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.
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.
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.
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>
27 fd04aace 2003-11-23 devnull extern char *_p9sigstr(int, char*);
28 9acaad45 2004-10-23 devnull extern int _p9strsig(char*);
30 9acaad45 2004-10-23 devnull typedef struct Sig Sig;
31 9acaad45 2004-10-23 devnull struct Sig
33 9acaad45 2004-10-23 devnull int sig; /* signal number */
34 9acaad45 2004-10-23 devnull int restart; /* do we restart the system call after this signal is handled? */
35 9acaad45 2004-10-23 devnull int enabled; /* is this signal enabled (not masked)? */
36 9acaad45 2004-10-23 devnull int notified; /* do we call the notify function for this signal? */
40 10f14b04 2005-01-16 devnull * Bug. It is profoundly anti-social to play with the masks like this.
41 10f14b04 2005-01-16 devnull * For example, even though we don't want to see SIGTSTP, others do.
42 10f14b04 2005-01-16 devnull * Running bash inside a 9term that has disabled SIGTSTP makes ^Z not work.
43 10f14b04 2005-01-16 devnull * Instead we need to leave the signals enabled but notifyoff them.
46 9acaad45 2004-10-23 devnull /* initial settings; for current status, ask the kernel */
47 9acaad45 2004-10-23 devnull static Sig sigs[] = {
48 9acaad45 2004-10-23 devnull SIGHUP, 0, 1, 1,
49 9acaad45 2004-10-23 devnull SIGINT, 0, 1, 1,
50 9acaad45 2004-10-23 devnull SIGQUIT, 0, 1, 1,
51 9acaad45 2004-10-23 devnull SIGILL, 0, 1, 1,
52 9acaad45 2004-10-23 devnull SIGTRAP, 0, 1, 1,
53 9acaad45 2004-10-23 devnull /* SIGABRT, 0, 1, 1, */
54 d2c4ee9e 2003-11-24 devnull #ifdef SIGEMT
55 9acaad45 2004-10-23 devnull SIGEMT, 0, 1, 1,
57 9acaad45 2004-10-23 devnull SIGFPE, 0, 1, 1,
58 9acaad45 2004-10-23 devnull SIGBUS, 0, 1, 1,
59 9acaad45 2004-10-23 devnull /* SIGSEGV, 0, 1, 1, */
60 9acaad45 2004-10-23 devnull SIGCHLD, 1, 0, 1,
61 9acaad45 2004-10-23 devnull SIGSYS, 0, 1, 1,
62 9acaad45 2004-10-23 devnull SIGPIPE, 0, 0, 1,
63 9acaad45 2004-10-23 devnull SIGALRM, 0, 1, 1,
64 9acaad45 2004-10-23 devnull SIGTERM, 0, 1, 1,
65 9acaad45 2004-10-23 devnull SIGTSTP, 1, 0, 1,
66 9acaad45 2004-10-23 devnull SIGTTIN, 1, 0, 1,
67 9acaad45 2004-10-23 devnull SIGTTOU, 1, 0, 1,
68 9acaad45 2004-10-23 devnull SIGXCPU, 0, 1, 1,
69 9acaad45 2004-10-23 devnull SIGXFSZ, 0, 1, 1,
70 9acaad45 2004-10-23 devnull SIGVTALRM, 0, 1, 1,
71 9acaad45 2004-10-23 devnull SIGUSR1, 0, 1, 1,
72 9acaad45 2004-10-23 devnull SIGUSR2, 0, 1, 1,
73 9acaad45 2004-10-23 devnull SIGWINCH, 1, 0, 1,
74 d2c4ee9e 2003-11-24 devnull #ifdef SIGINFO
75 9acaad45 2004-10-23 devnull SIGINFO, 1, 1, 1,
79 9acaad45 2004-10-23 devnull static Sig*
80 9acaad45 2004-10-23 devnull findsig(int s)
84 9acaad45 2004-10-23 devnull for(i=0; i<nelem(sigs); i++)
85 9acaad45 2004-10-23 devnull if(sigs[i].sig == s)
86 9acaad45 2004-10-23 devnull return &sigs[i];
87 9acaad45 2004-10-23 devnull return nil;
91 9acaad45 2004-10-23 devnull * The thread library initializes _notejmpbuf to its own
92 9acaad45 2004-10-23 devnull * routine which provides a per-pthread jump buffer.
