libvirt-lxc: add virDomainLxcEnterCGroup API

Add the virDomainLxcEnterCGroup API to the libvirt-lxc.so
file. This method moves the calling process into the cgroups
associated with the container.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

config-post.h

@@ -32,6 +32,7 @@
 # undef HAVE_LIBSASL2
 # undef WITH_CAPNG
 # undef WITH_CURL
+# undef WITH_DBUS
 # undef WITH_DTRACE_PROBES
 # undef WITH_GNUTLS
 # undef WITH_GNUTLS_GCRYPT
@@ -39,6 +40,7 @@
 # undef WITH_NUMACTL
 # undef WITH_SASL
 # undef WITH_SSH2
+# undef WITH_SYSTEMD_DAEMON
 # undef WITH_VIRTUALPORT
 # undef WITH_YAJL
 # undef WITH_YAJL2

include/libvirt/libvirt-lxc.h

@@ -46,6 +46,8 @@ int virDomainLxcEnterSecurityLabel(virSecurityModelPtr model,
                                    virSecurityLabelPtr label,
                                    virSecurityLabelPtr oldlabel,
                                    unsigned int flags);
+int virDomainLxcEnterCGroup(virDomainPtr domain,
+                            unsigned int flags);
 
 # ifdef __cplusplus
 }

src/Makefile.am

@@ -2327,8 +2327,10 @@ libvirt_setuid_rpc_client_la_SOURCES = 		\
 		util/viratomic.h		\
 		util/virbitmap.c		\
 		util/virbuffer.c		\
+		util/vircgroup.c		\
 		util/vircommand.c		\
 		util/virconf.c			\
+		util/virdbus.c			\
 		util/virerror.c			\
 		util/virevent.c			\
 		util/vireventpoll.c		\
@@ -2336,6 +2338,7 @@ libvirt_setuid_rpc_client_la_SOURCES = 		\
 		util/virgettext.c		\
 		util/virhash.c			\
 		util/virhashcode.c		\
+		util/virhostcpu.c		\
 		util/virjson.c			\
 		util/virlog.c			\
 		util/virobject.c		\
@@ -2344,6 +2347,7 @@ libvirt_setuid_rpc_client_la_SOURCES = 		\
 		util/virrandom.c		\
 		util/virsocketaddr.c		\
 		util/virstring.c		\
+		util/virsystemd.c		\
 		util/virtime.c			\
 		util/virthread.c		\
 		util/virthreadjob.c		\

src/libvirt-lxc.c

@@ -36,6 +36,7 @@
 #ifdef WITH_APPARMOR
 # include <sys/apparmor.h>
 #endif
+#include "vircgroup.h"
 
 #define VIR_FROM_THIS VIR_FROM_NONE
 
@@ -269,3 +270,49 @@ virDomainLxcEnterSecurityLabel(virSecurityModelPtr model,
     virDispatchError(NULL);
     return -1;
 }
+
+
+/**
+ * virDomainLxcEnterCGroup:
+ * @domain: a domain object
+ * @flags: currently unused, pass 0
+ *
+ * This API is LXC specific, so it will only work with hypervisor
+ * connections to the LXC driver.
+ *
+ * Attaches the process to the control cgroups associated
+ * with the container @domain.
+ *
+ * Returns 0 on success, -1 on error
+ */
+int virDomainLxcEnterCGroup(virDomainPtr domain,
+                            unsigned int flags)
+{
+    virConnectPtr conn;
+    virCgroupPtr cgroup = NULL;
+
+    VIR_DOMAIN_DEBUG(domain, "flags=%x", flags);
+
+    virResetLastError();
+
+    virCheckDomainReturn(domain, -1);
+    conn = domain->conn;
+
+    virCheckReadOnlyGoto(conn->flags, error);
+    virCheckFlagsGoto(0, error);
+
+    if (virCgroupNewDetect(domain->id, -1, &cgroup) < 0)
+        goto error;
+
+    if (virCgroupAddTask(cgroup, getpid()) < 0)
+        goto error;
+
+    virCgroupFree(&cgroup);
+
+    return 0;
+
+ error:
+    virDispatchError(NULL);
+    virCgroupFree(&cgroup);
+    return -1;
+}

src/libvirt_lxc.syms

@@ -20,3 +20,8 @@ LIBVIRT_LXC_1.0.4 {
     global:
         virDomainLxcEnterSecurityLabel;
 } LIBVIRT_LXC_1.0.2;
+
+LIBVIRT_LXC_1.3.6 {
+    global:
+        virDomainLxcEnterCGroup;
+} LIBVIRT_LXC_1.0.4;