/* Compressed section support (intended for debug sections).
Copyright (C) 2008-2015 Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
#include "sysdep.h"
#include <zlib.h>
#include "bfd.h"
#include "libbfd.h"
#include "safe-ctype.h"
#define MAX_COMPRESSION_HEADER_SIZE 24
static bfd_boolean
decompress_contents (bfd_byte *compressed_buffer,
bfd_size_type compressed_size,
bfd_byte *uncompressed_buffer,
bfd_size_type uncompressed_size)
{
z_stream strm;
int rc;
/* It is possible the section consists of several compressed
buffers concatenated together, so we uncompress in a loop. */
/* PR 18313: The state field in the z_stream structure is supposed
to be invisible to the user (ie us), but some compilers will
still complain about it being used without initialisation. So
we first zero the entire z_stream structure and then set the fields
that we need. */
memset (& strm
, 0, sizeof strm
); strm.avail_in = compressed_size;
strm.next_in = (Bytef*) compressed_buffer;
strm.avail_out = uncompressed_size;
BFD_ASSERT (Z_OK == 0);
rc = inflateInit (&strm);
while (strm.avail_in > 0 && strm.avail_out > 0)
{
if (rc != Z_OK)
break;
strm.next_out = ((Bytef*) uncompressed_buffer
+ (uncompressed_size - strm.avail_out));
rc = inflate (&strm, Z_FINISH);
if (rc != Z_STREAM_END)
break;
rc = inflateReset (&strm);
}
rc |= inflateEnd (&strm);
return rc == Z_OK && strm.avail_out == 0;
}
/* Compress data of the size specified in @var{uncompressed_size}
and pointed to by @var{uncompressed_buffer} using zlib and store
as the contents field. This function assumes the contents
field was allocated using bfd_malloc() or equivalent.
Return the uncompressed size if the full section contents is
compressed successfully. Otherwise return 0. */
static bfd_size_type
bfd_compress_section_contents (bfd *abfd, sec_ptr sec,
bfd_byte *uncompressed_buffer,
bfd_size_type uncompressed_size)
{
uLong compressed_size;
bfd_byte *buffer;
bfd_size_type buffer_size;
bfd_boolean decompress;
int zlib_size = 0;
int orig_compression_header_size;
bfd_size_type orig_uncompressed_size;
int header_size = bfd_get_compression_header_size (abfd, NULL);
bfd_boolean compressed
= bfd_is_section_compressed_with_header (abfd, sec,
&orig_compression_header_size,
&orig_uncompressed_size);
/* Either ELF compression header or the 12-byte, "ZLIB" + 8-byte size,
overhead in .zdebug* section. */
if (!header_size)
header_size = 12;
if (compressed)
{
/* We shouldn't decompress unsupported compressed section. */
if (orig_compression_header_size < 0)
/* Different compression schemes. Just move the compressed section
contents to the right position. */
if (orig_compression_header_size == 0)
{
/* Convert it from .zdebug* section. Get the uncompressed
size first. We need to substract the 12-byte overhead in
.zdebug* section. Set orig_compression_header_size to
the 12-bye overhead. */
orig_compression_header_size = 12;
zlib_size = uncompressed_size - 12;
}
else
{
/* Convert it to .zdebug* section. */
zlib_size = uncompressed_size - orig_compression_header_size;
}
/* Add the header size. */
compressed_size = zlib_size + header_size;
}
else
compressed_size = compressBound (uncompressed_size) + header_size;
/* Uncompress if it leads to smaller size. */
if (compressed && compressed_size > orig_uncompressed_size)
{
decompress = TRUE;
buffer_size = orig_uncompressed_size;
}
else
{
decompress = FALSE;
buffer_size = compressed_size;
}
buffer = (bfd_byte *) bfd_alloc (abfd, buffer_size);
if (buffer == NULL)
return 0;
if (compressed)
{
sec->size = orig_uncompressed_size;
if (decompress)
{
if (!decompress_contents (uncompressed_buffer
+ orig_compression_header_size,
zlib_size, buffer, buffer_size))
{
bfd_set_error (bfd_error_bad_value);
bfd_release (abfd, buffer);
return 0;
}
free (uncompressed_buffer
); sec->contents = buffer;
sec->compress_status = COMPRESS_SECTION_DONE;
return orig_uncompressed_size;
}
else
{
bfd_update_compression_header (abfd, buffer, sec);
