Re: [RFA] initialize err variable in load_section_callback()

[Andrew Cagney <cagney@gnu.org>]

Theodore A. Roth wrote:
> Hi,
> 
> I just encountered a problem with using the "load" command with a remote
> avr target. The first packet would be sent to the remote target and then
> gdb would just give up with this error message:
> 
>   (gdb) load
>   Loading section .text, size 0x1f8 lma 0x0
>   Sending packet: $M0,a:0c9446000c9463000c94#d7...Ack
>   Packet received: OK
>   Memory access error while loading section .text.
> 
> It looks like load_section_callback() in symfile.c is assuming that a
> call to target_write_memory_partial() will set the err variable.
> Unfortunately, that is not a valid assumption.
> 
> The attached patch got things working again, but this feels like a hack
> to me since target_write_memory_partial() should really be setting err
> to a sane value before returning.
> 
> Patch is against today's cvs mainline.

Here's the contract:
/* Make a single attempt at transfering LEN bytes.  On a successful
    transfer, the number of bytes actually transfered is returned and
    ERR is set to 0.  When a transfer fails, -1 is returned (the number
    of bytes actually transfered is not defined) and ERR is set to a
    non-zero error indication.  */
So the bug is further down the target stack.

Andrew

> 2004-10-19  Theodore A. Roth  <troth@openavr.org>
> 
> 	* symfile.c (load_section_callback): Initialize err to zero since
> 	target_write_memory_partial() may not set it in all situations.
> 
> Index: symfile.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/symfile.c,v
> retrieving revision 1.143
> diff -u -p -p -r1.143 symfile.c
> --- symfile.c	1 Oct 2004 10:23:09 -0000	1.143
> +++ symfile.c	19 Oct 2004 20:07:58 -0000
> @@ -1405,7 +1405,7 @@ load_section_callback (bfd *abfd, asecti
>  	  struct cleanup *old_chain;
>  	  CORE_ADDR lma = bfd_section_lma (abfd, asec) + args->load_offset;
>  	  bfd_size_type block_size;
> -	  int err;
> +	  int err = 0;
>  	  const char *sect_name = bfd_get_section_name (abfd, asec);
>  	  bfd_size_type sent;
>