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Comparing libptytty/src/ptytty.C (file contents):
Revision 1.15 by root, Mon Jan 23 11:22:08 2006 UTC vs.
Revision 1.45 by sf-exg, Tue Dec 20 16:09:32 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 35
35#include <sys/types.h> 36#include <sys/types.h>
36#include <sys/socket.h> 37#include <sys/stat.h>
37#include <unistd.h> 38#include <unistd.h>
38#include <fcntl.h> 39#include <fcntl.h>
39 40
40#ifdef HAVE_SYS_IOCTL_H 41#ifdef HAVE_SYS_IOCTL_H
41# include <sys/ioctl.h> 42# include <sys/ioctl.h>
42#endif 43#endif
43#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H) 44#if defined(HAVE_SYS_STROPTS_H)
44# include <sys/stropts.h> /* for I_PUSH */ 45# include <sys/stropts.h> /* for I_PUSH */
45#endif 46#endif
46#ifdef HAVE_ISASTREAM 47#if defined(HAVE_ISASTREAM) && defined(HAVE_STROPTS_H)
47# include <stropts.h> 48# include <stropts.h>
48#endif 49#endif
49#if defined(HAVE_PTY_H) 50#if defined(HAVE_PTY_H)
50# include <pty.h> 51# include <pty.h>
51#elif defined(HAVE_LIBUTIL_H) 52#elif defined(HAVE_LIBUTIL_H)
… …
63 64
64/* ------------------------------------------------------------------------- * 65/* ------------------------------------------------------------------------- *
65 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 66 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
66 * ------------------------------------------------------------------------- */ 67 * ------------------------------------------------------------------------- */
67/* 68/*
68 * Returns pty file descriptor, or -1 on failure 69 * Returns pty file descriptor, or -1 on failure
69 * 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.
70 * 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
71 */ 72 */
72#if defined(UNIX98_PTY) 73#if defined(UNIX98_PTY)
74
73static int 75 static int
74get_pty (int *fd_tty, char **ttydev) 76 get_pty (int *fd_tty, char **ttydev)
75{ 77 {
76 int pfd; 78 int pfd;
77 79
78# if defined(HAVE_GETPT) 80# if defined(HAVE_GETPT)
79 pfd = getpt(); 81 pfd = getpt ();
80# elif defined(HAVE_POSIX_OPENPT) 82# elif defined(HAVE_POSIX_OPENPT)
81 pfd = posix_openpt (O_RDWR); 83 pfd = posix_openpt (O_RDWR | O_NOCTTY);
82# else 84# else
85# ifdef _AIX
83 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
84# endif 90# endif
91
85 if (pfd >= 0) 92 if (pfd >= 0)
86 { 93 {
87 if (grantpt (pfd) == 0 /* change slave permissions */ 94 if (grantpt (pfd) == 0 /* change slave permissions */
88 && unlockpt (pfd) == 0) 95 && unlockpt (pfd) == 0)
96 {
89 { /* slave now unlocked */ 97 /* slave now unlocked */
90 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 98 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
91 return pfd; 99 return pfd;
92 } 100 }
93 101
94 close (pfd); 102 close (pfd);
95 } 103 }
96 104
97 return -1; 105 return -1;
98} 106 }
107
99#elif defined(HAVE_OPENPTY) 108#elif defined(HAVE_OPENPTY)
109
100static int 110 static int
101get_pty (int *fd_tty, char **ttydev) 111 get_pty (int *fd_tty, char **ttydev)
102{ 112 {
103 int pfd; 113 int pfd;
104 int res; 114 int res;
105 char tty_name[32]; 115
106
107 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 116 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
117
108 if (res != -1) 118 if (res != -1)
109 { 119 {
110 *ttydev = strdup (tty_name); 120 *ttydev = strdup (ttyname (*fd_tty));
111 return pfd; 121 return pfd;
112 } 122 }
113 123
114 return -1; 124 return -1;
115} 125 }
126
116#elif defined(HAVE__GETPTY) 127#elif defined(HAVE__GETPTY)
128
117static int 129 static int
118get_pty (int *fd_tty, char **ttydev) 130 get_pty (int *fd_tty, char **ttydev)
119{ 131 {
120 int pfd; 132 int pfd;
133 char *slave;
121 134
122 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 135 slave = _getpty (&pfd, O_RDWR | O_NOCTTY, 0622, 0);
123 if (*ttydev != NULL)
124 return pfd;
125 136
126 return -1; 137 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 { 138 {
136 *ttydev = strdup (ttyname (pfd)); 139 *ttydev = strdup (slave);
137 return pfd; 140 return pfd;
138 } 141 }
139 142
140 return -1; 143 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 } 144 }
153 145
154 return -1;
155}
156#else 146#else
147
157/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 148 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
158static int 149 static int
159get_pty (int *fd_tty, char **ttydev) 150 get_pty (int *fd_tty, char **ttydev)
160{ 151 {
161 int pfd; 152 int pfd;
162 int i; 153 int i;
163 char pty_name[32]; 154 char pty_name[32];
164 char tty_name[32]; 155 char tty_name[32];
