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Revision 1.15 by root, Mon Jan 23 11:22:08 2006 UTC vs.
Revision 1.50 by sf-exg, Thu Jan 19 11:06:10 2012 UTC

1// This file is part of libptytty. Do not make local modifications.
2// http://software.schmorp.de/pkg/libptytty
3
4/*----------------------------------------------------------------------* 1/*----------------------------------------------------------------------*
5 * File: ptytty.C 2 * File: ptytty.C
6 *----------------------------------------------------------------------* 3 *----------------------------------------------------------------------*
7 * 4 *
8 * All portions of code are copyright by their respective author/s. 5 * All portions of code are copyright by their respective author/s.
9 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com> 6 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com>
10 * Copyright (c) 2004-2006 Marc Lehmann <pcg@goof.com> 7 * Copyright (c) 2004-2006 Marc Lehmann <schmorp@schmorp.de>
11 * Copyright (c) 2006 Emanuele Giaquinta <e.giaquinta@glauco.it> 8 * Copyright (c) 2006 Emanuele Giaquinta <e.giaquinta@glauco.it>
12 * 9 *
13 * This program is free software; you can redistribute it and/or modify 10 * 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 11 * 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 12 * the Free Software Foundation; either version 2 of the License, or
… …
23 * You should have received a copy of the GNU General Public License 20 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software 21 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 *---------------------------------------------------------------------*/ 23 *---------------------------------------------------------------------*/
27 24
28#include "../config.h" 25#include "config.h"
29 26
30#include "ptytty.h" 27#include "ptytty.h"
31 28
32#include <cstdlib> 29#include <stdlib.h>
30#include <cstdio>
33#include <cstring> 31#include <string.h>
34 32
35#include <sys/types.h> 33#include <sys/types.h>
36#include <sys/socket.h> 34#include <sys/stat.h>
37#include <unistd.h> 35#include <unistd.h>
38#include <fcntl.h> 36#include <fcntl.h>
39 37
40#ifdef HAVE_SYS_IOCTL_H 38#ifdef HAVE_SYS_IOCTL_H
41# include <sys/ioctl.h> 39# include <sys/ioctl.h>
42#endif 40#endif
43#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H) 41#if defined(HAVE_SYS_STROPTS_H)
44# include <sys/stropts.h> /* for I_PUSH */ 42# include <sys/stropts.h> /* for I_PUSH */
45#endif 43#endif
46#ifdef HAVE_ISASTREAM 44#if defined(HAVE_ISASTREAM) && defined(HAVE_STROPTS_H)
47# include <stropts.h> 45# include <stropts.h>
48#endif 46#endif
49#if defined(HAVE_PTY_H) 47#if defined(HAVE_PTY_H)
50# include <pty.h> 48# include <pty.h>
51#elif defined(HAVE_LIBUTIL_H) 49#elif defined(HAVE_LIBUTIL_H)
… …
55#endif 53#endif
56#ifdef TTY_GID_SUPPORT 54#ifdef TTY_GID_SUPPORT
57#include <grp.h> 55#include <grp.h>
58#endif 56#endif
59 57
60#include <cstdio> 58#ifndef O_NOCTTY
59# define O_NOCTTY 0
60#endif
61 61
62///////////////////////////////////////////////////////////////////////////// 62/////////////////////////////////////////////////////////////////////////////
63 63
64/* ------------------------------------------------------------------------- * 64/* ------------------------------------------------------------------------- *
65 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 65 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
66 * ------------------------------------------------------------------------- */ 66 * ------------------------------------------------------------------------- */
67/* 67/*
68 * Returns pty file descriptor, or -1 on failure 68 * Returns pty file descriptor, or -1 on failure
69 * If successful, ttydev is set to the name of the slave device. 69 * If successful, ttydev is set to the name of the slave device.
