]>
Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
b920de1b DH |
2 | /* |
3 | * Copyright (C) 1991, 1992 Linus Torvalds | |
4 | * Copyright (C) 1997 Martin Mares | |
5 | */ | |
6 | ||
7 | /* | |
8 | * This file builds a disk-image from three different files: | |
9 | * | |
10 | * - bootsect: exactly 512 bytes of 8086 machine code, loads the rest | |
11 | * - setup: 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 | * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996 | |
22 | * Cross compiling fixes by Gertjan van Wingerde, July 1996 | |
23 | * Rewritten by Martin Mares, April 1997 | |
24 | */ | |
25 | ||
26 | #include <stdio.h> | |
27 | #include <string.h> | |
28 | #include <stdlib.h> | |
29 | #include <stdarg.h> | |
30 | #include <sys/types.h> | |
31 | #include <sys/stat.h> | |
32 | #include <sys/sysmacros.h> | |
33 | #include <unistd.h> | |
34 | #include <fcntl.h> | |
35 | #include <asm/boot.h> | |
36 | ||
37 | #define DEFAULT_MAJOR_ROOT 0 | |
38 | #define DEFAULT_MINOR_ROOT 0 | |
39 | ||
40 | /* Minimal number of setup sectors (see also bootsect.S) */ | |
41 | #define SETUP_SECTS 4 | |
42 | ||
43 | uint8_t buf[1024]; | |
44 | int fd; | |
45 | int is_big_kernel; | |
46 | ||
47 | __attribute__((noreturn)) | |
48 | void die(const char *str, ...) | |
49 | { | |
50 | va_list args; | |
51 | va_start(args, str); | |
52 | vfprintf(stderr, str, args); | |
53 | fputc('\n', stderr); | |
54 | exit(1); | |
55 | } | |
56 | ||
57 | void file_open(const char *name) | |
58 | { | |
59 | fd = open(name, O_RDONLY, 0); | |
60 | if (fd < 0) | |
61 | die("Unable to open `%s': %m", name); | |
62 | } | |
63 | ||
64 | __attribute__((noreturn)) | |
65 | void usage(void) | |
66 | { | |
67 | die("Usage: build [-b] bootsect setup system [rootdev] [> image]"); | |
68 | } | |
69 | ||
70 | int main(int argc, char **argv) | |
71 | { | |
72 | unsigned int i, c, sz, setup_sectors; | |
73 | uint32_t sys_size; | |
74 | uint8_t major_root, minor_root; | |
75 | struct stat sb; | |
76 | ||
77 | if (argc > 2 && !strcmp(argv[1], "-b")) { | |
78 | is_big_kernel = 1; | |
79 | argc--, argv++; | |
80 | } | |
81 | if ((argc < 4) || (argc > 5)) | |
82 | usage(); | |
83 | if (argc > 4) { | |
84 | if (!strcmp(argv[4], "CURRENT")) { | |
85 | if (stat("/", &sb)) { | |
86 | perror("/"); | |
87 | die("Couldn't stat /"); | |
88 | } | |
89 | major_root = major(sb.st_dev); | |
90 | minor_root = minor(sb.st_dev); | |
91 | } else if (strcmp(argv[4], "FLOPPY")) { | |
92 | if (stat(argv[4], &sb)) { | |
93 | perror(argv[4]); | |
94 | die("Couldn't stat root device."); | |
95 | } | |
96 | major_root = major(sb.st_rdev); | |
97 | minor_root = minor(sb.st_rdev); | |
98 | } else { | |
99 | major_root = 0; | |
100 | minor_root = 0; | |
101 | } | |
102 | } else { | |
103 | major_root = DEFAULT_MAJOR_ROOT; | |
104 | minor_root = DEFAULT_MINOR_ROOT; | |
105 | } | |
106 | fprintf(stderr, "Root device is (%d, %d)\n", major_root, minor_root); | |
107 | ||
