1 //===-- PipePosix.cpp -------------------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "lldb/Host/posix/PipePosix.h"
11 #include "lldb/Host/FileSystem.h"
12 #include "lldb/Host/HostInfo.h"
13 #include "lldb/Utility/SelectHelper.h"
14 #include "llvm/ADT/SmallString.h"
15 #include "llvm/Support/FileSystem.h"
17 #if defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 8))
18 #ifndef _GLIBCXX_USE_NANOSLEEP
19 #define _GLIBCXX_USE_NANOSLEEP
30 #include <sys/types.h>
34 using namespace lldb_private;
36 int PipePosix::kInvalidDescriptor = -1;
38 enum PIPES { READ, WRITE }; // Constants 0 and 1 for READ and WRITE
40 // pipe2 is supported by a limited set of platforms
41 // TODO: Add more platforms that support pipe2.
42 #if defined(__linux__) || (defined(__FreeBSD__) && __FreeBSD__ >= 10) || \
44 #define PIPE2_SUPPORTED 1
46 #define PIPE2_SUPPORTED 0
51 constexpr auto OPEN_WRITER_SLEEP_TIMEOUT_MSECS = 100;
53 #if defined(FD_CLOEXEC) && !PIPE2_SUPPORTED
54 bool SetCloexecFlag(int fd) {
55 int flags = ::fcntl(fd, F_GETFD);
58 return (::fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == 0);
62 std::chrono::time_point<std::chrono::steady_clock> Now() {
63 return std::chrono::steady_clock::now();
67 PipePosix::PipePosix()
68 : m_fds{PipePosix::kInvalidDescriptor, PipePosix::kInvalidDescriptor} {}
70 PipePosix::PipePosix(int read_fd, int write_fd) : m_fds{read_fd, write_fd} {}
72 PipePosix::PipePosix(PipePosix &&pipe_posix)
73 : PipeBase{std::move(pipe_posix)},
74 m_fds{pipe_posix.ReleaseReadFileDescriptor(),
75 pipe_posix.ReleaseWriteFileDescriptor()} {}
77 PipePosix &PipePosix::operator=(PipePosix &&pipe_posix) {
78 PipeBase::operator=(std::move(pipe_posix));
79 m_fds[READ] = pipe_posix.ReleaseReadFileDescriptor();
80 m_fds[WRITE] = pipe_posix.ReleaseWriteFileDescriptor();
84 PipePosix::~PipePosix() { Close(); }
86 Error PipePosix::CreateNew(bool child_processes_inherit) {
87 if (CanRead() || CanWrite())
88 return Error(EINVAL, eErrorTypePOSIX);
92 if (::pipe2(m_fds, (child_processes_inherit) ? 0 : O_CLOEXEC) == 0)
95 if (::pipe(m_fds) == 0) {
97 if (!child_processes_inherit) {
98 if (!SetCloexecFlag(m_fds[0]) || !SetCloexecFlag(m_fds[1])) {
99 error.SetErrorToErrno();
109 error.SetErrorToErrno();
110 m_fds[READ] = PipePosix::kInvalidDescriptor;
111 m_fds[WRITE] = PipePosix::kInvalidDescriptor;
115 Error PipePosix::CreateNew(llvm::StringRef name, bool child_process_inherit) {
116 if (CanRead() || CanWrite())
117 return Error("Pipe is already opened");
120 if (::mkfifo(name.data(), 0660) != 0)
121 error.SetErrorToErrno();
126 Error PipePosix::CreateWithUniqueName(llvm::StringRef prefix,
127 bool child_process_inherit,
128 llvm::SmallVectorImpl<char> &name) {
129 llvm::SmallString<PATH_MAX> named_pipe_path;
130 llvm::SmallString<PATH_MAX> pipe_spec((prefix + ".%%%%%%").str());
131 FileSpec tmpdir_file_spec;
132 tmpdir_file_spec.Clear();
133 if (HostInfo::GetLLDBPath(ePathTypeLLDBTempSystemDir, tmpdir_file_spec)) {
134 tmpdir_file_spec.AppendPathComponent(pipe_spec.c_str());
136 tmpdir_file_spec.AppendPathComponent("/tmp");
137 tmpdir_file_spec.AppendPathComponent(pipe_spec.c_str());
140 // It's possible that another process creates the target path after we've
141 // verified it's available but before we create it, in which case we
145 llvm::sys::fs::createUniqueFile(tmpdir_file_spec.GetPath(),
147 error = CreateNew(named_pipe_path, child_process_inherit);
