1/* Special .init and .fini section support.
2 Copyright (C) 1997-2020 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 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 The GNU C Library is distributed in the hope that it will be useful,
20 but WITHOUT ANY WARRANTY; without even the implied warranty of
21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 Lesser General Public License for more details.
23
24 You should have received a copy of the GNU Lesser General Public
25 License along with the GNU C Library; if not, see
26 <https://www.gnu.org/licenses/>. */
27
28/* Define an ELF note identifying the operating-system ABI that the
29 executable was created for. The ELF note information identifies a
30 particular OS or coordinated development effort within which the
31 ELF header's e_machine value plus (for dynamically linked programs)
32 the PT_INTERP dynamic linker name and DT_NEEDED shared library
33 names fully identify the runtime environment required by an
34 executable.
35
36 The general format of ELF notes is as follows.
37 Offsets and lengths are bytes or (parenthetical references) to the
38 values in other fields.
39
40offset length contents
410 4 length of name
424 4 length of data
438 4 note type
4412 (0) vendor name
45 - null-terminated ASCII string, padded to 4-byte alignment
4612+(0) (4) note data,
47
48 The GNU project and cooperating development efforts (including the
49 Linux community) use note type 1 and a vendor name string of "GNU"
50 for a note descriptor that indicates ABI requirements. The note data
51 is four 32-bit words. The first of these is an operating system
52 number (0=Linux, 1=Hurd, 2=Solaris, ...) and the remaining three
53 identify the earliest release of that OS that supports this ABI.
54 See abi-tags (top level) for details. */
55
56#include <link.h>
57#include <stdint.h>
58#include <config.h>
59#include <abi-tag.h> /* OS-specific ABI tag value */
60
61/* The linker (GNU ld 2.8 and later) recognizes an allocated section whose
62 name begins with `.note' and creates a PT_NOTE program header entry
63 pointing at it. */
64
65__attribute__ ((used, aligned (4), section (".note.ABI-tag")))
66static const struct
67{
68 ElfW(Nhdr) nhdr;
69 char name[4];
70 int32_t desc[4];
71} __abi_tag = {
72 { .n_namesz = sizeof __abi_tag.name,
73 .n_descsz = sizeof __abi_tag.desc,
74 .n_type = 1 },
75 "GNU",
76 { __ABI_TAG_OS, __ABI_TAG_VERSION }
77};
78