[libvirt] [PATCH] [3/6] Add hook utilities
Daniel Veillard
veillard at redhat.com
Fri Mar 26 15:43:41 UTC 2010
Add hook utilities
This exports 3 basic routines:
- virHookInitialize() initializing the hook support by looking for
scripts availability
- virHookPresent() used to test if there is a hook for a given driver
- virHookCall() which actually calls a synchronous script hook with
the needed parameters
Note that this doesn't expose any public API except for the locations
and arguments passed to the scripts
* src/Makefile.am: add the 2 new files
* src/util/hooks.h src/util/hooks.c: implements the 3 functions
* src/libvirt_private.syms: export the 3 symbols internally
diff --git a/src/Makefile.am b/src/Makefile.am
index 5f6b325..8f1e549 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -54,6 +54,7 @@ UTIL_SOURCES = \
util/cgroup.c util/cgroup.h \
util/event.c util/event.h \
util/hash.c util/hash.h \
+ util/hooks.c util/hooks.h \
util/iptables.c util/iptables.h \
util/ebtables.c util/ebtables.h \
util/json.c util/json.h \
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index d9aff54..4e4f126 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -242,6 +242,12 @@ virHashSearch;
virHashSize;
+# hooks.h
+virHookCall;
+virHookInitialize;
+virHookPresent;
+
+
# interface_conf.h
virInterfaceDefFormat;
virInterfaceDefParseFile;
diff --git a/src/util/hooks.c b/src/util/hooks.c
new file mode 100644
index 0000000..3c027d6
--- /dev/null
+++ b/src/util/hooks.c
@@ -0,0 +1,439 @@
+/*
+ * hooks.c: implementation of the synchronous hooks support
+ *
+ * Copyright (C) 2010 Red Hat, Inc.
+ * Copyright (C) 2010 Daniel Veillard
+ *
+ * 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 Veillard <veillard at redhat.com>
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "virterror_internal.h"
+#include "hooks.h"
+#include "util.h"
+#include "conf/domain_conf.h"
+#include "logging.h"
+#include "memory.h"
+
+#define VIR_FROM_THIS VIR_FROM_HOOK
+
+#define virHookReportError(code, ...) \
+ virReportErrorHelper(NULL, VIR_FROM_HOOK, code, __FILE__, \
+ __FUNCTION__, __LINE__, __VA_ARGS__)
+
+#define LIBVIRT_HOOK_DIR SYSCONF_DIR "/libvirt/hooks"
+
+VIR_ENUM_DECL(virHookDriver)
+VIR_ENUM_DECL(virHookDaemonOp)
+VIR_ENUM_DECL(virHookSubop)
+VIR_ENUM_DECL(virHookQemuOp)
+VIR_ENUM_DECL(virHookLxcOp)
+
+VIR_ENUM_IMPL(virHookDriver,
+ VIR_HOOK_DRIVER_LAST,
+ "daemon",
+ "qemu",
+ "lxc")
+
+VIR_ENUM_IMPL(virHookDaemonOp, VIR_HOOK_DAEMON_OP_LAST,
+ "start",
+ "shutdown",
+ "reload")
+
+VIR_ENUM_IMPL(virHookSubop, VIR_HOOK_SUBOP_LAST,
+ "-",
+ "begin",
+ "end")
+
+VIR_ENUM_IMPL(virHookQemuOp, VIR_HOOK_QEMU_OP_LAST,
+ "start",
+ "stopped")
+
+VIR_ENUM_IMPL(virHookLxcOp, VIR_HOOK_QEMU_OP_LAST,
+ "start",
+ "stopped")
+
+static int virHooksFound = -1;
+
+/**
+ * virHookCheck:
+ * @driver: the driver name "daemon", "qemu", "lxc"...
+ *
+ * Check is there is an installed hook for the given driver, if this
+ * is the case register it. Then subsequent calls to virHookCall
+ * will call the hook if found.
+ *
+ * Returns 1 if found, 0 if not found, and -1 in case of error
+ */
+static int
+virHookCheck(int no, const char *driver) {
+ char *path;
+ struct stat sb;
+ int ret;
+
+ if (driver == NULL) {
+ virHookReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Invalid hook name for #%d"), no);
+ return(-1);
+ }
+
+ ret = virBuildPath(&path, LIBVIRT_HOOK_DIR, driver);
+ if ((ret < 0) || (path == NULL)) {
+ virHookReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Failed to build path for %s hook"),
+ driver);
+ return(-1);
+ }
+
+ if (stat(path, &sb) < 0) {
+ ret = 0;
+ VIR_DEBUG("No hook script %s", path);
+ } else {
+ if (access(path, X_OK) != 0) {
+ ret = 0;
+ VIR_WARN("Non executable hook script %s", path);
+ } else {
+ ret = 1;
+ VIR_DEBUG("Found hook script %s", path);
+ }
+ }
+
+ VIR_FREE(path);
+ return(ret);
+}
+
+/*
+ * virHookInitialize:
+ *
+ * Initialize syncronous hooks support.
