#include <assert.h>
#include <stdlib.h>
+#include <string.h>
#include <sys/types.h>
-#include <libelf/gelf.h>
#include <libelfu/libelfu.h>
-typedef enum Destsegment {
- DS_UNKNOWN,
- DS_TEXT,
- DS_DATA,
-} Destsegment;
-
-static Destsegment destsegment(ElfuScn *ms)
+static int appendData(ElfuScn *ms, void *buf, size_t len)
{
- if (!(ms->shdr.sh_flags & SHF_ALLOC)) {
- return DS_UNKNOWN;
- }
+ void *newbuf;
+
+ assert(ms);
+ assert(ms->shdr.sh_type != SHT_NOBITS);
+ assert(ms->data.d_buf);
- if (!(ms->shdr.sh_flags & SHF_WRITE)
- && (ms->shdr.sh_flags & SHF_EXECINSTR)) {
- return DS_TEXT;
- } else if ((ms->shdr.sh_flags & SHF_WRITE)
- && !(ms->shdr.sh_flags & SHF_EXECINSTR)) {
- return DS_DATA;
+ newbuf = realloc(ms->data.d_buf, ms->shdr.sh_size + len);
+ if (!newbuf) {
+ ELFU_WARN("appendData: malloc() failed for newbuf.\n");
+ return 1;
}
- return DS_UNKNOWN;
-}
+ ms->data.d_buf = newbuf;
+ memcpy(newbuf + ms->shdr.sh_size, buf, len);
+ ms->shdr.sh_size += len;
+ ms->data.d_size += len;
+ assert(ms->shdr.sh_size == ms->data.d_size);
+ return 0;
+}
-static ElfuScn* insertSection(ElfuElf *me, ElfuElf *mrel, ElfuScn *ms)
+static ElfuScn* insertSection(ElfuElf *me, ElfuElf *mrel, ElfuScn *oldscn)
{
- ElfuPhdr *mp;
- ElfuPhdr *first = NULL;
- ElfuPhdr *last = NULL;
ElfuScn *newscn = NULL;
- ElfuPhdr *injAnchor;
- int searchForCode = 0;
-
- switch (destsegment(ms)) {
- case DS_TEXT:
- searchForCode = 1;
- case DS_DATA:
- newscn = elfu_mCloneScn(ms);
- if (!newscn) {
- return NULL;
+ GElf_Addr injAddr;
+ GElf_Off injOffset;
+ ElfuPhdr *injPhdr;
+
+ if (oldscn->shdr.sh_flags & SHF_ALLOC) {
+ newscn = elfu_mCloneScn(oldscn);
+ if (!newscn) {
+ return NULL;
+ }
+
+ if (newscn->shdr.sh_type == SHT_NOBITS) {
+ /* Expand this to SHT_PROGBITS, then insert as such. */
+
+ assert(!newscn->data.d_buf);
+
+ newscn->data.d_buf = malloc(newscn->shdr.sh_size);
+ if (!newscn->data.d_buf) {
+ goto ERROR;
}
+ newscn->data.d_size = newscn->shdr.sh_size;
+ newscn->shdr.sh_type = SHT_PROGBITS;
+ }
- /* Find first and last LOAD PHDRs. */
- CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
- if (mp->phdr.p_type != PT_LOAD) {
- continue;
- }
+ 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 (!first || mp->phdr.p_vaddr < first->phdr.p_vaddr) {
- first = mp;
- }
- if (!last || mp->phdr.p_vaddr > last->phdr.p_vaddr) {
- /* No need to check p_memsz as segments may not overlap in memory. */
- last = mp;
+ if (!injPhdr) {
+ ELFU_WARN("insertSection: Could not find a place to insert section.\n");
+ goto ERROR;
+ }
+
+ ELFU_INFO("Inserting %s at address 0x%jx...\n",
+ elfu_mScnName(mrel, oldscn),
+ injAddr);
+
+ injOffset = injAddr - injPhdr->phdr.p_vaddr + injPhdr->phdr.p_offset;
+
+ newscn->shdr.sh_addr = injAddr;
+ newscn->shdr.sh_offset = injOffset;
+
+ if (CIRCLEQ_EMPTY(&injPhdr->childScnList)
+ || CIRCLEQ_LAST(&injPhdr->childScnList)->shdr.sh_offset < injOffset) {
+ CIRCLEQ_INSERT_TAIL(&injPhdr->childScnList, newscn, elemChildScn);
+ } else {
+ ElfuScn *ms;
+ CIRCLEQ_FOREACH(ms, &injPhdr->childScnList, elemChildScn) {
+ if (injOffset < ms->shdr.sh_offset) {
+ CIRCLEQ_INSERT_BEFORE(&injPhdr->childScnList, ms, newscn, elemChildScn);
+ break;
}
