Re: [PATCH 1/5] lib: Introduce 'virDomainQemuMonitorCommandWithFiles'

On 2/3/22 15:51, Peter Krempa wrote: > This API has the same semantics as 'virDomainQemuMonitorCommand' but > accepts file descriptors which are then forwarded to qemu. > > Signed-off-by: Peter Krempa <pkrempa(a)redhat.com&gt; > --- > include/libvirt/libvirt-qemu.h | 6 +++ > src/driver-hypervisor.h | 8 ++++ > src/libvirt-qemu.c | 71 +++++++++++++++++++++++++++++ > src/libvirt_qemu.syms | 5 ++ > src/qemu_protocol-structs | 9 ++++ > src/remote/qemu_protocol.x | 20 +++++++- > src/remote/remote_daemon_dispatch.c | 42 +++++++++++++++++ > src/remote/remote_driver.c | 40 ++++++++++++++++ > 8 files changed, 200 insertions(+), 1 deletion(-) > > diff --git a/include/libvirt/libvirt-qemu.h b/include/libvirt/libvirt-qemu.h > index 0cc2872821..eed691ec91 100644 > --- a/include/libvirt/libvirt-qemu.h > +++ b/include/libvirt/libvirt-qemu.h > @@ -37,6 +37,12 @@ typedef enum { > > int virDomainQemuMonitorCommand(virDomainPtr domain, const char *cmd, > char **result, unsigned int flags); > +int virDomainQemuMonitorCommandWithFiles(virDomainPtr domain, > + const char *cmd, > + unsigned int nfiles, > + int *files, Do we perhaps want to have another argument for fdOut (e.g. when QEMU would want to return an FD)? I don't think there is a command that would do that now, but who knows, maybe there will be someday.

> + char **result, > + unsigned int flags); > > virDomainPtr virDomainQemuAttach(virConnectPtr domain, > unsigned int pid_value,

> diff --git a/src/libvirt-qemu.c b/src/libvirt-qemu.c > index 1afb5fe529..1dbe0cba54 100644 > --- a/src/libvirt-qemu.c > +++ b/src/libvirt-qemu.c > @@ -96,6 +96,77 @@ virDomainQemuMonitorCommand(virDomainPtr domain, const char *cmd, > } > > > +/** > + * virDomainQemuMonitorCommandWithFiles: > + * @domain: a domain object > + * @cmd: the qemu monitor command string > + * @nfiles: number of filedescriptors passed in @files > + * @files: filedescriptors to be passed to qemu with the command > + * @result: a string returned by @cmd > + * @flags: bitwise-or of supported virDomainQemuMonitorCommandFlags > + * > + * This API is QEMU specific, so it will only work with hypervisor > + * connections to the QEMU driver with local connections using the unix socket. > + * > + * Send an arbitrary monitor command @cmd with file descriptors @files to > + * @domain through the qemu monitor. There are several requirements to safely > + * and successfully use this API: > + * > + * - A @cmd that queries state without making any modifications is safe > + * - A @cmd that alters state that is also tracked by libvirt is unsafe, > + * and may cause libvirtd to crash > + * - A @cmd that alters state not tracked by the current version of > + * libvirt is possible as a means to test new qemu features before > + * they have support in libvirt, but no guarantees are made to safety > + * > + * If VIR_DOMAIN_QEMU_MONITOR_COMMAND_HMP is set, the command is > + * considered to be a human monitor command and libvirt will automatically > + * convert it into QMP if needed. In that case the @result will also > + * be converted back from QMP. > + * > + * If successful, @result will be filled with the string output of the > + * @cmd, and the caller must free this string. > + * > + * Returns 0 in case of success, -1 in case of failure > + */ > +int > +virDomainQemuMonitorCommandWithFiles(virDomainPtr domain, > + const char *cmd, > + unsigned int nfiles, > + int *files, > + char **result, > + unsigned int flags) > +{ > + virConnectPtr conn; > + > + VIR_DOMAIN_DEBUG(domain, "cmd=%s, nfiles=%u, files=%p, result=%p, flags=0x%x", > + cmd, nfiles, files, result, flags); > + > + virResetLastError(); > + > + virCheckDomainReturn(domain, -1); > + conn = domain->conn; > + > + virCheckNonNullArgGoto(result, error); > + virCheckReadOnlyGoto(conn->flags, error); Missing VIR_DRV_SUPPORTS_FEATURE(conn->driver, conn, VIR_DRV_FEATURE_FD_PASSING); check.