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/*
* The Original Code is legOS code, released October 2, 1999.
*
* The Initial Developer of the Original Code is Markus L. Noga.
* Portions created by Markus L. Noga are Copyright (C) 1999
* Markus L. Noga. All Rights Reserved.
*
* Contributor(s): Kekoa Proudfoot <kekoa@graphics.stanford.edu>
*/
#include <stdlib.h>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>
#ifdef __linux__
#include <linux/serial.h>
#endif
#include <sys/ioctl.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include "logger.h"
#include "lnp.h"
#include "rcxtty.h"
static int fd;
static char *lockfilename;
// try to create lockfile
// returns -1 on failure, 0 on success
static int make_lockfile(const char *device)
{
char lockname[FILENAME_MAX];
int nchars,result,lockfd,lockpid;
FILE* lockfp;
char filepid[16];
// create lockfile name
if ( strchr( device, '/' ) != NULL )
device = strrchr( device, '/' ) +1;
nchars = snprintf( lockname, FILENAME_MAX, "%s/%s%s" , LOCKDIR, LOCKNAME, device);
// should work with glibc2.0 and 2.1
if (nchars < 0 || nchars >= FILENAME_MAX)
{
log(LNPD_LOG_INFO,"tty name too long");
return -1;
}
// create lockfile
while ( ( lockfd = open(lockname, O_WRONLY | O_CREAT | O_EXCL, 0644) ) < 0 )
{
if (errno != EEXIST )
{
log(LNPD_LOG_INFO,"cannot create lockfile: %s", strerror(errno));
return -1;
}
else // lock file already there
{
// read pid from Lockfile
if ( ( lockfp = fopen(lockname, "r" )) == NULL )
{
if ( errno == ENOENT ) continue; // lock file disappeared
else
{
log(LNPD_LOG_INFO,"cannot open lockfile %s",lockname);
return -1;
}
}
result = fscanf(lockfp, "%d", &lockpid);
fclose( lockfp );
if (result != 1)
{
log(LNPD_LOG_INFO,"cannot read pid from lockfile %s",lockname);
return -1;
}
// check if process already dead or its our own pid
result = kill(lockpid, 0);
if ( (result < 0 && errno == ESRCH) || ( lockpid == (int)getpid() ) )
{
// process is gone, try to remove stale lock
log( LNPD_LOG_INFO, "trying to unlink stale lockfile");
if ( unlink(lockname) < 0 &&
errno != EINTR && errno != ENOENT )
{
log( LNPD_LOG_INFO, "cannot unlink stale lockfile: %s",strerror(errno));
return -1;
}
continue;
}
log(LNPD_LOG_INFO, "device is locked by pid %d ",lockpid);
return -1;
}
}
lockfilename = strdup(lockname);
// write pid to lockfile
sprintf( filepid, "%10d\n", (int) getpid() );
if ( write(lockfd, filepid, strlen(filepid)) != strlen(filepid) )
{
log(LNPD_LOG_INFO,"cannot write to lockfile %s",strerror(errno));
close(lockfd);
return -1;
}
close(lockfd);
log(LNPD_LOG_INFO, "created lock file %s",lockname);
return 0;
}
void tty_exit(void)
{
if (lockfilename) unlink(lockfilename);
}
// initialize RCX communications port
int tty_init(int highspeed,int nolock,const char *device)
{
struct termios ios;
#ifdef __linux__
struct serial_struct ttyinfo;
#endif
// try to create lockfile
if ( !nolock && make_lockfile(device))
{
log(LNPD_LOG_FATAL,"cannot create lockfile");
exit(1);
}
// open the device
if ( (fd = open(device, O_RDWR )) < 0)
error_exit("open");
// check if its a tty
if (!isatty(fd))
{
log(LNPD_LOG_FATAL, "%s is not a tty", device);
exit(1);
}
// set to noncanonical mode, implies nonblocking behaviour
memset(&ios, 0, sizeof(ios));
ios.c_cflag = CREAD | CLOCAL | CS8 | (highspeed ? 0 : PARENB | PARODD);
cfsetispeed(&ios, highspeed ? LNP_BAUD_FAST : LNP_BAUD_SLOW );
cfsetospeed(&ios, highspeed ? LNP_BAUD_FAST : LNP_BAUD_SLOW );
if (tcsetattr(fd, TCSANOW, &ios) == -1)
error_exit("tcsetattr");
#ifdef __linux__
// try to set to "hard realtime mode"
if (ioctl(fd,TIOCGSERIAL,&ttyinfo))
error_exit("ioctl[TIOCGSERIAL]");
switch (ttyinfo.type)
{
case PORT_16550A:
ttyinfo.type = PORT_16450;
ttyinfo.flags |= ASYNC_LOW_LATENCY;
break;
case PORT_16450:
case PORT_8250:
case PORT_16550:
ttyinfo.flags |= ASYNC_LOW_LATENCY;
break;
default:
log(LNPD_LOG_INFO,"dont know how to configure tty, trying low_latency");
ttyinfo.flags |= ASYNC_LOW_LATENCY;
}
if (ioctl(fd,TIOCSSERIAL,&ttyinfo))
{
log(LNPD_LOG_INFO,"failed to configure tty: %s",strerror(errno));
}
#endif
// we must close and reopen the tty
close(fd);
if ( (fd = open(device, O_RDWR )) < 0)
error_exit("open");
return fd;
}
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