gdbserver: convert program_args to a single stringHEADmaster

This commit changes how gdbserver stores the inferior arguments from
being a vector of separate arguments into a single string with all of
the arguments combined together.

Making this change might feel a little strange; intuitively it feels
like we would be better off storing the arguments as a vector, but
this change is part of a larger series of work that aims to improve
GDB's inferior argument handling.  The full series was posted here:

  https://inbox.sourceware.org/gdb-patches/cover.1730731085.git.aburgess@redhat.com

But asking people to review a 14 patch series in unreasonable, so I'm
instead posting the patches in smaller batches.  This patch can stand
alone, and I do think this change makes sense on its own:

First, GDB already stores the inferior arguments as a single string,
so doing this moves gdbserver into line with GDB.  The common code
into which gdbserver calls requires the arguments to be a single
string, so currently each target's create_inferior implementation
merged the arguments anyway, so all this commit really does is move
the merging up the call stack, and store the merged result rather than
storing the separate parts.

However, the biggest reason for why this commit is needed, is an issue
with passing arguments from GDB to gdbserver when starting a new
inferior.

Consider:

  (gdb) set args $VAR
  (gdb) run
  ...

When using a native target the inferior will see the value of $VAR
expanded by the shell GDB uses to start the inferior.  However, if
using an extended-remote target the inferior will see literally $VAR,
the unexpanded name of the variable, the reason for this is that,
although GDB sends '$VAR' to gdbserver, when gdbserver receives this,
it converts this to '\$VAR', which prevents the variable from being
expanded by the shell.

The reason for this is that construct_inferior_arguments escapes all
special shell characters within its arguments, and it is
construct_inferior_arguments that is used to combine the separate
arguments into a single string.

In the future I will change construct_inferior_arguments so that
it can apply different escaping strategies.  When this happens we will
want to escape arguments coming from the gdbserver command line
differently than arguments coming from GDB (via a vRun packet), which
means we need to call construct_inferior_arguments earlier, at the
point where we know if the arguments came from the gdbserver command
line, or from the vRun packet.

This argument escaping issue is discussed in PR gdb/28392.

This commit doesn't fix any issues, nor does it change
construct_inferior_arguments to actually do different escaping, that
will all come later.  This is purely a restructuring.

There should be no user visible changes after this commit.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28392

Tested-By: Guinevere Larsen <guinevere@redhat.com>
Approved-By: Simon Marchi <simon.marchi@efficios.com>

0 files changed, 0 insertions, 0 deletions