#!/usr/bin/env 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. # A line beginning with //sysnb is like //sys, except that the # goroutine will not be suspended during the execution of the system # call. This must only be used for system calls which can never # block, as otherwise the system call could cause all goroutines to # hang. use strict; my $cmdline = "mksyscall.pl " . join(' ', @ARGV); my $errors = 0; my $_32bit = ""; my $plan9 = 0; my $openbsd = 0; my $netbsd = 0; my $dragonfly = 0; my $arm = 0; # 64-bit value should use (even, odd)-pair if($ARGV[0] eq "-b32") { $_32bit = "big-endian"; shift; } elsif($ARGV[0] eq "-l32") { $_32bit = "little-endian"; shift; } if($ARGV[0] eq "-plan9") { $plan9 = 1; shift; } if($ARGV[0] eq "-openbsd") { $openbsd = 1; shift; } if($ARGV[0] eq "-netbsd") { $netbsd = 1; shift; } if($ARGV[0] eq "-dragonfly") { $dragonfly = 1; shift; } if($ARGV[0] eq "-arm") { $arm = 1; shift; } if($ARGV[0] =~ /^-/) { print STDERR "usage: mksyscall.pl [-b32 | -l32] [file ...]\n"; exit 1; } if($ENV{'GOARCH'} eq "" || $ENV{'GOOS'} eq "") { print STDERR "GOARCH or GOOS not defined in environment\n"; exit 1; } sub parseparamlist($) { 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); } my $text = ""; while(<>) { chomp; s/\s+/ /g; s/^\s+//; s/\s+$//; my $nonblock = /^\/\/sysnb /; next if !/^\/\/sys / && !$nonblock; # Line must be of the form # func Open(path string, mode int, perm int) (fd int, errno error) # Split into name, in params, out params. if(!/^\/\/sys(nb)? (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*((?i)SYS_[A-Z0-9_]+))?$/) { print STDERR "$ARGV:$.: malformed //sys declaration\n"; $errors = 1; next; } my ($func, $in, $out, $sysname) = ($2, $3, $4, $5); # Split argument lists on comma. my @in = parseparamlist($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; # Check if err return available my $errvar = ""; foreach my $p (@out) { my ($name, $type) = parseparam($p); if($type eq "error") { $errvar = $name; last; } } # Prepare arguments to Syscall. my @args = (); my @uses = (); my $n = 0; foreach my $p (@in) { my ($name, $type) = parseparam($p); if($type =~ /^\*/) { push @args, "uintptr(unsafe.Pointer($name))"; } elsif($type eq "string" && $errvar ne "") { $text .= "\tvar _p$n *byte\n"; $text .= "\t_p$n, $errvar = BytePtrFromString($name)\n"; $text .= "\tif $errvar != nil {\n\t\treturn\n\t}\n"; push @args, "uintptr(unsafe.Pointer(_p$n))"; push @uses, "use(unsafe.Pointer(_p$n))"; $n++; } elsif($type eq "string") { print STDERR "$ARGV:$.: $func uses string arguments, but has no error return\n"; $text .= "\tvar _p$n *byte\n"; $text .= "\t_p$n, _ = BytePtrFromString($name)\n"; push @args, "uintptr(unsafe.Pointer(_p$n))"; push @uses, "use(unsafe.Pointer(_p$n))"; $n++; } elsif($type =~ /^\[\](.*)/) { # Convert slice into pointer, length. # Have to be careful not to take address of &a[0] if len == 0: # pass dummy pointer in that case. # Used to pass nil, but some OSes or simulators reject write(fd, nil, 0). $text .= "\tvar _p$n unsafe.Pointer\n"; $text .= "\tif len($name) > 0 {\n\t\t_p$n = unsafe.Pointer(\&${name}[0])\n\t}"; $text .= " else {\n\t\t_p$n = unsafe.Pointer(&_zero)\n\t}"; $text .= "\n"; push @args, "uintptr(_p$n)", "uintptr(len($name))"; $n++; } elsif($type eq "int64" && ($openbsd || $netbsd)) { push @args, "0"; if($_32bit eq "big-endian") { push @args, "uintptr($name>>32)", "uintptr($name)"; } elsif($_32bit eq "little-endian") { push @args, "uintptr($name)", "uintptr($name>>32)"; } else { push @args, "uintptr($name)"; } } elsif($type eq "int64" && $dragonfly) { if ($func !~ /^extp(read|write)/i) { push @args, "0"; } if($_32bit eq "big-endian") { push @args, "uintptr($name>>32)", "uintptr($name)"; } elsif($_32bit eq "little-endian") { push @args, "uintptr($name)", "uintptr($name>>32)"; } else { push @args, "uintptr($name)"; } } elsif($type eq "int64" && $_32bit ne "") { if(@args % 2 && $arm) { # arm abi specifies 64-bit argument uses # (even, odd) pair push @args, "0" } if($_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 $asm = "Syscall"; if ($nonblock) { $asm = "RawSyscall"; } if(@args <= 3) { while(@args < 3) { push @args, "0"; } } elsif(@args <= 6) { $asm .= "6"; while(@args < 6) { push @args, "0"; } } elsif(@args <= 9) { $asm .= "9"; while(@args < 9) { push @args, "0"; } } else { print STDERR "$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 = ("_", "_", "_"); my $do_errno = 0; for(my $i=0; $i<@out; $i++) { my $p = $out[$i]; my ($name, $type) = parseparam($p); my $reg = ""; if($name eq "err" && !$plan9) { $reg = "e1"; $ret[2] = $reg; $do_errno = 1; } elsif($name eq "err" && $plan9) { $ret[0] = "r0"; $ret[2] = "e1"; next; } 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", $i+1); } if($reg ne "e1" || $plan9) { $body .= "\t$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"; } foreach my $use (@uses) { $text .= "\t$use\n"; } $text .= $body; if ($plan9 && $ret[2] eq "e1") { $text .= "\tif int32(r0) == -1 {\n"; $text .= "\t\terr = e1\n"; $text .= "\t}\n"; } elsif ($do_errno) { $text .= "\tif e1 != 0 {\n"; $text .= "\t\terr = errnoErr(e1)\n"; $text .= "\t}\n"; } $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 // +build $ENV{'GOARCH'},$ENV{'GOOS'} package unix import ( "syscall" "unsafe" ) var _ syscall.Errno $text EOF exit 0;