lib/replace/tests/shared_mmap.c

   1 /* this tests whether we can use a shared writeable mmap on a file -
   2    as needed for the mmap variant of FAST_SHARE_MODES */
   3
   4 #if defined(HAVE_UNISTD_H)
   5 #include <unistd.h>
   6 #endif
   7 #ifdef HAVE_STDLIB_H
   8 #include <stdlib.h>
   9 #endif
  10 #include <sys/mman.h>
  11 #include <sys/types.h>
  12 #include <sys/stat.h>
  13 #include <fcntl.h>
  14
  15 #define DATA "conftest.mmap"
  16
  17 #ifndef MAP_FILE
  18 #define MAP_FILE 0
  19 #endif
  20
  21 int main(void)
  22 {
  23         int *buf;
  24         int i;
  25         int fd = open(DATA,O_RDWR|O_CREAT|O_TRUNC,0666);
  26         int count=7;
  27
  28         if (fd == -1) exit(1);
  29
  30         for (i=0;i<10000;i++) {
  31                 write(fd,&i,sizeof(i));
  32         }
  33
  34         close(fd);
  35
  36         if (fork() == 0) {
  37                 fd = open(DATA,O_RDWR);
  38                 if (fd == -1) exit(1);
  39
  40                 buf = (int *)mmap(NULL, 10000*sizeof(int),
  41                                    (PROT_READ | PROT_WRITE),
  42                                    MAP_FILE | MAP_SHARED,
  43                                    fd, 0);
  44
  45                 while (count-- && buf[9124] != 55732) sleep(1);
  46
  47                 if (count <= 0) exit(1);
  48
  49                 buf[1763] = 7268;
  50                 exit(0);
  51         }
  52
  53         fd = open(DATA,O_RDWR);
  54         if (fd == -1) exit(1);
  55
  56         buf = (int *)mmap(NULL, 10000*sizeof(int),
  57                            (PROT_READ | PROT_WRITE),
  58                            MAP_FILE | MAP_SHARED,
  59                            fd, 0);
  60
  61         if (buf == (int *)-1) exit(1);
  62
  63         buf[9124] = 55732;
  64
  65         while (count-- && buf[1763] != 7268) sleep(1);
  66
  67         unlink(DATA);
  68
  69         if (count > 0) exit(0);
  70         exit(1);
  71 }