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 $darwin = 0; 29my $openbsd = 0; 30my $netbsd = 0; 31my $dragonfly = 0; 32my $arm = 0; # 64-bit value should use (even, odd)-pair 33my $tags = ""; # build tags 34 35if($ARGV[0] eq "-b32") { 36 $_32bit = "big-endian"; 37 shift; 38} elsif($ARGV[0] eq "-l32") { 39 $_32bit = "little-endian"; 40 shift; 41} 42if($ARGV[0] eq "-plan9") { 43 $plan9 = 1; 44 shift; 45} 46if($ARGV[0] eq "-darwin") { 47 $darwin = 1; 48 shift; 49} 50if($ARGV[0] eq "-openbsd") { 51 $openbsd = 1; 52 shift; 53} 54if($ARGV[0] eq "-netbsd") { 55 $netbsd = 1; 56 shift; 57} 58if($ARGV[0] eq "-dragonfly") { 59 $dragonfly = 1; 60 shift; 61} 62if($ARGV[0] eq "-arm") { 63 $arm = 1; 64 shift; 65} 66if($ARGV[0] eq "-tags") { 67 shift; 68 $tags = $ARGV[0]; 69 shift; 70} 71 72if($ARGV[0] =~ /^-/) { 73 print STDERR "usage: mksyscall.pl [-b32 | -l32] [-tags x,y] [file ...]\n"; 74 exit 1; 75} 76 77sub parseparamlist($) { 78 my ($list) = @_; 79 $list =~ s/^\s*//; 80 $list =~ s/\s*$//; 81 if($list eq "") { 82 return (); 83 } 84 return split(/\s*,\s*/, $list); 85} 86 87sub parseparam($) { 88 my ($p) = @_; 89 if($p !~ /^(\S*) (\S*)$/) { 90 print STDERR "$ARGV:$.: malformed parameter: $p\n"; 91 $errors = 1; 92 return ("xx", "int"); 93 } 94 return ($1, $2); 95} 96 97# set of trampolines we've already generated 98my %trampolines; 99 100my $text = ""; 101while(<>) { 102 chomp; 103 s/\s+/ /g; 104 s/^\s+//; 105 s/\s+$//; 106 my $nonblock = /^\/\/sysnb /; 107 next if !/^\/\/sys / && !$nonblock; 108 109 # Line must be of the form 110 # func Open(path string, mode int, perm int) (fd int, errno error) 111 # Split into name, in params, out params. 112 if(!/^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*((?i)_?SYS_[A-Z0-9_]+))?$/) { 113 print STDERR "$ARGV:$.: malformed //sys declaration\n"; 114 $errors = 1; 115 next; 116 } 117 my ($func, $in, $out, $sysname) = ($2, $3, $4, $5); 118 119 # Split argument lists on comma. 120 my @in = parseparamlist($in); 121 my @out = parseparamlist($out); 122 123 # Try in vain to keep people from editing this file. 124 # The theory is that they jump into the middle of the file 125 # without reading the header. 126 $text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n"; 127 128 if ($darwin && $func eq "ptrace") { 129 # The ptrace function is called from forkAndExecInChild where stack 130 # growth is forbidden. 131 $text .= "//go:nosplit\n" 132 } 133 134 # Go function header. 135 my $out_decl = @out ? sprintf(" (%s)", join(', ', @out)) : ""; 136 $text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out_decl; 137 138 # Check if err return available 139 my $errvar = ""; 140 foreach my $p (@out) { 141 my ($name, $type) = parseparam($p); 142 if($type eq "error") { 143 $errvar = $name; 144 last; 145 } 146 } 147 148 # Prepare arguments to Syscall. 149 my @args = (); 150 my $n = 0; 151 foreach my $p (@in) { 152 my ($name, $type) = parseparam($p); 153 if($type =~ /^\*/) { 154 push @args, "uintptr(unsafe.Pointer($name))"; 155 } elsif($type eq "string" && $errvar ne "") { 156 $text .= "\tvar _p$n *byte\n"; 157 $text .= "\t_p$n, $errvar = BytePtrFromString($name)\n"; 158 $text .