uncompressed_buffer + orig_compression_header_size,
zlib_size);
}
}
else
{
if (compress ((Bytef*) buffer + header_size,
&compressed_size,
(const Bytef*) uncompressed_buffer,
uncompressed_size) != Z_OK)
{
bfd_release (abfd, buffer);
bfd_set_error (bfd_error_bad_value);
return 0;
}
compressed_size += header_size;
/* PR binutils/18087: If compression didn't make the section smaller,
just keep it uncompressed. */
if (compressed_size < uncompressed_size)
bfd_update_compression_header (abfd, buffer, sec);
else
{
/* NOTE: There is a small memory leak here since
uncompressed_buffer is malloced and won't be freed. */
bfd_release (abfd, buffer);
sec->contents = uncompressed_buffer;
sec->compress_status = COMPRESS_SECTION_NONE;
return uncompressed_size;
}
}
free (uncompressed_buffer
); sec->contents = buffer;
sec->size = compressed_size;
sec->compress_status = COMPRESS_SECTION_DONE;
return uncompressed_size;
}
/*
FUNCTION
bfd_get_full_section_contents
SYNOPSIS
bfd_boolean bfd_get_full_section_contents
(bfd *abfd, asection *section, bfd_byte **ptr);
DESCRIPTION
Read all data from @var{section} in BFD @var{abfd}, decompress
if needed, and store in @var{*ptr}. If @var{*ptr} is NULL,
return @var{*ptr} with memory malloc'd by this function.
Return @code{TRUE} if the full section contents is retrieved
successfully. If the section has no contents then this function
returns @code{TRUE} but @var{*ptr} is set to NULL.
*/
bfd_boolean
bfd_get_full_section_contents (bfd *abfd, sec_ptr sec, bfd_byte **ptr)
{
bfd_size_type sz;
bfd_byte *p = *ptr;
bfd_boolean ret;
bfd_size_type save_size;
bfd_size_type save_rawsize;
bfd_byte *compressed_buffer;
unsigned int compression_header_size;
if (abfd->direction != write_direction && sec->rawsize != 0)
sz = sec->rawsize;
else
sz = sec->size;
if (sz == 0)
{
*ptr = NULL;
return TRUE;
}
switch (sec->compress_status)
{
case COMPRESS_SECTION_NONE:
if (p == NULL)
{
p = (bfd_byte *) bfd_malloc (sz);
if (p == NULL)
return FALSE;
}
if (!bfd_get_section_contents (abfd, sec, p, 0, sz))
{
if (*ptr != p)
return FALSE;
}
*ptr = p;
return TRUE;
case DECOMPRESS_SECTION_SIZED:
/* Read in the full compressed section contents. */
compressed_buffer = (bfd_byte *) bfd_malloc (sec->compressed_size);
if (compressed_buffer == NULL)
return FALSE;
save_rawsize = sec->rawsize;
save_size = sec->size;
/* Clear rawsize, set size to compressed size and set compress_status
to COMPRESS_SECTION_NONE. If the compressed size is bigger than
the uncompressed size, bfd_get_section_contents will fail. */
sec->rawsize = 0;
sec->size = sec->compressed_size;
sec->compress_status = COMPRESS_SECTION_NONE;
ret = bfd_get_section_contents (abfd, sec, compressed_buffer,
0, sec->compressed_size);
/* Restore rawsize and size. */
sec->rawsize = save_rawsize;
sec->size = save_size;
sec->compress_status = DECOMPRESS_SECTION_SIZED;
if (!ret)
goto fail_compressed;
if (p == NULL)
p = (bfd_byte *) bfd_malloc (sz);
if (p == NULL)
goto fail_compressed;
compression_header_size = bfd_get_compression_header_size (abfd, sec);
if (compression_header_size == 0)
/* Set header size to the zlib header size if it is a
SHF_COMPRESSED section. */
compression_header_size = 12;
if (!decompress_contents (compressed_buffer + compression_header_size,
sec->compressed_size, p, sz))
{
bfd_set_error (bfd_error_bad_value);
if (p != *ptr)
fail_compressed:
free (compressed_buffer
); return FALSE;
}
free (compressed_buffer
); *ptr = p;
return TRUE;
case COMPRESS_SECTION_DONE:
if (sec->contents == NULL)
return FALSE;
if (p == NULL)
{
p = (bfd_byte *) bfd_malloc (sz);
if (p == NULL)
return FALSE;
*ptr = p;
}
/* PR 17512; file: 5bc29788. */
if (p != sec->contents)
memcpy (p
, sec
->contents
, sz
); return TRUE;
default:
}
}
/*
FUNCTION
bfd_cache_section_contents
SYNOPSIS
void bfd_cache_section_contents
(asection *sec, void *contents);
DESCRIPTION
Stash @var(contents) so any following reads of @var(sec) do
not need to decompress again.
