1// SPDX-License-Identifier: GPL-2.0
2/*
3 *  Copyright (C) 1991, 1992  Linus Torvalds
4 *  Copyright (C) 1997 Martin Mares
5 *  Copyright (C) 2007 H. Peter Anvin
6 */
7
8/*
9 * This file builds a disk-image from three different files:
10 *
11 * - setup: 8086 machine code, sets up system parm
12 * - system: 80386 code for actual system
13 * - zoffset.h: header with ZO_* defines
14 *
15 * It does some checking that all files are of the correct type, and writes
16 * the result to the specified destination, removing headers and padding to
17 * the right amount. It also writes some system data to stdout.
18 */
19
20/*
21 * Changes by tytso to allow root device specification
22 * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
23 * Cross compiling fixes by Gertjan van Wingerde, July 1996
24 * Rewritten by Martin Mares, April 1997
25 * Substantially overhauled by H. Peter Anvin, April 2007
26 */
27
28#include <stdio.h>
29#include <string.h>
30#include <stdlib.h>
31#include <stdarg.h>
32#include <sys/types.h>
33#include <sys/stat.h>
34#include <unistd.h>
35#include <fcntl.h>
36#include <sys/mman.h>
37#include <tools/le_byteshift.h>
38
39typedef unsigned char  u8;
40typedef unsigned short u16;
41typedef unsigned int   u32;
42
43/* Minimal number of setup sectors */
44#define SETUP_SECT_MIN 5
45#define SETUP_SECT_MAX 64
46
47/* This must be large enough to hold the entire setup */
48u8 buf[SETUP_SECT_MAX*512];
49
50static unsigned long _edata;
51
52/*----------------------------------------------------------------------*/
53
54static const u32 crctab32[] = {
55	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
56	0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
57	0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
58	0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
59	0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,
60	0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
61	0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,
62	0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
63	0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
64	0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,
65	0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
66	0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
67	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,
68	0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,
69	0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
70	0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
71	0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,
72	0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
73	0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,
74	0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
75	0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
76	0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,
77	0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,
78	0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
79	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
80	0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,
81	0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
82	0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
83	0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,
84	0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
85	0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,
86	0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
87	0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
88	0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,
89	0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,
90	0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
91	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,
92	0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,
93	0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
94	0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
95	0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,
96	0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
97	0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,
98	0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
99	0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
100	0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
101	0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,
102	0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
103	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,
104	0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,
105	0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
106	0x2d02ef8d
107};
108
109static u32 partial_crc32_one(u8 c, u32 crc)
110{
111	return crctab32[(crc ^ c) & 0xff] ^ (crc >> 8);
112}
113
114static u32 partial_crc32(const u8 *s, int len, u32 crc)
115{
116	while (len--)
117		crc = partial_crc32_one(*s++, crc);
118	return crc;
119}
120
121static void die(const char * str, ...)
122{
123	va_list args;
124	va_start(args, str);
125	vfprintf(stderr, str, args);
126	va_end(args);
127	fputc('\n', stderr);
128	exit(1);
129}
130
131static void usage(void)
132{
133	die("Usage: build setup system zoffset.h image");
134}
135
136/*
137 * Parse zoffset.h and find the entry points. We could just #include zoffset.h
138 * but that would mean tools/build would have to be rebuilt every time. It's
139 * not as if parsing it is hard...
140 */
141#define PARSE_ZOFS(p, sym) do { \
142	if (!strncmp(p, "#define ZO_" #sym " ", 11+sizeof(#sym)))	\
143		sym = strtoul(p + 11 + sizeof(#sym), NULL, 16);		\
144} while (0)
145
146static void parse_zoffset(char *fname)
147{
148	FILE *file;
149	char *p;
150	int c;
151
152	file = fopen(fname, "r");
153	if (!file)
154		die("Unable to open `%s': %m", fname);
155	c = fread(buf, 1, sizeof(buf) - 1, file);
156	if (ferror(file))
157		die("read-error on `zoffset.h'");
158	fclose(file);
159	buf[c] = 0;
160
161	p = (char *)buf;
162
163	while (p && *p) {
164		PARSE_ZOFS(p, _edata);
165
166		p = strchr(p, '\n');
167		while (p && (*p == '\r' || *p == '\n'))
168			p++;
169	}
170}
171
172int main(int argc, char ** argv)
173{
174	unsigned int i, sz, setup_sectors;
175	int c;
176	struct stat sb;
177	FILE *file, *dest;
178	int fd;
179	void *kernel;
180	u32 crc = 0xffffffffUL;
181
182	if (argc != 5)
183		usage();
184	parse_zoffset(argv[3]);
185
186	dest = fopen(argv[4], "w");
187	if (!dest)
188		die("Unable to write `%s': %m", argv[4]);
189
190	/* Copy the setup code */
191	file = fopen(argv[1], "r");
192	if (!file)
193		die("Unable to open `%s': %m", argv[1]);
194	c = fread(buf, 1, sizeof(buf), file);
195	if (ferror(file))
196		die("read-error on `setup'");
197	if (c < 1024)
198		die("The setup must be at least 1024 bytes");
199	if (get_unaligned_le16(&buf[510]) != 0xAA55)
200		die("Boot block hasn't got boot flag (0xAA55)");
201	fclose(file);
202
203	/* Pad unused space with zeros */
204	setup_sectors = (c + 4095) / 4096;
205	setup_sectors *= 8;
206	if (setup_sectors < SETUP_SECT_MIN)
207		setup_sectors = SETUP_SECT_MIN;
208	i = setup_sectors*512;
209	memset(buf+c, 0, i-c);
210
211	/* Open and stat the kernel file */
212	fd = open(argv[2], O_RDONLY);
213	if (fd < 0)
214		die("Unable to open `%s': %m", argv[2]);
215	if (fstat(fd, &sb))
216		die("Unable to stat `%s': %m", argv[2]);
217	if (_edata != sb.st_size)
218		die("Unexpected file size `%s': %u != %u", argv[2], _edata,
219		    sb.st_size);
220	sz = _edata - 4;
221	kernel = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
222	if (kernel == MAP_FAILED)
223		die("Unable to mmap '%s': %m", argv[2]);
224
225	crc = partial_crc32(buf, i, crc);
226	if (fwrite(buf, 1, i, dest) != i)
227		die("Writing setup failed");
228
229	/* Copy the kernel code */
230	crc = partial_crc32(kernel, sz, crc);
231	if (fwrite(kernel, 1, sz, dest) != sz)
232		die("Writing kernel failed");
233
234	/* Write the CRC */
235	put_unaligned_le32(crc, buf);
236	if (fwrite(buf, 1, 4, dest) != 4)
237		die("Writing CRC failed");
238
239	/* Catch any delayed write failures */
240	if (fclose(dest))
241		die("Writing image failed");
242
243	close(fd);
244
245	/* Everything is OK */
246	return 0;
247}
248