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// Copyright 2018 The gVisor Authors.
//
// 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.
#ifndef GVISOR_TEST_UTIL_FILE_DESCRIPTOR_H_
#define GVISOR_TEST_UTIL_FILE_DESCRIPTOR_H_
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <algorithm>
#include <string>
#include "gmock/gmock.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_format.h"
#include "test/util/logging.h"
#include "test/util/posix_error.h"
#include "test/util/save_util.h"
namespace gvisor {
namespace testing {
// FileDescriptor is an RAII type class which takes ownership of a file
// descriptor. It will close the FD when this object goes out of scope.
class FileDescriptor {
public:
// Constructs an empty FileDescriptor (one that does not own a file
// descriptor).
FileDescriptor() = default;
// Constructs a FileDescriptor that owns fd. If fd is negative, constructs an
// empty FileDescriptor.
explicit FileDescriptor(int fd) { set_fd(fd); }
FileDescriptor(FileDescriptor&& orig) : fd_(orig.release()) {}
FileDescriptor& operator=(FileDescriptor&& orig) {
reset(orig.release());
return *this;
}
PosixErrorOr<FileDescriptor> Dup() const {
if (fd_ < 0) {
return PosixError(EINVAL, "Attempting to Dup unset fd");
}
int fd = dup(fd_);
if (fd < 0) {
return PosixError(errno, absl::StrCat("dup ", fd_));
}
MaybeSave();
return FileDescriptor(fd);
}
FileDescriptor(FileDescriptor const& other) = delete;
FileDescriptor& operator=(FileDescriptor const& other) = delete;
~FileDescriptor() { reset(); }
// If this object is non-empty, returns the owned file descriptor. (Ownership
// is retained by the FileDescriptor.) Otherwise returns -1.
int get() const { return fd_; }
// If this object is non-empty, transfers ownership of the file descriptor to
// the caller and returns it. Otherwise returns -1.
int release() {
int const fd = fd_;
fd_ = -1;
return fd;
}
// If this object is non-empty, closes the owned file descriptor (recording a
// test failure if the close fails).
void reset() { reset(-1); }
// Like no-arg reset(), but the FileDescriptor takes ownership of fd after
// closing its existing file descriptor.
void reset(int fd) {
if (fd_ >= 0) {
TEST_PCHECK(close(fd_) == 0);
MaybeSave();
}
set_fd(fd);
}
private:
// Wrapper that coerces negative fd values other than -1 to -1 so that get()
// etc. return -1.
void set_fd(int fd) { fd_ = std::max(fd, -1); }
int fd_ = -1;
};
// Wrapper around open(2) that returns a FileDescriptor.
inline PosixErrorOr<FileDescriptor> Open(std::string const& path, int flags,
mode_t mode = 0) {
int fd = open(path.c_str(), flags, mode);
if (fd < 0) {
return PosixError(errno, absl::StrFormat("open(%s, %#x, %#o)", path.c_str(),
flags, mode));
}
MaybeSave();
return FileDescriptor(fd);
}
// Wrapper around openat(2) that returns a FileDescriptor.
inline PosixErrorOr<FileDescriptor> OpenAt(int dirfd, std::string const& path,
int flags, mode_t mode = 0) {
int fd = openat(dirfd, path.c_str(), flags, mode);
if (fd < 0) {
return PosixError(errno, absl::StrFormat("openat(%d, %s, %#x, %#o)", dirfd,
path, flags, mode));
}
MaybeSave();
return FileDescriptor(fd);
}
} // namespace testing
} // namespace gvisor
#endif // GVISOR_TEST_UTIL_FILE_DESCRIPTOR_H_
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