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

[Ray Strode <halfline src gnome org>]

commit 924a1fc94005a90a375da9a1eee03778118429c4
Author: Ray Strode <rstrode redhat com>
Date:   Fri Jul 24 14:41:48 2009 -0400

    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.

 common/gdm-common.c             |   48 ++++++++++++++++++++++++++++++++++++--
 common/gdm-common.h             |    2 +
 daemon/gdm-session-worker-job.c |    2 +-
 3 files changed, 48 insertions(+), 4 deletions(-)
---
diff --git a/common/gdm-common.c b/common/gdm-common.c
index de80700..7a4e26d 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 8faeda5..06300c8 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,
diff --git a/daemon/gdm-session-worker-job.c b/daemon/gdm-session-worker-job.c
index 50bf4c0..c13a0a2 100644
--- a/daemon/gdm-session-worker-job.c
+++ b/daemon/gdm-session-worker-job.c
@@ -262,7 +262,7 @@ session_worker_job_died (GdmSessionWorkerJob *session_worker_job)
         int exit_status;
 
         g_debug ("GdmSessionWorkerJob: Waiting on process %d", session_worker_job->priv->pid);
-        exit_status = gdm_wait_on_pid (session_worker_job->priv->pid);
+        exit_status = gdm_wait_on_and_kill_pid (session_worker_job->priv->pid, 3);
 
         if (WIFEXITED (exit_status) && (WEXITSTATUS (exit_status) != 0)) {
                 g_debug ("GdmSessionWorkerJob: Wait on child process failed");