70 * fd_tty _may_ also be set to an open fd to the slave device 70 * fd_tty _may_ also be set to an open fd to the slave device
71 */ 71 */
72#if defined(UNIX98_PTY) 72#if defined(UNIX98_PTY)
73
73static int 74 static int
74get_pty (int *fd_tty, char **ttydev) 75 get_pty (int *fd_tty, char **ttydev)
75{ 76 {
76 int pfd; 77 int pfd;
77 78
78# if defined(HAVE_GETPT) 79# if defined(HAVE_GETPT)
79 pfd = getpt(); 80 pfd = getpt ();
80# elif defined(HAVE_POSIX_OPENPT) 81# elif defined(HAVE_POSIX_OPENPT)
81 pfd = posix_openpt (O_RDWR); 82 pfd = posix_openpt (O_RDWR | O_NOCTTY);
82# else 83# else
84# ifdef _AIX
83 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); 85 pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0);
86# else
87 pfd = open ("/dev/ptmx", O_RDWR | O_NOCTTY, 0);
88# endif
84# endif 89# endif
90
85 if (pfd >= 0) 91 if (pfd >= 0)
86 { 92 {
87 if (grantpt (pfd) == 0 /* change slave permissions */ 93 if (grantpt (pfd) == 0 /* change slave permissions */
88 && unlockpt (pfd) == 0) 94 && unlockpt (pfd) == 0)
95 {
89 { /* slave now unlocked */ 96 /* slave now unlocked */
90 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 97 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
91 return pfd; 98 return pfd;
92 } 99 }
93 100
94 close (pfd); 101 close (pfd);
95 } 102 }
96 103
97 return -1; 104 return -1;
98} 105 }
106
99#elif defined(HAVE_OPENPTY) 107#elif defined(HAVE_OPENPTY)
108
100static int 109 static int
101get_pty (int *fd_tty, char **ttydev) 110 get_pty (int *fd_tty, char **ttydev)
102{ 111 {
103 int pfd; 112 int pfd;
104 int res; 113 int res;
105 char tty_name[32]; 114
106
107 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 115 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
116
108 if (res != -1) 117 if (res != -1)
109 { 118 {
110 *ttydev = strdup (tty_name); 119 *ttydev = strdup (ttyname (*fd_tty));
111 return pfd; 120 return pfd;
112 } 121 }
113 122
114 return -1; 123 return -1;
115} 124 }
125
116#elif defined(HAVE__GETPTY) 126#elif defined(HAVE__GETPTY)
127
117static int 128 static int
118get_pty (int *fd_tty, char **ttydev) 129 get_pty (int *fd_tty, char **ttydev)
119{ 130 {
120 int pfd; 131 int pfd;
132 char *slave;
121 133
122 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 134 slave = _getpty (&pfd, O_RDWR | O_NOCTTY, 0622, 0);
123 if (*ttydev != NULL)
124 return pfd;
125 135
126 return -1; 136 if (slave != NULL)
127}
128#elif defined(HAVE_DEV_PTC)
129static int
130get_pty (int *fd_tty, char **ttydev)
131{
132 int pfd;
133
134 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
135 { 137 {
136 *ttydev = strdup (ttyname (pfd)); 138 *ttydev = strdup (slave);
137 return pfd; 139 return pfd;
138 } 140 }
139 141
140 return -1; 142 return -1;
141}
142#elif defined(HAVE_DEV_CLONE)
143static int
144get_pty (int *fd_tty, char **ttydev)
145{
146 int pfd;
147
148 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0)
149 {
150 *ttydev = strdup (ptsname (pfd));
151 return pfd;
152 } 143 }
153 144
154 return -1;
155}
156#else 145#else
146
157/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 147 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
158static int 148 static int
159get_pty (int *fd_tty, char **ttydev) 149 get_pty (int *fd_tty, char **ttydev)
160{ 150 {
161 int pfd; 151 int pfd;
162 int i; 152 int i;
163 char pty_name[32]; 153 char pty_name[32];
164 char tty_name[32]; 154 char tty_name[32];
165 const char *majors = "pqrstuvwxyzabcde"; 155 const char *majors = "pqrstuvwxyzabcde";
166 const char *minors = "0123456789abcdef"; 156 const char *minors = "0123456789abcdef";
157
167 for (i = 0; i < 256; i++) 158 for (i = 0; i < 256; i++)
168 { 159 {
169 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]); 160 snprintf (pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]);
170 snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]); 161 snprintf (tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]);
162
171 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 163 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
