[libvirt] [PATCH] add an assert, to avoid a false-positive NULL-deref warning from clang

Here's a case in which using an assertion appears to be the only way to tell clang that "client" really is non-NULL at that point. I'm sure clang's analyzers will eventually improve, and hence avoid this sort of false positive, so have marked this with a FIXME comment, to help ensure we eventually remove this otherwise unnecessary assertion. From: Jim Meyering <meyering(a)redhat.com&gt; Date: Mon, 1 Mar 2010 15:19:48 +0100 Subject: [PATCH] add an assert, to avoid a false-positive NULL-deref warning from clang * daemon/libvirtd.c (qemudWorker): Assert. --- daemon/libvirtd.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/daemon/libvirtd.c b/daemon/libvirtd.c index 9bdbecb..a357914 100644 --- a/daemon/libvirtd.c +++ b/daemon/libvirtd.c @@ -24,34 +24,35 @@ #include <config.h> #include <sys/types.h> #include <sys/wait.h> #include <sys/stat.h> #include <unistd.h> #include <fcntl.h> #include <limits.h> #include <sys/socket.h> #include <sys/un.h> #include <sys/poll.h> #include <netinet/in.h> #include <netinet/tcp.h> #include <netdb.h> #include <stdlib.h> #include <pwd.h> #include <stdio.h> +#include <assert.h> #include <stdarg.h> #include <syslog.h> #include <string.h> #include <errno.h> #include <getopt.h> #include <fnmatch.h> #include <grp.h> #include <signal.h> #include <netdb.h> #include "libvirt_internal.h" #include "virterror_internal.h" #define VIR_FROM_THIS VIR_FROM_QEMU #include "libvirtd.h" #include "dispatch.h" @@ -1504,34 +1505,38 @@ static void *qemudWorker(void *data) virMutexLock(&server->lock); while (((client = qemudPendingJob(server)) == NULL) && !worker->quitRequest) { if (virCondWait(&server->job, &server->lock) < 0) { virMutexUnlock(&server->lock); return NULL; } } if (worker->quitRequest) { if (client) virMutexUnlock(&client->lock); virMutexUnlock(&server->lock); return NULL; } worker->processingCall = 1; virMutexUnlock(&server->lock); + /* Tell clang we know what we're doing. + FIXME: remove when clang improves. */ + assert (client); + /* We own a locked client now... */ client->refs++; /* Remove our message from dispatch queue while we use it */ msg = qemudClientMessageQueueServe(&client->dx); /* This function drops the lock during dispatch, * and re-acquires it before returning */ if (remoteDispatchClientRequest (server, client, msg) < 0) { VIR_FREE(msg); qemudDispatchClientFailure(client); client->refs--; virMutexUnlock(&client->lock); continue; } client->refs--; -- 1.7.0.1.414.g89213d