2 #define _XOPEN_SOURCE_EXTENDED
16 #include <sys/types.h>
18 #include <sys/ioctl.h>
30 #define UTMP_FILE "/var/run/utmp"
33 #define WTMP_FILE "/var/log/wtmp"
37 #define LASTLOG_FILE _PATH_LASTLOG
39 #define LASTLOG_FILE "/var/log/lastlog"
44 * Set up a default for vaguely sane systems. The idea is that if
45 * OMIT_UTMP is not defined, then at least one of the symbols which
46 * enable particular forms of utmp processing should be, if only so
47 * that a link error can warn you that you should have defined
48 * OMIT_UTMP if you didn't want any. Currently HAVE_PUTUTLINE is
49 * the only such symbol.
52 #if !defined HAVE_PUTUTLINE
53 #define HAVE_PUTUTLINE
58 static char pty_name
[FILENAME_MAX
];
59 static int pty_stamped_utmp
= 0;
60 static int pty_child_pid
;
61 static int pty_utmp_helper_pid
, pty_utmp_helper_pipe
;
62 static sig_atomic_t pty_child_dead
;
64 static struct utmp utmp_entry
;
68 int pty_child_is_dead(void)
70 return pty_child_dead
;
73 static void pty_size(void);
75 static void setup_utmp(char *ttyname
, char *location
)
79 struct lastlog lastlog_entry
;
85 pw
= getpwuid(getuid());
86 memset(&utmp_entry
, 0, sizeof(utmp_entry
));
87 utmp_entry
.ut_type
= USER_PROCESS
;
88 utmp_entry
.ut_pid
= getpid();
89 strncpy(utmp_entry
.ut_line
, ttyname
+5, lenof(utmp_entry
.ut_line
));
90 strncpy(utmp_entry
.ut_id
, ttyname
+8, lenof(utmp_entry
.ut_id
));
91 strncpy(utmp_entry
.ut_user
, pw
->pw_name
, lenof(utmp_entry
.ut_user
));
92 strncpy(utmp_entry
.ut_host
, location
, lenof(utmp_entry
.ut_host
));
93 time(&utmp_entry
.ut_time
);
95 #if defined HAVE_PUTUTLINE
98 pututline(&utmp_entry
);
102 if ((wtmp
= fopen(WTMP_FILE
, "a")) != NULL
) {
103 fwrite(&utmp_entry
, 1, sizeof(utmp_entry
), wtmp
);
108 memset(&lastlog_entry
, 0, sizeof(lastlog_entry
));
109 strncpy(lastlog_entry
.ll_line
, ttyname
+5, lenof(lastlog_entry
.ll_line
));
110 strncpy(lastlog_entry
.ll_host
, location
, lenof(lastlog_entry
.ll_host
));
111 time(&lastlog_entry
.ll_time
);
112 if ((lastlog
= fopen(LASTLOG_FILE
, "r+")) != NULL
) {
113 fseek(lastlog
, sizeof(lastlog_entry
) * getuid(), SEEK_SET
);
114 fwrite(&lastlog_entry
, 1, sizeof(lastlog_entry
), lastlog
);
119 pty_stamped_utmp
= 1;
124 static void cleanup_utmp(void)
129 if (!pty_stamped_utmp
)
132 utmp_entry
.ut_type
= DEAD_PROCESS
;
133 memset(utmp_entry
.ut_user
, 0, lenof(utmp_entry
.ut_user
));
134 time(&utmp_entry
.ut_time
);
136 if ((wtmp
= fopen(WTMP_FILE
, "a")) != NULL
) {
137 fwrite(&utmp_entry
, 1, sizeof(utmp_entry
), wtmp
);
141 memset(utmp_entry
.ut_line
, 0, lenof(utmp_entry
.ut_line
));
142 utmp_entry
.ut_time
= 0;
144 #if defined HAVE_PUTUTLINE
147 pututline(&utmp_entry
);
151 pty_stamped_utmp
= 0; /* ensure we never double-cleanup */
155 static void sigchld_handler(int signum
)
159 pid
