1 files changed, 83 insertions, 0 deletions
diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
new file mode 100644
index 000000000000..43b551468c2a
--- /dev/null
+++ b/tools/include/nolibc/crt.h
@@ -0,0 +1,83 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * C Run Time support for NOLIBC
+ * Copyright (C) 2023 Zhangjin Wu <falcon@tinylab.org>
+ */
+
+#ifndef _NOLIBC_CRT_H
+#define _NOLIBC_CRT_H
+
+char **environ __attribute__((weak));
+const unsigned long *_auxv __attribute__((weak));
+
+static void __stack_chk_init(void);
+static void exit(int);
+
+extern void (*const __preinit_array_start[])(void) __attribute__((weak));
+extern void (*const __preinit_array_end[])(void) __attribute__((weak));
+
+extern void (*const __init_array_start[])(void) __attribute__((weak));
+extern void (*const __init_array_end[])(void) __attribute__((weak));
+
+extern void (*const __fini_array_start[])(void) __attribute__((weak));
+extern void (*const __fini_array_end[])(void) __attribute__((weak));
+
+__attribute__((weak))
+void _start_c(long *sp)
+{
+	long argc;
+	char **argv;
+	char **envp;
+	int exitcode;
+	void (* const *func)(void);
+	const unsigned long *auxv;
+	/* silence potential warning: conflicting types for 'main' */
+	int _nolibc_main(int, char **, char **) __asm__ ("main");
+
+	/* initialize stack protector */
+	__stack_chk_init();
+
+	/*
+	 * sp  :    argc          <-- argument count, required by main()
+	 * argv:    argv[0]       <-- argument vector, required by main()
+	 *          argv[1]
+	 *          ...
+	 *          argv[argc-1]
+	 *          null
+	 * environ: environ[0]    <-- environment variables, required by main() and getenv()
+	 *          environ[1]
+	 *          ...
+	 *          null
+	 * _auxv:   _auxv[0]      <-- auxiliary vector, required by getauxval()
+	 *          _auxv[1]
+	 *          ...
+	 *          null
+	 */
+
+	/* assign argc and argv */
+	argc = *sp;
+	argv = (void *)(sp + 1);
+
+	/* find environ */
+	environ = envp = argv + argc + 1;
+
+	/* find _auxv */
+	for (auxv = (void *)envp; *auxv++;)
+		;
+	_auxv = auxv;
+
+	for (func = __preinit_array_start; func < __preinit_array_end; func++)
+		(*func)();
+	for (func = __init_array_start; func < __init_array_end; func++)
+		(*func)();
+
+	/* go to application */
+	exitcode = _nolibc_main(argc, argv, envp);
+
+	for (func = __fini_array_end; func > __fini_array_start;)
+		(*--func)();
+
+	exit(exitcode);
+}
+
+#endif /* _NOLIBC_CRT_H */