syscall: implement nametomib for openbsd.

Move the existing darwin/freebsd specific nametomib implementation
into the respective operating system dependent files.

Provide a nametomib implementation for openbsd, which operates on a
sysctl MIB that has been pre-generated from the various system headers
by mksysctl_openbsd.pl.

R=rsc
CC=golang-dev
https://golang.org/cl/4935044

src/pkg/syscall/Makefile

@@ -54,6 +54,7 @@ GOFILES_openbsd=\
 	sockcmsg_unix.go\
 	syscall_bsd.go\
 	syscall_unix.go\
+	zsysctl_openbsd.go\
 
 GOFILES_windows=\
 	env_windows.go\

src/pkg/syscall/mkall.sh

@@ -79,6 +79,8 @@ GOOSARCH="${GOOS}_${GOARCH}"
 mksyscall="./mksyscall.pl"
 mkerrors="./mkerrors.sh"
 zerrors="zerrors_$GOOSARCH.go"
+mksysctl=""
+zsysctl="zsysctl_$GOOSARCH.go"
 run="sh"
 
 case "$1" in
@@ -169,12 +171,16 @@ plan9_386)
 openbsd_386)
 	mkerrors="$mkerrors -m32"
 	mksyscall="./mksyscall.pl -l32 -openbsd"
+	mksysctl="./mksysctl_openbsd.pl"
+	zsysctl="zsysctl_openbsd.go"
 	mksysnum="curl -s 'http://www.openbsd.org/cgi-bin/cvsweb/~checkout~/src/sys/kern/syscalls.master' | ./mksysnum_openbsd.pl"
 	mktypes="GOARCH=$GOARCH cgo -godefs"
 	;;
 openbsd_amd64)
 	mkerrors="$mkerrors -m64"
 	mksyscall="./mksyscall.pl -openbsd"
+	mksysctl="./mksysctl_openbsd.pl"
+	zsysctl="zsysctl_openbsd.go"
 	mksysnum="curl -s 'http://www.openbsd.org/cgi-bin/cvsweb/~checkout~/src/sys/kern/syscalls.master' | ./mksysnum_openbsd.pl"
 	mktypes="GOARCH=$GOARCH cgo -godefs"
 	;;
@@ -192,6 +198,7 @@ esac
 		syscall_goos="syscall_bsd.go $syscall_goos"
 		;;
 	esac
+	if [ -n "$mksysctl" ]; then echo "$mksysctl |gofmt >$zsysctl"; fi
 	if [ -n "$mksyscall" ]; then echo "$mksyscall $syscall_goos syscall_$GOOSARCH.go |gofmt >zsyscall_$GOOSARCH.go"; fi
 	if [ -n "$mksysnum" ]; then echo "$mksysnum |gofmt >zsysnum_$GOOSARCH.go"; fi
 	if [ -n "$mktypes" ]; then echo "$mktypes types_$GOOS.go |gofmt >ztypes_$GOOSARCH.go"; fi

