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Date:: Sat Apr 1 19:24:03 2006 UTC
Message:: Use gcc -ansi -pedantic in 9c. Fix many non-C89-isms.
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  1 9acaad45 2004-10-23 devnull /*
  2 9acaad45 2004-10-23 devnull  * Signal handling for Plan 9 programs. 
  3 9acaad45 2004-10-23 devnull  * We stubbornly use the strings from Plan 9 instead 
  4 9acaad45 2004-10-23 devnull  * of the enumerated Unix constants.  
  5 9acaad45 2004-10-23 devnull  * There are some weird translations.  In particular,
  6 9acaad45 2004-10-23 devnull  * a "kill" note is the same as SIGTERM in Unix.
  7 9acaad45 2004-10-23 devnull  * There is no equivalent note to Unix's SIGKILL, since
  8 9acaad45 2004-10-23 devnull  * it's not a deliverable signal anyway.
  9 9acaad45 2004-10-23 devnull  *
 10 5f8fa947 2004-12-26 devnull  * We do not handle SIGABRT or SIGSEGV, mainly because
 11 5f8fa947 2004-12-26 devnull  * the thread library queues its notes for later, and we want
 12 5f8fa947 2004-12-26 devnull  * to dump core with the state at time of delivery.
 13 9acaad45 2004-10-23 devnull  *
 14 9acaad45 2004-10-23 devnull  * We have to add some extra entry points to provide the
 15 9acaad45 2004-10-23 devnull  * ability to tweak which signals are deliverable and which
 16 9acaad45 2004-10-23 devnull  * are acted upon.  Notifydisable and notifyenable play with
 17 9acaad45 2004-10-23 devnull  * the process signal mask.  Notifyignore enables the signal
 18 9acaad45 2004-10-23 devnull  * but will not call notifyf when it comes in.  This is occasionally
 19 9acaad45 2004-10-23 devnull  * useful.
 20 9acaad45 2004-10-23 devnull  */
 21 9acaad45 2004-10-23 devnull 
 22 fd04aace 2003-11-23 devnull #include <u.h>
 23 8ad51794 2004-03-25 devnull #include <signal.h>
 24 fd04aace 2003-11-23 devnull #define NOPLAN9DEFINES
 25 fd04aace 2003-11-23 devnull #include <libc.h>
 26 fd04aace 2003-11-23 devnull 
 27 fd04aace 2003-11-23 devnull extern char *_p9sigstr(int, char*);
 28 9acaad45 2004-10-23 devnull extern int _p9strsig(char*);
 29 fd04aace 2003-11-23 devnull 
 30 9acaad45 2004-10-23 devnull typedef struct Sig Sig;
 31 9acaad45 2004-10-23 devnull struct Sig
 32 9acaad45 2004-10-23 devnull {
 33 9acaad45 2004-10-23 devnull 	int sig;			/* signal number */
 34 f3ecd8ae 2005-02-08 devnull 	int flags;
 35 9acaad45 2004-10-23 devnull };
 36 9acaad45 2004-10-23 devnull 
 37 f3ecd8ae 2005-02-08 devnull enum
 38 f3ecd8ae 2005-02-08 devnull {
 39 f3ecd8ae 2005-02-08 devnull 	Restart = 1<<0,
