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 <unistd.h>
15 #include <fcntl.h>
16 #include "rs6000.h"
17
18 #define AOUT_MAGIC 0x010b
19
20 #define get_16be(x) ((((unsigned char *)(x))[0] << 8) \
21 + ((unsigned char *)(x))[1])
22 #define put_16be(x, v) (((unsigned char *)(x))[0] = (v) >> 8, \
23 ((unsigned char *)(x))[1] = (v) & 0xff)
24 #define get_32be(x) ((((unsigned char *)(x))[0] << 24) \
25 + (((unsigned char *)(x))[1] << 16) \
26 + (((unsigned char *)(x))[2] << 8) \
27 + ((unsigned char *)(x))[3])
28
29 int
main(int ac,char ** av)30 main(int ac, char **av)
31 {
32 int fd;
33 int i, nsect;
34 int aoutsz;
35 struct external_filehdr fhdr;
36 AOUTHDR aout;
37 struct external_scnhdr shdr;
38
39 if (ac != 2) {
40 fprintf(stderr, "Usage: hack-coff coff-file\n");
41 exit(1);
42 }
43 if ((fd = open(av[1], 2)) == -1) {
44 perror(av[2]);
45 exit(1);
46 }
47 if (read(fd, &fhdr, sizeof(fhdr)) != sizeof(fhdr))
48 goto readerr;
49 i = get_16be(fhdr.f_magic);
50 if (i != U802TOCMAGIC && i != U802WRMAGIC && i != U802ROMAGIC) {
51 fprintf(stderr, "%s: not an xcoff file\n", av[1]);
52 exit(1);
53 }
54 aoutsz = get_16be(fhdr.f_opthdr);
55 if (read(fd, &aout, aoutsz) != aoutsz)
56 goto readerr;
57 nsect = get_16be(fhdr.f_nscns);
58 for (i = 0; i < nsect; ++i) {
59 if (read(fd, &shdr, sizeof(shdr)) != sizeof(shdr))
60 goto readerr;
61 if (strcmp(shdr.s_name, ".text") == 0) {
62 put_16be(aout.o_snentry, i+1);
63 put_16be(aout.o_sntext, i+1);
64 } else if (strcmp(shdr.s_name, ".data") == 0) {
65 put_16be(aout.o_sndata, i+1);
66 } else if (strcmp(shdr.s_name, ".bss") == 0) {
67 put_16be(aout.o_snbss, i+1);
68 }
69 }
70 put_16be(aout.magic, AOUT_MAGIC);
71 if (lseek(fd, (long) sizeof(struct external_filehdr), 0) == -1
72 || write(fd, &aout, aoutsz) != aoutsz) {
73 fprintf(stderr, "%s: write error\n", av[1]);
74 exit(1);
75 }
76 close(fd);
77 exit(0);
78
79 readerr:
80 fprintf(stderr, "%s: read error or file too short\n", av[1]);
81 exit(1);
82 }
83