2 * Pseudo-tty backend for pterm.
5 #define _XOPEN_SOURCE 600
6 #define _XOPEN_SOURCE_EXTENDED
20 #include <sys/types.h>
23 #include <sys/ioctl.h>
37 #define UTMP_FILE "/var/run/utmp"
40 #define WTMP_FILE "/var/log/wtmp"
44 #define LASTLOG_FILE _PATH_LASTLOG
46 #define LASTLOG_FILE "/var/log/lastlog"
51 * Set up a default for vaguely sane systems. The idea is that if
52 * OMIT_UTMP is not defined, then at least one of the symbols which
53 * enable particular forms of utmp processing should be, if only so
54 * that a link error can warn you that you should have defined
55 * OMIT_UTMP if you didn't want any. Currently HAVE_PUTUTLINE is
56 * the only such symbol.
59 #if !defined HAVE_PUTUTLINE
60 #define HAVE_PUTUTLINE
64 typedef struct pty_tag
*Pty
;
67 * The pty_signal_pipe, along with the SIGCHLD handler, must be
68 * process-global rather than session-specific.
70 static int pty_signal_pipe
[2] = { -1, -1 }; /* obviously bogus initial val */
74 int master_fd
, slave_fd
;
76 char name
[FILENAME_MAX
];
78 int term_width
, term_height
;
79 int child_dead
, finished
;
84 * We store our pty backends in a tree sorted by master fd, so that
85 * when we get an uxsel notification we know which backend instance
86 * is the owner of the pty that caused it.
88 static int pty_compare_by_fd(void *av
, void *bv
)
93 if (a
->master_fd
< b
->master_fd
)
95 else if (a
->master_fd
> b
->master_fd
)
100 static int pty_find_by_fd(void *av
, void *bv
)
105 if (a
< b
->master_fd
)
107 else if (a
> b
->master_fd
)
112 static tree234
*ptys_by_fd
= NULL
;
115 * We also have a tree sorted by child pid, so that when we wait()
116 * in response to the signal we know which backend instance is the
117 * owner of the process that caused the signal.
119 static int pty_compare_by_pid(void *av
, void *bv
)
124 if (a
->child_pid
< b
->child_pid
)
126 else if (a
->child_pid
> b
->child_pid
)
131 static int pty_find_by_pid(void *av
, void *bv
)
136 if (a
< b
->child_pid
)
138 else if (a
> b
->child_pid
)
143 static tree234
*ptys_by_pid
= NULL
;
146 * If we are using pty_pre_init(), it will need to have already
147 * allocated a pty structure, which we must then return from
148 * pty_init() rather than allocating a new one. Here we store that
149 * structure between allocation and use.
151 * Note that although most of this module is entirely capable of
152 * handling multiple ptys in a single process, pty_pre_init() is
153 * fundamentally _dependent_ on there being at most one pty per
154 * process, so the normal static-data constraints don't apply.
156 * Likewise, since utmp is only used via pty_pre_init, it too must
157 * be single-instance, so we can declare utmp-related variables
160 static Pty single_pty
= NULL
;
163 static int pty_utmp_helper_pid
, pty_utmp_helper_pipe
;
164 static int pty_stamped_utmp
;
165 static struct utmp utmp_entry
;
169 * pty_argv is a grievous hack to allow a proper argv to be passed
170 * through from the Unix command line. Again, it doesn't really
171 * make sense outside a one-pty-per-process setup.
