[libvirt] [PATCH 8/8] Start of a lock manager daemon
Daniel P. Berrange
berrange at redhat.com
Wed Dec 1 17:26:34 UTC 2010
This starts the basic framework for a lock manager daemon to
provide guarenteed isolation between VMs using disk images.
It is a simple demo of how the generic RPC server APIs are
to be used
---
src/Makefile.am | 16 ++
src/virtlockd.c | 620 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 636 insertions(+), 0 deletions(-)
create mode 100644 src/virtlockd.c
diff --git a/src/Makefile.am b/src/Makefile.am
index 8986f22..4c9cc79 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1167,6 +1167,22 @@ libvirt_net_client_la_LDFLAGS = \
libvirt_net_client_la_LIBADD = \
$(CYGWIN_EXTRA_LIBADD)
+sbin_PROGRAMS = virtlockd
+
+virtlockd_SOURCES = virtlockd.c
+virtlockd_CFLAGS = \
+ $(AM_CFLAGS)
+virtlockd_LDFLAGS = \
+ $(AM_LDFLAGS) \
+ $(CYGWIN_EXTRA_LDFLAGS) \
+ $(MINGW_EXTRA_LDFLAGS)
+virtlockd_LDADD = \
+ ../gnulib/lib/libgnu.la \
+ libvirt-net-server.la \
+ libvirt-net-rpc.la \
+ libvirt_util.la \
+ $(CYGWIN_EXTRA_LIBADD)
+
libexec_PROGRAMS =
if WITH_STORAGE_DISK
diff --git a/src/virtlockd.c b/src/virtlockd.c
new file mode 100644
index 0000000..ec7dd5d
--- /dev/null
+++ b/src/virtlockd.c
@@ -0,0 +1,620 @@
+/*
+ * virtlockd.c: lock management daemon
+ *
+ * Copyright (C) 2006-2010 Red Hat, Inc.
+ * Copyright (C) 2006 Daniel P. Berrange
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author: Daniel P. Berrange <berrange at redhat.com>
+ */
+
+#include <config.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <getopt.h>
+#include <stdlib.h>
+
+
+#include "util.h"
+#include "files.h"
+#include "virterror_internal.h"
+#include "logging.h"
+#include "memory.h"
+#include "conf.h"
+#include "rpc/virnetserver.h"
+#include "threads.h"
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+#include "configmake.h"
+
+enum {
+ VIR_DAEMON_ERR_NONE = 0,
+ VIR_DAEMON_ERR_PIDFILE,
+ VIR_DAEMON_ERR_RUNDIR,
+ VIR_DAEMON_ERR_INIT,
+ VIR_DAEMON_ERR_SIGNAL,
+ VIR_DAEMON_ERR_PRIVS,
+ VIR_DAEMON_ERR_NETWORK,
+ VIR_DAEMON_ERR_CONFIG,
+ VIR_DAEMON_ERR_HOOKS,
+
+ VIR_DAEMON_ERR_LAST
+};
+
+VIR_ENUM_DECL(virDaemonErr)
+VIR_ENUM_IMPL(virDaemonErr, VIR_DAEMON_ERR_LAST,
+ "Initialization successful",
+ "Unable to obtain pidfile",
+ "Unable to create rundir",
+ "Unable to initialize libvirt",
+ "Unable to setup signal handlers",
+ "Unable to drop privileges",
+ "Unable to initialize network sockets",
+ "Unable to load configuration file",
+ "Unable to look for hook scripts");
+
+
+static int daemonForkIntoBackground(const char *argv0)
+{
+ int statuspipe[2];
+ if (pipe(statuspipe) < 0)
+ return -1;
+
+ int pid = fork();
+ switch (pid) {
+ case 0:
+ {
+ int stdinfd = -1;
+ int stdoutfd = -1;
+ int nextpid;
+
+ VIR_FORCE_CLOSE(statuspipe[0]);
+
+ if ((stdinfd = open("/dev/null", O_RDONLY)) < 0)
+ goto cleanup;
+ if ((stdoutfd = open("/dev/null", O_WRONLY)) < 0)
+ goto cleanup;
+ if (dup2(stdinfd, STDIN_FILENO) != STDIN_FILENO)
+ goto cleanup;
+ if (dup2(stdoutfd, STDOUT_FILENO) != STDOUT_FILENO)
+ goto cleanup;
+ if (dup2(stdoutfd, STDERR_FILENO) != STDERR_FILENO)
+ goto cleanup;
+ if (VIR_CLOSE(stdinfd) < 0)
+ goto cleanup;
+ if (VIR_CLOSE(stdoutfd) < 0)
+ goto cleanup;
