5 #include <libelfu/libelfu.h>
8 static void parseSymtab(ElfuElf *me, ElfuScn *ms, ElfuScn**origScnArr)
17 /* Parse symbols from their elfclass-specific format */
18 if (me->elfclass == ELFCLASS32) {
19 for (i = 1; (i + 1) * sizeof(Elf32_Sym) <= ms->shdr.sh_size; i++) {
20 Elf32_Sym *cursym = ((Elf32_Sym*)ms->databuf) + i;
21 ElfuSym *newsym = malloc(sizeof(*sym));
24 newsym->name = cursym->st_name;
25 newsym->value = cursym->st_value;
26 newsym->size = cursym->st_size;
27 newsym->bind = ELF32_ST_BIND(cursym->st_info);
28 newsym->type = ELF32_ST_TYPE(cursym->st_info);
29 newsym->other = cursym->st_other;
30 newsym->shndx = cursym->st_shndx;
32 CIRCLEQ_INSERT_TAIL(&ms->symtab.syms, newsym, elem);
34 } else if (me->elfclass == ELFCLASS64) {
35 for (i = 1; (i + 1) * sizeof(Elf64_Sym) <= ms->shdr.sh_size; i++) {
36 Elf64_Sym *cursym = ((Elf64_Sym*)ms->databuf) + i;
37 ElfuSym *newsym = malloc(sizeof(*sym));
40 newsym->name = cursym->st_name;
41 newsym->value = cursym->st_value;
42 newsym->size = cursym->st_size;
43 newsym->bind = ELF64_ST_BIND(cursym->st_info);
44 newsym->type = ELF64_ST_TYPE(cursym->st_info);
45 newsym->other = cursym->st_other;
46 newsym->shndx = cursym->st_shndx;
48 CIRCLEQ_INSERT_TAIL(&ms->symtab.syms, newsym, elem);
51 /* Unknown elfclass */
55 /* For each section, find the section it points to if any. */
56 CIRCLEQ_FOREACH(sym, &ms->symtab.syms, elem) {
64 sym->scnptr = origScnArr[sym->shndx - 1];
71 static void parseReltab32(ElfuScn *ms)
79 for (i = 0; (i + 1) * sizeof(Elf32_Rel) <= ms->shdr.sh_size; i++) {
80 Elf32_Rel *currel = &(((Elf32_Rel*)ms->databuf)[i]);
83 rel = malloc(sizeof(*rel));
86 rel->offset = currel->r_offset;
87 rel->sym = ELF32_R_SYM(currel->r_info);
88 rel->type = ELF32_R_TYPE(currel->r_info);
92 CIRCLEQ_INSERT_TAIL(&ms->reltab.rels, rel, elem);
97 static void parseRelatab64(ElfuScn *ms)
105 for (i = 0; (i + 1) * sizeof(Elf64_Rela) <= ms->shdr.sh_size; i++) {
106 Elf64_Rela *currel = &(((Elf64_Rela*)ms->databuf)[i]);
109 rel = malloc(sizeof(*rel));
112 rel->offset = currel->r_offset;
113 rel->sym = ELF64_R_SYM(currel->r_info);
114 rel->type = ELF64_R_TYPE(currel->r_info);
116 rel->addend = currel->r_addend;
118 CIRCLEQ_INSERT_TAIL(&ms->reltab.rels, rel, elem);
123 static int cmpScnOffs(const void *ms1, const void *ms2)
125 ElfuScn *s1 = *(ElfuScn**)ms1;
126 ElfuScn *s2 = *(ElfuScn**)ms2;
131 s1 = *(ElfuScn**)ms1;
132 s2 = *(ElfuScn**)ms2;
138 if (s1->shdr.sh_offset < s2->shdr.sh_offset) {
140 } else if (s1->shdr.sh_offset == s2->shdr.sh_offset) {
142 } else /* if (s1->shdr.sh_offset > s2->shdr.sh_offset) */ {
149 static ElfuPhdr* parentPhdr(ElfuElf *me, ElfuScn *ms)
156 CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
157 if (mp->phdr.p_type != PT_LOAD) {
161 if (PHDR_CONTAINS_SCN_IN_MEMORY(&mp->phdr, &ms->shdr)) {
165 /* Give sections a second chance if they do not have any sh_addr
167 /* Actually we don't, because it's ambiguous.
168 * Re-enable for experiments with strangely-formatted files.