148 } while (error.GetError() == EEXIST);
151 name = named_pipe_path;
155 Error PipePosix::OpenAsReader(llvm::StringRef name,
156 bool child_process_inherit) {
157 if (CanRead() || CanWrite())
158 return Error("Pipe is already opened");
160 int flags = O_RDONLY | O_NONBLOCK;
161 if (!child_process_inherit)
165 int fd = ::open(name.data(), flags);
169 error.SetErrorToErrno();
174 Error PipePosix::OpenAsWriterWithTimeout(
175 llvm::StringRef name, bool child_process_inherit,
176 const std::chrono::microseconds &timeout) {
177 if (CanRead() || CanWrite())
178 return Error("Pipe is already opened");
180 int flags = O_WRONLY | O_NONBLOCK;
181 if (!child_process_inherit)
184 using namespace std::chrono;
185 const auto finish_time = Now() + timeout;
187 while (!CanWrite()) {
188 if (timeout != microseconds::zero()) {
189 const auto dur = duration_cast<microseconds>(finish_time - Now()).count();
191 return Error("timeout exceeded - reader hasn't opened so far");
195 int fd = ::open(name.data(), flags);
197 const auto errno_copy = errno;
198 // We may get ENXIO if a reader side of the pipe hasn't opened yet.
199 if (errno_copy != ENXIO)
200 return Error(errno_copy, eErrorTypePOSIX);
202 std::this_thread::sleep_for(
203 milliseconds(OPEN_WRITER_SLEEP_TIMEOUT_MSECS));
212 int PipePosix::GetReadFileDescriptor() const { return m_fds[READ]; }
214 int PipePosix::GetWriteFileDescriptor() const { return m_fds[WRITE]; }
216 int PipePosix::ReleaseReadFileDescriptor() {
217 const int fd = m_fds[READ];
218 m_fds[READ] = PipePosix::kInvalidDescriptor;
222 int PipePosix::ReleaseWriteFileDescriptor() {
223 const int fd = m_fds[WRITE];
224 m_fds[WRITE] = PipePosix::kInvalidDescriptor;
228 void PipePosix::Close() {
229 CloseReadFileDescriptor();
230 CloseWriteFileDescriptor();
233 Error PipePosix::Delete(llvm::StringRef name) {
234 return FileSystem::Unlink(FileSpec{name.data(), true});
237 bool PipePosix::CanRead() const {
238 return m_fds[READ] != PipePosix::kInvalidDescriptor;
241 bool PipePosix::CanWrite() const {
242 return m_fds[WRITE] != PipePosix::kInvalidDescriptor;
245 void PipePosix::CloseReadFileDescriptor() {
248 m_fds[READ] = PipePosix::kInvalidDescriptor;
252 void PipePosix::CloseWriteFileDescriptor() {
255 m_fds[WRITE] = PipePosix::kInvalidDescriptor;
259 Error PipePosix::ReadWithTimeout(void *buf, size_t size,
260 const std::chrono::microseconds &timeout,
261 size_t &bytes_read) {
264 return Error(EINVAL, eErrorTypePOSIX);
266 const int fd = GetReadFileDescriptor();
268 SelectHelper select_helper;
269 select_helper.SetTimeout(timeout);
270 select_helper.FDSetRead(fd);
273 while (error.Success()) {
274 error = select_helper.Select();
275 if (error.Success()) {
276 auto result = ::read(fd, reinterpret_cast<char *>(buf) + bytes_read,
279 bytes_read += result;
280 if (bytes_read == size || result == 0)
283 error.SetErrorToErrno();
291 Error PipePosix::Write(const void *buf, size_t size, size_t &bytes_written) {
294 return Error(EINVAL, eErrorTypePOSIX);
296 const int fd = GetWriteFileDescriptor();
297 SelectHelper select_helper;
298 select_helper.SetTimeout(std::chrono::seconds(0));
299 select_helper.FDSetWrite(fd);
302 while (error.Success()) {
303 error = select_helper.Select();
304 if (error.Success()) {
306 ::write(fd, reinterpret_cast<const char *>(buf) + bytes_written,
307 size - bytes_written);
309 bytes_written += result;
310 if (bytes_written == size)
313 error.SetErrorToErrno();