+
+ if (setsid() < 0)
+ goto cleanup;
+
+ nextpid = fork();
+ switch (nextpid) {
+ case 0:
+ return statuspipe[1];
+ case -1:
+ return -1;
+ default:
+ _exit(0);
+ }
+
+ cleanup:
+ VIR_FORCE_CLOSE(stdoutfd);
+ VIR_FORCE_CLOSE(stdinfd);
+ return -1;
+
+ }
+
+ case -1:
+ return -1;
+
+ default:
+ {
+ int got, exitstatus = 0;
+ int ret;
+ char status;
+
+ VIR_FORCE_CLOSE(statuspipe[1]);
+
+ /* We wait to make sure the first child forked successfully */
+ if ((got = waitpid(pid, &exitstatus, 0)) < 0 ||
+ got != pid ||
+ exitstatus != 0) {
+ return -1;
+ }
+
+ /* Now block until the second child initializes successfully */
+ again:
+ ret = read(statuspipe[0], &status, 1);
+ if (ret == -1 && errno == EINTR)
+ goto again;
+
+ if (ret == 1 && status != 0) {
+ fprintf(stderr,
+ _("%s: error: %s. Check /var/log/messages or run without "
+ "--daemon for more info.\n"), argv0,
+ virDaemonErrTypeToString(status));
+ }
+ _exit(ret == 1 && status == 0 ? 0 : 1);
+ }
+ }
+}
+
+static int daemonWritePidFile(const char *argv0, const char *pidFile) {
+ int fd;
+ FILE *fh;
+ char ebuf[1024];
+
+ if (pidFile[0] == '\0')
+ return 0;
+
+ if ((fd = open(pidFile, O_WRONLY|O_CREAT|O_EXCL, 0644)) < 0) {
+ VIR_ERROR(_("Failed to open pid file '%s' : %s"),
+ pidFile, virStrerror(errno, ebuf, sizeof ebuf));
+ return -1;
+ }
+
+ if (!(fh = VIR_FDOPEN(fd, "w"))) {
+ VIR_ERROR(_("Failed to fdopen pid file '%s' : %s"),
+ pidFile, virStrerror(errno, ebuf, sizeof ebuf));
+ VIR_FORCE_CLOSE(fd);
+ return -1;
+ }
+
+ if (fprintf(fh, "%lu\n", (unsigned long)getpid()) < 0) {
+ VIR_ERROR(_("%s: Failed to write to pid file '%s' : %s"),
+ argv0, pidFile, virStrerror(errno, ebuf, sizeof ebuf));
+ VIR_FORCE_FCLOSE(fh);
+ return -1;
+ }
+
+ if (VIR_FCLOSE(fh) == EOF) {
+ VIR_ERROR(_("%s: Failed to close pid file '%s' : %s"),
+ argv0, pidFile, virStrerror(errno, ebuf, sizeof ebuf));
+ return -1;
+ }
+
+ return 0;
+}
+
+
+static int daemonMakePaths(char **statedir,
+ char **pidfile,
+ char **sockfile)
+{
+ char *userdir = NULL;
+ uid_t uid = geteuid();
+
+ if (uid == 0) {
+ if (!(*statedir = strdup(LOCALSTATEDIR "/run")))
+ goto no_memory;
+ if (!(*pidfile = strdup(LOCALSTATEDIR "/run/virtlockd.pid")))
+ goto no_memory;
+ if (!(*sockfile = strdup(LOCALSTATEDIR "/run/virtlockd.sock")))
+ goto no_memory;
+ } else {
+ if (!(userdir = virGetUserDirectory(uid)))
+ goto error;
+
+ if (virAsprintf(statedir, "%s/.libvirt", userdir) < 0)
+ goto no_memory;
+ if (virAsprintf(pidfile, "%s/.libvirt/virtlockd.pid", userdir) < 0)
+ goto no_memory;
+ if (virAsprintf(sockfile, "%s/.libvirt/virtlockd.sock", userdir) < 0)
+ goto no_memory;
+ }
+ VIR_FREE(userdir);
+ return 0;
+
+no_memory:
+ VIR_FREE(*pidfile);
+ VIR_FREE(*sockfile);
+error:
+ VIR_FREE(userdir);
+ return -1;
+}
+
+static void daemonErrorHandler(void *opaque ATTRIBUTE_UNUSED,
+ virErrorPtr err ATTRIBUTE_UNUSED)
+{
+ /* Don't do anything, since logging infrastructure already
+ * took care of reporting the error */
+}
+
+
+/*
+ * Set up the logging environment
+ * By default if daemonized all errors go to syslog and the logging
+ * is also saved onto the logfile libvird.log, but if verbose or error
+ * debugging is asked for then output informations or debug.
