[thirdparty/util-linux.git] / lib / pty-session.c

/*
 * This is pseudo-terminal container for child process where parent creates a
 * proxy between the current std{in,out,etrr} and the child's pty. Advantages:
 *
 * - child has no access to parent's terminal (e.g. su --pty)
 * - parent can log all traffic between user and child's terminall (e.g. script(1))
 * - it's possible to start commands on terminal although parent has no terminal
 *
 * This code is in the public domain; do with it what you wish.
 *
 * Written by Karel Zak <kzak@redhat.com> in Jul 2019
 */
#include <stdio.h>
#include <stdlib.h>
#include <pty.h>
#include <poll.h>
#include <sys/signalfd.h>
#include <paths.h>
#include <sys/types.h>
#include <sys/wait.h>

#include "c.h"
#include "all-io.h"
#include "ttyutils.h"
#include "pty-session.h"
#include "monotonic.h"
#include "debug.h"

static UL_DEBUG_DEFINE_MASK(ulpty);
UL_DEBUG_DEFINE_MASKNAMES(ulpty) = UL_DEBUG_EMPTY_MASKNAMES;

#define ULPTY_DEBUG_INIT	(1 << 1)
#define ULPTY_DEBUG_SETUP	(1 << 2)
#define ULPTY_DEBUG_SIG		(1 << 3)
#define ULPTY_DEBUG_IO		(1 << 4)
#define ULPTY_DEBUG_DONE	(1 << 5)
#define ULPTY_DEBUG_ALL		0xFFFF

#define DBG(m, x)       __UL_DBG(ulpty, ULPTY_DEBUG_, m, x)
#define ON_DBG(m, x)    __UL_DBG_CALL(ulpty, ULPTY_DEBUG_, m, x)

#define UL_DEBUG_CURRENT_MASK   UL_DEBUG_MASK(ulpty)
#include "debugobj.h"

void ul_pty_init_debug(int mask)
{
	if (ulpty_debug_mask)
		return;
	__UL_INIT_DEBUG_FROM_ENV(ulpty, ULPTY_DEBUG_, mask, ULPTY_DEBUG);
}

struct ul_pty *ul_new_pty(int is_stdin_tty)
{
	struct ul_pty *pty = calloc(1, sizeof(*pty));

	if (!pty)
		return NULL;

	DBG(SETUP, ul_debugobj(pty, "alloc handler"));
	pty->isterm = is_stdin_tty;
	pty->master = -1;
	pty->slave = -1;
	pty->sigfd = -1;
	pty->child = (pid_t) -1;

	return pty;
}

void ul_free_pty(struct ul_pty *pty)
{
	free(pty);
}

void ul_pty_slave_echo(struct ul_pty *pty, int enable)
{
	assert(pty);
	pty->slave_echo = enable ? 1 : 0;
}

int ul_pty_get_delivered_signal(struct ul_pty *pty)
{
	assert(pty);
	return pty->delivered_signal;
}

struct ul_pty_callbacks *ul_pty_get_callbacks(struct ul_pty *pty)
{
	assert(pty);
	return &pty->callbacks;
}

void ul_pty_set_callback_data(struct ul_pty *pty, void *data)
{
	assert(pty);
	pty->callback_data = data;
}

void ul_pty_set_child(struct ul_pty *pty, pid_t child)
{
	assert(pty);
	pty->child = child;
}

int ul_pty_get_childfd(struct ul_pty *pty)
{
	assert(pty);
	return pty->master;
}

pid_t ul_pty_get_child(struct ul_pty *pty)
{
	assert(pty);
	return pty->child;
}

/* it's active when signals are redurected to sigfd */
int ul_pty_is_running(struct ul_pty *pty)
{
	assert(pty);
	return pty->sigfd >= 0;
}

void ul_pty_set_mainloop_time(struct ul_pty *pty, struct timeval *tv)
{
	assert(pty);
	if (!tv) {
		DBG(IO, ul_debugobj(pty, "mainloop time: clear"));
		timerclear(&pty->next_callback_time);
	} else {
		pty->next_callback_time.tv_sec = tv->tv_sec;
		pty->next_callback_time.tv_usec = tv->tv_usec;
		DBG(IO, ul_debugobj(pty, "mainloop time: %ld.%06ld", tv->tv_sec, tv->tv_usec));
	}
}

static void pty_signals_cleanup(struct ul_pty *pty)
{
	if (pty->sigfd != -1)
		close(pty->sigfd);
	pty->sigfd = -1;

	/* restore original setting */
	sigprocmask(SIG_SETMASK, &pty->orgsig, NULL);
}

/* call me before fork() */
int ul_pty_setup(struct ul_pty *pty)
{
	struct termios slave_attrs;
	sigset_t ourset;
	int rc = 0;

	assert(pty->sigfd == -1);

	/* save the current signals setting */
	sigprocmask(0, NULL, &pty->orgsig);

	if (pty->isterm) {
	        DBG(SETUP, ul_debugobj(pty, "create for terminal"));

		/* original setting of the current terminal */
		if (tcgetattr(STDIN_FILENO, &pty->stdin_attrs) != 0) {
			rc = -errno;
			goto done;
		}
		ioctl(STDIN_FILENO, TIOCGWINSZ, (char *)&pty->win);
		/* create master+slave */
		rc = openpty(&pty->master, &pty->slave, NULL, &pty->stdin_attrs, &pty->win);
		if (rc)
			goto done;

		/* set the current terminal to raw mode; pty_cleanup() reverses this change on exit */
		slave_attrs = pty->stdin_attrs;
		cfmakeraw(&slave_attrs);

		if (pty->slave_echo)
			slave_attrs.c_lflag |= ECHO;
		else
			slave_attrs.c_lflag &= ~ECHO;

		tcsetattr(STDIN_FILENO, TCSANOW, &slave_attrs);
	} else {
	        DBG(SETUP, ul_debugobj(pty, "create for non-terminal"));

		rc = openpty(&pty->master, &pty->slave, NULL, NULL, NULL);
		if (rc)
			goto done;

		tcgetattr(pty->slave, &slave_attrs);

		if (pty->slave_echo)
			slave_attrs.c_lflag |= ECHO;
		else
			slave_attrs.c_lflag &= ~ECHO;

		tcsetattr(pty->slave, TCSANOW, &slave_attrs);
	}

	sigfillset(&ourset);
	if (sigprocmask(SIG_BLOCK, &ourset, NULL)) {
		rc = -errno;
		goto done;
	}

	sigemptyset(&ourset);
	sigaddset(&ourset, SIGCHLD);
	sigaddset(&ourset, SIGWINCH);
	sigaddset(&ourset, SIGALRM);
	sigaddset(&ourset, SIGTERM);
	sigaddset(&ourset, SIGINT);
	sigaddset(&ourset, SIGQUIT);

	if (pty->callbacks.flush_logs)
		sigaddset(&ourset, SIGUSR1);

	if ((pty->sigfd = signalfd(-1, &ourset, SFD_CLOEXEC)) < 0)
		rc = -errno;
done:
	if (rc)
		ul_pty_cleanup(pty);