93 9acaad45 2004-10-23 devnull * If we're not using the thread library, we assume we are
94 9acaad45 2004-10-23 devnull * single-threaded.
96 05d8c6df 2004-09-23 devnull typedef struct Jmp Jmp;
97 05d8c6df 2004-09-23 devnull struct Jmp
99 05d8c6df 2004-09-23 devnull p9jmp_buf b;
102 05d8c6df 2004-09-23 devnull static Jmp onejmp;
104 05d8c6df 2004-09-23 devnull static Jmp*
105 05d8c6df 2004-09-23 devnull getonejmp(void)
107 05d8c6df 2004-09-23 devnull return &onejmp;
110 05d8c6df 2004-09-23 devnull Jmp *(*_notejmpbuf)(void) = getonejmp;
111 9acaad45 2004-10-23 devnull static void noteinit(void);
114 9acaad45 2004-10-23 devnull * Actual signal handler.
117 9acaad45 2004-10-23 devnull static void (*notifyf)(void*, char*); /* Plan 9 handler */
119 aa200fe3 2004-10-22 devnull static void
120 9acaad45 2004-10-23 devnull signotify(int sig)
122 fd04aace 2003-11-23 devnull char tmp[64];
125 05d8c6df 2004-09-23 devnull j = (*_notejmpbuf)();
126 9acaad45 2004-10-23 devnull switch(p9setjmp(j->b)){
128 9acaad45 2004-10-23 devnull if(notifyf)
129 9acaad45 2004-10-23 devnull (*notifyf)(nil, _p9sigstr(sig, tmp));
130 9acaad45 2004-10-23 devnull /* fall through */
131 9acaad45 2004-10-23 devnull case 1: /* noted(NDFLT) */
132 9acaad45 2004-10-23 devnull if(0)print("DEFAULT %d\n", sig);
133 9acaad45 2004-10-23 devnull signal(sig, SIG_DFL);
134 9acaad45 2004-10-23 devnull raise(sig);
135 9acaad45 2004-10-23 devnull _exit(1);
136 9acaad45 2004-10-23 devnull case 2: /* noted(NCONT) */
137 05d8c6df 2004-09-23 devnull if(0)print("HANDLED %d\n", sig);
142 9acaad45 2004-10-23 devnull static void
143 9acaad45 2004-10-23 devnull signonotify(int sig)
145 9acaad45 2004-10-23 devnull USED(sig);
149 05d8c6df 2004-09-23 devnull noted(int v)
151 05d8c6df 2004-09-23 devnull p9longjmp((*_notejmpbuf)()->b, v==NCONT ? 2 : 1);
152 05d8c6df 2004-09-23 devnull abort();
153 05d8c6df 2004-09-23 devnull return 0;
157 9acaad45 2004-10-23 devnull notify(void (*f)(void*, char*))
159 9acaad45 2004-10-23 devnull static int init;
161 9acaad45 2004-10-23 devnull notifyf = f;
162 9acaad45 2004-10-23 devnull if(!init){
163 9acaad45 2004-10-23 devnull init = 1;
164 9acaad45 2004-10-23 devnull noteinit();
166 9acaad45 2004-10-23 devnull return 0;
170 9acaad45 2004-10-23 devnull * Nonsense about enabling and disabling signals.