}
+ }
- if (searchForCode) {
- if ((first->phdr.p_flags & PF_X) && !(first->phdr.p_flags & PF_W)) {
- injAnchor = first;
- } else if ((last->phdr.p_flags & PF_X) && !(last->phdr.p_flags & PF_W)) {
- injAnchor = last;
- } else {
- injAnchor = NULL;
- }
- } else {
- if ((first->phdr.p_flags & PF_W) && !(first->phdr.p_flags & PF_X)) {
- injAnchor = first;
- } else if ((last->phdr.p_flags & PF_W) && !(last->phdr.p_flags & PF_X)) {
- injAnchor = last;
- } else {
- injAnchor = NULL;
- }
+
+ /* Inject name */
+ if (me->shstrtab) {
+ char *newname;
+ size_t newnamelen;
+
+ newnamelen = strlen("reladd") + 1;
+ if (elfu_mScnName(mrel, oldscn)) {
+ newnamelen += strlen(elfu_mScnName(mrel, oldscn));
}
- if (!injAnchor) {
- ELFU_WARN("insertSection: Could not find injection anchor.\n"
- " It has to be the first or last segment in the memory image.\n");
+ newname = malloc(newnamelen);
+ strcpy(newname, "reladd");
+ strcat(newname, elfu_mScnName(mrel, oldscn));
+
+ if (!newname) {
+ ELFU_WARN("insertSection: malloc() failed for newname. Leaving section name empty.\n");
+ newscn->shdr.sh_name = 0;
} else {
- GElf_Off injOffset;
-
- /* If the anchor is first or last, insert before or after */
- if (injAnchor == first) {
- /* Find first section and inject before it */
- ElfuScn *firstScn = elfu_mScnFirstInSegment(me, injAnchor);
- if (!firstScn) {
- ELFU_WARN("insertSection: mScnFirstInSegment failed.\n");
-
- // TODO: Error handling
- } else {
- injOffset = firstScn->shdr.sh_offset;
-
- /* Make space */
- elfu_mInsertSpaceBefore(me, injOffset, ms->shdr.sh_size);
-
- /* Update memory offset */
- newscn->shdr.sh_addr = injAnchor->phdr.p_vaddr;
-
- /* Insert into chain of sections */
- elfu_mInsertScnInChainBefore(me, firstScn, newscn);
- }
- } else {
- /* Find last section and inject after it */
- ElfuScn *lastScn = elfu_mScnLastInSegment(me, injAnchor);
- if (!lastScn) {
- ELFU_WARN("insertSection: mScnLastInSegment failed.\n");
-
- // TODO: Error handling
- } else {
- injOffset = lastScn->shdr.sh_offset + elfu_gScnSizeFile(&lastScn->shdr);
-
- /* Expand NOBITS sections at injection site, if any. */
- elfu_mExpandNobits(me, injOffset);
-
- /* Recalculate injOffset in case we expanded a NOBITS section */
- lastScn = elfu_mScnLastInSegment(me, injAnchor);
- injOffset = lastScn->shdr.sh_offset + elfu_gScnSizeFile(&lastScn->shdr);
-
- /* Make space */
- elfu_mInsertSpaceAfter(me, injOffset, ms->shdr.sh_size);
-
- /* Update memory offset */
- newscn->shdr.sh_addr = injAnchor->phdr.p_vaddr + (injOffset - injAnchor->phdr.p_offset);
-
- /* Insert into chain of sections */
- elfu_mInsertScnInChainAfter(me, lastScn, newscn);
- }
+ size_t offset = me->shstrtab->shdr.sh_size;
+
+ if (!appendData(me->shstrtab, newname, newnamelen)) {
+ newscn->shdr.sh_name = offset;
}
- /* Update file offset in new section BEFORE we do anything else */
- newscn->shdr.sh_offset = injOffset;
+ free(newname);
+ }
+ }
- /* Inject name */
- // TODO
- newscn->shdr.sh_name = 0;
+ return newscn;
+ } else {
+ ELFU_WARN("insertSection: Skipping non-memory section %s (type %d flags %jd).\n",
+ elfu_mScnName(mrel, oldscn),
+ oldscn->shdr.sh_type,
+ oldscn->shdr.sh_flags);
+ goto ERROR;