	DBG(SETUP, ul_debugobj(pty, "pty setup done [master=%d, slave=%d, rc=%d]",
				pty->master, pty->slave, rc));
	return rc;
}

/* cleanup in parent process */
void ul_pty_cleanup(struct ul_pty *pty)
{
	struct termios rtt;

	pty_signals_cleanup(pty);

	if (pty->master == -1 || !pty->isterm)
		return;

	DBG(DONE, ul_debugobj(pty, "cleanup"));
	rtt = pty->stdin_attrs;
	tcsetattr(STDIN_FILENO, TCSADRAIN, &rtt);
}

/* call me in child process */
void ul_pty_init_slave(struct ul_pty *pty)
{
	DBG(SETUP, ul_debugobj(pty, "initialize slave"));

	setsid();

	ioctl(pty->slave, TIOCSCTTY, 1);
	close(pty->master);

	dup2(pty->slave, STDIN_FILENO);
	dup2(pty->slave, STDOUT_FILENO);
	dup2(pty->slave, STDERR_FILENO);

	close(pty->slave);

	if (pty->sigfd >= 0)
		close(pty->sigfd);

	pty->slave = -1;
	pty->master = -1;
	pty->sigfd = -1;

	sigprocmask(SIG_SETMASK, &pty->orgsig, NULL);

	DBG(SETUP, ul_debugobj(pty, "... initialize slave done"));
}

static int write_output(char *obuf, ssize_t bytes)
{
	DBG(IO, ul_debug(" writing output"));

	if (write_all(STDOUT_FILENO, obuf, bytes)) {
		DBG(IO, ul_debug("  writing output *failed*"));
		return -errno;
	}

	return 0;
}

static int write_to_child(struct ul_pty *pty, char *buf, size_t bufsz)
{
	return write_all(pty->master, buf, bufsz);
}

/*
 * The pty is usually faster than shell, so it's a good idea to wait until
 * the previous message has been already read by shell from slave before we
 * write to master. This is necessary especially for EOF situation when we can
 * send EOF to master before shell is fully initialized, to workaround this
 * problem we wait until slave is empty. For example:
 *
 *   echo "date" | su --pty
 *
 * Unfortunately, the child (usually shell) can ignore stdin at all, so we
 * don't wait forever to avoid dead locks...
 *
 * Note that su --pty is primarily designed for interactive sessions as it
 * maintains master+slave tty stuff within the session. Use pipe to write to
 * pty and assume non-interactive (tee-like) behavior is NOT well supported.
 */
void ul_pty_write_eof_to_child(struct ul_pty *pty)
{
	unsigned int tries = 0;
	struct pollfd fds[] = {
	           { .fd = pty->slave, .events = POLLIN }
	};
	char c = DEF_EOF;

	DBG(IO, ul_debugobj(pty, " waiting for empty slave"));
	while (poll(fds, 1, 10) == 1 && tries < 8) {
		DBG(IO, ul_debugobj(pty, "   slave is not empty"));
		xusleep(250000);
		tries++;
	}
	if (tries < 8)
		DBG(IO, ul_debugobj(pty, "   slave is empty now"));

	DBG(IO, ul_debugobj(pty, " sending EOF to master"));
	write_to_child(pty, &c, sizeof(char));
}

static int mainloop_callback(struct ul_pty *pty)
{
	int rc;

	if (!pty->callbacks.mainloop)
		return 0;

	DBG(IO, ul_debugobj(pty, "calling mainloop callback"));
	rc = pty->callbacks.mainloop(pty->callback_data);

	DBG(IO, ul_debugobj(pty, " callback done [rc=%d]", rc));
	return rc;
}

static int handle_io(struct ul_pty *pty, int fd, int *eof)
{
	char buf[BUFSIZ];
	ssize_t bytes;
	int rc = 0;

	DBG(IO, ul_debugobj(pty, " handle I/O on fd=%d", fd));
	*eof = 0;

	/* read from active FD */
	bytes = read(fd, buf, sizeof(buf));
	if (bytes < 0) {
		if (errno == EAGAIN || errno == EINTR)
			return 0;
		return -errno;
	}

	if (bytes == 0) {
		*eof = 1;
		return 0;
	}

	/* from stdin (user) to command */
	if (fd == STDIN_FILENO) {
		DBG(IO, ul_debugobj(pty, " stdin --> master %zd bytes", bytes));

		if (write_to_child(pty, buf, bytes))
			return -errno;

		/* without sync write_output() will write both input &
		 * shell output that looks like double echoing */
		fdatasync(pty->master);

	/* from command (master) to stdout */
	} else if (fd == pty->master) {
		DBG(IO, ul_debugobj(pty, " master --> stdout %zd bytes", bytes));
		write_output(buf, bytes);
	}

	if (pty->callbacks.log_stream_activity)
		rc = pty->callbacks.log_stream_activity(
					pty->callback_data, fd, buf, bytes);

	return rc;
}

void ul_pty_wait_for_child(struct ul_pty *pty)
{
	int status;
	pid_t pid;
	int options = 0;

	if (pty->child == (pid_t) -1)
		return;

	DBG(SIG, ul_debug("waiting for child [child=%d]", (int) pty->child));

	if (ul_pty_is_running(pty)) {
		/* wait for specific child */
		options = WNOHANG;
		for (;;) {
			pid = waitpid(pty->child, &status, options);
			DBG(SIG, ul_debug(" waitpid done [rc=%d]", (int) pid));
			if (pid != (pid_t) - 1) {
				if (pty->callbacks.child_die)
					pty->callbacks.child_die(
							pty->callback_data,
							pty->child, status);
				ul_pty_set_child(pty, (pid_t) -1);
			} else
				break;
		}
	} else {
		/* final wait */
		while ((pid = wait3(&status, options, NULL)) > 0) {
			DBG(SIG, ul_debug(" wait3 done [rc=%d]", (int) pid));
			if (pid == pty->child) {
				if (pty->callbacks.child_die)
					pty->callbacks.child_die(
							pty->callback_data,
							pty->child, status);
				ul_pty_set_child(pty, (pid_t) -1);
			}
		}
	}
}

static int handle_signal(struct ul_pty *pty, int fd)
{
	struct signalfd_siginfo info;
	ssize_t bytes;
	int rc = 0;

