1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2014, 2015 Shruti V Sampat <shrutisampat@gmail.com>
23 */
24
25 /*
26 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 */
29
30 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
31 /* All Rights Reserved */
32
33 /*
34 * Portions of such source code were derived from Berkeley 4.3 BSD
35 * under license from the Regents of the University of California.
36 */
37
38 /*
39 * utmpd - utmp daemon
40 *
41 * This program receives requests from pututxline(3)
42 * via a named pipe to watch the process to make sure it cleans up
43 * its utmpx entry on termination.
44 * The program keeps a list of procs
45 * and uses poll() on their /proc files to detect termination.
46 * Also the program periodically scans the /etc/utmpx file for
47 * processes that aren't in the table so they can be watched.
48 *
49 * If utmpd doesn't hear back over the pipe from pututline(3) that
50 * the process has removed its entry it cleans the entry when the
51 * the process terminates.
52 * The AT&T Copyright above is there since we borrowed the pipe
53 * mechanism from init(1m).
54 */
55
56
57 #include <sys/types.h>
58 #include <signal.h>
59 #include <stdio.h>
60 #include <stdio_ext.h>
61 #include <unistd.h>
62 #include <utmpx.h>
63 #include <errno.h>
64 #include <termio.h>
65 #include <sys/termios.h>
66 #include <sys/tty.h>
67 #include <ctype.h>
68 #include <sys/stat.h>
69 #include <sys/statvfs.h>
70 #include <fcntl.h>
71 #include <time.h>
72 #include <sys/stropts.h>
73 #include <wait.h>
74 #include <syslog.h>
75 #include <stdlib.h>
76 #include <string.h>
77 #include <poll.h>
78 #include <deflt.h>
79 #include <procfs.h>
80 #include <sys/resource.h>
81 #include <limits.h>
82
83 #define dprintf(x) if (Debug) (void) printf x
84
85 /*
86 * Memory allocation keyed off MAX_FDS
87 */
88 #define MAX_FDS 4064 /* Maximum # file descriptors */
89 #define EXTRA_MARGIN 32 /* Allocate this many more FDS over Max_Fds */
90 /*
91 * MAX_POLLNV & RESETS - paranoia to cover an error case that might not exist
92 */
93 #define MAX_POLL_ERRS 1024 /* Count of bad errors */
94 #define MAX_RESETS 1024 /* Maximum times to reload tables */
95 #define POLL_TIMEOUT 300 /* Default Timeout for poll() in seconds */
96 #define CLEANIT 1 /* Used by rem_pid() */
97 #define DONT_CLEAN 0 /* Used by rem_pid() */
98 #define UTMP_DEFAULT "/etc/default/utmpd"
99 #define WARN_TIME 3600 /* seconds between utmp checks */
100 #define WTMPX_UFREQ 60 /* seconds between updating WTMPX's atime */
101
102
103 /*
104 * The pidrec structure describes the data shipped down the pipe to
105 * us from the pututxline() library in
106 * lib/libc/port/gen/getutx.c
107 */
108
109 /*
110 * pd_type's
111 */
112 #define ADDPID 1
113 #define REMPID 2
114
115 struct pidrec {
116 int pd_type; /* Command type */
117 pid_t pd_pid; /* pid to add or remove */
118 };
119
120
121 /*
122 * Since this program uses poll(2) and poll takes an array of file descriptors
123 * as an argument we maintain our data in tables.
124 * One table is the file descriptor array for poll, another parallel
125 * array is a table which contains the process ID of the corresponding
126 * open fd. These tables are kept sorted by process ID for quick lookups.
127 */
128
129 struct pidentry {
130 pid_t pl_pid; /* pid to watch for */
131 int pl_status; /* Exit status of proc */
132 };
133
134 static struct pidentry *pidtable = NULL;
135
136 static pollfd_t *fdtable = NULL;
137
138 static int pidcnt = 0; /* Number of procs being watched */
139 static char *prog_name; /* To save the invocation name away */
140 static char *UTMPPIPE_DIR = "/var/run";
141 static char *UTMPPIPE = "/var/run/utmppipe";
142 static int Pfd = -1; /* File descriptor of named pipe */
143 static int Poll_timeout = POLL_TIMEOUT;
144 static int WTMPXfd = -1; /* File descriptor of WTMPX_FILE */
145 static int WTMPX_ufreq = WTMPX_UFREQ;
146 static int Debug = 0; /* Set by command line argument */
147 static int Max_fds = MAX_FDS;
148
149 /*
150 * This program has three main components plus utilities and debug routines
151 * Receiver - receives the process ID or process for us to watch.
