diff options
Diffstat (limited to 'src/syscall/mksyscall.pl')
| -rwxr-xr-x | src/syscall/mksyscall.pl | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/src/syscall/mksyscall.pl b/src/syscall/mksyscall.pl new file mode 100755 index 0000000..25ab911 --- /dev/null +++ b/src/syscall/mksyscall.pl @@ -0,0 +1,398 @@ +#!/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 $darwin = 0; +my $openbsd = 0; +my $netbsd = 0; +my $dragonfly = 0; +my $arm = 0; # 64-bit value should use (even, odd)-pair +my $libc = 0; +my $tags = ""; # build tags +my $newtags = ""; # new style build tags +my $extraimports = ""; + +if($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 "-darwin") { + $darwin = 1; + $libc = 1; + shift; +} +if($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] eq "-libc") { + $libc = 1; + shift; +} +if($ARGV[0] eq "-tags") { + shift; + $tags = $ARGV[0]; + shift; +} + +if($ARGV[0] =~ /^-/) { + print STDERR "usage: mksyscall.pl [-b32 | -l32] [-tags x,y] [file ...]\n"; + exit 1; +} + +if($libc) { + $extraimports = 'import "internal/abi"'; +} + +sub parseparamlist($) { + 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); +} + +# set of trampolines we've already generated +my %trampolines; + +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. + $text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n"; + + if (($darwin && $func eq "ptrace1") || (($openbsd && $libc) && $func eq "ptrace")) { + # The ptrace function is called from forkAndExecInChild where stack + # growth is forbidden. + $text .= "//go:nosplit\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 $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))"; + $n++; + } elsif($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))"; + $n++; + } elsif($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 || $netbsd)) { + if (!$libc) { + push @args, "0"; + } + if($libc && $arm && @args % 2) { + # arm abi specifies 64 bit argument must be 64 bit aligned. + push @args, "0" + } + if($_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) { + if ($errvar eq "" && $ENV{'GOOS'} eq "linux") { + $asm = "rawSyscallNoError"; + } else { + $asm = "RawSyscall"; + } + } + if ($libc) { + # Call unexported syscall functions (which take + # libc functions instead of syscall numbers). + $asm = lcfirst($asm); + } + 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:$.: too many arguments to system call\n"; + } + + if ($darwin || ($openbsd && $libc)) { + # Use extended versions for calls that generate a 64-bit result. + my ($name, $type) = parseparam($out[0]); + if ($type eq "int64" || ($type eq "uintptr" && $_32bit eq "")) { + $asm .= "X"; + } + } + + # System call number. + my $funcname = ""; + if($sysname eq "") { + $sysname = "SYS_$func"; + $sysname =~ s/([a-z])([A-Z])/${1}_$2/g; # turn FooBar into Foo_Bar + $sysname =~ y/a-z/A-Z/; + if($libc) { + $sysname =~ y/A-Z/a-z/; + $sysname = substr $sysname, 4; + $funcname = "libc_$sysname"; + } + } + if($libc) { + if($funcname eq "") { + $sysname = substr $sysname, 4; + $funcname = "libc_$sysname"; + } + $sysname = "abi.FuncPCABI0(${funcname}_trampoline)"; + } + + # 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 { + if ($errvar eq "" && $ENV{'GOOS'} eq "linux") { + # raw syscall without error on Linux, see golang.org/issue/22924 + $text .= "\t$ret[0], $ret[1] := $call\n"; + } else { + $text .= "\t$ret[0], $ret[1], $ret[2] := $call\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"; + $text .= "}\n\n"; + if($libc) { + if (not exists $trampolines{$funcname}) { + $trampolines{$funcname} = 1; + # The assembly trampoline that jumps to the libc routine. + $text .= "func ${funcname}_trampoline()\n\n"; + # Tell the linker that funcname can be found in libSystem using varname without the libc_ prefix. + my $basename = substr $funcname, 5; + my $libc = "libc.so"; + if ($darwin) { + $libc = "/usr/lib/libSystem.B.dylib"; + } + $text .= "//go:cgo_import_dynamic $funcname $basename \"$libc\"\n\n"; + } + } +} + +chomp $text; +chomp $text; + +if($errors) { + exit 1; +} + +# TODO: this assumes tags are just simply comma separated. For now this is all the uses. +$newtags = $tags =~ s/,/ && /r; + +print <<EOF; +// $cmdline +// Code generated by the command above; DO NOT EDIT. + +//go:build $newtags + +package syscall + +import "unsafe" +$extraimports + +$text +EOF +exit 0; |