/**
* elf_read_from_buffer - read ELF file and sets up ELF header and ELF info
* @buf: Buffer to read ELF file from.
* @len: Size of @buf.
* @ehdr: Pointer to existing struct which will be populated.
* @elf_info: Pointer to existing struct which will be populated.
*
* This function allows reading ELF files with different byte order than
* the kernel, byte-swapping the fields as needed.
*
* Return:
* On success returns 0, and the caller should call elf_free_info(elf_info) to
* free the memory allocated for the section and program headers.
*/
int elf_read_from_buffer(const char *buf, size_t len, struct elfhdr *ehdr,
struct elf_info *elf_info)
{
int ret;
ret = elf_read_ehdr(buf, len, ehdr);
if (ret)
return ret;
elf_info->buffer = buf;
elf_info->ehdr = ehdr;
if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
ret = elf_read_phdrs(buf, len, elf_info);
if (ret)
return ret;
}
if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) {
ret = elf_read_shdrs(buf, len, elf_info);
if (ret) {
kfree(elf_info->proghdrs);
return ret;
}
}
return 0;
}
int ELFManager::elf_get_section_upper_bound(unsigned int type, int *pcount)
{
int ret;
Elf_Shdr shdrs[_ehdr.e_shnum];
ret = elf_read_shdrs(shdrs, _ehdr.e_shnum);
if (ret < 0) {
return -1;
}
int count = 0;
for (unsigned int i=0; i<_ehdr.e_shnum; i++) {
if (shdrs[i].sh_type == type) {
count += shdrs[i].sh_size/shdrs[i].sh_entsize;
}
}
if(pcount != NULL) {
*pcount = count;
}
int needsize = count * sizeof(esymbol *) + count * sizeof(esymbol);
return needsize;
}
int ELFManager::elf_canonicalize_symbol(esymbol **symbol_table, int unsigned type)
{
int ret;
Elf_Shdr shdrs[_ehdr.e_shnum];
ret = elf_read_shdrs(shdrs, _ehdr.e_shnum);
if (ret < 0) {
return -1;
}
unsigned int i = 0;
for (; i<_ehdr.e_shnum; i++) {
if (shdrs[i].sh_type == type) {
break;
}
}
if (i == _ehdr.e_shnum) {
return -1;
}
Elf_Shdr *symtab = &shdrs[i];
//读取name
Elf_Shdr *link = &shdrs[symtab->sh_link];
char *sym_name = (char *)malloc(link->sh_size);
if (sym_name == NULL) {
fprintf(stderr, "malloc error!\n");
return -1;
}
ret = elf_read(link->sh_offset, sym_name, link->sh_size);
if (ret < 0) {
return -1;
}
//读取符号表
int count = symtab->sh_size/symtab->sh_entsize;
esymbol *esym = (esymbol *)&symbol_table[count];
if(_is_32_bit) {
Elf32_Sym syms[count];
ret = elf_read(symtab->sh_offset, syms, symtab->sh_size);
if (ret < 0) {
return -1;
}
for (int idx=0; idx<count; idx++) {
symbol_table[idx] = &esym[idx];
//printf("name:%s!, symbol_table:%llx\n", &sym_name[syms[idx].st_name], symbol_table[idx]);
symbol_table[idx]->name = &sym_name[syms[idx].st_name];
//printf("debug3!\n");
symbol_table[idx]->bind = ELF32_ST_BIND(syms[idx].st_info);
symbol_table[idx]->type = ELF32_ST_TYPE(syms[idx].st_info);
symbol_table[idx]->shndx = syms[idx].st_shndx;
symbol_table[idx]->value = syms[idx].st_value;
symbol_table[idx]->size = syms[idx].st_size;
}
} else {
Elf64_Sym syms[count];
