/****************************************************************************
* binfmt/libelf/libelf_sections.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 <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/binfmt/elf.h>
#include "libelf.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Constant Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: elf_sectname
*
* Description:
* Get the symbol name in loadinfo->iobuffer[].
*
* Returned Value:
* 0 (OK) is returned on success and a negated errno is returned on
* failure.
*
****************************************************************************/
static inline int elf_sectname(FAR struct elf_loadinfo_s *loadinfo,
FAR const Elf32_Shdr *shdr)
{
FAR Elf32_Shdr *shstr;
FAR uint8_t *buffer;
off_t offset;
size_t readlen;
size_t bytesread;
int shstrndx;
int ret;
/* Get the section header table index of the entry associated with the
* section name string table. If the file has no section name string table,
* this member holds the value SH_UNDEF.
*/
shstrndx = loadinfo->ehdr.e_shstrndx;
if (shstrndx == SHN_UNDEF)
{
berr("No section header string table\n");
return -EINVAL;
}
/* Get the section name string table section header */
shstr = &loadinfo->shdr[shstrndx];
/* Get the file offset to the string that is the name of the section. This
* is the sum of:
*
* shstr->sh_offset: The file offset to the first byte of the section
* header string table data.
* shdr->sh_name: The offset to the name of the section in the section
* name table
*/
offset = shstr->sh_offset + shdr->sh_name;
/* Loop until we get the entire section name into memory */
buffer = loadinfo->iobuffer;
bytesread = 0;
for (; ; )
{
/* Get the number of bytes to read */
readlen = loadinfo->buflen - bytesread;
if (offset + readlen > loadinfo->filelen)
{
if (loadinfo->filelen <= offset)
{
berr("At end of file\n");
return -EINVAL;
}
readlen = loadinfo->filelen - offset;
}
/* Read that number of bytes into the array */
buffer = &loadinfo->iobuffer[bytesread];
ret = elf_read(loadinfo, buffer, readlen, offset);
if (ret < 0)
{
berr("Failed to read section name\n");
return ret;
}
bytesread += readlen;
/* Did we read the NUL terminator? */
if (memchr(buffer, '\0', readlen) != NULL)
{
/* Yes, the buffer contains a NUL terminator. */
return OK;
}
/* No.. then we have to read more */
ret = elf_reallocbuffer(loadinfo, CONFIG_ELF_BUFFERINCR);
if (ret < 0)
{
berr("elf_reallocbuffer failed: %d\n", ret);
return ret;
}
}
/* We will not get here */
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: elf_loadshdrs
*
* Description:
* Loads section headers into memory.
*
* Returned Value:
* 0 (OK) is returned on success and a negated errno is returned on
* failure.
*
****************************************************************************/
int elf_loadshdrs(FAR struct elf_loadinfo_s *loadinfo)
{
size_t shdrsize;
int ret;
DEBUGASSERT(loadinfo->shdr == NULL);
/* Verify that there are sections */
if (loadinfo->ehdr.e_shnum < 1)
{
berr("No sections(?)\n");
return -EINVAL;
}
/* Get the total size of the section header table */
shdrsize = (size_t)loadinfo->ehdr.e_shentsize * (size_t)loadinfo->ehdr.e_shnum;
if (loadinfo->ehdr.e_shoff + shdrsize > loadinfo->filelen)
{
berr("Insufficent space in file for section header table\n");
return -ESPIPE;
}
/* Allocate memory to hold a working copy of the sector header table */
loadinfo->shdr = (FAR FAR Elf32_Shdr *)kmm_malloc(shdrsize);
if (!loadinfo->shdr)
{
berr("Failed to allocate the section header table. Size: %ld\n",
(long)shdrsize);
return -ENOMEM;
}
/* Read the section header table into memory */
ret = elf_read(loadinfo, (FAR uint8_t *)loadinfo->shdr, shdrsize,
loadinfo->ehdr.e_shoff);
if (ret < 0)
{
berr("Failed to read section header table: %d\n", ret);
}
return ret;
}
/****************************************************************************
* Name: elf_findsection
*
* Description:
* A section by its name.
*
* Input Parameters:
* loadinfo - Load state information
* sectname - Name of the section to find
*
* Returned Value:
* On success, the index to the section is returned; A negated errno value
* is returned on failure.
*
****************************************************************************/
int elf_findsection(FAR struct elf_loadinfo_s *loadinfo,
FAR const char *sectname)
{
FAR const Elf32_Shdr *shdr;
int ret;
int i;
/* Search through the shdr[] array in loadinfo for a section named 'sectname' */
for (i = 0; i < loadinfo->ehdr.e_shnum; i++)
{
/* Get the name of this section */
shdr = &loadinfo->shdr[i];
ret = elf_sectname(loadinfo, shdr);
if (ret < 0)
{
berr("elf_sectname failed: %d\n", ret);
return ret;
}
/* Check if the name of this section is 'sectname' */
binfo("%d. Comparing \"%s\" and .\"%s\"\n",
i, loadinfo->iobuffer, sectname);
if (strcmp((FAR const char *)loadinfo->iobuffer, sectname) == 0)
{
/* We found it... return the index */
return i;
}
}
/* We failed to find a section with this name. */
return -ENOENT;
}