2 #define _XOPEN_SOURCE_EXTENDED
16 #include <sys/types.h>
18 #include <sys/ioctl.h>
31 #define UTMP_FILE "/var/run/utmp"
34 #define WTMP_FILE "/var/log/wtmp"
38 #define LASTLOG_FILE _PATH_LASTLOG
40 #define LASTLOG_FILE "/var/log/lastlog"
45 * Set up a default for vaguely sane systems. The idea is that if
46 * OMIT_UTMP is not defined, then at least one of the symbols which
47 * enable particular forms of utmp processing should be, if only so
48 * that a link error can warn you that you should have defined
49 * OMIT_UTMP if you didn't want any. Currently HAVE_PUTUTLINE is
50 * the only such symbol.
53 #if !defined HAVE_PUTUTLINE
54 #define HAVE_PUTUTLINE
59 static char pty_name
[FILENAME_MAX
];
60 static int pty_stamped_utmp
= 0;
61 static int pty_child_pid
;
62 static int pty_utmp_helper_pid
, pty_utmp_helper_pipe
;
63 static sig_atomic_t pty_child_dead
;
65 static struct utmp utmp_entry
;
69 int pty_child_is_dead(void)
71 return pty_child_dead
;
74 static void pty_size(void);
76 static void setup_utmp(char *ttyname
, char *location
)
80 struct lastlog lastlog_entry
;
86 pw
= getpwuid(getuid());
87 memset(&utmp_entry
, 0, sizeof(utmp_entry
));
88 utmp_entry
.ut_type
= USER_PROCESS
;
89 utmp_entry
.ut_pid
= getpid();
90 strncpy(utmp_entry
.ut_line
, ttyname
+5, lenof(utmp_entry
.ut_line
));
91 strncpy(utmp_entry
.ut_id
, ttyname
+8, lenof(utmp_entry
.ut_id
));
92 strncpy(utmp_entry
.ut_user
, pw
->pw_name
, lenof(utmp_entry
.ut_user
));
93 strncpy(utmp_entry
.ut_host
, location
, lenof(utmp_entry
.ut_host
));
94 time(&utmp_entry
.ut_time
);
96 #if defined HAVE_PUTUTLINE
99 pututline(&utmp_entry
);
103 if ((wtmp
= fopen(WTMP_FILE
, "a")) != NULL
) {
104 fwrite(&utmp_entry
, 1, sizeof(utmp_entry
), wtmp
);
109 memset(&lastlog_entry
, 0, sizeof(lastlog_entry
));
110 strncpy(lastlog_entry
.ll_line
, ttyname
+5, lenof(lastlog_entry
.ll_line
));
111 strncpy(lastlog_entry
.ll_host
, location
, lenof(lastlog_entry
.ll_host
));
112 time(&lastlog_entry
.ll_time
);
113 if ((lastlog
= fopen(LASTLOG_FILE
, "r+")) != NULL
) {
114 fseek(lastlog
, sizeof(lastlog_entry
) * getuid(), SEEK_SET
);
115 fwrite(&lastlog_entry
, 1, sizeof(lastlog_entry
), lastlog
);
120 pty_stamped_utmp
= 1;
125 static void cleanup_utmp(void)
130 if (!pty_stamped_utmp
)
133 utmp_entry
.ut_type
= DEAD_PROCESS
;
134 memset(utmp_entry
.ut_user
, 0, lenof(utmp_entry
.ut_user
));
135 time(&utmp_entry
.ut_time
);
137 if ((wtmp
= fopen(WTMP_FILE
, "a")) != NULL
) {
138 fwrite(&utmp_entry
, 1, sizeof(utmp_entry
), wtmp
);
142 memset(utmp_entry
.ut_line
, 0, lenof(utmp_entry
.ut_line
));
143 utmp_entry
.ut_time
= 0;
145 #if defined HAVE_PUTUTLINE
148 pututline(&utmp_entry
);
152 pty_stamped_utmp
= 0; /* ensure we never double-cleanup */
156 static void sigchld_handler(int signum
)
160 pid
= waitpid(-1, &status
, WNOHANG
);
161 if (pid
== pty_child_pid
&& (WIFEXITED(status
) || WIFSIGNALED(status
)))
162 pty_child_dead
= TRUE
;
165 static void fatal_sig_handler(int signum
)
167 signal(signum
, SIG_DFL
);
173 static void pty_open_master(void)
176 const char chars1
[] = "pqrstuvwxyz";
177 const char chars2
[] = "0123456789abcdef";
179 char master_name
[20];
182 for (p1
= chars1
; *p1
; p1
++)
183 for (p2
= chars2
; *p2
; p2
++) {
184 sprintf(master_name
, "/dev/pty%c%c", *p1
, *p2
);
185 pty_master_fd
= open(master_name
, O_RDWR
);
186 if (pty_master_fd
>= 0) {
187 if (geteuid() == 0 ||
188 access(master_name
, R_OK
| W_OK
) == 0)
190 close(pty_master_fd
);
194 /* If we get here, we couldn't get a tty at all. */
195 fprintf(stderr
, "pterm: unable to open a pseudo-terminal device\n");