	DBG(SIG, ul_debugobj(pty, " handle signal on fd=%d", fd));

	bytes = read(fd, &info, sizeof(info));
	if (bytes != sizeof(info)) {
		if (bytes < 0 && (errno == EAGAIN || errno == EINTR))
			return 0;
		return -errno;
	}

	switch (info.ssi_signo) {
	case SIGCHLD:
		DBG(SIG, ul_debugobj(pty, " get signal SIGCHLD"));

		if (info.ssi_code == CLD_EXITED
		    || info.ssi_code == CLD_KILLED
		    || info.ssi_code == CLD_DUMPED) {

			if (pty->callbacks.child_wait)
				pty->callbacks.child_wait(pty->callback_data,
							  pty->child);
			else
				ul_pty_wait_for_child(pty);

		} else if (info.ssi_status == SIGSTOP && pty->child > 0)
			pty->callbacks.child_sigstop(pty->callback_data,
						     pty->child);

		if (pty->child <= 0) {
			DBG(SIG, ul_debugobj(pty, " no child, setting leaving timeout"));
			pty->poll_timeout = 10;
			timerclear(&pty->next_callback_time);
		}
		return 0;
	case SIGWINCH:
		DBG(SIG, ul_debugobj(pty, " get signal SIGWINCH"));
		if (pty->isterm) {
			ioctl(STDIN_FILENO, TIOCGWINSZ, (char *)&pty->win);
			ioctl(pty->slave, TIOCSWINSZ, (char *)&pty->win);

			if (pty->callbacks.log_signal)
				rc = pty->callbacks.log_signal(pty->callback_data,
							&info, (void *) &pty->win);
		}
		break;
	case SIGTERM:
		/* fallthrough */
	case SIGINT:
		/* fallthrough */
	case SIGQUIT:
		DBG(SIG, ul_debugobj(pty, " get signal SIG{TERM,INT,QUIT}"));
		pty->delivered_signal = info.ssi_signo;
                /* Child termination is going to generate SIGCHILD (see above) */
		if (pty->child > 0)
	                kill(pty->child, SIGTERM);

		if (pty->callbacks.log_signal)
			rc = pty->callbacks.log_signal(pty->callback_data,
					&info, (void *) &pty->win);
		break;
	case SIGUSR1:
		DBG(SIG, ul_debugobj(pty, " get signal SIGUSR1"));
		if (pty->callbacks.flush_logs)
			rc = pty->callbacks.flush_logs(pty->callback_data);
		break;
	default:
		abort();
	}

	return rc;
}

/* loop in parent */
int ul_pty_proxy_master(struct ul_pty *pty)
{
	int rc = 0, ret, eof = 0;
	enum {
		POLLFD_SIGNAL = 0,
		POLLFD_MASTER,
		POLLFD_STDIN

	};
	struct pollfd pfd[] = {
		[POLLFD_SIGNAL] = { .fd = -1,		.events = POLLIN | POLLERR | POLLHUP },
		[POLLFD_MASTER] = { .fd = pty->master,  .events = POLLIN | POLLERR | POLLHUP },
		[POLLFD_STDIN]	= { .fd = STDIN_FILENO, .events = POLLIN | POLLERR | POLLHUP }
	};

	/* We use signalfd and standard signals by handlers are blocked
	 * at all
	 */
	assert(pty->sigfd >= 0);

	pfd[POLLFD_SIGNAL].fd = pty->sigfd;
	pty->poll_timeout = -1;

	while (!pty->delivered_signal) {
		size_t i;
		int errsv, timeout;

		DBG(IO, ul_debugobj(pty, "--poll() loop--"));

		/* note, callback usually updates @next_callback_time */
		if (timerisset(&pty->next_callback_time)) {
			struct timeval now;

			DBG(IO, ul_debugobj(pty, " callback requested"));
			gettime_monotonic(&now);
			if (timercmp(&now, &pty->next_callback_time, >)) {
				rc = mainloop_callback(pty);
				if (rc)
					break;
			}
		}

		/* set timeout */
		if (timerisset(&pty->next_callback_time)) {
			struct timeval now, rest;

			gettime_monotonic(&now);
			timersub(&pty->next_callback_time, &now, &rest);
			timeout = (rest.tv_sec * 1000) +  (rest.tv_usec / 1000);
		} else
			timeout = pty->poll_timeout;

		/* wait for input, signal or timeout */
		DBG(IO, ul_debugobj(pty, "calling poll() [timeout=%dms]", timeout));
		ret = poll(pfd, ARRAY_SIZE(pfd), timeout);

		errsv = errno;
		DBG(IO, ul_debugobj(pty, "poll() rc=%d", ret));

		/* error */
		if (ret < 0) {
			if (errsv == EAGAIN)
				continue;
			rc = -errno;
			break;
		}

		/* timeout */
		if (ret == 0) {
			if (timerisset(&pty->next_callback_time)) {
				rc = mainloop_callback(pty);
				if (rc == 0)
					continue;
			} else
				rc = 0;

			DBG(IO, ul_debugobj(pty, "leaving poll() loop [timeout=%d, rc=%d]", timeout, rc));
			break;
		}
		/* event */
		for (i = 0; i < ARRAY_SIZE(pfd); i++) {
			rc = 0;

			if (pfd[i].revents == 0)
				continue;

			DBG(IO, ul_debugobj(pty, " active pfd[%s].fd=%d %s %s %s %s",
						i == POLLFD_STDIN  ? "stdin" :
						i == POLLFD_MASTER ? "master" :
						i == POLLFD_SIGNAL ? "signal" : "???",
						pfd[i].fd,
						pfd[i].revents & POLLIN  ? "POLLIN" : "",
						pfd[i].revents & POLLHUP ? "POLLHUP" : "",
						pfd[i].revents & POLLERR ? "POLLERR" : "",
						pfd[i].revents & POLLNVAL ? "POLLNVAL" : ""));

			switch (i) {
			case POLLFD_STDIN:
			case POLLFD_MASTER:
				/* data */
				if (pfd[i].revents & POLLIN)
					rc = handle_io(pty, pfd[i].fd, &eof);
				/* EOF maybe detected by two ways:
				 *	A) poll() return POLLHUP event after close()
				 *	B) read() returns 0 (no data)
				 *
				 * POLLNVAL means that fd is closed.
				 */
				if ((pfd[i].revents & POLLHUP) || (pfd[i].revents & POLLNVAL) || eof) {
					DBG(IO, ul_debugobj(pty, " ignore FD"));
					pfd[i].fd = -1;
					if (i == POLLFD_STDIN) {
						ul_pty_write_eof_to_child(pty);
						DBG(IO, ul_debugobj(pty, "  ignore STDIN"));
					}
				}
				continue;
			case POLLFD_SIGNAL:
				rc = handle_signal(pty, pfd[i].fd);
				break;
			}
			if (rc)
				break;
		}
	}

	pty_signals_cleanup(pty);

