23 lines
576 B
C
23 lines
576 B
C
#include <unistd.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdint.h>
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int main(int argc, char* argv[]) {
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if (argc != 2) {
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fprintf(stderr, "Usage: %s mbr.bin\n", argv[0]);
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return 1;
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}
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const char* filename = argv[1];
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int fd = open(filename, O_RDWR);
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off_t length = lseek(fd, 0, SEEK_END);
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if (length > 510) {
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fprintf(stderr, "file %s is larger than 510 bytes (size: %ju)\n",
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filename, (uintmax_t)length);
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return 1;
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}
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lseek(fd, 510, SEEK_SET);
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write(fd, "\x55\xaa", 2);
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return 0;
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}
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