Some of echo $(...) code segment is pointless, just call the command
directly, and remove some useless if / return statement.
Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Pingfan Liu <piliu@redhat.com>
When trying to setup kdump for fedora-coreos, kdumpctl start fails to
find the correct boot directory since BOOT_IMAGE start with the grub
device name
Signed-off-by: Yuval Turgeman <yturgema@redhat.com>
When reading kdump configs, a single parsing should be enough and this
saves a lot of duplicated striping call which speed up the total load
speed.
Speed up about 2 second when building and 0.1 second for reload in my
tests.
Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
In preparation for adding 'final_action' option, since it's confusing
to have the 'final_action' and 'default' options at the same time,
this patch introduces 'failure_action' as an alias of the 'default'
option to /etc/kdump.conf, and makes 'default' obsolete to be removed
in the future.
Also, the "default action" term is renamed to "failure action".
Signed-off-by: Kazuhito Hagio <k-hagio@ab.jp.nec.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Lianbo Jiang <lijiang@redhat.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Kairui Song <kasong@redhat.com>
we move some common functions from kdumpctl to kdump-lib.sh, the
functions could be used in other modules, such as early kdump.
It has no bad effect.
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Reviewed-by: Kazuhito Hagio <khagio@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
This reverts commit 2f4149f276.
It is not proved to be right to get auto6 or dhcpv6 in 1st kernel,
pingfan is working on a dracut fix to do some fallback in 2nd kernel initramfs.
So revert this commit
Kdump always use _proto=dhcp for both ipv4 and ipv6. But for ipv6
the dhcp address assignment is not like ipv4, there are different ways
for it, stateless and stateful, see below document:
https://fedoraproject.org/wiki/IPv6Guide
In case stateless, kernel can do the address assignment, dracut use
_proto=auto6; for stateful case, dracut use _proto=dhcp6.
We do not see bug reports before because for the most auto6 cases
kernel assign ip address before dhclient, kdump just happened to work.
Here we use auto6 if possible first. And we take the assumption that
host use auto6 if /proc/sys/net/ipv6/conf/$netdev/autoconf is enabled
Signed-off-by: Pingfan Liu <piliu@redhat.com>
Dracut has "--hostonly-cmdline" which can generate cmdlines(if any)
regarding the dump target, it's an existing way for us to use to
simplify the code. E.g. We already removed generate_lvm_cmdlines(),
to use "--hostonly-cmdline".
But "--hostonly-cmdline" has other issues(e.g. BZ1451717), it adds
needless devices for kdump like root device.
Now dracut supports "--no-hostonly-default-device" which enables
us to only add the kdump target, which can avoid needless devices
being recognized under kdump. Thus "--hostonly-cmdline" side effects
can be avoided with the help of "--no-hostonly-default-device".
This patch applies dracut's "--hostonly-cmdline" together with
"--no-hostonly-default-device" to achieve above-mentioned purpose.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Make is_fadump_capable() a library function, as we will need
it in mkdumprd.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
This reverts commit 54a5bcc4ee.
We are going to add "--no-hostonly-default-device" dracut argument
in the following patch.
With the help of "--no-hostonly-default-device", dracut only
adds the dump target as host devices, which naturally guarantees
only required dracut modules being selected.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Resolves: bz1451717
https://bugzilla.redhat.com/1451717
When there is no crypt related kdump target, we can safely
omit "crypt" dracut module, this can avoid the pop asking
disk password during kdump boot in some cases.
This patch introduces omit_dracut_modules() before calling
dracut, we can omit more modules to reduce initrd size in
the future.
We don't want to omit any module for fadump, thus we move
is_fadump_capable() into kdump-lib.sh as a helper to use.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Resolves: bz1451717
https://bugzilla.redhat.com/1451717
We need to know all the kdump targets including the dump
target and root in case of "dump_to_rootfs".
This is useful for us to do some extra work related to the
type of different targets.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Resolves: bz1451717
https://bugzilla.redhat.com/1451717
This patch improves get_block_dump_target as follows:
-Consider block device in the special "--dracut-args --mount ..."
in get_user_configured_dump_disk().
-Consider save path instead of root fs in get_block_dump_target(),
and move it into kdump-lib.sh because we will have another user
in the following patch.
-For nfs/ssh dumping, there is no need to check the root device.
