add HISTORY to various man pages

[plan9front.git] / sys / src / libthread / ioproc.c

diff --git a/sys/src/libthread/ioproc.c b/sys/src/libthread/ioproc.c
index 8a02e23e0250e5cf1deb1636b4c89f5dc759e309..32be310261b10401d0e6ff4faaa99dc0a7eb3a51 100644 (file)
--- a/sys/src/libthread/ioproc.c
+++ b/sys/src/libthread/ioproc.c
@@ -11,6 +11,8 @@ enum
 void
 iointerrupt(Ioproc *io)
 {
+       if(io->ctl < 0)
+               return;
        qlock(io);
        if(++io->intr == 1)
                write(io->ctl, "interrupt", 9);
@@ -28,18 +30,20 @@ xioproc(void *a)
        if(io = mallocz(sizeof(*io), 1)){
                char buf[128];
 
+               /*
+                * open might fail, ignore it for programs like factotum
+                * that don't use iointerrupt() anyway.
+                */
                snprint(buf, sizeof(buf), "/proc/%d/ctl", getpid());
-               if((io->ctl = open(buf, OWRITE)) < 0){
+               io->ctl = open(buf, OWRITE);
+
+               if((io->creply = chancreate(sizeof(void*), 0)) == nil){
+                       if(io->ctl >= 0)
+                               close(io->ctl);
                        free(io);
                        io = nil;
-               } else {
-                       if((io->creply = chancreate(sizeof(void*), 0)) == nil){
-                               close(io->ctl);
-                               free(io);
-                               io = nil;
-                       } else
-                               io->c = c;
-               }
+               } else
+                       io->c = c;
        }
        while(send(c, &io) < 0)
                ;
@@ -59,14 +63,16 @@ xioproc(void *a)
                qlock(io);
                if(io->intr){
                        io->intr = 0;
-                       write(io->ctl, "nointerrupt", 11);
+                       if(io->ctl >= 0)
+                               write(io->ctl, "nointerrupt", 11);
                }
                while(send(io->creply, &r) < 0)
                        ;
                qunlock(io);
        }
 
-       close(io->ctl);
+       if(io->ctl >= 0)
+               close(io->ctl);
        chanfree(io->c);
        chanfree(io->creply);
        free(io);