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 = cursym->st_name;
34 sym->nameptr = symstr(ms, cursym->st_name);
35 sym->value = cursym->st_value;
36 sym->size = cursym->st_size;
37 sym->bind = ELF32_ST_BIND(cursym->st_info);
38 sym->type = ELF32_ST_TYPE(cursym->st_info);
39 sym->other = cursym->st_other;
41 switch (cursym->st_shndx) {
46 sym->shndx = cursym->st_shndx;
49 sym->scnptr = origScnArr[cursym->st_shndx - 1];
54 CIRCLEQ_INSERT_TAIL(&ms->symtab.syms, sym, elem);
59 static void parseReltab32(ElfuScn *ms)
64 assert(ms->data.d_buf);
67 for (i = 0; (i + 1) * sizeof(Elf32_Rel) <= ms->shdr.sh_size; i++) {
68 Elf32_Rel *currel = &(((Elf32_Rel*)ms->data.d_buf)[i]);
71 rel = malloc(sizeof(*rel));
74 rel->offset = currel->r_offset;
76 rel->sym = ELF32_R_SYM(currel->r_info);
77 rel->type = ELF32_R_TYPE(currel->r_info);
82 CIRCLEQ_INSERT_TAIL(&ms->reltab.rels, rel, elem);
87 static int cmpScnOffs(const void *ms1, const void *ms2)
92 ElfuScn *s1 = *(ElfuScn**)ms1;
93 ElfuScn *s2 = *(ElfuScn**)ms2;
99 if (s1->shdr.sh_offset < s2->shdr.sh_offset) {
101 } else if (s1->shdr.sh_offset == s2->shdr.sh_offset) {
103 } else /* if (s1->shdr.sh_offset > s2->shdr.sh_offset) */ {
110 static ElfuPhdr* parentPhdr(ElfuElf *me, ElfuScn *ms)
117 CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
118 if (mp->phdr.p_type != PT_LOAD) {
122 if (PHDR_CONTAINS_SCN_IN_MEMORY(&mp->phdr, &ms->shdr)) {
126 /* Give sections a second chance if they do not have any sh_addr
128 /* Actually we don't, because it's ambiguous.
129 * Re-enable for experiments with strangely-formatted files.
130 if (ms->shdr.sh_addr == 0
131 && PHDR_CONTAINS_SCN_IN_FILE(&mp->phdr, &ms->shdr)
132 && OFFS_END(ms->shdr.sh_offset, ms->shdr.sh_size)
133 <= OFFS_END(mp->phdr.p_offset, mp->phdr.p_memsz)) {
143 static ElfuPhdr* modelFromPhdr(GElf_Phdr *phdr)
149 mp = malloc(sizeof(ElfuPhdr));
151 ELFU_WARN("modelFromPhdr: malloc() failed for ElfuPhdr.\n");
157 CIRCLEQ_INIT(&mp->childScnList);
158 CIRCLEQ_INIT(&mp->childPhdrList);
164 static ElfuScn* modelFromSection(Elf_Scn *scn)
170 ms = malloc(sizeof(ElfuScn));
172 ELFU_WARN("modelFromSection: malloc() failed for ElfuScn.\n");
177 assert(gelf_getshdr(scn, &ms->shdr) == &ms->shdr);
180 /* Copy each data part in source segment */
181 ms->data.d_align = 1;
182 ms->data.d_buf = NULL;
184 ms->data.d_type = ELF_T_BYTE;
185 ms->data.d_size = ms->shdr.sh_size;
186 ms->data.d_version = elf_version(EV_NONE);
187 if (ms->shdr.sh_type != SHT_NOBITS
188 && ms->shdr.sh_size > 0) {
191 ms->data.d_buf = malloc(ms->shdr.sh_size);
192 if (!ms->data.d_buf) {
193 ELFU_WARN("modelFromSection: malloc() failed for data buffer (%jx bytes).\n", ms->shdr.sh_size);
197 /* A non-empty section should contain at least one data block. */
198 data = elf_rawdata(scn, NULL);
201 ms->data.d_align = data->d_align;
202 ms->data.d_type = data->d_type;
203 ms->data.d_version = data->d_version;
206 if (data->d_off + data->d_size > ms->shdr.sh_size) {
207 ELFU_WARN("modelFromSection: libelf delivered a bogus data blob. Skipping\n");
209 memcpy(ms->data.d_buf + data->d_off, data->d_buf, data->d_size);
212 data = elf_rawdata(scn, data);
