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Revision 1.10 by root, Sun Jan 22 04:05:19 2006 UTC vs.
Revision 1.52 by sf-exg, Thu Jan 19 20:07:14 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>
8 * Copyright (c) 2006 Emanuele Giaquinta <e.giaquinta@glauco.it>
11 * 9 *
12 * 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
13 * 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
14 * the Free Software Foundation; either version 2 of the License, or 12 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version. 13 * (at your option) any later version.
… …
22 * 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
23 * along with this program; if not, write to the Free Software 21 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 *---------------------------------------------------------------------*/ 23 *---------------------------------------------------------------------*/
26 24
27#include "../config.h" 25#include "config.h"
28 26
29#include "ptytty.h" 27#include "ptytty.h"
30 28
31#include <cstdlib> 29#include <stdlib.h>
30#include <stdio.h>
32#include <cstring> 31#include <string.h>
33 32
34#include <sys/types.h> 33#include <sys/types.h>
35#include <sys/socket.h> 34#include <sys/stat.h>
36#include <unistd.h> 35#include <unistd.h>
37#include <fcntl.h> 36#include <fcntl.h>
38 37
39#ifdef HAVE_SYS_IOCTL_H 38#ifdef HAVE_SYS_IOCTL_H
40# include <sys/ioctl.h> 39# include <sys/ioctl.h>
41#endif 40#endif
42#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H) 41#ifdef HAVE_STROPTS_H
43# include <sys/stropts.h> /* for I_PUSH */
44#endif
45#ifdef HAVE_ISASTREAM
46# include <stropts.h> 42# include <stropts.h>
47#endif 43#endif
48#if defined(HAVE_PTY_H) 44#if defined(HAVE_PTY_H)
49# include <pty.h> 45# include <pty.h>
50#elif defined(HAVE_LIBUTIL_H) 46#elif defined(HAVE_LIBUTIL_H)
… …
54#endif 50#endif
55#ifdef TTY_GID_SUPPORT 51#ifdef TTY_GID_SUPPORT
56#include <grp.h> 52#include <grp.h>
57#endif 53#endif
58 54
59#include <cstdio> 55#ifndef O_NOCTTY
56# define O_NOCTTY 0
57#endif
60 58
61///////////////////////////////////////////////////////////////////////////// 59/////////////////////////////////////////////////////////////////////////////
62 60
63/* ------------------------------------------------------------------------- * 61/* ------------------------------------------------------------------------- *
64 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 62 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
65 * ------------------------------------------------------------------------- */ 63 * ------------------------------------------------------------------------- */
66/* 64/*
67 * Returns pty file descriptor, or -1 on failure 65 * Returns pty file descriptor, or -1 on failure
68 * If successful, ttydev is set to the name of the slave device. 66 * If successful, ttydev is set to the name of the slave device.
69 * fd_tty _may_ also be set to an open fd to the slave device 67 * fd_tty _may_ also be set to an open fd to the slave device
70 */ 68 */
71#if defined(UNIX98_PTY) 69#if defined(UNIX98_PTY)
70
72static int 71 static int
73get_pty (int *fd_tty, char **ttydev) 72 get_pty (int *fd_tty, char **ttydev)
74{ 73 {
75 int pfd; 74 int pfd;
76 75
77# if defined(HAVE_GETPT) 76# if defined(HAVE_GETPT)
78 pfd = getpt(); 77 pfd = getpt ();
79# elif defined(HAVE_POSIX_OPENPT) 78# elif defined(HAVE_POSIX_OPENPT)
80 pfd = posix_openpt (O_RDWR); 79 pfd = posix_openpt (O_RDWR | O_NOCTTY);
81# else 80# else
81# ifdef _AIX
82 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); 82 pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0);
83# else
84 pfd = open ("/dev/ptmx", O_RDWR | O_NOCTTY, 0);
85# endif
83# endif 86# endif
87
