sd-id128: add new sd_id128_get_machine_app_specific() API

[elogind.git] / src / libelogind / sd-id128 / sd-id128.c

diff --git a/src/libelogind/sd-id128/sd-id128.c b/src/libelogind/sd-id128/sd-id128.c
index e51efb4dd30df558f48489554add70adcd88cd54..43cc86f43f5a25664892eb55e53d71ed43661448 100644 (file)
--- a/src/libelogind/sd-id128/sd-id128.c
+++ b/src/libelogind/sd-id128/sd-id128.c
@@ -129,7 +129,6 @@ _public_ int sd_id128_get_boot(sd_id128_t *ret) {
         return 0;
 }
 
-#if 0 /// UNNEEDED by elogind
 _public_ int sd_id128_get_invocation(sd_id128_t *ret) {
         static thread_local sd_id128_t saved_invocation_id = {};
         int r;
@@ -151,7 +150,6 @@ _public_ int sd_id128_get_invocation(sd_id128_t *ret) {
         *ret = saved_invocation_id;
         return 0;
 }
-#endif // 0
 
 static sd_id128_t make_v4_uuid(sd_id128_t id) {
         /* Stolen from generate_random_uuid() of drivers/char/random.c
@@ -183,3 +181,34 @@ _public_ int sd_id128_randomize(sd_id128_t *ret) {
         *ret = make_v4_uuid(t);
         return 0;
 }
+
+_public_ int sd_id128_get_machine_app_specific(sd_id128_t app_id, sd_id128_t *ret) {
+        _cleanup_(khash_unrefp) khash *h = NULL;
+        sd_id128_t m, result;
+        const void *p;
+        int r;
+
+        assert_return(ret, -EINVAL);
+
+        r = sd_id128_get_machine(&m);
+        if (r < 0)
+                return r;
+
+        r = khash_new_with_key(&h, "hmac(sha256)", &m, sizeof(m));
+        if (r < 0)
+                return r;
+
+        r = khash_put(h, &app_id, sizeof(app_id));
+        if (r < 0)
+                return r;
+
+        r = khash_digest_data(h, &p);
+        if (r < 0)
+                return r;
+
+        /* We chop off the trailing 16 bytes */
+        memcpy(&result, p, MIN(khash_get_size(h), sizeof(result)));
+
+        *ret = make_v4_uuid(result);
+        return 0;
+}