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/*
* Knock-Knock Token
* by zx2c4
* Jason@zx2c4.com
*
* Someone about to steal your laptop and you have sensitive things open on it?
* With Knock-Knock Token, you specify a block device that belongs to removable
* storage such as a USB flash drive. When the flash drive is removed from the
* USB port, and the block device disappears as a consequence, your computer
* immediately turns off. So, as the thief is snatching your laptop from you,
* simply snatch the USB key, and your data is saved. The program automatically
* daemonizes.
*
* $ sudo ./knock-knock-token /dev/sdc1
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/inotify.h>
#include <sys/reboot.h>
int main(int argc, char *argv[])
{
int inotify, device_monitor;
struct stat file_info;
if (argc < 2) {
fprintf(stderr, "Usage: %s BLOCK_DEVICE\n", argv[0]);
return EXIT_FAILURE;
}
if (getuid()) {
fprintf(stderr, "You must be root to run this program.\n");
return EXIT_FAILURE;
}
if (stat(argv[1], &file_info) < 0) {
perror("stat");
return EXIT_FAILURE;
}
if (!S_ISBLK(file_info.st_mode))
fprintf(stderr, "Warning: %s is not a block device. Are you sure you meant to monitor it?\n", argv[1]);
inotify = inotify_init();
if (inotify < 0) {
perror("inotify_init");
return EXIT_FAILURE;
}
device_monitor = inotify_add_watch(inotify, argv[1], IN_DELETE_SELF);
if (device_monitor < 0) {
perror("inotify_add_watch");
return EXIT_FAILURE;
}
fprintf(stderr, "Daemonizing...\n");
if (daemon(0, 0) < 0)
perror("daemon");
device_monitor = read(inotify, NULL, 0);
//TODO: securely wipe memory
sync();
reboot(RB_ENABLE_CAD);
reboot(RB_POWER_OFF);
reboot(RB_HALT_SYSTEM);
return EXIT_SUCCESS;
}
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