[Bug binutils/29707] binutils c++filt reads a file with the first character \x00, it will wait for input and cause the program to block.

[nickc at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29707

Nick Clifton <nickc at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |NOTABUG
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |nickc at redhat dot com

--- Comment #1 from Nick Clifton <nickc at redhat dot com> ---
Hi,

  This is not a bug, it is expected behaviour.

  c++filt has two modes of operation.  If it is given strings on its command
  line then it decodes them one at a time and then exits.  If it is not
  given any strings to decode then it reads from the standard input stream 
  and decodes each line until it sees an end-of-file marker.

  Command line options do not count as strings to decode, so running 
  "c++filt --types" for example will still cause the program to read from
  the standard input.  In addition c++file supports the @-file syntax,
  allowing command line options and strings to decode to be placed into a
  file and then passed to c++filt via a command line option of @<name-of-file>.

  So in your test case, running: "c++filt @c++filt/crash01_timeout" causes
  the contents of c++filt/crash01_timeout to be read and processed.  Since
  the file is expected to contain text, not binary, any nul character (\x00)
  is treated as an end-of-file marker, and processing will stop at that
  character.

  Hence when the first character of c++filt/crash01_timeout is a nul character
  the entire file is treated as if it were empty, and the logic in c++filt
  sees that no strings were provided on the command line, and hence it starts
  to read from stdin, waiting for the user to provide input to decode.

  When the first character of c++filt/crash01_timeout is not a nul character
  the file is treated as having some contents which are passed back to c++filt
  to decode, and so once that is done c++filt terminates.

Cheers
  Nick

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