Re: int target_query(what, aux, buf, offset, len)

[Andrew Cagney <ac131313 at redhat dot com>]

> Hello,
>
> Ref: The bottom of:
> http://sources.redhat.com/ml/gdb-patches/2003-10/msg00158.html
> and replies.
>
> has identified the need to update target_query().  The present interface looks like:
>
> int target_query (int /*char */ query_type,
>                   char *buf,
>                   char *outbuf,
>                   int *bufsiz);
>
> Where QUERY_TYPE and BUF are used to construct the query sent to the target.  I'd like to propose that it be changed to:
>
> long
> target_query (enum target_query_type query_type, const char *aux,
>               void *outbuf, CORE_ADDR offset, long length);

In the light of Joel's "upload/download" commands, and lessons (gdb/589) 
learn't from similar interfaces, and a realization that I need this for 
memory:

LONGEST target_read_partial (struct target_ops *target,
                             enum target_query_type query_type,
                             const char *annex,
                             void *inbuf,
                             CORE_ADDR offset,
                             LONGEST length);

LONGEST target_write_partial (struct target_ops *target,
                              enum target_query_type query_type,
                              const char *annex,
                              const void *outbuf,
                              CORE_ADDR offset,
                              LONGEST length);

- it takes an explicit target vector
- there are both read and write variants (instead of query)
- it, what the heck, takes a LONGEST
- it makes the fact that the method isn't expected to perform a full 
transfer explicit

> It attempts to query OFFSET:LENGTH bytes returning them in outbuf.
>
> The number of bytes actually transfered is returned, or zero if no more bytes are available, or -1 if the query isn't supported.  This allows short reads.
>
> Defined QUERY_TYPEs include QUERY_TYPE_T, QUERY_TYPE_P, others can be added later.  Some queries require suplemental information and that can be passed using the string buffer AUX.
>
> The "auxv" could be transfered using (QUERY_TYPE_PROC_AUXV, ...) or (QUERY_TYPE_PROC, "auxv", ...)
>
> thoughts,
> Andrew

I'll work up a patch.

Andrew