Check the kernel feature

From: Daniel Lezcano <daniel.lezcano@free.fr>

The virtual devices are automatically destroyed when the network namespace
dies for the kernel version >= 2.6.29. Until this version the network devices
have to be destroyed by lxc. This modification checks the version of the
kernel to make lxc to destroy the network devices or not.

Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

1 files changed, 94 insertions, 1 deletions

diff --git a/config/acinclude.m4 b/config/acinclude.m4
index 02629ce..a36fdf3 100644
--- a/config/acinclude.m4
+++ b/config/acinclude.m4
@@ -41,4 +41,97 @@ AC_DEFUN([AS_AC_EXPAND],
     dnl restore prefix and exec_prefix
     prefix=$prefix_save
     exec_prefix=$exec_prefix_save
-])
\ No newline at end of file
+])
+
+dnl Available from the GNU Autoconf Macro Archive at:
+dnl http://www.gnu.org/software/ac-archive/htmldoc/ax_compare_version.html
+AC_DEFUN([AX_COMPARE_VERSION], [
+# Used to indicate true or false condition
+ax_compare_version=false
+	  # Convert the two version strings to be compared into a format that
+  # allows a simple string comparison.  The end result is that a version
+  # string of the form 1.12.5-r617 will be converted to the form
+  # 0001001200050617.  In other words, each number is zero padded to four
+  # digits, and non digits are removed.
+  AS_VAR_PUSHDEF([A],[ax_compare_version_A])
+  A=`echo "$1" | sed -e 's/\([[0-9]]*\)/Z\1Z/g' \
+                     -e 's/Z\([[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/[[^0-9]]//g'`
+
+  AS_VAR_PUSHDEF([B],[ax_compare_version_B])
+  B=`echo "$3" | sed -e 's/\([[0-9]]*\)/Z\1Z/g' \
+                     -e 's/Z\([[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/Z\([[0-9]][[0-9]][[0-9]]\)Z/Z0\1Z/g' \
+                     -e 's/[[^0-9]]//g'`
+
+  dnl # In the case of le, ge, lt, and gt, the strings are sorted as necessary
+  dnl # then the first line is used to determine if the condition is true.
+  dnl # The sed right after the echo is to remove any indented white space.
+  m4_case(m4_tolower($2),
+  [lt],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort -r | sed "s/x${A}/false/;s/x${B}/true/;1q"`
+  ],
+  [gt],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort | sed "s/x${A}/false/;s/x${B}/true/;1q"`
+  ],
+  [le],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort | sed "s/x${A}/true/;s/x${B}/false/;1q"`
+  ],
+  [ge],[
+    ax_compare_version=`echo "x$A
+x$B" | sed 's/^ *//' | sort -r | sed "s/x${A}/true/;s/x${B}/false/;1q"`
+  ],[
+    dnl Split the operator from the subversion count if present.
+    m4_bmatch(m4_substr($2,2),
+    [0],[
+      # A count of zero means use the length of the shorter version.
+      # Determine the number of characters in A and B.
+      ax_compare_version_len_A=`echo "$A" | awk '{print(length)}'`
+      ax_compare_version_len_B=`echo "$B" | awk '{print(length)}'`
+ 
+      # Set A to no more than B's length and B to no more than A's length.
+      A=`echo "$A" | sed "s/\(.\{$ax_compare_version_len_B\}\).*/\1/"`
+      B=`echo "$B" | sed "s/\(.\{$ax_compare_version_len_A\}\).*/\1/"`
+    ],
+    [[0-9]+],[
+      # A count greater than zero means use only that many subversions
+      A=`echo "$A" | sed "s/\(\([[0-9]]\{4\}\)\{m4_substr($2,2)\}\).*/\1/"`
+      B=`echo "$B" | sed "s/\(\([[0-9]]\{4\}\)\{m4_substr($2,2)\}\).*/\1/"`
+    ],
+    [.+],[
+      AC_WARNING(
+        [illegal OP numeric parameter: $2])
+    ],[])
+
+    # Pad zeros at end of numbers to make same length.
+    ax_compare_version_tmp_A="$A`echo $B | sed 's/./0/g'`"
+    B="$B`echo $A | sed 's/./0/g'`"
+    A="$ax_compare_version_tmp_A"
+
+    # Check for equality or inequality as necessary.
+    m4_case(m4_tolower(m4_substr($2,0,2)),
+    [eq],[
+      test "x$A" = "x$B" && ax_compare_version=true
+    ],
+    [ne],[
+      test "x$A" != "x$B" && ax_compare_version=true
+    ],[
+      AC_WARNING([illegal OP parameter: $2])
+    ])
+  ])
+
+  AS_VAR_POPDEF([A])dnl
+  AS_VAR_POPDEF([B])dnl
+
+  dnl # Execute ACTION-IF-TRUE / ACTION-IF-FALSE.
+  if test "$ax_compare_version" = "true" ; then
+    m4_ifvaln([$4],[$4],[:])dnl
+    m4_ifvaln([$5],[else $5])dnl
+  fi
+]) dnl AX_COMPARE_VERSION