Re: [libvirt] [PATCH 04/10] Add a 'nop' lock driver implementation.

To allow hypervisor drivers to assume that a lock driver impl will be guaranteed to exist, provide a 'nop' impl that is compiled into the library

* src/Makefile.am: Add nop driver * src/locking/lock_driver_nop.c, src/locking/lock_driver_nop.h: Nop lock driver implementation * src/locking/lock_manager.c: Enable direct access of 'nop' driver, instead of dlopen()ing it. --- src/Makefile.am | 4 +- src/locking/lock_driver_nop.c | 115 +++++++++++++++++++++++++++++++++++++++++ src/locking/lock_driver_nop.h | 30 +++++++++++ src/locking/lock_manager.c | 53 ++++++++++--------- 4 files changed, 177 insertions(+), 25 deletions(-) create mode 100644 src/locking/lock_driver_nop.c create mode 100644 src/locking/lock_driver_nop.h diff --git a/src/Makefile.am b/src/Makefile.am index a27838b..96e2edf 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -94,7 +94,9 @@ DRIVER_SOURCES = \ fdstream.c fdstream.h \ $(NODE_INFO_SOURCES) \ libvirt.c libvirt_internal.h \ - locking/lock_manager.c locking/lock_manager.h + locking/lock_manager.c locking/lock_manager.h \ + locking/lock_driver.h \ + locking/lock_driver_nop.h locking/lock_driver_nop.c # XML configuration format handling sources diff --git a/src/locking/lock_driver_nop.c b/src/locking/lock_driver_nop.c new file mode 100644 index 0000000..5ebbd8d --- /dev/null +++ b/src/locking/lock_driver_nop.c @@ -0,0 +1,115 @@ +/* + * lock_driver_nop.c: A lock driver which locks nothing + * + * Copyright (C) 2010-2011 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + *

+ */ + +#include <config.h> + +#include "lock_driver_nop.h" +#include "memory.h" +#include "logging.h" +#include "uuid.h" + + +static int virLockManagerNopInit(unsigned int version, + unsigned int flags) +{ + VIR_DEBUG("version=%u flags=%u", version, flags); + + return 0; +} + +static int virLockManagerNopDeinit(void) +{ + VIR_DEBUG(" "); + + return 0; +} + + +static int virLockManagerNopNew(virLockManagerPtr lock ATTRIBUTE_UNUSED, + unsigned int type ATTRIBUTE_UNUSED, + size_t nparams ATTRIBUTE_UNUSED, + virLockManagerParamPtr params ATTRIBUTE_UNUSED, + unsigned int flags ATTRIBUTE_UNUSED) +{ + return 0; +} + +static int virLockManagerNopAddResource(virLockManagerPtr lock ATTRIBUTE_UNUSED, + unsigned int type ATTRIBUTE_UNUSED, + const char *name ATTRIBUTE_UNUSED, + size_t nparams ATTRIBUTE_UNUSED, + virLockManagerParamPtr params ATTRIBUTE_UNUSED, + unsigned int flags ATTRIBUTE_UNUSED) +{ + + return 0; +} + + +static int virLockManagerNopAcquire(virLockManagerPtr lock ATTRIBUTE_UNUSED, + const char *state ATTRIBUTE_UNUSED, + unsigned int flags ATTRIBUTE_UNUSED) +{ + + return 0; +} + +static int virLockManagerNopRelease(virLockManagerPtr lock ATTRIBUTE_UNUSED, + char **state, + unsigned int flags ATTRIBUTE_UNUSED) +{ + *state = NULL; + + return 0; +} + +static int virLockManagerNopInquire(virLockManagerPtr lock ATTRIBUTE_UNUSED, + char **state, + unsigned int flags ATTRIBUTE_UNUSED) +{ + + *state = NULL; + + return 0; +} + +static void virLockManagerNopFree(virLockManagerPtr lock ATTRIBUTE_UNUSED) +{ +} + +virLockDriver virLockDriverNop = +{ + .version = VIR_LOCK_MANAGER_VERSION, + .flags = 0, + + .drvInit = virLockManagerNopInit, + .drvDeinit = virLockManagerNopDeinit, + + .drvNew = virLockManagerNopNew, + .drvFree = virLockManagerNopFree, + + .drvAddResource = virLockManagerNopAddResource, + + .drvAcquire = virLockManagerNopAcquire, + .drvRelease = virLockManagerNopRelease, + + .drvInquire = virLockManagerNopInquire, +}; diff --git a/src/locking/lock_driver_nop.h b/src/locking/lock_driver_nop.h new file mode 100644 index 0000000..4be5377 --- /dev/null +++ b/src/locking/lock_driver_nop.h @@ -0,0 +1,30 @@ +/* + * lock_driver_nop.h: A lock driver which locks nothing + * + * Copyright (C) 2010-2011 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +#ifndef __VIR_LOCK_DRIVER_NOP_H__ +# define __VIR_LOCK_DRIVER_NOP_H__ + +# include "lock_driver.h" + +extern virLockDriver virLockDriverNop; + + +#endif /* __VIR_LOCK_DRIVER_NOP_H__ */ diff --git a/src/locking/lock_manager.c b/src/locking/lock_manager.c index cb96091..6197fd4 100644 --- a/src/locking/lock_manager.c +++ b/src/locking/lock_manager.c @@ -22,6 +22,7 @@ #include <config.h> #include "lock_manager.h" +#include "lock_driver_nop.h" #include "virterror_internal.h" #include "logging.h" #include "util.h" @@ -123,35 +124,39 @@ virLockManagerPluginPtr virLockManagerPluginNew(const char *name, const char *moddir = getenv("LIBVIRT_LOCK_MANAGER_PLUGIN_DIR"); char *modfile = NULL; - if (moddir == NULL) - moddir = DEFAULT_LOCK_MANAGER_PLUGIN_DIR; + if (STREQ(name, "nop")) { + driver = &virLockDriverNop; + } else { + if (moddir == NULL) + moddir = DEFAULT_LOCK_MANAGER_PLUGIN_DIR; - VIR_DEBUG("Module load %s from %s", name, moddir); + VIR_DEBUG("Module load %s from %s", name, moddir); - if (virAsprintf(&modfile, "%s/%s.so", moddir, name) < 0) { - virReportOOMError(); - return NULL; - } + if (virAsprintf(&modfile, "%s/%s.so", moddir, name) < 0) { + virReportOOMError(); + return NULL; + } - if (access(modfile, R_OK) < 0) { - virReportSystemError(errno, - _("Plugin %s not accessible"), - modfile); - goto cleanup; - } + if (access(modfile, R_OK) < 0) { + virReportSystemError(errno, + _("Plugin %s not accessible"), + modfile); + goto cleanup; + } - handle = dlopen(modfile, RTLD_NOW | RTLD_LOCAL); - if (!handle) { - virLockError(VIR_ERR_SYSTEM_ERROR, - _("Failed to load plugin %s: %s"), - modfile, dlerror()); - goto cleanup; - } + handle = dlopen(modfile, RTLD_NOW | RTLD_LOCAL); + if (!handle) { + virLockError(VIR_ERR_SYSTEM_ERROR, + _("Failed to load plugin %s: %s"), + modfile, dlerror()); + goto cleanup; + } - if (!(driver = dlsym(handle, "virLockDriverImpl"))) { - virLockError(VIR_ERR_INTERNAL_ERROR, "%s", - _("Missing plugin initialization symbol 'virLockDriverImpl'")); - goto cleanup; + if (!(driver = dlsym(handle, "virLockDriverImpl"))) { + virLockError(VIR_ERR_INTERNAL_ERROR, "%s", + _("Missing plugin initialization symbol 'virLockDriverImpl'")); + goto cleanup; + } } if (driver->drvInit(VIR_LOCK_MANAGER_VERSION, flags) < 0) {