172 { 164 {
173 snprintf(pty_name, 32, "/dev/ptyp%d", i); 165 snprintf (pty_name, 32, "/dev/ptyp%d", i);
174 snprintf(tty_name, 32, "/dev/ttyp%d", i); 166 snprintf (tty_name, 32, "/dev/ttyp%d", i);
175 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 167 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
176 continue; 168 continue;
177 } 169 }
170
178 if (access (tty_name, R_OK | W_OK) == 0) 171 if (access (tty_name, R_OK | W_OK) == 0)
179 { 172 {
180 *ttydev = strdup (tty_name); 173 *ttydev = strdup (tty_name);
181 return pfd; 174 return pfd;
182 } 175 }
183 176
184 close (pfd); 177 close (pfd);
185 } 178 }
186} 179
180 return -1;
181 }
182
187#endif 183#endif
188 184
189/*----------------------------------------------------------------------*/ 185/*----------------------------------------------------------------------*/
190/* 186/*
191 * Returns tty file descriptor, or -1 on failure 187 * Returns tty file descriptor, or -1 on failure
192 */ 188 */
193static int 189static int
194get_tty (char *ttydev) 190get_tty (char *ttydev)
195{ 191{
196 return open (ttydev, O_RDWR | O_NOCTTY, 0); 192 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
201 * Make our tty a controlling tty so that /dev/tty points to us 197 * Make our tty a controlling tty so that /dev/tty points to us
202 */ 198 */
203static int 199static int
204control_tty (int fd_tty) 200control_tty (int fd_tty)
205{ 201{
202 int fd;
203
206 setsid (); 204 setsid ();
207 205
208#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 206#ifdef TIOCSCTTY
207 ioctl (fd_tty, TIOCSCTTY, NULL);
208#else
209 fd = open (ttyname (fd_tty), O_RDWR);
210 if (fd >= 0)
211 close (fd);
212#endif
213
214 fd = open ("/dev/tty", O_WRONLY);
215 if (fd < 0)
216 return -1; /* fatal */
217
218 close (fd);
219
220 return 0;
221}
222
223void
224ptytty::close_tty ()
225{
226 if (tty < 0)
227 return;
228
229 close (tty);
230 tty = -1;
231}
232
233bool
234ptytty::make_controlling_tty ()
235{
236 return control_tty (tty) >= 0;
237}
238
239void
240ptytty::set_utf8_mode (bool on)
241{
242#ifdef IUTF8
243 if (pty < 0)
244 return;
245
246 struct termios tio;
247
248 if (tcgetattr (pty, &tio) != -1)
249 {
250 tcflag_t new_cflag = tio.c_iflag;
251
252 if (on)
253 new_cflag |= IUTF8;
254 else
255 new_cflag &= ~IUTF8;
256
257 if (new_cflag != tio.c_iflag)
258 {
259 tio.c_iflag = new_cflag;
260 tcsetattr (pty, TCSANOW, &tio);
261 }
262 }
263#endif
264}
265
266static struct ttyconf {
267 gid_t gid;
268 mode_t mode;
269
270 ttyconf ()
271 {
272#ifdef TTY_GID_SUPPORT
273 struct group *gr = getgrnam ("tty");
274
275 if (gr)
276 {
277 /* change group ownership of tty to "tty" */
278 mode = S_IRUSR | S_IWUSR | S_IWGRP;
279 gid = gr->gr_gid;
280 }
281 else
282#endif /* TTY_GID_SUPPORT */
283 {
284 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
285 gid = 0;
286 }
287 }
288} ttyconf;
289
290ptytty_unix::ptytty_unix ()
291{
292 name = 0;
293#if UTMP_SUPPORT
294 cmd_pid = 0;
295#endif
296}
297
298ptytty_unix::~ptytty_unix ()
299{
300#if UTMP_SUPPORT
301 logout ();
302#endif
303 put ();
304}
305
306void
307ptytty_unix::put ()
308{
309 if (name)
310 {
311 chmod (name, RESTORE_TTY_MODE);
312 chown (name, 0, ttyconf.gid);
313 }
314
315 close_tty ();
316
317 if (pty >= 0)
318 close (pty);
319
320 free (name);
321
322 pty = tty = -1;
323 name = 0;
324}
325
326bool
327ptytty_unix::get ()
328{
329 /* get master (pty) */
330 if ((pty = get_pty (&tty, &name)) < 0)
331 return false;
332
333 /* get slave (tty) */
334 if (tty < 0)
335 {
336#ifndef NO_SETOWNER_TTYDEV
337 chown (name, getuid (), ttyconf.gid); /* fail silently */
338 chmod (name, ttyconf.mode);
339# ifdef HAVE_REVOKE
340 revoke (name);
341# endif
342#endif
343
344 if ((tty = get_tty (name)) < 0)
345 {
346 put ();
347 return false;
348 }
349 }
350
351#if defined(I_PUSH)
209 /* 352 /*
210 * Push STREAMS modules: 353 * Push STREAMS modules:
211 * ptem: pseudo-terminal hardware emulation module. 354 * ptem: pseudo-terminal hardware emulation module.
