init

include/android_stub/cutils/native_handle.h

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+/*
+ * Copyright (C) 2009 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 NATIVE_HANDLE_H_
+#define NATIVE_HANDLE_H_
+
+#include <stdalign.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define NATIVE_HANDLE_MAX_FDS 1024
+#define NATIVE_HANDLE_MAX_INTS 1024
+
+/* Declare a char array for use with native_handle_init */
+#define NATIVE_HANDLE_DECLARE_STORAGE(name, maxFds, maxInts) \
+    alignas(native_handle_t) char (name)[                            \
+      sizeof(native_handle_t) + sizeof(int) * ((maxFds) + (maxInts))]
+
+typedef struct native_handle
+{
+    int version;        /* sizeof(native_handle_t) */
+    int numFds;         /* number of file-descriptors at &data[0] */
+    int numInts;        /* number of ints at &data[numFds] */
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wzero-length-array"
+#endif
+    int data[0];        /* numFds + numInts ints */
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+} native_handle_t;
+
+typedef const native_handle_t* buffer_handle_t;
+
+/*
+ * Closes the file descriptors contained in this native_handle_t, which may
+ * either be untagged or tagged for ownership by this native_handle_t via
+ * native_handle_set_tag(). Mixing untagged and tagged fds in the same
+ * native_handle_t is not permitted and triggers an fdsan exception, but
+ * native_handle_set_fdsan_tag() can be used to bring consistency if this is
+ * intentional.
+ *
+ * If it's known that fds are tagged, prefer native_handle_close_with_tag() for
+ * better safety.
+ *
+ * return 0 on success, or a negative error code on failure
+ */
+int native_handle_close(const native_handle_t* h);
+
+/*
+ * Equivalent to native_handle_close(), but throws an fdsan exception if the fds
+ * are untagged. Use if it's known that the fds in this native_handle_t were
+ * previously tagged via native_handle_set_tag().
+ */
+int native_handle_close_with_tag(const native_handle_t* h);
+
+/*
+ * Initializes a native_handle_t from storage.  storage must be declared with
+ * NATIVE_HANDLE_DECLARE_STORAGE.  numFds and numInts must not respectively
+ * exceed maxFds and maxInts used to declare the storage.
+ */
+native_handle_t* native_handle_init(char* storage, int numFds, int numInts);
+
+/*
+ * Creates a native_handle_t and initializes it. Must be destroyed with
+ * native_handle_delete(). Note that numFds must be <= NATIVE_HANDLE_MAX_FDS,
+ * numInts must be <= NATIVE_HANDLE_MAX_INTS, and both must be >= 0.
+ */
+native_handle_t* native_handle_create(int numFds, int numInts);
+
+/*
+ * Updates the fdsan tag for any file descriptors contained in the supplied
+ * handle to indicate that they are owned by this handle and should only be
+ * closed via native_handle_close()/native_handle_close_with_tag(). Each fd in
+ * the handle must have a tag of either 0 (unset) or the tag associated with
+ * this handle, otherwise an fdsan exception will be triggered.
+ */
+void native_handle_set_fdsan_tag(const native_handle_t* handle);
+
+/*
+ * Clears the fdsan tag for any file descriptors contained in the supplied
+ * native_handle_t. Use if this native_handle_t is giving up ownership of its
+ * fds, but the fdsan tags were previously set. Each fd in the handle must have
+ * a tag of either 0 (unset) or the tag associated with this handle, otherwise
+ * an fdsan exception will be triggered.
+ */
+void native_handle_unset_fdsan_tag(const native_handle_t* handle);
+
+/*
+ * Creates a native_handle_t and initializes it from another native_handle_t.
+ * Must be destroyed with native_handle_delete().
+ */
+native_handle_t* native_handle_clone(const native_handle_t* handle);
+
+/*
+ * Frees a native_handle_t allocated with native_handle_create().
+ * This ONLY frees the memory allocated for the native_handle_t, but doesn't
+ * close the file descriptors; which can be achieved with native_handle_close().
+ *
+ * return 0 on success, or a negative error code on failure
+ */
+int native_handle_delete(native_handle_t* h);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NATIVE_HANDLE_H_ */