src/pkg/syscall/mksysctl_openbsd.pl

+#!/usr/bin/perl
+
+# Copyright 2011 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.
+
+#
+# Parse the header files for OpenBSD and generate a Go usable sysctl MIB.
+#
+# Build a MIB with each entry being an array containing the level, type and
+# a hash that will contain additional entries if the current entry is a node.
+# We then walk this MIB and create a flattened sysctl name to OID hash.
+#
+
+use strict;
+
+my $debug = 0;
+my %ctls = ();
+
+my @headers = qw (
+	sys/sysctl.h
+	sys/socket.h
+	sys/tty.h
+	sys/malloc.h
+	sys/mount.h
+	sys/namei.h
+	sys/sem.h
+	sys/shm.h
+	sys/vmmeter.h
+	uvm/uvm_param.h
+	uvm/uvm_swap_encrypt.h
+	ddb/db_var.h
+	net/if.h
+	net/if_pfsync.h
+	net/pipex.h
+	netinet/in.h
+	netinet/icmp_var.h
+	netinet/igmp_var.h
+	netinet/ip_ah.h
+	netinet/ip_carp.h
+	netinet/ip_divert.h
+	netinet/ip_esp.h
+	netinet/ip_ether.h
+	netinet/ip_gre.h
+	netinet/ip_ipcomp.h
+	netinet/ip_ipip.h
+	netinet/pim_var.h
+	netinet/tcp_var.h
+	netinet/udp_var.h
+	netinet6/in6.h
+	netinet6/ip6_divert.h
+	netinet6/pim6_var.h
+	netinet/icmp6.h
+	netmpls/mpls.h
+);
+
+my @ctls = qw (
+	kern
+	vm
+	fs
+	net
+	#debug				# Special handling required
+	hw
+	#machdep			# Arch specific
+	user
+	ddb
+	#vfs				# Special handling required
+	fs.posix
+	kern.forkstat
+	kern.intrcnt
+	kern.malloc
+	kern.nchstats
+	kern.seminfo
+	kern.shminfo
+	kern.timecounter
+	kern.tty
+	kern.watchdog
+	net.bpf
+	net.ifq
+	net.inet
+	net.inet.ah
+	net.inet.carp
+	net.inet.divert
+	net.inet.esp
+	net.inet.etherip
+	net.inet.gre
+	net.inet.icmp
+	net.inet.igmp
+	net.inet.ip
+	net.inet.ip.ifq
+	net.inet.ipcomp
+	net.inet.ipip
+	net.inet.mobileip
+	net.inet.pfsync
+	net.inet.pim
+	net.inet.tcp
+	net.inet.udp
+	net.inet6
+	net.inet6.divert
+	net.inet6.ip6
+	net.inet6.icmp6
+	net.inet6.pim6
+	net.inet6.tcp6
+	net.inet6.udp6
+	net.mpls
+	net.mpls.ifq
+	net.key
+	net.pflow
+	net.pfsync
+	net.pipex
+	net.rt
+	vm.swapencrypt
+	#vfsgenctl			# Special handling required
+);
+
+# Node name "fixups"
+my %ctl_map = (
+	"ipproto" => "net.inet",
+	"net.inet.ipproto" => "net.inet",
+	"net.inet6.ipv6proto" => "net.inet6",
+	"net.inet6.ipv6" => "net.inet6.ip6",
+	"net.inet.icmpv6" => "net.inet6.icmp6",
+	"net.inet6.divert6" => "net.inet6.divert",
+	"net.inet6.tcp6" => "net.inet.tcp",
+	"net.inet6.udp6" => "net.inet.udp",
+	"mpls" => "net.mpls",
+	"swpenc" => "vm.swapencrypt"
+);
+
+# Node mappings
+my %node_map = (
+	"net.inet.ip.ifq" => "net.ifq",
+	"net.inet.pfsync" => "net.pfsync",
+	"net.mpls.ifq" => "net.ifq"
+);
+
+my $ctlname;
+my %mib = ();
+my %sysctl = ();
+my $node;
+
+sub debug() {
+	print STDERR "$_[0]\n" if $debug;
+}
+
+# Walk the MIB and build a sysctl name to OID mapping.
+sub build_sysctl() {
+	my ($node, $name, $oid) = @_;
+	my %node = %{$node};
+	my @oid = @{$oid};
+
+	foreach my $key (sort keys %node) {
+		my @node = @{$node{$key}};
+		my $nodename = $name.($name ne '' ? '.' : '').$key;
+		my @nodeoid = (@oid, $node[0]);
+		if ($node[1] eq 'CTLTYPE_NODE') {
+			if (exists $node_map{$nodename}) {
+				$node = \%mib;
+				$ctlname = $node_map{$nodename};
+				foreach my $part (split /\./, $ctlname) {
+					$node = \%{@{$$node{$part}}[2]};
+				}
+			} else {
+				$node = $node[2];
+			}
+			&build_sysctl($node, $nodename, \@nodeoid);
+		} elsif ($node[1] ne '') {
+			$sysctl{$nodename} = \@nodeoid;
+		}
+	}
+}
+
+foreach my $ctl (@ctls) {
+	$ctls{$ctl} = $ctl;
+}
+
+# Build MIB
+foreach my $header (@headers) {
+	&debug("Processing $header...");
+	open HEADER, "/usr/include/$header" ||
+	    print STDERR "Failed to open $header\n";
+	while (<HEADER>) {
+		if ($_ =~ /^#define\s+(CTL_NAMES)\s+{/ ||
+		    $_ =~ /^#define\s+(CTL_(.*)_NAMES)\s+{/ ||
+		    $_ =~ /^#define\s+((.*)CTL_NAMES)\s+{/) {
+			if ($1 eq 'CTL_NAMES') {
+				# Top level.
+				$node = \%mib;
+			} else {
+				# Node.
+				my $nodename = lc($2);
+				if ($header =~ /^netinet\//) {
+					$ctlname = "net.inet.$nodename";
+				} elsif ($header =~ /^netinet6\//) {
+					$ctlname = "net.inet6.$nodename";
+				} elsif ($header =~ /^net\//) {
+					$ctlname = "net.$nodename";
+				} else {
+					$ctlname = "$nodename";
+					$ctlname =~ s/^(fs|net|kern)_/$1\./;
+				}
+				if (exists $ctl_map{$ctlname}) {
+					$ctlname = $ctl_map{$ctlname};
+				}
+				if (not exists $ctls{$ctlname}) {
+					&debug("Ignoring $ctlname...");
+					next;
+				}
+
+				# Walk down from the top of the MIB.
+				$node = \%mib;
+				foreach my $part (split /\./, $ctlname) {
+					if (not exists $$node{$part}) {
+						&debug("Missing node $part");
+						$$node{$part} = [ 0, '', {} ];
+					}
+					$node = \%{@{$$node{$part}}[2]};
+				}
+			}
+
+			# Populate current node with entries.
+			my $i = -1;
+			while (defined($_) && $_ !~ /^}/) {
+				$_ = <HEADER>;
+				$i++ if $_ =~ /{.*}/;
+				next if $_ !~ /{\s+"(\w+)",\s+(CTLTYPE_[A-Z]+)\s+}/;
+				$$node{$1} = [ $i, $2, {} ];
+			}
+		}
+	}
+	close HEADER;
+}
+
+&build_sysctl(\%mib, "", []);
+
+print <<EOF;
+// mksysctl_openbsd.pl
+// MACHINE GENERATED BY THE ABOVE COMMAND; DO NOT EDIT
+
+package syscall;
+
+type mibentry struct {
+	ctlname string
+	ctloid []_C_int
+}
+
+var sysctlMib = []mibentry {
+EOF
+
+foreach my $name (sort keys %sysctl) {
+	my @oid = @{$sysctl{$name}};
+	print "\t{ \"$name\", []_C_int{ ", join(', ', @oid), " } }, \n";
+}
+
+print <<EOF;
+}
+EOF

