/**************************************************************************** * binfmt/libnxflat/libnxflat_bind.c * * Copyright (C) 2009 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include #include /**************************************************************************** * Definitions ****************************************************************************/ /**************************************************************************** * Private Types ****************************************************************************/ /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: nxflat_bindrel32i * * Description: * Perform the NXFLAT_RELOC_TYPE_REL32I binding: * * Meaning: Object file contains a 32-bit offset into I-Space at the the offset. * Fixup: Add mapped I-Space address to the offset. * * Returned Value: * 0 (OK) is returned on success and a negated errno is returned on * failure. * ****************************************************************************/ static inline int nxflat_bindrel32i(FAR struct nxflat_loadinfo_s *loadinfo, uint32 offset) { uint32 *addr; bvdbg("NXFLAT_RELOC_TYPE_REL32I Offset: %08x I-Space: %p\n", offset, loadinfo->ispace); if (offset < loadinfo->dsize) { addr = (uint32*)(offset + loadinfo->dspace->region); bvdbg(" Before: %08x\n", *addr); *addr += (uint32)(loadinfo->ispace); bvdbg(" After: %08x\n", *addr); return OK; } else { bdbg("Offset: %08 does not lie in D-Space size: %08x\n", offset, loadinfo->dsize); return -EINVAL; } } /**************************************************************************** * Name: nxflat_bindrel32d * * Description: * Perform the NXFLAT_RELOC_TYPE_REL32D binding: * * Meaning: Object file contains a 32-bit offset into D-Space at the the offset. * Fixup: Add allocated D-Space address to the offset. * * Returned Value: * 0 (OK) is returned on success and a negated errno is returned on * failure. * ****************************************************************************/ static inline int nxflat_bindrel32d(FAR struct nxflat_loadinfo_s *loadinfo, uint32 offset) { uint32 *addr; bvdbg("NXFLAT_RELOC_TYPE_REL32D Offset: %08x D-Space: %p\n", offset, loadinfo->dspace->region); if (offset < loadinfo->dsize) { addr = (uint32*)(offset + loadinfo->dspace->region); bvdbg(" Before: %08x\n", *addr); *addr += (uint32)(loadinfo->dspace->region); bvdbg(" After: %08x\n", *addr); return OK; } else { bdbg("Offset: %08 does not lie in D-Space size: %08x\n", offset, loadinfo->dsize); return -EINVAL; } } /**************************************************************************** * Name: nxflat_gotrelocs * * Description: * Bind all of the GOT relocations in the loaded module described by * 'loadinfo' * * Returned Value: * 0 (OK) is returned on success and a negated errno is returned on * failure. * ****************************************************************************/ static inline int nxflat_gotrelocs(FAR struct nxflat_loadinfo_s *loadinfo) { FAR struct nxflat_reloc_s *relocs; FAR struct nxflat_reloc_s reloc; FAR struct nxflat_hdr_s *hdr; uint32 offset; uint16 nrelocs; int ret; int result; int i; /* The NXFLAT header is the first thing at the beginning of the ISpace. */ hdr = (FAR struct nxflat_hdr_s*)loadinfo->ispace; /* From this, we can get the offset to the list of relocation entries */ offset = ntohl(hdr->h_relocstart); nrelocs = ntohs(hdr->h_reloccount); /* The value of the relocation list that we get from the header is a * file offset. We will have to convert this to an offset into the * DSpace segment to get the pointer to the beginning of the relocation * list. */ DEBUGASSERT(offset >= loadinfo->isize && offset < (loadinfo->isize + loadinfo->dsize)); relocs = (FAR struct nxflat_reloc_s*)(offset - loadinfo->isize + loadinfo->dspace->region); /* Now, traverse the relocation list of imported symbols and attempt to bind * each GOT relocation (imported symbols will be handled elsewhere). */ ret = OK; /* Assume success */ for (i = 0; i < nrelocs; i++) { /* Handle the relocation by the relocation type */ reloc = *relocs++; result = OK; switch (NXFLAT_RELOC_TYPE(reloc.r_info)) { /* NXFLAT_RELOC_TYPE_REL32I Meaning: Object file contains a 32-bit offset * into I-Space at the the offset. * Fixup: Add mapped I-Space address to the offset. */ case NXFLAT_RELOC_TYPE_REL32I: { result = nxflat_bindrel32i(loadinfo, NXFLAT_RELOC_OFFSET(reloc.r_info)); } break; /* NXFLAT_RELOC_TYPE_REL32D Meaning: Object