elf32: more portable implementation.
The old implementation only worked on little-endian machines, and relied on a particular struct layout.
This commit is contained in:
Daniel Beer
parent
6fd161faa7
commit
f44d9d5281
129
formats/elf32.c
129
formats/elf32.c
|
|
@ -44,11 +44,93 @@ struct elf32_info {
|
|||
int string_len;
|
||||
};
|
||||
|
||||
static int parse_ehdr(Elf32_Ehdr *e, FILE *in)
|
||||
{
|
||||
uint8_t data[52];
|
||||
|
||||
if (fread(data, sizeof(data), 1, in) != 1)
|
||||
return -1;
|
||||
|
||||
memcpy(e->e_ident, data, EI_NIDENT);
|
||||
e->e_type = LE_WORD(data, 16);
|
||||
e->e_machine = LE_WORD(data, 18);
|
||||
e->e_version = LE_LONG(data, 20);
|
||||
e->e_entry = LE_LONG(data, 24);
|
||||
e->e_phoff = LE_LONG(data, 28);
|
||||
e->e_shoff = LE_LONG(data, 32);
|
||||
e->e_flags = LE_LONG(data, 36);
|
||||
e->e_ehsize = LE_WORD(data, 40);
|
||||
e->e_phentsize = LE_WORD(data, 42);
|
||||
e->e_phnum = LE_WORD(data, 44);
|
||||
e->e_shentsize = LE_WORD(data, 46);
|
||||
e->e_shnum = LE_WORD(data, 48);
|
||||
e->e_shstrndx = LE_WORD(data, 50);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int parse_phdr(Elf32_Phdr *p, FILE *in)
|
||||
{
|
||||
uint8_t data[32];
|
||||
|
||||
if (fread(data, sizeof(data), 1, in) != 1)
|
||||
return -1;
|
||||
|
||||
p->p_type = LE_LONG(data, 0);
|
||||
p->p_offset = LE_LONG(data, 4);
|
||||
p->p_vaddr = LE_LONG(data, 8);
|
||||
p->p_paddr = LE_LONG(data, 12);
|
||||
p->p_filesz = LE_LONG(data, 16);
|
||||
p->p_memsz = LE_LONG(data, 20);
|
||||
p->p_flags = LE_LONG(data, 24);
|
||||
p->p_align = LE_LONG(data, 28);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int parse_shdr(Elf32_Shdr *s, FILE *in)
|
||||
{
|
||||
uint8_t data[40];
|
||||
|
||||
if (fread(data, sizeof(data), 1, in) != 1)
|
||||
return -1;
|
||||
|
||||
s->sh_name = LE_LONG(data, 0);
|
||||
s->sh_type = LE_LONG(data, 4);
|
||||
s->sh_flags = LE_LONG(data, 8);
|
||||
s->sh_addr = LE_LONG(data, 12);
|
||||
s->sh_offset = LE_LONG(data, 16);
|
||||
s->sh_size = LE_LONG(data, 20);
|
||||
s->sh_link = LE_LONG(data, 24);
|
||||
s->sh_info = LE_LONG(data, 28);
|
||||
s->sh_addralign = LE_LONG(data, 32);
|
||||
s->sh_entsize = LE_LONG(data, 36);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int parse_sym(Elf32_Sym *s, FILE *in)
|
||||
{
|
||||
uint8_t data[16];
|
||||
|
||||
if (fread(data, sizeof(data), 1, in) != 1)
|
||||
return -1;
|
||||
|
||||
s->st_name = LE_LONG(data, 0);
|
||||
s->st_value = LE_LONG(data, 4);
|
||||
s->st_size = LE_LONG(data, 8);
|
||||
s->st_info = data[12];
|
||||
s->st_other = data[13];
|
||||
s->st_shndx = LE_WORD(data, 14);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int read_ehdr(struct elf32_info *info, FILE *in)
|
||||
{
|
||||
/* Read and check the ELF header */
|
||||
rewind(in);
|
||||
if (fread(&info->file_ehdr, sizeof(info->file_ehdr), 1, in) == 0) {
|
||||
if (parse_ehdr(&info->file_ehdr, in) < 0) {
|
||||
pr_error("elf32: couldn't read ELF header");
|
||||
return -1;
|
