1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
 2/*
 3 * C Run Time support for NOLIBC
 4 * Copyright (C) 2023 Zhangjin Wu <falcon@tinylab.org>
 5 */
 6
 7#ifndef _NOLIBC_CRT_H
 8#define _NOLIBC_CRT_H
 9
10char **environ __attribute__((weak));
11const unsigned long *_auxv __attribute__((weak));
12
13static void __stack_chk_init(void);
14static void exit(int);
15
16extern void (*const __preinit_array_start[])(int, char **, char**) __attribute__((weak));
17extern void (*const __preinit_array_end[])(int, char **, char**) __attribute__((weak));
18
19extern void (*const __init_array_start[])(int, char **, char**) __attribute__((weak));
20extern void (*const __init_array_end[])(int, char **, char**) __attribute__((weak));
21
22extern void (*const __fini_array_start[])(void) __attribute__((weak));
23extern void (*const __fini_array_end[])(void) __attribute__((weak));
24
25__attribute__((weak,used))
26void _start_c(long *sp)
27{
28	long argc;
29	char **argv;
30	char **envp;
31	int exitcode;
32	void (* const *ctor_func)(int, char **, char **);
33	void (* const *dtor_func)(void);
34	const unsigned long *auxv;
35	/* silence potential warning: conflicting types for 'main' */
36	int _nolibc_main(int, char **, char **) __asm__ ("main");
37
38	/* initialize stack protector */
39	__stack_chk_init();
40
41	/*
42	 * sp  :    argc          <-- argument count, required by main()
43	 * argv:    argv[0]       <-- argument vector, required by main()
44	 *          argv[1]
45	 *          ...
46	 *          argv[argc-1]
47	 *          null
48	 * environ: environ[0]    <-- environment variables, required by main() and getenv()
49	 *          environ[1]
50	 *          ...
51	 *          null
52	 * _auxv:   _auxv[0]      <-- auxiliary vector, required by getauxval()
53	 *          _auxv[1]
54	 *          ...
55	 *          null
56	 */
57
58	/* assign argc and argv */
59	argc = *sp;
60	argv = (void *)(sp + 1);
61
62	/* find environ */
63	environ = envp = argv + argc + 1;
64
65	/* find _auxv */
66	for (auxv = (void *)envp; *auxv++;)
67		;
68	_auxv = auxv;
69
70	for (ctor_func = __preinit_array_start; ctor_func < __preinit_array_end; ctor_func++)
71		(*ctor_func)(argc, argv, envp);
72	for (ctor_func = __init_array_start; ctor_func < __init_array_end; ctor_func++)
73		(*ctor_func)(argc, argv, envp);
74
75	/* go to application */
76	exitcode = _nolibc_main(argc, argv, envp);
77
78	for (dtor_func = __fini_array_end; dtor_func > __fini_array_start;)
79		(*--dtor_func)();
80
81	exit(exitcode);
82}
83
84#endif /* _NOLIBC_CRT_H */