ret = elf_read(symtab->sh_offset, syms, symtab->sh_size);
if (ret < 0) {
return -1;
}
for (int idx=0; idx<count; idx++) {
symbol_table[idx] = &esym[idx];
//printf("name:%s!, symbol_table:%llx\n", &sym_name[syms[idx].st_name], symbol_table[idx]);
symbol_table[idx]->name = &sym_name[syms[idx].st_name];
//printf("debug3!\n");
symbol_table[idx]->bind = ELF64_ST_BIND(syms[idx].st_info);
symbol_table[idx]->type = ELF64_ST_TYPE(syms[idx].st_info);
symbol_table[idx]->shndx = syms[idx].st_shndx;
symbol_table[idx]->value = syms[idx].st_value;
symbol_table[idx]->size = syms[idx].st_size;
}
}
return count;
}
int ELFManager::elf_canonicalize_relsym(erelsym **rel_table, int max_count)
{
int ret;
Elf_Shdr shdrs[_ehdr.e_shnum];
ret = elf_read_shdrs(shdrs, _ehdr.e_shnum);
if (ret < 0) {
return -1;
}
int count = 0;
int cur_idx = 0;
erelsym *erel = (erelsym *)&rel_table[max_count];
for (unsigned int i = 0; i<_ehdr.e_shnum; i++) {
if (shdrs[i].sh_type == SHT_REL || shdrs[i].sh_type == SHT_RELA) {
char *rel = (char *)malloc(shdrs[i].sh_size);
if (rel == NULL) {
fprintf(stderr, "malloc error!\n");
return -1;
}
int num = shdrs[i].sh_size/shdrs[i].sh_entsize;
count += num;
ret = elf_read(shdrs[i].sh_offset, rel, shdrs[i].sh_size);
if (ret < 0) {
return -1;
}
if(_is_32_bit) {
if (shdrs[i].sh_type==SHT_REL) {
Elf32_Rel *prel = (Elf32_Rel *)rel;
for (int idx=0; idx<num; idx++) {
rel_table[cur_idx] = &erel[cur_idx];
rel_table[cur_idx]->offset = prel[idx].r_offset;
rel_table[cur_idx]->type = ELF32_R_TYPE(prel[idx].r_info);
rel_table[cur_idx]->symid = ELF32_R_SYM(prel[idx].r_info);
cur_idx++;
}
} else {
Elf32_Rela *prel = (Elf32_Rela *)rel;
for (int idx=0; idx<num; idx++) {
rel_table[cur_idx] = &erel[cur_idx];
rel_table[cur_idx]->offset = prel[idx].r_offset;
rel_table[cur_idx]->type = ELF32_R_TYPE(prel[idx].r_info);
rel_table[cur_idx]->symid = ELF32_R_SYM(prel[idx].r_info);
//printf("rela[cur_idx:%d] offset:0x%lx, type:%d, symid:%d\n",
// cur_idx, rel_table[cur_idx]->offset, rel_table[cur_idx]->type, rel_table[cur_idx]->symid);
cur_idx++;
}
}
} else {
if (shdrs[i].sh_type==SHT_REL) {
Elf64_Rel *prel = (Elf64_Rel *)rel;
for (int idx=0; idx<num; idx++) {
rel_table[cur_idx] = &erel[cur_idx];
rel_table[cur_idx]->offset = prel[idx].r_offset;
rel_table[cur_idx]->type = ELF64_R_TYPE(prel[idx].r_info);
rel_table[cur_idx]->symid = ELF64_R_SYM(prel[idx].r_info);
cur_idx++;
}
} else {
Elf64_Rela *prel = (Elf64_Rela *)rel;
for (int idx=0; idx<num; idx++) {
rel_table[cur_idx] = &erel[cur_idx];
rel_table[cur_idx]->offset = prel[idx].r_offset;
rel_table[cur_idx]->type = ELF64_R_TYPE(prel[idx].r_info);
rel_table[cur_idx]->symid = ELF64_R_SYM(prel[idx].r_info);
//printf("rela[cur_idx:%d] offset:0x%lx, type:%d, symid:%d\n",
// cur_idx, rel_table[cur_idx]->offset, rel_table[cur_idx]->type, rel_table[cur_idx]->symid);
cur_idx++;
}
}
}
if(rel) {
free(rel);
}
}
}
return count;
}
