| /* Linux kernel image support for libdwfl. |
| Copyright (C) 2009 Red Hat, Inc. |
| This file is part of Red Hat elfutils. |
| |
| Red Hat elfutils 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; version 2 of the License. |
| |
| Red Hat 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 a copy of the GNU General Public License along |
| with Red Hat elfutils; if not, write to the Free Software Foundation, |
| Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. |
| |
| In addition, as a special exception, Red Hat, Inc. gives You the |
| additional right to link the code of Red Hat elfutils with code licensed |
| under any Open Source Initiative certified open source license |
| (http://www.opensource.org/licenses/index.php) which requires the |
| distribution of source code with any binary distribution and to |
| distribute linked combinations of the two. Non-GPL Code permitted under |
| this exception must only link to the code of Red Hat elfutils through |
| those well defined interfaces identified in the file named EXCEPTION |
| found in the source code files (the "Approved Interfaces"). The files |
| of Non-GPL Code may instantiate templates or use macros or inline |
| functions from the Approved Interfaces without causing the resulting |
| work to be covered by the GNU General Public License. Only Red Hat, |
| Inc. may make changes or additions to the list of Approved Interfaces. |
| Red Hat's grant of this exception is conditioned upon your not adding |
| any new exceptions. If you wish to add a new Approved Interface or |
| exception, please contact Red Hat. You must obey the GNU General Public |
| License in all respects for all of the Red Hat elfutils code and other |
| code used in conjunction with Red Hat elfutils except the Non-GPL Code |
| covered by this exception. If you modify this file, you may extend this |
| exception to your version of the file, but you are not obligated to do |
| so. If you do not wish to provide this exception without modification, |
| you must delete this exception statement from your version and license |
| this file solely under the GPL without exception. |
| |
| Red Hat elfutils is an included package of the Open Invention Network. |
| An included package of the Open Invention Network is a package for which |
| Open Invention Network licensees cross-license their patents. No patent |
| license is granted, either expressly or impliedly, by designation as an |
| included package. Should you wish to participate in the Open Invention |
| Network licensing program, please visit www.openinventionnetwork.com |
| <http://www.openinventionnetwork.com>. */ |
| |
| #include "libdwflP.h" |
| #include "system.h" |
| |
| #include <unistd.h> |
| #include <endian.h> |
| |
| #if BYTE_ORDER == LITTLE_ENDIAN |
| # define LE16(x) (x) |
| # define LE32(x) (x) |
| #else |
| # define LE16(x) bswap_16 (x) |
| # define LE32(x) bswap_32 (x) |
| #endif |
| |
| /* See Documentation/x86/boot.txt in Linux kernel sources |
| for an explanation of these format details. */ |
| |
| #define MAGIC1 0xaa55 |
| #define MAGIC2 0x53726448 /* "HdrS" little-endian */ |
| #define MIN_VERSION 0x0208 |
| |
| #define H_START (H_SETUP_SECTS & -4) |
| #define H_SETUP_SECTS 0x1f1 |
| #define H_MAGIC1 0x1fe |
| #define H_MAGIC2 0x202 |
| #define H_VERSION 0x206 |
| #define H_PAYLOAD_OFFSET 0x248 |
| #define H_PAYLOAD_LENGTH 0x24c |
| #define H_END 0x250 |
| #define H_READ_SIZE (H_END - H_START) |
| |
| Dwfl_Error |
| internal_function |
| __libdw_image_header (int fd, off64_t *start_offset, |
| void *mapped, size_t mapped_size) |
| { |
| if (likely (mapped_size > H_END)) |
| { |
| const void *header = mapped; |
| char header_buffer[H_READ_SIZE]; |
| if (header == NULL) |
| { |
| ssize_t n = pread_retry (fd, header_buffer, H_READ_SIZE, |
| *start_offset + H_START); |
| if (n < 0) |
| return DWFL_E_ERRNO; |
| if (n < H_READ_SIZE) |
| return DWFL_E_BADELF; |
| |
| header = header_buffer - H_START; |
| } |
| |
| if (*(uint16_t *) (header + H_MAGIC1) == LE16 (MAGIC1) |
| && *(uint32_t *) (header + H_MAGIC2) == LE32 (MAGIC2) |
| && LE16 (*(uint16_t *) (header + H_VERSION)) >= MIN_VERSION) |
| { |
| /* The magic numbers match and the version field is sufficient. |
| Extract the payload bounds. */ |
| |
| uint32_t offset = LE32 (*(uint32_t *) (header + H_PAYLOAD_OFFSET)); |
| uint32_t length = LE32 (*(uint32_t *) (header + H_PAYLOAD_LENGTH)); |
| |
| offset += ((*(uint8_t *) (header + H_SETUP_SECTS) ?: 4) + 1) * 512; |
| |
| if (offset > H_END && offset < mapped_size |
| && mapped_size - length >= offset) |
| { |
| /* It looks kosher. Use it! */ |
| *start_offset += offset; |
| return DWFL_E_NOERROR; |
| } |
| } |
| } |
| return DWFL_E_BADELF; |
| } |