1 files changed, 465 insertions, 0 deletions
diff --git a/libs/utils/Pipe.cpp b/libs/utils/Pipe.cpp
new file mode 100644
index 0000000..613906b
--- /dev/null
+++ b/libs/utils/Pipe.cpp
@@ -0,0 +1,465 @@
+/*
+ * Copyright (C) 2005 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.
+ */
+
+//
+// Unidirectional pipe.
+//
+
+#include <utils/Pipe.h>
+#include <utils/Log.h>
+
+#if defined(HAVE_WIN32_IPC)
+# include <windows.h>
+#else
+# include <fcntl.h>
+# include <unistd.h>
+# include <errno.h>
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+#include <string.h>
+
+using namespace android;
+
+const unsigned long kInvalidHandle = (unsigned long) -1;
+
+
+/*
+ * Constructor.  Do little.
+ */
+Pipe::Pipe(void)
+    : mReadNonBlocking(false), mReadHandle(kInvalidHandle),
+      mWriteHandle(kInvalidHandle)
+{
+}
+
+/*
+ * Destructor.  Use the system-appropriate close call.
+ */
+Pipe::~Pipe(void)
+{
+#if defined(HAVE_WIN32_IPC)
+    if (mReadHandle != kInvalidHandle) {
+        if (!CloseHandle((HANDLE)mReadHandle))
+            LOG(LOG_WARN, "pipe", "failed closing read handle (%ld)\n",
+                mReadHandle);
+    }
+    if (mWriteHandle != kInvalidHandle) {
+        FlushFileBuffers((HANDLE)mWriteHandle);
+        if (!CloseHandle((HANDLE)mWriteHandle))
+            LOG(LOG_WARN, "pipe", "failed closing write handle (%ld)\n",
+                mWriteHandle);
+    }
+#else
+    if (mReadHandle != kInvalidHandle) {
+        if (close((int) mReadHandle) != 0)
+            LOG(LOG_WARN, "pipe", "failed closing read fd (%d)\n",
+                (int) mReadHandle);
+    }
+    if (mWriteHandle != kInvalidHandle) {
+        if (close((int) mWriteHandle) != 0)
+            LOG(LOG_WARN, "pipe", "failed closing write fd (%d)\n",
+                (int) mWriteHandle);
+    }
+#endif
+}
+
+/*
+ * Create the pipe.
+ *
+ * Use the POSIX stuff for everything but Windows.
+ */
+bool Pipe::create(void)
+{
+    assert(mReadHandle == kInvalidHandle);
+    assert(mWriteHandle == kInvalidHandle);
+
+#if defined(HAVE_WIN32_IPC)
+    /* we use this across processes, so they need to be inheritable */
+    HANDLE handles[2];
+    SECURITY_ATTRIBUTES saAttr;
+
+    saAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
+    saAttr.bInheritHandle = TRUE;
+    saAttr.lpSecurityDescriptor = NULL;
+
+    if (!CreatePipe(&handles[0], &handles[1], &saAttr, 0)) {
+        LOG(LOG_ERROR, "pipe", "unable to create pipe\n");
+        return false;
+    }
+    mReadHandle = (unsigned long) handles[0];
+    mWriteHandle = (unsigned long) handles[1];
+    return true;
+#else
+    int fds[2];
+
+    if (pipe(fds) != 0) {
+        LOG(LOG_ERROR, "pipe", "unable to create pipe\n");
+        return false;
+    }
+    mReadHandle = fds[0];
+    mWriteHandle = fds[1];
+    return true;
+#endif
+}
+
+/*
+ * Create a "half pipe".  Please, no Segway riding.
+ */
+bool Pipe::createReader(unsigned long handle)
+{
+    mReadHandle = handle;
+    assert(mWriteHandle == kInvalidHandle);
+    return true;
+}
+
+/*
+ * Create a "half pipe" for writing.
+ */
+bool Pipe::createWriter(unsigned long handle)
+{
+    mWriteHandle = handle;
+    assert(mReadHandle == kInvalidHandle);
+    return true;
+}
+
+/*
+ * Return "true" if create() has been called successfully.
+ */
+bool Pipe::isCreated(void)
+{
+    // one or the other should be open
+    return (mReadHandle != kInvalidHandle || mWriteHandle != kInvalidHandle);
+}
+
+
+/*
+ * Read data from the pipe.
+ *
+ * For Linux and Darwin, just call read().  For Windows, implement
+ * non-blocking reads by calling PeekNamedPipe first.