	DBG(IO, ul_debug("poll() done [signal=%d, rc=%d]", pty->delivered_signal, rc));
	return rc;
}

#ifdef TEST_PROGRAM_PTY
/*
 * $ make test_pty
 * $ ./test_pty
 *
 * ... and see for example tty(1) or "ps afu"
 */
static void child_sigstop(void *data __attribute__((__unused__)), pid_t child)
{
	kill(getpid(), SIGSTOP);
	kill(child, SIGCONT);
}

int main(int argc, char *argv[])
{
	struct ul_pty_callbacks *cb;
	const char *shell, *command = NULL, *shname = NULL;
	int caught_signal = 0;
	pid_t child;
	struct ul_pty *pty;

	shell = getenv("SHELL");
	if (shell == NULL)
		shell = _PATH_BSHELL;
	if (argc == 2)
		command = argv[1];

	ul_pty_init_debug(0);

	pty = ul_new_pty(isatty(STDIN_FILENO));
	if (!pty)
		err(EXIT_FAILURE, "failed to allocate PTY handler");

	cb = ul_pty_get_callbacks(pty);
	cb->child_sigstop = child_sigstop;

	if (ul_pty_setup(pty))
		err(EXIT_FAILURE, "failed to create pseudo-terminal");

	fflush(stdout);			/* ??? */

	switch ((int) (child = fork())) {
	case -1: /* error */
		ul_pty_cleanup(pty);
		err(EXIT_FAILURE, "cannot create child process");
		break;

	case 0: /* child */
		ul_pty_init_slave(pty);

		signal(SIGTERM, SIG_DFL); /* because /etc/csh.login */

		shname = strrchr(shell, '/');
		shname = shname ? shname + 1 : shell;

		if (command)
			execl(shell, shname, "-c", command, NULL);
		else
			execl(shell, shname, "-i", NULL);
		err(EXIT_FAILURE, "failed to execute %s", shell);
		break;

	default:
		break;
	}

	/* parent */
	ul_pty_set_child(pty, child);

	/* this is the main loop */
	ul_pty_proxy_master(pty);

	/* all done; cleanup and kill */
	caught_signal = ul_pty_get_delivered_signal(pty);

	if (!caught_signal && ul_pty_get_child(pty) != (pid_t)-1)
		ul_pty_wait_for_child(pty);	/* final wait */

	if (caught_signal && ul_pty_get_child(pty) != (pid_t)-1) {
		fprintf(stderr, "\nSession terminated, killing shell...");
		kill(child, SIGTERM);
		sleep(2);
		kill(child, SIGKILL);
		fprintf(stderr, " ...killed.\n");
	}

