5 #include <libelfu/libelfu.h>
8 static void parseSymtab32(ElfuScn *ms, ElfuScn**origScnArr)
13 assert(ms->data.d_buf);
17 for (i = 1; (i + 1) * sizeof(Elf32_Sym) <= ms->shdr.sh_size; i++) {
18 Elf32_Sym *cursym = &(((Elf32_Sym*)ms->data.d_buf)[i]);
19 ElfuSym *sym = malloc(sizeof(*sym));
22 sym->name = cursym->st_name;
23 sym->value = cursym->st_value;
24 sym->size = cursym->st_size;
25 sym->bind = ELF32_ST_BIND(cursym->st_info);
26 sym->type = ELF32_ST_TYPE(cursym->st_info);
27 sym->other = cursym->st_other;
28 sym->shndx = cursym->st_shndx;
30 switch (cursym->st_shndx) {
37 sym->scnptr = origScnArr[cursym->st_shndx - 1];
42 CIRCLEQ_INSERT_TAIL(&ms->symtab.syms, sym, elem);
47 static void parseReltab32(ElfuScn *ms)
52 assert(ms->data.d_buf);
55 for (i = 0; (i + 1) * sizeof(Elf32_Rel) <= ms->shdr.sh_size; i++) {
56 Elf32_Rel *currel = &(((Elf32_Rel*)ms->data.d_buf)[i]);
59 rel = malloc(sizeof(*rel));
62 rel->offset = currel->r_offset;
64 rel->sym = ELF32_R_SYM(currel->r_info);
65 rel->type = ELF32_R_TYPE(currel->r_info);
70 CIRCLEQ_INSERT_TAIL(&ms->reltab.rels, rel, elem);
75 static int cmpScnOffs(const void *ms1, const void *ms2)
80 ElfuScn *s1 = *(ElfuScn**)ms1;
81 ElfuScn *s2 = *(ElfuScn**)ms2;
87 if (s1->shdr.sh_offset < s2->shdr.sh_offset) {
89 } else if (s1->shdr.sh_offset == s2->shdr.sh_offset) {
91 } else /* if (s1->shdr.sh_offset > s2->shdr.sh_offset) */ {
98 static ElfuPhdr* parentPhdr(ElfuElf *me, ElfuScn *ms)
105 CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
106 if (mp->phdr.p_type != PT_LOAD) {
110 if (PHDR_CONTAINS_SCN_IN_MEMORY(&mp->phdr, &ms->shdr)) {
114 /* Give sections a second chance if they do not have any sh_addr
116 /* Actually we don't, because it's ambiguous.
117 * Re-enable for experiments with strangely-formatted files.
118 if (ms->shdr.sh_addr == 0
119 && PHDR_CONTAINS_SCN_IN_FILE(&mp->phdr, &ms->shdr)
120 && OFFS_END(ms->shdr.sh_offset, ms->shdr.sh_size)
121 <= OFFS_END(mp->phdr.p_offset, mp->phdr.p_memsz)) {
131 static ElfuPhdr* modelFromPhdr(GElf_Phdr *phdr)
137 mp = malloc(sizeof(ElfuPhdr));
139 ELFU_WARN("modelFromPhdr: malloc() failed for ElfuPhdr.\n");
145 CIRCLEQ_INIT(&mp->childScnList);
146 CIRCLEQ_INIT(&mp->childPhdrList);
152 static ElfuScn* modelFromSection(Elf_Scn *scn)
158 ms = malloc(sizeof(ElfuScn));
160 ELFU_WARN("modelFromSection: malloc() failed for ElfuScn.\n");
165 assert(gelf_getshdr(scn, &ms->shdr) == &ms->shdr);
168 /* Copy each data part in source segment */
169 ms->data.d_align = 1;
170 ms->data.d_buf = NULL;
172 ms->data.d_type = ELF_T_BYTE;
173 ms->data.d_size = ms->shdr.sh_size;
174 ms->data.d_version = elf_version(EV_NONE);
175 if (ms->shdr.sh_type != SHT_NOBITS
176 && ms->shdr.sh_size > 0) {
179 ms->data.d_buf = malloc(ms->shdr.sh_size);
180 if (!ms->data.d_buf) {
181 ELFU_WARN("modelFromSection: malloc() failed for data buffer (%jx bytes).\n", ms->shdr.sh_size);
185 /* A non-empty section should contain at least one data block. */
186 data = elf_rawdata(scn, NULL);
189 ms->data.d_align = data->d_align;
190 ms->data.d_type = data->d_type;
191 ms->data.d_version = data->d_version;
194 if (data->d_off + data->d_size > ms->shdr.sh_size) {
195 ELFU_WARN("modelFromSection: libelf delivered a bogus data blob. Skipping\n");