+ * Check is there is an installed hook for all the drivers
+ *
+ * Returns the number of hooks found or -1 in case of failure
+ */
+int
+virHookInitialize(void) {
+ int i, res, ret = 0;
+
+ virHooksFound = 0;
+ for (i = 0;i < VIR_HOOK_DRIVER_LAST;i++) {
+ res = virHookCheck(i, virHookDriverTypeToString(i));
+ if (res < 0)
+ return(-1);
+
+ if (res == 1) {
+ virHooksFound |= (1 << i);
+ ret++;
+ }
+ }
+ return(ret);
+}
+
+/**
+ * virHookPresent:
+ * @driver: the driver number (from virHookDriver enum)
+ *
+ * Check if a hook exists for the given driver, this is needed
+ * to avoid unecessary work if the hook is not present
+ *
+ * Returns 1 if present, 0 otherwise
+ */
+int
+virHookPresent(int driver) {
+ if ((driver < VIR_HOOK_DRIVER_DAEMON) ||
+ (driver >= VIR_HOOK_DRIVER_LAST))
+ return(0);
+ if (virHooksFound == -1)
+ return(0);
+
+ if ((virHooksFound & (1 << driver)) == 0)
+ return(0);
+ return(1);
+}
+
+/*
+ * virHookCall:
+ * @driver: the driver number (from virHookDriver enum)
+ * @id: an id for the object '-' if non available for example on daemon hooks
+ * @op: the operation on the id e.g. VIR_HOOK_QEMU_OP_START
+ * @sub_op: a sub_operation, currently unused
+ * @extra: optional string informations
+ * @input: extra input given to the script on stdin
+ *
+ * Implement an Hook call, where the external script for the driver is
+ * called with the given informations. This is a synchronous call, we wait for
+ * execution completion
+ *
+ * Returns: 0 if the execution suceeded, 1 if the script was not found or
+ * invalid parameters, and -1 if script returned an error
+ */
+int
+virHookCall(int driver, const char *id, int op, int sub_op, const char *extra,
+ const char *input) {
+ int ret, waitret, exitstatus, i;
+ char *path;
+ int argc = 0, arga = 0;
+ const char **argv = NULL;
+ int envc = 0, enva = 0;
+ const char **env = NULL;
+ const char *drvstr;
+ const char *opstr;
+ const char *subopstr;
+ pid_t pid;
+ int outfd = -1, errfd = -1;
+ int pipefd[2] = { -1, -1};
+ char *outbuf = NULL;
+ char *errbuf = NULL;
+
+ if ((driver < VIR_HOOK_DRIVER_DAEMON) ||
+ (driver >= VIR_HOOK_DRIVER_LAST))
+ return(1);
+
+ /*
+ * We cache the availability of the script to minimize impact at
+ * runtime if no script is defined, this is being reset on SIGUP
+ */
+ if ((virHooksFound == -1) ||
+ ((driver == VIR_HOOK_DRIVER_DAEMON) &&
+ (op == VIR_HOOK_DAEMON_OP_RELOAD)))
+ virHookInitialize();
+
+ if ((virHooksFound & (1 << driver)) == 0)
+ return(1);
+
+ drvstr = virHookDriverTypeToString(driver);
+
+ opstr = NULL;
+ switch (driver) {
+ case VIR_HOOK_DRIVER_DAEMON:
+ opstr = virHookDaemonOpTypeToString(op);
+ break;
+ case VIR_HOOK_DRIVER_QEMU:
+ opstr = virHookQemuOpTypeToString(op);
+ break;
+ case VIR_HOOK_DRIVER_LXC:
+ opstr = virHookLxcOpTypeToString(op);
+ break;
+ }
+ if (opstr == NULL) {
+ virHookReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Hook for %s, failed to find operation #%d"),
