name >> 32)"; 206 } 207 } elsif($type eq "bool") { 208 $text .= "\tvar _p$n uint32\n"; 209 $text .= "\tif $name {\n\t\t_p$n = 1\n\t} else {\n\t\t_p$n = 0\n\t}\n"; 210 push @args, "uintptr(_p$n)"; 211 $n++; 212 } else { 213 push @args, "uintptr($name)"; 214 } 215 } 216 my $nargs = @args; 217 218 my $asmfuncname=""; 219 my $asmrawfuncname=""; 220 221 if($aix){ 222 $asmfuncname="syscall6"; 223 $asmrawfuncname="rawSyscall6"; 224 } else { 225 $asmfuncname="sysvicall6"; 226 $asmrawfuncname="rawSysvicall6"; 227 } 228 229 # Determine which form to use; pad args with zeros. 230 my $asm = "${syscalldot}${asmfuncname}"; 231 if ($nonblock) { 232 $asm = "${syscalldot}${asmrawfuncname}"; 233 } 234 if(@args <= 6) { 235 while(@args < 6) { 236 push @args, "0"; 237 } 238 } else { 239 print STDERR "$ARGV:$.: too many arguments to system call\n"; 240 } 241 242 # Actual call. 243 my $args = join(', ', @args); 244 my $call = "$asm(uintptr(unsafe.Pointer(&$sysvarname)), $nargs, $args)"; 245 246 # Assign return values. 247 my $body = ""; 248 my $failexpr = ""; 249 my @ret = ("_", "_", "_"); 250 my @pout= (); 251 my $do_errno = 0; 252 for(my $i=0; $i<@out; $i++) { 253 my $p = $out[$i]; 254 my ($name, $type) = parseparam($p); 255 my $reg = ""; 256 if($name eq "err") { 257 $reg = "e1"; 258 $ret[2] = $reg; 259 $do_errno = 1; 260 } else { 261 $reg = sprintf("r%d", $i); 262 $ret[$i] = $reg; 263 } 264 if($type eq "bool") { 265 $reg = "$reg != 0"; 266 } 267 if($type eq "int64" && $_32bit ne "") { 268 # 64-bit number in r1:r0 or r0:r1. 269 if($i+2 > @out) { 270 print STDERR "$ARGV:$.: not enough registers for int64 return\n"; 271 } 272 if($_32bit eq "big-endian") { 273 $reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i, $i+1); 274 } else { 275 $reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i+1, $i); 276 } 277 $ret[$i] = sprintf("r%d", $i); 278 $ret[$i+1] = sprintf("r%d", $i+1); 279 } 280 if($reg ne "e1") { 281 $body .= "\t$name = $type($reg)\n"; 282 } 283 } 284 if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") { 285 $text .= "\t$call\n"; 286 } else { 287 $text .= "\t$ret[0], $ret[1], $ret[2] := $call\n"; 288 } 289 $text .= $body; 290 291 if ($do_errno) { 292 $text .= "\tif e1 != 0 {\n"; 293 $text .= "\t\terr = errnoErr(e1)\n"; 294 $text .= "\t}\n"; 295 } 296 $text .= "\treturn\n"; 297 $text .= "}\n"; 298} 299 300if($errors) { 301 exit 1; 302} 303 304# TODO: this assumes tags are just simply comma separated. For now this is all the uses. 305$newtags = $tags =~ s/,/ && /r; 306 307print <<EOF; 308// $cmdline 309// Code generated by the command above; DO NOT EDIT. 310 311//go:build $newtags 312 313package $package 314 315import "unsafe" 316EOF 317 318print "import \"syscall\"\n" if $package ne "syscall"; 319 320my $vardecls = "\t" . join(",\n\t", @vars); 321$vardecls .= " libcFunc"; 322 323chomp($_=<<EOF); 324 325$dynimports 326$linknames 327type libcFunc uintptr 328 329var ( 330$vardecls 331) 332 333$text 334EOF 335print $_; 336exit 0; 337