mkimage.c

#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>

#define PART_MAGIC        0x58881688
#define BLK_SIZE          512

typedef union {
    struct {
        unsigned int magic;        /* partition magic */
        unsigned int dsize;        /* partition data size */
        char         name[32];     /* partition name */
    } info;
    unsigned char data[BLK_SIZE];
} part_hdr_t;

unsigned int filesize(char *name)
{
    struct stat statbuf;

    if(stat(name, &statbuf) != 0) {
        fprintf(stderr, "Cannot open file %s\n", name);
        exit(0);
    }
    return statbuf.st_size;
}

char *readfile(char *name, unsigned int size)
{
    FILE *f;
    char *buf;

    f = fopen(name, "rb");
    if(f == NULL) {
        fprintf(stderr, "Cannot open file %s\n", name);
        exit(0);
    }
    buf = (char *)malloc(size);
    if (!buf) {
        fprintf(stderr, "error while malloc(%ld)\n", size);
        fclose(f);
        exit(1);
    }
    if(fread(buf, 1, size, f) != size) {
        fprintf(stderr, "Error while reading file %s\n", name);
        fclose(f);
        exit(0);
    }
    fclose(f);
    return buf;
}

int main(int argc, char *argv[])
{
    part_hdr_t part_hdr;
    char *img;
    uint32_t imgsize;

    if(argc != 3) {
        fprintf(stderr, "\nUsage: ./mkimage <image_file> <image_name>\n\n");
        fprintf(stderr, "  e.g. <image_file>: Image, rootfs.gz\n");
        fprintf(stderr, "  e.g. <image_name>: KERNEL, ROOTFS\n\n");
        return 0;
    }

    memset(&part_hdr, 0xff, sizeof(part_hdr_t));

    part_hdr.info.magic = PART_MAGIC;
    part_hdr.info.dsize = filesize(argv[1]);
    strncpy(part_hdr.info.name, argv[2], sizeof(part_hdr.info.name));

    /*
    fprintf(stderr, "[MKIMAGE] '%s'(%d bytes)\n", part_hdr.info.name,
        part_hdr.info.dsize);
    */

    img = readfile(argv[1], part_hdr.info.dsize);

    write(STDOUT_FILENO, &part_hdr, sizeof(part_hdr_t));
    write(STDOUT_FILENO, img, part_hdr.info.dsize);

    return 0;
}