221 CIRCLEQ_INIT(&ms->symtab.syms);
222 CIRCLEQ_INIT(&ms->reltab.rels);
237 ElfuElf* elfu_mFromElf(Elf *e)
241 size_t i, numPhdr, numShdr;
242 ElfuScn **secArray = NULL;
245 if (elfu_eCheck(e)) {
249 me = malloc(sizeof(ElfuElf));
251 ELFU_WARN("elfu_mFromElf: malloc() failed for ElfuElf.\n");
257 CIRCLEQ_INIT(&me->phdrList);
258 CIRCLEQ_INIT(&me->orphanScnList);
262 me->elfclass = gelf_getclass(e);
263 assert(me->elfclass != ELFCLASSNONE);
264 assert(gelf_getehdr(e, &me->ehdr) == &me->ehdr);
267 /* Get the section string table index */
268 if (elf_getshdrstrndx(e, &shstrndx) != 0) {
274 assert(!elf_getphdrnum(e, &numPhdr));
275 for (i = 0; i < numPhdr; i++) {
279 assert(gelf_getphdr(e, i, &phdr) == &phdr);
281 mp = modelFromPhdr(&phdr);
286 CIRCLEQ_INSERT_TAIL(&me->phdrList, mp, elem);
292 /* Find PHDR -> PHDR dependencies (needs sorted sections) */
293 CIRCLEQ_FOREACH(mp, &me->phdrList, elem) {
296 if (mp->phdr.p_type != PT_LOAD) {
300 CIRCLEQ_FOREACH(mp2, &me->phdrList, elem) {
305 if (mp->phdr.p_vaddr <= mp2->phdr.p_vaddr
306 && OFFS_END(mp2->phdr.p_vaddr, mp2->phdr.p_memsz) <= OFFS_END(mp->phdr.p_vaddr, mp->phdr.p_memsz)) {
307 CIRCLEQ_INSERT_TAIL(&mp->childPhdrList, mp2, elemChildPhdr);
315 assert(!elf_getshdrnum(e, &numShdr));
317 secArray = malloc((numShdr - 1) * sizeof(*secArray));
319 ELFU_WARN("elfu_mFromElf: malloc() failed for secArray.\n");
323 for (i = 1; i < numShdr; i++) {
327 scn = elf_getscn(e, i);
330 ms = modelFromSection(scn);
343 /* Find sh_link and sh_info dependencies (needs sections in original order) */
344 for (i = 0; i < numShdr - 1; i++) {
345 ElfuScn *ms = secArray[i];
347 switch (ms->shdr.sh_type) {
350 if (ms->shdr.sh_info > 0) {
351 ms->infoptr = secArray[ms->shdr.sh_info - 1];
359 case SHT_GNU_verneed:
360 if (ms->shdr.sh_link > 0) {
361 ms->linkptr = secArray[ms->shdr.sh_link - 1];
367 /* Parse symtabs (needs sections in original order) */
368 for (i = 0; i < numShdr - 1; i++) {
369 ElfuScn *ms = secArray[i];
371 switch (ms->shdr.sh_type) {
375 if (me->elfclass == ELFCLASS32) {
376 parseSymtab32(ms, secArray);
377 } else if (me->elfclass == ELFCLASS64) {
385 /* Parse relocations */
386 for (i = 0; i < numShdr - 1; i++) {
387 ElfuScn *ms = secArray[i];
389 switch (ms->shdr.sh_type) {
391 if (me->elfclass == ELFCLASS32) {
393 } else if (me->elfclass == ELFCLASS64) {
398 if (me->elfclass == ELFCLASS32) {
400 } else if (me->elfclass == ELFCLASS64) {
408 /* Sort sections by file offset */
409 qsort(secArray, numShdr - 1, sizeof(*secArray), cmpScnOffs);
412 /* Find PHDR -> Section dependencies (needs sorted sections) */
413 for (i = 0; i < numShdr - 1; i++) {
414 ElfuScn *ms = secArray[i];
416 ElfuPhdr *parent = parentPhdr(me, ms);
419 GElf_Off shaddr = parent->phdr.p_vaddr +
420 (ms->shdr.sh_offset - parent->phdr.p_offset);
422 if (ms->shdr.sh_addr == 0) {
423 ms->shdr.sh_addr = shaddr;
425 assert(ms->shdr.sh_addr == shaddr);
428 CIRCLEQ_INSERT_TAIL(&parent->childScnList, ms, elemChildScn);
430 CIRCLEQ_INSERT_TAIL(&me->orphanScnList, ms, elemChildScn);
444 // TODO: Free data structures
447 ELFU_WARN("elfu_mFromElf: Failed to load file.\n");