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-rw-r--r--src/libelfu/modelops/reladd.c323
1 files changed, 323 insertions, 0 deletions
diff --git a/src/libelfu/modelops/reladd.c b/src/libelfu/modelops/reladd.c
new file mode 100644
index 0000000..bc909e4
--- /dev/null
+++ b/src/libelfu/modelops/reladd.c
@@ -0,0 +1,323 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <libelfu/libelfu.h>
+
+
+static int appendData(ElfuScn *ms, void *buf, size_t len)
+{
+ char *newbuf;
+
+ assert(ms);
+ assert(ms->shdr.sh_type != SHT_NOBITS);
+ assert(ms->data.d_buf);
+
+ newbuf = realloc(ms->data.d_buf, ms->shdr.sh_size + len);
+ if (!newbuf) {
+ ELFU_WARN("appendData: malloc() failed for newbuf.\n");
+ return 1;
+ }
+
+ 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 *oldscn)
+{
+ ElfuScn *newscn = 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;
+ }
+
+ 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;
+
+ 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;
+ }
+ }
+ }
+
+
+ /* 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));
+ }
+
+ 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 {
+ size_t offset = me->shstrtab->shdr.sh_size;
+
+ if (!appendData(me->shstrtab, newname, newnamelen)) {
+ newscn->shdr.sh_name = offset;
+ }
+
+ free(newname);
+ }
+ }
+
+ return newscn;
+ } else {
+ 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;
+ }
+
+ ERROR:
+ if (newscn) {
+ // TODO: Destroy 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_STRTAB: /* 3 */
+ case SHT_NOBITS: /* 8 */
+ break;
+
+
+ case SHT_REL: /* 9 */
+ /* Relocate. */
+ elfu_mRelocate(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. */
+
+ /* 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;
+ }
+ }
+
+ // TODO: Allocate symtab if none present
+ assert(me->symtab);
+
+ /* 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->data.d_buf, newsize);
+ if (!newbuf) {
+ ELFU_WARN("insertSymClone: realloc() failed for strtab.\n");
+ goto ERROR;
+ }
+
+ me->symtab->linkptr->data.d_buf = newbuf;
+
+ newsym->name = me->symtab->linkptr->shdr.sh_size;
+
+ strcpy(newbuf + newsym->name, oldsymname);
+
+ me->symtab->linkptr->data.d_size = newsize;
+ 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);
+ }
+}
+
+
+
+void 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 */
+ elfu_mScnForall((ElfuElf*)mrel, subScnAdd2, me, NULL);
+
+ /* Re-layout to accommodate new contents */
+ elfu_mLayoutAuto(me);
+}
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