1 /* Quagga signal handling functions.
2 * Copyright (C) 2004 Paul Jakma,
4 * This file is part of Quagga.
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
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.
16 * You should have received a copy of the GNU General Public License along
17 * with this program; see the file COPYING; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
25 #include <lib_errors.h>
27 #ifdef HAVE_UCONTEXT_H
29 /* get REG_EIP from ucontext.h */
32 #endif /* __USE_GNU */
33 #endif /* GNU_LINUX */
35 #endif /* HAVE_UCONTEXT_H */
38 /* master signals descriptor struct */
39 static struct quagga_sigevent_master_t
{
42 struct quagga_signal_t
*signals
;
45 volatile sig_atomic_t caught
;
48 /* Generic signal handler
49 * Schedules signal event thread
51 static void quagga_signal_handler(int signo
)
54 struct quagga_signal_t
*sig
;
56 for (i
= 0; i
< sigmaster
.sigc
; i
++) {
57 sig
= &(sigmaster
.signals
[i
]);
59 if (sig
->signal
== signo
)
66 /* check if signals have been caught and run appropriate handlers */
67 int quagga_sigevent_process(void)
69 struct quagga_signal_t
*sig
;
71 #ifdef SIGEVENT_BLOCK_SIGNALS
72 /* shouldnt need to block signals, but potentially may be needed */
73 sigset_t newmask
, oldmask
;
76 * Block most signals, but be careful not to defer SIGTRAP because
77 * doing so breaks gdb, at least on NetBSD 2.0. Avoid asking to
78 * block SIGKILL, just because we shouldn't be able to do so.
81 sigdelset(&newmask
, SIGTRAP
);
82 sigdelset(&newmask
, SIGKILL
);
84 if ((sigprocmask(SIG_BLOCK
, &newmask
, &oldmask
)) < 0) {
85 flog_err_sys(EC_LIB_SYSTEM_CALL
,
86 "quagga_signal_timer: couldnt block signals!");
89 #endif /* SIGEVENT_BLOCK_SIGNALS */
91 if (sigmaster
.caught
> 0) {
93 /* must not read or set sigmaster.caught after here,
94 * race condition with per-sig caught flags if one does
97 for (i
= 0; i
< sigmaster
.sigc
; i
++) {
98 sig
= &(sigmaster
.signals
[i
]);
100 if (sig
->caught
> 0) {
108 #ifdef SIGEVENT_BLOCK_SIGNALS
109 if (sigprocmask(SIG_UNBLOCK
, &oldmask
, NULL
) < 0)
112 #endif /* SIGEVENT_BLOCK_SIGNALS */
117 #ifdef SIGEVENT_SCHEDULE_THREAD
118 /* timer thread to check signals. Shouldnt be needed */
119 int quagga_signal_timer(struct thread
*t
)
121 struct quagga_sigevent_master_t
*sigm
;
123 sigm
= THREAD_ARG(t
);
125 thread_add_timer(sigm
->t
->master
, quagga_signal_timer
, &sigmaster
,
126 QUAGGA_SIGNAL_TIMER_INTERVAL
, &sigm
->t
);
127 return quagga_sigevent_process();
129 #endif /* SIGEVENT_SCHEDULE_THREAD */
131 /* Initialization of signal handles. */
132 /* Signal wrapper. */
133 static int signal_set(int signo
)
136 struct sigaction sig
;
137 struct sigaction osig
;
139 sig
.sa_handler
= &quagga_signal_handler
;
140 sigfillset(&sig
.sa_mask
);
142 if (signo
== SIGALRM
) {
144 sig
.sa_flags
|= SA_INTERRUPT
; /* SunOS */
148 sig
.sa_flags
|= SA_RESTART
;
149 #endif /* SA_RESTART */
152 ret
= sigaction(signo
, &sig
, &osig
);
159 /* XXX This function should be enhanced to support more platforms
160 (it currently works only on Linux/x86). */
161 static void *program_counter(void *context
)
163 #ifdef HAVE_UCONTEXT_H
165 /* these are from GNU libc, rather than Linux, strictly speaking */
167 # define REG_INDEX REG_EIP
168 #elif defined(REG_RIP)
169 # define REG_INDEX REG_RIP
