This source file includes following definitions.
- main
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13 #include <fcntl.h>
14 #include <unistd.h>
15 #include <stdlib.h>
16 #include <stdio.h>
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20
21 #ifndef MAXPARTITIONS
22 #define MAXPARTITIONS 8
23 #endif
24
25 #ifndef u8
26 #define u8 unsigned char
27 #endif
28
29 #ifndef u16
30 #define u16 unsigned short
31 #endif
32
33 #ifndef u32
34 #define u32 unsigned int
35 #endif
36
37 struct disklabel {
38 u32 d_magic;
39 u16 d_type, d_subtype;
40 u8 d_typename[16];
41 u8 d_packname[16];
42 u32 d_secsize;
43 u32 d_nsectors;
44 u32 d_ntracks;
45 u32 d_ncylinders;
46 u32 d_secpercyl;
47 u32 d_secprtunit;
48 u16 d_sparespertrack;
49 u16 d_sparespercyl;
50 u32 d_acylinders;
51 u16 d_rpm, d_interleave, d_trackskew, d_cylskew;
52 u32 d_headswitch, d_trkseek, d_flags;
53 u32 d_drivedata[5];
54 u32 d_spare[5];
55 u32 d_magic2;
56 u16 d_checksum;
57 u16 d_npartitions;
58 u32 d_bbsize, d_sbsize;
59 struct d_partition {
60 u32 p_size;
61 u32 p_offset;
62 u32 p_fsize;
63 u8 p_fstype;
64 u8 p_frag;
65 u16 p_cpg;
66 } d_partitions[MAXPARTITIONS];
67 };
68
69
70 typedef union __bootblock {
71 struct {
72 char __pad1[64];
73 struct disklabel __label;
74 } __u1;
75 struct {
76 unsigned long __pad2[63];
77 unsigned long __checksum;
78 } __u2;
79 char bootblock_bytes[512];
80 unsigned long bootblock_quadwords[64];
81 } bootblock;
82
83 #define bootblock_label __u1.__label
84 #define bootblock_checksum __u2.__checksum
85
86 int main(int argc, char ** argv)
87 {
88 bootblock bootblock_from_disk;
89 bootblock bootloader_image;
90 int dev, fd;
91 int i;
92 int nread;
93
94
95 if(argc != 3) {
96 fprintf(stderr, "Usage: %s device lxboot\n", argv[0]);
97 exit(0);
98 }
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101 dev = open(argv[1], O_RDWR);
102 if(dev < 0) {
103 perror(argv[1]);
104 exit(0);
105 }
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108 fd = open(argv[2], O_RDONLY);
109 if(fd < 0) {
110 perror(argv[2]);
111 close(dev);
112 exit(0);
113 }
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116 nread = read(fd, &bootloader_image, sizeof(bootblock));
117 if(nread != sizeof(bootblock)) {
118 perror("lxboot read");
119 fprintf(stderr, "expected %zd, got %d\n", sizeof(bootblock), nread);
120 exit(0);
121 }
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124 nread = read(dev, &bootblock_from_disk, sizeof(bootblock));
125 if(nread != sizeof(bootblock)) {
126 perror("bootblock read");
127 fprintf(stderr, "expected %zd, got %d\n", sizeof(bootblock), nread);
128 exit(0);
129 }
130
131
132 bootloader_image.bootblock_label = bootblock_from_disk.bootblock_label;
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134
135 bootloader_image.bootblock_checksum = 0;
136 for(i = 0; i < 63; i++) {
137 bootloader_image.bootblock_checksum +=
138 bootloader_image.bootblock_quadwords[i];
139 }
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141
142 lseek(dev, 0L, SEEK_SET);
143 if(write(dev, &bootloader_image, sizeof(bootblock)) != sizeof(bootblock)) {
144 perror("bootblock write");
145 exit(0);
146 }
147
148 close(fd);
149 close(dev);
150 exit(0);
151 }
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