diff options
| -rw-r--r-- | src/lib9/rendez-signal.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/src/lib9/rendez-signal.c b/src/lib9/rendez-signal.c index 320bd11a..6c15e7ec 100644 --- a/src/lib9/rendez-signal.c +++ b/src/lib9/rendez-signal.c @@ -45,6 +45,7 @@ struct Vous Vous *link; Lock lk; int pid; + int wakeup; ulong val; ulong tag; }; @@ -149,8 +150,20 @@ rendezvous(ulong tag, ulong val) sigaddset(&mask, SIGUSR1); sigprocmask(SIG_SETMASK, &mask, NULL); sigdelset(&mask, SIGUSR1); + v->wakeup = 0; unlock(&v->lk); - sigsuspend(&mask); + for(;;){ + /* + * There may well be random signals flying around, + * so we can't be sure why we woke up. If we weren't + * properly awakened, we need to go back to sleep. + */ + sigsuspend(&mask); + lock(&v->lk); /* do some memory synchronization */ + unlock(&v->lk); + if(v->wakeup == 1) + break; + } rval = v->val; if(DBG)fprint(2, "pid is %d, awake\n", me); putvous(v); @@ -169,6 +182,7 @@ rendezvous(ulong tag, ulong val) lock(&v->lk); rval = v->val; v->val = val; + v->wakeup = 1; unlock(&v->lk); if(kill(vpid, SIGUSR1) < 0){ if(DBG)fprint(2, "pid is %d, kill %d failed: %r\n", me, vpid); |