kernel: refine syscall_hook_manager

- Don't unmark process when setuid if syscall tracepoint is in use
- Remark process when app profile updated
- Ensure zygote is marked on first boot

kernel/selinux/selinux.c

@@ -111,7 +111,7 @@ bool is_ksu_domain()
     return is_task_ksu_domain(current_cred());
 }
 
-bool is_zygote(const struct cred* cred)
+bool is_context(const struct cred* cred, const char* context)
 {
     if (!cred) {
         return false;
@@ -126,11 +126,20 @@ bool is_zygote(const struct cred* cred)
     if (err) {
         return false;
     }
-    result = strncmp("u:r:zygote:s0", ctx.context, ctx.len) == 0;
+    result = strncmp(context, ctx.context, ctx.len) == 0;
     __security_release_secctx(&ctx);
     return result;
 }
 
+bool is_zygote(const struct cred* cred)
+{
+    return is_context(cred, "u:r:zygote:s0");
+}
+
+bool is_init(const struct cred* cred) {
+    return is_context(cred, "u:r:init:s0");
+}
+
 #define KSU_FILE_DOMAIN "u:object_r:ksu_file:s0"
 
 u32 ksu_get_ksu_file_sid()