Re: [libvirt] [PATCH] util: change virFile*Pid functions to return < 0 on failure

Although most functions in libvirt return 0 on success and< 0 on failure, there are a few functions lingering around that return errno (a positive value) on failure, and sometimes code calling those functions incorrectly assumes the<0 standard. I noticed one of these the other day when auditing networkStartDhcpDaemon after Guido Gunther found a place where success was improperly returned on failure (that patch has been acked and is pending a push). The problem was that it expected the return value from virFileReadPid to be< 0 on failure, but it was actually positive (it was also neglected to set the return code in this case, similar to the bug found by Guido). This all led to the fact that *all* of the virFile*Pid functions in util.c are returning errno on failure. This patch remedies that problem by changing them all to return -errno on failure, and makes any necessary changes to callers of the functions. (In the meantime, I also properly set the return code on failure of virFileReadPid in networkStartDhcpDaemon).

+++ b/src/lxc/lxc_controller.c

@@ -996,5 +996,5 @@ cleanup: unlink(sockpath); VIR_FREE(sockpath); - return rc; + return -rc; /* rc is 0 or negative, but returns from main should be>=0 */