On Sat, May 05, 2018 at 12:48:45 -0500, Chris Venteicher wrote:
> Start and connect to QEMU so QMP commands can be performed.
>
> Isolates code for starting QEMU and establishing Monitor connections
> from code for obtaining capabilities so that arbitrary QMP commands can
> be exchanged with QEMU.
> ---
> src/qemu/qemu_capabilities.c | 59 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 59 insertions(+)
>
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index afce3eb2b7..097985cbe7 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -4303,6 +4303,65 @@ virQEMUCapsInitQMPCommandRun(virQEMUCapsInitQMPCommandPtr cmd,
> }
>
>
> +/* Start and connect to QEMU so QMP commands can be performed.
> + */
> +static virQEMUCapsInitQMPCommandPtr
> +virQEMUCapsSpinUpQemu(const char *exec,
> + const char *libDir, uid_t runUid, gid_t runGid,
> + bool forceTCG)
This wrapper should have a different signature (accepting qemuCaps), and
probably a different name which would suggest it's for onetime QMP
commands. I'm not sure what the right name would be, though :-)
> +{
> + virQEMUCapsInitQMPCommandPtr cmd = NULL;
> + virQEMUCapsInitQMPCommandPtr rtn_cmd = NULL;
> + char *binary = NULL;
> +
> + if (exec) {
> + if (VIR_STRDUP(binary, exec) < 0)
> + goto cleanup;
> + } else {
> + /* Check for existence of base emulator, or alternate base
> + * which can be used with magic cpu choice
> + */
> + virArch arch = virArchFromHost();
> + binary = virQEMUCapsFindBinaryForArch(arch, arch);
> + }
> +
> + VIR_DEBUG("binary=%s", binary);
We have a cache of QEMU capabilities for all binaries we found so
there's no need to try to look for them again.
> +
> + /* Make sure the binary we are about to try exec'ing exists.
> + * Technically we could catch the exec() failure, but that's
> + * in a sub-process so it's hard to feed back a useful error.
> + */
> + if (!virFileIsExecutable(binary)) {
> + virReportSystemError(errno, _("QEMU binary %s is not executable"),
> + binary);
> + goto cleanup;
> + }
Getting qemuCaps from the cache will also make sure the binary is
executable.
> +
> + if (!(cmd = virQEMUCapsInitQMPCommandNew(binary, libDir,
> + runUid, runGid, NULL)))
> + goto cleanup;
This will use capabilities.monitor.sock and capabilities.pidfile for all
processes. We either need to serialize this code with caps probing and
also serialize all threads running baseline/compare QMP commands, or we
need to refactor virQEMUCapsInitQMPCommandNew a bit so that it can be
used simultaneously by several threads.
> +
> + if ((virQEMUCapsInitQMPCommandRun(cmd, forceTCG)) < 0) {
No need for extra () since there's no assignment here.
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("Error starting QEMU"));
This would override any useful error already set by
virQEMUCapsInitQMPCommandRun.
> + goto cleanup;
> + }
> +
> + if (!(cmd->mon)) {
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> + _("Error connecting to QEMU"));
> + goto cleanup;
> + }
We should just check virQEMUCapsInitQMPCommandRun returned 0 and fail
otherwise.
> +
> + VIR_STEAL_PTR(rtn_cmd, cmd);
> +
> + cleanup:
> + virQEMUCapsInitQMPCommandFree(cmd);
> + VIR_FREE(binary);
> +
> + return rtn_cmd;
> +}
> +
> +
> static int
> virQEMUCapsInitQMP(virQEMUCapsPtr qemuCaps,
> const char *libDir,
> --
> 2.14.1
>
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