84 if (pfd >= 0) 88 if (pfd >= 0)
85 { 89 {
86 if (grantpt (pfd) == 0 /* change slave permissions */ 90 if (grantpt (pfd) == 0 /* change slave permissions */
87 && unlockpt (pfd) == 0) 91 && unlockpt (pfd) == 0)
92 {
88 { /* slave now unlocked */ 93 /* slave now unlocked */
89 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 94 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
90 return pfd; 95 return pfd;
91 } 96 }
92 97
93 close (pfd); 98 close (pfd);
94 } 99 }
95 100
96 return -1; 101 return -1;
97} 102 }
103
98#elif defined(HAVE_OPENPTY) 104#elif defined(HAVE_OPENPTY)
105
99static int 106 static int
100get_pty (int *fd_tty, char **ttydev) 107 get_pty (int *fd_tty, char **ttydev)
101{ 108 {
102 int pfd; 109 int pfd;
103 int res; 110 int res;
104 char tty_name[32]; 111
105
106 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 112 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
113
107 if (res != -1) 114 if (res != -1)
108 { 115 {
109 *ttydev = strdup (tty_name); 116 *ttydev = strdup (ttyname (*fd_tty));
110 return pfd; 117 return pfd;
111 } 118 }
112 119
113 return -1; 120 return -1;
114} 121 }
122
115#elif defined(HAVE__GETPTY) 123#elif defined(HAVE__GETPTY)
124
116static int 125 static int
117get_pty (int *fd_tty, char **ttydev) 126 get_pty (int *fd_tty, char **ttydev)
118{ 127 {
119 int pfd; 128 int pfd;
129 char *slave;
120 130
121 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 131 slave = _getpty (&pfd, O_RDWR | O_NOCTTY, 0622, 0);
122 if (*ttydev != NULL)
123 return pfd;
124 132
125 return -1; 133 if (slave != NULL)
126}
127#elif defined(HAVE_DEV_PTC)
128static int
129get_pty (int *fd_tty, char **ttydev)
130{
131 int pfd;
132
133 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
134 { 134 {
135 *ttydev = strdup (ttyname (pfd)); 135 *ttydev = strdup (slave);
136 return pfd; 136 return pfd;
137 } 137 }
138 138
139 return -1; 139 return -1;
140}
141#elif defined(HAVE_DEV_CLONE)
142static int
143get_pty (int *fd_tty, char **ttydev)
144{
145 int pfd;
146
147 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0)
148 {
149 *ttydev = strdup (ptsname (pfd));
150 return pfd;
151 } 140 }
152 141
153 return -1;
154}
155#else 142#else
143
156/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 144 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
157static int 145 static int
158get_pty (int *fd_tty, char **ttydev) 146 get_pty (int *fd_tty, char **ttydev)
159{ 147 {
160 int pfd; 148 int pfd;
161 int i; 149 int i;
162 char pty_name[32]; 150 char pty_name[32];
163 char tty_name[32]; 151 char tty_name[32];
164 const char *majors = "pqrstuvwxyzabcde"; 152 const char *majors = "pqrstuvwxyzabcde";
165 const char *minors = "0123456789abcdef"; 153 const char *minors = "0123456789abcdef";
154
166 for (i = 0; i < 256; i++) 155 for (i = 0; i < 256; i++)
167 { 156 {
168 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]); 157 snprintf (pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]);
169 snprintf(tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]); 158 snprintf (tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]);
159
170 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 160 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
171 { 161 {
172 snprintf(pty_name, 32, "/dev/ptyp%d", i); 162 snprintf (pty_name, 32, "/dev/ptyp%d", i);
173 snprintf(tty_name, 32, "/dev/ttyp%d", i); 163 snprintf (tty_name, 32, "/dev/ttyp%d", i);
174 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 164 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
175 continue; 165 continue;
176 } 166 }
167
177 if (access (tty_name, R_OK | W_OK) == 0) 168 if (access (tty_name, R_OK | W_OK) == 0)
178 { 169 {
179 *ttydev = strdup (tty_name); 170 *ttydev = strdup (tty_name);
