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Revision 1.19 by root, Mon Jan 23 11:36:01 2006 UTC vs.
Revision 1.46 by sf-exg, Tue Dec 20 21:03:21 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 <cstdio>
33#include <cstring> 34#include <cstring>
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)
… …
56#endif 56#endif
57#ifdef TTY_GID_SUPPORT 57#ifdef TTY_GID_SUPPORT
58#include <grp.h> 58#include <grp.h>
59#endif 59#endif
60 60
61#include <cstdio>
62
63///////////////////////////////////////////////////////////////////////////// 61/////////////////////////////////////////////////////////////////////////////
64 62
65/* ------------------------------------------------------------------------- * 63/* ------------------------------------------------------------------------- *
66 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 64 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
67 * ------------------------------------------------------------------------- */ 65 * ------------------------------------------------------------------------- */
68/* 66/*
69 * Returns pty file descriptor, or -1 on failure 67 * Returns pty file descriptor, or -1 on failure
70 * If successful, ttydev is set to the name of the slave device. 68 * 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 69 * fd_tty _may_ also be set to an open fd to the slave device
72 */ 70 */
73#if defined(UNIX98_PTY) 71#if defined(UNIX98_PTY)
72
74static int 73 static int
75get_pty (int *fd_tty, char **ttydev) 74 get_pty (int *fd_tty, char **ttydev)
76{ 75 {
77 int pfd; 76 int pfd;
78 77
79# if defined(HAVE_GETPT) 78# if defined(HAVE_GETPT)
80 pfd = getpt(); 79 pfd = getpt ();
81# elif defined(HAVE_POSIX_OPENPT) 80# elif defined(HAVE_POSIX_OPENPT)
82 pfd = posix_openpt (O_RDWR); 81 pfd = posix_openpt (O_RDWR | O_NOCTTY);
83# else 82# else
83# ifdef _AIX
84 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0); 84 pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0);
85# else
86 pfd = open ("/dev/ptmx", O_RDWR | O_NOCTTY, 0);
87# endif
85# endif 88# endif
89
86 if (pfd >= 0) 90 if (pfd >= 0)
87 { 91 {
88 if (grantpt (pfd) == 0 /* change slave permissions */ 92 if (grantpt (pfd) == 0 /* change slave permissions */
89 && unlockpt (pfd) == 0) 93 && unlockpt (pfd) == 0)
94 {
90 { /* slave now unlocked */ 95 /* slave now unlocked */
91 *ttydev = strdup (ptsname (pfd)); /* get slave's name */ 96 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
92 return pfd; 97 return pfd;
93 } 98 }
94 99
95 close (pfd); 100 close (pfd);
96 } 101 }
97 102
98 return -1; 103 return -1;
99} 104 }
105
100#elif defined(HAVE_OPENPTY) 106#elif defined(HAVE_OPENPTY)
107
101static int 108 static int
102get_pty (int *fd_tty, char **ttydev) 109 get_pty (int *fd_tty, char **ttydev)
103{ 110 {
104 int pfd; 111 int pfd;
105 int res; 112 int res;
106 char tty_name[32]; 113
107
108 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 114 res = openpty (&pfd, fd_tty, NULL, NULL, NULL);
115
109 if (res != -1) 116 if (res != -1)
110 { 117 {
111 *ttydev = strdup (tty_name); 118 *ttydev = strdup (ttyname (*fd_tty));
112 return pfd; 119 return pfd;
113 } 120 }
114 121
115 return -1; 122 return -1;
116} 123 }
124
117#elif defined(HAVE__GETPTY) 125#elif defined(HAVE__GETPTY)
126
118static int 127 static int
119get_pty (int *fd_tty, char **ttydev) 128 get_pty (int *fd_tty, char **ttydev)
120{ 129 {
121 int pfd; 130 int pfd;
131 char *slave;
122 132
123 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 133 slave = _getpty (&pfd, O_RDWR | O_NOCTTY, 0622, 0);
124 if (*ttydev != NULL)
125 return pfd;
126 134
127 return -1; 135 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 { 136 {
137 *ttydev = strdup (ttyname (pfd)); 137 *ttydev = strdup (slave);
138 return pfd; 138 return pfd;
139 } 139 }
140 140
141 return -1; 141 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 } 142 }
154 143
155 return -1;
156}
157#else 144#else
145
158/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */ 146 /* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
159static int 147 static int
160get_pty (int *fd_tty, char **ttydev) 148 get_pty (int *fd_tty, char **ttydev)
161{ 149 {
162 int pfd; 150 int pfd;
163 int i; 151 int i;
164 char pty_name[32]; 152 char pty_name[32];
165 char tty_name[32]; 153 char tty_name[32];
166 const char *majors = "pqrstuvwxyzabcde"; 154 const char *majors = "pqrstuvwxyzabcde";
