45 lines
1012 B
C
45 lines
1012 B
C
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#include <sys/types.h>
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#include <sys/fcntl.h>
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#include <sys/mman.h>
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#include <unistd.h>
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int main(int argc, char** argv)
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{
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int fd, fd2;
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caddr_t addr;
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char zeros[4096];
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char ones[200];
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memset(zeros, 0, sizeof zeros);
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memset(ones, 1, sizeof ones);
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#if 0
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unlink("test2.data");
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fd = open("test2.data", O_RDWR|O_CREAT, 0666);
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if (fd < 0)
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err(1, "creating file");
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if (write(fd, zeros, sizeof zeros) < 0)
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err(1, "writing zeros");
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close(fd);
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#endif
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fd = open("test2.data", O_RDWR);
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if (fd < 0)
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err(1, "opening file");
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if (lseek(fd, 600, SEEK_SET) < 0)
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err(1, "seeking");
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if (write(fd, ones, sizeof ones) < 0)
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err(1, "writing ones");
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addr = mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
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if (addr == MAP_FAILED)
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err(1, "mapping");
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unlink("test2.scratch");
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fd2 = open("test2.scratch", O_RDWR|O_CREAT, 0666);
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if (fd2 < 0)
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err(1, "creating scratch");
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if (write(fd2, addr, 4096) < 0)
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err(1, "writing scratch");
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}
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