 40 cbeb0b26 2006-04-01 devnull 	Ignore = 1<<1
 41 f3ecd8ae 2005-02-08 devnull };
 42 10f14b04 2005-01-16 devnull 
 43 9acaad45 2004-10-23 devnull static Sig sigs[] = {
 44 f3ecd8ae 2005-02-08 devnull 	SIGHUP,		0,
 45 f3ecd8ae 2005-02-08 devnull 	SIGINT,		0,
 46 f3ecd8ae 2005-02-08 devnull 	SIGQUIT,		0,
 47 f3ecd8ae 2005-02-08 devnull 	SIGILL,		0,
 48 f3ecd8ae 2005-02-08 devnull 	SIGTRAP,		0,
 49 f3ecd8ae 2005-02-08 devnull /*	SIGABRT, 		0, 	*/
 50 d2c4ee9e 2003-11-24 devnull #ifdef SIGEMT
 51 f3ecd8ae 2005-02-08 devnull 	SIGEMT,		0,
 52 d2c4ee9e 2003-11-24 devnull #endif
 53 f3ecd8ae 2005-02-08 devnull 	SIGFPE,		0,
 54 f3ecd8ae 2005-02-08 devnull 	SIGBUS,		0,
 55 f3ecd8ae 2005-02-08 devnull /*	SIGSEGV, 		0, 	*/
 56 f3ecd8ae 2005-02-08 devnull 	SIGCHLD,		Restart|Ignore,
 57 f3ecd8ae 2005-02-08 devnull 	SIGSYS,		0,
 58 f3ecd8ae 2005-02-08 devnull 	SIGPIPE,		Ignore,
 59 f3ecd8ae 2005-02-08 devnull 	SIGALRM,		0,
 60 f3ecd8ae 2005-02-08 devnull 	SIGTERM,		0,
 61 f3ecd8ae 2005-02-08 devnull 	SIGTSTP,		Restart|Ignore,
 62 1dd11f59 2005-03-18 devnull /*	SIGTTIN,		Restart|Ignore, */
 63 1dd11f59 2005-03-18 devnull /*	SIGTTOU,		Restart|Ignore, */
 64 f3ecd8ae 2005-02-08 devnull 	SIGXCPU,		0,
 65 f3ecd8ae 2005-02-08 devnull 	SIGXFSZ,		0,
 66 f3ecd8ae 2005-02-08 devnull 	SIGVTALRM,	0,
 67 f3ecd8ae 2005-02-08 devnull 	SIGUSR1,		0,
 68 f3ecd8ae 2005-02-08 devnull 	SIGUSR2,		0,
 69 bc7da029 2005-05-07 devnull #ifdef SIGWINCH
 70 f3ecd8ae 2005-02-08 devnull 	SIGWINCH,	Restart|Ignore,
 71 bc7da029 2005-05-07 devnull #endif
 72 d2c4ee9e 2003-11-24 devnull #ifdef SIGINFO
 73 f3ecd8ae 2005-02-08 devnull 	SIGINFO,		Restart|Ignore,
 74 d2c4ee9e 2003-11-24 devnull #endif
 75 fd04aace 2003-11-23 devnull };
 76 fd04aace 2003-11-23 devnull 
 77 9acaad45 2004-10-23 devnull static Sig*
 78 9acaad45 2004-10-23 devnull findsig(int s)
 79 9acaad45 2004-10-23 devnull {
 80 9acaad45 2004-10-23 devnull 	int i;
 81 9acaad45 2004-10-23 devnull 
 82 9acaad45 2004-10-23 devnull 	for(i=0; i<nelem(sigs); i++)
 83 9acaad45 2004-10-23 devnull 		if(sigs[i].sig == s)
 84 9acaad45 2004-10-23 devnull 			return &sigs[i];
 85 9acaad45 2004-10-23 devnull 	return nil;
 86 9acaad45 2004-10-23 devnull }
 87 9acaad45 2004-10-23 devnull 
 88 9acaad45 2004-10-23 devnull /*
 89 9acaad45 2004-10-23 devnull  * The thread library initializes _notejmpbuf to its own
 90 9acaad45 2004-10-23 devnull  * routine which provides a per-pthread jump buffer.
 91 9acaad45 2004-10-23 devnull  * If we're not using the thread library, we assume we are
 92 9acaad45 2004-10-23 devnull  * single-threaded.