	ul_pty_cleanup(pty);
	ul_free_pty(pty);
	return EXIT_SUCCESS;
}

#endif /* TEST_PROGRAM */
Commit	Line	Data
6954895c KZ	1	/*
	2	* This is pseudo-terminal container for child process where parent creates a
	3	* proxy between the current std{in,out,etrr} and the child's pty. Advantages:
	4	*
	5	* - child has no access to parent's terminal (e.g. su --pty)
	6	* - parent can log all traffic between user and child's terminall (e.g. script(1))
	7	* - it's possible to start commands on terminal although parent has no terminal
	8	*
	9	* This code is in the public domain; do with it what you wish.
	10	*
	11	* Written by Karel Zak <kzak@redhat.com> in Jul 2019
	12	*/
	13	#include <stdio.h>
	14	#include <stdlib.h>
	15	#include <pty.h>
	16	#include <poll.h>
	17	#include <sys/signalfd.h>
	18	#include <paths.h>
	19	#include <sys/types.h>
	20	#include <sys/wait.h>
	21
	22	#include "c.h"
	23	#include "all-io.h"
	24	#include "ttyutils.h"
	25	#include "pty-session.h"
4d5b2fed	26	#include "monotonic.h"
6954895c KZ	27	#include "debug.h"
	28
	29	static UL_DEBUG_DEFINE_MASK(ulpty);
	30	UL_DEBUG_DEFINE_MASKNAMES(ulpty) = UL_DEBUG_EMPTY_MASKNAMES;
	31
	32	#define ULPTY_DEBUG_INIT (1 << 1)
	33	#define ULPTY_DEBUG_SETUP (1 << 2)
	34	#define ULPTY_DEBUG_SIG (1 << 3)
	35	#define ULPTY_DEBUG_IO (1 << 4)
	36	#define ULPTY_DEBUG_DONE (1 << 5)
	37	#define ULPTY_DEBUG_ALL 0xFFFF
	38
	39	#define DBG(m, x) __UL_DBG(ulpty, ULPTY_DEBUG_, m, x)
	40	#define ON_DBG(m, x) __UL_DBG_CALL(ulpty, ULPTY_DEBUG_, m, x)
	41
	42	#define UL_DEBUG_CURRENT_MASK UL_DEBUG_MASK(ulpty)
	43	#include "debugobj.h"
	44
	45	void ul_pty_init_debug(int mask)
	46	{
	47	if (ulpty_debug_mask)
	48	return;
	49	__UL_INIT_DEBUG_FROM_ENV(ulpty, ULPTY_DEBUG_, mask, ULPTY_DEBUG);
	50	}
	51
	52	struct ul_pty *ul_new_pty(int is_stdin_tty)
	53	{
	54	struct ul_pty pty = calloc(1, sizeof(pty));
	55
	56	if (!pty)
	57	return NULL;
	58
	59	DBG(SETUP, ul_debugobj(pty, "alloc handler"));
	60	pty->isterm = is_stdin_tty;
	61	pty->master = -1;
	62	pty->slave = -1;
	63	pty->sigfd = -1;
	64	pty->child = (pid_t) -1;
	65
	66	return pty;
	67	}
	68
ab61a038	69	void ul_free_pty(struct ul_pty *pty)
6954895c	70	{
ab61a038	71	free(pty);
6954895c KZ	72	}
6954895c KZ	73
1eee1acb	74	void ul_pty_slave_echo(struct ul_pty *pty, int enable)
4169bcb7 KZ	75	{
4169bcb7 KZ	76	assert(pty);
1eee1acb	77	pty->slave_echo = enable ? 1 : 0;
4169bcb7	78	}
ab61a038	79
6954895c KZ	80	int ul_pty_get_delivered_signal(struct ul_pty *pty)
	81	{
	82	assert(pty);
	83	return pty->delivered_signal;
	84	}
	85
	86	struct ul_pty_callbacks ul_pty_get_callbacks(struct ul_pty pty)
	87	{
	88	assert(pty);
	89	return &pty->callbacks;
	90	}
	91
	92	void ul_pty_set_callback_data(struct ul_pty pty, void data)
	93	{
	94	assert(pty);
	95	pty->callback_data = data;
	96	}
	97
	98	void ul_pty_set_child(struct ul_pty *pty, pid_t child)
	99	{
	100	assert(pty);
	101	pty->child = child;
	102	}
	103
4d5b2fed KZ	104	int ul_pty_get_childfd(struct ul_pty *pty)
	105	{
	106	assert(pty);
	107	return pty->master;
	108	}
	109
bdd43357 KZ	110	pid_t ul_pty_get_child(struct ul_pty *pty)
	111	{
	112	assert(pty);
	113	return pty->child;
	114	}
	115
6954895c KZ	116	/* it's active when signals are redurected to sigfd */
	117	int ul_pty_is_running(struct ul_pty *pty)
	118	{
	119	assert(pty);
	120	return pty->sigfd >= 0;
	121	}
	122
4d5b2fed KZ	123	void ul_pty_set_mainloop_time(struct ul_pty pty, struct timeval tv)
	124	{
	125	assert(pty);
	126	if (!tv) {
	127	DBG(IO, ul_debugobj(pty, "mainloop time: clear"));
	128	timerclear(&pty->next_callback_time);
	129	} else {
	130	pty->next_callback_time.tv_sec = tv->tv_sec;
	131	pty->next_callback_time.tv_usec = tv->tv_usec;
	132	DBG(IO, ul_debugobj(pty, "mainloop time: %ld.%06ld", tv->tv_sec, tv->tv_usec));
	133	}
	134	}
	135
b1154c4e KZ	136	static void pty_signals_cleanup(struct ul_pty *pty)
	137	{
	138	if (pty->sigfd != -1)
	139	close(pty->sigfd);
	140	pty->sigfd = -1;
	141
	142	/* restore original setting */
	143	sigprocmask(SIG_SETMASK, &pty->orgsig, NULL);
	144	}
	145
6954895c KZ	146	/* call me before fork() */
	147	int ul_pty_setup(struct ul_pty *pty)
	148	{
	149	struct termios slave_attrs;
b1154c4e KZ	150	sigset_t ourset;
	151	int rc = 0;
	152
	153	assert(pty->sigfd == -1);
6954895c	154
ab61a038 KZ	155	/* save the current signals setting */
	156	sigprocmask(0, NULL, &pty->orgsig);
	157
6954895c KZ	158	if (pty->isterm) {
	159	DBG(SETUP, ul_debugobj(pty, "create for terminal"));
	160
	161	/* original setting of the current terminal */
b1154c4e KZ	162	if (tcgetattr(STDIN_FILENO, &pty->stdin_attrs) != 0) {
	163	rc = -errno;
	164	goto done;
	165	}
6954895c KZ	166	ioctl(STDIN_FILENO, TIOCGWINSZ, (char *)&pty->win);
	167	/* create master+slave */
	168	rc = openpty(&pty->master, &pty->slave, NULL, &pty->stdin_attrs, &pty->win);
b1154c4e KZ	169	if (rc)
b1154c4e KZ	170	goto done;
6954895c KZ	171
	172	/* set the current terminal to raw mode; pty_cleanup() reverses this change on exit */
	173	slave_attrs = pty->stdin_attrs;
	174	cfmakeraw(&slave_attrs);
1eee1acb KZ	175
	176	if (pty->slave_echo)
	177	slave_attrs.c_lflag \|= ECHO;
	178	else
	179	slave_attrs.c_lflag &= ~ECHO;
	180
6954895c KZ	181	tcsetattr(STDIN_FILENO, TCSANOW, &slave_attrs);
	182	} else {
	183	DBG(SETUP, ul_debugobj(pty, "create for non-terminal"));
6954895c	184
