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Comparing rxvt-unicode/src/ptytty.C (file contents):
Revision 1.38 by root, Tue Jan 17 11:53:07 2006 UTC vs.
Revision 1.57 by root, Sun Jan 22 12:21:47 2006 UTC

1// This file is part of libptytty. Do not make local modifications.
2// http://software.schmorp.de/pkg/libptytty
3
1/*--------------------------------*-C-*---------------------------------* 4/*----------------------------------------------------------------------*
2 * File: ptytty.C 5 * File: ptytty.C
3 *----------------------------------------------------------------------* 6 *----------------------------------------------------------------------*
4 * 7 *
5 * All portions of code are copyright by their respective author/s. 8 * All portions of code are copyright by their respective author/s.
6 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com> 9 * Copyright (c) 1999-2001 Geoff Wing <gcw@pobox.com>
7 * Copyright (c) 2004-2006 Marc Lehmann <pcg@goof.com> 10 * Copyright (c) 2004-2006 Marc Lehmann <pcg@goof.com>
11 * Copyright (c) 2006 Emanuele Giaquinta <e.giaquinta@glauco.it>
8 * 12 *
9 * 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
10 * 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
11 * the Free Software Foundation; either version 2 of the License, or 15 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version. 16 * (at your option) any later version.
… …
19 * 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
20 * along with this program; if not, write to the Free Software 24 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 *---------------------------------------------------------------------*/ 26 *---------------------------------------------------------------------*/
23 27
24#include "../config.h" /* NECESSARY */ 28#include "../config.h"
29
25#include "rxvt.h" 30#include "ptytty.h"
26 31
27# include <cstdlib> 32#include <cstdlib>
28# include <cstring> 33#include <cstring>
29 34
30#ifdef HAVE_SYS_TYPES_H
31# include <sys/types.h> 35#include <sys/types.h>
32#endif 36#include <sys/socket.h>
33#ifdef HAVE_UNISTD_H
34# include <unistd.h> 37#include <unistd.h>
35#endif
36#ifdef HAVE_FCNTL_H
37# include <fcntl.h> 38#include <fcntl.h>
38#endif 39
39#ifdef HAVE_SYS_IOCTL_H 40#ifdef HAVE_SYS_IOCTL_H
40# include <sys/ioctl.h> 41# include <sys/ioctl.h>
41#endif 42#endif
42#if defined(PTYS_ARE_PTMX) && defined(HAVE_SYS_STROPTS_H) 43#if defined(HAVE_DEV_PTMX) && defined(HAVE_SYS_STROPTS_H)
43# include <sys/stropts.h> /* for I_PUSH */ 44# include <sys/stropts.h> /* for I_PUSH */
44#endif 45#endif
45#ifdef HAVE_ISASTREAM 46#ifdef HAVE_ISASTREAM
46# include <stropts.h> 47# include <stropts.h>
47#endif 48#endif
… …
50#elif defined(HAVE_LIBUTIL_H) 51#elif defined(HAVE_LIBUTIL_H)
51# include <libutil.h> 52# include <libutil.h>
52#elif defined(HAVE_UTIL_H) 53#elif defined(HAVE_UTIL_H)
53# include <util.h> 54# include <util.h>
54#endif 55#endif
56#ifdef TTY_GID_SUPPORT
57#include <grp.h>
58#endif
55 59
56#include <cstdio> 60#include <cstdio>
57#include <grp.h>
58 61
59///////////////////////////////////////////////////////////////////////////// 62/////////////////////////////////////////////////////////////////////////////
60 63
61/* ------------------------------------------------------------------------- * 64/* ------------------------------------------------------------------------- *
62 * GET PSEUDO TELETYPE - MASTER AND SLAVE * 65 * GET PSEUDO TELETYPE - MASTER AND SLAVE *
… …
64/* 67/*
65 * Returns pty file descriptor, or -1 on failure 68 * Returns pty file descriptor, or -1 on failure
66 * 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.
