#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 GElf_Word makeSpaceAtOffset(ElfuElf *me, GElf_Off offset, GElf_Word size)
{
- if (!(ms->shdr.sh_flags & SHF_ALLOC)) {
- return DS_UNKNOWN;
+ ElfuPhdr *mp;
+ ElfuScn *ms;
+ /* Force a minimum alignment, just to be sure. */
+ GElf_Word align = 64;
+
+ /* Find maximum alignment size by which we have to shift.
+ * Assumes alignment sizes are always 2^x. */
+ CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
+ if (mp->phdr.p_offset >= offset) {
+ if (mp->phdr.p_align > align) {
+ align = mp->phdr.p_align;
+ }
+ }
}
- 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;
+ CIRCLEQ_FOREACH(ms, &me->orphanScnList, elemChildScn) {
+ if (ms->shdr.sh_offset >= offset) {
+ if (ms->shdr.sh_addralign > align) {
+ align = ms->shdr.sh_addralign;
+ }
+ }
}
- return DS_UNKNOWN;
+ size = ROUNDUP(size, align);
+
+ /* Shift stuff */
+ CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
+ if (mp->phdr.p_type != PT_LOAD) {
+ continue;
+ }
+
+ if (mp->phdr.p_offset >= offset) {
+ ElfuScn *ms;
+ ElfuPhdr *mpc;
+
+ mp->phdr.p_offset += size;
+ CIRCLEQ_FOREACH(mpc, &mp->childPhdrList, elemChildPhdr) {
+ mpc->phdr.p_offset += size;
+ }
+ CIRCLEQ_FOREACH(ms, &mp->childScnList, elemChildScn) {
+ ms->shdr.sh_offset += size;
+ }
+ }
+ }
+
+ CIRCLEQ_FOREACH(ms, &me->orphanScnList, elemChildScn) {
+ if (ms->shdr.sh_offset >= offset) {
+ ms->shdr.sh_offset += size;
+ }
+ }
+
+ if (me->ehdr.e_phoff >= offset) {
+ me->ehdr.e_phoff += size;
+ }
+
+ if (me->ehdr.e_shoff >= offset) {
+ me->ehdr.e_shoff += size;
+ }
+
+ return size;
}
-static ElfuScn* insertSection(ElfuElf *me, ElfuElf *mrel, ElfuScn *ms)
+/* Finds a suitable PHDR to insert a hole into and expands it
+ * if necessary.
+ * Returns memory address the hole will be mapped to, or 0 if
+ * the operation failed. */
+static GElf_Addr getSpaceInPhdr(ElfuElf *me, GElf_Word size,
+ GElf_Word align, int w, int x,
+ ElfuPhdr **injPhdr)
{
- 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;
- }
+ ElfuPhdr *mp;
- /* Find first and last LOAD PHDRs. */
- CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
- if (mp->phdr.p_type != PT_LOAD) {
- continue;
- }
+ assert(!(w && x));
- 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;
+ /* Find first and last LOAD PHDRs.
+ * Don't compare p_memsz - segments don't overlap in memory. */
+ CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
+ if (mp->phdr.p_type != PT_LOAD) {
+ continue;
+ }
+ if (!first || mp->phdr.p_vaddr < first->phdr.p_vaddr) {
+ first = mp;
+ }
+ if (!last || mp->phdr.p_vaddr > last->phdr.p_vaddr) {
+ last = mp;
+ }
+ }
+
+ if ((w && (last->phdr.p_flags & PF_W))
+ || (x && (last->phdr.p_flags & PF_X))) {
+ /* Need to append. */
+ GElf_Off injOffset = OFFS_END(last->phdr.p_offset, last->phdr.p_filesz);
+ GElf_Word injSpace = 0;
+ GElf_Word nobitsize = last->phdr.p_memsz - last->phdr.p_filesz;
+
+ /* Expand NOBITS if any */
+ if (nobitsize > 0) {
+ GElf_Off endOff = OFFS_END(last->phdr.p_offset, last->phdr.p_filesz);
+ GElf_Off endAddr = OFFS_END(last->phdr.p_vaddr, last->phdr.p_filesz);
+ ElfuScn *ms;
+
+ ELFU_INFO("Expanding NOBITS at address 0x%jx...\n", endAddr);
+
+ CIRCLEQ_FOREACH(ms, &last->childScnList, elemChildScn) {
