1 files changed, 45 insertions, 0 deletions
diff --git a/libc/bionic/sysprop_helpers.h b/libc/bionic/sysprop_helpers.h
new file mode 100644
index 000000000..a02c2dc41
--- /dev/null
+++ b/libc/bionic/sysprop_helpers.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <sys/cdefs.h>
+
+// Get the presiding config string, in the following order of priority:
+//   1. Environment variables.
+//   2. System properties, in the order they're specified in sys_prop_names.
+// If neither of these options are specified (or they're both an empty string),
+// this function returns false. Otherwise, it returns true, and the presiding
+// options string is written to the `options` buffer of size `size`. If this
+// function returns true, `options` is guaranteed to be null-terminated.
+// `options_size` should be at least PROP_VALUE_MAX.
+__LIBC_HIDDEN__ bool get_config_from_env_or_sysprops(const char* env_var_name,
+                                                     const char* const* sys_prop_names,
+                                                     size_t sys_prop_names_size, char* options,
+                                                     size_t options_size);