+ */
+static int
+daemonSetLogging(virConfPtr conf ATTRIBUTE_UNUSED,
+ const char *filename ATTRIBUTE_UNUSED,
+ int godaemon, int verbose)
+{
+ //int log_level = 0;
+ char *log_filters = NULL;
+ char *log_outputs = NULL;
+ int ret = -1;
+
+ virLogReset();
+#if 0
+ /*
+ * Libvirtd's order of precedence is:
+ * cmdline > environment > config
+ *
+ * In order to achieve this, we must process configuration in
+ * different order for the log level versus the filters and
+ * outputs. Because filters and outputs append, we have to look at
+ * the environment first and then only check the config file if
+ * there was no result from the environment. The default output is
+ * then applied only if there was no setting from either of the
+ * first two. Because we don't have a way to determine if the log
+ * level has been set, we must process variables in the opposite
+ * order, each one overriding the previous.
+ */
+ GET_CONF_INT (conf, filename, log_level);
+ if (log_level != 0)
+ virLogSetDefaultPriority(log_level);
+
+ if (virLogGetNbFilters() == 0) {
+ GET_CONF_STR (conf, filename, log_filters);
+ virLogParseFilters(log_filters);
+ }
+
+ if (virLogGetNbOutputs() == 0) {
+ GET_CONF_STR (conf, filename, log_outputs);
+ virLogParseOutputs(log_outputs);
+ }
+#endif
+
+ virLogSetFromEnv();
+
+ /*
+ * If no defined outputs, then direct to syslog when running
+ * as daemon. Otherwise the default output is stderr.
+ */
+ if (virLogGetNbOutputs() == 0) {
+ char *tmp = NULL;
+ if (godaemon) {
+ if (virAsprintf (&tmp, "%d:syslog:libvirtd",
+ virLogGetDefaultPriority()) < 0)
+ goto free_and_fail;
+ } else {
+ if (virAsprintf (&tmp, "%d:stderr",
+ virLogGetDefaultPriority()) < 0)
+ goto free_and_fail;
+ }
+ virLogParseOutputs(tmp);
+ VIR_FREE(tmp);
+ }
+
+ /*
+ * Command line override for --verbose
+ */
+ if ((verbose) && (virLogGetDefaultPriority() > VIR_LOG_INFO))
+ virLogSetDefaultPriority(VIR_LOG_INFO);
+
+ ret = 0;
+
+free_and_fail:
+ VIR_FREE(log_filters);
+ VIR_FREE(log_outputs);
+ return(ret);
+}
+
+/* Read the config file if it exists.
+ * Only used in the remote case, hence the name.