165 const char *majors = "pqrstuvwxyzabcde"; 156 const char *majors = "pqrstuvwxyzabcde";
166 const char *minors = "0123456789abcdef"; 157 const char *minors = "0123456789abcdef";
158
167 for (i = 0; i < 256; i++) 159 for (i = 0; i < 256; i++)
168 { 160 {
169 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]);
170 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
171 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 164 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
172 { 165 {
173 snprintf(pty_name, 32, "/dev/ptyp%d", i); 166 snprintf (pty_name, 32, "/dev/ptyp%d", i);
174 snprintf(tty_name, 32, "/dev/ttyp%d", i); 167 snprintf (tty_name, 32, "/dev/ttyp%d", i);
175 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 168 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
176 continue; 169 continue;
177 } 170 }
171
178 if (access (tty_name, R_OK | W_OK) == 0) 172 if (access (tty_name, R_OK | W_OK) == 0)
179 { 173 {
180 *ttydev = strdup (tty_name); 174 *ttydev = strdup (tty_name);
181 return pfd; 175 return pfd;
182 } 176 }
183 177
184 close (pfd); 178 close (pfd);
185 } 179 }
186} 180
181 return -1;
182 }
183
187#endif 184#endif
188 185
189/*----------------------------------------------------------------------*/ 186/*----------------------------------------------------------------------*/
190/* 187/*
191 * Returns tty file descriptor, or -1 on failure 188 * Returns tty file descriptor, or -1 on failure
192 */ 189 */
193static int 190static int
194get_tty (char *ttydev) 191get_tty (char *ttydev)
195{ 192{
196 return open (ttydev, O_RDWR | O_NOCTTY, 0); 193 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
201 * 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
202 */ 199 */
203static int 200static int
204control_tty (int fd_tty) 201control_tty (int fd_tty)
205{ 202{
203 int fd;
204
206 setsid (); 205 setsid ();
207 206
208#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 /* get slave (tty) */
335 if (tty < 0)
336 {
337#ifndef NO_SETOWNER_TTYDEV
338 chown (name, getuid (), ttyconf.gid); /* fail silently */
339 chmod (name, ttyconf.mode);
340# ifdef HAVE_REVOKE
341 revoke (name);
342# endif
343#endif
344
345 if ((tty = get_tty (name)) < 0)
346 {
347 put ();
348 return false;
349 }
350 }
351
352#if defined(I_PUSH)
209 /* 353 /*
210 * Push STREAMS modules: 354 * Push STREAMS modules:
211 * ptem: pseudo-terminal hardware emulation module. 355 * ptem: pseudo-terminal hardware emulation module.
212 * ldterm: standard terminal line discipline. 356 * ldterm: standard terminal line discipline.
213 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module. 357 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module.
214 * 358 *
215 * After we push the STREAMS modules, the first open () on the slave side 359 * 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 360 * 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 361 * 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 362 * 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 363 * 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 364 * 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 365 * 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 366 * close () - on the master side which causes a hang up to be sent
224 * through - Geoff Wing 367 * through - Geoff Wing
225 */ 368 */
226# ifdef HAVE_ISASTREAM 369#if defined(HAVE_ISASTREAM) && defined(HAVE_STROPTS_H)
227 if (isastream (fd_tty) == 1) 370 if (isastream (tty) == 1)
228# endif 371# endif
229 { 372 {
230 ioctl (fd_tty, I_PUSH, "ptem"); 373 ioctl (tty, I_PUSH, "ptem");
231 ioctl (fd_tty, I_PUSH, "ldterm"); 374 ioctl (tty, I_PUSH, "ldterm");
232 ioctl (fd_tty, I_PUSH, "ttcompat"); 375 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 { 376 }
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 377#endif
288}
289 378
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 379#if UTMP_SUPPORT
317 cmd_pid = 0; 380# if defined(HAVE_STRUCT_UTMP) && !defined(HAVE_UTMP_PID)
318#endif 381 int fd_stdin = dup (STDIN_FILENO);
319} 382 dup2 (tty, STDIN_FILENO);
320 383
321ptytty_unix::~ptytty_unix () 384 utmp_pos = ttyslot ();
322{
323#if UTMP_SUPPORT
324 logout ();
325#endif
326 put ();
327}
328 385
329void 386 dup2 (fd_stdin, STDIN_FILENO);
330ptytty_unix::put () 387 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 388# endif
364#endif 389#endif
365 390
366 if ((tty = get_tty (name)) < 0)
367 {
368 put ();
369 return false;
370 }
371 }
372
373 return true; 391 return true;
374} 392}
375 393
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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