From ebfeec9fb45e89f6134243bf7ce7625ae2b52a89 Mon Sep 17 00:00:00 2001
From: ishuah <kariuki@ishuah.com>
Date: Fri, 2 Mar 2018 16:30:04 +0300
Subject: [PATCH] mount: run rclone mount in the background - fixes #723

---
 cmd/mountlib/daemon.go                | 15 +++++++++++++
 cmd/mountlib/daemon_unix.go           | 32 +++++++++++++++++++++++++++
 cmd/mountlib/mount.go                 | 11 ++++++++-
 docs/content/commands/rclone_mount.md | 14 +++++++++---
 4 files changed, 68 insertions(+), 4 deletions(-)
 create mode 100644 cmd/mountlib/daemon.go
 create mode 100644 cmd/mountlib/daemon_unix.go

diff --git a/cmd/mountlib/daemon.go b/cmd/mountlib/daemon.go
new file mode 100644
index 000000000..a8124fef9
--- /dev/null
+++ b/cmd/mountlib/daemon.go
@@ -0,0 +1,15 @@
+// Daemonization interface for non-Unix variants only
+
+// +build windows darwin,!cgo
+
+package mountlib
+
+import (
+	"log"
+	"runtime"
+)
+
+func startBackgroundMode() bool {
+	log.Fatalf("background mode not supported on %s platform", runtime.GOOS)
+	return false
+}
diff --git a/cmd/mountlib/daemon_unix.go b/cmd/mountlib/daemon_unix.go
new file mode 100644
index 000000000..318f5a3d0
--- /dev/null
+++ b/cmd/mountlib/daemon_unix.go
@@ -0,0 +1,32 @@
+// Daemonization interface for Unix variants only
+
+// +build !windows
+// +build !darwin cgo
+
+package mountlib
+
+import (
+	"log"
+
+	"github.com/sevlyar/go-daemon"
+)
+
+func startBackgroundMode() bool {
+	cntxt := &daemon.Context{}
+	d, err := cntxt.Reborn()
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	if d != nil {
+		return true
+	}
+
+	defer func() {
+		if err := cntxt.Release(); err != nil {
+			log.Printf("error encountered while killing daemon: %v", err)
+		}
+	}()
+
+	return false
+}
diff --git a/cmd/mountlib/mount.go b/cmd/mountlib/mount.go
index b5863097d..980106ce7 100644
--- a/cmd/mountlib/mount.go
+++ b/cmd/mountlib/mount.go
@@ -23,6 +23,7 @@ var (
 	AllowOther                       = false
 	DefaultPermissions               = false
 	WritebackCache                   = false
+	Daemon                           = false
 	MaxReadAhead       fs.SizeSuffix = 128 * 1024
 	ExtraOptions       []string
 	ExtraFlags         []string
@@ -174,6 +175,14 @@ will see all files and folders immediately in this mode.
 				}
 			}
 
+			// Start background task if --background is specified
+			if Daemon {
+				daemonized := startBackgroundMode()
+				if daemonized {
+					return
+				}
+			}
+
 			err := Mount(fdst, args[1])
 			if err != nil {
 				log.Fatalf("Fatal error: %v", err)
@@ -196,7 +205,7 @@ will see all files and folders immediately in this mode.
 	flags.FVarP(flagSet, &MaxReadAhead, "max-read-ahead", "", "The number of bytes that can be prefetched for sequential reads.")
 	flags.StringArrayVarP(flagSet, &ExtraOptions, "option", "o", []string{}, "Option for libfuse/WinFsp. Repeat if required.")
 	flags.StringArrayVarP(flagSet, &ExtraFlags, "fuse-flag", "", []string{}, "Flags or arguments to be passed direct to libfuse/WinFsp. Repeat if required.")
-	//flags.BoolVarP(flagSet, &foreground, "foreground", "", foreground, "Do not detach.")
+	flags.BoolVarP(flagSet, &Daemon, "daemon", "", Daemon, "Run mount as a daemon (background mode).")
 
 	// Add in the generic flags
 	vfsflags.AddFlags(flagSet)
diff --git a/docs/content/commands/rclone_mount.md b/docs/content/commands/rclone_mount.md
index a5c221553..8fa9ea3b2 100644
--- a/docs/content/commands/rclone_mount.md
+++ b/docs/content/commands/rclone_mount.md
@@ -20,6 +20,11 @@ This is **EXPERIMENTAL** - use with care.
 
 First set up your remote using `rclone config`.  Check it works with `rclone ls` etc.
 
+You can either run mount in foreground mode or background(daemon) mode. Mount runs in
+foreground mode by default, use the `--daemon` flag to specify background mode mode.
+Background mode is only supported on Linux and OSX, you can only run mount in
+foreground mode on Windows.
+
 Start the mount like this
 
     rclone mount remote:path/to/files /path/to/local/mount
@@ -28,12 +33,15 @@ Or on Windows like this where X: is an unused drive letter
 
     rclone mount remote:path/to/files X:
 
-When the program ends, either via Ctrl+C or receiving a SIGINT or SIGTERM signal,
-the mount is automatically stopped.
+When running in background mode the user will have to stop the mount manually (specified below).
+
+When the program ends while in foreground mode, either via Ctrl+C or receiving
+a SIGINT or SIGTERM signal, the mount is automatically stopped.
 
 The umount operation can fail, for example when the mountpoint is busy.
-When that happens, it is the user's responsibility to stop the mount manually with
+When that happens, it is the user's responsibility to stop the mount manually.
 
+Stopping the mount manually:
     # Linux
     fusermount -u /path/to/local/mount
     # OS X