xref: /freebsd/usr.sbin/ppp/timer.c (revision fd45b686f9d92f583366c75b22c04c7ee49709c0)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 
31 #include <errno.h>
32 #include <signal.h>
33 #include <stdarg.h>
34 #include <stdio.h>
35 #include <string.h>
36 #include <sys/time.h>
37 #include <termios.h>
38 
39 #include "log.h"
40 #include "sig.h"
41 #include "timer.h"
42 #include "descriptor.h"
43 #include "prompt.h"
44 
45 
46 #define RESTVAL(t) \
47     ((t).it_value.tv_sec * SECTICKS + (t).it_value.tv_usec / TICKUNIT + \
48      ((((t).it_value.tv_usec % TICKUNIT) >= (TICKUNIT >> 1)) ? 1 : 0))
49 
50 static struct pppTimer *TimerList = NULL, *ExpiredList = NULL;
51 
52 static void StopTimerNoBlock(struct pppTimer *);
53 
54 static const char *
55 tState2Nam(u_int state)
56 {
57   static const char * const StateNames[] = { "stopped", "running", "expired" };
58 
59   if (state >= sizeof StateNames / sizeof StateNames[0])
60     return "unknown";
61   return StateNames[state];
62 }
63 
64 void
65 timer_Stop(struct pppTimer *tp)
66 {
67   sigset_t mask, omask;
68 
69   sigemptyset(&mask);
70   sigaddset(&mask, SIGALRM);
71   sigprocmask(SIG_BLOCK, &mask, &omask);
72   StopTimerNoBlock(tp);
73   sigprocmask(SIG_SETMASK, &omask, NULL);
74 }
75 
76 void
77 timer_Start(struct pppTimer *tp)
78 {
79   struct itimerval itimer;
80   struct pppTimer *t, *pt;
81   u_long ticks = 0;
82   sigset_t mask, omask;
83 
84   sigemptyset(&mask);
85   sigaddset(&mask, SIGALRM);
86   sigprocmask(SIG_BLOCK, &mask, &omask);
87 
88   if (tp->state != TIMER_STOPPED)
89     StopTimerNoBlock(tp);
90 
91   if (tp->load == 0) {
92     log_Printf(LogTIMER, "%s timer[%p] has 0 load!\n", tp->name, tp);
93     sigprocmask(SIG_SETMASK, &omask, NULL);
94     return;
95   }
96 
97   /*
98    * We just need to insert tp in the correct relative place.  We don't
99    * need to adjust TimerList->rest (yet).
100    */
101   if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
102     ticks = RESTVAL(itimer) - TimerList->rest;
103 
104   pt = NULL;
105   for (t = TimerList; t; t = t->next) {
106     if (ticks + t->rest >= tp->load)
107       break;
108     ticks += t->rest;
109     pt = t;
110   }
111 
112   tp->state = TIMER_RUNNING;
113   tp->rest = tp->load - ticks;
114 
115   if (t)
116     log_Printf(LogTIMER, "timer_Start: Inserting %s timer[%p] before %s "
117               "timer[%p], delta = %ld\n", tp->name, tp, t->name, t, tp->rest);
118   else
119     log_Printf(LogTIMER, "timer_Start: Inserting %s timer[%p]\n", tp->name, tp);
120 
121   /* Insert given *tp just before *t */
122   tp->next = t;
123   if (pt) {
124     pt->next = tp;
125   } else {
126     TimerList = tp;
127     timer_InitService(t != NULL);	/* [re]Start the Timer Service */
128   }
129   if (t)
130     t->rest -= tp->rest;
131 
132   sigprocmask(SIG_SETMASK, &omask, NULL);
133 }
134 
135 static void
136 StopTimerNoBlock(struct pppTimer *tp)
137 {
138   struct itimerval itimer;
139   struct pppTimer *t, *pt;
140 
141   /*
142    * A RUNNING timer must be removed from TimerList (->next list).
143    * A STOPPED timer isn't in any list, but may have a bogus [e]next field.
144    * An EXPIRED timer is in the ->enext list.