-Move get_save_path into kdump-lib.sh.
After this patch, get_block_dump_target() can always return the
correct block dump target specified.
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
For -q option, as man grep says: Exit immediately with zero status if
any match is found, even if an error was detected.
So when matching, the read side of pipe is closed by "grep -q", while
the write side still try to write more data, which cause SIGPIPE to the
process, and the shell can not exit with 0. It depends on the kernel's
implementation of pipe to decide how much data written by the producer
can trigger the bug.
Bash test script:
#!/bin/sh
set -o pipefail
dd if=/dev/zero of=text.file bs=1M count=1
sed -i '1s/^/keyword /' text.file
cat text.file | grep -q keyword
echo $?
Notice the "set -o pipefail" is set by dracut, so
mkdumprd -> dracut -> dracut-module-setup.sh -> is_pcs_fence_kdump()
trigger the bug.
Signed-off-by: Pingfan Liu <piliu@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Pratyush Anand <panand@redhat.com>
We maintained several kdump specific functions which are duplicate with the
similar versions in dracut, Dracut upstream splitted dracut init stuff from
dracut-functions.sh so that we can source it now.
Notes about kdump_get_presistent_dev:
Dracut now has a persistent_policy feature, for kdump when we dump to
raw disks we do not care the filesystem uuid and labels so we prefer to
search disk id instead. For raw disk set the persistent_policy before calling
get_persistent_dev ensure kdump logic still work.
Tested filesystem and raw dump in kvm guests.
[Xunlei: drop other functions other than get_persistent_dev.]
Signed-off-by: Dave Young <dyoung@redhat.com>
Reviewed-by: Xunlei Pang <xlpang@redhat.com>
We get following error on the systems that have everything built-in and no
initrd is used.
Kernel dev name of /dev/root is not found.
Dump target /dev/root is probably not mounted.
It happens because `df $path` gets /dev/root from /proc/self/mountinfo.
Fix this by identifying real target device when `df $path` returns
Filesystem as /dev/root.
Reported-and-tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Pratyush Anand <panand@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
There are some complaints about nfs kdump that users must mount
nfs beforehand, which may cause some overhead to nfs server.
For example, there're thounsands of diskless clients deployed with
nfs dumping, each time the client is boot up, it will trigger
kdump rebuilding so will mount nfs, thus resulting in thousands
of nfs request concurrently imposed on the same nfs server.
We introduce a new way of specifying mount information via the
already-existent "dracut_args" directive(so avoid adding extra
directives in /etc/kdump.conf), we will skip all the filesystem
mounting and checking stuff for it. So it can be used in the
above-mentioned nfs scenario to avoid severe nfs server overhead.
Specifically, if there is any "--mount" information specified via
"dracut_args" in /etc/kdump.conf, always use it as the final mount
without any validation(mounting or checking like mount options,
fs size, etc), so users are expected to ensure its correctness.
NOTE:
-Only one mount target is allowed using "dracut_args" globally.
-Dracut will create <mountpoint> if it doesn't exist in kdump kernel,
<mountpoint> must be specified as an absolute path.
-Users should do a test first and ensure it works because kdump does
not prepare the mount or check all the validity.
Reviewed-by: Pratyush Anand <panand@redhat.com>
Suggested-by: Dave Young <dyoung@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
If dracut watchdog module is enabled then, it includes kernel watchdog
module of active watchdog device in initramfs.
kdump.conf has an option to modify dracut_args. So, if an user passes "-a
watchdog" in dracut_args then dracut will add kernel watchdog module of
active watchdog device in initramfs.
Since, kexec-tools always requires to add kernel watchdog module of active
watchdog device in initramfs, therefore even when an user does not pass any
watchdog option and there exists at least one active watchdog device then
also kexec-tools adds "-a watchdog" in dracut args.
Therefore, if an user does not want to add kernel watchdog module in
initramfs then the person must pass "-o watchdog" in dracut_args.
Signed-off-by: Pratyush Anand <panand@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Resolves: BZ1348898
dracut-functions.sh defines a get_persistent_dev(). Earlier, we had another
local get_persistent_dev() in mkdumprd, however that was moved to
kdump-lib.sh, so that it can be reused in kdumpctl.
