1 175b8a53 2004-04-21 devnull #include <u.h>
 2 06c4fd06 2004-04-21 devnull #include <sys/wait.h>
 3 06c4fd06 2004-04-21 devnull #include <signal.h>
 4 175b8a53 2004-04-21 devnull #include <libc.h>
 5 175b8a53 2004-04-21 devnull #undef rfork
 6 fd04aace 2003-11-23 devnull 
 7 fd04aace 2003-11-23 devnull int
 8 fd04aace 2003-11-23 devnull p9rfork(int flags)
 9 fd04aace 2003-11-23 devnull {
10 06c4fd06 2004-04-21 devnull 	int pid, status;
11 06c4fd06 2004-04-21 devnull 	int p[2];
12 06c4fd06 2004-04-21 devnull 	int n;
13 06c4fd06 2004-04-21 devnull 	char buf[128], *q;
14 1c8efa18 2003-12-04 devnull 
15 1c8efa18 2003-12-04 devnull 	if((flags&(RFPROC|RFFDG|RFMEM)) == (RFPROC|RFFDG)){
16 1c8efa18 2003-12-04 devnull 		/* check other flags before we commit */
17 1c8efa18 2003-12-04 devnull 		flags &= ~(RFPROC|RFFDG);
18 06c4fd06 2004-04-21 devnull 		n = (flags & ~(RFNOTEG|RFNAMEG|RFNOWAIT));
19 06c4fd06 2004-04-21 devnull 		if(n){
20 06c4fd06 2004-04-21 devnull 			werrstr("unknown flags %08ux in rfork", n);
21 1c8efa18 2003-12-04 devnull 			return -1;
22 1c8efa18 2003-12-04 devnull 		}
23 06c4fd06 2004-04-21 devnull 		if(flags&RFNOWAIT){
24 06c4fd06 2004-04-21 devnull 			if(pipe(p) < 0)
25 06c4fd06 2004-04-21 devnull 				return -1;
26 06c4fd06 2004-04-21 devnull 		}
27 1c8efa18 2003-12-04 devnull 		pid = fork();
28 06c4fd06 2004-04-21 devnull 		if(pid == -1)
29 06c4fd06 2004-04-21 devnull 			return -1;
30 06c4fd06 2004-04-21 devnull 		if(flags&RFNOWAIT){
31 06c4fd06 2004-04-21 devnull 			flags &= ~RFNOWAIT;
32 06c4fd06 2004-04-21 devnull 			if(pid){
33 06c4fd06 2004-04-21 devnull 				/*
34 06c4fd06 2004-04-21 devnull 				 * Parent - wait for child to fork wait-free child.
35 06c4fd06 2004-04-21 devnull 				 * Then read pid from pipe.  Assume pipe buffer can absorb the write.
36 06c4fd06 2004-04-21 devnull 				 */
37 06c4fd06 2004-04-21 devnull 				close(p[1]);
38 06c4fd06 2004-04-21 devnull 				wait4(pid, &status, 0, 0);
39 06c4fd06 2004-04-21 devnull 				n = readn(p[0], buf, sizeof buf-1);
40 06c4fd06 2004-04-21 devnull 				close(p[0]);
41 06c4fd06 2004-04-21 devnull 				if(!WIFEXITED(status) || WEXITSTATUS(status)!=0 || n <= 0){
42 06c4fd06 2004-04-21 devnull 					werrstr("pipe dance failed in rfork");
43 06c4fd06 2004-04-21 devnull 					return -1;
44 06c4fd06 2004-04-21 devnull 				}
45 06c4fd06 2004-04-21 devnull 				buf[n] = 0;
46 06c4fd06 2004-04-21 devnull 				n = strtol(buf, &q, 0);
47 06c4fd06 2004-04-21 devnull 				if(*q != 0){
48 06c4fd06 2004-04-21 devnull 					werrstr("%s", q);
49 06c4fd06 2004-04-21 devnull 					return -1;
50 06c4fd06 2004-04-21 devnull 				}
51 06c4fd06 2004-04-21 devnull 				pid = n;
52 06c4fd06 2004-04-21 devnull 			}else{
53 06c4fd06 2004-04-21 devnull 				/*
54 06c4fd06 2004-04-21 devnull 				 * Child - fork a new child whose wait message can't 
55 06c4fd06 2004-04-21 devnull 				 * get back to the parent because we're going to exit!
56 06c4fd06 2004-04-21 devnull 				 */
57 06c4fd06 2004-04-21 devnull 				signal(SIGCHLD, SIG_IGN);
58 06c4fd06 2004-04-21 devnull 				close(p[0]);
59 06c4fd06 2004-04-21 devnull 				pid = fork();
60 06c4fd06 2004-04-21 devnull 				if(pid){
61 06c4fd06 2004-04-21 devnull 					/* Child parent - send status over pipe and exit. */
62 06c4fd06 2004-04-21 devnull 					if(pid > 0)
63 06c4fd06 2004-04-21 devnull 						fprint(p[1], "%d", pid);
64 06c4fd06 2004-04-21 devnull 					else
65 06c4fd06 2004-04-21 devnull 						fprint(p[1], " %r");
66 06c4fd06 2004-04-21 devnull 					close(p[1]);
67 06c4fd06 2004-04-21 devnull 					_exit(0);
68 06c4fd06 2004-04-21 devnull 				}else{
69 06c4fd06 2004-04-21 devnull 					/* Child child - close pipe. */
70 06c4fd06 2004-04-21 devnull 					close(p[1]);
71 06c4fd06 2004-04-21 devnull 				}
72 06c4fd06 2004-04-21 devnull 			}
73 06c4fd06 2004-04-21 devnull 		}
74 1c8efa18 2003-12-04 devnull 		if(pid != 0)
75 1c8efa18 2003-12-04 devnull 			return pid;
76 1c8efa18 2003-12-04 devnull 	}
77 fd04aace 2003-11-23 devnull 	if(flags&RFPROC){
78 32f69c36 2003-12-11 devnull 		werrstr("cannot use rfork for shared memory -- use ffork");
79 fd04aace 2003-11-23 devnull 		return -1;
80 fd04aace 2003-11-23 devnull 	}
81 32f69c36 2003-12-11 devnull 	if(flags&RFNAMEG){
82 32f69c36 2003-12-11 devnull 		/* XXX set $NAMESPACE to a new directory */
83 32f69c36 2003-12-11 devnull 		flags &= ~RFNAMEG;
84 32f69c36 2003-12-11 devnull 	}
85 fd04aace 2003-11-23 devnull 	if(flags&RFNOTEG){
86 1c253ceb 2003-11-23 devnull 		setpgid(0, getpid());
87 fd04aace 2003-11-23 devnull 		flags &= ~RFNOTEG;
88 fd04aace 2003-11-23 devnull 	}
89 06c4fd06 2004-04-21 devnull 	if(flags&RFNOWAIT){
90 06c4fd06 2004-04-21 devnull 		werrstr("cannot use RFNOWAIT without RFPROC");
91 06c4fd06 2004-04-21 devnull 		return -1;
92 06c4fd06 2004-04-21 devnull 	}
93 fd04aace 2003-11-23 devnull 	if(flags){
94 fd04aace 2003-11-23 devnull 		werrstr("unknown flags %08ux in rfork", flags);
95 fd04aace 2003-11-23 devnull 		return -1;
96 fd04aace 2003-11-23 devnull 	}
97 fd04aace 2003-11-23 devnull 	return 0;
98 fd04aace 2003-11-23 devnull }