152 * (Uses a named pipe to get messages)
153 * Watcher - Use poll(2) to watch for processes to die so they
154 * can be cleaned up (get marked as DEAD_PROCESS)
155 * Scanner - periodically scans the utmpx file for stale entries
156 * or live entries that we don't know about.
157 */
158
159 static int wait_for_pids(); /* Watcher - uses poll */
160 static void scan_utmps(); /* Scanner, reads utmpx file */
161 static void drain_pipe(); /* Receiver - reads mesgs over UTMPPIPE */
162 static void setup_pipe(); /* For setting up receiver */
163
164 static void add_pid(); /* Adds a process to the table */
165 static void rem_pid(); /* Removes a process from the table */
166 static int find_pid(); /* Finds a process in the table */
167 static int proc_to_fd(); /* Takes a pid and returns an fd for its proc */
168 static void load_tables(); /* Loads up the tables the first time around */
169 static int pidcmp(); /* For sorting pids */
170
171 static void clean_entry(); /* Removes entry from our table and calls ... */
172 static void clean_utmpx_ent(); /* Cleans a utmpx entry */
173
174 static void fatal() __NORETURN; /* Prints error message and calls exit */
175 static void nonfatal(); /* Prints error message */
176 static void print_tables(); /* Prints out internal tables for Debug */
177 static int proc_is_alive(pid_t pid); /* Check if a process is alive */
178 static void warn_utmp(void);
179
180 /* Validate defaults from file and assign */
181 static int validate_default(char *defp, int *flag);
182
183 /*
184 * main() - Main does basic setup and calls wait_for_pids() to do the work
185 */
186
187 int
main(int argc,char * argv[])188 main(int argc, char *argv[])
189 {
190 char *defp;
191 struct rlimit rlim;
192 int i;
193 time_t curtime, now;
194 char msg[256];
195
196 prog_name = argv[0]; /* Save invocation name */
197
198 if (getuid() != 0) {
199 (void) fprintf(stderr,
200 "You must be root to run this program\n");
201 fatal("You must be root to run this program");
202 }
203
204 if (argc > 1) {
205 if ((argc == 2 && (int)strlen(argv[1]) >= 2) &&
206 (argv[1][0] == '-' && argv[1][1] == 'd')) {
207 Debug = 1;
208 } else {
209 (void) fprintf(stderr,
210 "%s: Wrong number of arguments\n", prog_name);
211 (void) fprintf(stderr,
212 "Usage: %s [-debug]\n", prog_name);
213 exit(2);
214 }
215 }
216
217 /*
218 * Read defaults file for poll timeout, WTMPX update frequency
219 * and maximum number of processes to monitor.
220 */
221 if (defopen(UTMP_DEFAULT) == 0) {
222 if ((defp = defread("SCAN_PERIOD=")) != NULL)
223 if (validate_default(defp, &Poll_timeout) == -1) {
224 (void) snprintf(msg, sizeof (msg), "SCAN_PERIOD"
225 " should be a positive integer, found %s",
226 defp);
227 nonfatal(msg);
228 }
229 dprintf(("Poll timeout set to %d\n", Poll_timeout));
230
231 if ((defp = defread("WTMPX_UPDATE_FREQ=")) != NULL)
232 if (validate_default(defp, &WTMPX_ufreq) == -1) {
233 (void) snprintf(msg, sizeof (msg),
234 "WTMPX_UPDATE_FREQ should be a positive "
235 "integer, found %s", defp);
236 nonfatal(msg);
237 }
238 dprintf(("WTMPX update frequency set to %d\n", WTMPX_ufreq));
239
240 /*
241 * Paranoia - if polling on large number of FDs is expensive /
242 * buggy the number can be set lower in the field.