Since, dracut-module-setup.sh (which is dracut's
99kdumpbase/module-setup.sh) sources kdump-lib.sh. Therefore, once dracut
will execute 99kdumpbase module, it's own get_persistent_dev() function is
overwritten by kdump's version. If any other dracut module calls
get_persistent_dev() thereafter then, kdump's version is executed, which was
not expected.
Therefore rename kdump's get_persistent_dev() as kdump_get_persistent_dev()
to avoid any name contention.
Signed-off-by: Pratyush Anand <panand@redhat.com>
Acked-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Previously, we assumed the ifcfg file of a network "interface" is
"/etc/sysconfig/network-scripts/ifcfg-<interface>", but actually
it is not the case.
For example, for network interface "enp0s25", we are able to
generate like "/etc/sysconfig/network-scripts/ifcfg-enp0s25-test"
for it via network-manager.
The "suffix" in "ifcfg-<suffix>" is actually a "configuration"
name not "interface" name, though normally we use the "interface"
name as its "configuration" name. You can refer to "man ifup"
for some detail.
So, this patch adds some assistant helpers to acquire the right
ifcfg file for an interface. Borrow some logic from script below:
"/etc/sysconfig/network-scripts/network-functions"
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
to_dev_name() and get_persistent_dev() can be used by function in kdumpctl.
Therefore moving them to kdump-lib.sh.
No functional changes.
Signed-off-by: Pratyush Anand <panand@redhat.com>
Acked-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Baoquan He <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Previously, Kdump will save route to setup the network route in the 2nd
kernel for ipv4 protocol. To support ipv6 protocol, make Kdump fetch
correct nexthop, since the ruturning format is different.
In order to enhance kdump to support ipv6, support the static ip for
ipv6 protocol, which ipv4 has supported already.
Introduce a new lib function get_remote_host which is used to factor out
the ip address(ipv4 or ipv6) and hostname in /etc/kdump.conf.
Introduce a new lib function is_ipv6_address which is used to make sure
whether the passed ip address is ipv4 or ipv6.
Introduce a new lib function is_hostname which is used to confirm
whether the passed parameter is hostname, not the ip address.
Introduce a new function get_ip_route_field which is used to factor out
the specified string in ip route info.
Due to the different format between ipv4 and ipv6 protocol, quote the
ipv6 address with bracket "[]" to make dracut notify.
Signed-off-by: Minfei Huang <mhuang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
The ipv6 patchset is still under review, previously the commit was mistakenly
merged, thus let's revert it.
Revert "dracut-kdump: Use proper the known hosts entry in the file known_hosts"
This reverts commit 63476302aa.
Conflicts:
kdump-lib.sh
Signed-off-by: Minfei Huang <mhuang@redhat.com>
Signed-off-by: Dave Young <dyoung@redhat.com>
kdump will raise the warning in Atomic, if the path is bind mounted
directory. The reason why causes this issue is kdump cannt parse the
bind mounted directory.
To correct dumping target, we can construct the real dumping path in
Atomic, which contains two part, one bind mounted path, the other
specified dump target.
Following is an example:
-bash-4.2# cat /etc/kdump.conf | grep ^path
path /var/crash
-bash-4.2# findmnt /var | tail -n 1 | awk '{print $2}'
/dev/mapper/atomicos-root[/ostree/deploy/rhel-atomic-host/var]
-bash-4.2# findmnt -v /var | tail -n 1 | awk '{print $2}'
/dev/mapper/atomicos-root
Then we can found it that the real path of dumping vmcore is
/ostree/deploy/rhel-atomic-host/var/crash.
To fix this issue, we can replace the target path as the real path which
is from above parsing.
Signed-off-by: Minfei Huang <mhuang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Any block device can be mounted multiply on the different mount point.
Once a mount point is mounted in bind mode, the general mount point can
be unmounted. Thus kdump would not find the general mount point[1] to
handle the path.
The mount point, which is as general mount point, will be got by
"fintmnt" previously. But the mntpoint may be incorrect, if the mntpoint
is bind mount.
In order to fix it to support bind mounted in atomic, we will add a
judgement to comfirm the mntpoint is bind mounted, or not.
For general mount, returning path is like following, if we use
"findmnt". The returning is same as "findmnt -v".