+ */
+static int daemonReadConfigFile(const char *filename,
+ int godaemon, int verbose)
+{
+ virConfPtr conf;
+
+ if (!(conf = virConfReadFile (filename, 0)))
+ goto error;
+
+ if (daemonSetLogging(conf, filename, godaemon, verbose) < 0)
+ goto error;
+
+ virConfFree (conf);
+ return 0;
+
+error:
+ virConfFree (conf);
+
+ return -1;
+}
+
+/* Display version information. */
+static void daemonVersion(const char *argv0)
+{
+ printf ("%s (%s) %s\n", argv0, PACKAGE_NAME, PACKAGE_VERSION);
+}
+
+static void daemonShutdownHandler(virNetServerPtr srv,
+ siginfo_t *sig ATTRIBUTE_UNUSED,
+ void *opaque ATTRIBUTE_UNUSED)
+{
+ virNetServerQuit(srv);
+}
+
+static int daemonSetupSignals(virNetServerPtr srv)
+{
+ if (virNetServerAddSignalHandler(srv, SIGINT, daemonShutdownHandler, NULL) < 0)
+ return -1;
+ if (virNetServerAddSignalHandler(srv, SIGQUIT, daemonShutdownHandler, NULL) < 0)
+ return -1;
+ if (virNetServerAddSignalHandler(srv, SIGTERM, daemonShutdownHandler, NULL) < 0)
+ return -1;
+ return 0;
+}
+
+static int daemonSetupNetworking(virNetServerPtr srv, const char *sock_path)
+{
+ virNetServerServicePtr svc;
+
+ if (!(svc = virNetServerServiceNewUNIX(sock_path, 0700, 0, 0, false)))
+ return -1;
+
+ if (virNetServerAddService(srv, svc) < 0) {
+ virNetServerServiceFree(svc);
+ return -1;
+ }
+ return 0;
+}
+
+
+static void daemonUsage(const char *argv0)
+{
+ fprintf (stderr,
+ _("\n\
+Usage:\n\
+ %s [options]\n\
+\n\
+Options:\n\
+ -v | --verbose Verbose messages.\n\
+ -d | --daemon Run as a daemon & write PID file.\n\
+ -t | --timeout <secs> Exit after timeout period.\n\
+ -f | --config <file> Configuration file.\n\
+ | --version Display version information.\n\
+ -p | --pid-file <file> Change name of PID file.\n\
+\n\
+libvirt lock management daemon:\n\
+\n\
+ Default paths:\n\
+\n\
+ Configuration file (unless overridden by -f):\n\
+ %s/libvirt/libvirtd.conf\n\
+\n\
+ Sockets (as root):\n\
+ %s/run/virtlockd.sock\n\
+\n\
+ Sockets (as non-root):\n\
+ $HOME/.libvirt/virtlockd.sock (in UNIX abstract namespace)\n\
+\n\
+ Default PID file (as root):\
+ %s/run/virtlockd.pid\n\
+\n\
+ Default PID file (as non-root):\
+ $HOME/.libvirt/virtlockd.pid\n\
+\n"),
+ argv0,
+ SYSCONFDIR,
+ LOCALSTATEDIR,
+ LOCALSTATEDIR);
+}
+
+enum {
+ OPT_VERSION = 129
+};
+
+#define MAX_LISTEN 5
+int main(int argc, char **argv) {
+ virNetServerPtr srv = NULL;
+ const char *remote_config_file = NULL;
+ int statuswrite = -1;
+ int ret = 1;
+ int verbose = 0;
+ int godaemon = 0;
+ int timeout = 0;
+ char *state_dir = NULL;
+ char *pid_file = NULL;
+ char *sock_file = NULL;
+
+ struct option opts[] = {
+ { "verbose", no_argument, &verbose, 1},
+ { "daemon", no_argument, &godaemon, 1},
+ { "config", required_argument, NULL, 'f'},
+ { "timeout", required_argument, NULL, 't'},
+ { "pid-file", required_argument, NULL, 'p'},
+ { "version", no_argument, NULL, OPT_VERSION },
+ { "help", no_argument, NULL, '?' },
+ {0, 0, 0, 0}
+ };
+
+ if (setlocale (LC_ALL, "") == NULL ||
+ bindtextdomain (PACKAGE, LOCALEDIR) == NULL ||
+ textdomain(PACKAGE) == NULL ||
+ virThreadInitialize() < 0 ||
+ virErrorInitialize() < 0 ||
+ virRandomInitialize(time(NULL) ^ getpid())) {
+ fprintf(stderr, _("%s: initialization failed\n"), argv[0]);
+ exit(EXIT_FAILURE);
+ }
+
+ if (daemonMakePaths(&state_dir, &pid_file, &sock_file) < 0)
+ exit(EXIT_FAILURE);
