[PATCH v2 2/4] lib: Introduce 'virDomainQemuMonitorCommandWithFiles'
Peter Krempa
pkrempa at redhat.com
Mon Feb 21 08:41:07 UTC 2022
This API has the same semantics as 'virDomainQemuMonitorCommand' but
accepts file descriptors which are then forwarded to qemu.
Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
include/libvirt/libvirt-qemu.h | 8 +++
src/driver-hypervisor.h | 10 ++++
src/libvirt-qemu.c | 89 +++++++++++++++++++++++++++++
src/libvirt_qemu.syms | 5 ++
src/qemu_protocol-structs | 9 +++
src/remote/qemu_protocol.x | 20 ++++++-
src/remote/remote_daemon_dispatch.c | 62 ++++++++++++++++++++
src/remote/remote_driver.c | 57 ++++++++++++++++++
8 files changed, 259 insertions(+), 1 deletion(-)
diff --git a/include/libvirt/libvirt-qemu.h b/include/libvirt/libvirt-qemu.h
index 0cc2872821..98f2ac3823 100644
--- a/include/libvirt/libvirt-qemu.h
+++ b/include/libvirt/libvirt-qemu.h
@@ -37,6 +37,14 @@ typedef enum {
int virDomainQemuMonitorCommand(virDomainPtr domain, const char *cmd,
char **result, unsigned int flags);
+int virDomainQemuMonitorCommandWithFiles(virDomainPtr domain,
+ const char *cmd,
+ unsigned int ninfiles,
+ int *infiles,
+ unsigned int *noutfiles,
+ int **outfiles,
+ char **result,
+ unsigned int flags);
virDomainPtr virDomainQemuAttach(virConnectPtr domain,
unsigned int pid_value,
diff --git a/src/driver-hypervisor.h b/src/driver-hypervisor.h
index c83fb648a2..4423eb0885 100644
--- a/src/driver-hypervisor.h
+++ b/src/driver-hypervisor.h
@@ -874,6 +874,15 @@ typedef int
const char *cmd,
char **result,
unsigned int flags);
+typedef int
+(*virDrvDomainQemuMonitorCommandWithFiles)(virDomainPtr domain,
+ const char *cmd,
+ unsigned int ninfiles,
+ int *infiles,
+ unsigned int *noutfiles,
+ int **outfiles,
+ char **result,
+ unsigned int flags);
typedef char *
(*virDrvDomainQemuAgentCommand)(virDomainPtr domain,
@@ -1597,6 +1606,7 @@ struct _virHypervisorDriver {
virDrvDomainRevertToSnapshot domainRevertToSnapshot;
virDrvDomainSnapshotDelete domainSnapshotDelete;
virDrvDomainQemuMonitorCommand domainQemuMonitorCommand;
+ virDrvDomainQemuMonitorCommandWithFiles domainQemuMonitorCommandWithFiles;
virDrvDomainQemuAttach domainQemuAttach;
virDrvDomainQemuAgentCommand domainQemuAgentCommand;
virDrvConnectDomainQemuMonitorEventRegister connectDomainQemuMonitorEventRegister;
diff --git a/src/libvirt-qemu.c b/src/libvirt-qemu.c
index 1afb5fe529..9e80577b56 100644
--- a/src/libvirt-qemu.c
+++ b/src/libvirt-qemu.c
@@ -96,6 +96,95 @@ virDomainQemuMonitorCommand(virDomainPtr domain, const char *cmd,
}
+/**
+ * virDomainQemuMonitorCommandWithFiles:
+ * @domain: a domain object
+ * @cmd: the qemu monitor command string
+ * @ninfiles: number of filedescriptors passed in @infiles
+ * @infiles: filedescriptors to be passed to qemu with the command
+ * @noutfiles: if non-NULL filled with number of returned file descriptors
+ * @outfiles: if non-NULL filled with an array of returned file descriptors
+ * @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 @infiles to
+ * @domain through the qemu monitor and optionally return file descriptors via
+ * @outfiles. 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 ninfiles,
+ int *infiles,
+ unsigned int *noutfiles,
+ int **outfiles,
+ char **result,
+ unsigned int flags)
+{
+ virConnectPtr conn;
+
+ VIR_DOMAIN_DEBUG(domain,
+ "cmd=%s, ninfiles=%u, infiles=%p, noutfiles=%p, outfiles=%p, result=%p, flags=0x%x",
+ cmd, ninfiles, infiles, noutfiles, outfiles, result, flags);
+
+ virResetLastError();
+
+ virCheckDomainReturn(domain, -1);
+ conn = domain->conn;
+
+ if (ninfiles > 0 || outfiles) {