67 * 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
68 */ 71 */
72#if defined(UNIX98_PTY)
69static int 73static int
70get_pty (int *fd_tty, char **ttydev) 74get_pty (int *fd_tty, char **ttydev)
71{ 75{
72 int pfd; 76 int pfd;
73 77
74#ifdef PTYS_ARE_OPENPTY 78# if defined(HAVE_GETPT)
75 char tty_name[sizeof "/dev/pts/????\0"]; 79 pfd = getpt();
80# elif defined(HAVE_POSIX_OPENPT)
81 pfd = posix_openpt (O_RDWR);
82# else
83 pfd = open (CLONE_DEVICE, O_RDWR | O_NOCTTY, 0);
84# endif
85 if (pfd >= 0)
86 {
87 if (grantpt (pfd) == 0 /* change slave permissions */
88 && unlockpt (pfd) == 0)
89 { /* slave now unlocked */
90 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
91 return pfd;
92 }
76 93
77 rxvt_privileges(RESTORE); 94 close (pfd);
95 }
96
97 return -1;
98}
99#elif defined(HAVE_OPENPTY)
100static int
101get_pty (int *fd_tty, char **ttydev)
102{
103 int pfd;
104 int res;
105 char tty_name[32];
106
78 int res = openpty (&pfd, fd_tty, tty_name, NULL, NULL); 107 res = openpty (&pfd, fd_tty, tty_name, NULL, NULL);
79 rxvt_privileges(IGNORE);
80
81 if (res != -1) 108 if (res != -1)
82 { 109 {
83 *ttydev = strdup (tty_name); 110 *ttydev = strdup (tty_name);
84 return pfd; 111 return pfd;
85 } 112 }
86#endif
87 113
88#ifdef PTYS_ARE__GETPTY 114 return -1;
115}
116#elif defined(HAVE__GETPTY)
117static int
118get_pty (int *fd_tty, char **ttydev)
119{
120 int pfd;
121
89 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0); 122 *ttydev = _getpty (&pfd, O_RDWR | O_NONBLOCK | O_NOCTTY, 0622, 0);
90 if (*ttydev != NULL) 123 if (*ttydev != NULL)
91 return pfd; 124 return pfd;
92#endif
93 125
94#if defined(HAVE_GRANTPT) && defined(HAVE_UNLOCKPT) 126 return -1;
95# if defined(PTYS_ARE_GETPT) || defined(PTYS_ARE_POSIX) || defined(PTYS_ARE_PTMX) 127}
128#elif defined(HAVE_DEV_PTC)
129static int
130get_pty (int *fd_tty, char **ttydev)
131{
132 int pfd;
96 133
97 {
98# ifdef PTYS_ARE_GETPT
99 pfd = getpt();
100# else
101# ifdef PTYS_ARE_POSIX
102 pfd = posix_openpt (O_RDWR);
103# else
104 pfd = open ("/dev/ptmx", O_RDWR | O_NOCTTY, 0);
105# endif
106# endif
107
108 if (pfd >= 0)
109 {
110 if (grantpt (pfd) == 0 /* change slave permissions */
111 && unlockpt (pfd) == 0)
112 { /* slave now unlocked */
113 *ttydev = strdup (ptsname (pfd)); /* get slave's name */
114 return pfd;
115 }
116 close (pfd);
117 }
118 }
119# endif
120#endif
121
122#ifdef PTYS_ARE_PTC
123 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0) 134 if ((pfd = open ("/dev/ptc", O_RDWR | O_NOCTTY, 0)) >= 0)
124 { 135 {
125 *ttydev = strdup (ttyname (pfd)); 136 *ttydev = strdup (ttyname (pfd));
126 return pfd; 137 return pfd;
127 } 138 }
128#endif
129 139
130#ifdef PTYS_ARE_CLONE 140 return -1;
141}
142#elif defined(HAVE_DEV_CLONE)
143static int
144get_pty (int *fd_tty, char **ttydev)
145{
146 int pfd;
147
131 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0) 148 if ((pfd = open ("/dev/ptym/clone", O_RDWR | O_NOCTTY, 0)) >= 0)
132 { 149 {
133 *ttydev = strdup (ptsname (pfd)); 150 *ttydev = strdup (ptsname (pfd));
134 return pfd; 151 return pfd;
135 } 152 }
136#endif
137
138#ifdef PTYS_ARE_NUMERIC
139 {
140 int idx;
141 char *c1, *c2;
142 char pty_name[] = "/dev/ptyp???";
143 char tty_name[] = "/dev/ttyp???";
144
145 c1 = &(pty_name[sizeof (pty_name) - 4]);
