sync: Add NDK sync.h and libsync

The new header provides an updated interface to libsync appropriate
for the NDK. Clients use existing syscalls where possible (e.g. poll()
instead of sync_wait()), and the remaining functions return structures
used in mainline Linux kernels rather than the Android staging sync
framework.

Over time, framework clients will be migrated to using the NDK
interface, which will eventually replace the current internal
interface. The only difference is the header will be named
<android/sync.h> in the NDK and <sync/sync.h> internally.

Bug: 35138793
Test: sync-unit-tests on bullhead
Change-Id: Ieb3649b80565393e26b604416158438d32c2a256

5 files changed, 338 insertions, 61 deletions

diff --git a/libsync/Android.bp b/libsync/Android.bp
index a4e55992c..b293da4ad 100644
--- a/libsync/Android.bp
+++ b/libsync/Android.bp
@@ -1,3 +1,17 @@
+ndk_headers {
+    name: "libsync_headers",
+    from: "include/ndk",
+    to: "android",
+    srcs: ["include/ndk/sync.h"],
+    license: "NOTICE",
+}
+
+ndk_library {
+    name: "libsync.ndk",
+    symbol_file: "libsync.map.txt",
+    first_version: "26",
+}
+
 cc_defaults {
     name: "libsync_defaults",
     srcs: ["sync.c"],
diff --git a/libsync/NOTICE b/libsync/NOTICE
new file mode 100644
index 000000000..2c8db73b0
--- /dev/null
+++ b/libsync/NOTICE
@@ -0,0 +1,190 @@
+
+   Copyright (c) 2012-2017, The Android Open Source Project
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+
+   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.
+
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
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+      outstanding shares, or (iii) beneficial ownership of such entity.
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+      "You" (or "Your") shall mean an individual or Legal Entity
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+      including but not limited to software source code, documentation
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+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
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+      "Work" shall mean the work of authorship, whether in Source or
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+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
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+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
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+      Work and such Derivative Works in Source or Object form.
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+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
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+      (d) If the Work includes a "NOTICE" text file as part of its
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+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
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+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
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+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
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+      Work (including but not limited to damages for loss of goodwill,
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+      other commercial damages or losses), even if such Contributor
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+   9. Accepting Warranty or Additional Liability. While redistributing
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+      defend, and hold each Contributor harmless for any liability
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+   END OF TERMS AND CONDITIONS
+
diff --git a/libsync/include/ndk/sync.h b/libsync/include/ndk/sync.h
new file mode 100644
index 000000000..758a10623
--- /dev/null
+++ b/libsync/include/ndk/sync.h
@@ -0,0 +1,89 @@
+/*
+ *  Copyright 2017 The Android Open Source Project
+ *
+ *  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.
+ */
+
+#ifndef ANDROID_SYNC_H
+#define ANDROID_SYNC_H
+
+#include <stdint.h>
+
+#include <linux/sync_file.h>
+
+__BEGIN_DECLS
+
+#if __ANDROID_API__ >= __ANDROID_API_O__
+
+/* Fences indicate the status of an asynchronous task. They are initially
+ * in unsignaled state (0), and make a one-time transition to either signaled
+ * (1) or error (< 0) state. A sync file is a collection of one or more fences;
+ * the sync file's status is error if any of its fences are in error state,
+ * signaled if all of the child fences are signaled, or unsignaled otherwise.
+ *
+ * Sync files are created by various device APIs in response to submitting
+ * tasks to the device. Standard file descriptor lifetime syscalls like dup()
+ * and close() are used to manage sync file lifetime.
+ *
+ * The poll(), ppoll(), or select() syscalls can be used to wait for the sync
+ * file to change status, or (with a timeout of zero) to check its status.
+ *
+ * The functions below provide a few additional sync-specific operations.
+ */
+
+/**
+ * Merge two sync files.
+ *
+ * This produces a new sync file with the given name which has the union of the
+ * two original sync file's fences; redundant fences may be removed.
+ *
+ * If one of the input sync files is signaled or invalid, then this function
+ * may behave like dup(): the new file descriptor refers to the valid/unsignaled
+ * sync file with its original name, rather than a new sync file.
+ *
+ * The original fences remain valid, and the caller is responsible for closing
+ * them.
+ */
+int32_t sync_merge(const char *name, int32_t fd1, int32_t fd2);
+
+/**
+ * Retrieve detailed information about a sync file and its fences.
+ *
+ * The returned sync_file_info must be freed by calling sync_file_info_free().
+ */
+struct sync_file_info *sync_file_info(int32_t fd);
+
+/**
+ * Get the array of fence infos from the sync file's info.
+ *
+ * The returned array is owned by the parent sync file info, and has
+ * info->num_fences entries.
+ */
+inline struct sync_fence_info *sync_get_fence_info(
+        const struct sync_file_info *info) {
+// This header should compile in C, but some C++ projects enable
+// warnings-as-error for C-style casts.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wold-style-cast"
+    return (struct sync_fence_info *)(uintptr_t)(info->sync_fence_info);
+#pragma GCC diagnostic pop
+}
+
+/** Free a struct sync_file_info structure */
+void sync_file_info_free(struct sync_file_info *info);
+
+#endif // __ANDROID_API__ >= __ANDROID_API_O__
+
+__END_DECLS
+
+#endif /* ANDROID_SYNC_H */
diff --git a/libsync/include/sync/sync.h b/libsync/include/sync/sync.h
index 50ed0ac57..8755d2b5d 100644
--- a/libsync/include/sync/sync.h
+++ b/libsync/include/sync/sync.h
@@ -19,6 +19,19 @@
 #ifndef __SYS_CORE_SYNC_H
 #define __SYS_CORE_SYNC_H
 