212 * ldterm: standard terminal line discipline. 355 * ldterm: standard terminal line discipline.
213 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module. 356 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module.
214 * 357 *
215 * After we push the STREAMS modules, the first open () on the slave side 358 * After we push the STREAMS modules, the first open () on the slave side
216 * (i.e. the next section between the dashes giving us "tty opened OK")
217 * should make the "ptem" (or "ldterm" depending upon either which OS 359 * should make the "ptem" (or "ldterm" depending upon either which OS
218 * version or which set of manual pages you have) module give us a 360 * version or which set of manual pages you have) module give us a
219 * controlling terminal. We must already have close ()d the master side 361 * controlling terminal. We must already have close ()d the master side
220 * fd in this child process before we push STREAMS modules on because the 362 * fd in this child process before we push STREAMS modules on because the
221 * documentation is really unclear about whether it is any close () on 363 * documentation is really unclear about whether it is any close () on
222 * the master side or the last close () - i.e. a proper STREAMS dismantling 364 * the master side or the last close () - i.e. a proper STREAMS dismantling
223 * close () - on the master side which causes a hang up to be sent 365 * close () - on the master side which causes a hang up to be sent
224 * through - Geoff Wing 366 * through - Geoff Wing
225 */ 367 */
226# ifdef HAVE_ISASTREAM 368#if defined(HAVE_ISASTREAM) && defined(HAVE_STROPTS_H)
227 if (isastream (fd_tty) == 1) 369 if (isastream (tty) == 1)
228# endif 370# endif
229 { 371 {
230 ioctl (fd_tty, I_PUSH, "ptem"); 372 ioctl (tty, I_PUSH, "ptem");
231 ioctl (fd_tty, I_PUSH, "ldterm"); 373 ioctl (tty, I_PUSH, "ldterm");
232 ioctl (fd_tty, I_PUSH, "ttcompat"); 374 ioctl (tty, I_PUSH, "ttcompat");
233 }
234#endif
235
236 ioctl (fd_tty, TIOCSCTTY, NULL);
237
238 int fd = open ("/dev/tty", O_WRONLY);
239 if (fd < 0)
240 return -1; /* fatal */
241
242 close (fd);
243
244 return 0;
245}
246
247void
248ptytty::close_tty ()
249{
250 if (tty < 0)
251 return;
252
253 close (tty);
254 tty = -1;
255}
256
257bool
258ptytty::make_controlling_tty ()
259{
260 return control_tty (tty) >= 0;
261}
262
263void
264ptytty::set_utf8_mode (bool on)
265{
266#ifdef IUTF8
267 if (pty < 0)
268 return;
269
270 struct termios tio;
271
272 if (tcgetattr (pty, &tio) != -1)
273 { 375 }
274 tcflag_t new_cflag = tio.c_iflag;
275
276 if (on)
277 new_cflag |= IUTF8;
278 else
279 new_cflag &= ~IUTF8;
280
281 if (new_cflag != tio.c_iflag)
282 {
283 tio.c_iflag = new_cflag;
284 tcsetattr (pty, TCSANOW, &tio);
285 }
286 }
287#endif 376#endif
288}
289 377
290static struct ttyconf {
291 gid_t gid;
292 mode_t mode;
293
294 ttyconf ()
295 {
296#ifdef TTY_GID_SUPPORT
297 struct group *gr = getgrnam ("tty");
298
299 if (gr)
300 { /* change group ownership of tty to "tty" */
301 mode = S_IRUSR | S_IWUSR | S_IWGRP;
302 gid = gr->gr_gid;
303 }
304 else
305#endif /* TTY_GID_SUPPORT */
306 {
307 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
308 gid = 0;
309 }
310 }
311} ttyconf;
312
313ptytty_unix::ptytty_unix ()
314{
315 name = 0;
316#if UTMP_SUPPORT 378#if UTMP_SUPPORT
317 cmd_pid = 0; 379# if defined(HAVE_STRUCT_UTMP) && !defined(HAVE_UTMP_PID)
318#endif 380 int fd_stdin = dup (STDIN_FILENO);
