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334 lines
9.9 KiB
334 lines
9.9 KiB
/**************************************************************************** |
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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_readrel |
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* |
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* Description: |
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* Read the ELF32_Rel structure 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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/* If CONFIG_ADDRENV=y, then 'addr' lies in a virtual address space that |
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* may not be in place now. elf_addrenv_select() will temporarily |
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* instantiate that address space. |
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*/ |
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#ifdef CONFIG_ADDRENV |
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ret = elf_addrenv_select(loadinfo); |
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if (ret < 0) |
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{ |
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bdbg("ERROR: elf_addrenv_select() failed: %d\n", ret); |
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return ret; |
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} |
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#endif |
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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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#ifdef CONFIG_ADDRENV |
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(void)elf_addrenv_restore(loadinfo); |
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#endif |
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bdbg("ERROR: Section %d reloc %d: Relocation failed: %d\n", ret); |
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return ret; |
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} |
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/* Restore the original address environment */ |
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#ifdef CONFIG_ADDRENV |
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ret = elf_addrenv_restore(loadinfo); |
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if (ret < 0) |
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{ |
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bdbg("ERROR: elf_addrenv_restore() failed: %d\n", ret); |
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return ret; |
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} |
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#endif |
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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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