= "\tif $errvar != nil {\n\t\treturn\n\t}\n"; 159 push @args, "uintptr(unsafe.Pointer(_p$n))"; 160 $n++; 161 } elsif($type eq "string") { 162 print STDERR "$ARGV:$.: $func uses string arguments, but has no error return\n"; 163 $text .= "\tvar _p$n *byte\n"; 164 $text .= "\t_p$n, _ = BytePtrFromString($name)\n"; 165 push @args, "uintptr(unsafe.Pointer(_p$n))"; 166 $n++; 167 } elsif($type =~ /^\[\](.*)/) { 168 # Convert slice into pointer, length. 169 # Have to be careful not to take address of &a[0] if len == 0: 170 # pass dummy pointer in that case. 171 # Used to pass nil, but some OSes or simulators reject write(fd, nil, 0). 172 $text .= "\tvar _p$n unsafe.Pointer\n"; 173 $text .= "\tif len($name) > 0 {\n\t\t_p$n = unsafe.Pointer(\&${name}[0])\n\t}"; 174 $text .= " else {\n\t\t_p$n = unsafe.Pointer(&_zero)\n\t}"; 175 $text .= "\n"; 176 push @args, "uintptr(_p$n)", "uintptr(len($name))"; 177 $n++; 178 } elsif($type eq "int64" && ($openbsd || $netbsd)) { 179 push @args, "0"; 180 if($_32bit eq "big-endian") { 181 push @args, "uintptr($name>>32)", "uintptr($name)"; 182 } elsif($_32bit eq "little-endian") { 183 push @args, "uintptr($name)", "uintptr($name>>32)"; 184 } else { 185 push @args, "uintptr($name)"; 186 } 187 } elsif($type eq "int64" && $dragonfly) { 188 if ($func !~ /^extp(read|write)/i) { 189 push @args, "0"; 190 } 191 if($_32bit eq "big-endian") { 192 push @args, "uintptr($name>>32)", "uintptr($name)"; 193 } elsif($_32bit eq "little-endian") { 194 push @args, "uintptr($name)", "uintptr($name>>32)"; 195 } else { 196 push @args, "uintptr($name)"; 197 } 198 } elsif($type eq "int64" && $_32bit ne "") { 199 if(@args % 2 && $arm) { 200 # arm abi specifies 64-bit argument uses 201 # (even, odd) pair 202 push @args, "0" 203 } 204 if($_32bit eq "big-endian") { 205 push @args, "uintptr($name>>32)", "uintptr($name)"; 206 } else { 207 push @args, "uintptr($name)", "uintptr($name>>32)"; 208 } 209 } else { 210 push @args, "uintptr($name)"; 211 } 212 } 213 214 # Determine which form to use; pad args with zeros. 215 my $asm = "Syscall"; 216 if ($nonblock) { 217 if ($errvar eq "" && $ENV{'GOOS'} eq "linux") { 218 $asm = "rawSyscallNoError"; 219 } else { 220 $asm = "RawSyscall"; 221 } 222 } 223 if ($darwin) { 224 # Call unexported syscall functions (which take 225 # libc functions instead of syscall numbers). 226 $asm = lcfirst($asm); 227 } 228 if(@args <= 3) { 229 while(@args < 3) { 230 push @args, "0"; 231 } 232 } elsif(@args <= 6) { 233 $asm .= "6"; 234 while(@args < 6) { 235 push @args, "0"; 236 } 237 } elsif(@args <= 9) { 238 $asm .= "9"; 239 while(@args < 9) { 240 push @args, "0"; 241 } 242 } else { 243 print STDERR "$ARGV:$.: too many arguments to system call\n"; 244 } 245 246 if ($darwin) { 247 # Use extended versions for calls that generate a 64-bit result. 248 my ($name, $type) = parseparam($out[0]); 249 if ($type eq "int64" || ($type eq "uintptr" && $_32bit eq "")) { 250 $asm .= "X"; 251 } 252 } 253 254 # System call number. 