-bash-4.2# findmnt /var | tail -n 1 | awk '{print $2}'
/dev/mapper/atomicos-root
But for bind mount, returning path is like following, if we use
"fintmnt".
-bash-4.2# findmnt /var | tail -n 1 | awk '{print $2}'
/dev/mapper/atomicos-root[/ostree/deploy/rhel-atomic-host/var]
Use "findmnt -v" is like this:
-bash-4.2# findmnt -v /var | tail -n 1 | awk '{print $2}'
/dev/mapper/atomicos-root
So we can determine the bind mount, if the returning is different
between "findmnt" and "findmnt -v".
[1] general mount point is a directory without being in bind mounted
mode, just a normal directory.
Signed-off-by: Minfei Huang <mhuang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
For Atomic system, the cmdline will contain the specific string
"ostree". So we can filter out the "ostree" to judge the system is
Atomic or not.
Signed-off-by: Minfei Huang <mhuang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
findmnt uses the option "-v, --nofsroot" to exclude the [/dir] in the
SOURCE column for bind-mounts, then if $_mntpoint equals to
$_mntpoint_nofsroot, the mountpoint is not bind mounted directory.
the value of $_mntpoint may be like
/dev/mapper/atomicos-root[/ostree/deploy/rhel-atomic-host/var], if the
directory is bind mounted. The former part represents the device path, the
rest part is the bind mounted directory which quotes by bracket "[]".
Signed-off-by: Minfei Huang <mhuang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Once login using ssh, the ssh will store the known hosts entry to the
local ~/.ssh/known_hosts. From now, we can login using ssh automaticly.
The ssh will check the ~/ssh/.known_hosts entry, if set the option
StrictHostKeyChecking=yes/ask in the config or command line, when you
want to login the target. the default value of StrictHostKeyChecking is
ask.
And the kdump using the ssh will append the option
StrictHostKeyChecking=yes in the command line.
We can using following ip to connect peer machine, if enable the ipv6.
fe80::5054:ff:fe48:ca80%eth0
Obviously, above ip contains the ethX.
Kdump will add the prefix "kdump-" before ethX to avoid flowing
netdevice name in case netdevice names ethX in the 2nd kernel. So the
ip address will change to fe80::5054:ff:fe48:ca80%kdump-eth0.
Kdump will login the target manully in the 2nd kernel, because of the
option StrictHostKeyChecking=yes and inexistence known hosts entry
in the local ~/.ssh/known_hosts. Hence dumping core will fail.
In order to login automaticly using ssh, we should add the prefix
"kdump-" before ethX in the local ~/.ssh/known_hosts.
Signed-off-by: Minfei Huang <mhuang@redhat.com>
get_option_value() is used to get the value of $1 configured in
/etc/kdump.conf. But when we use "get_option_value ssh", it can get the
value of "sshkey" instead of "ssh".
Fix the regexp pattern to get an exact match.
Signed-off-by: WANG Chao <chaowang@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
When user does not specify dump target explicitly, it's better to
dump to the "path" specified. That means after dump user enter into
1st kernel, can find vmcore in the "path". If that path is in root
fs, vmcore is stored in root fs. If separate disk is mounted on
any tier of "path", we just dump vmcore into the left path on the
left separate disk.
E.g in kdump.conf
path /mnt/nfs
in mount info,
/dev/vdb on /mnt type ext4 (rw,relatime,seclabel,data=ordered)
Then vmcore will be saved in /nfs of /dev/vdb.
In this patch, pass mount info to dracut in this case if separate
disk is mounted on any tier of "path".
Meanwhile introduce a function in kdump-lib.sh to check if any
target is specified.
v4->v5:
Per Vivek's comment, add a helper function is_fs_dump_target.
Then is_user_configured_dump_target is rewrite with these helper
functions.
v5->v7:
No v6 for this patch. Just use newly introduced function
is_fs_type_nfs in handle_default_dump_target.
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
kdump need create the dir specified in "path" formerly if it does not
exist. Now change the behavior to be that ueser takes charge of the
"path", make sure "path" has been created, especially when separate disk
is mounted on this "path".
Also introduce 2 helper functions to help check the existence of path.
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
These utility function will be shared by several files, they are all
operation related to mount stuff.
