lmkd: Introduce liblmkd_utils for communicating with lmkd process
(cherry pick from commit 0f1005180513e880bf7c90a3f2c2bf1a36aa1406)
A number of tools and tests require communication with lmkd.
In order to avoid code duplication liblmkd_utils implements
functions commonly used when interacting with lmkd process.
Isolate communication protocol details into lmkd.h
Bug: 63631020
Change-Id: Id840983d55b7db60013d52dee0c3187943811822
Merged-In: Id840983d55b7db60013d52dee0c3187943811822
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
diff --git a/lmkd/liblmkd_utils.c b/lmkd/liblmkd_utils.c
new file mode 100644
index 0000000..fa3b7a9
--- /dev/null
+++ b/lmkd/liblmkd_utils.c
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2018 Google, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/cdefs.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <liblmkd_utils.h>
+#include <cutils/sockets.h>
+
+int lmkd_connect() {
+ return socket_local_client("lmkd",
+ ANDROID_SOCKET_NAMESPACE_RESERVED,
+ SOCK_SEQPACKET);
+}
+
+int lmkd_register_proc(int sock, struct lmk_procprio *params) {
+ LMKD_CTRL_PACKET packet;
+ size_t size;
+ int ret;
+
+ size = lmkd_pack_set_procprio(packet, params);
+ ret = TEMP_FAILURE_RETRY(write(sock, packet, size));
+
+ return (ret < 0) ? -1 : 0;
+}
+
+int create_memcg(uid_t uid, pid_t pid) {
+ char buf[256];
+ int tasks_file;
+ int written;
+
+ snprintf(buf, sizeof(buf), "/dev/memcg/apps/uid_%u", uid);
+ if (mkdir(buf, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH) < 0 &&
+ errno != EEXIST) {
+ return -1;
+ }
+
+ snprintf(buf, sizeof(buf), "/dev/memcg/apps/uid_%u/pid_%u", uid, pid);
+ if (mkdir(buf, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH) < 0 &&
+ errno != EEXIST) {
+ return -1;
+ }
+
+ snprintf(buf, sizeof(buf), "/dev/memcg/apps/uid_%u/pid_%u/tasks", uid, pid);
+ tasks_file = open(buf, O_WRONLY);
+ if (tasks_file < 0) {
+ return -2;
+ }
+ written = snprintf(buf, sizeof(buf), "%u", pid);
+ if (__predict_false(written >= (int)sizeof(buf))) {
+ written = sizeof(buf) - 1;
+ }
+ written = TEMP_FAILURE_RETRY(write(tasks_file, buf, written));
+ close(tasks_file);
+
+ return (written < 0) ? -3 : 0;
+}
+