243 */
244 if ((defp = defread("MAX_FDS=")) != NULL)
245 if (validate_default(defp, &Max_fds) == -1) {
246 (void) snprintf(msg, sizeof (msg), "MAX_FDS "
247 "should be a positive integer, found %s",
248 defp);
249 nonfatal(msg);
250 }
251 dprintf(("Max fds set to %d\n", Max_fds));
252 (void) defopen((char *)NULL);
253 }
254
255 if (Debug == 0) {
256 /*
257 * Daemonize ourselves
258 */
259 if (fork()) {
260 exit(0);
261 }
262 (void) close(0);
263 (void) close(1);
264 (void) close(2);
265 /*
266 * We open these to avoid accidentally writing to a proc file
267 */
268 (void) open("/dev/null", O_RDONLY);
269 (void) open("/dev/null", O_WRONLY);
270 (void) open("/dev/null", O_WRONLY);
271 (void) setsid(); /* release process from tty */
272 }
273
274 openlog(prog_name, LOG_PID, LOG_DAEMON); /* For error messages */
275 warn_utmp(); /* check to see if utmp came back by accident */
276
277 /*
278 * Allocate the pidtable and fdtable. An earlier version did
279 * this as we go, but this is simpler.
280 */
281 if ((pidtable = malloc(Max_fds * sizeof (struct pidentry))) == NULL)
282 fatal("Malloc failed");
283 if ((fdtable = malloc(Max_fds * sizeof (pollfd_t))) == NULL)
284 fatal("Malloc failed");
285
286 /*
287 * Up the limit on FDs
288 */
289 if (getrlimit(RLIMIT_NOFILE, &rlim) == 0) {
290 rlim.rlim_cur = Max_fds + EXTRA_MARGIN + 1;
291 rlim.rlim_max = Max_fds + EXTRA_MARGIN + 1;
292 if (setrlimit(RLIMIT_NOFILE, &rlim) != 0) {
293 fatal("Out of File Descriptors");
294 }
295 } else
296 fatal("getrlimit returned failure");
297
298 (void) enable_extended_FILE_stdio(-1, -1);
299
300 if ((WTMPXfd = open(WTMPX_FILE, O_RDONLY)) < 0)
301 nonfatal("WARNING: unable to open " WTMPX_FILE " for update.");
302
303 /*
304 * Loop here scanning the utmpx file and waiting for processes
305 * to terminate. Most of the activity is directed out of wait_for_pids.
306 * If wait_for_pids fails we reload the table and try again.
307 */
308
309 curtime = time(NULL);
310 dprintf(("utmp warning timer set to %d seconds\n", WARN_TIME));
311
312 for (i = 0; i < MAX_RESETS; i++) {
313 load_tables();
314 while (wait_for_pids() == 1) {
315 now = time(NULL);
316 if ((now - curtime) >= WARN_TIME) {
317 dprintf(("utmp warning timer expired\n"));
318 warn_utmp();
319 curtime = now;
320 }
321 }
322 }
323
324 (void) close(WTMPXfd);
325
326 /*
327 * We only get here if we had a bunch of resets - so give up
328 */
329 fatal("Too many resets, giving up");
330 return (1);
331 }
332
333 /*
334 * load_tables() - Designed to be called repeatedly if we need to
335 * restart things. Zeros the pidcount, and loads
336 * the tables by scanning utmpx
337 */
338
339 static void
load_tables()340 load_tables()
341 {
342 int i;
343
344 dprintf(("Load tables\n"));
345
346 /*
347 * Close any open files.
348 */
349 for (i = 0; i < pidcnt; i++)
350 (void) close(fdtable[i].fd);
351
352 pidcnt = 0;
353 Pfd = -1;
354 setup_pipe(); /* Setup the pipe to receive messages */
355 scan_utmps(); /* Read in USER procs entries to watch */
356 }
357
358
359 /*
360 * *** The Watcher ***
361 *
362 * Wait_for_pids - wait for the termination of a process in the table.
363 * Returns 1 on normal exist, 0 on failure.
364 */
365
366 static int
wait_for_pids()367 wait_for_pids()
368 {
369 register struct pollfd *pfd;
370 register int i;
371 pid_t pid;
372 int ret_val = 0;
373 int timeout;
374 static time_t last_timeout = 0;
375 static int bad_error = 0; /* Count of POLL errors */
376
377 /*
378 * First time through we initialize last_timeout to now.
379 */
380 if (last_timeout == 0)
381 last_timeout = time(NULL);
382
383 /*
384 * Recalculate timeout - checking to see if time expired.