1eee1acb KZ	185	rc = openpty(&pty->master, &pty->slave, NULL, NULL, NULL);
1eee1acb KZ	186	if (rc)
b1154c4e	187	goto done;
1eee1acb KZ	188
	189	tcgetattr(pty->slave, &slave_attrs);
	190
	191	if (pty->slave_echo)
	192	slave_attrs.c_lflag \|= ECHO;
	193	else
	194	slave_attrs.c_lflag &= ~ECHO;
	195
	196	tcsetattr(pty->slave, TCSANOW, &slave_attrs);
b1154c4e KZ	197	}
	198
	199	sigfillset(&ourset);
	200	if (sigprocmask(SIG_BLOCK, &ourset, NULL)) {
	201	rc = -errno;
	202	goto done;
6954895c KZ	203	}
6954895c KZ	204
b1154c4e KZ	205	sigemptyset(&ourset);
	206	sigaddset(&ourset, SIGCHLD);
	207	sigaddset(&ourset, SIGWINCH);
	208	sigaddset(&ourset, SIGALRM);
	209	sigaddset(&ourset, SIGTERM);
	210	sigaddset(&ourset, SIGINT);
	211	sigaddset(&ourset, SIGQUIT);
	212
7727be1a KZ	213	if (pty->callbacks.flush_logs)
	214	sigaddset(&ourset, SIGUSR1);
	215
b1154c4e KZ	216	if ((pty->sigfd = signalfd(-1, &ourset, SFD_CLOEXEC)) < 0)
	217	rc = -errno;
	218	done:
	219	if (rc)
	220	ul_pty_cleanup(pty);
	221
6954895c KZ	222	DBG(SETUP, ul_debugobj(pty, "pty setup done [master=%d, slave=%d, rc=%d]",
	223	pty->master, pty->slave, rc));
	224	return rc;
	225	}
	226
	227	/* cleanup in parent process */
	228	void ul_pty_cleanup(struct ul_pty *pty)
	229	{
	230	struct termios rtt;
	231
b1154c4e KZ	232	pty_signals_cleanup(pty);
b1154c4e KZ	233
6954895c KZ	234	if (pty->master == -1 \|\| !pty->isterm)
	235	return;
	236
	237	DBG(DONE, ul_debugobj(pty, "cleanup"));
	238	rtt = pty->stdin_attrs;
	239	tcsetattr(STDIN_FILENO, TCSADRAIN, &rtt);
	240	}
	241
	242	/* call me in child process */
	243	void ul_pty_init_slave(struct ul_pty *pty)
	244	{
	245	DBG(SETUP, ul_debugobj(pty, "initialize slave"));
	246
	247	setsid();
	248
	249	ioctl(pty->slave, TIOCSCTTY, 1);
	250	close(pty->master);
	251
	252	dup2(pty->slave, STDIN_FILENO);
	253	dup2(pty->slave, STDOUT_FILENO);
	254	dup2(pty->slave, STDERR_FILENO);
	255
	256	close(pty->slave);
	257
	258	if (pty->sigfd >= 0)
	259	close(pty->sigfd);
	260
	261	pty->slave = -1;
	262	pty->master = -1;
	263	pty->sigfd = -1;
	264
	265	sigprocmask(SIG_SETMASK, &pty->orgsig, NULL);
	266
	267	DBG(SETUP, ul_debugobj(pty, "... initialize slave done"));
	268	}
	269
	270	static int write_output(char *obuf, ssize_t bytes)
	271	{
	272	DBG(IO, ul_debug(" writing output"));
	273
	274	if (write_all(STDOUT_FILENO, obuf, bytes)) {
	275	DBG(IO, ul_debug(" writing output failed"));
	276	return -errno;
	277	}
	278
	279	return 0;
	280	}
	281
4d5b2fed	282	static int write_to_child(struct ul_pty pty, char buf, size_t bufsz)
6954895c KZ	283	{
	284	return write_all(pty->master, buf, bufsz);
	285	}
	286
	287	/*
	288	* The pty is usually faster than shell, so it's a good idea to wait until
	289	* the previous message has been already read by shell from slave before we
	290	* write to master. This is necessary especially for EOF situation when we can
	291	* send EOF to master before shell is fully initialized, to workaround this
	292	* problem we wait until slave is empty. For example:
	293	*
	294	* echo "date" \| su --pty
	295	*
	296	* Unfortunately, the child (usually shell) can ignore stdin at all, so we
	297	* don't wait forever to avoid dead locks...
	298	*
	299	* Note that su --pty is primarily designed for interactive sessions as it
	300	* maintains master+slave tty stuff within the session. Use pipe to write to
	301	* pty and assume non-interactive (tee-like) behavior is NOT well supported.
	302	*/
95d255a8	303	void ul_pty_write_eof_to_child(struct ul_pty *pty)
6954895c KZ	304	{
	305	unsigned int tries = 0;
	306	struct pollfd fds[] = {
	307	{ .fd = pty->slave, .events = POLLIN }
	308	};
	309	char c = DEF_EOF;
	310
	311	DBG(IO, ul_debugobj(pty, " waiting for empty slave"));
	312	while (poll(fds, 1, 10) == 1 && tries < 8) {
	313	DBG(IO, ul_debugobj(pty, " slave is not empty"));
	314	xusleep(250000);
	315	tries++;
	316	}
	317	if (tries < 8)
	318	DBG(IO, ul_debugobj(pty, " slave is empty now"));
	319
	320	DBG(IO, ul_debugobj(pty, " sending EOF to master"));
	321	write_to_child(pty, &c, sizeof(char));
	322	}
	323
4d5b2fed KZ	324	static int mainloop_callback(struct ul_pty *pty)
4d5b2fed KZ	325	{
f896aef3 KZ	326	int rc;
f896aef3 KZ	327
4d5b2fed KZ	328	if (!pty->callbacks.mainloop)
	329	return 0;
	330
	331	DBG(IO, ul_debugobj(pty, "calling mainloop callback"));
f896aef3 KZ	332	rc = pty->callbacks.mainloop(pty->callback_data);
	333
	334	DBG(IO, ul_debugobj(pty, " callback done [rc=%d]", rc));
	335	return rc;
4d5b2fed KZ	336	}
4d5b2fed KZ	337
6954895c KZ	338	static int handle_io(struct ul_pty pty, int fd, int eof)
	339	{
	340	char buf[BUFSIZ];
	341	ssize_t bytes;
4f7f723b	342	int rc = 0;
6954895c	343
c4bacbd1	344	DBG(IO, ul_debugobj(pty, " handle I/O on fd=%d", fd));
6954895c KZ	345	*eof = 0;
	346
	347	/* read from active FD */
	348	bytes = read(fd, buf, sizeof(buf));
	349	if (bytes < 0) {
	350	if (errno == EAGAIN \|\| errno == EINTR)
	351	return 0;
	352	return -errno;
	353	}
	354
	355	if (bytes == 0) {
	356	*eof = 1;
	357	return 0;
	358	}
	359
	360	/* from stdin (user) to command */
	361	if (fd == STDIN_FILENO) {
	362	DBG(IO, ul_debugobj(pty, " stdin --> master %zd bytes", bytes));
	363
	364	if (write_to_child(pty, buf, bytes))
	365	return -errno;
	366
	367	/* without sync write_output() will write both input &
	368	* shell output that looks like double echoing */