146 c2 = &(tty_name[sizeof (tty_name) - 4]);
147 for (idx = 0; idx < 256; idx++)
148 {
149 sprintf (c1, "%d", idx);
150 sprintf (c2, "%d", idx);
151 if (access (tty_name, F_OK) < 0)
152 {
153 idx = 256;
154 break;
155 }
156
157 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) >= 0)
158 {
159 if (access (tty_name, R_OK | W_OK) == 0)
160 {
161 *ttydev = strdup (tty_name);
162 return pfd;
163 }
164
165 close (pfd);
166 }
167 }
168 }
169#endif
170
171#ifdef PTYS_ARE_SEARCHED
172 {
173 const char *c1, *c2;
174 char pty_name[] = "/dev/pty??";
175 char tty_name[] = "/dev/tty??";
176
177# ifndef PTYCHAR1
178# define PTYCHAR1 "pqrstuvwxyz"
179# endif
180# ifndef PTYCHAR2
181# define PTYCHAR2 "0123456789abcdef"
182# endif
183
184 for (c1 = PTYCHAR1; *c1; c1++)
185 {
186 pty_name[ (sizeof (pty_name) - 3)] =
187 tty_name[ (sizeof (pty_name) - 3)] = *c1;
188 for (c2 = PTYCHAR2; *c2; c2++)
189 {
190 pty_name[ (sizeof (pty_name) - 2)] =
191 tty_name[ (sizeof (pty_name) - 2)] = *c2;
192 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) >= 0)
193 {
194 if (access (tty_name, R_OK | W_OK) == 0)
195 {
196 *ttydev = strdup (tty_name);
197 return pfd;
198 }
199
200 close (pfd);
201 }
202 }
203 }
204 }
205#endif
206 153
207 return -1; 154 return -1;
208} 155}
156#else
157/* Based on the code in openssh/openbsd-compat/bsd-openpty.c */
158static int
159get_pty (int *fd_tty, char **ttydev)
160{
161 int pfd;
162 int i;
163 char pty_name[32];
164 char tty_name[32];
165 const char *majors = "pqrstuvwxyzabcde";
166 const char *minors = "0123456789abcdef";
167 for (i = 0; i < 256; i++)
168 {
169 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]);
171 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
172 {
173 snprintf(pty_name, 32, "/dev/ptyp%d", i);
174 snprintf(tty_name, 32, "/dev/ttyp%d", i);
175 if ((pfd = open (pty_name, O_RDWR | O_NOCTTY, 0)) == -1)
176 continue;
177 }
178 if (access (tty_name, R_OK | W_OK) == 0)
179 {
180 *ttydev = strdup (tty_name);
181 return pfd;
182 }
183
184 close (pfd);
185 }
186}
187#endif
209 188
210/*----------------------------------------------------------------------*/ 189/*----------------------------------------------------------------------*/
211/* 190/*
212 * Returns tty file descriptor, or -1 on failure 191 * Returns tty file descriptor, or -1 on failure
213 */ 192 */
… …
222 * Make our tty a controlling tty so that /dev/tty points to us 201 * Make our tty a controlling tty so that /dev/tty points to us
223 */ 202 */
224static int 203static int
225control_tty (int fd_tty) 204control_tty (int fd_tty)
226{ 205{
227 int fd;
228
229 /* ---------------------------------------- */
230 setsid (); 206 setsid ();
231 207
232 /* ---------------------------------------- */
233# if defined(PTYS_ARE_PTMX) && defined(I_PUSH) 208#if defined(HAVE_DEV_PTMX) && defined(I_PUSH)
234 /* 209 /*
235 * Push STREAMS modules: 210 * Push STREAMS modules:
236 * ptem: pseudo-terminal hardware emulation module. 211 * ptem: pseudo-terminal hardware emulation module.
237 * ldterm: standard terminal line discipline. 212 * ldterm: standard terminal line discipline.
238 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module. 213 * ttcompat: V7, 4BSD and XENIX STREAMS compatibility module.
