[libvirt] [PATCH] virNetClientSetTLSSession: Restore original signal mask

[Michal Privoznik]

Currently, we use pthread_sigmask(SIG_BLOCK, ...) prior to calling
poll(). This is okay, as we don't want poll() to be interrupted.
However, then - immediately as we fall out from the poll() - we try to
restore the original sigmask - again using SIG_BLOCK. But as the man
page says, SIG_BLOCK adds signals to the signal mask:

SIG_BLOCK
      The set of blocked signals is the union of the current set and the set argument.

Therefore, when restoring the original mask, we need to completely
overwrite the one we set earlier and hence we should be using:

SIG_SETMASK
      The set of blocked signals is set to the argument set.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---

Notes:
    This is a very old bug. It's worth backporting onto all maint branches we have.

 src/rpc/virnetclient.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/rpc/virnetclient.c b/src/rpc/virnetclient.c
index b288b74..255997b 100644
--- a/src/rpc/virnetclient.c
+++ b/src/rpc/virnetclient.c
@@ -792,7 +792,7 @@ int virNetClientSetTLSSession(virNetClientPtr client,
         if (ret < 0 && (errno == EAGAIN || errno == EINTR))
             goto repoll;
 
-        ignore_value(pthread_sigmask(SIG_BLOCK, &oldmask, NULL));
+        ignore_value(pthread_sigmask(SIG_SETMASK, &oldmask, NULL));
     }
 
     ret = virNetTLSContextCheckCertificate(tls, client->tls);
@@ -816,7 +816,7 @@ int virNetClientSetTLSSession(virNetClientPtr client,
     if (ret < 0 && (errno == EAGAIN || errno == EINTR))
         goto repoll2;
 
-    ignore_value(pthread_sigmask(SIG_BLOCK, &oldmask, NULL));
+    ignore_value(pthread_sigmask(SIG_SETMASK, &oldmask, NULL));
 
     len = virNetTLSSessionRead(client->tls, buf, 1);
     if (len < 0 && errno != ENOMSG) {
-- 
1.9.0