176 static void pty_close(Pty pty
);
179 static void setup_utmp(char *ttyname
, char *location
)
182 struct lastlog lastlog_entry
;
189 pw
= getpwuid(getuid());
190 memset(&utmp_entry
, 0, sizeof(utmp_entry
));
191 utmp_entry
.ut_type
= USER_PROCESS
;
192 utmp_entry
.ut_pid
= getpid();
193 strncpy(utmp_entry
.ut_line
, ttyname
+5, lenof(utmp_entry
.ut_line
));
194 strncpy(utmp_entry
.ut_id
, ttyname
+8, lenof(utmp_entry
.ut_id
));
195 strncpy(utmp_entry
.ut_user
, pw
->pw_name
, lenof(utmp_entry
.ut_user
));
196 strncpy(utmp_entry
.ut_host
, location
, lenof(utmp_entry
.ut_host
));
197 /* Apparently there are some architectures where (struct utmp).ut_time
198 * is not essentially time_t (e.g. Linux amd64). Hence the temporary. */
200 utmp_entry
.ut_time
= uttime
; /* may truncate */
202 #if defined HAVE_PUTUTLINE
205 pututline(&utmp_entry
);
209 if ((wtmp
= fopen(WTMP_FILE
, "a")) != NULL
) {
210 fwrite(&utmp_entry
, 1, sizeof(utmp_entry
), wtmp
);
215 memset(&lastlog_entry
, 0, sizeof(lastlog_entry
));
216 strncpy(lastlog_entry
.ll_line
, ttyname
+5, lenof(lastlog_entry
.ll_line
));
217 strncpy(lastlog_entry
.ll_host
, location
, lenof(lastlog_entry
.ll_host
));
218 time(&lastlog_entry
.ll_time
);
219 if ((lastlog
= fopen(LASTLOG_FILE
, "r+")) != NULL
) {
220 fseek(lastlog
, sizeof(lastlog_entry
) * getuid(), SEEK_SET
);
221 fwrite(&lastlog_entry
, 1, sizeof(lastlog_entry
), lastlog
);
226 pty_stamped_utmp
= 1;
230 static void cleanup_utmp(void)
235 if (!pty_stamped_utmp
)
238 utmp_entry
.ut_type
= DEAD_PROCESS
;
239 memset(utmp_entry
.ut_user
, 0, lenof(utmp_entry
.ut_user
));
241 utmp_entry
.ut_time
= uttime
;
243 if ((wtmp
= fopen(WTMP_FILE
, "a")) != NULL
) {
244 fwrite(&utmp_entry
, 1, sizeof(utmp_entry
), wtmp
);
248 memset(utmp_entry
.ut_line
, 0, lenof(utmp_entry
.ut_line
));
249 utmp_entry
.ut_time
= 0;
251 #if defined HAVE_PUTUTLINE
254 pututline(&utmp_entry
);
258 pty_stamped_utmp
= 0; /* ensure we never double-cleanup */
262 static void sigchld_handler(int signum
)
264 write(pty_signal_pipe
[1], "x", 1);
268 static void fatal_sig_handler(int signum
)
270 putty_signal(signum
, SIG_DFL
);
277 static int pty_open_slave(Pty pty
)
279 if (pty
->slave_fd
< 0)
280 pty
->slave_fd
= open(pty
->name
, O_RDWR
);
282 return pty
->slave_fd
;
285 static void pty_open_master(Pty pty
)
288 const char chars1
[] = "pqrstuvwxyz";
289 const char chars2
[] = "0123456789abcdef";
291 char master_name
[20];
294 for (p1
= chars1
; *p1
; p1
++)
295 for (p2
= chars2
; *p2
; p2
++) {
296 sprintf(master_name
, "/dev/pty%c%c", *p1
, *p2
);
297 pty
->master_fd
= open(master_name
, O_RDWR
);
298 if (pty
->master_fd
>= 0) {
299 if (geteuid() == 0 ||
300 access(master_name
, R_OK
| W_OK
) == 0) {
302 * We must also check at this point that we are
303 * able to open the slave side of the pty. We
304 * wouldn't want to allocate the wrong master,
305 * get all the way down to forking, and _then_
306 * find we're unable to open the slave.
