134 lines
2.6 KiB
C
134 lines
2.6 KiB
C
/*
|
|
* open-cd-excl.c --- This program tries to open a block device
|
|
* by various exclusive and non-exclusive gestures in order to explore
|
|
* their impact on running CD/DVD recordings.
|
|
*
|
|
* Copyright 2007, by Theodore Ts'o.
|
|
*
|
|
* Detail modifications 2007, by Thomas Schmitt.
|
|
*
|
|
* %Begin-Header%
|
|
* This file may be redistributed under the terms of the GNU Public
|
|
* License.
|
|
* %End-Header%
|
|
*/
|
|
|
|
#define _GNU_SOURCE /* for O_LARGEFILE *//*ts A70417: or _LARGEFILE64_SOURCE */
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <stdlib.h>
|
|
#include <fcntl.h>
|
|
#include <getopt.h>
|
|
|
|
const char *progname;
|
|
|
|
static void usage(void)
|
|
{
|
|
fprintf(stderr, "Usage: %s [-feirw] device\n", progname);
|
|
exit(1);
|
|
}
|
|
|
|
/* ts A70417: added parameter do_rdwr */
|
|
static void init_flock(struct flock *fl, int do_rdwr)
|
|
{
|
|
memset(fl, 0, sizeof(struct flock));
|
|
if (do_rdwr)
|
|
fl->l_type = F_WRLCK;
|
|
else
|
|
fl->l_type = F_RDLCK;
|
|
fl->l_whence = SEEK_SET;
|
|
fl->l_start = 0;
|
|
fl->l_len = 0;
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
struct flock fl;
|
|
char *device_name;
|
|
int fd, c, f_opt = 0, do_rdwr = 0, end_immediately = 0;
|
|
int flags = O_NONBLOCK|O_LARGEFILE;
|
|
|
|
progname = argv[0];
|
|
|
|
/* ts A70417: added -w , -r , -i */
|
|
while ((c = getopt (argc, argv, "feirw")) != EOF) {
|
|
switch (c) {
|
|
case 'e':
|
|
flags |= O_EXCL;
|
|
break;
|
|
case 'f':
|
|
f_opt++;
|
|
break;
|
|
case 'i':
|
|
end_immediately = 1;
|
|
break;
|
|
case 'r':
|
|
do_rdwr = 0;
|
|
break;
|
|
case 'w':
|
|
do_rdwr = 1;
|
|
break;
|
|
case '?':
|
|
usage();
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
if (optind == argc)
|
|
usage();
|
|
device_name = argv[optind++];
|
|
|
|
/* ts A70417 : made read-write adjustable independently of f_opt */
|
|
if (do_rdwr) {
|
|
flags |= O_RDWR;
|
|
printf("Using O_RDWR\n");
|
|
} else {
|
|
flags |= O_RDONLY;
|
|
printf("Using O_RDONLY\n");
|
|
}
|
|
|
|
if (flags & O_EXCL)
|
|
printf("Trying to open %s with O_EXCL ...\n", device_name);
|
|
fd = open(device_name, flags, 0);
|
|
if (fd < 0) {
|
|
perror("open");
|
|
printf("failed\n");
|
|
exit(1);
|
|
}
|
|
if (flags & O_EXCL)
|
|
printf("succeeded\n");
|
|
|
|
if (f_opt) {
|
|
init_flock(&fl, do_rdwr);
|
|
if (fcntl(fd, F_GETLK, &fl) < 0) {
|
|
perror("fcntl: F_GETLK: ");
|
|
exit(1);
|
|
}
|
|
printf("fcntl lock apparently %sLOCKED\n",
|
|
(fl.l_type == F_UNLCK) ? "NOT " : "");
|
|
|
|
init_flock(&fl, do_rdwr);
|
|
printf("Trying to grab fcntl lock...\n");
|
|
if (fcntl(fd, F_SETLK, &fl) < 0) {
|
|
perror("fcntl: F_SETLK: ");
|
|
printf("failed\n");
|
|
exit(1);
|
|
}
|
|
printf("succeeded\n");
|
|
}
|
|
|
|
/* ts A70417: added end_immediately */
|
|
printf("Holding %s open.\n", device_name);
|
|
usleep(100000);
|
|
if (end_immediately)
|
|
exit(0);
|
|
printf("Press ^C to exit.\n");
|
|
while (1) {
|
|
sleep(300);
|
|
}
|
|
/* NOTREACHED */
|
|
return 0;
|
|
}
|