… …
246 * documentation is really unclear about whether it is any close () on 221 * documentation is really unclear about whether it is any close () on
247 * the master side or the last close () - i.e. a proper STREAMS dismantling 222 * the master side or the last close () - i.e. a proper STREAMS dismantling
248 * close () - on the master side which causes a hang up to be sent 223 * close () - on the master side which causes a hang up to be sent
249 * through - Geoff Wing 224 * through - Geoff Wing
250 */ 225 */
251# ifdef HAVE_ISASTREAM 226# ifdef HAVE_ISASTREAM
252 if (isastream (fd_tty) == 1) 227 if (isastream (fd_tty) == 1)
253# endif 228# endif
254 { 229 {
255 ioctl (fd_tty, I_PUSH, "ptem"); 230 ioctl (fd_tty, I_PUSH, "ptem");
256 ioctl (fd_tty, I_PUSH, "ldterm"); 231 ioctl (fd_tty, I_PUSH, "ldterm");
257 ioctl (fd_tty, I_PUSH, "ttcompat"); 232 ioctl (fd_tty, I_PUSH, "ttcompat");
258 } 233 }
259# endif 234#endif
260 /* ---------------------------------------- */ 235
261 fd = ioctl (fd_tty, TIOCSCTTY, NULL); 236 ioctl (fd_tty, TIOCSCTTY, NULL);
262 /* ---------------------------------------- */ 237
263 fd = open ("/dev/tty", O_WRONLY); 238 int fd = open ("/dev/tty", O_WRONLY);
264 if (fd < 0) 239 if (fd < 0)
265 return -1; /* fatal */ 240 return -1; /* fatal */
241
266 close (fd); 242 close (fd);
267 /* ---------------------------------------- */
268 243
269 return 0; 244 return 0;
270} 245}
271 246
272void 247void
273rxvt_ptytty::close_tty () 248ptytty::close_tty ()
274{ 249{
275 if (tty < 0) 250 if (tty < 0)
276 return; 251 return;
277 252
278 close (tty); 253 close (tty);
279 tty = -1; 254 tty = -1;
280} 255}
281 256
282bool 257bool
283rxvt_ptytty::make_controlling_tty () 258ptytty::make_controlling_tty ()
284{ 259{
285 return control_tty (tty) >= 0; 260 return control_tty (tty) >= 0;
286} 261}
287 262
288void 263void
289rxvt_ptytty::set_utf8_mode (bool on) 264ptytty::set_utf8_mode (bool on)
290{ 265{
291#ifdef IUTF8 266#ifdef IUTF8
292 if (pty < 0) 267 if (pty < 0)
293 return; 268 return;
294 269
… …
310 } 285 }
311 } 286 }
312#endif 287#endif
313} 288}
314 289
315/////////////////////////////////////////////////////////////////////////////
316
317#ifndef NO_SETOWNER_TTYDEV
318static struct ttyconf { 290static struct ttyconf {
319 gid_t gid; 291 gid_t gid;
320 mode_t mode; 292 mode_t mode;
321 293
322 ttyconf () 294 ttyconf ()
… …
331 } 303 }
332 else 304 else
333#endif /* TTY_GID_SUPPORT */ 305#endif /* TTY_GID_SUPPORT */
334 { 306 {
335 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH; 307 mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
336 gid = getgid (); 308 gid = 0;
337 } 309 }
338 } 310 }
339} ttyconf; 311} ttyconf;
340 312
341///////////////////////////////////////////////////////////////////////////// 313ptytty_unix::ptytty_unix ()
314{
315 name = 0;
316#if UTMP_SUPPORT
317 cmd_pid = 0;
318#endif
319}
320
321ptytty_unix::~ptytty_unix ()
322{
323#if UTMP_SUPPORT
324 logout ();
325#endif
326 put ();
327}
342 328
343void 329void
344rxvt_ptytty_unix::privileges (rxvt_privaction action) 330ptytty_unix::put ()
345{ 331{
346 if (!name || !*name) 332 chmod (name, RESTORE_TTY_MODE);
347 return; 333 chown (name, 0, ttyconf.gid);
348 334
349 rxvt_privileges (RESTORE); 335 close_tty ();
350 336
351 if (action == SAVE) 337 if (pty >= 0)
352 { 338 close (pty);
353# ifndef RESET_TTY_TO_COMMON_DEFAULTS
354 /* store original tty status for restoration rxvt_clean_exit () -- rgg 04/12/95 */
