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 
27 int
main(int ac,char ** av)28 main(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 
77 readerr:
78     fprintf(stderr, "%s: read error or file too short\n", av[1]);
79     exit(1);
80 }
81