third_party: Add the libsync library from Android

third_party/libsync/sync.c

+/*
+ *  sync.c
+ *
+ *   Copyright 2012 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 <fcntl.h>
+#include <malloc.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <linux/sync.h>
+#include <linux/sw_sync.h>
+
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+int sync_wait(int fd, int timeout)
+{
+    __s32 to = timeout;
+
+    return ioctl(fd, SYNC_IOC_WAIT, &to);
+}
+
+int sync_merge(const char *name, int fd1, int fd2)
+{
+    struct sync_merge_data data;
+    int err;
+
+    data.fd2 = fd2;
+    strlcpy(data.name, name, sizeof(data.name));
+
+    err = ioctl(fd1, SYNC_IOC_MERGE, &data);
+    if (err < 0)
+        return err;
+
+    return data.fence;
+}
+
+struct sync_fence_info_data *sync_fence_info(int fd)
+{
+    struct sync_fence_info_data *info;
+    int err;
+
+    info = malloc(4096);
+    if (info == NULL)
+        return NULL;
+
+    info->len = 4096;
+    err = ioctl(fd, SYNC_IOC_FENCE_INFO, info);
+    if (err < 0) {
+        free(info);
+        return NULL;
+    }
+
+    return info;
+}
+
+struct sync_pt_info *sync_pt_info(struct sync_fence_info_data *info,
+                                  struct sync_pt_info *itr)
+{
+    if (itr == NULL)
+        itr = (struct sync_pt_info *) info->pt_info;
+    else
+        itr = (struct sync_pt_info *) ((__u8 *)itr + itr->len);
+
+    if ((__u8 *)itr - (__u8 *)info >= (int)info->len)
+        return NULL;
+
+    return itr;
+}
+
+void sync_fence_info_free(struct sync_fence_info_data *info)
+{
+    free(info);
+}
+
+
+int sw_sync_timeline_create(void)
+{
+    return open("/dev/sw_sync", O_RDWR);
+}
+
+int sw_sync_timeline_inc(int fd, unsigned count)
+{
+    __u32 arg = count;
+
+    return ioctl(fd, SW_SYNC_IOC_INC, &arg);
+}
+
+int sw_sync_fence_create(int fd, const char *name, unsigned value)
+{
+    struct sw_sync_create_fence_data data;
+    int err;
+
+    data.value = value;
+    strlcpy(data.name, name, sizeof(data.name));
+
+    err = ioctl(fd, SW_SYNC_IOC_CREATE_FENCE, &data);
+    if (err < 0)
+        return err;
+
+    return data.fence;
+}