1:40 a.m.
ping
-----Original Message-----
From: libvir-list-bounces(a)redhat.com [mailto:libvir-list-bounces@redhat.com]
On Behalf Of Chen Hanxiao
Sent: Monday, July 14, 2014 6:02 PM
To: libvir-list(a)redhat.com
Subject: [libvirt] [PATCH] LXC: create a bind mount for sysfs when enable userns
but disable netns
kernel commit 7dc5dbc879bd0779924b5132a48b731a0bc04a1e
forbid us doing a fresh mount for sysfs
when enable userns but disable netns.
This patch will create a bind mount in this senario.
Signed-off-by: Chen Hanxiao <chenhanxiao(a)cn.fujitsu.com>
---
src/lxc/lxc_container.c | 44 +++++++++++++++++++++++++++++++++-----------
1 file changed, 33 insertions(+), 11 deletions(-)
diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c
index 4d89677..8a27215 100644
--- a/src/lxc/lxc_container.c
+++ b/src/lxc/lxc_container.c
@@ -815,10 +815,13 @@ static int lxcContainerSetReadOnly(void)
}
-static int lxcContainerMountBasicFS(bool userns_enabled)
+static int lxcContainerMountBasicFS(bool userns_enabled,
+ bool netns_disabled)
{
size_t i;
int rc = -1;
+ char* mnt_src = NULL;
+ int mnt_mflags;
VIR_DEBUG("Mounting basic filesystems");
@@ -826,8 +829,25 @@ static int lxcContainerMountBasicFS(bool userns_enabled)
bool bindOverReadonly;
virLXCBasicMountInfo const *mnt = &lxcBasicMounts[i];
+ /* When enable userns but disable netns, kernel will
+ * forbid us doing a new fresh mount for sysfs.
+ * So we had to do a bind mount for sysfs instead.
+ */
+ if (userns_enabled && netns_disabled &&
+ STREQ(mnt->src, "sysfs")) {
+ if (VIR_STRDUP(mnt_src, "/sys") < 0) {
+ goto cleanup;
+ }
+ mnt_mflags = MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY|MS_BIND;
+ } else {
+ if (VIR_STRDUP(mnt_src, mnt->src) < 0) {
+ goto cleanup;
+ }
+ mnt_mflags = mnt->mflags;
+ }
+
VIR_DEBUG("Processing %s -> %s",
- mnt->src, mnt->dst);
+ mnt_src, mnt->dst);
if (mnt->skipUnmounted) {
char *hostdir;
@@ -856,7 +876,7 @@ static int lxcContainerMountBasicFS(bool userns_enabled)
if (virFileMakePath(mnt->dst) < 0) {
virReportSystemError(errno,
_("Failed to mkdir %s"),
- mnt->src);
+ mnt_src);
goto cleanup;
}
@@ -867,24 +887,24 @@ static int lxcContainerMountBasicFS(bool userns_enabled)
* we mount the filesystem in read-write mode initially, and then do a
* separate read-only bind mount on top of that.
*/
- bindOverReadonly = !!(mnt->mflags & MS_RDONLY);
+ bindOverReadonly = !!(mnt_mflags & MS_RDONLY);
VIR_DEBUG("Mount %s on %s type=%s flags=%x",
- mnt->src, mnt->dst, mnt->type, mnt->mflags &
~MS_RDONLY);
- if (mount(mnt->src, mnt->dst, mnt->type, mnt->mflags &
~MS_RDONLY, NULL)
< 0) {
+ mnt_src, mnt->dst, mnt->type, mnt_mflags & ~MS_RDONLY);
+ if (mount(mnt_src, mnt->dst, mnt->type, mnt_mflags & ~MS_RDONLY,
NULL)
< 0) {
virReportSystemError(errno,
_("Failed to mount %s on %s type %s
flags=%x"),
- mnt->src, mnt->dst, NULLSTR(mnt->type),
- mnt->mflags & ~MS_RDONLY);
+ mnt_src, mnt->dst, NULLSTR(mnt->type),
+ mnt_mflags & ~MS_RDONLY);
goto cleanup;
}
if (bindOverReadonly &&
- mount(mnt->src, mnt->dst, NULL,
+ mount(mnt_src, mnt->dst, NULL,
MS_BIND|MS_REMOUNT|MS_RDONLY, NULL) < 0) {
virReportSystemError(errno,
_("Failed to re-mount %s on %s flags=%x"),
- mnt->src, mnt->dst,
+ mnt_src, mnt->dst,
MS_BIND|MS_REMOUNT|MS_RDONLY);
goto cleanup;
}
@@ -893,6 +913,7 @@ static int lxcContainerMountBasicFS(bool userns_enabled)
rc = 0;
cleanup:
+ VIR_FREE(mnt_src);
VIR_DEBUG("rc=%d", rc);
return rc;
}
@@ -1643,7 +1664,8 @@ static int lxcContainerSetupPivotRoot(virDomainDefPtr
vmDef,
goto cleanup;
/* Mounts the core /proc, /sys, etc filesystems */
- if (lxcContainerMountBasicFS(vmDef->idmap.nuidmap) < 0)
+ if (lxcContainerMountBasicFS(vmDef->idmap.nuidmap,
+ !vmDef->nnets) < 0)
goto cleanup;
/* Ensure entire root filesystem (except /.oldroot) is readonly */
--
1.9.0
--
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