355 if (lstat (name, &savestat) < 0) /* you lose out */
356 ;
357 else
358# endif
359 {
360 saved = true;
361 chown (name, getuid (), ttyconf.gid); /* fail silently */
362 chmod (name, ttyconf.mode);
363# ifdef HAVE_REVOKE
364 revoke (name);
365# endif
366 }
367 }
368 else
369 { /* action == RESTORE */
370# ifndef RESET_TTY_TO_COMMON_DEFAULTS
371 if (saved)
372 {
373 chmod (name, savestat.st_mode);
374 chown (name, savestat.st_uid, savestat.st_gid);
375 }
376# else
377 chmod (name, (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH));
378 chown (name, 0, 0);
379# endif
380 339
381 } 340 free (name);
382 341
383 rxvt_privileges (IGNORE);
384}
385#endif
386
387rxvt_ptytty_unix::rxvt_ptytty_unix ()
388{
389 pty = tty = -1; 342 pty = tty = -1;
390 name = 0; 343 name = 0;
391#ifndef NO_SETOWNER_TTYDEV
392 saved = false;
393#endif
394#if UTMP_SUPPORT
395 cmd_pid = 0;
396#endif
397}
398
399rxvt_ptytty_unix::~rxvt_ptytty_unix ()
400{
401 logout ();
402 put ();
403}
404
405void
406rxvt_ptytty_unix::put ()
407{
408#ifndef NO_SETOWNER_TTYDEV
409 privileges (RESTORE);
410#endif
411
412 if (pty >= 0) close (pty);
413 close_tty ();
414 free (name);
415
416 pty = tty = -1;
417 name = 0;
418} 344}
419 345
420bool 346bool
421rxvt_ptytty_unix::get () 347ptytty_unix::get ()
422{ 348{
423 /* get master (pty) */ 349 /* get master (pty) */
424 if ((pty = get_pty (&tty, &name)) < 0) 350 if ((pty = get_pty (&tty, &name)) < 0)
425 return false; 351 return false;
426 352
… …
428 354
429 /* get slave (tty) */ 355 /* get slave (tty) */
430 if (tty < 0) 356 if (tty < 0)
431 { 357 {
432#ifndef NO_SETOWNER_TTYDEV 358#ifndef NO_SETOWNER_TTYDEV
433 privileges (SAVE); 359 chown (name, getuid (), ttyconf.gid); /* fail silently */
360 chmod (name, ttyconf.mode);
361# ifdef HAVE_REVOKE
362 revoke (name);
363# endif
434#endif 364#endif
435 365
436 if ((tty = get_tty (name)) < 0) 366 if ((tty = get_tty (name)) < 0)
437 { 367 {
438 put (); 368 put ();
… …
441 } 371 }
442 372
443 return true; 373 return true;
444} 374}
445 375
446/*----------------------- end-of-file (C source) -----------------------*/ 376#if PTYTTY_HELPER
447 377
378static int sock_fd = -1;
379static int helper_pid, owner_pid;
380
381struct command
382{
383 enum { get, login, destroy } type;
384
385 ptytty *id;
386
387 bool login_shell;
388 int cmd_pid;
389 char hostname[512]; // arbitrary, but should be plenty
390};
391
392struct ptytty_proxy : ptytty
393{
394 ptytty *id;
395
396 ptytty_proxy ()
397 : id(0)
398 {
399 }
400
401 ~ptytty_proxy ();
402
403 bool get ();
404 void login (int cmd_pid, bool login_shell, const char *hostname);
405};
406
407bool
408ptytty_proxy::get ()
409{
410 command cmd;
411
412 cmd.type = command::get;
413
414 write (sock_fd, &cmd, sizeof (cmd));
415
416 if (read (sock_fd, &id, sizeof (id)) != sizeof (id))
417 ptytty_fatal ("protocol error while creating pty using helper process, aborting.\n");
418
419 if (!id)
420 return false;
421
422 if ((pty = recv_fd (sock_fd)) < 0
423 || (tty = recv_fd (sock_fd)) < 0)
424 ptytty_fatal ("protocol error while reading pty/tty fds from helper process, aborting.\n");
425
426 return true;
427}
428
429void
430ptytty_proxy::login (int cmd_pid, bool login_shell, const char *hostname)
431{
432 command cmd;
433
434 cmd.type = command::login;
435 cmd.id = id;
436 cmd.cmd_pid = cmd_pid;
437 cmd.login_shell = login_shell;
438 strncpy (cmd.hostname, hostname, sizeof (cmd.hostname));
439
