diff options
Diffstat (limited to 'src/modelops/reladd.c')
| -rw-r--r-- | src/modelops/reladd.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/src/modelops/reladd.c b/src/modelops/reladd.c new file mode 100644 index 0000000..2fdfb48 --- /dev/null +++ b/src/modelops/reladd.c @@ -0,0 +1,229 @@ +#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) +{ + void *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%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; + } + } + } + + + /* 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 %jd).\n", + elfu_mScnName(mrel, oldscn), + oldscn->shdr.sh_type, + 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) +{ + (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; + } + + 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_STRTAB: /* 3 */ + 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. */ + + /* 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; +} + + +void elfu_mReladd(ElfuElf *me, ElfuElf *mrel) +{ + assert(me); + assert(mrel); + + /* For each section in object file, guess how to insert it */ + elfu_mScnForall(mrel, subScnAdd1, me, NULL); + + /* Do relocations and other stuff */ + elfu_mScnForall(mrel, subScnAdd2, me, NULL); + + /* Re-layout to accommodate new contents */ + elfu_mLayoutAuto(me); +} |