[PATCH 3/8 v10] kdump-lib: Add functions to enhance ipv6 judgement

[Minfei Huang]

The ipv6 address has the special character colon ":", so we can use the
new function to pick it out.
We can use the new function to parse the passed parameter. The passed
parameter is hostname/domain, if it is satisfied with the condition that
it is without colon ":", and contanis the [a-zA-Z].

Add a new function to simplify to get the ip address, if the specified
address is a domain/hostname in /etc/kdump.conf.
The function will parse the passed parameter, and use the "getent ahost"
to get the ip address, if passed parameter is domain/hostname.

Signed-off-by: Minfei Huang <mhuang(a)redhat.com&gt;
---
 dracut-module-setup.sh |  1 +
 kdump-lib.sh           | 48 +++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index 8d451b4..f5fce2f 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -628,6 +628,7 @@ install() {
     inst "/bin/dd" "/bin/dd"
     inst "/bin/tail" "/bin/tail"
     inst "/bin/date" "/bin/date"
+    inst "/bin/getent" "/bin/getent"
     inst "/bin/sync" "/bin/sync"
     inst "/bin/cut" "/bin/cut"
     inst "/sbin/makedumpfile" "/sbin/makedumpfile"
diff --git a/kdump-lib.sh b/kdump-lib.sh
index b886c5d..cc33e01 100755
--- a/kdump-lib.sh
+++ b/kdump-lib.sh
@@ -170,21 +170,47 @@ get_remote_host()
     echo $_config_val
 }
 
-# check the remote server ip address tpye
-is_ipv6_target()
+# Convert hostname to ip address, echo the original value if $1 is already an ip
address.
+# $1: hostname or ip address
+get_ip_address()
 {
-    local _server _server_tmp
+    local _ip_address
+
+    _ip_address=`getent ahosts $1 | head -n 1 | cut -d' ' -f1`
+    _ip_address=${_ip_address:-$1}
+    echo $_ip_address
+}
+
+# the ipv6 address has the special character colon ":", so we can pick it out.
+# we can pass a ip address, if ipv6 address, will return ipv6 address,
+# otherwise return NULL
+is_ipv6_host()
+{
+    local _addr=$(get_ip_address $1)
+    echo $_addr | grep -q ":"
+}
+
+get_network_target()
+{
+    local _target
 
     if is_ssh_dump_target; then
-        _server=`get_option_value ssh`
+        _target=`get_option_value ssh`
     elif is_nfs_dump_target; then
-        _server=`get_option_value nfs`
+        _target=`get_option_value nfs`
     fi
 
-    [ -z "$_server" ] && return 1
-    _server=`get_remote_host $_server`
-    _server_tmp=$_server
-    _server=`getent ahosts $_server | head -n 1 | cut -d' ' -f1`
-    _server=${_server:-$_server_tmp}
-    echo $_server | grep -q ":"
+    [ -z "$_target" ] && return
+
+    _target=`get_remote_host $_target`
+    echo $_target
+}
+
+# check the remote server ip address tpye
+is_ipv6_target()
+{
+    local _target=$(get_network_target)
+
+    [ -z "$_target" ] && return 1
+    echo $(is_ipv6_host $_target)
 }
-- 
1.9.3