	369	fdatasync(pty->master);
	370
	371	/* from command (master) to stdout */
	372	} else if (fd == pty->master) {
	373	DBG(IO, ul_debugobj(pty, " master --> stdout %zd bytes", bytes));
	374	write_output(buf, bytes);
	375	}
	376
4f7f723b KZ	377	if (pty->callbacks.log_stream_activity)
	378	rc = pty->callbacks.log_stream_activity(
	379	pty->callback_data, fd, buf, bytes);
	380
	381	return rc;
6954895c KZ	382	}
6954895c KZ	383
bdd43357 KZ	384	void ul_pty_wait_for_child(struct ul_pty *pty)
	385	{
	386	int status;
	387	pid_t pid;
	388	int options = 0;
	389
	390	if (pty->child == (pid_t) -1)
	391	return;
	392
125314c0	393	DBG(SIG, ul_debug("waiting for child [child=%d]", (int) pty->child));
bdd43357 KZ	394
	395	if (ul_pty_is_running(pty)) {
	396	/* wait for specific child */
	397	options = WNOHANG;
	398	for (;;) {
	399	pid = waitpid(pty->child, &status, options);
125314c0	400	DBG(SIG, ul_debug(" waitpid done [rc=%d]", (int) pid));
bdd43357 KZ	401	if (pid != (pid_t) - 1) {
	402	if (pty->callbacks.child_die)
	403	pty->callbacks.child_die(
	404	pty->callback_data,
	405	pty->child, status);
	406	ul_pty_set_child(pty, (pid_t) -1);
	407	} else
	408	break;
	409	}
	410	} else {
	411	/* final wait */
	412	while ((pid = wait3(&status, options, NULL)) > 0) {
125314c0	413	DBG(SIG, ul_debug(" wait3 done [rc=%d]", (int) pid));
bdd43357 KZ	414	if (pid == pty->child) {
	415	if (pty->callbacks.child_die)
	416	pty->callbacks.child_die(
	417	pty->callback_data,
	418	pty->child, status);
	419	ul_pty_set_child(pty, (pid_t) -1);
	420	}
	421	}
	422	}
	423	}
	424
6954895c KZ	425	static int handle_signal(struct ul_pty *pty, int fd)
	426	{
	427	struct signalfd_siginfo info;
	428	ssize_t bytes;
4f7f723b	429	int rc = 0;
6954895c	430
c4bacbd1	431	DBG(SIG, ul_debugobj(pty, " handle signal on fd=%d", fd));
6954895c KZ	432
	433	bytes = read(fd, &info, sizeof(info));
	434	if (bytes != sizeof(info)) {
	435	if (bytes < 0 && (errno == EAGAIN \|\| errno == EINTR))
	436	return 0;
	437	return -errno;
	438	}
	439
	440	switch (info.ssi_signo) {
	441	case SIGCHLD:
	442	DBG(SIG, ul_debugobj(pty, " get signal SIGCHLD"));
	443
	444	if (info.ssi_code == CLD_EXITED
	445	\|\| info.ssi_code == CLD_KILLED
bdd43357 KZ	446	\|\| info.ssi_code == CLD_DUMPED) {
	447
	448	if (pty->callbacks.child_wait)
	449	pty->callbacks.child_wait(pty->callback_data,
	450	pty->child);
	451	else
	452	ul_pty_wait_for_child(pty);
6954895c	453
bdd43357 KZ	454	} else if (info.ssi_status == SIGSTOP && pty->child > 0)
	455	pty->callbacks.child_sigstop(pty->callback_data,
	456	pty->child);
6954895c	457
984082fa	458	if (pty->child <= 0) {
125314c0	459	DBG(SIG, ul_debugobj(pty, " no child, setting leaving timeout"));
6954895c	460	pty->poll_timeout = 10;
984082fa KZ	461	timerclear(&pty->next_callback_time);
984082fa KZ	462	}
6954895c KZ	463	return 0;
	464	case SIGWINCH:
	465	DBG(SIG, ul_debugobj(pty, " get signal SIGWINCH"));
	466	if (pty->isterm) {
	467	ioctl(STDIN_FILENO, TIOCGWINSZ, (char *)&pty->win);
	468	ioctl(pty->slave, TIOCSWINSZ, (char *)&pty->win);
4f7f723b KZ	469
	470	if (pty->callbacks.log_signal)
	471	rc = pty->callbacks.log_signal(pty->callback_data,
	472	&info, (void *) &pty->win);
6954895c KZ	473	}
	474	break;
	475	case SIGTERM:
	476	/* fallthrough */
	477	case SIGINT:
	478	/* fallthrough */
	479	case SIGQUIT:
	480	DBG(SIG, ul_debugobj(pty, " get signal SIG{TERM,INT,QUIT}"));
	481	pty->delivered_signal = info.ssi_signo;
	482	/* Child termination is going to generate SIGCHILD (see above) */
	483	if (pty->child > 0)
	484	kill(pty->child, SIGTERM);
4f7f723b KZ	485
	486	if (pty->callbacks.log_signal)
	487	rc = pty->callbacks.log_signal(pty->callback_data,
	488	&info, (void *) &pty->win);
6954895c	489	break;
7727be1a KZ	490	case SIGUSR1:
	491	DBG(SIG, ul_debugobj(pty, " get signal SIGUSR1"));
	492	if (pty->callbacks.flush_logs)
	493	rc = pty->callbacks.flush_logs(pty->callback_data);
	494	break;
6954895c KZ	495	default:
	496	abort();
	497	}
	498
4f7f723b	499	return rc;
6954895c KZ	500	}
	501
	502	/* loop in parent */
	503	int ul_pty_proxy_master(struct ul_pty *pty)
	504	{
6954895c KZ	505	int rc = 0, ret, eof = 0;
	506	enum {
	507	POLLFD_SIGNAL = 0,
	508	POLLFD_MASTER,
	509	POLLFD_STDIN
	510
	511	};
	512	struct pollfd pfd[] = {
	513	[POLLFD_SIGNAL] = { .fd = -1, .events = POLLIN \| POLLERR \| POLLHUP },
	514	[POLLFD_MASTER] = { .fd = pty->master, .events = POLLIN \| POLLERR \| POLLHUP },
	515	[POLLFD_STDIN] = { .fd = STDIN_FILENO, .events = POLLIN \| POLLERR \| POLLHUP }
	516	};
	517
	518	/* We use signalfd and standard signals by handlers are blocked
	519	* at all
	520	*/
b1154c4e	521	assert(pty->sigfd >= 0);
6954895c KZ	522
	523	pfd[POLLFD_SIGNAL].fd = pty->sigfd;
	524	pty->poll_timeout = -1;
	525
	526	while (!pty->delivered_signal) {
	527	size_t i;
4d5b2fed KZ	528	int errsv, timeout;
	529
	530	DBG(IO, ul_debugobj(pty, "--poll() loop--"));
	531
	532	/* note, callback usually updates @next_callback_time */
	533	if (timerisset(&pty->next_callback_time)) {
	534	struct timeval now;
	535
	536	DBG(IO, ul_debugobj(pty, " callback requested"));
	537	gettime_monotonic(&now);
	538	if (timercmp(&now, &pty->next_callback_time, >)) {
	539	rc = mainloop_callback(pty);
	540	if (rc)
	541	break;
	542	}
	543	}
	544
	545	/* set timeout */
	546	if (timerisset(&pty->next_callback_time)) {