+ */
+int Pipe::read(void* buf, int count)
+{
+    assert(mReadHandle != kInvalidHandle);
+
+#if defined(HAVE_WIN32_IPC)
+    DWORD totalBytesAvail = count;
+    DWORD bytesRead;
+
+    if (mReadNonBlocking) {
+        // use PeekNamedPipe to adjust read count expectations
+        if (!PeekNamedPipe((HANDLE) mReadHandle, NULL, 0, NULL,
+                &totalBytesAvail, NULL))
+        {
+            LOG(LOG_ERROR, "pipe", "PeekNamedPipe failed\n");
+            return -1;
+        }
+
+        if (totalBytesAvail == 0)
+            return 0;
+    }
+
+    if (!ReadFile((HANDLE) mReadHandle, buf, totalBytesAvail, &bytesRead,
+            NULL))
+    {
+        DWORD err = GetLastError();
+        if (err == ERROR_HANDLE_EOF || err == ERROR_BROKEN_PIPE)
+            return 0;
+        LOG(LOG_ERROR, "pipe", "ReadFile failed (err=%ld)\n", err);
+        return -1;
+    }
+
+    return (int) bytesRead;
+#else
+    int cc;
+    cc = ::read(mReadHandle, buf, count);
+    if (cc < 0 && errno == EAGAIN)
+        return 0;
+    return cc;
+#endif
+}
+
+/*
+ * Write data to the pipe.
+ *
+ * POSIX systems are trivial, Windows uses a different call and doesn't
+ * handle non-blocking writes.
+ *
+ * If we add non-blocking support here, we probably want to make it an
+ * all-or-nothing write.
+ *
+ * DO NOT use LOG() here, we could be writing a log message.
+ */
+int Pipe::write(const void* buf, int count)
+{
+    assert(mWriteHandle != kInvalidHandle);
+
+#if defined(HAVE_WIN32_IPC)
+    DWORD bytesWritten;
+
+    if (mWriteNonBlocking) {
+        // BUG: can't use PeekNamedPipe() to get the amount of space
+        // left.  Looks like we need to use "overlapped I/O" functions.
+        // I just don't care that much.
+    }
+
+    if (!WriteFile((HANDLE) mWriteHandle, buf, count, &bytesWritten, NULL)) {
+        // can't LOG, use stderr
+        fprintf(stderr, "WriteFile failed (err=%ld)\n", GetLastError());
+        return -1;
+    }
+
+    return (int) bytesWritten;
+#else
+    int cc;
+    cc = ::write(mWriteHandle, buf, count);
+    if (cc < 0 && errno == EAGAIN)
+        return 0;
+    return cc;
+#endif
+}
+
+/*
+ * Figure out if there is data available on the read fd.
+ *
+ * We return "true" on error because we want the caller to try to read
+ * from the pipe.  They'll notice the read failure and do something
+ * appropriate.
+ */
+bool Pipe::readReady(void)
+{
+    assert(mReadHandle != kInvalidHandle);
+
+#if defined(HAVE_WIN32_IPC)
+    DWORD totalBytesAvail;
+
+    if (!PeekNamedPipe((HANDLE) mReadHandle, NULL, 0, NULL,
+            &totalBytesAvail, NULL))
+    {
+        LOG(LOG_ERROR, "pipe", "PeekNamedPipe failed\n");
+        return true;
+    }
+
+    return (totalBytesAvail != 0);
+#else
+    errno = 0;
+    fd_set readfds;
+    struct timeval tv = { 0, 0 };
+    int cc;
+
+    FD_ZERO(&readfds);
+    FD_SET(mReadHandle, &readfds);
+
+    cc = select(mReadHandle+1, &readfds, NULL, NULL, &tv);
+    if (cc < 0) {
+        LOG(LOG_ERROR, "pipe", "select() failed\n");
+        return true;
+    } else if (cc == 0) {
+        /* timed out, nothing available */
+        return false;
+    } else if (cc == 1) {
+        /* our fd is ready */
+        return true;
+    } else {
+        LOG(LOG_ERROR, "pipe", "HUH? select() returned > 1\n");
+        return true;
+    }
+#endif
+}
+
+/*
+ * Enable or disable non-blocking mode for the read descriptor.
+ *
+ * NOTE: the calls succeed under Mac OS X, but the pipe doesn't appear to
+ * actually be in non-blocking mode.  If this matters -- i.e. you're not
+ * using a select() call -- put a call to readReady() in front of the
+ * ::read() call, with a PIPE_NONBLOCK_BROKEN #ifdef in the Makefile for
+ * Darwin.