319} 381 dup2 (tty, STDIN_FILENO);
320 382
321ptytty_unix::~ptytty_unix () 383 utmp_pos = ttyslot ();
322{
323#if UTMP_SUPPORT
324 logout ();
325#endif
326 put ();
327}
328 384
329void 385 dup2 (fd_stdin, STDIN_FILENO);
330ptytty_unix::put () 386 close (fd_stdin);
331{
332 chmod (name, RESTORE_TTY_MODE);
333 chown (name, 0, ttyconf.gid);
334
335 close_tty ();
336
337 if (pty >= 0)
338 close (pty);
339
340 free (name);
341
342 pty = tty = -1;
343 name = 0;
344}
345
346bool
347ptytty_unix::get ()
348{
349 /* get master (pty) */
350 if ((pty = get_pty (&tty, &name)) < 0)
351 return false;
352
353 fcntl (pty, F_SETFL, O_NONBLOCK);
354
355 /* get slave (tty) */
356 if (tty < 0)
357 {
358#ifndef NO_SETOWNER_TTYDEV
359 chown (name, getuid (), ttyconf.gid); /* fail silently */
360 chmod (name, ttyconf.mode);
361# ifdef HAVE_REVOKE
362 revoke (name);
363# endif 387# endif
364#endif 388#endif
365 389
366 if ((tty = get_tty (name)) < 0)
367 {
368 put ();
369 return false;
370 }
371 }
372
373 return true; 390 return true;
374} 391}
375 392
376/////////////////////////////////////////////////////////////////////////////
377// helper/proxy support
378
379#if PTYTTY_HELPER
380
381static int sock_fd = -1;
382static int helper_pid, owner_pid;
383
384struct command
385{
386 enum { get, login, destroy } type;
387
388 ptytty *id;
389
390 bool login_shell;
391 int cmd_pid;
392 char hostname[512]; // arbitrary, but should be plenty
393};
394
395struct ptytty_proxy : ptytty
396{
397 ptytty *id;
398
399 ptytty_proxy ()
400 : id(0)
401 {
402 }
403
404 ~ptytty_proxy ();
405
406 bool get ();
407 void login (int cmd_pid, bool login_shell, const char *hostname);
408};
409
410bool
411ptytty_proxy::get ()
412{
413 command cmd;
414
415 cmd.type = command::get;
416
417 write (sock_fd, &cmd, sizeof (cmd));
418
419 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
420 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
421
422 if (!id)
423 return false;
424
425 if ((pty = recv_fd (sock_fd)) < 0
426 || (tty = recv_fd (sock_fd)) < 0)
427 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
428
429 return true;
430}
431
432void
433ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
434{
435 command cmd;
436
437 cmd.type = command::login;
438 cmd.id = id;
439 cmd.cmd_pid = cmd_pid;
440 cmd.login_shell = login_shell;
441 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
442
443 write (sock_fd, &cmd, sizeof (cmd));
444}
445
446ptytty_proxy::~ptytty_proxy ()
447{
448 if (id)
449 {
450 command cmd;
451
452 cmd.type = command::destroy;
453 cmd.id = id;
454
455 write (sock_fd, &cmd, sizeof (cmd));
456 }
457}
458
459static
460void serve ()
461{
462 command cmd;
463 vector<ptytty *> ptys;
464
465 while (read (sock_fd, &cmd, sizeof (command)) == sizeof (command))
466 {
467 if (cmd.type == command::get)
468 {
469 // -> id ptyfd ttyfd
470 cmd.id = new ptytty_unix;
471
472 if (cmd.id->get ())
473 {
474 write (sock_fd, &cmd.id, sizeof (cmd.id));
475 ptys.push_back (cmd.id);
476
477 ptytty::send_fd (sock_fd, cmd.id->pty);
478 ptytty::send_fd (sock_fd, cmd.id->tty);
479 }
480 else
481 {
482 delete cmd.id;
483 cmd.id = 0;
484 write (sock_fd, &cmd.id, sizeof (cmd.id));
485 }
486 }
487 else if (cmd.type == command::login)
488 {
489#if UTMP_SUPPORT
490 if (find (ptys.begin (), ptys.end (), cmd.id) != ptys.end ())
491 {
492 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
493 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