+ drvstr, op);
+ return(1);
+ }
+ subopstr = virHookSubopTypeToString(sub_op);
+ if (subopstr == NULL)
+ subopstr = "-";
+ if (extra == NULL)
+ extra = "-";
+
+ ret = virBuildPath(&path, LIBVIRT_HOOK_DIR, drvstr);
+ if ((ret < 0) || (path == NULL)) {
+ virHookReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Failed to build path for %s hook"),
+ drvstr);
+ return(-1);
+ }
+
+ /*
+ * Convenience macros borrowed from qemudBuildCommandLine()
+ */
+#define ADD_ARG_SPACE \
+ do { \
+ if (argc == arga) { \
+ arga += 10; \
+ if (VIR_REALLOC_N(argv, arga) < 0) \
+ goto no_memory; \
+ } \
+ } while (0)
+
+#define ADD_ARG(thisarg) \
+ do { \
+ ADD_ARG_SPACE; \
+ argv[argc++] = thisarg; \
+ } while (0)
+
+#define ADD_ARG_LIT(thisarg) \
+ do { \
+ ADD_ARG_SPACE; \
+ if ((argv[argc++] = strdup(thisarg)) == NULL) \
+ goto no_memory; \
+ } while (0)
+
+#define ADD_ENV_SPACE \
+ do { \
+ if (envc == enva) { \
+ enva += 10; \
+ if (VIR_REALLOC_N(env, enva) < 0) \
+ goto no_memory; \
+ } \
+ } while (0)
+
+#define ADD_ENV(thisarg) \
+ do { \
+ ADD_ENV_SPACE; \
+ env[envc++] = thisarg; \
+ } while (0)
+
+#define ADD_ENV_LIT(thisarg) \
+ do { \
+ ADD_ENV_SPACE; \
+ if ((env[envc++] = strdup(thisarg)) == NULL) \
+ goto no_memory; \
+ } while (0)
+
+#define ADD_ENV_PAIR(envname, val) \
+ do { \
+ char *envval; \
+ ADD_ENV_SPACE; \
+ if (virAsprintf(&envval, "%s=%s", envname, val) < 0) \
+ goto no_memory; \
+ env[envc++] = envval; \
+ } while (0)
+
+#define ADD_ENV_COPY(envname) \
+ do { \
+ char *val = getenv(envname); \
+ if (val != NULL) { \
+ ADD_ENV_PAIR(envname, val); \
+ } \
+ } while (0)
+
+ ADD_ENV_LIT("LC_ALL=C");
+
+ ADD_ENV_COPY("LD_PRELOAD");
+ ADD_ENV_COPY("LD_LIBRARY_PATH");
+ ADD_ENV_COPY("PATH");
+ ADD_ENV_COPY("HOME");
+ ADD_ENV_COPY("USER");
+ ADD_ENV_COPY("LOGNAME");
+ ADD_ENV_COPY("TMPDIR");
+ ADD_ENV(NULL);
+
+ ADD_ARG_LIT(path);
+ ADD_ARG_LIT(id);
+ ADD_ARG_LIT(opstr);
+ ADD_ARG_LIT(subopstr);
+
+ ADD_ARG_LIT(extra);
+ ADD_ARG(NULL);
+
+ /* pass any optional input on the script stdin */
+ if (input != NULL) {
+ if (pipe(pipefd) < -1) {
+ virReportSystemError(errno, "%s",
+ _("unable to create pipe for hook input"));
+ ret = 1;
+ goto cleanup;
+ }
+ if (safewrite(pipefd[1], input, strlen(input)) < 0) {
+ virReportSystemError(errno, "%s",
+ _("unable to write to pipe for hook input"));
+ ret = 1;
+ goto cleanup;
+ }
+ ret = virExec(argv, env, NULL, &pid, pipefd[0], &outfd, &errfd,
+ VIR_EXEC_NONE | VIR_EXEC_NONBLOCK);
+ close(pipefd[1]);
+ pipefd[1] = -1;
+ } else {
+ ret = virExec(argv, env, NULL, &pid, -1, &outfd, &errfd,
+ VIR_EXEC_NONE | VIR_EXEC_NONBLOCK);
+ }
+ if (ret < 0) {
+ virHookReportError(VIR_ERR_HOOK_SCRIPT_FAILED,
+ _("Failed to execute %s hook script"),
+ path);
+ ret = 1;
+ goto cleanup;
+ }
+
+ /*
+ * we are interested in the error log if any and make sure the
+ * script doesn't block on stdout/stderr descriptors being full
+ * stdout can be useful for debug too.
