Annotation of embedaddon/quagga/lib/sigevent.c, revision 1.1.1.1
1.1 misho 1: /* Quagga signal handling functions.
2: * Copyright (C) 2004 Paul Jakma,
3: *
4: * This file is part of Quagga.
5: *
6: * Quagga is free software; you can redistribute it and/or modify it
7: * under the terms of the GNU General Public License as published by the
8: * Free Software Foundation; either version 2, or (at your option) any
9: * later version.
10: *
11: * Quagga is distributed in the hope that it will be useful, but
12: * WITHOUT ANY WARRANTY; without even the implied warranty of
13: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14: * General Public License for more details.
15: *
16: * You should have received a copy of the GNU General Public License
17: * along with Quagga; see the file COPYING. If not, write to the Free
18: * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
19: * 02111-1307, USA.
20: */
21:
22: #include <zebra.h>
23: #include <sigevent.h>
24: #include <log.h>
25:
26: #ifdef SA_SIGINFO
27: #ifdef HAVE_UCONTEXT_H
28: #ifdef GNU_LINUX
29: /* get REG_EIP from ucontext.h */
30: #ifndef __USE_GNU
31: #define __USE_GNU
32: #endif /* __USE_GNU */
33: #endif /* GNU_LINUX */
34: #include <ucontext.h>
35: #endif /* HAVE_UCONTEXT_H */
36: #endif /* SA_SIGINFO */
37:
38:
39: /* master signals descriptor struct */
40: struct quagga_sigevent_master_t
41: {
42: struct thread *t;
43:
44: struct quagga_signal_t *signals;
45: int sigc;
46:
47: volatile sig_atomic_t caught;
48: } sigmaster;
49:
50: /* Generic signal handler
51: * Schedules signal event thread
52: */
53: static void
54: quagga_signal_handler (int signo)
55: {
56: int i;
57: struct quagga_signal_t *sig;
58:
59: for (i = 0; i < sigmaster.sigc; i++)
60: {
61: sig = &(sigmaster.signals[i]);
62:
63: if (sig->signal == signo)
64: sig->caught = 1;
65: }
66:
67: sigmaster.caught = 1;
68: }
69:
70: /* check if signals have been caught and run appropriate handlers */
71: int
72: quagga_sigevent_process (void)
73: {
74: struct quagga_signal_t *sig;
75: int i;
76: #ifdef SIGEVENT_BLOCK_SIGNALS
77: /* shouldnt need to block signals, but potentially may be needed */
78: sigset_t newmask, oldmask;
79:
80: /*
81: * Block most signals, but be careful not to defer SIGTRAP because
82: * doing so breaks gdb, at least on NetBSD 2.0. Avoid asking to
83: * block SIGKILL, just because we shouldn't be able to do so.
84: */
85: sigfillset (&newmask);
86: sigdelset (&newmask, SIGTRAP);
87: sigdelset (&newmask, SIGKILL);
88:
89: if ( (sigprocmask (SIG_BLOCK, &newmask, &oldmask)) < 0)
90: {
91: zlog_err ("quagga_signal_timer: couldnt block signals!");
92: return -1;
93: }
94: #endif /* SIGEVENT_BLOCK_SIGNALS */
95:
96: if (sigmaster.caught > 0)
97: {
98: sigmaster.caught = 0;
99: /* must not read or set sigmaster.caught after here,
100: * race condition with per-sig caught flags if one does
101: */
102:
103: for (i = 0; i < sigmaster.sigc; i++)
104: {
105: sig = &(sigmaster.signals[i]);
106:
107: if (sig->caught > 0)
108: {
109: sig->caught = 0;
110: sig->handler ();
111: }
112: }
113: }
114:
115: #ifdef SIGEVENT_BLOCK_SIGNALS
116: if ( sigprocmask (SIG_UNBLOCK, &oldmask, NULL) < 0 );
117: return -1;
118: #endif /* SIGEVENT_BLOCK_SIGNALS */
119:
120: return 0;
121: }
122:
123: #ifdef SIGEVENT_SCHEDULE_THREAD
124: /* timer thread to check signals. Shouldnt be needed */
125: int
126: quagga_signal_timer (struct thread *t)
127: {
128: struct quagga_sigevent_master_t *sigm;
129: struct quagga_signal_t *sig;
130: int i;
131:
132: sigm = THREAD_ARG (t);
133: sigm->t = thread_add_timer (sigm->t->master, quagga_signal_timer, &sigmaster,
134: QUAGGA_SIGNAL_TIMER_INTERVAL);
135: return quagga_sigevent_process ();
136: }
137: #endif /* SIGEVENT_SCHEDULE_THREAD */
138:
139: /* Initialization of signal handles. */
140: /* Signal wrapper. */
141: static int
142: signal_set (int signo)
143: {
144: int ret;
145: struct sigaction sig;
146: struct sigaction osig;
147:
148: sig.sa_handler = &quagga_signal_handler;
149: sigfillset (&sig.sa_mask);
150: sig.sa_flags = 0;
151: if (signo == SIGALRM) {
152: #ifdef SA_INTERRUPT
153: sig.sa_flags |= SA_INTERRUPT; /* SunOS */
154: #endif
155: } else {
156: #ifdef SA_RESTART
157: sig.sa_flags |= SA_RESTART;
158: #endif /* SA_RESTART */
159: }
160:
161: ret = sigaction (signo, &sig, &osig);
162: if (ret < 0)
163: return ret;
164: else
165: return 0;
166: }
167:
168: #ifdef SA_SIGINFO
169:
170: /* XXX This function should be enhanced to support more platforms
171: (it currently works only on Linux/x86). */
172: static void *
173: program_counter(void *context)
174: {
175: #ifdef HAVE_UCONTEXT_H
176: #ifdef GNU_LINUX
177: #ifdef REG_EIP
178: if (context)
179: return (void *)(((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP]);
180: #endif /* REG_EIP */
181: #endif /* GNU_LINUX */
182: #endif /* HAVE_UCONTEXT_H */
183: return NULL;
184: }
185:
186: #endif /* SA_SIGINFO */
187:
188: static void __attribute__ ((noreturn))
189: exit_handler(int signo
190: #ifdef SA_SIGINFO
191: , siginfo_t *siginfo, void *context
192: #endif
193: )
194: {
195: zlog_signal(signo, "exiting..."
