From c2e4f12a12573e1bffe149734888e9750a2d9102 Mon Sep 17 00:00:00 2001
From: "Pascal S. de Kloe" <pascal@quies.net>
Date: Fri, 6 Oct 2017 03:48:43 +0200
Subject: [PATCH 1/4] List RX ports on Linux. (issue #36)

---
 list_linux.go      | 23 +++++++++++++++++++++++
 list_linux_test.go | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 list_linux.go
 create mode 100644 list_linux_test.go

diff --git a/list_linux.go b/list_linux.go
new file mode 100644
index 0000000..d781f60
--- /dev/null
+++ b/list_linux.go
@@ -0,0 +1,23 @@
+package serial
+
+import (
+	"path/filepath"
+	"sort"
+)
+
+// ListRX returns the detected serial ports sorted.
+func ListRX() (names []string, err error) {
+	matches, err := filepath.Glob("/sys/class/tty/*/rx_trig_bytes")
+	if err != nil {
+		return nil, err
+	}
+
+	names = make([]string, len(matches))
+	for i, m := range matches {
+		names[i] = "/dev/" + filepath.Base(filepath.Dir(m))
+	}
+
+	sort.Strings(names)
+
+	return
+}
diff --git a/list_linux_test.go b/list_linux_test.go
new file mode 100644
index 0000000..a3e51e3
--- /dev/null
+++ b/list_linux_test.go
@@ -0,0 +1,38 @@
+package serial
+
+import (
+	"os"
+	"testing"
+)
+
+func TestListRX(t *testing.T) {
+	port0 := os.Getenv("PORT0")
+	port1 := os.Getenv("PORT1")
+
+	names, err := List()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, name := range names {
+		t.Log("got", name)
+
+		switch {
+		case name == port0:
+			port0 = ""
+		case name == port1:
+			port1 = ""
+		}
+
+		if _, err := os.Lstat(name); err != nil {
+			t.Errorf("%s: unreachable: %s", name, err)
+		}
+	}
+
+	if port0 != "" {
+		t.Errorf("PORT0=%q not found", port0)
+	}
+	if port1 != "" {
+		t.Errorf("PORT1=%q not found", port1)
+	}
+}

From e2deb6ac7ea2a024feb7734d02bedcbb49ce42ee Mon Sep 17 00:00:00 2001
From: "Pascal S. de Kloe" <pascal@quies.net>
Date: Fri, 6 Oct 2017 03:54:20 +0200
Subject: [PATCH 2/4] Function name typo.

---
 list_linux_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/list_linux_test.go b/list_linux_test.go
index a3e51e3..2ef39e1 100644
--- a/list_linux_test.go
+++ b/list_linux_test.go
@@ -9,7 +9,7 @@ func TestListRX(t *testing.T) {
 	port0 := os.Getenv("PORT0")
 	port1 := os.Getenv("PORT1")
 
-	names, err := List()
+	names, err := ListRX()
 	if err != nil {
 		t.Fatal(err)
 	}

From 47dd4af4b7373625406f7f1605c0c583c089d5c0 Mon Sep 17 00:00:00 2001
From: "Pascal S. de Kloe" <pascal@quies.net>
Date: Fri, 6 Oct 2017 04:25:31 +0200
Subject: [PATCH 3/4] Resolve device file from uevent (to skip missing device
 files).

---
 list_linux.go | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/list_linux.go b/list_linux.go
index d781f60..546d3af 100644
--- a/list_linux.go
+++ b/list_linux.go
@@ -1,6 +1,9 @@
 package serial
 
 import (
+	"bytes"
+	"io/ioutil"
+	"os"
 	"path/filepath"
 	"sort"
 )
@@ -12,9 +15,18 @@ func ListRX() (names []string, err error) {
 		return nil, err
 	}
 
-	names = make([]string, len(matches))
-	for i, m := range matches {
-		names[i] = "/dev/" + filepath.Base(filepath.Dir(m))
+	names = make([]string, 0, len(matches))
+	for _, m := range matches {
+		uevent, err := ioutil.ReadFile(filepath.Clean(m + "/../uevent"))
+		if err != nil && !os.IsNotExist(err) {
+			return nil, err
+		}
+		for _, line := range bytes.Split(uevent, []byte{'\n'}) {
+			if bytes.HasPrefix(line, []byte("DEVNAME=")) {
+				names = append(names, "/dev/"+string(line[8:]))
+				break
+			}
+		}
 	}
 
 	sort.Strings(names)

From 9afef3034f5cfae43c0c81fdf6015216e383f81c Mon Sep 17 00:00:00 2001
From: "Pascal S. de Kloe" <pascal@quies.net>
Date: Fri, 6 Oct 2017 04:34:10 +0200
Subject: [PATCH 4/4] Check for device file existence too.

---
 list_linux.go      | 10 +++++++++-
 list_linux_test.go |  4 ----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/list_linux.go b/list_linux.go
index 546d3af..13b6fe3 100644
--- a/list_linux.go
+++ b/list_linux.go
@@ -21,12 +21,20 @@ func ListRX() (names []string, err error) {
 		if err != nil && !os.IsNotExist(err) {
 			return nil, err
 		}
+
+		var name string
 		for _, line := range bytes.Split(uevent, []byte{'\n'}) {
 			if bytes.HasPrefix(line, []byte("DEVNAME=")) {
-				names = append(names, "/dev/"+string(line[8:]))
+				name = "/dev/" + string(line[8:])
 				break
 			}
 		}
+
+		if _, err := os.Lstat(name); err == nil {
+			names = append(names, name)
+		} else if !os.IsNotExist(err) {
+			return nil, err
+		}
 	}
 
 	sort.Strings(names)
diff --git a/list_linux_test.go b/list_linux_test.go
index 2ef39e1..b153af6 100644
--- a/list_linux_test.go
+++ b/list_linux_test.go
@@ -23,10 +23,6 @@ func TestListRX(t *testing.T) {
 		case name == port1:
 			port1 = ""
 		}
-
-		if _, err := os.Lstat(name); err != nil {
-			t.Errorf("%s: unreachable: %s", name, err)
-		}
 	}
 
 	if port0 != "" {