5 #include <libelfu/libelfu.h>
8 static char* symstr(ElfuScn *symtab, size_t off)
11 assert(symtab->linkptr);
12 assert(symtab->linkptr->data.d_buf);
13 assert(off < symtab->linkptr->data.d_size);
15 return &(((char*)symtab->linkptr->data.d_buf)[off]);
19 static void parseSymtab32(ElfuScn *ms, ElfuScn**origScnArr)
24 assert(ms->data.d_buf);
28 for (i = 1; (i + 1) * sizeof(Elf32_Sym) <= ms->shdr.sh_size; i++) {
29 Elf32_Sym *cursym = &(((Elf32_Sym*)ms->data.d_buf)[i]);
30 ElfuSym *sym = malloc(sizeof(*sym));
33 sym->name = symstr(ms, cursym->st_name);
34 sym->value = cursym->st_value;
35 sym->size = cursym->st_size;
36 sym->bind = ELF32_ST_BIND(cursym->st_info);
37 sym->type = ELF32_ST_TYPE(cursym->st_info);
38 sym->other = cursym->st_other;
40 switch (cursym->st_shndx) {
45 sym->shndx = cursym->st_shndx;
48 sym->scnptr = origScnArr[cursym->st_shndx - 1];
53 CIRCLEQ_INSERT_TAIL(&ms->symtab.syms, sym, elem);
58 static void parseReltab32(ElfuScn *ms)
63 assert(ms->data.d_buf);
66 for (i = 0; (i + 1) * sizeof(Elf32_Rel) <= ms->shdr.sh_size; i++) {
67 Elf32_Rel *currel = &(((Elf32_Rel*)ms->data.d_buf)[i]);
70 rel = malloc(sizeof(*rel));
73 rel->offset = currel->r_offset;
75 rel->sym = ELF32_R_SYM(currel->r_info);
76 rel->type = ELF32_R_TYPE(currel->r_info);
81 CIRCLEQ_INSERT_TAIL(&ms->reltab.rels, rel, elem);
86 static int cmpScnOffs(const void *ms1, const void *ms2)
91 ElfuScn *s1 = *(ElfuScn**)ms1;
92 ElfuScn *s2 = *(ElfuScn**)ms2;
98 if (s1->shdr.sh_offset < s2->shdr.sh_offset) {
100 } else if (s1->shdr.sh_offset == s2->shdr.sh_offset) {
102 } else /* if (s1->shdr.sh_offset > s2->shdr.sh_offset) */ {
109 static ElfuPhdr* parentPhdr(ElfuElf *me, ElfuScn *ms)
116 CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
117 if (mp->phdr.p_type != PT_LOAD) {
121 if (PHDR_CONTAINS_SCN_IN_MEMORY(&mp->phdr, &ms->shdr)) {
125 /* Give sections a second chance if they do not have any sh_addr
127 /* Actually we don't, because it's ambiguous.
128 * Re-enable for experiments with strangely-formatted files.
129 if (ms->shdr.sh_addr == 0
130 && PHDR_CONTAINS_SCN_IN_FILE(&mp->phdr, &ms->shdr)
131 && OFFS_END(ms->shdr.sh_offset, ms->shdr.sh_size)
132 <= OFFS_END(mp->phdr.p_offset, mp->phdr.p_memsz)) {
142 static ElfuPhdr* modelFromPhdr(GElf_Phdr *phdr)
148 mp = malloc(sizeof(ElfuPhdr));
150 ELFU_WARN("modelFromPhdr: malloc() failed for ElfuPhdr.\n");
156 CIRCLEQ_INIT(&mp->childScnList);
157 CIRCLEQ_INIT(&mp->childPhdrList);
163 static ElfuScn* modelFromSection(Elf_Scn *scn)
169 ms = malloc(sizeof(ElfuScn));
171 ELFU_WARN("modelFromSection: malloc() failed for ElfuScn.\n");
176 assert(gelf_getshdr(scn, &ms->shdr) == &ms->shdr);
179 /* Copy each data part in source segment */
180 ms->data.d_align = 1;
181 ms->data.d_buf = NULL;
183 ms->data.d_type = ELF_T_BYTE;
184 ms->data.d_size = ms->shdr.sh_size;
185 ms->data.d_version = elf_version(EV_NONE);
186 if (ms->shdr.sh_type != SHT_NOBITS
187 && ms->shdr.sh_size > 0) {
190 ms->data.d_buf = malloc(ms->shdr.sh_size);
191 if (!ms->data.d_buf) {
192 ELFU_WARN("modelFromSection: malloc() failed for data buffer (%jx bytes).\n", ms->shdr.sh_size);
196 /* A non-empty section should contain at least one data block. */
197 data = elf_rawdata(scn, NULL);
200 ms->data.d_align = data->d_align;
201 ms->data.d_type = data->d_type;
202 ms->data.d_version = data->d_version;
