logging: add client for virtlogd daemon

Add the virLogManager API which allows for communication with
the virtlogd daemon to RPC program. This provides the client
side API to open log files for guest domains.

The virtlogd daemon is setup to auto-spawn on first use when
running unprivileged. For privileged usage, systemd socket
activation is used instead.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

po/POTFILES.in

@@ -82,6 +82,7 @@ src/logging/log_daemon.c
 src/logging/log_daemon_config.c
 src/logging/log_daemon_dispatch.c
 src/logging/log_handler.c
+src/logging/log_manager.c
 src/lxc/lxc_cgroup.c
 src/lxc/lxc_fuse.c
 src/lxc/lxc_hostdev.c

src/Makefile.am

@@ -216,7 +216,9 @@ DRIVER_SOURCES =							\
 		locking/lock_manager.c locking/lock_manager.h		\
 		locking/lock_driver.h					\
 		locking/lock_driver_nop.h locking/lock_driver_nop.c	\
-		locking/domain_lock.h locking/domain_lock.c
+		locking/domain_lock.h locking/domain_lock.c		\
+		logging/log_manager.c logging/log_manager.h		\
+		$(NULL)
 
 LOCK_DRIVER_SANLOCK_SOURCES = \
 		locking/lock_driver_sanlock.c

src/libvirt_private.syms

@@ -1004,6 +1004,14 @@ virLockManagerPluginUsesState;
 virLockManagerRelease;
 
 
+# logging/log_manager.h
+virLogManagerDomainGetLogFilePosition;
+virLogManagerDomainOpenLogFile;
+virLogManagerDomainReadLogFile;
+virLogManagerFree;
+virLogManagerNew;
+
+
 # nodeinfo.h
 nodeAllocPages;
 nodeCapsInitNUMA;

