ConnectionFileDescriptor::BytesAvailable reading too many command bytes

[vharron]

Summary

ConnectionFileDescriptor::BytesAvailable was reading multiple command
bytes from the command pipe but only processing the first. This
change only allows one byte to be read at a time, ensuring that all
get handled.

This isn't known to cause any bugs, but it might cause current/future
bugs.

[clayborg]

Looks good.

lldb/trunk/source/Host/posix/ConnectionFileDescriptorPosix.cpp

#endif
                 return eConnectionStatusTimedOut;
             }
             else if (num_set_fds > 0)
             {
                 if (FD_ISSET(handle, FD_SET_DATA(read_fds)))
                     return eConnectionStatusSuccess;
                 if (have_pipe_fd && FD_ISSET(pipe_fd, FD_SET_DATA(read_fds)))
                 {
-                    // We got a command to exit.  Read the data from that pipe:
-                    char buffer[16];
+                    // There is an interrupt or exit command in the command pipe
+                    // Read the data from that pipe:
+                    char buffer[1];
+
                     ssize_t bytes_read;
 
                     do
                     {
                         bytes_read = ::read(pipe_fd, buffer, sizeof(buffer));
                     } while (bytes_read < 0 && errno == EINTR);
 
                     switch (buffer[0])
                     {
                         case 'q':
                             if (log)
-                                log->Printf("%p ConnectionFileDescriptor::BytesAvailable() got data: %*s from the command channel.",
-                                            static_cast<void *>(this), static_cast<int>(bytes_read), buffer);
+                                log->Printf("%p ConnectionFileDescriptor::BytesAvailable() "
+                                            "got data: %c from the command channel.",
+                                            static_cast<void *>(this), buffer[0]);
                             return eConnectionStatusEndOfFile;
                         case 'i':
                             // Interrupt the current read
                             return eConnectionStatusInterrupted;
                     }
                 }
             }
         }