494 }
495#endif
496 }
497 else if (cmd.type == command::destroy)
498 {
499 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
500
501 if (pty != ptys.end ())
502 {
503 delete *pty;
504 ptys.erase (pty);
505 }
506 }
507 else
508 break;
509 }
510
511 // destroy all ptys
512 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
513 delete *i;
514}
515
516void
517ptytty::use_helper ()
518{
519 int pid = getpid ();
520
521 if (sock_fd >= 0 && pid == owner_pid)
522 return;
523
524 owner_pid = pid;
525
526 int sv[2];
527
528 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
529 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
530
531 helper_pid = fork ();
532
533 if (helper_pid < 0)
534 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
535
536 if (helper_pid)
537 {
538 // client, process
539 sock_fd = sv[0];
540 close (sv[1]);
541 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
542 }
543 else
544 {
545 // server, pty-helper
546 sock_fd = sv[1];
547
548 chdir ("/");
549
550 for (int fd = 0; fd < 1023; fd++)
551 if (fd != sock_fd)
552 close (fd);
553
554 serve ();
555 _exit (EXIT_SUCCESS);
556 }
557}
558
559#endif
560
561ptytty *
562ptytty::create ()
563{
564#if PTYTTY_HELPER
565 if (helper_pid && getpid () == owner_pid)
566 // use helper process
567 return new ptytty_proxy;
568 else
569#endif
570 return new ptytty_unix;
571}
572
573void
574ptytty::init ()
575{
576 uid_t uid = getuid ();
577 gid_t gid = getgid ();
578
579 // before doing anything else, check for setuid/setgid operation,
580 // start the helper process and drop privileges
581 if (uid != geteuid ()
582 || gid != getegid ())
583 {
584#if PTYTTY_HELPER
585 use_helper ();
586#else
587 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
588#endif
589
590 drop_privileges ();
591 }
592}
593
594void
595ptytty::drop_privileges ()
596{
597 uid_t uid = getuid ();
598 gid_t gid = getgid ();
599
600 // drop privileges
601#if HAVE_SETRESUID
602 setresgid (gid, gid, gid);
603 setresuid (uid, uid, uid);
604#elif HAVE_SETREUID
605 setregid (gid, gid);
606 setreuid (uid, uid);
607#elif HAVE_SETUID
608 setgid (gid);
609 setuid (uid);
610#endif
611
612 if (uid != geteuid ()
613 || gid != getegid ())
614 ptytty_fatal ("unable to drop privileges, aborting.\n");
615}
616
617/////////////////////////////////////////////////////////////////////////////
618// C API
619
620#ifndef NO_C_API
621
622#define DEFINE_METHOD(retval, name, args1, args2) \
623extern "C" retval ptytty_ ## name args1 \
624{ return ((struct ptytty *)ptytty)->name args2; }
625
626DEFINE_METHOD(int,pty,(void *ptytty),)
627DEFINE_METHOD(int,tty,(void *ptytty),)
628DEFINE_METHOD(int,get,(void *ptytty),())
629DEFINE_METHOD(void,login,(void *ptytty, int cmd_pid, bool login_shell, const char *hostname),(cmd_pid,login_shell,hostname))
630
631DEFINE_METHOD(void,close_tty,(void *ptytty),())
632DEFINE_METHOD(int,make_controlling_tty,(void *ptytty),())
633DEFINE_METHOD(void,set_utf8_mode,(void *ptytty, int on),(on))
634
635#define DEFINE_STATIC(retval, name, args) \
636extern "C" retval ptytty_ ## name args \
637{ return ptytty::name args; }
638
639DEFINE_STATIC(void,init,())
640DEFINE_STATIC(void *,create,())
641
642void ptytty_delete (void *ptytty)
643{
644 delete (struct ptytty *)ptytty;
645}
646
647DEFINE_STATIC(void,drop_privileges,())
648DEFINE_STATIC(void,use_helper,())
649
650#endif

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