440 write (sock_fd, &cmd, sizeof (cmd));
441}
442
443ptytty_proxy::~ptytty_proxy ()
444{
445 if (id)
446 {
447 command cmd;
448
449 cmd.type = command::destroy;
450 cmd.id = id;
451
452 write (sock_fd, &cmd, sizeof (cmd));
453 }
454}
455
456static
457void serve ()
458{
459 command cmd;
460 vector<ptytty *> ptys;
461
462 while (read (sock_fd, &cmd, sizeof (command)) == sizeof (command))
463 {
464 if (cmd.type == command::get)
465 {
466 // -> id ptyfd ttyfd
467 cmd.id = new ptytty_unix;
468
469 if (cmd.id->get ())
470 {
471 write (sock_fd, &cmd.id, sizeof (cmd.id));
472 ptys.push_back (cmd.id);
473
474 ptytty::send_fd (sock_fd, cmd.id->pty);
475 ptytty::send_fd (sock_fd, cmd.id->tty);
476 }
477 else
478 {
479 delete cmd.id;
480 cmd.id = 0;
481 write (sock_fd, &cmd.id, sizeof (cmd.id));
482 }
483 }
484 else if (cmd.type == command::login)
485 {
486#if UTMP_SUPPORT
487 if (find (ptys.begin (), ptys.end (), cmd.id))
488 {
489 cmd.hostname[sizeof (cmd.hostname) - 1] = 0;
490 cmd.id->login (cmd.cmd_pid, cmd.login_shell, cmd.hostname);
491 }
492#endif
493 }
494 else if (cmd.type == command::destroy)
495 {
496 vector<ptytty *>::iterator pty = find (ptys.begin (), ptys.end (), cmd.id);
497
498 if (pty != ptys.end ())
499 {
500 delete *pty;
501 ptys.erase (pty);
502 }
503 }
504 else
505 break;
506 }
507
508 // destroy all ptys
509 for (vector<ptytty *>::iterator i = ptys.end (); i-- > ptys.begin (); )
510 delete *i;
511}
512
513void
514ptytty::use_helper ()
515{
516 int pid = getpid ();
517
518 if (sock_fd >= 0 && pid == owner_pid)
519 return;
520
521 owner_pid = pid;
522
523 int sv[2];
524
525 if (socketpair (AF_UNIX, SOCK_STREAM, 0, sv))
526 ptytty_fatal ("could not create socket to communicate with pty/sessiondb helper, aborting.\n");
527
528 helper_pid = fork ();
529
530 if (helper_pid < 0)
531 ptytty_fatal ("could not create pty/sessiondb helper process, aborting.\n");
532
533 if (helper_pid)
534 {
535 // client, process
536 sock_fd = sv[0];
537 close (sv[1]);
538 fcntl (sock_fd, F_SETFD, FD_CLOEXEC);
539 }
540 else
541 {
542 // server, pty-helper
543 sock_fd = sv[1];
544
545 chdir ("/");
546
547 for (int fd = 0; fd < 1023; fd++)
548 if (fd != sock_fd)
549 close (fd);
550
551 serve ();
552 _exit (EXIT_SUCCESS);
553 }
554}
555
556#endif
557
558ptytty *
559ptytty::create ()
560{
561#if PTYTTY_HELPER
562 if (helper_pid && getpid () == owner_pid)
563 // use helper process
564 return new ptytty_proxy;
565 else
566#endif
567 return new ptytty_unix;
568}
569
570void
571ptytty::init ()
572{
573 uid_t uid = getuid ();
574 gid_t gid = getgid ();
575
576 // before doing anything else, check for setuid/setgid operation,
577 // start the helper process and drop privileges
578 if (uid != geteuid ()
579 || gid != getegid ())
580 {
581#if PTYTTY_HELPER
582 use_helper ();
583#else
584 ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n");
585#endif
586
587 drop_privileges ();
588 }
589}
590
591void
592ptytty::drop_privileges ()
593{
594 uid_t uid = getuid ();
595 gid_t gid = getgid ();
596
597 // drop privileges
598#if HAVE_SETRESUID
599 setresgid (gid, gid, gid);
600 setresuid (uid, uid, uid);
601#elif HAVE_SETREUID
602 setregid (gid, gid);
603 setreuid (uid, uid);
604#elif HAVE_SETUID
605 setgid (gid);
606 setuid (uid);
607#endif
608
609 if (uid != geteuid ()
610 || gid != getegid ())
611 ptytty_fatal ("unable to drop privileges, aborting.\n");
612}
613

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