169 if (ms->shdr.sh_addr == 0
170 && PHDR_CONTAINS_SCN_IN_FILE(&mp->phdr, &ms->shdr)
171 && OFFS_END(ms->shdr.sh_offset, ms->shdr.sh_size)
172 <= OFFS_END(mp->phdr.p_offset, mp->phdr.p_memsz)) {
182 static ElfuPhdr* modelFromPhdr(GElf_Phdr *phdr)
188 mp = elfu_mPhdrAlloc();
199 static ElfuScn* modelFromSection(Elf_Scn *scn)
205 ms = elfu_mScnAlloc();
211 assert(gelf_getshdr(scn, &ms->shdr) == &ms->shdr);
213 /* Copy each data part in source segment */
214 if (SCNFILESIZE(&ms->shdr) > 0) {
217 ms->databuf = malloc(ms->shdr.sh_size);
219 ELFU_WARN("modelFromSection: malloc() failed for data buffer (%x bytes).\n", (unsigned)ms->shdr.sh_size);
223 /* A non-empty section should contain at least one data block. */
224 data = elf_rawdata(scn, NULL);
227 /* elf_rawdata() always returns ELF_T_BYTE */
228 assert(data->d_type == ELF_T_BYTE);
231 if (data->d_off + data->d_size > ms->shdr.sh_size) {
232 ELFU_WARN("modelFromSection: libelf delivered a bogus data blob. Skipping\n");
234 memcpy((char*)ms->databuf + data->d_off, data->d_buf, data->d_size);
237 data = elf_rawdata(scn, data);
253 ElfuElf* elfu_mFromElf(Elf *e)
257 size_t i, numPhdr, numShdr;
258 ElfuScn **secArray = NULL;
261 if (elfu_eCheck(e)) {
265 me = malloc(sizeof(ElfuElf));
267 ELFU_WARN("elfu_mFromElf: malloc() failed for ElfuElf.\n");
273 CIRCLEQ_INIT(&me->phdrList);
274 CIRCLEQ_INIT(&me->orphanScnList);
278 me->elfclass = gelf_getclass(e);
279 assert(me->elfclass != ELFCLASSNONE);
280 assert(gelf_getehdr(e, &me->ehdr) == &me->ehdr);
283 /* Get the section string table index */
284 if (elf_getshdrstrndx(e, &shstrndx) != 0) {
290 assert(!elf_getphdrnum(e, &numPhdr));
291 for (i = 0; i < numPhdr; i++) {
295 assert(gelf_getphdr(e, i, &phdr) == &phdr);
297 mp = modelFromPhdr(&phdr);
302 CIRCLEQ_INSERT_TAIL(&me->phdrList, mp, elem);
308 /* Find PHDR -> PHDR dependencies (needs sorted sections) */
309 CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
312 if (mp->phdr.p_type != PT_LOAD) {
316 CIRCLEQ_FOREACH(mp2, &me->phdrList, elem) {
321 if (mp->phdr.p_vaddr <= mp2->phdr.p_vaddr
322 && OFFS_END(mp2->phdr.p_vaddr, mp2->phdr.p_memsz) <= OFFS_END(mp->phdr.p_vaddr, mp->phdr.p_memsz)) {
323 CIRCLEQ_INSERT_TAIL(&mp->childPhdrList, mp2, elemChildPhdr);
331 assert(!elf_getshdrnum(e, &numShdr));
333 secArray = malloc((numShdr - 1) * sizeof(*secArray));
335 ELFU_WARN("elfu_mFromElf: malloc() failed for secArray.\n");
339 for (i = 1; i < numShdr; i++) {
343 scn = elf_getscn(e, i);
346 ms = modelFromSection(scn);
359 /* Find sh_link and sh_info dependencies (needs sections in original order) */
360 for (i = 0; i < numShdr - 1; i++) {
361 ElfuScn *ms = secArray[i];
363 switch (ms->shdr.sh_type) {
366 if (ms->shdr.sh_info > 0) {
367 ms->infoptr = secArray[ms->shdr.sh_info - 1];
375 case SHT_GNU_verneed:
376 if (ms->shdr.sh_link > 0) {
377 ms->linkptr = secArray[ms->shdr.sh_link - 1];
383 /* Parse symtabs (needs sections in original order) */
384 for (i = 0; i < numShdr - 1; i++) {
385 ElfuScn *ms = secArray[i];
387 switch (ms->shdr.sh_type) {
391 parseSymtab(me, ms, secArray);
397 /* Parse relocations */
398 for (i = 0; i < numShdr - 1; i++) {
399 ElfuScn *ms = secArray[i];
401 switch (ms->shdr.sh_type) {
403 if (me->elfclass == ELFCLASS32) {
405 } else if (me->elfclass == ELFCLASS64) {
406 /* Not used on x86-64 */
411 if (me->elfclass == ELFCLASS32) {
412 /* Not used on x86-32 */
414 } else if (me->elfclass == ELFCLASS64) {
422 /* Sort sections by file offset */
423 qsort(secArray, numShdr - 1, sizeof(*secArray), cmpScnOffs);
426 /* Find PHDR -> Section dependencies (needs sorted sections) */
427 for (i = 0; i < numShdr - 1; i++) {
428 ElfuScn *ms = secArray[i];
430 ElfuPhdr *parent = parentPhdr(me, ms);
433 GElf_Off shaddr = parent->phdr.p_vaddr +
434 (ms->shdr.sh_offset - parent->phdr.p_offset);
436 if (ms->shdr.sh_addr == 0) {
437 ms->shdr.sh_addr = shaddr;
439 assert(ms->shdr.sh_addr == shaddr);
442 CIRCLEQ_INSERT_TAIL(&parent->childScnList, ms, elemChildScn);
444 CIRCLEQ_INSERT_TAIL(&me->orphanScnList, ms, elemChildScn);
458 // TODO: Free data structures
461 ELFU_WARN("elfu_mFromElf: Failed to load file.\n");