180 return pfd; 171 return pfd;
181 } 172 }
182 173
183 close (pfd); 174 close (pfd);
184 } 175 }
185} 176
177 return -1;
178 }
179
186#endif 180#endif
187 181
188/*----------------------------------------------------------------------*/ 182/*----------------------------------------------------------------------*/
189/* 183/*
190 * Returns tty file descriptor, or -1 on failure 184 * Returns tty file descriptor, or -1 on failure
191 */ 185 */
192static int 186static int
193get_tty (char *ttydev) 187get_tty (char *ttydev)
194{ 188{
195 return open (ttydev, O_RDWR | O_NOCTTY, 0); 189 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
200 * Make our tty a controlling tty so that /dev/tty points to us 194 * Make our tty a controlling tty so that /dev/tty points to us
201 */ 195 */
202static int 196static int
203control_tty (int fd_tty) 197control_tty (int fd_tty)
204{ 198{
199 int fd;
200
205 setsid (); 201 setsid ();
206 202
207#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 203#ifdef TIOCSCTTY
204 ioctl (fd_tty, TIOCSCTTY, NULL);
205#else
206 fd = open (ttyname (fd_tty), O_RDWR);
207 if (fd >= 0)
208 close (fd);
209#endif
210
211 fd = open ("/dev/tty", O_WRONLY);
212 if (fd < 0)
213 return -1; /* fatal */
214
215 close (fd);
216
217 return 0;
218}
219
220void
221ptytty::close_tty ()
222{
223 if (tty < 0)
224 return;
225
226 close (tty);
227 tty = -1;
228}
229
230bool
231ptytty::make_controlling_tty ()
232{
233 return control_tty (tty) >= 0;
234}
235
236void
237ptytty::set_utf8_mode (bool on)
238{
239#ifdef IUTF8
240 if (pty < 0)
241 return;
242
243 struct termios tio;
244
245 if (tcgetattr (pty, &tio) != -1)
246 {
247 tcflag_t new_cflag = tio.c_iflag;
248
249 if (on)
250 new_cflag |= IUTF8;
251 else
252 new_cflag &= ~IUTF8;
253
254 if (new_cflag != tio.c_iflag)
255 {
256 tio.c_iflag = new_cflag;
257 tcsetattr (pty, TCSANOW, &tio);
258 }
259 }
260#endif
261}
262
263static struct ttyconf {
264 gid_t gid;
265 mode_t mode;
266
267 ttyconf ()
268 {
269#ifdef TTY_GID_SUPPORT
270 struct group *gr = getgrnam ("tty");
271
272 if (gr)
273 {
274 /* change group ownership of tty to "tty" */
275 mode = S_IRUSR | S_IWUSR | S_IWGRP;
276 gid = gr->gr_gid;
277 }
278 else
279#endif /* TTY_GID_SUPPORT */
280 {
281 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
282 gid = 0;
283 }
284 }
285} ttyconf;
286
287ptytty_unix::ptytty_unix ()
288{
289 name = 0;
290#if UTMP_SUPPORT
291 cmd_pid = 0;
292#endif
293}
294
295ptytty_unix::~ptytty_unix ()
296{
297#if UTMP_SUPPORT
298 logout ();
299#endif
300 put ();
301}
302
303void
304ptytty_unix::put ()
305{
306 if (name)
307 {
308 chmod (name, RESTORE_TTY_MODE);
309 chown (name, 0, ttyconf.gid);
310 }
311
312 close_tty ();
313
314 if (pty >= 0)
315 close (pty);
316
317 free (name);
318
319 pty = tty = -1;
320 name = 0;
321}
322
323bool
324ptytty_unix::get ()
325{
326 /* get master (pty) */
327 if ((pty = get_pty (&tty, &name)) < 0)
328 return false;
329
330 /* get slave (tty) */
331 if (tty < 0)
332 {
333#ifndef NO_SETOWNER_TTYDEV
334 chown (name, getuid (), ttyconf.gid); /* fail silently */
335 chmod (name, ttyconf.mode);
336# ifdef HAVE_REVOKE
337 revoke (name);
338# endif
339#endif
340
341 if ((tty = get_tty (name)) < 0)
342 {
343 put ();
344 return false;
345 }
346 }
347
348#if defined(I_PUSH)
208 /* 349 /*
209 * Push STREAMS modules: 350 * Push STREAMS modules:
210 * ptem: pseudo-terminal hardware emulation module. 351 * ptem: pseudo-terminal hardware emulation module.
211 * ldterm: standard terminal line discipline. 352 * ldterm: standard terminal line discipline.
212 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module. 353 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module.
