1 files changed, 108 insertions, 0 deletions
diff --git a/src/syscall/env_plan9.go b/src/syscall/env_plan9.go
new file mode 100644
index 000000000..9ea36c886
--- /dev/null
+++ b/src/syscall/env_plan9.go
@@ -0,0 +1,108 @@
+// 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.
+
+// Plan 9 environment variables.
+
+package syscall
+
+import (
+	"errors"
+)
+
+var (
+	errZeroLengthKey = errors.New("zero length key")
+	errShortWrite    = errors.New("i/o count too small")
+)
+
+func readenv(key string) (string, error) {
+	fd, err := Open("/env/"+key, O_RDONLY)
+	if err != nil {
+		return "", err
+	}
+	defer Close(fd)
+	l, _ := Seek(fd, 0, 2)
+	Seek(fd, 0, 0)
+	buf := make([]byte, l)
+	n, err := Read(fd, buf)
+	if err != nil {
+		return "", err
+	}
+	if n > 0 && buf[n-1] == 0 {
+		buf = buf[:n-1]
+	}
+	return string(buf), nil
+}
+
+func writeenv(key, value string) error {
+	fd, err := Create("/env/"+key, O_RDWR, 0666)
+	if err != nil {
+		return err
+	}
+	defer Close(fd)
+	b := []byte(value)
+	n, err := Write(fd, b)
+	if err != nil {
+		return err
+	}
+	if n != len(b) {
+		return errShortWrite
+	}
+	return nil
+}
+
+func Getenv(key string) (value string, found bool) {
+	if len(key) == 0 {
+		return "", false
+	}
+	v, err := readenv(key)
+	if err != nil {
+		return "", false
+	}
+	return v, true
+}
+
+func Setenv(key, value string) error {
+	if len(key) == 0 {
+		return errZeroLengthKey
+	}
+	err := writeenv(key, value)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func Clearenv() {
+	RawSyscall(SYS_RFORK, RFCENVG, 0, 0)
+}
+
+func Unsetenv(key string) error {
+	if len(key) == 0 {
+		return errZeroLengthKey
+	}
+	Remove("/env/" + key)
+	return nil
+}
+
+func Environ() []string {
+	fd, err := Open("/env", O_RDONLY)
+	if err != nil {
+		return nil
+	}
+	defer Close(fd)
+	files, err := readdirnames(fd)
+	if err != nil {
+		return nil
+	}
+	ret := make([]string, 0, len(files))
+
+	for _, key := range files {
+		v, err := readenv(key)
+		if err != nil {
+			continue
+		}
+		ret = append(ret, key+"="+v)
+	}
+	return ret
+}