/* This file is part of centaur.
*
* centaur is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License 2 as
* published by the Free Software Foundation.
* centaur is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with centaur. If not, see .
*/
#include
#include
#include
#include
#include
static ElfuScn* cloneScn(ElfuScn *ms)
{
ElfuScn *newscn;
assert(ms);
newscn = elfu_mScnAlloc();
if (!newscn) {
return NULL;
}
newscn->shdr = ms->shdr;
if (ms->databuf) {
void *newbuf = malloc(ms->shdr.sh_size);
if (!newbuf) {
ELFU_WARN("cloneScn: Could not allocate memory for new data buffer.\n");
free(newscn);
return NULL;
}
memcpy(newbuf, ms->databuf, ms->shdr.sh_size);
newscn->databuf = newbuf;
}
newscn->oldptr = ms;
return newscn;
}
static ElfuScn* insertSection(ElfuElf *me, ElfuElf *mrel, ElfuScn *oldscn)
{
ElfuScn *newscn = NULL;
GElf_Addr injAddr;
GElf_Off injOffset;
ElfuPhdr *injPhdr;
if (!(oldscn->shdr.sh_flags & SHF_ALLOC)) {
ELFU_WARN("insertSection: Skipping non-memory section %s (type %d flags %u).\n",
elfu_mScnName(mrel, oldscn),
oldscn->shdr.sh_type,
(unsigned)oldscn->shdr.sh_flags);
goto ERROR;
} else {
newscn = cloneScn(oldscn);
if (!newscn) {
return NULL;
}
if (newscn->shdr.sh_type == SHT_NOBITS) {
/* Expand this to SHT_PROGBITS, then insert as such. */
assert(!newscn->databuf);
newscn->databuf = malloc(newscn->shdr.sh_size);
if (!newscn->databuf) {
goto ERROR;
}
newscn->shdr.sh_type = SHT_PROGBITS;
}
injAddr = elfu_mLayoutGetSpaceInPhdr(me,
newscn->shdr.sh_size,
newscn->shdr.sh_addralign,
newscn->shdr.sh_flags & SHF_WRITE,
newscn->shdr.sh_flags & SHF_EXECINSTR,
&injPhdr);
if (!injPhdr) {
ELFU_WARN("insertSection: Could not find a place to insert section.\n");
goto ERROR;
}
ELFU_INFO("Inserting %s at address 0x%x...\n",
elfu_mScnName(mrel, oldscn),
(unsigned)injAddr);
injOffset = injAddr - injPhdr->phdr.p_vaddr + injPhdr->phdr.p_offset;
newscn->shdr.sh_addr = injAddr;
newscn->shdr.sh_offset = injOffset;
/* Insert section in child list, ordered by memory address */
if (CIRCLEQ_EMPTY(&injPhdr->childScnList)
|| CIRCLEQ_LAST(&injPhdr->childScnList)->shdr.sh_addr < injAddr) {
CIRCLEQ_INSERT_TAIL(&injPhdr->childScnList, newscn, elemChildScn);
} else {
ElfuScn *ms;
CIRCLEQ_FOREACH(ms, &injPhdr->childScnList, elemChildScn) {
if (injAddr < ms->shdr.sh_addr) {
CIRCLEQ_INSERT_BEFORE(&injPhdr->childScnList, ms, newscn, elemChildScn);
break;
}
}
}
/* Inject name */
if (me->shstrtab) {
size_t newnamelen;
newnamelen = strlen("reladd") + 1;
if (elfu_mScnName(mrel, oldscn)) {
newnamelen += strlen(elfu_mScnName(mrel, oldscn));
}
char newname[newnamelen];
strcpy(newname, "reladd");
strcat(newname, elfu_mScnName(mrel, oldscn));
newscn->shdr.sh_name = me->shstrtab->shdr.sh_size;
if (elfu_mScnAppendData(me->shstrtab, newname, newnamelen)) {
newscn->shdr.sh_name = 0;
}
}
return newscn;
}
ERROR:
if (newscn) {
elfu_mScnDestroy(newscn);
}
return NULL;
}
static void* subScnAdd1(ElfuElf *mrel, ElfuScn *ms, void *aux1, void *aux2)
{
ElfuScn *newscn;
ElfuElf *me = (ElfuElf*)aux1;
(void)aux2;
switch(ms->shdr.sh_type) {
case SHT_PROGBITS: /* 1 */
case SHT_NOBITS: /* 8 */
/* Ignore empty sections */
if (ms->shdr.sh_size == 0) {
break;
}
/* Find a place where it belongs and shove it in. */
newscn = insertSection(me, mrel, ms);
if (!newscn) {
ELFU_WARN("mReladd: Could not insert section %s (type %d), skipping.\n",
elfu_mScnName(mrel, ms),
ms->shdr.sh_type);
}
break;
}
return NULL;
}
