diff options
Diffstat (limited to 'nuttx/binfmt/libelf/libelf_bind.c')
| -rw-r--r-- | nuttx/binfmt/libelf/libelf_bind.c | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/nuttx/binfmt/libelf/libelf_bind.c b/nuttx/binfmt/libelf/libelf_bind.c new file mode 100644 index 000000000..ccdb5108e --- /dev/null +++ b/nuttx/binfmt/libelf/libelf_bind.c @@ -0,0 +1,334 @@ +/**************************************************************************** + * binfmt/libelf/libelf_bind.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 <stdint.h> +#include <string.h> +#include <elf32.h> +#include <errno.h> +#include <assert.h> +#include <debug.h> + +#include <nuttx/binfmt/elf.h> +#include <nuttx/binfmt/symtab.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 + +#ifndef CONFIG_ELF_BUFFERSIZE +# define CONFIG_ELF_BUFFERSIZE 128 +#endif + +#ifdef CONFIG_ELF_DUMPBUFFER +# define elf_dumpbuffer(m,b,n) bvdbgdumpbuffer(m,b,n) +#else +# define elf_dumpbuffer(m,b,n) +#endif + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: elf_readrel + * + * Description: + * Read the ELF32_Rel structure into memory. + * + ****************************************************************************/ + +static inline int elf_readrel(FAR struct elf_loadinfo_s *loadinfo, + FAR const Elf32_Shdr *relsec, + int index, FAR Elf32_Rel *rel) +{ + off_t offset; + + /* Verify that the symbol table index lies within symbol table */ + + if (index < 0 || index > (relsec->sh_size / sizeof(Elf32_Rel))) + { + bdbg("Bad relocation symbol index: %d\n", index); + return -EINVAL; + } + + /* Get the file offset to the symbol table entry */ + + offset = relsec->sh_offset + sizeof(Elf32_Rel) * index; + + /* And, finally, read the symbol table entry into memory */ + + return elf_read(loadinfo, (FAR uint8_t*)rel, sizeof(Elf32_Rel), offset); +} + +/**************************************************************************** + * Name: elf_relocate and elf_relocateadd + * + * Description: + * Perform all relocations associated with a section. + * + * Returned Value: + * 0 (OK) is returned on success and a negated errno is returned on + * failure. + * + ****************************************************************************/ + +static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx, + FAR const struct symtab_s *exports, int nexports) + +{ + FAR Elf32_Shdr *relsec = &loadinfo->shdr[relidx]; + FAR Elf32_Shdr *dstsec = &loadinfo->shdr[relsec->sh_info]; + Elf32_Rel rel; + Elf32_Sym sym; + uintptr_t addr; + int symidx; + int ret; + int i; + + /* Examine each relocation in the section. 'relsec' is the section + * containing the relations. 'dstsec' is the section containing the data + * to be relocated. + */ + + for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++) + { + /* Read the relocation entry into memory */ + + ret = elf_readrel(loadinfo, relsec, i, &rel); + if (ret < 0) + { + bdbg("Section %d reloc %d: Failed to read relocation entry: %d\n", + relidx, i, ret); + return ret; + } + + /* Get the symbol table index for the relocation. This is contained + * in a bit-field within the r_info element. + */ + + symidx = ELF32_R_SYM(rel.r_info); + + /* Read the symbol table entry into memory */ + + ret = elf_readsym(loadinfo, symidx, &sym); + if (ret < 0) + { + bdbg("Section %d reloc %d: Failed to read symbol[%d]: %d\n", + relidx, i, symidx, ret); + return ret; + } + + /* Get the value of the symbol (in sym.st_value) */ + + ret = elf_symvalue(loadinfo, &sym, exports, nexports); + if (ret < 0) + { + bdbg("Section %d reloc %d: Failed to get value of symbol[%d]: %d\n", + relidx, i, symidx, ret); + return ret; + } + + /* Calculate the relocation address. */ + + if (rel.r_offset < 0 || rel.r_offset > dstsec->sh_size - sizeof(uint32_t)) + { + bdbg("Section %d reloc %d: Relocation address out of range, offset %d size %d\n", + relidx, i, rel.r_offset, dstsec->sh_size); + return -EINVAL; + } + + addr = dstsec->sh_addr + rel.r_offset; + + /* If CONFIG_ADDRENV=y, then 'addr' lies in a virtual address space that + * may not be in place now. elf_addrenv_select() will temporarily + * instantiate that address space. + */ + +#ifdef CONFIG_ADDRENV + ret = elf_addrenv_select(loadinfo); + if (ret < 0) + { + bdbg("ERROR: elf_addrenv_select() failed: %d\n", ret); + return ret; + } +#endif + + /* Now perform the architecture-specific relocation */ + + ret = arch_relocate(&rel, &sym, addr); + if (ret < 0) + { +#ifdef CONFIG_ADDRENV + (void)elf_addrenv_restore(loadinfo); +#endif + bdbg("ERROR: Section %d reloc %d: Relocation failed: %d\n", ret); + return ret; + } + + /* Restore the original address environment */ + +#ifdef CONFIG_ADDRENV + ret = elf_addrenv_restore(loadinfo); + if (ret < 0) + { + bdbg("ERROR: elf_addrenv_restore() failed: %d\n", ret); + return ret; + } +#endif + } + + return OK; +} + +static int elf_relocateadd(FAR struct elf_loadinfo_s *loadinfo, int relidx, + FAR const struct symtab_s *exports, int nexports) +{ + bdbg("Not implemented\n"); + return -ENOSYS; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: elf_bind + * + * Description: + * Bind the imported symbol names in the loaded module described by + * 'loadinfo' using the exported symbol values provided by 'symtab'. + * + * Returned Value: + * 0 (OK) is returned on success and a negated errno is returned on + * failure. + * + ****************************************************************************/ + +int elf_bind(FAR struct elf_loadinfo_s *loadinfo, + FAR const struct symtab_s *exports, int nexports) +{ + int ret; + int i; + + /* Find the symbol and string tables */ + + ret = elf_findsymtab(loadinfo); + if (ret < 0) + { + return ret; + } + + /* Allocate an I/O buffer. This buffer is used by elf_symname() to + * accumulate the variable length symbol name. + */ + + ret = elf_allocbuffer(loadinfo); + if (ret < 0) + { + bdbg("elf_allocbuffer failed: %d\n", ret); + return -ENOMEM; + } + + /* Process relocations in every allocated section */ + + for (i = 1; i < loadinfo->ehdr.e_shnum; i++) + { + /* Get the index to the relocation section */ + + int infosec = loadinfo->shdr[i].sh_info; + if (infosec >= loadinfo->ehdr.e_shnum) + { + continue; + } + + /* Make sure that the section is allocated. We can't relocated + * sections that were not loaded into memory. + */ + + if ((loadinfo->shdr[infosec].sh_flags & SHF_ALLOC) == 0) + { + continue; + } + + /* Process the relocations by type */ + + if (loadinfo->shdr[i].sh_type == SHT_REL) + { + ret = elf_relocate(loadinfo, i, exports, nexports); + } + else if (loadinfo->shdr[i].sh_type == SHT_RELA) + { + ret = elf_relocateadd(loadinfo, i, exports, nexports); + } + + if (ret < 0) + { + break; + } + } + + /* Flush the instruction cache before starting the newly loaded module */ + +#ifdef CONFIG_ELF_ICACHE + arch_flushicache((FAR void*)loadinfo->elfalloc, loadinfo->elfsize); +#endif + + return ret; +} + |