167 const char *minors = "0123456789abcdef"; 155 const char *minors = "0123456789abcdef";
156
168 for (i = 0; i < 256; i++) 157 for (i = 0; i < 256; i++)
169 { 158 {
170 snprintf(pty_name, 32, "/dev/pty%c%c", majors[i / 16], minors[i % 16]); 159 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]); 160 snprintf (tty_name, 32, "/dev/tty%c%c", majors[i / 16], minors[i % 16]);
161
172 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 162 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
173 { 163 {
174 snprintf(pty_name, 32, "/dev/ptyp%d", i); 164 snprintf (pty_name, 32, "/dev/ptyp%d", i);
175 snprintf(tty_name, 32, "/dev/ttyp%d", i); 165 snprintf (tty_name, 32, "/dev/ttyp%d", i);
176 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1) 166 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
177 continue; 167 continue;
178 } 168 }
169
179 if (access (tty_name, R_OK | W_OK) == 0) 170 if (access (tty_name, R_OK | W_OK) == 0)
180 { 171 {
181 *ttydev = strdup (tty_name); 172 *ttydev = strdup (tty_name);
182 return pfd; 173 return pfd;
183 } 174 }
184 175
185 close (pfd); 176 close (pfd);
186 } 177 }
187} 178
179 return -1;
180 }
181
188#endif 182#endif
189 183
190/*----------------------------------------------------------------------*/ 184/*----------------------------------------------------------------------*/
191/* 185/*
192 * Returns tty file descriptor, or -1 on failure 186 * Returns tty file descriptor, or -1 on failure
193 */ 187 */
194static int 188static int
195get_tty (char *ttydev) 189get_tty (char *ttydev)
196{ 190{
197 return open (ttydev, O_RDWR | O_NOCTTY, 0); 191 return open (ttydev, O_RDWR | O_NOCTTY, 0);
… …
202 * Make our tty a controlling tty so that /dev/tty points to us 196 * Make our tty a controlling tty so that /dev/tty points to us
203 */ 197 */
204static int 198static int
205control_tty (int fd_tty) 199control_tty (int fd_tty)
206{ 200{
201 int fd;
202
207 setsid (); 203 setsid ();
208 204
209#if defined(HAVE_DEV_PTMX) && defined(I_PUSH) 205#ifdef TIOCSCTTY
206 ioctl (fd_tty, TIOCSCTTY, NULL);
207#else
208 fd = open (ttyname (fd_tty), O_RDWR);
209 if (fd >= 0)
210 close (fd);
211#endif
212
213 fd = open ("/dev/tty", O_WRONLY);
214 if (fd < 0)
215 return -1; /* fatal */
216
217 close (fd);
218
219 return 0;
220}
221
222void
223ptytty::close_tty ()
224{
225 if (tty < 0)
226 return;
227
228 close (tty);
229 tty = -1;
230}
231
232bool
233ptytty::make_controlling_tty ()
234{
235 return control_tty (tty) >= 0;
236}
237
238void
239ptytty::set_utf8_mode (bool on)
240{
241#ifdef IUTF8
242 if (pty < 0)
243 return;
244
245 struct termios tio;
246
247 if (tcgetattr (pty, &tio) != -1)
248 {
249 tcflag_t new_cflag = tio.c_iflag;
250
251 if (on)
252 new_cflag |= IUTF8;
253 else
254 new_cflag &= ~IUTF8;
255
256 if (new_cflag != tio.c_iflag)
257 {
258 tio.c_iflag = new_cflag;
259 tcsetattr (pty, TCSANOW, &tio);
260 }
261 }
262#endif
263}
264
265static struct ttyconf {
266 gid_t gid;
267 mode_t mode;
268
269 ttyconf ()
270 {
271#ifdef TTY_GID_SUPPORT
272 struct group *gr = getgrnam ("tty");
273
274 if (gr)
275 {
276 /* change group ownership of tty to "tty" */
277 mode = S_IRUSR | S_IWUSR | S_IWGRP;
278 gid = gr->gr_gid;
279 }
280 else
281#endif /* TTY_GID_SUPPORT */
282 {
283 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
284 gid = 0;
285 }
286 }
287} ttyconf;
288
289ptytty_unix::ptytty_unix ()
290{
291 name = 0;
292#if UTMP_SUPPORT
293 cmd_pid = 0;
294#endif
295}
296
297ptytty_unix::~ptytty_unix ()
298{
299#if UTMP_SUPPORT
300 logout ();
301#endif
302 put ();
303}
304
305void
306ptytty_unix::put ()
307{
308 if (name)
309 {
310 chmod (name, RESTORE_TTY_MODE);
311 chown (name, 0, ttyconf.gid);
312 }
313
314 close_tty ();
315
316 if (pty >= 0)
317 close (pty);
318
319 free (name);
320
321 pty = tty = -1;
322 name = 0;
323}
324
325bool
326ptytty_unix::get ()
327{
328 /* get master (pty) */
329 if ((pty = get_pty (&tty, &name)) < 0)
330 return false;
331
332 /* get slave (tty) */
333 if (tty < 0)
334 {
335#ifndef NO_SETOWNER_TTYDEV
336 chown (name, getuid (), ttyconf.gid); /* fail silently */
337 chmod (name, ttyconf.mode);
338# ifdef HAVE_REVOKE
339 revoke (name);
340# endif
341#endif
342
343 if ((tty = get_tty (name)) < 0)
344 {
345 put ();
346 return false;
347 }
348 }
349
350#if defined(I_PUSH)
210 /* 351 /*
211 * Push STREAMS modules: 352 * Push STREAMS modules:
212 * ptem: pseudo-terminal hardware emulation module. 353 * ptem: pseudo-terminal hardware emulation module.