385 */
386
387 if ((timeout = Poll_timeout - (time(NULL) - last_timeout)) <= 0) {
388 timeout = Poll_timeout;
389 last_timeout = time(NULL);
390 scan_utmps();
391 }
392
393 fdtable[0].events = POLLRDNORM;
394
395 for (i = 0; i < (timeout / WTMPX_ufreq); i++) {
396
397 /*
398 * Loop here while getting EAGAIN
399 */
400
401 while ((ret_val = poll(fdtable, pidcnt, WTMPX_ufreq*1000)) < 0)
402 if (errno == EAGAIN)
403 (void) sleep(2);
404 else
405 fatal("poll");
406 /*
407 * The results of pread(2) are discarded; we only want
408 * to update the access time of WTMPX_FILE.
409 * Periodically touching WTMPX helps determine when the
410 * OS became unavailable when the OS boots again .
411 * See PSARC 2004/462 for more information.
412 */
413
414 (void) pread(WTMPXfd, (void *)&pid, sizeof (pid), 0);
415
416 if (ret_val) /* file descriptor(s) need attention */
417 break;
418 }
419
420 /*
421 * If ret_val == 0 the poll timed out - reset last_time and
422 * call scan_utmps
423 */
424 if (ret_val == 0) {
425 last_timeout = time(NULL);
426 scan_utmps();
427 return (1);
428 }
429
430 /*
431 * Check the pipe file descriptor
432 */
433 if (fdtable[0].revents & POLLRDNORM) {
434 drain_pipe();
435 fdtable[0].revents = 0;
436 ret_val--;
437 }
438
439 (void) sleep(5); /* Give parents time to cleanup children */
440
441 /*
442 * We got here because the status of one of the pids that
443 * we are polling on has changed, so search the table looking
444 * for the entry.
445 *
446 * The table is scanned backwards so that entries can be removed
447 * while we go since the table is compacted from high down to low
448 */
449 for (i = pidcnt - 1; i > 0; i--) {
450 /*
451 * Break out of the loop if we've processed all the entries.
452 */
453 if (ret_val == 0)
454 break;
455
456 pfd = &fdtable[i];
457
458 if (pfd->fd < 0) {
459 rem_pid((pid_t)0, i, DONT_CLEAN);
460 continue;
461 }
462 /*
463 * POLLHUP - Process terminated
464 */
465 if (pfd->revents & POLLHUP) {
466 psinfo_t psinfo;
467
468 if (pread(pfd->fd, &psinfo, sizeof (psinfo), (off_t)0)
469 != sizeof (psinfo)) {
470 dprintf(("! %d: terminated, status 0x%.4x\n", \
471 (int)pidtable[i].pl_pid, psinfo.pr_wstat));
472 pidtable[i].pl_status = psinfo.pr_wstat;
473
474 } else {
475 dprintf(("! %d: terminated\n", \
476 (int)pidtable[i].pl_pid));
477 pidtable[i].pl_status = 0;
478 }
479 /*
480 * PID gets removed when terminated only
481 */
482 rem_pid((pid_t)0, i, CLEANIT);
483 ret_val--;
484 continue;
485 }
486 /*
487 * POLLNVAL and POLLERR
488 * These error's shouldn't occurr but until their fixed
489 * we perform some simple error recovery.
490 */
491 if (pfd->revents & (POLLNVAL|POLLERR)) {
492 dprintf(("Poll Err = %d pid = %d i = %d\n", \
493 pfd->revents, (int)pidtable[i].pl_pid, i));
494
495 pid = pidtable[i].pl_pid; /* Save pid for below */
496 /*
497 * If its POLLNVAL we just remove the process for
498 * now, it will get picked up in the next scan.
499 * POLLERR pids get re-added after being deleted.
500 */
501 if (pfd->revents & POLLNVAL) {
502 rem_pid((pid_t)0, i, DONT_CLEAN);
503 } else { /* Else... POLLERR */
504 rem_pid((pid_t)0, i, DONT_CLEAN);
505 add_pid(pid);
506 }
507
508 if (bad_error++ > MAX_POLL_ERRS) {
509 bad_error = 0;
510 return (0); /* 0 Indicates severe error */
511 }
512 ret_val--;
513 continue;
514 }
515
516 /*
517 * No more bits should be set in revents but check anyway
518 */
519 if (pfd->revents != 0) {
520 dprintf(("%d: unknown err %d\n", \
521 (int)pidtable[i].pl_pid, pfd->revents));
522
523 rem_pid((pid_t)0, i, DONT_CLEAN);
524 ret_val--;
525
526 if (bad_error++ > MAX_POLL_ERRS) {
527 bad_error = 0;
528 return (0); /* 0 Indicates severe error */
529 }
530 return (1);
531 }
532 }
533 return (1); /* 1 Indicates Everything okay */
534 }
535
536 /*
537 * *** The Scanner ***
538 *
539 * scan_utmps() - Scan the utmpx file.
