From 0d7303b798e85da6a2c9cd6d86f0d9f165ceb4c4 Mon Sep 17 00:00:00 2001
From: Derek Kaser <derek.kaser@gmail.com>
Date: Tue, 2 May 2023 23:57:52 -0400
Subject: [PATCH] various: add detection and Taildrop for Unraid

Updates tailscale/tailscale#8025

Signed-off-by: Derek Kaser <derek.kaser@gmail.com>
---
 cmd/tailscale/cli/diag.go  |  2 +-
 cmd/tailscaled/taildrop.go | 26 +++++++++++++++++++++++++-
 hostinfo/hostinfo_linux.go |  4 ++++
 ipn/ipnlocal/peerapi.go    |  5 +++++
 version/distro/distro.go   |  3 +++
 5 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/cmd/tailscale/cli/diag.go b/cmd/tailscale/cli/diag.go
index 5ed6ba92b..ebf26985f 100644
--- a/cmd/tailscale/cli/diag.go
+++ b/cmd/tailscale/cli/diag.go
@@ -66,7 +66,7 @@ func isSystemdSystem() bool {
 		return false
 	}
 	switch distro.Get() {
-	case distro.QNAP, distro.Gokrazy, distro.Synology:
+	case distro.QNAP, distro.Gokrazy, distro.Synology, distro.Unraid:
 		return false
 	}
 	_, err := exec.LookPath("systemctl")
diff --git a/cmd/tailscaled/taildrop.go b/cmd/tailscaled/taildrop.go
index 71be089db..11f026e27 100644
--- a/cmd/tailscaled/taildrop.go
+++ b/cmd/tailscaled/taildrop.go
@@ -18,7 +18,7 @@
 func configureTaildrop(logf logger.Logf, lb *ipnlocal.LocalBackend) {
 	dg := distro.Get()
 	switch dg {
-	case distro.Synology, distro.TrueNAS, distro.QNAP:
+	case distro.Synology, distro.TrueNAS, distro.QNAP, distro.Unraid:
 		// See if they have a "Taildrop" share.
 		// See https://github.com/tailscale/tailscale/issues/2179#issuecomment-982821319
 		path, err := findTaildropDir(dg)
@@ -42,6 +42,8 @@ func findTaildropDir(dg distro.Distro) (string, error) {
 		return findTrueNASTaildropDir(name)
 	case distro.QNAP:
 		return findQnapTaildropDir(name)
+	case distro.Unraid:
+		return findUnraidTaildropDir(name)
 	}
 	return "", fmt.Errorf("%s is an unsupported distro for Taildrop dir", dg)
 }
@@ -103,3 +105,25 @@ func findQnapTaildropDir(name string) (string, error) {
 	}
 	return "", fmt.Errorf("shared folder %q not found", name)
 }
+
+// findUnraidTaildropDir looks for a directory linked at
+// /var/lib/tailscale/Taildrop. This is a symlink to the
+// path specified by the user in the Unraid Web UI
+func findUnraidTaildropDir(name string) (string, error) {
+	dir := fmt.Sprintf("/var/lib/tailscale/%s", name)
+	_, err := os.Stat(dir)
+	if err != nil {
+		return "", fmt.Errorf("symlink %q not found", name)
+	}
+
+	fullpath, err := filepath.EvalSymlinks(dir)
+	if err != nil {
+		return "", fmt.Errorf("symlink %q to shared folder not valid", name)
+	}
+
+	fi, err := os.Stat(fullpath)
+	if err == nil && fi.IsDir() {
+		return dir, nil // return the symlink
+	}
+	return "", fmt.Errorf("shared folder %q not found", name)
+}
diff --git a/hostinfo/hostinfo_linux.go b/hostinfo/hostinfo_linux.go
index 6c2ab8ff8..d52c084b8 100644
--- a/hostinfo/hostinfo_linux.go
+++ b/hostinfo/hostinfo_linux.go
@@ -95,6 +95,8 @@ func linuxVersionMeta() (meta versionMeta) {
 		propFile = "/etc.defaults/VERSION"
 	case distro.OpenWrt:
 		propFile = "/etc/openwrt_release"
+	case distro.Unraid:
+		propFile = "/etc/unraid-version"
 	case distro.WDMyCloud:
 		slurp, _ := os.ReadFile("/etc/version")
 		meta.DistroVersion = string(bytes.TrimSpace(slurp))
@@ -153,6 +155,8 @@ func linuxVersionMeta() (meta versionMeta) {
 		meta.DistroVersion = m["productversion"]
 	case distro.OpenWrt:
 		meta.DistroVersion = m["DISTRIB_RELEASE"]
+	case distro.Unraid:
+		meta.DistroVersion = m["version"]
 	}
 	return
 }
diff --git a/ipn/ipnlocal/peerapi.go b/ipn/ipnlocal/peerapi.go
index fa749d995..e8e06b6ee 100644
--- a/ipn/ipnlocal/peerapi.go
+++ b/ipn/ipnlocal/peerapi.go
@@ -49,6 +49,7 @@
 	"tailscale.com/tailcfg"
 	"tailscale.com/util/clientmetric"
 	"tailscale.com/util/multierr"
+	"tailscale.com/version/distro"
 	"tailscale.com/wgengine"
 	"tailscale.com/wgengine/filter"
 )
@@ -1090,6 +1091,10 @@ func (h *peerAPIHandler) handlePeerPut(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, errNoTaildrop.Error(), http.StatusInternalServerError)
 		return
 	}
+	if distro.Get() == distro.Unraid && !h.ps.directFileMode {
+		http.Error(w, "Taildrop folder not configured or accessible", http.StatusInternalServerError)
+		return
+	}
 	rawPath := r.URL.EscapedPath()
 	suffix, ok := strings.CutPrefix(rawPath, "/v0/put/")
 	if !ok {
diff --git a/version/distro/distro.go b/version/distro/distro.go
index 0724265a4..e319d1ba7 100644
--- a/version/distro/distro.go
+++ b/version/distro/distro.go
@@ -29,6 +29,7 @@
 	TrueNAS   = Distro("truenas")
 	Gokrazy   = Distro("gokrazy")
 	WDMyCloud = Distro("wdmycloud")
+	Unraid    = Distro("unraid")
 )
 
 var distro lazy.SyncValue[Distro]
@@ -90,6 +91,8 @@ func linuxDistro() Distro {
 		return WDMyCloud
 	case have("/usr/sbin/wd_crontab.sh"): // Western Digital MyCloud OS5
 		return WDMyCloud
+	case have("/etc/unraid-version"):
+		return Unraid
 	}
 	return ""
 }