Kernel version >= 2.6.27 check

Jeff Schroeder wrote:
> Awesome tool! I learned about this from the LWN article and
> immediately (stupidly) tried it out on a centos 5 host. Here is a
> patch to add a kernel version check.

This is a nice fix, but the version check should be done against
the proc data being used (which is not necessarily that of the
local kernel).  This required moving kernel_version_check to
after where the src data is read.

capture

@@ -4,7 +4,7 @@
 # capture a memory data snapshot with realtime priority
 mkdir -p $1
 chrt --fifo 99 \
-  cp -a --parents /proc/[0-9]*/{smaps,cmdline,stat} /proc/meminfo $1
+  cp -a --parents /proc/[0-9]*/{smaps,cmdline,stat} /proc/meminfo /proc/version $1
 
 # build a compressed tarball of snapshot
 cd $1/proc

smem

@@ -33,6 +33,8 @@ class procdata(object):
         return self._readlines('%s/smaps' % pid)
     def memdata(self):
         return self._readlines('meminfo')
+    def version(self):
+        return self._readlines('version')[0]
     def pidname(self, pid):
         l = self._read('%d/stat' % pid)
         return l[l.find('(') + 1: l.find(')')]
@@ -552,7 +554,7 @@ def showbar(l, columns, sort):
     pylab.show()
 
 def kernel_version_check():
-    kernel_release = os.uname()[2].split('-')[0]
+    kernel_release = src.version().split()[2].split('-')[0]
     if kernel_release < "2.6.27":
         name = os.path.basename(sys.argv[0])
         sys.stderr.write(name + " requires a kernel >= 2.6.27\n")
@@ -606,7 +608,6 @@ parser.add_option("-S", "--source", type="str",
                   help="/proc data source")
 
 
-kernel_version_check()
 defaults = {}
 parser.set_defaults(**defaults)
 (options, args) = parser.parse_args()
@@ -616,6 +617,8 @@ try:
 except:
     src = procdata(options.source)
 
+kernel_version_check()
+
 try:
     if options.mappings:
         showmaps()