197 memcpy(ms->data.d_buf + data->d_off, data->d_buf, data->d_size);
200 data = elf_rawdata(scn, data);
209 CIRCLEQ_INIT(&ms->symtab.syms);
210 CIRCLEQ_INIT(&ms->reltab.rels);
225 ElfuElf* elfu_mFromElf(Elf *e)
229 size_t i, numPhdr, numShdr;
230 ElfuScn **secArray = NULL;
233 if (elfu_eCheck(e)) {
237 me = malloc(sizeof(ElfuElf));
239 ELFU_WARN("elfu_mFromElf: malloc() failed for ElfuElf.\n");
245 CIRCLEQ_INIT(&me->phdrList);
246 CIRCLEQ_INIT(&me->orphanScnList);
250 me->elfclass = gelf_getclass(e);
251 assert(me->elfclass != ELFCLASSNONE);
252 assert(gelf_getehdr(e, &me->ehdr) == &me->ehdr);
255 /* Get the section string table index */
256 if (elf_getshdrstrndx(e, &shstrndx) != 0) {
262 assert(!elf_getphdrnum(e, &numPhdr));
263 for (i = 0; i < numPhdr; i++) {
267 assert(gelf_getphdr(e, i, &phdr) == &phdr);
269 mp = modelFromPhdr(&phdr);
274 CIRCLEQ_INSERT_TAIL(&me->phdrList, mp, elem);
280 /* Find PHDR -> PHDR dependencies (needs sorted sections) */
281 CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
284 if (mp->phdr.p_type != PT_LOAD) {
288 CIRCLEQ_FOREACH(mp2, &me->phdrList, elem) {
293 if (mp->phdr.p_vaddr <= mp2->phdr.p_vaddr
294 && OFFS_END(mp2->phdr.p_vaddr, mp2->phdr.p_memsz) <= OFFS_END(mp->phdr.p_vaddr, mp->phdr.p_memsz)) {
295 CIRCLEQ_INSERT_TAIL(&mp->childPhdrList, mp2, elemChildPhdr);
303 assert(!elf_getshdrnum(e, &numShdr));
305 secArray = malloc((numShdr - 1) * sizeof(*secArray));
307 ELFU_WARN("elfu_mFromElf: malloc() failed for secArray.\n");
311 for (i = 1; i < numShdr; i++) {
315 scn = elf_getscn(e, i);
318 ms = modelFromSection(scn);
331 /* Find sh_link and sh_info dependencies (needs sections in original order) */
332 for (i = 0; i < numShdr - 1; i++) {
333 ElfuScn *ms = secArray[i];
335 switch (ms->shdr.sh_type) {
338 if (ms->shdr.sh_info > 0) {
339 ms->infoptr = secArray[ms->shdr.sh_info - 1];
347 case SHT_GNU_verneed:
348 if (ms->shdr.sh_link > 0) {
349 ms->linkptr = secArray[ms->shdr.sh_link - 1];
355 /* Parse symtabs (needs sections in original order) */
356 for (i = 0; i < numShdr - 1; i++) {
357 ElfuScn *ms = secArray[i];
359 switch (ms->shdr.sh_type) {
363 if (me->elfclass == ELFCLASS32) {
364 parseSymtab32(ms, secArray);
365 } else if (me->elfclass == ELFCLASS64) {
373 /* Parse relocations */
374 for (i = 0; i < numShdr - 1; i++) {
375 ElfuScn *ms = secArray[i];
377 switch (ms->shdr.sh_type) {
379 if (me->elfclass == ELFCLASS32) {
381 } else if (me->elfclass == ELFCLASS64) {
386 if (me->elfclass == ELFCLASS32) {
388 } else if (me->elfclass == ELFCLASS64) {
396 /* Sort sections by file offset */
397 qsort(secArray, numShdr - 1, sizeof(*secArray), cmpScnOffs);
400 /* Find PHDR -> Section dependencies (needs sorted sections) */
401 for (i = 0; i < numShdr - 1; i++) {
402 ElfuScn *ms = secArray[i];
404 ElfuPhdr *parent = parentPhdr(me, ms);
407 GElf_Off shaddr = parent->phdr.p_vaddr +
408 (ms->shdr.sh_offset - parent->phdr.p_offset);
410 if (ms->shdr.sh_addr == 0) {
411 ms->shdr.sh_addr = shaddr;
413 assert(ms->shdr.sh_addr == shaddr);
416 CIRCLEQ_INSERT_TAIL(&parent->childScnList, ms, elemChildScn);
418 CIRCLEQ_INSERT_TAIL(&me->orphanScnList, ms, elemChildScn);
432 // TODO: Free data structures
435 ELFU_WARN("elfu_mFromElf: Failed to load file.\n");