adb: create shell protocol class (take 2).

Adds a new class ShellProtocol to help read and write data with
`adb shell`. This will allow splitting streams and sending out-of-band
data such as exit codes.

Nothing uses the new class yet except the unit tests.

This is the second attempt at this CL, the first is at
http://r.android.com/169600. The problems was using sighandler_t
which is not available on mac. sig_t is used instead which is available
due to _GNU_SOURCE being defined in Android.mk, which causes
_BSD_SOURCE -> __USE_BSD -> sig_t to be defined. Nothing else has been
changed from the original CL.

Bug: http://b/23030641
Change-Id: I7bd7f5a82ad811fbca7a3eee1236d2c55ae57c48

1 files changed, 192 insertions, 0 deletions

diff --git a/shell_service_protocol_test.cpp b/shell_service_protocol_test.cpp
new file mode 100644
index 0000000..85b2f91
--- /dev/null
+++ b/shell_service_protocol_test.cpp
@@ -0,0 +1,192 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include "shell_service.h"
+
+#include <gtest/gtest.h>
+
+#include <signal.h>
+#include <string.h>
+
+#include "sysdeps.h"
+
+class ShellProtocolTest : public ::testing::Test {
+  public:
+    static void SetUpTestCase() {
+#if !defined(_WIN32)
+        // This is normally done in main.cpp.
+        saved_sigpipe_handler_ = signal(SIGPIPE, SIG_IGN);
+#endif
+    }
+
+    static void TearDownTestCase() {
+#if !defined(_WIN32)
+        signal(SIGPIPE, saved_sigpipe_handler_);
+#endif
+    }
+
+    // Initializes the socketpair and ShellProtocols needed for testing.
+    void SetUp() {
+        int fds[2];
+        ASSERT_EQ(0, adb_socketpair(fds));
+        read_fd_ = fds[0];
+        write_fd_ = fds[1];
+
+        write_protocol_ = new ShellProtocol(write_fd_);
+        ASSERT_TRUE(write_protocol_ != nullptr);
+
+        read_protocol_ = new ShellProtocol(read_fd_);
+        ASSERT_TRUE(read_protocol_ != nullptr);
+    }
+
+    // Cleans up FDs and ShellProtocols. If an FD is closed manually during a
+    // test, set it to -1 to prevent TearDown() trying to close it again.
+    void TearDown() {
+        for (int fd : {read_fd_, write_fd_}) {
+            if (fd >= 0) {
+                adb_close(fd);
+            }
+        }
+        for (ShellProtocol* protocol : {read_protocol_, write_protocol_}) {
+            if (protocol) {
+                delete protocol;
+            }
+        }
+    }
+
+    // Fakes the buffer size so we can test filling buffers.
+    void SetReadDataCapacity(size_t size) {
+        read_protocol_->buffer_end_ = read_protocol_->data() + size;
+    }
+
+    static sig_t saved_sigpipe_handler_;
+
+    int read_fd_ = -1, write_fd_ = -1;
+    ShellProtocol *read_protocol_ = nullptr, *write_protocol_ = nullptr;
+};
+
+sig_t ShellProtocolTest::saved_sigpipe_handler_ = nullptr;
+
+namespace {
+
+// Returns true if the packet contains the given values.
+bool PacketEquals(const ShellProtocol* protocol, ShellProtocol::Id id,
+                    const void* data, size_t data_length) {
+    return (protocol->id() == id &&
+            protocol->data_length() == data_length &&
+            !memcmp(data, protocol->data(), data_length));
+}
+
+}  // namespace
+
