detect musl

content/posts/2022/c/detect-musl.md

@@ -0,0 +1,45 @@
+---
+title: "Detect Musl"
+date: 2022-07-31T16:00:15+03:00
+draft: false
+tags: [linux, c, shell, musl]
+---
+
+Пост — чистейшая копипаста с [SoF](https://stackoverflow.com/questions/58177815/how-to-actually-detect-musl-libc).
+
+```sh
+#! /bin/sh
+
+tmpf=/tmp/musl.log
+
+# Detect Musl C library.
+libc=$(ldd /bin/ls | grep 'musl' | head -1 | cut -d ' ' -f1)
+if [ -z $libc ]; then
+    # This is not Musl.
+    rm -f ${tmpf}
+    exit 1
+fi
+$libc >${tmpf} 2>&1
+vstr=$(cat ${tmpf} | grep "Version" | cut -d ' ' -f2)
+
+v_major=$(echo $vstr | cut -d '.' -f1)
+v_minor=$(echo $vstr | cut -d '.' -f2)
+v_patch=$(echo $vstr | cut -d '.' -f3)
+
+rm -f ${tmpf}
+
+echo "-D__MUSL__ -D__MUSL_VER_MAJOR__=${v_major} -D__MUSL_VER_MINOR__=${v_minor} -D__MUSL_VER_PATCH__=${v_patch}"
+```
+
+```sh
+$ ./detect-musl.sh 
+  -D__MUSL__ -D__MUSL_VER_MAJOR__=1 -D__MUSL_VER_MINOR__=1 -D__MUSL_VER_PATCH__=24
+```
+
+```sh
+$ /lib/ld-musl-x86_64.so.1
+  musl libc (x86_64)
+  Version 1.2.3
+  Dynamic Program Loader
+  Usage: /lib/ld-musl-x86_64.so.1 [options] [--] pathname [args]
+```