Meantime define DEFAULT_PATH="/var/crash".
v5-> v6:
Since in rhel7 nfs4 becomes default nfs version, and its fstype is
nfs4. So change the implementation of get_fs_type_from_target(),
whatever fstype returned from findmount, just echo nfs as fstype for all
nfs version.
v6->v7:
Introduce is_fs_type_nfs to check if fstype is nfs or nfs4 per Vivek's
idea.
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Adds two new options to kdump.conf to be able to configure fence_kdump
support for generic clusters:
fence_kdump_args <arg(s)>
- Command line arguments for fence_kdump_send (it can contain all
valid arguments except hosts to send notification to)
fence_kdump_nodes <node(s)>
- List of cluster node(s) separated by space to send fence_kdump
notification to (this option is mandatory to enable fence_kdump)
Generic clusters fence_kdump configuration take precedence over older
method of fence_kdump configuration for Pacemaker clusters. It means
that if fence_kdump is configured using above options in kdump.conf, old
Pacemaker configuration is not used even if it exists.
Bug-Url: https://bugzilla.redhat.com/1078134
Signed-off-by: Martin Perina <mperina@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Adds get_option_value() function to retrieve value of specified option
from /etc/kdump.conf.
Bug-Url: https://bugzilla.redhat.com/1078134
Signed-off-by: Martin Perina <mperina@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Renames is_fence_kdump to is_pcs_fence_kdump to identify that this
method should be used to detect fence_kdump configuration only in
Pacemaker clusters.
Bug-Url: https://bugzilla.redhat.com/1078134
Signed-off-by: Martin Perina <mperina@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Renames FENCE_KDUMP_NODES variable to FENCE_KDUMP_NODES_FILE to
distinguish it from values read from fence_kdump_nodes option in
kdump.conf (introduced in following patches).
Bug-Url: https://bugzilla.redhat.com/1078134
Signed-off-by: Martin Perina <mperina@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Renames FENCE_KDUMP_CONFIG variable to FENCE_KDUMP_CONFIG_FILE to
distinguish it from values read from fence_kdump_args option in
kdump.conf (introduced in following patches).
Bug-Url: https://bugzilla.redhat.com/1078134
Signed-off-by: Martin Perina <mperina@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Now when dump target is not specified, separate disk can't be mounted on
"path", e.g /var/crash. However if target is specified, whatever the default
fail action is set, mkdumprd should go ahead and not be failed.
In check_block_dump_target(), the check only on disk is not complete,
NFS and ssh need be filtered too. So introduce is_user_configured_dump_target
to check this.
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
In function get_block_dump_target(), code block to get user configured
dump disk and get root fs device can be reused by other places. Now
abstract and wrap them into 2 new functions:
get_user_configured_dump_disk()
get_root_fs_device()
And put them into kdump-lib.sh.
Meanwhile change the get_block_dump_target() accordingly.
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Add following common variables and function:
$FENCE_KDUMP_CONIFG: configuration file /etc/sysconfig/fence_kdump
$FENCE_KDUMP_NODES: configuration file /etc/fence_kdump_nodes
$FENCE_KDUMP_SEND: executable /usr/libexec/fence_kdump_send
is_fence_kdump(): used to determine if the system is in a cluster and
configured with fence_kdump.
Signed-off-by: WANG Chao <chaowang@redhat.com>
Tested-by: Zhi Zou <zzou@redhat.com>
Tested-by: Marek Grac <mgrac@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
In mkdumprd, strip_comments is not implemented correctly. Since arguments
passed, strip_comments only take $1 and misses others. This caused
problems. Such as below line, current code will only get "makedumpfile"
and pass it to $config_val finally, then parameters for makedumpfile
are missed.
core_collector makedumpfile -c --message-level 1 -d 31
Now modify function strip_comments.
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: WANG Chao <chaowang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Add function strip_comments into kdump-lib.sh, since it's used by
several files.
Signed-off-by: Wade Mealing <wmealing@redhat.com>
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Currently in the whole kdump framework, we have some common functions
used across not only mkdumprd context and dracut context, but also 1st
kernel and 2nd kernel. We defined these functions at each script, which
is obviously not decent.
So let's introduce kdump-lib.sh for the shared functions and put it
to /lib/kdump/kdump-lib.sh.
It starts small, as you can see, only 3 functions are extracted. But in
the future more and more common functions can be added.
Signed-off-by: WANG Chao <chaowang@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
