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/* Decompression support for libdwfl: zlib (gzip), bzlib (bzip2) or lzma (xz).
Copyright (C) 2009, 2016 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
it under the terms of either
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at
your option) any later version
or
* the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at
your option) any later version
or both in parallel, as here.
elfutils is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received copies of the GNU General Public License and
the GNU Lesser General Public License along with this program. If
not, see <http://www.gnu.org/licenses/>. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "../libelf/libelfP.h"
#undef _
#include "libdwflP.h"
#include <unistd.h>
#if !USE_BZLIB
# define __libdw_bunzip2(...) DWFL_E_BADELF
#endif
#if !USE_LZMA
# define __libdw_unlzma(...) DWFL_E_BADELF
#endif
/* Consumes and replaces *ELF only on success. */
static Dwfl_Error
decompress (int fd __attribute__ ((unused)), Elf **elf)
{
Dwfl_Error error = DWFL_E_BADELF;
void *buffer = NULL;
size_t size = 0;
const off_t offset = (*elf)->start_offset;
void *const mapped = ((*elf)->map_address == NULL ? NULL
: (*elf)->map_address + offset);
const size_t mapped_size = (*elf)->maximum_size;
if (mapped_size == 0)
return error;
error = __libdw_gunzip (fd, offset, mapped, mapped_size, &buffer, &size);
if (error == DWFL_E_BADELF)
error = __libdw_bunzip2 (fd, offset, mapped, mapped_size, &buffer, &size);
if (error == DWFL_E_BADELF)
error = __libdw_unlzma (fd, offset, mapped, mapped_size, &buffer, &size);
if (error == DWFL_E_NOERROR)
{
if (unlikely (size == 0))
{
error = DWFL_E_BADELF;
free (buffer);
}
else
{
Elf *memelf = elf_memory (buffer, size);
if (memelf == NULL)
{
error = DWFL_E_LIBELF;
free (buffer);
}
else
{
memelf->flags |= ELF_F_MALLOCED;
elf_end (*elf);
*elf = memelf;
}
}
}
else
free (buffer);
return error;
}
static Dwfl_Error
what_kind (int fd, Elf **elfp, Elf_Kind *kind, bool *close_fd)
{
Dwfl_Error error = DWFL_E_NOERROR;
*kind = elf_kind (*elfp);
if (unlikely (*kind == ELF_K_NONE))
{
if (unlikely (*elfp == NULL))
error = DWFL_E_LIBELF;
else
{
error = decompress (fd, elfp);
if (error == DWFL_E_NOERROR)
{
*close_fd = true;
*kind = elf_kind (*elfp);
}
}
}
return error;
}
Dwfl_Error internal_function
__libdw_open_file (int *fdp, Elf **elfp, bool close_on_fail, bool archive_ok)
{
bool close_fd = false;
Elf *elf = elf_begin (*fdp, ELF_C_READ_MMAP_PRIVATE, NULL);
Elf_Kind kind;
Dwfl_Error error = what_kind (*fdp, &elf, &kind, &close_fd);
if (error == DWFL_E_BADELF)
{
/* It's not an ELF file or a compressed file.
See if it's an image with a header preceding the real file. */
off_t offset = elf->start_offset;
error = __libdw_image_header (*fdp, &offset,
(elf->map_address == NULL ? NULL
: elf->map_address + offset),
elf->maximum_size);
if (error == DWFL_E_NOERROR)
{
/* Pure evil. libelf needs some better interfaces. */
elf->kind = ELF_K_AR;
elf->state.ar.elf_ar_hdr.ar_name = "libdwfl is faking you out";
elf->state.ar.elf_ar_hdr.ar_size = elf->maximum_size - offset;
elf->state.ar.offset = offset - sizeof (struct ar_hdr);
Elf *subelf = elf_begin (-1, ELF_C_READ_MMAP_PRIVATE, elf);
elf->kind = ELF_K_NONE;
if (unlikely (subelf == NULL))
error = DWFL_E_LIBELF;
else
{
subelf->parent = NULL;
subelf->flags |= elf->flags & (ELF_F_MMAPPED | ELF_F_MALLOCED);
elf->flags &= ~(ELF_F_MMAPPED | ELF_F_MALLOCED);
elf_end (elf);
elf = subelf;
error = what_kind (*fdp, &elf, &kind, &close_fd);
}
}
}
if (error == DWFL_E_NOERROR
&& kind != ELF_K_ELF
&& !(archive_ok && kind == ELF_K_AR))
error = DWFL_E_BADELF;
if (error != DWFL_E_NOERROR)
{
elf_end (elf);
elf = NULL;
}
if (error == DWFL_E_NOERROR ? close_fd : close_on_fail)
{
close (*fdp);
*fdp = -1;
}
*elfp = elf;
return error;
}
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