file contains a 32-bit offset * into D-Space at the the offset. * Fixup: Add allocated D-Space address to the * offset. */ case NXFLAT_RELOC_TYPE_REL32D: { result = nxflat_bindrel32d(loadinfo, NXFLAT_RELOC_OFFSET(reloc.r_info)); } break; /* NXFLAT_RELOC_TYPE_ABS32 Meaning: Offset refers to a struct nxflat_import_s * describing a function pointer to be * imported. * Fixup: Provide the absolute function address * in the struct nxflat_import_s instance. */ case NXFLAT_RELOC_TYPE_ABS32: { /* These will be handled together in nxflat_bindimports */ } break; } /* Check for failures */ if (result < 0 && ret == OK) { ret = result; } } return ret; } /**************************************************************************** * Name: nxflat_bindimports * * 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. * ****************************************************************************/ static inline int nxflat_bindimports(FAR struct nxflat_loadinfo_s *loadinfo, FAR const struct symtab_s *exports, int nexports) { FAR struct nxflat_import_s *imports; FAR struct nxflat_hdr_s *hdr; FAR const struct symtab_s *symbol; char *symname; uint32 offset; uint16 nimports; int i; /* The NXFLAT header is the first thing at the beginning of the ISpace. */ hdr = (FAR struct nxflat_hdr_s*)loadinfo->ispace; /* From this, we can get the offset to the list of symbols imported by * this module and the number of symbols imported by this module. */ offset = ntohl(hdr->h_importsymbols); nimports = ntohs(hdr->h_importcount); /* Verify that this module requires imported symbols */ if (offset != 0 && nimports > 0) { /* It does.. make sure that exported symbols are provided */ DEBUGASSERT(symtab && nexports > 0); /* If non-zero, the value of the imported symbol list that we get * from the header is a file offset. We will have to convert this * to an offset into the DSpace segment to get the pointer to the * beginning of the imported symbol list. */ DEBUGASSERT(offset >= loadinfo->isize && offset < loadinfo->isize + loadinfo->dsize); imports = (struct nxflat_import_s*) (offset - loadinfo->isize + loadinfo->dspace->region); /* Now, traverse the list of imported symbols and attempt to bind * each symbol to the value exported by from the exported symbol * table. */ for (i = 0; i < nimports; i++) { /* Get a pointer to the imported symbol name. The name itself * lies in the TEXT segment. But the reference to the name * lies in DATA segment. Therefore, the name reference should * have been relocated when the module was loaded. */ offset = imports[i].i_funcname; DEBUGASSERT(offset < loadinfo->isize); symname = (char*)(offset + loadinfo->ispace); /* Find the exported symbol value for this this symbol name. */ #ifdef CONFIG_SYMTAB_ORDEREDBYNAME symbol = symtab_findorderedbyname(exports, symname, nexports); #else symbol = symtab_findbyname(exports, symname, nexports); #endif if (!symbol) { bdbg("Exported symbol \"%s\" not found\n", symname); return -ENOENT; } /* And put this into the module's import structure. */ imports[i].i_funcaddress = (uint32)symbol->sym_value; bvdbg("Bound imported function '%s' to address %08x\n", symname, imports[i].function_address); } } return OK; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: nxflat_bind * * Description: * Bind the imported symbol names in the loaded module described by * 'loadinfo' using the exported symbol values provided by 'symtab'. * After binding the module, clear the BSS region (which held the relocation * data) in preparation for execution. * * Returned Value: * 0 (OK) is returned on success and a negated errno is returned on * failure. * ****************************************************************************/ int nxflat_bind(FAR struct nxflat_loadinfo_s *loadinfo, FAR const struct symtab_s *exports, int nexports) { /* First bind all GOT relocations (omitting absolute symbol relocations) */ int ret = nxflat_gotrelocs(loadinfo); if (ret == OK) { /* Then bind the imported symbol, absolute relocations separately. * There is no particular reason to do these separately over than * traversing the import list directly is simpler than traversing * it indirectly through the relocation list. */ ret = nxflat_bindimports(loadinfo, exports, nexports); if (ret == OK) { /* Zero the BSS area, trashing the relocations that lived in space * in the file. */ memset((void*)(loadinfo->dspace->region + loadinfo->datasize), 0, loadinfo->bsssize); } } return ret; }