test2.c revision 25889 
1#include <sys/types.h>
2#include <sys/fcntl.h>
3#include <sys/mman.h>
4#include <unistd.h>
5
6int 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