 93 9acaad45 2004-10-23 devnull  */
 94 05d8c6df 2004-09-23 devnull typedef struct Jmp Jmp;
 95 05d8c6df 2004-09-23 devnull struct Jmp
 96 05d8c6df 2004-09-23 devnull {
 97 05d8c6df 2004-09-23 devnull 	p9jmp_buf b;
 98 05d8c6df 2004-09-23 devnull };
 99 05d8c6df 2004-09-23 devnull 
100 05d8c6df 2004-09-23 devnull static Jmp onejmp;
101 05d8c6df 2004-09-23 devnull 
102 05d8c6df 2004-09-23 devnull static Jmp*
103 05d8c6df 2004-09-23 devnull getonejmp(void)
104 05d8c6df 2004-09-23 devnull {
105 05d8c6df 2004-09-23 devnull 	return &onejmp;
106 05d8c6df 2004-09-23 devnull }
107 05d8c6df 2004-09-23 devnull 
108 05d8c6df 2004-09-23 devnull Jmp *(*_notejmpbuf)(void) = getonejmp;
109 9acaad45 2004-10-23 devnull static void noteinit(void);
110 fd04aace 2003-11-23 devnull 
111 9acaad45 2004-10-23 devnull /*
112 9acaad45 2004-10-23 devnull  * Actual signal handler. 
113 9acaad45 2004-10-23 devnull  */
114 aa200fe3 2004-10-22 devnull 
115 9acaad45 2004-10-23 devnull static void (*notifyf)(void*, char*);	/* Plan 9 handler */
116 9acaad45 2004-10-23 devnull 
117 aa200fe3 2004-10-22 devnull static void
118 9acaad45 2004-10-23 devnull signotify(int sig)
119 fd04aace 2003-11-23 devnull {
120 fd04aace 2003-11-23 devnull 	char tmp[64];
121 05d8c6df 2004-09-23 devnull 	Jmp *j;
122 f3ecd8ae 2005-02-08 devnull 	Sig *s;
123 fd04aace 2003-11-23 devnull 
124 05d8c6df 2004-09-23 devnull 	j = (*_notejmpbuf)();
125 9acaad45 2004-10-23 devnull 	switch(p9setjmp(j->b)){
126 9acaad45 2004-10-23 devnull 	case 0:
127 9acaad45 2004-10-23 devnull 		if(notifyf)
128 9acaad45 2004-10-23 devnull 			(*notifyf)(nil, _p9sigstr(sig, tmp));
129 9acaad45 2004-10-23 devnull 		/* fall through */
130 9acaad45 2004-10-23 devnull 	case 1:	/* noted(NDFLT) */
131 9acaad45 2004-10-23 devnull 		if(0)print("DEFAULT %d\n", sig);
132 f3ecd8ae 2005-02-08 devnull 		s = findsig(sig);
133 f3ecd8ae 2005-02-08 devnull 		if(s && (s->flags&Ignore))
134 f3ecd8ae 2005-02-08 devnull 			return;
135 9acaad45 2004-10-23 devnull 		signal(sig, SIG_DFL);
136 9acaad45 2004-10-23 devnull 		raise(sig);
137 9acaad45 2004-10-23 devnull 		_exit(1);
138 9acaad45 2004-10-23 devnull 	case 2:	/* noted(NCONT) */
139 05d8c6df 2004-09-23 devnull 		if(0)print("HANDLED %d\n", sig);
140 fd04aace 2003-11-23 devnull 		return;
141 fd04aace 2003-11-23 devnull 	}
142 fd04aace 2003-11-23 devnull }
143 05d8c6df 2004-09-23 devnull 
144 9acaad45 2004-10-23 devnull static void
145 9acaad45 2004-10-23 devnull signonotify(int sig)
146 9acaad45 2004-10-23 devnull {
147 9acaad45 2004-10-23 devnull 	USED(sig);
148 9acaad45 2004-10-23 devnull }
149 9acaad45 2004-10-23 devnull 
150 fd04aace 2003-11-23 devnull int
151 05d8c6df 2004-09-23 devnull noted(int v)
152 05d8c6df 2004-09-23 devnull {
153 05d8c6df 2004-09-23 devnull 	p9longjmp((*_notejmpbuf)()->b, v==NCONT ? 2 : 1);
154 05d8c6df 2004-09-23 devnull 	abort();
155 05d8c6df 2004-09-23 devnull 	return 0;
156 05d8c6df 2004-09-23 devnull }
157 05d8c6df 2004-09-23 devnull 
158 9acaad45 2004-10-23 devnull int
159 9acaad45 2004-10-23 devnull notify(void (*f)(void*, char*))
160 9acaad45 2004-10-23 devnull {
161 9acaad45 2004-10-23 devnull 	static int init;
162 9acaad45 2004-10-23 devnull 
163 9acaad45 2004-10-23 devnull 	notifyf = f;
164 9acaad45 2004-10-23 devnull 	if(!init){
165 9acaad45 2004-10-23 devnull 		init = 1;
166 9acaad45 2004-10-23 devnull 		noteinit();
167 9acaad45 2004-10-23 devnull 	}
168 9acaad45 2004-10-23 devnull 	return 0;
169 9acaad45 2004-10-23 devnull }
170 9acaad45 2004-10-23 devnull 
171 9acaad45 2004-10-23 devnull /*
172 9acaad45 2004-10-23 devnull  * Nonsense about enabling and disabling signals.
