1 #include <u.h>
2 #include <signal.h>
3 #define NOPLAN9DEFINES
4 #include <libc.h>
5 
6 extern char *_p9sigstr(int, char*);
7 
8 static struct {
9 	int sig;
10 	int restart;
11 	int dumb;
12 } sigs[] = {
13 	SIGHUP, 0, 0,
14 	SIGINT, 0, 0,
15 	SIGQUIT, 0, 0,
16 	SIGILL, 0, 0,
17 	SIGTRAP, 0, 0,
18 /*	SIGABRT,	*/
19 #ifdef SIGEMT
20 	SIGEMT, 0, 0,
21 #endif
22 	SIGFPE, 0, 0,
23 	SIGBUS, 0, 0,
24 /*	SIGSEGV,	*/
25 	SIGCHLD, 1, 1,
26 	SIGSYS, 0, 0,
27 	SIGPIPE, 0, 1,
28 	SIGALRM, 0, 0,
29 	SIGTERM, 0, 0,
30 	SIGTSTP, 1, 1,
31 	SIGTTIN, 1, 1,
32 	SIGTTOU, 1, 1,
33 	SIGXCPU, 0, 0,
34 	SIGXFSZ, 0, 0,
35 	SIGVTALRM, 0, 0,
36 	SIGUSR1, 0, 0,
37 	SIGUSR2, 0, 0,
38 	SIGWINCH, 1, 1,
39 #ifdef SIGINFO
40 	SIGINFO, 0, 0,
41 #endif
42 };
43 
44 typedef struct Jmp Jmp;
45 struct Jmp
46 {
47 	p9jmp_buf b;
48 };
49 
50 static Jmp onejmp;
51 
52 static Jmp*
53 getonejmp(void)
54 {
55 	return &onejmp;
56 }
57 
58 Jmp *(*_notejmpbuf)(void) = getonejmp;
59 static void (*notifyf)(void*, char*);
60 static int alldumb;
61 
62 static void
63 nop(int sig)
64 {
65 	USED(sig);
66 }
67 
68 static void
69 notifysigf(int sig)
70 {
71 	int v;
72 	char tmp[64];
73 	Jmp *j;
74 
75 	j = (*_notejmpbuf)();
76 	v = p9setjmp(j->b);
77 	if(v == 0 && notifyf)
78 		(*notifyf)(nil, _p9sigstr(sig, tmp));
79 	else if(v == 2){
80 		if(0)print("HANDLED %d\n", sig);
81 		return;
82 	}
83 	if(0)print("DEFAULT %d\n", sig);
84 	signal(sig, SIG_DFL);
85 	raise(sig);
86 }
87 
88 int
89 noted(int v)
90 {
91 	p9longjmp((*_notejmpbuf)()->b, v==NCONT ? 2 : 1);
92 	abort();
93 	return 0;
94 }
95 
96 static void
97 handlesig(int s, int r, int skip)
98 {
99 	struct sigaction sa, osa;
100 
101 	/*
102 	 * If someone has already installed a handler,
103 	 * It's probably some ld preload nonsense,
104 	 * like pct (a SIGVTALRM-based profiler).
105 	 * Leave it alone.
106 	 */
107 	sigaction(s, nil, &osa);
108 	if(osa.sa_handler != SIG_DFL && osa.sa_handler != notifysigf && osa.sa_handler != nop)
109 		return;
110 
111 	memset(&sa, 0, sizeof sa);
112 	if(skip)
113 		sa.sa_handler = nop;
114 	else if(notifyf == 0)
115 		sa.sa_handler = SIG_DFL;
116 	else
117 		sa.sa_handler = notifysigf;
118 
119 	/*
120 	 * We assume that one jump buffer per thread
121 	 * is okay, which means that we can't deal with 
122 	 * signal handlers called during signal handlers.
123 	 */
124 	sigfillset(&sa.sa_mask);
125 	if(r)
126 		sa.sa_flags |= SA_RESTART;
127 	else
128 		sa.sa_flags &= ~SA_RESTART;
129 	sigaction(s, &sa, nil);
130 }
131 
132 int
133 notify(void (*f)(void*, char*))
134 {
135 	int i;
136 
137 	notifyf = f;
138 	for(i=0; i<nelem(sigs); i++)
139 		handlesig(sigs[i].sig, sigs[i].restart, sigs[i].dumb && !alldumb);
140 	return 0;
141 }
142 
143 void
144 notifyall(int all)
145 {
146 	int i;
147 
148 	alldumb = all;
149 	for(i=0; i<nelem(sigs); i++)
150 		if(sigs[i].dumb)
151 			handlesig(sigs[i].sig, sigs[i].restart, !all);
152 }
153 
154 void
155 notifyatsig(int sig, int use)
156 {
157 	int i;
158 
159 	for(i=0; i<nelem(sigs); i++)
160 		if(sigs[i].sig == sig)
161 			handlesig(sigs[i].sig, sigs[i].restart, 0);
162 }
163