199 strcpy(pty_name
, master_name
);
200 pty_name
[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */
202 /* We need to chown/chmod the /dev/ttyXX device. */
203 gp
= getgrnam("tty");
204 chown(pty_name
, getuid(), gp ? gp
->gr_gid
: -1);
205 chmod(pty_name
, 0600);
207 pty_master_fd
= open("/dev/ptmx", O_RDWR
);
209 if (pty_master_fd
< 0) {
210 perror("/dev/ptmx: open");
214 if (grantpt(pty_master_fd
) < 0) {
219 if (unlockpt(pty_master_fd
) < 0) {
224 pty_name
[FILENAME_MAX
-1] = '\0';
225 strncpy(pty_name
, ptsname(pty_master_fd
), FILENAME_MAX
-1);
230 * Pre-initialisation. This is here to get around the fact that GTK
231 * doesn't like being run in setuid/setgid programs (probably
232 * sensibly). So before we initialise GTK - and therefore before we
233 * even process the command line - we check to see if we're running
234 * set[ug]id. If so, we open our pty master _now_, chown it as
235 * necessary, and drop privileges. We can always close it again
236 * later. If we're potentially going to be doing utmp as well, we
237 * also fork off a utmp helper process and communicate with it by
238 * means of a pipe; the utmp helper will keep privileges in order
239 * to clean up utmp when we exit (i.e. when its end of our pipe
242 void pty_pre_init(void)
249 if (geteuid() != getuid() || getegid() != getgid()) {
255 * Fork off the utmp helper.
257 if (pipe(pipefd
) < 0) {
258 perror("pterm: pipe");
263 perror("pterm: fork");
265 } else if (pid
== 0) {
266 char display
[128], buffer
[128];
271 * Now sit here until we receive a display name from the
272 * other end of the pipe, and then stamp utmp. Unstamp utmp
273 * again, and exit, when the pipe closes.
279 ret
= read(pipefd
[0], buffer
, lenof(buffer
));
283 } else if (!pty_stamped_utmp
) {
284 if (dlen
< lenof(display
))
285 memcpy(display
+dlen
, buffer
,
286 min(ret
, lenof(display
)-dlen
));
287 if (buffer
[ret
-1] == '\0') {
289 * Now we have a display name. NUL-terminate
290 * it, and stamp utmp.
292 display
[lenof(display
)-1] = '\0';
294 * Trap as many fatal signals as we can in the
295 * hope of having the best possible chance to
296 * clean up utmp before termination. We are
297 * unfortunately unprotected against SIGKILL,
300 signal(SIGHUP
, fatal_sig_handler
);
301 signal(SIGINT
, fatal_sig_handler
);
302 signal(SIGQUIT
, fatal_sig_handler
);
303 signal(SIGILL
, fatal_sig_handler
);
304 signal(SIGABRT
, fatal_sig_handler
);
305 signal(SIGFPE
, fatal_sig_handler
);
306 signal(SIGPIPE
, fatal_sig_handler
);
307 signal(SIGALRM
, fatal_sig_handler
);
308 signal(SIGTERM
, fatal_sig_handler
);
309 signal(SIGSEGV
, fatal_sig_handler
);
310 signal(SIGUSR1
, fatal_sig_handler
);
311 signal(SIGUSR2
, fatal_sig_handler
);
313 signal(SIGBUS
, fatal_sig_handler
);
316 signal(SIGPOLL
, fatal_sig_handler
);
319 signal(SIGPROF
, fatal_sig_handler
);
322 signal(SIGSYS
, fatal_sig_handler
);
325 signal(SIGTRAP
, fatal_sig_handler
);
328 signal(SIGVTALRM
, fatal_sig_handler
);
331 signal(SIGXCPU
, fatal_sig_handler
);
334 signal(SIGXFSZ
, fatal_sig_handler
);
337 signal(SIGIO
, fatal_sig_handler
);
339 /* Also clean up utmp on normal exit. */
340 atexit(cleanup_utmp
);
341 setup_utmp(pty_name
, display
);
347 pty_utmp_helper_pid
= pid
;
348 pty_utmp_helper_pipe
= pipefd
[1];
349 signal(SIGCHLD
, sigchld_handler
);
355 int gid
= getgid(), uid
= getuid();
356 #ifndef HAVE_NO_SETRESUID
357 int setresgid(gid_t
, gid_t
, gid_t
);
358 int setresuid(uid_t
, uid_t
, uid_t
);
359 setresgid(gid
, gid
, gid
);
360 setresuid(uid
, uid
, uid
);
369 * Called to set up the pty.
