From 9ef572bc95ada897e6bf58e328adb7cdeb6bd2f4 Mon Sep 17 00:00:00 2001
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date: Wed, 27 Nov 2019 15:36:46 +0900
Subject: [PATCH] hwdep: add global method to get devnode string for hwdep
 device

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 src/hwdep/alsahwdep.map |  1 +
 src/hwdep/query.c       | 55 +++++++++++++++++++++++++++++++++++++++++
 src/hwdep/query.h       |  3 +++
 3 files changed, 59 insertions(+)

diff --git a/src/hwdep/alsahwdep.map b/src/hwdep/alsahwdep.map
index 466d65a..5b5eb5b 100644
--- a/src/hwdep/alsahwdep.map
+++ b/src/hwdep/alsahwdep.map
@@ -4,6 +4,7 @@ ALSA_GOBJECT_0_0_0 {
 
     "alsahwdep_get_device_id_list";
     "alsahwdep_get_hwdep_sysname";
+    "alsahwdep_get_hwdep_devnode";
   local:
     *;
 };
diff --git a/src/hwdep/query.c b/src/hwdep/query.c
index 1b0a836..eaf9c13 100644
--- a/src/hwdep/query.c
+++ b/src/hwdep/query.c
@@ -245,3 +245,58 @@ void alsahwdep_get_hwdep_sysname(guint card_id, guint device_id,
 
     udev_unref(ctx);
 }
+
+/**
+ * alsahwdep_get_hwdep_devnode:
+ * @card_id: The numeridcal ID of sound card.
+ * @device_id: The numerical ID of hwdep device for the sound card.
+ * @devnode: (out): The string for devnode of hwdep device.
+ * @error: A #GError.
+ *
+ * Allocate devnode string for hwdep device and return it when exists.
+ */
+void alsahwdep_get_hwdep_devnode(guint card_id, guint device_id,
+                                 char **devnode, GError **error)
+{
+    unsigned int length;
+    char *name;
+    struct udev *ctx;
+    struct udev_device *dev;
+    const char *node;
+
+    length = strlen(HWDEP_SYSNAME_TEMPLATE) + calculate_digits(card_id) +
+             calculate_digits(device_id) + 1;
+    name = g_try_malloc0(length);
+    if (name == NULL) {
+        generate_error(error, ENOMEM);
+        return;
+    }
+    snprintf(name, length, HWDEP_SYSNAME_TEMPLATE, card_id, device_id);
+
+    ctx = udev_new();
+    if (ctx == NULL) {
+        generate_error(error, errno);
+        g_free(name);
+        return;
+    }
+
+    dev = udev_device_new_from_subsystem_sysname(ctx, "sound", name);
+    g_free(name);
+    if (dev == NULL) {
+        generate_error(error, ENODEV);
+        udev_unref(ctx);
+        return;
+    }
+
+    node = udev_device_get_devnode(dev);
+    if (node == NULL) {
+        generate_error(error, ENOENT);
+    } else {
+        *devnode = strdup(node);
+        if (*devnode == NULL)
+            generate_error(error, ENOMEM);
+    }
+
+    udev_device_unref(dev);
+    udev_unref(ctx);
+}
diff --git a/src/hwdep/query.h b/src/hwdep/query.h
index 4eed987..ed005ef 100644
--- a/src/hwdep/query.h
+++ b/src/hwdep/query.h
@@ -13,6 +13,9 @@ void alsahwdep_get_device_id_list(guint card_id, guint **entries,
 void alsahwdep_get_hwdep_sysname(guint card_id, guint device_id,
                                  char **sysname, GError **error);
 
+void alsahwdep_get_hwdep_devnode(guint card_id, guint device_id,
+                                 char **devnode, GError **error);
+
 G_END_DECLS
 
 #endif
-- 
2.47.3