= waitpid(-1, &status
, WNOHANG
);
160 if (pid
== pty_child_pid
&& (WIFEXITED(status
) || WIFSIGNALED(status
)))
161 pty_child_dead
= TRUE
;
164 static void fatal_sig_handler(int signum
)
166 signal(signum
, SIG_DFL
);
172 static void pty_open_master(void)
175 const char chars1
[] = "pqrstuvwxyz";
176 const char chars2
[] = "0123456789abcdef";
178 char master_name
[20];
181 for (p1
= chars1
; *p1
; p1
++)
182 for (p2
= chars2
; *p2
; p2
++) {
183 sprintf(master_name
, "/dev/pty%c%c", *p1
, *p2
);
184 pty_master_fd
= open(master_name
, O_RDWR
);
185 if (pty_master_fd
>= 0) {
186 if (geteuid() == 0 ||
187 access(master_name
, R_OK
| W_OK
) == 0)
189 close(pty_master_fd
);
193 /* If we get here, we couldn't get a tty at all. */
194 fprintf(stderr
, "pterm: unable to open a pseudo-terminal device\n");
198 strcpy(pty_name
, master_name
);
199 pty_name
[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */
201 /* We need to chown/chmod the /dev/ttyXX device. */
202 gp
= getgrnam("tty");
203 chown(pty_name
, getuid(), gp ? gp
->gr_gid
: -1);
204 chmod(pty_name
, 0600);
206 pty_master_fd
= open("/dev/ptmx", O_RDWR
);
208 if (pty_master_fd
< 0) {
209 perror("/dev/ptmx: open");
213 if (grantpt(pty_master_fd
) < 0) {
218 if (unlockpt(pty_master_fd
) < 0) {
223 pty_name
[FILENAME_MAX
-1] = '\0';
224 strncpy(pty_name
, ptsname(pty_master_fd
), FILENAME_MAX
-1);
229 * Pre-initialisation. This is here to get around the fact that GTK
230 * doesn't like being run in setuid/setgid programs (probably
231 * sensibly). So before we initialise GTK - and therefore before we
232 * even process the command line - we check to see if we're running
233 * set[ug]id. If so, we open our pty master _now_, chown it as
234 * necessary, and drop privileges. We can always close it again
235 * later. If we're potentially going to be doing utmp as well, we
236 * also fork off a utmp helper process and communicate with it by
237 * means of a pipe; the utmp helper will keep privileges in order
238 * to clean up utmp when we exit (i.e. when its end of our pipe
241 void pty_pre_init(void)
248 if (geteuid() != getuid() || getegid() != getgid()) {
254 * Fork off the utmp helper.
256 if (pipe(pipefd
) < 0) {
257 perror("pterm: pipe");
262 perror("pterm: fork");
264 } else if (pid
== 0) {
265 char display
[128], buffer
[128];
270 * Now sit here until we receive a display name from the
271 * other end of the pipe, and then stamp utmp. Unstamp utmp
272 * again, and exit, when the pipe closes.
278 ret
= read(pipefd
[0], buffer
, lenof(buffer
));
282 } else if (!pty_stamped_utmp
) {
283 if (dlen
< lenof(display
))
284 memcpy(display
+dlen
, buffer
,
285 min(ret
, lenof(display
)-dlen
));
286 if (buffer
[ret
-1] == '\0') {
288 * Now we have a display name. NUL-terminate
289 * it, and stamp utmp.