108 | file_open(argv[1]); | |
109 | i = read(fd, buf, sizeof(buf)); | |
110 | fprintf(stderr, "Boot sector %d bytes.\n", i); | |
111 | if (i != 512) | |
112 | die("Boot block must be exactly 512 bytes"); | |
113 | if (buf[510] != 0x55 || buf[511] != 0xaa) | |
114 | die("Boot block hasn't got boot flag (0xAA55)"); | |
115 | buf[508] = minor_root; | |
116 | buf[509] = major_root; | |
117 | if (write(1, buf, 512) != 512) | |
118 | die("Write call failed"); | |
119 | close(fd); | |
120 | ||
121 | /* Copy the setup code */ | |
122 | file_open(argv[2]); | |
123 | for (i = 0; (c = read(fd, buf, sizeof(buf))) > 0; i += c) | |
124 | if (write(1, buf, c) != c) | |
125 | die("Write call failed"); | |
126 | if (c != 0) | |
127 | die("read-error on `setup'"); | |
128 | close(fd); | |
129 | ||
130 | /* Pad unused space with zeros */ | |
131 | setup_sectors = (i + 511) / 512; | |
132 | /* for compatibility with ancient versions of LILO. */ | |
133 | if (setup_sectors < SETUP_SECTS) | |
134 | setup_sectors = SETUP_SECTS; | |
135 | fprintf(stderr, "Setup is %d bytes.\n", i); | |
136 | memset(buf, 0, sizeof(buf)); | |
137 | while (i < setup_sectors * 512) { | |
138 | c = setup_sectors * 512 - i; | |
139 | if (c > sizeof(buf)) | |
140 | c = sizeof(buf); | |
141 | if (write(1, buf, c) != c) | |
142 | die("Write call failed"); | |
143 | i += c; | |
144 | } | |
145 | ||
146 | file_open(argv[3]); | |
147 | if (fstat(fd, &sb)) | |
148 | die("Unable to stat `%s': %m", argv[3]); | |
149 | sz = sb.st_size; | |
150 | fprintf(stderr, "System is %d kB\n", sz / 1024); | |
151 | sys_size = (sz + 15) / 16; | |
152 | /* 0x28000*16 = 2.5 MB, conservative estimate for the current maximum */ | |
153 | if (sys_size > (is_big_kernel ? 0x28000 : DEF_SYSSIZE)) | |
154 | die("System is too big. Try using %smodules.", | |
155 | is_big_kernel ? "" : "bzImage or "); | |
156 | if (sys_size > 0xffff) | |
157 | fprintf(stderr, | |
158 | "warning: kernel is too big for standalone boot " | |
159 | "from floppy\n"); | |
160 | while (sz > 0) { | |
161 | int l, n; | |
162 | ||
163 | l = (sz > sizeof(buf)) ? sizeof(buf) : sz; | |
164 | n = read(fd, buf, l); | |
165 | if (n != l) { | |
166 | if (n < 0) | |
167 | die("Error reading %s: %m", argv[3]); | |
168 | else | |
169 | die("%s: Unexpected EOF", argv[3]); | |
170 | } | |
171 | if (write(1, buf, l) != l) | |
172 | die("Write failed"); | |
173 | sz -= l; | |
174 | } | |
175 | close(fd); | |
176 | ||
177 | /* Write sizes to the bootsector */ | |
178 | if (lseek(1, 497, SEEK_SET) != 497) | |
179 | die("Output: seek failed"); | |
180 | buf[0] = setup_sectors; | |
181 | if (write(1, buf, 1) != 1) | |
182 | die("Write of setup sector count failed"); | |
183 | if (lseek(1, 500, SEEK_SET) != 500) | |
184 | die("Output: seek failed"); | |
185 | buf[0] = (sys_size & 0xff); | |
186 | buf[1] = ((sys_size >> 8) & 0xff); | |
187 | if (write(1, buf, 2) != 2) | |
188 | die("Write of image length failed"); | |
189 | ||
190 | return 0; | |
191 | } |