173 9acaad45 2004-10-23 devnull  */
174 5f8fa947 2004-12-26 devnull typedef void Sighandler(int);
175 5f8fa947 2004-12-26 devnull static Sighandler*
176 9acaad45 2004-10-23 devnull handler(int s)
177 9acaad45 2004-10-23 devnull {
178 9acaad45 2004-10-23 devnull 	struct sigaction sa;
179 9acaad45 2004-10-23 devnull 
180 9acaad45 2004-10-23 devnull 	sigaction(s, nil, &sa);
181 9acaad45 2004-10-23 devnull 	return sa.sa_handler;
182 9acaad45 2004-10-23 devnull }
183 9acaad45 2004-10-23 devnull 
184 10f14b04 2005-01-16 devnull static int
185 5f8fa947 2004-12-26 devnull notesetenable(int sig, int enabled)
186 fd04aace 2003-11-23 devnull {
187 10f14b04 2005-01-16 devnull 	sigset_t mask, omask;
188 fd04aace 2003-11-23 devnull 
189 9acaad45 2004-10-23 devnull 	if(sig == 0)
190 10f14b04 2005-01-16 devnull 		return -1;
191 aa200fe3 2004-10-22 devnull 
192 9acaad45 2004-10-23 devnull 	sigemptyset(&mask);
193 9acaad45 2004-10-23 devnull 	sigaddset(&mask, sig);
194 10f14b04 2005-01-16 devnull 	sigprocmask(enabled ? SIG_UNBLOCK : SIG_BLOCK, &mask, &omask);
195 10f14b04 2005-01-16 devnull 	return !sigismember(&omask, sig);	
196 9acaad45 2004-10-23 devnull }
197 9acaad45 2004-10-23 devnull 
198 10f14b04 2005-01-16 devnull int
199 5f8fa947 2004-12-26 devnull noteenable(char *msg)
200 9acaad45 2004-10-23 devnull {
201 10f14b04 2005-01-16 devnull 	return notesetenable(_p9strsig(msg), 1);
202 9acaad45 2004-10-23 devnull }
203 9acaad45 2004-10-23 devnull 
204 10f14b04 2005-01-16 devnull int
205 5f8fa947 2004-12-26 devnull notedisable(char *msg)
206 9acaad45 2004-10-23 devnull {
207 10f14b04 2005-01-16 devnull 	return notesetenable(_p9strsig(msg), 0);
208 9acaad45 2004-10-23 devnull }
209 9acaad45 2004-10-23 devnull 
210 10f14b04 2005-01-16 devnull static int
211 9acaad45 2004-10-23 devnull notifyseton(int s, int on)
212 9acaad45 2004-10-23 devnull {
213 9acaad45 2004-10-23 devnull 	Sig *sig;
214 10f14b04 2005-01-16 devnull 	struct sigaction sa, osa;
215 9acaad45 2004-10-23 devnull 
216 9acaad45 2004-10-23 devnull 	sig = findsig(s);
217 9acaad45 2004-10-23 devnull 	if(sig == nil)
218 10f14b04 2005-01-16 devnull 		return -1;
219 669250d1 2003-12-03 devnull 	memset(&sa, 0, sizeof sa);
220 9acaad45 2004-10-23 devnull 	sa.sa_handler = on ? signotify : signonotify;
221 f3ecd8ae 2005-02-08 devnull 	if(sig->flags&Restart)
222 9acaad45 2004-10-23 devnull 		sa.sa_flags |= SA_RESTART;
223 aa200fe3 2004-10-22 devnull 
224 aa200fe3 2004-10-22 devnull 	/*
225 9acaad45 2004-10-23 devnull 	 * We can't allow signals within signals because there's
226 9acaad45 2004-10-23 devnull 	 * only one jump buffer.