+
+ while (1) {
+ int optidx = 0;
+ int c;
+ char *tmp;
+
+ c = getopt_long(argc, argv, "ldf:p:t:v", opts, &optidx);
+
+ if (c == -1) {
+ break;
+ }
+
+ switch (c) {
+ case 0:
+ /* Got one of the flags */
+ break;
+ case 'v':
+ verbose = 1;
+ break;
+ case 'd':
+ godaemon = 1;
+ break;
+
+ case 't':
+ if (virStrToLong_i(optarg, &tmp, 10, &timeout) != 0
+ || timeout <= 0
+ /* Ensure that we can multiply by 1000 without overflowing. */
+ || timeout > INT_MAX / 1000)
+ timeout = -1;
+ break;
+
+ case 'p':
+ VIR_FREE(pid_file);
+ if (!(pid_file = strdup(optarg)))
+ exit(EXIT_FAILURE);
+ break;
+
+ case 'f':
+ remote_config_file = optarg;
+ break;
+
+ case OPT_VERSION:
+ daemonVersion(argv[0]);
+ return 0;
+
+ case '?':
+ daemonUsage(argv[0]);
+ return 2;
+
+ default:
+ fprintf (stderr, _("%s: internal error: unknown flag: %c\n"),
+ argv[0], c);
+ exit (EXIT_FAILURE);
+ }
+ }
+
+ if (remote_config_file == NULL) {
+ static const char *default_config_file
+ = SYSCONFDIR "/libvirt/libvirtd.conf";
+ remote_config_file =
+ (access(default_config_file, R_OK) == 0
+ ? default_config_file
+ : "/dev/null");
+ }
+
+ if (godaemon) {
+ char ebuf[1024];
+ if ((statuswrite = daemonForkIntoBackground(argv[0])) < 0) {
+ VIR_ERROR(_("Failed to fork as daemon: %s"),
+ virStrerror(errno, ebuf, sizeof ebuf));
+ goto cleanup;
+ }
+ }
+
+ if (!(srv = virNetServerNew(1, 1, 20))) {
+ ret = VIR_DAEMON_ERR_INIT;
+ goto cleanup;
+ }
+
+ if ((daemonSetupSignals(srv)) < 0) {
+ ret = VIR_DAEMON_ERR_SIGNAL;
+ goto cleanup;
+ }
+
+ /* If we have a pidfile set, claim it now, exiting if already taken */
+ if (daemonWritePidFile(argv[0], pid_file) < 0) {
+ pid_file = NULL; /* Prevent unlinking of someone else's pid ! */
+ ret = VIR_DAEMON_ERR_PIDFILE;
+ goto cleanup;
+ }
+
+ /* Ensure the rundir exists (on tmpfs on some systems) */
+ if (mkdir(state_dir, 0755)) {
+ if (errno != EEXIST) {
+ char ebuf[1024];
+ VIR_ERROR(_("unable to create rundir %s: %s"), state_dir,
+ virStrerror(errno, ebuf, sizeof(ebuf)));
+ ret = VIR_DAEMON_ERR_RUNDIR;
+ goto cleanup;
+ }
+ }
+
+ /* Read the config file (if it exists). */
+ if (daemonReadConfigFile(remote_config_file, godaemon, verbose) < 0) {
+ ret = VIR_DAEMON_ERR_CONFIG;
+ goto cleanup;
+ }
+
+ if (daemonSetupNetworking(srv, sock_file) < 0) {
+ ret = VIR_DAEMON_ERR_NETWORK;
+ goto cleanup;
+ }
+
+ /* Disable error func, now logging is setup */
+ virSetErrorFunc(NULL, daemonErrorHandler);
+
+
+ /* Tell parent of daemon that basic initialization is complete
+ * In particular we're ready to accept net connections & have
+ * written the pidfile
+ */
+ if (statuswrite != -1) {
+ char status = 0;
+ while (write(statuswrite, &status, 1) == -1 &&
+ errno == EINTR)
+ ;
+ VIR_FORCE_CLOSE(statuswrite);
+ }
+
+ /* Start accepting new clients from network */
+
+ virNetServerUpdateServices(srv, true);
+ virNetServerRun(srv);
+ ret = 0;
+
+cleanup:
+ virNetServerFree(srv);
+ if (statuswrite != -1) {
+ if (ret != 0) {
+ /* Tell parent of daemon what failed */
+ char status = ret;
+ while (write(statuswrite, &status, 1) == -1 &&
+ errno == EINTR)
+ ;
+ }
+ VIR_FORCE_CLOSE(statuswrite);
+ }
+ if (pid_file)
+ unlink(pid_file);
+ virLogShutdown();
+ VIR_FREE(pid_file);
+ VIR_FREE(sock_file);
+ VIR_FREE(state_dir);
+ return ret;
+}
--
1.7.2.3
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