||||
}
|
||||
|
|
@ -79,8 +161,7 @@ static int read_phdr(struct elf32_info *info, FILE *in)
|
|||
return -1;
|
||||
}
|
||||
|
||||
if (fread(&info->file_phdrs[i],
|
||||
sizeof(info->file_phdrs[0]), 1, in) == 0) {
|
||||
if (parse_phdr(&info->file_phdrs[i], in) < 0) {
|
||||
printc_err("elf32: can't read phdr %d: %s\n",
|
||||
i, last_error());
|
||||
return -1;
|
||||
|
|
@ -108,8 +189,7 @@ static int read_shdr(struct elf32_info *info, FILE *in)
|
|||
return -1;
|
||||
}
|
||||
|
||||
if (fread(&info->file_shdrs[i],
|
||||
sizeof(info->file_shdrs[0]), 1, in) == 0) {
|
||||
if (parse_shdr(&info->file_shdrs[i], in) < 0) {
|
||||
printc_err("elf32: can't read shdr %d: %s\n",
|
||||
i, last_error());
|
||||
return -1;
|
||||
|
|
@ -217,7 +297,7 @@ static int load_strings(struct elf32_info *info, FILE *in, Elf32_Shdr *s)
|
|||
return -1;
|
||||
}
|
||||
|
||||
if (!fread(info->string_tab, 1, info->string_len, in)) {
|
||||
if (!fread(info->string_tab, info->string_len, 1, in)) {
|
||||
if (ferror(in)) {
|
||||
pr_error("elf32: error reading strings");
|
||||
return -1;
|
||||
|
|
@ -296,37 +376,29 @@ static Elf32_Shdr *find_shdr(struct elf32_info *info, Elf32_Word type)
|
|||
static int syms_load_syms(struct elf32_info *info, FILE *in,
|
||||
Elf32_Shdr *s)
|
||||
{
|
||||
Elf32_Sym syms[N_SYMS];
|
||||
int len = s->sh_size / sizeof(syms[0]);
|
||||
int len = s->sh_size / 16;
|
||||
int i;
|
||||
|
||||
if (fseek(in, s->sh_offset, SEEK_SET) < 0) {
|
||||
pr_error("elf32: can't seek to symbols");
|
||||
return -1;
|
||||
}
|
||||
|
||||
while (len) {
|
||||
int req = N_SYMS > len ? len : N_SYMS;
|
||||
int count = fread(syms, sizeof(syms[0]), req, in);
|
||||
int i;
|
||||
for (i = 0; i < len; i++) {
|
||||
Elf32_Sym y;
|
||||
int st;
|
||||
const char *name;
|
||||
|
||||
if (!count) {
|
||||
printc_err("elf32: eof reading symbols\n");
|
||||
return -1;
|
||||
}
|
||||
|
||||
if (count < 0) {
|
||||
if (parse_sym(&y, in) < 0) {
|
||||
pr_error("elf32: error reading symbols");
|
||||
return -1;
|
||||
}
|
||||
|
||||
for (i = 0; i < count; i++) {
|
||||
Elf32_Sym *y = &syms[i];
|
||||
int st = ELF32_ST_TYPE(y->st_info);
|
||||
const char *name = info->string_tab + y->st_name;
|
||||
st = ELF32_ST_TYPE(y.st_info);
|
||||
name = info->string_tab + y.st_name;
|
||||
|
||||
if (y->st_name > info->string_len) {
|
||||
printc_err("elf32: symbol out of "
|
||||
"bounds\n");
|
||||
if (y.st_name > info->string_len) {
|
||||
printc_err("elf32: symbol out of bounds\n");
|
||||
return -1;
|
||||
}
|
||||
|
||||
|
|
@ -334,14 +406,11 @@ static int syms_load_syms(struct elf32_info *info, FILE *in,
|
|||
(st == STT_OBJECT || st == STT_FUNC ||
|
||||
st == STT_SECTION || st == STT_COMMON ||
|
||||
st == STT_TLS) &&
|
||||
stab_set(info->string_tab + y->st_name,
|
||||
y->st_value) < 0)
|
||||
stab_set(info->string_tab + y.st_name,
|
||||
y.st_value) < 0)
|
||||
return -1;
|
||||
}
|
||||
|
||||
len -= count;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue