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Comparing libptytty/src/ptytty.C (file contents):
Revision 1.21 by root, Mon Jan 23 11:53:27 2006 UTC vs.
Revision 1.43 by sf-exg, Sun Nov 20 14:38:44 2011 UTC

… …
5 * File: ptytty.C 5 * File: ptytty.C
6 *----------------------------------------------------------------------* 6 *----------------------------------------------------------------------*
7 * 7 *
8 * All portions of code are copyright by their respective author/s. 8 * All portions of code are copyright by their respective author/s.
9 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com> 9 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com>
10 * Copyright (c) 2004-2006 Marc Lehmann <pcg@goof.com> 10 * Copyright (c) 2004-2006 Marc Lehmann <schmorp@schmorp.de>
11 * Copyright (c) 2006 Emanuele Giaquinta <e.giaquinta@glauco.it> 11 * Copyright (c) 2006 Emanuele Giaquinta <e.giaquinta@glauco.it>
12 * 12 *
13 * This program is free software; you can redistribute it and/or modify 13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by 14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or 15 * the Free Software Foundation; either version 2 of the License, or
… …
23 * You should have received a copy of the GNU General Public License 23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software 24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 *---------------------------------------------------------------------*/ 26 *---------------------------------------------------------------------*/
27 27
28#include "../config.h" 28#include "config.h"
29 29
30#include "ptytty.h" 30#include "ptytty.h"
31 31
32#include <cstdlib> 32#include <cstdlib>
33#include <cstring> 33#include <cstring>
34#include <csignal> 34#include <csignal>
35 35
36#include <sys/types.h> 36#include <sys/types.h>
37#include <sys/socket.h> 37#include <sys/stat.h>
38#include <unistd.h> 38#include <unistd.h>
39#include <fcntl.h> 39#include <fcntl.h>
40 40
41#ifdef HAVE_SYS_IOCTL_H 41#ifdef HAVE_SYS_IOCTL_H
42# include <sys/ioctl.h> 42# include <sys/ioctl.h>
43#endif 43#endif
44#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H) 44#if defined(HAVE_SYS_STROPTS_H)
45# include <sys/stropts.h> /* for I_PUSH */ 45# include <sys/stropts.h> /* for I_PUSH */
46#endif 46#endif
47#ifdef HAVE_ISASTREAM 47#if defined(HAVE_ISASTREAM) && defined(HAVE_STROPTS_H)
48# include <stropts.h> 48# include <stropts.h>
49#endif 49#endif
50#if defined(HAVE_PTY_H) 50#if defined(HAVE_PTY_H)
51# include <pty.h> 51# include <pty.h>
52#elif defined(HAVE_LIBUTIL_H) 52#elif defined(HAVE_LIBUTIL_H)
… …
64 64
65/* ------------------------------------------------------------------------- * 65/* ------------------------------------------------------------------------- *
66 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 66 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
67 * ------------------------------------------------------------------------- */ 67 * ------------------------------------------------------------------------- */
68/* 68/*
69 * Returns pty file descriptor, or -1 on failure 69 * Returns pty file descriptor, or -1 on failure
70 * If successful, ttydev is set to the name of the slave device. 70 * If successful, ttydev is set to the name of the slave device.
71 * fd_tty _may_ also be set to an open fd to the slave device 71 * fd_tty _may_ also be set to an open fd to the slave device
72 */ 72 */
73#if defined(UNIX98_PTY) 73#if defined(UNIX98_PTY)
74
74static int 75 static int
75get_pty (int *fd_tty, char **ttydev) 76 get_pty (int *fd_tty, char **ttydev)
76{ 77 {
77 int pfd; 78 int pfd;
78 79
79# if defined(HAVE_GETPT) 80# if defined(HAVE_GETPT)
80 pfd = getpt(); 81 pfd = getpt ();
81# elif defined(HAVE_POSIX_OPENPT) 82# elif defined(HAVE_POSIX_OPENPT)
82 pfd = posix_openpt (O_RDWR); 83 pfd = posix_openpt (O_RDWR | O_NOCTTY);
83# else 84# else
85# ifdef _AIX
84 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); 86 pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0);
87# else
88 pfd = open ("/dev/ptmx", O_RDWR | O_NOCTTY, 0);
89# endif
85# endif 90# endif
91
86 if (pfd >= 0) 92 if (pfd >= 0)
87 { 93 {
88 if (grantpt (pfd) == 0 /* change slave permissions */ 94 if (grantpt (pfd) == 0 /* change slave permissions */
89 && unlockpt (pfd) == 0) 95 && unlockpt (pfd) == 0)
96 {
90 { /* slave now unlocked */ 97 /* slave now unlocked */
91 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 98 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
92 return pfd; 99 return pfd;
93 } 100 }
94 101
95 close (pfd); 102 close (pfd);
96 } 103 }
97 104
98 return -1; 105 return -1;
99} 106 }
107
100#elif defined(HAVE_OPENPTY) 108#elif defined(HAVE_OPENPTY)
109
101static int 110 static int
102get_pty (int *fd_tty, char **ttydev) 111 get_pty (int *fd_tty, char **ttydev)
103{ 112 {
104 int pfd; 113 int pfd;
105 int res; 114 int res;
106 char tty_name[32]; 115
107
108 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 116 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
117
109 if (res != -1) 118 if (res != -1)
110 { 119 {
111 *ttydev = strdup (tty_name); 120 *ttydev = strdup (ttyname (*fd_tty));
112 return pfd; 121 return pfd;
113 } 122 }
114 123
115 return -1; 124 return -1;
116} 125 }
126
117#elif defined(HAVE__GETPTY) 127#elif defined(HAVE__GETPTY)
128
118static int 129 static int
119get_pty (int *fd_tty, char **ttydev) 130 get_pty (int *fd_tty, char **ttydev)
120{ 131 {
121 int pfd; 132 int pfd;
133 char *slave;
122 134
123 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 135 slave = _getpty (&pfd, O_RDWR | O_NOCTTY, 0622, 0);
124 if (*ttydev != NULL)
125 return pfd;
126 136
127 return -1; 137 if (slave != NULL)
128}
129#elif defined(HAVE_DEV_PTC)
130static int
131get_pty (int *fd_tty, char **ttydev)
132{
133 int pfd;
134
135 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
136 { 138 {
137 *ttydev = strdup (ttyname (pfd)); 139 *ttydev = strdup (slave);
138 return pfd; 140 return pfd;
139 } 141 }
140 142
141 return -1; 143 return -1;
142}
143#elif defined(HAVE_DEV_CLONE)
144static int
145get_pty (int *fd_tty, char **ttydev)
146{
147 int pfd;
148
149 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0)
150 {
151 *ttydev = strdup (ptsname (pfd));
152 return pfd;
153 } 144 }
154 145
155 return -1;
156}
157#else 146#else
147
158/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 148 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
159static int 149 static int
160get_pty (int *fd_tty, char **ttydev) 150 get_pty (int *fd_tty, char **ttydev)
161{ 151 {
162 int pfd; 152 int pfd;
163 int i; 153 int i;
164 char pty_name[32]; 154 char pty_name[32];
165 char tty_name[32]; 155 char tty_name[32];
166 const char *majors = "pqrstuvwxyzabcde"; 156 const char *majors = "pqrstuvwxyzabcde";
167 const char *minors = "0123456789abcdef"; 157 const char *minors = "0123456789abcdef";
158
168 for (i = 0; i < 256; i++) 159 for (i = 0; i < 256; i++)
169 { 160 {
170 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]); 161 snprintf (pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]);
171 snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]); 162 snprintf (tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]);
163
172 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 164 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
173 { 165 {
174 snprintf(pty_name, 32, "/dev/ptyp%d", i); 166 snprintf (pty_name, 32, "/dev/ptyp%d", i);
175 snprintf(tty_name, 32, "/dev/ttyp%d", i); 167 snprintf (tty_name, 32, "/dev/ttyp%d", i);
176 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 168 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
177 continue; 169 continue;
178 } 170 }
171
179 if (access (tty_name, R_OK | W_OK) == 0) 172 if (access (tty_name, R_OK | W_OK) == 0)
180 { 173 {
181 *ttydev = strdup (tty_name); 174 *ttydev = strdup (tty_name);
182 return pfd; 175 return pfd;
183 } 176 }
184 177
185 close (pfd); 178 close (pfd);
186 } 179 }
187} 180
181 return -1;
182 }
183
188#endif 184#endif
189 185
190/*----------------------------------------------------------------------*/ 186/*----------------------------------------------------------------------*/
191/* 187/*
192 * Returns tty file descriptor, or -1 on failure 188 * Returns tty file descriptor, or -1 on failure
193 */ 189 */
194static int 190static int
195get_tty (char *ttydev) 191get_tty (char *ttydev)
196{ 192{
197 return open (ttydev, O_RDWR | O_NOCTTY, 0); 193 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
202 * Make our tty a controlling tty so that /dev/tty points to us 198 * Make our tty a controlling tty so that /dev/tty points to us
203 */ 199 */
204static int 200static int
205control_tty (int fd_tty) 201control_tty (int fd_tty)
206{ 202{
203 int fd;
204
207 setsid (); 205 setsid ();
208 206
209#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 207#ifdef TIOCSCTTY
208 ioctl (fd_tty, TIOCSCTTY, NULL);
209#else
210 fd = open (ttyname (fd_tty), O_RDWR);
211 if (fd >= 0)
212 close (fd);
213#endif
214
215 fd = open ("/dev/tty", O_WRONLY);
216 if (fd < 0)
217 return -1; /* fatal */
218
219 close (fd);
220
221 return 0;
222}
223
224void
225ptytty::close_tty ()
226{
227 if (tty < 0)
228 return;
229
230 close (tty);
231 tty = -1;
232}
233
234bool
235ptytty::make_controlling_tty ()
236{
237 return control_tty (tty) >= 0;
238}
239
240void
241ptytty::set_utf8_mode (bool on)
242{
243#ifdef IUTF8
244 if (pty < 0)
245 return;
246
247 struct termios tio;
248
249 if (tcgetattr (pty, &tio) != -1)
250 {
251 tcflag_t new_cflag = tio.c_iflag;
252
253 if (on)
254 new_cflag |= IUTF8;
255 else
256 new_cflag &= ~IUTF8;
257
258 if (new_cflag != tio.c_iflag)
259 {
260 tio.c_iflag = new_cflag;
261 tcsetattr (pty, TCSANOW, &tio);
262 }
263 }
264#endif
265}
266
267static struct ttyconf {
268 gid_t gid;
269 mode_t mode;
270
271 ttyconf ()
272 {
273#ifdef TTY_GID_SUPPORT
274 struct group *gr = getgrnam ("tty");
275
276 if (gr)
277 {
278 /* change group ownership of tty to "tty" */
279 mode = S_IRUSR | S_IWUSR | S_IWGRP;
280 gid = gr->gr_gid;
281 }
282 else
283#endif /* TTY_GID_SUPPORT */
284 {
285 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
286 gid = 0;
287 }
288 }
289} ttyconf;
290
291ptytty_unix::ptytty_unix ()
292{
293 name = 0;
294#if UTMP_SUPPORT
295 cmd_pid = 0;
296#endif
297}
298
299ptytty_unix::~ptytty_unix ()
300{
301#if UTMP_SUPPORT
302 logout ();
303#endif
304 put ();
305}
306
307void
308ptytty_unix::put ()
309{
310 if (name)
311 {
312 chmod (name, RESTORE_TTY_MODE);
313 chown (name, 0, ttyconf.gid);
314 }
315
316 close_tty ();
317
318 if (pty >= 0)
319 close (pty);
320
321 free (name);
322
323 pty = tty = -1;
324 name = 0;
325}
326
327bool
328ptytty_unix::get ()
329{
330 /* get master (pty) */
331 if ((pty = get_pty (&tty, &name)) < 0)
332 return false;
333
334 fcntl (pty, F_SETFL, O_NONBLOCK);
335
336 /* get slave (tty) */
337 if (tty < 0)
338 {
339#ifndef NO_SETOWNER_TTYDEV
340 chown (name, getuid (), ttyconf.gid); /* fail silently */
341 chmod (name, ttyconf.mode);
342# ifdef HAVE_REVOKE
343 revoke (name);
344# endif
345#endif
346
347 if ((tty = get_tty (name)) < 0)
348 {
349 put ();
350 return false;
351 }
352 }
353
354#if defined(I_PUSH)
210 /* 355 /*
211 * Push STREAMS modules: 356 * Push STREAMS modules:
212 * ptem: pseudo-terminal hardware emulation module. 357 * ptem: pseudo-terminal hardware emulation module.
213 * ldterm: standard terminal line discipline. 358 * ldterm: standard terminal line discipline.
214 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module. 359 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module.
215 * 360 *
216 * After we push the STREAMS modules, the first open () on the slave side 361 * After we push the STREAMS modules, the first open () on the slave side
217 * (i.e. the next section between the dashes giving us "tty opened OK")
218 * should make the "ptem" (or "ldterm" depending upon either which OS 362 * should make the "ptem" (or "ldterm" depending upon either which OS
219 * version or which set of manual pages you have) module give us a 363 * version or which set of manual pages you have) module give us a
220 * controlling terminal. We must already have close ()d the master side 364 * controlling terminal. We must already have close ()d the master side
221 * fd in this child process before we push STREAMS modules on because the 365 * fd in this child process before we push STREAMS modules on because the
222 * documentation is really unclear about whether it is any close () on 366 * documentation is really unclear about whether it is any close () on
223 * the master side or the last close () - i.e. a proper STREAMS dismantling 367 * the master side or the last close () - i.e. a proper STREAMS dismantling
224 * close () - on the master side which causes a hang up to be sent 368 * close () - on the master side which causes a hang up to be sent
225 * through - Geoff Wing 369 * through - Geoff Wing
226 */ 370 */
227# ifdef HAVE_ISASTREAM 371#if defined(HAVE_ISASTREAM) && defined(HAVE_STROPTS_H)
228 if (isastream (fd_tty) == 1) 372 if (isastream (tty) == 1)
229# endif 373# endif
230 { 374 {
231 ioctl (fd_tty, I_PUSH, "ptem"); 375 ioctl (tty, I_PUSH, "ptem");
232 ioctl (fd_tty, I_PUSH, "ldterm"); 376 ioctl (tty, I_PUSH, "ldterm");
233 ioctl (fd_tty, I_PUSH, "ttcompat"); 377 ioctl (tty, I_PUSH, "ttcompat");
234 }
235#endif
236
237 ioctl (fd_tty, TIOCSCTTY, NULL);
238
239 int fd = open ("/dev/tty", O_WRONLY);
240 if (fd < 0)
241 return -1; /* fatal */
242
243 close (fd);
244
245 return 0;
246}
247
248void
249ptytty::close_tty ()
250{
251 if (tty < 0)
252 return;
253
254 close (tty);
255 tty = -1;
256}
257
258bool
259ptytty::make_controlling_tty ()
260{
261 return control_tty (tty) >= 0;
262}
263
264void
265ptytty::set_utf8_mode (bool on)
266{
267#ifdef IUTF8
268 if (pty < 0)
269 return;
270
271 struct termios tio;
272
273 if (tcgetattr (pty, &tio) != -1)
274 { 378 }
275 tcflag_t new_cflag = tio.c_iflag;
276
277 if (on)
278 new_cflag |= IUTF8;
279 else
280 new_cflag &= ~IUTF8;
281
282 if (new_cflag != tio.c_iflag)
283 {
284 tio.c_iflag = new_cflag;
285 tcsetattr (pty, TCSANOW, &tio);
286 }
287 }
288#endif
289}
290
291static struct ttyconf {
292 gid_t gid;
293 mode_t mode;
294
295 ttyconf ()
296 {
297#ifdef TTY_GID_SUPPORT
298 struct group *gr = getgrnam ("tty");
299
300 if (gr)
301 { /* change group ownership of tty to "tty" */
302 mode = S_IRUSR | S_IWUSR | S_IWGRP;
303 gid = gr->gr_gid;
304 }
305 else
306#endif /* TTY_GID_SUPPORT */
307 {
308 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
309 gid = 0;
310 }
311 }
312} ttyconf;
313
314ptytty_unix::ptytty_unix ()
315{
316 name = 0;
317#if UTMP_SUPPORT
318 cmd_pid = 0;
319#endif
320}
321
322ptytty_unix::~ptytty_unix ()
323{
324#if UTMP_SUPPORT
325 logout ();
326#endif
327 put ();
328}
329
330void
331ptytty_unix::put ()
332{
333 chmod (name, RESTORE_TTY_MODE);
334 chown (name, 0, ttyconf.gid);
335
336 close_tty ();
337
338 if (pty >= 0)
339 close (pty);
340
341 free (name);
342
343 pty = tty = -1;
344 name = 0;
345}
346
347bool
348ptytty_unix::get ()
349{
350 /* get master (pty) */
351 if ((pty = get_pty (&tty, &name)) < 0)
352 return false;
353
354 fcntl (pty, F_SETFL, O_NONBLOCK);
355
356 /* get slave (tty) */
357 if (tty < 0)
358 {
359#ifndef NO_SETOWNER_TTYDEV
360 chown (name, getuid (), ttyconf.gid); /* fail silently */
361 chmod (name, ttyconf.mode);
362# ifdef HAVE_REVOKE
363 revoke (name);
364# endif 379#endif
365#endif
366
367 if ((tty = get_tty (name)) < 0)
368 {
369 put ();
370 return false;
371 }
372 }
373 380
374 return true; 381 return true;
375} 382}
376 383
377/////////////////////////////////////////////////////////////////////////////
378// helper/proxy support
379
380#if PTYTTY_HELPER
381
382static int sock_fd = -1, lock_fd = -1;
383static int helper_pid, owner_pid;
384
385struct command
386{
387 enum { get, login, destroy } type;
388
389 ptytty *id;
390
391 bool login_shell;
392 int cmd_pid;
393 char hostname[512]; // arbitrary, but should be plenty
394};
395
396struct ptytty_proxy : ptytty
397{
398 ptytty *id;
399
400 ptytty_proxy ()
401 : id(0)
402 {
403 }
404
405 ~ptytty_proxy ();
406
407 bool get ();
408 void login (int cmd_pid, bool login_shell, const char *hostname);
409};
410
411#if PTYTTY_REENTRANT
412# define NEED_TOKEN do { char ch; read (lock_fd, &ch, 1); } while (0)
413# define GIVE_TOKEN do { char ch; write (lock_fd, &ch, 1); } while (0)
414#else
415# define NEED_TOKEN (void)0
416# define GIVE_TOKEN (void)0
417#endif
418
419bool
420ptytty_proxy::get ()
421{
422 NEED_TOKEN;
423
424 command cmd;
425
426 cmd.type = command::get;
427
428 write (sock_fd, &cmd, sizeof (cmd));
429
430 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
431 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
432
433 if (!id)
434 {
435 GIVE_TOKEN;
436 return false;
437 }
438
439 if ((pty = recv_fd (sock_fd)) < 0
440 || (tty = recv_fd (sock_fd)) < 0)
441 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
442
443 GIVE_TOKEN;
444 return true;
445}
446
447void
448ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
449{
450 NEED_TOKEN;
451
452 command cmd;
453
454 cmd.type = command::login;
455 cmd.id = id;
456 cmd.cmd_pid = cmd_pid;
457 cmd.login_shell = login_shell;
458 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
459
460 write (sock_fd, &cmd, sizeof (cmd));
461
462 GIVE_TOKEN;
463}
464
465ptytty_proxy::~ptytty_proxy ()
466{
467 if (id)
468 {
469 NEED_TOKEN;
470
471 command cmd;
472
473 cmd.type = command::destroy;
474 cmd.id = id;
475
476 write (sock_fd, &cmd, sizeof (cmd));
477
478 GIVE_TOKEN;
479 }
480}
481
482static
483void serve ()
484{
485 command cmd;
486 vector<ptytty *> ptys;
487
488 for (;;)
489 {
490 GIVE_TOKEN;
491
492 if (read (sock_fd, &cmd, sizeof (command)) != sizeof (command))
493 break;
494
495 if (cmd.type == command::get)
496 {
497 // -> id ptyfd ttyfd
498 cmd.id = new ptytty_unix;
499
500 if (cmd.id->get ())
501 {
502 write (sock_fd, &cmd.id, sizeof (cmd.id));
503 ptys.push_back (cmd.id);
504
505 ptytty::send_fd (sock_fd, cmd.id->pty);
506 ptytty::send_fd (sock_fd, cmd.id->tty);
507 }
508 else
509 {
510 delete cmd.id;
511 cmd.id = 0;
512 write (sock_fd, &cmd.id, sizeof (cmd.id));
513 }
514 }
515 else if (cmd.type == command::login)
516 {
517#if UTMP_SUPPORT
518 if (find (ptys.begin (), ptys.end (), cmd.id) != ptys.end ())
519 {
520 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
521 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
522 }
523#endif
524 }
525 else if (cmd.type == command::destroy)
526 {
527 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
528
529 if (pty != ptys.end ())
530 {
531 delete *pty;
532 ptys.erase (pty);
533 }
534 }
535 else
536 break;
537
538 NEED_TOKEN;
539 }
540
541 // destroy all ptys
542 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
543 delete *i;
544}
545
546void
547ptytty::use_helper ()
548{
549#ifndef PTYTTY_NO_PID_CHECK
550 int pid = getpid ();
551#endif
552