static void* subScnAdd2(ElfuElf *mrel, ElfuScn *ms, void *aux1, void *aux2)
{
ElfuElf *me = (ElfuElf*)aux1;
(void)aux2;
switch(ms->shdr.sh_type) {
case SHT_NULL: /* 0 */
case SHT_PROGBITS: /* 1 */
case SHT_SYMTAB: /* 2 */
case SHT_STRTAB: /* 3 */
case SHT_NOBITS: /* 8 */
break;
case SHT_RELA: /* 4 */
case SHT_REL: /* 9 */
/* Relocate. */
if (elfu_mRelocate(me, elfu_mScnByOldscn(me, ms->infoptr), ms)) {
return (void*)-1;
}
break;
/* The next section types either do not occur in .o files, or are
* not strictly necessary to process here. */
case SHT_NOTE: /* 7 */
case SHT_HASH: /* 5 */
case SHT_DYNAMIC: /* 6 */
case SHT_SHLIB: /* 10 */
case SHT_DYNSYM: /* 11 */
case SHT_INIT_ARRAY: /* 14 */
case SHT_FINI_ARRAY: /* 15 */
case SHT_PREINIT_ARRAY: /* 16 */
case SHT_GROUP: /* 17 */
case SHT_SYMTAB_SHNDX: /* 18 */
case SHT_NUM: /* 19 */
default:
ELFU_WARN("mReladd: Skipping section %s (type %d).\n",
elfu_mScnName(mrel, ms),
ms->shdr.sh_type);
}
return NULL;
}
static void insertSymClone(ElfuElf *me, const ElfuScn *oldmsst, const ElfuSym *oldsym)
{
GElf_Xword newsize;
char *newbuf;
ElfuScn *newscn = NULL;
ElfuSym *newsym;
char *oldsymname;
assert(me);
assert(oldmsst);
assert(oldsym);
/* If the old symbol pointed to a section, find its clone in the target */
if (oldsym->scnptr) {
newscn = elfu_mScnByOldscn(me, oldsym->scnptr);
/* If we didn't copy the section referenced, we won't
* copy this symbol either */
if (!newscn) {
return;
}
}
/* If we don't have a symbol table, create one so we have somewhere to
* write our new symbols to. */
elfu_mSymtabAddGlobalDymtabIfNotPresent(me);
/* Allocate memory for the cloned symbol */
newsym = malloc(sizeof(*newsym));
if (!newsym) {
ELFU_WARN("insertSymClone: malloc() failed for newsym.\n");
goto ERROR;
}
oldsymname = ELFU_SYMSTR(oldmsst, oldsym->name);
/* Expand .strtab, append symbol name, link newsym to it */
newsize = me->symtab->linkptr->shdr.sh_size + strlen(oldsymname) + 1;
newbuf = realloc(me->symtab->linkptr->databuf, newsize);
if (!newbuf) {
ELFU_WARN("insertSymClone: realloc() failed for strtab.\n");
goto ERROR;
}
me->symtab->linkptr->databuf = newbuf;
newsym->name = me->symtab->linkptr->shdr.sh_size;
strcpy(newbuf + newsym->name, oldsymname);
me->symtab->linkptr->shdr.sh_size = newsize;
/* Copy all other fields */
newsym->scnptr = newscn;
newsym->shndx = oldsym->shndx; /* If scnptr == NULL, this becomes relevant */
newsym->bind = oldsym->bind;
newsym->other = oldsym->other;
newsym->size = oldsym->size;
newsym->type = oldsym->type;
newsym->value = oldsym->value;
/* In executables, symbol addresses need to be in memory */
if (newscn) {
newsym->value += newscn->shdr.sh_addr;
}
/* Insert symbol */
CIRCLEQ_INSERT_TAIL(&me->symtab->symtab.syms, newsym, elem);
return;
ERROR:
if (newsym) {
free(newsym);
}
}
static void mergeSymtab(ElfuElf *me, const ElfuElf *mrel)
{
ElfuSym *sym;
assert(me);
assert(mrel);
CIRCLEQ_FOREACH(sym, &mrel->symtab->symtab.syms, elem) {
insertSymClone(me, mrel->symtab, sym);
}
elfu_mSymtabFlatten(me);
}
int elfu_mReladd(ElfuElf *me, const ElfuElf *mrel)
{
assert(me);
assert(mrel);
/* For each section in object file, guess how to insert it */
elfu_mScnForall((ElfuElf*)mrel, subScnAdd1, me, NULL);
mergeSymtab(me, mrel);
/* Do relocations and other stuff */
if (elfu_mScnForall((ElfuElf*)mrel, subScnAdd2, me, NULL)) {
ELFU_WARN("elfu_mReladd: Reladd aborted. Target model is unclean.\n");
return -1;
}
/* Re-layout to accommodate new contents */
elfu_mLayoutAuto(me);
return 0;
}