+ if (ms->shdr.sh_offset == endOff) {
+ assert(ms->shdr.sh_type == SHT_NOBITS);
+ assert(ms->shdr.sh_size == nobitsize);
+ ms->data.d_buf = malloc(ms->shdr.sh_size);
+ memset(ms->data.d_buf, '\0', ms->shdr.sh_size);
+ if (!ms->data.d_buf) {
+ ELFU_WARN("mExpandNobits: Could not allocate %jd bytes for NOBITS expansion. Data may be inconsistent.\n", ms->shdr.sh_size);
+ assert(0);
+ goto ERROR;
+ }
+
+ ms->data.d_align = 1;
+ ms->data.d_off = 0;
+ ms->data.d_type = ELF_T_BYTE;
+ ms->data.d_size = ms->shdr.sh_size;
+ ms->data.d_version = elf_version(EV_NONE);
+
+ ms->shdr.sh_type = SHT_PROGBITS;
+ ms->shdr.sh_addr = endAddr;
}
}
- 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;
- }
+ injSpace += makeSpaceAtOffset(me, endOff, nobitsize);
+ injSpace -= nobitsize;
+ injOffset += nobitsize;
+ last->phdr.p_filesz += nobitsize;
+ assert(last->phdr.p_filesz == last->phdr.p_memsz);
+ }
+
+ /* Calculate how much space we need, taking alignment into account */
+ size += ROUNDUP(injOffset, align) - injOffset;
+
+ /* If there is not enough space left, create even more. */
+ if (injSpace < size) {
+ injSpace += makeSpaceAtOffset(me, injOffset, size - injSpace);
+ }
+ assert(injSpace >= size);
+
+ /* Remap ourselves */
+ last->phdr.p_filesz += size;
+ last->phdr.p_memsz += size;
+
+ injOffset = ROUNDUP(injOffset, align);
+
+ if (injPhdr) {
+ *injPhdr = last;
+ }
+ return last->phdr.p_vaddr + (injOffset - last->phdr.p_offset);
+ } else if ((w && (first->phdr.p_flags & PF_W))
+ || (x && (first->phdr.p_flags & PF_X))) {
+ /* Need to prepend or split up the PHDR. */
+ GElf_Off injOffset = OFFS_END(first->phdr.p_offset, first->phdr.p_filesz);
+ ElfuScn *ms;
+
+ /* Round up size to take PHDR alignment into account.
+ * We assume that this is a multiple of the alignment asked for. */
+ assert(first->phdr.p_align >= align);
+ size = ROUNDUP(size, first->phdr.p_align);
+
+ /* Find first section. We assume there is at least one. */
+ assert(!CIRCLEQ_EMPTY(&first->childScnList));
+ injOffset = CIRCLEQ_FIRST(&first->childScnList)->shdr.sh_offset;
+
+ /* Move our sections */
+ CIRCLEQ_FOREACH(ms, &first->childScnList, elemChildScn) {
+ if (ms->shdr.sh_offset >= injOffset) {
+ ms->shdr.sh_offset += size;
}
+ }
- 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");
+ /* Move our PHDRs */
+ CIRCLEQ_FOREACH(mp, &first->childPhdrList, elemChildPhdr) {
+ if (mp->phdr.p_offset >= injOffset) {
+ mp->phdr.p_offset += size;
} 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");
+ mp->phdr.p_vaddr -= size;
+ mp->phdr.p_paddr -= size;
+ }
+ }
- // TODO: Error handling
- } else {
- injOffset = firstScn->shdr.sh_offset;
+ /* Move other PHDRs and sections */
+ assert(size <= makeSpaceAtOffset(me, injOffset, size));
- ELFU_INFO("Inserting %s at offset 0x%jx...\n",
- elfu_mScnName(mrel, ms),
- injOffset);
+ /* Remap ourselves */
+ first->phdr.p_vaddr -= size;
+ first->phdr.p_paddr -= size;
+ first->phdr.p_filesz += size;
+ first->phdr.p_memsz += size;
- /* Make space */
- elfu_mInsertSpaceBefore(me, injOffset, ms->shdr.sh_size);
+ injOffset = ROUNDUP(injOffset, align);
- /* Update memory offset */
- newscn->shdr.sh_addr = injAnchor->phdr.p_vaddr;
+ if (injPhdr) {
+ *injPhdr = first;