*/
void
bfd_cache_section_contents (asection *sec, void *contents)
{
if (sec->compress_status == DECOMPRESS_SECTION_SIZED)
sec->compress_status = COMPRESS_SECTION_DONE;
sec->contents = contents;
sec->flags |= SEC_IN_MEMORY;
}
/*
FUNCTION
bfd_is_section_compressed_with_header
SYNOPSIS
bfd_boolean bfd_is_section_compressed_with_header
(bfd *abfd, asection *section,
int *compression_header_size_p,
bfd_size_type *uncompressed_size_p);
DESCRIPTION
Return @code{TRUE} if @var{section} is compressed. Compression
header size is returned in @var{compression_header_size_p} and
uncompressed size is returned in @var{uncompressed_size_p}. If
compression is unsupported, compression header size is returned
with -1 and uncompressed size is returned with 0.
*/
bfd_boolean
bfd_is_section_compressed_with_header (bfd *abfd, sec_ptr sec,
int *compression_header_size_p,
bfd_size_type *uncompressed_size_p)
{
bfd_byte header[MAX_COMPRESSION_HEADER_SIZE];
int compression_header_size;
int header_size;
unsigned int saved = sec->compress_status;
bfd_boolean compressed;
compression_header_size = bfd_get_compression_header_size (abfd, sec);
if (compression_header_size > MAX_COMPRESSION_HEADER_SIZE)
header_size = compression_header_size ? compression_header_size : 12;
/* Don't decompress the section. */
sec->compress_status = COMPRESS_SECTION_NONE;
/* Read the header. */
if (bfd_get_section_contents (abfd, sec, header, 0, header_size))
{
if (compression_header_size == 0)
/* In this case, it should be "ZLIB" followed by the uncompressed
section size, 8 bytes in big-endian order. */
compressed = CONST_STRNEQ ((char*) header , "ZLIB");
else
compressed = TRUE;
}
else
compressed = FALSE;
*uncompressed_size_p = sec->size;
if (compressed)
{
if (compression_header_size != 0)
{
if (!bfd_check_compression_header (abfd, header, sec,
uncompressed_size_p))
compression_header_size = -1;
}
/* Check for the pathalogical case of a debug string section that
contains the string ZLIB.... as the first entry. We assume that
no uncompressed .debug_str section would ever be big enough to
have the first byte of its (big-endian) size be non-zero. */
else if (strcmp (sec
->name
, ".debug_str") == 0 && ISPRINT (header[4]))
compressed = FALSE;
else
*uncompressed_size_p = bfd_getb64 (header + 4);
}
/* Restore compress_status. */
sec->compress_status = saved;
*compression_header_size_p = compression_header_size;
return compressed;
}
/*
FUNCTION
bfd_is_section_compressed
SYNOPSIS
bfd_boolean bfd_is_section_compressed
(bfd *abfd, asection *section);
DESCRIPTION
Return @code{TRUE} if @var{section} is compressed.
*/
bfd_boolean
bfd_is_section_compressed (bfd *abfd, sec_ptr sec)
{
int compression_header_size;
bfd_size_type uncompressed_size;
return (bfd_is_section_compressed_with_header (abfd, sec,
&compression_header_size,
&uncompressed_size)
&& compression_header_size >= 0
&& uncompressed_size > 0);
}
/*
FUNCTION
bfd_init_section_decompress_status
SYNOPSIS
bfd_boolean bfd_init_section_decompress_status
(bfd *abfd, asection *section);
DESCRIPTION
Record compressed section size, update section size with
decompressed size and set compress_status to
DECOMPRESS_SECTION_SIZED.
