macvtap: log an error if on failure to connect to netlink socket

A bug in libnl (see https://bugzilla.redhat.com/show_bug.cgi?id=677724
and https://bugzilla.redhat.com/show_bug.cgi?id=677725) makes it very
easy to create a failure to connect to the netlink socket when trying
to open a macvtap network device ("type='direct'" in domain interface
XML). When that error occurred (during a call to libnl's nl_connect()
from libvirt's nlComm(), there was no log message, leading virsh (for
example) to report "unknown error".

There were two other cases in nlComm where an error in a libnl
function might return with failure but no error reported. In all three
cases, this patch logs a message which will hopefully be more useful.

Note that more detailed information about the failure might be
available from libnl's nl_geterror() function, but it calls
strerror(), which is not threadsafe, so we can't use it.
This commit is contained in:
Laine Stump 2011-03-15 16:22:25 -04:00
parent 98a4e5a301
commit 12775d9491

View File

@ -120,13 +120,18 @@ int nlComm(struct nl_msg *nl_msg,
fd_set readfds;
int fd;
int n;
struct nl_handle *nlhandle = nl_handle_alloc();
struct nlmsghdr *nlmsg = nlmsg_hdr(nl_msg);
struct nl_handle *nlhandle = nl_handle_alloc();
if (!nlhandle)
if (!nlhandle) {
virReportSystemError(errno,
"%s", _("cannot allocate nlhandle for netlink"));
return -1;
}
if (nl_connect(nlhandle, NETLINK_ROUTE) < 0) {
virReportSystemError(errno,
"%s", _("cannot connect to netlink socket"));
rc = -1;
goto err_exit;
}
@ -161,9 +166,11 @@ int nlComm(struct nl_msg *nl_msg,
}
*respbuflen = nl_recv(nlhandle, &nladdr, respbuf, NULL);
if (*respbuflen <= 0)
if (*respbuflen <= 0) {
virReportSystemError(errno,
"%s", _("nl_recv failed"));
rc = -1;
}
err_exit:
if (rc == -1) {
VIR_FREE(*respbuf);