| #!/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 $tags = ""; # build tags |
| |
| if($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; |
| } |
| |
| 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 || ($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($_32bit eq "big-endian") { |
| push @args, "uintptr($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"; |
| } |
| $sysname = "funcPC(${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"; |
| # Map syscall.funcname to just plain funcname. |
| # (The jump to this function is in the assembly trampoline, generated by mkasm.go.) |
| $text .= "//go:linkname $funcname $funcname\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; |
| } |
| |
| print <<EOF; |
| // $cmdline |
| // Code generated by the command above; DO NOT EDIT. |
| |
| // +build $tags |
| |
| package syscall |
| |
| import "unsafe" |
| |
| $text |
| EOF |
| exit 0; |