308 strcpy(pty
->name
, master_name
);
309 pty
->name
[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */
311 if (pty_open_slave(pty
) >= 0 &&
312 access(pty
->name
, R_OK
| W_OK
) == 0)
314 if (pty
->slave_fd
> 0)
315 close(pty
->slave_fd
);
318 close(pty
->master_fd
);
322 /* If we get here, we couldn't get a tty at all. */
323 fprintf(stderr
, "pterm: unable to open a pseudo-terminal device\n");
328 /* We need to chown/chmod the /dev/ttyXX device. */
329 gp
= getgrnam("tty");
330 chown(pty
->name
, getuid(), gp ? gp
->gr_gid
: -1);
331 chmod(pty
->name
, 0600);
333 pty
->master_fd
= open("/dev/ptmx", O_RDWR
);
335 if (pty
->master_fd
< 0) {
336 perror("/dev/ptmx: open");
340 if (grantpt(pty
->master_fd
) < 0) {
345 if (unlockpt(pty
->master_fd
) < 0) {
350 pty
->name
[FILENAME_MAX
-1] = '\0';
351 strncpy(pty
->name
, ptsname(pty
->master_fd
), FILENAME_MAX
-1);
355 ptys_by_fd
= newtree234(pty_compare_by_fd
);
356 add234(ptys_by_fd
, pty
);
360 * Pre-initialisation. This is here to get around the fact that GTK
361 * doesn't like being run in setuid/setgid programs (probably
362 * sensibly). So before we initialise GTK - and therefore before we
363 * even process the command line - we check to see if we're running
364 * set[ug]id. If so, we open our pty master _now_, chown it as
365 * necessary, and drop privileges. We can always close it again
366 * later. If we're potentially going to be doing utmp as well, we
367 * also fork off a utmp helper process and communicate with it by
368 * means of a pipe; the utmp helper will keep privileges in order
369 * to clean up utmp when we exit (i.e. when its end of our pipe
372 void pty_pre_init(void)
381 pty
= single_pty
= snew(struct pty_tag
);
383 /* set the child signal handler straight away; it needs to be set
384 * before we ever fork. */
385 putty_signal(SIGCHLD
, sigchld_handler
);
386 pty
->master_fd
= pty
->slave_fd
= -1;
388 pty_stamped_utmp
= FALSE
;
391 if (geteuid() != getuid() || getegid() != getgid()) {
392 pty_open_master(pty
);
397 * Fork off the utmp helper.
399 if (pipe(pipefd
) < 0) {
400 perror("pterm: pipe");
405 perror("pterm: fork");
407 } else if (pid
== 0) {
408 char display
[128], buffer
[128];
413 * Now sit here until we receive a display name from the
414 * other end of the pipe, and then stamp utmp. Unstamp utmp
415 * again, and exit, when the pipe closes.
421 ret
= read(pipefd
[0], buffer
, lenof(buffer
));
425 } else if (!pty_stamped_utmp
) {
426 if (dlen
< lenof(display
))
427 memcpy(display
+dlen
, buffer
,
428 min(ret
, lenof(display
)-dlen
));
429 if (buffer
[ret
-1] == '\0') {
431 * Now we have a display name. NUL-terminate
432 * it, and stamp utmp.
434 display
[lenof(display
)-1] = '\0';
436 * Trap as many fatal signals as we can in the
437 * hope of having the best possible chance to
438 * clean up utmp before termination. We are
439 * unfortunately unprotected against SIGKILL,
442 putty_signal(SIGHUP
, fatal_sig_handler
);
443 putty_signal(SIGINT
, fatal_sig_handler
);
444 putty_signal(SIGQUIT
, fatal_sig_handler
);
445 putty_signal(SIGILL
, fatal_sig_handler
);
446 putty_signal(SIGABRT
, fatal_sig_handler
);
447 putty_signal(SIGFPE
, fatal_sig_handler
);
448 putty_signal(SIGPIPE
, fatal_sig_handler
);
449 putty_signal(SIGALRM
, fatal_sig_handler
);
450 putty_signal(SIGTERM
, fatal_sig_handler
);
451 putty_signal(SIGSEGV
, fatal_sig_handler
);
452 putty_signal(SIGUSR1
, fatal_sig_handler
);
453 putty_signal(SIGUSR2
, fatal_sig_handler
);
455 putty_signal(SIGBUS
, fatal_sig_handler
);
458 putty_signal(SIGPOLL
, fatal_sig_handler
);
461 putty_signal(SIGPROF
, fatal_sig_handler
);
464 putty_signal(SIGSYS
, fatal_sig_handler
);
467 putty_signal(SIGTRAP
, fatal_sig_handler
);
470 putty_signal(SIGVTALRM
, fatal_sig_handler
);
473 putty_signal(SIGXCPU
, fatal_sig_handler
);
476 putty_signal(SIGXFSZ
, fatal_sig_handler
);
479 putty_signal(SIGIO
, fatal_sig_handler
);
481 setup_utmp(pty
->name
, display
);
487 pty_utmp_helper_pid
= pid
;
488 pty_utmp_helper_pipe
= pipefd
[1];
494 #ifndef HAVE_NO_SETRESUID
495 int gid
= getgid(), uid
= getuid();
496 int setresgid(gid_t
, gid_t
, gid_t
);
497 int setresuid(uid_t
, uid_t
, uid_t
);
498 setresgid(gid
, gid
, gid
);
499 setresuid(uid
, uid
, uid
);
507 int pty_real_select_result(Pty pty
, int event
, int status
)
511 int finished
= FALSE
;
515 * We've been called because our child process did
516 * something. `status' tells us what.
