diff options
Diffstat (limited to 'externals/breakpad/src/common/linux/scoped_pipe.h')
-rw-r--r-- | externals/breakpad/src/common/linux/scoped_pipe.h | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/externals/breakpad/src/common/linux/scoped_pipe.h b/externals/breakpad/src/common/linux/scoped_pipe.h new file mode 100644 index 0000000000..25394c2aba --- /dev/null +++ b/externals/breakpad/src/common/linux/scoped_pipe.h @@ -0,0 +1,115 @@ +// Copyright 2022 Google LLC +// +// 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. +// * Neither the name of Google LLC nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// 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 COPYRIGHT +// OWNER 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. + +#ifndef COMMON_LINUX_SCOPED_PIPE_H_ +#define COMMON_LINUX_SCOPED_PIPE_H_ + +#include <stdint.h> +#include <string> + +namespace google_breakpad { + +// Small RAII wrapper for a pipe pair. +// +// Example (both ends of pipe in same process): +// ScopedPipe tmp; +// std::string line; +// if (tmp.Init() && tmp.Write(bytes, bytes_len)) { +// tmp.CloseWriteFd(); +// while (tmp.ReadLine(&line)) { +// std::cerr << line << std::endl; +// } +// } +// +// Example (reading output from a child process): +// ScopedPipe tmp; +// if (fork()) { +// // Parent process, read from the read end of the pipe. +// std::string line; +// while (tmp.ReadLine(line)) { +// // Process output... +// } +// // Close read pipe once done processing the output that we wanted, this +// // should ensure that the child process exits even if we didn't read all +// // of the output. +// tmp.CloseReadFd(); +// // Parent process should handle waiting for child to exit here... +// } else { +// // Child process, close the read fd and dup the write fd before exec'ing. +// tmp.CloseReadFd(); +// tmp.Dup2WriteFd(STDOUT_FILENO); +// tmp.Dup2WriteFd(STDERR_FILENO); +// execl("some-command", "some-arguments"); +// } +class ScopedPipe { + public: + ScopedPipe(); + ~ScopedPipe(); + + // Creates the pipe pair - returns false on error. + bool Init(); + + // Close the read pipe. This only needs to be used when the read pipe needs to + // be closed earlier. + void CloseReadFd(); + + // Close the write pipe. This only needs to be used when the write pipe needs + // to be closed earlier. + void CloseWriteFd(); + + // Reads characters until newline or end of pipe. On read failure this will + // close the read pipe, but continue to return true and read buffered lines + // until the internal buffering is exhausted. This will block if there is no + // data available on the read pipe. + bool ReadLine(std::string& line); + + // Writes bytes to the write end of the pipe, returns false and closes write + // pipe on failure. + bool WriteForTesting(const void* bytes, size_t bytes_len); + + // Calls the dup2 system call to replace any existing open file descriptor + // with number new_fd with a copy of the current write end file descriptor + // for the pipe. + int Dup2WriteFd(int new_fd) const; + + private: + int GetReadFd() const { + return fds_[0]; + } + + int GetWriteFd() const { + return fds_[1]; + } + + int fds_[2]; + std::string read_buffer_; +}; + +} // namespace google_breakpad + +#endif // COMMON_LINUX_SCOPED_PIPE_H_ |