On Sun, 18 Mar 2007 at 20:05, Henning Brauer wrote:

> * Valentin Kozamernik <tin@komna.com> [2007-03-18 16:25]:
> > The imsg_read() function uses read(2) and returns 0 on EOF, EINTR or
> > EAGAIN. But whereever imsg_read() is used it is assumed that the
> > return value of 0 means that the socket has been closed.
>
> imsg_read actually uses recvmsg(2), but that doesn't really make a
> difference.

Well, I've checked it again; ntpd users read(2), bgpd uses recvmsg(2)
and ospfd uses recv(2).


> you are correct insofar that the return(0) there is incorrect.
> after looking at things a bit I believe we get away with returning -2

Yes, that is what I was thinking too. Here is a possible patch (which
I currently can not test properly!):


Index: usr.sbin/bgpd/control.c
================================================== =================
RCS file: /cvs/src/usr.sbin/bgpd/control.c,v
retrieving revision 1.53
diff -u -r1.53 control.c
--- usr.sbin/bgpd/control.c 2006/08/23 08:13:04 1.53
+++ usr.sbin/bgpd/control.c 2007/03/18 22:21:01
@@ -209,7 +209,7 @@
if (!(pfd->revents & POLLIN))
return (0);

- if (imsg_read(&c->ibuf) <= 0) {
+ if ((n = imsg_read(&c->ibuf)) == -1 || n == 0) {
*ctl_cnt -= control_close(pfd->fd);
return (1);
}
Index: usr.sbin/bgpd/imsg.c
================================================== =================
RCS file: /cvs/src/usr.sbin/bgpd/imsg.c,v
retrieving revision 1.38
diff -u -r1.38 imsg.c
--- usr.sbin/bgpd/imsg.c 2006/05/27 19:59:44 1.38
+++ usr.sbin/bgpd/imsg.c 2007/03/18 22:21:01
@@ -61,7 +61,7 @@
log_warn("imsg_read: pipe read error");
return (-1);
}
- return (0);
+ return (-2);
}

ibuf->r.wpos += n;
Index: usr.sbin/ntpd/imsg.c
================================================== =================
RCS file: /cvs/src/usr.sbin/ntpd/imsg.c,v
retrieving revision 1.11
diff -u -r1.11 imsg.c
--- usr.sbin/ntpd/imsg.c 2005/04/26 15:18:22 1.11
+++ usr.sbin/ntpd/imsg.c 2007/03/18 22:21:02
@@ -46,7 +46,7 @@
log_warn("imsg_read: pipe read error");
return (-1);
}
- return (0);
+ return (-2);
}

ibuf->r.wpos += n;
Index: usr.sbin/ospfd/control.c
================================================== =================
RCS file: /cvs/src/usr.sbin/ospfd/control.c,v
retrieving revision 1.16
diff -u -r1.16 control.c
--- usr.sbin/ospfd/control.c 2007/01/23 17:39:33 1.16
+++ usr.sbin/ospfd/control.c 2007/03/18 22:21:02
@@ -197,7 +197,7 @@

switch (event) {
case EV_READ:
- if ((n = imsg_read(&c->ibuf)) <= 0) {
+ if ((n = imsg_read(&c->ibuf)) == -1 || n == 0) {
control_close(fd);
return;
}
Index: usr.sbin/ospfd/imsg.c
================================================== =================
RCS file: /cvs/src/usr.sbin/ospfd/imsg.c,v
retrieving revision 1.7
diff -u -r1.7 imsg.c
--- usr.sbin/ospfd/imsg.c 2006/05/27 20:07:42 1.7
+++ usr.sbin/ospfd/imsg.c 2007/03/18 22:21:02
@@ -50,7 +50,7 @@
log_warn("imsg_read: pipe read error");
return (-1);
}
- return (0);
+ return (-2);
}

ibuf->r.wpos += n;



--
Tin