add os.Hostname

R=r
DELTA=188  (182 added, 3 deleted, 3 changed)
OCL=30856
CL=30860

src/pkg/os/Makefile

@@ -2,8 +2,9 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
+
 # DO NOT EDIT.  Automatically generated by gobuild.
-# gobuild -m dir_${GOOS}_${GOARCH}.go env.go error.go file.go path.go stat_${GOOS}_${GOARCH}.go time.go types.go exec.go proc.go getwd.go >Makefile
+# gobuild -m dir_${GOOS}_${GOARCH}.go env.go error.go file.go path.go stat_${GOOS}_${GOARCH}.go time.go types.go exec.go proc.go getwd.go sys_${GOOS}.go >Makefile
 
 D=
 
@@ -20,7 +21,7 @@ test: packages
 
 coverage: packages
 	gotest
-	6cov -g `pwd` | grep -v '_test\.go:'
+	6cov -g $$(pwd) | grep -v '_test\.go:'
 
 %.$O: %.go
 	$(GC) -I_obj $*.go
@@ -49,6 +50,7 @@ O4=\
 	exec.$O\
 	getwd.$O\
 	path.$O\
+	sys_$(GOOS).$O\
 
 
 phases: a1 a2 a3 a4
@@ -67,7 +69,7 @@ a3: $(O3)
 	rm -f $(O3)
 
 a4: $(O4)
-	$(AR) grc _obj$D/os.a dir_$(GOOS)_$(GOARCH).$O exec.$O getwd.$O path.$O
+	$(AR) grc _obj$D/os.a dir_$(GOOS)_$(GOARCH).$O exec.$O getwd.$O path.$O sys_$(GOOS).$O
 	rm -f $(O4)
 
 

src/pkg/os/os_test.go

@@ -587,3 +587,43 @@ func TestOpenError(t *testing.T) {
 		}
 	}
 }
+
+func run(t *testing.T, cmd []string) string {
+	// Run /bin/hostname and collect output.
+	r, w, err := Pipe();
+	if err != nil {
+		t.Fatal(err);
+	}
+	pid, err := ForkExec("/bin/hostname", []string{"hostname"}, nil, "/", []*File{nil, w, Stderr});
+	if err != nil {
+		t.Fatal(err);
+	}
+	w.Close();
+
+	var b io.ByteBuffer;
+	io.Copy(r, &b);
+	Wait(pid, 0);
+	output := string(b.Data());
+	if n := len(output); n > 0 && output[n-1] == '\n' {
+		output = output[0:n-1];
+	}
+	if output == "" {
+		t.Fatalf("%v produced no output", cmd);
+	}
+
+	return output;
+}
+
+
+func TestHostname(t *testing.T) {
+	// Check internal Hostname() against the output of /bin/hostname.
+	hostname, err := Hostname();
+	if err != nil {
+		t.Fatalf("%v", err);
+	}
+	want := run(t, []string{"/bin/hostname"});
+	if hostname != want {
+		t.Errorf("Hostname() = %q, want %q", hostname, want);
+	}
+}
+

src/pkg/os/sys_darwin.go

@@ -0,0 +1,21 @@
+// 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.
+
+// Darwin-specific
+
+package os
+
+import (
+	"os";
+	"syscall";
+)
+
+func Hostname() (name string, err os.Error) {
+	var errno int;
+	name, errno = syscall.Sysctl("kern.hostname");
+	if errno != 0 {
+		return "", NewSyscallError("sysctl kern.hostname", errno);
+	}
+	return name, nil;
+}

src/pkg/os/sys_linux.go

@@ -0,0 +1,29 @@
+// 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.
+
+// Linux-specific
+
+package os
+
+import "os"
+
+// Hostname returns the host name reported by the kernel.
+func Hostname() (name string, err os.Error) {
+	f, err := Open("/proc/sys/kernel/hostname", O_RDONLY, 0);
+	if err != nil {
+		return "", err;
+	}
+	defer f.Close();
+
+	var buf [512]byte;	// Enough for a DNS name.
+	n, err := f.Read(&buf);
+	if err != nil {
+		return "", err;
+	}
+
+	if n > 0 && buf[n-1] == '\n' {
+		n--;
+	}
+	return string(buf[0:n]), nil;
+}

src/pkg/syscall/syscall_darwin.go

@@ -361,6 +361,82 @@ func Kevent(kq int, changes, events []Kevent_t, timeout *Timespec) (n int, errno
 	return kevent(kq, change, len(changes), event, len(events), timeout);
 }
 
