Re: [libvirt] [PATCH RFC 08/22] qemu_process: Persist stderr in qemuProcess struct

A qemuProcess struct tracks the entire lifespan of a single QEMU Process including storing error output when the process terminates or activation fails. Error output remains available until qemuProcessFree is called. The qmperr buffer no longer needs to be maintained outside of the qemuProcess structure because the structure is used for a single QEMU process and the structures can be maintained as long as required to retrieve the process error info. Capabilities init code is refactored but continues to report QEMU process error data only when the initial (non KVM) QEMU process activation

fails to result in a usable monitor connection for retrieving capabilities. The VIR_ERR_INTERNAL_ERROR "Failed to probe QEMU binary" reporting is moved into virQEMUCapsInitQMP function and the stderr string is extracted from the qemuProcess struct using a macro to retrieve the string. The same error and log message should be generated, in the same conditions, after this patch as before. Signed-off-by: Chris Venteicher <cventeic(a)redhat.com&gt; --- src/qemu/qemu_capabilities.c | 27 ++++++++++++--------------- src/qemu/qemu_process.c | 12 ++++-------- src/qemu/qemu_process.h | 6 ++++-- 3 files changed, 20 insertions(+), 25 deletions(-) diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index a957c3bdbd..f5e327097e 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -4216,8 +4216,7 @@ static int virQEMUCapsInitQMP(virQEMUCapsPtr qemuCaps, const char *libDir, uid_t runUid, - gid_t runGid, - char **qmperr) + gid_t runGid)

{ qemuProcessPtr proc = NULL; qemuProcessPtr proc_kvm = NULL; @@ -4226,7 +4225,7 @@ virQEMUCapsInitQMP(virQEMUCapsPtr qemuCaps, bool forceTCG = false; if (!(proc = qemuProcessNew(qemuCaps->binary, libDir, - runUid, runGid, qmperr, forceTCG))) + runUid, runGid, forceTCG))) goto cleanup;

if ((rc = qemuProcessRun(proc)) != 0) { @@ -4242,7 +4241,7 @@ virQEMUCapsInitQMP(virQEMUCapsPtr qemuCaps, qemuProcessStopQmp(proc); forceTCG = true; - proc_kvm = qemuProcessNew(qemuCaps->binary, libDir, runUid, runGid, NULL, forceTCG); + proc_kvm = qemuProcessNew(qemuCaps->binary, libDir, runUid, runGid, forceTCG); if ((rc = qemuProcessRun(proc_kvm)) != 0) { if (rc == 1) @@ -4257,6 +4256,13 @@ virQEMUCapsInitQMP(virQEMUCapsPtr qemuCaps, ret = 0; cleanup: + if (proc && !proc->mon) {

+ char *err = QEMU_PROCESS_ERROR(proc) ? QEMU_PROCESS_ERROR(proc) : _("unknown error");

+ + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Failed to probe QEMU binary with QMP: %s"), err); + }

+ qemuProcessStopQmp(proc); qemuProcessStopQmp(proc_kvm); qemuProcessFree(proc); @@ -4296,7 +4302,6 @@ virQEMUCapsNewForBinaryInternal(virArch hostArch, { virQEMUCapsPtr qemuCaps; struct stat sb; - char *qmperr = NULL; if (!(qemuCaps = virQEMUCapsNew())) goto error; @@ -4323,15 +4328,8 @@ virQEMUCapsNewForBinaryInternal(virArch hostArch, goto error; } - if (virQEMUCapsInitQMP(qemuCaps, libDir, runUid, runGid, &qmperr) < 0) { - virQEMUCapsLogProbeFailure(binary); - goto error; - } - - if (!qemuCaps->usedQMP) { - virReportError(VIR_ERR_INTERNAL_ERROR, - _("Failed to probe QEMU binary with QMP: %s"), - qmperr ? qmperr : _("unknown error")); + if (virQEMUCapsInitQMP(qemuCaps, libDir, runUid, runGid) < 0 || + !qemuCaps->usedQMP) {

virQEMUCapsLogProbeFailure(binary); goto error; } @@ -4350,7 +4348,6 @@ virQEMUCapsNewForBinaryInternal(virArch hostArch, } cleanup: - VIR_FREE(qmperr); return qemuCaps; error:

diff --git a/src/qemu/qemu_process.h b/src/qemu/qemu_process.h index ab2640ce7c..abd80baf5c 100644 --- a/src/qemu/qemu_process.h +++ b/src/qemu/qemu_process.h @@ -220,7 +220,7 @@ struct _qemuProcess { char *binary; uid_t runUid; gid_t runGid; - char **qmperr; + char *qmperr; /* qemu process stderr */

char *monarg; char *monpath; char *pidfile; @@ -232,11 +232,13 @@ struct _qemuProcess { bool forceTCG; }; +#define QEMU_PROCESS_ERROR(proc) \ + ((char *) (proc ? proc->qmperr: NULL)) +

qemuProcessPtr qemuProcessNew(const char *binary, const char *libDir, uid_t runUid, gid_t runGid, - char **qmperr, bool forceTCG); void qemuProcessFree(qemuProcessPtr proc);