1 #include <sys/types.h>
2 #include <sys/fcntl.h>
3 #include <sys/mman.h>
4 #include <unistd.h>
5
main(int argc,char ** argv)6 int main(int argc, char** argv)
7 {
8 int fd, fd2;
9 caddr_t addr;
10 char zeros[4096];
11 char ones[200];
12
13 memset(zeros, 0, sizeof zeros);
14 memset(ones, 1, sizeof ones);
15 #if 0
16 unlink("test2.data");
17 fd = open("test2.data", O_RDWR|O_CREAT, 0666);
18 if (fd < 0)
19 err(1, "creating file");
20 if (write(fd, zeros, sizeof zeros) < 0)
21 err(1, "writing zeros");
22 close(fd);
23 #endif
24
25 fd = open("test2.data", O_RDWR);
26 if (fd < 0)
27 err(1, "opening file");
28 if (lseek(fd, 600, SEEK_SET) < 0)
29 err(1, "seeking");
30
31 if (write(fd, ones, sizeof ones) < 0)
32 err(1, "writing ones");
33
34 addr = mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
35 if (addr == MAP_FAILED)
36 err(1, "mapping");
37 unlink("test2.scratch");
38 fd2 = open("test2.scratch", O_RDWR|O_CREAT, 0666);
39 if (fd2 < 0)
40 err(1, "creating scratch");
41
42 if (write(fd2, addr, 4096) < 0)
43 err(1, "writing scratch");
44 }
45