freebsd-src/contrib/elftoolchain/libelf/gelf_chdr.c
Ed Maste 573456a931 libelf: add compression header support
GNU and Oracle libelf implementations added support for section
compression, intended to reduce the size of DWARF debug info (which
might be an order of magnitude larger than the code).

There are two compressed ELF section formats:

1. Old GNU - sections are renmaed to start with 'z'.  Section contains
   a magic number, uncompressed size, and compressed data.

2. Oracle and New GNU - compressed sections use the SHF_COMPRESSED flag.
   The compression header contains the compression type, uncompressed
   size, and uncompressed alignment.

The second style is preferred and this change implements only that one.

Submitted by:	Tiger Gao <tig@FreeBSDFoundation.org>
Reviewed by:	markj
MFC after:	2 weeks
Relnotes:	Yes
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D24566
2020-10-23 16:35:23 +00:00

83 lines
2.3 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2020 The FreeBSD Foundation
*
* This software was developed by Tiger Gao under sponsorship from
* the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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 AUTHOR 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 AUTHOR 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.
*/
#include <assert.h>
#include <gelf.h>
#include <libelf.h>
#include <limits.h>
#include <stdint.h>
#include "_libelf.h"
Elf32_Chdr *
elf32_getchdr(Elf_Scn *s)
{
return (_libelf_getchdr(s, ELFCLASS32));
}
Elf64_Chdr *
elf64_getchdr(Elf_Scn *s)
{
return (_libelf_getchdr(s, ELFCLASS64));
}
GElf_Chdr *
gelf_getchdr(Elf_Scn *s, GElf_Chdr *d)
{
int ec;
void *ch;
Elf32_Chdr *ch32;
Elf64_Chdr *ch64;
if (d == NULL) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
if ((ch = _libelf_getchdr(s, ELFCLASSNONE)) == NULL)
return (NULL);
ec = s->s_elf->e_class;
assert(ec == ELFCLASS32 || ec == ELFCLASS64);
if (ec == ELFCLASS32) {
ch32 = (Elf32_Chdr *)ch;
d->ch_type = (Elf64_Word)ch32->ch_type;
d->ch_size = (Elf64_Xword)ch32->ch_size;
d->ch_addralign = (Elf64_Xword)ch32->ch_addralign;
} else {
ch64 = (Elf64_Chdr *)ch;
*d = *ch64;
}
return (d);
}