|
|
|
@ -144,7 +144,47 @@ void tearDownPipe()
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
void setupPipe()
|
|
|
|
|
bool setFileLock(int fd, bool close_on_failure)
|
|
|
|
|
{
|
|
|
|
|
struct flock fl;
|
|
|
|
|
|
|
|
|
|
fl.l_type = F_WRLCK;
|
|
|
|
|
fl.l_whence = SEEK_SET;
|
|
|
|
|
fl.l_start = 0;
|
|
|
|
|
fl.l_len = 1;
|
|
|
|
|
|
|
|
|
|
// Set the exclusive file lock
|
|
|
|
|
if (fcntl(mPipe_fd_out, F_SETLK, &fl) == -1) {
|
|
|
|
|
close(mPipe_fd_out);
|
|
|
|
|
return false;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return true;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
bool checkFileLock()
|
|
|
|
|
{
|
|
|
|
|
struct flock fl;
|
|
|
|
|
|
|
|
|
|
fl.l_type = F_WRLCK; /* Test for any lock on any part of file. */
|
|
|
|
|
fl.l_start = 0;
|
|
|
|
|
fl.l_whence = SEEK_SET;
|
|
|
|
|
fl.l_len = 0;
|
|
|
|
|
|
|
|
|
|
int fd = open(FIFO_FILE_OUT, O_RDWR | O_NONBLOCK);
|
|
|
|
|
fcntl(fd, F_GETLK, &fl); /* Overwrites lock structure with preventors. */
|
|
|
|
|
|
|
|
|
|
if (fd > -1) {
|
|
|
|
|
if (fl.l_type == F_WRLCK) {
|
|
|
|
|
return false;
|
|
|
|
|
}
|
|
|
|
|
return true;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return true;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
bool setupPipe()
|
|
|
|
|
{
|
|
|
|
|
/* Create the FIFOs if they do not exist */
|
|
|
|
|
umask(0);
|
|
|
|
@ -153,30 +193,13 @@ void setupPipe()
|
|
|
|
|
mknod(FIFO_FILE_OUT, S_IFIFO|0600, 0);
|
|
|
|
|
chmod(FIFO_FILE_OUT, 0600);
|
|
|
|
|
|
|
|
|
|
mPipe_fd_out = open(FIFO_FILE_OUT, O_WRONLY | O_NONBLOCK);
|
|
|
|
|
mPipe_fd_out = open(FIFO_FILE_OUT, O_RDWR | O_NONBLOCK);
|
|
|
|
|
if (mPipe_fd_out > -1) {
|
|
|
|
|
mPipeOpen_out = true;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
bool checkLocks()
|
|
|
|
|
{
|
|
|
|
|
int fdlock;
|
|
|
|
|
struct flock fl;
|
|
|
|
|
|
|
|
|
|
fl.l_type = F_WRLCK;
|
|
|
|
|
fl.l_whence = SEEK_SET;
|
|
|
|
|
fl.l_start = 0;
|
|
|
|
|
fl.l_len = 1;
|
|
|
|
|
|
|
|
|
|
fdlock = open(FIFO_FILE_OUT, O_RDWR | O_NONBLOCK);
|
|
|
|
|
if (fdlock != -1) {
|
|
|
|
|
if(fcntl(fdlock, F_SETLK, &fl) == -1) {
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return 1;
|
|
|
|
|
// Set the exclusive file lock
|
|
|
|
|
return setFileLock(mPipe_fd_out, true);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
class PipeHandler
|
|
|
|
@ -214,13 +237,18 @@ int main (int argc, char *argv[])
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (!checkLocks()) {
|
|
|
|
|
// Check for existing file locks
|
|
|
|
|
if (!checkFileLock()) {
|
|
|
|
|
fprintf(stderr, "Another instance of this program is already running\n");
|
|
|
|
|
return 8;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Create the output pipe
|
|
|
|
|
PipeHandler controlpipe;
|
|
|
|
|
if (!setupPipe()) {
|
|
|
|
|
fprintf(stderr, "Another instance of this program is already running\n");
|
|
|
|
|
return 8;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
while (1) {
|
|
|
|
|
if ((getuid ()) != 0) {
|
|
|
|
@ -283,6 +311,14 @@ int main (int argc, char *argv[])
|
|
|
|
|
fprintf(stderr,"Device created.\n");
|
|
|
|
|
|
|
|
|
|
if (established == false) {
|
|
|
|
|
tearDownPipe();
|
|
|
|
|
int i=fork();
|
|
|
|
|
if (i<0) return 9; // fork failed
|
|
|
|
|
if (i>0) {
|
|
|
|
|
// close parent process
|
|
|
|
|
close(mPipe_fd_out);
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
setupPipe();
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|