#include <fcntl.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <string.h>

#include <linux/types.h>
#include <stdio.h>
#include <errno.h>

#ifndef FS_IOC_SETFLAGS
#define FS_IOC_SETFLAGS                 _IOW('f', 2, long)
#warning defining SETFLAGS locally
#endif

#ifndef FS_IOC_GETFLAGS
#define FS_IOC_GETFLAGS                 _IOR('f', 1, long)
#warning defining GETFLAGS locally
#endif

#ifndef FS_NOCOW_FL
#define FS_NOCOW_FL                     0x00800000 /* Do not cow file */
#endif

int main(int argc, char **argv)
{
        int fd;
        int r;
  long flags;

  if (argc < 2) {
    printf("usage: %s file\n", argv[0]);
    exit(1);
  }

  fd = open(argv[1], O_RDONLY);
  if (fd == -1) {
    perror("open()");
    return 1;
  }
  printf("GETFLAGS ioctl 0x%x\n", FS_IOC_GETFLAGS);
  printf("SETFLAGS ioctl 0x%x\n", FS_IOC_SETFLAGS);

  r = ioctl(fd, FS_IOC_GETFLAGS, &flags);
  if (r == -1) {
    perror("ioctl(GETFLAGS)");
    return 1;
  } else {
    printf("file flags before: 0x%lx\n", flags);
  }

  if(strcmp(argv[0], "cow")==0) {
    printf("Remove NOCOW flag for %s\n", argv[1]);
    flags ^= FS_NOCOW_FL;
  } else {
    printf("Set NOCOW flag for %s\n", argv[1]);    
    flags |= FS_NOCOW_FL;
  }
  r = ioctl(fd, FS_IOC_SETFLAGS, &flags);
  printf("ioctl returned: %d\n", r);
  if (r == -1) {
    perror("ioctl()");
    return 1;
  }

  r = ioctl(fd, FS_IOC_GETFLAGS, &flags);
  if (r == -1) {
    perror("ioctl(GETFLAGS)");
    return 1;
  } else {
    printf("file flags after:  0x%lx\n", flags);
  }  

  return 0;
}