daemon: kill stuck processes if they don't die on term

Some PAM modules are really slow to shut down.
We need to handle them being slow to shut down better,
(by not blocking login on them shutting down etc), but
in the mean time force them to die immediately.

2 files changed, 47 insertions, 3 deletions

diff --git a/common/gdm-common.c b/common/gdm-common.c
index de807000..7a4e26d8 100644
--- a/common/gdm-common.c
+++ b/common/gdm-common.c
@@ -93,13 +93,25 @@ gdm_get_pwent_for_name (const char     *name,
 }
 
 int
-gdm_wait_on_pid (int pid)
+gdm_wait_on_and_kill_pid (int pid,
+                          int timeout)
 {
         int status;
-
+        int ret;
+        int num_tries;
+        int flags;
+
+        if (timeout > 0) {
+                flags = WNOHANG;
+                num_tries = 10 * timeout;
+        } else {
+                flags = 0;
+                num_tries = 0;
+        }
  wait_again:
         errno = 0;
-        if (waitpid (pid, &status, 0) < 0) {
+        ret = waitpid (pid, &status, flags);
+        if (ret < 0) {
                 if (errno == EINTR) {
                         goto wait_again;
                 } else if (errno == ECHILD) {
@@ -107,6 +119,30 @@ gdm_wait_on_pid (int pid)
                 } else {
                         g_debug ("GdmCommon: waitpid () should not fail");
                 }
+        } else if (ret == 0) {
+                num_tries--;
+
+                if (num_tries > 0) {
+                        g_usleep (G_USEC_PER_SEC / 10);
+                } else {
+                        char *path;
+                        char *command;
+
+                        path = g_strdup_printf ("/proc/%ld/cmdline", (long) pid);
+                        if (g_file_get_contents (path, &command, NULL, NULL)) {;
+                                g_debug ("GdmCommon: process (pid:%d, command '%s') isn't dying, now killing it.",
+                                         (int) pid, command);
+                                g_free (command);
+                        } else {
+                                g_debug ("GdmCommon: process (pid:%d) isn't dying, now killing it.",
+                                         (int) pid);
+                        }
+                        g_free (path);
+
+                        kill (pid, SIGKILL);
+                        flags = 0;
+                }
+                goto wait_again;
         }
 
         g_debug ("GdmCommon: process (pid:%d) done (%s:%d)",
@@ -122,6 +158,12 @@ gdm_wait_on_pid (int pid)
 }
 
 int
+gdm_wait_on_pid (int pid)
+{
+    return gdm_wait_on_and_kill_pid (pid, 0);
+}
+
+int
 gdm_signal_pid (int pid,
                 int signal)
 {
diff --git a/common/gdm-common.h b/common/gdm-common.h
index 8faeda5c..06300c8f 100644
--- a/common/gdm-common.h
+++ b/common/gdm-common.h
@@ -34,6 +34,8 @@ gboolean       gdm_is_version_unstable            (void);
 void           gdm_set_fatal_warnings_if_unstable (void);
 
 int            gdm_wait_on_pid           (int pid);
+int            gdm_wait_on_and_kill_pid  (int pid,
+                                          int timeout);
 int            gdm_signal_pid            (int pid,
                                           int signal);
 gboolean       gdm_get_pwent_for_name    (const char     *name,