Make tmpdir removal asynchronous

https://bugs.freedesktop.org/show_bug.cgi?id=68232

Makefile.am

@@ -967,8 +967,8 @@ libsystemd_core_la_SOURCES = \
 	src/core/syscall-list.h \
 	src/core/audit-fd.c \
 	src/core/audit-fd.h \
-	src/core/sync.c \
-	src/core/sync.h
+	src/core/async.c \
+	src/core/async.h
 
 if HAVE_KMOD
 libsystemd_core_la_SOURCES += \

src/core/async.c

@@ -22,14 +22,10 @@
 #include <pthread.h>
 #include <unistd.h>
 
-#include "sync.h"
+#include "async.h"
+#include "log.h"
 
-static void *sync_thread(void *p) {
-        sync();
-        return NULL;
-}
-
-int asynchronous_sync(void) {
+int asynchronous_job(void* (*func)(void *p), void *arg) {
         pthread_attr_t a;
         pthread_t t;
         int r;
@@ -53,7 +49,7 @@ int asynchronous_sync(void) {
                 goto finish;
         }
 
-        r = pthread_create(&t, &a, sync_thread, NULL);
+        r = pthread_create(&t, &a, func, arg);
         if (r != 0) {
                 r = -r;
                 goto finish;
@@ -63,3 +59,14 @@ finish:
         pthread_attr_destroy(&a);
         return r;
 }
+
+static void *sync_thread(void *p) {
+        sync();
+        return NULL;
+}
+
+int asynchronous_sync(void) {
+        log_debug("Spawning new thread for sync");
+
+        return asynchronous_job(sync_thread, NULL);
+}

src/core/async.h

@@ -21,4 +21,5 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+int asynchronous_job(void* (*func)(void *p), void *arg);
 int asynchronous_sync(void);

src/core/execute.c

@@ -67,6 +67,7 @@
 #include "env-util.h"
 #include "fileio.h"
 #include "unit.h"
+#include "async.h"
 
 #define IDLE_TIMEOUT_USEC (5*USEC_PER_SEC)
 #define IDLE_TIMEOUT2_USEC (1*USEC_PER_SEC)
@@ -1581,6 +1582,28 @@ void exec_context_init(ExecContext *c) {
         c->timer_slack_nsec = (nsec_t) -1;
 }
 
+static void *remove_tmpdir_thread(void *p) {
+        int r;
+        _cleanup_free_ char *dirp = p;
+        char *dir;
+
+        assert(dirp);
+
+        r = rm_rf_dangerous(dirp, false, true, false);
+        dir = dirname(dirp);
+        if (r < 0)
+                log_warning("Failed to remove content of temporary directory %s: %s",
+                            dir, strerror(-r));
+        else {
+                r = rmdir(dir);
+                if (r < 0)
+                        log_warning("Failed to remove temporary directory %s: %s",
+                                    dir, strerror(-r));
+        }
+
+        return NULL;
+}
+
 void exec_context_tmp_dirs_done(ExecContext *c) {
         char* dirs[] = {c->tmp_dir ? c->tmp_dir : c->var_tmp_dir,
                         c->tmp_dir ? c->var_tmp_dir : NULL,
@@ -1588,22 +1611,8 @@ void exec_context_tmp_dirs_done(ExecContext *c) {
         char **dirp;
 
         for(dirp = dirs; *dirp; dirp++) {
-                char *dir;
-                int r;
-
-                r = rm_rf_dangerous(*dirp, false, true, false);
-                dir = dirname(*dirp);
-                if (r < 0)
-                        log_warning("Failed to remove content of temporary directory %s: %s",
-                                    dir, strerror(-r));
-                else {
-                        r = rmdir(dir);
-                        if (r < 0)
-                                log_warning("Failed to remove  temporary directory %s: %s",
-                                            dir, strerror(-r));
-                }
-
-                free(*dirp);
+                log_debug("Spawning thread to nuke %s", *dirp);
+                asynchronous_job(remove_tmpdir_thread, *dirp);
         }
 
         c->tmp_dir = c->var_tmp_dir = NULL;

src/core/job.c

@@ -35,7 +35,7 @@
 #include "log.h"
 #include "dbus-job.h"
 #include "special.h"
-#include "sync.h"
+#include "async.h"
 #include "virt.h"
 
 JobBusClient* job_bus_client_new(DBusConnection *connection, const char *name) {