src/pkg/syscall/syscall_bsd.go

@@ -546,31 +546,6 @@ func Kevent(kq int, changes, events []Kevent_t, timeout *Timespec) (n int, err e
 
 //sys	sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) = SYS___SYSCTL
 
-// Translate "kern.hostname" to []_C_int{0,1,2,3}.
-func nametomib(name string) (mib []_C_int, err error) {
-	const siz = unsafe.Sizeof(mib[0])
-
-	// NOTE(rsc): It seems strange to set the buffer to have
-	// size CTL_MAXNAME+2 but use only CTL_MAXNAME
-	// as the size.  I don't know why the +2 is here, but the
-	// kernel uses +2 for its own implementation of this function.
-	// I am scared that if we don't include the +2 here, the kernel
-	// will silently write 2 words farther than we specify
-	// and we'll get memory corruption.
-	var buf [CTL_MAXNAME + 2]_C_int
-	n := uintptr(CTL_MAXNAME) * siz
-
-	p := (*byte)(unsafe.Pointer(&buf[0]))
-	bytes := StringByteSlice(name)
-
-	// Magic sysctl: "setting" 0.3 to a string name
-	// lets you read back the array of integers form.
-	if err = sysctl([]_C_int{0, 3}, p, &n, &bytes[0], uintptr(len(name))); err != nil {
-		return nil, err
-	}
-	return buf[0 : n/siz], nil
-}
-
 func Sysctl(name string) (value string, err error) {
 	// Translate name to mib number.
 	mib, err := nametomib(name)

src/pkg/syscall/syscall_darwin.go

@@ -28,6 +28,31 @@ type SockaddrDatalink struct {
 	raw    RawSockaddrDatalink
 }
 
