1 #include <u.h>
2 #include <sys/time.h>
3 #include <sys/resource.h>
4 #include "threadimpl.h"
5 
6 #undef waitpid
7 #undef pipe
8 #undef wait
9 
10 static int sigpid;
11 static int threadpassfd;
12 static int gotsigchld;
13 
14 static void
15 child(void)
16 {
17 	int status, pid;
18 	struct rlimit rl;
19 
20 	notedisable("sys: child");
21 	pid = waitpid(sigpid, &status, 0);
22 	if(pid < 0){
23 		fprint(2, "%s: wait: %r\n", argv0);
24 		_exit(97);
25 	}
26 	if(WIFEXITED(status))
27 		 _exit(WEXITSTATUS(status));
28 	if(WIFSIGNALED(status)){
29 		/*
30 		 * Make sure we don't scribble over the nice
31 		 * core file that our child just wrote out.
32 		 */
33 		rl.rlim_cur = 0;
34 		rl.rlim_max = 0;
35 		setrlimit(RLIMIT_CORE, &rl);
36 
37 		signal(WTERMSIG(status), SIG_DFL);
38 		raise(WTERMSIG(status));
39 		_exit(98);	/* not reached */
40 	}
41 	if(WIFSTOPPED(status)){
42 		fprint(2, "%s: wait pid %d stopped\n", argv0, pid);
43 		return;
44 	}
45 #ifdef WIFCONTINUED
46 	if(WIFCONTINUED(status)){
47 		fprint(2, "%s: wait pid %d continued\n", argv0, pid);
48 		return;
49 	}
50 #endif
51 	fprint(2, "%s: wait pid %d status 0x%ux\n", argv0, pid, status);
52 	_exit(99);
53 }
54 
55 static void
56 sigpass(int sig)
57 {
58 	if(sigpid == 1){
59 		gotsigchld = 1;
60 		return;
61 	}
62 
63 	if(sig == SIGCHLD)
64 		child();
65 	else
66 		kill(sigpid, sig);
67 }
68 
69 static int sigs[] = 
70 {
71 	SIGHUP, SIGINT, SIGQUIT, SIGILL,
72 	SIGTRAP, SIGABRT, SIGBUS, SIGFPE,
73 	SIGUSR1, SIGSEGV, SIGUSR2, SIGPIPE,
74 	SIGALRM, SIGTERM, SIGCHLD, SIGSTOP,
75 	SIGTSTP, SIGTTIN, SIGTTOU, SIGURG, 
76 	SIGXCPU, SIGXFSZ, SIGVTALRM, SIGPROF,
77 	SIGWINCH, SIGIO, 
78 #ifdef SIGEMT
79 	SIGEMT,
80 #endif
81 #ifdef SIGPWR
82 	SIGPWR, 
83 #endif
84 #ifdef SIGINFO
85 	SIGINFO,
86 #endif
87 	SIGSYS
88 };
89 
90 void
91 _threadsetupdaemonize(void)
92 {
93 	int i, n, pid;
94 	int p[2];
95 	char buf[20];
96 
97 	sigpid = 1;
98 
99 	if(pipe(p) < 0)
100 		sysfatal("passer pipe: %r");
101 
102 	/* hide these somewhere they won't cause harm */
103 	/* can't go too high: NetBSD max is 64, for example */
104 	if(dup(p[0], 28) < 0 || dup(p[1], 29) < 0)
105 		sysfatal("passer pipe dup: %r");
106 	close(p[0]);
107 	close(p[1]);
108 	p[0] = 28;
109 	p[1] = 29;
110 
111 	/* close on exec */
112 	if(fcntl(p[0], F_SETFD, 1) < 0 || fcntl(p[1], F_SETFD, 1) < 0)
113 		sysfatal("passer pipe pipe fcntl: %r");
114 
115 	noteenable("sys: child");
116 	signal(SIGCHLD, sigpass);
117 	switch(pid = fork()){
118 	case -1:
119 		sysfatal("passer fork: %r");
120 	default:
121 		close(p[1]);
122 		break;
123 	case 0:
124 		notedisable("sys: child");
125 		signal(SIGCHLD, SIG_DFL);
126 	/*	rfork(RFNOTEG); */
127 		close(p[0]);
128 		threadpassfd = p[1];
129 		return;
130 	}
131 
132 	sigpid = pid;
133 	if(gotsigchld)
134 		sigpass(SIGCHLD);
135 
136 	for(i=0; i<nelem(sigs); i++){
137 		struct sigaction sa;
138 
139 		memset(&sa, 0, sizeof sa);
140 		sa.sa_handler = sigpass;
141 		sa.sa_flags |= SA_RESTART;
142 		sigaction(sigs[i], &sa, nil);
143 	}
144 
145 	for(;;){
146 		n = read(p[0], buf, sizeof buf-1);
147 		if(n == 0){	/* program exited */
148 			child();
149 		}
150 		if(n > 0)
151 			break;
152 		print("passer read: %r\n");
153 	}
154 	buf[n] = 0;
155 	_exit(atoi(buf));
156 }
157 
158 void
159 _threaddaemonize(void)
160 {
161 	if(threadpassfd >= 0){
162 		write(threadpassfd, "0", 1);
163 		close(threadpassfd);
164 		threadpassfd = -1;
165 	}
166 }