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- /****************************************************************************
- * libs/libc/modlib/modlib_bind.c
- *
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership. The
- * ASF licenses this file to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance with the
- * License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- *
- ****************************************************************************/
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <stdint.h>
- #include <string.h>
- #include <errno.h>
- #include <assert.h>
- #include <debug.h>
- #include <nuttx/elf.h>
- #include <nuttx/lib/modlib.h>
- #include "libc.h"
- #include "modlib/modlib.h"
- /****************************************************************************
- * Private Types
- ****************************************************************************/
- /* REVISIT: This naming breaks the NuttX coding standard, but is consistent
- * with legacy naming of other ELF types.
- */
- typedef struct
- {
- dq_entry_t entry;
- Elf_Sym sym;
- int idx;
- } Elf_SymCache;
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: modlib_readrels
- *
- * Description:
- * Read the (ELF_Rel structure * buffer count) into memory.
- *
- ****************************************************************************/
- static inline int modlib_readrels(FAR struct mod_loadinfo_s *loadinfo,
- FAR const Elf_Shdr *relsec,
- int index, FAR Elf_Rel *rels,
- int count)
- {
- off_t offset;
- int size;
- /* Verify that the symbol table index lies within symbol table */
- if (index < 0 || index > (relsec->sh_size / sizeof(Elf_Rel)))
- {
- berr("ERROR: Bad relocation symbol index: %d\n", index);
- return -EINVAL;
- }
- /* Get the file offset to the symbol table entry */
- offset = sizeof(Elf_Rel) * index;
- size = sizeof(Elf_Rel) * count;
- if (offset + size > relsec->sh_size)
- {
- size = relsec->sh_size - offset;
- }
- /* And, finally, read the symbol table entry into memory */
- return modlib_read(loadinfo, (FAR uint8_t *)rels, size,
- relsec->sh_offset + offset);
- }
- /****************************************************************************
- * Name: modlib_readrelas
- *
- * Description:
- * Read the (ELF_Rela structure * buffer count) into memory.
- *
- ****************************************************************************/
- static inline int modlib_readrelas(FAR struct mod_loadinfo_s *loadinfo,
- FAR const Elf_Shdr *relsec,
- int index, FAR Elf_Rela *relas,
- int count)
- {
- off_t offset;
- int size;
- /* Verify that the symbol table index lies within symbol table */
- if (index < 0 || index > (relsec->sh_size / sizeof(Elf_Rela)))
- {
- berr("ERROR: Bad relocation symbol index: %d\n", index);
- return -EINVAL;
- }
- /* Get the file offset to the symbol table entry */
- offset = sizeof(Elf_Rela) * index;
- size = sizeof(Elf_Rela) * count;
- if (offset + size > relsec->sh_size)
- {
- size = relsec->sh_size - offset;
- }
- /* And, finally, read the symbol table entry into memory */
- return modlib_read(loadinfo, (FAR uint8_t *)relas, size,
- relsec->sh_offset + offset);
- }
- /****************************************************************************
- * Name: modlib_relocate and modlib_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 modlib_relocate(FAR struct module_s *modp,
- FAR struct mod_loadinfo_s *loadinfo, int relidx)
- {
- FAR Elf_Shdr *relsec = &loadinfo->shdr[relidx];
- FAR Elf_Shdr *dstsec = &loadinfo->shdr[relsec->sh_info];
- FAR Elf_Rel *rels;
- FAR Elf_Rel *rel;
- FAR Elf_SymCache *cache;
- FAR Elf_Sym *sym;
- FAR dq_entry_t *e;
- dq_queue_t q;
- uintptr_t addr;
- int symidx;
- int ret;
- int i;
- int j;
- rels = lib_malloc(CONFIG_MODLIB_RELOCATION_BUFFERCOUNT * sizeof(Elf_Rel));
- if (!rels)
- {
- berr("Failed to allocate memory for elf relocation rels\n");
- return -ENOMEM;
- }
- dq_init(&q);
- /* Examine each relocation in the section. 'relsec' is the section
- * containing the relations. 'dstsec' is the section containing the data
- * to be relocated.
- */
- ret = OK;
- for (i = j = 0; i < relsec->sh_size / sizeof(Elf_Rel); i++)
- {
- /* Read the relocation entry into memory */
- rel = &rels[i % CONFIG_MODLIB_RELOCATION_BUFFERCOUNT];
- if (!(i % CONFIG_MODLIB_RELOCATION_BUFFERCOUNT))
- {
- ret = modlib_readrels(loadinfo, relsec, i, rels,
- CONFIG_MODLIB_RELOCATION_BUFFERCOUNT);
- if (ret < 0)
- {
- berr("ERROR: Section %d reloc %d: "
- "Failed to read relocation entry: %d\n",
- relidx, i, ret);
- break;
- }
- }
- /* Get the symbol table index for the relocation. This is contained
- * in a bit-field within the r_info element.