540 * For each USER_PROCESS check
541 * if its alive or dead. If alive and its not in
542 * our table to be watched, put it there. If its
543 * dead, remove it from our table and clean it up.
544 */
545
546 static void
scan_utmps()547 scan_utmps()
548 {
549 struct utmpx *utmpx;
550 int i;
551
552 dprintf(("Scan utmps\n"));
553 /*
554 * Scan utmpx.
555 */
556 setutxent();
557 while ((utmpx = getutxent()) != NULL) {
558 if (utmpx->ut_type == USER_PROCESS) {
559 /*
560 * Is the process alive?
561 */
562 if (proc_is_alive(utmpx->ut_pid)) {
563 /*
564 * Yes, the process is alive, so add it if we
565 * don't have it in our table.
566 */
567 if (find_pid(utmpx->ut_pid, &i) == 0)
568 add_pid(utmpx->ut_pid); /* No, add it */
569 } else {
570 /*
571 * No, the process is dead, so remove it if its
572 * in our table, otherwise just clean it.
573 */
574 if (find_pid(utmpx->ut_pid, &i) == 1)
575 rem_pid(utmpx->ut_pid, i, CLEANIT);
576 else
577 clean_utmpx_ent(utmpx);
578 }
579 }
580 }
581 /*
582 * Close it to flush the buffer.
583 */
584 endutxent();
585 }
586
587
588 /*
589 * *** Receiver Routines ***
590 */
591
592 /*
593 * setup_pipe - Set up the pipe to read pids over
594 */
595
596 static void
setup_pipe()597 setup_pipe()
598 {
599
600 struct statvfs statvfs_buf;
601 /*
602 * This code & comments swiped from init and left stock since it works
603 */
604
605 if (Pfd < 0) {
606 if ((statvfs(UTMPPIPE_DIR, &statvfs_buf) == 0) &&
607 ((statvfs_buf.f_flag & ST_RDONLY) == 0)) {
608 (void) unlink(UTMPPIPE);
609 (void) mknod(UTMPPIPE, S_IFIFO | 0600, 0);
610 }
611 Pfd = open(UTMPPIPE, O_RDWR | O_NDELAY);
612 }
613 if (Pfd < 0)
614 nonfatal(UTMPPIPE);
615 /*
616 * This code from init modified to be poll based instead of SIGPOLL,
617 * signal based.
618 */
619
620 if (Pfd >= 0) {
621 /*
622 * Read pipe in message discard mode. When read reads a
623 * pidrec size record, the remainder of the message will
624 * be discarded. Though there shouldn't be any it will
625 * help resynch if someone else wrote some garbage.
626 */
627 (void) ioctl(Pfd, I_SRDOPT, RMSGD);
628 }
629
630 /*
631 * My code. We use slot 0 in the table to hold the fd of the pipe
632 */
633 add_pid(0); /* Proc 0 guaranteed to get slot 0 */
634 fdtable[0].fd = Pfd; /* Pfd could be -1, should be okay */
635 fdtable[0].events = POLLRDNORM;
636 }
637
638 /*
639 * drain_pipe() - The receiver routine that reads the pipe
640 */
641
642 static void
drain_pipe()643 drain_pipe()
644 {
645 struct pidrec prec;
646 register struct pidrec *p = ≺
647 int bytes_read;
648 int i;
649
650 for (;;) {
651 /*
652 * Important Note: Either read will really fail (in which case
653 * return is all we can do) or will get EAGAIN (Pfd was opened
654 * O_NDELAY), in which case we also want to return.
655 */
656
657 if ((bytes_read = read(Pfd, p, sizeof (struct pidrec))) !=
658 sizeof (struct pidrec)) {
659 /*
660 * Something went wrong reading, so read until pipe
661 * is empty
662 */
663 if (bytes_read > 0)
664 while (read(Pfd, p, sizeof (struct pidrec)) > 0)
665 ;
666 return;
667 }
668
669 dprintf(("drain_pipe: Recd command %d, pid %d\n",
670 p->pd_type, (int)p->pd_pid));
671 switch (p->pd_type) {
672 case ADDPID:
673 /*
674 * Check if we already have the process, adding it
675 * if we don't.
