xref: /freebsd/usr.sbin/ppp/timer.c (revision 3c4ba5f55438f7afd4f4b0b56f88f2bb505fd6a6)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1996 - 2001, 2009 Brian Somers <brian@Awfulhak.org>
5  *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
6  *                           Internet Initiative Japan, Inc (IIJ)
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  *
30  * $FreeBSD$
31  */
32 
33 #include <errno.h>
34 #include <signal.h>
35 #include <stdarg.h>
36 #include <stdio.h>
37 #include <string.h>
38 #include <sys/time.h>
39 #include <termios.h>
40 
41 #include "log.h"
42 #include "sig.h"
43 #include "timer.h"
44 #include "descriptor.h"
45 #include "prompt.h"
46 
47 
48 #define RESTVAL(t) \
49     ((t).it_value.tv_sec * SECTICKS + (t).it_value.tv_usec / TICKUNIT + \
50      ((((t).it_value.tv_usec % TICKUNIT) >= (TICKUNIT >> 1)) ? 1 : 0))
51 
52 static struct pppTimer *TimerList = NULL, *ExpiredList = NULL;
53 
54 static void StopTimerNoBlock(struct pppTimer *);
55 
56 static const char *
57 tState2Nam(u_int state)
58 {
59   static const char * const StateNames[] = { "stopped", "running", "expired" };
60 
61   if (state >= sizeof StateNames / sizeof StateNames[0])
62     return "unknown";
63   return StateNames[state];
64 }
65 
66 void
67 timer_Stop(struct pppTimer *tp)
68 {
69   sigset_t mask, omask;
70 
71   sigemptyset(&mask);
72   sigaddset(&mask, SIGALRM);
73   sigprocmask(SIG_BLOCK, &mask, &omask);
74   StopTimerNoBlock(tp);
75   sigprocmask(SIG_SETMASK, &omask, NULL);
76 }
77 
78 void
79 timer_Start(struct pppTimer *tp)
80 {
81   struct itimerval itimer;
82   struct pppTimer *t, *pt;
83   u_long ticks = 0;
84   sigset_t mask, omask;
85 
86   sigemptyset(&mask);
87   sigaddset(&mask, SIGALRM);
88   sigprocmask(SIG_BLOCK, &mask, &omask);
89 
90   if (tp->state != TIMER_STOPPED)
91     StopTimerNoBlock(tp);
92 
93   if (tp->load == 0) {
94     log_Printf(LogTIMER, "%s timer[%p] has 0 load!\n", tp->name, tp);
95     sigprocmask(SIG_SETMASK, &omask, NULL);
96     return;
97   }
98 
99   /*
100    * We just need to insert tp in the correct relative place.  We don't
101    * need to adjust TimerList->rest (yet).
102    */
103   if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
104     ticks = RESTVAL(itimer) - TimerList->rest;
105 
106   pt = NULL;
107   for (t = TimerList; t; t = t->next) {
108     if (ticks + t->rest >= tp->load)
109       break;
110     ticks += t->rest;
111     pt = t;
112   }
113 
114   tp->state = TIMER_RUNNING;
115   tp->rest = tp->load - ticks;
116 
117   if (t)
118     log_Printf(LogTIMER, "timer_Start: Inserting %s timer[%p] before %s "
119               "timer[%p], delta = %ld\n", tp->name, tp, t->name, t, tp->rest);
120   else
121     log_Printf(LogTIMER, "timer_Start: Inserting %s timer[%p]\n", tp->name, tp);
122 
123   /* Insert given *tp just before *t */
124   tp->next = t;
125   if (pt) {
126     pt->next = tp;
127   } else {
128     TimerList = tp;
129     timer_InitService(t != NULL);	/* [re]Start the Timer Service */
130   }
131   if (t)
132     t->rest -= tp->rest;
133 
134   sigprocmask(SIG_SETMASK, &omask, NULL);
135 }
136 
137 static void
138 StopTimerNoBlock(struct pppTimer *tp)
139 {
140   struct itimerval itimer;
141   struct pppTimer *t, *pt;
142 
143   /*
144    * A RUNNING timer must be removed from TimerList (->next list).
145    * A STOPPED timer isn't in any list, but may have a bogus [e]next field.
146    * An EXPIRED timer is in the ->enext list.
