1 #include "threadimpl.h"
2 
3 #undef pipe
4 #undef wait
5 
6 static int sigpid;
7 static int threadpassfd;
8 
9 static void
10 child(void)
11 {
12 	int status, pid;
13 	pid = wait(&status);
14 	if(pid < 0)
15 		fprint(2, "wait: %r\n");
16 	else if(WIFEXITED(status))
17 		 _exit(WEXITSTATUS(status));
18 print("pid %d if %d %d\n", pid, WIFEXITED(status), WEXITSTATUS(status));
19 	_exit(97);
20 }
21 
22 static void
23 sigpass(int sig)
24 {
25 	if(sig == SIGCHLD)
26 		child();
27 	else
28 		kill(sigpid, sig);
29 }
30 
31 void
32 _threadsetupdaemonize(void)
33 {
34 	int i, n, pid;
35 	int p[2];
36 	char buf[20];
37 
38 	sigpid = 1;
39 
40 	threadlinklibrary();
41 
42 	if(pipe(p) < 0)
43 		sysfatal("passer pipe: %r");
44 
45 	/* hide these somewhere they won't cause harm */
46 	if(dup(p[0], 98) < 0 || dup(p[1], 99) < 0)
47 		sysfatal("passer pipe dup: %r");
48 	close(p[0]);
49 	close(p[1]);
50 	p[0] = 98;
51 	p[1] = 99;
52 
53 	/* close on exec */
54 	if(fcntl(p[0], F_SETFD, 1) < 0 || fcntl(p[1], F_SETFD, 1) < 0)
55 		sysfatal("passer pipe pipe fcntl: %r");
56 
57 	signal(SIGCHLD, sigpass);
58 	switch(pid = fork()){
59 	case -1:
60 		sysfatal("passer fork: %r");
61 	default:
62 		close(p[1]);
63 		break;
64 	case 0:
65 		signal(SIGCHLD, SIG_DFL);
66 		rfork(RFNOTEG);
67 		close(p[0]);
68 		threadpassfd = p[1];
69 		return;
70 	}
71 
72 	sigpid = pid;
73 	for(i=0; i<NSIG; i++){
74 		struct sigaction sa;
75 
76 		memset(&sa, 0, sizeof sa);
77 		sa.sa_handler = sigpass;
78 		sa.sa_flags |= SA_RESTART;
79 		sigaction(i, &sa, nil);
80 	}
81 
82 	for(;;){
83 		n = read(p[0], buf, sizeof buf-1);
84 		if(n == 0)	/* program exited */
85 			child();
86 		if(n > 0)
87 			break;
88 		print("passer read: %r\n");
89 	}
90 	buf[n] = 0;
91 	_exit(atoi(buf));
92 }
93 
94 void
95 threaddaemonize(void)
96 {
97 	if(threadpassfd >= 0){
98 		write(threadpassfd, "0", 1);
99 		close(threadpassfd);
100 		threadpassfd = -1;
101 	}
102 }