Re: [libvirt] [PATCHv2] lxc: give RW access to /proc/sys/net/ipv[46] to containers

Some programs want to change some values for the network interfaces configuration in /proc/sys/net/ipv[46] folders. Giving RW access on them allows wicked to work on openSUSE 13.2+. In order to mount those folders RW but keep the rest of /proc/sys RO, we add temporary mounts for these folders before bind-mounting /proc/sys. Those mounts will be skipped if the container doesn't have its own network namespace. It may happen that one of the temporary mounts in /proc/ filesystem isn't available due to a missing kernel feature. We need not to fail in that case. --- Diffs to v1: * Only mount the /proc/sys/net/ipv[46] if the container has its own netns * Don't test for the existence of files in /proc before mounting them: they may not be ready when checking. Instead try to mount them and skip them if the source doesn't exist. * Use existing lxcNeedNetworkNamespace to tell lxcContainerMountBasicFS if we have our own netns: at least we now have the proper value. src/lxc/lxc_container.c | 153 ++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 121 insertions(+), 32 deletions(-) diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index 3b08b86..140d54f 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -800,15 +800,21 @@ typedef struct { int mflags; bool skipUserNS; bool skipUnmounted; + bool skipNoPrivNet; + bool temporary; } virLXCBasicMountInfo; static const virLXCBasicMountInfo lxcBasicMounts[] = { - { "proc", "/proc", "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, false, false }, - { "/proc/sys", "/proc/sys", NULL, MS_BIND|MS_RDONLY, false, false }, - { "sysfs", "/sys", "sysfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, false, false }, - { "securityfs", "/sys/kernel/security", "securityfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, true, true }, + { "proc", "/proc", "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, false, false, false, false }, + { "/proc/sys/net/ipv4", "TMP1", NULL, MS_BIND, false, false, true, true }, + { "/proc/sys/net/ipv6", "TMP2", NULL, MS_BIND, false, false, true, true }, + { "/proc/sys", "/proc/sys", NULL, MS_BIND|MS_RDONLY, false, false, false, false }, + { "TMP1", "/proc/sys/net/ipv4", NULL, MS_BIND, false, false, true, false }, + { "TMP2", "/proc/sys/net/ipv6", NULL, MS_BIND, false, false, true, false }, + { "sysfs", "/sys", "sysfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, false, false, false, false }, + { "securityfs", "/sys/kernel/security", "securityfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, true, true, false, false },