291 display
[lenof(display
)-1] = '\0';
293 * Trap as many fatal signals as we can in the
294 * hope of having the best possible chance to
295 * clean up utmp before termination. We are
296 * unfortunately unprotected against SIGKILL,
299 signal(SIGHUP
, fatal_sig_handler
);
300 signal(SIGINT
, fatal_sig_handler
);
301 signal(SIGQUIT
, fatal_sig_handler
);
302 signal(SIGILL
, fatal_sig_handler
);
303 signal(SIGABRT
, fatal_sig_handler
);
304 signal(SIGFPE
, fatal_sig_handler
);
305 signal(SIGPIPE
, fatal_sig_handler
);
306 signal(SIGALRM
, fatal_sig_handler
);
307 signal(SIGTERM
, fatal_sig_handler
);
308 signal(SIGSEGV
, fatal_sig_handler
);
309 signal(SIGUSR1
, fatal_sig_handler
);
310 signal(SIGUSR2
, fatal_sig_handler
);
312 signal(SIGBUS
, fatal_sig_handler
);
315 signal(SIGPOLL
, fatal_sig_handler
);
318 signal(SIGPROF
, fatal_sig_handler
);
321 signal(SIGSYS
, fatal_sig_handler
);
324 signal(SIGTRAP
, fatal_sig_handler
);
327 signal(SIGVTALRM
, fatal_sig_handler
);
330 signal(SIGXCPU
, fatal_sig_handler
);
333 signal(SIGXFSZ
, fatal_sig_handler
);
336 signal(SIGIO
, fatal_sig_handler
);
338 /* Also clean up utmp on normal exit. */
339 atexit(cleanup_utmp
);
340 setup_utmp(pty_name
, display
);
346 pty_utmp_helper_pid
= pid
;
347 pty_utmp_helper_pipe
= pipefd
[1];
353 int gid
= getgid(), uid
= getuid();
354 #ifndef HAVE_NO_SETRESUID
355 int setresgid(gid_t
, gid_t
, gid_t
);
356 int setresuid(uid_t
, uid_t
, uid_t
);
357 setresgid(gid
, gid
, gid
);
358 setresuid(uid
, uid
, uid
);
367 * Called to set up the pty.
369 * Returns an error message, or NULL on success.
371 * Also places the canonical host name into `realhost'. It must be
372 * freed by the caller.
374 static char *pty_init(char *host
, int port
, char **realhost
, int nodelay
)
379 if (pty_master_fd
< 0)
383 * Set the backspace character to be whichever of ^H and ^? is
384 * specified by bksp_is_delete.
387 struct termios attrs
;
388 tcgetattr(pty_master_fd
, &attrs
);
389 attrs
.c_cc
[VERASE
] = cfg
.bksp_is_delete ?
'\177' : '\010';
390 tcsetattr(pty_master_fd
, TCSANOW
, &attrs
);
394 * Stamp utmp (that is, tell the utmp helper process to do so),
398 close(pty_utmp_helper_pipe
); /* just let the child process die */
400 char *location
= get_x_display();
401 int len
= strlen(location
)+1, pos
= 0; /* +1 to include NUL */
403 int ret
= write(pty_utmp_helper_pipe
, location
+pos
, len
- pos
);
405 perror("pterm: writing to utmp helper process");
406 close(pty_utmp_helper_pipe
); /* arrgh, just give up */
414 * Fork and execute the command.
428 slavefd
= open(pty_name
, O_RDWR
);
430 perror("slave pty: open");
434 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 execvp(pty_argv
[0], pty_argv
);
460 char *shell
= getenv("SHELL");
462 if (cfg
.login_shell
) {
463 char *p
= strrchr(shell
, '/');
464 shellname
= smalloc(2+strlen(shell
));
466 sprintf(shellname
, "-%s", p
);
469 execl(getenv("SHELL"), shellname
, NULL
);
473 * If we're here, exec has gone badly foom.
480 pty_child_dead
= FALSE
;
481 signal(SIGCHLD
, sigchld_handler
);
488 * Called to send data down the pty.
490 static int pty_send(char *buf
, int len
)
493 int ret
= write(pty_master_fd
, buf
, len
);
495 perror("write pty master");
505 * Called to query the current socket sendability status.
507 static int pty_sendbuffer(void)
513 * Called to set the size of the window
515 static void pty_size(void)
519 size
.ws_row
= (unsigned short)rows
;
520 size
.ws_col
= (unsigned short)cols
;
521 size
.ws_xpixel
= (unsigned short) cols
* font_dimension(0);
522 size
.ws_ypixel
= (unsigned short) rows
* font_dimension(1);
523 ioctl(pty_master_fd
, TIOCSWINSZ
, (void *)&size
);
528 * Send special codes.
530 static void pty_special(Telnet_Special code
)
536 static Socket
pty_socket(void)
538 return NULL
; /* shouldn't ever be needed */
541 static int pty_sendok(void)
546 static void pty_unthrottle(int backlog
)
551 static int pty_ldisc(int option
)
553 return 0; /* neither editing nor echoing */
556 static int pty_exitcode(void)
558 /* Shouldn't ever be required */
562 Backend pty_backend
= {