src/logging/log_manager.c

+/*
+ * log_manager.c: log management client
+ *
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library;  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Author: Daniel P. Berrange <berrange@redhat.com>
+ */
+
+#include <config.h>
+
+#include "configmake.h"
+
+#include "log_manager.h"
+#include "log_protocol.h"
+#include "viralloc.h"
+#include "virutil.h"
+#include "virstring.h"
+#include "virerror.h"
+#include "virfile.h"
+
+#include "rpc/virnetclient.h"
+
+#define VIR_FROM_THIS VIR_FROM_LOGGING
+
+struct _virLogManager {
+    virNetClientPtr client;
+    virNetClientProgramPtr program;
+    unsigned int serial;
+};
+
+
+static char *
+virLogManagerDaemonPath(bool privileged)
+{
+    char *path;
+    if (privileged) {
+        if (VIR_STRDUP(path, LOCALSTATEDIR "/run/libvirt/virtlogd-sock") < 0)
+            return NULL;
+    } else {
+        char *rundir = NULL;
+
+        if (!(rundir = virGetUserRuntimeDirectory()))
+            return NULL;
+
+        if (virAsprintf(&path, "%s/virtlogd-sock", rundir) < 0) {
+            VIR_FREE(rundir);
+            return NULL;
+        }
+
+        VIR_FREE(rundir);
+    }
+    return path;
+}
+
+
+static virNetClientPtr
+virLogManagerConnect(bool privileged,
+                     virNetClientProgramPtr *prog)
+{
+    virNetClientPtr client = NULL;
+    char *logdpath;
+    char *daemonPath = NULL;
+
+    *prog = NULL;
+
+    if (!(logdpath = virLogManagerDaemonPath(privileged)))
+        goto error;
+
+    if (!privileged &&
+        !(daemonPath = virFileFindResourceFull("virtlogd",
+                                               NULL, NULL,
+                                               abs_topbuilddir "/src",
+                                               SBINDIR,
+                                               "VIRTLOGD_PATH")))
+        goto error;
+
+    if (!(client = virNetClientNewUNIX(logdpath,
+                                       daemonPath != NULL,
+                                       daemonPath)))
+        goto error;
+
+    if (!(*prog = virNetClientProgramNew(VIR_LOG_MANAGER_PROTOCOL_PROGRAM,
+                                         VIR_LOG_MANAGER_PROTOCOL_PROGRAM_VERSION,
+                                         NULL,
+                                         0,
+                                         NULL)))
+        goto error;
+
+    if (virNetClientAddProgram(client, *prog) < 0)
+        goto error;
+
+    VIR_FREE(daemonPath);
+    VIR_FREE(logdpath);
+
+    return client;
+
+ error:
+    VIR_FREE(daemonPath);
+    VIR_FREE(logdpath);
+    virNetClientClose(client);
+    virObjectUnref(client);
+    virObjectUnref(*prog);
+    return NULL;
+}
+
+
+virLogManagerPtr
+virLogManagerNew(bool privileged)
+{
+    virLogManagerPtr mgr;
+
+    if (VIR_ALLOC(mgr) < 0)
+        goto error;
+
+    if (!(mgr->client = virLogManagerConnect(privileged, &mgr->program)))
+        goto error;
+
+    return mgr;
+
+ error:
+    virLogManagerFree(mgr);
+    return NULL;
+}
+
+
+void
+virLogManagerFree(virLogManagerPtr mgr)
+{
+    if (!mgr)
+        return;
+
+    if (mgr->client)
+        virNetClientClose(mgr->client);
+    virObjectUnref(mgr->program);
+    virObjectUnref(mgr->client);
+
+    VIR_FREE(mgr);
+}
+
+
+int
+virLogManagerDomainOpenLogFile(virLogManagerPtr mgr,
+                               const char *driver,
+                               const unsigned char *domuuid,
+                               const char *domname,
+                               unsigned int flags,
+                               ino_t *inode,
+                               off_t *offset)
+{
+    struct virLogManagerProtocolDomainOpenLogFileArgs args;
+    struct virLogManagerProtocolDomainOpenLogFileRet ret;
+    int *fdout = NULL;
+    size_t fdoutlen = 0;
+    int rv = -1;
+
+    memset(&args, 0, sizeof(args));
+    memset(&ret, 0, sizeof(ret));
+
+    args.driver = (char *)driver;
+    memcpy(args.dom.uuid, domuuid, VIR_UUID_BUFLEN);
+    args.dom.name = (char *)domname;
+    args.flags = flags;
+
+    if (virNetClientProgramCall(mgr->program,
+                                mgr->client,
+                                mgr->serial++,
+                                VIR_LOG_MANAGER_PROTOCOL_PROC_DOMAIN_OPEN_LOG_FILE,
+                                0, NULL, &fdoutlen, &fdout,
+                                (xdrproc_t)xdr_virLogManagerProtocolDomainOpenLogFileArgs, &args,
+                                (xdrproc_t)xdr_virLogManagerProtocolDomainOpenLogFileRet, &ret) < 0)
+        goto cleanup;
+
+    if (fdoutlen != 1) {
+        if (fdoutlen) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("too many file descriptors received"));
+        } else {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("no file descriptor received"));
+        }
+        goto cleanup;
+    }
+
+    *inode = ret.pos.inode;
+    *offset = ret.pos.offset;
+
+    rv = fdout[0];
+ cleanup:
+    if (rv < 0) {
+        while (fdoutlen)
+            VIR_FORCE_CLOSE(fdout[--fdoutlen]);
+    }
+    VIR_FREE(fdout);
+
+    return rv;
+}
+
+
+int
+virLogManagerDomainGetLogFilePosition(virLogManagerPtr mgr,
+                                      const char *driver,
+                                      const unsigned char *domuuid,
+                                      const char *domname,
+                                      unsigned int flags,
+                                      ino_t *inode,
+                                      off_t *offset)
+{
+    struct virLogManagerProtocolDomainGetLogFilePositionArgs args;
+    struct virLogManagerProtocolDomainGetLogFilePositionRet ret;
+    int rv = -1;
+
+    memset(&args, 0, sizeof(args));
+    memset(&ret, 0, sizeof(ret));
+
+    args.driver = (char *)driver;
+    memcpy(args.dom.uuid, domuuid, VIR_UUID_BUFLEN);
+    args.dom.name = (char *)domname;
+    args.flags = flags;
+
+    if (virNetClientProgramCall(mgr->program,
+                                mgr->client,
+                                mgr->serial++,
+                                VIR_LOG_MANAGER_PROTOCOL_PROC_DOMAIN_GET_LOG_FILE_POSITION,
+                                0, NULL, NULL, NULL,
+                                (xdrproc_t)xdr_virLogManagerProtocolDomainGetLogFilePositionArgs, &args,
+                                (xdrproc_t)xdr_virLogManagerProtocolDomainGetLogFilePositionRet, &ret) < 0)
+        goto cleanup;
+
+    *inode = ret.pos.inode;
+    *offset = ret.pos.offset;
+
+    rv = 0;
+ cleanup:
+    return rv;
+}
+
+
+char *
+virLogManagerDomainReadLogFile(virLogManagerPtr mgr,
+                               const char *driver,
+                               const unsigned char *domuuid,
+                               const char *domname,
+                               ino_t inode,
+                               off_t offset,
+                               size_t maxlen,
+                               unsigned int flags)
+{
+    struct virLogManagerProtocolDomainReadLogFileArgs args;
+    struct virLogManagerProtocolDomainReadLogFileRet ret;
+    int *fdout = NULL;
+    size_t fdoutlen = 0;
+    char *rv = NULL;
+
+    memset(&args, 0, sizeof(args));
+    memset(&ret, 0, sizeof(ret));
+
+    args.driver = (char *)driver;
+    memcpy(args.dom.uuid, domuuid, VIR_UUID_BUFLEN);
+    args.dom.name = (char *)domname;
+    args.flags = flags;
+    args.pos.inode = inode;
+    args.pos.offset = offset;
+    args.maxlen = maxlen;
+
+    if (virNetClientProgramCall(mgr->program,
+                                mgr->client,
+                                mgr->serial++,
+                                VIR_LOG_MANAGER_PROTOCOL_PROC_DOMAIN_READ_LOG_FILE,
+                                0, NULL, &fdoutlen, &fdout,
+                                (xdrproc_t)xdr_virLogManagerProtocolDomainReadLogFileArgs, &args,
+                                (xdrproc_t)xdr_virLogManagerProtocolDomainReadLogFileRet, &ret) < 0)
+        goto cleanup;
+
+    rv = ret.data;
+ cleanup:
+    return rv;
+}

