forked from Archive/PX4-Autopilot
307 lines
9.2 KiB
C
307 lines
9.2 KiB
C
/****************************************************************************
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* binfmt/libelf/libelf_bind.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 <stdint.h>
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#include <string.h>
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#include <elf32.h>
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#include <errno.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/binfmt/elf.h>
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#include <nuttx/binfmt/symtab.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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/* CONFIG_DEBUG, CONFIG_DEBUG_VERBOSE, and CONFIG_DEBUG_BINFMT have to be
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* defined or CONFIG_ELF_DUMPBUFFER does nothing.
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*/
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#if !defined(CONFIG_DEBUG_VERBOSE) || !defined (CONFIG_DEBUG_BINFMT)
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# undef CONFIG_ELF_DUMPBUFFER
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#endif
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#ifndef CONFIG_ELF_BUFFERSIZE
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# define CONFIG_ELF_BUFFERSIZE 128
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#endif
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#ifdef CONFIG_ELF_DUMPBUFFER
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# define elf_dumpbuffer(m,b,n) bvdbgdumpbuffer(m,b,n)
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#else
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# define elf_dumpbuffer(m,b,n)
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#endif
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/****************************************************************************
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* Private 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_readsym
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*
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* Description:
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* Read the ELFT symbol structure at the specfied index into memory.
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*
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****************************************************************************/
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static inline int elf_readrel(FAR struct elf_loadinfo_s *loadinfo,
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FAR const Elf32_Shdr *relsec,
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int index, FAR Elf32_Rel *rel)
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{
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off_t offset;
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/* Verify that the symbol table index lies within symbol table */
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if (index < 0 || index > (relsec->sh_size / sizeof(Elf32_Rel)))
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{
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bdbg("Bad relocation symbol index: %d\n", index);
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return -EINVAL;
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}
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/* Get the file offset to the symbol table entry */
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offset = relsec->sh_offset + sizeof(Elf32_Rel) * index;
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/* And, finally, read the symbol table entry into memory */
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return elf_read(loadinfo, (FAR uint8_t*)rel, sizeof(Elf32_Rel), offset);
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}
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/****************************************************************************
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* Name: elf_relocate and elf_relocateadd
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*
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* Description:
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* Perform all relocations associated with a section.
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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 int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx,
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FAR const struct symtab_s *exports, int nexports)
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{
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FAR Elf32_Shdr *relsec = &loadinfo->shdr[relidx];
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FAR Elf32_Shdr *dstsec = &loadinfo->shdr[relsec->sh_info];
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Elf32_Rel rel;
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Elf32_Sym sym;
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uintptr_t addr;
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int symidx;
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int ret;
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int i;
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/* Examine each relocation in the section. 'relsec' is the section
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* containing the relations. 'dstsec' is the section containing the data
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* to be relocated.
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*/
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for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++)
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{
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/* Read the relocation entry into memory */
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ret = elf_readrel(loadinfo, relsec, i, &rel);
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if (ret < 0)
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{
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bdbg("Section %d reloc %d: Failed to read relocation entry: %d\n",
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relidx, i, ret);
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return ret;
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}
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/* Get the symbol table index for the relocation. This is contained
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* in a bit-field within the r_info element.
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*/
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symidx = ELF32_R_SYM(rel.r_info);
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/* Read the symbol table entry into memory */
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ret = elf_readsym(loadinfo, symidx, &sym);
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if (ret < 0)
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{
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bdbg("Section %d reloc %d: Failed to read symbol[%d]: %d\n",
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relidx, i, symidx, ret);
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return ret;
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}
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/* Get the value of the symbol (in sym.st_value) */
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ret = elf_symvalue(loadinfo, &sym, exports, nexports);
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if (ret < 0)
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{
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bdbg("Section %d reloc %d: Failed to get value of symbol[%d]: %d\n",
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relidx, i, symidx, ret);
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return ret;
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}
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/* Calculate the relocation address */
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if (rel.r_offset < 0 || rel.r_offset > dstsec->sh_size - sizeof(uint32_t))
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{
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bdbg("Section %d reloc %d: Relocation address out of range, offset %d size %d\n",
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relidx, i, rel.r_offset, dstsec->sh_size);
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return -EINVAL;
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}
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addr = dstsec->sh_addr + rel.r_offset;
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/* Now perform the architecture-specific relocation */
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ret = arch_relocate(&rel, &sym, addr);
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if (ret < 0)
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{
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bdbg("Section %d reloc %d: Relocation failed: %d\n", ret);
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return ret;
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}
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}
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return OK;
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}
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static int elf_relocateadd(FAR struct elf_loadinfo_s *loadinfo, int relidx,
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FAR const struct symtab_s *exports, int nexports)
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{
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bdbg("Not implemented\n");
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return -ENOSYS;
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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_bind
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*
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* Description:
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* Bind the imported symbol names in the loaded module described by
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* 'loadinfo' using the exported symbol values provided by 'symtab'.
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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_bind(FAR struct elf_loadinfo_s *loadinfo,
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FAR const struct symtab_s *exports, int nexports)
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{
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int ret;
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int i;
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/* Find the symbol and string tables */
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ret = elf_findsymtab(loadinfo);
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if (ret < 0)
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{
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return ret;
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}
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/* Allocate an I/O buffer. This buffer is used by elf_symname() to
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* accumulate the variable length symbol name.
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*/
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ret = elf_allocbuffer(loadinfo);
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if (ret < 0)
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{
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bdbg("elf_allocbuffer failed: %d\n", ret);
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return -ENOMEM;
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}
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/* Process relocations in every allocated section */
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for (i = 1; i < loadinfo->ehdr.e_shnum; i++)
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{
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/* Get the index to the relocation section */
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int infosec = loadinfo->shdr[i].sh_info;
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if (infosec >= loadinfo->ehdr.e_shnum)
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{
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continue;
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}
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/* Make sure that the section is allocated. We can't relocated
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* sections that were not loaded into memory.
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*/
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if ((loadinfo->shdr[infosec].sh_flags & SHF_ALLOC) == 0)
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{
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continue;
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}
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/* Process the relocations by type */
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if (loadinfo->shdr[i].sh_type == SHT_REL)
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{
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ret = elf_relocate(loadinfo, i, exports, nexports);
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}
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else if (loadinfo->shdr[i].sh_type == SHT_RELA)
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{
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ret = elf_relocateadd(loadinfo, i, exports, nexports);
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}
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if (ret < 0)
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{
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break;
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}
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}
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/* Flush the instruction cache before starting the newly loaded module */
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#ifdef CONFIG_ELF_ICACHE
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arch_flushicache((FAR void*)loadinfo->elfalloc, loadinfo->elfsize);
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#endif
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return ret;
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}
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