285 lines
8.2 KiB
C
285 lines
8.2 KiB
C
/****************************************************************************
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* binfmt/libelf/libelf_sections.c
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*
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* Copyright (C) 2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/binfmt/elf.h>
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#include "libelf.h"
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/****************************************************************************
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* Pre-Processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Constant Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: elf_sectname
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*
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* Description:
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* Get the symbol name in loadinfo->iobuffer[].
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*
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* Returned Value:
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* 0 (OK) is returned on success and a negated errno is returned on
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* failure.
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*
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****************************************************************************/
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static inline int elf_sectname(FAR struct elf_loadinfo_s *loadinfo,
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FAR const Elf32_Shdr *shdr)
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{
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FAR Elf32_Shdr *shstr;
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FAR uint8_t *buffer;
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off_t offset;
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size_t readlen;
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size_t bytesread;
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int shstrndx;
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int ret;
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/* Get the section header table index of the entry associated with the
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* section name string table. If the file has no section name string table,
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* this member holds the value SH_UNDEF.
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*/
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shstrndx = loadinfo->ehdr.e_shstrndx;
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if (shstrndx == SHN_UNDEF)
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{
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bdbg("No section header string table\n");
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return -EINVAL;
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}
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/* Get the section name string table section header */
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shstr = &loadinfo->shdr[shstrndx];
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/* Get the file offset to the string that is the name of the section. This
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* is the sum of:
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*
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* shstr->sh_offset: The file offset to the first byte of the section
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* header string table data.
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* shdr->sh_name: The offset to the name of the section in the section
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* name table
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*/
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offset = shstr->sh_offset + shdr->sh_name;
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/* Loop until we get the entire section name into memory */
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buffer = loadinfo->iobuffer;
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bytesread = 0;
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for (;;)
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{
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/* Get the number of bytes to read */
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readlen = loadinfo->buflen - bytesread;
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if (offset + readlen > loadinfo->filelen)
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{
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readlen = loadinfo->filelen - offset;
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if (readlen <= 0)
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{
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bdbg("At end of file\n");
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return -EINVAL;
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}
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}
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/* Read that number of bytes into the array */
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buffer = &loadinfo->iobuffer[bytesread];
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ret = elf_read(loadinfo, buffer, readlen, offset);
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if (ret < 0)
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{
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bdbg("Failed to read section name\n");
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return ret;
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}
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bytesread += readlen;
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/* Did we read the NUL terminator? */
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if (memchr(buffer, '\0', readlen) != NULL)
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{
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/* Yes, the buffer contains a NUL terminator. */
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return OK;
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}
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/* No.. then we have to read more */
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ret = elf_reallocbuffer(loadinfo, CONFIG_ELF_BUFFERINCR);
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if (ret < 0)
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{
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bdbg("elf_reallocbuffer failed: %d\n", ret);
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return ret;
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}
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}
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/* We will not get here */
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return OK;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: elf_loadshdrs
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*
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* Description:
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* Loads section headers into memory.
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*
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* Returned Value:
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* 0 (OK) is returned on success and a negated errno is returned on
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* failure.
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*
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****************************************************************************/
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int elf_loadshdrs(FAR struct elf_loadinfo_s *loadinfo)
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{
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size_t shdrsize;
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int ret;
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DEBUGASSERT(loadinfo->shdr == NULL);
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/* Verify that there are sections */
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if (loadinfo->ehdr.e_shnum < 1)
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{
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bdbg("No sections(?)\n");
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return -EINVAL;
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}
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/* Get the total size of the section header table */
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shdrsize = (size_t)loadinfo->ehdr.e_shentsize * (size_t)loadinfo->ehdr.e_shnum;
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if(loadinfo->ehdr.e_shoff + shdrsize > loadinfo->filelen)
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{
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bdbg("Insufficent space in file for section header table\n");
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return -ESPIPE;
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}
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/* Allocate memory to hold a working copy of the sector header table */
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loadinfo->shdr = (FAR Elf32_Shdr*)kmalloc(shdrsize);
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if (!loadinfo->shdr)
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{
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bdbg("Failed to allocate the section header table. Size: %ld\n", (long)shdrsize);
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return -ENOMEM;
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}
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/* Read the section header table into memory */
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ret = elf_read(loadinfo, (FAR uint8_t*)loadinfo->shdr, shdrsize, loadinfo->ehdr.e_shoff);
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if (ret < 0)
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{
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bdbg("Failed to read section header table: %d\n", ret);
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}
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return ret;
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}
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/****************************************************************************
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* Name: elf_findsection
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*
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* Description:
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* A section by its name.
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*
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* Input Parameters:
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* loadinfo - Load state information
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* sectname - Name of the section to find
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*
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* Returned Value:
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* On success, the index to the section is returned; A negated errno value
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* is returned on failure.
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*
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****************************************************************************/
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int elf_findsection(FAR struct elf_loadinfo_s *loadinfo,
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FAR const char *sectname)
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{
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FAR const Elf32_Shdr *shdr;
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int ret;
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int i;
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/* Search through the shdr[] array in loadinfo for a section named 'sectname' */
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for (i = 0; i < loadinfo->ehdr.e_shnum; i++)
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{
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/* Get the name of this section */
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shdr = &loadinfo->shdr[i];
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ret = elf_sectname(loadinfo, shdr);
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if (ret < 0)
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{
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bdbg("elf_sectname failed: %d\n", ret);
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return ret;
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}
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/* Check if the name of this section is 'sectname' */
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bvdbg("%d. Comparing \"%s\" and .\"%s\"\n",
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i, loadinfo->iobuffer, sectname);
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if (strcmp((FAR const char *)loadinfo->iobuffer, sectname) == 0)
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{
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/* We found it... return the index */
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return i;
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}
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}
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/* We failed to find a section with this name. */
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return -ENOENT;
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}
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