+ */
+bool Pipe::setReadNonBlocking(bool val)
+{
+    assert(mReadHandle != kInvalidHandle);
+
+#if defined(HAVE_WIN32_IPC)
+    // nothing to do
+#else
+    int flags;
+
+    if (fcntl(mReadHandle, F_GETFL, &flags) == -1) {
+        LOG(LOG_ERROR, "pipe", "couldn't get flags for pipe read fd\n");
+        return false;
+    }
+    if (val)
+        flags |= O_NONBLOCK;
+    else
+        flags &= ~(O_NONBLOCK);
+    if (fcntl(mReadHandle, F_SETFL, &flags) == -1) {
+        LOG(LOG_ERROR, "pipe", "couldn't set flags for pipe read fd\n");
+        return false;
+    }
+#endif
+
+    mReadNonBlocking = val;
+    return true;
+}
+
+/*
+ * Enable or disable non-blocking mode for the write descriptor.
+ *
+ * As with setReadNonBlocking(), this does not work on the Mac.
+ */
+bool Pipe::setWriteNonBlocking(bool val)
+{
+    assert(mWriteHandle != kInvalidHandle);
+
+#if defined(HAVE_WIN32_IPC)
+    // nothing to do
+#else
+    int flags;
+
+    if (fcntl(mWriteHandle, F_GETFL, &flags) == -1) {
+        LOG(LOG_WARN, "pipe",
+            "Warning: couldn't get flags for pipe write fd (errno=%d)\n",
+            errno);
+        return false;
+    }
+    if (val)
+        flags |= O_NONBLOCK;
+    else
+        flags &= ~(O_NONBLOCK);
+    if (fcntl(mWriteHandle, F_SETFL, &flags) == -1) {
+        LOG(LOG_WARN, "pipe",
+            "Warning: couldn't set flags for pipe write fd (errno=%d)\n",
+            errno);
+        return false;
+    }
+#endif
+
+    mWriteNonBlocking = val;
+    return true;
+}
+
+/*
+ * Specify whether a file descriptor can be inherited by a child process.
+ * Under Linux this means setting the close-on-exec flag, under Windows
+ * this is SetHandleInformation(HANDLE_FLAG_INHERIT).
+ */
+bool Pipe::disallowReadInherit(void)
+{
+    if (mReadHandle == kInvalidHandle)
+        return false;
+
+#if defined(HAVE_WIN32_IPC)
+    if (SetHandleInformation((HANDLE) mReadHandle, HANDLE_FLAG_INHERIT, 0) == 0)
+        return false;
+#else
+    if (fcntl((int) mReadHandle, F_SETFD, FD_CLOEXEC) != 0)
+        return false;
+#endif
+    return true;
+}
+bool Pipe::disallowWriteInherit(void)
+{
+    if (mWriteHandle == kInvalidHandle)
+        return false;
+
+#if defined(HAVE_WIN32_IPC)
+    if (SetHandleInformation((HANDLE) mWriteHandle, HANDLE_FLAG_INHERIT, 0) == 0)
+        return false;
+#else
+    if (fcntl((int) mWriteHandle, F_SETFD, FD_CLOEXEC) != 0)
+        return false;
+#endif
+    return true;
+}
+
+/*
+ * Close read descriptor.
+ */
+bool Pipe::closeRead(void)
+{
+    if (mReadHandle == kInvalidHandle)
+        return false;
+
+#if defined(HAVE_WIN32_IPC)
+    if (mReadHandle != kInvalidHandle) {
+        if (!CloseHandle((HANDLE)mReadHandle)) {
+            LOG(LOG_WARN, "pipe", "failed closing read handle\n");
+            return false;
+        }
+    }
+#else
+    if (mReadHandle != kInvalidHandle) {
+        if (close((int) mReadHandle) != 0) {
+            LOG(LOG_WARN, "pipe", "failed closing read fd\n");
+            return false;
+        }
+    }
+#endif
+    mReadHandle = kInvalidHandle;
+    return true;
+}
+
+/*
+ * Close write descriptor.
+ */
+bool Pipe::closeWrite(void)
+{
+    if (mWriteHandle == kInvalidHandle)
+        return false;
+
+#if defined(HAVE_WIN32_IPC)
+    if (mWriteHandle != kInvalidHandle) {
+        if (!CloseHandle((HANDLE)mWriteHandle)) {
+            LOG(LOG_WARN, "pipe", "failed closing write handle\n");
+            return false;
+        }
+    }
+#else
+    if (mWriteHandle != kInvalidHandle) {
+        if (close((int) mWriteHandle) != 0) {
+            LOG(LOG_WARN, "pipe", "failed closing write fd\n");
+            return false;
+        }
+    }
+#endif
+    mWriteHandle = kInvalidHandle;
+    return true;
+}
+
+/*
+ * Get the read handle.
+ */
+unsigned long Pipe::getReadHandle(void)
+{
+    assert(mReadHandle != kInvalidHandle);
+
+    return mReadHandle;
+}
+
+/*
+ * Get the write handle.
+ */
+unsigned long Pipe::getWriteHandle(void)
+{
+    assert(mWriteHandle != kInvalidHandle);
+
+    return mWriteHandle;
+}
+