timer.c revision 58030 
1/*
2 *		PPP Timer Processing Module
3 *
4 *	    Written by Toshiharu OHNO (tony-o@iij.ad.jp)
5 *
6 *   Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that the above copyright notice and this paragraph are
10 * duplicated in all such forms and that any documentation,
11 * advertising materials, and other materials related to such
12 * distribution and use acknowledge that the software was developed
13 * by the Internet Initiative Japan, Inc.  The name of the
14 * IIJ may not be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 *
20 * $FreeBSD: head/usr.sbin/ppp/timer.c 58030 2000-03-14 01:46:34Z brian $
21 *
22 *  TODO:
23 */
24
25#include <errno.h>
26#include <signal.h>
27#include <stdio.h>
28#include <string.h>
29#include <sys/time.h>
30#include <termios.h>
31
32#include "log.h"
33#include "sig.h"
34#include "timer.h"
35#include "descriptor.h"
36#include "prompt.h"
37
38
39#define RESTVAL(t) \
40    ((t).it_value.tv_sec * SECTICKS + (t).it_value.tv_usec / TICKUNIT + \
41     ((((t).it_value.tv_usec % TICKUNIT) >= (TICKUNIT >> 1)) ? 1 : 0))
42
43static struct pppTimer *TimerList = NULL, *ExpiredList = NULL;
44
45static void StopTimerNoBlock(struct pppTimer *);
46
47static const char *
48tState2Nam(u_int state)
49{
50  static const char * const StateNames[] = { "stopped", "running", "expired" };
51
52  if (state >= sizeof StateNames / sizeof StateNames[0])
53    return "unknown";
54  return StateNames[state];
55}
56
57void
58timer_Stop(struct pppTimer *tp)
59{
60  int omask;
61
62  omask = sigblock(sigmask(SIGALRM));
63  StopTimerNoBlock(tp);
64  sigsetmask(omask);
65}
66
67void
68timer_Start(struct pppTimer *tp)
69{
70  struct itimerval itimer;
71  struct pppTimer *t, *pt;
72  u_long ticks = 0;
73  int omask;
74
75  omask = sigblock(sigmask(SIGALRM));
76
77  if (tp->state != TIMER_STOPPED)
78    StopTimerNoBlock(tp);
79
80  if (tp->load == 0) {
81    log_Printf(LogTIMER, "%s timer[%p] has 0 load!\n", tp->name, tp);
82    sigsetmask(omask);
83    return;
84  }
85
86  /* Adjust our first delta so that it reflects what's really happening */
87  if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
88    TimerList->rest = RESTVAL(itimer);
89
90  pt = NULL;
91  for (t = TimerList; t; t = t->next) {
92    if (ticks + t->rest >= tp->load)
93      break;
94    ticks += t->rest;
95    pt = t;
96  }
97
98  tp->state = TIMER_RUNNING;
99  tp->rest = tp->load - ticks;
100
101  if (t)
102    log_Printf(LogTIMER, "timer_Start: Inserting %s timer[%p] before %s "
103              "timer[%p], delta = %ld\n", tp->name, tp, t->name, t, tp->rest);
104  else
105    log_Printf(LogTIMER, "timer_Start: Inserting %s timer[%p]\n", tp->name, tp);
106
107  /* Insert given *tp just before *t */
108  tp->next = t;
109  if (pt) {
110    pt->next = tp;
111  } else {
112    TimerList = tp;
113    timer_InitService(t != NULL);	/* [re]Start the Timer Service */
114  }
115  if (t)
116    t->rest -= tp->rest;
117
118  sigsetmask(omask);
119}
120
121static void
122StopTimerNoBlock(struct pppTimer *tp)
123{
124  struct pppTimer *t, *pt;
125
126  /*
127   * A RUNNING timer must be removed from TimerList (->next list).
128   * A STOPPED timer isn't in any list, but may have a bogus [e]next field.
129   * An EXPIRED timer is in the ->enext list.