172 5f8fa947 2004-12-26 devnull typedef void Sighandler(int);
173 5f8fa947 2004-12-26 devnull static Sighandler*
174 9acaad45 2004-10-23 devnull handler(int s)
176 9acaad45 2004-10-23 devnull struct sigaction sa;
178 9acaad45 2004-10-23 devnull sigaction(s, nil, &sa);
179 9acaad45 2004-10-23 devnull return sa.sa_handler;
182 10f14b04 2005-01-16 devnull static int
183 5f8fa947 2004-12-26 devnull notesetenable(int sig, int enabled)
185 10f14b04 2005-01-16 devnull sigset_t mask, omask;
187 9acaad45 2004-10-23 devnull if(sig == 0)
188 10f14b04 2005-01-16 devnull return -1;
190 9acaad45 2004-10-23 devnull sigemptyset(&mask);
191 9acaad45 2004-10-23 devnull sigaddset(&mask, sig);
192 10f14b04 2005-01-16 devnull sigprocmask(enabled ? SIG_UNBLOCK : SIG_BLOCK, &mask, &omask);
193 10f14b04 2005-01-16 devnull return !sigismember(&omask, sig);
197 5f8fa947 2004-12-26 devnull noteenable(char *msg)
199 10f14b04 2005-01-16 devnull return notesetenable(_p9strsig(msg), 1);
203 5f8fa947 2004-12-26 devnull notedisable(char *msg)
205 10f14b04 2005-01-16 devnull return notesetenable(_p9strsig(msg), 0);
208 10f14b04 2005-01-16 devnull static int
209 9acaad45 2004-10-23 devnull notifyseton(int s, int on)
211 9acaad45 2004-10-23 devnull Sig *sig;
212 10f14b04 2005-01-16 devnull struct sigaction sa, osa;
214 9acaad45 2004-10-23 devnull sig = findsig(s);
215 9acaad45 2004-10-23 devnull if(sig == nil)
216 10f14b04 2005-01-16 devnull return -1;
217 669250d1 2003-12-03 devnull memset(&sa, 0, sizeof sa);
218 9acaad45 2004-10-23 devnull sa.sa_handler = on ? signotify : signonotify;
219 9acaad45 2004-10-23 devnull if(sig->restart)
220 9acaad45 2004-10-23 devnull sa.sa_flags |= SA_RESTART;
223 9acaad45 2004-10-23 devnull * We can't allow signals within signals because there's
224 9acaad45 2004-10-23 devnull * only one jump buffer.
226 aa200fe3 2004-10-22 devnull sigfillset(&sa.sa_mask);
229 9acaad45 2004-10-23 devnull * Install handler.
231 10f14b04 2005-01-16 devnull sigaction(sig->sig, &sa, &osa);
232 10f14b04 2005-01-16 devnull return osa.sa_handler == signotify;
236 9acaad45 2004-10-23 devnull notifyon(char *msg)
238 10f14b04 2005-01-16 devnull return notifyseton(_p9strsig(msg), 1);
242 9acaad45 2004-10-23 devnull notifyoff(char *msg)
244 10f14b04 2005-01-16 devnull return notifyseton(_p9strsig(msg), 0);
248 9acaad45 2004-10-23 devnull * Initialization follows sigs table.
250 9acaad45 2004-10-23 devnull static void
251 9acaad45 2004-10-23 devnull noteinit(void)
254 9acaad45 2004-10-23 devnull Sig *sig;
256 9acaad45 2004-10-23 devnull for(i=0; i<nelem(sigs); i++){
257 9acaad45 2004-10-23 devnull sig = &sigs[i];
259 9acaad45 2004-10-23 devnull * If someone has already installed a handler,
260 9acaad45 2004-10-23 devnull * It's probably some ld preload nonsense,
261 9acaad45 2004-10-23 devnull * like pct (a SIGVTALRM-based profiler).
262 5f8fa947 2004-12-26 devnull * Or maybe someone has already called notifyon/notifyoff.
263 9acaad45 2004-10-23 devnull * Leave it alone.
265 9acaad45 2004-10-23 devnull if(handler(sig->sig) != SIG_DFL)
266 9acaad45 2004-10-23 devnull continue;
268 9acaad45 2004-10-23 devnull * Should we only disable and not enable signals?
269 9acaad45 2004-10-23 devnull * (I.e. if parent has disabled for us, should we still enable?)
270 9acaad45 2004-10-23 devnull * Right now we always initialize to the state we want.
272 5f8fa947 2004-12-26 devnull notesetenable(sig->sig, sig->enabled);
273 9acaad45 2004-10-23 devnull notifyseton(sig->sig, sig->notified);
