编译Adb源码（VS2012)

--- a replacement for aproto ------------------------------------------- When it comes down to it, aproto's primary purpose is to forward various streams between the host computer and client device (in either direction). This replacement further simplifies the concept, reducing the protocol to an extremely straightforward model optimized to accomplish the forwarding of these streams and removing additional state or complexity. The host side becomes a simple comms bridge with no "UI", which will be used by either commandline or interactive tools to communicate with a device or emulator that is connected to the bridge. The protocol is designed to be straightforward and well-defined enough that if it needs to be reimplemented in another environment (Java perhaps), there should not problems ensuring perfect interoperability. The protocol discards the layering aproto has and should allow the implementation to be much more robust. --- protocol overview and basics --------------------------------------- The transport layer deals in "messages", which consist of a 24 byte header followed (optionally) by a payload. The header consists of 6 32 bit words which are sent across the wire in little endian format. struct message { unsigned command; /* command identifier constant */ unsigned arg0; /* first argument */ unsigned arg1; /* second argument */ unsigned data_length; /* length of payload (0 is allowed) */ unsigned data_crc32; /* crc32 of data payload */ unsigned magic; /* command ^ 0xffffffff */ }; Receipt of an invalid message header, corrupt message payload, or an unrecognized command MUST result in the closing of the remote connection. The protocol depends on shared state and any break in the message stream will result in state getting out of sync. The following sections describe the six defined message types in detail. Their format is COMMAND(arg0, arg1, payload) where the payload is represented by a quoted string or an empty string if none should be sent. The identifiers "local-id" and "remote-id" are always relative to the *sender* of the message, so for a receiver, the meanings are effectively reversed. --- CONNECT(version, maxdata, "system-identity-string") ---------------- The CONNECT message establishes the presence of a remote system. The version is used to ensure protocol compatibility and maxdata declares the maximum message body size that the remote system is willing to accept. Currently, version=0x01000000 and maxdata=4096 Both sides send a CONNECT message when the connection between them is established. Until a CONNECT message is received no other messages may be sent. Any messages received before a CONNECT message MUST be ignored. If a CONNECT message is received with an unknown version or insufficiently large maxdata value, the connection with the other side must be closed. The system identity string should be "<systemtype>:<serialno>:<banner>" where systemtype is "bootloader", "device", or "host", serialno is some kind of unique ID (or empty), and banner is a human-readable version or identifier string (informational only). --- OPEN(local-id, 0, "destination") ----------------------------------- The OPEN message informs the recipient that the sender has a stream identified by local-id that it wishes to connect to the named destination in the message payload. The local-id may not be zero. The OPEN message MUST result in either a READY message indicating that the connection has been established (and identifying the other end) or a CLOSE message, indicating failure. An OPEN message also implies a READY message sent at the same time. Common destination naming conventions include: * "tcp:<host>:<port>" - host may be omitted to indicate localhost * "udp:<host>:<port>" - host may be omitted to indicate localhost * "local-dgram:<identifier>" * "local-stream:<identifier>" * "shell" - local shell service * "upload" - service for pushing files across (like aproto's /sync) * "fs-bridge" - FUSE protocol filesystem bridge --- READY(local-id, remote-id, "") ------------------------------------- The READY message informs the recipient that the sender's stream identified by local-id is ready for write messages and that it is connected to the recipient's stream identified by remote-id. Neither the local-id nor the remote-id may be zero. A READY message containing a remote-id which does not map to an open stream on the recipient's side is ignored. The stream may have been closed while this message was in-flight. The local-id is ignored on all but the first READY message (where it is used to establish the connection). Nonetheless, the local-id MUST not change on later READY messages sent to the same stream. --- WRITE(0, remote-id, "data") ---------------------------------------- The WRITE message sends data to the recipient's stream identified by remote-id. The payload MUST be <= maxdata in length. A WRITE message containing a remote-id which does not map to an open stream on the recipient's side is ignored. The stream may have been closed while this message was in-flight. A WRITE message may not be sent until a READY message is received. Once a WRITE message is sent, an additional WRITE message may not be sent until another READY message has been received. Recipients of a WRITE message that is in violation of this requirement will CLOSE the connection. --- CLOSE(local-id, remote-id, "") ------------------------------------- The CLOSE message informs recipient that the connection between the sender's stream (local-id) and the recipient's stream (remote-id) is broken. The remote-id MUST not be zero, but the local-id MAY be zero if this CLOSE indicates a failed OPEN. A CLOSE message containing a remote-id which does not map to an open stream on the recipient's side is ignored. The stream may have already been closed by the recipient while this message was in-flight. The recipient should not respond to a CLOSE message in any way. The recipient should cancel pending WRITEs or CLOSEs, but this is not a requirement, since they will be ignored. --- SYNC(online, sequence, "") ----------------------------------------- The SYNC message is used by the io pump to make sure that stale outbound messages are discarded when the connection to the remote side is broken. It is only used internally to the bridge and never valid to send across the wire. * when the connection to the remote side goes offline, the io pump sends a SYNC(0, 0) and starts discarding all messages * when the connection to the remote side is established, the io pump sends a SYNC(1, token) and continues to discard messages * when the io pump receives a matching SYNC(1, token), it once again starts accepting messages to forward to the remote side --- message command constants ------------------------------------------ #define A_SYNC 0x434e5953 #define A_CNXN 0x4e584e43 #define A_OPEN 0x4e45504f #define A_OKAY 0x59414b4f #define A_CLSE 0x45534c43 #define A_WRTE 0x45545257 --- implementation details --------------------------------------------- The core of the bridge program will use three threads. One thread will be a select/epoll loop to handle io between various inbound and outbound connections and the connection to the remote side. The remote side connection will be implemented as two threads (one for reading, one for writing) and a datagram socketpair to provide the channel between the main select/epoll thread and the remote connection threadpair. The reason for this is that for usb connections, the kernel interface on linux and osx does not allow you to do meaningful nonblocking IO. The endian swapping for the message headers will happen (as needed) in the remote connection threadpair and that the rest of the program will always treat message header values as native-endian. The bridge program