130   */
131
132  if (tp->state == TIMER_STOPPED)
133    return;
134
135  pt = NULL;
136  for (t = TimerList; t != tp && t != NULL; t = t->next)
137    pt = t;
138
139  if (t) {
140    if (pt)
141      pt->next = t->next;
142    else {
143      TimerList = t->next;
144      if (TimerList == NULL)	/* Last one ? */
145	timer_TermService();	/* Terminate Timer Service */
146    }
147    if (t->next) {
148      if (!pt) {		/* t (tp) was the first in the list */
149        struct itimerval itimer;
150
151        if (getitimer(ITIMER_REAL, &itimer) == 0)
152          t->rest = RESTVAL(itimer);
153      }
154      t->next->rest += t->rest;
155      if (!pt)			/* t->next is now the first in the list */
156        timer_InitService(1);
157    }
158  } else {
159    /* Search for any pending expired timers */
160    pt = NULL;
161    for (t = ExpiredList; t != tp && t != NULL; t = t->enext)
162      pt = t;
163
164    if (t) {
165      if (pt)
166        pt->enext = t->enext;
167      else
168        ExpiredList = t->enext;
169    } else if (tp->state == TIMER_RUNNING)
170      log_Printf(LogERROR, "Oops, %s timer not found!!\n", tp->name);
171  }
172
173  tp->next = tp->enext = NULL;
174  tp->state = TIMER_STOPPED;
175}
176
177static void
178TimerService(void)
179{
180  struct pppTimer *tp, *exp, *next;
181
182  if (log_IsKept(LogTIMER)) {
183    static time_t t;		/* Only show timers globally every second */
184    time_t n = time(NULL);
185
186    if (n > t)
187      timer_Show(LogTIMER, NULL);
188    t = n;
189  }
190
191  tp = TimerList;
192  if (tp) {
193    tp->rest = 0;
194
195    /* Multiple timers might expire at once. Create a list of expired timers */
196    exp = NULL;
197    do {
198      tp->state = TIMER_EXPIRED;
199      next = tp->next;
200      tp->enext = exp;
201      exp = tp;
202      tp = next;
203    } while (tp && tp->rest == 0);
204
205    TimerList = tp;
206    if (TimerList != NULL)	/* Any timers remaining ? */
207      timer_InitService(1);	/* Restart the Timer Service */
208    else
209      timer_TermService();	/* Stop the Timer Service */
210
211    /* Process all expired timers */
212    while (exp) {
213      ExpiredList = exp->enext;
214      exp->enext = NULL;
215      if (exp->func)
216        (*exp->func)(exp->arg);
217      exp = ExpiredList;
218    }
219  }
220}
221
222void
223timer_Show(int LogLevel, struct prompt *prompt)
224{
225  struct itimerval itimer;
226  struct pppTimer *pt;
227  u_long rest = 0;
228
229  /* Adjust our first delta so that it reflects what's really happening */
230  if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
231    TimerList->rest = RESTVAL(itimer);
232
233#define SECS(val)	((val) / SECTICKS)
234#define HSECS(val)	(((val) % SECTICKS) * 100 / SECTICKS)
235#define DISP								\
236  "%s timer[%p]: freq = %ld.%02lds, next = %lu.%02lus, state = %s\n",	\
237  pt->name, pt, SECS(pt->load), HSECS(pt->load), SECS(rest),		\
238  HSECS(rest), tState2Nam(pt->state)
239
240  if (!prompt)
241    log_Printf(LogLevel, "---- Begin of Timer Service List---\n");
242
243  for (pt = TimerList; pt; pt = pt->next) {
244    rest += pt->rest;
245    if (prompt)
246      prompt_Printf(prompt, DISP);
247    else
248      log_Printf(LogLevel, DISP);
249  }
250
251  if (!prompt)
252    log_Printf(LogLevel, "---- End of Timer Service List ---\n");
253}
254
255void
256timer_InitService(int restart)
257{
258  struct itimerval itimer;
259
260  if (TimerList) {
261    if (!restart)
262      sig_signal(SIGALRM, (void (*)(int))TimerService);
263    itimer.it_interval.tv_sec = 0;
264    itimer.it_interval.tv_usec = 0;
265    itimer.it_value.tv_sec = TimerList->rest / SECTICKS;
266    itimer.it_value.tv_usec = (TimerList->rest % SECTICKS) * TICKUNIT;
267    if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
268      log_Printf(LogERROR, "Unable to set itimer (%s)\n", strerror(errno));
269  }
270}
271
272void
273timer_TermService(void)
274{
275  struct itimerval itimer;
276
277  itimer.it_interval.tv_usec = itimer.it_interval.tv_sec = 0;
278  itimer.it_value.tv_usec = itimer.it_value.tv_sec = 0;
279  if (setitimer(ITIMER_REAL, &itimer, NULL) == -1)
280    log_Printf(LogERROR, "Unable to set itimer (%s)\n", strerror(errno));
281  sig_signal(SIGALRM, SIG_IGN);
282}
283