FIRM Loader

firm.c

#include <errno.h>
#include <stdint.h>
#include <stdio.h>

typedef struct {
	long offset;
	void *p;
	size_t size;
	uint8_t hash[32];
} firmSectHdr;

typedef struct {
	uint32_t magic;
	uint32_t unk0;
	void *arm11Ent;
	void *arm9Ent;
	uint8_t unk1[48];
	firmSectHdr sect[4];
	uint8_t sig[256];
} firmHdr;

int loadFirm(const char *file)
{
	firmHdr firm;
	firmSectHdr *p;
	FILE *fp;

	if (file == NULL) {
		errno = EFAULT;
		return -1;
	}

	fp = fopen(file);
	if (fp == NULL)
		return -1;

	if (fread(&firm, sizeof(firm), 1, fp) <= 0) {
		fclose(fp);
		return -1;
	}

	if (firm.magic != htobe32(0x4D524946)) {
		fclose(fp);
		errno = EILSEQ;
		return -1;
	}

	for (p = firm.sect; p != firm.sect + sizeof(firm.sect) / sizeof(firmSectHdr); p++) {
		if (!hdr->size)
			continue;

		if (fseek(fp, hdr->offset, SEEK_SET)) {
			fclose(fp);
			return -1;
		}

		if (fread(hdr->p, hdr->size, 1, fp) <= 0) {
			fclose(fp);
			return -1;
		}
	}

	fclose(fp);

	return 0;
}