- */
- symidx = ELF_R_SYM(rel->r_info);
- /* First try the cache */
- sym = NULL;
- for (e = dq_peek(&q); e; e = dq_next(e))
- {
- cache = (FAR Elf_SymCache *)e;
- if (cache->idx == symidx)
- {
- dq_rem(&cache->entry, &q);
- dq_addfirst(&cache->entry, &q);
- sym = &cache->sym;
- break;
- }
- }
- /* If the symbol was not found in the cache, we will need to read the
- * symbol from the file.
- */
- if (sym == NULL)
- {
- if (j < CONFIG_MODLIB_SYMBOL_CACHECOUNT)
- {
- cache = lib_malloc(sizeof(Elf_SymCache));
- if (!cache)
- {
- berr("Failed to allocate memory for elf symbols\n");
- ret = -ENOMEM;
- break;
- }
- j++;
- }
- else
- {
- cache = (FAR Elf_SymCache *)dq_remlast(&q);
- }
- sym = &cache->sym;
- /* Read the symbol table entry into memory */
- ret = modlib_readsym(loadinfo, symidx, sym);
- if (ret < 0)
- {
- berr("ERROR: Section %d reloc %d: "
- "Failed to read symbol[%d]: %d\n",
- relidx, i, symidx, ret);
- lib_free(cache);
- break;
- }
- /* Get the value of the symbol (in sym.st_value) */
- ret = modlib_symvalue(modp, loadinfo, sym);
- if (ret < 0)
- {
- /* The special error -ESRCH is returned only in one condition:
- * The symbol has no name.
- *
- * There are a few relocations for a few architectures that do
- * no depend upon a named symbol. We don't know if that is the
- * case here, but we will use a NULL symbol pointer to indicate
- * that case to up_relocate(). That function can then do what
- * is best.
- */
- if (ret == -ESRCH)
- {
- berr("ERROR: Section %d reloc %d: "
- "Undefined symbol[%d] has no name: %d\n",
- relidx, i, symidx, ret);
- }
- else
- {
- berr("ERROR: Section %d reloc %d: "
- "Failed to get value of symbol[%d]: %d\n",
- relidx, i, symidx, ret);
- lib_free(cache);
- break;
- }
- }
- cache->idx = symidx;
- dq_addfirst(&cache->entry, &q);
- }
- if (sym->st_shndx == SHN_UNDEF && sym->st_name == 0)
- {
- sym = NULL;
- }
- /* Calculate the relocation address. */
- if (rel->r_offset < 0 ||
- rel->r_offset > dstsec->sh_size - sizeof(uint32_t))
- {
- berr("ERROR: Section %d reloc %d: "
- "Relocation address out of range, offset %d size %d\n",
- relidx, i, rel->r_offset, dstsec->sh_size);
- ret = -EINVAL;
- break;
- }
- addr = dstsec->sh_addr + rel->r_offset;
- /* Now perform the architecture-specific relocation */
- ret = up_relocate(rel, sym, addr);
- if (ret < 0)
- {
- berr("ERROR: Section %d reloc %d: Relocation failed: %d\n",
- relidx, i, ret);
- break;
- }
- }
- lib_free(rels);
- while ((e = dq_peek(&q)))
- {
- dq_rem(e, &q);
- lib_free(e);
- }
- return ret;
- }
- static int modlib_relocateadd(FAR struct module_s *modp,
- FAR struct mod_loadinfo_s *loadinfo, int relidx)
- {
- FAR Elf_Shdr *relsec = &loadinfo->shdr[relidx];
- FAR Elf_Shdr *dstsec = &loadinfo->shdr[relsec->sh_info];
- FAR Elf_Rela *relas;
- FAR Elf_Rela *rela;
- FAR Elf_SymCache *cache;
- FAR Elf_Sym *sym;
- FAR dq_entry_t *e;
- dq_queue_t q;
- uintptr_t addr;
- int symidx;
- int ret;
- int i;
- int j;
- relas = lib_malloc(CONFIG_MODLIB_RELOCATION_BUFFERCOUNT *
- sizeof(Elf_Rela));
- if (!relas)
- {
- berr("Failed to allocate memory for elf relocation relas\n");
- return -ENOMEM;
- }
- dq_init(&q);
- /* Examine each relocation in the section. 'relsec' is the section
- * containing the relations. 'dstsec' is the section containing the data
- * to be relocated.
- */
- ret = OK;
- for (i = j = 0; i < relsec->sh_size / sizeof(Elf_Rela); i++)
- {
- /* Read the relocation entry into memory */
- rela = &relas[i % CONFIG_MODLIB_RELOCATION_BUFFERCOUNT];
- if (!(i % CONFIG_MODLIB_RELOCATION_BUFFERCOUNT))
- {
- ret = modlib_readrelas(loadinfo, relsec, i, relas,
- CONFIG_MODLIB_RELOCATION_BUFFERCOUNT);
- if (ret < 0)
- {
- berr("ERROR: Section %d reloc %d: "
- "Failed to read relocation entry: %d\n",
- relidx, i, ret);
- break;
- }
- }
- /* Get the symbol table index for the relocation. This is contained
- * in a bit-field within the r_info element.