+// Tests data that can fit in a single packet.
+TEST_F(ShellProtocolTest, FullPacket) {
+    ShellProtocol::Id id = ShellProtocol::kIdStdout;
+    char data[] = "abc 123 \0\r\n";
+
+    memcpy(write_protocol_->data(), data, sizeof(data));
+    ASSERT_TRUE(write_protocol_->Write(id, sizeof(data)));
+
+    ASSERT_TRUE(read_protocol_->Read());
+    ASSERT_TRUE(PacketEquals(read_protocol_, id, data, sizeof(data)));
+}
+
+// Tests data that has to be read multiple times due to smaller read buffer.
+TEST_F(ShellProtocolTest, ReadBufferOverflow) {
+    ShellProtocol::Id id = ShellProtocol::kIdStdin;
+
+    memcpy(write_protocol_->data(), "1234567890", 10);
+    ASSERT_TRUE(write_protocol_->Write(id, 10));
+
+    SetReadDataCapacity(4);
+    ASSERT_TRUE(read_protocol_->Read());
+    ASSERT_TRUE(PacketEquals(read_protocol_, id, "1234", 4));
+    ASSERT_TRUE(read_protocol_->Read());
+    ASSERT_TRUE(PacketEquals(read_protocol_, id, "5678", 4));
+    ASSERT_TRUE(read_protocol_->Read());
+    ASSERT_TRUE(PacketEquals(read_protocol_, id, "90", 2));
+}
+
+// Tests a zero length packet.
+TEST_F(ShellProtocolTest, ZeroLengthPacket) {
+    ShellProtocol::Id id = ShellProtocol::kIdStderr;
+
+    ASSERT_TRUE(write_protocol_->Write(id, 0));
+    ASSERT_TRUE(read_protocol_->Read());
+    ASSERT_TRUE(PacketEquals(read_protocol_, id, nullptr, 0));
+}
+
+// Tests exit code packets.
+TEST_F(ShellProtocolTest, ExitCodePacket) {
+    write_protocol_->data()[0] = 20;
+    ASSERT_TRUE(write_protocol_->Write(ShellProtocol::kIdExit, 1));
+
+    ASSERT_TRUE(read_protocol_->Read());
+    ASSERT_EQ(ShellProtocol::kIdExit, read_protocol_->id());
+    ASSERT_EQ(20, read_protocol_->data()[0]);
+}
+
+// Tests writing to a closed pipe.
+TEST_F(ShellProtocolTest, WriteToClosedPipeFail) {
+    adb_close(read_fd_);
+    read_fd_ = -1;
+
+    ASSERT_FALSE(write_protocol_->Write(ShellProtocol::kIdStdout, 0));
+}
+
+// Tests writing to a closed FD.
+TEST_F(ShellProtocolTest, WriteToClosedFdFail) {
+    adb_close(write_fd_);
+    write_fd_ = -1;
+
+    ASSERT_FALSE(write_protocol_->Write(ShellProtocol::kIdStdout, 0));
+}
+
+// Tests reading from a closed pipe.
+TEST_F(ShellProtocolTest, ReadFromClosedPipeFail) {
+    adb_close(write_fd_);
+    write_fd_ = -1;
+
+    ASSERT_FALSE(read_protocol_->Read());
+}
+
+// Tests reading from a closed FD.
+TEST_F(ShellProtocolTest, ReadFromClosedFdFail) {
+    adb_close(read_fd_);
+    read_fd_ = -1;
+
+    ASSERT_FALSE(read_protocol_->Read());
+}
+
+// Tests reading from a closed pipe that has a packet waiting. This checks that
+// even if the pipe closes before we can fully read its contents we will still
+// be able to access the last packets.
+TEST_F(ShellProtocolTest, ReadPacketFromClosedPipe) {
+    ShellProtocol::Id id = ShellProtocol::kIdStdout;
+    char data[] = "foo bar";
+
+    memcpy(write_protocol_->data(), data, sizeof(data));
+    ASSERT_TRUE(write_protocol_->Write(id, sizeof(data)));
+    adb_close(write_fd_);
+    write_fd_ = -1;
+
+    // First read should grab the packet.
+    ASSERT_TRUE(read_protocol_->Read());
+    ASSERT_TRUE(PacketEquals(read_protocol_, id, data, sizeof(data)));
+
+    // Second read should fail.
+    ASSERT_FALSE(read_protocol_->Read());
+}