/*      $NetBSD: iplsum.c,v 1.2 2015/12/13 18:38:23 christos Exp $      */

/*
 * Calculate 32bit checksum of IPL and store in a certain location
 *
 * Written in 2003 by ITOH Yasufumi.
 * Public domain
 */

#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>

#ifndef __BIT_TYPES_DEFINED__
typedef unsigned int    uint32_t;
#endif

/* see README.ipl */
#define IPLOFF          (4*1024)        /* 4KB */
#define IPL1SIZE        (4*1024)        /* 4KB */
#define IPL2SIZE        (1*1024)        /* 1KB */
#define IPL2ONDISK      0x0400
#define IPL3SIZE        (3*512)         /* 1.5KB */
#define IPL3ONDISK      0x0A00
#define IPLSIZE         (IPL1SIZE + IPL2SIZE + IPL3SIZE)
#define BOOTSIZE        (IPLOFF + IPLSIZE)
#define BOOTBLOCKSIZE   8192

uint32_t bootblk[BOOTSIZE / sizeof(uint32_t) + 1];

#define SUMOFF          ((IPLOFF + 4) / sizeof(uint32_t))

#ifdef __STDC__
int main(int, char *[]);
#endif

int
main(int argc, char *argv[])
{
        FILE *fp;
        int len;
        uint32_t sum, *p;
        int iploff, iplsumsize;

        if (argc != 3) {
                fprintf(stderr, "usage: %s <input> <output>\n", argv[0]);
                return 1;
        }

        /* read file */
        if ((fp = fopen(argv[1], "rb")) == NULL) {
                perror(argv[1]);
                return 1;
        }
        if ((len = fread(bootblk, 1, sizeof bootblk, fp)) <= IPLOFF) {
                fclose(fp);
                fprintf(stderr, "%s: too short\n", argv[1]);
                return 1;
        } else if (len > BOOTSIZE) {
                fclose(fp);
                fprintf(stderr, "%s: too long (%d vs %d)\n", argv[1], len, BOOTSIZE);
                return 1;
        }
        (void) fclose(fp);

        /* sanity check */
        if ((ntohl(bootblk[0]) & 0xffff0000) != 0x80000000) {
                fprintf(stderr, "%s: bad LIF magic\n", argv[1]);
                return 1;
        }
        iploff = ntohl(bootblk[0xf0 / sizeof(uint32_t)]);
        iplsumsize = ntohl(bootblk[0xf4 / sizeof(uint32_t)]);
        printf("%d bytes free, ipl offset = %d, ipl sum size = %d\n",
            BOOTSIZE - len, iploff, iplsumsize);
        if (iploff != IPLOFF || iplsumsize <= 0 || iplsumsize % 2048 ||
            iploff + iplsumsize > BOOTBLOCKSIZE) {
                fprintf(stderr, "%s: bad ipl offset / size\n", argv[1]);
                return 1;
        }

        /* checksum */
        sum = 0;
        for (p = bootblk + IPLOFF / sizeof(uint32_t);
            p < bootblk + (IPLOFF + IPL1SIZE) / sizeof(uint32_t); p++)
                sum += ntohl(*p);

        bootblk[SUMOFF] = htonl(ntohl(bootblk[SUMOFF]) - sum);

        /* transfer ipl part 2 */
        memcpy(bootblk + IPL2ONDISK / sizeof(uint32_t),
            bootblk + (IPLOFF + IPL1SIZE) / sizeof(uint32_t),
            IPL2SIZE);

        /* transfer ipl part 3 */
        memcpy(bootblk + IPL3ONDISK / sizeof(uint32_t),
            bootblk + (IPLOFF + IPL1SIZE + IPL2SIZE) / sizeof(uint32_t),
            IPL3SIZE);

        /* write file */
        if ((fp = fopen(argv[2], "wb")) == NULL) {
                perror(argv[2]);
                return 1;
        }
        if ((len = fwrite(bootblk, 1, BOOTBLOCKSIZE, fp)) != BOOTBLOCKSIZE) {
                if (len < 0)
                        perror(argv[2]);
                else
                        fprintf(stderr, "%s: short write\n", argv[2]);
                fclose(fp);
                (void) remove(argv[2]);
                return 1;
        }
        if (fclose(fp)) {
                perror(argv[2]);
                (void) remove(argv[2]);
                return 1;
        }

        return 0;
}