[libvirt] [RFC] [PATCH 2/5] add fuse support for libvirt lxc

Gao feng gaofeng at cn.fujitsu.com
Wed Jul 11 07:58:20 UTC 2012


this patch addes fuse support for libvirt lxc.
we can use fuse filesystem to generate sysinfo dynamically,
So we can isolate /proc/meminfo,cpuinfo and so on through
fuse filesystem.

we mount fuse filesystem for every container.the mount name
is Lxc-lxcname-fuse.

Signed-off-by: Gao feng <gaofeng at cn.fujitsu.com>
---
 src/Makefile.am          |    9 ++-
 src/lxc/lxc_controller.c |   15 +++++
 src/lxc/lxc_driver.c     |    2 +
 src/lxc/lxc_fuse.c       |  155 ++++++++++++++++++++++++++++++++++++++++++++++
 src/lxc/lxc_fuse.h       |   38 +++++++++++
 5 files changed, 217 insertions(+), 2 deletions(-)
 create mode 100644 src/lxc/lxc_fuse.c
 create mode 100644 src/lxc/lxc_fuse.h

diff --git a/src/Makefile.am b/src/Makefile.am
index 6c3eaa7..b01b2df 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -349,11 +349,13 @@ endif
 
 LXC_DRIVER_SOURCES =						\
 		lxc/lxc_conf.c lxc/lxc_conf.h			\
+		lxc/lxc_fuse.c lxc/lxc_fuse.h			\
 		lxc/lxc_container.c lxc/lxc_container.h		\
 		lxc/lxc_driver.c lxc/lxc_driver.h
 
 LXC_CONTROLLER_SOURCES =					\
 		lxc/lxc_conf.c lxc/lxc_conf.h			\
+		lxc/lxc_fuse.c lxc/lxc_fuse.h			\
 		lxc/lxc_container.c lxc/lxc_container.h		\
 		lxc/lxc_controller.c
 
@@ -819,8 +821,9 @@ endif
 
 libvirt_driver_lxc_impl_la_CFLAGS = \
 		$(LIBNL_CFLAGS) \
+		$(FUSE_CFLAGS) \
 		-I$(top_srcdir)/src/conf $(AM_CFLAGS)
-libvirt_driver_lxc_impl_la_LIBADD = $(CAPNG_LIBS) $(LIBNL_LIBS)
+libvirt_driver_lxc_impl_la_LIBADD = $(CAPNG_LIBS) $(LIBNL_LIBS) $(FUSE_LIBS)
 if HAVE_LIBBLKID
 libvirt_driver_lxc_impl_la_CFLAGS += $(BLKID_CFLAGS)
 libvirt_driver_lxc_impl_la_LIBADD += $(BLKID_LIBS)
@@ -1523,6 +1526,7 @@ libvirt_lxc_SOURCES =						\
 libvirt_lxc_LDFLAGS = $(WARN_CFLAGS) $(AM_LDFLAGS)
 libvirt_lxc_LDADD =			\
 		$(NUMACTL_LIBS) \
+		$(FUSE_LIBS) \
 		libvirt-net-rpc-server.la \
 		libvirt-net-rpc.la \
 		libvirt_driver_security.la \
@@ -1540,7 +1544,8 @@ libvirt_lxc_LDADD += $(APPARMOR_LIBS)
 endif
 libvirt_lxc_CFLAGS =				\
 		-I$(top_srcdir)/src/conf	\
-		$(AM_CFLAGS)
+		$(AM_CFLAGS)			\
+		$(FUSE_CFLAGS)
 if HAVE_LIBBLKID
 libvirt_lxc_CFLAGS += $(BLKID_CFLAGS)
 libvirt_lxc_LDADD += $(BLKID_LIBS)
diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
index a4874ea..44ba07c 100644
--- a/src/lxc/lxc_controller.c
+++ b/src/lxc/lxc_controller.c
@@ -58,6 +58,7 @@
 
 #include "lxc_conf.h"
 #include "lxc_container.h"
+#include "lxc_fuse.h"
 #include "virnetdev.h"
 #include "virnetdevveth.h"
 #include "memory.h"
@@ -1741,6 +1742,20 @@ int main(int argc, char *argv[])
         }
     }
 
+    if ((pid = fork()) < 0)
+        goto cleanup;
+
+    if (pid == 0) {
+        if ((pid = fork()) < 0)
+            _exit(-1);
+
+        if (pid > 0)
+           _exit(0);
+
+        lxcRegisterFuse(ctrl->def);
+        _exit(0);
+    }
+
     rc = virLXCControllerRun(ctrl);
 
 cleanup:
diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
index b58aeae..3f6838f 100644
--- a/src/lxc/lxc_driver.c
+++ b/src/lxc/lxc_driver.c
@@ -41,6 +41,7 @@
 #include "lxc_conf.h"
 #include "lxc_container.h"
 #include "lxc_driver.h"
+#include "lxc_fuse.h"
 #include "memory.h"
 #include "util.h"
 #include "virnetdevbridge.h"
@@ -1485,6 +1486,7 @@ static int lxcVmTerminate(lxc_driver_t *driver,
         return -1;
     }
 
