#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/resource.h>
+#include <linux/notifier.h>
+#include <linux/suspend.h>
#include <asm/uaccess.h>
extern int max_threads;
char **argv;
char **envp;
struct key *ring;
- int wait;
+ enum umh_wait wait;
int retval;
struct file *stdin;
void (*cleanup)(char **argv, char **envp);
sub_info->retval = ret;
}
- if (sub_info->wait < 0)
+ if (sub_info->wait == UMH_NO_WAIT)
call_usermodehelper_freeinfo(sub_info);
else
complete(sub_info->complete);
struct subprocess_info *sub_info =
container_of(work, struct subprocess_info, work);
pid_t pid;
- int wait = sub_info->wait;
+ enum umh_wait wait = sub_info->wait;
/* CLONE_VFORK: wait until the usermode helper has execve'd
* successfully We need the data structures to stay around
* until that is done. */
- if (wait)
+ if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT)
pid = kernel_thread(wait_for_helper, sub_info,
CLONE_FS | CLONE_FILES | SIGCHLD);
else
pid = kernel_thread(____call_usermodehelper, sub_info,
CLONE_VFORK | SIGCHLD);
- if (wait < 0)
- return;
+ switch (wait) {
+ case UMH_NO_WAIT:
+ break;
- if (pid < 0) {
+ case UMH_WAIT_PROC:
+ if (pid > 0)
+ break;
sub_info->retval = pid;
+ /* FALLTHROUGH */
+
+ case UMH_WAIT_EXEC:
complete(sub_info->complete);
- } else if (!wait)
- complete(sub_info->complete);
+ }
}
+#ifdef CONFIG_PM
+/*
+ * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
+ * (used for preventing user land processes from being created after the user
+ * land has been frozen during a system-wide hibernation or suspend operation).
+ */
+static int usermodehelper_disabled;
+
+/* Number of helpers running */
+static atomic_t running_helpers = ATOMIC_INIT(0);
+
+/*
+ * Wait queue head used by usermodehelper_pm_callback() to wait for all running
+ * helpers to finish.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
+
+/*
+ * Time to wait for running_helpers to become zero before the setting of
+ * usermodehelper_disabled in usermodehelper_pm_callback() fails
+ */
+#define RUNNING_HELPERS_TIMEOUT (5 * HZ)
+
+static int usermodehelper_pm_callback(struct notifier_block *nfb,
+ unsigned long action,
+ void *ignored)
+{
+ long retval;
+
+ switch (action) {
+ case PM_HIBERNATION_PREPARE:
+ case PM_SUSPEND_PREPARE:
+ usermodehelper_disabled = 1;
+ smp_mb();
+ /*
+ * From now on call_usermodehelper_exec() won't start any new
+ * helpers, so it is sufficient if running_helpers turns out to
+ * be zero at one point (it may be increased later, but that
+ * doesn't matter).
+ */
+ retval = wait_event_timeout(running_helpers_waitq,
+ atomic_read(&running_helpers) == 0,
+ RUNNING_HELPERS_TIMEOUT);
+ if (retval) {
+ return NOTIFY_OK;
+ } else {
+ usermodehelper_disabled = 0;
+ return NOTIFY_BAD;
+ }
+ case PM_POST_HIBERNATION:
+ case PM_POST_SUSPEND:
+ usermodehelper_disabled = 0;
+ return NOTIFY_OK;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static void helper_lock(void)
+{
+ atomic_inc(&running_helpers);
+ smp_mb__after_atomic_inc();
+}
+
+static void helper_unlock(void)
+{
+ if (atomic_dec_and_test(&running_helpers))
+ wake_up(&running_helpers_waitq);
+}
+
+static void register_pm_notifier_callback(void)
+{
+ pm_notifier(usermodehelper_pm_callback, 0);
+}
+#else /* CONFIG_PM */
+#define usermodehelper_disabled 0
+
+static inline void helper_lock(void) {}
+static inline void helper_unlock(void) {}
+static inline void register_pm_notifier_callback(void) {}
+#endif /* CONFIG_PM */
+
/**
* call_usermodehelper_setup - prepare to call a usermode helper
- * @path - path to usermode executable
- * @argv - arg vector for process
- * @envp - environment for process
+ * @path: path to usermode executable
+ * @argv: arg vector for process
+ * @envp: environment for process
*
- * Returns either NULL on allocation failure, or a subprocess_info
+ * Returns either %NULL on allocation failure, or a subprocess_info
* structure. This should be passed to call_usermodehelper_exec to
* exec the process and free the structure.
*/
* (ie. it runs with full root capabilities).
*/
int call_usermodehelper_exec(struct subprocess_info *sub_info,
- int wait)
+ enum umh_wait wait)
{
DECLARE_COMPLETION_ONSTACK(done);
int retval;
+ helper_lock();
if (sub_info->path[0] == '\0') {
retval = 0;
goto out;
}
- if (!khelper_wq) {
+ if (!khelper_wq || usermodehelper_disabled) {
retval = -EBUSY;
goto out;
}
sub_info->wait = wait;
queue_work(khelper_wq, &sub_info->work);
- if (wait < 0) /* task has freed sub_info */
+ if (wait == UMH_NO_WAIT) /* task has freed sub_info */
return 0;
wait_for_completion(&done);
retval = sub_info->retval;
out:
call_usermodehelper_freeinfo(sub_info);
+ helper_unlock();
return retval;
}
EXPORT_SYMBOL(call_usermodehelper_exec);
if (ret < 0)
goto out;
- return call_usermodehelper_exec(sub_info, 1);
+ return call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
out:
call_usermodehelper_freeinfo(sub_info);
{
khelper_wq = create_singlethread_workqueue("khelper");
BUG_ON(!khelper_wq);
+ register_pm_notifier_callback();
}
git.openpandora.org / pandora-kernel.git / blobdiff