676 */
677 if (find_pid(p->pd_pid, &i) == 0)
678 add_pid(p->pd_pid);
679 break;
680
681 case REMPID:
682 rem_pid(p->pd_pid, -1, DONT_CLEAN);
683 break;
684 default:
685 nonfatal("Bad message on utmppipe\n");
686 break;
687 }
688 }
689 }
690
691
692 /*
693 * *** Utilities for add and removing entries in the tables ***
694 */
695
696 /*
697 * add_pid - add a pid to the fd table and the pidtable.
698 * these tables are sorted tables for quick lookups.
699 *
700 */
701 static void
add_pid(pid_t pid)702 add_pid(pid_t pid)
703 {
704 int fd = 0;
705 int i = 0, move_amt;
706 int j;
707 static int first_time = 1;
708
709 /*
710 * Check to see if the pid is already in our table, or being passed
711 * pid zero.
712 */
713 if (pidcnt != 0 && (find_pid(pid, &j) == 1 || pid == 0))
714 return;
715
716 if (pidcnt >= Max_fds) {
717 if (first_time == 1) {
718 /*
719 * Print this error only once
720 */
721 nonfatal("File Descriptor limit exceeded");
722 first_time = 0;
723 }
724 return;
725 }
726 /*
727 * Open the /proc file checking if there's still a valid proc file.
728 */
729 if (pid != 0 && (fd = proc_to_fd(pid)) == -1) {
730 /*
731 * No so the process died before we got to watch for him
732 */
733 return;
734 }
735
736 /*
737 * We only do this code if we're not putting in the first element
738 * Which we know will be for proc zero which is used by setup_pipe
739 * for its pipe fd.
740 */
741 if (pidcnt != 0) {
742 for (i = 0; i < pidcnt; i++) {
743 if (pid <= pidtable[i].pl_pid)
744 break;
745 }
746
747 /*
748 * Handle the case where we're not sticking our entry on the
749 * the end, or overwriting an existing entry.
750 */
751 if (i != pidcnt && pid != pidtable[i].pl_pid) {
752
753 move_amt = pidcnt - i;
754 /*
755 * Move table down
756 */
757 if (move_amt != 0) {
758 (void) memmove(&pidtable[i+1], &pidtable[i],
759 move_amt * sizeof (struct pidentry));
760 (void) memmove(&fdtable[i+1], &fdtable[i],
761 move_amt * sizeof (pollfd_t));
762 }
763 }
764 }
765
766 /*
767 * Fill in the events field for poll and copy the entry into the array
768 */
769 fdtable[i].events = 0;
770 fdtable[i].revents = 0;
771 fdtable[i].fd = fd;
772
773 /*
774 * Likewise, setup pid field and pointer (index) to the fdtable entry
775 */
776 pidtable[i].pl_pid = pid;
777
778 pidcnt++; /* Bump the pid count */
779 dprintf((" add_pid: pid = %d fd = %d index = %d pidcnt = %d\n",
780 (int)pid, fd, i, pidcnt));
781 }
782
783
784 /*
785 * rem_pid - Remove an entry from the table and check to see if its
786 * not in the utmpx file.
787 * If i != -1 don't look up the pid, use i as index
788 *
789 * pid - Pid of process to clean or 0 if we don't know it
790 *
791 * i - Index into table or -1 if we need to look it up
792 *
793 * clean_it - Clean the entry, or just remove from table?
794 */
795
796 static void
rem_pid(pid_t pid,int i,int clean_it)797 rem_pid(pid_t pid, int i, int clean_it)
798 {
799 int move_amt;
800
801 dprintf((" rem_pid: pid = %d i = %d", (int)pid, i));
802
803 /*
804 * Don't allow slot 0 in the table to be removed - utmppipe fd
805 */
806 if ((i == -1 && pid == 0) || (i == 0)) {
807 dprintf((" - attempted to remove proc 0\n"));
808 return;
809 }
810
811 if (i != -1 || find_pid(pid, &i) == 1) { /* Found the entry */
812 (void) close(fdtable[i].fd); /* We're done with the fd */
813
814 dprintf((" fd = %d\n", fdtable[i].fd));
815
816 if (clean_it == CLEANIT)
817 clean_entry(i);
818
819 move_amt = (pidcnt - i) - 1;
820 /*
821 * Remove entries from the tables.
