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 32116738 2004-10-22 devnull static void
  8 32116738 2004-10-22 devnull nop(int x)
  9 32116738 2004-10-22 devnull {
 10 32116738 2004-10-22 devnull 	USED(x);
 11 32116738 2004-10-22 devnull }
 12 32116738 2004-10-22 devnull 
 13 fd04aace 2003-11-23 devnull int
 14 fd04aace 2003-11-23 devnull p9rfork(int flags)
 15 fd04aace 2003-11-23 devnull {
 16 06c4fd06 2004-04-21 devnull 	int pid, status;
 17 06c4fd06 2004-04-21 devnull 	int p[2];
 18 22ba8d1f 2006-02-12 devnull 	int n;
 19 06c4fd06 2004-04-21 devnull 	char buf[128], *q;
 20 e4d83222 2006-02-11 devnull 	extern char **environ;
 21 33348254 2011-05-01 rsc 	struct sigaction oldchld;
 22 1c8efa18 2003-12-04 devnull 
 23 33348254 2011-05-01 rsc 	memset(&oldchld, 0, sizeof oldchld);
 24 33348254 2011-05-01 rsc 
 25 1c8efa18 2003-12-04 devnull 	if((flags&(RFPROC|RFFDG|RFMEM)) == (RFPROC|RFFDG)){
 26 1c8efa18 2003-12-04 devnull 		/* check other flags before we commit */
 27 e4d83222 2006-02-11 devnull 		flags &= ~(RFPROC|RFFDG|RFENVG);
 28 e4d83222 2006-02-11 devnull 		n = (flags & ~(RFNOTEG|RFNAMEG|RFNOWAIT|RFCENVG));
 29 06c4fd06 2004-04-21 devnull 		if(n){
 30 06c4fd06 2004-04-21 devnull 			werrstr("unknown flags %08ux in rfork", n);
 31 1c8efa18 2003-12-04 devnull 			return -1;
 32 1c8efa18 2003-12-04 devnull 		}
 33 06c4fd06 2004-04-21 devnull 		if(flags&RFNOWAIT){
 34 33348254 2011-05-01 rsc 			sigaction(SIGCHLD, nil, &oldchld);
 35 32116738 2004-10-22 devnull 			signal(SIGCHLD, nop);
 36 06c4fd06 2004-04-21 devnull 			if(pipe(p) < 0)
 37 06c4fd06 2004-04-21 devnull 				return -1;
 38 06c4fd06 2004-04-21 devnull 		}
 39 1c8efa18 2003-12-04 devnull 		pid = fork();
 40 06c4fd06 2004-04-21 devnull 		if(pid == -1)
 41 06c4fd06 2004-04-21 devnull 			return -1;
 42 06c4fd06 2004-04-21 devnull 		if(flags&RFNOWAIT){
 43 06c4fd06 2004-04-21 devnull 			flags &= ~RFNOWAIT;
 44 06c4fd06 2004-04-21 devnull 			if(pid){
 45 06c4fd06 2004-04-21 devnull 				/*
 46 06c4fd06 2004-04-21 devnull 				 * Parent - wait for child to fork wait-free child.
 47 06c4fd06 2004-04-21 devnull 				 * Then read pid from pipe.  Assume pipe buffer can absorb the write.
 48 06c4fd06 2004-04-21 devnull 				 */
 49 06c4fd06 2004-04-21 devnull 				close(p[1]);
 50 32116738 2004-10-22 devnull 				status = 0;
 51 32116738 2004-10-22 devnull 				if(wait4(pid, &status, 0, 0) < 0){
 52 32116738 2004-10-22 devnull 					werrstr("pipe dance - wait4 - %r");
 53 32116738 2004-10-22 devnull 					close(p[0]);
 54 32116738 2004-10-22 devnull 					return -1;
 55 32116738 2004-10-22 devnull 				}
 56 06c4fd06 2004-04-21 devnull 				n = readn(p[0], buf, sizeof buf-1);
 57 06c4fd06 2004-04-21 devnull 				close(p[0]);
 58 06c4fd06 2004-04-21 devnull 				if(!WIFEXITED(status) || WEXITSTATUS(status)!=0 || n <= 0){
 59 32116738 2004-10-22 devnull 					if(!WIFEXITED(status))
 60 32116738 2004-10-22 devnull 						werrstr("pipe dance - !exited 0x%ux", status);
 61 32116738 2004-10-22 devnull 					else if(WEXITSTATUS(status) != 0)
 62 32116738 2004-10-22 devnull 						werrstr("pipe dance - non-zero status 0x%ux", status);
 63 32116738 2004-10-22 devnull 					else if(n < 0)
 64 32116738 2004-10-22 devnull 						werrstr("pipe dance - pipe read error - %r");
 65 32116738 2004-10-22 devnull 					else if(n == 0)
 66 32116738 2004-10-22 devnull 						werrstr("pipe dance - pipe read eof");
 67 32116738 2004-10-22 devnull 					else
 68 32116738 2004-10-22 devnull 						werrstr("pipe dance - unknown failure");
 69 06c4fd06 2004-04-21 devnull 					return -1;
 70 06c4fd06 2004-04-21 devnull 				}
 71 06c4fd06 2004-04-21 devnull 				buf[n] = 0;
 72 32116738 2004-10-22 devnull 				if(buf[0] == 'x'){
 73 32116738 2004-10-22 devnull 					werrstr("%s", buf+2);
 74 06c4fd06 2004-04-21 devnull 					return -1;
 75 06c4fd06 2004-04-21 devnull 				}
 76 32116738 2004-10-22 devnull 				pid = strtol(buf, &q, 0);
 77 06c4fd06 2004-04-21 devnull 			}else{
 78 06c4fd06 2004-04-21 devnull 				/*
 79 fa325e9b 2020-01-10 cross 				 * Child - fork a new child whose wait message can't
 80 06c4fd06 2004-04-21 devnull 				 * get back to the parent because we're going to exit!
