1/* Startup support for ELF initializers/finalizers in the main executable.
2 Copyright (C) 2002-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 In addition to the permissions in the GNU Lesser General Public
11 License, the Free Software Foundation gives you unlimited
12 permission to link the compiled version of this file with other
13 programs, and to distribute those programs without any restriction
14 coming from the use of this file. (The GNU Lesser General Public
15 License restrictions do apply in other respects; for example, they
16 cover modification of the file, and distribution when not linked
17 into another program.)
18
19 Note that people who make modified versions of this file are not
20 obligated to grant this special exception for their modified
21 versions; it is their choice whether to do so. The GNU Lesser
22 General Public License gives permission to release a modified
23 version without this exception; this exception also makes it
24 possible to release a modified version which carries forward this
25 exception.
26
27 The GNU C Library is distributed in the hope that it will be useful,
28 but WITHOUT ANY WARRANTY; without even the implied warranty of
29 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
30 Lesser General Public License for more details.
31
32 You should have received a copy of the GNU Lesser General Public
33 License along with the GNU C Library; if not, see
34 <https://www.gnu.org/licenses/>. */
35
36#include <stddef.h>
37#include <elf-initfini.h>
38
39
40/* These magic symbols are provided by the linker. */
41extern void (*__preinit_array_start []) (int, char **, char **)
42 attribute_hidden;
43extern void (*__preinit_array_end []) (int, char **, char **)
44 attribute_hidden;
45extern void (*__init_array_start []) (int, char **, char **)
46 attribute_hidden;
47extern void (*__init_array_end []) (int, char **, char **)
48 attribute_hidden;
49extern void (*__fini_array_start []) (void) attribute_hidden;
50extern void (*__fini_array_end []) (void) attribute_hidden;
51
52
53#if ELF_INITFINI
54/* These function symbols are provided for the .init/.fini section entry
55 points automagically by the linker. */
56extern void _init (void);
57extern void _fini (void);
58#endif
59
60
61/* These functions are passed to __libc_start_main by the startup code.
62 These get statically linked into each program. For dynamically linked
63 programs, this module will come from libc_nonshared.a and differs from
64 the libc.a module in that it doesn't call the preinit array. */
65
66
67void
68__libc_csu_init (int argc, char **argv, char **envp)
69{
70 /* For dynamically linked executables the preinit array is executed by
71 the dynamic linker (before initializing any shared object). */
72
73#ifndef LIBC_NONSHARED
74 /* For static executables, preinit happens right before init. */
75 {
76 const size_t size = __preinit_array_end - __preinit_array_start;
77 size_t i;
78 for (i = 0; i < size; i++)
79 (*__preinit_array_start [i]) (argc, argv, envp);
80 }
81#endif
82
83#if ELF_INITFINI
84 _init ();
85#endif
86
87 const size_t size = __init_array_end - __init_array_start;
88 for (size_t i = 0; i < size; i++)
89 (*__init_array_start [i]) (argc, argv, envp);
90}
91
92/* This function should not be used anymore. We run the executable's
93 destructor now just like any other. We cannot remove the function,
94 though. */
95void
96__libc_csu_fini (void)
97{
98#ifndef LIBC_NONSHARED
99 size_t i = __fini_array_end - __fini_array_start;
100 while (i-- > 0)
101 (*__fini_array_start [i]) ();
102
103# if ELF_INITFINI
104 _fini ();
105# endif
106#endif
107}
108