	547	struct timeval now, rest;
	548
	549	gettime_monotonic(&now);
	550	timersub(&pty->next_callback_time, &now, &rest);
	551	timeout = (rest.tv_sec * 1000) + (rest.tv_usec / 1000);
	552	} else
	553	timeout = pty->poll_timeout;
6954895c	554
4d5b2fed KZ	555	/* wait for input, signal or timeout */
	556	DBG(IO, ul_debugobj(pty, "calling poll() [timeout=%dms]", timeout));
	557	ret = poll(pfd, ARRAY_SIZE(pfd), timeout);
6954895c	558
6954895c KZ	559	errsv = errno;
	560	DBG(IO, ul_debugobj(pty, "poll() rc=%d", ret));
	561
4d5b2fed	562	/* error */
6954895c KZ	563	if (ret < 0) {
	564	if (errsv == EAGAIN)
	565	continue;
	566	rc = -errno;
	567	break;
	568	}
4d5b2fed KZ	569
4d5b2fed KZ	570	/* timeout */
6954895c	571	if (ret == 0) {
4d5b2fed KZ	572	if (timerisset(&pty->next_callback_time)) {
	573	rc = mainloop_callback(pty);
	574	if (rc == 0)
	575	continue;
	576	} else
	577	rc = 0;
	578
984082fa	579	DBG(IO, ul_debugobj(pty, "leaving poll() loop [timeout=%d, rc=%d]", timeout, rc));
6954895c KZ	580	break;
6954895c KZ	581	}
4d5b2fed	582	/* event */
6954895c KZ	583	for (i = 0; i < ARRAY_SIZE(pfd); i++) {
	584	rc = 0;
	585
	586	if (pfd[i].revents == 0)
	587	continue;
	588
f896aef3	589	DBG(IO, ul_debugobj(pty, " active pfd[%s].fd=%d %s %s %s %s",
6954895c KZ	590	i == POLLFD_STDIN ? "stdin" :
	591	i == POLLFD_MASTER ? "master" :
	592	i == POLLFD_SIGNAL ? "signal" : "???",
	593	pfd[i].fd,
	594	pfd[i].revents & POLLIN ? "POLLIN" : "",
	595	pfd[i].revents & POLLHUP ? "POLLHUP" : "",
f896aef3 KZ	596	pfd[i].revents & POLLERR ? "POLLERR" : "",
	597	pfd[i].revents & POLLNVAL ? "POLLNVAL" : ""));
	598
6954895c KZ	599	switch (i) {
	600	case POLLFD_STDIN:
	601	case POLLFD_MASTER:
	602	/* data */
	603	if (pfd[i].revents & POLLIN)
	604	rc = handle_io(pty, pfd[i].fd, &eof);
	605	/* EOF maybe detected by two ways:
	606	* A) poll() return POLLHUP event after close()
f896aef3 KZ	607	* B) read() returns 0 (no data)
	608	*
	609	* POLLNVAL means that fd is closed.
	610	*/
	611	if ((pfd[i].revents & POLLHUP) \|\| (pfd[i].revents & POLLNVAL) \|\| eof) {
6954895c KZ	612	DBG(IO, ul_debugobj(pty, " ignore FD"));
	613	pfd[i].fd = -1;
	614	if (i == POLLFD_STDIN) {
95d255a8	615	ul_pty_write_eof_to_child(pty);
6954895c KZ	616	DBG(IO, ul_debugobj(pty, " ignore STDIN"));
	617	}
	618	}
	619	continue;
	620	case POLLFD_SIGNAL:
	621	rc = handle_signal(pty, pfd[i].fd);
	622	break;
	623	}
	624	if (rc)
	625	break;
	626	}
	627	}
	628
b1154c4e	629	pty_signals_cleanup(pty);
6954895c KZ	630
	631	DBG(IO, ul_debug("poll() done [signal=%d, rc=%d]", pty->delivered_signal, rc));
	632	return rc;
	633	}
	634
	635	#ifdef TEST_PROGRAM_PTY
	636	/*
	637	* $ make test_pty
	638	* $ ./test_pty
	639	*
	640	* ... and see for example tty(1) or "ps afu"
	641	*/
bdd43357	642	static void child_sigstop(void *data __attribute__((__unused__)), pid_t child)
6954895c	643	{
6954895c	644	kill(getpid(), SIGSTOP);
bdd43357	645	kill(child, SIGCONT);
6954895c KZ	646	}
	647
	648	int main(int argc, char *argv[])
	649	{
6954895c KZ	650	struct ul_pty_callbacks *cb;
	651	const char shell, command = NULL, *shname = NULL;
	652	int caught_signal = 0;
bdd43357	653	pid_t child;
8cf448e9	654	struct ul_pty *pty;
6954895c KZ	655
	656	shell = getenv("SHELL");
	657	if (shell == NULL)
	658	shell = _PATH_BSHELL;
	659	if (argc == 2)
	660	command = argv[1];
	661
	662	ul_pty_init_debug(0);
	663
8cf448e9 KZ	664	pty = ul_new_pty(isatty(STDIN_FILENO));
8cf448e9 KZ	665	if (!pty)
6954895c KZ	666	err(EXIT_FAILURE, "failed to allocate PTY handler");
6954895c KZ	667
8cf448e9	668	cb = ul_pty_get_callbacks(pty);
6954895c KZ	669	cb->child_sigstop = child_sigstop;
6954895c KZ	670
8cf448e9	671	if (ul_pty_setup(pty))
6954895c KZ	672	err(EXIT_FAILURE, "failed to create pseudo-terminal");
	673
	674	fflush(stdout); /* ??? */
	675
bdd43357	676	switch ((int) (child = fork())) {
6954895c	677	case -1: /* error */
8cf448e9	678	ul_pty_cleanup(pty);
6954895c KZ	679	err(EXIT_FAILURE, "cannot create child process");
	680	break;
	681
	682	case 0: /* child */
8cf448e9	683	ul_pty_init_slave(pty);
6954895c KZ	684
	685	signal(SIGTERM, SIG_DFL); /* because /etc/csh.login */
	686
	687	shname = strrchr(shell, '/');
	688	shname = shname ? shname + 1 : shell;
	689
	690	if (command)
	691	execl(shell, shname, "-c", command, NULL);
	692	else
	693	execl(shell, shname, "-i", NULL);
	694	err(EXIT_FAILURE, "failed to execute %s", shell);
	695	break;
	696
	697	default:
	698	break;
	699	}
	700
	701	/* parent */
8cf448e9	702	ul_pty_set_child(pty, child);
6954895c KZ	703
6954895c KZ	704	/* this is the main loop */
8cf448e9	705	ul_pty_proxy_master(pty);
6954895c KZ	706
6954895c KZ	707	/* all done; cleanup and kill */
8cf448e9	708	caught_signal = ul_pty_get_delivered_signal(pty);
6954895c	709
8cf448e9 KZ	710	if (!caught_signal && ul_pty_get_child(pty) != (pid_t)-1)
8cf448e9 KZ	711	ul_pty_wait_for_child(pty); /* final wait */
6954895c	712
8cf448e9	713	if (caught_signal && ul_pty_get_child(pty) != (pid_t)-1) {
6954895c	714	fprintf(stderr, "\nSession terminated, killing shell...");
bdd43357	715	kill(child, SIGTERM);
6954895c	716	sleep(2);
bdd43357	717	kill(child, SIGKILL);
6954895c KZ	718	fprintf(stderr, " ...killed.\n");
	719	}
	720
8cf448e9 KZ	721	ul_pty_cleanup(pty);
8cf448e9 KZ	722	ul_free_pty(pty);
6954895c KZ	723	return EXIT_SUCCESS;
	724	}
	725
	726	#endif /* TEST_PROGRAM */
	727