/*      $OpenBSD: build.c,v 1.4 2014/07/20 02:03:21 guenther Exp $ */

/*
 * Copyright (c) 2006 Marcus Glocker <mglocker@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/stat.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

//#define VERBOSE               1
#define FILENAME        "bwi-airforce"

struct header {
        char    filename[64];
        int     filesize;
        int     fileoffset;
};

int
main(int argc, char *argv[])
{
        void            *p;
        int              i, j, offset;
        int              fdout, fdin;
        int              nfiles, headersize;
        int              fwsize, totalsize;
        struct header    h[argc - 1];
        struct stat      s;

        if (argc < 2) {
                printf("%s <firmware files>\n", argv[0]);
                exit(1);
        }

        nfiles = argc - 1; /* number of firmware files */
        headersize = sizeof(h) + sizeof(nfiles); /* size of file header */

        /* initialize header struct */
        for (i = 1, j = 0, fwsize = 0; i < argc; i++, j++) {
                bzero(h[j].filename, sizeof(h[j].filename));
                strlcpy(h[j].filename, argv[i], sizeof(h[j].filename));

                if (stat(h[j].filename, &s) == -1)
                        err(1, "header initialization failed");

                h[j].filesize = s.st_size;
                h[j].fileoffset = 0;

                fwsize += h[j].filesize;
#ifdef VERBOSE
                printf("create header entry for %s (%d bytes)\n",
                    h[j].filename, h[j].filesize);
#endif
        }

        /* calculate total file size */
        totalsize = headersize + fwsize;
#if VERBOSE
        printf("\n");
        printf("header size = %d bytes, ", headersize);
        printf("fw size = %d bytes, ", fwsize);
        printf("total file size = %d bytes\n", totalsize);
        printf("\n");
#endif

        /* calculating firmware offsets */
        for (i = 0, offset = headersize; i < nfiles; i++) {
                h[i].fileoffset = offset;
                offset += h[i].filesize;
#ifdef VERBOSE
                printf("offset of %s = %d\n", h[i].filename, h[i].fileoffset);
#endif
        }

        /* open output file */
        if ((fdout = open(FILENAME, O_CREAT|O_TRUNC|O_RDWR, 0644)) == -1)
                err(1, "open output file failed");

        /* host to network byte order */
        for (i = 0; i < nfiles; i++) {
                h[i].filesize = htonl(h[i].filesize);
                h[i].fileoffset = htonl(h[i].fileoffset);
        }
        nfiles = htonl(nfiles);

        /* write header */
        if (write(fdout, &nfiles, sizeof(nfiles)) < 1) {
                int saved_errno = errno;
                close(fdout);
                errc(1, saved_errno, "write header 1 to output file failed");
        }
        if (write(fdout, h, headersize - sizeof(nfiles)) < 1) {
                int saved_errno = errno;
                close(fdout);
                errc(1, saved_errno, "write header 2 to output file failed");
        }

        /* network to host byte order */
        nfiles = ntohl(nfiles);
        for (i = 0; i < nfiles; i++) {
                h[i].filesize = ntohl(h[i].filesize);
                h[i].fileoffset = ntohl(h[i].fileoffset);
        }

        /* write each file */
        for (i = 0; i < nfiles; i++) {
                if ((fdin = open(h[i].filename, O_RDONLY)) == -1) {
                        int saved_errno = errno;
                        close(fdout);
                        errc(1, saved_errno, "open input file failed");
                }
                if ((p = malloc(h[i].filesize)) == NULL) {
                        int saved_errno = errno;
                        close(fdout);
                        close(fdin);
                        errc(1, saved_errno, "malloc");
                }
                if (read(fdin, p, h[i].filesize) < 1) {
                        int saved_errno = errno;
                        free(p);
                        close(fdout);
                        close(fdin);
                        errc(1, saved_errno, "read input file failed");
                }
                if (write(fdout, p, h[i].filesize) < 1) {
                        int saved_errno = errno;
                        free(p);
                        close(fdout);
                        close(fdin);
                        errc(1, saved_errno, "write to output file failed");
                }
                free(p);
                close(fdin);
        }

        close(fdout);

#ifdef VERBOSE
        printf("\n");
#endif

        /* game over */
        printf("wrote %d files to %s (%d bytes).\n",
            nfiles, FILENAME, totalsize);

        return (0);
}