From 2d5c53fc34411fa118b2b8824fab2497ec5984c8 Mon Sep 17 00:00:00 2001
From: Mike Yuan <me@yhndnzj.com>
Date: Mon, 10 Jul 2023 20:58:57 +0800
Subject: [PATCH] shared/device-nodes: add devnode_same

---
 src/shared/device-nodes.c | 27 +++++++++++++++++++++++++++
 src/shared/device-nodes.h |  2 ++
 2 files changed, 29 insertions(+)

diff --git a/src/shared/device-nodes.c b/src/shared/device-nodes.c
index bdbbb98c2c..d08c40fe2c 100644
--- a/src/shared/device-nodes.c
+++ b/src/shared/device-nodes.c
@@ -3,8 +3,10 @@
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
+#include <sys/stat.h>
 
 #include "device-nodes.h"
+#include "path-util.h"
 #include "string-util.h"
 #include "utf8.h"
 
@@ -58,3 +60,28 @@ int encode_devnode_name(const char *str, char *str_enc, size_t len) {
         str_enc[j] = '\0';
         return 0;
 }
+
+int devnode_same(const char *a, const char *b) {
+        struct stat sa, sb;
+
+        assert(a);
+        assert(b);
+
+        if (!valid_device_node_path(a) || !valid_device_node_path(b))
+                return -EINVAL;
+
+        if (stat(a, &sa) < 0)
+                return -errno;
+        if (stat(b, &sb) < 0)
+                return -errno;
+
+        if (!S_ISBLK(sa.st_mode) && !S_ISCHR(sa.st_mode))
+                return -ENODEV;
+        if (!S_ISBLK(sb.st_mode) && !S_ISCHR(sb.st_mode))
+                return -ENODEV;
+
+        if (((sa.st_mode ^ sb.st_mode) & S_IFMT) != 0) /* both inode same device node type? */
+                return false;
+
+        return sa.st_rdev == sb.st_rdev;
+}
diff --git a/src/shared/device-nodes.h b/src/shared/device-nodes.h
index a8b2564314..8b17a8e190 100644
--- a/src/shared/device-nodes.h
+++ b/src/shared/device-nodes.h
@@ -5,3 +5,5 @@
 
 int encode_devnode_name(const char *str, char *str_enc, size_t len);
 int allow_listed_char_for_devnode(char c, const char *additional);
+
+int devnode_same(const char *a, const char *b);