1 files changed, 132 insertions, 0 deletions
diff --git a/src/common/linux/scoped_pipe.cc b/src/common/linux/scoped_pipe.cc
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+++ b/src/common/linux/scoped_pipe.cc
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+// 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.
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>  // Must come first
+#endif
+
+#include "common/linux/scoped_pipe.h"
+
+#include <unistd.h>
+
+#include "common/linux/eintr_wrapper.h"
+
+namespace google_breakpad {
+
+ScopedPipe::ScopedPipe() {
+  fds_[0] = -1;
+  fds_[1] = -1;
+}
+
+ScopedPipe::~ScopedPipe() {
+  CloseReadFd();
+  CloseWriteFd();
+}
+
+bool ScopedPipe::Init() {
+  return pipe(fds_) == 0;
+}
+
+void ScopedPipe::CloseReadFd() {
+  if (fds_[0] != -1) {
+    close(fds_[0]);
+    fds_[0] = -1;
+  }
+}
+
+void ScopedPipe::CloseWriteFd() {
+  if (fds_[1] != -1) {
+    close(fds_[1]);
+    fds_[1] = -1;
+  }
+}
+
+bool ScopedPipe::ReadLine(std::string& line) {
+  // Simple buffered file read. `read_buffer_` stores previously read bytes, and
+  // we either return a line from this buffer, or we append blocks of read bytes
+  // to the buffer until we have a complete line.
+  size_t eol_index = read_buffer_.find('\n');
+
+  // While we don't have a full line, and read pipe is valid.
+  while (eol_index == std::string::npos && GetReadFd() != -1) {
+    // Read a block of 128 bytes from the read pipe.
+    char read_buf[128];
+    ssize_t read_len = HANDLE_EINTR(
+      read(GetReadFd(), read_buf, sizeof(read_buf)));
+    if (read_len <= 0) {
+      // Pipe error, or pipe has been closed.
+      CloseReadFd();
+      break;
+    }
+
+    // Append the block, and check if we have a full line now.
+    read_buffer_.append(read_buf, read_len);
+    eol_index = read_buffer_.find('\n');
+  }
+
+  if (eol_index != std::string::npos) {
+    // We have a full line to output.
+    line = read_buffer_.substr(0, eol_index);
+    if (eol_index < read_buffer_.size()) {
+      read_buffer_ = read_buffer_.substr(eol_index + 1);
+    } else {
+      read_buffer_ = "";
+    }
+
+    return true;
+  }
+
+  if (read_buffer_.size()) {
+    // We don't have a full line to output, but we can only reach here if the
+    // pipe has closed and there are some bytes left at the end, so we should
+    // return those bytes.
+    line = std::move(read_buffer_);
+    read_buffer_ = "";
+
+    return true;
+  }
+
+  // We don't have any buffered data left, and the pipe has closed.
+  return false;
+}
+
+int ScopedPipe::Dup2WriteFd(int new_fd) const {
+  return dup2(fds_[1], new_fd);
+}
+
+bool ScopedPipe::WriteForTesting(const void* bytes, size_t bytes_len) {
+  ssize_t r = HANDLE_EINTR(write(GetWriteFd(), bytes, bytes_len));
+  if (r != static_cast<ssize_t>(bytes_len)) {
+    CloseWriteFd();
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace google_breakpad