255 my $funcname = ""; 256 if($sysname eq "") { 257 $sysname = "SYS_$func"; 258 $sysname =~ s/([a-z])([A-Z])/${1}_$2/g; # turn FooBar into Foo_Bar 259 $sysname =~ y/a-z/A-Z/; 260 if($darwin) { 261 $sysname =~ y/A-Z/a-z/; 262 $sysname = substr $sysname, 4; 263 $funcname = "libc_$sysname"; 264 } 265 } 266 if($darwin) { 267 if($funcname eq "") { 268 $sysname = substr $sysname, 4; 269 $funcname = "libc_$sysname"; 270 } 271 $sysname = "funcPC(${funcname}_trampoline)"; 272 } 273 274 # Actual call. 275 my $args = join(', ', @args); 276 my $call = "$asm($sysname, $args)"; 277 278 # Assign return values. 279 my $body = ""; 280 my @ret = ("_", "_", "_"); 281 my $do_errno = 0; 282 for(my $i=0; $i<@out; $i++) { 283 my $p = $out[$i]; 284 my ($name, $type) = parseparam($p); 285 my $reg = ""; 286 if($name eq "err" && !$plan9) { 287 $reg = "e1"; 288 $ret[2] = $reg; 289 $do_errno = 1; 290 } elsif($name eq "err" && $plan9) { 291 $ret[0] = "r0"; 292 $ret[2] = "e1"; 293 next; 294 } else { 295 $reg = sprintf("r%d", $i); 296 $ret[$i] = $reg; 297 } 298 if($type eq "bool") { 299 $reg = "$reg != 0"; 300 } 301 if($type eq "int64" && $_32bit ne "") { 302 # 64-bit number in r1:r0 or r0:r1. 303 if($i+2 > @out) { 304 print STDERR "$ARGV:$.: not enough registers for int64 return\n"; 305 } 306 if($_32bit eq "big-endian") { 307 $reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i, $i+1); 308 } else { 309 $reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i+1, $i); 310 } 311 $ret[$i] = sprintf("r%d", $i); 312 $ret[$i+1] = sprintf("r%d", $i+1); 313 } 314 if($reg ne "e1" || $plan9) { 315 $body .= "\t$name = $type($reg)\n"; 316 } 317 } 318 if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") { 319 $text .= "\t$call\n"; 320 } else { 321 if ($errvar eq "" && $ENV{'GOOS'} eq "linux") { 322 # raw syscall without error on Linux, see golang.org/issue/22924 323 $text .= "\t$ret[0], $ret[1] := $call\n"; 324 } else { 325 $text .= "\t$ret[0], $ret[1], $ret[2] := $call\n"; 326 } 327 } 328 $text .= $body; 329 330 if ($plan9 && $ret[2] eq "e1") { 331 $text .= "\tif int32(r0) == -1 {\n"; 332 $text .= "\t\terr = e1\n"; 333 $text .= "\t}\n"; 334 } elsif ($do_errno) { 335 $text .= "\tif e1 != 0 {\n"; 336 $text .= "\t\terr = errnoErr(e1)\n"; 337 $text .= "\t}\n"; 338 } 339 $text .= "\treturn\n"; 340 $text .= "}\n\n"; 341 if($darwin) { 342 if (not exists $trampolines{$funcname}) { 343 $trampolines{$funcname} = 1; 344 # The assembly trampoline that jumps to the libc routine. 345 $text .= "func ${funcname}_trampoline()\n"; 346 # Map syscall.funcname to just plain funcname. 347 # (The jump to this function is in the assembly trampoline, generated by mksyscallasm_darwin.go.) 348 $text .= "//go:linkname $funcname $funcname\n"; 349 # Tell the linker that funcname can be found in libSystem using varname without the libc_ prefix. 350 my $basename = substr $funcname, 5; 351 $text .= "//go:cgo_import_dynamic $funcname $basename \"/usr/lib/libSystem.B.dylib\"\n\n"; 352 } 353 } 354} 355 356chomp $text; 357chomp $text; 358 359if($errors) { 360 exit 1; 361} 362 363print <<EOF; 364// $cmdline 365// Code generated by the command above; DO NOT EDIT. 366 367// +build $tags 368 369package syscall 370 371import "unsafe" 372 373$text 374EOF 375exit 0; 376