+ */
+ if (virPipeReadUntilEOF(outfd, errfd, &outbuf, &errbuf) < 0) {
+ virReportSystemError(errno, _("cannot wait for '%s'"), path);
+ while (waitpid(pid, &exitstatus, 0) == -1 && errno == EINTR)
+ ;
+ ret = 1;
+ goto cleanup;
+ }
+
+ if (outbuf)
+ VIR_DEBUG("Command stdout: %s", outbuf);
+ if (errbuf)
+ VIR_DEBUG("Command stderr: %s", errbuf);
+
+ while ((waitret = waitpid(pid, &exitstatus, 0) == -1) &&
+ (errno == EINTR));
+ if (waitret == -1) {
+ virReportSystemError(errno, _("Failed to wait for '%s'"), path);
+ ret = 1;
+ goto cleanup;
+ }
+ if (exitstatus != 0) {
+ virHookReportError(VIR_ERR_HOOK_SCRIPT_FAILED,
+ _("Hook script %s %s failed with error code %d:%s"),
+ path, drvstr, exitstatus, errbuf);
+ ret = -1;
+ }
+
+cleanup:
+ if (pipefd[0] > 0)
+ close(pipefd[0]);
+ if (pipefd[1] > 0)
+ close(pipefd[1]);
+ if (argv) {
+ for (i = 0 ; i < argc ; i++)
+ VIR_FREE((argv)[i]);
+ VIR_FREE(argv);
+ }
+ if (env) {
+ for (i = 0 ; i < envc ; i++)
+ VIR_FREE((env)[i]);
+ VIR_FREE(env);
+ }
+ VIR_FREE(outbuf);
+ VIR_FREE(errbuf);
+ VIR_FREE(path);
+
+ return(ret);
+
+no_memory:
+ virReportOOMError();
+
+ goto cleanup;
+
+#undef ADD_ARG
+#undef ADD_ARG_LIT
+#undef ADD_ARG_SPACE
+#undef ADD_USBDISK
+#undef ADD_ENV
+#undef ADD_ENV_COPY
+#undef ADD_ENV_LIT
+#undef ADD_ENV_SPACE
+}
+
diff --git a/src/util/hooks.h b/src/util/hooks.h
new file mode 100644
index 0000000..28fb17e
--- /dev/null
+++ b/src/util/hooks.h
@@ -0,0 +1,77 @@
+/*
+ * hook.h: internal entry points needed for synchronous hooks support
+ *
+ * Copyright (C) 2010 Red Hat, Inc.
+ * Copyright (C) 2010 Daniel Veillard
+ *
+ * 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 Veillard <veillard at redhat.com>
+ */
+
+#ifndef __VIR_HOOKS_H__
+# define __VIR_HOOKS_H__
+
+# include "internal.h"
+# include "util.h"
+
+enum virHookDriverType {
+ VIR_HOOK_DRIVER_DAEMON = 0, /* Daemon related events */
+ VIR_HOOK_DRIVER_QEMU, /* QEmu domains related events */
+ VIR_HOOK_DRIVER_LXC, /* LXC domains related events */
+
+ VIR_HOOK_DRIVER_LAST,
+};
+
+enum virHookDaemonOpType {
+ VIR_HOOK_DAEMON_OP_START, /* daemon is about to start */
+ VIR_HOOK_DAEMON_OP_SHUTDOWN, /* daemon is about to shutdown */
+ VIR_HOOK_DAEMON_OP_RELOAD, /* driver reload with SIGHUP */
+
+ VIR_HOOK_DAEMON_OP_LAST,
+};
+
+enum virHookSubopType {
+ VIR_HOOK_SUBOP_NONE, /* no sub-operation */
+ VIR_HOOK_SUBOP_BEGIN, /* beginning of the operation */
+ VIR_HOOK_SUBOP_END, /* end of the operation */
+
+ VIR_HOOK_SUBOP_LAST,
+};
+
+enum virHookQemuOpType {
+ VIR_HOOK_QEMU_OP_START, /* domain is about to start */
+ VIR_HOOK_QEMU_OP_STOPPED, /* domain has stopped */
+
+ VIR_HOOK_QEMU_OP_LAST,
+};
+
+enum virHookLxcOpType {
+ VIR_HOOK_LXC_OP_START, /* domain is about to start */
+ VIR_HOOK_LXC_OP_STOPPED, /* domain has stopped */
+
+ VIR_HOOK_LXC_OP_LAST,
+};
+
+int virHookInitialize(void);
+
+int virHookPresent(int driver);
+
+int virHookCall(int driver, const char *id, int op, int sub_op,
+ const char *extra, const char *input);
+
+#endif /* __VIR_HOOKS_H__ */
+
+
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel at veillard.com | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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