orphanskill: log command line arguments of the terminated process

Closes: rpm-software-management#1255
Closes: rpm-software-management#1268

mock/integration-tests/daemontest.c

@@ -8,7 +8,7 @@
  *      INFO: mock.py version 0.8.0 starting...
  *      State Changed: start
  *      State Changed: init
- *      WARNING: Process ID 12180 still running in chroot. Killing...
+ *      WARNING: Leftover process 1331205 is being killed with signal 15: /builddir/a.out
  *
  */
 

mock/py/mockbuild/util.py

@@ -157,6 +157,20 @@ def file_dev_ino(path):
     return file_dev_ino(path1) == file_dev_ino(path2)
 
 
+def get_pid_cmdline(pid):
+    """
+    For given PID return the command-line arguments from /proc/PID/cmdline
+    """
+    cmd_file = f"/proc/{pid}/cmdline"
+    try:
+        with open(cmd_file, "rb") as cmdline_file:
+            cmdline = cmdline_file.read().decode('utf-8').split('\0')
+            cmdline.pop()  # last string is always empty in 0-terminated file
+            return ' '.join([shlex.quote(x) for x in cmdline])
+    except OSError as e:
+        return f"ERROR: Can not read {pid} file {e}"
+
+
 @traceLog()
 def orphansKill(rootToKill, manual_forced=False):
     """
@@ -176,8 +190,9 @@ def orphansKill(rootToKill, manual_forced=False):
                 try:
                     root = os.readlink("/proc/%s/root" % fn)
                     if compare_two_paths_cached(root, rootToKill, path_cache):
-                        getLog().warning("Process ID %s still running in chroot. Killing with %s...", fn, killsig)
                         pid = int(fn, 10)
+                        getLog().warning("Leftover process %s is being killed with signal %s: %s",
+                                         pid, killsig, get_pid_cmdline(pid))
                         os.kill(pid, killsig)
                         os.waitpid(pid, 0)
                 except OSError:

releng/release-notes-next/better-orphankill-report.feature

@@ -0,0 +1,5 @@
+The automatic killing feature for orphan processes within the chroot environment
+[was][PR#1255] [improved][PR#1268] to also provide the user with information
+about the command-line arguments of the terminated process:
+
+`WARNING: Leftover process 1331205 is being killed with signal 15: daemon --with-arg`