1/*
2 * hack-coff.c - hack the header of an xcoff file to fill in
3 * a few fields needed by the Open Firmware xcoff loader on
4 * Power Macs but not initialized by objcopy.
5 *
6 * Copyright (C) Paul Mackerras 1997.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 */
13#include <stdio.h>
14#include <stdlib.h>
15#include <unistd.h>
16#include <fcntl.h>
17#include <string.h>
18#include "rs6000.h"
19
20#define AOUT_MAGIC	0x010b
21
22#define get_16be(x)	((((unsigned char *)(x))[0] << 8) \
23			 + ((unsigned char *)(x))[1])
24#define put_16be(x, v)	(((unsigned char *)(x))[0] = (v) >> 8, \
25			 ((unsigned char *)(x))[1] = (v) & 0xff)
26#define get_32be(x)	((((unsigned char *)(x))[0] << 24) \
27			 + (((unsigned char *)(x))[1] << 16) \
28			 + (((unsigned char *)(x))[2] << 8) \
29			 + ((unsigned char *)(x))[3])
30
31int
32main(int ac, char **av)
33{
34    int fd;
35    int i, nsect;
36    int aoutsz;
37    struct external_filehdr fhdr;
38    AOUTHDR aout;
39    struct external_scnhdr shdr;
40
41    if (ac != 2) {
42	fprintf(stderr, "Usage: hack-coff coff-file\n");
43	exit(1);
44    }
45    if ((fd = open(av[1], 2)) == -1) {
46	perror(av[2]);
47	exit(1);
48    }
49    if (read(fd, &fhdr, sizeof(fhdr)) != sizeof(fhdr))
50	goto readerr;
51    i = get_16be(fhdr.f_magic);
52    if (i != U802TOCMAGIC && i != U802WRMAGIC && i != U802ROMAGIC) {
53	fprintf(stderr, "%s: not an xcoff file\n", av[1]);
54	exit(1);
55    }
56    aoutsz = get_16be(fhdr.f_opthdr);
57    if (read(fd, &aout, aoutsz) != aoutsz)
58	goto readerr;
59    nsect = get_16be(fhdr.f_nscns);
60    for (i = 0; i < nsect; ++i) {
61	if (read(fd, &shdr, sizeof(shdr)) != sizeof(shdr))
62	    goto readerr;
63	if (strcmp(shdr.s_name, ".text") == 0) {
64	    put_16be(aout.o_snentry, i+1);
65	    put_16be(aout.o_sntext, i+1);
66	} else if (strcmp(shdr.s_name, ".data") == 0) {
67	    put_16be(aout.o_sndata, i+1);
68	} else if (strcmp(shdr.s_name, ".bss") == 0) {
69	    put_16be(aout.o_snbss, i+1);
70	}
71    }
72    put_16be(aout.magic, AOUT_MAGIC);
73    if (lseek(fd, (long) sizeof(struct external_filehdr), 0) == -1
74	|| write(fd, &aout, aoutsz) != aoutsz) {
75	fprintf(stderr, "%s: write error\n", av[1]);
76	exit(1);
77    }
78    close(fd);
79    exit(0);
80
81readerr:
82    fprintf(stderr, "%s: read error or file too short\n", av[1]);
83    exit(1);
84}
85