- */
- symidx = ELF_R_SYM(rela->r_info);
- /* First try the cache */
- sym = NULL;
- for (e = dq_peek(&q); e; e = dq_next(e))
- {
- cache = (FAR Elf_SymCache *)e;
- if (cache->idx == symidx)
- {
- dq_rem(&cache->entry, &q);
- dq_addfirst(&cache->entry, &q);
- sym = &cache->sym;
- break;
- }
- }
- /* If the symbol was not found in the cache, we will need to read the
- * symbol from the file.
- */
- if (sym == NULL)
- {
- if (j < CONFIG_MODLIB_SYMBOL_CACHECOUNT)
- {
- cache = lib_malloc(sizeof(Elf_SymCache));
- if (!cache)
- {
- berr("Failed to allocate memory for elf symbols\n");
- ret = -ENOMEM;
- break;
- }
- j++;
- }
- else
- {
- cache = (FAR Elf_SymCache *)dq_remlast(&q);
- }
- sym = &cache->sym;
- /* Read the symbol table entry into memory */
- ret = modlib_readsym(loadinfo, symidx, sym);
- if (ret < 0)
- {
- berr("ERROR: Section %d reloc %d: "
- "Failed to read symbol[%d]: %d\n",
- relidx, i, symidx, ret);
- lib_free(cache);
- break;
- }
- /* Get the value of the symbol (in sym.st_value) */
- ret = modlib_symvalue(modp, loadinfo, sym);
- if (ret < 0)
- {
- /* The special error -ESRCH is returned only in one condition:
- * The symbol has no name.
- *
- * There are a few relocations for a few architectures that do
- * no depend upon a named symbol. We don't know if that is the
- * case here, but we will use a NULL symbol pointer to indicate
- * that case to up_relocate(). That function can then do what
- * is best.
- */
- if (ret == -ESRCH)
- {
- berr("ERROR: Section %d reloc %d: "
- "Undefined symbol[%d] has no name: %d\n",
- relidx, i, symidx, ret);
- }
- else
- {
- berr("ERROR: Section %d reloc %d: "
- "Failed to get value of symbol[%d]: %d\n",
- relidx, i, symidx, ret);
- lib_free(cache);
- break;
- }
- }
- cache->idx = symidx;
- dq_addfirst(&cache->entry, &q);
- }
- if (sym->st_shndx == SHN_UNDEF && sym->st_name == 0)
- {
- sym = NULL;
- }
- /* Calculate the relocation address. */
- if (rela->r_offset < 0 ||
- rela->r_offset > dstsec->sh_size - sizeof(uint32_t))
- {
- berr("ERROR: Section %d reloc %d: "
- "Relocation address out of range, offset %d size %d\n",
- relidx, i, rela->r_offset, dstsec->sh_size);
- ret = -EINVAL;
- break;
- }
- addr = dstsec->sh_addr + rela->r_offset;
- /* Now perform the architecture-specific relocation */
- ret = up_relocateadd(rela, sym, addr);
- if (ret < 0)
- {
- berr("ERROR: Section %d reloc %d: Relocation failed: %d\n",
- relidx, i, ret);
- break;
- }
- }
- lib_free(relas);
- while ((e = dq_peek(&q)))
- {
- dq_rem(e, &q);
- lib_free(e);
- }
- return ret;
- }
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: modlib_bind
- *
- * Description:
- * Bind the imported symbol names in the loaded module described by
- * 'loadinfo' using the exported symbol values provided by
- * modlib_setsymtab().
- *
- * Input Parameters:
- * modp - Module state information
- * loadinfo - Load state information
- *
- * Returned Value:
- * 0 (OK) is returned on success and a negated errno is returned on
- * failure.
- *
- ****************************************************************************/
- int modlib_bind(FAR struct module_s *modp,
- FAR struct mod_loadinfo_s *loadinfo)
- {
- int ret;
- int i;
- /* Find the symbol and string tables */
- ret = modlib_findsymtab(loadinfo);
- if (ret < 0)
- {
- return ret;
- }
- /* Allocate an I/O buffer. This buffer is used by mod_symname() to
- * accumulate the variable length symbol name.
- */
- ret = modlib_allocbuffer(loadinfo);
- if (ret < 0)
- {
- berr("ERROR: modlib_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 relocate
- * 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 = modlib_relocate(modp, loadinfo, i);
- }
- else if (loadinfo->shdr[i].sh_type == SHT_RELA)
- {
- ret = modlib_relocateadd(modp, loadinfo, i);
- }
- if (ret < 0)
- {
- break;
- }
- }
- /* Ensure that the I and D caches are coherent before starting the newly
- * loaded module by cleaning the D cache (i.e., flushing the D cache
- * contents to memory and invalidating the I cache).
- */
- up_coherent_dcache(loadinfo->textalloc, loadinfo->textsize);
- up_coherent_dcache(loadinfo->datastart, loadinfo->datasize);
- return ret;
- }
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