518 if ((WIFEXITED(status
) || WIFSIGNALED(status
))) {
520 * The primary child process died. We could keep
521 * the terminal open for remaining subprocesses to
522 * output to, but conventional wisdom seems to feel
523 * that that's the Wrong Thing for an xterm-alike,
524 * so we bail out now (though we don't necessarily
525 * _close_ the window, depending on the state of
526 * Close On Exit). This would be easy enough to
527 * change or make configurable if necessary.
529 pty
->exit_code
= status
;
530 pty
->child_dead
= TRUE
;
531 del234(ptys_by_pid
, pty
);
537 ret
= read(pty
->master_fd
, buf
, sizeof(buf
));
540 * Clean termination condition is that either ret == 0, or ret
541 * < 0 and errno == EIO. Not sure why the latter, but it seems
544 if (ret
== 0 || (ret
< 0 && errno
== EIO
)) {
546 * We assume a clean exit if the pty has closed but the
547 * actual child process hasn't. The only way I can
548 * imagine this happening is if it detaches itself from
549 * the pty and goes daemonic - in which case the
550 * expected usage model would precisely _not_ be for
551 * the pterm window to hang around!
554 if (!pty
->child_dead
)
556 } else if (ret
< 0) {
557 perror("read pty master");
559 } else if (ret
> 0) {
560 from_backend(pty
->frontend
, 0, buf
, ret
);
565 if (finished
&& !pty
->finished
) {
566 uxsel_del(pty
->master_fd
);
570 pty
->finished
= TRUE
;
573 * This is a slight layering-violation sort of hack: only
574 * if we're not closing on exit (COE is set to Never, or to
575 * Only On Clean and it wasn't a clean exit) do we output a
576 * `terminated' message.
578 if (pty
->cfg
.close_on_exit
== FORCE_OFF
||
579 (pty
->cfg
.close_on_exit
== AUTO
&& pty
->exit_code
!= 0)) {
581 if (WIFEXITED(pty
->exit_code
))
582 sprintf(message
, "\r\n[pterm: process terminated with exit"
583 " code %d]\r\n", WEXITSTATUS(pty
->exit_code
));
584 else if (WIFSIGNALED(pty
->exit_code
))
585 #ifdef HAVE_NO_STRSIGNAL
586 sprintf(message
, "\r\n[pterm: process terminated on signal"
587 " %d]\r\n", WTERMSIG(pty
->exit_code
));
589 sprintf(message
, "\r\n[pterm: process terminated on signal"
590 " %d (%.400s)]\r\n", WTERMSIG(pty
->exit_code
),
591 strsignal(WTERMSIG(pty
->exit_code
)));
593 from_backend(pty
->frontend
, 0, message
, strlen(message
));
596 notify_remote_exit(pty
->frontend
);
602 int pty_select_result(int fd
, int event
)
607 if (fd
== pty_signal_pipe
[0]) {
613 read(pty_signal_pipe
[0], c
, 1); /* ignore its value; it'll be `x' */
616 pid
= waitpid(-1, &status
, WNOHANG
);
619 pty
= find234(ptys_by_pid
, &pid
, pty_find_by_pid
);
622 ret
= ret
&& pty_real_select_result(pty
, -1, status
);
625 pty
= find234(ptys_by_fd
, &fd
, pty_find_by_fd
);
628 ret
= ret
&& pty_real_select_result(pty
, event
, 0);
634 static void pty_uxsel_setup(Pty pty
)
636 uxsel_set(pty
->master_fd
, 1, pty_select_result
);
639 * In principle this only needs calling once for all pty
640 * backend instances, but it's simplest just to call it every
641 * time; uxsel won't mind.
643 uxsel_set(pty_signal_pipe
[0], 1, pty_select_result
);
647 * Called to set up the pty.
649 * Returns an error message, or NULL on success.
651 * Also places the canonical host name into `realhost'. It must be
652 * freed by the caller.
