libgo: Update to revision 15193:6fdc1974457c of master library.

From-SVN: r194692

4 files changed, 85 insertions, 17 deletions

diff --git a/libgo/go/syscall/env_plan9.go b/libgo/go/syscall/env_plan9.go
index 2848d9b..0f89aa9 100644
--- a/libgo/go/syscall/env_plan9.go
+++ b/libgo/go/syscall/env_plan9.go
@@ -12,14 +12,17 @@ import (
 )
 
 var (
-	// envOnce guards initialization by copyenv, which populates env.
+	// envOnce guards copyenv, which populates env.
 	envOnce sync.Once
 
 	// envLock guards env.
 	envLock sync.RWMutex
 
 	// env maps from an environment variable to its value.
-	env map[string]string
+	env = make(map[string]string)
+
+	errZeroLengthKey = errors.New("zero length key")
+	errShortWrite    = errors.New("i/o count too small")
 )
 
 func readenv(key string) (string, error) {
@@ -47,12 +50,18 @@ func writeenv(key, value string) error {
 		return err
 	}
 	defer Close(fd)
-	_, err = Write(fd, []byte(value))
-	return err
+	b := []byte(value)
+	n, err := Write(fd, b)
+	if err != nil {
+		return err
+	}
+	if n != len(b) {
+		return errShortWrite
+	}
+	return nil
 }
 
 func copyenv() {
-	env = make(map[string]string)
 	fd, err := Open("/env", O_RDONLY)
 	if err != nil {
 		return
@@ -72,7 +81,6 @@ func copyenv() {
 }
 
 func Getenv(key string) (value string, found bool) {
-	envOnce.Do(copyenv)
 	if len(key) == 0 {
 		return "", false
 	}
@@ -80,17 +88,20 @@ func Getenv(key string) (value string, found bool) {
 	envLock.RLock()
 	defer envLock.RUnlock()
 
-	v, ok := env[key]
-	if !ok {
+	if v, ok := env[key]; ok {
+		return v, true
+	}
+	v, err := readenv(key)
+	if err != nil {
 		return "", false
 	}
+	env[key] = v
 	return v, true
 }
 
 func Setenv(key, value string) error {
-	envOnce.Do(copyenv)
 	if len(key) == 0 {
-		return errors.New("zero length key")
+		return errZeroLengthKey
 	}
 
 	envLock.Lock()
@@ -105,8 +116,6 @@ func Setenv(key, value string) error {
 }
 
 func Clearenv() {
-	envOnce.Do(copyenv) // prevent copyenv in Getenv/Setenv
-
 	envLock.Lock()
 	defer envLock.Unlock()
 
@@ -115,9 +124,10 @@ func Clearenv() {
 }
 
 func Environ() []string {
-	envOnce.Do(copyenv)
 	envLock.RLock()
 	defer envLock.RUnlock()
+
+	envOnce.Do(copyenv)
 	a := make([]string, len(env))
 	i := 0
 	for k, v := range env {
diff --git a/libgo/go/syscall/libcall_linux_utimesnano.go b/libgo/go/syscall/libcall_linux_utimesnano.go
new file mode 100644
index 0000000..043ab0d
--- /dev/null
+++ b/libgo/go/syscall/libcall_linux_utimesnano.go
@@ -0,0 +1,29 @@
+// Copyright 2012 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.
+
+// GNU/Linux version of UtimesNano.
+
+package syscall
+
+import "unsafe"
+
+//sys	utimensat(dirfd int, path string, times *[2]Timespec, flags int) (err error)
+//utimensat(dirfd int, path *byte, times *[2]Timespec, flags int) int
+func UtimesNano(path string, ts []Timespec) (err error) {
+	if len(ts) != 2 {
+		return EINVAL
+	}
+	err = utimensat(_AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0)
+	if err != ENOSYS {
+		return err
+	}
+	// If the utimensat syscall isn't available (utimensat was added to Linux
+	// in 2.6.22, Released, 8 July 2007) then fall back to utimes
+	var tv [2]Timeval
+	for i := 0; i < 2; i++ {
+		tv[i].Sec = Timeval_sec_t(ts[i].Sec)
+		tv[i].Usec = Timeval_usec_t(ts[i].Nsec / 1000)
+	}
+	return utimes(path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
+}
diff --git a/libgo/go/syscall/libcall_posix_utimesnano.go b/libgo/go/syscall/libcall_posix_utimesnano.go
new file mode 100644
index 0000000..e0751f5
--- /dev/null
+++ b/libgo/go/syscall/libcall_posix_utimesnano.go
@@ -0,0 +1,24 @@
+// Copyright 2012 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.
+
+// General POSIX version of UtimesNano.
+
+package syscall
+
+import "unsafe"
+
+func UtimesNano(path string, ts []Timespec) error {
+	// TODO: The BSDs can do utimensat with SYS_UTIMENSAT but it
+	// isn't supported by darwin so this uses utimes instead
+	if len(ts) != 2 {
+		return EINVAL
+	}
+	// Not as efficient as it could be because Timespec and
+	// Timeval have different types in the different OSes
+	tv := [2]Timeval{
+		NsecToTimeval(TimespecToNsec(ts[0])),
+		NsecToTimeval(TimespecToNsec(ts[1])),
+	}
+	return utimes(path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
+}
diff --git a/libgo/go/syscall/syscall.go b/libgo/go/syscall/syscall.go
index 56296c8..c4f2125 100644
--- a/libgo/go/syscall/syscall.go
+++ b/libgo/go/syscall/syscall.go
@@ -3,10 +3,15 @@
 // license that can be found in the LICENSE file.
 
 // Package syscall contains an interface to the low-level operating system
-// primitives.  The details vary depending on the underlying system.
-// Its primary use is inside other packages that provide a more portable
-// interface to the system, such as "os", "time" and "net".  Use those
-// packages rather than this one if you can.
+// primitives.  The details vary depending on the underlying system, and
+// by default, godoc will display the syscall documentation for the current
+// system.  If you want godoc to display syscall documentation for another
+// system, set $GOOS and $GOARCH to the desired system.  For example, if
+// you want to view documentation for freebsd/arm on linux/amd64, set $GOOS
+// to freebsd and $GOARCH to arm.
+// The primary use of syscall is inside other packages that provide a more
+// portable interface to the system, such as "os", "time" and "net".  Use
+// those packages rather than this one if you can.
 // For details of the functions and data types in this package consult
 // the manuals for the appropriate operating system.
 // These calls return err == nil to indicate success; otherwise