write.c

   1 #include <stdlib.h>
   2 #include <fcntl.h>
   3
   4 #define LEN 0x1000
   5 #define ADDR 0x0
   6
   7 int main()
   8 {
   9         int fdpair[2];
  10         int fd = open("mem.dat", O_WRONLY|O_CREAT|O_TRUNC, 0600);
  11
  12         if (fd == -1) {
  13                 perror("open");
  14                 exit(1);
  15         }
  16
  17         while (pipe(fdpair) == 0) {
  18                 if (fork()) {
  19                         char buf[LEN];
  20                         if (read(fdpair[0], buf, LEN) != LEN) {
  21                                 perror("read");
  22                                 exit(1);
  23                         }
  24                         if (write(fd,buf,LEN) != LEN) {
  25                                 perror("write");
  26                                 exit(1);
  27                         }
  28                         waitpid(-1, NULL, 0);
  29                 } else {
  30                         if (write(fdpair[1],ADDR,LEN) != LEN) {
  31                                 perror("write");
  32                                 exit(1);
  33                         }
  34                         _exit(0);
  35                 }
  36         }
  37
  38         return 0;
  39 }