213 * 354 *
214 * After we push the STREAMS modules, the first open () on the slave side 355 * After we push the STREAMS modules, the first open () on the slave side
215 * (i.e. the next section between the dashes giving us "tty opened OK")
216 * should make the "ptem" (or "ldterm" depending upon either which OS 356 * should make the "ptem" (or "ldterm" depending upon either which OS
217 * version or which set of manual pages you have) module give us a 357 * version or which set of manual pages you have) module give us a
218 * controlling terminal. We must already have close ()d the master side 358 * controlling terminal. We must already have close ()d the master side
219 * fd in this child process before we push STREAMS modules on because the 359 * fd in this child process before we push STREAMS modules on because the
220 * documentation is really unclear about whether it is any close () on 360 * documentation is really unclear about whether it is any close () on
221 * the master side or the last close () - i.e. a proper STREAMS dismantling 361 * the master side or the last close () - i.e. a proper STREAMS dismantling
222 * close () - on the master side which causes a hang up to be sent 362 * close () - on the master side which causes a hang up to be sent
223 * through - Geoff Wing 363 * through - Geoff Wing
224 */ 364 */
225# ifdef HAVE_ISASTREAM 365#if defined(HAVE_ISASTREAM) && defined(HAVE_STROPTS_H)
226 if (isastream (fd_tty) == 1) 366 if (isastream (tty) == 1)
227# endif 367# endif
228 { 368 {
229 ioctl (fd_tty, I_PUSH, "ptem"); 369 ioctl (tty, I_PUSH, "ptem");
230 ioctl (fd_tty, I_PUSH, "ldterm"); 370 ioctl (tty, I_PUSH, "ldterm");
231 ioctl (fd_tty, I_PUSH, "ttcompat"); 371 ioctl (tty, I_PUSH, "ttcompat");
232 }
233#endif
234
235 ioctl (fd_tty, TIOCSCTTY, NULL);
236
237 int fd = open ("/dev/tty", O_WRONLY);
238 if (fd < 0)
239 return -1; /* fatal */
240
241 close (fd);
242
243 return 0;
244}
245
246void
247ptytty::close_tty ()
248{
249 if (tty < 0)
250 return;
251
252 close (tty);
253 tty = -1;
254}
255
256bool
257ptytty::make_controlling_tty ()
258{
259 return control_tty (tty) >= 0;
260}
261
262void
263ptytty::set_utf8_mode (bool on)
264{
265#ifdef IUTF8
266 if (pty < 0)
267 return;
268
269 struct termios tio;
270
271 if (tcgetattr (pty, &tio) != -1)
272 { 372 }
273 tcflag_t new_cflag = tio.c_iflag;
274
275 if (on)
276 new_cflag |= IUTF8;
277 else
278 new_cflag &= ~IUTF8;
279
280 if (new_cflag != tio.c_iflag)
281 {
282 tio.c_iflag = new_cflag;
283 tcsetattr (pty, TCSANOW, &tio);
284 }
285 }
286#endif 373#endif
287}
288 374
289static struct ttyconf {
290 gid_t gid;
291 mode_t mode;
292
293 ttyconf ()
294 {
295#ifdef TTY_GID_SUPPORT
296 struct group *gr = getgrnam ("tty");
297
298 if (gr)
299 { /* change group ownership of tty to "tty" */
300 mode = S_IRUSR | S_IWUSR | S_IWGRP;
301 gid = gr->gr_gid;
302 }
303 else
304#endif /* TTY_GID_SUPPORT */
305 {
306 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
307 gid = 0;
308 }
309 }
310} ttyconf;
311
312ptytty_unix::ptytty_unix ()
313{
314 name = 0;
315#if UTMP_SUPPORT 375#if UTMP_SUPPORT
316 cmd_pid = 0; 376# if defined(HAVE_STRUCT_UTMP) && !defined(HAVE_UTMP_PID)
317#endif 377 int fd_stdin = dup (STDIN_FILENO);
318} 378 dup2 (tty, STDIN_FILENO);
319 379
320ptytty_unix::~ptytty_unix () 380 utmp_pos = ttyslot ();
321{
322#if UTMP_SUPPORT
323 logout ();
324#endif
325 put ();
326}
327 381
328void 382 dup2 (fd_stdin, STDIN_FILENO);
329ptytty_unix::put () 383 close (fd_stdin);
330{
331 chmod (name, RESTORE_TTY_MODE);
332 chown (name, 0, ttyconf.gid);
333
334 close_tty ();
335
336 if (pty >= 0)
337 close (pty);
338
339 free (name);
340
341 pty = tty = -1;
342 name = 0;
343}
344
345bool
346ptytty_unix::get ()
347{
348 /* get master (pty) */
349 if ((pty = get_pty (&tty, &name)) < 0)
350 return false;
351
352 fcntl (pty, F_SETFL, O_NONBLOCK);
353
354 /* get slave (tty) */
355 if (tty < 0)
356 {
357#ifndef NO_SETOWNER_TTYDEV
358 chown (name, getuid (), ttyconf.gid); /* fail silently */
359 chmod (name, ttyconf.mode);
360# ifdef HAVE_REVOKE
361 revoke (name);
362# endif 384# endif
363#endif 385#endif
364 386
365 if ((tty = get_tty (name)) < 0)
366 {
367 put ();
368 return false;
369 }
370 }
371
372 return true; 387 return true;
373} 388}
374 389
375#if PTYTTY_HELPER
376
377static int sock_fd = -1;
378static int helper_pid, owner_pid;
379
380struct command
381{
382 enum { get, login, destroy } type;
383
