[openwrt/openwrt] base-files: introduce a function to get kernel version number

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/a0fe3cfb62fbf0b5f599c90e488727f493223429

commit a0fe3cfb62fbf0b5f599c90e488727f493223429
Author: Shiji Yang <yangshiji66 at outlook.com>
AuthorDate: Tue Jun 17 22:06:38 2025 +0800

    base-files: introduce a function to get kernel version number
    
    A new function "get_linux_version()" to normalize and print the
    kernel version as an integer. In some migration scripts, it is
    useful for checking the Linux kernel version.
    
    Signed-off-by: Shiji Yang <yangshiji66 at outlook.com>
    Link: https://github.com/openwrt/openwrt/pull/19172
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 package/base-files/files/lib/functions/system.sh | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/package/base-files/files/lib/functions/system.sh b/package/base-files/files/lib/functions/system.sh
index f43281b5dc..eaed0fba11 100644
--- a/package/base-files/files/lib/functions/system.sh
+++ b/package/base-files/files/lib/functions/system.sh
@@ -315,3 +315,10 @@ macaddr_canonicalize() {
 dt_is_enabled() {
 	grep -q okay "/proc/device-tree/$1/status"
 }
+
+get_linux_version() {
+	local ver=$(uname -r)
+	local minor=${ver%\.*}
+
+	printf "%d%02d%03d" ${ver%%\.*} ${minor#*\.} ${ver##*\.} 2>/dev/null
+}