227 aa200fe3 2004-10-22 devnull 	 */
228 aa200fe3 2004-10-22 devnull 	sigfillset(&sa.sa_mask);
229 9acaad45 2004-10-23 devnull 
230 9acaad45 2004-10-23 devnull 	/*
231 9acaad45 2004-10-23 devnull 	 * Install handler.
232 9acaad45 2004-10-23 devnull 	 */
233 10f14b04 2005-01-16 devnull 	sigaction(sig->sig, &sa, &osa);
234 10f14b04 2005-01-16 devnull 	return osa.sa_handler == signotify;
235 aa200fe3 2004-10-22 devnull }
236 aa200fe3 2004-10-22 devnull 
237 10f14b04 2005-01-16 devnull int
238 9acaad45 2004-10-23 devnull notifyon(char *msg)
239 aa200fe3 2004-10-22 devnull {
240 10f14b04 2005-01-16 devnull 	return notifyseton(_p9strsig(msg), 1);
241 fd04aace 2003-11-23 devnull }
242 aa200fe3 2004-10-22 devnull 
243 10f14b04 2005-01-16 devnull int
244 9acaad45 2004-10-23 devnull notifyoff(char *msg)
245 aa200fe3 2004-10-22 devnull {
246 10f14b04 2005-01-16 devnull 	return notifyseton(_p9strsig(msg), 0);
247 aa200fe3 2004-10-22 devnull }
248 aa200fe3 2004-10-22 devnull 
249 9acaad45 2004-10-23 devnull /*
250 9acaad45 2004-10-23 devnull  * Initialization follows sigs table.
251 9acaad45 2004-10-23 devnull  */
252 9acaad45 2004-10-23 devnull static void
253 9acaad45 2004-10-23 devnull noteinit(void)
254 aa200fe3 2004-10-22 devnull {
255 aa200fe3 2004-10-22 devnull 	int i;
256 9acaad45 2004-10-23 devnull 	Sig *sig;
257 aa200fe3 2004-10-22 devnull 
258 9acaad45 2004-10-23 devnull 	for(i=0; i<nelem(sigs); i++){
259 9acaad45 2004-10-23 devnull 		sig = &sigs[i];
260 9acaad45 2004-10-23 devnull 		/*
261 9acaad45 2004-10-23 devnull 		 * If someone has already installed a handler,
262 9acaad45 2004-10-23 devnull 		 * It's probably some ld preload nonsense,
263 9acaad45 2004-10-23 devnull 		 * like pct (a SIGVTALRM-based profiler).
264 5f8fa947 2004-12-26 devnull 		 * Or maybe someone has already called notifyon/notifyoff.
265 9acaad45 2004-10-23 devnull 		 * Leave it alone.
266 9acaad45 2004-10-23 devnull 		 */
267 9acaad45 2004-10-23 devnull 		if(handler(sig->sig) != SIG_DFL)
268 9acaad45 2004-10-23 devnull 			continue;
269 f3ecd8ae 2005-02-08 devnull 		notifyseton(sig->sig, 1);
270 9acaad45 2004-10-23 devnull 	}
271 aa200fe3 2004-10-22 devnull }
272 aa200fe3 2004-10-22 devnull