147    */
148 
149   if (tp->state == TIMER_STOPPED)
150     return;
151 
152   pt = NULL;
153   for (t = TimerList; t != tp && t != NULL; t = t->next)
154     pt = t;
155 
156   if (t) {
157     if (pt)
158       pt->next = t->next;
159     else {
160       TimerList = t->next;
161       if (TimerList == NULL)	/* Last one ? */
162 	timer_TermService();	/* Terminate Timer Service */
163     }
164     if (t->next) {
165       if (!pt && getitimer(ITIMER_REAL, &itimer) == 0)
166         t->next->rest += RESTVAL(itimer); /* t (tp) was the first in the list */
167       else
168         t->next->rest += t->rest;
169       if (!pt && t->next->rest > 0)   /* t->next is now the first in the list */
170         timer_InitService(1);
171     }
172   } else {
173     /* Search for any pending expired timers */
174     pt = NULL;
175     for (t = ExpiredList; t != tp && t != NULL; t = t->enext)
176       pt = t;
177 
178     if (t) {
179       if (pt)
180         pt->enext = t->enext;
181       else
182         ExpiredList = t->enext;
183     } else if (tp->state == TIMER_RUNNING)
184       log_Printf(LogERROR, "Oops, %s timer not found!!\n", tp->name);
185   }
186 
187   tp->next = tp->enext = NULL;
188   tp->state = TIMER_STOPPED;
189 }
190 
191 static void
192 TimerService(void)
193 {
194   struct pppTimer *tp, *exp, *next;
195 
196   if (log_IsKept(LogTIMER)) {
197     static time_t t;		/* Only show timers globally every second */
198     time_t n = time(NULL);
199 
200     if (n > t)
201       timer_Show(LogTIMER, NULL);
202     t = n;
203   }
204 
205   tp = TimerList;
206   if (tp) {
207     tp->rest = 0;
208 
209     /* Multiple timers might expire at once. Create a list of expired timers */
210     exp = NULL;
211     do {
212       tp->state = TIMER_EXPIRED;
213       next = tp->next;
214       tp->enext = exp;
215       exp = tp;
216       tp = next;
217     } while (tp && tp->rest == 0);
218 
219     TimerList = tp;
220     if (TimerList != NULL)	/* Any timers remaining ? */
221       timer_InitService(1);	/* Restart the Timer Service */
222     else
223       timer_TermService();	/* Stop the Timer Service */
224 
225     /* Process all expired timers */
226     while (exp) {
227       ExpiredList = exp->enext;
228       exp->enext = NULL;
229       if (exp->func)
230         (*exp->func)(exp->arg);
231       exp = ExpiredList;
232     }
233   }
234 }
235 
236 void
237 timer_Show(int LogLevel, struct prompt *prompt)
238 {
239   struct itimerval itimer;
240   struct pppTimer *pt;
241   long rest;
242 
243   /*
244    * Adjust the base time so that the deltas reflect what's really
245    * happening.  Changing TimerList->rest might cause it to become zero
246    * (if getitimer() returns a value close to zero), and the
247    * timer_InitService() call will call setitimer() with zero it_value,
248    * stopping the itimer... so be careful!
249    */
250   if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
251     rest = RESTVAL(itimer) - TimerList->rest;
252   else
253     rest = 0;
254 
255 #define SECS(val)	((val) / SECTICKS)
256 #define HSECS(val)	(((val) % SECTICKS) * 100 / SECTICKS)
257 #define DISP								\
258   "%s timer[%p]: freq = %ld.%02lds, next = %lu.%02lus, state = %s\n",	\
259   pt->name, pt, SECS(pt->load), HSECS(pt->load), SECS(rest),		\
260   HSECS(rest), tState2Nam(pt->state)
261 
262   if (!prompt)
263     log_Printf(LogLevel, "---- Begin of Timer Service List---\n");
264 
265   for (pt = TimerList; pt; pt = pt->next) {
266     rest += pt->rest;
267     if (prompt)
268       prompt_Printf(prompt, DISP);
269     else
270       log_Printf(LogLevel, DISP);
271   }
272 
273   if (!prompt)
274     log_Printf(LogLevel, "---- End of Timer Service List ---\n");
275 }
276 
277 void
278 timer_InitService(int restart)
279 {
280   struct itimerval itimer;
281 
282   if (TimerList) {
283     if (!restart)
284       sig_signal(SIGALRM, (void (*)(int))TimerService);
285     itimer.it_interval.tv_sec = 0;
286     itimer.it_interval.tv_usec = 0;
287     itimer.it_value.tv_sec = TimerList->rest / SECTICKS;
288     itimer.it_value.tv_usec = (TimerList->rest % SECTICKS) * TICKUNIT;
289     if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
290       log_Printf(LogERROR, "Unable to set itimer (%s)\n", strerror(errno));
291   }
292 }
293 
294 void
295 timer_TermService(void)
296 {
297   struct itimerval itimer;
298 
299   itimer.it_interval.tv_usec = itimer.it_interval.tv_sec = 0;
300   itimer.it_value.tv_usec = itimer.it_value.tv_sec = 0;
301   if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
302     log_Printf(LogERROR, "Unable to set itimer (%s)\n", strerror(errno));
303   sig_signal(SIGALRM, SIG_IGN);
304 }
305