371 * Returns an error message, or NULL on success.
373 * Also places the canonical host name into `realhost'. It must be
374 * freed by the caller.
376 static char *pty_init(void *frontend
,
377 char *host
, int port
, char **realhost
, int nodelay
)
382 if (pty_master_fd
< 0)
386 * Set the backspace character to be whichever of ^H and ^? is
387 * specified by bksp_is_delete.
390 struct termios attrs
;
391 tcgetattr(pty_master_fd
, &attrs
);
392 attrs
.c_cc
[VERASE
] = cfg
.bksp_is_delete ?
'\177' : '\010';
393 tcsetattr(pty_master_fd
, TCSANOW
, &attrs
);
397 * Stamp utmp (that is, tell the utmp helper process to do so),
401 close(pty_utmp_helper_pipe
); /* just let the child process die */
403 char *location
= get_x_display();
404 int len
= strlen(location
)+1, pos
= 0; /* +1 to include NUL */
406 int ret
= write(pty_utmp_helper_pipe
, location
+pos
, len
- pos
);
408 perror("pterm: writing to utmp helper process");
409 close(pty_utmp_helper_pipe
); /* arrgh, just give up */
417 * Fork and execute the command.
431 slavefd
= open(pty_name
, O_RDWR
);
433 perror("slave pty: open");
437 close(pty_master_fd
);
438 fcntl(slavefd
, F_SETFD
, 0); /* don't close on exec */
443 ioctl(slavefd
, TIOCSCTTY
, 1);
445 tcsetpgrp(slavefd
, pgrp
);
447 close(open(pty_name
, O_WRONLY
, 0));
449 /* Close everything _else_, for tidiness. */
450 for (i
= 3; i
< 1024; i
++)
453 char term_env_var
[10 + sizeof(cfg
.termtype
)];
454 sprintf(term_env_var
, "TERM=%s", cfg
.termtype
);
455 putenv(term_env_var
);
458 * SIGINT and SIGQUIT may have been set to ignored by our
459 * parent, particularly by things like sh -c 'pterm &' and
460 * some window managers. Reverse this for our child process.
462 signal(SIGINT
, SIG_DFL
);
463 signal(SIGQUIT
, SIG_DFL
);
465 execvp(pty_argv
[0], pty_argv
);
467 char *shell
= getenv("SHELL");
469 if (cfg
.login_shell
) {
470 char *p
= strrchr(shell
, '/');
471 shellname
= smalloc(2+strlen(shell
));
473 sprintf(shellname
, "-%s", p
);
476 execl(getenv("SHELL"), shellname
, NULL
);
480 * If we're here, exec has gone badly foom.
487 pty_child_dead
= FALSE
;
488 signal(SIGCHLD
, sigchld_handler
);
495 * Called to send data down the pty.
497 static int pty_send(char *buf
, int len
)
500 int ret
= write(pty_master_fd
, buf
, len
);
502 perror("write pty master");
512 * Called to query the current socket sendability status.
514 static int pty_sendbuffer(void)
520 * Called to set the size of the window
522 static void pty_size(void)
526 size
.ws_row
= (unsigned short)term
->rows
;
527 size
.ws_col
= (unsigned short)term
->cols
;
528 size
.ws_xpixel
= (unsigned short) term
->cols
* font_dimension(0);
529 size
.ws_ypixel
= (unsigned short) term
->rows
* font_dimension(1);
530 ioctl(pty_master_fd
, TIOCSWINSZ
, (void *)&size
);
535 * Send special codes.
537 static void pty_special(Telnet_Special code
)
543 static Socket
pty_socket(void)
545 return NULL
; /* shouldn't ever be needed */
548 static int pty_sendok(void)
553 static void pty_unthrottle(int backlog
)
558 static int pty_ldisc(int option
)
560 return 0; /* neither editing nor echoing */
563 static int pty_exitcode(void)
565 /* Shouldn't ever be required */
569 Backend pty_backend
= {