+ }
- // TODO: Relocate
+ ERROR:
+ if (newscn) {
+ // TODO: Destroy newscn
+ }
+ return NULL;
+}
- return newscn;
+
+static void* subScnAdd1(ElfuElf *mrel, ElfuScn *ms, void *aux1, void *aux2)
+{
+ (void)aux2;
+ ElfuElf *me = (ElfuElf*)aux1;
+
+ ElfuScn *newscn;
+
+ 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;
+ }
- case DS_UNKNOWN:
- ELFU_WARN("insertSection: Don't know where to insert ' %s with flags %jd (type %d).\n",
- elfu_mScnName(mrel, ms),
- ms->shdr.sh_flags,
- ms->shdr.sh_type);
+ return NULL;
+}
+
+
+static void* subScnAdd2(ElfuElf *mrel, ElfuScn *ms, void *aux1, void *aux2)
+{
+ (void)aux2;
+ ElfuElf *me = (ElfuElf*)aux1;
+ (void)me;
+
+ switch(ms->shdr.sh_type) {
+ case SHT_NULL: /* 0 */
+ case SHT_PROGBITS: /* 1 */
+ case SHT_NOBITS: /* 8 */
+ break;
+
+
+ case SHT_REL: /* 9 */
+ /* Relocate. */
+ elfu_mRelocate32(me, elfu_mScnByOldscn(me, ms->infoptr), ms);
+ break;
+
+ case SHT_RELA: /* 4 */
+ // TODO: Needs a parser
+ //elfu_mRelocate(elfu_mScnByOldscn(me, ms->infoptr), ms);
+
+ case SHT_SYMTAB: /* 2 */
+ /* Merge with the existing table. Take care of string tables also. */
+
+ case SHT_STRTAB: /* 3 */
+ /* May have to be merged with the existing string table for
+ * the symbol table. */
+
+ /* 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("insertSection: Skipping section %s with flags %jd (type %d).\n",
+ ELFU_WARN("mReladd: Skipping section %s (type %d).\n",
elfu_mScnName(mrel, ms),
- ms->shdr.sh_flags,
ms->shdr.sh_type);
- return NULL;
}
- if (newscn) {
- // TODO: Destroy newscn
- }
return NULL;
}
-
void elfu_mReladd(ElfuElf *me, ElfuElf *mrel)
{
- ElfuScn *ms;
-
assert(me);
assert(mrel);
-
/* For each section in object file, guess how to insert it */
- CIRCLEQ_FOREACH(ms, &mrel->scnList, elem) {
- ElfuScn *newscn;
-
- switch(ms->shdr.sh_type) {
- case SHT_NULL: /* 0 */
- continue;
-
- case SHT_PROGBITS: /* 1 */
- /* 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;
+ elfu_mScnForall(mrel, subScnAdd1, me, NULL);
- case SHT_SYMTAB: /* 2 */
- case SHT_DYNSYM: /* 11 */
- /* Merge with the existing table. Take care of string tables also. */
-
- case SHT_STRTAB: /* 3 */
- /* May have to be merged with the existing string table for
- * the symbol table. */
-
- case SHT_RELA: /* 4 */
- case SHT_REL: /* 9 */
- /* Possibly append this in memory to the section model
- * that it describes. */
-
- case SHT_NOBITS: /* 8 */
- /* Expand this to SHT_PROGBITS, then insert as such. */
-
- case SHT_HASH: /* 5 */
- case SHT_DYNAMIC: /* 6 */
- case SHT_SHLIB: /* 10 */
- case SHT_SYMTAB_SHNDX: /* 18 */
-
- /* Don't care about the next ones yet. I've never seen
- * them and they can be implemented when necessary. */
- case SHT_NOTE: /* 7 */
- case SHT_INIT_ARRAY: /* 14 */
- case SHT_FINI_ARRAY: /* 15 */
- case SHT_PREINIT_ARRAY: /* 16 */
- case SHT_GROUP: /* 17 */
- case SHT_NUM: /* 19 */
- default:
- ELFU_WARN("mReladd: Skipping section %s (type %d).\n",
- elfu_mScnName(mrel, ms),
- ms->shdr.sh_type);
- }
- }
+ /* Do relocations and other stuff */
+ elfu_mScnForall(mrel, subScnAdd2, me, NULL);
+
+ /* Re-layout to accommodate new contents */
+ elfu_mLayoutAuto(me);
}
projects / centaur.git / blobdiff