145    */
146 
147   if (tp->state == TIMER_STOPPED)
148     return;
149 
150   pt = NULL;
151   for (t = TimerList; t != tp && t != NULL; t = t->next)
152     pt = t;
153 
154   if (t) {
155     if (pt)
156       pt->next = t->next;
157     else {
158       TimerList = t->next;
159       if (TimerList == NULL)	/* Last one ? */
160 	timer_TermService();	/* Terminate Timer Service */
161     }
162     if (t->next) {
163       if (!pt && getitimer(ITIMER_REAL, &itimer) == 0)
164         t->next->rest += RESTVAL(itimer); /* t (tp) was the first in the list */
165       else
166         t->next->rest += t->rest;
167       if (!pt && t->next->rest > 0)   /* t->next is now the first in the list */
168         timer_InitService(1);
169     }
170   } else {
171     /* Search for any pending expired timers */
172     pt = NULL;
173     for (t = ExpiredList; t != tp && t != NULL; t = t->enext)
174       pt = t;
175 
176     if (t) {
177       if (pt)
178         pt->enext = t->enext;
179       else
180         ExpiredList = t->enext;
181     } else if (tp->state == TIMER_RUNNING)
182       log_Printf(LogERROR, "Oops, %s timer not found!!\n", tp->name);
183   }
184 
185   tp->next = tp->enext = NULL;
186   tp->state = TIMER_STOPPED;
187 }
188 
189 static void
190 TimerService(void)
191 {
192   struct pppTimer *tp, *exp, *next;
193 
194   if (log_IsKept(LogTIMER)) {
195     static time_t t;		/* Only show timers globally every second */
196     time_t n = time(NULL);
197 
198     if (n > t)
199       timer_Show(LogTIMER, NULL);
200     t = n;
201   }
202 
203   tp = TimerList;
204   if (tp) {
205     tp->rest = 0;
206 
207     /* Multiple timers might expire at once. Create a list of expired timers */
208     exp = NULL;
209     do {
210       tp->state = TIMER_EXPIRED;
211       next = tp->next;
212       tp->enext = exp;
213       exp = tp;
214       tp = next;
215     } while (tp && tp->rest == 0);
216 
217     TimerList = tp;
218     if (TimerList != NULL)	/* Any timers remaining ? */
219       timer_InitService(1);	/* Restart the Timer Service */
220     else
221       timer_TermService();	/* Stop the Timer Service */
222 
223     /* Process all expired timers */
224     while (exp) {
225       ExpiredList = exp->enext;
226       exp->enext = NULL;
227       if (exp->func)
228         (*exp->func)(exp->arg);
229       exp = ExpiredList;
230     }
231   }
232 }
233 
234 void
235 timer_Show(int LogLevel, struct prompt *prompt)
236 {
237   struct itimerval itimer;
238   struct pppTimer *pt;
239   long rest;
240 
241   /*
242    * Adjust the base time so that the deltas reflect what's really
243    * happening.  Changing TimerList->rest might cause it to become zero
244    * (if getitimer() returns a value close to zero), and the
245    * timer_InitService() call will call setitimer() with zero it_value,
246    * stopping the itimer... so be careful!
247    */
248   if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
249     rest = RESTVAL(itimer) - TimerList->rest;
250   else
251     rest = 0;
252 
253 #define SECS(val)	((val) / SECTICKS)
254 #define HSECS(val)	(((val) % SECTICKS) * 100 / SECTICKS)
255 #define DISP								\
256   "%s timer[%p]: freq = %ld.%02lds, next = %lu.%02lus, state = %s\n",	\
257   pt->name, pt, SECS(pt->load), HSECS(pt->load), SECS(rest),		\
258   HSECS(rest), tState2Nam(pt->state)
259 
260   if (!prompt)
261     log_Printf(LogLevel, "---- Begin of Timer Service List---\n");
262 
263   for (pt = TimerList; pt; pt = pt->next) {
264     rest += pt->rest;
265     if (prompt)
266       prompt_Printf(prompt, DISP);
267     else
268       log_Printf(LogLevel, DISP);
269   }
270 
271   if (!prompt)
272     log_Printf(LogLevel, "---- End of Timer Service List ---\n");
273 }
274 
275 void
276 timer_InitService(int restart)
277 {
278   struct itimerval itimer;
279 
280   if (TimerList) {
281     if (!restart)
282       sig_signal(SIGALRM, (void (*)(int))TimerService);
283     itimer.it_interval.tv_sec = 0;
284     itimer.it_interval.tv_usec = 0;
285     itimer.it_value.tv_sec = TimerList->rest / SECTICKS;
286     itimer.it_value.tv_usec = (TimerList->rest % SECTICKS) * TICKUNIT;
287     if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
288       log_Printf(LogERROR, "Unable to set itimer (%s)\n", strerror(errno));
289   }
290 }
291 
292 void
293 timer_TermService(void)
294 {
295   struct itimerval itimer;
296 
297   itimer.it_interval.tv_usec = itimer.it_interval.tv_sec = 0;
298   itimer.it_value.tv_usec = itimer.it_value.tv_sec = 0;
299   if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
300     log_Printf(LogERROR, "Unable to set itimer (%s)\n", strerror(errno));
301   sig_signal(SIGALRM, SIG_IGN);
302 }
303