1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * hack-coff.c - hack the header of an xcoff file to fill in
4 * a few fields needed by the Open Firmware xcoff loader on
5 * Power Macs but not initialized by objcopy.
6 *
7 * Copyright (C) Paul Mackerras 1997.
8 */
9#include <stdio.h>
10#include <stdlib.h>
11#include <unistd.h>
12#include <fcntl.h>
13#include <string.h>
14#include "rs6000.h"
15
16#define AOUT_MAGIC	0x010b
17
18#define get_16be(x)	((((unsigned char *)(x))[0] << 8) \
19			 + ((unsigned char *)(x))[1])
20#define put_16be(x, v)	(((unsigned char *)(x))[0] = (v) >> 8, \
21			 ((unsigned char *)(x))[1] = (v) & 0xff)
22#define get_32be(x)	((((unsigned char *)(x))[0] << 24) \
23			 + (((unsigned char *)(x))[1] << 16) \
24			 + (((unsigned char *)(x))[2] << 8) \
25			 + ((unsigned char *)(x))[3])
26
27int
28main(int ac, char **av)
29{
30    int fd;
31    int i, nsect;
32    int aoutsz;
33    struct external_filehdr fhdr;
34    AOUTHDR aout;
35    struct external_scnhdr shdr;
36
37    if (ac != 2) {
38	fprintf(stderr, "Usage: hack-coff coff-file\n");
39	exit(1);
40    }
41    if ((fd = open(av[1], 2)) == -1) {
42	perror(av[2]);
43	exit(1);
44    }
45    if (read(fd, &fhdr, sizeof(fhdr)) != sizeof(fhdr))
46	goto readerr;
47    i = get_16be(fhdr.f_magic);
48    if (i != U802TOCMAGIC && i != U802WRMAGIC && i != U802ROMAGIC) {
49	fprintf(stderr, "%s: not an xcoff file\n", av[1]);
50	exit(1);
51    }
52    aoutsz = get_16be(fhdr.f_opthdr);
53    if (read(fd, &aout, aoutsz) != aoutsz)
54	goto readerr;
55    nsect = get_16be(fhdr.f_nscns);
56    for (i = 0; i < nsect; ++i) {
57	if (read(fd, &shdr, sizeof(shdr)) != sizeof(shdr))
58	    goto readerr;
59	if (strcmp(shdr.s_name, ".text") == 0) {
60	    put_16be(aout.o_snentry, i+1);
61	    put_16be(aout.o_sntext, i+1);
62	} else if (strcmp(shdr.s_name, ".data") == 0) {
63	    put_16be(aout.o_sndata, i+1);
64	} else if (strcmp(shdr.s_name, ".bss") == 0) {
65	    put_16be(aout.o_snbss, i+1);
66	}
67    }
68    put_16be(aout.magic, AOUT_MAGIC);
69    if (lseek(fd, (long) sizeof(struct external_filehdr), 0) == -1
70	|| write(fd, &aout, aoutsz) != aoutsz) {
71	fprintf(stderr, "%s: write error\n", av[1]);
72	exit(1);
73    }
74    close(fd);
75    exit(0);
76
77readerr:
78    fprintf(stderr, "%s: read error or file too short\n", av[1]);
79    exit(1);
80}
81