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/****************************************************************************
* binfmt/libelf/libelf_init.c
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/stat.h>
#include <stdint.h>
#include <string.h>
#include <fcntl.h>
#include <elf32.h>
#include <debug.h>
#include <errno.h>
#include <nuttx/binfmt/elf.h>
#include "libelf.h"
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
/* CONFIG_DEBUG, CONFIG_DEBUG_VERBOSE, and CONFIG_DEBUG_BINFMT have to be
* defined or CONFIG_ELF_DUMPBUFFER does nothing.
*/
#if !defined(CONFIG_DEBUG_VERBOSE) || !defined (CONFIG_DEBUG_BINFMT)
# undef CONFIG_ELF_DUMPBUFFER
#endif
#ifdef CONFIG_ELF_DUMPBUFFER
# define elf_dumpbuffer(m,b,n) bvdbgdumpbuffer(m,b,n)
#else
# define elf_dumpbuffer(m,b,n)
#endif
/****************************************************************************
* Private Constant Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: elf_filelen
*
* Description:
* Get the size of the ELF file
*
* Returned Value:
* 0 (OK) is returned on success and a negated errno is returned on
* failure.
*
****************************************************************************/
static inline int elf_filelen(FAR struct elf_loadinfo_s *loadinfo,
FAR const char *filename)
{
struct stat buf;
int ret;
/* Get the file stats */
ret = stat(filename, &buf);
if (ret < 0)
{
int errval = errno;
bdbg("Failed to fstat file: %d\n", errval);
return -errval;
}
/* Verify that it is a regular file */
if (!S_ISREG(buf.st_mode))
{
bdbg("Not a regular file. mode: %d\n", buf.st_mode);
return -ENOENT;
}
/* TODO: Verify that the file is readable. Not really important because
* we will detect this when we try to open the file read-only.
*/
/* Return the size of the file in the loadinfo structure */
loadinfo->filelen = buf.st_size;
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: elf_init
*
* Description:
* This function is called to configure the library to process an ELF
* program binary.
*
* Returned Value:
* 0 (OK) is returned on success and a negated errno is returned on
* failure.
*
****************************************************************************/
int elf_init(FAR const char *filename, FAR struct elf_loadinfo_s *loadinfo)
{
int ret;
bvdbg("filename: %s loadinfo: %p\n", filename, loadinfo);
/* Clear the load info structure */
memset(loadinfo, 0, sizeof(struct elf_loadinfo_s));
/* Get the length of the file. */
ret = elf_filelen(loadinfo, filename);
if (ret < 0)
{
bdbg("elf_filelen failed: %d\n", ret);
return ret;
}
/* Open the binary file for reading (only) */
loadinfo->filfd = open(filename, O_RDONLY);
if (loadinfo->filfd < 0)
{
int errval = errno;
bdbg("Failed to open ELF binary %s: %d\n", filename, errval);
return -errval;
}
/* Read the ELF ehdr from offset 0 */
ret = elf_read(loadinfo, (FAR uint8_t*)&loadinfo->ehdr, sizeof(Elf32_Ehdr), 0);
if (ret < 0)
{
bdbg("Failed to read ELF header: %d\n", ret);
return ret;
}
elf_dumpbuffer("ELF header", (FAR const uint8_t*)&loadinfo->ehdr, sizeof(Elf32_Ehdr));
/* Verify the ELF header */
ret = elf_verifyheader(&loadinfo->ehdr);
if (ret <0)
{
/* This may not be an error because we will be called to attempt loading
* EVERY binary. If elf_verifyheader() does not recognize the ELF header,
* it will -ENOEXEC whcih simply informs the system that the file is not an
* ELF file. elf_verifyheader() will return other errors if the ELF header
* is not correctly formed.
*/
bdbg("Bad ELF header: %d\n", ret);
return ret;
}
return OK;
}
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