Return @code{FALSE} if the section is not a valid compressed
section. Otherwise, return @code{TRUE}.
*/
bfd_boolean
bfd_init_section_decompress_status (bfd *abfd, sec_ptr sec)
{
bfd_byte header[MAX_COMPRESSION_HEADER_SIZE];
int compression_header_size;
int header_size;
bfd_size_type uncompressed_size;
compression_header_size = bfd_get_compression_header_size (abfd, sec);
if (compression_header_size > MAX_COMPRESSION_HEADER_SIZE)
header_size = compression_header_size ? compression_header_size : 12;
/* Read the header. */
if (sec->rawsize != 0
|| sec->contents != NULL
|| sec->compress_status != COMPRESS_SECTION_NONE
|| !bfd_get_section_contents (abfd, sec, header, 0, header_size))
{
bfd_set_error (bfd_error_invalid_operation);
return FALSE;
}
if (compression_header_size == 0)
{
/* In this case, it should be "ZLIB" followed by the uncompressed
section size, 8 bytes in big-endian order. */
if (! CONST_STRNEQ ((char*) header, "ZLIB"))
{
bfd_set_error (bfd_error_wrong_format);
return FALSE;
}
uncompressed_size = bfd_getb64 (header + 4);
}
else if (!bfd_check_compression_header (abfd, header, sec,
&uncompressed_size))
{
bfd_set_error (bfd_error_wrong_format);
return FALSE;
}
sec->compressed_size = sec->size;
sec->size = uncompressed_size;
sec->compress_status = DECOMPRESS_SECTION_SIZED;
return TRUE;
}
/*
FUNCTION
bfd_init_section_compress_status
SYNOPSIS
bfd_boolean bfd_init_section_compress_status
(bfd *abfd, asection *section);
DESCRIPTION
If open for read, compress section, update section size with
compressed size and set compress_status to COMPRESS_SECTION_DONE.
Return @code{FALSE} if the section is not a valid compressed
section. Otherwise, return @code{TRUE}.
*/
bfd_boolean
bfd_init_section_compress_status (bfd *abfd, sec_ptr sec)
{
bfd_size_type uncompressed_size;
bfd_byte *uncompressed_buffer;
bfd_boolean ret;
/* Error if not opened for read. */
if (abfd->direction != read_direction
|| sec->size == 0
|| sec->rawsize != 0
|| sec->contents != NULL
|| sec->compress_status != COMPRESS_SECTION_NONE)
{
bfd_set_error (bfd_error_invalid_operation);
return FALSE;
}
/* Read in the full section contents and compress it. */
uncompressed_size = sec->size;
uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
if (!bfd_get_section_contents (abfd, sec, uncompressed_buffer,
0, uncompressed_size))
ret = FALSE;
else
{
uncompressed_size = bfd_compress_section_contents (abfd, sec,
uncompressed_buffer,
uncompressed_size);
ret = uncompressed_size != 0;
}
return ret;
}
/*
FUNCTION
bfd_compress_section
SYNOPSIS
bfd_boolean bfd_compress_section
(bfd *abfd, asection *section, bfd_byte *uncompressed_buffer);
DESCRIPTION
If open for write, compress section, update section size with
compressed size and set compress_status to COMPRESS_SECTION_DONE.
Return @code{FALSE} if compression fail. Otherwise, return
@code{TRUE}.
*/
bfd_boolean
bfd_compress_section (bfd *abfd, sec_ptr sec, bfd_byte *uncompressed_buffer)
{
bfd_size_type uncompressed_size = sec->size;
/* Error if not opened for write. */
if (abfd->direction != write_direction
|| uncompressed_size == 0
|| uncompressed_buffer == NULL
|| sec->contents != NULL
|| sec->compressed_size != 0
|| sec->compress_status != COMPRESS_SECTION_NONE)
{
bfd_set_error (bfd_error_invalid_operation);
return FALSE;
}
/* Compress it. */
return bfd_compress_section_contents (abfd, sec, uncompressed_buffer,
uncompressed_size) != 0;
}