205 if (data->d_off + data->d_size > ms->shdr.sh_size) {
206 ELFU_WARN("modelFromSection: libelf delivered a bogus data blob. Skipping\n");
208 memcpy(ms->data.d_buf + data->d_off, data->d_buf, data->d_size);
211 data = elf_rawdata(scn, data);
220 CIRCLEQ_INIT(&ms->symtab.syms);
221 CIRCLEQ_INIT(&ms->reltab.rels);
236 ElfuElf* elfu_mFromElf(Elf *e)
240 size_t i, numPhdr, numShdr;
241 ElfuScn **secArray = NULL;
244 if (elfu_eCheck(e)) {
248 me = malloc(sizeof(ElfuElf));
250 ELFU_WARN("elfu_mFromElf: malloc() failed for ElfuElf.\n");
256 CIRCLEQ_INIT(&me->phdrList);
257 CIRCLEQ_INIT(&me->orphanScnList);
260 me->elfclass = gelf_getclass(e);
261 assert(me->elfclass != ELFCLASSNONE);
262 assert(gelf_getehdr(e, &me->ehdr) == &me->ehdr);
265 /* Get the section string table index */
266 if (elf_getshdrstrndx(e, &shstrndx) != 0) {
272 assert(!elf_getphdrnum(e, &numPhdr));
273 for (i = 0; i < numPhdr; i++) {
277 assert(gelf_getphdr(e, i, &phdr) == &phdr);
279 mp = modelFromPhdr(&phdr);
284 CIRCLEQ_INSERT_TAIL(&me->phdrList, mp, elem);
290 /* Find PHDR -> PHDR dependencies (needs sorted sections) */
291 CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
294 if (mp->phdr.p_type != PT_LOAD) {
298 CIRCLEQ_FOREACH(mp2, &me->phdrList, elem) {
303 if (mp->phdr.p_vaddr <= mp2->phdr.p_vaddr
304 && OFFS_END(mp2->phdr.p_vaddr, mp2->phdr.p_memsz) <= OFFS_END(mp->phdr.p_vaddr, mp->phdr.p_memsz)) {
305 CIRCLEQ_INSERT_TAIL(&mp->childPhdrList, mp2, elemChildPhdr);
313 assert(!elf_getshdrnum(e, &numShdr));
315 secArray = malloc((numShdr - 1) * sizeof(*secArray));
317 ELFU_WARN("elfu_mFromElf: malloc() failed for secArray.\n");
321 for (i = 1; i < numShdr; i++) {
325 scn = elf_getscn(e, i);
328 ms = modelFromSection(scn);
341 /* Find sh_link and sh_info dependencies (needs sections in original order) */
342 for (i = 0; i < numShdr - 1; i++) {
343 ElfuScn *ms = secArray[i];
345 switch (ms->shdr.sh_type) {
348 if (ms->shdr.sh_info > 0) {
349 ms->infoptr = secArray[ms->shdr.sh_info - 1];
357 case SHT_GNU_verneed:
358 if (ms->shdr.sh_link > 0) {
359 ms->linkptr = secArray[ms->shdr.sh_link - 1];
365 /* Parse symtabs (needs sections in original order) */
366 for (i = 0; i < numShdr - 1; i++) {
367 ElfuScn *ms = secArray[i];
369 switch (ms->shdr.sh_type) {
372 if (me->elfclass == ELFCLASS32) {
373 parseSymtab32(ms, secArray);
374 } else if (me->elfclass == ELFCLASS64) {
382 /* Parse relocations */
383 for (i = 0; i < numShdr - 1; i++) {
384 ElfuScn *ms = secArray[i];
386 switch (ms->shdr.sh_type) {
388 if (me->elfclass == ELFCLASS32) {
390 } else if (me->elfclass == ELFCLASS64) {
395 if (me->elfclass == ELFCLASS32) {
397 } else if (me->elfclass == ELFCLASS64) {
405 /* Sort sections by file offset */
406 qsort(secArray, numShdr - 1, sizeof(*secArray), cmpScnOffs);
409 /* Find PHDR -> Section dependencies (needs sorted sections) */
410 for (i = 0; i < numShdr - 1; i++) {
411 ElfuScn *ms = secArray[i];
413 ElfuPhdr *parent = parentPhdr(me, ms);
416 GElf_Off shaddr = parent->phdr.p_vaddr +
417 (ms->shdr.sh_offset - parent->phdr.p_offset);
419 if (ms->shdr.sh_addr == 0) {
420 ms->shdr.sh_addr = shaddr;
422 assert(ms->shdr.sh_addr == shaddr);
425 CIRCLEQ_INSERT_TAIL(&parent->childScnList, ms, elemChildScn);
427 CIRCLEQ_INSERT_TAIL(&me->orphanScnList, ms, elemChildScn);
441 // TODO: Free data structures
444 ELFU_WARN("elfu_mFromElf: Failed to load file.\n");