+/* This file contains the legacy sync interface used by Android platform and
+ * device code. The direct contents will be removed over time as code
+ * transitions to using the updated interface in ndk/sync.h. When this file is
+ * empty other than the ndk/sync.h include, that file will be renamed to
+ * replace this one.
+ *
+ * New code should continue to include this file (#include <sync/sync.h>)
+ * instead of ndk/sync.h so the eventual rename is seamless, but should only
+ * use the things declared in ndk/sync.h.
+ */
+
+#include "../ndk/sync.h"
+
 #include <sys/cdefs.h>
 #include <stdint.h>
 
@@ -90,69 +103,8 @@ struct sync_pt_info {
 #define SYNC_IOC_LEGACY_FENCE_INFO	_IOWR(SYNC_IOC_MAGIC, 2,\
 	struct sync_fence_info_data)
 
-struct sync_merge_data {
- char name[32];
- int32_t fd2;
- int32_t fence;
- uint32_t flags;
- uint32_t pad;
-};
-
-struct sync_file_info {
- char name[32];
- int32_t status;
- uint32_t flags;
- uint32_t num_fences;
- uint32_t pad;
-
- uint64_t sync_fence_info;
-};
-
-struct sync_fence_info {
- char obj_name[32];
- char driver_name[32];
- int32_t status;
- uint32_t flags;
- uint64_t timestamp_ns;
-};
-
-/**
- * Mainline API:
- *
- * Opcodes  0, 1 and 2 were burned during a API change to avoid users of the
- * old API to get weird errors when trying to handling sync_files. The API
- * change happened during the de-stage of the Sync Framework when there was
- * no upstream users available.
- */
-
-/**
- * DOC: SYNC_IOC_MERGE - merge two fences
- *
- * Takes a struct sync_merge_data.  Creates a new fence containing copies of
- * the sync_pts in both the calling fd and sync_merge_data.fd2.  Returns the
- * new fence's fd in sync_merge_data.fence
- *
- * This is the new version of the Sync API after the de-stage that happened
- * on Linux kernel 4.7.
- */
-#define SYNC_IOC_MERGE		_IOWR(SYNC_IOC_MAGIC, 3, struct sync_merge_data)
-
-/**
- * DOC: SYNC_IOC_FILE_INFO - get detailed information on a sync_file
- *
- * Takes a struct sync_file_info. If num_fences is 0, the field is updated
- * with the actual number of fences. If num_fences is > 0, the system will
- * use the pointer provided on sync_fence_info to return up to num_fences of
- * struct sync_fence_info, with detailed fence information.
- *
- * This is the new version of the Sync API after the de-stage that happened
- * on Linux kernel 4.7.
- */
-#define SYNC_IOC_FILE_INFO	_IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info)
-
 /* timeout in msecs */
 int sync_wait(int fd, int timeout);
-int sync_merge(const char *name, int fd1, int fd2);
 struct sync_fence_info_data *sync_fence_info(int fd);
 struct sync_pt_info *sync_pt_info(struct sync_fence_info_data *info,
                                   struct sync_pt_info *itr);
diff --git a/libsync/libsync.map.txt b/libsync/libsync.map.txt
new file mode 100644
index 000000000..daa28ae92
--- /dev/null
+++ b/libsync/libsync.map.txt
@@ -0,0 +1,32 @@
+#
+# Copyright 2017 The Android Open Source Project
+#
+# 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.
+#
+
+LIBSYNC {
+  global:
+    sync_merge; # introduced=26
+    sync_get_fence_info; # introduced=26
+    sync_free_fence_info; # introduced=26
+  local:
+    *;
+};
+
+LIBSYNC_PLATFORM {
+  global:
+    sync_wait;
+    sync_fence_info;
+    sync_pt_info;
+    sync_fence_info_free;
+} LIBSYNC_PLATFORM;