 81 06c4fd06 2004-04-21 devnull 				 */
 82 06c4fd06 2004-04-21 devnull 				signal(SIGCHLD, SIG_IGN);
 83 06c4fd06 2004-04-21 devnull 				close(p[0]);
 84 06c4fd06 2004-04-21 devnull 				pid = fork();
 85 06c4fd06 2004-04-21 devnull 				if(pid){
 86 06c4fd06 2004-04-21 devnull 					/* Child parent - send status over pipe and exit. */
 87 06c4fd06 2004-04-21 devnull 					if(pid > 0)
 88 06c4fd06 2004-04-21 devnull 						fprint(p[1], "%d", pid);
 89 06c4fd06 2004-04-21 devnull 					else
 90 32116738 2004-10-22 devnull 						fprint(p[1], "x %r");
 91 06c4fd06 2004-04-21 devnull 					close(p[1]);
 92 06c4fd06 2004-04-21 devnull 					_exit(0);
 93 06c4fd06 2004-04-21 devnull 				}else{
 94 06c4fd06 2004-04-21 devnull 					/* Child child - close pipe. */
 95 06c4fd06 2004-04-21 devnull 					close(p[1]);
 96 06c4fd06 2004-04-21 devnull 				}
 97 06c4fd06 2004-04-21 devnull 			}
 98 33348254 2011-05-01 rsc 			sigaction(SIGCHLD, &oldchld, nil);
 99 06c4fd06 2004-04-21 devnull 		}
100 1c8efa18 2003-12-04 devnull 		if(pid != 0)
101 1c8efa18 2003-12-04 devnull 			return pid;
102 e4d83222 2006-02-11 devnull 		if(flags&RFCENVG)
103 e4d83222 2006-02-11 devnull 			if(environ)
104 e4d83222 2006-02-11 devnull 				*environ = nil;
105 1c8efa18 2003-12-04 devnull 	}
106 fd04aace 2003-11-23 devnull 	if(flags&RFPROC){
107 cd374519 2005-10-29 devnull 		werrstr("cannot use rfork for shared memory -- use libthread");
108 fd04aace 2003-11-23 devnull 		return -1;
109 fd04aace 2003-11-23 devnull 	}
110 32f69c36 2003-12-11 devnull 	if(flags&RFNAMEG){
111 32f69c36 2003-12-11 devnull 		/* XXX set $NAMESPACE to a new directory */
112 32f69c36 2003-12-11 devnull 		flags &= ~RFNAMEG;
113 32f69c36 2003-12-11 devnull 	}
114 fd04aace 2003-11-23 devnull 	if(flags&RFNOTEG){
115 1c253ceb 2003-11-23 devnull 		setpgid(0, getpid());
116 fd04aace 2003-11-23 devnull 		flags &= ~RFNOTEG;
117 fd04aace 2003-11-23 devnull 	}
118 06c4fd06 2004-04-21 devnull 	if(flags&RFNOWAIT){
119 06c4fd06 2004-04-21 devnull 		werrstr("cannot use RFNOWAIT without RFPROC");
120 06c4fd06 2004-04-21 devnull 		return -1;
121 06c4fd06 2004-04-21 devnull 	}
122 fd04aace 2003-11-23 devnull 	if(flags){
123 fd04aace 2003-11-23 devnull 		werrstr("unknown flags %08ux in rfork", flags);
124 fd04aace 2003-11-23 devnull 		return -1;
125 fd04aace 2003-11-23 devnull 	}
126 fd04aace 2003-11-23 devnull 	return 0;
127 fd04aace 2003-11-23 devnull }