initial commit

1 files changed, 101 insertions, 0 deletions

diff --git a/src/util/fd.go b/src/util/fd.go
new file mode 100644
index 0000000..17c64cd
--- /dev/null
+++ b/src/util/fd.go
@@ -0,0 +1,101 @@
+// Copyright 2015-2016 Luke Shumaker
+
+package util
+
+import (
+	"net"
+	"os"
+	"strings"
+	"fmt"
+	"sync"
+	"strconv"
+
+	sd "lukeshu.com/git/go/libsystemd/sd_daemon"
+)
+
+var fdsLock sync.Mutex
+var fds = map[int]*os.File{}
+var sdFds = map[string]int{}
+
+func init() {
+	fds[0] = os.Stdin
+	fds[1] = os.Stdout
+	fds[2] = os.Stderr
+	fromSd := sd.ListenFds(true)
+	if fromSd == nil {
+		return
+	}
+	for i, file := range fromSd {
+		fds[i+3] = file
+		sdFds[file.Name()] = i+3
+	}
+}
+
+func FdNameToNum(name string) int {
+	switch name {
+	case "stdin":
+		return 0
+	case "stdout":
+		return 1
+	case "stderr":
+		return 2
+	case "systemd":
+		if len(sdFds) == 0 {
+			return -1
+		}
+		return 3
+	default:
+		if n, err := strconv.Atoi(name); err == nil {
+			if n >= 0 {
+				return n
+			}
+		} else if strings.HasPrefix(name, "systemd:") {
+			name = strings.TrimPrefix(name, "systemd")
+			n, ok := sdFds[name]
+			if ok {
+				return n
+			} else if n, err := strconv.Atoi(name); err == nil && n < len(sdFds) {
+				return n+3
+			}
+		}
+		return -1
+	}
+}
+
+func FdFile(fd int) *os.File {
+	fdsLock.Lock()
+	defer fdsLock.Unlock()
+	file, ok := fds[fd]
+	if ok {
+		return file
+	}
+	file = os.NewFile(uintptr(fd), fmt.Sprintf("/dev/fd/%d", fd))
+	fds[fd] = file
+	return file
+}
+
+func StreamListener(stype, saddr string) (net.Listener, error) {
+	switch stype {
+	case "fd":
+		return net.FileListener(FdFile(FdNameToNum(saddr)))
+	default: /* case "tcp", "tcp4", "tcp6", "unix", "unixpacket": */
+		return net.Listen(stype, saddr)
+	}
+}
+
+func PacketListener(stype, saddr string) (net.PacketConn, error) {
+	switch stype {
+	case "fd":
+		return net.FilePacketConn(FdFile(FdNameToNum(saddr)))
+	default: /* case "udp", "udp4", "udp6", "ip", "ip4", "ip6", "unixgram": */
+		return net.ListenPacket(stype, saddr)
+	}
+}
+
+// For completeless, I might want to implement methods for each of
+// these:
+//  - FIFO
+//  - Special
+//  - Netlink
+//  - MessageQueue
+//  - USBFunction