David Pursell | 4f344bb | 2015-08-28 15:08:49 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2015 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
David Pursell | d0df2dd | 2015-08-31 15:36:18 -0700 | [diff] [blame] | 17 | // This file contains classes and functionality to launch shell subprocesses |
| 18 | // in adbd and communicate between those subprocesses and the adb client. |
| 19 | // |
| 20 | // The main features exposed here are: |
| 21 | // 1. A ShellPacket class to wrap data in a simple protocol. Both adbd and |
| 22 | // the adb client use this class to transmit data between them. |
| 23 | // 2. Functions to launch a subprocess on the adbd side. |
| 24 | |
David Pursell | 4f344bb | 2015-08-28 15:08:49 -0700 | [diff] [blame] | 25 | #ifndef SHELL_SERVICE_H_ |
| 26 | #define SHELL_SERVICE_H_ |
| 27 | |
David Pursell | d0df2dd | 2015-08-31 15:36:18 -0700 | [diff] [blame] | 28 | #include <stdint.h> |
| 29 | |
| 30 | #include <base/macros.h> |
| 31 | |
| 32 | #include "adb.h" |
| 33 | |
| 34 | // Class to send and receive shell protocol packets. |
| 35 | // |
| 36 | // To keep things simple and predictable, reads and writes block until an entire |
| 37 | // packet is complete. |
| 38 | // |
| 39 | // Example: read raw data from |fd| and send it in a packet. |
| 40 | // ShellProtocol* p = new ShellProtocol(protocol_fd); |
| 41 | // int len = adb_read(stdout_fd, p->data(), p->data_capacity()); |
| 42 | // packet->WritePacket(ShellProtocol::kIdStdout, len); |
| 43 | // |
| 44 | // Example: read a packet and print it to |stdout|. |
| 45 | // ShellProtocol* p = new ShellProtocol(protocol_fd); |
| 46 | // if (p->ReadPacket() && p->id() == kIdStdout) { |
| 47 | // fwrite(p->data(), 1, p->data_length(), stdout); |
| 48 | // } |
| 49 | class ShellProtocol { |
| 50 | public: |
| 51 | // This is an unscoped enum to make it easier to compare against raw bytes. |
| 52 | enum Id : uint8_t { |
David Pursell | 3fe11f6 | 2015-10-06 15:30:03 -0700 | [diff] [blame] | 53 | kIdStdin = 0, |
David Pursell | d0df2dd | 2015-08-31 15:36:18 -0700 | [diff] [blame] | 54 | kIdStdout = 1, |
| 55 | kIdStderr = 2, |
David Pursell | 3fe11f6 | 2015-10-06 15:30:03 -0700 | [diff] [blame] | 56 | kIdExit = 3, |
Elliott Hughes | a826579 | 2015-11-03 11:18:40 -0800 | [diff] [blame] | 57 | |
| 58 | // Close subprocess stdin if possible. |
| 59 | kIdCloseStdin = 4, |
| 60 | |
| 61 | // Window size change (an ASCII version of struct winsize). |
| 62 | kIdWindowSizeChange = 5, |
| 63 | |
| 64 | // Indicates an invalid or unknown packet. |
| 65 | kIdInvalid = 255, |
David Pursell | d0df2dd | 2015-08-31 15:36:18 -0700 | [diff] [blame] | 66 | }; |
| 67 | |
| 68 | // ShellPackets will probably be too large to allocate on the stack so they |
| 69 | // should be dynamically allocated on the heap instead. |
| 70 | // |
| 71 | // |fd| is an open file descriptor to be used to send or receive packets. |
| 72 | explicit ShellProtocol(int fd); |
| 73 | virtual ~ShellProtocol(); |
| 74 | |
| 75 | // Returns a pointer to the data buffer. |
| 76 | const char* data() const { return buffer_ + kHeaderSize; } |
| 77 | char* data() { return buffer_ + kHeaderSize; } |
| 78 | |
| 79 | // Returns the total capacity of the data buffer. |
| 80 | size_t data_capacity() const { return buffer_end_ - data(); } |
| 81 | |
| 82 | // Reads a packet from the FD. |
| 83 | // |
| 84 | // If a packet is too big to fit in the buffer then Read() will split the |
| 85 | // packet across multiple calls. For example, reading a 50-byte packet into |
| 86 | // a 20-byte buffer would read 20 bytes, 20 bytes, then 10 bytes. |
| 87 | // |
| 88 | // Returns false if the FD closed or errored. |
| 89 | bool Read(); |
| 90 | |
| 91 | // Returns the ID of the packet in the buffer. |
| 92 | int id() const { return buffer_[0]; } |
| 93 | |
| 94 | // Returns the number of bytes that have been read into the data buffer. |
| 95 | size_t data_length() const { return data_length_; } |
| 96 | |
| 97 | // Writes the packet currently in the buffer to the FD. |
| 98 | // |
| 99 | // Returns false if the FD closed or errored. |
| 100 | bool Write(Id id, size_t length); |
| 101 | |
| 102 | private: |
| 103 | // Packets support 4-byte lengths. |
| 104 | typedef uint32_t length_t; |
| 105 | |
| 106 | enum { |
| 107 | // It's OK if MAX_PAYLOAD doesn't match on the sending and receiving |
| 108 | // end, reading will split larger packets into multiple smaller ones. |
| 109 | kBufferSize = MAX_PAYLOAD, |
| 110 | |
| 111 | // Header is 1 byte ID + 4 bytes length. |
| 112 | kHeaderSize = sizeof(Id) + sizeof(length_t) |
| 113 | }; |
| 114 | |
| 115 | int fd_; |
| 116 | char buffer_[kBufferSize]; |
| 117 | size_t data_length_ = 0, bytes_left_ = 0; |
| 118 | |
| 119 | // We need to be able to modify this value for testing purposes, but it |
| 120 | // will stay constant during actual program use. |
| 121 | char* buffer_end_ = buffer_ + sizeof(buffer_); |
| 122 | |
| 123 | friend class ShellProtocolTest; |
| 124 | |
| 125 | DISALLOW_COPY_AND_ASSIGN(ShellProtocol); |
| 126 | }; |
| 127 | |
David Pursell | 4f344bb | 2015-08-28 15:08:49 -0700 | [diff] [blame] | 128 | #if !ADB_HOST |
| 129 | |
| 130 | enum class SubprocessType { |
| 131 | kPty, |
| 132 | kRaw, |
| 133 | }; |
| 134 | |
David Pursell | 8da19a4 | 2015-08-31 10:42:13 -0700 | [diff] [blame] | 135 | enum class SubprocessProtocol { |
| 136 | kNone, |
| 137 | kShell, |
| 138 | }; |
| 139 | |
David Pursell | 4f344bb | 2015-08-28 15:08:49 -0700 | [diff] [blame] | 140 | // Forks and starts a new shell subprocess. If |name| is empty an interactive |
| 141 | // shell is started, otherwise |name| is executed non-interactively. |
| 142 | // |
| 143 | // Returns an open FD connected to the subprocess or -1 on failure. |
Elliott Hughes | ff44456 | 2015-11-16 10:55:34 -0800 | [diff] [blame] | 144 | int StartSubprocess(const char* name, const char* terminal_type, |
| 145 | SubprocessType type, SubprocessProtocol protocol); |
David Pursell | 4f344bb | 2015-08-28 15:08:49 -0700 | [diff] [blame] | 146 | |
| 147 | #endif // !ADB_HOST |
| 148 | |
| 149 | #endif // SHELL_SERVICE_H_ |