553 if (sock_fd >= 0
554#ifndef PTYTTY_NO_PID_CHECK
555 && pid == owner_pid
556#endif
557 )
558 return;
559
560#ifndef PTYTTY_NO_PID_CHECK
561 owner_pid = pid;
562#endif
563
564 int sv[2];
565
566 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
567 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
568
569#ifdef PTYTTY_REENTRANT
570 int lv[2];
571
572 if (socketpair (AF_UNIX, SOCK_STREAM, 0, lv))
573 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
574#endif
575
576 helper_pid = fork ();
577
578 if (helper_pid < 0)
579 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
580
581 if (helper_pid)
582 {
583 // client, process
584 sock_fd = sv[0];
585 close (sv[1]);
586 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
587#ifdef PTYTTY_REENTRANT
588 lock_fd = lv[0];
589 close (lv[1]);
590 fcntl (lock_fd, F_SETFD, FD_CLOEXEC);
591#endif
592 }
593 else
594 {
595 // server, pty-helper
596 sock_fd = sv[1];
597#ifdef PTYTTY_REENTRANT
598 lock_fd = lv[1];
599#endif
600
601 chdir ("/");
602
603 signal (SIGHUP, SIG_IGN);
604 signal (SIGTERM, SIG_IGN);
605 signal (SIGINT, SIG_IGN);
606 signal (SIGPIPE, SIG_IGN);
607
608 for (int fd = 0; fd < 1023; fd++)
609 if (fd != sock_fd && fd != lock_fd)
610 close (fd);
611
612 serve ();
613 _exit (EXIT_SUCCESS);
614 }
615}
616
617#endif
618
619ptytty *
620ptytty::create ()
621{
622#if PTYTTY_HELPER
623 if (helper_pid
624# ifndef PTYTTY_NO_PID_CHECK
625 && getpid () == owner_pid
626# endif
627 )
628 // use helper process
629 return new ptytty_proxy;
630 else
631#endif
632 return new ptytty_unix;
633}
634
635void
636ptytty::init ()
637{
638 uid_t uid = getuid ();
639 gid_t gid = getgid ();
640
641 // before doing anything else, check for setuid/setgid operation,
642 // start the helper process and drop privileges
643 if (uid != geteuid ()
644 || gid != getegid ())
645 {
646#if PTYTTY_HELPER
647 use_helper ();
648#else
649 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
650#endif
651
652 drop_privileges ();
653 }
654}
655
656void
657ptytty::drop_privileges ()
658{
659 uid_t uid = getuid ();
660 gid_t gid = getgid ();
661
662 // drop privileges
663#if HAVE_SETRESUID
664 setresgid (gid, gid, gid);
665 setresuid (uid, uid, uid);
666#elif HAVE_SETREUID
667 setregid (gid, gid);
668 setreuid (uid, uid);
669#elif HAVE_SETUID
670 setgid (gid);
671 setuid (uid);
672#endif
673
674 if (uid != geteuid ()
675 || gid != getegid ())
676 ptytty_fatal ("unable to drop privileges, aborting.\n");
677}
678
679/////////////////////////////////////////////////////////////////////////////
680// C API
681
682#ifndef PTYTTY_NO_C_API
683
684#define DEFINE_METHOD(retval, name, args1, args2) \
685extern "C" retval ptytty_ ## name args1 \
686{ return ((struct ptytty *)ptytty)->name args2; }
687
688DEFINE_METHOD(int,pty,(void *ptytty),)
689DEFINE_METHOD(int,tty,(void *ptytty),)
690DEFINE_METHOD(int,get,(void *ptytty),())
691DEFINE_METHOD(void,login,(void *ptytty, int cmd_pid, bool login_shell, const char *hostname),(cmd_pid,login_shell,hostname))
692
693DEFINE_METHOD(void,close_tty,(void *ptytty),())
694DEFINE_METHOD(int,make_controlling_tty,(void *ptytty),())
695DEFINE_METHOD(void,set_utf8_mode,(void *ptytty, int on),(on))
696
697#define DEFINE_STATIC(retval, name, args) \
698extern "C" retval ptytty_ ## name args \
699{ return ptytty::name args; }
700
701DEFINE_STATIC(void,drop_privileges,())
702DEFINE_STATIC(void,use_helper,())
703DEFINE_STATIC(void,init,())
704
705DEFINE_STATIC(void *,create,())
706
707void ptytty_delete (void *ptytty)
708{
709 delete (struct ptytty *)ptytty;
710}
711
712// send_fd, recv_fd not exposed
713
714#endif

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