On Thu, Dec 06, 2012 at 14:00:00 +0100, Michal Privoznik wrote:

If debugging is enabled, the debug messages are sent to stderr. Moreover, if a command has catching of stderr set, the messages gets mixed with stdout output (assuming both outputs are stored in the same variable). The resulting string then doesn't necessarily have to start with desired prefix then. This bug exposes itself when parsing dnsmasq output:

2012-12-06 11:18:11.445+0000: 18491: error : dnsmasqCapsSetFromBuffer:664 : internal error cannot parse /usr/sbin/dnsmasq version number in '2012-12-06 11:11:02.232+0000: 18492: debug : virFileClose:72 : Closed fd 22'

We can clearly see that the output of dnsmasq --version doesn't start with expected "Dnsmasq version " string but a libvirt debug output. --- src/util/dnsmasq.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/src/util/dnsmasq.c b/src/util/dnsmasq.c index de0293a..a627ed2 100644 --- a/src/util/dnsmasq.c +++ b/src/util/dnsmasq.c @@ -715,7 +715,6 @@ dnsmasqCapsRefreshInternal(dnsmasqCapsPtr caps, bool force)

cmd = virCommandNewArgList(caps->binaryPath, "--version", NULL); virCommandSetOutputBuffer(cmd, &version); - virCommandSetErrorBuffer(cmd, &version); virCommandAddEnvPassCommon(cmd); virCommandClearCaps(cmd); if (virCommandRun(cmd, NULL) < 0) { @@ -727,7 +726,6 @@ dnsmasqCapsRefreshInternal(dnsmasqCapsPtr caps, bool force)

cmd = virCommandNewArgList(caps->binaryPath, "--help", NULL); virCommandSetOutputBuffer(cmd, &help); - virCommandSetErrorBuffer(cmd, &help); virCommandAddEnvPassCommon(cmd); virCommandClearCaps(cmd); if (virCommandRun(cmd, NULL) < 0) {

ACK, this looks like the right solution. Jirka