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 #include "9proc.h"
  6 175b8a53 2004-04-21 devnull #undef rfork
  7 fd04aace 2003-11-23 devnull 
  8 fd04aace 2003-11-23 devnull int
  9 fd04aace 2003-11-23 devnull p9rfork(int flags)
 10 fd04aace 2003-11-23 devnull {
 11 06c4fd06 2004-04-21 devnull 	int pid, status;
 12 06c4fd06 2004-04-21 devnull 	int p[2];
 13 06c4fd06 2004-04-21 devnull 	int n;
 14 06c4fd06 2004-04-21 devnull 	char buf[128], *q;
 15 1c8efa18 2003-12-04 devnull 
 16 06c4fd06 2004-04-21 devnull 	_p9uproc(0);
 17 1c8efa18 2003-12-04 devnull 	if((flags&(RFPROC|RFFDG|RFMEM)) == (RFPROC|RFFDG)){
 18 1c8efa18 2003-12-04 devnull 		/* check other flags before we commit */
 19 1c8efa18 2003-12-04 devnull 		flags &= ~(RFPROC|RFFDG);
 20 06c4fd06 2004-04-21 devnull 		n = (flags & ~(RFNOTEG|RFNAMEG|RFNOWAIT));
 21 06c4fd06 2004-04-21 devnull 		if(n){
 22 06c4fd06 2004-04-21 devnull 			werrstr("unknown flags %08ux in rfork", n);
 23 1c8efa18 2003-12-04 devnull 			return -1;
 24 1c8efa18 2003-12-04 devnull 		}
 25 06c4fd06 2004-04-21 devnull 		if(flags&RFNOWAIT){
 26 06c4fd06 2004-04-21 devnull 			if(pipe(p) < 0)
 27 06c4fd06 2004-04-21 devnull 				return -1;
 28 06c4fd06 2004-04-21 devnull 		}
 29 1c8efa18 2003-12-04 devnull 		pid = fork();
 30 06c4fd06 2004-04-21 devnull 		if(pid == -1)
 31 06c4fd06 2004-04-21 devnull 			return -1;
 32 06c4fd06 2004-04-21 devnull 		if(flags&RFNOWAIT){
 33 06c4fd06 2004-04-21 devnull 			flags &= ~RFNOWAIT;
 34 06c4fd06 2004-04-21 devnull 			if(pid){
 35 06c4fd06 2004-04-21 devnull 				/*
 36 06c4fd06 2004-04-21 devnull 				 * Parent - wait for child to fork wait-free child.
 37 06c4fd06 2004-04-21 devnull 				 * Then read pid from pipe.  Assume pipe buffer can absorb the write.
 38 06c4fd06 2004-04-21 devnull 				 */
 39 06c4fd06 2004-04-21 devnull 				close(p[1]);
 40 06c4fd06 2004-04-21 devnull 				wait4(pid, &status, 0, 0);
 41 06c4fd06 2004-04-21 devnull 				n = readn(p[0], buf, sizeof buf-1);
 42 06c4fd06 2004-04-21 devnull 				close(p[0]);
 43 06c4fd06 2004-04-21 devnull 				if(!WIFEXITED(status) || WEXITSTATUS(status)!=0 || n <= 0){
 44 06c4fd06 2004-04-21 devnull 					werrstr("pipe dance failed in rfork");
 45 06c4fd06 2004-04-21 devnull 					return -1;
 46 06c4fd06 2004-04-21 devnull 				}
 47 06c4fd06 2004-04-21 devnull 				buf[n] = 0;
 48 06c4fd06 2004-04-21 devnull 				n = strtol(buf, &q, 0);
 49 06c4fd06 2004-04-21 devnull 				if(*q != 0){
 50 06c4fd06 2004-04-21 devnull 					werrstr("%s", q);
 51 06c4fd06 2004-04-21 devnull 					return -1;
 52 06c4fd06 2004-04-21 devnull 				}
 53 06c4fd06 2004-04-21 devnull 				pid = n;
 54 06c4fd06 2004-04-21 devnull 			}else{
 55 06c4fd06 2004-04-21 devnull 				/*
 56 06c4fd06 2004-04-21 devnull 				 * Child - fork a new child whose wait message can't 
 57 06c4fd06 2004-04-21 devnull 				 * get back to the parent because we're going to exit!
 58 06c4fd06 2004-04-21 devnull 				 */
 59 06c4fd06 2004-04-21 devnull 				signal(SIGCHLD, SIG_IGN);
 60 06c4fd06 2004-04-21 devnull 				close(p[0]);
 61 06c4fd06 2004-04-21 devnull 				pid = fork();
 62 06c4fd06 2004-04-21 devnull 				if(pid){
 63 06c4fd06 2004-04-21 devnull 					/* Child parent - send status over pipe and exit. */
 64 06c4fd06 2004-04-21 devnull 					if(pid > 0)
 65 06c4fd06 2004-04-21 devnull 						fprint(p[1], "%d", pid);
 66 06c4fd06 2004-04-21 devnull 					else
 67 06c4fd06 2004-04-21 devnull 						fprint(p[1], " %r");
 68 06c4fd06 2004-04-21 devnull 					close(p[1]);
 69 06c4fd06 2004-04-21 devnull 					_exit(0);
 70 06c4fd06 2004-04-21 devnull 				}else{
 71 06c4fd06 2004-04-21 devnull 					/* Child child - close pipe. */
 72 06c4fd06 2004-04-21 devnull 					close(p[1]);
 73 06c4fd06 2004-04-21 devnull 				}
 74 06c4fd06 2004-04-21 devnull 			}
 75 06c4fd06 2004-04-21 devnull 		}
 76 175b8a53 2004-04-21 devnull 		_p9uproc(0);
 77 1c8efa18 2003-12-04 devnull 		if(pid != 0)
 78 1c8efa18 2003-12-04 devnull 			return pid;
 79 1c8efa18 2003-12-04 devnull 	}
 80 fd04aace 2003-11-23 devnull 	if(flags&RFPROC){
 81 32f69c36 2003-12-11 devnull 		werrstr("cannot use rfork for shared memory -- use ffork");
 82 fd04aace 2003-11-23 devnull 		return -1;
 83 fd04aace 2003-11-23 devnull 	}
 84 32f69c36 2003-12-11 devnull 	if(flags&RFNAMEG){
 85 32f69c36 2003-12-11 devnull 		/* XXX set $NAMESPACE to a new directory */
 86 32f69c36 2003-12-11 devnull 		flags &= ~RFNAMEG;
 87 32f69c36 2003-12-11 devnull 	}
 88 fd04aace 2003-11-23 devnull 	if(flags&RFNOTEG){
 89 1c253ceb 2003-11-23 devnull 		setpgid(0, getpid());
 90 fd04aace 2003-11-23 devnull 		flags &= ~RFNOTEG;
 91 fd04aace 2003-11-23 devnull 	}
 92 06c4fd06 2004-04-21 devnull 	if(flags&RFNOWAIT){
 93 06c4fd06 2004-04-21 devnull 		werrstr("cannot use RFNOWAIT without RFPROC");
 94 06c4fd06 2004-04-21 devnull 		return -1;
 95 06c4fd06 2004-04-21 devnull 	}
 96 fd04aace 2003-11-23 devnull 	if(flags){
 97 fd04aace 2003-11-23 devnull 		werrstr("unknown flags %08ux in rfork", flags);
 98 fd04aace 2003-11-23 devnull 		return -1;
 99 fd04aace 2003-11-23 devnull 	}
100 fd04aace 2003-11-23 devnull 	return 0;
101 fd04aace 2003-11-23 devnull }