syscall: implement nametomib() on netbsd

Implement nametomib() on NetBSD using the CTL_QUERY node discovery
mechanism.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6211071

src/pkg/syscall/mkerrors.sh

@@ -106,7 +106,7 @@ includes_NetBSD='
 #include <netinet/if_ether.h>
 
 // Needed since <sys/param.h> refers to it...
-const int schedppq = 1;
+#define schedppq 1
 '
 
 includes_OpenBSD='
@@ -199,8 +199,8 @@ ccflags="$@"
 		$2 == "SOMAXCONN" ||
 		$2 == "NAME_MAX" ||
 		$2 == "IFNAMSIZ" ||
-		$2 == "CTL_NET" ||
+		$2 ~ /^CTL_(MAXNAME|NET|QUERY)$/ ||
-		$2 == "CTL_MAXNAME" ||
+		$2 ~ /^SYSCTL_VERS/ ||
 		$2 ~ /^(MS|MNT)_/ ||
 		$2 ~ /^TUN(SET|GET|ATTACH|DETACH)/ ||
 		$2 ~ /^(O|F|FD|NAME|S|PTRACE|PT)_/ ||

src/pkg/syscall/syscall_netbsd.go

@@ -28,8 +28,66 @@ type SockaddrDatalink struct {
 
 func Syscall9(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno)
 
+func sysctlNodes(mib []_C_int) (nodes []Sysctlnode, err error) {
+	var olen uintptr
+
+	// Get a list of all sysctl nodes below the given MIB by performing
+	// a sysctl for the given MIB with CTL_QUERY appended.
+	mib = append(mib, CTL_QUERY)
+	qnode := Sysctlnode{Flags: SYSCTL_VERS_1}
+	qp := (*byte)(unsafe.Pointer(&qnode))
+	sz := unsafe.Sizeof(qnode)
+	if err = sysctl(mib, nil, &olen, qp, sz); err != nil {
+		return nil, err
+	}
+
+	// Now that we know the size, get the actual nodes.
+	nodes = make([]Sysctlnode, olen/sz)
+	np := (*byte)(unsafe.Pointer(&nodes[0]))
+	if err = sysctl(mib, np, &olen, qp, sz); err != nil {
+		return nil, err
+	}
+
+	return nodes, nil
+}
+
 func nametomib(name string) (mib []_C_int, err error) {
+
+	// Split name into components.
+	var parts []string
+	last := 0
+	for i := 0; i < len(name); i++ {
+		if name[i] == '.' {
+			parts = append(parts, name[last:i])
+			last = i + 1
+		}
+	}
+	parts = append(parts, name[last:])
+
+	// Discover the nodes and construct the MIB OID.
+	for partno, part := range parts {
+		nodes, err := sysctlNodes(mib)
+		if err != nil {
+			return nil, err
+		}
+		for _, node := range nodes {
+			n := make([]byte, 0)
+			for i := range node.Name {
+				if node.Name[i] != 0 {
+					n = append(n, byte(node.Name[i]))
+				}
+			}
+			if string(n) == part {
+				mib = append(mib, _C_int(node.Num))
+				break
+			}
+		}
+		if len(mib) != partno+1 {
 			return nil, EINVAL
+		}
+	}
+
+	return mib, nil
 }
 
 // ParseDirent parses up to max directory entries in buf,

src/pkg/syscall/types_netbsd.go

@@ -31,6 +31,7 @@ package syscall
 #include <sys/signal.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
+#include <sys/sysctl.h>
 #include <sys/time.h>
 #include <sys/uio.h>
 #include <sys/un.h>
@@ -210,3 +211,7 @@ type BpfInsn C.struct_bpf_insn
 type BpfHdr C.struct_bpf_hdr
 
 type BpfTimeval C.struct_bpf_timeval
+
+// Sysctl
+
+type Sysctlnode C.struct_sysctlnode