+ int rc;
+ if ((rc = VIR_DRV_SUPPORTS_FEATURE(conn->driver, conn,
+ VIR_DRV_FEATURE_FD_PASSING) <= 0)) {
+ if (rc == 0)
+ virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
+ _("fd passing is not supported by this connection"));
+ goto error;
+ }
+ }
+
+ virCheckNonNullArgGoto(result, error);
+ virCheckReadOnlyGoto(conn->flags, error);
+
+ if (conn->driver->domainQemuMonitorCommandWithFiles) {
+ int ret;
+ ret = conn->driver->domainQemuMonitorCommandWithFiles(domain, cmd,
+ ninfiles, infiles,
+ noutfiles, outfiles,
+ result, flags);
+ if (ret < 0)
+ goto error;
+ return ret;
+ }
+
+ virReportUnsupportedError();
+
+ error:
+ virDispatchError(conn);
+ return -1;
+}
+
/**
* virDomainQemuAttach:
* @conn: pointer to a hypervisor connection
diff --git a/src/libvirt_qemu.syms b/src/libvirt_qemu.syms
index 3a297e3a2b..019e545101 100644
--- a/src/libvirt_qemu.syms
+++ b/src/libvirt_qemu.syms
@@ -30,3 +30,8 @@ LIBVIRT_QEMU_1.2.3 {
virConnectDomainQemuMonitorEventDeregister;
virConnectDomainQemuMonitorEventRegister;
} LIBVIRT_QEMU_0.10.0;
+
+LIBVIRT_QEMU_8.1.0 {
+ global:
+ virDomainQemuMonitorCommandWithFiles;
+} LIBVIRT_QEMU_1.2.3;
diff --git a/src/qemu_protocol-structs b/src/qemu_protocol-structs
index 8501543cd9..ea0854385f 100644
--- a/src/qemu_protocol-structs
+++ b/src/qemu_protocol-structs
@@ -47,6 +47,14 @@ struct qemu_domain_monitor_event_msg {
u_int micros;
remote_string details;
};
+struct qemu_domain_monitor_command_with_files_args {
+ remote_nonnull_domain dom;
+ remote_nonnull_string cmd;
+ u_int flags;
+};
+struct qemu_domain_monitor_command_with_files_ret {
+ remote_nonnull_string result;
+};
enum qemu_procedure {
QEMU_PROC_DOMAIN_MONITOR_COMMAND = 1,
QEMU_PROC_DOMAIN_ATTACH = 2,
@@ -54,4 +62,5 @@ enum qemu_procedure {
QEMU_PROC_CONNECT_DOMAIN_MONITOR_EVENT_REGISTER = 4,
QEMU_PROC_CONNECT_DOMAIN_MONITOR_EVENT_DEREGISTER = 5,
QEMU_PROC_DOMAIN_MONITOR_EVENT = 6,
+ QEMU_PROC_DOMAIN_MONITOR_COMMAND_WITH_FILES = 7,
};
diff --git a/src/remote/qemu_protocol.x b/src/remote/qemu_protocol.x
index 8ff5dc8568..c7f3abfcbf 100644
--- a/src/remote/qemu_protocol.x
+++ b/src/remote/qemu_protocol.x
@@ -79,6 +79,17 @@ struct qemu_domain_monitor_event_msg {
remote_string details;
};
+struct qemu_domain_monitor_command_with_files_args {
+ remote_nonnull_domain dom;
+ remote_nonnull_string cmd;
+ unsigned int flags;
+};
+
+struct qemu_domain_monitor_command_with_files_ret {
+ remote_nonnull_string result;
+};
+
+
/* Define the program number, protocol version and procedure numbers here. */
const QEMU_PROGRAM = 0x20008087;
const QEMU_PROTOCOL_VERSION = 1;
@@ -151,5 +162,12 @@ enum qemu_procedure {
* @generate: both
* @acl: none
*/
- QEMU_PROC_DOMAIN_MONITOR_EVENT = 6
+ QEMU_PROC_DOMAIN_MONITOR_EVENT = 6,
+
+ /**
+ * @generate: none
+ * @priority: low
+ * @acl: domain:write
+ */
+ QEMU_PROC_DOMAIN_MONITOR_COMMAND_WITH_FILES = 7
};
diff --git a/src/remote/remote_daemon_dispatch.c b/src/remote/remote_daemon_dispatch.c
index 587cc0b3a5..510856024c 100644
--- a/src/remote/remote_daemon_dispatch.c
+++ b/src/remote/remote_daemon_dispatch.c
@@ -4684,6 +4684,68 @@ qemuDispatchDomainMonitorCommand(virNetServer *server G_GNUC_UNUSED,
}
+static int
+qemuDispatchDomainMonitorCommandWithFiles(virNetServer *server G_GNUC_UNUSED,
+ virNetServerClient *client,
+ virNetMessage *msg,
+ struct virNetMessageError *rerr,
+ qemu_domain_monitor_command_with_files_args *args,
+ qemu_domain_monitor_command_with_files_ret *ret)
+{
+ virDomainPtr dom = NULL;
+ int *infiles = NULL;
+ unsigned int ninfiles = 0;
+ int *outfiles = NULL;
+ unsigned int noutfiles = 0;
+ int rv = -1;