196: #ifdef SA_SIGINFO
197: , siginfo, program_counter(context)
198: #endif
199: );
200: _exit(128+signo);
201: }
202:
203: static void __attribute__ ((noreturn))
204: core_handler(int signo
205: #ifdef SA_SIGINFO
206: , siginfo_t *siginfo, void *context
207: #endif
208: )
209: {
210: zlog_signal(signo, "aborting..."
211: #ifdef SA_SIGINFO
212: , siginfo, program_counter(context)
213: #endif
214: );
215: abort();
216: }
217:
218: static void
219: trap_default_signals(void)
220: {
221: static const int core_signals[] = {
222: SIGQUIT,
223: SIGILL,
224: #ifdef SIGEMT
225: SIGEMT,
226: #endif
227: SIGFPE,
228: SIGBUS,
229: SIGSEGV,
230: #ifdef SIGSYS
231: SIGSYS,
232: #endif
233: #ifdef SIGXCPU
234: SIGXCPU,
235: #endif
236: #ifdef SIGXFSZ
237: SIGXFSZ,
238: #endif
239: };
240: static const int exit_signals[] = {
241: SIGHUP,
242: SIGINT,
243: SIGALRM,
244: SIGTERM,
245: SIGUSR1,
246: SIGUSR2,
247: #ifdef SIGPOLL
248: SIGPOLL,
249: #endif
250: #ifdef SIGVTALRM
251: SIGVTALRM,
252: #endif
253: #ifdef SIGSTKFLT
254: SIGSTKFLT,
255: #endif
256: };
257: static const int ignore_signals[] = {
258: SIGPIPE,
259: };
260: static const struct {
261: const int *sigs;
262: u_int nsigs;
263: void (*handler)(int signo
264: #ifdef SA_SIGINFO
265: , siginfo_t *info, void *context
266: #endif
267: );
268: } sigmap[] = {
269: { core_signals, sizeof(core_signals)/sizeof(core_signals[0]), core_handler},
270: { exit_signals, sizeof(exit_signals)/sizeof(exit_signals[0]), exit_handler},
271: { ignore_signals, sizeof(ignore_signals)/sizeof(ignore_signals[0]), NULL},
272: };
273: u_int i;
274:
275: for (i = 0; i < sizeof(sigmap)/sizeof(sigmap[0]); i++)
276: {
277: u_int j;
278:
279: for (j = 0; j < sigmap[i].nsigs; j++)
280: {
281: struct sigaction oact;
282: if ((sigaction(sigmap[i].sigs[j],NULL,&oact) == 0) &&
283: (oact.sa_handler == SIG_DFL))
284: {
285: struct sigaction act;
286: sigfillset (&act.sa_mask);
287: if (sigmap[i].handler == NULL)
288: {
289: act.sa_handler = SIG_IGN;
290: act.sa_flags = 0;
291: }
292: else
293: {
294: #ifdef SA_SIGINFO
295: /* Request extra arguments to signal handler. */
296: act.sa_sigaction = sigmap[i].handler;
297: act.sa_flags = SA_SIGINFO;
298: #else
299: act.sa_handler = sigmap[i].handler;
300: act.sa_flags = 0;
301: #endif
302: }
303: if (sigaction(sigmap[i].sigs[j],&act,NULL) < 0)
304: zlog_warn("Unable to set signal handler for signal %d: %s",
305: sigmap[i].sigs[j],safe_strerror(errno));
306:
307: }
308: }
309: }
310: }
311:
312: void
313: signal_init (struct thread_master *m, int sigc,
314: struct quagga_signal_t signals[])
315: {
316:
317: int i = 0;
318: struct quagga_signal_t *sig;
319:
320: /* First establish some default handlers that can be overridden by
321: the application. */
322: trap_default_signals();
323:
324: while (i < sigc)
325: {
326: sig = &signals[i];
327: if ( signal_set (sig->signal) < 0 )
328: exit (-1);
329: i++;
330: }
331:
332: sigmaster.sigc = sigc;
333: sigmaster.signals = signals;
334:
335: #ifdef SIGEVENT_SCHEDULE_THREAD
336: sigmaster.t =
337: thread_add_timer (m, quagga_signal_timer, &sigmaster,
338: QUAGGA_SIGNAL_TIMER_INTERVAL);
339: #endif /* SIGEVENT_SCHEDULE_THREAD */
340: }
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