struct elf_file_t *elf_open(char *path)
{
struct elf_file_t *elf;
/* Create structure */
elf = calloc(1, sizeof(struct elf_file_t));
if (!elf)
fatal("elf_open: out of memory\n");
/// printf("\n length = %d\n",strlen(path));
/// printf("\n tryng to open %s\n",path);
/* Open file */
elf->f = fopen(path, "rb");
/// printf("\n error no is %d",errno);
if (!elf->f)
fatal("%s: cannot open executable file", path);
if (strlen(path) >= sizeof(elf->path))
fatal("%s: executable file path too long", path);
strcpy(elf->path, path);
/* Get file size */
fseek(elf->f, 0, SEEK_END);
elf->size = ftell(elf->f);
fseek(elf->f, 0, SEEK_SET);
/* Read header, section headers, and program headers. */
elf_debug("\n%s: reading ELF file\n", path);
elf_read_ehdr(elf);
elf_read_shdr(elf);
elf_read_phdr(elf);
/* Return elf file structure */
return elf;
}
/**
* 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_open(const char *filename)
{
//只读模式打开
_fd = open(filename, O_RDONLY);
if (_fd < 0) {
perror("open fail!");
return -1;
}
_filename = filename;
int ret = elf_read(0, _ident, sizeof(_ident));
if (ret < 0) {
fprintf(stderr, "read e_ident error!\n");
return -1;
}
_is_32_bit = (_ident[EI_CLASS] != ELFCLASS64);
ret = elf_read_ehdr(_ehdr);
if(ret != 0) {
return -1;
}
return _fd;
}
int main(int argc, char *argv[])
{
if (argc < 2) {
usage();
goto exit_failure;
}
FILE *fp = fopen(argv[1], "rb");
Elf32_Ehdr ehdr;
if (!elf_read_ehdr(fp, &ehdr)) {
fprintf(stderr, "ERROR: loading ELF\n");
goto exit_close;
}
Elf32_Phdr *phdr;
if (!elf_load_phdr(fp, &ehdr, &phdr)) {
fprintf(stderr, "ERROR: loading ELF Program Header\n");
goto exit_close;
}
Elf32_Shdr *shdr;
if (!elf_load_shdr(fp, &ehdr, &shdr)) {
fprintf(stderr, "ERROR: loading ELF Section Header\n");
goto exit_free_phdr;
}
// Load entire String Table Section
char *shstrtab = elf_load_shstrtab(fp, &ehdr, shdr);
int fstubs_found = 0;
int vstubs_found = 0;
int fstubs_idx = 0, vstubs_idx = 0;
int i;
for (i = 0; i < ehdr.e_shnum && (!fstubs_found || !vstubs_found); i++) {
const char *shstr = shstrtab + shdr[i].sh_name;
if (!fstubs_found) {
if (strcmp(FSTUBS_SECTION, shstr) == 0) {
fstubs_found = 1;
fstubs_idx = i;
}
}
if (!vstubs_found) {
if (strcmp(VSTUBS_SECTION, shstr) == 0) {
vstubs_found = 1;
vstubs_idx = i;
}
}
}
if (!fstubs_found && !vstubs_found) {
fprintf(stderr, "ERROR: the requiered sections "
FSTUBS_SECTION " and " VSTUBS_SECTION
" were not found.\n");
goto exit_free_shstrtab;
} else if (!fstubs_found) {
printf("WARNING: section: " FSTUBS_SECTION
" was not found\n");
} else if (!vstubs_found) {
printf("WARNING: section: " VSTUBS_SECTION
" was not found\n");
}
unsigned char *fbuf = malloc(shdr[fstubs_idx].sh_size);
unsigned char *vbuf = malloc(shdr[vstubs_idx].sh_size);
fseek(fp, shdr[fstubs_idx].sh_offset, SEEK_SET);
fread(fbuf, 1, shdr[fstubs_idx].sh_size, fp);
fseek(fp, shdr[vstubs_idx].sh_offset, SEEK_SET);
fread(vbuf, 1, shdr[vstubs_idx].sh_size, fp);
printf("fstubs size: 0x%08X\n", shdr[fstubs_idx].sh_size);
printf("vstubs size: 0x%08X\n", shdr[vstubs_idx].sh_size);
for (i = 0; i < shdr[fstubs_idx].sh_size; i += 4*4) {
printf("fstub: Lib NID: 0x%08X\n"
" Mod NID: 0x%08X\n"
" Fun NID: 0x%08X\n\n",
*(unsigned int *)(fbuf + i + 0),
*(unsigned int *)(fbuf + i + 4),
*(unsigned int *)(fbuf + i + 8));
}
printf("\n");
for (i = 0; i < shdr[vstubs_idx].sh_size; i += 4*4) {
printf("vstub: Lib NID: 0x%08X\n"
" Mod NID: 0x%08X\n"
" Var NID: 0x%08X\n\n",
*(unsigned int *)(vbuf + i + 0),
*(unsigned int *)(vbuf + i + 4),
*(unsigned int *)(vbuf + i + 8));
}
free(fbuf);
free(vbuf);
free(shstrtab);
elf_free_shdr(&shdr);
elf_free_phdr(&phdr);
fclose(fp);
return EXIT_SUCCESS;
exit_free_shstrtab:
free(shstrtab);
exit_free_shdr:
elf_free_shdr(&shdr);
exit_free_phdr:
elf_free_phdr(&phdr);
exit_close:
fclose(fp);
exit_failure:
return EXIT_FAILURE;
}