+    lxcUnregisterFuse(vm->def);
     virSecurityManagerRestoreAllLabel(driver->securityManager,
                                       vm->def, false);
     virSecurityManagerReleaseLabel(driver->securityManager, vm->def);
diff --git a/src/lxc/lxc_fuse.c b/src/lxc/lxc_fuse.c
new file mode 100644
index 0000000..5fdacab
--- /dev/null
+++ b/src/lxc/lxc_fuse.c
@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2012 Fujitsu Limited.
+ *
+ * lxc_fuse.c: fuse filesystem support for libvirt lxc
+ *
+ * Authors:
+ *  Gao feng <gaofeng at cn.fujitsu.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
+ */
+
+#include <config.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/mount.h>
+
+#include "virterror_internal.h"
+#include "lxc_fuse.h"
+#include "util.h"
+#include "memory.h"
+
+#define VIR_FROM_THIS VIR_FROM_LXC
+
+#if HAVE_FUSE
+
+static int lxcProcGetattr(const char *path, struct stat *stbuf)
+{
+    int res = 0;
+
+    memset(stbuf, 0, sizeof(struct stat));
+    if (strcmp(path, "/") == 0) {
+        stbuf->st_mode = S_IFDIR | 0755;
+        stbuf->st_nlink = 2;
+    } else
+        res = -ENOENT;
+
+    return res;
+}
+
+static int lxcProcReaddir(const char *path, void *buf,
+                          fuse_fill_dir_t filler,
+                          off_t offset ATTRIBUTE_UNUSED,
+                          struct fuse_file_info *fi ATTRIBUTE_UNUSED)
+{
+    if (strcmp(path, "/") != 0)
+        return -ENOENT;
+
+    filler(buf, ".", NULL, 0);
+    filler(buf, "..", NULL, 0);
+
+    return 0;
+}
+
+static int lxcProcOpen(const char *path ATTRIBUTE_UNUSED,
+                       struct fuse_file_info *fi ATTRIBUTE_UNUSED)
+{
+    return -ENOENT;
+}
+
+static int lxcProcRead(const char *path ATTRIBUTE_UNUSED,
+                       char *buf ATTRIBUTE_UNUSED,
+                       size_t size ATTRIBUTE_UNUSED,
+                       off_t offset ATTRIBUTE_UNUSED,
+                       struct fuse_file_info *fi ATTRIBUTE_UNUSED)
+{
+    return -ENOENT;
+}
+
+static struct fuse_operations lxcProcOper = {
+    .getattr = lxcProcGetattr,
+    .readdir = lxcProcReaddir,
+    .open    = lxcProcOpen,
+    .read    = lxcProcRead,
+};
+
+int lxcRegisterFuse(virDomainDefPtr def)
+{
+    int rc = -1;
+    char *path = NULL;
+    char *name = NULL;
+    int argc = 3;
+    char *argv[argc];
+
+    if ((rc = virAsprintf(&name, "Lxc-%s-fuse", def->name)) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+
+    if ((rc = virAsprintf(&path, "%s/%s/", LXC_STATE_DIR, def->name)) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+
+    if ((rc = virFileMakePath(path)) < 0) {
+        virReportSystemError(errno, _("Cannot create %s"), path);
+        goto cleanup;
+    }
+
+    argv[0] = name;
+    argv[1] = path;
+    argv[2] = (char *)"-odirect_io";
+
+    if ((rc = fuse_main(argc, argv, &lxcProcOper, def)) < 0) {
+        virReportSystemError(errno, "%s", _("Cannot start fuse\n"));
+        goto cleanup;
+    }
+    rc = 0;
+
+cleanup:
+    VIR_FREE(name);
+    VIR_FREE(path);
+    VIR_FREE(argv);
+    return rc;
+}
+
+void lxcUnregisterFuse(virDomainDefPtr def)
+{
+    char *path = NULL;
+    if (virAsprintf(&path, "%s/%s/", LXC_STATE_DIR, def->name) < 0) {
+        virReportOOMError();
+        return;
+    }
+
+    if (umount(path) < 0)
+         virReportSystemError(errno, "%s", _("umount fuse filesystem failed\n"));
+
+    VIR_FREE(path);
+}
+
+#else
+int lxcRegisterFuse(virDomainDefPtr def)
+{
+    (void) def;
+    return 0;
+}
+
+void lxcUnregisterFuse(virDomainDefPtr def)
+{
+    (void) def;
+}
+#endif
diff --git a/src/lxc/lxc_fuse.h b/src/lxc/lxc_fuse.h
new file mode 100644
index 0000000..f87d848
--- /dev/null
+++ b/src/lxc/lxc_fuse.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2012 Fujitsu Limited.
+ *
+ * lxc_fuse.c: fuse filesystem support for libvirt lxc
+ *
+ * Authors:
+ *  Gao feng <gaofeng at cn.fujitsu.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
+ */
+
+#ifndef LXC_FUSE_H
+#define LXC_FUSE_H
+
+#define FUSE_USE_VERSION 26
+
+#include <config.h>
+#if HAVE_FUSE
+#include <fuse.h>
+#endif
+
+#include "lxc_conf.h"
+
+extern int lxcRegisterFuse(virDomainDefPtr def);
+extern void lxcUnregisterFuse(virDomainDefPtr def);
+#endif
-- 
1.7.7.6




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