822 */
823 (void) memmove(&pidtable[i], &pidtable[i+1],
824 move_amt * sizeof (struct pidentry));
825
826 (void) memmove(&fdtable[i], &fdtable[i+1],
827 move_amt * sizeof (pollfd_t));
828
829 /*
830 * decrement the pid count - one less pid to worry about
831 */
832 pidcnt--;
833 }
834 if (i == -1)
835 dprintf((" - entry not found \n"));
836 }
837
838
839 /*
840 * find_pid - Returns an index into the pidtable of the specifed pid,
841 * else -1 if not found
842 */
843
844 static int
find_pid(pid_t pid,int * i)845 find_pid(pid_t pid, int *i)
846 {
847 struct pidentry pe;
848 struct pidentry *p;
849
850 pe.pl_pid = pid;
851 p = bsearch(&pe, pidtable, pidcnt, sizeof (struct pidentry), pidcmp);
852
853 if (p == NULL)
854 return (0);
855 else {
856 *i = p - (struct pidentry *)pidtable;
857 return (1);
858 }
859 }
860
861
862 /*
863 * Pidcmp - Used by besearch for sorting and finding process IDs.
864 */
865
866 static int
pidcmp(struct pidentry * a,struct pidentry * b)867 pidcmp(struct pidentry *a, struct pidentry *b)
868 {
869 if (b == NULL || a == NULL)
870 return (0);
871 return (a->pl_pid - b->pl_pid);
872 }
873
874
875 /*
876 * proc_to_fd - Take a process ID and return an open file descriptor to the
877 * /proc file for the specified process.
878 */
879 static int
proc_to_fd(pid_t pid)880 proc_to_fd(pid_t pid)
881 {
882 char procname[64];
883 int fd, dfd;
884
885 (void) sprintf(procname, "/proc/%d/psinfo", (int)pid);
886
887 if ((fd = open(procname, O_RDONLY)) >= 0) {
888 /*
889 * dup the fd above the low order values to assure
890 * stdio works for other fds - paranoia.
891 */
892 if (fd < EXTRA_MARGIN) {
893 dfd = fcntl(fd, F_DUPFD, EXTRA_MARGIN);
894 if (dfd > 0) {
895 (void) close(fd);
896 fd = dfd;
897 }
898 }
899 /*
900 * More paranoia - set the close on exec flag
901 */
902 (void) fcntl(fd, F_SETFD, 1);
903 return (fd);
904 }
905 if (errno == ENOENT)
906 return (-1);
907
908 if (errno == EMFILE) {
909 /*
910 * This is fatal, since libc won't be able to allocate
911 * any fds for the pututxline() routines
912 */
913 fatal("Out of file descriptors");
914 }
915 fatal(procname); /* Only get here on error */
916 return (-1);
917 }
918
919
920 /*
921 * *** Utmpx Cleaning Utilities ***
922 */
923
924 /*
925 * Clean_entry - Cleans the specified entry - where i is an index
926 * into the pid_table.
927 */
928 static void
clean_entry(int i)929 clean_entry(int i)
930 {
931 struct utmpx *u;
932
933 if (pidcnt == 0)
934 return;
935
936 dprintf((" Cleaning %d\n", (int)pidtable[i].pl_pid));
937
938 /*
939 * Double check if the process is dead.
940 */
941 if (proc_is_alive(pidtable[i].pl_pid)) {
942 dprintf((" Bad attempt to clean %d\n",
943 (int)pidtable[i].pl_pid));
944 return;
945 }
946
947 /*
948 * Find the entry that corresponds to this pid.
949 * Do nothing if entry not found in utmpx file.
950 */
951 setutxent();
952 while ((u = getutxent()) != NULL) {
953 if (u->ut_pid == pidtable[i].pl_pid) {
954 if (u->ut_type == USER_PROCESS) {
955 clean_utmpx_ent(u);
956 }
957 }
958 }
959 endutxent();
960 }
961
962
963 /*
964 * clean_utmpx_ent - Clean a utmpx entry
965 */
966
967 static void
clean_utmpx_ent(struct utmpx * u)968 clean_utmpx_ent(struct utmpx *u)
969 {
970 dprintf((" clean_utmpx_ent: %d\n", (int)u->ut_pid));
971 u->ut_type = DEAD_PROCESS;
972 (void) time(&u->ut_xtime);
973 (void) pututxline(u);
974 updwtmpx(WTMPX_FILE, u);
975 /*
976 * XXX update wtmp for ! nonuserx entries?
