Split payload application code into a subdirectory.
This patch splits from the main libupdate_engine code the part that
is strictly used to download and apply a payload into a new static
library, moving the code to subdirectories. The new library is divided
in two subdirectories: common/ and payload_consumer/, and should not
depend on other update_engine files outside those two subdirectories.
The main difference between those two is that the common/ tools are more
generic and not tied to the payload consumer process, but otherwise they
are both compiled together.
There are still dependencies from the new libpayload_consumer library
into the main directory files and DBus generated files. Those will be
addressed in follow up CLs.
Bug: 25197634
Test: FEATURES=test emerge-link update_engine; `mm` on Brillo.
Change-Id: Id8d0204ea573627e6e26ca9ea17b9592ca95bc23
diff --git a/payload_consumer/file_descriptor.h b/payload_consumer/file_descriptor.h
new file mode 100644
index 0000000..3c15415
--- /dev/null
+++ b/payload_consumer/file_descriptor.h
@@ -0,0 +1,141 @@
+//
+// Copyright (C) 2012 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 UPDATE_ENGINE_PAYLOAD_CONSUMER_FILE_DESCRIPTOR_H_
+#define UPDATE_ENGINE_PAYLOAD_CONSUMER_FILE_DESCRIPTOR_H_
+
+#include <errno.h>
+#include <memory>
+#include <sys/types.h>
+
+#include <base/logging.h>
+
+// Abstraction for managing opening, reading, writing and closing of file
+// descriptors. This includes an abstract class and one standard implementation
+// based on POSIX system calls.
+//
+// TODO(garnold) this class is modeled after (and augments the functionality of)
+// the FileWriter class; ultimately, the latter should be replaced by the former
+// throughout the codebase. A few deviations from the original FileWriter:
+//
+// * Providing two flavors of Open()
+//
+// * A FileDescriptor is reusable and can be used to read/write multiple files
+// as long as open/close preconditions are respected.
+//
+// * Write() returns the number of bytes written: this appears to be more useful
+// for clients, who may wish to retry or otherwise do something useful with
+// the remaining data that was not written.
+//
+// * Provides a Reset() method, which will force to abandon a currently open
+// file descriptor and allow opening another file, without necessarily
+// properly closing the old one. This may be useful in cases where a "closer"
+// class does not care whether Close() was successful, but may need to reuse
+// the same file descriptor again.
+
+namespace chromeos_update_engine {
+
+class FileDescriptor;
+using FileDescriptorPtr = std::shared_ptr<FileDescriptor>;
+
+// An abstract class defining the file descriptor API.
+class FileDescriptor {
+ public:
+ FileDescriptor() {}
+ virtual ~FileDescriptor() {}
+
+ // Opens a file descriptor. The descriptor must be in the closed state prior
+ // to this call. Returns true on success, false otherwise. Specific
+ // implementations may set errno accordingly.
+ virtual bool Open(const char* path, int flags, mode_t mode) = 0;
+ virtual bool Open(const char* path, int flags) = 0;
+
+ // Reads from a file descriptor up to a given count. The descriptor must be
+ // open prior to this call. Returns the number of bytes read, or -1 on error.
+ // Specific implementations may set errno accordingly.
+ virtual ssize_t Read(void* buf, size_t count) = 0;
+
+ // Writes to a file descriptor. The descriptor must be open prior to this
+ // call. Returns the number of bytes written, or -1 if an error occurred and
+ // no bytes were written. Specific implementations may set errno accordingly.
+ virtual ssize_t Write(const void* buf, size_t count) = 0;
+
+ // Seeks to an offset. Returns the resulting offset location as measured in
+ // bytes from the beginning. On error, return -1. Specific implementations
+ // may set errno accordingly.
+ virtual off64_t Seek(off64_t offset, int whence) = 0;
+
+ // Runs a ioctl() on the file descriptor if supported. Returns whether
+ // the operation is supported. The |request| can be one of BLKDISCARD,
+ // BLKZEROOUT and BLKSECDISCARD to discard, write zeros or securely discard
+ // the blocks. These ioctls accept a range of bytes (|start| and |length|)
+ // over which they perform the operation. The return value from the ioctl is
+ // stored in |result|.
+ virtual bool BlkIoctl(int request,
+ uint64_t start,
+ uint64_t length,
+ int* result) = 0;
+
+ // Closes a file descriptor. The descriptor must be open prior to this call.
+ // Returns true on success, false otherwise. Specific implementations may set
+ // errno accordingly.
+ virtual bool Close() = 0;
+
+ // Resets the file descriptor, abandoning a currently open file and returning
+ // the descriptor to the closed state.
+ virtual void Reset() = 0;
+
+ // Indicates whether or not an implementation sets meaningful errno.
+ virtual bool IsSettingErrno() = 0;
+
+ // Indicates whether the descriptor is currently open.
+ virtual bool IsOpen() = 0;
+
+ private:
+ DISALLOW_COPY_AND_ASSIGN(FileDescriptor);
+};
+
+// A simple EINTR-immune wrapper implementation around standard system calls.
+class EintrSafeFileDescriptor : public FileDescriptor {
+ public:
+ EintrSafeFileDescriptor() : fd_(-1) {}
+
+ // Interface methods.
+ bool Open(const char* path, int flags, mode_t mode) override;
+ bool Open(const char* path, int flags) override;
+ ssize_t Read(void* buf, size_t count) override;
+ ssize_t Write(const void* buf, size_t count) override;
+ off64_t Seek(off64_t offset, int whence) override;
+ bool BlkIoctl(int request,
+ uint64_t start,
+ uint64_t length,
+ int* result) override;
+ bool Close() override;
+ void Reset() override;
+ bool IsSettingErrno() override {
+ return true;
+ }
+ bool IsOpen() override {
+ return (fd_ >= 0);
+ }
+
+ protected:
+ int fd_;
+};
+
+} // namespace chromeos_update_engine
+
+#endif // UPDATE_ENGINE_PAYLOAD_CONSUMER_FILE_DESCRIPTOR_H_