1 /*
2 * linux/tools/build.c
3 *
4 * (C) 1991 Linus Torvalds
5 */
6
7 /*
8 * This file builds a disk-image from three different files:
9 *
10 * - bootsect: max 510 bytes of 8086 machine code, loads the rest
11 * - setup: max 4 sectors of 8086 machine code, sets up system parm
12 * - system: 80386 code for actual system
13 *
14 * It does some checking that all files are of the correct type, and
15 * just writes the result to stdout, removing headers and padding to
16 * the right amount. It also writes some system data to stderr.
17 */
18
19 /*
20 * Changes by tytso to allow root device specification
21 */
22
23 #include <stdio.h> /* fprintf */
24 #include <string.h>
25 #include <stdlib.h> /* contains exit */
26 #include <sys/types.h> /* unistd.h needs this */
27 #include <sys/stat.h>
28 #include <linux/fs.h>
29 #include <unistd.h> /* contains read/write */
30 #include <fcntl.h>
31
32 #define MINIX_HEADER 32
33 #define GCC_HEADER 1024
34
35 #define SYS_SIZE 0x2000
36
37 #define DEFAULT_MAJOR_ROOT 3
38 #define DEFAULT_MINOR_ROOT 6
39
40 /* max nr of sectors of setup: don't change unless you also change
41 * bootsect etc */
42 #define SETUP_SECTS 4
43
44 #define STRINGIFY(x) #x
45
46 void die(char * str)
47 {
48 fprintf(stderr,"%s\n",str);
49 exit(1);
50 }
51
52 void usage(void)
53 {
54 die("Usage: build bootsect setup system [rootdev] [> image]");
55 }
56
57 int main(int argc, char ** argv)
58 {
59 int i,c,id;
60 char buf[1024];
61 char major_root, minor_root;
62 struct stat sb;
63
64 if ((argc != 4) && (argc != 5))
65 usage();
66 if (argc == 5) {
67 if (strcmp(argv[4], "FLOPPY")) {
68 if (stat(argv[4], &sb)) {
69 perror(argv[4]);
70 die("Couldn't stat root device.");
71 }
72 major_root = MAJOR(sb.st_rdev);
73 minor_root = MINOR(sb.st_rdev);
74 } else {
75 major_root = 0;
76 minor_root = 0;
77 }
78 } else {
79 major_root = DEFAULT_MAJOR_ROOT;
80 minor_root = DEFAULT_MINOR_ROOT;
81 }
82 fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root);
83 if ((major_root != 2) && (major_root != 3) &&
84 (major_root != 0)) {
85 fprintf(stderr, "Illegal root device (major = %d)\n",
86 major_root);
87 die("Bad root device --- major #");
88 }
89 for (i=0;i<sizeof buf; i++) buf[i]=0;
90 if ((id=open(argv[1],O_RDONLY,0))<0)
91 die("Unable to open 'boot'");
92 if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
93 die("Unable to read header of 'boot'");
94 if (((long *) buf)[0]!=0x04100301)
95 die("Non-Minix header of 'boot'");
96 if (((long *) buf)[1]!=MINIX_HEADER)
97 die("Non-Minix header of 'boot'");
98 if (((long *) buf)[3]!=0)
99 die("Illegal data segment in 'boot'");
100 if (((long *) buf)[4]!=0)
101 die("Illegal bss in 'boot'");
102 if (((long *) buf)[5] != 0)
103 die("Non-Minix header of 'boot'");
104 if (((long *) buf)[7] != 0)
105 die("Illegal symbol table in 'boot'");
106 i=read(id,buf,sizeof buf);
107 fprintf(stderr,"Boot sector %d bytes.\n",i);
108 if (i != 512)
109 die("Boot block must be exactly 512 bytes");
110 if ((*(unsigned short *)(buf+510)) != 0xAA55)
111 die("Boot block hasn't got boot flag (0xAA55)");
112 buf[508] = (char) minor_root;
113 buf[509] = (char) major_root;
114 i=write(1,buf,512);
115 if (i!=512)
116 die("Write call failed");
117 close (id);
118
119 if ((id=open(argv[2],O_RDONLY,0))<0)
120 die("Unable to open 'setup'");
121 if (read(id,buf,MINIX_HEADER) != MINIX_HEADER)
122 die("Unable to read header of 'setup'");
123 if (((long *) buf)[0]!=0x04100301)
124 die("Non-Minix header of 'setup'");
125 if (((long *) buf)[1]!=MINIX_HEADER)
126 die("Non-Minix header of 'setup'");
127 if (((long *) buf)[3]!=0)
128 die("Illegal data segment in 'setup'");
129 if (((long *) buf)[4]!=0)
130 die("Illegal bss in 'setup'");
131 if (((long *) buf)[5] != 0)
132 die("Non-Minix header of 'setup'");
133 if (((long *) buf)[7] != 0)
134 die("Illegal symbol table in 'setup'");
135 for (i=0 ; (c=read(id,buf,sizeof buf))>0 ; i+=c )
136 if (write(1,buf,c)!=c)
137 die("Write call failed");
138 close (id);
139 if (i > SETUP_SECTS*512)
140 die("Setup exceeds " STRINGIFY(SETUP_SECTS)
141 " sectors - rewrite build/boot/setup");
142 fprintf(stderr,"Setup is %d bytes.\n",i);
143 for (c=0 ; c<sizeof(buf) ; c++)
144 buf[c] = '\0';
145 while (i<SETUP_SECTS*512) {
146 c = SETUP_SECTS*512-i;
147 if (c > sizeof(buf))
148 c = sizeof(buf);
149 if (write(1,buf,c) != c)
150 die("Write call failed");
151 i += c;
152 }
153
154 if ((id=open(argv[3],O_RDONLY,0))<0)
155 die("Unable to open 'system'");
156 if (read(id,buf,GCC_HEADER) != GCC_HEADER)
157 die("Unable to read header of 'system'");
158 if (((long *) buf)[5] != 0)
159 die("Non-GCC header of 'system'");
160 for (i=0 ; (c=read(id,buf,sizeof buf))>0 ; i+=c )
161 if (write(1,buf,c)!=c)
162 die("Write call failed");
163 close(id);
164 fprintf(stderr,"System is %d bytes.\n",i);
165 if (i > SYS_SIZE*16)
166 die("System is too big");
167 return(0);
168 }
169
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