1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
/*
* Program to hack in a PT_NOTE program header entry in an ELF file.
* This is needed for OF on RS/6000s to load an image correctly.
* Note that OF needs a program header entry for the note, not an
* ELF section.
*
* Copyright 2000 Paul Mackerras.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Usage: addnote zImage
*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
char arch[] = "PowerPC";
#define N_DESCR 6
unsigned int descr[N_DESCR] = {
0xffffffff, /* real-mode = true */
0x00c00000, /* real-base, i.e. where we expect OF to be */
0xffffffff, /* real-size */
0xffffffff, /* virt-base */
0xffffffff, /* virt-size */
0x4000, /* load-base */
};
unsigned char buf[512];
#define GET_16BE(off) ((buf[off] << 8) + (buf[(off)+1]))
#define GET_32BE(off) ((GET_16BE(off) << 16) + GET_16BE((off)+2))
#define PUT_16BE(off, v) (buf[off] = ((v) >> 8) & 0xff, \
buf[(off) + 1] = (v) & 0xff)
#define PUT_32BE(off, v) (PUT_16BE((off), (v) >> 16), \
PUT_16BE((off) + 2, (v)))
/* Structure of an ELF file */
#define E_IDENT 0 /* ELF header */
#define E_PHOFF 28
#define E_PHENTSIZE 42
#define E_PHNUM 44
#define E_HSIZE 52 /* size of ELF header */
#define EI_MAGIC 0 /* offsets in E_IDENT area */
#define EI_CLASS 4
#define EI_DATA 5
#define PH_TYPE 0 /* ELF program header */
#define PH_OFFSET 4
#define PH_FILESZ 16
#define PH_HSIZE 32 /* size of program header */
#define PT_NOTE 4 /* Program header type = note */
#define ELFCLASS32 1
#define ELFDATA2MSB 2
unsigned char elf_magic[4] = { 0x7f, 'E', 'L', 'F' };
int
main(int ac, char **av)
{
int fd, n, i;
int ph, ps, np;
int nnote, ns;
if (ac != 2) {
fprintf(stderr, "Usage: %s elf-file\n", av[0]);
exit(1);
}
fd = open(av[1], O_RDWR);
if (fd < 0) {
perror(av[1]);
exit(1);
}
nnote = strlen(arch) + 1 + (N_DESCR + 3) * 4;
n = read(fd, buf, sizeof(buf));
if (n < 0) {
perror("read");
exit(1);
}
if (n < E_HSIZE || memcmp(&buf[E_IDENT+EI_MAGIC], elf_magic, 4) != 0)
goto notelf;
if (buf[E_IDENT+EI_CLASS] != ELFCLASS32
|| buf[E_IDENT+EI_DATA] != ELFDATA2MSB) {
fprintf(stderr, "%s is not a big-endian 32-bit ELF image\n",
av[1]);
exit(1);
}
ph = GET_32BE(E_PHOFF);
ps = GET_16BE(E_PHENTSIZE);
np = GET_16BE(E_PHNUM);
if (ph < E_HSIZE || ps < PH_HSIZE || np < 1)
goto notelf;
if (ph + (np + 1) * ps + nnote > n)
goto nospace;
for (i = 0; i < np; ++i) {
if (GET_32BE(ph + PH_TYPE) == PT_NOTE) {
fprintf(stderr, "%s already has a note entry\n",
av[1]);
exit(0);
}
ph += ps;
}
/* XXX check that the area we want to use is all zeroes */
for (i = 0; i < ps + nnote; ++i)
if (buf[ph + i] != 0)
goto nospace;
/* fill in the program header entry */
ns = ph + ps;
PUT_32BE(ph + PH_TYPE, PT_NOTE);
PUT_32BE(ph + PH_OFFSET, ns);
PUT_32BE(ph + PH_FILESZ, nnote);
/* fill in the note area we point to */
/* XXX we should probably make this a proper section */
PUT_32BE(ns, strlen(arch) + 1);
PUT_32BE(ns + 4, N_DESCR * 4);
PUT_32BE(ns + 8, 0x1275);
strcpy(&buf[ns + 12], arch);
ns += 12 + strlen(arch) + 1;
for (i = 0; i < N_DESCR; ++i)
PUT_32BE(ns + i * 4, descr[i]);
/* Update the number of program headers */
PUT_16BE(E_PHNUM, np + 1);
/* write back */
lseek(fd, (long) 0, SEEK_SET);
i = write(fd, buf, n);
if (i < 0) {
perror("write");
exit(1);
}
if (i < n) {
fprintf(stderr, "%s: write truncated\n", av[1]);
exit(1);
}
exit(0);
notelf:
fprintf(stderr, "%s does not appear to be an ELF file\n", av[0]);
exit(1);
nospace:
fprintf(stderr, "sorry, I can't find space in %s to put the note\n",
av[0]);
exit(1);
}
|