654 static const char *pty_init(void *frontend
, void **backend_handle
, Config
*cfg
,
655 char *host
, int port
, char **realhost
, int nodelay
,
660 #ifndef NOT_X_WINDOWS /* for Mac OS X native compilation */
668 pty
= snew(struct pty_tag
);
669 pty
->master_fd
= pty
->slave_fd
= -1;
671 pty_stamped_utmp
= FALSE
;
675 pty
->frontend
= frontend
;
676 *backend_handle
= NULL
; /* we can't sensibly use this, sadly */
678 pty
->cfg
= *cfg
; /* structure copy */
679 pty
->term_width
= cfg
->width
;
680 pty
->term_height
= cfg
->height
;
682 if (pty
->master_fd
< 0)
683 pty_open_master(pty
);
686 * Set the backspace character to be whichever of ^H and ^? is
687 * specified by bksp_is_delete.
690 struct termios attrs
;
691 tcgetattr(pty
->master_fd
, &attrs
);
692 attrs
.c_cc
[VERASE
] = cfg
->bksp_is_delete ?
'\177' : '\010';
693 tcsetattr(pty
->master_fd
, TCSANOW
, &attrs
);
698 * Stamp utmp (that is, tell the utmp helper process to do so),
701 if (!cfg
->stamp_utmp
) {
702 close(pty_utmp_helper_pipe
); /* just let the child process die */
703 pty_utmp_helper_pipe
= -1;
705 char *location
= get_x_display(pty
->frontend
);
706 int len
= strlen(location
)+1, pos
= 0; /* +1 to include NUL */
708 int ret
= write(pty_utmp_helper_pipe
, location
+pos
, len
- pos
);
710 perror("pterm: writing to utmp helper process");
711 close(pty_utmp_helper_pipe
); /* arrgh, just give up */
712 pty_utmp_helper_pipe
= -1;
720 #ifndef NOT_X_WINDOWS /* for Mac OS X native compilation */
721 windowid
= get_windowid(pty
->frontend
);
725 * Fork and execute the command.
739 slavefd
= pty_open_slave(pty
);
741 perror("slave pty: open");
745 close(pty
->master_fd
);
746 fcntl(slavefd
, F_SETFD
, 0); /* don't close on exec */
751 ioctl(slavefd
, TIOCSCTTY
, 1);
753 tcsetpgrp(slavefd
, pgrp
);
755 close(open(pty
->name
, O_WRONLY
, 0));
757 /* Close everything _else_, for tidiness. */
758 for (i
= 3; i
< 1024; i
++)
761 char term_env_var
[10 + sizeof(cfg
->termtype
)];
762 sprintf(term_env_var
, "TERM=%s", cfg
->termtype
);
763 putenv(term_env_var
);
765 #ifndef NOT_X_WINDOWS /* for Mac OS X native compilation */
767 char windowid_env_var
[40];
768 sprintf(windowid_env_var
, "WINDOWID=%ld", windowid
);
769 putenv(windowid_env_var
);
773 char *e
= cfg
->environmt
;
774 char *var
, *varend
, *val
, *varval
;
777 while (*e
&& *e
!= '\t') e
++;
784 varval
= dupprintf("%.*s=%s", varend
-var
, var
, val
);
787 * We must not free varval, since putenv links it
788 * into the environment _in place_. Weird, but
789 * there we go. Memory usage will be rationalised
790 * as soon as we exec anyway.
796 * SIGINT and SIGQUIT may have been set to ignored by our
797 * parent, particularly by things like sh -c 'pterm &' and
798 * some window managers. SIGCHLD, meanwhile, was blocked
799 * during pt_main() startup. Reverse all this for our child
802 putty_signal(SIGINT
, SIG_DFL
);
803 putty_signal(SIGQUIT
, SIG_DFL
);
804 block_signal(SIGCHLD
, 0);
806 execvp(pty_argv
[0], pty_argv
);
808 char *shell
= getenv("SHELL");
810 if (cfg
->login_shell
) {
811 char *p
= strrchr(shell
, '/');
812 shellname
= snewn(2+strlen(shell
), char);
814 sprintf(shellname
, "-%s", p
);
817 execl(getenv("SHELL"), shellname
, NULL
);
821 * If we're here, exec has gone badly foom.