213 * ldterm: standard terminal line discipline. 354 * ldterm: standard terminal line discipline.
214 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module. 355 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module.
215 * 356 *
216 * After we push the STREAMS modules, the first open () on the slave side 357 * 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 358 * 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 359 * 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 360 * 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 361 * 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 362 * 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 363 * 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 364 * close () - on the master side which causes a hang up to be sent
225 * through - Geoff Wing 365 * through - Geoff Wing
226 */ 366 */
227# ifdef HAVE_ISASTREAM 367#if defined(HAVE_ISASTREAM) && defined(HAVE_STROPTS_H)
228 if (isastream (fd_tty) == 1) 368 if (isastream (tty) == 1)
229# endif 369# endif
230 { 370 {
231 ioctl (fd_tty, I_PUSH, "ptem"); 371 ioctl (tty, I_PUSH, "ptem");
232 ioctl (fd_tty, I_PUSH, "ldterm"); 372 ioctl (tty, I_PUSH, "ldterm");
233 ioctl (fd_tty, I_PUSH, "ttcompat"); 373 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 { 374 }
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 375#endif
289}
290 376
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 377#if UTMP_SUPPORT
318 cmd_pid = 0; 378# if defined(HAVE_STRUCT_UTMP) && !defined(HAVE_UTMP_PID)
319#endif 379 int fd_stdin = dup (STDIN_FILENO);
320} 380 dup2 (tty, STDIN_FILENO);
321 381
322ptytty_unix::~ptytty_unix () 382 utmp_pos = ttyslot ();
323{
324#if UTMP_SUPPORT
325 logout ();
326#endif
327 put ();
328}
329 383
330void 384 dup2 (fd_stdin, STDIN_FILENO);
331ptytty_unix::put () 385 close (fd_stdin);
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 386# endif
365#endif 387#endif
366 388
367 if ((tty = get_tty (name)) < 0)
368 {
369 put ();
370 return false;
371 }
372 }
373
374 return true; 389 return true;
375} 390}
376 391
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
411bool
412ptytty_proxy::get ()
413{
414 command cmd;
415
416 cmd.type = command::get;
417
418 write (sock_fd, &cmd, sizeof (cmd));
419
420 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
421 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
422
423 if (!id)
424 return false;
425
426 if ((pty = recv_fd (sock_fd)) < 0
427 || (tty = recv_fd (sock_fd)) < 0)
428 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
429
430 return true;
431}
432
433void
434ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
435{
436 command cmd;
437
438 cmd.type = command::login;
439 cmd.id = id;
440 cmd.cmd_pid = cmd_pid;
441 cmd.login_shell = login_shell;
442 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
443
444 write (sock_fd, &cmd, sizeof (cmd));
445}
446
447ptytty_proxy::~ptytty_proxy ()
448{
449 if (id)
450 {
451 command cmd;
452
453 cmd.type = command::destroy;
454 cmd.id = id;
455
456 write (sock_fd, &cmd, sizeof (cmd));
457 }
458}
459
460static
461void serve ()
462{
463 command cmd;
464 vector<ptytty *> ptys;
465
466 while (read (sock_fd, &cmd, sizeof (command)) == sizeof (command))
467 {
468 if (cmd.type == command::get)
469 {
470 // -> id ptyfd ttyfd
471 cmd.id = new ptytty_unix;
472
473 if (cmd.id->get ())
474 {
475 write (sock_fd, &cmd.id, sizeof (cmd.id));
476 ptys.push_back (cmd.id);
477
478 ptytty::send_fd (sock_fd, cmd.id->pty);
479 ptytty::send_fd (sock_fd, cmd.id->tty);
480 }
481 else
482 {
483 delete cmd.id;
484 cmd.id = 0;
485 write (sock_fd, &cmd.id, sizeof (cmd.id));
486 }
487 }
488 else if (cmd.type == command::login)
489 {
490#if UTMP_SUPPORT
491 if (find (ptys.begin (), ptys.end (), cmd.id) != ptys.end ())
492 {
493 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
494 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
495 }
496#endif
