xref: /freebsd/usr.sbin/ppp/timer.c (revision 74bf4e164ba5851606a27d4feff27717452583e5)
1 /*-
2  * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
3  *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
4  *                           Internet Initiative Japan, Inc (IIJ)
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
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   /* Adjust our first delta so that it reflects what's really happening */
98   if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
99     TimerList->rest = RESTVAL(itimer);
100 
101   pt = NULL;
102   for (t = TimerList; t; t = t->next) {
103     if (ticks + t->rest >= tp->load)
104       break;
105     ticks += t->rest;
106     pt = t;
107   }
108 
109   tp->state = TIMER_RUNNING;
110   tp->rest = tp->load - ticks;
111 
112   if (t)
113     log_Printf(LogTIMER, "timer_Start: Inserting %s timer[%p] before %s "
114               "timer[%p], delta = %ld\n", tp->name, tp, t->name, t, tp->rest);
115   else
116     log_Printf(LogTIMER, "timer_Start: Inserting %s timer[%p]\n", tp->name, tp);
117 
118   /* Insert given *tp just before *t */
119   tp->next = t;
120   if (pt) {
121     pt->next = tp;
122   } else {
123     TimerList = tp;
124     timer_InitService(t != NULL);	/* [re]Start the Timer Service */
125   }
126   if (t)
127     t->rest -= tp->rest;
128 
129   sigprocmask(SIG_SETMASK, &omask, NULL);
130 }
131 
132 static void
133 StopTimerNoBlock(struct pppTimer *tp)
134 {
135   struct pppTimer *t, *pt;
136 
137   /*
138    * A RUNNING timer must be removed from TimerList (->next list).
139    * A STOPPED timer isn't in any list, but may have a bogus [e]next field.
140    * An EXPIRED timer is in the ->enext list.
141    */
142 
143   if (tp->state == TIMER_STOPPED)
144     return;
145 
146   pt = NULL;
147   for (t = TimerList; t != tp && t != NULL; t = t->next)
148     pt = t;
149 
150   if (t) {
151     if (pt)
152       pt->next = t->next;
153     else {
154       TimerList = t->next;
155       if (TimerList == NULL)	/* Last one ? */
156 	timer_TermService();	/* Terminate Timer Service */
157     }
158     if (t->next) {
159       if (!pt) {		/* t (tp) was the first in the list */
160         struct itimerval itimer;
161 
162         if (getitimer(ITIMER_REAL, &itimer) == 0)
163           t->rest = RESTVAL(itimer);
164       }
165       t->next->rest += t->rest;
166       if (!pt)			/* t->next is now the first in the list */
167         timer_InitService(1);
168     }
169   } else {
170     /* Search for any pending expired timers */
171     pt = NULL;
172     for (t = ExpiredList; t != tp && t != NULL; t = t->enext)
173       pt = t;
174 
175     if (t) {
176       if (pt)
177         pt->enext = t->enext;
178       else
179         ExpiredList = t->enext;
180     } else if (tp->state == TIMER_RUNNING)
181       log_Printf(LogERROR, "Oops, %s timer not found!!\n", tp->name);
182   }
183 
184   tp->next = tp->enext = NULL;
185   tp->state = TIMER_STOPPED;
186 }
187 
188 static void
189 TimerService(void)
190 {
191   struct pppTimer *tp, *exp, *next;
192 
193   if (log_IsKept(LogTIMER)) {
194     static time_t t;		/* Only show timers globally every second */
195     time_t n = time(NULL);
196 
197     if (n > t)
198       timer_Show(LogTIMER, NULL);
199     t = n;
200   }
201 
202   tp = TimerList;
203   if (tp) {
204     tp->rest = 0;
205 
206     /* Multiple timers might expire at once. Create a list of expired timers */
207     exp = NULL;
208     do {
209       tp->state = TIMER_EXPIRED;
210       next = tp->next;
211       tp->enext = exp;
212       exp = tp;
213       tp = next;
214     } while (tp && tp->rest == 0);
215 
216     TimerList = tp;
217     if (TimerList != NULL)	/* Any timers remaining ? */
218       timer_InitService(1);	/* Restart the Timer Service */
219     else
220       timer_TermService();	/* Stop the Timer Service */
221 
222     /* Process all expired timers */
223     while (exp) {
224       ExpiredList = exp->enext;
225       exp->enext = NULL;
226       if (exp->func)
227         (*exp->func)(exp->arg);
228       exp = ExpiredList;
229     }
230   }
231 }
232 
233 void
234 timer_Show(int LogLevel, struct prompt *prompt)
235 {
236   struct itimerval itimer;
237   struct pppTimer *pt;
238   u_long rest = 0;
239 
240   /* Adjust our first delta so that it reflects what's really happening */
241   if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
242     TimerList->rest = RESTVAL(itimer);
243 
244 #define SECS(val)	((val) / SECTICKS)
245 #define HSECS(val)	(((val) % SECTICKS) * 100 / SECTICKS)
246 #define DISP								\
247   "%s timer[%p]: freq = %ld.%02lds, next = %lu.%02lus, state = %s\n",	\
248   pt->name, pt, SECS(pt->load), HSECS(pt->load), SECS(rest),		\
249   HSECS(rest), tState2Nam(pt->state)
250 
251   if (!prompt)
252     log_Printf(LogLevel, "---- Begin of Timer Service List---\n");
253 
254   for (pt = TimerList; pt; pt = pt->next) {
255     rest += pt->rest;
256     if (prompt)
257       prompt_Printf(prompt, DISP);
258     else
259       log_Printf(LogLevel, DISP);
260   }
261 
262   if (!prompt)
263     log_Printf(LogLevel, "---- End of Timer Service List ---\n");
264 }
265 
266 void
267 timer_InitService(int restart)
268 {
269   struct itimerval itimer;
270 
271   if (TimerList) {
272     if (!restart)
273       sig_signal(SIGALRM, (void (*)(int))TimerService);
274     itimer.it_interval.tv_sec = 0;
275     itimer.it_interval.tv_usec = 0;
276     itimer.it_value.tv_sec = TimerList->rest / SECTICKS;
277     itimer.it_value.tv_usec = (TimerList->rest % SECTICKS) * TICKUNIT;
278     if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
279       log_Printf(LogERROR, "Unable to set itimer (%s)\n", strerror(errno));
280   }
281 }
282 
283 void
284 timer_TermService(void)
285 {
286   struct itimerval itimer;
287 
288   itimer.it_interval.tv_usec = itimer.it_interval.tv_sec = 0;
289   itimer.it_value.tv_usec = itimer.it_value.tv_sec = 0;
290   if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
291     log_Printf(LogERROR, "Unable to set itimer (%s)\n", strerror(errno));
292   sig_signal(SIGALRM, SIG_IGN);
293 }
294