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#include "elf.h"
#include <stdio.h>
#include <stdbool.h>
#include <stdint.h>
#include <arpa/inet.h>
static inline bool IsBigEndian(void);
/* Elf Header for Little Endian Machines */
const uint8_t e_ident_le[EI_NIDENT] = {
0x7f, 0x45, 0x4c, 0x46, // ELF Magic Number
BIT_WIDTH, // 32-bit format
_LITTLE_ENDIAN_, // Little Endian
ELF_VERSION, // ELF Version
0x00, // Target OS
0x00, // Target ABI
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 // Padding
};
/* Elf Header for Big Endian Machines */
const uint8_t e_ident_be[EI_NIDENT] = {
0x7f, 0x45, 0x4c, 0x46, // ELF Magic Number
BIT_WIDTH, // 32-bit format
_BIG_ENDIAN_, // Big Endian
ELF_VERSION, // ELF Version
0x00, // Target OS
0x00, // Target ABI
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 // Padding
};
/* ReadElf: Read the elf header into e from file fp */
ElfHeader_t ReadElf(FILE *fp) {
ElfHeader_t e;
fread(&e, sizeof(e), 1, fp);
if (ferror(fp)) {
perror("ReadElf");
}
return e;
}
/* ValidateElf: Validate the elf header for the given system */
bool ValidateElf(ElfHeader_t e) {
const uint8_t * const e_ident = IsBigEndian() ? e_ident_be : e_ident_le;
for (size_t i = 0; i < EI_NIDENT; i++) {
if (e.e_ident[i] != e_ident[i]) {
return false;
}
}
if (e.e_machine != MIPS || e.e_version != ELF_VERSION ||
e.e_type != ET_EXEC || e.e_phentsize != sizeof(ProgramHeader_t)) {
return false;
}
return true;
}
/* ReadProgramHeader: Read n program headers into array p of size n from file
* fp */
void ReadProgramHeader(size_t n, ProgramHeader_t p[n], FILE *fp) {
fread(p, sizeof(ProgramHeader_t), n, fp);
if (ferror(fp)) {
perror("ReadElf");
}
}
static inline bool IsBigEndian(void) {
int32_t x = 10;
return x == htonl(x);
}
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