170 #elif defined(__powerpc__)
171 # define REG_INDEX 32
173 #elif defined(SUNOS_5) /* !GNU_LINUX */
174 # define REG_INDEX REG_PC
175 #endif /* GNU_LINUX */
178 #ifdef HAVE_UCONTEXT_T_UC_MCONTEXT_GREGS
179 # define REGS gregs[REG_INDEX]
180 #elif defined(HAVE_UCONTEXT_T_UC_MCONTEXT_UC_REGS)
181 # define REGS uc_regs->gregs[REG_INDEX]
182 #endif /* HAVE_UCONTEXT_T_UC_MCONTEXT_GREGS */
183 #endif /* REG_INDEX */
187 return (void *)(((ucontext_t
*)context
)->uc_mcontext
.REGS
);
188 #elif defined(HAVE_UCONTEXT_T_UC_MCONTEXT_REGS__NIP)
189 /* older Linux / struct pt_regs ? */
191 return (void *)(((ucontext_t
*)context
)->uc_mcontext
.regs
->nip
);
194 #endif /* HAVE_UCONTEXT_H */
198 static void __attribute__((noreturn
))
199 exit_handler(int signo
, siginfo_t
*siginfo
, void *context
)
201 void *pc
= program_counter(context
);
203 zlog_signal(signo
, "exiting...", siginfo
, pc
);
207 static void __attribute__((noreturn
))
208 core_handler(int signo
, siginfo_t
*siginfo
, void *context
)
210 void *pc
= program_counter(context
);
212 /* make sure we don't hang in here. default for SIGALRM is terminate.
213 * - if we're in backtrace for more than a second, abort. */
214 struct sigaction sa_default
= {.sa_handler
= SIG_DFL
};
215 sigaction(SIGALRM
, &sa_default
, NULL
);
218 sigemptyset(&sigset
);
219 sigaddset(&sigset
, SIGALRM
);
220 sigprocmask(SIG_UNBLOCK
, &sigset
, NULL
);
224 zlog_signal(signo
, "aborting...", siginfo
, pc
);
226 /* dump memory stats on core */
227 log_memstats(stderr
, "core_handler");
231 static void trap_default_signals(void)
233 static const int core_signals
[] = {
238 SIGFPE
, SIGBUS
, SIGSEGV
,
249 static const int exit_signals
[] = {
250 SIGHUP
, SIGINT
, SIGALRM
, SIGTERM
, SIGUSR1
, SIGUSR2
,
261 static const int ignore_signals
[] = {
264 static const struct {
267 void (*handler
)(int signo
, siginfo_t
*info
, void *context
);
269 {core_signals
, array_size(core_signals
), core_handler
},
270 {exit_signals
, array_size(exit_signals
), exit_handler
},
271 {ignore_signals
, array_size(ignore_signals
), NULL
},
275 for (i
= 0; i
< array_size(sigmap
); i
++) {
278 for (j
= 0; j
< sigmap
[i
].nsigs
; j
++) {
279 struct sigaction oact
;
280 if ((sigaction(sigmap
[i
].sigs
[j
], NULL
, &oact
) == 0)
281 && (oact
.sa_handler
== SIG_DFL
)) {
282 struct sigaction act
;
283 sigfillset(&act
.sa_mask
);
284 if (sigmap
[i
].handler
== NULL
) {
285 act
.sa_handler
= SIG_IGN
;
288 /* Request extra arguments to signal
290 act
.sa_sigaction
= sigmap
[i
].handler
;
291 act
.sa_flags
= SA_SIGINFO
;
293 /* don't try to print backtraces
295 if (sigmap
[i
].handler
== core_handler
)
296 act
.sa_flags
|= SA_RESETHAND
;
299 if (sigaction(sigmap
[i
].sigs
[j
], &act
, NULL
)
303 "Unable to set signal handler for signal %d: %s",
305 safe_strerror(errno
));
311 void signal_init(struct thread_master
*m
, int sigc
,
312 struct quagga_signal_t signals
[])
316 struct quagga_signal_t
*sig
;
318 /* First establish some default handlers that can be overridden by
320 trap_default_signals();
324 if (signal_set(sig
->signal
) < 0)
329 sigmaster
.sigc
= sigc
;
330 sigmaster
.signals
= signals
;
332 #ifdef SIGEVENT_SCHEDULE_THREAD
334 thread_add_timer(m
, quagga_signal_timer
, &sigmaster
,
335 QUAGGA_SIGNAL_TIMER_INTERVAL
, &sigmaster
.t
);
336 #endif /* SIGEVENT_SCHEDULE_THREAD */