1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/tools/build.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
8 /*
9 * This file builds a disk-image from three different files:
10 *
11 * - bootsect: exactly 512 bytes of 8086 machine code, loads the rest
12 * - setup: 8086 machine code, sets up system parm
13 * - system: 80386 code for actual system
14 *
15 * It does some checking that all files are of the correct type, and
16 * just writes the result to stdout, removing headers and padding to
17 * the right amount. It also writes some system data to stderr.
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 */
25
26 #include <stdio.h> /* fprintf */
27 #include <string.h>
28 #include <stdlib.h> /* contains exit */
29 #include <sys/types.h> /* unistd.h needs this */
30 #include <sys/stat.h>
31 #include <sys/sysmacros.h>
32 #include <unistd.h> /* contains read/write */
33 #include <fcntl.h>
34 #include <errno.h>
35
36 #define MINIX_HEADER 32
37
38 #define N_MAGIC_OFFSET 1024
39 #ifndef __BFD__
40 static int GCC_HEADER = sizeof(struct exec);
41 #endif
42
43 #ifdef __BIG_KERNEL__
44 #define SYS_SIZE 0xffff
45 #else
46 #define SYS_SIZE DEF_SYSSIZE
47 #endif
48
49 #define DEFAULT_MAJOR_ROOT 0
50 #define DEFAULT_MINOR_ROOT 0
51
52 /* max nr of sectors of setup: don't change unless you also change
53 * bootsect etc */
54 #define SETUP_SECTS 4
55
56 #define STRINGIFY(x) #x
57
58 typedef union {
59 int i;
60 long l;
61 short s[2];
62 char b[4];
63 } conv;
64
intel_long(long l)65 long intel_long(long l)
66 {
67 conv t;
68
69 t.b[0] = l & 0xff; l >>= 8;
70 t.b[1] = l & 0xff; l >>= 8;
71 t.b[2] = l & 0xff; l >>= 8;
72 t.b[3] = l & 0xff; l >>= 8;
73 return t.l;
74 }
75
intel_int(int i)76 int intel_int(int i)
77 {
78 conv t;
79
80 t.b[0] = i & 0xff; i >>= 8;
81 t.b[1] = i & 0xff; i >>= 8;
82 t.b[2] = i & 0xff; i >>= 8;
83 t.b[3] = i & 0xff; i >>= 8;
84 return t.i;
85 }
86
intel_short(short l)87 short intel_short(short l)
88 {
89 conv t;
90
91 t.b[0] = l & 0xff; l >>= 8;
92 t.b[1] = l & 0xff; l >>= 8;
93 return t.s[0];
94 }
95
die(const char * str)96 void die(const char * str)
97 {
98 fprintf(stderr,"%s\n",str);
99 exit(1);
100 }
101
usage(void)102 void usage(void)
103 {
104 die("Usage: build bootsect setup system [rootdev] [> image]");
105 }
106
main(int argc,char ** argv)107 int main(int argc, char ** argv)
108 {
109 int i,c,id,sz,tmp_int;
110 unsigned long sys_size, tmp_long;
111 char buf[1024];
112 #ifndef __BFD__
113 struct exec *ex = (struct exec *)buf;
114 #endif
115 char major_root, minor_root;
116 struct stat sb;
117 unsigned char setup_sectors;
118
119 if ((argc < 4) || (argc > 5))
120 usage();
121 if (argc > 4) {
122 if (!strcmp(argv[4], "CURRENT")) {
123 if (stat("/", &sb)) {
124 perror("/");
125 die("Couldn't stat /");
126 }
127 major_root = major(sb.st_dev);
128 minor_root = minor(sb.st_dev);
129 } else if (strcmp(argv[4], "FLOPPY")) {
130 if (stat(argv[4], &sb)) {
131 perror(argv[4]);
132 die("Couldn't stat root device.");
133 }
134 major_root = major(sb.st_rdev);
135 minor_root = minor(sb.st_rdev);
136 } else {
137 major_root = 0;
138 minor_root = 0;
139 }
140 } else {
141 major_root = DEFAULT_MAJOR_ROOT;
142 minor_root = DEFAULT_MINOR_ROOT;
143 }
144 fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
145 for (i=0;i<sizeof buf; i++) buf[i]=0;
146 if ((id=open(argv[1],O_RDONLY,0))<0)
147 die("Unable to open 'boot'");
148 if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
149 die("Unable to read header of 'boot'");
150 if (((long *) buf)[0]!=intel_long(0x04100301))
151 die("Non-Minix header of 'boot'");
152 if (((long *) buf)[1]!=intel_long(MINIX_HEADER))
153 die("Non-Minix header of 'boot'");
154 if (((long *) buf)[3] != 0)
155 die("Illegal data segment in 'boot'");
156 if (((long *) buf)[4] != 0)
157 die("Illegal bss in 'boot'");
158 if (((long *) buf)[5] != 0)
159 die("Non-Minix header of 'boot'");
160 if (((long *) buf)[7] != 0)