497 }
498 else if (cmd.type == command::destroy)
499 {
500 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
501
502 if (pty != ptys.end ())
503 {
504 delete *pty;
505 ptys.erase (pty);
506 }
507 }
508 else
509 break;
510 }
511
512 // destroy all ptys
513 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
514 delete *i;
515}
516
517void
518ptytty::use_helper ()
519{
520 int pid = getpid ();
521
522 if (sock_fd >= 0 && pid == owner_pid)
523 return;
524
525 owner_pid = pid;
526
527 int sv[2];
528
529 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
530 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
531
532#ifdef PTYTTY_REENTRANT
533 int lv[2];
534
535 if (socketpair (AF_UNIX, SOCK_STREAM, 0, lv))
536 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
537#endif
538
539 helper_pid = fork ();
540
541 if (helper_pid < 0)
542 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
543
544 if (helper_pid)
545 {
546 // client, process
547 sock_fd = sv[0];
548 close (sv[1]);
549 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
550#ifdef PTYTTY_REENTRANT
551 lock_fd = lv[0];
552 close (lv[1]);
553 fcntl (lock_fd, F_SETFD, FD_CLOEXEC);
554#endif
555 }
556 else
557 {
558 // server, pty-helper
559 sock_fd = sv[1];
560#ifdef PTYTTY_REENTRANT
561 lock_fd = lv[1];
562#endif
563
564 chdir ("/");
565
566 signal (SIGHUP, SIG_IGN);
567 signal (SIGTERM, SIG_IGN);
568 signal (SIGINT, SIG_IGN);
569 signal (SIGPIPE, SIG_IGN);
570
571 for (int fd = 0; fd < 1023; fd++)
572 if (fd != sock_fd && fd != lock_fd)
573 close (fd);
574
575 serve ();
576 _exit (EXIT_SUCCESS);
577 }
578}
579
580#endif
581
582ptytty *
583ptytty::create ()
584{
585#if PTYTTY_HELPER
586 if (helper_pid && getpid () == owner_pid)
587 // use helper process
588 return new ptytty_proxy;
589 else
590#endif
591 return new ptytty_unix;
592}
593
594void
595ptytty::init ()
596{
597 uid_t uid = getuid ();
598 gid_t gid = getgid ();
599
600 // before doing anything else, check for setuid/setgid operation,
601 // start the helper process and drop privileges
602 if (uid != geteuid ()
603 || gid != getegid ())
604 {
605#if PTYTTY_HELPER
606 use_helper ();
607#else
608 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
609#endif
610
611 drop_privileges ();
612 }
613}
614
615void
616ptytty::drop_privileges ()
617{
618 uid_t uid = getuid ();
619 gid_t gid = getgid ();
620
621 // drop privileges
622#if HAVE_SETRESUID
623 setresgid (gid, gid, gid);
624 setresuid (uid, uid, uid);
625#elif HAVE_SETREUID
626 setregid (gid, gid);
627 setreuid (uid, uid);
628#elif HAVE_SETUID
629 setgid (gid);
630 setuid (uid);
631#endif
632
633 if (uid != geteuid ()
634 || gid != getegid ())
635 ptytty_fatal ("unable to drop privileges, aborting.\n");
636}
637
638/////////////////////////////////////////////////////////////////////////////
639// C API
640
641#ifndef NO_C_API
642
643#define DEFINE_METHOD(retval, name, args1, args2) \
644extern "C" retval ptytty_ ## name args1 \
645{ return ((struct ptytty *)ptytty)->name args2; }
646
647DEFINE_METHOD(int,pty,(void *ptytty),)
648DEFINE_METHOD(int,tty,(void *ptytty),)
649DEFINE_METHOD(int,get,(void *ptytty),())
650DEFINE_METHOD(void,login,(void *ptytty, int cmd_pid, bool login_shell, const char *hostname),(cmd_pid,login_shell,hostname))
651
652DEFINE_METHOD(void,close_tty,(void *ptytty),())
653DEFINE_METHOD(int,make_controlling_tty,(void *ptytty),())
654DEFINE_METHOD(void,set_utf8_mode,(void *ptytty, int on),(on))
655
656#define DEFINE_STATIC(retval, name, args) \
657extern "C" retval ptytty_ ## name args \
658{ return ptytty::name args; }
659
660DEFINE_STATIC(void,drop_privileges,())
661DEFINE_STATIC(void,use_helper,())
662DEFINE_STATIC(void,init,())
663
664DEFINE_STATIC(void *,create,())
665
666void ptytty_delete (void *ptytty)
667{
668 delete (struct ptytty *)ptytty;
669}
670
671// send_fd, recv_fd not exposed
672
673#endif

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