library: adapt readproc for the latest lxc conventions

The merge request shown below prompted (thankfully) an
examination of our lxc containers logic in readproc.c.

As it turns out, the lxc folks changed that eyecatcher
used to identify containers within a task cgroup file.

So this patch, with little extra cost, will enable the
libprocps lxc_containers() guy to handle both strings.

[ additionally, I was shocked to find lxc allows the ]
[ eyecatcher to be changed at ./configure time. such ]
[ a provision has always existed. unfortunately, the ]
[ changed value was only available to root, assuming ]
[ one wished to tackle that undocumented liblxc api. ]

Reference(s):
. what prompted lxc support reevaluation
https://gitlab.com/procps-ng/procps/merge_requests/82
. original lxc support introduced
commit 0557504f9c

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2019-01-10 00:00:00 -06:00 committed by Craig Small
parent 96d59cbf46
commit 288d759b8b

View File

@ -926,22 +926,28 @@ static char *lxc_containers (const char *path) {
1:cpuset,cpu,cpuacct,devices,freezer,net_cls,blkio,perf_event,net_prio:/lxc/lxc-P
*/
if (file2str(path, "cgroup", &ub) > 0) {
static const char lxc_delm[] = "/lxc/";
/* ouch, next two defaults could be changed at lxc ./configure time
( and a changed 'lxc.cgroup.pattern' is only available to root ) */
static const char lxc_delm1[] = "/lxc/"; // thru lxc-3.0.3
static const char lxc_delm2[] = "/lxc.payload/"; // with lxc-3.1.0
const char *delim;
char *p1;
if ((p1 = strstr(ub.buf, lxc_delm))) {
if ((p1 = strstr(ub.buf, (delim = lxc_delm1)))
|| ((p1 = strstr(ub.buf, (delim = lxc_delm2))))) {
static struct lxc_ele {
struct lxc_ele *next;
char *name;
} *anchor = NULL;
struct lxc_ele *ele = anchor;
int delim_len = strlen(delim);
char *p2;
if ((p2 = strchr(p1, '\n'))) // isolate a controller's line
*p2 = '\0';
do { // deal with nested containers
p2 = p1 + (sizeof(lxc_delm)-1);
p1 = strstr(p2, lxc_delm);
p2 = p1 + (delim_len);
p1 = strstr(p2, delim);
} while (p1);
if ((p1 = strchr(p2, '/'))) // isolate name only substring
*p1 = '\0';