384 ptytty *id;
385
386 bool login_shell;
387 int cmd_pid;
388 char hostname[512]; // arbitrary, but should be plenty
389};
390
391struct ptytty_proxy : ptytty
392{
393 ptytty *id;
394
395 ptytty_proxy ()
396 : id(0)
397 {
398 }
399
400 ~ptytty_proxy ();
401
402 bool get ();
403 void login (int cmd_pid, bool login_shell, const char *hostname);
404};
405
406bool
407ptytty_proxy::get ()
408{
409 command cmd;
410
411 cmd.type = command::get;
412
413 write (sock_fd, &cmd, sizeof (cmd));
414
415 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
416 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
417
418 if (!id)
419 return false;
420
421 if ((pty = recv_fd (sock_fd)) < 0
422 || (tty = recv_fd (sock_fd)) < 0)
423 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
424
425 return true;
426}
427
428void
429ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
430{
431 command cmd;
432
433 cmd.type = command::login;
434 cmd.id = id;
435 cmd.cmd_pid = cmd_pid;
436 cmd.login_shell = login_shell;
437 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
438
439 write (sock_fd, &cmd, sizeof (cmd));
440}
441
442ptytty_proxy::~ptytty_proxy ()
443{
444 if (id)
445 {
446 command cmd;
447
448 cmd.type = command::destroy;
449 cmd.id = id;
450
451 write (sock_fd, &cmd, sizeof (cmd));
452 }
453}
454
455static
456void serve ()
457{
458 command cmd;
459 vector<ptytty *> ptys;
460
461 while (read (sock_fd, &cmd, sizeof (command)) == sizeof (command))
462 {
463 if (cmd.type == command::get)
464 {
465 // -> id ptyfd ttyfd
466 cmd.id = new ptytty_unix;
467
468 if (cmd.id->get ())
469 {
470 write (sock_fd, &cmd.id, sizeof (cmd.id));
471 ptys.push_back (cmd.id);
472
473 ptytty::send_fd (sock_fd, cmd.id->pty);
474 ptytty::send_fd (sock_fd, cmd.id->tty);
475 }
476 else
477 {
478 delete cmd.id;
479 cmd.id = 0;
480 write (sock_fd, &cmd.id, sizeof (cmd.id));
481 }
482 }
483 else if (cmd.type == command::login)
484 {
485#if UTMP_SUPPORT
486 if (find (ptys.begin (), ptys.end (), cmd.id))
487 {
488 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
489 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
490 }
491#endif
492 }
493 else if (cmd.type == command::destroy)
494 {
495 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
496
497 if (pty != ptys.end ())
498 {
499 delete *pty;
500 ptys.erase (pty);
501 }
502 }
503 else
504 break;
505 }
506
507 // destroy all ptys
508 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
509 delete *i;
510}
511
512void
513ptytty::use_helper ()
514{
515 int pid = getpid ();
516
517 if (sock_fd >= 0 && pid == owner_pid)
518 return;
519
520 owner_pid = pid;
521
522 int sv[2];
523
524 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
525 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
526
527 helper_pid = fork ();
528
529 if (helper_pid < 0)
530 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
531
532 if (helper_pid)
533 {
534 // client, process
535 sock_fd = sv[0];
536 close (sv[1]);
537 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
538 }
539 else
540 {
541 // server, pty-helper
542 sock_fd = sv[1];
543
544 chdir ("/");
545
546 for (int fd = 0; fd < 1023; fd++)
547 if (fd != sock_fd)
548 close (fd);
549
550 serve ();
551 _exit (EXIT_SUCCESS);
552 }
553}
554
555#endif
556
557ptytty *
558ptytty::create ()
559{
560#if PTYTTY_HELPER
561 if (helper_pid && getpid () == owner_pid)
562 // use helper process
563 return new ptytty_proxy;
564 else
565#endif
566 return new ptytty_unix;
567}
568
569void
570ptytty::init ()
571{
572 uid_t uid = getuid ();
573 gid_t gid = getgid ();
574
575 // before doing anything else, check for setuid/setgid operation,
576 // start the helper process and drop privileges
577 if (uid != geteuid ()
578 || gid != getegid ())
579 {
580#if PTYTTY_HELPER
581 use_helper ();
582#else
583 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
584#endif
585
586 drop_privileges ();
587 }
588}
589
590void
591ptytty::drop_privileges ()
592{
593 uid_t uid = getuid ();
594 gid_t gid = getgid ();
595
596 // drop privileges
597#if HAVE_SETRESUID
598 setresgid (gid, gid, gid);
599 setresuid (uid, uid, uid);
600#elif HAVE_SETREUID
601 setregid (gid, gid);
602 setreuid (uid, uid);
603#elif HAVE_SETUID
604 setgid (gid);
605 setuid (uid);
606#endif
607
608 if (uid != geteuid ()
609 || gid != getegid ())
610 ptytty_fatal ("unable to drop privileges, aborting.\n");
611}
612

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