826 pty
->child_pid
= pid
;
827 pty
->child_dead
= FALSE
;
828 pty
->finished
= FALSE
;
829 if (pty
->slave_fd
> 0)
830 close(pty
->slave_fd
);
832 ptys_by_pid
= newtree234(pty_compare_by_pid
);
833 add234(ptys_by_pid
, pty
);
836 if (pty_signal_pipe
[0] < 0 && pipe(pty_signal_pipe
) < 0) {
840 pty_uxsel_setup(pty
);
842 *backend_handle
= pty
;
847 static void pty_reconfig(void *handle
, Config
*cfg
)
849 Pty pty
= (Pty
)handle
;
851 * We don't have much need to reconfigure this backend, but
852 * unfortunately we do need to pick up the setting of Close On
853 * Exit so we know whether to give a `terminated' message.
855 pty
->cfg
= *cfg
; /* structure copy */
859 * Stub routine (never called in pterm).
861 static void pty_free(void *handle
)
863 Pty pty
= (Pty
)handle
;
865 /* Either of these may fail `not found'. That's fine with us. */
866 del234(ptys_by_pid
, pty
);
867 del234(ptys_by_fd
, pty
);
873 * Called to send data down the pty.
875 static int pty_send(void *handle
, char *buf
, int len
)
877 Pty pty
= (Pty
)handle
;
879 if (pty
->master_fd
< 0)
880 return 0; /* ignore all writes if fd closed */
883 int ret
= write(pty
->master_fd
, buf
, len
);
885 perror("write pty master");
894 static void pty_close(Pty pty
)
896 if (pty
->master_fd
>= 0) {
897 close(pty
->master_fd
);
901 if (pty_utmp_helper_pipe
>= 0) {
902 close(pty_utmp_helper_pipe
); /* this causes utmp to be cleaned up */
903 pty_utmp_helper_pipe
= -1;
909 * Called to query the current socket sendability status.
911 static int pty_sendbuffer(void *handle
)
913 /* Pty pty = (Pty)handle; */
918 * Called to set the size of the window
920 static void pty_size(void *handle
, int width
, int height
)
922 Pty pty
= (Pty
)handle
;
925 pty
->term_width
= width
;
926 pty
->term_height
= height
;
928 size
.ws_row
= (unsigned short)pty
->term_height
;
929 size
.ws_col
= (unsigned short)pty
->term_width
;
930 size
.ws_xpixel
= (unsigned short) pty
->term_width
*
931 font_dimension(pty
->frontend
, 0);
932 size
.ws_ypixel
= (unsigned short) pty
->term_height
*
933 font_dimension(pty
->frontend
, 1);
934 ioctl(pty
->master_fd
, TIOCSWINSZ
, (void *)&size
);
939 * Send special codes.
941 static void pty_special(void *handle
, Telnet_Special code
)
943 /* Pty pty = (Pty)handle; */
949 * Return a list of the special codes that make sense in this
952 static const struct telnet_special
*pty_get_specials(void *handle
)
954 /* Pty pty = (Pty)handle; */
956 * Hmm. When I get round to having this actually usable, it
957 * might be quite nice to have the ability to deliver a few
958 * well chosen signals to the child process - SIGINT, SIGTERM,
964 static Socket
pty_socket(void *handle
)
966 /* Pty pty = (Pty)handle; */
967 return NULL
; /* shouldn't ever be needed */
970 static int pty_sendok(void *handle
)
972 /* Pty pty = (Pty)handle; */
976 static void pty_unthrottle(void *handle
, int backlog
)
978 /* Pty pty = (Pty)handle; */
982 static int pty_ldisc(void *handle
, int option
)
984 /* Pty pty = (Pty)handle; */
985 return 0; /* neither editing nor echoing */
988 static void pty_provide_ldisc(void *handle
, void *ldisc
)
990 /* Pty pty = (Pty)handle; */
991 /* This is a stub. */
994 static void pty_provide_logctx(void *handle
, void *logctx
)
996 /* Pty pty = (Pty)handle; */
997 /* This is a stub. */
1000 static int pty_exitcode(void *handle
)
1002 Pty pty
= (Pty
)handle
;
1004 return -1; /* not dead yet */
1006 return pty
->exit_code
;
1009 static int pty_cfg_info(void *handle
)
1011 /* Pty pty = (Pty)handle; */
1015 Backend pty_backend
= {