library: eliminate insidious 'LIBPROC_HIDE_KERNEL' bug

When support for the 'LIBPROC_HIDE_KERNEL' environment
variable was introduced, a deficiency was present that
allowed any rejected proc_t (i.e. a kworker thread) to
preserve the strdup'd 'cmd' value. That residual value
would prevent stat2proc or status2proc from updating a
cmd field with the proper program name for some tasks.

This patch just ensures a proc_t is freshened whenever
it has been rejected due to an active PT->hide_kernel.

[ again thanks to Björn for initiating the extension ]

Reference(s):
. original hide_kernel implementation
commit 2a7ec67ac8
. original hide_kernel proposal
https://gitlab.com/procps-ng/procps/-/merge_requests/147

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2022-05-01 00:00:00 -05:00 committed by Craig Small
parent bad7f2a263
commit b9723148a2

View File

@ -1229,9 +1229,13 @@ static proc_t *simple_readproc(PROCTAB *restrict const PT, proc_t *restrict cons
autogroup_fill(path, p);
// openproc() ensured that a ppid will be present when needed ...
if (rc == 0)
return (PT->hide_kernel && (p->ppid == 2 || p->tid == 2)) ? NULL : p;
if (rc == 0) {
if (PT->hide_kernel && (p->ppid == 2 || p->tid == 2)) {
free_acquired(p);
return NULL;
}
return p;
}
errno = ENOMEM;
next_proc:
return NULL;