+//sys	sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (errno int) = SYS___SYSCTL
+
+// Translate "kern.hostname" to []_C_int{0,1,2,3}.
+func nametomib(name string) (mib []_C_int, errno int) {
+	const CTL_MAXNAME = 12;
+	const siz = uintptr(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 errno = sysctl([]_C_int{0, 3}, p, &n, &bytes[0], uintptr(len(name))); errno != 0 {
+		return nil, errno;
+	}
+	return buf[0:n/siz], 0;
+}
+
+func Sysctl(name string) (value string, errno int) {
+	// Translate name to mib number.
+	mib, errno := nametomib(name);
+	if errno != 0 {
+		return "", errno;
+	}
+
+	// Find size.
+	n := uintptr(0);
+	if errno = sysctl(mib, nil, &n, nil, 0); errno != 0 {
+		return "", errno;
+	}
+	if n == 0 {
+		return "", 0;
+	}
+
+	// Read into buffer of that size.
+	buf := make([]byte, n);
+	if errno = sysctl(mib, &buf[0], &n, nil, 0); errno != 0 {
+		return "", errno;
+	}
+
+	// Throw away terminating NUL.
+	if n > 0 && buf[n-1] == '\x00' {
+		n--;
+	}
+	return string(buf[0:n]), 0;
+}
+
+func SysctlUint32(name string) (value uint32, errno int) {
+	// Translate name to mib number.
+	mib, errno := nametomib(name);
+	if errno != 0 {
+		return 0, errno;
+	}
+
+	// Read into buffer of that size.
+	n := uintptr(4);
+	buf := make([]byte, 4);
+	if errno = sysctl(mib, &buf[0], &n, nil, 0); errno != 0 {
+		return 0, errno;
+	}
+	if n != 4 {
+		return 0, EIO;
+	}
+	return *(*uint32)(unsafe.Pointer(&buf[0])), 0;
+}
+
 // TODO: wrap
 //	Acct(name nil-string) (errno int)
 //	Futimes(fd int, timeval *Timeval) (errno int)	// Pointer to 2 timevals!
@@ -500,7 +576,6 @@ func Kevent(kq int, changes, events []Kevent_t, timeout *Timespec) (n int, errno
 // Kdebug_trace
 // Sigreturn
 // Mmap
-// __Sysctl
 // Mlock
 // Munlock
 // Atsocket

src/pkg/syscall/syscall_linux.go

@@ -383,8 +383,6 @@ func SetsockoptLinger(fd, level, opt int, l *Linger) (errno int) {
 // Recvfrom
 // Sendmsg
 // Recvmsg
-// Getsockname
-// Getpeername
 // Socketpair
 // Getsockopt
 

src/pkg/syscall/zsyscall_darwin_386.go

@@ -87,6 +87,14 @@ func kevent(kq int, change uintptr, nchange int, event uintptr, nevent int, time
 	return;
 }
 
+func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (errno int) {
+	var _p0 *_C_int;
+	if len(mib) > 0 { _p0 = &mib[0]; }
+	r0, r1, e1 := Syscall6(SYS___SYSCTL, uintptr(unsafe.Pointer(_p0)), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen));
+	errno = int(e1);
+	return;
+}
+
 func fcntl(fd int, cmd int, arg int) (val int, errno int) {
 	r0, r1, e1 := Syscall(SYS_FCNTL, uintptr(fd), uintptr(cmd), uintptr(arg));
 	val = int(r0);

src/pkg/syscall/zsyscall_darwin_amd64.go

@@ -87,6 +87,14 @@ func kevent(kq int, change uintptr, nchange int, event uintptr, nevent int, time
 	return;
 }
 
+func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (errno int) {
+	var _p0 *_C_int;
+	if len(mib) > 0 { _p0 = &mib[0]; }
+	r0, r1, e1 := Syscall6(SYS___SYSCTL, uintptr(unsafe.Pointer(_p0)), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen));
+	errno = int(e1);
+	return;
+}
+
 func fcntl(fd int, cmd int, arg int) (val int, errno int) {
 	r0, r1, e1 := Syscall(SYS_FCNTL, uintptr(fd), uintptr(cmd), uintptr(arg));
 	val = int(r0);