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/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <termios.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <time.h>
#include <assert.h>
#include <poll.h>
#include <linux/vt.h>
#include <linux/tiocl.h>
#include <linux/kd.h>
#include "terminal-util.h"
#include "time-util.h"
#include "process-util.h"
#include "util.h"
#include "fileio.h"
#include "path-util.h"
static volatile unsigned cached_columns = 0;
static volatile unsigned cached_lines = 0;
int open_terminal(const char *name, int mode) {
int fd, r;
unsigned c = 0;
/*
* If a TTY is in the process of being closed opening it might
* cause EIO. This is horribly awful, but unlikely to be
* changed in the kernel. Hence we work around this problem by
* retrying a couple of times.
*
* https://bugs.launchpad.net/ubuntu/+source/linux/+bug/554172/comments/245
*/
assert(!(mode & O_CREAT));
for (;;) {
fd = open(name, mode, 0);
if (fd >= 0)
break;
if (errno != EIO)
return -errno;
/* Max 1s in total */
if (c >= 20)
return -errno;
usleep(50 * USEC_PER_MSEC);
c++;
}
r = isatty(fd);
if (r < 0) {
safe_close(fd);
return -errno;
}
if (!r) {
safe_close(fd);
return -ENOTTY;
}
return fd;
}
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