src/logging/log_manager.h

+/*
+ * log_manager.h: log management client
+ *
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library;  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Author: Daniel P. Berrange <berrange@redhat.com>
+ */
+
+
+#ifndef __VIR_LOG_MANAGER_H__
+# define __VIR_LOG_MANAGER_H__
+
+# include "internal.h"
+
+typedef struct _virLogManager virLogManager;
+typedef virLogManager *virLogManagerPtr;
+
+virLogManagerPtr virLogManagerNew(bool privileged);
+
+void virLogManagerFree(virLogManagerPtr mgr);
+
+int virLogManagerDomainOpenLogFile(virLogManagerPtr mgr,
+                                   const char *driver,
+                                   const unsigned char *domuuid,
+                                   const char *domname,
+                                   unsigned int flags,
+                                   ino_t *inode,
+                                   off_t *offset);
+
+int virLogManagerDomainGetLogFilePosition(virLogManagerPtr mgr,
+                                          const char *driver,
+                                          const unsigned char *domuuid,
+                                          const char *domname,
+                                          unsigned int flags,
+                                          ino_t *inode,
+                                          off_t *offset);
+
+char *virLogManagerDomainReadLogFile(virLogManagerPtr mgr,
+                                     const char *driver,
+                                     const unsigned char *domuuid,
+                                     const char *domname,
+                                     ino_t inode,
+                                     off_t offset,
+                                     size_t maxlen,
+                                     unsigned int flags);
+
+#endif /* __VIR_LOG_MANAGER_H__ */