161 die("Illegal symbol table in 'boot'");
162 i=read(id,buf,sizeof buf);
163 fprintf(stderr,"Boot sector %d bytes.\n",i);
164 if (i != 512)
165 die("Boot block must be exactly 512 bytes");
166 if ((*(unsigned short *)(buf+510)) != (unsigned short)intel_short(0xAA55))
167 die("Boot block hasn't got boot flag (0xAA55)");
168 buf[508] = (char) minor_root;
169 buf[509] = (char) major_root;
170 i=write(1,buf,512);
171 if (i!=512)
172 die("Write call failed");
173 close (id);
174
175 if ((id=open(argv[2],O_RDONLY,0))<0)
176 die("Unable to open 'setup'");
177 if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
178 die("Unable to read header of 'setup'");
179 if (((long *) buf)[0]!=intel_long(0x04100301))
180 die("Non-Minix header of 'setup'");
181 if (((long *) buf)[1]!=intel_long(MINIX_HEADER))
182 die("Non-Minix header of 'setup'");
183 if (((long *) buf)[3] != 0)
184 die("Illegal data segment in 'setup'");
185 if (((long *) buf)[4] != 0)
186 die("Illegal bss in 'setup'");
187 if (((long *) buf)[5] != 0)
188 die("Non-Minix header of 'setup'");
189 if (((long *) buf)[7] != 0)
190 die("Illegal symbol table in 'setup'");
191 for (i=0 ; (c=read(id,buf,sizeof buf))>0 ; i+=c )
192 #ifdef __BIG_KERNEL__
193 {
194 if (!i) {
195 /* Working with memcpy because of alignment constraints
196 on Sparc - Gertjan */
197 memcpy(&tmp_long, &buf[2], sizeof(long));
198 if (tmp_long != intel_long(0x53726448) )
199 die("Wrong magic in loader header of 'setup'");
200 memcpy(&tmp_int, &buf[6], sizeof(int));
201 if (tmp_int < intel_int(0x200))
202 die("Wrong version of loader header of 'setup'");
203 buf[0x11] = 1; /* LOADED_HIGH */
204 tmp_long = intel_long(0x100000);
205 memcpy(&buf[0x14], &tmp_long, sizeof(long)); /* code32_start */
206 }
207 #endif
208 if (write(1,buf,c)!=c)
209 die("Write call failed");
210 #ifdef __BIG_KERNEL__
211 }
212 #endif
213 if (c != 0)
214 die("read-error on 'setup'");
215 close (id);
216 setup_sectors = (unsigned char)((i + 511) / 512);
217 /* for compatibility with LILO */
218 if (setup_sectors < SETUP_SECTS)
219 setup_sectors = SETUP_SECTS;
220 fprintf(stderr,"Setup is %d bytes.\n",i);
221 for (c=0 ; c<sizeof(buf) ; c++)
222 buf[c] = '\0';
223 while (i < setup_sectors * 512) {
224 c = setup_sectors * 512 - i;
225 if (c > sizeof(buf))
226 c = sizeof(buf);
227 if (write(1,buf,c) != c)
228 die("Write call failed");
229 i += c;
230 }
231
232 if ((id=open(argv[3],O_RDONLY,0))<0)
233 die("Unable to open 'system'");
234 #ifndef __BFD__
235 if (read(id,buf,GCC_HEADER) != GCC_HEADER)
236 die("Unable to read header of 'system'");
237 if (N_MAGIC(*ex) == ZMAGIC) {
238 GCC_HEADER = N_MAGIC_OFFSET;
239 lseek(id, GCC_HEADER, SEEK_SET);
240 } else if (N_MAGIC(*ex) != QMAGIC)
241 die("Non-GCC header of 'system'");
242 fprintf(stderr,"System is %d kB (%d kB code, %d kB data and %d kB bss)\n",
243 (ex->a_text+ex->a_data+ex->a_bss)/1024,
244 ex->a_text /1024,
245 ex->a_data /1024,
246 ex->a_bss /1024);
247 sz = N_SYMOFF(*ex) - GCC_HEADER + 4;
248 #else
249 if (fstat (id, &sb)) {
250 perror ("fstat");
251 die ("Unable to stat 'system'");
252 }
253 sz = sb.st_size;
254 fprintf (stderr, "System is %d kB\n", sz/1024);
255 #endif
256 sys_size = (sz + 15) / 16;
257 if (sys_size > SYS_SIZE)
258 die("System is too big");
259 while (sz > 0) {
260 int l, n;
261
262 l = sz;
263 if (l > sizeof(buf))
264 l = sizeof(buf);
265 if ((n=read(id, buf, l)) != l) {
266 if (n == -1)
267 perror(argv[1]);
268 else
269 fprintf(stderr, "Unexpected EOF\n");
270 die("Can't read 'system'");
271 }
272 if (write(1, buf, l) != l)
273 die("Write failed");
274 sz -= l;
275 }
276 close(id);
277 if (lseek(1, 497, 0) == 497) {
278 if (write(1, &setup_sectors, 1) != 1)
279 die("Write of setup sectors failed");
280 }
281 if (lseek(1,500,0) == 500) {
282 buf[0] = (sys_size & 0xff);
283 buf[1] = ((sys_size >> 8) & 0xff);
284 if (write(1, buf, 2) != 2)
285 die("Write failed");
286 }
287 return(0);
288 }
289