secdiscard.cpp: Use getmntent and my newfound C++ knowledge.
Bug: 19706593
Change-Id: I6254e0339ab42fdbecda80c6f37e64c323329190
diff --git a/AutoCloseFD.h b/AutoCloseFD.h
new file mode 100644
index 0000000..f9d7c86
--- /dev/null
+++ b/AutoCloseFD.h
@@ -0,0 +1,48 @@
+/*
+ * 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 <string>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+// File descriptor which is automatically closed when this object is destroyed.
+// Cannot be copied, since that would cause double-closes.
+class AutoCloseFD {
+public:
+ AutoCloseFD(const char *path, int flags = O_RDONLY, int mode = 0):
+ fd{TEMP_FAILURE_RETRY(open(path, flags | O_CLOEXEC, mode))} {}
+ AutoCloseFD(const std::string &path, int flags = O_RDONLY, int mode = 0):
+ AutoCloseFD(path.c_str(), flags, mode) {}
+ ~AutoCloseFD() {
+ if (fd != -1) {
+ int preserve_errno = errno;
+ if (close(fd) == -1) {
+ SLOGE("close(2) failed: %s", strerror(errno));
+ };
+ errno = preserve_errno;
+ }
+ }
+ AutoCloseFD(const AutoCloseFD&) = delete;
+ AutoCloseFD& operator=(const AutoCloseFD&) = delete;
+ explicit operator bool() {return fd != -1;}
+ int get() const {return fd;}
+private:
+ const int fd;
+};
+