977 */
978 }
979
980 /*
981 * *** Error Handling and Debugging Routines ***
982 */
983
984 /*
985 * fatal - Catastrophic failure
986 */
987
988 static void
fatal(char * str)989 fatal(char *str)
990 {
991 int oerrno = errno;
992
993 syslog(LOG_ALERT, "%s", str);
994 if (Debug == 1) {
995 if ((errno = oerrno) != 0)
996 perror(prog_name);
997 dprintf(("%s\n", str));
998 }
999 exit(1);
1000 }
1001
1002 /*
1003 * nonfatal - Non-Catastrophic failure - print message and errno
1004 */
1005
1006 static void
nonfatal(char * str)1007 nonfatal(char *str)
1008 {
1009 syslog(LOG_WARNING, "%s", str);
1010
1011 if (Debug == 1) {
1012 if (errno != 0)
1013 perror(prog_name);
1014 dprintf(("%c%s\n", 7, str));
1015 print_tables();
1016 (void) sleep(5); /* Time to read debug messages */
1017 }
1018 }
1019
1020 /*
1021 * print_tables - Print internal tables - for debugging
1022 */
1023
1024 static void
print_tables()1025 print_tables()
1026 {
1027 int i;
1028
1029 if (Debug == 0)
1030 return;
1031
1032 dprintf(("pidtable: "));
1033 for (i = 0; i < pidcnt; i++)
1034 dprintf(("%d: %d ", i, (int)pidtable[i].pl_pid));
1035 dprintf(("\n"));
1036 dprintf(("fdtable: "));
1037 for (i = 0; i < pidcnt; i++)
1038 dprintf(("%d: %d ", i, fdtable[i].fd));
1039 dprintf(("\n"));
1040 }
1041
1042 /*
1043 * proc_is_alive - Check to see if a process is alive AND its
1044 * not a zombie. Returns 1 if process is alive
1045 * and zero if it is dead or a zombie.
1046 */
1047
1048 static int
proc_is_alive(pid_t pid)1049 proc_is_alive(pid_t pid)
1050 {
1051 char psinfoname[64];
1052 int fd;
1053 psinfo_t psinfo;
1054
1055 if (kill(pid, 0) != 0)
1056 return (0); /* Kill failed - no process */
1057
1058 /*
1059 * The process exists, so check if it's a zombie.
1060 */
1061 (void) sprintf(psinfoname, "/proc/%d/psinfo", (int)pid);
1062
1063 if ((fd = open(psinfoname, O_RDONLY)) < 0 ||
1064 read(fd, &psinfo, sizeof (psinfo)) != sizeof (psinfo)) {
1065 /*
1066 * We either couldn't open the proc, or we did but the
1067 * read of the psinfo file failed, so pid is nonexistent.
1068 */
1069 psinfo.pr_nlwp = 0;
1070 }
1071 if (fd >= 0)
1072 (void) close(fd);
1073
1074 /* if pr_nlwp == 0, process is a zombie */
1075 return (psinfo.pr_nlwp != 0);
1076 }
1077
1078 /*
1079 * warn_utmp - /var/adm/utmp has been deprecated. It should no longer
1080 * be used. Applications that try to directly manipulate
1081 * it may cause problems. Since the file is no longer
1082 * shipped, if it appears on a system it's because an
1083 * old application created it. We'll have utmpd
1084 * complain about it periodically.
1085 */
1086
1087 static void
warn_utmp()1088 warn_utmp()
1089 {
1090 struct stat s;
1091
1092 if (lstat(UTMP_FILE, &s) == 0 &&
1093 s.st_size % sizeof (struct utmp) == 0) {
1094 nonfatal("WARNING: /var/adm/utmp exists!\nSee "
1095 "utmp(4) for more information");
1096 }
1097 }
1098
1099 /*
1100 * validate_default - validate and assign defaults.
1101 */
1102
1103 static int
validate_default(char * defp,int * flag)1104 validate_default(char *defp, int *flag)
1105 {
1106 long lval;
1107 char *endptr;
1108
1109 errno = 0;
1110 lval = strtol(defp, &endptr, 10);
1111
1112 if (errno != 0 || lval > INT_MAX || lval <= 0)
1113 return (-1);
1114
1115 while (isspace(*endptr) != 0)
1116 endptr++;
1117
1118 if (*endptr != '\0')
1119 return (-1);
1120
1121 *flag = lval;
1122 return (0);
1123 }
1124