src/pkg/syscall/zerrors_netbsd_386.go

@@ -159,6 +159,7 @@ const (
 	CSUSP                             = 0x1a
 	CTL_MAXNAME                       = 0xc
 	CTL_NET                           = 0x4
+	CTL_QUERY                         = -0x2
 	DIOCBSFLUSH                       = 0x20006478
 	DLT_AIRONET_HEADER                = 0x78
 	DLT_APPLE_IP_OVER_IEEE1394        = 0x8a
@@ -984,6 +985,7 @@ const (
 	PARMRK                            = 0x8
 	PARODD                            = 0x2000
 	PENDIN                            = 0x20000000
+	PRI_IOFLUSH                       = 0x7c
 	RLIMIT_AS                         = 0xa
 	RLIMIT_CORE                       = 0x4
 	RLIMIT_CPU                        = 0x0
@@ -1163,6 +1165,10 @@ const (
 	SO_TIMESTAMP                      = 0x2000
 	SO_TYPE                           = 0x1008
 	SO_USELOOPBACK                    = 0x40
+	SYSCTL_VERSION                    = 0x1000000
+	SYSCTL_VERS_0                     = 0x0
+	SYSCTL_VERS_1                     = 0x1000000
+	SYSCTL_VERS_MASK                  = 0xff000000
 	S_ARCH1                           = 0x10000
 	S_ARCH2                           = 0x20000
 	S_BLKSIZE                         = 0x200

src/pkg/syscall/zerrors_netbsd_amd64.go

@@ -159,6 +159,7 @@ const (
 	CSUSP                             = 0x1a
 	CTL_MAXNAME                       = 0xc
 	CTL_NET                           = 0x4
+	CTL_QUERY                         = -0x2
 	DIOCBSFLUSH                       = 0x20006478
 	DLT_AIRONET_HEADER                = 0x78
 	DLT_APPLE_IP_OVER_IEEE1394        = 0x8a
@@ -974,6 +975,7 @@ const (
 	PARMRK                            = 0x8
 	PARODD                            = 0x2000
 	PENDIN                            = 0x20000000
+	PRI_IOFLUSH                       = 0x7c
 	RLIMIT_AS                         = 0xa
 	RLIMIT_CORE                       = 0x4
 	RLIMIT_CPU                        = 0x0
@@ -1153,6 +1155,10 @@ const (
 	SO_TIMESTAMP                      = 0x2000
 	SO_TYPE                           = 0x1008
 	SO_USELOOPBACK                    = 0x40
+	SYSCTL_VERSION                    = 0x1000000
+	SYSCTL_VERS_0                     = 0x0
+	SYSCTL_VERS_1                     = 0x1000000
+	SYSCTL_VERS_MASK                  = 0xff000000
 	S_ARCH1                           = 0x10000
 	S_ARCH2                           = 0x20000
 	S_BLKSIZE                         = 0x200

src/pkg/syscall/ztypes_netbsd_386.go

@@ -348,3 +348,16 @@ type BpfTimeval struct {
 	Sec  int32
 	Usec int32
 }
+
+type Sysctlnode struct {
+	Flags           uint32
+	Num             int32
+	Name            [32]int8
+	Ver             uint32
+	X__rsvd         uint32
+	Un              [16]byte
+	X_sysctl_size   [8]byte
+	X_sysctl_func   [8]byte
+	X_sysctl_parent [8]byte
+	X_sysctl_desc   [8]byte
+}

src/pkg/syscall/ztypes_netbsd_amd64.go

@@ -355,3 +355,16 @@ type BpfTimeval struct {
 	Sec  int64
 	Usec int64
 }
+
+type Sysctlnode struct {
+	Flags           uint32
+	Num             int32
+	Name            [32]int8
+	Ver             uint32
+	X__rsvd         uint32
+	Un              [16]byte
+	X_sysctl_size   [8]byte
+	X_sysctl_func   [8]byte
+	X_sysctl_parent [8]byte
+	X_sysctl_desc   [8]byte
+}