libvirt/src/lxc/lxc_conf.c
Daniel P. Berrange 4f2094a8a6 Allow 32-on-64 execution for LXC guests
Using the 'personality(2)' system call, we can make a container
on an x86_64 host appear to be i686. Likewise for most other
Linux 64bit arches.

* src/lxc/lxc_conf.c: Fill in 32bit capabilities for x86_64 hosts
* src/lxc/lxc_container.h, src/lxc/lxc_container.c: Add API to
  check if an arch has a 32bit alternative
* src/lxc/lxc_controller.c: Set the process personality when
  starting guest
2011-02-24 12:04:29 +00:00

169 lines
5.1 KiB
C

/*
* Copyright (C) 2010 Red Hat, Inc.
* Copyright IBM Corp. 2008
*
* lxc_conf.c: config functions for managing linux containers
*
* Authors:
* David L. Leskovec <dlesko at linux.vnet.ibm.com>
*
* 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
*
*/
/* includes */
#include <config.h>
#include <sys/utsname.h>
#include "lxc_conf.h"
#include "nodeinfo.h"
#include "virterror_internal.h"
#include "conf.h"
#include "memory.h"
#include "logging.h"
#include "uuid.h"
#include "configmake.h"
#include "lxc_container.h"
#define VIR_FROM_THIS VIR_FROM_LXC
/* Functions */
virCapsPtr lxcCapsInit(void)
{
struct utsname utsname;
virCapsPtr caps;
virCapsGuestPtr guest;
const char *altArch;
uname(&utsname);
if ((caps = virCapabilitiesNew(utsname.machine,
0, 0)) == NULL)
goto error;
/* Some machines have problematic NUMA toplogy causing
* unexpected failures. We don't want to break the QEMU
* driver in this scenario, so log errors & carry on
*/
if (nodeCapsInitNUMA(caps) < 0) {
virCapabilitiesFreeNUMAInfo(caps);
VIR_WARN0("Failed to query host NUMA topology, disabling NUMA capabilities");
}
if (virGetHostUUID(caps->host.host_uuid)) {
lxcError(VIR_ERR_INTERNAL_ERROR,
"%s", _("cannot get the host uuid"));
goto error;
}
/* XXX shouldn't 'borrow' KVM's prefix */
virCapabilitiesSetMacPrefix(caps, (unsigned char []){ 0x52, 0x54, 0x00 });
if ((guest = virCapabilitiesAddGuest(caps,
"exe",
utsname.machine,
sizeof(void*) == 4 ? 32 : 64,
LIBEXECDIR "/libvirt_lxc",
NULL,
0,
NULL)) == NULL)
goto error;
if (virCapabilitiesAddGuestDomain(guest,
"lxc",
NULL,
NULL,
0,
NULL) == NULL)
goto error;
/* On 64-bit hosts, we can use personality() to request a 32bit process */
if ((altArch = lxcContainerGetAlt32bitArch(utsname.machine)) != NULL) {
if ((guest = virCapabilitiesAddGuest(caps,
"exe",
altArch,
32,
LIBEXECDIR "/libvirt_lxc",
NULL,
0,
NULL)) == NULL)
goto error;
if (virCapabilitiesAddGuestDomain(guest,
"lxc",
NULL,
NULL,
0,
NULL) == NULL)
goto error;
}
/* LXC Requires an emulator in the XML */
virCapabilitiesSetEmulatorRequired(caps);
return caps;
error:
virCapabilitiesFree(caps);
return NULL;
}
int lxcLoadDriverConfig(lxc_driver_t *driver)
{
char *filename;
virConfPtr conf;
virConfValuePtr p;
/* Set the container configuration directory */
if ((driver->configDir = strdup(LXC_CONFIG_DIR)) == NULL)
goto no_memory;
if ((driver->stateDir = strdup(LXC_STATE_DIR)) == NULL)
goto no_memory;
if ((driver->logDir = strdup(LXC_LOG_DIR)) == NULL)
goto no_memory;
if ((driver->autostartDir = strdup(LXC_AUTOSTART_DIR)) == NULL)
goto no_memory;
if ((filename = strdup(SYSCONFDIR "/libvirt/lxc.conf")) == NULL)
goto no_memory;
/* Avoid error from non-existant or unreadable file. */
if (access (filename, R_OK) == -1)
goto done;
conf = virConfReadFile(filename, 0);
if (!conf)
goto done;
p = virConfGetValue(conf, "log_with_libvirtd");
if (p) {
if (p->type != VIR_CONF_LONG)
VIR_WARN0("lxcLoadDriverConfig: invalid setting: log_with_libvirtd");
else
driver->log_libvirtd = p->l;
}
virConfFree(conf);
done:
VIR_FREE(filename);
return 0;
no_memory:
virReportOOMError();
return -1;
}