[PATCH] Fix gdb crash due to SIGPIPE when the compile command fails

[Andrew Burgess]

* Bernd Edlinger <bernd.edlinger@hotmail.de> [2021-06-05 13:44:03 +0200]:

> On 6/4/21 3:39 PM, Tom Tromey wrote:
> >>>>>> "Bernd" == Bernd Edlinger <bernd.edlinger@hotmail.de> writes:
> > 
> > Bernd> I believe it is right to avoid the SIGPIPE before calling the plugin,
> > Bernd> instead of doing that in gcc-trunk, since we don't know which version
> > Bernd> we will be calling, and all versions I tried have failed like this.
> > 
> > That seems fine, but I think it would be better to install the handler
> > just when working with the plugin, and then uninstall it afterward, sort
> > of like what class scoped_ignore_sigttou does.
> > 
> 
> Okay, done, that works for me.
> 
> Is this OK?
> 
> 
> Thanks
> Bernd.
> 

> From 3bb3966601a89c18ea2700c3eae4aa4f4e195269 Mon Sep 17 00:00:00 2001
> From: Bernd Edlinger <bernd.edlinger@hotmail.de>
> Date: Wed, 2 Jun 2021 19:21:15 +0200
> Subject: [PATCH] Fix gdb crash due to SIGPIPE when the compile command fails
> 
> Due to the SIGPIPE the gdb process is killed here, which is
> not helpful.
> 
> 2021-06-02  Bernd Edlinger  <bernd.edlinger@hotmail.de>
> 
> 	* compile/compile.c (compile_to_object): Ignore SIGPIPE before calling
> 	the plugin.
> ---
>  gdb/compile/compile.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/gdb/compile/compile.c b/gdb/compile/compile.c
> index 8481d14..3431d4c 100644
> --- a/gdb/compile/compile.c
> +++ b/gdb/compile/compile.c
> @@ -633,6 +633,33 @@ struct compile_options
>    fputs_filtered (message, gdb_stderr);
>  }
>  
> +/* RAII class used to ignore SIGPIPE in a scope.  */
> +
> +class scoped_ignore_sigpipe
> +{
> +public:
> +  scoped_ignore_sigpipe ()
> +  {
> +#ifdef SIGPIPE
> +    m_osigpipe = signal (SIGPIPE, SIG_IGN);
> +#endif
> +  }
> +
> +  ~scoped_ignore_sigpipe ()
> +  {
> +#ifdef SIGTTOU

SIGPIPE?

Thanks,
Andrew


> +    signal (SIGPIPE, m_osigpipe);
> +#endif
> +  }
> +
> +  DISABLE_COPY_AND_ASSIGN (scoped_ignore_sigpipe);
> +
> +private:
> +#ifdef SIGPIPE
> +  sighandler_t m_osigpipe = NULL;
> +#endif
> +};
> +
>  /* Process the compilation request.  On success it returns the object
>     and source file names.  On an error condition, error () is
>     called.  */
> @@ -755,6 +782,10 @@ struct compile_options
>      fprintf_unfiltered (gdb_stdlog, "source file produced: %s\n\n",
>  			fnames.source_file ());
>  
> +  /* If we don't do this, then GDB simply exits
> +     when the compiler dies.  */
> +  scoped_ignore_sigpipe ignore_sigpipe;
> +
>    /* Call the compiler and start the compilation process.  */
>    compiler->set_source_file (fnames.source_file ());
>    ok = compiler->compile (fnames.object_file (), compile_debug);
> -- 
> 1.9.1
>