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-rw-r--r--src/libbasic/async.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/src/libbasic/async.c b/src/libbasic/async.c
new file mode 100644
index 0000000000..a1f163f27b
--- /dev/null
+++ b/src/libbasic/async.c
@@ -0,0 +1,94 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2013 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <pthread.h>
+#include <stddef.h>
+#include <unistd.h>
+
+#include "async.h"
+#include "fd-util.h"
+#include "log.h"
+#include "macro.h"
+#include "util.h"
+
+int asynchronous_job(void* (*func)(void *p), void *arg) {
+ pthread_attr_t a;
+ pthread_t t;
+ int r;
+
+ /* It kinda sucks that we have to resort to threads to
+ * implement an asynchronous sync(), but well, such is
+ * life.
+ *
+ * Note that issuing this command right before exiting a
+ * process will cause the process to wait for the sync() to
+ * complete. This function hence is nicely asynchronous really
+ * only in long running processes. */
+
+ r = pthread_attr_init(&a);
+ if (r > 0)
+ return -r;
+
+ r = pthread_attr_setdetachstate(&a, PTHREAD_CREATE_DETACHED);
+ if (r > 0)
+ goto finish;
+
+ r = pthread_create(&t, &a, func, arg);
+
+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);
+}
+
+static void *close_thread(void *p) {
+ assert_se(close_nointr(PTR_TO_FD(p)) != -EBADF);
+ return NULL;
+}
+
+int asynchronous_close(int fd) {
+ int r;
+
+ /* This is supposed to behave similar to safe_close(), but
+ * actually invoke close() asynchronously, so that it will
+ * never block. Ideally the kernel would have an API for this,
+ * but it doesn't, so we work around it, and hide this as a
+ * far away as we can. */
+
+ if (fd >= 0) {
+ PROTECT_ERRNO;
+
+ r = asynchronous_job(close_thread, FD_TO_PTR(fd));
+ if (r < 0)
+ assert_se(close_nointr(fd) != -EBADF);
+ }
+
+ return -1;
+}