system/FileDescriptor: new wrapper class for a file descriptor

1 files changed, 219 insertions, 0 deletions

diff --git a/src/system/FileDescriptor.cxx b/src/system/FileDescriptor.cxx
new file mode 100644
index 000000000..946493329
--- /dev/null
+++ b/src/system/FileDescriptor.cxx
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2012-2015 Max Kellermann <max@duempel.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "FileDescriptor.hxx"
+
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#ifdef HAVE_POSIX
+#include <poll.h>
+#endif
+
+#ifdef USE_EVENTFD
+#include <sys/eventfd.h>
+#endif
+
+#ifdef USE_SIGNALFD
+#include <sys/signalfd.h>
+#endif
+
+#ifdef HAVE_INOTIFY_INIT
+#include <sys/inotify.h>
+#endif
+
+#ifndef O_NOCTTY
+#define O_NOCTTY 0
+#endif
+
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+
+bool
+FileDescriptor::Open(const char *pathname, int flags)
+{
+	assert(!IsDefined());
+
+	fd = ::open(pathname, flags);
+	return IsDefined();
+}
+
+bool
+FileDescriptor::OpenReadOnly(const char *pathname)
+{
+	return Open(pathname, O_RDONLY | O_NOCTTY | O_CLOEXEC);
+}
+
+#ifdef HAVE_POSIX
+
+bool
+FileDescriptor::OpenNonBlocking(const char *pathname)
+{
+	return Open(pathname, O_RDWR | O_NOCTTY | O_CLOEXEC | O_NONBLOCK);
+}
+
+bool
+FileDescriptor::CreatePipe(FileDescriptor &r, FileDescriptor &w)
+{
+	int fds[2];
+
+#ifdef HAVE_PIPE2
+	const int flags = O_CLOEXEC;
+	const int result = pipe2(fds, flags);
+#else
+	const int result = pipe(fds);
+#endif
+
+	if (result < 0)
+		return false;
+
+	r = FileDescriptor(fds[0]);
+	w = FileDescriptor(fds[1]);
+	return true;
+}
+
+void
+FileDescriptor::SetNonBlocking()
+{
+	assert(IsDefined());
+
+	int flags = fcntl(fd, F_GETFL);
+	fcntl(fd, F_SETFL, flags | O_NONBLOCK);
+}
+
+void
+FileDescriptor::SetBlocking()
+{
+	assert(IsDefined());
+
+	int flags = fcntl(fd, F_GETFL);
+	fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
+}
+
+#endif
+
+#ifdef USE_EVENTFD
+
+bool
+FileDescriptor::CreateEventFD(unsigned initval)
+{
+	assert(!IsDefined());
+
+	fd = ::eventfd(initval, EFD_NONBLOCK|EFD_CLOEXEC);
+	return fd >= 0;
+}
+
+#endif
+
+#ifdef USE_SIGNALFD
+
+bool
+FileDescriptor::CreateSignalFD(const sigset_t *mask)
+{
+	int new_fd = ::signalfd(fd, mask, SFD_NONBLOCK|SFD_CLOEXEC);
+	if (new_fd < 0)
+		return false;
+
+	fd = new_fd;
+	return true;
+}
+
+#endif
+
+#ifdef HAVE_INOTIFY_INIT
+
+bool
+FileDescriptor::CreateInotify()
+{
+#ifdef HAVE_INOTIFY_INIT1
+	int new_fd = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
+#else
+	int new_fd = inotify_init();
+#endif
+	if (new_fd < 0)
+		return false;
+
+#ifndef HAVE_INOTIFY_INIT1
+	SetNonBlocking();
+#endif
+
+	fd = new_fd;
+	return true;
+}
+
+#endif
+
+bool
+FileDescriptor::Rewind()
+{
+	assert(IsDefined());
+
+	return lseek(fd, 0, SEEK_SET) == 0;
+}
+
+off_t
+FileDescriptor::GetSize() const
+{
+	struct stat st;
+	return ::fstat(fd, &st) >= 0
+		? (long)st.st_size
+		: -1;
+}
+
+#ifdef HAVE_POSIX
+
+int
+FileDescriptor::Poll(short events, int timeout) const
+{
+	assert(IsDefined());
+
+	struct pollfd pfd;
+	pfd.fd = fd;
+	pfd.events = events;
+	int result = poll(&pfd, 1, timeout);
+	return result > 0
+		? pfd.revents
+		: result;
+}
+
+int
+FileDescriptor::WaitReadable(int timeout) const
+{
+	return Poll(POLLIN, timeout);
+}
+
+int
+FileDescriptor::WaitWritable(int timeout) const
+{
+	return Poll(POLLOUT, timeout);
+}
+
+#endif