+// Translate "kern.hostname" to []_C_int{0,1,2,3}.
+func nametomib(name string) (mib []_C_int, err error) {
+	const siz = unsafe.Sizeof(mib[0])
+
+	// NOTE(rsc): It seems strange to set the buffer to have
+	// size CTL_MAXNAME+2 but use only CTL_MAXNAME
+	// as the size.  I don't know why the +2 is here, but the
+	// kernel uses +2 for its own implementation of this function.
+	// I am scared that if we don't include the +2 here, the kernel
+	// will silently write 2 words farther than we specify
+	// and we'll get memory corruption.
+	var buf [CTL_MAXNAME + 2]_C_int
+	n := uintptr(CTL_MAXNAME) * siz
+
+	p := (*byte)(unsafe.Pointer(&buf[0]))
+	bytes := StringByteSlice(name)
+
+	// Magic sysctl: "setting" 0.3 to a string name
+	// lets you read back the array of integers form.
+	if err = sysctl([]_C_int{0, 3}, p, &n, &bytes[0], uintptr(len(name))); err != nil {
+		return nil, err
+	}
+	return buf[0 : n/siz], nil
+}
+
 // ParseDirent parses up to max directory entries in buf,
 // appending the names to names.  It returns the number
 // bytes consumed from buf, the number of entries added

src/pkg/syscall/syscall_freebsd.go

@@ -28,6 +28,31 @@ type SockaddrDatalink struct {
 	raw    RawSockaddrDatalink
 }
 
+// Translate "kern.hostname" to []_C_int{0,1,2,3}.
+func nametomib(name string) (mib []_C_int, err error) {
+	const siz = unsafe.Sizeof(mib[0])
+
+	// NOTE(rsc): It seems strange to set the buffer to have
+	// size CTL_MAXNAME+2 but use only CTL_MAXNAME
+	// as the size.  I don't know why the +2 is here, but the
+	// kernel uses +2 for its own implementation of this function.
+	// I am scared that if we don't include the +2 here, the kernel
+	// will silently write 2 words farther than we specify
+	// and we'll get memory corruption.
+	var buf [CTL_MAXNAME + 2]_C_int
+	n := uintptr(CTL_MAXNAME) * siz
+
+	p := (*byte)(unsafe.Pointer(&buf[0]))
+	bytes := StringByteSlice(name)
+
+	// Magic sysctl: "setting" 0.3 to a string name
+	// lets you read back the array of integers form.
+	if err = sysctl([]_C_int{0, 3}, p, &n, &bytes[0], uintptr(len(name))); err != nil {
+		return nil, err
+	}
+	return buf[0 : n/siz], nil
+}
+
 // ParseDirent parses up to max directory entries in buf,
 // appending the names to names.  It returns the number
 // bytes consumed from buf, the number of entries added

src/pkg/syscall/syscall_openbsd.go

@@ -30,6 +30,28 @@ type SockaddrDatalink struct {
 
 func Syscall9(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno)
 
+func nametomib(name string) (mib []_C_int, err error) {
+
+	// Perform lookup via a binary search
+	left := 0
+	right := len(sysctlMib) - 1
+	for {
+		idx := left + (right-left)/2
+		switch {
+		case name == sysctlMib[idx].ctlname:
+			return sysctlMib[idx].ctloid, nil
+		case name > sysctlMib[idx].ctlname:
+			left = idx + 1
+		default:
+			right = idx - 1
+		}
+		if left > right {
+			break
+		}
+	}
+	return nil, EINVAL
+}
+
 // ParseDirent parses up to max directory entries in buf,
 // appending the names to names. It returns the number
 // bytes consumed from buf, the number of entries added