+ }
+ return first->phdr.p_vaddr + (injOffset - first->phdr.p_offset);
+ }
- /* 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");
+ ERROR:
+ if (injPhdr) {
+ *injPhdr = NULL;
+ }
+ return 0;
+}
- // TODO: Error handling
- } else {
- injOffset = lastScn->shdr.sh_offset + SCNFILESIZE(&lastScn->shdr);
- ELFU_INFO("Expanding at offset 0x%jx...\n",
- injOffset);
- /* 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 + SCNFILESIZE(&lastScn->shdr);
+static ElfuScn* insertSection(ElfuElf *me, ElfuElf *mrel, ElfuScn *oldscn)
+{
+ ElfuScn *newscn = NULL;
+ GElf_Addr injAddr;
+ GElf_Off injOffset;
+ ElfuPhdr *injPhdr;
- ELFU_INFO("Inserting %s at offset 0x%jx...\n",
- elfu_mScnName(mrel, ms),
- injOffset);
+ if (oldscn->shdr.sh_flags & SHF_ALLOC) {
+ newscn = elfu_mCloneScn(oldscn);
+ if (!newscn) {
+ return NULL;
+ }
- /* 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);
+ injAddr = getSpaceInPhdr(me, newscn->shdr.sh_size,
+ newscn->shdr.sh_addralign,
+ newscn->shdr.sh_flags & SHF_WRITE,
+ newscn->shdr.sh_flags & SHF_EXECINSTR,
+ &injPhdr);
- /* Insert into chain of sections */
- elfu_mInsertScnInChainAfter(me, lastScn, newscn);
- }
- }
+ if (!injPhdr) {
+ ELFU_WARN("insertSection: Could not find a place to insert section.\n");
+ goto ERROR;
+ }
- /* Update file offset in new section BEFORE we do anything else */
- newscn->shdr.sh_offset = injOffset;
+ ELFU_INFO("Inserting %s at address 0x%jx...\n",
+ elfu_mScnName(mrel, oldscn),
+ injAddr);
- /* Inject name */
- // TODO
- newscn->shdr.sh_name = 0;
+ injOffset = injAddr - injPhdr->phdr.p_vaddr + injPhdr->phdr.p_offset;
- // TODO: Relocate
+ newscn->shdr.sh_addr = injAddr;
+ newscn->shdr.sh_offset = injOffset;
- return newscn;
+ 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;
+ }
}
- 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);
- default:
+ /* Inject name */
+ // TODO
+ newscn->shdr.sh_name = 0;
+
+ // TODO: Relocate
+
+ return newscn;
+ } else {
ELFU_WARN("insertSection: Skipping section %s with flags %jd (type %d).\n",
- elfu_mScnName(mrel, ms),
- ms->shdr.sh_flags,
- ms->shdr.sh_type);
- return NULL;
+ elfu_mScnName(mrel, oldscn),
+ oldscn->shdr.sh_flags,
+ oldscn->shdr.sh_type);
+ goto ERROR;
}
+ ERROR:
if (newscn) {
// TODO: Destroy newscn
}
}
+int subScnAdd1(ElfuElf *mrel, ElfuScn *ms, void *aux1, void *aux2)
+{
+ (void)aux2;
+ ElfuElf *me = (ElfuElf*)aux1;
-void elfu_mReladd(ElfuElf *me, ElfuElf *mrel)
+ ElfuScn *newscn;
+
+ switch(ms->shdr.sh_type) {
+ 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;
+ }
+
+ return 0;
+}
+
+
+int subScnAdd2(ElfuElf *mrel, ElfuScn *ms, void *aux1, void *aux2)
{
- ElfuScn *ms;
+ (void)aux2;
+ ElfuElf *me = (ElfuElf*)aux1;
+ (void)me;
+
+ switch(ms->shdr.sh_type) {
+ case SHT_NULL: /* 0 */
+ case SHT_PROGBITS: /* 1 */
+ break;
+ 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);
+ }
+
+ return 0;
+}
+
+
+void elfu_mReladd(ElfuElf *me, ElfuElf *mrel)
+{
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;
-
- 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);
- }
- }
+ elfu_mScnForall(mrel, subScnAdd1, me, NULL);
+
+ /* Do relocations and other stuff */
+ elfu_mScnForall(mrel, subScnAdd2, me, NULL);
}
projects / centaur.git / blobdiff