+ virConnectPtr conn = remoteGetHypervisorConn(client);
+ size_t i;
+
+ if (!conn)
+ goto cleanup;
+
+ if (!(dom = get_nonnull_domain(conn, args->dom)))
+ goto cleanup;
+
+ infiles = g_new0(int, msg->nfds);
+ for (i = 0; i < msg->nfds; i++) {
+ if ((infiles[i] = virNetMessageDupFD(msg, i)) < 0)
+ goto cleanup;
+ ninfiles++;
+ }
+
+ /* This API can both receive FDs from the client and send FDs back, but 'msg'
+ * is being reused. Thus we must clear the list of FDs in it to prevent
+ * us sending back the FDs client sent us. */
+ virNetMessageClearFDs(msg);
+
+ if (virDomainQemuMonitorCommandWithFiles(dom, args->cmd, ninfiles, infiles,
+ &noutfiles, &outfiles,
+ &ret->result, args->flags) < 0)
+ goto cleanup;
+
+ for (i = 0; i < noutfiles; i++) {
+ if (virNetMessageAddFD(msg, outfiles[i]) < 0)
+ goto cleanup;
+ }
+
+ /* return 1 here to let virNetServerProgramDispatchCall know we are passing fds */
+ if (noutfiles > 0)
+ rv = 1;
+ else
+ rv = 0;
+
+ cleanup:
+ for (i = 0; i < noutfiles; i++)
+ VIR_FORCE_CLOSE(outfiles[i]);
+
+ if (rv < 0)
+ virNetMessageSaveError(rerr);
+ virObjectUnref(dom);
+ return rv;
+}
+
+
static int
remoteDispatchDomainMigrateBegin3(virNetServer *server G_GNUC_UNUSED,
virNetServerClient *client,
diff --git a/src/remote/remote_driver.c b/src/remote/remote_driver.c
index d721da6d2d..4babfbaa94 100644
--- a/src/remote/remote_driver.c
+++ b/src/remote/remote_driver.c
@@ -5931,6 +5931,62 @@ remoteDomainQemuMonitorCommand(virDomainPtr domain, const char *cmd,
}
+static int
+remoteDomainQemuMonitorCommandWithFiles(virDomainPtr domain,
+ const char *cmd,
+ unsigned int ninfiles,
+ int *infiles,
+ unsigned int *noutfiles,
+ int **outfiles,
+ char **result,
+ unsigned int flags)
+{
+ int rv = -1;
+ qemu_domain_monitor_command_with_files_args args;
+ qemu_domain_monitor_command_with_files_ret ret;
+ struct private_data *priv = domain->conn->privateData;
+ size_t rpc_noutfiles = 0;
+ g_autofree int *rpc_outfiles = NULL;
+ size_t i;
+
+ remoteDriverLock(priv);
+
+ make_nonnull_domain(&args.dom, domain);
+ args.cmd = (char *)cmd;
+ args.flags = flags;
+
+ memset(&ret, 0, sizeof(ret));
+ if (callFull(domain->conn, priv, REMOTE_CALL_QEMU,
+ infiles, ninfiles, &rpc_outfiles, &rpc_noutfiles,
+ QEMU_PROC_DOMAIN_MONITOR_COMMAND_WITH_FILES,
+ (xdrproc_t) xdr_qemu_domain_monitor_command_with_files_args, (char *) &args,
+ (xdrproc_t) xdr_qemu_domain_monitor_command_with_files_ret, (char *) &ret) == -1)
+ goto done;
+
+ if (outfiles)
+ *outfiles = g_steal_pointer(&rpc_outfiles);
+
+ if (noutfiles)
+ *noutfiles = rpc_noutfiles;
+
+ *result = g_strdup(ret.result);
+
+ rv = 0;
+
+ xdr_free((xdrproc_t) xdr_qemu_domain_monitor_command_with_files_ret, (char *) &ret);
+
+ done:
+ if (rpc_outfiles) {
+ for (i = 0; rpc_noutfiles < i; i++) {
+ VIR_FORCE_CLOSE(rpc_outfiles[i]);
+ }
+ }
+
+ remoteDriverUnlock(priv);
+ return rv;
+}
+
+
static char *
remoteDomainMigrateBegin3(virDomainPtr domain,
const char *xmlin,
@@ -8506,6 +8562,7 @@ static virHypervisorDriver hypervisor_driver = {
.domainSnapshotHasMetadata = remoteDomainSnapshotHasMetadata, /* 0.9.13 */
.domainSnapshotDelete = remoteDomainSnapshotDelete, /* 0.8.0 */
.domainQemuMonitorCommand = remoteDomainQemuMonitorCommand, /* 0.8.3 */
+ .domainQemuMonitorCommandWithFiles = remoteDomainQemuMonitorCommandWithFiles, /* 8.1.0 */
.domainQemuAttach = remoteDomainQemuAttach, /* 0.9.4 */
.domainQemuAgentCommand = remoteDomainQemuAgentCommand, /* 0.10.0 */
.connectDomainQemuMonitorEventRegister = remoteConnectDomainQemuMonitorEventRegister, /* 1.2.3 */
--
2.35.1
More information about the libvir-list
mailing list