libvirt/src/util/virhook.c
Cédric Bosdonnat 7d3b2eb58f libxl: add hooks support
Introduce libxl hook and use it for start, prepare, started,
stop, stopped, migrate events.
2016-08-02 14:20:31 +02:00

325 lines
8.5 KiB
C

/*
* virhook.c: implementation of the synchronous hooks support
*
* Copyright (C) 2010-2014 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, see
* <http://www.gnu.org/licenses/>.
*
* Author: Daniel Veillard <veillard@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 "virerror.h"
#include "virhook.h"
#include "virutil.h"
#include "virlog.h"
#include "viralloc.h"
#include "virfile.h"
#include "configmake.h"
#include "vircommand.h"
#define VIR_FROM_THIS VIR_FROM_HOOK
VIR_LOG_INIT("util.hook");
#define LIBVIRT_HOOK_DIR SYSCONFDIR "/libvirt/hooks"
VIR_ENUM_DECL(virHookDriver)
VIR_ENUM_DECL(virHookDaemonOp)
VIR_ENUM_DECL(virHookSubop)
VIR_ENUM_DECL(virHookQemuOp)
VIR_ENUM_DECL(virHookLxcOp)
VIR_ENUM_DECL(virHookNetworkOp)
VIR_ENUM_DECL(virHookLibxlOp)
VIR_ENUM_IMPL(virHookDriver,
VIR_HOOK_DRIVER_LAST,
"daemon",
"qemu",
"lxc",
"network",
"libxl")
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",
"prepare",
"release",
"migrate",
"started",
"reconnect",
"attach",
"restore")
VIR_ENUM_IMPL(virHookLxcOp, VIR_HOOK_LXC_OP_LAST,
"start",
"stopped",
"prepare",
"release",
"started",
"reconnect")
VIR_ENUM_IMPL(virHookNetworkOp, VIR_HOOK_NETWORK_OP_LAST,
"start",
"started",
"stopped",
"plugged",
"unplugged",
"updated")
VIR_ENUM_IMPL(virHookLibxlOp, VIR_HOOK_LIBXL_OP_LAST,
"start",
"stopped",
"prepare",
"release",
"migrate",
"started",
"reconnect")
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;
int ret;
if (driver == NULL) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Invalid hook name for #%d"), no);
return -1;
}
if (virBuildPath(&path, LIBVIRT_HOOK_DIR, driver) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to build path for %s hook"),
driver);
return -1;
}
if (!virFileExists(path)) {
ret = 0;
VIR_DEBUG("No hook script %s", path);
} else if (!virFileIsExecutable(path)) {
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 synchronous 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)
{
size_t i;
int 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 unnecessary 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 information
* @input: extra input given to the script on stdin
* @output: optional address of variable to store malloced result buffer
*
* Implement a hook call, where the external script for the driver is
* called with the given information. This is a synchronous call, we wait for
* execution completion. If @output is non-NULL, *output is guaranteed to be
* allocated after successful virHookCall, and is best-effort allocated after
* failed virHookCall; the caller is responsible for freeing *output.
*
* Returns: 0 if the execution succeeded, 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,
char **output)
{
int ret;
char *path;
virCommandPtr cmd;
const char *drvstr;
const char *opstr;
const char *subopstr;
if (output)
*output = 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 SIGHUP
*/
if ((virHooksFound == -1) ||
((driver == VIR_HOOK_DRIVER_DAEMON) &&
(op == VIR_HOOK_DAEMON_OP_RELOAD ||
op == VIR_HOOK_DAEMON_OP_SHUTDOWN)))
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;
case VIR_HOOK_DRIVER_LIBXL:
opstr = virHookLibxlOpTypeToString(op);
break;
case VIR_HOOK_DRIVER_NETWORK:
opstr = virHookNetworkOpTypeToString(op);
}
if (opstr == NULL) {
virReportError(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 = "-";
if (virBuildPath(&path, LIBVIRT_HOOK_DIR, drvstr) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to build path for %s hook"),
drvstr);
return -1;
}
VIR_DEBUG("Calling hook opstr=%s subopstr=%s extra=%s",
opstr, subopstr, extra);
cmd = virCommandNewArgList(path, id, opstr, subopstr, extra, NULL);
virCommandAddEnvPassCommon(cmd);
if (input)
virCommandSetInputBuffer(cmd, input);
if (output)
virCommandSetOutputBuffer(cmd, output);
ret = virCommandRun(cmd, NULL);
if (ret < 0) {
/* Convert INTERNAL_ERROR into known error. */
virReportError(VIR_ERR_HOOK_SCRIPT_FAILED, "%s",
virGetLastErrorMessage());
}
virCommandFree(cmd);
VIR_FREE(path);
return ret;
}