cgroups: don't fail parsing when colon not found

The format of cpuacct.stat seems to not always have a colon as separator.

It appears to *not* have the colon at least on debian's kernel 3.2.41 and
3.2.35, as well as on RHEL6 with 2.6.32. All of them have decent support for
cgroups/lxc, and the cgroups plugin fails to work with them without this patch.

Also, looking at other implementations shows that they *don't* expect a colon:
https://bitbucket.org/dotcloud/liblxcstats/src/2558b4fbbf589c609895b0badbfc7d413466d716/probes/cpuacct.c?at=default#cl-71
https://github.com/BrightcoveOS/Diamond/blob/master/src/collectors/cpuacct_cgroup/cpuacct_cgroup.py#L55

diff --git a/src/cgroups.c b/src/cgroups.c
index ffb1740..061aa32 100644 (file)
--- a/src/cgroups.c
+++ b/src/cgroups.c
@@ -111,6 +111,11 @@ static int read_cpuacct_procs (const char *dirname, char const *cgroup_name,
                 *
                 *   user: 12345
                 *   system: 23456
+                *
+                * Or:
+                *
+                *   user 12345
+                *   system 23456
                 */
                strstripnewline (buf);
                numfields = strsplit (buf, fields, STATIC_ARRAY_SIZE (fields));
@@ -122,10 +127,9 @@ static int read_cpuacct_procs (const char *dirname, char const *cgroup_name,
                if (key_len < 2)
                        continue;
 
-               /* Strip colon off the first column */
-               if (key[key_len - 1] != ':')
-                       continue;
-               key[key_len - 1] = 0;
+               /* Strip colon off the first column, if found */
+               if (key[key_len - 1] == ':')
+                       key[key_len - 1] = 0;
 
                status = parse_value (fields[1], &value, DS_TYPE_DERIVE);
                if (status != 0)