Add and use CheckedReadFD(), CheckedWriteFD(), and CheckedReadFDAtEOF()

util/file/fd_io.h

Index: util/file/fd_io.h
diff --git a/util/file/fd_io.h b/util/file/fd_io.h
index 07f39b6d7587d5323112e5240ecb9352ff988b26..14481c93752c6fcec8e25566f37c5ea484017341 100644
--- a/util/file/fd_io.h
+++ b/util/file/fd_io.h
@@ -30,6 +30,8 @@ namespace crashpad {
 //!     have been read into \a buffer.
 //!
 //! \sa WriteFD
+//! \sa CheckedReadFD
+//! \sa CheckedReadFDAtEOF
 ssize_t ReadFD(int fd, void* buffer, size_t size);
 
 //! \brief Wraps `write()`, retrying when interrupted or following a short
@@ -43,8 +45,40 @@ ssize_t ReadFD(int fd, void* buffer, size_t size);
 //!     been written to \a fd.
 //!
 //! \sa ReadFD
+//! \sa CheckedWriteFD
 ssize_t WriteFD(int fd, const void* buffer, size_t size);
 
+//! \brief Wraps ReadFD(), ensuring that exactly \a size bytes are read.
+//!
+//! If \a size is out of the range of possible `read()` return values, if the
+//! underlying ReadFD() fails, or if other than \a size bytes were read, this
+//! function causes execution to terminate without returning.
+//!
+//! \sa CheckedWriteFD
+//! \sa ReadFD
+//! \sa CheckedReadFDAtEOF
+void CheckedReadFD(int fd, void* buffer, size_t size);
+
+//! \brief Wraps WriteFD(), ensuring that exactly \a size bytes are written.
+//!
+//! If \a size is out of the range of possible `write()` return values, if the
+//! underlying WriteFD() fails, or if other than \a size bytes were written,
+//! this function causes execution to terminate without returning.
+//!
+//! \sa CheckedReadFD
+//! \sa WriteFD
+void CheckedWriteFD(int fd, const void* buffer, size_t size);
+
+//! \brief Wraps ReadFD(), ensuring that it indicates end-of-file.
+//!
+//! Attempts to read a single byte from \a fd, expecting no data to be read. If
+//! the underlying ReadFD() fails, or if a byte actually is read, this function
+//! causes execution to terminate without returning.
+//!
+//! \sa CheckedReadFD
+//! \sa ReadFD
+void CheckedReadFDAtEOF(int fd);
+
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_FILE_FD_IO_H_